SU414242A1 - Method of inhibiting terpolymerization of conjugated dienes - Google Patents

Description

one

This invention relates to the inhibition of polymerization of conjugated dienes during their isolation and purification.

It is known that during distillation of hydrocarbon mixtures containing conjugated diene hydrocarbons, in boilers of distillation columns, due to the high temperature, the polymerization of diene hydrocarbons is intense, leading to clogging of boilers with solid polymers, and in some cases of plates of distillation columns.

In order to prevent the polymerization of diene hydrocarbons, polymerization inhibitors are commonly used. As inhibitors, compounds of a number of secondary aromatic amines, phenols and their derivatives are most often used. However, the known inhibitors are not sufficiently effective; the polymer formed in their presence is both solid material that clogs the equipment.

A method for inhibiting the terpolymerization of diene hydrocarbons using aluminum trialkyls is proposed. The use of the latter as an inhibitor can significantly reduce the polymerization of diene hydrocarbons. The organo-aluminum compounds used as terpolymerization inhibitor are molecular weight regulators of the polymer formed. In the presence of organoaluminium compounds, extremely liquid polymers are formed. This completely eliminates the possibility of blocking the equipment with polymeric materials and NM and.

Example 1. The inhibitory activity of triisobutylaluminium is determined by the amount of polymer formed upon heating of isoprene with 6 wt.% Of triisobutylaluminium. To compare, a similar study was conducted with a known terpolymerization inhibitor — with tertiary butylpyrocatechin.

Heating is carried out in glass ampoules.

with a capacity of 100 ml, which load 34 g

isoprene and 2 g of triisobutylaluminum in the current

argon.

The content of the polymer after heating is determined by distilling non-polymerization isoprene under vacuum (residual pressure of 2-5 mm Hg) for 6 hours without heating, and then at 60 ° C for 6 hours and at 120 ° C for 12 hours. Polymerization rate is determined by

the ratio of heavy residue (taken as polymer), minus the amount of inhibitor, to the weight of the loaded isoprene.

Examples of calculation. a) Experience without an inhibitor.

The amount of heavy residue is 0.394 g. The percentage polymerization of iso-crene is

0.394-100

 1.16 weight. % 34

b) Experience with an inhibitor - 2 g of triisobutylaluminium.

The amount of heavy residue is 2.157 g. The percentage of isoprene polymerization is

(2.157-2.0) .100 „. 34

The results of the experiments are given in table. one.

Table 1

Polymerization of isoprene in the process of heating at 80 ° C for 65 hours

table 2

Polymerization of piperylene in the process of heating at 80 ° C for 65 hours

Triethylamine take in the amount of 2 wt.% From isoprene.

The results of the experiments are given in table. 3

Table 3

Piliemeri isoprene in the process of heating at 80 ° C for 65 hours

Example 2. The inhibitory activity of tripropyl aluminum during thermopolymerization of piperylene is determined analogously to example 1. Tripropyl aluminum is taken in an amount of 1% by weight of niperylene.

The results of the experiments are given in table. 2

Example 3. The inhibitory activity of triethylaluminum during ternolimerization of isoprene was determined as in Example 1.

Subject invention

A method of inhibiting the ternolimerization of conjugated dienes in the process of their isolation and purification by introducing inhibitors, characterized in that, in order to prevent the formation of a solid polymer, aluminum trialkyls are used as an inhibitor.