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Study of the polyaddition reaction of 1,3-bis-(dimethylsilyl) tetramethylcyclodisilazane to unsaturated compounds
Polymer Science U.S.S.R. Vol. 21, pp. 996-1003. (~) Pergamon Press T,td. 1980. Printed in Poland
0032-3950/79/0401-0996507.50/0
STUDY OF THE POLYADDITION REACTION OF 1,3-BIS-(DIMETHYLSILYL) TETRAMETHYLCYCLODISILAZANE TO UNSATURATED COMPOUNDS* K. A. ANImlAN0V (dee.), M. I. SHKOL'NIK, V. M. K01"rL0V, L. M. KHANAlVASHVILI and P. L. PRIKHOD'K0 M. V. Lomonosov I n s ti tu te of Fine Chemical Technology, Moscow
(Received 6 April 1978) A study was made of p'olyaddition of 1,3-bis-(dimethylsilyl)tctramethylcyclodisilazane to unsaturated organic and organosilicon compounds. I t was shown t h a t 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane is highly reactive, but one of t h e reaction conditions is the formation of an intermediate catalyst complex. A study was made of thermal oxidizing breakdo~ua of polymers synthesized and it was shown t h a t the addition to the polymer chain of a cyclodisilazane fragment increases resistance to thermal oxidizing breakdown.
TH~l~E are several studies in the literature, which describe the addition of hydride organosilazanes containing a hydrogen atom and organic radicals at the nitrogen atom to unsaturated compounds [1-4]. I t was found that in contrast to organosiloxanes, organosilazanes are characterized by several properties due to structure. The addition of hydride organosilazanes containing hydrogen at the nitrogen atom to unsaturated compounds is accompanied by a seconadary reaction o f dehydrocondensation [l, 3] and on replacing hydrogen at the nitrogen atom in 1,3-dihydrotetramethyldisilazane by an organic radical a strong reduction is observed in the reactivity of the second S i - - H group after the first of these groups entered the reaction [2]. This study is concerned with the polyaddition of 1,3-bis-(dimcthylsilyl)tetramethylcyclodisilazane to 1,3-butadiene hexamethylcyclotetrasiloxane, diallylisophthalate and acetylene in the presence of chloroplatinic acid and rhodium compounds. 1,3-Bis-(dimethylsilyl)tetrametbylcyclodisilazane reacts with 1,3-butadienehexamethylcyclotetrasiloxane within a few minutes on being added to an equimolecular mixture of 1.5 x 10 -5 mole/1. H~PtC16.6H20 in the form of 0.1M solution in tetrahydrofuran and heating the reaction mixture to 170 °. As a result of t h e reaction a polymer product with a specific viscosity of 0.28 is formed. The reaction * Vysokomol. soyed. A21: into. 4, 907-913, 1979. 996
Polyaddition reaction of t,3-bis- (dimethylsilyl) tetramethylcyclodisilazane
997
takes place by the system:
Me
Me \
Me /
Si
Me
Me
l
Me [
I / \ I CHz--CH--Si--O--Si--CH=CH2 nH--Si-- N N--Si--H -~ n I I I \ / I 0 0 Me Si Me I [ M g \Me M%Si--O--SiMe'z Me Me
Me Si
.Me Me
H2PtCI,.6H,O
Me
Si--O--Si--(CH2)2--
Si--N N--Si--(CHz)a 0 0 I I I \ / I Me2Si--O--SiMe~ Me Si Me
/\
I Me Me Me Me Me Me \/ I I /~i--O--~i--CI-I=CH2 Me Si Me I / \ I --Si--N N--Si--(CH2)2 0 0 f \ / I I Me Si Me Me~Si--O--SiM% /\ Me Me
n-I
The I R spectrum of the polymer (I) formed indicates t h a t cyclodisilazane and eyclotetrasiloxane fragments are retained in the polymer chain. I n the region of 1030 cm-1 there is an absorption band typical of the endocylic S i - - N bond of the Si4N ~ skeleton, while in the region of 1090-1080 cm-1 there is a band typical of an eight membered siloxane ring. Attempts to s t u d y reaction kinetics at 100 and 170 ° and a catalyst concentration of 1.5)< 10 -5 to 1.5× 10 -4 mole/1, were unsuccessful since the reaction did not take place in practice on adding the catalyst to the reaction mixture thermostatically controlled at these temperatures. At the same time, as described previously, on adding the catalyst to a cold reaction mixture, followed by heating, the reaction took place rapidly. Figure la shows the variation over a period of time of the conversion of S i - - H groups at 170 °, when the catalyst is added to the cold reaction mixture. I t can be seen t h a t an induction period is observed within 2 min, during which conversion does not exceed a few per cents and then reaction rate sudderdy increases and conversion reaches 96% in 3 rain. This specific course of the reaction indicates t h a t it only catalyses a platinum complex of intermediate valency, which is formed during the reduction of H2PtC16 in the process of heating the reaction mixture. I f reduction takes place at high temperature, no complex is formed, since platinum is reduced to zero valency where it does not catalyse this reaction. The assumption concerning the formation of an active complex is also confirmed by the fact t h a t the reaction is
998
ANDRIANOV et al.
