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Polymerization transformation of substituted vinyl germanium compounds
POLYMERIZATION TRANSFORMATION OF SUBSTITUTED VINYL GERMANIUM COMPOUNDS* ~[. S. NAMETKIN, S. G. DURGAR'YAN, L. I. TIKHONOVA a n d V. G. FILIPPOVA A. V. Topehiov Institute of Petrochemical Synthesis. U.S.S.l~. Acadcmy of Sciences (Received 12 November 1969) A STUDY is made in this p a p e r of p o l y m e r i z a t i o n t r a n s f o r m u t i o n s of alkeny! g e r m a n i u m c o m p o u n d s , n ~ m e l y n - p r o p e n y l t r i m e t h y l g e r m a n e , isopropenyl trim e t h y l g e r m a n e , ~ - s t y r y l t r i m e t h y l g e r m a n e , f l - s t y r y l t r i m e t h y l g e r m a n e , i.e. derivatives of v i n y l t r i m e t h y l g e r m a n e with s u b s t i t n e n t s in the ~ a n d fl-position in relation to the multiple bond. As has been established Ill, all these c o m p o u n d s have different reactivities in nueleophilic a d d i t i o n to org~no-lithium c o m p o u n d s . Thus, p r o p e n y l g e r m a n i u m c o m p o u n d s ~re tr~nsfbrmed in 5 hr to the e x t e n t of 1 5 - 2 0 % , where~s s t y r y l g e r m a n i u m c o m p o u n d s react q u a n t i t a t i v e l y during the same period with b u t y l lithium. Thus, the a d d i t i o n of a n electron a c c e p t e r s u b s t i t u e n t (phenyl group) to a vinyl germa~fiunl molecule considerably increases the a c t i v i t y of the multiple bond. EXPERIMENTAL
Methods of preparing substituted vinyl germanium compounds, purification of monomers and solvent and the synthesis of n-butyl-lithium were similar to those described previously [2-5]. Table 1 shows some of the properties of the compounds studied. Substituted vinyl germanium compounds were polymerized in evacuated (10 -3 ram) sealed ampoules with two branch pipes; a burette containing the initiator was connected to 9no while the other was connected to a vacuum system. After "couditioniag" the ampoule the monomer and solvent, which had been previously degassed, were re-condensed into it from graduated measurhlg tanks and the initiator added, followed by sealing the ainpouh~. The n-butyl-lithium concentration was 0.02 mole/l, in all experiments, monomer concentration 1.7-2-1 mole/1, and temperature 20°. Isoprene, butadiene, methyl methacrylate, aerylonitrilc and styrene were polymerized with carbanions obtained by reaction of n-butyl-lithium with vinyl-substituted germanium compounds in a device shown in the Figure. The device was connected to a vaeuunl system through section 1 mid a graduated burette containing the working initiator solution was connected to section 2. Ampoule 3 was carehflly ev~euated and "conditioned" and the requisite ~mount of chromatographically pure vinyl-substituted germanium compounds and a solvent previously dcgassed and treated with C2H5Li powder were recondensed. A calculated amount of n-butyl-lithium was then added and the device unsealed at the contracted part 4. After 24 hr when using ~- and fl-styryltrimethylgermanium compounds * Vysokomol. soyed. A13: No. 1, 168-173, 1971. 191
192
N . S. N A M E T K I N et al. T A B L E 1. SOME t'ROPERTIES OF SUBSTITUTED VIiWYL GERMA1WIUSY[ COMPOUI~DS
Compound formula
llame
CH3--CH----CH
I
n-Proponyltrimethylgormane
Boiling point, oC
n~
d~°
101/752
1.4341
1.0045
97.5/747
1.4294
1.0006
57/2.5
1.5365
1.1379
s3/4
1.5425
1.1441
Ge(CH3)3 CH~:C--Ge(CHa)3 Isoproponyltrimethylgermane
CH~=C--Ge(eH~), a-Styryltrimethylgermane
C]6I-I. CH----CI-I--Ge(CIt~).
fl-Styryltrimethylgermane
I
C6H5
and three iso- and n-propenyltrimethylgermauium compounds (preliminary control experiments established that the chromatographically established a m o u n t of free butane after decomposition of the reaction mass with water did not exceed the a m o u n t of butane dissolved in the butyl-lithium before the reaction) the device was connected to the distributive flange of the vacuum apparatus through section 5. After conventional preparation the ampoule was filled with hydrocarbon monomers previously degassed and the solvent and unsealed from the apparatus at the contracted part 7. Then by breaking membrane 9 with hammer 8
4
8 Y
7
Device for polymerization on carbanions obtained by the interaction of substituted vinyl germanium compounds and n-butyl-lithium.
