SU151325A1 - Method for liquid-phase oxidation of paraffin hydrocarbons with air oxygen - Google Patents

Description

Methods are known for the liquid phase oxidation of paraffinic hydrocarbons with atmospheric oxygen. The disadvantage of these methods is the relatively low yield and the presence in the oxidation products of ether compounds. In order to increase the yield of the product, a method is proposed which is characterized in that the oily compounds that are extracted from the liquid phase oxidation cycle are subjected to secondary oxidation with air oxygen in an aqueous alkaline medium.

According to the proposed method, the liquid paraffins of the fraction boiling at 270-350 ° are oxidized by atmospheric oxygen at atmospheric pressure in foam mode 1 at a temperature of 145 ° in glass; 45 mm diameter column with a porous glass grille for air distribution.

The linear velocity of the air is 1.1 cm / sec. When the predetermined oxidation depth is reached, a continuous withdrawal from the reaction zone of the okoidate begins, which has the following characteristic:

acid number107

sapling number 192

ether number85

carbonyl number 87

hydroxyl number71

oxyacid content 10% weight.

This oxidate is treated with a 5% aqueous solution of alkali in a weight ratio of 1: 4.

After separation from the soap solution, the raw materials with an appropriate amount of additive are returned to the reoxidation. Soap solution is oxidized with oxygen for 6 hours.

 151325 - 2 at a temperature of 130 ° and a pressure of 50 at. After a specified time, the oxidation is stopped and the resulting soaps are treated with an acid: an acidic reaction.

After settling, the top layer is separated, which is carboxylic acids, which have the following characteristics:

content of acidification - absent

acid NUMBER- 248

sapling number -256

essential number- 8

hydroxyl number- 8

carbonyl number- 5

From the aqueous solution after distillation of water-insoluble carboxylic acids, dicarboxylic acids are extracted with a solvent, which are a completely white crystalline product and have the following characteristic:

acid number is 600

sapling number -611

essential number- 11

hydroxyl number - 6

carbonyl number - 8

The molecular composition of dicarboxylic acids (% by weight.):

€ 7-10- 37.4

Sat- 20.7

Co-A9,3

S., - 22,6

During the cycle, 51.4% of the saponified compounds are extracted from the oxidate. After oxidation in an aqueous-alkaline medium, 45.8% of water-insoluble carboxylic acids and 32.5% of dicarboxylic acids are obtained for the saponified compounds derived from the cycle.

The proposed method allows to increase the yield and quality of products, as well as to jointly obtain aliphatic carboxylic and dicarboxylic acids.

Subject invention

The method of liquid phase oxidation of paraffinic hydrocarbons with atmospheric oxygen, characterized in that, in order to jointly obtain aliphatic carboxylic dicarboxylic acids and increase the yield and quality of target products, the oiled compounds are subjected to additional oxidation by air oxygen and aqueous alkaline medium.