DD228551A1 - METHOD FOR THE CATALYTIC SOLUTION POLYMERIZATION OF 1,3-BUTADIENES - Google Patents

Abstract

The novel process for the stereospecific polymerization of 1,3-butadiene in a toluene solution in the presence of organometallic catalysts leads to an increase in the space-time yield. According to the invention, 0.01 to 0.05% of cyclooctadiene is added to the solvent Toluen or the Ruecktoluen obtained in the workup of the polymer, in which cyclooctadiene is included, added to the fresh olive in an appropriate amount to ensure the above Cyclooktadienkonzentration. The physical and utility properties of the rubber are not compromised.

Description

Title of the invention

Process for the catalytic solution polymerization of 1,3-butadiene

Fields of application of the invention

The invention relates to a process for the catalytic solution polymerization in toluene for the preparation of the stereo-rubber 1,4-cis-polybutadiene.

This rubber is particularly suitable for the treads of vehicle tires, as it over SBR and natural rubber has significant advantages such. B. higher abrasion resistance, lower gas permeability, higher bending, tear strength and better electrical properties.

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Characteristic of the known technical solutions

Since the beginning of the βθ-iger years poly-cis-butadiene is prepared by Ziegler-Natta catalysts or Philips catalysts on an industrial scale by the solution polymerization process. In general, combinations of aluminum alkyl halides with organically soluble heavy metal complex compounds are used (Saltmann, W.M., Kuzma, L.I .: Chem. Technol., 1973, 1055).

The chosen catalyst system predominantly determines the stereospecific orientation of the polymer. For ER-) submission of a maximum 1,4-cis content, the catalyst complexes AlR ₂ COCl _2, TiCl ^ -AlRo-I ₂ Hi and complexes are particularly suitable.

The use of various solvents is described in numerous patents. So z. B. in DE-AS 1420456 as suitable solvents saturated alkanes such as butane, hexane, heptane, individually or in admixture, deobase kerosene, or benzene hydrocarbons such as benzene, toluene or cycloalkanes such as cyclohexane, methylcyclohexane recommended. It is apparent from this application that the absence of oxygen, water, peroxides, dihydric sulfur compounds and various other impurities is very important to the polymerization.

It has been known since the mid-40s that butadiene dimers and other high-boiling hydrocarbons retard or negatively affect the polymerization of butadiene (Robey, RF, et al., Ind. Eng. Chem., 36, -3, 1944) ). The formation of dimers can u. a. during storage of the butadiene or during the recovery stages.

At the present time, the most effective catalyst for the stereospecific butadiene polymerization is a three-component catalyst, e.g. b. aluminum triethyl, nickel naphthenate and boron trifluorodiyl etherate in aromatic solvents. When using aliphatic solvents, the catalyst preparation can be prepared from the three individual components in

done in situ.

The use of toluene for the polymerization of 1,3-butadiene to 1,4-cis-polybutadiene is described in several Japanese patents and by G.V /. Poehlein and D.I. Dougherty in Rubber Chein. Technol. 50, pp. 601-638 (1977).

The requirements for the highest degree of purity of toluene are contained in the TGL 26812/02 for the so-called pure toluene 1. The following criteria are listed: Sulfuric acid reaction max. »0,3 g / l> Bromine consumption max. 0.1 g / l, evaporation residue max. 5 mg / 100 ml, free from active sulfur. Since no conclusions can be drawn on the suitability of the toluene for the polymerization on the basis of these criteria, it is customary to determine this by a laboratory test polymerization. For this purpose, the so-called. Piaschepolymerisation is particularly suitable. The control is carried out by sales determination and is then available as an operational specification with the appropriate solvent as standard. Although the causes of polymerization delays are mostly known, it is still unclear why polymerization under identical conditions with the same catalyst system and toluene as a solvent with the same analytical indexes is sometimes faster than the standard polymerization.

Object of the invention

The aim of the invention is to increase the speed of the known stereospecific polymerization of 1,3-butadiene to cis-polybutadiene in solvent toluene, without adversely affecting the physical characteristics of the rubber and thus its utility properties. The increase in the reaction rate should always remain the same, the economics of the production of cis-polybutadiene should be improved.

Explanation of the essence of the invention

The invention is the. The object of the invention is to develop a process for the catalytic solution polymerization of 1,3-butadiene in toluene using known catalyst systems with the aid of suitable additives, the above requirements being intended to be ensured.