Polymerization transformation of substituted vinyl germ~mium compounds
193
the monomer solution was decanted into the carbanion solution and contra~ted part 10 was rosealed, when ampoule 3 was retained at room temperature for a certain period of time. The monomers were polymerized with carbanions obtained by the reaction of n-butyllithium with substituted vinyl germanium compounds at 20°. n-Butyl-lithium solution was added, in a quantity to ensure a content of 0.005-0.02 mole/l, in the reaction mass, to substituted vinyl germanium compounds dissolved in heptane, of which the concentration was 0.6 1-2 mole/1. In all experiments the amount of substituted vinyl germanium compounds was 30-200 times more than that of n-butyl-lithium. After the initiator had fully reacted, when parallel experiments showed the absene~ of free n-butyl-lithium (chromatographic analysis), the monomers tested (acryh)nitrile, methyl methacrylate, styrene, butadiene and isoprene) were added to the polymerizatiotl systemso that their concentration~vas 1.1 5.9mole/l. The polymers obtained were separated with methanol and mtalysed. RESULTS AND DISCUSSION
As shovnl by a t t e m p t s to polymerize substituted vinyl g~,rmanium compounds (Table 1) with n-butyl-lithium, none of the monomers examined could, under the conditions indicated, be converted into polymer. I t may, however, be concluded from these experiments t h a t initiation apparently takes place fairly readily, which is confirmed by the appearance of colour after adding an initiator to the system. I n the case of a fl-styryltrimethylgermarfium compound the colour is bright red, the a-styryltrimethylgermane gives an orangered tint, the n-propenyltrimethylgermane a yellow tint, isopropenyltrimethylgermane develops no colour. Colour m a y be due to the appearance of earbanions formed b y adding n-butyl-lithium to the monomer molecule. The viscosity of the system did not increase with time, which proves the absence of polymerization. After opening the ampoule, in which polymerization was carried out, the colour disappeared and noticeable quantities of solid or liquid products of polymerization could not be separated. i t appears to us t h a t the absence of polymerization could either be the consequence of sterie hindrance or of the formation of stable adducts incapable of causing polymerization of either their "own", or "foreign" monomers. It is well knowat t h a t the presence of bulky substituents at the double bond is of importance at the stage of chain growth when the ne xt monomer unit is added to the growing carbanion. The second assumption could easily be examined by studying polymerization transformations of several widely used hydrocarbon monomers on carbanions obtained by interaction of substituted vinyl germanium compounds with n-butyllithium (when free initiators are absent from the system). Acrylonitrile, methyl methaerylate, styrene, butadiene, isoprene, were examined i.e. monomers for which polymerization on lithium alkylates has been extensively studied. Results of experiments indicate t hat almost all these monomers, except styrene, readily po]ymerize on carbanions of substituted e-alkenylgermanium compounds. Coltditions of polymerization and characteristics of polymers obtained arc shown in Table 2.
14 15
10 11 12 13
9
Exp. No.
TABLE
Ge(CHs)a
C,HgCH2--C-Li +
HC--C-HLi +
I
I-I~C a
Isoprene Vinyltrimethylsilane
Butadiene Buta~liene Isoprene Isoprene (2-stage addition) Vinyltrimethylsilane Acrylonitrile Methyl methacrylate Styrene Butadiene (2-stage addition)
Acrylonitrile Methyl methacrylate Styrene Butadiene (2-stage addition)
Monomers to be polymerized
OBTAINED
80.0 41.0 39.0 62.0
24-0 24.0 0.5 2-0 48.0 4"56 2-40 4-32
0.74 0-008 0"53 0"013 0'74 0-019 1.03 i 0"016 0-72 0"009
0.7010-018 0.53 i 0-013
0-74 10"009
3.33 2.40
5.1
1"60
20.0 24.0
63.0 48.0
97-0
34.0 98.0 83.0
2"0 24-0 24.0
2"20 2"80 3"30
0.005 0.006 0"018
0"75 0"76 0"70
72.0
99.3
72"0
5-93
0"77 ! 0"005
1"63
37.0 56.0
0'5 2.0
0"74 1 "03 0"72
4'32 1"63 1"60
yield, ~/o
0"019 0.016 0'009
polyvinyl butyl- monomerizagerlithmer tion mane ium polymer-ized time, hr
conc., mole/1.
