DD236321A1 - PROCESS FOR SELECTIVE BUTADIAL POLYMERIZATION FROM C LOW 4 FRACTION - Google Patents

Abstract

The invention relates to a process for the polymerization of 1,3-butadiene using the C4 fraction obtained in the petroleum pyrolysis by means of stable, by reaction of Monolithiumorganylen, R-Li (alkyl, cycloalkyl, aryl, Ar-alkyl radical) , with tetraallylalkylenediamines, (CH 2 CH-CH 2) 2 N (CH 2) n N (CH 2 -CHCH 2) 2 (n 2 -6) initiator solutions obtained in the molar ratios 2: 1 to 5: 1 in aliphatic, cycloaliphatic, olefinic or aromatic hydrocarbons as dismutating agents, wherein the polymerization of butadiene from the mixture without prior separation of the other components of the C4 sections (butane (1), cis and trans-butene (2), n- and i-butane, etc.) and without their incorporation into the Polymer is carried out. It has been found that butadiene can be converted selectively into polybutadienes and, with addition of suitable anionically polymerizable monomers, into copolymers and their molecular weights can be adjusted in a targeted manner. By adding suitable agents, multifunctional polymers with functionality of 2 to 4 and above can be prepared.

Description

= H ¹ = R ¹¹ = R ¹¹¹ = GH ^ "-CE

"GH Li

GH R = R ^f = R ¹ '= GH ^^''^ CH - and R ¹ · * = H ⁿ "-CH ₂ -

Li GH (Li) - OH ₂ - (R ^lfft = iso-albyl, n-ulbyl, cyclic allyl,

GH aryl, arylalkyl) j R = R ¹ = GH ₂ * "" ^ GH - and

Li R '"= R" ♦ · = R "". -GH ₂ -GH (Li) -GH ₂ j

R = allyl and R ¹ = R "= R" * = VZ ^ " " ^ GH - or

, Li R "" - GH ₂ - GH (Li) - GH ₂ - j R = R '= allyl and

GH 2 ^м = R ^ff '= GHJ ^ "^ GH - or R ¹ · = ^

Li Li

and R ¹ '· = R ¹ ' · ^f - GH ₂ - GH (Li) - GH ₂ -

2. The method according to item 1, characterized in that the polymerization in the C ₄ fraction can be carried out without additional solvent.

3. The method according to item 1 and 2, characterized in that the polymerization is carried out at such temperatures and pressures that the monomer mixture is in the liquid phase.

4. The method according to item 1 to 3, characterized in that the polymerization in the temperature range of 263 to 353 K is performed.

5. The method according to item 1 to 4, characterized in that for the preparation of block copolymers or of random copolymers all anionically polymerizable monomers, such as. For example, isoprene, styrene, alpha-methylstyrene, be used as comonomers.

6. The method according to item 1 to 5, characterized in that for the preparation of terminal functional, low molecular weight polymers having functionalities between 2 and 4 and above electrophilic, end-group forming agents such. As CO ₂ , alkylene oxides, epichlorohydrin, gamma-butyrolactone, are used.

Field of application of the invention

The invention relates to an economical process for preparing polybutadienes by means of soluble stable lithium polymerization initiators using C ₄ fractions, especially of crude olefin mixtures obtained as a butadiene source in petroleum pyrolysis, the separation of the butadiene being saved before the polymerization reaction and butadiene being converted into a polymer product alone which has the properties of a living polymer.

The unsaturated and saturated hydrocarbons still present in the C ₄ fractions used remain unreacted and are available for further reactions.

Furthermore, the invention relates to an economical process for the preparation of type A-B-A butadiene polymers and random monomer distribution copolymers, the copolymers having a predetermined molecular weight and narrow molecular weight distribution.

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The invention also enables the production of low molecular weight polybutadienes and butadiene copolymers containing a functional group at each chain end and having a predetermined molecular weight with a narrow molecular weight distribution, using butadiene-containing C ₄ fractions

 The microstructure of the polymers can be adjusted with a high proportion of 1,4 or 1,2 units.

