Method of inhibiting hydrolysis of dimethylformamide or dimethylacetamide in the processes of isolation of diene hydrocarbons by extractive distillation

 

(57) Abstract:

Method of inhibiting hydrolysis of dimethylformamide or dimethylacetamide in the process of selection of diene hydrocarbons from C4-C5hydrocarbon mixtures by extractive distillation derivatives research with unsaturated carbonyl compounds or a mixture of them with morpholine. The mass ratio of morpholine: the product of its interaction with the carbonyl compound is changed in a wide range: from 0.1 to 99.9% to 99.9-0.1 wt.%. The optimal dosage of the inhibitor of 0.1-5, 0 wt. % extractant. Introduction in the extractant of the research and/or products of interaction of research with unsaturated carbonyl compounds increases the effectiveness of the inhibition of the hydrolysis of extragenic. 1 tab.

The invention relates to methods of inhibiting hydrolysis of dimethylformamide (DMF) or dimethylacetamide (DMAA) in the processes of isolation of diene hydrocarbons from C4-C5hydrocarbon mixtures by extractive distillation (ER) and may find application in the petrochemical industry for the production of diene hydrocarbons.

In the process of extractive distillation for solvent use various organic is aetsa hydrolytic instability.

To prevent hydrolysis of the extractants used inhibitors. Usually the role of the latter perform aliphatic and aromatic carbonyl compounds (ed. N 307996, class C 07 C 7/10, 1969). In the domestic industry, in particular in the processes of isolation of diene hydrocarbons have been used cyclohexanone and furfural (liokumovich A., and others, the Inhibition of hydrolysis of dimethylformamide.-Chem. industry, No. 3, 1970, S. 22-24).

The main shortcomings in the industry inhibiting compositions are insufficient efficiency of inhibition, loss of extractant and inhibitors with heavy resins.

The purpose of the invention is improving the efficiency of inhibition of the hydrolysis of extractants.

This goal is achieved by introducing into the extractive agent as an inhibitor of the research and/or products of interaction of research with unsaturated carbonyl compounds of General formula

,

where

R1= H, C1-C12; R3-CO-R4(R3and R4= C1-C10;

R2= C1-C12; R3-CO-R4(R3and R4= C1-C10)

Components inhibitor soluble in DMF, DMAA, are the inhibitor is nil economic expediency.

The advantages of this method are the ease of preparation and dosage of the inhibitor.

In addition, the physical properties of the research (TKip.= 128oC) reduce the loss of inhibitor heavy resins.

Example 1 (control experiment).

In a glass three-neck flask with a capacity of 500 ml equipped with a thermometer and reflux condenser, download dimethylformamide containing 10 wt.% water and 0.1 wt. % formic acid (HCOOH - catalyst in the hydrolysis of DMF). Refrigerator connected to a system of flasks Drexel filled titrated with an aqueous solution of acid or water to absorb the product hydrolyse DMF-dimethylamine, which is then subjected to analysis. Studies of the hydrolysis of DMF is carried out at a temperature of 150oC and atmospheric pressure. The duration of the experiment 135 hours On the degree of hydrolysis of DMF is judged by the amount of released dimethylamine and formic acid, followed by conversion to DMF. The results are presented in the table.

Example 2 (the prototype). In the conditions of example 1 determine the degree of hydrolysis of DMF containing 10 wt.% water; 0.1 wt.% HCOOH and 1.0 wt.% furfural. The results are presented in the table.

Example 3.

Example 4.

In the conditions of example 3 instead of the research as an inhibitor of the hydrolysis of DMF using 1-morpholinomethyl-1,3 in the amount of 1.0 wt.%. The results are presented in the table.

Examples 5-9.

In the conditions of example 3 instead of the research as an inhibitor of the hydrolysis of DMF using 1.0 wt.% a mixture of morpholine + 1-morpholinomethyl-1,3 in the following mass ratios: 99,9+0,1; 90 + 10; 50 + 50; 10 + 90; 0,1 + 99,9. The results are presented in the table.

Example 10.

In the conditions of example 3 instead of the research as an inhibitor of the hydrolysis of DMF using 4-morpholinomethyl-2 in the amount of 1.0 wt.%. The results are presented in the table.

Examples 11-15.

In the conditions of example 3 instead of the research as an inhibitor of the hydrolysis of DMF using 1.0 wt.% a mixture of morpholine + 4-morpholinomethyl-2 in the following mass ratios: 99,9 + 0,1; 90 + 10; 50 + 50; 10 + 90; 0,1 + 99,9. The results are presented in the table.

Example 16.

In the conditions of example 3 instead of the research as an inhibitor of the hydrolysis of DMF using 1,3-dimorpholino in the amount of 1.0 wt.%. The results are presented in the table.

Examples 17-21.

In the conditions of example 3 instead of the research as in eniah: 99,9 + 0,1; 90+10; 50 + 50; 10 + 90; 0,1 + 99,9. The results are presented in the table.

Examples 22-23.

In the conditions of example 3 instead of the research as an inhibitor of the hydrolysis of DMF using 5.0 wt.% a mixture of morpholine + 1,3-dimorpholino in the following mass proportions: 90 + 10; 50 + 50. The results are presented in the table.

Example 24.

In the conditions of example 3 instead of the research as an inhibitor of the hydrolysis of DMF used to 0.10 wt.% a mixture of morpholine + 1,3-dimorpholino in a mass ratio of 10+90. The results are presented in the table.

Examples 25-27.

In the conditions of example 1 determine the degree of hydrolysis DMAA containing 10 wt. % water; 0.1 wt.% CH3COOH and 1.0 wt.% a mixture of morpholine + 1,3-dimorpholino in the following mass ratios: 90 + 10; 50 + 50; 10 + 90. The results are presented in the table.

From the table it is seen that the interaction products of the research with unsaturated carbonyl compounds such as 1-morpholinopropan -1,3, 4-morpholinomethyl-2, 1,3-dimorpholino, etc. are more effective inhibitors of the hydrolysis of DMF or DMAA than furfural, and the use of mixtures of the research and its derivatives is observed synergistic effect.

hydrocarbons from C4- C5-hydrocarbon mixtures by extractive distillation in the presence of these extractants by the introduction of a hydrolysis inhibitor, characterized in that as an inhibitor use morpholine or its derivative selected from a range that contains 1-morpholinopropan-1,3,4-morpholinomethyl and 1,3-dimorpholino, or a mixture of the research with the specified derivatives of the research in their mass ratio of from 0.1: to 99.9 to 99.9: 0.1, respectively in an amount to provide its concentration in the extractant is 0.1 to 5.0 wt.%.

 

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