Industrial Applications

10 Industrial Applications

David

S.

Breslow

Hercules Research Center Hercules Inc. Wilmington, Delaware

I. II. III. IV. V. VI. VII. VIII. IX. X. XI.

P h o t o r e s i s t s a n d Printing P l a t e s Rubber Vulcanization Cross-linking of O t h e r P o l y m e r s Coupling Agents Modification of P o l y m e r Surfaces Tire-Cord Adhesives Dyes Polymer Additives Blowing Agents and Gas Generators Explosives and Propellants Biological Activity A. Pharmaceutical Applications B. Herbicides and Pesticides X I I . P o l y m e r i z a t i o n Initiators XIII. Miscellaneous Applications References

491 499 502 503 504 505 5

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6

507 508 509 511 511 514 516 517 517

I. P h o t o r e s i s t s a n d P r i n t i n g P l a t e s O n e of the first major u s e s for organic azides involved the p h o t o c h e m i c a l cross-linking of polymeric s y s t e m s (7). Since the azide g r o u p a b s o r b s only short-wavelength light (286-288 n m ) , most of the w o r k has c o n c e n ­ trated o n aryl azides. H e r e , irradiation excites the aromatic s y s t e m , which then transfers energy to the azide function (2). Although the initial spin state often s e e m s to be in question, m a n y intermolecular reactions of AZIDES AND NITRENES Reactivity and Utility

491

Copyright © 1984 by Academic Press, Inc. All rights of reproduction in any form reserved ISBN 0-12-633480-3

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D a v i d S. B r e s l o w

arylnitrenes involve the triplet state; h o w e v e r , the cyclization of 2-azido­ biphenyl to c a r b a z o l e , an intramolecular reaction, involves the singlet nitrene (3). E a s t m a n K o d a k m a r k e t s a photoresist b a s e d on cyclized r u b b e r , with 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone (1) as b o t h the p h o t o a b s o r b e r and cross-linking agent (4, 5 ) ; the e x t e n d e d conjugated s y s t e m increases the extinction coefficient and shifts the absorption to longer w a v e l e n g t h s . E x t e n s i o n into the visible region can b e obtained with the cinnamylidene derivative (2) ( / ) .

ο

2

T h e m e c h a n i s m of cross-linking is not at all clear. Cyclized r u b b e r contains considerable u n s a t u r a t i o n (6). According to D e l z e n n e (7), a bicyclic p o l y m e r containing 10% u n r e a c t e d isoprene units gives the best results. A s already n o t e d , m o s t intermolecular arylnitrene reactions in­ volve the triplet state. T o the t h r e e triplet-state reactions in solution— insertion into a C — Η b o n d to form a s e c o n d a r y a m i n e , abstraction of t w o h y d r o g e n s to form a primary a m i n e , and " d i m e r i z a t i o n " to form an azo c o m p o u n d — a fourth m u s t b e a d d e d for cyclized r u b b e r — a d d i t i o n to the double b o n d to form an aziridine. Of t h e s e , insertion is an inefficient p r o c e s s and the major p r o d u c t s with saturated h y d r o c a r b o n s are arylamines a n d / o r a z o c o m p o u n d s , depending on the n a t u r e of the aryl g r o u p . Reiser a n d c o - w o r k e r s h a v e s h o w n , h o w e v e r , that in a solid p o l y m e r matrix the r e a c t i o n s are quite different (7). F o r e x a m p l e , 1-azidonaphthalene in p o l y s t y r e n e gave a 9 5 % total yield of a m i n e , 9 3 % of which w a s s e c o n d a r y amine attached to the p o l y m e r . T h e difference b e t w e e n the reaction in solution and in a p o l y m e r w a s attributed to the increased triplet lifetime in the polymer ( / ~ 10~ s in solution and 0.85 s in 3

1/2

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polystyrene) and the " r i g i d i t y " of the polymer, allowing the t w o radicals formed by Η abstraction to invert spins and couple (a t w o - s t e p C — Η insertion) before separating by diffusion. A s e x p e c t e d of free radicals, the reaction w a s inhibited by oxygen. With cyclized r u b b e r the total amine yield w a s 9 0 % , with 6 7 % s e c o n d a r y amine attached to the p o l y m e r . T h u s , although triplet insertion a p p e a r s to be the major reaction, o t h e r reactions are possible, and it is not clear w h e t h e r an aziridine, formed by reaction with the residual unsaturation in cyclized rubber, would h a v e b e e n ana­ lyzed as secondary amine. Efros and Y u r r e seem to be the only o n e s w h o h a v e reported on the reaction of the diazide 1 with cyclized r u b b e r (8). T h e y claimed that the cross-linking reaction of 1 involved a nitrene singlet (since it w a s unaffected by h y d r o q u i n o n e or phenyl-/3-naphthylamine), which reacted with the unsaturation in cyclized r u b b e r to form aziridines (a nitrene triplet could h a v e d o n e the s a m e ) ; their evidence w a s b a s e d on the similarity of the ultraviolet (UV) spectra of the p o l y m e r (before insolubilization) and the dimethylamino analog of 1. An intense yellow color of the isolated polymer w a s noted. T h e s e proposals are not necessarily mutually exclusive. T h e r e are nu­ m e r o u s s t a t e m e n t s in the literature that the p r o d u c t s of an azide reaction d e p e n d on both the structure of the azide and the nature of the m e d i u m . T h u s 4-azidobiphenyl gave an 8 0 % yield of azobiphenyl w h e n irradiated in b e n z e n e , w h e r e a s phenyl azide and p-chlorophenyl azide gave essen­ tially n o n e . p - M e t h o x y p h e n y l azide gave an 18% yield of a z o c o m p o u n d in b e n z e n e and an 82% yield in tetrahydrofuran ( T H F ) or acetonitrile (9). T h u s 1-azidonaphthalene, used by Reiser (7), may h a v e been a p o o r model for 1. T h e s e cross-linking reactions are quite slow, inasmuch as t h e q u a n t u m yield for azide d e c o m p o s i t i o n is less than o n e , and at least t w o nitrenes are required for cross-linking. Cross-linking can be accelerated by the use of triplet sensitizers, which also e x t e n d the absorption range into longer w a v e l e n g t h s . T h u s , in the cyclized r u b b e r - 1 system, 1,8-dinitropyrene i n c r e a s e d t h e speed threefold b y a triplet-triplet energy-transfer m e c h a ­ nism (5). Merrill and U n r u h (70) r e p o r t e d that a n o t h e r w a y to increase speed is to attach an azide to the p o l y m e r b a c k b o n e . A partially h y d r o l y z e d poly (vi­ nyl acetate) c o n d e n s e d with 3- or 4-azidophthalic a n h y d r i d e g a v e poly­ m e r s 2 5 - 1 0 0 times m o r e sensitive than a standard photoresist, polyvinyl c i n n a m a t e ) , and this could b e increased 4- to 5-fold by the use of a sensi­ tizer. Similar results w e r e obtained with s t y r e n e - m a l e i c a n h y d r i d e copol­ y m e r esterified with m-azidobenzyl alcohol or /?-azidophenoxyethanol. L a r i d o n and c o - w o r k e r s u s e d an azidosulfonyl chloride to attach the aryl azide to a Bisphenol A - e p i c h l o r o h y d r i n b a c k b o n e and also a t t a c h e d

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D a v i d S. B r e s l o w

the p h o t o s e n s i t i z e r (imidazoles, o x a z o l e s , etc.) to obtain high sensitivity (11)· D e l z e n n e and L a r i d o n p r e p a r e d p o l y m e r s by interfacial c o n d e n s a t i o n of azidoaryl bis(carbonyl chlorides) with diols or diamines, for e x a m p l e , 5-azidoisophthaloyl chloride with Bisphenol A (12). Unfortunately, it is difficult to c o m p a r e their sensitivities with Merrill and U n r u h ' s , although large a m o u n t s (58%) of M i c h l e r ' s k e t o n e gave as m u c h as a 38-fold in­ c r e a s e in sensitivity o v e r that of the unsensitized polymer. D e l z e n n e and L a r i d o n (12) suggested that the cross-linking m e c h a n i s m involves the formation of a z o c o m p o u n d s , b a s e d on the yellow color. A z o c o m p o u n d s can b e formed by dimerization of singlet or triplet nitrenes or by reaction of a nitrene with an azido group (13, 14; see also C h a p t e r 3). Reiser and c o - w o r k e r s h o w e v e r , did not report the formation of any azo c o m p o u n d s in their m o d e l e x p e r i m e n t s (7). A n o t h e r p r o c e d u r e used radical polymerization of u n s a t u r a t e d aryl azides. According to D e l z e n n e ( / ) , the most suitable material is a terpolym e r of m e t h y l and η-butyl m e t h a c r y l a t e with 2-(4-azidobenzoyl)oxypropyl m e t h a c r y l a t e . N o t surprisingly, s o m e azide functionality is lost during polymerization, p r e s u m a b l y by 1,3-dipolar cycloaddition of the azide to the activated m e t h a c r y l a t e double b o n d (75). P e r h a p s the best evidence for the m e c h a n i s m of cross-linking of an aryl azide p o l y m e r c o m e s from the work of T s u d a et al. (16). T h e y h y d r o l y z e d the photolysis product of p o l y v i n y l p - a z i d o b e n z o a t e ) and isolated poly­ v i n y l alcohol) and its /?-aminobenzoate ester, free /?-aminobenzoic acid, 4 , 4 ' - a z o b e n z e n e d i c a r b o x y l i c acid, and its N - o x i d e . In a s u b s e q u e n t ar­ ticle h o w e v e r , they a d d e d s e c o n d a r y amines to the list of p r o d u c t s (77). T h u s b o t h insertion and a z o formation w e r e responsible for cross-linking in this s y s t e m . M u c h less has b e e n r e p o r t e d on the use of sulfonyl azides in p h o t o r e ­ sists, probably b e c a u s e they a b s o r b only at short wavelengths (—270 nm), but p e r h a p s also b e c a u s e of the p o o r yields and complex reactions re­ p o r t e d in the literature (18). Agfa-Gevaert apparently b e c a m e interested in this a r e a w h e n H o l t s c h m i d t and Oertel (19) first p r e p a r e d ra-azidosulfonylphenyl i s o c y a n a t e , which w a s used to functionalize hydroxylcontaining p o l y m e r s (20). S u b s e q u e n t l y , h o w e v e r , they switched to the use of ra-azidosulfonylbenzoyl chloride (27), p e r h a p s b e c a u s e they found that the azidosulfonyl isocyanate is unstable, p r e s u m a b l y b e c a u s e of a 1,3-dipolar cycloaddition reaction b e t w e e n the t w o functional groups (22). Although they claimed p o l y m e r s broadly in their earlier p a t e n t s , in later p a t e n t s (27) Agfa-Gevaert limited their claims to p o l y m e r s contain­ ing h y d r o x y l , p h e n y l , pyridyl, or lactam g r o u p s . Since in m o s t of their p a t e n t s they u s e d M i c h l e r ' s k e t o n e as a triplet photosensitizer, this raises

