GB2092163A - Selective Polymerization of Butadiene from C4 Fractions - Google Patents

Abstract

The invention relates to a process for selective polymerization of 1,3- butadiene by using C4-fractions which occur in the pyrolysis of petroleum, by initiating the reaction with soluble lithium initiators of the type (a) dialkali metal diamines, (b) dilithium diamides, (c) dilithium addition compounds of conjugated dienes, (d) polylithium oligodienes, (e) dilithium butane and (f) dilithium diphenol ethers. The polymerization of the butadiene is performed in the mixture without prior separation of the other components in the C4-fraction (butene-1, cis- and trans-butene-2, n- and i-butane, i-butene) and without their incorporation into the polymerizate. It has been found that butadiene can be selectively converted into polybutadienes and, if suitable anionically polymerizable monomers are added, into copolymers. The molar masses can be adjusted to suit particular applications. By the addition of suitable electrophilic end forming agents, polymer products which are functional in their end state can be obtained.

Description

SPECIFICATION Process for Selective Polymerization of Butadiene from C4 Fractions This invention relates to a process for the production of polybutadienes by means of soluble stable lithium polymerization initiators and C4 fractions, In particular the process utilizes a butadiene source consisting of unseparated olefin mixtures which occur in the pyrolysis of petroleum. The process dispenses with purification of the butadiene before the polymerization reaction and converts butadiene into a polymer product having the properties of an active polymer.

The other unsaturated and saturated hydrocarbons in the C4 fraction remain unreacted and are available for further reactions. The invention also relates to an economic process for the production of butadiene copolymers of the A-B-A type and of copolymers in which the monomers are distributed statistically: the copolymers having a certain predetermined molar mass and a narrow molecular weight distribution.

The invention also provides a means of producing, from C4 fractions containing butadienes, lowmolecular polybutadienes and butadiene copolymers which contain a functional group at the end of each chain and which have a predetermined molar mass with a narrow molecular weight distribution.

It is known that by using organolithium compounds butadiene can be polymerized selectively from C4 fractions having a butadiene content. The general interconnections found in anionic polymerization are also apparent in the case of butadiene polymerization from the C4 fraction.

According to Jap. Pat. 7342717, for instance, a C4 or C5 fraction obtained from cracking oils and containing butadiene or isoprene is treated with butyl lithium. The 100%yield of polybutadiene has similar properties to a polymer substance produced by using pure butadiene.

According to German OS 24 31 258 polybutadienes are produced by means of organolithium polymerization initiators of the general formula R-Li(R=alkyl, aryl substituent), e.g. n-butyl lithium, and a current of C4 fraction which contains butadiene and obtained in the cracking of petroleum and/or by the dehydrogenation of butane. To obtain high 1,2- structure proportions polar compounds in the form of electron donors are added to the polymerization system before or during the polymerization.

The combination of the organolithium compound with a polar compound produces, according to the said specification, a type of catalyst which reacts less with the hydrocarbons present therein as an impurity and is therefore less deactivated. This offers the advantage of requiring a smaller quantity of organolithium compound.

The examples provided in this specification nevertheless indicate that up to 65% of the organolithium compound used is still used in reacting with impurities and that only about 60% of the butadiene undergoes conversion. The use of a monolithium compound as a polymerization initiator also suffers from the drawback that polymers cannot be produced which contain a functional group at each end of the chain; the polymers obtained can only be functionalized at one end of the chain. The synthesis of block copolymers of the type A-B-A is also problematic.

It is also known that such polymers can as a rule be produced by anionic polymerization with bifunctional and mostly organo-dilithium compounds in a stoichiometrically controllable reaction, with the use of pure butadiene as the monomer (Faserforschung and Textile-technik) "Fibre Research and Textile Engineering"-25 (1974) 5, p. 191; U.S. Patent 3 135 716; German OS 2425 924; SU.

Patent 296 775).