The object is achieved in that in a conventional manner 1,3-butadiene is polymerized in toluene in the presence of a known catalyst system, wherein the toluene 0.01 to 0.05 % cyclooctadiene are added. Cyclooctadiene is formed during the recovery of the toluene in the final stage of the polymerization process, so that it is expedient to blot this Rücktoluen with known Cyclooktadiengehalt with so much Frisch Toluen that the content of the cyclic butadiene dimer according to the invention in the toluene mixture is 0.01 to 0.05 % . It has been found that the cyclooctadiene concentrations mentioned act so activating on known catalyst systems that with the same amount of catalyst up to 10% more 1,3-butadiene can be polymerized without the physical or utility properties changing noticeably. The plague that this amount of cyclooctadiene, which in principle is present in traces, exerts such a control effect on the polymerization rate or the effectiveness of the catalyst system is surprising to the person skilled in the art, since butadiene dimers are known as polymerization retardants (Robey, RF, et al., Ind. Eng. Chem., 36, 3 (1944)). This delay in polymerization occurs, but only at concentrations of more than 0.05 % cyclooctadiene in toluene.

Although the effect of the cyclooctadiene mentioned occurs more or less strongly in any known stereospecific butadiene polymerization catalyst system, it is particularly pronounced in the system of organoaluminum compounds, preferably in the tri-tri-butane, nickel naphthenate and boron trifluoride etherate three-component catalyst.

A further surprising effect has been found in the fact that the aging time of the catalyst solution required for obtaining an optimal activity is considerably shortened by the addition of cyclooctadiene according to the invention. Pur the process of the invention, neither the polymerization nor the pressure to which the catalyst solution is exposed with the butadiene, crucial. Pressures of 0.1 MPa and above or below and temperatures between - 50 ⁰ C to 100 ⁰ C can be applied. In a preferred implementation of liquid butadiene in toluene under an inert atmosphere such as nitrogen, is dissolved and under autogenous pressure of the present agents at - 20 ⁰ C to + 100 ⁰ C, preferably 50 to 90 ⁰ C, polymerized.

The inventions will be explained below with reference to exemplary embodiments.

embodiments

Pure toluene was used according to TGL 26812/02 - quality 1, which was distilled again - in the course of toluene. Toluene 1 with an addition of 0.01 % cyclooctadiene is designated toluene 2, with 0.05 % cyclooctadiene toluene 3. Three polymerizations on a laboratory scale (Examples 1 to 35 and two large-scale continuous butadiene polymerizations (Examples 4 and 5) were carried out.

Examples 1, 2 and 3

The polymerization vessels were thoroughly cleaned, dried and purged with argon. To remove any residual air and moisture, 1 ml of a 10-fold aluminum triethyl solution in toluene was introduced with an injection syringe and removed immediately before the beginning of the polymerization. As a catalyst, nickel naphthenate, boron trifluoroetherate and aluminum triethylamine were injected. After an aging of the

Catalyst at 60 ° C for 60 minutes was added to 1,3-butadiene in toluene and the polymerization temperature maintained at 40 ^° C. After 60, 90 and 120 minutes, respectively, sales provisions were made.

Table 1 summarizes the degrees of implementation of the 3 laboratory tests.

Tab. 1:

Control polymerization with: 60 sales (%) to 76 §0 120 minutes Toluene 1 (standard) 81 83 88 Toluene 2 84 87 92 Toluene 3 90 94 Examples 4 and 5

With the same catalyst system as in Examples 1 to 3, continuous polymerization experiments were carried out for several days in a large-scale production plant for the stereospecific polymerization of 1,3-butadiene. In experiment 4, distilled pure toluene 1 without additives was used as solvent; in experiment 5, toluene was added with enough back toluene that the toluene mixture contained 0.032% cyclooctadiene. Differences in the physical characteristics of both polymers were not observed; in experiment 5 with cyclooctadiene addition, the throughput of 1,3-butadiene was reduced by 6 with the same amount of catalyst solution % be increased.

A rubber mixture of the polymers of both experiments of the following composition was vulcanized at 145 C for 30 minutes. Table 2 summarizes the test results of both VuI canisates.

Compound:

(Part by mass)

Polybutadiene 100

Carbon black Ή 220 60

Stearic acid 1.5

Zinc oxide 3

Plasticizer (SE) 12.5

Protective wax 1.5

ASM IPPD 1

ASM-PBl 0.75

Accelerator CBS 0.8

Sulfur 2

Tab. 2:

try 4 Trial 5 (Invention) Tensile strength MPa 14.6 15.5 elongation 446 430 Elongation MPa 8th 9 Rebound elasticity % 44 47 Hardness (Shore A) 58 60 Mixed and Viscosity • ICL 1 + 4 (100 ⁰ C) se 74

Claims (2)

Invention claim A process for the catalytic solution polymerization of 1,3-butadiene in toluene and in the presence of an organometallic catalyst, characterized in that 0.01 to 0.05% cyclooctadiene is added to the toluene. 2. The method according to item 1, characterized in that in continuous operation, the resulting in the final phase of Butadienpolymerisation and in the recovery of toluene in this remaining cyclooctadiene with this toluene is added to the Sribtoluen »