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interesting questions a b o u t the m e c h a n i s m of cross-linking. It is k n o w n that s e c o n d a r y alcohols are readily d e h y d r o g e n a t e d to k e t o n e s by sul­ fonyl azides in a radical chain reaction involving a triplet nitrene (18). T h e Agfa-Gevaert p a t e n t discloses a m a x i m u m cross-linking rate for the hydroxyl-containing p o l y m e r s , sensitized with Michler's k e t o n e , at an O H / S 0 N ratio of 4 / 1 , with the rate decreasing at a lower ratio b e c a u s e of an insufficiency of O H g r o u p s . It would appear, therefore, that h e r e , t o o , solution and p o l y m e r matrix chemistry m a y b e different; isopropanol and methanesulfonyl azide in solution are reported to form a c e t o n e and methanesulfonamide quantitatively, although methanol and tosyl azide give a 4 4 % yield of h y d r o x y l a m i n e derivative by Η — Ο insertion. T h u s the cross-linking reaction m u s t involve insertion, free radical chemistry, or an aldol-type c o n d e n s a t i o n b e t w e e n carbonyl groups and active h y d r o g e n s ; h o w e v e r , the conditions of photolysis s e e m to b e t o o mild for aldol con­ densations to o c c u r . In a n y e v e n t , hydroxyl-containing p o l y m e r s a p p e a r to b e faster than a n y of the o t h e r s claimed. P o l y s t y r e n e s and polypyridines p r o b a b l y r e a c t with triplet sulfonylnitrene in a fashion similar to that of p h e n y l n i t r e n e , although sulfonyl azides react with pyridine thermally to form the zwitterion, p r e s u m a b l y via the singlet nitrene [Eq. (1)] (18). T h e reaction of azides with lactams has not b e e n r e p o r t e d . 2

3

(1) Although sensitizers o t h e r than M i c h l e r ' s k e t o n e h a v e b e e n u s e d (23), the k e t o n e s e e m s to b e preferred. According to Stuber et al. (24), h o w ­ ever, M i c h l e r ' s k e t o n e c a n n o t be a sensitizer for sulfonyl azides b y the usual triplet-triplet m e c h a n i s m . T h e triplet state of an arenesulfonyl azide is —79 k c a l / m o l e , while that of M i c h l e r ' s k e t o n e is 61 kcal; t h u s t r i p l e t triplet energy transfer would be e n d o t h e r m i c by 17 kcal. T h e m e c h a n i s m involved in the energy transfer is not k n o w n , but excitation of a groundstate c o m p l e x has been suggested. A s an acid-proof etching resist for printed circuits or printing plates, the reaction p r o d u c t of chlorosulfonated polyethylene with sodium azide has b e e n r e c o m m e n d e d ; since the p o l y m e r is highly chlorinated and contains few sulfonyl chloride g r o u p s , the azide content w a s low (25). Poly(vinylbenzyl chloride) has been used similarly (26). Although the s y s t e m s described thus far would b e suitable for the " c l a s s i c a l " photoresist u s e s , circuit b o a r d s , lithographic printing, and the like, in the a r e a of s u b m i c r o m e t e r lithography (i.e., microfabrication of s e m i c o n d u c t o r d e v i c e s ) , the trend has b e e n to finer lines ( < 1 μτη) and higher resolution. This has led to the u s e of dry d e v e l o p m e n t with a

D a v i d S. B r e s l o w

496

p l a s m a . In p l a s m a d e v e l o p m e n t the important factor is the difference in rate of d e c o m p o s i t i o n of the e x p o s e d and u n e x p o s e d a r e a s . T s u d a et al. (17, 27a) r e p o r t e d that t h e d e c o m p o s i t i o n p r o d u c t s of aryl azides increase t h e e t c h r e s i s t a n c e of p o l y m e r s t o w a r d an o x y g e n p l a s m a . T h u s polyOne thyl i s o p r o p e n y l ketone) containing 4,4'-bis(azidophenyl) sulfide w a s c o a t e d o n t o a silicon wafer, irradiated by electron b e a m or U V light, and d e v e l o p e d with an o x y g e n p l a s m a . A n etch-rate difference b e t w e e n ex­ p o s e d a n d u n e x p o s e d a r e a s (after removing u n r e a c t e d azide) of 2 - 2 . 5 yielded lines n a r r o w e r t h a n 0.3 μ π ι from electron b e a m and 0.5 μπι from U V after etching t h e silicon wafer with a c a r b o n t e t r a f l u o r i d e - o x y g e n p l a s m a . This s y s t e m is being d e v e l o p e d by T o k y o O h k a K o g y o . H i t a c h i h a s p a t e n t e d the u s e of 4,4'-bis(azidophenyl) sulfide as a sensi­ tizer for photoinsolubilization of a novolak resin; the resulting p o l y m e r w a s so resistant t o dry etching that it could be u s e d as a m a s k (27b). T h e s y s t e m s d i s c u s s e d thus far lead to negative-working p h o t o r e s i s t s , (i.e., t h e light-struck a r e a s are cross-linked and, in lithography, b e c o m e t h e printing a r e a s ) . F o r s o m e u s e s , h o w e v e r , positive-working plates are desired, in w h i c h t h e light-struck a r e a s m u s t be r e m o v e d . Fuji P h o t o Film h a s p a t e n t e d a s y s t e m in w h i c h an alcohol-soluble p o l y a m i d e , p r e p a r e d b y treating a 6- or 6,6-nylon with f o r m a l d e h y d e , is p h o t o l y z e d in t h e p r e s e n c e of an alkali-soluble aryl azide, such as 4,4'-diazidostilbene-2,2'disulfonic acid o r p - a z i d o b e n z o i c acid (28). Since t h e light-struck a r e a s b e c o m e soluble in diluted b a s e , this is strong e v i d e n c e that t h e reaction involves a t w o - s t e p insertion (presumably the stilbene azide would react only o n c e ) . It is c o n c e i v a b l e that t h e coupling is b e t w e e n the free amino g r o u p s formed during photolysis and the p o l y m e r methylol g r o u p s , but this r e a c t i o n is normally carried out u n d e r acidic conditions. T h e r e a r e , of c o u r s e , m a n y o t h e r imaging p r o c e d u r e s . T h e U p j o h n C o m p a n y a n n o u n c e d a n e w photoresist in 1973 (24, 29), b a s e d on t h e sulfonyl azide chemistry developed by Agfa-Gevaert. Their s y s t e m in­ volved t h e u s e of a methyl vinyl e t h e r / m a l e i c a n h y d r i d e (1/1) alternating c o p o l y m e r ( M W 5 χ 10 ) reacted with 2-hydroxyethyl /7-azidosulfonylp h e n y l c a r b a m a t e [Eq. (2)]. T h e p o l y m e r w a s c o a t e d on a s u p p o r t , irradi­ ated with 254-nm light through a m a s k , w a s h e d with a k e t o n e solvent or 5

(2)

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dilute b a s e to r e m o v e u n e x p o s e d p o l y m e r , and t h e n t r e a t e d with a basic dye to d e v e l o p t h e image. This short-wavelength light would g e n e r a t e singlet sulfonylnitrene, w h i c h could t h e n cross-link via a c o n c e r t e d C — Η b o n d insertion. M i c h l e r ' s k e t o n e w a s r e c o m m e n d e d as a sensitizer to allow t h e u s e of longer-wavelength light, but with this s y s t e m t h e speed w a s d e c r e a s e d by the sensitizer. Various modifications h a v e b e e n de­ scribed, including the use of a built-in sensitizer, obtained by reacting the p o l y m e r with the reaction p r o d u c t of iraft5^2,5-dimethoxy-4'-isocyanatostilbene and ethylene glycol (3) (30). T h e p r o d u c t has b e e n w i t h d r a w n from the m a r k e t .

3

K o s a r (31) described a n u m b e r of p h o t o s y s t e m s based on a z i d e s . Sev­ eral aryl azides h a v e b e e n r e c o m m e n d e d for photocross-linking of syn­ thetic p o l y m e r s (31, p . 113) for silk-screen printing. Water-soluble a z i d e s , such as 4,4'-diazidostilbene-2,2'-disulfonic acid, h a v e b e e n suggested as insolubilizing agents for gelatin, gum arabic, and the like b e c a u s e of their excellent storage stability in presensitized lithographic printing plates (31, p p . 330-336). Colored images can be obtained by using an aryl azide as an oxidative or dehydrogenating agent for coupling a /7-phenylenediamine with α-naphthol or o t h e r c o m p o u n d s containing reactive m e t h y l e n e or methine groups [Eq. (3)]. Better results are obtained by substituting pdialkylaminophenyl azides for the diamine plus azide (31, p . 359). OH

(3)

498

D a v i d S. B r e s l o w

A m e r i c a n C y a n a m i d has several p a t e n t s on the formation of images by irradiation of a ρ e n - n a p h t h a l e n e azide (4) in poly (vinyl chloride) (32). T h e image is p r o b a b l y formed by an interaction similar to that in E q . (3) to form a blue to gray-black d y e . T h e image is fixed by evaporating the u n r e a c t e d azide in a s t r e a m of hot air.

4 X = N ; OH; NH ; NHCOR 3

2

A n o t h e r p r o c e d u r e , k n o w n as the vesicular p r o c e s s , can be used for imaging (31, p . 276). H e r e advantage is t a k e n of the nitrogen liberated on photolysis; a p o l y m e r containing, usually, a diazo c o m p o u n d is irradiated and t h e n h e a t e d , the dissolved gas expanding to form tiny vesicles that scatter light and form the image. H e r e , t o o , azides h a v e a stability advan­ tage o v e r diazo c o m p o u n d s , and E a s t m a n K o d a k has p a t e n t e d several t y p e s , l,4-naphthoquinone-2,3-diazide (5) (33) and 2-[diazido-s-triazenyl]1-naphthol (6) (34).

5

6

Hitachi has p a t e n t e d a p r o c e s s for making raster dots on color-televi­ sion picture tubes involving azide photolysis (35). A water-soluble azide, such as 4,4'-diazidostilbene-2,2'-disulfonic acid, is irradiated through a s h a d o w m a s k . T h e u n r e a c t e d p o l y m e r is w a s h e d away with w a t e r , the tube c o a t e d with c a r b o n black, and the cross-linked p o l y m e r peeled off to leave the r a s t e r d o t s ; this is essentially a reversal p r o c e s s , similar to using a positive resist.

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II. R u b b e r V u l c a n i z a t i o n Since azidoformates d e c o m p o s e thermally at a convenient t e m p e r a t u r e to form nitrenes, w h i c h insert into h y d r o c a r b o n C — Η b o n d s (36, 37), their u s e for e l a s t o m e r cross-linking w a s o n e of the first investigated by H e r c u ­ les. In fact, it w a s a search for n e w vulcanizing agents for e t h y l e n e p r o p y l e n e elastomers (EPM) that led to the study of nitrenes. F o r most of this w o r k t e t r a m e t h y l e n e bis(azidoformate) (TBAF) w a s u s e d , although the p u r e c o m p o u n d is s o m e w h a t shock sensitive (38). H o w e v e r , it could be handled safely in solution or on a support, such as c a r b o n black. Table I s h o w s the results obtained by vulcanizing a variety of c o m m e r ­ cial e l a s t o m e r s with T B A F (38). In addition, qualitative results s h o w e d the cross-linking of a poly sulfide r u b b e r , p o l y u r e t h a n e s , and polyacrylates. All the properties s h o w n in Table I are c o m p a r a b l e or superior to those obtained with commercial vulcanizing agents. T h e ability to vulcanTABLE I P h y s i c a l P r o p e r t i e s of E l a s t o m e r s C u r e d with T B A F

Elastomer Natural rubber cis-\ , 4 - P o l y i s o p r e n e cis-l , 4 - P o l y b u t a d i e n e Styrene-butadiene copolymer ( S B R 1500) Polyisobutylene ( V i s t a n e x L-80) B u t y l r u b b e r (Enjay B u t y l 325) Butadiene-acrylonitrile c o p o l y m e r (Paracril B) Polychloroprene (Neoprene W) Chlorosulfonated polyethylene ( H y p a l o n 20) EPM EPDM (Nordel)^

a

Tensile strength

Elong­ ation

(psi)

(%)

Shore A hardness

415 430 520

3595 2800 1440

320 300 140

65 67 73

0 5 0

430

2925

275

68

0

—

210

1115 1275

530 370

45 47

15 5

750 1510

2985 3455

205 170

69 79

0 0

1080

2015 2895 3220

165 225 690

72 69 50

10 15 20

100% Modulus

Break set (%)