K.A.
not interrupted if the reaction mixture is added in parts after the reaction has started and the temperature of the reaction mixture thermostatically controlled. I t was also established that 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane is less reactive than 1,3-dihydrotetramethyldisilazane and 1,3-dihydro-l,3-
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FxG. 1. V a r i a t i o n of t h e c o n v e r s i o n of Si--I-I groups in t h e process of t h e r e a c t i o n of 1,3-bis(dimethylsilyl)tetramethyleyclodisilazane with 1,3-butadienehexamethylcyclotetrasiloxane (a) a n d d i a l l y l i s o p h t h a l a t e (b-d) at t e m p e r a t u r e s of 170 (a, b), 150 (lc, 2c a n d d) a n d 110 ° (3c) o v e r a p e r i o d of t i m e . Catalysts: a--H2PtCle.6H=O, 1.5× 10 -s mole/1.; b, / d - - s a m e , 1 × 10 -4 mole/1.; v, 2 d - - r h o d i u m a c e t y l a c e t o n a t e d i e a r b o n y l 1 × 104 (lc, 3c, 2d) a n d 1 × 10 -5 mole/1. (2c).
dimethyl-l,3-diphenylsilazane. The last two compounds react with 1,3-butadienehexamethylcyclotetrasiloxane with a concentration of HzPtC16.6H~O of 1.5 × 10 -5 mole/1, and a temperature of 50 ° to form polymers of the following structure. Me Me I I R
I
I
I R'
I R'
H - - --$i--NH--Si--(CH~h
0
0
1
I
(CHub-- --
Me--Si--O--Si--Me
l
Me
l
Me
n-1
Polyaddition reaction of 1,3-bis-(dimethylsilyl) tetramethylcyelodisilazane Me
R ]
R 1
I
I
Me
I I /S[i--0--~iCH----CHz
-- Si--NH--Si--(CH2)20 R'
999
0
I
R'
]
MeSi--O--SiMe
I
I
Me
Me
where R = R ' ~ M e (polymer II) and R = M e ; R ' ~ P h (polymer III). 1,3-Bis-(dimethylsilyl)tetramethylcyclodisilazane does not enter this reaction at 50 °. Polyaddition of 1,3-bis-(dimethylsilyl)tetramcthylcyclodisilazane to acetylene was carried out at normal pressure in acetylene:
Me \/ Me
!
nH--Si--N
I Me Me
\/
•
H--
Si
Me
/\
I
N--Si--H-~ n
\s( '
---Me-
Me
\/ Si / Me
Me
\/
Me
Me
- - J i - - N / S \ N--Si--(CH2)~-[
I
CH--=CH--,
I Me
M/ \Me Me Si
Me
Me
Si] -- N /
r
I
Me
Me
\Me
Si
~-1
Me
\ N--Si--CH----Ct [
\/ Si /\ Me
I
Me Me
IV Interaction was carried out at 170 ° and a concentration of H2PtCI 6. 6H20 of 5 × l0 -4 mole/1. After 6 hr a viscous product was formed as a result of the reaction, which solidifies on cooling and has a glass temperature of 153 °. Analysis of I R spectra of this product indicates that there is an absorption band in the 1030 cm -1 region, which corresponds to a S i - - N endocyclic bond of the Si4N2 cyclodisilazane fra.me. The product of poly-addition is soluble in hot toluene, b u t precipitates on cooling the solution. After reprecipitation from toluene polymer yield is 90%. The reaction of hydride addition to diallylisophthalate was carried out in the presence of H2PtC16- 6I-I20 and rhodium acetylacetonate dicarbonyl in the form of 0-1 M solutions in T H F and Rh4(COh2 , dissolved in 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane. The interactio n of 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane with diallylisophthalate takes place in 20 rain to a conversion of 98% on adding to an equimolecular mixture 1 × 10 -4 mole/1. H2PtC1 e• 6 t - I ~ O , followed b y heating the reaction mixture to 170 °. Figure lb indicates t h a t if there a brief induction period at the beginning of the reaction, subsequently up to the end of the process there is a linear relation between conversion and time. As a result of the reaction a polymer product is formed with an intrinaie
K . A . A~DRIANOVet
I000
at.
viscosity of 0.41 dl/g Me Me [
Me
\/ Si / ~.
