SU447878A1 - Method of preventing polymerization of diolefin hydrocarbons - Google Patents

Description

(54) METHOD FOR PREVENTING POLYMERIZATION OF DIOLOPHIN HYDROCARBONS

one

A method is proposed for preventing the polymerization of diolefins. Hydrocarbons in the process of their separation, for example butadiene and isoprene, from mixtures of hydrocarbons containing them by extractive distillation and / or liquid-liquid extraction in the presence of a selective solvent, for example dialkyl substituted carboxylic amides, by adding an inhibitor based on nitrogen-containing phenol derivative.

There is a known method of preventing the polymerization of diolefinic hydrocarbons by adding various compounds and their mixtures as inhibitors, for example, nitrogen-containing phenol derivatives, to isolate butadiene and isoprene from mixtures of hydrocarbons (by extractive distillation and / or liquid-liquid extraction in the presence of field solvents, for example, Nmethylpyrrolidone, acetonitrile, dimethyl sulfoxide, dimethylformamide.

These inhibitors sufficiently slow the polymerization of diolefins in the course of their isolation. However, when using a number of solvents, for example dialkyl-substituted amides of carboxylic acids, decomposition products are formed which have

corrosion activity, which known inhibitors are not eliminated.

The purpose of the invention is to develop a method to prevent both polymerisation and corrosion in the process of isolating diolefins.

This goal is achieved by using as a inhibitor a mixture of N-methyl-p-aminophenol with 1,4-dihydroxybenzene or 3,4, 5-trihydroxybenzoic acid, or 1-feiyl-3-pyrazolidone or a mixture of 1-fai) 1l- 3-pyrazolidoia with 1,4-dihydroxybenzene or 3,4,5-trigndroxybeisoic acid with a weight ratio of comioientosis in a mixture of 1: 3-3: 1, preferably 1: 1.

The concentration of inhibitor in the process, it is advisable to maintain 0.01-5%, mainly 0.1%, by weight of the solvent. As an inhibitor of the mixture, they can significantly decrease both the polymerization of diolefins and the corrosion in the process. The effectiveness of the inhibitor mixtures and the synergistic effect that appears when they are used are confirmed by examples. In the examples, the study of the retardation of polymerization of individual components as well as of the use of inhibitor mixtures by dilatometric studies of the polymerization reaction is carried out.

The effect of a polymerization retardant can be determined visually in dilatometers made of glass. As an experimental value of the effect of substances slowing down the polymerization, the P number was taken equal to the ratio of the deceleration time to the rise of the curve.

Butadiene or isoprene and the solvent is fed in a ratio of 1: 7 and 1: 5 according to FIG. Figure 1 shows the dilatometric curve obtained using a mixed inhibitor of butadiene-dimethylformamide with the addition of a mixture of N-methyl-amiophenol sulfate and 3,4,5-trihydroxybenzoic acid (1: 1); in fig. 2 for comparison, the results obtained in experiments without

Example 3. Dimethylacetamide was used as a solvent, and butadiene-1,3 as a diolefin. The inhibitor concentration is 0.1 wt. % The temperature in the dilatometer is 90 ° C. The results are shown in Table. 3

Example 4. Dimethylformamide was used as the solvent, and butadiene-1,3 as the solvent. The inhibitor concentration is 0.1 wt. % The temperature in the dilatometer is .90 ° C. The results are shown in Table. four.

but. Anticorrosive properties of substances examined on samples of boiler steel at 150 ° C. The solvent contains water in an amount of 1 vol. %

Example 1. Dimethylformamide is used as a solvent, 1,3-butadiene is used as a diolefin. The inhibitor concentration is 0.1 wt. % The temperature in the dilatometer is 90 ° C.

In tab.

I presents data on the anticorrosive inhibitory effect of ingsional inhibitors.

Table 1

inhibitor additives (butadiene-dimethylformamide without inhibitor additives). Example 2. The solvent used is dimethylformamide, as diolefine-butadiene-1, 3. The inhibitor concentration is 0.1 wt. % The results are shown in table 2.

table 2

Example 5. Dimethylformamide is used as a solvent, and isoprene is used as a diolefin. The inhibitor concentration is 0.1 wt. % The temperature in the dilatometer is 90 ° C. The results are shown in Table. five.

Example 6 Diethylformamide was used as a solvent, and butadiene-1,3 as a diolefin. The inhibitor concentration is 0.1 wt. % The temperature in the dilatometer is 90 ° C. The results are shown in Table. 6

Table 3

Table 4

Table 5

Table 6

Subject invention

1. A method of preventing the polymerization of diolefinic hydrocarbons in the process of their isolation by extraction or extractive distillation in the absence of a selective solvent, for example dialkylsubstituted, carboxylic acid amides, by introducing an inhibitor based on a nitrogen-containing phenol derivative, characterized in that As an inhibitor, a mixture of N-methyl-p-aminophenol with 1,4-dihydroxybenzene or with 3,4,5-trihydroxybenzoic acid, or with 1-phenyl-3-pyrazolidop or mixed s-phenyl-1 H-pirazolidona s, 1,4-dihydroxybenzene or 3,4,5-trigidroksibenzoynoy acid at a weight sootnoschenii component B of 1: 3-3: 1.

2. Method 1, characterized in that the mixture is preferably used at a weight ratio of 1: 1.

3. Method according to paragraphs. 1 and 2, characterized in that the inhibitor concentration in the process is advantageously maintained between 0.01 and 5% by weight of the solvent.