6

— —

* R e c i p e : P o l y m e r (as s h o w n ) , 100; H A F black (Philblack O), 4 7 . 5 ; T B A F ( 5 0 % o n H A F b l a c k ) , 5.0. C u r e d 45 min at 310°F. C o n t a i n i n g 40 p a r t s M A F b l a c k (Philblack A) a n d 30 p a r t s H A F b l a c k (Philblack O ) , 5 p a r t s n a p h t h e n i c oil (Circosol 42 X H ) , a n d 5 p a r t s zinc o x i d e . T B A F , 4 parts. C o n t a i n i n g 20 p a r t s n a p h t h e n i c oil ( N e c t o n 60). b

c

d

500

D a v i d S. B r e s l o w T A B L E II Black-Loaded E P M Formulation Cured with T B A F Recipe E P M (Vistalon 404) S A F b l a c k ( V u l c a n 6) T h e r m a l b l a c k (Sterling M T ) A n t i o x i d a n t (Agerite R e s i n D) Z i n c o x i d e ( P r o t o x 166) P e t r o l e u m jelly Paraffin w a s Sulfur ( T u b e b r a n d ) T B A F (30% on H A F )

100 35 25 1.0 5.0 1.0 1.0 0.2 8.35

C o m p o u n d M o o n e y v i s c o s i t y ( M L - 4 at 212°F) M o o n e y s c o r c h ( M S at 250°F), min to 5 point rise P r e s s - c u r e d at 310°F for 45 min

80 15

A i r o v e n aged at 300°F Test

Unaged

5 days

8 days

3 0 0 % m o d u l u s (psi) T e n s i l e s t r e n g t h (psi) E l o n g a t i o n (%) Shore A hardness B r e a k set (%) C o m p r e s s i o n set (70 h at 250°F) Graves tear strength at 212°F

1150 2275 505 58 15 50

2030 2185 310 64 5

2120 2180 300 64 5

—

—

—

—

2

95

ize p o l y i s o b u t y l e n e , and to cross-link p o l y p r o p y l e n e , w a s the first evi­ d e n c e that C — Η insertion is a singlet nitrene reaction, since t h e s e poly­ mers d e g r a d e r a t h e r than cross-link on t r e a t m e n t with p e r o x i d e s . Typical formulations for e t h y l e n e - p r o p y l e n e c o p o l y m e r (EPM) and for e t h y l e n e p r o p y l e n e - 1,4-hexadiene t e r p o l y m e r ( E P D M ) are s h o w n in Table II and III (38). N o t e w o r t h y are the good scorch resistance, excellent heat-aging p r o p e r t i e s , and hot tear strength of the E P M vulcanizate. A n interesting p r o b l e m is raised by the fact that E P D M is normally e x t e n d e d with oil, and n o e x t e n d e r oil unreactive to nitrenes is k n o w n . N e v e r t h e l e s s , good properties could be obtained using 20 parts of oil. Surprisingly, if a t h e r m a l black w a s used instead of a good reinforcing

10.

Industrial Applications

501 T A B L E III

V u l c a n i z a t i o n of E P D M with T B A F Recipe E P D M ( N o r d e l 1040) E P D M ( N o r d e l 1070) N a p h t h e n i c oil (Circosol 42 X H ) L o w a r o m a t i c oil ( F l e x o n 766) H A F b l a c k (Philblack O) T B A F (38% on H A F black)

100

100 100 20

C o m p o u n d M o o n e y viscosity ( M L - 4 at 212°F) P r o p e r t i e s after 30-min c u r e at 300°F 100% m o d u l u s (psi) 2 0 0 % m o d u l u s (psi) 3 0 0 % m o d u l u s (psi) Tensile s t r e n g t h (psi) E l o n g a t i o n (%) Shore A hardness

53 3.3

53 4.4

53 3.3

20 53 3.

58

58

59

59

280 840

320 1190

2580 395 62

3020 330 62

420 1430 2360 255 67

2

100

1570 3280 470 63

black, such as H A F , as m u c h as 40 parts of naphthenic oil could b e used without running into p r o b l e m s . Although nitrogen is a p r o d u c t of thermal decomposition of azidoform a t e s , t h e r e w a s n o evidence of blowing or porosity in the formulations described a b o v e ; resistance to blowing, in general, a p p e a r s to b e a func­ tion of c o m p o u n d viscosity, mold p r e s s u r e , and state of c u r e . A s might b e e x p e c t e d , b e c a u s e of the low gas transmission of butyl r u b b e r , blowing is m o r e of a p r o b l e m with it than with e t h y l e n e - p r o p y l e n e c o p o l y m e r s and t e r p o l y m e r s . On the plus side, T B A F gives faster cures than conventional sulfur-accelerator c o m b i n a t i o n s , and the vulcanizates are odorless and free of the b l o o m that often a p p e a r s on accelerated sulfur-cured E P D M . Although T B A F w a s given considerable trade evaluation, it w a s n e v e r m a r k e t e d , primarily for e c o n o m i c r e a s o n s . P P G Industries claimed outstanding properties for an S B R r u b b e r filled with silica and cross-linked with a bis(azidoformate) (59). T h u s a silicacontaining r u b b e r vulcanized with diethylene glycol bis(azidoformate) had tensile strength of 266 k g / c m and a w e a r index of 118, while in c o m p a r i s o n a c a r b o n black-filled r u b b e r had a tensile of 282 k g / c m and a w e a r index of 118. With sulfur vulcanization, c a r b o n fillers invariably give m u c h superior p r o p e r t i e s over silica. 2

2

502

D a v i d S. B r e s l o w

III. C r o s s - l i n k i n g of O t h e r P o l y m e r s In 1950 M o n s a n t o obtained a n u m b e r of p a t e n t s on the thermolysis of 4,4'-bis(azidosulfonyl)biphenyl for foaming and cross-linking cellulose ac­ e t a t e , alkyd r e s i n s , poly(vinylacetals), p o l y s t y r e n e , and polyethylene (40). A m e r i c a n C y a n a m i d disclosed a n u m b e r of m o n o - and polyfunctional sulfonyl azides as blowing agents for making cellular r u b b e r , and u n d o u b t e d l y the polyfunctional derivatives would also h a v e acted as cross-linking agents (41). N o n e of t h e s e w a s utilized commercially. It w a s not until H e r c u l e s investigated the chemistry of azidoformates and sul­ fonyl azides a n d s h o w e d t h e m to react as nitrenes that commercial u s e s d e v e l o p e d , in w h i c h cross-linking and blowing could b e separated (37, 4246). F r o m a practical viewpoint, the fact that p o l y p r o p y l e n e , which unlike p o l y e t h y l e n e c a n n o t be cross-linked by free-radical r e a c t i o n s , could b e modified and cross-linked by nitrenes w a s of critical i m p o r t a n c e . T h e reaction of disulfonyl azides is so efficient that less than 0 . 1 % in polypro­ p y l e n e will c h a n g e the p o l y m e r rheology to a noticeable extent (47); larger a m o u n t s cross-link the p o l y m e r (48). Since isotactic p o l y p r o p y l e n e melts at 167°C, it is not possible to react azidoformates, which h a v e 30-min halflives at 120-125°C (37), with molten p o l y p r o p y l e n e . Tosyl a z i d e , how­ e v e r , has a half-life of 33 min at 155°C, and alkanesulfonyl azides h a v e a b o u t a 10°C advantage o v e r aromatics (44). In addition, alkanesulfonyl azides contribute less color to the polymer. A n early u s e of azides w a s in the preparation of p o l y p r o p y l e n e foams (49, 50). Published p a t e n t s state that w h e n p o l y p r o p y l e n e is foamed with a blowing agent in t h e a b s e n c e of a cross-linking agent, the foam p r o d u c e d is largely o p e n celled d u e to r u p t u r e of the cell walls by the expanding g a s e s . If the p o l y p r o p y l e n e is partially cross-linked during molding with a poly (sulfonyl azide), a partially closed-cell molded article can b e pre­ p a r e d . Chlorinated aliphatic poly(sulfonyl azides) w e r e found to b e useful cross-linking agents for the manufacture of polypropylene foams (57). T h e reaction of p o l y p r o p y l e n e with smaller than cross-linking a m o u n t s of disulfonyl azides c a n lead to elastic fibers (52) and films (53). A wide variety of p o l y m e r s h a v e b e e n cross-linked b y thermal d e c o m ­ position of polyfunctional azidoformates a n d / o r sulfonyl azides: polyeth­ ylene (54), poly(vinyl chloride) (55, 56), poly(vinyl ethers) (57), acrylic p o l y m e r s (58), and p o l y c a r b o n a t e s (59). N u m e r o u s o t h e r p a t e n t s describe the simultaneous foaming and cross-linking of p o l y m e r s . F o r e x a m p l e , Phillips P e t r o l e u m has a p a t e n t on c y c l o p e n t a n e - and cyclohexanedisulfonyl azides to foam and cross-link h y d r o c a r b o n p o l y m e r s (60), and

10.

Industrial Applications

503

H e r c u l e s has p a t e n t s on foamed, cross-linked polyvinyl chloride) (67) and p o l y e s t e r (62), w h e r e the u s e of a cross-linking agent in conjunction with a foaming agent a p p e a r s to yield i m p r o v e d p r o p e r t i e s . E a s t m a n K o d a k p a t e n t e d the use of aryl azides, b o t h m o n o - and difunctional, to cross-link p o l y e t h y l e n e by heating at 170-220°C, and considered the azides to b e a s o u r c e of free radicals (63). Although certain a r o m a t i c diazides h a v e b e e n s h o w n to cross-link polypropylene (64), and p o l y p r o ­ p y l e n e is noted for its degradation by radicals, the fact that sulfur im­ p r o v e d the cross-linking s o m e w h a t is suggestive of a radical reaction (65). It s e e m s r a t h e r unlikely that sulfur would act as a dehydrogenating agent at the t e m p e r a t u r e u s e d . On the o t h e r h a n d , a two-step insertion of a triplet nitrene in a highly viscous m e d i u m has b e e n d e m o n s t r a t e d with o t h e r p o l y m e r s (7).