From other publications (R. J. Sonnenfeld, Am. Chem. Soc. Polym. Chem., Polymer preprints 1 6 (1975)1, pp. 346-350) it is also known that polybutadienes and copolymers of butadiene and styrene can be produced from hydrocarbon currents having a low concentration of butadiene. In these processes it is important that actylenes and 1,2-butadienes should be removed. Only systems such as these provide polymers analogous to those obtained from very pure butadienes.

Among the known initiators are 1 ,4-diIithium butane (Japan Patent 72 29 196; Japan Patent 70 01 629; Japan Patent 70 01 628; Japan Patent 70 01 627) and the dilithium additives of conjugated dienes which contain 1 to 7 diene units (German PS 1 169 674; OS 1 170 645; DDR Patent 99 170).

Organo-alkali metal compounds of higher function, however, are generally insoluble in non-polar solvents. The addition of small quantities of monomer results in certain cases in the formation of active oligomers of which the easier solubility in hydrocarbons, while enabling further added quantities of monomer to undergo further polymerization in the homogeneous phase, nevertheless creates doubt as to whether polymerizates of defined relative molar mass can be produced.

An addition of polar solvents similarly improves the solubility of the initiators in hydrocarbons.

Many initiators cannot be produced at all except in the presence of powerful polar solvents. If polymerizations are carried out with ether-based initiator solutions of this kind the activity of the initiator and of the polymer tends to diminish as a result of ether cleavages. In known processes, therefore, the polymerization reaction is preceded by complete or partial replacement of the ether by a non-polar solvent (U.S. Patents 3 377 404, 3 388 178, German AS 1 7 68 188, German OS 18 1 7 479), since during polymerization of pure 1,3-butadiene in hydrocarbons, subsidiary reactions are unlikely, even in the presence of small quantities of polar solvents, provided the reagents are sufficiently pure.The conditions required for removal however, are often responsible for partial deactivation of the initiator and an increase in operating costs. A further drawback of the known methods is that the flash point of ether is very low, so that it cannot be used on an industrial scale without a certain risk.

It is also known to conduct polymerization of pure diolefins with alkali metal amides (U.S. Patent 2 849 432, German OS 23 55 941,24 10912, J. Polym. Sci. (1973) p. 2777, 13 (1975), p.2437, 14(1976) p. 1565).

These methods suffer from the drawback that: (i) only monomers which have been highly purified can be used for the polymerization; (ii) the alkali amide initiators are usually not easily soluble in non-poiar aliphatic hydrocarbons; and (iii) mono-functional alkali amide initiators do not enable production of polymers with a functional group at each end of the chain.

It is also known that star-shaped polymers or polymers which are functional in the final state with a functionality of greater than 2 can be produced from pure butadiene by anionic polymerization with alkali metal initiators which are tri-functional or having high functionality, such initiators generally consistingof lithium compounds (U.S. Patents 3 644 322,3 652 516,3 725 368,3 734 973, 3 862251, German OS 20 02 384,20 63 642,22 31 958,2408 696,2427 955). In these processes organo-monolithium compounds and polyvinyl aromatic compounds, such as divinyl benzene or di-isopropenyl benzene are converted into multi-metallic compounds and used as polymerization initiators.According to the particular conditions of the reaction the resulting polyfunctional organo-alkali metal compounds are branched to a greater or smaller extent or crosslinked in themselves and constitute microgels. The resulting products may also be partly or wholly of the intermolecularly cross-linked type. Microgels of this kind are insoluble and can only be used as initators for anionic polymerizations within certain limits.

An object of this invention is to enable 1.3-butadiene to be selectively polymerized from unseparated C4 fractions, which occur in particular in the pyrolysis of petroleum, by means of stable organolithium compounds which are di-functional and of higher functionality, in which process, butadiene block copolymers of the type A-B-A or butadiene copolymers with a statistical monomer distribution can be similarly provided by the addition of other anionically polymerizable monomers to the C4 fraction.

It is also intended to provide a means for synthesizing telechelic butadiene homopolymers and butadiene copolymers having a functionality of 2 and greater.

