Copolymerization of butadiene with propene catalysed by systems containing tribenzyltitanium

1399

Copolymerization: of buta/:lielie with propene 11. 12. 13. 14.

R. W. SEYMOUR and S. L. COOPER, Macromolecules 6: 48, 1973 R. W. SEYMOUR and S. L. COOPER, J. Polym. Sci. 9: 689, 1971 J. C. WEST and S. L. COOPER, J. Polym. Sci. Polym. Syrup. Ed. 60: 127, 1977 A. R. CAIN, Polym. Preprints 17: 576, 1976

Polymer Science U.S.S.R. Vol. 31, No. 6, pp. 1399-1406. 1989 Printed in Poland

0032-3950/89 $ I 0.00 + .00 ~) 1990 Pergamons Press plc

COPOLYMERIZATION OF BUTADIENE WITH PROPENE CATALYSED BY SYSTEMS CONTAINING TRIBENZYLTITANIUM* L. V. SM1RNOVA, L. A. YATSENKO, A. G. BOLDYREV, N . A. VENEDIKTOVAa n d YE. N. KROPACItEVA S. V. Lebedev All-Union Research Institute of Synthetic Rubber (Received 22 December 1987) Copolymerization of butadiene with propene was studied, catalysed by systems conraining (CoH~CH2)3Ti and either alkyl aluminium halogenides or Ti (IV) compounds, and EPR spectra of the catalytically active systems were measured. Depending on the components of the catalytic system and on the conditions employed for the preparation of the catalytic complex, the resulting c0polymers are either alternating with equimolar amounts of propene and butadiene, or containing one monomer in excess. The character of EPR spectra correlates with the results of copolymerization. e

IT is the aim of this study of elucidate the c o m p o s i t i o n of those complexes c o n t a i n i n g T i ( [ l l ) c o m p o u n d s that are c a p a b l e to initiate a l t e r n a t i n g c o p o l y m e r i z a t i o n o f b u t a diene a n d propene. Systems used as c o p o l y m e r i z a t i o n catalysts c o n t a i n e d (C6HsCH2)3Ti and

either

alkyl

a l u m i n i u m h a l o g e n i d e s - ( i s o - C 4 H 9 ) 2 A 1 C l , (iso-C4Hg)I.sAICI~.5,

is:o-C4H,jA1Cl2, (C2Hs)2AICI, (C2Hs)I.sA1CI~. 5 - or Ti(IV) c o m p o u n d s - (CHa)3SiCH2" •TiCI3, C a H s T i C l a , TiCI4. The experiments were carried out with the usual precautions required for work with organometallic compounds and followed the method described in [1]. (C6H~CH2),~Ti, (C6H~CH2)aTi, and (C6HzCHz)3-,,TiCIn (n= 1, 2) were prepared by the usual methods, described in the respective references [2-4]. C3H~TiCI3 was prepared similarly as in [5], except for the stage which involved the isolation of the final product as a complex with. dipyridil. (CH3)3SiCH2TiCI3 and [(CH3)3SiCH213Ti were also studied. '} EPR spectra were registered on the instrument RE-1307 by the method of [6]. * Vysokomo]. soyed. A31: No. 6, 1276-1282, 1989. t Thanks are due to L. I. Vyshinskaya and S. Ya. Timoshenko for providing these compounds.

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TABLE1. ANALYSISOF PRODUCTSOFREACTIONRETWEENTRiBItNZYLTITANIUMANDHYDROGENCHLORIDE 1NTOLUENE,HCI : (C6HsCH2)aTi = 1 oR 2 /

Total Ti content, mole/l. 0.053 0.050

Amount of Ti a+ I Amount of Ti*+ Chlorine content, ] Amount of Ti- C g-equiv./mole I bonds per 1 mole mole/l. R3-,TiCI~ 0.051 0 0.049 [ 2.09 0.052 0 0.104 I 0.96