IV. C o u p l i n g A g e n t s It h a s b e e n well k n o w n for m a n y years that surface t r e a t m e n t of inorganic s u b s t a n c e s c a n lead to i m p r o v e d properties of filled p o l y m e r s . F o r sili­ c e o u s materials the agent of choice has b e e n a hydrolyzable silane, such as a trialkoxy derivative, containing a functional group to react with the p o l y m e r . F o r e x a m p l e , for glass-filled e p o x i e s , 3-aminopropyltriethoxysilane w o u l d b e r e a c t e d with the S i — O H groups on the glass surface and the amine g r o u p w o u l d react with the epoxide in the p o l y m e r matrix, t h u s forming c o v a l e n t b o n d s b e t w e e n the filler and the matrix (66). F o r differ­ ent p o l y m e r s , different functional groups w e r e required, and no agent w a s available to form covalent b o n d s with polyolefins. With the a d v e n t of azidoformates a n d sulfonyl a z i d e s , it b e c a m e possible to u s e o n e coupling agent for essentially all p o l y m e r s (67). T h u s a c o m p o u n d such as trimethoxysilylhexanesulfonyl azide, p r e p a r e d by chlorosulfonating trichlorosilylhexane and reacting the p r o d u c t with methanol and sodium a z i d e , w a s u s e d to treat glass cloth, which w a s then formed into a laminate with p o l y p r o p y l e n e . T h e treated glass laminate s h o w e d a flexural strength of 38,000 psi d r y , w h i c h d r o p p e d to 31,000 psi after boiling in w a t e r for 3 d a y s , while an untreated control s h o w e d a flex strength of 12,500 psi, w h i c h d r o p p e d to 8100 psi after boiling (67). Similar results w e r e obtained with o t h e r p o l y m e r s . M c F a r r e n et al. (68) s h o w e d the i m p r o v e m e n t in properties that could b e obtained with polypropylene and p o l y s t y r e n e filled with azidosilane-treated mica, Wollastonite, or clay. F o r e x a m p l e , p o l y p r o p y l e n e containing 4 0 % treated mica s h o w e d a tensile strength of

504

D a v i d S. B r e s l o w

7190 v e r s u s 4370 psi for an u n t r e a t e d control, and a flex strength of 12,800 v e r s u s 7530 psi for the control. P o l y s t y r e n e s h o w e d an increase in tensile strength from 8700 to 11,800 psi, little change in tensile m o d u l u s , but an increase in impact strength from 18 to 29 ft · lbs/in. Azidosilane-treated mica is an article of c o m m e r c e . Azidosilanes also impart excellent adhesion of p o l y m e r s to metal sur­ faces (67). T h u s steel coated with trimethoxysilylhexanesulfonyl azide and b o n d e d to polypropylene gave a lap shear strength of 2600 psi, while without azide, adhesion was negligible. Similarly, p o l y p r o p y l e n e on alu­ m i n u m gave 1600 psi, while the control gave 290 psi. C o m p a r a b l e results w e r e obtained with a silylazidoformate. Union Carbide also has p r e p a r e d silyl azides for glass t r e a t m e n t (69). In o r d e r to use a commercially available aminosilane, they investigated t w o a p p r o a c h e s . In o n e they c o n d e n s e d m-azidosulfonylbenzoyl chloride with the aminosilane (70); in the o t h e r they treated glass with an azidosulfonylcarboxylic acid aminosilane salt, and relied on the salt formation to pro­ vide the desired coupling to polymers (71).

V . Modification of P o l y m e r Surfaces A variety of p o l y m e r s h a v e had their surfaces modified by t r e a t m e n t with nitrenes. O s t e r a a s and Olsen (72), of Ashland Chemical, treated polyeth­ ylene film with a n u m b e r of nitrenes in the gas p h a s e and o b s e r v e d a change in the critical surface tension. N i t r e n e , N H , w a s generated by pyrolysis of chloramine and of hydroxylamine-O-sulfonic acid; carb e t h o x y n i t r e n e and heptylnitrene, by pyrolysis of the c o r r e s p o n d i n g az­ ides. H e p t y l n i t r e n e did not change the surface tension, u n d o u b t e d l y be­ c a u s e alkylnitrenes react by internal h y d r o g e n transfer, not by C — Η insertion (73). T h e o t h e r reagents w e r e studied in greater detail (74). T h u s b o t h c a r b e t h o x y c a r b e n e - and carbethoxynitrene-treated polyethylene had y of 39 d y n e s / c m ; the value for the untreated p o l y m e r w a s 31 d y n e s / c m . H y d r o l y s i s of t h e nitrene-treated p o l y m e r did not change y , in a g r e e m e n t with the value found for H N t r e a t m e n t , while acylation with trifluo­ roacetic a n h y d r i d e d e c r e a s e d y to 27 d y n e s / c m , in reasonable agree­ m e n t with t h e 2 2 - 2 4 d y n e s / c m obtained by converting the c a r b e t h o x y c a r ­ b e n e surface by reaction with trifluoroethanol. c

c

c

Metal surfaces w e r e r e a c t e d in a similar m a n n e r with heptyl azide, e x c e p t that the metal surface was maintained a b o v e 300°C (75). H e r e the critical surface tension varied with the metal, and it is unlikely that ni-

10.

Industrial Applications

505

t r e n e s w e r e involved. T h e p r o c e s s has b e e n p a t e n t e d for a n u m b e r of s u b s t r a t e s , although it is r a t h e r unlikely that it is practiced commercially (76). ICI has patented the use of azides to attach fluorocarbon residues to textile surfaces in o r d e r to r e n d e r fabrics soil resistant (77). Both sulfonyl azides and azidoformates w e r e c o v e r e d , (e.g., p-perfluorocaprylamidobenzenesulfonyl azide, 2-perfluorocapryloylethyl azidoformate, copoly­ m e r s of 2-azidocarbonyloxyethyl acrylate with acrylate or m e t h a c r y l a t e esters of perfluoroalcohols). S o m e w h a t similar c o m p o u n d s w e r e p a t e n t e d by A r m s t r o n g C o r k , especially for treatment of polyolefin fibers (78). Battelle patented the use of an aryl or acyl azide containing a free carboxyl group to impart polarity to a surface (79). In a totally different vein, Upjohn received a series of p a t e n t s on the u s e of sulfonyl azides to m a k e surfaces n o n t h r o m b o g e n i c (80). F o r e x a m ­ ple, a s u b s t r a t e w a s coated with nitrobenzenesulfonyl azide and irradiated with 254-nm light. T h e nitro group w a s then r e d u c e d , the resulting a m i n o g r o u p diazotized and finally coupled with a n o n t h r o m b o g e n i c material, such as l-hydroxy-8-amino-5,7-naphthalenedisulfonic acid.

VI. Tire-Cord A d h e s i v e s W o r k in this a r e a w a s initiated in an a t t e m p t to improve adhesion to poly (ethylene terephthalate) (PET) tire cord. Since it is generally believed that a covalent b o n d m u s t b e formed b e t w e e n t h e cord and t h e r u b b e r in a tire, P E T p r e s e n t s an unusual problem, as the only functional groups available are at p o l y m e r chain e n d s . T o increase the fiber tenacity, molec­ ular weights are increased, resulting in fewer chain e n d s . I n a s m u c h as nitrenes d o not rely o n chain e n d s for reaction, they would b e prime c a n d i d a t e s for this application. Although a variety of polyfunctional com­ p o u n d s s h o w e d activity, the first material m a r k e t e d w a s a bis(azidoformate) prepared from bis(hydroxyethyl)isophthalate (81a). T h e cord is coated with an emulsion of the azide and then is dried and h e a t e d to d e c o m p o s e the azidoformate. T h e m e c h a n i s m has not b e e n p r o v e d , b u t the p r o c e s s p r o b a b l y involves b o t h polymerization of the bis(azidoformate) by reaction of the nitrene with itself and simultaneous reaction with the cord surface. T h e important point is that both reactions result in a m i d e formation, for t h e next step is carried out by coating the cord with an acidified r u b b e r latex containing resorcinol and formaldehyde, the socalled R F L dip, w h i c h had b e e n developed to b o n d nylon cord to r u b b e r .

506

D a v i d S. B r e s l o w

O n drying, t h e methylolated amide and resorcinol react with e a c h o t h e r and with the r u b b e r u n s a t u r a t i o n via a Prins reaction. M o s t surprisingly, t h e s a m e s y s t e m w o r k s well on aramid fibers and results in superior p r o p e r t i e s , e v e n though it would a p p e a r that a r a m i d s should h a v e suffi­ cient amide groups not to require the azidoformate p r e t r e a t m e n t . T h e t e n d e n c y to very slow hydrolysis of azidoformate emulsions is something of a p r o b l e m , and substitution of a m o r e stable sulfonyl azide w o u l d b e desirable. T h u s , for e x a m p l e , a bis(sulfonyl azide) o n polyester tire c o r d , o v e r c o a t e d with R F L dip and vulcanized into r u b b e r , required 31 psi to t e a r t h e c o r d from t h e r u b b e r , w h e r e a s without the azide only 17 psi w a s required (81b).

VII.

Dyes

R e a c t i v e d y e s h a v e been k n o w n for m a n y y e a r s . It is not surprising, therefore, that Griffiths and c o - w o r k e r s investigated azido-substituted d y e s initially for polypropylene (82). A z o d y e s w e r e u s e d , attached to different azides 7, w h e r e X = H , ( C H ) N , or N 0 , and Y = diethylamino3

2

2

7

azido-5-triazene—NH, d i a z i d o - s - t r i a z e n e — N H , S 0 N , or N . T h e s e w e r e applied to polypropylene fiber or film from an a q u e o u s dispersion, dried, and either irradiated or heated in an air stream at 140°C until the azide group w a s completely d e c o m p o s e d . Radiation a t t a c k e d only the surface, leading to ring dyeing, but thermally, 2 6 - 5 8 % of t h e d y e was reportedly b o u n d to the p o l y m e r . This w a s s h o w n by dissolving the poly­ m e r in hot xylene, after extracting unreacted d y e with m e t h y l e n e chlo­ ride, and precipitating it with h e x a n e ; the solvent remained colorless. Unfortunately, there was no evidence that the d y e d e c o m p o s i t i o n prod­ ucts (e.g., a z o dimer, polymer, etc.) would be soluble u n d e r t h e s e condi­ t i o n s . F r o m a practical point of view, azide d e c o m p o s i t i o n w a s t o o slow at 140°C, and higher t e m p e r a t u r e s could not be used with p o l y p r o p y l e n e . 2

3

3

Griffiths and M c D a r m a i d subsequently investigated dyeing of 6,6-nylon with 2-hydroxy-5-methyl-4'-azidosulfonylazobenzene (8) (83). Below 140°C t h e major reaction w a s nucleophilic displacement of the azide g r o u p by the terminal amine group of the p o l y m e r , but at higher t e m p e r a ­ t u r e s C — Η insertion of t h e nitrene took place. T h e y therefore investi-

10.

Industrial Applications

507

gated transfer printing with a n u m b e r of azides (84). In transfer printing the d y e , from a sheet of p a p e r , w a s p r e s s e d against the fabric at an elevated t e m p e r a t u r e (e.g., 200°C). A b o u t 7 5 % of the d y e a t t a c h e d to the fiber; thus sublimation p r e c e d e d d e c o m p o s i t i o n . Aryl azide d y e s acted similarly, but here a color change took place, b e c a u s e the azide g r o u p w a s part of the c h r o m o p h o r e . T h u s 9 changed from orange to b l u e , the latter being the color of the parent a z o a m i n e [Eq. (4)]. D y e s b a s e d on sulfonyl N ~V^"~^""" = N

3

jL

+

NylonNylon

-

NH—^^-N==

9 (Blue) (4)

(Orange)

azide w e r e m o r e w a s h fast than the aryl azide d y e s , indicating a higher insertion efficiency for the former. Unfortunately, since the d y e m u s t b e volatile, colors are limited to yellow and o r a n g e ; to obtain o t h e r s h a d e s , the c h r o m o p h o r e s must b e e x t e n d e d and the d y e s b e c o m e less volatile. This lack of versatility probably p r e c l u d e s commercial u s e . A r m s t r o n g has p a t e n t e d an interesting m e t h o d of dyeing w o o d (85). Soaking w o o d in an a q u e o u s solution of 4-aminobenzene- or 3-amino-4methoxybenzenesulfonyl azide, followed by irradiation, imparted a wal­ nut color to the w o o d . Presumably a d y e is formed by reaction of the nitrene with the a m i n o g r o u p .

VIII. P o l y m e r A d d i t i v e s In m a n y applications it is desirable to b o n d an additive to a p o l y m e r to p r e v e n t its loss b y volatilization or extraction. T h u s , G o o d y e a r r e a c t e d 3,5-di-ter/-butyl-4-hydroxyphenethyl azidoformate with natural r u b b e r and d e m o n s t r a t e d that the antioxidant could not b e e x t r a c t e d (86). C a n t o r (87) carried out a similar study using the reaction p r o d u c t of /?-azidosulfonylphenyl isocyanate with 3,5-di-ter/-butyl-4-hydroxyphenyl m e t h a -

D a v i d S. B r e s l o w

508

nol or -ethylamine, which he reacted with polyethylene and polypropyl­ e n e as well as with several e l a s t o m e r s . W h e r e a c o m p a r i s o n could be m a d e , the azidoformate reaction a p p e a r e d to be m o r e efficient. In film and fiber it is very difficult, b e c a u s e of the high surface-tov o l u m e ratio, to retain additives; the p r o b l e m is especially a c u t e in fibers b e c a u s e of the n e e d to withstand laundering or dry cleaning. H e r c u l e s p a t e n t e d the u s e of azidoformates and sulfonyl azides to retain flameproofing agents, especially in p o l y e s t e r and p o l y p r o p y l e n e fibers, using c o m p o u n d s such as ß-tribromoethyl azidoformate, t e t r a b r o m o b i p h e n y l sulfonyl azide, and the like (88a).

IX. B l o w i n g A g e n t s a n d G a s G e n e r a t o r s T h e r e are several applications of azides w h e r e u s e is m a d e of their ability to liberate nitrogen. M e n t i o n has already b e e n m a d e of the u s e of azides for preparing vesicular images by p h o t o c h e m i c a l release of nitrogen gas (Section I), and of the simultaneous cross-linking and blowing of poly­ m e r s to p r e p a r e p o l y m e r foams (Section III). Blowing agents for p o l y m e r s are materials that liberate n o n t o x i c gases o n heating. T h e gas-evolution t e m p e r a t u r e needed d e p e n d s on the poly­ m e r being b l o w n . Isotactic p o l y p r o p y l e n e , for e x a m p l e , which melts at 167°C, requires a high-temperature blowing agent, w h e r e a s an elastomer c a n b e b l o w n at a m u c h lower t e m p e r a t u r e . A n early report described the formation of cellular r u b b e r by calcium azide added to the vulcanization mixture and heated at 100°C (88b). Since calcium azide is stable at these t e m p e r a t u r e s , gas evolution must involve its reaction with one of the other ingredients, p e r h a p s the vulcanization accelerator tetramethylthiuram disulfide [Eq. (5)]. General Aniline and [(CH ) NCS ] 3

2

2

2

+

2N " 3

•

2 (CH ) NCS ~ + 3

2

2

3 N

2

(5)

Film p a t e n t e d ^(TV-piperidinylazoibenzenesulfonyl azide as a blowing agent for p o l y m e r s ; p r e s u m a b l y both the azo and azide groups would liberate nitrogen (89). A m e r i c a n Cyanamid p a t e n t e d both monofunctional sulfonyl azides and sulfamoyl azides, R N S 0 N , as blowing agents for p o l y m e r s (41, 90); there are no indications that sulfamoyl azides form reactive nitrenes on heating (91). C h e v r o n R e s e a r c h p r e p a r e d polyfunc­ tional azidoformamide blowing agents, R ( — N H C O N ) _ 4 , by reacting iso­ c y a n a t e s with h y d r a z o i c acid; t h e s e materials foamed, but did not cross­ link, p o l y p r o p y l e n e and poly(vinyl chloride) (92). 2

2

3

3

2

10.

Industrial Applications

509

G a s g e n e r a t o r s , o n the other h a n d , d e m a n d different p r o p e r t i e s , the p r o b l e m h e r e being the liberation of a large a m o u n t of gas rapidly. In a passive-restraint s y s t e m to p r o t e c t automobile o c c u p a n t s from injury in a crash, a gas bag m u s t b e filled to slightly a b o v e a t m o s p h e r i c p r e s s u r e in 2 0 - 6 0 m s . T h e gas g e n e r a t o r is almost always sodium or p o t a s s i u m azide, usually in combination with an oxidizing agent and a metal halide or oxide. In o n e example described by D o w (93), the ingredients are 5 0 . 7 % sodium azide, 12.2% potassium Perchlorate, and 3 7 . 1 % m a g n e s i u m chlo­ ride, the reaction being 8 NaN

3

+ KC10

4

+ 4 MgCl

2

8 NaCl

+

12 N

2

+ KCl

+ 4 MgO

(6)

A small a m o u n t of a particulate metal (Mg, Al, etc.) m a y be a d d e d to react with any H C N , C O , or nitrogen oxide formed (93). Allied Chemicals suggested coating the particle grains with an a z i d e - c h l o r a t e or - P e r c h l o ­ rate mixture (high in oxidizer) dispersed in poly(vinyl acetate) or cellulose acetate to e n h a n c e the ignition of the gas g e n e r a t o r (94).

X. E x p l o s i v e s a n d P r o p e l l a n t s Ionic azides, such as sodium azide, are stable c o m p o u n d s , w h e r e a s cova­ lent metallic azides are shock sensitive. L e a d azide, P b ( N ) , first pre­ pared by Curtius in 1891 (95a), rapidly replaced m e r c u r y fulminate as an initiator or d e t o n a t o r b e c a u s e of its greater chemical stability (95b). It was first used by the G e r m a n A r m y in World W a r I in the form of " d e x t r i n a t e d lead a z i d e , " in which the addition of 3 % dextrin gave r o u n d e d aggregates, which w e r e less sensitive to shock; poly (vinyl alcohol) and c a r b o x y methylcellulose h a v e also been used. L e a d azide is still used in military ammunition and industrially in blasting c a p s (96). Organic azides h a v e been evaluated as alternatives to lead a z i d e , but h a v e b e e n found wanting. T h u s 2,4,6-triazido-s-triazine (cyanuric triazide) is a very efficient initiator, but is e v e n m o r e sensitive to impact and friction than m e r c u r y fulminate (96). l,3,5-Triazido-2,4,6-trinitrobenzene has high initiating efficiency and acceptable impact sensitivity, but it slowly d e c o m p o s e s at r o o m t e m p e r a t u r e (96). D o w p a t e n t e d 2-cyano3,4,5,6-tetrazidopyridine as a d e t o n a t o r (97). W o r k continues to take a d v a n t a g e of the 85 kcal p e r mole azide of energy imparted to a s y s t e m , but mostly in the area of propellants. T h e U . S . N a v y has a n u m b e r of p a t e n t s on nitro-azido c o m p o u n d s ; for e x a m ­ ple, nitramines can be chloromethylated with formaldehyde and H C l , and 3

2

510

D a v i d S. B r e s l o w 1. CH20,HC1 2. N a N 0 NNHCH CH NHNO • 0 NNCH CH NN0 3

2

2

2

CH N 2

CH N

3

(7)

2

2

3

t h e n reacted with azide [Eq. (7)] (98). T h e s e materials h a v e b e e n sug­ gested as substitutes for nitroglycerin in double-base p o w d e r , being less sensitive to shock. Dinitroalkanes can be c o n v e r t e d to nitro azides by electrolysis [Eq. (8)] (99). T h e s e are also stable ingredients for propellants. NaN3 (8)

RCH(N0.) — — * RC(N0 ) 2 I electrolysis | N z

z

3

l,9-Diazido-2,4,6,8-tetranitro-2,4,6,8-tetrazanonane (10) is claimed to b e a combustion-rate modifier in propellants and explosives; 2 0 % in H M X increased the burn rate without changing the slope of the burn-rate c u r v e (100).

N0

2

N0

2

N0

2

N0

2

10

Rockwell International has a n u m b e r of patents in this a r e a . Poly(glycidyl azide) h a s been p r e p a r e d from h y d r o x y - t e r m i n a t e d polyepichlorohydrin [Eq. (9)] (101). T h e use of this as a binder in solid propellants gives an NaNH0-(-CH„CH-0-)-H

I

HCH-OLCH-O-lrH

I

DMF

CH C1

CH N

2

2

(9)

3

improved impulse over the inert hydroxy-terminated polybutadiene nor­ mally used. T h e polymer, combined with nitrocellulose, gives a r e d u c e d flame t e m p e r a t u r e but a higher m a s s impetus than the usual double-base p o w d e r b a s e d on nitroglycerin or nitroguanidine (102). 3,3-Bis(azidom e t h y l ) o x e t a n e (11) has been p r e p a r e d from the c o r r e s p o n d i n g dichloride and polymerized to a low polymer, M 2000-3000 [Eq. (10)] (103). T h e 75-78°C softening point of the oligomer is too high to be practical. A 1: 1 c o p o l y m e r of 11 with T H F melts at - 5 ° C (104). w

10.

Industrial Applications

(N CH ) C 3

2

511

/

C

H

K

2

acid c a t .

I

2

3

> HO-(-CH CCH 0-)-H

0

2

2

(10)

11

O t h e r nitro azides h a v e b e e n claimed as energetic plasticizers for p r o ­ pellants and explosives, having b e t t e r thermal stability and lower shock sensitivity than nitroglycerin a n d , of c o u r s e , higher energy t h a n inert plasticizers. A m o n g t h e s e are fluorodinitroethoxyethyl azide (12) (105), 1,1,1,3-tetranitro-5-azido-3-azapentane (13) (105), and a z i d o m e t h y l bis(fluorodinitroethyl)amine (14) (706). o-Phthalate and adipate e s t e r s of 2,3-diazidopropanol a n d / o r 1,3-diazidoisopropanol h a v e also b e e n de­ scribed (107). (0 N) CFCH OCH CH N 2

2

2

2

2

(O^^CC^NCI^CH^

3

N0

12

2

13

N CH N[CH CF(N0 ) ] 3

2

2

2

2

2

14

XL B i o l o g i c a l A c t i v i t y A.

Pharmaceutical

Applications

Sodium azide h a s b e e n k n o w n for m a n y years to b e an antihypertensive agent, b u t it is t o o toxic to b e used (108). It would a p p e a r that almost a n y azide l o w e r s blood p r e s s u r e . T h u s ethyl azidoformate is a p o t e n t vasodi­ lator, a n d volatile azido c o m p o u n d s should be handled with a d e q u a t e ventilation (22). A n u m b e r of azides h a v e b e e n p a t e n t e d for t h e control of h y p e r t e n s i o n . A c c o r d i n g to F M C C o r p . , all arenesulfonyl azides a r e ac­ tive, but /3-styrenesulfonyl azide has b e e n p a t e n t e d for this u s e (709). 2A z i d o c y c l o h e x a n o n e oxime has also b e e n c o v e r e d (770); b o t h s h o w ac­ tivity w h e n administered orally. M e a d J o h n s o n claimed similar activity for sulfamoyl a z i d e s , 4-methylpiperazin-l-sulfonyl azide h y d r o c h l o r i d e

D a v i d S. B r e s l o w

512

N - S 0 N - HCl

CH -N

2

0

3

15

(15) being m e n t i o n e d specifically (111). It is conceivable that t h e s e com­ p o u n d s o w e their activity to a slow release of azide ion; 15 especially is hydrolytically u n s t a b l e . Squibb claimed, h o w e v e r , that certain azido-substituted proline (16, η — 1) and pipecolic acid (16, η = 2) derivatives are h y p o t e n s i v e agents d u e to their ability to inhibit angiotension-converting e n z y m e (772). I ( C

V \ n 2

R S(CH ) _ CHCO-N 2

Q

2

C

/ 2 H

CH^ C0 R 2

16

A n u m b e r of p a t e n t s claim sedative activity for certain azides. T h u s , according to S a n d o z , 2-allyl-6-azidodecahydro-4a-(3-hydroxyphenyl)-c/sisoquinoline (17) is a useful sedative (113). All the isomeric 1,4:3,6OH

Ν

H

CH CH=CH 2

2

17

dianhydro-2,5-diazido-2,5-dideoxyhexitols (18) h a v e b e e n p r e p a r e d and claimed to h a v e hypnotic activity (774), while certain azidobarbituric acids (19) are r e p o r t e d to h a v e spasmolytic and sedative action (775). Ν

3

Η I

/CH^C -

H C 2

I

\ / -CH I

C H

R=Alkyl or Ph

2

Η 18

19

10.

Industrial Applications

513

A c c o r d i n g to Topliss (116), a series of pyrimidines h a v e interesting diuretic p r o p e r t i e s . R e q u i r e d for activity are a primary amine in the 2 position, an azide in the 4 position, and a phenyl in the 6 position; t h e most active c o m p o u n d found w a s 2-amino-4-azido-5-(2-ethoxyethyl)-6phenylpyrimidine (20).

