SU386907A1 - METHOD FOR ISOLATION OF FORMIC ACID - Google Patents

Description

one

This invention relates to an improvement in the process for isolating formic acid from a mixture with other carboxylic acids.

There is a known method for isolating formic KI1SLOTS from its mixture with other carboxylic acids by esterification with liquid alkyl alcohols and subsequent distillation.

The disadvantage of this method is high energy costs, the need for dehydration, since ethers tend to form azeotrons, as a result of which it is impossible to obtain a high quality product.

According to the proposed method, a mixture of carboxylic acids containing formic acid is treated with isobutylamine.

The method is carried out by liquid extraction.

As a-olef "a (Isobutylene is used with a particularly high selective ability. At the same time, the interaction of isobutylene with formic acid proceeds according to the coordination principle and does not lead to the formation of gret-butalformate IB in any significant amounts.

Example 1. A mixture containing 5 wt. % formic and 95 wt. % acetic acid, is subjected to five-step extraction by cross-flow of a mixture of acids and isobutylene with (weight ratio (at each stage) isobutylene: acid sour T 3: 1. The final content of formic acid in acetic acid is 0.005 wt.%.

Isobutylene, containing 2.5 wt. % formic acid, incubated for 20 hours, then distilled npii by heating the mixture to 45 ° C.

The concentration of the basic substance in formic acid is 99.8 wt. %

Example 2. Under the conditions of example 1, a mixture containing 7 wt. % ant, 80 wt. % acetic acid and 13 wt. % iroionic acid.

The final content of formic acid in a mixture of carboxylic acids is 0.01 wt. %

Subject invention

A method for separating formic acid from a mixture of carboxylic acids, which is characterized by TeiM, is used to treat the mixture of carboxylic acids with isobutylene followed by distillation in order to simplify the process and obtain a high-quality product.