Me ]
0 [] ~
nltSi--N N--Sill + nCH~=CHCHzOC--, [ %/ [ Me Si Me Mo/
0 [I
'
/--COCH~CH=CH~
H2PtCIv6H20
)
\Me
Me
Me
I / \ J H ~ II --~ H-- --Si--N N--Si--(CH~)3--O--C--~_~--C--0--(CI~) 3_ I \ / I ' Me Si Me /\ Me Me n-z Me
Me
\/
Me
Si
Me
0
0
--[i--N/S \ N--Si--(CH~)3--O--C-I IJ ~x~_.~--C--O--CH2--CH /~ II =GH 2 L \ / I M9 Si Me V In the presence of rhodium acetylacetonate dicarbonyl and rhodium carbony this reaction has an induction period, after which rate suddenly increases and conversion for S i - - H groups reaches 1 0 0 ~ in 15-20 see: Variation of process conditions and the amount of catalyst does not have a marked effect on rate, merely the duration of the induction period changes. I f at 150 ° and a concentration of rhodium acetylaeetonatediearbonyl of 1 × 10 -~ mole/1. (Fig. le; curve 1) the induction period lasts 1.5 rain, at the same temperature and a catalyst concentration of I × 10 .5 mole/1. (Fig. lc; curve 2) the induction period lasts 3 rain. On reducing catalyst concentration b y a further order of magnitude, the reaction does not take place. At a temperature of I10 ° and a catalyst concentration of 1 × 10 -4 mol~/1., the induction period increases to 5 rain, after which the reaction takes place rapidly (Fig. lc; curve 3). I t should be npted that in the presence of ehloroplatinie acid under the same conditions (150 °, catalyst concentration 1 × I0 -4 mole/1.) the reaction takes place at a much lower rate (Fig. ld; curve 1) than in the presence of a rhodium catalyst (Fig. ld; curve 2). It should also be n o t e d that on using H~PtC1 e. 6H20, products of higher molecular weights are formed than in the case of rhodium catalysts. When the reaction is carried out in the presence of the latter, [0] values do not exceed 0.2 dl/g. This indicates that on using rhodium compounds as catalysts, secondary reactions such as, for example, reaction at the ester bond of diallylisophthalate resulting in the
Polyaddition reaction of 1,3-bis-(dimethylsilyl) tetramethylcyclodisilazane
1001
rupture of the C - - O - - C bond and the rupture of the growing chain, take place to an increased extent. An analysis of the course of reactions in the presence of rhodium catalysts indicates t h a t the formation of an intermediate complex is, apparently, one of the most important stages. When a complex is formed'reactions take place at a high rate. I t m a y be assumed from results t h a t 1,3-bis-(dimethylsilyl)tetramethylcyelodisilazane is highly reactive, but one of the conditions of poly-addition is the formation of an intermediate complex, which requires t h e maintenance of certain conditions. a b
I ~#O
-,,f,
/1/ IV
II
80 I
~00
i
800 ~ °0
I
/400
800 7:,°0
FIG. 2. TOA (a) ~ d DTA (b) ouFves. 1~Tumborsof curves correspond to numbers of polymers in the text.
Thermal-oxidizing degradation of products synthesized was studied using a /)O-102 derivatograph in air in the temperature range of 20-800 ° at a rate of heating of 5 deg/min. Figure 2a shows t h a t the addition of the silazane fragment to the main chain of the polymer molecule increases the resistance of the polymer to thermal-oxidizing degradation. For a carboxyloxane polymer [5] of the following structure: Me Me Me Me H-- --Si--O--Si(CH2)2Si--O--Si{CH2)2-] l 1 I Me Me 0 0 I
Me I
I
Me--Si--O--Si--Me / \ Me Me VI Me Me Me •
]
I
1
--Si--O--Si(CH~)..Si--O--SiCH== Ctt2, I
Me
1
Me
{
I
0
0
I
I
Me--Si--O--Si--Me / \ Me Me
n--I
1002
K.A.
A~D~IANOV ct al.
used for comparison 10~/o weight loss is observed at 310 °. The addition to the chain of tetraorganodisilazane fragments (polymers II and III) increases this temperature to 380-410 °. Even higher heat stability is observed on adding a tertiary nitrogen atom to the polymer. For a polymer synthesized using 1,3-bis(dimethylsflyl)tetramethylcyclodisilazane and 1,3-butadienehexamethylcyelotetrasiloxane (polymer I) 10% weight loss is observed at 480 °. Results of DTA (Fig. 2b) also indicate that the addition to the polymer chain of silazane and particularly cyclodisilazane fragments increases the stability of polymers to thermal-oxidizing degradation. For polymer analogue VI the maximum rate of decomposition is at 500 °, whereas polymer I with cyclodisilazane fragments has a maximum in the region of 570 °. A comparison of results of TGA using polymers I, IV and V, containing cyclodisilazane fragments in the main chains of the molecule shows that resistance to degradation is lower for earbo-organosilazane polymers IV and V than for polymer I, in which cyclodisilazane and cyclosiloxane fragments alternate. At a temperature of 350 ° carbosilazane polymers sustain an approximate weight loss of 10%, while for earbosilazanesiloxane polymers this value is reached at 480 ° . Similar heat stability may only be attributed to the addition of organocyclosiloxane units to the chain. It may be concluded from these results that the addition of silazane units to the main polymer chain, particularly those with a tertiary nitrogen atom, increases the heat stability of these polymers, the polymer in which cyclodisilazano and cyclosiloxane fragments alternate being of the highest heat stability. Reaction of 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane with 1,3-butadienehexamethylcyelotetrasiloxane. 5-4 g (0.02 mole) 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane, 6.4 g (0.02 mole) 1,3-butadienehexamethylcyelotetrasiloxane and 18 ~1 0.1 ~ solution of H~PtCle-6H~O in T H F were placed in a reaction flask. While agitating the reaction m i x t u r e was heated to 170 ° for 3-5 hr. The intrinsic viscosity of the polymer a f t e r heating in v a c u u m to 17()°/2 torr was 0.28 dl/g (toluene, 25°). Found, %: C 37.12; I-I 8.70; /~" 4.83; Si 38.50. Calculated for C18Hs01q~O~Sis, %: C 37.06; i 8-64; N 4.81; Si 38.50.