Characteristic of the known technical solutions

It is known that butadiene can be polymerized selectively by means of organolithium compounds from butadiene-containing C ₄ fractions. The general relationships found in anionic polymerization can also be deduced from butadiene polymerisation. Recognize C ₄ fraction. So z. For example, according to Japanese Pat. No. 7,342,717, a C ₄ or C ₅ fraction containing butadiene or isoprene is treated with butyl lithium. The polybutadiene obtained in 100% yield has similar properties as a polymer prepared using pure butadiene. According to DE-OS 2,431,258 polybutadienes are prepared by solution polymerization by means of organolithium polymerization initiators of the general formula R-Li (R = alkyl, aryl), z. For example, n-butyllithium, using a butadiene-containing C ₄ stream, which is obtained in the cracking of petroleum and / or by dehydrogenation of a butane feed. The formation of high 1,2-structuralities is achieved by adding polar compounds as electron donors to the polymerization system before or during the polymerization. The combination of the lithium organo compound with a polar compound gives, according to this DE-OS, a catalyst species which reacts less with the ε-hydrocarbons present as an impurity and consequently is deactivated to a lesser extent than would otherwise be the case. This has the advantage that a smaller amount of lithium organo compound must be used.

However, it can be seen from the examples of the above DE-OS that up to 65% of the lithium organo compound used is needed to trap impurities and that the butadiene conversion is only about 60%. The use of a monolithium compound also has the disadvantage that no polymers can be prepared which contain a functional group at each end of the chain; the resulting polymers are in principle functionalizable only at one end of the chain. Furthermore, the synthesis of block copolymers of the type A-B-A is problematic. The skilled worker is aware that such polymers are generally by anionic polymerization with bifunctional, usually dilithium in stoichiometrically controllable reaction using pure butadiene and z. B. Styren can be represented as monomers (Faserforschung and Textiltechnik 25 (1974) 5, p 191, US Patent 3,135,716, DE-OS 2 425 924, SU-PS 296 775).

From other work (RJ Sonnenfeld, Am.Chem.Soc Polym. Chem., Polymer preprints 16 [1975] 1, pp 346-350) is also known that polybutadiene and butadiene-styrene copolymers are prepared from hydrocarbon streams low butadiene concentration can. It is important. Acetylenes and 1,2-butadienes to remove. Only such systems yield polymers analogous to those obtained from pure butadiene.

Common initiators are the 1,4-dilithium butane (JA-PS 7 001 629, JA-PS 7 001 628, JA-PS 7 001 627) and the dilithium adducts of conjugated dienes containing 1 to 7 diene units (DE-PS 1 169 674; DE-AS 1 170 645). However, higher functionality alkali organo compounds are generally insoluble in nonpolar solvents. The addition of small amounts of monomer leads in some cases to the formation of living oligomers whose better solubility in hydrocarbons, although the further polymerization of newly added amounts of monomer in the homogeneous phase allows, but the representation of polymers of defined relative molecular weight appears problematic.

An addition of polar solvents also improves the solubility of the initiators in hydrocarbons. Many initiators can only be prepared in the presence of strongly polar solvents. If polymerizations are carried out with such ether-containing initiator solutions, it is very easy to reduce the initiator efficiency as a result of ether cleavage. Known processes therefore provide complete or partial replacement of the ether by a non-polar solvent prior to the polymerization reaction (US Pat. Nos. 3,377,404, 3,388,171, DE-AS 1 768 188, DE-OS 1 817 479), since in the polymerization of pure 1,3-butadiene in hydrocarbons even in the presence of small amounts of polar solvents with appropriate purity of the reactants side reactions are unlikely. However, the conditions required to remove the ether often already result in partial deactivation of the initiator and increased operating costs. Another disadvantage of the known method is that the self-ignition point of the diethyl ether is very low, so that it can not be used without risk on an industrial scale.

