CS240556B1 - 1,3-butadiene selective polymerization method from c4 fractions - Google Patents

Abstract

Method of Selective Polymerization of Butadiene- -1.3 from Ci fractions using organoalkalokic initiators in the presence of a tetralithium suspension initiators obtained by o-, m, or p-vinylbenzene with a hydrocarbon solution dilithium compounds, in particular of the compound dilithla to bdd-1,3 or isoprene.

Description

240556 3

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for selectively measuring butadiene-1,3 from Ci fractions using orthanoalkalko initiators, in particular lithium initiators, to live low molecular weight polymers followed by functionalization of living polymers with electrophilic agents, especially alkylene oxides, oxidic or gamma-butyrolactone. It is known from German Offenlegungsschrift No. 24 31 258 that sepolybutadienes can be prepared by solution polymerization using organolithium polymerization initiators of the general formula R-Li, wherein R is alkyl or aryl, for example n-butyllithium, using a C4 fraction containing butadiene which it is produced by cracking oil or by dehydrogenating the butane fraction. However, the efficiency of the initiator is low, as the examples in the application show that up to 65% of the organolithium compound used to capture impurities and convertebutadiene is only about 60%. A disadvantage of using a monolithium compound as a polymerization initiator is also that polymers with more than one functional end group in the molecule cannot be prepared. The synthesis of star-shaped polybutadienes is possible only by condensation of monofunctional living polymers with polyfunctional condensing agents, which reaction is generally not selective and the resulting polymers do not have reactive groups at the chain ends.

NDR Patents 154,980, 154,981 and 154,982 describe a process for the selective polymerization of butadiene from Ct fractions with bifunctional alkaloorganic initiators with 100% polybutadiene yielding bifunctional polybutadienes; However, polybutadienes with a functionality greater than 2 and star-shaped polymers cannot be obtained.

It is also known to produce star-shaped polymers or polymers with a functionality greater than 2 by anionic polymerization in the presence of tri- and more functional alkalooranocane initiators, mostly lithium compounds, with the aid of anionic polymerization. 3,644,322, 3,652,516, 3,725,368, 3,734,973, 3,862,251, NSR-DOS 20 63 642, 22 31 958, 24 08 696 and 24 27 955).

According to these methods, the organomolithium compounds are reacted with polyvinyl aromatic compounds such as divinyl benzene or diisopropylbenzene to form di- and multi-methylated compounds further useful as initiators. According to the reaction conditions, the polyfunctional alkalooranocyanate compounds obtained are more or less strongly branched, or crosslinked to form microgels. They may also be formed from parts or intermolecularly crosslinked products which are only of limited use as initiators of anionic polymerization. Multiple-methylated initiators have a high molecular weight relative to themselves, making them unsuitable for the synthesis of lower molecular weight telechelic polybutadienes. '4

These disadvantages are eliminated by the method of selective polymerization of butadiene-1,3 from Cr fractions by means of organoalkalokic initiators, in particular lithium initiators to live polymers of low to medium molecular weight, followed by functionalization of living polymers by electrophilic agents, in particular, alkylene oxides, carbon dioxide or gamma-bu-tyrolactone according to the invention, which consists in carrying out the polymerization in a C4 fraction in the presence of a suspension of tetralithium initiators prepared by the reaction of o-, m- or p-divinylbenzene or mixtures thereof with a hydrocarbon solution of a dilithium compound, in particular a dilithium to butadiene-1,3 orisoprene adduct containing 1 to 7 pulp units or dilithium butane, in a molar ratio of divinylbenzene to dilithium compound 1: 2 in a hydrocarbon solvent, in particular benzene or toluene, optionally in mixtures of hydrocarbons with ether, in particular diethyl ether, methylterbutylether m or terahydrofuran, at a temperature of 198 to 423 K. Polymerization can be carried out at a temperature of 263 to 373 K.

These initiators are insoluble in the reaction medium and are used as suspensions in the appropriate solvent. They are linear, non-crosslinked, low molecular weight organophilic compounds with an average molecular weight of less than 500. Therefore, they are particularly suitable for the synthesis of low molecular weight polymers.

The polymerization can be carried out in a conventional manner in a C4 fraction without additional solvents or depending on the concentration of butadiene in solution by the addition of non-polar solvents such as benzene, toluene, n-hexane, n-heptane, cyclohexane or gasoline fractions. It is preferred to work without additional solvents so that the non-polymerizing C4 components of the fraction form a diluent.

The polymerization can be carried out at temperatures of from 198 to 423 K, preferably from 263 to 373 K, at atmospheric pressure or at elevated pressure. The polymerization time is generally 1-3 hours. The amount of initiator used depends on the desired molecular weight of the polymer, because it is a stoichiometric polymerization.

According to the invention, very high molecular weight polymers, for example 200,000 but also very low molecular weight, for example 1000 to 10,000, can be prepared. Of course, butadiene ikopolymers can be prepared by the addition of suitable anionic copolymerizable monomers such as isoprene, styrene or alpha- styrene, which is added to the C 1 - fraction.