Reaction of 1,3-dihydrotetramethyldisilazane
with 1,3.butadienehexamethylcyelotctrasil.
oxane. 3.99 g (0.03 mole) 1,3-dihydrotetramethyldisilazane, 9-6 g (0.03 mole) 1,3-butadienehexamethylcyclotetrasiloxane and 20~1 0.1 M solution of H2PtCle'6H~O in T H F were placed in a reaction flask. The reaction m i x t u r e was heated to 50 ° for 24 hr. After reprecipitation from hexane and evacuation at 50°/1. torr 12.01 g polymer (86~o of stoichiometric) was obtained; [t/] in toluene 0.16 dl./g.
Reaction of 1,3-dihydro-l,3-dimethyl-l,3.diphenyldisilazane with 1,3.butadienehexamethylcyclotetrasiloxane. 5.15 g (0.02 mole) 1,3-dihydro-l,3-dimethyl-l,3-diphenyldisilazane, 6.45 g (0.02 mole) 1,3-butadienehexamethylcyclotetrasiloxane and 18 ]A 0.1 ~ solution o f H2PtCI6.6H~O in T H F was heated to 50 ° for 24 hr. After reprecipitation from hexane a n d evacuation at 50°/2 torr 9 g (77~o of stoichiometric) polymer with [~] 0.30 dl/g (toluene) was obtained. Reaction of ~l,3-bis.(dime~hylsilyl)tetramethylcyclodisilazane with acetylene. Acetylene was blown through a mixture of 5.4 g (0.02 mole) 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane and 15/A 0.1 ~ solution of HzPtCI~'6H~O in T H F , it was then joined to a cell filled with acetylene and heated to 170 °. A viscous polymer product was formed after 6 hr, ~vhich became glass-like at room temperature. The polymer was dissolved in hot toluene
Copolymerization of v i n y l t r i m c t h y i (phenyl)silancs with butadiene
1003:
and filtered. On cooling the polymer precipitated, it was dried to constant weight at 200°/1 torr. 4.95 g (90% of stoichiometric) product with a glass temperature of 153 ° was obtained. Found, %: C 41.58; t t 9.58; 1~ 9.73; Si 38-67. Calculated for CloI-I2sI~I2Si4, ~o: C 41.61; I-I 9-77; 1~ 9.70; Si 38.92.
Reaction
of
1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane
with
diallylisophthalate.
13.1g (0.05 mole) 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane, 11.7 g (0.05 mole) diallylisophthalate and 30 ]~1 0.1 ~i solution of ]-t~PtCI~'6H20 in T H F was heated to 170°; the reaction came to an end after 25 rain. The intrinsic viscosity of the polymer in toluene was 0.41 dl./g. Found, %: Si 5.11. Calculated for C22I-I40N204Si4, %: 1N-i 5"50.
Translated by E. SEMERE REFERENCES l. K. A. A N D R I A N O V , L. M. K H A N A N A S H V I L I , V. M. KOPYLOV and T. V. N E S T E R O V A , Izv. AN SSSI~, ser. khim., 351, 1968 2. K. A. ANDRIANOV, L. M. KHANANASHVILI, V. M. KOPYLOV and A. A. V Y A Z ' M I T L NOVA, Izv. A N SSSR, ser. khim., 1539, 1969 3. Ye. P. LEBEDEV and V. O. R E I K H S F E L ' D , Zh. obshch, khimii 38: 655, 1968 4. K. A. ANDRIANOV, V. M. KOPYLOV, M. J. SHKOL'NIK and Ye. A. K O R O L E V A , Auth. Cert. 472952, 1974; Byull. izobr. !~o., 21, 1975 5. A. A. ZHDANOV, K. A. ANDRIANOV and A. P. MALYKHIN, Dold. AN SSSR 211: 1104, 1973
Polymer Science U.S.S.I~. Vol. 21, pp. 1003-1010. ~) Pergamon Press Ltd. 1080. Printed in Poland
0032-3950/79/0401-1003507.50/O~
REGULARITIES OF COPOLYMERIZATION OF VINYLTRIMETHYL(PHENYL)SILANES WITH BUTADIENE INITIATED WITH n-BUTYLLITHIUM* V. M. I~IRYATINSKII,
N. S. NAMETKIN
and S. G. DURGA~'YA~
A. V. Topchiyev I n s t i t u t e of Petrochemical S~mthesis, U.S.S.R. A cad em y of Sciences
(Received 6 April 1978) A s t u d y was made of kinetics of anionic copolymerization of vinyltrimethylsilane and vinyldimethylphenylsilane with butadiene, the process being initiated with n - b u t y l l i t h i u m in a hydrocarbon medium; it was shown t h a t the rate of copolymerization increases on transition frem vinyltrimethylsilane to vinyldimethylphenylsilane. The rate of copolymeIizaticn of the vinyltrimethylsilane-butadiene pair increases with an increase in butadiene content and of the vinyldimethylphenylsilane-butadiene pair, with an increase in the content of vinyldimethylphenylsilane. * Vysokomol. soyed. A21: 1~o. 4, 914-919, 1979.