The composition of reaction products is in Table 1 and indicates that-depending on the ratio of the starting c o m p o n e n t s - t h e reaction between (C~HsCH2)aTi and hydrogen chioride leads to the formation of tribenzyititanium m o n o - O r dichlorides (Table 1). ~ ~: However, the spectra in Fig. 1 demonstrate that the'product is a mixture of several compounds of the type (C6HsCH2)a-nTiCln (n = 0 to 3). The signal of the starting tribenzyltitanium has 91=1"986 [7-9]. Spectrum of the product of reaction between (C6HsCH2)3Ti and HCI (with the ratio CI : Ti ranging from 0.3 to I) consists of three broad lines with 91 = 1.986, 02= 1.965 and 03= 1.945. When the temperature is varied from - 7 8 ° C to - 3 0 ° C (at C! : T i = l ) , the spectral lines preserve their position but the relative integrated intensities change. This shows that the spectrum is not a single signal, of complex structure but consists of three separate components. The position of the signals #2 and #3 and their variation observed when the ratio HCl : (C6HsCH2)3Ti was changed fiom 0.3 to 4 enabled us to assign them to the mono- and dichloride, respectively; the signal with #'4= 1.937 was assigned to TiCIa [10]. In the presence of the catalytic system consisting of (CeHsCH2)aTi and (iso-C,H9)2" •A1CI (I) (at AI : T i = 1) the main product of copolymerization is essentially polybutadiene containing only traces of propylene units, the content od 1,2 units being 57~o (Table 2, experiment 1); on the other hand, in the absence of propene the resulting polybutadien¢ contains 38~o of 1,2-, 2 2 ~ of t r a n s - l , 4 , and 4 0 ~ of c i s - l , 4 units [4]. At the latio (iso-C,H9)2AICI : (C6HsCH2)aTi = 2 the relative reactivity of propene increases and the dyads (C,H6-CsH~)n are formed (Table 2, experiment 2). In the EPR spectra of reaction products prepared with the ratio AI : Ti= 2, in addition to the known signals characteristic for R3Ti (i.e,, signals 0~, g'l, a'~'), new signals appear with g5 = 1.974 and g6 = 1.952. The total concentration of reaction products is about 1 0 ~ fi'om the starting concentration of tribenzyltitanium. Experimentswith copolymetization of propene a n d butadiene in the presence of the system (C6HsCH2)3Ti-(iso-C4H9)~.sAICla.s (II)have shown t h a t - i n contrast to system I - t h e alternating sequences (C4H6"C3H6) are formed also when the ratio of components equals unity (Table 2, experiment 4). The signal with g s = 1.974 appears in the EPR spectrum of the catalytic system under these conditions; the signal with g~ = 1.986, corresponding to (C6HsCH2)3Ti, is about three-times more intensive than that with g s = 1.974 (Fig. 2 spectrum 2). With the ratio (iso-C4H9)~.sAIClt.s : : (C6H~CH2)3Ti is raised to 2, the selectivity of the system with regard to the formation

Copolymerization of butadiene with propene

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of the dyads (C4~--I6-C3H6) increases sharply (Table 2, experiment 5). It is worth mentioning that an increase of ieaction temperature to - 15°C raises the content of dyads in the copolymer to 9 6 ~ (Table 3, experiment 6); g5 = 1.974 is then the t'undamental signal in the EPR spectrum (Fig. 2, spectrum 3). The amount of paramagnetic particles is some 59/0 from the initial amount of (C6HsCHz)3Ti. Weak signals (with intensity of some 3 ~o from the ~ignal g5 = 1.974) are present in the region of trialkyl titanium derivatives. The intensity of the signal g6 increases with reaction time at the expense of signal gs. Increasing the time of contact (at -15°C) between the components of the catalytic system from 1 to 67 hr practically does not influence the content of butadiene-propene dyads (Table 2, experiments 6 to 8). A precipitate inactive in polymerization and containing some 4 ~ from the original content of Ti is gradually formed in the reacting catalytic system, (Table 2, experiment 10). When the copolymerization was catalysed by the system (C6HsCH2)3Ti-iso-C4Hg" •AICI2 (Ill) at AI:Ti= 1, the reaction product, contained propylene sequences as in

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FIG. 1 FIG. 2 FIG. 1. EPR spectra of tribenzyltitanium (1) and of products of its reaction with hydrogen chloride. Ratio HCI: (C6HsCH2)3Ti=0'3 (2), 1 (3), 1.5 (4), 2 (5), and 4 (6) in toluene; concentration of (C~HsCHz)3Ti 0"03 to 0-05 mole/L, reaction time 1.5 hr at - 3 0 to - 3 5 ° C , spectra registered at - 3 0 ° C . Here and in Figs. 2 and 3 DPPH is diphenylp icrylhydrazyl. FIG. 2. EPR spectra of catalytic systems based on tribenzyltitanium and R3_,AICI,: (i-C4Hg)2AICI ( A I : T i = 2 ) (1); (i-C4Hg)~.sAICll.5 ( A l : T i = l ) (2); (i-C4Hg)t.sAlCli.s ( A l : T i = 2 ) (3); (i-C4H9)" •AICI2 (AI : T i = 2 ) (4); (C2Hs)2AICI (AI : T i = 2 ) (5); 1-4 - components reacted for about 15 hr at - 1 5 ° C ; [(CeHsCH2)3Ti]=0"02 mole/1, spectra registered at - 1 5 ° C .

Copolymerization of'butadiene With propene

t403

the case of catalysis by system I, and a large number of 1,2-butadiene units (Table 2, experiment 11). An increase in the ratio AI : Ti to 2 transforms the system to one highly selective with regard to alternating copolymerization of butadiene with propene t,Table 2, experiment 12). After (C6HsCH2)aTi has reacted with iso-C4HgAICI2 at -15°C, signals g5 and 96 practically disappear from the EPR spectra, but a number of lines appear at 1.93~ I I > I I I ) and lead to the formation of complexes characterized by EPR signals gs = 1.974 and g6 = 1.952. These systems exhibit practically identical and high selectivity; the content of dyads is 94 to 98 To. It has been shown on the example of(iso-C4Hg)l.sA1Cla.s that raising the ratio A1 :Ti from 1 to 2 leads to increased intensity of the signal 95 in the spectrum. We have also proved that when AI : Ti = 1 the reaction between components of system II is vely slow and, in contrast to the case AI : Ti=2, the signal of the starting tribenzyltitanium is preserved in the EPR spectra both at - 5 0 and -30°C. Copolymerization of butadiene with propene was studied also in the presence of systems not containing organoatuminium compounds. The system (C6HsCHz)3TiTiCI4 (IV) with the ratio Ti 4+ : Ti a+ = I, 1.5, or 2 was found to catalyse alternating copolymerization (Table 3, experiments I to 3). System IV is heterogeneous; the overall content of titanium in the precipitate (at Ti 4+ : Ti 3+ = 2) is 95 ~, the ratio CI : Ti = 3. The precipitate (finelly powdered) initiates in essence only propylene homopolymerization (Table 3, experiment 4). The signal g5 = 1.974 (Fig. 3) was found, along with other signals, in the spectrum of catalytic system IV; the overall concentration of paramagnetic centres was I ~o from the starting concentration of (C6HsCH2)3Ti. The system (C6HsCHz)4Ti-TiC14 is highly selective in catalysing alternating copolymerization of propene arid butadiene, but its activity is low (Table 3, experiment 5), and is probably due to the formation (by decomposition of (C6HsCH:)4Ti) of tribenzyltitardum which then reacts with chloroderivatives of Ti 4+ present in the system. The EPR spectrum contains a weak signal 9"5= 1.974 (Fig. 3). (CH3)3SiCHzTiCIa and C3HsTiCI3 were also tested as components of catalytic systems (Table 3, experiments 6 and 7); individually they are inactive as catalysts in copolymerization of propene with butadiene under the studied conditions. Dyads (C4H6-CaH6)n were observed in the product of copolymerization catalysed by systems containing dry gaseous hydrogen chloride: [(C!-I3)aSiCI-I2]3Ti-HCI (1:1 or

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H FXG. 3. EPR spectra of catalytic systems based on titanium derivatives: (C~HsCH2)3TiTiCI= (Ti4+ :Ti 3+ = 1) (1); (Ti4+ : Ti3 +)= 1.5 (2); [(C6HsCHz)aTi]=0.04 mole/l, - 15°C; (C6HsCH2)~Ti-TiCI4 (1 : 1) (3), -78°C; (C6HsCHz),Ti-HCI (C1: T i = 1) .(4), -15°C; [(C6HsCH~)4Ti] = 0"04 mole/l. 1 : 2) and (C6HsCH2)4Ti-HCI (1 : 1) (Table 3, experiments 8 to 10). The EPR spectrum of the latter system, containing the signal gs = 1.974, is shown in Fig. 3. The copolymer prepared under the catalytic action of the system (C6HsCH2)4Ti-HCI (1 : 2) contained 70~o of butadiene and 30 ~ of propylene u,its, the dyads (C4H6-C3H6)n were absent. On the basis of the experimental findings that (i) the selectivity of systems I, II, and III is independent of the character of the organoaluminium component (Table 3, experiments 2, 8), and (ii) the signal with gs = 1"974 is present in EPR spectra of these systems as weJl as of systems not containing organoaluminium components, and disappears upon introduction of the comonomer mixture, we are led to the hypothesis that the active centra of alternating copolymerization of propene and butene are associates of several Ra_,TiCI, compounds or of titanium compounds Ti 3+ and Ti 4÷.

