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Polymerization of hepta-1,5-diene on complex catalysts
1424
L. M. ROMANOVet al.
10. K. A. PETROV, G. A. SOKOL'SKIIand B. M. POLES, Zh. obshch, khim. 26 : 3381, 1956 l l. B. SAUNDERS, Khimiya i toksikologiya organieheskikh soyedinenii fosfora i ftora. (Translation of: Some Aspects of the Chemistry and Toxic Action of Organic Compounds Containing Phosphorus and Fluorine.) Foreign Literature Publishing House, 1961 12. L. LITTHAUER, Ber. dtseh, chem. Gcs. 22 : 2144, 1889
POLYMERIZATION OF HEPTA-1,5-DIENE ON COMPLEX CATALYSTS * L.M. ROMANOV, A.P. VERKHOTUROVA, YU. V. KISSIN and G.V. ~AKOVA Institute of Chemical Physics, U.S.S.R. Academy of Sciences (Received 2 November 1961)
THE difficulty of obtaining vulcanizable rubbers by the copolymerization of a-olefins consists mainly in the method of introducing double bonds into the copolymer. Attempts to synthesize a polymer of this type from ethylene or propylene with the addition of acetylene or diene hydrocarbons have been unsuccessful [1-3]. I t seemed to ~s to be possible to obtain the desired polymer by the copolymerization of ~-olefins with non-conjugated dienes containing both internal and external double bonds. I t was assumed t h a t the external double bonds would take part in the polymerization and the unreactive internal double bonds would remain unaffected. As the subject of investigation, we selected hepta-l,5-diene. The first stage of the work consisted in a study of the homopolymerization of hepta-l,5-diene in solution under the influence of catalysts of the Ziegler-Natta type. At the present time, it is known t h a t in the presence of Ziegler-Natta catalysts, compounds containing two non-conjugated vinyl groups give polymers consisting of cyclic units [5. 6].
So far as concerns compounds with internal and external double bonds, their behaviour under such conditions has not been studied t * Vysokomol. soye4. 5: No. 5, 719-723, 1963. ¢ While this work was being carried out, a communication from Natta appeared showing that an internal double bond is capable of taking part in polymerization of the anion-coordination type [4].
Polymerization of hepta-l,5-diene on complex catalysts
1425
The p o l y m e r i z a t i o n o f the h e p t a - l , 5 - d i e n e was carried o u t in solution in n-heptane at 70-80 ° in the presence of the following c a t a l y t i c systems: AI(C~Hs)3Ti(OCdH9)4; LiCdI-Ig-TiC14; AI(C2Hs)3-TiC14; AI(/~o-CdHg)3-TiCI4; a n d AI(C~Hs) 3TiC13. The first two s y s t e m s proved to be incapable o f initiating the p o l y m e r i z a t i o n process, a n d the s y s t e m c o n t a i n i n g Al(iso-CdH~) 3 (ratio of A1 to Ti = 2 . 1 ) to h a v e a low efficiency, the yield of p o l y m e r a m o u n t i n g to 1 - 5 % . The best results were o b t a i n e d with the s y s t e m AI(C~Hs)8-TiCI4. I t was established t h a t the ratio o f the c o m p o n e n t s of the c a t a l y s t has a f u n d a m e n t a l effect on the yield o f polymer. As the A1 : Ti m o l a r ratio was increased, the yield o f p o l y m e r rose, reaching a m a x i m u m figure (40 %) at a 2 : 1 ratio. A f u r t h e r increase in the A1 : Ti ratio led to a fall in the yield o f p o l y m e r * (Table l, Fig. 1). TABLE 1. POLYMERIZATION OF HEPTA-1,5-DIENE ON AI(C2H5)3-TiC14 CATALYTIC SYSTEMS
Hepta1,5-diane, g
4-3 4-3 1.0 1-0 1.0 1.0 1-0
1.0 1.0 1.0
Catatyst c}~ by weight Molar ratio Heptaof the A1 (Calls) a : he, ml monoTiCI4 mar 3'0 3'0 1.7 3.4 3.7 3.4 4.3 2.8 2.7 2-7
1:1 1:1 1.2:1 1-2:1 1.5:1 1.7:1 2:1 3:1 3:1 3:1
24 24 4 3 2 2 2 4 3 3
Temperature, °C
80 80 70 80 80 80 80 70 80 ' Room
Polymerization time, hours 8
50 70 50 15 15 15 70 50 100
Yi:14,
Yo
Unsaturation, ~o
1 1
16 16 32 36 40 9 6 1
28.9 25.6 22-4 28.0 16.7 27.5 14.0
3O
10 I
t
2
3
At(C2Hs)3-riCt4 FI~. 1. Yield of hepta-l,5-diene polymer as a function of the composition of the AI(C~Hs)3-TiCI~catalyst. * On working with different batches of AI(C2H~)8 the absolute yield of polymer for a given ratio varied, but the general nature of the dependence of the conversion on the composition of the catalyst remained the same.