Reaction conditions
~-SUBSTITUTED
0.12 0.80
0.70
0.83 0.24 0.59 0.52
0.22 0-56 0.18
1.1
0.62 0-41
1.4
6.5
5-3 -1.44 1.40
1-6 4.1 1.6
7-2
1.5 1.3
polymer Ge, vis- wt. ~/o cosity
Characteristics of the polymer
BY THE REACTIOI~ OF g- AND
AND n-BUTYL-LITHIUM
]BY C A R B A N I O N S
M-ETHYLGERMANE
OF MONOMERS INITIATED
Adduct of n-CaHgLi and vinyl germane
2. POLYMERIZATIOI~
1 "08
0"24
1 "60 1.20
0"24
1-50
0"9 0-25
0.12
1-61 1.20
Theoretically calculated Ge, ~o
VINYLTRI-
¢¢
21 22 23 24 25 26 27
20
16 17 18 19
Exp. No.
+
Ge(CH3)3
I
C4H~CH.~--C Li +
I
CH3
Gc(CH3)3
I
CHa--CH--C--HLi
I
Call9
A d d u c t of n-C4HgLi and vinyl germane
Isoprene Vinyltrirncthylsilane Acrylonitrile Methyl methaerylate Styrene Butadiene Isoprene Vinyltrimcthylsilane
Acrylonitrile Methyl methacrylat e Styrene Butadiene
M o n o m e r s to b e polymerized
0.65 0.73 0'62 1-25 0.63 0.61 0.65 0-73 0.62 1.25 0.63 0.61
0.021 0.011 0.021 0.006 0.012 0-019 0.021 0.013 0.021 0.007 0.012 0.019
3.8 2.10 1.84 1.10 3.1 1.9 3-8 1.83 1.84 1.10 3.1 1.9 0"5 2'0 48"0 24'0 24'0 24'0 0'5 2-0 48-0 24-0 84"0 24"0
95'0 74"0 74"0
60"0 40"0 39"0 53"0
76"0
20"0 93'0
0.17 0.26
0.18
0.19 0-21 0.9 0.47
0.I7
0.4 0-6
1.14 1.10
1.71 1-38
1.25 1.08
1-33 1.52
!polyyield, j m e r Ge, ~/o , visco- wt. ] sity
Characteristics of the polymer
polyv i n y l i butyl-~ m o n o m e r m erizagetlithp o l y m e r tion mane iron ized time, hr
cone., mole/1.
Reaction conditions
TABLE 2 (cont.)
0'98 1 '50
1'0
1 "82
1'10 0"92
1"29 1"35
Theoretically calculated Ge, ~/o
c
c
5~
v
c
c
c
196
N.S. NAMETKINet
al.
Analysis shows that the germanium content (experiments 1, 2, 10, 11, 16, 17, 22 and 23) of acrylonitrile-methylmethacrylate polymers obtained using all four carbanions is less than 1.6 °/o (i.e. the macromolecule contains only 1 alkenyl germanium unit). Thus, carbanions of substituted trimethyl germanium compounds only cause the polymerization of acrylonitrile and methyl methacrylate, but do not themselves participate in chain extension. Apparently, carbanions which have a terminal acrylonitrile or methyl methacrylate unit do not incorporate substituted alkenyl germanium compounds either because of weak basicity or, possibly, isomerization of the active end of the polymer chain to form a stable ion, which is unable to continue chain extension [6, 7]. A different pattern was observed with polymerization of butadiene and isoprene oll carbanions obtained from a- and fl-styryltrimethylgermanium coinpounds. On adding dienes to these carbanions the colour gradually disappeared and the viscosity of the system increased at the same time. A control experiment showed that if polymerization of butadiene is discontinued after 2 hr (Table 2, experiment 5) with a diene transformation of 340, the polymer contains only 1.6% germanium, which proves that in the initial stage of the reaction only diene is polymerizcd and the amount of fl-styryltrimethylgermanein the polymer chain is insignificant. In experiments when polymerization was carried out until to complete transformation of diene the colour typical of carbanions reappeared H
I
Li +
I
(CH3)3Ge--CH--C-Li+ or (CH3)3Ge--C---CH~--C4H9
Apparently in this case not only the carbanion formed from fl-styryltrimethylgermanc and n-butyl-lithium adds onto the diene, but also the carbanion which has a diene unit at the end adds on the fl-styryltrimethylgermane, which is confirmed by the appearance of colour. The germanium content in the polymer was 4.1% (Table 2, experiment 6) which corresponds to 5 styryltrimethylgermane units for each 95 units of butadiene contained in the polymer 6hain (with an initial molar ratio of 90 mole % butadiene and 10 mole % fl-styryltrimethylgermane). After addition of more diene to this system, the colour again disappears ~nd the diene added polymerizes. The amount of germanium in the polymer obtained after the second addition of diene increases. A copolymer is obviously formed in this case, but owing to the different rates of adding the monomers--diene and styryltrimethylgermane--to the ends of growing chains the latter, having lower activity, will mainly form part of the polymer chain at the end of polymerization after the diene monomer has almost completely been used in the system, a polymer being formed with alternating