The molecular weight of the homopolymers and copolymers may be variable in any desired range, while the microstructure of the polymers may be variable with a high proportion of 1,4- or 1,2units.

The invention thus seeks to provide an economical method of producing polybutadienes, butadiene copolymers and telechelic butadiene homopolymers and/or butadiene copolymers by selective polymerization from C4 fractions and avoiding the drawbacks of the known methods.

According to this invention there is provided a process for selective polymerization of butadiene from C4 fractions to form homopolymers and copolymers having predetermind molar masses and microstructures variable in structural content from greater 1,4- to greater 1,2-, the process being carried out in the homogeneous phase, with or without non polar solvents with addition of any required polar solution medium, wherein the polymerization is initiated by a soluble di- or polyfunctional lithium initiator comprising either (a) dialkali metal diamines of the general formula::

wherein R and R' are alkyl substituents having from 1 to 30 carbon atoms, R"-Li and R"'-Li are aromatic substituents each containing one lithium atom and at least one alkyl group, and n takes the value from 1 to 12, or (b) Dilithium diamides of the general formula::

wherein R is an alkyl substituent having from 1 to 30 carbon and n takes the value from 1 to 12, or (c) dilithium addition compounds of conjugated dienes which contain from 2 to 6 monomer units to each molecule and 1 or 2 methyl groups and from 4 to 1 2 carbon atoms, to each diene molecule, said compounds being produced in a mixture of toluene, benzene or diethyi either in conjunction with tetrahydrofuran, the mixture containing from 5 to 30% by mass of tetrahydrofuran with respect to the total quantity of solvent, or (d) Polylithium oligodienes which contain from 2 to 4 lithium atoms and 2 to 10 diene units per molecule, such oligodienes being produced in non-polar solvents, or (e) dilithium butane in an asymmetric ether having a flash point above 473 K, or (f) dilithium diphanol ethers of general formula:

wherein n is from 1 to 20 and the lithium atoms occupy an ortho or para position.

Compounds such as the following are particularly suitable dilithium diamide initiators: N,N'-dilithium-N,N'-dibutyl ethylene diamide.

N,N'-dilithium-N,N'-dioctyl ethylene diamide.

N,N'-dilithium-N,N'-bisdodecyl ethylene diamide.

N,N'-dilithium-N,N'-ditetradecyl ethylene diamide.

Compounds such as the following are particularly suitable dilithium diphenol ether initiators: Bis(o-lithiophenoxy)ethane.

Bis(o-lithiophenoxy)propane.

Bis(o-lithiophenoxy)butane.

Bis(p-lithiophenoxy)butane.

Bis(o,p-lithiophenoxy)butane.

The polymerization can be carried out in a manner known per se. A polymerization can be effected in the C4 fraction without additional solvent or effectively with the butadiene concentration in the C4-fraction in solution with the additional of non-polar solvents, such as benzene, toluene, nhexane, n-heptane, cyclohexane or benzine fractions. Preference is given to the method which dispenses with the addition of any non-polar solvent as a polymerization medium, the nonpolymerizable constituents of the C4-fraction acting as diluents.

As regards the comonomers for a copolymerization process, all anionically polymerizable monomers are suitable, such as isoprene, styrene or alpha-methyl styrene, as an addition to the C4 fraction. Either block copolymers of the type A-B-A or copolymers with statistical distribution of the monomers can be produced.

The polymerization can be carried out at 1 98-4230K and preferably at 263-3730K at atmospheric pressure or increased pressure. The polymerization time is usually 1-1 0 and preferably 1-3 hours. The quantity of initiator to be employed is determined by the molar mass desired for the polymerizates, since the polymerization is stoichiometric. The invention enables homopolymers and copolymers with considerable molecular weights such as 200,000 or with a very low molecular weight such as 1,000-10,000 to be produced.

The active chain ends of the resulting polymers can be functionalized in known manner by electrophilic agents which form end groups and of which examples are CO2, alkylene oxides, epichlorhydrin or gamma-butyrolactone, so that very useful telechelic polymers can be produced.