It is also known that from pure butadiene by anionic polymerization with tri- or higher functional alkoxide, usually lithium compounds, star-shaped polymers or terminally functional polymers having a functionality greater than 2 can be represented (US Patent No. 3,644,322, 3,652,516, 3rd 725 368, 3 734 973, 3 862 251, DE-OS 2 003 384, 2 063 642, 2 231 958, US Pat. Nos. 2,408,696, 2 427 955).

According to these methods, organomonolithium compounds are reacted with polyvinylaromatic compounds such as divinylbenzene or diisopropenylbenzene to give multi-metalated compounds and used as polymerization initiators. Depending on the reaction conditions, the resulting polyfunctional organoalkali metal compounds are more or less strongly branched or crosslinked and constitute microgels. Partially or completely intermolecularly crosslinked products can also be formed. Such macrogels are insoluble and only partially usable as initiators for anionic polymerization.

Object of the invention

The aim of the invention is to selectively polymerize 1,3-butadiene from undissolved C ₄ fractions, which are obtained in particular in petroleum pyrolysis, by means of a stable multifunctional lithium initiator, by addition of other anionically polymerizable monomers to the C ₄ fraction and butadiene block copolymers of the type ABA or butadiene copolymers are to arise with statistical monomer distribution.

Furthermore, the synthesis of telechelic Butadienhomo- and butadiene copolymers, which have a functionality of 2 and higher, should be possible.

The molecular weight of the homo- and copolymers should be adjustable in any desired range, the microstructure of the polymers with a high proportion of 1,4 or 1,2 units.

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Explanation of the essence of the invention

The invention has for its object to develop an economical and efficient process for the preparation of polybutadienes, butadiene copolymers, telechelic Butadienhomo- or butadiene by selective polymerization of C ₄ fractions, the disadvantages of the known methods are eliminated and the above requirements are met. The object is achieved in that hydrocarbon-soluble polyfunctional lithium initiators, such as Multilithiumditertiärdiamine type RR'N (CH ₂ ) "NR" R '"are used, wherein the radicals R symbolize the following groups:

= R ¹ = R ¹¹ = R ¹ "= GEf '

-OH - and a ^MI = H ^tMI -CEU-

R = R ¹ = R ¹ '= C

Id CH (Li) - CH ₂ - (R * ¹ "= iso-alkyl, n-alkyl, cyclic alkyl,

CHaryl, arylalkyl) j R = R ¹ = CH 1 - ^^^^ CH - and

Ы S "= E '" = E "" - CH ₂ - CH (Li) - CH ₂ j

CH R = allyl and R ¹ = R ^{1 f} = R '"= CH ₂ ' ^ * '- CH - or

Li

R "'- - CH ₂ - CH (Li) - CH ₂ - j R = R' = allyl and

CH CH

R »» = R · «'= CH"-' · CH - or R ^{1 f} = GET

Li and R ^f "= R ¹¹¹ * - CH ₂ --CH (Li) -

The polymerization is carried out in a known manner with the addition of C ₄ fraction to the initiator solution at temperatures between 263 and 353 K, usually between 303 and 333 K. The result is gel-free, a low vinyl group content containing living homopolymers by addition of vinyl-bearing organic compounds, such as As styrene, alpha-methyl styrene, acrylonitrile and similar substances, in living block copolymers of the type B (-A) _n (n = 2, 3, 4) or random copolymers can be converted. The homopolymers may be liquid to solid depending on the molar ratio of initiator monomer used; the average molecular weights of the polymers are adjustable and can reach values between 500 and more than 100,000 g / mol. When using the tetrafunctional initiator, the calculated and osmometrically found molecular weights and the calculated and found functionalities of the liquid polymers match very well. When using the bifunctional and trifunctional initiator for the polymerization most likely chain building processes take place involving free allyl groups of the initiator, whereby the values of the found molar masses or functionalities of the polymers are greater than the calculated.

By adding water or alcohol, the Li-C bonds are solvolyzed and unfunctionalized polymers are obtained.

Treating the living polymers with ethylene oxide, butyrolactone, carbon dioxide and similar compounds results in polymers bearing functional groups (-OH, -COOH and the like) at the chain ends.