1426
L. M. ROMANOVet al.
Polyhepta-1,5-diene consists of a transparent rubber-like product with a refractive index of n~ 1.5077, soluble in heptane, benzene, chloroform, tetralin, etc. The molecular weight of the polymer, determined ebullioscopically was 1250, while for a repeatedly reprecipitated sample it was 1750. The intrinsic viscosity in tetralin was 0.09 dl/g. The content of double bonds in the polyhepta-l,5-diene, determined by Hanus's method varied between 25 and 30%. The results of chemical analysis agreed quite well with the results obtained by I R spectroscopy. The I R spectra of polyhepta-l,5-diene were recorded in the 2000-700 cm -1 region on a IKS-14 instrument. The samples for investigation were obtained b y depositing a thin film of the viscous polymer on an NaC1 window. The spectrum of the monomer was taken at a cuvette thickness of 50/~. The spectra of hepta-l,5-diene and its polymer are given in Fig. 2.
a
1437
377
983908
b
J
1310
882
FIG. 2. IR spectra: a--hepta-l,5-diene; b--polyhepta-l,5-diene. An interpretation of the spectra was carried out on the basis of literature data and comparison with the spectra of various polymers of ~-olefins. It must be mentioned that the absorption band at 725 cm -1 (deformation vibrations of several successive CH~ groups) is low as compared with literature data [7]. However, the same band exists in the spectrum of poly-n-amylene which also has only two CHH~ groups arranged in a sequence [8]. In order to determine the content of double bonds in the polyhepta-l,5-diene, we had recourse to the method of an internal standard, i.e. we used not the absolute optical densities of the bands of unsaturation b u t their ratio to the optical density of the 1448 cm -1 band. Thus, the amount of double bonds per CI-I~ group in the polymer was calculated with account taken of the appearance of additional CHt~ groups, in comparison with the monomer, b y the opening of double bonds in the course of polymerization, This method is quite accurate since the change
Polymerization of hepta-l,5-diene on complex catalysts
1427
in the coefficients of the various bands on passing from the monomer to the polymer can be considered small. Results of the determination of the double bonds in the polyhepta-l,5-diene are given in Table 2. TABLE 2. DETERMINATION OF I)OUBLE BONDS IN POLYHEPTA-1,5-1)IENE
Density Substance
I D144s
Hepta-l,5-diene Polyhepta- 1,5-diene Polyhepta-l,5-diene with the lowest molecular weight*
D9~4
~
D964
Content, ~o of D9n
Internal C= C D14~s I bonds
I)911 - -
Vinyl bonds
0.854 1.184 0.913 0.730
1.39 0.80
1.202 0.110
1.41 0.12
100 66
100 14
0.367 0.387
1.05
0.042
0.11
100
13
* Isolated from sohltion after the precipitation of the bulk of the polymer.