0032-3950/79/0401-0996507.50/0
STUDY OF THE POLYADDITION REACTION OF 1,3-BIS-(DIMETHYLSILYL) TETRAMETHYLCYCLODISILAZANE TO UNSATURATED COMPOUNDS* K. A. ANImlAN0V (dee.), M. I. SHKOL'NIK, V. M. K01"rL0V, L. M. KHANAlVASHVILI and P. L. PRIKHOD'K0 M. V. Lomonosov I n s ti tu te of Fine Chemical Technology, Moscow
(Received 6 April 1978) A study was made of p'olyaddition of 1,3-bis-(dimethylsilyl)tctramethylcyclodisilazane to unsaturated organic and organosilicon compounds. I t was shown t h a t 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane is highly reactive, but one of t h e reaction conditions is the formation of an intermediate catalyst complex. A study was made of thermal oxidizing breakdo~ua of polymers synthesized and it was shown t h a t the addition to the polymer chain of a cyclodisilazane fragment increases resistance to thermal oxidizing breakdown.
TH~l~E are several studies in the literature, which describe the addition of hydride organosilazanes containing a hydrogen atom and organic radicals at the nitrogen atom to unsaturated compounds [1-4]. I t was found that in contrast to organosiloxanes, organosilazanes are characterized by several properties due to structure. The addition of hydride organosilazanes containing hydrogen at the nitrogen atom to unsaturated compounds is accompanied by a seconadary reaction o f dehydrocondensation [l, 3] and on replacing hydrogen at the nitrogen atom in 1,3-dihydrotetramethyldisilazane by an organic radical a strong reduction is observed in the reactivity of the second S i - - H group after the first of these groups entered the reaction [2]. This study is concerned with the polyaddition of 1,3-bis-(dimcthylsilyl)tetramethylcyclodisilazane to 1,3-butadiene hexamethylcyclotetrasiloxane, diallylisophthalate and acetylene in the presence of chloroplatinic acid and rhodium compounds. 1,3-Bis-(dimethylsilyl)tetrametbylcyclodisilazane reacts with 1,3-butadienehexamethylcyclotetrasiloxane within a few minutes on being added to an equimolecular mixture of 1.5 x 10 -5 mole/1. H~PtC16.6H20 in the form of 0.1M solution in tetrahydrofuran and heating the reaction mixture to 170 °. As a result of t h e reaction a polymer product with a specific viscosity of 0.28 is formed. The reaction * Vysokomol. soyed. A21: into. 4, 907-913, 1979. 996
Polyaddition reaction of t,3-bis- (dimethylsilyl) tetramethylcyclodisilazane
997
takes place by the system:
Me
Me \
Me /
Si
Me
Me
l
Me [
I / \ I CHz--CH--Si--O--Si--CH=CH2 nH--Si-- N N--Si--H -~ n I I I \ / I 0 0 Me Si Me I [ M g \Me M%Si--O--SiMe'z Me Me
Me Si
.Me Me
H2PtCI,.6H,O
Me
Si--O--Si--(CH2)2--
Si--N N--Si--(CHz)a 0 0 I I I \ / I Me2Si--O--SiMe~ Me Si Me
/\
I Me Me Me Me Me Me \/ I I /~i--O--~i--CI-I=CH2 Me Si Me I / \ I --Si--N N--Si--(CH2)2 0 0 f \ / I I Me Si Me Me~Si--O--SiM% /\ Me Me
n-I
The I R spectrum of the polymer (I) formed indicates t h a t cyclodisilazane and eyclotetrasiloxane fragments are retained in the polymer chain. I n the region of 1030 cm-1 there is an absorption band typical of the endocylic S i - - N bond of the Si4N ~ skeleton, while in the region of 1090-1080 cm-1 there is a band typical of an eight membered siloxane ring. Attempts to s t u d y reaction kinetics at 100 and 170 ° and a catalyst concentration of 1.5)< 10 -5 to 1.5× 10 -4 mole/1, were unsuccessful since the reaction did not take place in practice on adding the catalyst to the reaction mixture thermostatically controlled at these temperatures. At the same time, as described previously, on adding the catalyst to a cold reaction mixture, followed by heating, the reaction took place rapidly. Figure la shows the variation over a period of time of the conversion of S i - - H groups at 170 °, when the catalyst is added to the cold reaction mixture. I t can be seen t h a t an induction period is observed within 2 min, during which conversion does not exceed a few per cents and then reaction rate sudderdy increases and conversion reaches 96% in 3 rain. This specific course of the reaction indicates t h a t it only catalyses a platinum complex of intermediate valency, which is formed during the reduction of H2PtC16 in the process of heating the reaction mixture. I f reduction takes place at high temperature, no complex is formed, since platinum is reduced to zero valency where it does not catalyse this reaction. The assumption concerning the formation of an active complex is also confirmed by the fact t h a t the reaction is
998
ANDRIANOV et al.