Polymerization transformation of substituted vinyl germanium compounds
197
different monomer units. The viscosity of the copolymers obtained was 1.1 dl/g for polybutadiene and 0.83 dl/g for polyisoprene. The structure of the polybutadiene formed differs little from the structure of this polymer obtained during polymerization initiated with n-butyl-lithium (Table 3). T A B L E 3. S T I t U C T U R E OF I~OLYBUTADIENE OBTAIXED ~*VITI~ VARI:OUS I N I T I A T O R S , A~-~CORDINO
To
II~
sr~c~oscoelc RESULTS Nmnber of units o/ ~o
Polymerization initiator
1,2 n-Butyl-lithium Carbanion offl-styryltrimethylgermane and n-C,I-~Li Carbanion of a-styryltrimethylgermane and n-C4H~Li
7"0 10.5 12.5
I
trans
cis-
45"5 41.5 39'5
47.5 48-0 48"0
When dienes were polymerized on carbanions obtained by the interaction of n-butyl-lithium with methyl-substituted vinyltrimethylgermanium compounds the germanium content of the polymers was less than 1-5% with an almost qfiantitative transformation of diene. Each polydiene macromolecule obviously contains only one organic germanium group (Table 2, experiments 19, 20, 25, 26). Propenyl germanium compounds are apparently of lower activity compared with styryl germanium compounds i.e. earbanions prepared from propenyl germanium only cause polymerization of dienes, but organic germanium monomers do not take part in chain extension. On adding to carbanions substituted vinyl germanium compounds of styrene the colour disappeared immediately, but polymerization does not take place since stable adducts are apparently formed in the system which are unable to cause polymerization either of styrene or of the diene added to the reaction mixture obtained. It should be pointed out that the colour @pical of styrene carbanions was not observed. From results of polymerization transformation of substituted vinyltrimethylgermanium compounds it may be concluded that neither methyl nor phenylsubstituted vinyl germanium compounds polymerize on lithium alkyls, but form carbanions capable of causing polymerization of other monomers. Carbanions obtained from phenyl- and methyl-substituted vinyl germanium compounds differ markedly in activity as regards diene polymerization. If ~- and ~-styryltrimethylgermane form copolymers with dienes, carbanions of methyl-substituted vinyl germane only initiate polymerization of dienes but the propenyl trimethyl germanium compounds themselves do not take part in polymer chain extension. Consequently, the absence of polymerization of substituted vinyl germanium compounds is due to strong steric hindrance caused by the substituents at the multiple bond and the germanium atom. However, the activity of the carbaaions formed also has a certain effect on the processes studied.
A . A . BERLI~¢ et al.
198
CONCLUSIONS
(1) A study was made of polymerization transformations of acrylonitrile, methyl methacrylate, isoprene, butadiene, styrene on carbanions obtained by interaction of n-butyl-lithium and substituted vinyl germanium compounds. (2) It is shown that n-propenyltrimethylgermane, isopropenyltrimethylgermane, ~-styryltrimethylgermane, fl-styryltrimethylgermane form active carbanions, although they themselves do not polymerize with n-butyl-lithium. Translated by E. SEMERE
REFERENCES 1. N. S. NAMETKIN, S. G. DURGAR'YAN, L. I. TIKHONOVA, N. V. USHAKOV and M. V. POZDNYAKOVA, Dokl. AN SSSR 181: 1138, 1968 2. N. S. NAMETKIN, S. G. DURGAR'YAN and L. I. TIKHONOVA, Dokl. AN SSSR 172: 867, 1967 3. V. G. FILIPPOVA, N. S. NAMETKIN and S. G. DURGAR'YAN, Izv. AN SSSR, Otd. khim. n., 1727, 1966 4. N. S. NAMETKIN, S. G. DURGAR'YAN and V. S. KHOTIMSKII, Vysokomol. soyed. Al1: 2067, 1969 (Translated in Polymer Sci. U.S.S.R. 11: 9, 2360, 1969) 5. T. V. TALALAYEVA and K. A. KOCHESHKOV, Zh. organ, khim. 29: 392, 1953 6. R. K. GRAHAM, I. R. PANCHAK and M. I. KAMPF, J. Polymer Sci. 44: 411, 1960 7. P. CLAES and G. SMETS, Makromolek. Chem. 44-46: 212, 1961
STUDY OF THE ABILITY OF OLIGOESTERACRYLATES CONTAINING PHOSPHORUS TO POLYMERIZE* A. A.
BERLIN,
L. P.
RASKINA,
L. A. ZHIL'TSOVA and B. S. EL'TSEFON
All-Union Scientific Research Institute of 5{edicinal Polymers
(Received 14 November 1969)
THE principal relations of three-dimensional polymerization of oligomers have mainly been investigated using oligoesteracrylates (OEA) [1]. Oligoaestererylates able to polymerize and containing sulphur and silicon have recently been studied kinetically [2, 3]. Among the most interesting oligomers capable of polymerizing are the unsaturated oligoalkylphosphinates, which on copolymerization with conventional oligoestcracrylates or other unsaturated compounds produce fire-resistant polymers. However, there is no information in the literature concerning the polymerization ability of oligomers containing phosphorus. * Vysokomol. soyed. A13: :No. 1, 174-182, 1971.
Methods of preparing substituted vinyl germanium compounds, purification of monomers and solvent and the synthesis of n-butyl-lithium were similar to those described previously [2-5]. Table 1 shows some of the properties of the compounds studied. Substituted vinyl germanium compounds were polymerized in evacuated (10 -3 ram) sealed ampoules with two branch pipes; a burette containing the initiator was connected to 9no while the other was connected to a vacuum system. After "couditioniag" the ampoule the monomer and solvent, which had been previously degassed, were re-condensed into it from graduated measurhlg tanks and the initiator added, followed by sealing the ainpouh~. The n-butyl-lithium concentration was 0.02 mole/l, in all experiments, monomer concentration 1.7-2-1 mole/1, and temperature 20°. Isoprene, butadiene, methyl methacrylate, aerylonitrilc and styrene were polymerized with carbanions obtained by reaction of n-butyl-lithium with vinyl-substituted germanium compounds in a device shown in the Figure. The device was connected to a vaeuunl system through section 1 mid a graduated burette containing the working initiator solution was connected to section 2. Ampoule 3 was carehflly ev~euated and "conditioned" and the requisite ~mount of chromatographically pure vinyl-substituted germanium compounds and a solvent previously dcgassed and treated with C2H5Li powder were recondensed. A calculated amount of n-butyl-lithium was then added and the device unsealed at the contracted part 4. After 24 hr when using ~- and fl-styryltrimethylgermanium compounds * Vysokomol. soyed. A13: No. 1, 168-173, 1971. 191
192
N . S. N A M E T K I N et al. T A B L E 1. SOME t'ROPERTIES OF SUBSTITUTED VIiWYL GERMA1WIUSY[ COMPOUI~DS
Compound formula
llame
CH3--CH----CH
I
n-Proponyltrimethylgormane
Boiling point, oC
n~
d~°
101/752
1.4341
1.0045
97.5/747
1.4294
1.0006
57/2.5
1.5365
1.1379
s3/4
1.5425
1.1441
Ge(CH3)3 CH~:C--Ge(CHa)3 Isoproponyltrimethylgermane
CH~=C--Ge(eH~), a-Styryltrimethylgermane
C]6I-I. CH----CI-I--Ge(CIt~).
fl-Styryltrimethylgermane
I
C6H5
and three iso- and n-propenyltrimethylgermauium compounds (preliminary control experiments established that the chromatographically established a m o u n t of free butane after decomposition of the reaction mass with water did not exceed the a m o u n t of butane dissolved in the butyl-lithium before the reaction) the device was connected to the distributive flange of the vacuum apparatus through section 5. After conventional preparation the ampoule was filled with hydrocarbon monomers previously degassed and the solvent and unsealed from the apparatus at the contracted part 7. Then by breaking membrane 9 with hammer 8
4
8 Y
7
Device for polymerization on carbanions obtained by the interaction of substituted vinyl germanium compounds and n-butyl-lithium.