From the results obtained it may be concluded t h a t an internal double bond may take part in polymerization initiated by a catalyst of the Ziegler-Natta type, although to a slight extent. In fact, this process may be considered as a copolymerization of the internal double bonds with the external ones present in the same molecule of the monomer. Since the polymer is soluble in organic solvents, the internal double bonds are used up not in cross-linking but in the formati9n of rings in the polymer chain. Thus, it is possible to deduce the structure of polyhepta-l,5-diene. The polymer consists on an average of 12-13 monomer units connected to one another through the opening of the vinyl groups and containing two types of units -- 5-membered rings and branches with an internal double bond. CH2 CH 2 - CH-- CH-- H C ~ C H
I
I
I
CH2 CH:~H~C CH2 I
I
-- CH 2-- CH
CH2
I
CH~ CH 2
cH I] CH
CH Ir CH
CHa
CH~
:
i
in a ratio of approximately 1 : 2, (see Table 2). In addition, the molecule contains only two vinyl double bonds, as is confirmed by the ozonization of the polyhepta1,5-diene, as well as by the I R spectra. Analysis of the decomposition products of the ozonide of the polymer showed the presence of formaldehyde and acetaldehyde in a ratio of 1:4. The presence of vinyl groups in the polymer may be explained by an isomerization of the allyl type which (in the reverse order)takes place in the polymerization of non-conjugated dienes, in particular hexa-l,5-diene [5],
1428
L . M . ROMANOVet al.
which we have also investigated for comparison with polyhepta-l,5-diene. The absence of a band at 890 cm -1 in the spectrum of the polymer indicates that there are no vinylidene groups in the polymer and, consequently, that the rupture of the chain takes place not at the stage of A1--CH2--CHR-- but at the stage CH2 A1--CH--HCI ~//X')C H CH a H 2 C - - - C H ~
In this process, the formation of both external and internal double bonds is probable CH~ CH 2 CH~--CH--HC~CH
F
or C H a - - C H : C ~ C H
f
H2C---CH z
I
I
HaC--CH z
It is possible that one of the vinyl groups present in the molecule of polyhepta1,5-diene is formed in just this way. EXPERIMENTAL Hepta-l,5-die~e was obtained by an organomagnesium synthesis from crotyl chloride and allyl chloride in absolute ether at 0 ° [9]. The resulting mixbure of diene hydrocarbons was fractionated in a rectifying column with a nichrome packing (height 150 cm). The hepta-l,5-diene had b.p. 93"4 ° (according to literature data 93.7°). The m o n o m er was stored in sealed tubes over metallic sodium. Catalyst. Purification of TiC14 was carried out by boiling over powdered copper for 12 hours, after which the TiCla was distilled in a current of dry argon at atmospheric pressure. A solution of TiC14 in heptane was prepared in au argon chamber. To prepare the solution of AI(CaHs) s in heptane we used AI(CsHs) a redistilled in v a c u u m (b.p. 96°/1 ram). The n-heptane used was spectroscopically pure. The purity of the heptane was checked by means of the absorption spectrmn taken in a SF-4 speetrophotometer in the 220-230 m~ region. The polymerization of hepta-l,5-diene was carried out in two-compartment tubes which were filled in a vacuum apparatus. The required a m o u n t of monomer and solvent was introduced into one part of the tube and the components of the catalysV were measured into the other part. To start the polymerization, the monomer and catalyst were mixed by breaking the partition of the tube. During polymerization in an air thermostat, the contents of the tube were continuously agitated. The polymer was precipitated and washed free of catalyst with an excess of methanol. The washed polymer was reprecipitated from benzene and dried to constant weight in vacuum. Determination of the double bo~ds in the polymer was carried out by iodination with Hanus's reagent. Ozonization of the hepta-l,5-diene polymer obtained was carried out in solution in CCI4. The products of the hydrolysis of the ozonides were separated by paper chromatography *. The main absorption bandz i~ the I R spectra of hepta-l,5.diene, hexa-l,5-diene, and their polymers and the assignment of these bands to the appropriate groups are given in Table 3. * The authors express their thanks to G. Ye. Zaikov for help in the analysis of the ozonization products of the polyhepta-l,5-diene.
1429
P o l y m e r i z a t i o n of h e p t a - l , 5 - d i e n e o n c o m p l e x c a t a l y s t s TABLE 3. BANDS (cm-~) OF THE ~P~ ABSORPTION SPECTRA OF tIEPTA-1,5-DIENE, HEXA-1,5-DIENE, AND THEIR POLYMERS
H e p t a - 1,5diene
Polyhepta1,5-4iene
Hexa1,5-4iene
Polyhexa1,5-diene
Notes
1825 m. 1638 s. 1437 s.
1660 m.-w. 1448 s.
1836 s.f. 1647 s. 1440 s.
1825 m. 1645 s.-m. 1448 s.