C H OCH CH 2

5

2

2

20

A z i d o a m p h e n i c o l , also k n o w n as L e u k o m y c i n A , O-(-)-threo-2-azid o a c e t a m i d o - l - p - n i t r o p h e n y l - l , 3 - p r o p a n e d i o l (21), is an antimicrobial CH0H-CH-CH.0H

I

2

NHCOCH N 2

3

21

agent (108). Azidocillin, or a-azidobenzylpenicillin (22), is an antibacte­ rial agent a n d is r e p o r t e d l y u s e d as a feed supplement to p r e v e n t mastitis in cattle (108). C00H

C H CHCONlT 6

5

22

According to H o o v e r and S t e d m a n (117), the azide g r o u p imparts im­ p r o v e d activity against gram-negative bacteria. Schering p a t e n t e d an az­ ido analog of griseofulvin, 2'-azido-7-chloro-4,6-dimethoxy-6'-methylgris2'-en-3,4'-dione (23), as an antifungal agent, w h e n administered orally, against ringworm of skin, hair, or nails (118a). T h u s , in t h e s e t h r e e c a s e s , the azide group modifies the k n o w n activities of the parent c o m p o u n d s , chloramphenical (21, substituting C H C 1 for C H N ) , benzylpenicillin, 2

2

3

514

D a v i d S. B r e s l o w

0

23

and griseofulvin. Ύή-η- or isobutyltin azide, as well as the bis(dialkylazidotin) oxide, are reportedly m o r e active as fungicides and bactericides than o t h e r tin c o m p o u n d s , especially against gram-negative bacteria (118b). N o n e of t h e s e c o m p o u n d s is listed in the 1980 edition of the U.S. Pharmacopeia/National Formulary (119).

B. Herbicides

and

Pesticides

In 1968, P P G Industries p a t e n t e d the use of sodium and p o t a s s i u m azides as b r o a d - s p e c t r u m herbicides (720). Depending on the application level, they could act to kill all g r o w t h , p r e v e n t seed germination, regulate g r o w t h , p r e v e n t t o b a c c o s u c k e r s , thin fruit, and the like. Since soil micro­ organisms c o n v e r t the azide into available nitrogen, fields could b e planted a short time after t r e a t m e n t , toxic residues d i s a p p e a r e d , and at high d o s e s the material acted as a fertilizer (although it is highly doubtful that the last could be e c o n o m i c at p r e s e n t azide prices). T h e y later recom­ m e n d e d azide u s e against Florida beggarweed in p e a n u t s (727) and claimed that the addition of certain metal salts d e c r e a s e d phytotoxicity (122). A n u m b e r of organic azides h a v e also b e e n claimed to be useful herbi­ cides. T h u s , D e g u s s a p a t e n t e d a series of azido-s-triazines (24, R = a lower alkyl group) as selective w e e d killers and defoliants (123). CibaGeigy p a t e n t e d similar c o m p o u n d s containing a cyclopropyl group (25)

V 24

25

26

3

10.

Industrial Applications

515

(124) or a c a r b a m a t e (26) (125) as a pre- or p o s t e m e r g e n t herbicide for killing broadleaf plants. E t h y l Corporation p a t e n t e d tri-ft-butyltin azide as a defoliant (126). Shell Oil patented a sulfonyl azide as a herbicide (27, R = alkyl, cycloalkyl, or allyl) (727), and Eli Lilly p a t e n t e d an aryl azide (28) as a p r e m e r g e n t herbicide (726").

(CH ) N 3

2

27

28

S o m e of t h e s e azides are also pesticides. T h u s sodium and p o t a s s i u m azides control Pithium spp. and Sclerotium s p p . , fungi that attack bentgrass, s o y b e a n s , and p e a n u t s , as well as n e m a t o d e s (722, 729). A z i d e 28 is r e p o r t e d to b e active against Plasmopara viticola, which c a u s e s d o w n y mildew on g r a p e s (128). C o m p o u n d s 24 and 25, as well as similar o n e s , are active against flies and m o s q u i t o s in their larva or p u p a stages, p r e ­ venting m e t a m o r p h o s i s (750). Z o e c o n p a t e n t e d a n u m b e r of azides that show j u v e n i l e h o r m o n e activity (29 and 30) (757). ( C H ) CCOCH CH CHCH CH=CHC«CHC00CH 3

2

2

N

3

2

2

CH

CH

3

3

3

( C H ) C ( C H ) CHCH CH»CHC=CHCOOCH 3

2

2

N

3

2

CH

3

29

Chevron (132).

3

30

patented

trichloromethylazidoamides

RNHCHCC1 N

CH

3

3

3

3

31 as

nematocides

(CH ) CCCH N 3

3

2

3

N0C0NHCH

3

31 R-PhCO, P h S 0 , C H O C O , etc. 2

2

5

32

D i a m o n d S h a m r o c k reported azido-oxime c a r b a m a t e s 32 to be active against insects, mites, and n e m a t o d e s (755). D u P o n t claimed that certain azido esters (33) are active against south­ ern a r m y w o r m larvae, houseflies, and boll weevils (134). A l m o s t identi-

516

D a v i d S. B r e s l o w

cal c o m p o u n d s h a v e been described in a E u r o p e a n patent application by Ciba-Geigy (135). Sodium azide is claimed to b e a unique fungicide for the p r e s e r v a t i o n of wine (95b).

XII. P o l y m e r i z a t i o n I n i t i a t o r s D u p o n t p a t e n t e d sodium azide plus an oxidizing agent ( M n 0 ~ , C I O " , C e , etc.) as a l o w - t e m p e r a t u r e initiator for the emulsion polymerization of acrylonitrile (136a). T h e r e h a v e b e e n a n u m b e r of r e p o r t s of sulfonyl azides as initiators of free-radical polymerizations (18, 136b). Activity is usually low, and the m e c h a n i s m of initiation is o b s c u r e (18, p . 272). H o w e v e r , reasonably active initiators for t h e emulsion polymerization of conjugated dienes h a v e b e e n r e p o r t e d to b e formed from what a p p e a r to b e r e d o x s y s t e m s — sulfonyl or p h o s p h o n y l azides in the p r e s e n c e of ferrous sulfate plus a chelating agent (137). Since the polymerizations w e r e carried out at 50°C, nitrenes could not be involved. At this t e m p e r a t u r e , h o w e v e r , the 1,3dipolar cycloaddition of sulfonyl azides with double b o n d s could be in­ volved in the initiation (18, p . 291), and it is r e a s o n a b l e that o n e of the intermediates p o s t u l a t e d by A b r a m o v i t c h (138) to b e formed in the reac­ tion could set u p a r e d o x s y s t e m with ferrous ion ( S c h e m e 1). 4

4 +

\ RS0 N„ + 2

/

3

/ C=C

o

I —>

I

—C

\

I

^N

I C—

>

C—

I v

I

—C I

,N

RS0 N" o

I

N+

RSO' "2 I

—C

I

RS0 N 2

I

I

C— N£

+

2 +

Fe

>

I

—C

ι

RS0 N 2

Scheme 1

I

C—

+

3+

Fe

+ N 2 0

10.

Industrial Applications

517

XIII. M i s c e l l a n e o u s A p p l i c a t i o n s M a s o n listed several applications for inorganic azides (95b). B a r i u m and strontium azides h a v e b e e n u s e d as " g e t t e r s " in the p r e p a r a t i o n of elec­ tric-discharge t u b e s . Salts modified with sodium azide h a v e b e e n used to purify m o l t e n aluminum and a l u m i n u m - s i l i c o n alloys. Azide salts are effective in preventing the rusting of iron. Sodium azide at p H 9 - 1 2 p r e v e n t s coagulation of latex stored in metal c o n t a i n e r s . Silver a z i d e , especially with a d d e d oxalic acid, increases the photosensitivity of p h o t o ­ graphic silver b r o m i d e emulsions. Gulf R e s e a r c h and D e v e l o p m e n t claimed that aryl azides i m p r o v e the c e t a n e n u m b e r of diesel fuel (139). Rockwell International claimed that certain azides [nitroalkyl and nitrato-alkyl azides, glycidyl a z i d e , and 3,3bis(azidomethyl)oxetane m o n o m e r s and polymers] i m p r o v e the t h e r m a l efficiency of b o t h gasoline and diesel fuel (140). F M C p a t e n t e d a r o m a t i c sulfonyl azides as p e r o x y g e n activators for c o m p o u n d s such as sodium p e r b o r a t e (141). M I T I d e s c r i b e d the u s e of water-soluble aryl azides to immobilize en­ z y m e s on a solid support (142). A p o l y m e r is treated with the e n z y m e and sodium 4,4'-diazidostilbene-2,2'-disulfonate; irradiation then cross-links the p o l y m e r a n d immobilizes the e n z y m e . Alternatively, poly (vinyl alco­ hol), partially esterified with /?-azidobenzoic acid, can b e u s e d .

References 1. G. A . D e l z e n n e , in ' ' E n c y c l o p e d i a of P o l y m e r S c i e n c e a n d T e c h n o l o g y , " S u p p l . 1, p . 4 0 1 . Wiley ( l n t e r s c i e n c e ) , N e w Y o r k , 1976. 2. A . R e i s e r a n d Η . M . W a g n e r in " T h e C h e m i s t r y of the A z i d o G r o u p " ( S . P a t a i , e d . ) , C h a p t . 8. Wiley ( l n t e r s c i e n c e ) , N e w Y o r k , 1971. 3. J. S. S w e n t o n , Tetrahedron Lett., 3421 (1968). 4. J. J. S a g u r a a n d J. A . V a n Allan, U . S . P a t . 2,940,853 (1960) (to E a s t m a n K o d a k ) . 5. T. T s u n o d a , T . Y a m a o k a , a n d G. N a g a m a t s u , Photogr. Sei. Eng. 1 7 , 390 (1973). 6. M . A. G o l u b in " P o l y m e r C h e m i s t r y of S y n t h e t i c E l a s t o m e r s " (J. P. K e n n e d y a n d E . G. M . T o r n q v i s t , e d s . ) , p . 940 ff. Wiley ( l n t e r s c i e n c e ) , N e w Y o r k , 1969. 7. A . R e i s e r , L . J. L e y s h o n , a n d L . J o h n s t o n e , Trans. Faraday Soc. 6 7 , 2389 (1971). 8. L . S. Efros and T . A . Y u r r e , Polym. Sei. USSR (Engl. Transl.) 12, 2505 (1970). 9. L . H o r n e r , A . C h r i s t m a n n , a n d A. G r o s s , Chem. Ber. 9 6 , 399 (1963). 10. S. H . Merrill a n d C . C . U n r u h , Appl. Polym. Sei. 7 , 273 (1963). 11. U . L . L a r i d o n , G . A . D e l z e n n e , a n d Η . K . P e e t e r s , U . S . P a t . 3,721,566 (1973) (to AgfaGevaert). 12. G. A . D e l z e n n e a n d U . L a r i d o n , J. Polym. Sei. Part C 22, 1149 (1969).