The active ends of the chains of the resulting living polymers can be functionalized in a known manner by electrophilic reagents comprising ring-like groups such as carbon dioxide, alkyl enoxide, epichlorohydrin or gamma-butyrolactone to form telechelic polymers. No interruptions occur during the polymerization, so that after

Claims (2)

High-functionality telechelic polymers are produced by 240556 active polymers. The products prepared by the process of the invention have the same properties as when using pure butadiene-1,3, thereby providing a convenient and inexpensive method for producing polybutydienes with or without functional end groups. a costly process for extracting butadiene from the C4 fraction. In addition to the known processes, a more suitable low molecular weight higher functional organolithium initiator is used, which has a higher efficiency, allowing a wider adjustment of molecular weights with a lower molecular weight distribution. The resulting polymers have higher functionality. The resulting star-shaped polymers have a lower viscosity than the linear polymers, thereby facilitating the processability of the polymer. A particular advantage of the process according to the invention is that reactive polymers can be prepared with a preset functionality higher than 2, since the functionality of the polymer corresponds to the functionality of the initiator and is about 4. These polymers can be easily cured by bifunctional crosslinking agents. The process of the invention is further illustrated by the following examples. EXAMPLE 1 30 mmol of a tetralithium initiator, obtained from 60 mmol of dilithiumoligobutadiene containing an average of 4 units of butadiene, and a molecule of 30 mmol of m-divinylbenzene suspended in a 1.1 liter mixture of toluene with tetrahydrofuran (80:20 by volume), can be introduced into a sealed tube. 387.5 g of C4 fraction containing 40% by weight of butadiene-1,3 were added gradually at 263 K. Polymerization was completed in 3 h. Then 144 mmol of ethylene oxide was added to the mixture while the solution was immediately added. geloval. After hydrolysis with 50 ml of water, the solution was again well flowing. The reaction was depressurized and warmed to room temperature. After separation of the aqueous phase, 1.55 g of di-tert-butylcresol was added to the toluene solution and then the solvent was removed. A process for the selective polymerization of butadiene - 1.3 of C4 fractions with organoalkalokic initiators, in particular lithium initiators, low to medium molecular weight live polymers followed by functionalization of living polymers by electrophilic agents, especially alkylene oxides, carbon dioxide or gamma -butyrolactone, characterized in that the polymerization is carried out in a C4 fraction in the presence of a suspension of tetralithium initiators which have been prepared by reaction of O-, m- or div-divinylbenzene or mixtures thereof with a hydrocarbon solution of dilithium compound; evaporator. An average molecular weight polybutadiene of 5,250 was obtained, with a theoretical value of 5,200, with a functionality of 3.9. Infrared spectroscopy microstructure was 89 mol. % 1,2- and 11 mol. % 1,4-polybutadiene. EXAMPLE 2 A suspension of 35.3 mmol of tetralithium initiator prepared by reaction of 70.6 mmol of dilithium-oligoisoprene containing an average of 2 iso-prene units per molecule was added to a glass autoclave together with 35.3 mmol of p-divinylbenzene in 1.4 liters of benzentetra-hydrofuran mixture with a volume ratio of 90: 10 and 320 g of C4 fraction containing 37.5 wt. % butadiene-1.3. The reaction mixture was stirred at 323 K for 2 h and then functionalized with 170 mmol of ethylene oxide. After working up as in Example 1, 118 g of liquid polybutadiene were obtained having a molecular weight of 3500 with a hydroxyl content of 1.85 wt. % and 3.8. EXAMPLE 3 300 g of C4 fraction containing 35 wt. % of butadiene-1,3 was polymerized with 47.7 mmol of tetralithium initiator obtained from 47.7 mmol of m / p-divinylbenzene mixture containing 70 wt. % m-, 30 wt. % divinyl benzene and 95.4 mmol dilithiumbutane in methyl tert-butyl ether. The polymerization was carried out at 2 hp 343 K. Then functionalization was performed by adding 230 mmol of ethylene oxide. After the usual work-up, a 100% low molecular weight polybutydene containing 55 mole% 1,4- and 45 mole was obtained. % 1,2-structure. The average molecular weight was 2250. The hydroxyl content determined by the acidometric titration was 2.91 wt. %. From this, the functionality is 3.85. in particular the dilithium adduct to butadiene-1,3 isoprene containing 1 to 7 pulp units or dilithium butane at a molar ratio of divinylbenzene to dilithium compound 1: 2 in a hydrocarbon solvent, especially benzene or toluene, or all of these hydrocarbons with ether, especially ethyl ether, methyl tert-butyl ether or tetrahydrofuran, at a temperature of 198 to 423 K. 2. A process according to claim 1, wherein the polymerization is carried out at a temperature of 263 to 373 K.