O v e r t o n e 907 era -~ C--C bond stretching vibration D e f o r m a t i o n v i b r a t i o n of CH~ groups
1420 i. 1377 m.
1408 w. 1377 s.
1419 s.-i.
1415 i. 1373 w.
1297 m.-w. 1240 m.-w. 1120 w. 1073 w. 992 963 908 856
s.i. s. s. w.
1348 1310 1235 1160 1124 1060 1028
w.-i. w. w.
1344 w. 1305 m. 1244 w.
w.
1193 w. 1028 w.
s. w.
908 837 w. 776 w.
w.
CH 3
--CH=CH~
992 m . 966 w.-m. 907 s.
992 s. 964 911 861 823 773 676 725
D e f o r m a t i o n v i b r a t i o n of groups
lrans--CH
CH--
--CH=CH~
752 w.
w. s.-m.
Deformation vibrations (CH2)
676 w.
700 m.i. Note. Symbols for band intensities: s.-strong; w.--weak; nl,--medium; i.--infleetion.
CONCLUSIONS (1) T h e p o l y m e r i z a t i o n action of the catalytic
of hepta-l,5-diene
system
(2) A n i n t e r n a l
d o u b l e b o n d is c a p a b l e
(3) A s t r u c t u r e
of polyhepta-l,5-diene
chemical
and spectroscopic
in solution in n-heptane
under
the
AI(C~Hs)a-TiCI 4 has been carried out. of taking has
analyses.
part in polymerization.
been
proposed
on the
basis
of
Translated by B. J . HAZZARI)
REFERENCES l. G. NATTA, G. M A Z Z A N T I a n d G. BOSCH[, I t a l . P a t . 565323, 1957; Chem. A b s t r . 5 3 : 1959 2. G. NATTA, G. C R E S P I a n d G. BORSINI, I t a l . P a t . 574913, 1958; C h e m . A b s t r . 53 : 1959 3. N. S. VOLKOVA, G. V. K H U T A R O V A , B. A. K R E N T S E L ' , Z. A. ROGOVIN a n d A. V. TOPCHIEV, V y s o k o m o l . soyed. 1 : 1758, 1959 4. G. NATTA, M a k r o m o l . Chem. 35 : 94, 1960 5. C. S. M A R V E L a n d I. K. STILL, J . A m e r . C h e m . Soc. 80 : 1740, 1958 6. C. S. M A R V E L a n d W . E. GARRISON, J . A m e r . C h e m . Soc. 81 : 4737, 1959 7. H. L. M c M U R R Y a n d V. THORNTON, A n a l . C h e m . 24 : 318, 1952 8. M. P. B E R D N I K O V A , Yu. V. KISSIN a n d N. M. CHIRKOV, V y s o k o m o l . soyed. 4 : 63, 1962 9. A. L. H E N N E , H. CHANON a n d A. T U R K , J . A m e r . C h e m . Soe. 63 : 3474, 1941
L. M. ROMANOVet al.
10. K. A. PETROV, G. A. SOKOL'SKIIand B. M. POLES, Zh. obshch, khim. 26 : 3381, 1956 l l. B. SAUNDERS, Khimiya i toksikologiya organieheskikh soyedinenii fosfora i ftora. (Translation of: Some Aspects of the Chemistry and Toxic Action of Organic Compounds Containing Phosphorus and Fluorine.) Foreign Literature Publishing House, 1961 12. L. LITTHAUER, Ber. dtseh, chem. Gcs. 22 : 2144, 1889
POLYMERIZATION OF HEPTA-1,5-DIENE ON COMPLEX CATALYSTS * L.M. ROMANOV, A.P. VERKHOTUROVA, YU. V. KISSIN and G.V. ~AKOVA Institute of Chemical Physics, U.S.S.R. Academy of Sciences (Received 2 November 1961)
THE difficulty of obtaining vulcanizable rubbers by the copolymerization of a-olefins consists mainly in the method of introducing double bonds into the copolymer. Attempts to synthesize a polymer of this type from ethylene or propylene with the addition of acetylene or diene hydrocarbons have been unsuccessful [1-3]. I t seemed to ~s to be possible to obtain the desired polymer by the copolymerization of ~-olefins with non-conjugated dienes containing both internal and external double bonds. I t was assumed t h a t the external double bonds would take part in the polymerization and the unreactive internal double bonds would remain unaffected. As the subject of investigation, we selected hepta-l,5-diene. The first stage of the work consisted in a study of the homopolymerization of hepta-l,5-diene in solution under the influence of catalysts of the Ziegler-Natta type. At the present time, it is known t h a t in the presence of Ziegler-Natta catalysts, compounds containing two non-conjugated vinyl groups give polymers consisting of cyclic units [5. 6].