518

D a v i d S. B r e s l o w

13. A . R e i s e r , F . W . W i l l e t s , G. C. T e r r y , V . Williams, a n d R. M a r l e y , Trans. Faraday Soc. 6 4 , 3265 (1968). 14. A . R e i s e r a n d L . J. L e y s h o n , / . Am. Chem. Soc. 9 3 , 4051 (1971). 15. R . H u i s g e n , Angew. Chem. Int. Ed. Engl. 2 , 578 (1963). 16. M . T s u d a , A . Y a b e , a n d H . T a k a n a s h i , Bull. Soc. Photogr. Sei. Technol. Jpn., N o . 2 3 , 12 (1973) [Chem. Abstr. 8 3 , 59671 (1975)]. 17. M . T s u d a , S. O i k a w a , W . K a n a i , K . H a s h i m o t o , A . Y o k o t a , K . N u i n o , I. Hijikata, A . U e h a r a , a n d H . N a k a n e , / . Vac. Sei. Technol. 19, 1351 (1981). 18. D . S. B r e s l o w in " N i t r e n e s " ( W . L w o w s k i , e d . ) , C h a p t . 8. Wiley ( I n t e r s c i e n c e ) , N e w Y o r k , 1970. 19. H . H o l t s c h m i d t a n d G. O e r t e l , Angew. Macromol. Chem. 9, 1 (1969). 20. J. D a n h o u s e r a n d W . P e l t z , U . S . P a t . 3,462,268 (1969) (to A g f a - G e v a e r t ) . 2 1 . U . L . L a r i d o n , G. A . D e l z e n n e , H . M ä d e r , H . U l r i c h , a n d B . Seidel, U . S . P a t s . 3,467,518 (1969) a n d 4,065,524 (1977) (to A g f a - G e v a e r t ) . 22. D . S. B r e s l o w , u n p u b l i s h e d o b s e r v a t i o n . 23. G . Μ . P e t e r s , J r . , F . Α . S t u b e r , a n d H . U l r i c h , U . S . P a t . 3,947,337 (1976) (to U p j o h n ) . 24. F . A . S t u b e r , H . U l r i c h , D . V . R a o , a n d A . A . R. Sayigh, Photogr. Sei. Eng. 17, 446 (1973). 25. B . Seidel, H . M ä d e r , J. D a n h o u s e r , a n d H . B a r t l , U . S . P a t . 3,467,523 (1969) (to AgfaGevaert). 26. Η . W . G i b s o n , F . C . Bailey, and J. Y. C. C h u , J. Polym. Sei. Chem. Ed. 17, 777 (1979). 27. a. M . T s u d a , S. O i k a w a , W . K a n a i , A . Y o k o t a , I. Hijikata, A . U e h a r a , a n d H . N a k a n e , J. Vac. Sei. Technol. 19, 259 (1981); b . T . M a t s u z a w a , K . D o u t a , T. I w a y a n a g i , a n d H . Y a n a g i s a w a , E u r . P a t . A p p l . E P 40,535 (1980) (to H i t a c h i ) [Chem. Abstr. 96, 78613 (1982)]. 28. T . T o y a m a a n d M . I w a s a k i , U . S . P a t . 4,191,573 (1980) (to Fuji P h o t o Film). 29. H . U l r i c h , F . A. S t u b e r , and A. A . R. Sayigh, Polym. News 1(8,9,10), 8 (1973). 30. H . U l r i c h , F . A . S t u b e r , G. M . P e t e r s , J r . , a n d A . A. R. S a y i g h , J. Polym. Sei. Chem. Ed. 14, 565 (1976). 3 1 . J. K o s a r , " L i g h t - S e n s i t i v e S y s t e m s , " Wiley, N e w Y o r k , 1965. 32. B . Singh, U . S . P a t s . 3,844,793 (1974) a n d 3,933,497 (1976) (to A m e r i c a n C y a n a m i d ) . 33. A . S. M a r s h a l l , W . J. P r i e s t , a n d J. A . V a n Allan, U . S . P a t . 3,519,425 (1970) (to Eastman Kodak). 34. W . J. P r i e s t a n d A . S. M a r s h a l l , U . S . P a t s . 3,532,500 (1970) a n d 3,646,032 (1972) (to Eastman Kodak). 35. N . H a y a s h i , M . A k a g i , K . M i u r a , a n d Y . O d a k a , U . S . P a t . 4,332,874 (1982) (to Hi­ tachi). 36. Τ . J. P r o s s e r , Α . F . M a r c a n t o n i o , C. A . G e n g e , a n d D . S. B r e s l o w , Tetrahedron Lett., 2483 (1964). 37. D . S. B r e s l o w , T . J. P r o s s e r , C. A . G e n g e , a n d A . F . M a r c a n t o n i o , J. Am. Chem. Soc. 89, 2384 (1967). 38. D . S. B r e s l o w , W . D . Willis, a n d L . O . A m b e r g , Rubber Chem. Technol. 4 3 , 605 (1970). 39. J. C r e a s y , G e r . P a t . 2,165,198 (1972) (to P P G I n d u s t r i e s ) [Chem. Abstr. 77, 165809 (1972)]. 40. J. B . O t t , U . S . P a t s . 2,518,249 (1950) a n d 2,532,240-243 (1950) (to M o n s a n t o ) . 4 1 . F . H . A d a m s , U . S . P a t . 2,830,029 (1958) (to A m e r i c a n C y a n a m i d ) . 42. D . S. B r e s l o w a n d Ε . I. E d w a r d s , Tetrahedron Lett., 2123 (1967). 4 3 . D . S. B r e s l o w , Ε . I. E d w a r d s , R. L e o n e , a n d P . v o n R. S c h l e y e r , J. Am. Chem. Soc. 90, 7097 (1968).

10.

Industrial Applications

519

44. D . S. B r e s l o w , M . F . S l o a n , N . R. N e w b u r g , a n d W . B . R e n f r o w , / . Am. Chem. Soc. 9 1 , 2273 (1969). 4 5 . D . S. B r e s l o w a n d Ε . I. E d w a r d s , Tetrahedron Lett., 2041 (1972). 46. D . S. B r e s l o w , Ε . I. E d w a r d s , E . C . L i n s a y , a n d H . O m u r a , J. Am. Chem. Soc. 98, 4268 (1976). 47. W . W . C o x , U . S . P a t . 3,336,268 (1967) (to H e r c u l e s ) . 48. D . S. B r e s l o w a n d Η . M . Spurlin, U . S . P a t . 3,058,944 (1962) (to H e r c u l e s ) . 49. D . A . P a l m e r , U . S . P a t . 3,250,730 (1966) (to H e r c u l e s ) . 50. F . C. B u h l a n d G . B . Feild, U . S . P a t . 3,250,731 (1966); G. B . Feild a n d P . L . J o h n ­ s t o n e , U . S . P a t . 3,298,975 (1967) (to H e r c u l e s ) . 5 1 . N . R. N e w b e r g , U . S . P a t . 3,287,376 (1966) (to H e r c u l e s ) . 52. G . C . O p p e n l a n d e r , U . S . P a t . 3,485,906 (1969) (to H e r c u l e s ) . 5 3 . G. C. O p p e n l a n d e r , U . S . P a t . 3,530,108 (1970) (to H e r c u l e s ) . 54. D . S. B r e s l o w a n d Η . M . Spurlin, U . S . P a t s . 3,203,936 a n d 3,203,937 (1965) (to H e r c u ­ les). 55. A . E . R o b i n s o n , U . S . P a t . 3,261,785 (1966) (to H e r c u l e s ) . 56. D . S. B r e s l o w , U . S . P a t . 3,261,786 (1966) (to H e r c u l e s ) . 57. D . S. B r e s l o w , U . S . P a t . 3,058,957 (1962) (to H e r c u l e s ) . 58. D . S. B r e s l o w a n d F . E . P i e c h , U . S . P a t . 3,322,733 (1967) (to H e r c u l e s ) . 59. Ε . E . B o s t i c k a n d A . R. Gilbert, U . S . P a t s . 3,583,939 (1971) a n d 3,770,696 (1973) (to General Electric). 60. H . W . B o s t a n d J. E . M a h a n , U . S . P a t . 3,282,864 (1966) (to Phillips P e t r o l e u m ) . 6 1 . G . B . Feild a n d J. R. L e w i s , U . S . P a t . 3,211,677 (1965) (to H e r c u l e s ) . 62. A . E . R o b i n s o n , U . S . P a t . 3,211,678 (1965) (to H e r c u l e s ) . 6 3 . G. C. N e w l a n d a n d J. A . V a n Allan, U . S . P a t . 3,075,950 (1963) (to E a s t m a n K o d a k ) . 64. D . S. B r e s l o w a n d A . F . M a r c a n t o n i o , U . S . P a t . 3,297,674 (1967) (to H e r c u l e s ) . 65. D . S. B r e s l o w a n d A . F . M a r c a n t o n i o , U . S . P a t . 3,297,661 (1967) (to H e r c u l e s ) . 66. E . P. P l u e d d e m a n n , H . A . C l a r k , L . E . N e l s o n , a n d K . R. Hoffman, Mod. Plast. 3 9 , 135 ( A u g , 1962). 67. J. B . T h o m s o n , U . S . P a t s . 3,697,551 (1972), 3,705,911 (1972), 3,706,592 (1972), 3,715,371 (1973), a n d 3,813, 351 (1974) (to H e r c u l e s ) . 68. G . A . M c F a r r e n , T . F . S a n d e r s o n , a n d F . G . S c h a p p e l l , Soc. Plast. Eng. Tech. Pap. 2 2 , 19 (1976). 69. P . J. O r e n s k i a n d J. G. M a r s d e n , Soc. Plast. Eng. Tech. Pap. 2 2 , 68 (1976). 70. J. G. M a r s d e n a n d P . J. O r e n s k i , U . S . P a t . 4,038,456 (1977) (to U n i o n C a r b i d e ) . 7 1 . J. G. M a r s d e n a n d P . J. O r e n s k i , U . S . P a t . 4,055,701 (1977) (to U n i o n C a r b i d e ) . 72. A . J. O s t e r a a s a n d D . A . O l s e n , Nature {London) 2 2 1 , 1140 (1969). 7 3 . F . D . L e w i s a n d W . H . S a u n d e r s , Jr. in " N i t r e n e s " ( W . L w o w s k i , e d . ) , p . 56. Wiley ( l n t e r s c i e n c e ) , N e w Y o r k , 1970. 74. A . J. O s t e r a a s a n d D . A . O l s e n , J. Appl. Polym. Sei. 13, 1537 (1969). 75. D . A. Olsen a n d A . J. O s t e r h a a s , J. Colloid Interface Sei. 32, 12 (1970). 76. D . A . Olsen and A . J. O s t e r h a a s , U . S . P a t . 3,666,536 (1972) (to A s h l a n d C h e m i c a l ) . 77. J. B u c k l e y , R. B u d z i a r e k , A . J. N i c h o l a s , a n d E . J. V i c k e r s , U . S . P a t . 3,997,571 (1976) (to I C I ) . 78. J. E . H e r w e h , U . S . P a t . 4,099,910 (1978) (to A r m s t r o n g C o r k ) . 79. R . R e i n e r , U . S . P a t . 4,309,453 (1982) (to Battelle). 80. D . L e d n i c e r a n d Ε . E . N i s h i z a w a , U . S . P a t s . 3,888,833 (1975), 3,954,583 (1976), a n d 3,975,371 (1976) (to U p j o h n ) . 8 1 . a. J. N . H a y n e s , U . S . P a t s . 3,686,231 (1972), 3,814,657 (1974), 3,914,262 (1975), a n d 3,946,051 (1976) (to H e r c u l e s ) ; b . D . S. B r e s l o w , U . S . P a t . 3,616,199 (1971) (to H e r c u ­ les).