Translated by M. KtmiN REFERENCES 1. N. A. VENEDIKTOVA, Ye. N. KROPACHEVA, L. V. SMIRNOVA, L. I. VYSHINSKAYA and S. Ya. TIMOSHENKO, Vysokomol. soyed. A22: 977, 1980 (Translated in Polymer Sci. U.S.S.R. 22: 5, 1077, 1980) 2. U. ZUCCHINI, E. ALBIZZATI and U. GIANINI, J. Organometal. Chem. 26: 357, 1971 3. B. A. DOLGOPLOSK, E. I. TINJAKOVA, L Sh. GUZMAN and L. L. AFINOGENOVA, J. Organometal. Chem. 244: 137, 1983 4. E. I. TINJAKOVA, L. L. AFINOGENOVA, I. Sh. GUZMAN and B. A. DOLGOPLOSK, ]nternat. Syrup. on Macromolecules, Italy, 1980 Vol. 2, p. 75 5 K.-H. THIELE and K. JACOB, Z. anorgan, aUgem. Chem. 356: 195, 1968 6. L. A. YATSENKO, A. G. BOLDYREV, I. G. ZHUCHIKHINA and Ye. N, KROPACHEVA, Kinetika i kataliz 20: 1353, 1979 7. K.-H. THIELE and W. S C H ~ E R , Z. anorgan, allgem. Chem. 379: 63, 1970 8. G.A. NESTEROV, G.A. ZAKHAROV, N.G. MAKSIMOV, V. K. DUDCHENKO, S.B. GOL'.

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SHTEIN, I. Sh. GUZMAN and Yu. I. YERMAKOV, Vysokomol. soyed. B22: 808, 1980 (Not translated in Polymer Sci. U.S.S.R.) 9. L. V. SMIRNOVA, N. A. VENED|KTOVA and Ye. N. KROPACHEVA, Vysokomol. soyed. A27: 1676, 1985 (Translated in Polymer Sci. U.S.S.R. 27: 8, 1880, 1985) 10. J. ONO and T. KEII, J. Polym. Sci. A-l, 4: 2441, 1966 11. H. HIRAI, K. HIRAKI, J. NOGUCHI, T. I_NONE and S. MAKISHIMA, J. Polym. Sci. A-l, 8: 2393, 1970

PolymerScienceU.S.S.R. Vol. 31. No. 6. pp. 1406-141I, 1989 Printed in Poland

0032-3950/89 $10.00+ .00 (~ 1990PergamonPress plc

THERMODYNAMIC PROPERTIES OF 1,4-bis-(2,2,6,6-TETRAMETHYL-4-OXY-1-OXYLPIPERIDYL)BUTADIINE AND CHARACTERISTICS OF THE POLYMERIZATION PROCESS AND OF THE RESULTING POLYMER IN THE R A N G E 0-330 K* B. V, LEBEDEV, YE. G. KIPARISOVA, YE. N. LAPSHINA, T. A. BYKOVA, YU' V. KORSHAK a n d T. V. MEDVEDEVA Chemical Research Institute at the N. I. Lobachevskii Gor'kii State University D. I. Mendeleyev Moscow Institutc of Chemical Technology (Received

23

December

1987)

By the methods of adiabatic and isothermic calorimetry, the thermodynamic properties of 1,4-bis-(2,2,6,6-tetramethyl-4-oxy-l-oxylpiperidyl)butadiine were studied, particularly the isobaric heat capacity of the monomer and polymer in the range 13.8-330 K, and their heat of combustion. The enthalpy, entropy and Gibbs energy of the polymerization process were calculated.

THE diacetylene 1,4-bis-(2,2,6,6-tetramethyl-4-oxy-I-oxylpiperidyl)butadiine (DA-1,4) is polymerized on heating, forming the dissolved polymer (PDA-1,4) [1] R /

n R--C==C--C=C - - R ---- - - [ - - C -- C = C = IC--]~.., DA-1 ~4

~here

PDA°I ~4 I{=HO

HsC ~< CH3. H3C~N ~

CH3

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O" * Vysokomol. soyed. A31" No. 6, 1283-1287,

1989.