Polymerization transformation of substituted vinyl germ~mium compounds
193
the monomer solution was decanted into the carbanion solution and contra~ted part 10 was rosealed, when ampoule 3 was retained at room temperature for a certain period of time. The monomers were polymerized with carbanions obtained by the reaction of n-butyllithium with substituted vinyl germanium compounds at 20°. n-Butyl-lithium solution was added, in a quantity to ensure a content of 0.005-0.02 mole/l, in the reaction mass, to substituted vinyl germanium compounds dissolved in heptane, of which the concentration was 0.6 1-2 mole/1. In all experiments the amount of substituted vinyl germanium compounds was 30-200 times more than that of n-butyl-lithium. After the initiator had fully reacted, when parallel experiments showed the absene~ of free n-butyl-lithium (chromatographic analysis), the monomers tested (acryh)nitrile, methyl methacrylate, styrene, butadiene and isoprene) were added to the polymerizatiotl systemso that their concentration~vas 1.1 5.9mole/l. The polymers obtained were separated with methanol and mtalysed. RESULTS AND DISCUSSION
As shovnl by a t t e m p t s to polymerize substituted vinyl g~,rmanium compounds (Table 1) with n-butyl-lithium, none of the monomers examined could, under the conditions indicated, be converted into polymer. I t may, however, be concluded from these experiments t h a t initiation apparently takes place fairly readily, which is confirmed by the appearance of colour after adding an initiator to the system. I n the case of a fl-styryltrimethylgermarfium compound the colour is bright red, the a-styryltrimethylgermane gives an orangered tint, the n-propenyltrimethylgermane a yellow tint, isopropenyltrimethylgermane develops no colour. Colour m a y be due to the appearance of earbanions formed b y adding n-butyl-lithium to the monomer molecule. The viscosity of the system did not increase with time, which proves the absence of polymerization. After opening the ampoule, in which polymerization was carried out, the colour disappeared and noticeable quantities of solid or liquid products of polymerization could not be separated. i t appears to us t h a t the absence of polymerization could either be the consequence of sterie hindrance or of the formation of stable adducts incapable of causing polymerization of either their "own", or "foreign" monomers. It is well knowat t h a t the presence of bulky substituents at the double bond is of importance at the stage of chain growth when the ne xt monomer unit is added to the growing carbanion. The second assumption could easily be examined by studying polymerization transformations of several widely used hydrocarbon monomers on carbanions obtained by interaction of substituted vinyl germanium compounds with n-butyllithium (when free initiators are absent from the system). Acrylonitrile, methyl methaerylate, styrene, butadiene, isoprene, were examined i.e. monomers for which polymerization on lithium alkylates has been extensively studied. Results of experiments indicate t hat almost all these monomers, except styrene, readily po]ymerize on carbanions of substituted e-alkenylgermanium compounds. Coltditions of polymerization and characteristics of polymers obtained arc shown in Table 2.
14 15
10 11 12 13
9
Exp. No.
TABLE
Ge(CHs)a
C,HgCH2--C-Li +
HC--C-HLi +
I
I-I~C a
Isoprene Vinyltrimethylsilane
Butadiene Buta~liene Isoprene Isoprene (2-stage addition) Vinyltrimethylsilane Acrylonitrile Methyl methacrylate Styrene Butadiene (2-stage addition)
Acrylonitrile Methyl methacrylate Styrene Butadiene (2-stage addition)
Monomers to be polymerized
OBTAINED
80.0 41.0 39.0 62.0
24-0 24.0 0.5 2-0 48.0 4"56 2-40 4-32
0.74 0-008 0"53 0"013 0'74 0-019 1.03 i 0"016 0-72 0"009
0.7010-018 0.53 i 0-013
0-74 10"009
3.33 2.40
5.1
1"60
20.0 24.0
63.0 48.0
97-0
34.0 98.0 83.0
2"0 24-0 24.0
2"20 2"80 3"30
0.005 0.006 0"018
0"75 0"76 0"70
72.0
99.3
72"0
5-93
0"77 ! 0"005
1"63
37.0 56.0
0'5 2.0
0"74 1 "03 0"72
4'32 1"63 1"60
yield, ~/o
0"019 0.016 0'009
polyvinyl butyl- monomerizagerlithmer tion mane ium polymer-ized time, hr
conc., mole/1.
Reaction conditions
~-SUBSTITUTED
0.12 0.80
0.70
0.83 0.24 0.59 0.52
0.22 0-56 0.18
1.1
0.62 0-41
1.4
6.5
5-3 -1.44 1.40
1-6 4.1 1.6
7-2
1.5 1.3
polymer Ge, vis- wt. ~/o cosity
Characteristics of the polymer
BY THE REACTIOI~ OF g- AND
AND n-BUTYL-LITHIUM
]BY C A R B A N I O N S
M-ETHYLGERMANE
OF MONOMERS INITIATED
Adduct of n-CaHgLi and vinyl germane
2. POLYMERIZATIOI~
1 "08
0"24
1 "60 1.20
0"24
1-50
0"9 0-25
0.12
1-61 1.20
Theoretically calculated Ge, ~o
VINYLTRI-
¢¢
21 22 23 24 25 26 27
20
16 17 18 19
Exp. No.