During the polymerization reaction no discontinuity reactions occur through ether cleavage, so that after functionalization of the active polymers telechelic polymers of high functionality are obtained.

If necessary and in order to increase the 1,2-content of the polybutadiene, modifiers having this effect may be added, Examples of suitable modifiers are polar compounds such as ether, amines or alcoholates.

The products obtained by the process of this invention have the same properties as polymers obtained by using pure butadiene. The process to which the invention relates thus provides a convenient and inexpensive method of producing polybutadiene and butadiene copolymers with or without functional end groups and without recourse to an expensive butadiene extraction stage and without requiring ether solvent removal prior to the polymerization.

The process also eliminates drawbacks inherent in known methods, such as the limited solubility of the initiator in non-polar solvents, the inaccessibility of initiator systems in media of limited polarity, the difficuity of adjusting the molar mass as required and the low degree of functionality obtained in the polymer products. It is a feature of the invention that by the addition of supplementary solvation agents of varying nature and in varying quantities as modifiers the micro-structure of the polydienes in all initiator systems is variable within a large range, whereby polymers for particular applications can be produced in a planned manner.

A particular advantage of the process is the ability to produce reactive polymers having a high degree of functionality, i.e. 2 and over. These polymers can be hardened simply by means of difunctional cross-linking agents.

We have surprisingly found these effects and advantages in the polymerization of butadiene wherein the source of butadiene is a C4 fraction.

The invention will now be described in the following examples as practical embodiments, to assist clearer understand of the nature of this invention: Examples Ex. 1-6: Variable quantities of the initiator o,o'-dilithium-N,N'-dibutyl-N,N'-diphenyl-ethylene diamine dissolved in a solvent were placed in a glass autoclave together with a C4 fraction, which contains 35% by weight of 1,3-butadiene, with or without addition of a solvent. The homogeneous reaction mixtures were stirred for different periods and at different temperatures. After completion of the polymerization it was interrupted with methanol or functionalized with an alkylene oxide and hydrolysed with water.

The solvent and the remaining components of the C4-fraction were removed in a rotary evaporator at 3230K and the polymer dried in a vacuum drying cabinet at 3230K.

Polybutadienes were produced selectively. The reaction conditions and the properties of the polybutadienes are described in Tables 1 and 2.

Table 1 Reaction Conditions Reaction C4 fraction Solvent time. Temp. Donor Interruption Example Initiator in mol. ml. Type ml. h. K. Type ml. means 1 12.7 in 40 ml benzene. 90 n-heptane 520 12 355 - - M 2 30.6 in 90 ml THF. 120 THF 300 12 355 - - M 3 22.7 in 40 ml benzene. 100 n-heptane 50 12 333 - - PO 4 11.4 in 50 ml benzene. 100 - - 6 333 TEA 50 PO 5 11.4 in 50 ml benzene. 100 - - 6 333 TEA 50 EtO 6 21.3 100 - - 6 333 - - EtO M=methanol.

THF=tetrahydrofuran.

PO=propylene oxide.

EtO=ethylene oxide.

Table 2 Polymer Properties Yield Microstructure (mol-%) Ex. g. % 1,4-cis 1,4-trans 1,2. Mn. F.

1 20.5 100 34 56 10 - 2 27.3 100 - 11 89 - - 3 22.5 95 30 58 12 1400 1.84 4 22.5 100 20 46 34 2400 1.83 5 22.5 100 19 46 35 2300 1.92 6 22.5 100 36 51 13 3200 1.95 The microstructure was determined by infra-red (IR) spectroscopy and the average molar mass Mn by vapour pressure osmosis in benzol at 3030K. The functionality F was determined from the molar mass Mn and the OH content, this latter being ascertained by acidimetric titration.