So far as concerns compounds with internal and external double bonds, their behaviour under such conditions has not been studied t * Vysokomol. soye4. 5: No. 5, 719-723, 1963. ¢ While this work was being carried out, a communication from Natta appeared showing that an internal double bond is capable of taking part in polymerization of the anion-coordination type [4].
Polymerization of hepta-l,5-diene on complex catalysts
1425
The p o l y m e r i z a t i o n o f the h e p t a - l , 5 - d i e n e was carried o u t in solution in n-heptane at 70-80 ° in the presence of the following c a t a l y t i c systems: AI(C~Hs)3Ti(OCdH9)4; LiCdI-Ig-TiC14; AI(C2Hs)3-TiC14; AI(/~o-CdHg)3-TiCI4; a n d AI(C~Hs) 3TiC13. The first two s y s t e m s proved to be incapable o f initiating the p o l y m e r i z a t i o n process, a n d the s y s t e m c o n t a i n i n g Al(iso-CdH~) 3 (ratio of A1 to Ti = 2 . 1 ) to h a v e a low efficiency, the yield of p o l y m e r a m o u n t i n g to 1 - 5 % . The best results were o b t a i n e d with the s y s t e m AI(C~Hs)8-TiCI4. I t was established t h a t the ratio o f the c o m p o n e n t s of the c a t a l y s t has a f u n d a m e n t a l effect on the yield o f polymer. As the A1 : Ti m o l a r ratio was increased, the yield o f p o l y m e r rose, reaching a m a x i m u m figure (40 %) at a 2 : 1 ratio. A f u r t h e r increase in the A1 : Ti ratio led to a fall in the yield o f p o l y m e r * (Table l, Fig. 1). TABLE 1. POLYMERIZATION OF HEPTA-1,5-DIENE ON AI(C2H5)3-TiC14 CATALYTIC SYSTEMS
Hepta1,5-diane, g
4-3 4-3 1.0 1-0 1.0 1.0 1-0
1.0 1.0 1.0
Catatyst c}~ by weight Molar ratio Heptaof the A1 (Calls) a : he, ml monoTiCI4 mar 3'0 3'0 1.7 3.4 3.7 3.4 4.3 2.8 2.7 2-7
1:1 1:1 1.2:1 1-2:1 1.5:1 1.7:1 2:1 3:1 3:1 3:1
24 24 4 3 2 2 2 4 3 3
Temperature, °C
80 80 70 80 80 80 80 70 80 ' Room
Polymerization time, hours 8
50 70 50 15 15 15 70 50 100
Yi:14,
Yo
Unsaturation, ~o
1 1
16 16 32 36 40 9 6 1
28.9 25.6 22-4 28.0 16.7 27.5 14.0
3O
10 I
t
2
3
At(C2Hs)3-riCt4 FI~. 1. Yield of hepta-l,5-diene polymer as a function of the composition of the AI(C~Hs)3-TiCI~catalyst. * On working with different batches of AI(C2H~)8 the absolute yield of polymer for a given ratio varied, but the general nature of the dependence of the conversion on the composition of the catalyst remained the same.
1426
L. M. ROMANOVet al.
Polyhepta-1,5-diene consists of a transparent rubber-like product with a refractive index of n~ 1.5077, soluble in heptane, benzene, chloroform, tetralin, etc. The molecular weight of the polymer, determined ebullioscopically was 1250, while for a repeatedly reprecipitated sample it was 1750. The intrinsic viscosity in tetralin was 0.09 dl/g. The content of double bonds in the polyhepta-l,5-diene, determined by Hanus's method varied between 25 and 30%. The results of chemical analysis agreed quite well with the results obtained by I R spectroscopy. The I R spectra of polyhepta-l,5-diene were recorded in the 2000-700 cm -1 region on a IKS-14 instrument. The samples for investigation were obtained b y depositing a thin film of the viscous polymer on an NaC1 window. The spectrum of the monomer was taken at a cuvette thickness of 50/~. The spectra of hepta-l,5-diene and its polymer are given in Fig. 2.