+
Ge(CH3)3
I
C4H~CH.~--C Li +
I
CH3
Gc(CH3)3
I
CHa--CH--C--HLi
I
Call9
A d d u c t of n-C4HgLi and vinyl germane
Isoprene Vinyltrirncthylsilane Acrylonitrile Methyl methaerylate Styrene Butadiene Isoprene Vinyltrimcthylsilane
Acrylonitrile Methyl methacrylat e Styrene Butadiene
M o n o m e r s to b e polymerized
0.65 0.73 0'62 1-25 0.63 0.61 0.65 0-73 0.62 1.25 0.63 0.61
0.021 0.011 0.021 0.006 0.012 0-019 0.021 0.013 0.021 0.007 0.012 0.019
3.8 2.10 1.84 1.10 3.1 1.9 3-8 1.83 1.84 1.10 3.1 1.9 0"5 2'0 48"0 24'0 24'0 24'0 0'5 2-0 48-0 24-0 84"0 24"0
95'0 74"0 74"0
60"0 40"0 39"0 53"0
76"0
20"0 93'0
0.17 0.26
0.18
0.19 0-21 0.9 0.47
0.I7
0.4 0-6
1.14 1.10
1.71 1-38
1.25 1.08
1-33 1.52
!polyyield, j m e r Ge, ~/o , visco- wt. ] sity
Characteristics of the polymer
polyv i n y l i butyl-~ m o n o m e r m erizagetlithp o l y m e r tion mane iron ized time, hr
cone., mole/1.
Reaction conditions
TABLE 2 (cont.)
0'98 1 '50
1'0
1 "82
1'10 0"92
1"29 1"35
Theoretically calculated Ge, ~/o
c
c
5~
v
c
c
c
196
N.S. NAMETKINet
al.
Analysis shows that the germanium content (experiments 1, 2, 10, 11, 16, 17, 22 and 23) of acrylonitrile-methylmethacrylate polymers obtained using all four carbanions is less than 1.6 °/o (i.e. the macromolecule contains only 1 alkenyl germanium unit). Thus, carbanions of substituted trimethyl germanium compounds only cause the polymerization of acrylonitrile and methyl methacrylate, but do not themselves participate in chain extension. Apparently, carbanions which have a terminal acrylonitrile or methyl methacrylate unit do not incorporate substituted alkenyl germanium compounds either because of weak basicity or, possibly, isomerization of the active end of the polymer chain to form a stable ion, which is unable to continue chain extension [6, 7]. A different pattern was observed with polymerization of butadiene and isoprene oll carbanions obtained from a- and fl-styryltrimethylgermanium coinpounds. On adding dienes to these carbanions the colour gradually disappeared and the viscosity of the system increased at the same time. A control experiment showed that if polymerization of butadiene is discontinued after 2 hr (Table 2, experiment 5) with a diene transformation of 340, the polymer contains only 1.6% germanium, which proves that in the initial stage of the reaction only diene is polymerizcd and the amount of fl-styryltrimethylgermanein the polymer chain is insignificant. In experiments when polymerization was carried out until to complete transformation of diene the colour typical of carbanions reappeared H
I
Li +
I
(CH3)3Ge--CH--C-Li+ or (CH3)3Ge--C---CH~--C4H9
Apparently in this case not only the carbanion formed from fl-styryltrimethylgermanc and n-butyl-lithium adds onto the diene, but also the carbanion which has a diene unit at the end adds on the fl-styryltrimethylgermane, which is confirmed by the appearance of colour. The germanium content in the polymer was 4.1% (Table 2, experiment 6) which corresponds to 5 styryltrimethylgermane units for each 95 units of butadiene contained in the polymer 6hain (with an initial molar ratio of 90 mole % butadiene and 10 mole % fl-styryltrimethylgermane). After addition of more diene to this system, the colour again disappears ~nd the diene added polymerizes. The amount of germanium in the polymer obtained after the second addition of diene increases. A copolymer is obviously formed in this case, but owing to the different rates of adding the monomers--diene and styryltrimethylgermane--to the ends of growing chains the latter, having lower activity, will mainly form part of the polymer chain at the end of polymerization after the diene monomer has almost completely been used in the system, a polymer being formed with alternating
Polymerization transformation of substituted vinyl germanium compounds
197
different monomer units. The viscosity of the copolymers obtained was 1.1 dl/g for polybutadiene and 0.83 dl/g for polyisoprene. The structure of the polybutadiene formed differs little from the structure of this polymer obtained during polymerization initiated with n-butyl-lithium (Table 3). T A B L E 3. S T I t U C T U R E OF I~OLYBUTADIENE OBTAIXED ~*VITI~ VARI:OUS I N I T I A T O R S , A~-~CORDINO
To
II~
sr~c~oscoelc RESULTS Nmnber of units o/ ~o