K.A.
not interrupted if the reaction mixture is added in parts after the reaction has started and the temperature of the reaction mixture thermostatically controlled. I t was also established that 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane is less reactive than 1,3-dihydrotetramethyldisilazane and 1,3-dihydro-l,3-
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I
120
FxG. 1. V a r i a t i o n of t h e c o n v e r s i o n of Si--I-I groups in t h e process of t h e r e a c t i o n of 1,3-bis(dimethylsilyl)tetramethyleyclodisilazane with 1,3-butadienehexamethylcyclotetrasiloxane (a) a n d d i a l l y l i s o p h t h a l a t e (b-d) at t e m p e r a t u r e s of 170 (a, b), 150 (lc, 2c a n d d) a n d 110 ° (3c) o v e r a p e r i o d of t i m e . Catalysts: a--H2PtCle.6H=O, 1.5× 10 -s mole/1.; b, / d - - s a m e , 1 × 10 -4 mole/1.; v, 2 d - - r h o d i u m a c e t y l a c e t o n a t e d i e a r b o n y l 1 × 104 (lc, 3c, 2d) a n d 1 × 10 -5 mole/1. (2c).
dimethyl-l,3-diphenylsilazane. The last two compounds react with 1,3-butadienehexamethylcyclotetrasiloxane with a concentration of HzPtC16.6H~O of 1.5 × 10 -5 mole/1, and a temperature of 50 ° to form polymers of the following structure. Me Me I I R
I
I
I R'
I R'
H - - --$i--NH--Si--(CH~h
0
0
1
I
(CHub-- --
Me--Si--O--Si--Me
l
Me
l
Me
n-1
Polyaddition reaction of 1,3-bis-(dimethylsilyl) tetramethylcyelodisilazane Me
R ]
R 1
I
I
Me
I I /S[i--0--~iCH----CHz
-- Si--NH--Si--(CH2)20 R'
999
0
I
R'
]
MeSi--O--SiMe
I
I
Me
Me
where R = R ' ~ M e (polymer II) and R = M e ; R ' ~ P h (polymer III). 1,3-Bis-(dimethylsilyl)tetramethylcyclodisilazane does not enter this reaction at 50 °. Polyaddition of 1,3-bis-(dimethylsilyl)tetramcthylcyclodisilazane to acetylene was carried out at normal pressure in acetylene:
Me \/ Me
!
nH--Si--N
I Me Me
\/
•
H--
Si
Me
/\
I
N--Si--H-~ n
\s( '
---Me-
Me
\/ Si / Me
Me
\/
Me
Me
- - J i - - N / S \ N--Si--(CH2)~-[
I
CH--=CH--,
I Me
M/ \Me Me Si
Me
Me
Si] -- N /
r
I
Me
Me
\Me
Si
~-1
Me
\ N--Si--CH----Ct [
\/ Si /\ Me
I
Me Me
IV Interaction was carried out at 170 ° and a concentration of H2PtCI 6. 6H20 of 5 × l0 -4 mole/1. After 6 hr a viscous product was formed as a result of the reaction, which solidifies on cooling and has a glass temperature of 153 °. Analysis of I R spectra of this product indicates that there is an absorption band in the 1030 cm -1 region, which corresponds to a S i - - N endocyclic bond of the Si4N2 cyclodisilazane fra.me. The product of poly-addition is soluble in hot toluene, b u t precipitates on cooling the solution. After reprecipitation from toluene polymer yield is 90%. The reaction of hydride addition to diallylisophthalate was carried out in the presence of H2PtC16- 6I-I20 and rhodium acetylacetonate dicarbonyl in the form of 0-1 M solutions in T H F and Rh4(COh2 , dissolved in 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane. The interactio n of 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane with diallylisophthalate takes place in 20 rain to a conversion of 98% on adding to an equimolecular mixture 1 × 10 -4 mole/1. H2PtC1 e• 6 t - I ~ O , followed b y heating the reaction mixture to 170 °. Figure lb indicates t h a t if there a brief induction period at the beginning of the reaction, subsequently up to the end of the process there is a linear relation between conversion and time. As a result of the reaction a polymer product is formed with an intrinaie
K . A . A~DRIANOVet
I000
at.
viscosity of 0.41 dl/g Me Me [
Me
\/ Si / ~.