a
1437
377
983908
b
J
1310
882
FIG. 2. IR spectra: a--hepta-l,5-diene; b--polyhepta-l,5-diene. An interpretation of the spectra was carried out on the basis of literature data and comparison with the spectra of various polymers of ~-olefins. It must be mentioned that the absorption band at 725 cm -1 (deformation vibrations of several successive CH~ groups) is low as compared with literature data [7]. However, the same band exists in the spectrum of poly-n-amylene which also has only two CHH~ groups arranged in a sequence [8]. In order to determine the content of double bonds in the polyhepta-l,5-diene, we had recourse to the method of an internal standard, i.e. we used not the absolute optical densities of the bands of unsaturation b u t their ratio to the optical density of the 1448 cm -1 band. Thus, the amount of double bonds per CI-I~ group in the polymer was calculated with account taken of the appearance of additional CHt~ groups, in comparison with the monomer, b y the opening of double bonds in the course of polymerization, This method is quite accurate since the change
Polymerization of hepta-l,5-diene on complex catalysts
1427
in the coefficients of the various bands on passing from the monomer to the polymer can be considered small. Results of the determination of the double bonds in the polyhepta-l,5-diene are given in Table 2. TABLE 2. DETERMINATION OF I)OUBLE BONDS IN POLYHEPTA-1,5-1)IENE
Density Substance
I D144s
Hepta-l,5-diene Polyhepta- 1,5-diene Polyhepta-l,5-diene with the lowest molecular weight*
D9~4
~
D964
Content, ~o of D9n
Internal C= C D14~s I bonds
I)911 - -
Vinyl bonds
0.854 1.184 0.913 0.730
1.39 0.80
1.202 0.110
1.41 0.12
100 66
100 14
0.367 0.387
1.05
0.042
0.11
100
13
* Isolated from sohltion after the precipitation of the bulk of the polymer.
From the results obtained it may be concluded t h a t an internal double bond may take part in polymerization initiated by a catalyst of the Ziegler-Natta type, although to a slight extent. In fact, this process may be considered as a copolymerization of the internal double bonds with the external ones present in the same molecule of the monomer. Since the polymer is soluble in organic solvents, the internal double bonds are used up not in cross-linking but in the formati9n of rings in the polymer chain. Thus, it is possible to deduce the structure of polyhepta-l,5-diene. The polymer consists on an average of 12-13 monomer units connected to one another through the opening of the vinyl groups and containing two types of units -- 5-membered rings and branches with an internal double bond. CH2 CH 2 - CH-- CH-- H C ~ C H
I
I
I
CH2 CH:~H~C CH2 I
I
-- CH 2-- CH
CH2
I
CH~ CH 2
cH I] CH
CH Ir CH
CHa
CH~
:
i
in a ratio of approximately 1 : 2, (see Table 2). In addition, the molecule contains only two vinyl double bonds, as is confirmed by the ozonization of the polyhepta1,5-diene, as well as by the I R spectra. Analysis of the decomposition products of the ozonide of the polymer showed the presence of formaldehyde and acetaldehyde in a ratio of 1:4. The presence of vinyl groups in the polymer may be explained by an isomerization of the allyl type which (in the reverse order)takes place in the polymerization of non-conjugated dienes, in particular hexa-l,5-diene [5],
1428
L . M . ROMANOVet al.