Polymerization initiator
1,2 n-Butyl-lithium Carbanion offl-styryltrimethylgermane and n-C,I-~Li Carbanion of a-styryltrimethylgermane and n-C4H~Li
7"0 10.5 12.5
I
trans
cis-
45"5 41.5 39'5
47.5 48-0 48"0
When dienes were polymerized on carbanions obtained by the interaction of n-butyl-lithium with methyl-substituted vinyltrimethylgermanium compounds the germanium content of the polymers was less than 1-5% with an almost qfiantitative transformation of diene. Each polydiene macromolecule obviously contains only one organic germanium group (Table 2, experiments 19, 20, 25, 26). Propenyl germanium compounds are apparently of lower activity compared with styryl germanium compounds i.e. earbanions prepared from propenyl germanium only cause polymerization of dienes, but organic germanium monomers do not take part in chain extension. On adding to carbanions substituted vinyl germanium compounds of styrene the colour disappeared immediately, but polymerization does not take place since stable adducts are apparently formed in the system which are unable to cause polymerization either of styrene or of the diene added to the reaction mixture obtained. It should be pointed out that the colour @pical of styrene carbanions was not observed. From results of polymerization transformation of substituted vinyltrimethylgermanium compounds it may be concluded that neither methyl nor phenylsubstituted vinyl germanium compounds polymerize on lithium alkyls, but form carbanions capable of causing polymerization of other monomers. Carbanions obtained from phenyl- and methyl-substituted vinyl germanium compounds differ markedly in activity as regards diene polymerization. If ~- and ~-styryltrimethylgermane form copolymers with dienes, carbanions of methyl-substituted vinyl germane only initiate polymerization of dienes but the propenyl trimethyl germanium compounds themselves do not take part in polymer chain extension. Consequently, the absence of polymerization of substituted vinyl germanium compounds is due to strong steric hindrance caused by the substituents at the multiple bond and the germanium atom. However, the activity of the carbaaions formed also has a certain effect on the processes studied.
A . A . BERLI~¢ et al.
198
CONCLUSIONS
(1) A study was made of polymerization transformations of acrylonitrile, methyl methacrylate, isoprene, butadiene, styrene on carbanions obtained by interaction of n-butyl-lithium and substituted vinyl germanium compounds. (2) It is shown that n-propenyltrimethylgermane, isopropenyltrimethylgermane, ~-styryltrimethylgermane, fl-styryltrimethylgermane form active carbanions, although they themselves do not polymerize with n-butyl-lithium. Translated by E. SEMERE
REFERENCES 1. N. S. NAMETKIN, S. G. DURGAR'YAN, L. I. TIKHONOVA, N. V. USHAKOV and M. V. POZDNYAKOVA, Dokl. AN SSSR 181: 1138, 1968 2. N. S. NAMETKIN, S. G. DURGAR'YAN and L. I. TIKHONOVA, Dokl. AN SSSR 172: 867, 1967 3. V. G. FILIPPOVA, N. S. NAMETKIN and S. G. DURGAR'YAN, Izv. AN SSSR, Otd. khim. n., 1727, 1966 4. N. S. NAMETKIN, S. G. DURGAR'YAN and V. S. KHOTIMSKII, Vysokomol. soyed. Al1: 2067, 1969 (Translated in Polymer Sci. U.S.S.R. 11: 9, 2360, 1969) 5. T. V. TALALAYEVA and K. A. KOCHESHKOV, Zh. organ, khim. 29: 392, 1953 6. R. K. GRAHAM, I. R. PANCHAK and M. I. KAMPF, J. Polymer Sci. 44: 411, 1960 7. P. CLAES and G. SMETS, Makromolek. Chem. 44-46: 212, 1961
STUDY OF THE ABILITY OF OLIGOESTERACRYLATES CONTAINING PHOSPHORUS TO POLYMERIZE* A. A.
BERLIN,
L. P.
RASKINA,
L. A. ZHIL'TSOVA and B. S. EL'TSEFON
All-Union Scientific Research Institute of 5{edicinal Polymers
(Received 14 November 1969)
THE principal relations of three-dimensional polymerization of oligomers have mainly been investigated using oligoesteracrylates (OEA) [1]. Oligoaestererylates able to polymerize and containing sulphur and silicon have recently been studied kinetically [2, 3]. Among the most interesting oligomers capable of polymerizing are the unsaturated oligoalkylphosphinates, which on copolymerization with conventional oligoestcracrylates or other unsaturated compounds produce fire-resistant polymers. However, there is no information in the literature concerning the polymerization ability of oligomers containing phosphorus. * Vysokomol. soyed. A13: :No. 1, 174-182, 1971.