Method of selective hydrogenation containing conjugated diene block copolymer

Abstract

A process for selectively hydrogenating the block copolymer containing conjugated diolefine features that the tetrahydrofuran is used as the solvent of bicyclopentadiene titanium bichloride as primary catalyst. Its advantages are low energy consumption for post-treatment as tetrahydrofuran has high solubility, low poison of tetrahydrofuran, low cost, and high hydrogenation effect.

Description

technical field [0001] The invention relates to a method for selectively hydrogenating block copolymers containing conjugated dienes. Background technique [0002] Conjugated diene-containing block copolymers mainly refer to copolymers obtained by anionic polymerization using styrene, butadiene (or isoprene) as monomers and alkyllithium as an initiator, mainly including Thermoplastic rubber SBS, SIS, etc., there are still double bonds in the soft segment of polybutadiene or polyisoprene in this type of copolymer, so the anti-aging performance is poor, and its application field is limited. In order to improve the anti-aging performance of this type of copolymer, the block copolymer containing conjugated diene is usually selectively hydrogenated, that is, under the condition of dicyclopentadiene titanium dichloride as a catalyst, the copolymer is polyconjugated The unsaturated double bond in the diene block undergoes hydrogenation reaction to make it saturated, while the benz...

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Problems solved by technology

[0003] Because the hydrogenation main catalyst dicyclopentadiene titanium dichloride is solid powder, in the prior art, U.S. Patent No. 5,291,990 adopts cyclohexane as the solvent of the main catalyst dicyclopentadiene titanium dichloride to dissolve the main catalyst In cyclohexane, then add the reaction system, because the solubility of the main catalyst dicyclopentadiene titanium dichloride in cyclohexane is very low (at 25°C, 1000ml cyclohexane can only dissolve 0.001g dicyclopentadiene dichloride Titanium chloride), according to the main catalyst required for the reaction, a large amount of cyclohexane will be added to the reaction system, generally the cyclohexane of the system will be increased by 30%, so that the energy consumption of post-treatment will be increased

[0004] Chinese patent ZL.97108258.8 adopts toluene as the solvent of the main catalyst dicyclopentadiene titanium dichloride, although the solubility of the main catalyst in toluene is greatly improved (at 25°C, 1000ml toluene can dissolve 0.9g dicyclopentadiene dichloride titanium oxide), but toluene is a kind of aromatic hydrocarbon solvent, which is highly toxic, and the boiling point of toluene at normal pressure is 110.6°C higher than that of cyclohexane at 76°C, which increases the energy consumption of post-treatment

[0005] Chinese patent 92110490.1 adopts cyclohexane suspension method to add the main catalyst dicyclopentadiene titanium dichloride, that is, the main catalyst dicyclopentadiene titanium dichloride is added in the form of solid, so there is inaccurate feeding, which makes the hydrogenation reaction difficult to control and the dissolution of the main catalyst dicyclopentadiene titanium dichloride in the reaction system needs a certain time, which reduces the efficiency of the reaction