Me ]
0 [] ~
nltSi--N N--Sill + nCH~=CHCHzOC--, [ %/ [ Me Si Me Mo/
0 [I
'
/--COCH~CH=CH~
H2PtCIv6H20
)
\Me
Me
Me
I / \ J H ~ II --~ H-- --Si--N N--Si--(CH~)3--O--C--~_~--C--0--(CI~) 3_ I \ / I ' Me Si Me /\ Me Me n-z Me
Me
\/
Me
Si
Me
0
0
--[i--N/S \ N--Si--(CH~)3--O--C-I IJ ~x~_.~--C--O--CH2--CH /~ II =GH 2 L \ / I M9 Si Me V In the presence of rhodium acetylacetonate dicarbonyl and rhodium carbony this reaction has an induction period, after which rate suddenly increases and conversion for S i - - H groups reaches 1 0 0 ~ in 15-20 see: Variation of process conditions and the amount of catalyst does not have a marked effect on rate, merely the duration of the induction period changes. I f at 150 ° and a concentration of rhodium acetylaeetonatediearbonyl of 1 × 10 -~ mole/1. (Fig. le; curve 1) the induction period lasts 1.5 rain, at the same temperature and a catalyst concentration of I × 10 .5 mole/1. (Fig. lc; curve 2) the induction period lasts 3 rain. On reducing catalyst concentration b y a further order of magnitude, the reaction does not take place. At a temperature of I10 ° and a catalyst concentration of 1 × 10 -4 mol~/1., the induction period increases to 5 rain, after which the reaction takes place rapidly (Fig. lc; curve 3). I t should be npted that in the presence of ehloroplatinie acid under the same conditions (150 °, catalyst concentration 1 × I0 -4 mole/1.) the reaction takes place at a much lower rate (Fig. ld; curve 1) than in the presence of a rhodium catalyst (Fig. ld; curve 2). It should also be n o t e d that on using H~PtC1 e. 6H20, products of higher molecular weights are formed than in the case of rhodium catalysts. When the reaction is carried out in the presence of the latter, [0] values do not exceed 0.2 dl/g. This indicates that on using rhodium compounds as catalysts, secondary reactions such as, for example, reaction at the ester bond of diallylisophthalate resulting in the
Polyaddition reaction of 1,3-bis-(dimethylsilyl) tetramethylcyclodisilazane
1001
rupture of the C - - O - - C bond and the rupture of the growing chain, take place to an increased extent. An analysis of the course of reactions in the presence of rhodium catalysts indicates t h a t the formation of an intermediate complex is, apparently, one of the most important stages. When a complex is formed'reactions take place at a high rate. I t m a y be assumed from results t h a t 1,3-bis-(dimethylsilyl)tetramethylcyelodisilazane is highly reactive, but one of the conditions of poly-addition is the formation of an intermediate complex, which requires t h e maintenance of certain conditions. a b
I ~#O
-,,f,
/1/ IV
II
80 I
~00
i
800 ~ °0
I
/400
800 7:,°0
FIG. 2. TOA (a) ~ d DTA (b) ouFves. 1~Tumborsof curves correspond to numbers of polymers in the text.
Thermal-oxidizing degradation of products synthesized was studied using a /)O-102 derivatograph in air in the temperature range of 20-800 ° at a rate of heating of 5 deg/min. Figure 2a shows t h a t the addition of the silazane fragment to the main chain of the polymer molecule increases the resistance of the polymer to thermal-oxidizing degradation. For a carboxyloxane polymer [5] of the following structure: Me Me Me Me H-- --Si--O--Si(CH2)2Si--O--Si{CH2)2-] l 1 I Me Me 0 0 I
Me I
I
Me--Si--O--Si--Me / \ Me Me VI Me Me Me •
]
I
1
--Si--O--Si(CH~)..Si--O--SiCH== Ctt2, I
Me
1
Me
{
I
0
0
I
I
Me--Si--O--Si--Me / \ Me Me
n--I
1002
K.A.
A~D~IANOV ct al.
used for comparison 10~/o weight loss is observed at 310 °. The addition to the chain of tetraorganodisilazane fragments (polymers II and III) increases this temperature to 380-410 °. Even higher heat stability is observed on adding a tertiary nitrogen atom to the polymer. For a polymer synthesized using 1,3-bis(dimethylsflyl)tetramethylcyclodisilazane and 1,3-butadienehexamethylcyelotetrasiloxane (polymer I) 10% weight loss is observed at 480 °. Results of DTA (Fig. 2b) also indicate that the addition to the polymer chain of silazane and particularly cyclodisilazane fragments increases the stability of polymers to thermal-oxidizing degradation. For polymer analogue VI the maximum rate of decomposition is at 500 °, whereas polymer I with cyclodisilazane fragments has a maximum in the region of 570 °. A comparison of results of TGA using polymers I, IV and V, containing cyclodisilazane fragments in the main chains of the molecule shows that resistance to degradation is lower for earbo-organosilazane polymers IV and V than for polymer I, in which cyclodisilazane and cyclosiloxane fragments alternate. At a temperature of 350 ° carbosilazane polymers sustain an approximate weight loss of 10%, while for earbosilazanesiloxane polymers this value is reached at 480 ° . Similar heat stability may only be attributed to the addition of organocyclosiloxane units to the chain. It may be concluded from these results that the addition of silazane units to the main polymer chain, particularly those with a tertiary nitrogen atom, increases the heat stability of these polymers, the polymer in which cyclodisilazano and cyclosiloxane fragments alternate being of the highest heat stability. Reaction of 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane with 1,3-butadienehexamethylcyelotetrasiloxane. 5-4 g (0.02 mole) 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane, 6.4 g (0.02 mole) 1,3-butadienehexamethylcyelotetrasiloxane and 18 ~1 0.1 ~ solution of H~PtCle-6H~O in T H F were placed in a reaction flask. While agitating the reaction m i x t u r e was heated to 170 ° for 3-5 hr. The intrinsic viscosity of the polymer a f t e r heating in v a c u u m to 17()°/2 torr was 0.28 dl/g (toluene, 25°). Found, %: C 37.12; I-I 8.70; /~" 4.83; Si 38.50. Calculated for C18Hs01q~O~Sis, %: C 37.06; i 8-64; N 4.81; Si 38.50.