520

D a v i d S. B r e s l o w

82. J. Griffiths, M . F a g b u l e , a n d R . I. M c D a i r m a i d , Textilveredlung 7, 807 (1972) [Chem. Abstr. 78, 45020 (1973)]. 83. J. Griffiths and R. I. M c D a r m a i d , J. Soc. Dyers Colour. 9 3 , 455 (1977). 84. J. Griffiths and R. I. M c D a r m a i d , J. Soc. Dyers Colour. 9 4 , 65 (1978). 85. C . E . H o y l e a n d R. S. L e n o x , U . S . P a t . 4,322,211 (1982) (to A r m s t r o n g W o r l d I n d u s ­ tries). 86. R. D . P o r t e r a n d S. W . W a i s b r o t , U . S . P a t . 3,911,131 (1976) (to G o o d y e a r Tire a n d Rubber). 87. S. E . C a n t o r , Polym. Prepr. 18(1), 471 (1977); idem, U . S . P a t . 4,031,068 (1977) (to Uniroyal). 88. a. J. C . W . Chien a n d F . G. S c h a p p e l l , U . S . P a t s . 3,957,835 (1976) and 4,009,294 (1977) (to H e r c u l e s ) ; b . J. T a n a k a and K . Y a s u d a , Rep. Osaka Prefect. Ind. Res. Inst. 4, 32 (1952) [Chem. Abstr. 46, 11743 (1952)]. 89. W . H . v o n G l a h n a n d B . R u d n e r , U . S . P a t . 2,828,299 (1958) (to G e n e r a l Aniline a n d Film). 90. W . B . H a r d y a n d F . H . A d a m s , U . S . P a t s . 2,863,866 (1958) a n d 2,912,391 (1959) (to American Cyanamid). 9 1 . R . A . A b r a m o v i t c h a n d K . M i y a s h i t a , J. Chem. Soc. Perkin Trans. 1, 2413 (1975). 92. S. S u s u k i , U . S . P a t s . 3,526,644 a n d 3,547,843 (1970) (to C h e v r o n R e s e a r c h ) . 9 3 . Τ . E . D e r g a z a r i a n a n d G. A. L a n e , U . S . P a t . 3,936,330 (1976) (to D o w C h e m i c a l ) . 94. E . F . G a r n e r a n d Β . K . H a m i l t o n , U . S . P a t . 4,244,758 (1981) (to Allied C h e m i c a l ) . 9 5 . a. T . C u r t i u s , Ber. 24, 3341 (1891); b . K . G. M a s o n in " M e l l o r ' s C o m p r e h e n s i v e T r e a t i s e o n I n o r g a n i c and T h e o r e t i c a l C h e m i s t r y " (Vol. 8), S u p p l . 2N (Part II), p p . 5 0 5 1 . W i l e y , N e w Y o r k , 1967. 96. ' ' K i r k - O t h m e r E n c y c l o p e d i a of C h e m i c a l T e c h n o l o g y , " 2nd e d . , V o l . 8, p . 584, 1965; 3rd e d . , V o l . 9, p . 570, 1980. 97. C . E . P a n n e l l , U . S . P a t s . 3,773,774 (1973) a n d 3,883,542 (1975) (to D o w C h e m i c a l ) . 9 8 . R. R o s h e r , U . S . P a t s . 3,873,579 a n d 3,883,374 (1975) (to U . S . S e c r e t a r y of t h e N a v y ) . 99. C . M . W r i g h t , U . S . P a t . 3,883,377 (1975) (to U . S . S e c r e t a r y of t h e N a v y ) . 100. R. A . H e n r y a n d W . P . N o r r i s , U . S . P a t . A p p l . U S 256,230 ( N o v . 20, 1981) (to U . S . S e c r e t a r y of t h e N a v y ) [Chem. Abstr. 96, 165043 (1982)]. 101. Μ . B . F r a n k e l a n d J. E . F l a n a g a n , U . S . P a t . 4,268,450 (1981) (to R o c k w e l l I n t e r n a ­ tional). 102. J. E . F l a n a g a n a n d J. C. G r a y , U . S . P a t . 4,288,262 (1981) (to R o c k w e l l I n t e r n a t i o n a l ) . 103. Μ . B . F r a n k e l , Ε . R. W i l s o n , D . O . W o o l e r y I I , C. L . H a m m e r m e s h , a n d C . M c A r t h u r , CPIA Publ. 340 (1981) [Chem. Asbtr. 97, 74986 (1982)]. 104. Μ . B . F r a n k e l , Ε . R. W i l s o n , D . O . W o o l e r y I I , C. L . H a m m e r m e s h , a n d C. M c A r t h u r , Gov. Rep. Announce. Index (U.S.) 8 2 , 2156 (1982) [Chem. Abstr. 97, 110490 (1982)]. 105. J. E . F l a n a g a n , Μ . B . F r a n k e l , a n d E . F . W i t u c k i , U . S . P a t . 4,141,910 (1979) (to Rockwell International). 106. Μ . B . F r a n k e l , U . S . P a t . A p p l . U S 350,494 (Sept. 10, 1982) (to U . S . S e c r e t a r y of t h e A i r F o r c e ) [Chem Abstr. 97, 200326 (1982)]. 107. Μ . B . F r a n k e l , Ε . R. W i l s o n , a n d J. E . F l a n a g a n , U . S . P a t . A p p l . U S 283,708 (Jan. 15, 1982) (to U . S . S e c r e t a r y of t h e N a v y ) [Chem. Abstr. 96, 165045 (1982)]. 108. " M e r c k I n d e x , " 9th e d . M e r c k & C o . , R a h w a y , N e w J e r s e y , 1976. 109. T . Weil a n d H . S t a n g e , U . S . P a t . 3,471,616 (1969) (to F M C ) . 110. T . Weil a n d H . S t a n g e , U . S . P a t s . 3,376,319 (1968) a n d 3,424,843 (1969) (to F M C ) . 111. W . L . M a t i e r a n d W . J. C o m e r , U . S . P a t s . 3,723,627 (1973) a n d 3,789,120 (1974) (to Mead Johnson).

10.

Industrial Applications

521

112. J. K r a p c h o , P. C . W a d e , E . W . Pertrillo, J r . , a n d F . L . W e i s e n b o r n , E u r . P a t . A p p l . E P 42,639 ( D e c . 30, 1981) (to S q u i b b ) [Chem. Abstr. 96, 181622 (1982)]. 113. P . Pfäffli a n d H . H a u t h , U . S . P a t . 4,301,290 (1981) (to S a n d o z ) . 114. J. K u s z m a n n , G . M e d g y e s , F . A n d r a s y , a n d P . B e r z s e n y i , U . S . P a t . 4,332,818 (1982) (to E g y t G y o g y s z e r v e g y e s z e t i G y ä r ) . 115. G . T o t h , F . C s e n d e , S. M a k l e i t , a n d G. S o m o g y i , H u n g . T e l y e s H U 19,767 (April 2 8 , 1981) (to Alkaloids V e g y e s z e t i G y ä r ) [Chem. Abstr. 96, 6750 (1982)]. 116. J. G. T o p l i s s in " M e d i c i n a l C h e m i s t r y " (A. B u r g e r , e d . ) , 3rd e d . , p . 1011. Wiley ( l n t e r s c i e n c e ) , N e w Y o r k , 1970. 117. J. R. E . H o o v e r a n d R . J. S t e d m a n in " M e d i c i n a l C h e m i s t r y " (A. B u r g e r , e d . ) , 3rd e d . , p . 390. Wiley ( l n t e r s c i e n c e ) , N e w Y o r k , 1970. 118. a. L . S h a p i r o a n d A . K . G a n g u l y , U . S . P a t . 3,816,472 (1974) (to S c h e r i n g ) ; b . H . P l u m a n d U . S c h r o e d e r , U . S . P a t . 4,112,084 (1978) (to S c h e r i n g ) . 119. " T h e U n i t e d S t a t e s P h a r m a c o p e i a , " 20th r e v . e d . ; " T h e N a t i o n a l F o r m u l a r y , " 15th e d . U n i t e d S t a t e s P h a r m a c o p e i a C o n v e n t i o n , R o c k v i l l e , M a r y l a n d , J u l y 1980. 120. W . C. M c C o n n e l l a n d H . W . R a h n , U . S . P a t s . 3,376,125-7 (1968) (to P P G I n d u s t r i e s ) . 121. C. M . C h a n d l e r , U . S . P a t . 3,874,868 (1975) (to P P G I n d u s t r i e s ) . 122. W . C. M c C o n n e l l , U . S. P a t . 4,132,780 (1979) (to P P G I n d u s t r i e s ) . 123. H . S c h u l t z a n d W . S c h w a r z e , U . S . P a t . 3,326,913 (1967) (to D e g u s s a ) . 124. D . B e r r e r a n d C . V o g e l , U . S . P a t s . 3,583,987 (1971) a n d 3,723,088 (1973); D . B e r r e r , M . K u h n e , a n d C . V o g e l , U . S . P a t . 3,830,810 (1974) (to Ciba-Geigy). 125. D . B e r r e r , U . S . P a t . 4,007,032 (1977) (to Ciba-Geigy). 126. L . P l o n s k e r a n d N . R . W r i g h t , U . S . P a t . 3,552,945 (1971) (to E t h y l C o r p . ) . 127. Κ . H . G . Pilgrim, U . S . P a t . 3,692,805 (1972) (to Shell Oil). 128. J. R. B e c k , U . S . P a t . 3,948,957 (1976) (to Eli Lilly). 129. W . C. M c C o n n e l l , U . S . P a t . 3,812,254 (1974) (to P P G I n d u s t r i e s ) . 130. A . H e r z o g , U . S . Pat. 3,856,950 (1974); A . H e r z o g a n d H . U . B r e c h b ü h l e r , U . S . P a t s . 3,853,868 (1974) a n d 3,985,877 (1976); H . U . B r e c h b ü h l e r , R. B o s s h a r d , a n d D . B e r r e r , U . S . P a t . 4,000,272 (1976) (to C i b a - G e i g y ) . 131. C . A . H e n r i c k a n d J. B . Siddall, U . S . P a t . 3,832,361 (1974); C . A . H e n r i c k , U . S . P a t . 3,864,364 (1975) (to Z o e c o n ) . 132. M . S. Singer, U . S . P a t s . 3,700,699 (1972), 3,752,890 (1973), a n d 3,796,729 (1974) (to Chevron Research). 133. T. A . M a g e e , U . S . P a t . 3,932,471 (1976) (to D i a m o n d S h a m r o c k ) . 134. J. B . A d a m s , J r . , U . S . Pat. 4,311,696 (1982) (to D u P o n t ) . 135. H . F i s c h e r , R. C . T h u m m e l , a n d R. W e h r l i , E u r . P a t . A p p l . 29,002 A l ( M a y 20, 1981) (to Ciba-Geigy) [Chem. Abstr. 96, 68614 (1982)]. 136. a. E . G . H o w a r d , J r . , U . S . P a t . 2,594,560 (1952) (to D u P o n t ) ; b . M . I m o t o a n d T . N a k a y a , J. Macromol. Sei. Rev. Macromol. Chem. C 7 , 40 (1972). 137. J. E . B u r l e i g h a n d C . A . U r a n e c k , U . S . P a t . 3,301,841 (1967) (to Phillips P e t r o l e u m ) . 138. R. A . A b r a m o v i t c h , G. A . K n a u s , Μ . Pavlin, a n d W . D . H o l c o m b , J. Chem. Soc. Perkin Trans. I, 2169 (1974); R. A . A b r a m o v i t c h , M . O r t i z , a n d S. P . M c M a n u s , J. Org. Chem. 46, 330 (1981). 139. R. J. H a r t l e a n d G. M . S i n g e r m a n , U . S . P a t . 4,280,819 (1981) (to Gulf R e s e a r c h a n d Development). 140. Μ . B . F r a n k e l a n d J. E . F l a n a g a n , U . S . P a t . 4,303,414 (1981) (to R o c k w e l l I n t e r n a ­ tional). 141. F . R. S c h o l a r a n d J. H . B l u m b e r g , U . S . P a t . 4,120,652 (1978) (to F M C ) . 142. S. M i y a i r i , H . T a n a k a , A . Y a b e , a n d K . H o n d a , U . S . P a t . 4,160,698 (1979) (to A g e n c y of I n d u s t r i a l S c i e n c e a n d T e c h n o l o g y , M I T I ) .