Ex. 7-12: About 20-25 m mol of the initiator N,N'-dilithium-N,N'-dibutyl ethylene diamide, N,N'dilithium-N,N'-dioctyl ethylene diamide or N,N-dilithium-N,N'-ditetradecyl ethylene diamide was dissolved in 200 ml of n-heptane and placed in a glass autoclave together with 200 ml of a C4 fraction containing 35% by weight of 1,3-butadiene (corresponding to 45.6 g of butadiene). The homogeneous reaction mixture was stirred for 24 h at room temperature or for 7 h at 700 C. After the polymerization was terminated and the product worked up in a suitable manner the yield of polybutadiene produced was determined. The yield, in addition to the microstructure obtained by IR spectroscopic examination, is shown in Table 3.

Table 3 React. Microstructure, Initiator time Temp. Yield mol-% Ex. mmol. h K g. % cis. trans. 1,2.

7 N,N'-dilithium- 24 297 28.4 65 38 53 9 N,N'-dibutyl ethylene diamide.

22.65.

8 N,N'-dilithium- 7 343 44.5 100 37 55 8 N,N'-dibutyl ethylene diamide.

22.7.

9 N,N'-dilithium- 24 297 34.1 75 40 42 18 N,N'-dioctyl ethylene diamide.

21.3.

10 N,N'-dilithium- 7 343 45 100 41 47 12 N,N'-dioctyl ethylene diamide.

24.55.

11 N,N'-dilithium- 24 297 36.5 80 32 48 20 N,N'-ditetradecyl ethylene diamide.

21.4 12 N,N'-dilithium- 7 343 45 100 35 50 15 N,N'-ditetradecyl ethylene diamide.

23.8 Ex. 13 and 14 Each 48.6 mmol portion of N,N'-dilithium-N,N'-dibutyl ethylene diamide, was melted in a thinwalled glass vessel and placed in an autoclave together with 300 ml of C4 fraction. After release of this initiator the reaction mixture was stirred for 5 h at 3430K, then given an addition of 50 ml of ethylene oxide and 50 ml of propylene oxide, while cooling, and then heated up to room temperature. It is worked up as stated in Ex. 1-6.

In both experiments the polybutadiene yield was equivalent to 100%. The microstructure amounts to 47% 1 4-cis, 43% 1 4-trans and 10% 1 ,2-polybutadiene.

The polybutadiene from example 1 3 (functionalized with ethylene oxide) had an average molar mass Mn of 2080 and a functionality of 1.93. The functionality of the hydroxyl-terminated polybutadiene from example 14 was 1.89 and the average molar mass 2150.

Ex. 15-17 To the initiator oligo-isoprenyl dilithium, dissolved in a mixture of toluene and tetrahydrofuran (volumetric ratio 90:10) a C4 fraction containing 35 and 37.5% by weight of 1 ,3-butadiene was continuously added at 2830K in a glass autoclave over a period of 2 h. After completion of the polymerization the process was interrupted with methanol, ethylene oxide and gamma-butyrolactone (BLT), hydrolysis then being carried out with water. The reaction conditions are shown in Table 4 and the yields and properties of the polymer in Table 5.

Table 4 Initiator, C4 fraction.

mmol in ml. % weight Solvent Interruption Ex. solvent mixture. ml. butadiene Type. ml. medium.

1 5 12.5 in 90 35 n-heptane. 520 M.

18 ml.

16 75 in 320 37.5 - - EtO 110 ml.

17 30 in 320 37.5 - - BLT 45 ml.

Table 5 Yield Microstructure Mn Ex. g % mol-% 1,4. mol-% 1,2. calc. determined F 15 20.5 100 21 79 1650 1670 16 73 98 20 80 1000 1050 1.86 17 75 100 25 75 2500 2350 2.0 Ex. 18-20.

Ex. 18.

To 50 mmol of oligo-isoprenyl-trilithium, dissolved in 100 ml of n-heptane and 26 ml of triethylamine, 200 g of a C4 fraction, containing 37.5% by weight of butadiene, was added continuously at 350C in a glass autoclave over a period of 2 h.

After completion of the polymerization, 13.5 g of ethylene oxide was added to the homogeneous solution, which was then hydrolysed with water This provided 74 g of a liquid polybutadiene containing a primary OH group at each end of the chain.

The åverage molar mass amounted tb 1 580 and corresponded to the molar mass of 1500 calculated. The polymer had a microstructure of 64.5% of 1,4 and 35.5% of 1,2 structure. The functionality determined by acidimetric titration amounted to 2.53. The butadiene was 100% converted.

Ex. 19.

200 g of C4 fraction containing 37.5% by weight of butadiene was added to a solution of 37.5 mmol of oligoisoprenyl trilithium in 73 ml of n-heptane and 1 9.5 ml of triethylamine. The homogeneous reaction mixture was stirred in an autoclave for 3 h at 350C and then given an addition of gamma-butyrolactone while cooling.

The polymer yield was equivalent to 100%. The relative average molar mass determined osmometrically amounted to 2140, while that determined by calculation amounts to 2000. The product had a hydroxyl content of 2.0%, resulting in a functionality of 2.51.

Ex. 20 28.1 mmol of oligo-butadienyl tetrelithium in 60 ml of n-heptane and 27 ml of tetramethyl ethylene diamine and 200 g of a C4 fraction containing 37.5% of butadiene was stirred for 2 h at 200C and then functionalized with twice the molar quantity of ethylene oxide. After hydrolysis had been carried out and the polymer worked up in a rotary vacuum evaporator a 100% yield of a polybutadiene was obtained which had an OH content of 2.09%, a molar mass of 2000 and microstructure of 70% and 1,2 and 30% of 1,4 configuration. The functionality amounted to 3.64.

Ex. 21 and 22.

1 5 ml of a solution of 12.5 mmol of dilithium butane in methyl isopropyl ether was placed with 520 ml of toluene in a glass autoclave together with 90 ml of a C4 fraction containing 22 g of butadiene. The homogeneous reaction mixture was stirred for 2 h at 400C and the polymerization then interrupted with methanol. The yield amounted to 20 g of polybutadiene, corresponding to an almost 1 00% conversion of the butadiene.

Ex. 22.

66.6 g of a C4 fraction containing 37.5% by weight of butadiene was continuously added, at 400 C, in a glass autoclave, to 25 mmol of dilithium butane in 30 ml of methyl isopropyl ether, over a period of 2 h. After the completion of the polymerization 4.5 g of ethylene oxide was added and hydrolysis then carried out with water.

This provided 24 g of liquid polybutadiene which contained a primary OH group at each end of the chain. The average molar mass amounted to 1070 and corresponds to the molar mass of 1000 calculated from the ratio between monomer and initiator. The polymer had a microstructure of 61% of 1,4 and 39% of 1,2 structure. The functionality, determined by acidimetric titration, amounted to 1.92.

The butadiene was almost 100% converted.

Ex. 23-26.

About 35 to 50 mmol of the initiator bis (o-lithiophenoxy)-ethane and bis (o,p-lithiophenoxy) butane were dissolved in 200 ml of tetrahydrofuran and placed in a glass autoclave, for reaction, with a C4 fraction containing 37.5% of 1 3-butadiene (corresponding to 50 g of butadiene). The homogeneous mixture was stirred for 3 h at 283-31 30K. After the polymerization was completed and the product suitably worked up, the polybutadiene yield was determined. Table 6 illustrates the yield and the microstructure obtained by IR spectroscopy.

Table 6 React.

Initiator, Time. Temp. Yield. Micro-structure.

Ex. mmol. h. K g % Mn 1,4-cis 1,4-trans 1,2 23 Bis(o-iithio- 3 308 45 90 5100 - 21 79 phenoxy)ethane.

38.0.

24 Bis(o-lithio- 3 284 46.5 93 3740 9 13 78 phenoxy)butane.

51.2.

25 Bis(p-lithio- 3 313 44.8 89.6 3130 - 16 84 phenoxy)butane.

37.2.

26 Bis(o,p-lithio- 3 308 46 92 3320 - 19 81 phenoxy)butane.

41.2.

Ex. 27.

38.2 mmol of the initiator bis(p-lithiophenoxy)butane was placed in a glass autoclave, 200 ml of the aforementioned C4 fraction being added thereto by condensation. After 5 hours the polymerization carried out at 3330K is interrupted. The polybutadiene yield amounted to 95% of the theoretical yield.

The following microstructure of the polymer was obtained: 45% 1,2; 35% 1 ,4trans and 20% 1,4-cis polybutadiene.

Ex. 28.

7.4 mmol of the initiator bis(p-lithiophenoxy) butane was dissolved in 100 ml of THF reacted in a glass autoclave with a C4 fraction having the aforementioned composition. The homogeneous mixture was stirred for 3 h at 2840K. A surplus of 2-10 mol of butyrolactone per equivalent lithium was then added, while cooling to 2430K. The product was heated to room tempersture and the polymer suitably worked up. The product had a functionality, F, of 1.75. The molar mass, determined by the vapour pressure osmometric method, amounted to 6300, the figure obtained by calculation being 1550. The microstructure for this polymer amounted to 17% 1 ,4-trans and 83% 1 units.

Ex. 29.

Ex. 28 is repeated but the polybutadiene functionalized by means of benzaldehyde instead of butyrolactone. The resulting polymer had almost exactly the same microstructure. The functionality determined was F=1 .68, the average relative molar mass determined by the vapour pressure osmometric method being 3620.

Ex. 30.

Analogously to Ex. 27, selective polymerization from the C4 fraction was performed by means of bis(p-lithio-phenoxy) butane and without the addition of solvent. Butyrolactone was subsequently added while cooling. The polybutadiene yield amounted to 93% of the theoretical yield. Having the same microstructure as in Ex. 27 the polymer was found to have a functionality, F, of 1.65, the average relative molar mass being 6900.

Ex. 31.

A mixture of 35 ml of butadiene, contained in 100 ml of a C4 fraction and 1 5 g of styrene, in 300 ml of n-heptane, was added to a benzene solution of 26 mmol of the initiator O,O'-dilithium-N,N'dibutyl-N,N'-diphenyl ethylene diamine. The homogeneous reaction mixture was stirred in an autoclave for 12 h at 3430K. This provided a copolymer of butadiene and styrene, with a yield of almost 100%.

The product had a styrene content of 40% and a polybutadiene structure of 90% 1,4- and 10% 1,2units.

Ex. 32.

A mixture of 45.6 g of butadiene, contained in 200 ml of a C4 fraction, and 4.5 g of styrene, in 200 ml of heptane, was added to 200 ml of a heptane solution of 33.2 mmol of the initiator N,N'dilithium-N,N'-dibutyl ethylene diamide. The reaction mixture was stirred in an autoclave for 10 h at 3430K. This provided a copolymer of butadiene and styrene with a yield of 100%. The product had a styrene content of 10%.

Ex. 33.

A mixture of 100 ml of a C4 fraction containing 35% by weight of butadiene, 1 5 g of styrene, in 300 ml of toluene, was added to a solution of 26 mmol of oligobutadienyl dilithium in 40 ml of toluene tetrahydrofurane mixture. The homogenous reaction mixture was stirred in an autoclave for 2 h at 2930K. This provided a copolymer of butadiene and styrene with a yield of 100%. The styrene content of the product amounted to 40%.

Ex. 34.

A mixture of 70 ml of butadiene, contained in 200 ml of C4 fraction, and 30 g of styrene, in 300 ml of toluene, was added to a solution of 50 mmol of lithium butane in 60 ml of methyl isopropyl ether. The homogeneous reaction mixture was stirred in an autoclave for 2 h at 31 30K. This provided a copolymer of butadiene and styrene with a yield of 100%. The styrene content of the product amounted to 38%.

Claims (23)

Claims

1. A process for selective polymerization of butadiene from C4-fractions to form homopolymers and copolymers having predetermined molar masses and microstructures variable in structural content from greater 1,4- to greater 1,2-, the process being carried out in the homogeous phase, with or without non polar solvents with addition of any required polar solution medium, wherein the polymerization is initiated by a soluble di- or polyfunctional lithium initiator comprising either.

(a) dialkalki metal diamines of the general formula:

wherein R and R' are alkyl substituted having from 1 to 30 carbon atoms, F"-Li and R",-Li are aromatic substituents each containing one lithium atom and at least one alkyl group, and n takes the value from 1 to 12, or (b) Dilithium diamides of the general formula::

wherein R is an alkyl substituent having from 1 to 30 carbon and n takes the value from 1 to 12 or (c) lithium addition compounds of conjugated dienes which contain from 2 to 6 monomer units to each molecule and 1 or 2 methyl groups and from 4 to 12 carbon atoms to each diene molecule, said compounds being produced in a mixture of toluene, benzene or diethyl either in conjunction with tetrahydrofuran, the mixture with respect to the total quantity of solvent, or (d) Polylithium oligodienes which contain from 2 to 4 lithium atoms and 2 to 10 diene units per tetrahydrofuran, the mixture containing from 5 to 30% by mass of tetrahydrofuran with respect to the total quantity of solvent, or (e) dilithium butane in an asymmetric ether having a flash point above 473K, or (f) dilithium diphanol ethers of general formula::

wherein n is from 1 to 20 and the lithium atoms occupy an ortho or para position.

2. Process according to Claim 1, wherein homopolymers and copolymers are produced with functional groups.

3. Process according to either preceding claim wherein the predetermined molar masses lie in the range from 1000 to several hundred thousand.

4. Process according to any preceding claim wherein the dialkali metal diamines are dilithium ditertiary diamines.

5. Process according to any preceding claim wherein the dialkali metal diamine alkyl substituents contain from 3 to 1 5 carbon atoms.

6. Process according to any preceding claim wherein the aromatic substituents of the dialkali metal diamines are phenyl groups wherein the lithium atom occupies an ortho position.

7. Process according to any preceding claim wherein the value of n in the dialkali metal diamines is 2 or 3.

8. Process according to any preceding claim wherein the dilithium diamide alkyl substituent contains from 3 to 20 carbon atoms.

9. Process according to any preceding claim wherein the value of n in the lithium diamide is from 2 to 6.

10. Process according to any preceding claim wherein the dilithium addition compounds of conjugated dienes are produced from 1,3-butadiene, isoprene or 2,3-dimethyl-1 3-butadiene.

11. Process according to any preceding claim in which the polylithium oligodienes contain from 2 to 6 diene units per molecule.

12. Process according to any preceding claim wherein the asymmetric ether is methyl isopropyl ether or methyl tertiary-butyl ether.

13. Process according to any preceding claim wherein the value of n is from 2 to 6 in the dilithium diphenol ether.

14. Process according to any preceding claim wherein the dilithium diphenol ether is selected from the group comprising bis(o-lithiophenoxy) ethane, bis(o-lithlophenoxy) propane, bis(olithiophenoxy) butane, bis(p-lithiophenoxy) butane, bis(o,p-lithiophenoxy) butane.

1 5. Process according to any preceding claim wherein the polymerization is performed in the C4fraction without additional solvent.

1 6. Process according to any preceding claim wherein the polymerization is performed at temperatures and pressures which ensure that the monomer mixture will be in the liquid phase.

17. Process according to Claim 16, wherein the temperature range is from 263 to 373 K.

18. Process according to any preceding claim wherein any anionically polymerizable monomers are used as comonomers for production of butadlene copolymers.

1 9. Process according to Claim 1 8 wherein the anionically polymerizable monomer is selected from acrylonitrile, styrene, alpha-methylstyrene, isoprene and methyl methacrylate.

20. Process according to any preceding claim wherein electrophilic end- group forming agents are used in the production of telechelic polymers.

21. Process according to Claim 20 wherein the electrophilic end group forming agents are selected from CO2, alkylene oxides, epichlorhydrin and lactones.

22. A process for the selective polymerization of butadiene from C4-fractions to form butadiene polymers substantially as herein described and as exemplified in any of examples 1 to 34.

23. A polymer product produced by the process of any preceding claim.