Reaction of 1,3-dihydrotetramethyldisilazane
with 1,3.butadienehexamethylcyelotctrasil.
oxane. 3.99 g (0.03 mole) 1,3-dihydrotetramethyldisilazane, 9-6 g (0.03 mole) 1,3-butadienehexamethylcyclotetrasiloxane and 20~1 0.1 M solution of H2PtCle'6H~O in T H F were placed in a reaction flask. The reaction m i x t u r e was heated to 50 ° for 24 hr. After reprecipitation from hexane and evacuation at 50°/1. torr 12.01 g polymer (86~o of stoichiometric) was obtained; [t/] in toluene 0.16 dl./g.
Reaction of 1,3-dihydro-l,3-dimethyl-l,3.diphenyldisilazane with 1,3.butadienehexamethylcyclotetrasiloxane. 5.15 g (0.02 mole) 1,3-dihydro-l,3-dimethyl-l,3-diphenyldisilazane, 6.45 g (0.02 mole) 1,3-butadienehexamethylcyclotetrasiloxane and 18 ]A 0.1 ~ solution o f H2PtCI6.6H~O in T H F was heated to 50 ° for 24 hr. After reprecipitation from hexane a n d evacuation at 50°/2 torr 9 g (77~o of stoichiometric) polymer with [~] 0.30 dl/g (toluene) was obtained. Reaction of ~l,3-bis.(dime~hylsilyl)tetramethylcyclodisilazane with acetylene. Acetylene was blown through a mixture of 5.4 g (0.02 mole) 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane and 15/A 0.1 ~ solution of HzPtCI~'6H~O in T H F , it was then joined to a cell filled with acetylene and heated to 170 °. A viscous polymer product was formed after 6 hr, ~vhich became glass-like at room temperature. The polymer was dissolved in hot toluene
Copolymerization of v i n y l t r i m c t h y i (phenyl)silancs with butadiene
1003:
and filtered. On cooling the polymer precipitated, it was dried to constant weight at 200°/1 torr. 4.95 g (90% of stoichiometric) product with a glass temperature of 153 ° was obtained. Found, %: C 41.58; t t 9.58; 1~ 9.73; Si 38-67. Calculated for CloI-I2sI~I2Si4, ~o: C 41.61; I-I 9-77; 1~ 9.70; Si 38.92.
Reaction
of
1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane
with
diallylisophthalate.
13.1g (0.05 mole) 1,3-bis-(dimethylsilyl)tetramethylcyclodisilazane, 11.7 g (0.05 mole) diallylisophthalate and 30 ]~1 0.1 ~i solution of ]-t~PtCI~'6H20 in T H F was heated to 170°; the reaction came to an end after 25 rain. The intrinsic viscosity of the polymer in toluene was 0.41 dl./g. Found, %: Si 5.11. Calculated for C22I-I40N204Si4, %: 1N-i 5"50.
Translated by E. SEMERE REFERENCES l. K. A. A N D R I A N O V , L. M. K H A N A N A S H V I L I , V. M. KOPYLOV and T. V. N E S T E R O V A , Izv. AN SSSI~, ser. khim., 351, 1968 2. K. A. ANDRIANOV, L. M. KHANANASHVILI, V. M. KOPYLOV and A. A. V Y A Z ' M I T L NOVA, Izv. A N SSSR, ser. khim., 1539, 1969 3. Ye. P. LEBEDEV and V. O. R E I K H S F E L ' D , Zh. obshch, khimii 38: 655, 1968 4. K. A. ANDRIANOV, V. M. KOPYLOV, M. J. SHKOL'NIK and Ye. A. K O R O L E V A , Auth. Cert. 472952, 1974; Byull. izobr. !~o., 21, 1975 5. A. A. ZHDANOV, K. A. ANDRIANOV and A. P. MALYKHIN, Dold. AN SSSR 211: 1104, 1973
Polymer Science U.S.S.I~. Vol. 21, pp. 1003-1010. ~) Pergamon Press Ltd. 1080. Printed in Poland
0032-3950/79/0401-1003507.50/O~
REGULARITIES OF COPOLYMERIZATION OF VINYLTRIMETHYL(PHENYL)SILANES WITH BUTADIENE INITIATED WITH n-BUTYLLITHIUM* V. M. I~IRYATINSKII,
N. S. NAMETKIN
and S. G. DURGA~'YA~
A. V. Topchiyev I n s t i t u t e of Petrochemical S~mthesis, U.S.S.R. A cad em y of Sciences
(Received 6 April 1978) A s t u d y was made of kinetics of anionic copolymerization of vinyltrimethylsilane and vinyldimethylphenylsilane with butadiene, the process being initiated with n - b u t y l l i t h i u m in a hydrocarbon medium; it was shown t h a t the rate of copolymerization increases on transition frem vinyltrimethylsilane to vinyldimethylphenylsilane. The rate of copolymeIizaticn of the vinyltrimethylsilane-butadiene pair increases with an increase in butadiene content and of the vinyldimethylphenylsilane-butadiene pair, with an increase in the content of vinyldimethylphenylsilane. * Vysokomol. soyed. A21: 1~o. 4, 914-919, 1979.