DD265150A1 - PROCESS FOR PREPARING HIGH 1,4-CIS-CONTAINING POLYBUTADIENES - Google Patents

Abstract

The invention relates to a process for the preparation of polybutadiene having a high 1,4-cis content and high elasticity by polymerization of butadiene in the presence of a suspended catalyst mixture comprising a Ni (O) component or nickel carboxylate and an organometallic compound, preferably AlEt 3 and amorphous AlF 3 contains as cocatalyst.

Description

Characteristic of the known technical solutions

It is known to polymerize diolefins in the presence of catalysts formed by reacting a transition metal compound with compounds having metal-carbon and / or hydrogen-hydrogen bonding. These catalysts form the basis of the Ziegler catalyst systems used to make high 1,4-cis polymers

 It is also known that metal carbonyls by reacting with organometallic compounds and / or Lewis acids!

Similar catalysts (DE-PS 1156986, Japanese Patent 17 687/62, DD-PS 52 817, DD-PS 56 640) result. According to DD-PS 65 565 | Metal (O) - and MetalKD compounds of the 8th subgroup of the PSE in combination with Lewis acids for the preparation of:

Monoolefins used. I

When using these catalyst systems mentioned arise products that do not fully meet the requirements for good processing capability due to their high gel content, the low J stereoregularity and narrow molecular weight distribution.

Furthermore polybutadiene can be obtained with 97% 1,4-cis units, when the polymerization of butadiene is carried out in an organic solvent at 4O ⁰ C in the presence of a catalyst system which is prepared by mixing nickel naphthenate, boron trifluoride etherate and triethylaluminum (US Pat. No. 3,496,965, US Pat. No. 3,474,462), wherein the molar ratio of trialkylaluminum to boron trifluoride etherate is between 0.1 and 5 and that between nickel salt and trialkylaluminum is between 0.03 and 7. Disadvantage of this method is that the catalyst system is not completely soluble in hydrocarbon. On the other hand, the catalyst activity decreases when impurities are present in the polymerization system or the monomer concentration is low.

According to US Pat. No. 3,471,462, in analogy to US Pat. No. 3,170,907, the catalyst is preformed in the presence of small amounts of conjugated diolefins. The butadiene is added here as a liquid component of the mixture before the nickel salt and the Motallorgani8Che compound are mixed together. The catalyst aging takes place at 20 to 100 ⁰ C. ι

According to US Pat. No. 3,464,965, the catalyst mixture is aged for at least 16 minutes. US Pat. No. 4,020,255, DE-OS 2616953, US Pat. No. 3,474,462 disclose improved processes wherein the catalyst must be made available in situ to avoid catalyst deposits. The catalyst must be suspended or dispersed because it is insoluble. The insolubility of the catalysts results e.g. to blockages of the supply lines. The preforming of such catalyst systems using conjugated diolefins as catalyst stabilizers (US Pat. No. 3,464,965, US Pat. No. 3,474,462) does not provide a satisfactory catalyst system. Since the presence of butadiene, the possibility exists of oligomeric crosslinking and thus gelation and settling of the catalyst in the supply pipes or reactors and occurs.

Object of the invention

The aim of the invention is! the preparation of highly 1,4-cis-containing polybutadiene with a gel-free catalyst, without diolefins, ζ. B. butadiene can be handled as a stabilizer. The space-time yield should be increased and the raw rubber should have increased elasticity.

Explanation of the essence of the invention

The object of the invention is to develop a process for the preparation of polybutadiene having a high 1,4-cis content by altering the catalyst system.

According to the invention the object is achieved in that the catalyst mixture is a combination of a Ni (O) component, preferably Ni-bis-cyclooctadiene 1.5 (NI (COD) ₂ ) or Ni-cyclododecatriene (Ni ⁰ CDT) or Ni-carboxylate ( Nl (acac) ₂ ) and an organometallic compound, preferably AIEt ₃ and amorphous AIF _{3 is used} as catalyst support component. To prepare the catalyst, each individual catalyst component is dosed separately into the catalyst aging vessel. When using Ni-carboxylates, it is expedient that an AIF ₃ wet suspension is introduced and to the dissolved Ni component and the organometallic compound, preferably AIEt _{3 is} given.

The aging time of the catalyst is 5 to 35 min at a temperature between 0 and 100 ⁰ C. The aging takes place without the addition of diolefins or butadiene.

The molar ratio of the catalyst components to one another must be maintained within the following limits:

Ni: AIF ₃ VOn 1: 5 to 1: 500 and

Ni: AIEt ₃ from 1: 0.3 to 1:30.

It has surprisingly been found that amorphous AIF ₃ in combination with nickel compounds of lower oxidation states or Nickeicarboxyiate and AIEt ₃ , without supplying in the catalyst forming phase butadiene ict, hochmoiekulares highly cishaltiges polybutadiene provides.

It is further advantageous that these catalyst combinations are substantially less sensitive to impurities in the polymerization system.

The space-time yield increases by about 50%, the obtained polybutadienes are characterized by a high linearity and high elasticity (56 to 60% resilience) from. Another advantage is that the gel and Stipponbiidung is avoided in the product. Since the catalyst is formed without addition of butadiene, the previously disturbing deposits no longer occur.

embodiments

Using exemplary embodiments, the subject matter of the invention is explained in more detail without restricting it.

example 1

In a Schlenk vessel is likely 9.25 x 10 _"3 mole AIF are initially charged, to 50 ml of a solution of 9.26 toluenischen 10" ⁵ mol Ni ⁰ CDT can, aging at room temperature for 35min, are to 500ml Toiuen and then polymerized at 50 ⁰ C in an autoclave using 50g of butadiene. Within 2 hours one reaches quantitative conversion. The polymer contains 98% 1,4-cis units with an intrinsic viscosity of 3dl / g.

Example 2

Procedure as in Example 1. As the nickel component is used 9.25 10 ~ ⁶ moles of Ni (COD). 2 After aging at 80 ⁰ C for 35 min and subsequent polymerization is obtained within 2 h in quantitative yield, a polybutadiene with 98% 1,4-cis units at an intrinsic viscosity of 1.8 dl / g.

Example 3

Procedure w <? in Example 1. As nickel component used 9.25 10 ~ ⁶ moles of Ni (acac) ₂ . To this is added 9.25 10 ~ ⁴ mol AIEt ₃ in 20 ml Toiuen. After an aging time of 35 min at room temperature, polymerization is carried out at 80.degree. Within 2 h is obtained in quantitative yield, a polybutadiene with 97% 1,4-cis units and an intrinsic viscosity of 2.9dl / g. In none of the cases occurs during catalyst aging on a deposition of gel-like approaches.

Claims (1)

Process for the preparation of high 1,4-cis polybutadiene by polymerization of butadiene in the presence of a catalyst mixture of a Ni (O) component, preferably Ni-cis-cyclooctadiene 1,5 or Ni-cyclododecatriene, suspended in an organic solvent, or nickel carboxylate and an organometallic compound, preferably AIEt ₃ , characterized in that is used as the cocatalyst amorphous AIF ₃ in a molar ratio of 5: 1 to 500: 1 to the Ni component. Field of application of the invention The invention relates to a process for the preparation of highly 1,4-cis-containing polybutadiene, preferably for tire production.