These functionalized polymers can be reacted with appropriate polyfunctional reagents such as isocyanates, epoxies, etc.

autocatalytically, d. H. without the addition of other crosslinking-catalyzing compounds, are converted into polymers having a dense network.

Polymerization of the butadiene in the liquid C ₄ fraction is possible without the addition of nonpolar solvents, with the remaining components of the C ₄ fraction acting as a diluent.

The microstructure of the polymers is adjustable within wide limits. If the polymerization is carried out in non-polar solvents, then butadiene polymers having over 70% 1,4-structure content are obtained.

If, prior to the polymerization, polar solvents (tetramethylethylenediamine, tetrahydrofuran or similar substances) are added, polymers having a very high 1,2-structural proportion are formed.

The products produced by the process according to the invention have the same properties as the polymers obtained using pure butadiene. The process of the present invention thus provides a convenient method for preparing polybutadienes and butadiene copolymers with and without functional end groups without the need for an expensive butadiene extraction step.

The examples given are intended to illustrate the process according to the invention.

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embodiments example 1

35 mmol of the initiator RR'N (CH ₂ ) ₂ NR "R '" (I) (R = CH ₂ = CH-CH ₂ -;

R «= R · '= OHg ^" ^ CH-JR ^{1 f} ' = 2 "" -GH ₂ -GH (Li) -CH ₂ -

(R "= ISO-C ₄ H ₉ ), dissolved in 200 ml of benzene, 313 K are reacted with 980 mmol of 1,3-butadiene contained in 220 ml of C ₄ fraction. The polymerization is complete after 150 minutes and the butadiene-free C ₄ fraction is distilled off. The polymer is isolated by precipitation in methanol. The result is a thin liquid product with an osmometrically determined molecular weight of M _n = 2700 (calculated ¹ >: 1512). The microstructure has 47% 1,4-trans, 1,4-cis and 27% 1,2-PB fractions. The yield of polymer is 95% d. Th.

Example 2

To 12.5 mmol of the initiator RR'N (CH ₂ ) ₂ NR "R '" (II)

..CH

(H = R * = R * * = CH ₂ '''''' ^ CE-; R * ^ = XSO-C ₄ H ₉ -CH ₂ -CH (Li) -OH ₂ -),

Li

dissolved in 200 ml of benzene are added at 313 K 1.96 mol of 1,3-butadiene contained in 440 ml of C ₄ fraction. The mixture is then polymerized for 150 min. The butadiene-free C ₄ fraction is distilled off, the reaction terminated by precipitation in methanol. The result is a viscous product with the average molecular weight M _n = 9620 (calculated ¹¹ : 8467) and a microstructure of 48% 1,4-trans, 26% 1,4-cis- and 26% 1,2-PB- shares. The yield is 100%.

Example 3

To 50 mmol of the initiator II in 350 ml of benzene are added at 313 K 1.96 mol of butadiene (1.3), contained in 440 ml of C ₄ fraction, with the solution being homogenized. Now it will be 150 min. polymerized and the butadiene-free C ₄ fraction is distilled off thereafter, then quenched with methanol. The result is a liquid polymer of average molecular weight M _n = 2520 (calc. ' ¹ 2117) and a microstructure of 48% 1,4-trans, 28% 1,4-cis and 24% 1,2-PB shares , The yield of polymer is 95% d. Th.

Example 4

To 50 mmol of the initiator RR'N (CH ₂ ) ₂ NR "R '" (III)

(R = R 1 = CH ₂ = OH-OH ₂ -,

CH ₂ -CH (Li) -CH ₂ -) in 250 ml of benzene are condensed at 313 K 980 mmol of 1,3-butadiene, contained in 220 ml of C ₄ fraction. After 150 min of polymerization is added to 268 Kab cooled and 220 mmol of ethylene oxide. The solution solidifies to a white, firm gel. It is further stirred and then, after distilling off the butadiene-free C ₄ fraction hydrolyzed with water. By centrifuging, water and lithium salts are separated from the benzene solution. This is concentrated on a vacuum rotary evaporator and dried. The result is a liquid polymer of average molecular weight M _n = 3700 (calc. ' ¹ 1 058). The functionality was determined to be F = 2.9. The polymer has the same microstructure as that listed in Example 1. The yield is 95% d. Th.