which we have also investigated for comparison with polyhepta-l,5-diene. The absence of a band at 890 cm -1 in the spectrum of the polymer indicates that there are no vinylidene groups in the polymer and, consequently, that the rupture of the chain takes place not at the stage of A1--CH2--CHR-- but at the stage CH2 A1--CH--HCI ~//X')C H CH a H 2 C - - - C H ~
In this process, the formation of both external and internal double bonds is probable CH~ CH 2 CH~--CH--HC~CH
F
or C H a - - C H : C ~ C H
f
H2C---CH z
I
I
HaC--CH z
It is possible that one of the vinyl groups present in the molecule of polyhepta1,5-diene is formed in just this way. EXPERIMENTAL Hepta-l,5-die~e was obtained by an organomagnesium synthesis from crotyl chloride and allyl chloride in absolute ether at 0 ° [9]. The resulting mixbure of diene hydrocarbons was fractionated in a rectifying column with a nichrome packing (height 150 cm). The hepta-l,5-diene had b.p. 93"4 ° (according to literature data 93.7°). The m o n o m er was stored in sealed tubes over metallic sodium. Catalyst. Purification of TiC14 was carried out by boiling over powdered copper for 12 hours, after which the TiCla was distilled in a current of dry argon at atmospheric pressure. A solution of TiC14 in heptane was prepared in au argon chamber. To prepare the solution of AI(CaHs) s in heptane we used AI(CsHs) a redistilled in v a c u u m (b.p. 96°/1 ram). The n-heptane used was spectroscopically pure. The purity of the heptane was checked by means of the absorption spectrmn taken in a SF-4 speetrophotometer in the 220-230 m~ region. The polymerization of hepta-l,5-diene was carried out in two-compartment tubes which were filled in a vacuum apparatus. The required a m o u n t of monomer and solvent was introduced into one part of the tube and the components of the catalysV were measured into the other part. To start the polymerization, the monomer and catalyst were mixed by breaking the partition of the tube. During polymerization in an air thermostat, the contents of the tube were continuously agitated. The polymer was precipitated and washed free of catalyst with an excess of methanol. The washed polymer was reprecipitated from benzene and dried to constant weight in vacuum. Determination of the double bo~ds in the polymer was carried out by iodination with Hanus's reagent. Ozonization of the hepta-l,5-diene polymer obtained was carried out in solution in CCI4. The products of the hydrolysis of the ozonides were separated by paper chromatography *. The main absorption bandz i~ the I R spectra of hepta-l,5.diene, hexa-l,5-diene, and their polymers and the assignment of these bands to the appropriate groups are given in Table 3. * The authors express their thanks to G. Ye. Zaikov for help in the analysis of the ozonization products of the polyhepta-l,5-diene.
1429
P o l y m e r i z a t i o n of h e p t a - l , 5 - d i e n e o n c o m p l e x c a t a l y s t s TABLE 3. BANDS (cm-~) OF THE ~P~ ABSORPTION SPECTRA OF tIEPTA-1,5-DIENE, HEXA-1,5-DIENE, AND THEIR POLYMERS
H e p t a - 1,5diene
Polyhepta1,5-4iene
Hexa1,5-4iene
Polyhexa1,5-diene
Notes
1825 m. 1638 s. 1437 s.
1660 m.-w. 1448 s.
1836 s.f. 1647 s. 1440 s.
1825 m. 1645 s.-m. 1448 s.
O v e r t o n e 907 era -~ C--C bond stretching vibration D e f o r m a t i o n v i b r a t i o n of CH~ groups
1420 i. 1377 m.
1408 w. 1377 s.
1419 s.-i.
1415 i. 1373 w.
1297 m.-w. 1240 m.-w. 1120 w. 1073 w. 992 963 908 856
s.i. s. s. w.
1348 1310 1235 1160 1124 1060 1028
w.-i. w. w.
1344 w. 1305 m. 1244 w.
w.
1193 w. 1028 w.
s. w.
908 837 w. 776 w.
w.
CH 3
--CH=CH~
992 m . 966 w.-m. 907 s.
992 s. 964 911 861 823 773 676 725
D e f o r m a t i o n v i b r a t i o n of groups
lrans--CH
CH--
--CH=CH~
752 w.
w. s.-m.
Deformation vibrations (CH2)
676 w.
700 m.i. Note. Symbols for band intensities: s.-strong; w.--weak; nl,--medium; i.--infleetion.
CONCLUSIONS (1) T h e p o l y m e r i z a t i o n action of the catalytic
of hepta-l,5-diene
system
(2) A n i n t e r n a l
d o u b l e b o n d is c a p a b l e
(3) A s t r u c t u r e
of polyhepta-l,5-diene
chemical
and spectroscopic
in solution in n-heptane
under
the
AI(C~Hs)a-TiCI 4 has been carried out. of taking has
analyses.
part in polymerization.
been
proposed
on the
basis
of
Translated by B. J . HAZZARI)
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