Example 5

To 2.5 mmol of the initiator II, dissolved in 200 ml of benzene, 35 g of 1,3-butadiene, contained in 145 ml of C ₄ fraction, and 15 g of styrene are added at 323 K with stirring. The homogeneous solution is stirred for 300 min, the butadiene-free C ₄ fraction is distilled off and then precipitated in methanol. The result is a random copolymer with 33% styrene content and a PB microstructure of 74% 1,4- and 26% 1,2-shares.

Example б

To 2.5 mmol of the initiator II in 300 ml of benzene at 328 K 35 g of butadiene (1.3), contained in 145 ml of C ₄ fraction added and polymerized for 300 min. Thereafter, 15 g of styrene are metered in and polymerized for a further 300 min. Subsequently, the butadiene-free C ₄ fraction is distilled off. From the polymer solution 49 g of a star-shaped block copolymer with a styrene content of 33% and a PB microstructure of 72% 1,4- and 28% 1,2-units were isolated.

¹¹ without consideration of the initiator molecule incorporated into the polymer chains and (in the case of functionalized polymers) without taking into account the further increase in molecular weight which has occurred due to the functionalization.

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Example 7

200 ml of THF are added with cooling to 50 mmol of the initiator III in 120 ml of benzene. To this is added 980 mmol of butadiene (1.3) contained in 220 ml of C ₄ fraction. Now is polymerized for 180 min at 263 K. The butadiene-free C ₄ fraction is distilled off and the reaction stopped by precipitation in methanol. The result is a polymer of average molecular weight M _n = 3100 (calculated ¹¹ 1058) and a microstructure of 87% 1,2- and 13% 1,4-trans proportions. The yield is 95% d. Th.

Example 8

To 35 mmol of the initiator I in 250 ml of benzene are added at 313 K980 mmol of butadiene (1.3), contained in 220 ml of C ₄ fraction. After a polymerization time of 150 minutes, the mixture is cooled to 268 K and 220 mmol of gamma-butyrolactone are added. This results in a rotorange solid gel, which is worked up after distilling off the butadiene-free C ₄ fraction analogous to Example 4. A low-viscosity polymer having an average molecular weight M _n = 3040 (calculated as ¹ : 1512) and the functionality F = 3.5 is obtained. The yield of polymer is 95% d. Th.

Example 9

To 25 mmol of the initiator II in 175 ml of benzene are added at 313 K980 mmol of butadiene (1.3), contained in 220 ml of C ₄ fraction. After a polymerization time of 150 minutes, the mixture is cooled to 268 K and 220 mmol of ethylene oxide are added. The result is a solid white gel, which is worked up analogously to Example 4. This gives a low-viscosity polymer of average molecular weight M _n = 2500 (calculated ¹ ': 2117) and the functionality F = 3.8. The yield is 95% d. Th.

Example 10

To 35 mmol of the initiator I, after removal of the solvent benzene in vacuo 220 ml of C ₄ fraction containing 980 mmol of butadiene (1.3) was added. It is polymerized for 240 min at about 313 K and then distilled off the butadiene-free C ₄ fraction. The viscous "living polymer" is hydrolyzed with water to give a liquid product of average molecular weight M _n = 2980 (calculated ¹¹ : 1512) and a microstructure of 70% 1,4- and 30% 1,2-shares Yield is 96% of theory.

Claims (1)

-ι- 350 Invention claim: 1. A process for the selective butadiene polymerization of C ₄ fractions to homopolymers and / or copolymers with or without functional end groups and with predetermined molecular weights in the homogeneous phase in the presence of lithium initiators, characterized in that as initiators HC solutions of Multilithiumditertiärdiaminen the type RR ' N (CH ₂ ) _n NR "R '" are used, where the radicals R symbolize the following groups: