SU106651A1 - The method of separation of the mixtures obtained in the production of alcohols C7-C9 - Google Patents

Description

Fatty alcohols are used to make phthalic acid esters, which are high-quality plasticizers used in the production of certain types of plastic materials.

The mixtures produced in the production of fatty alcohols by hydrogenation of butyl esters of 0.7-SU fatty acids contain by-products and the isolation of the desired product (alcohols) is carried out by rectification. From the mixture resulting from the hydrogenation of fatty acid butyl esters (catalyzate), there are three fractions that follow; namely, azeotronic mixtures of butanol-hydrocarbons-water, with which all the water contained in the catalyst is distilled; butapol; alcohols Art - C).

The azeotropic butanol – hydrocarbon – water mixtures are exfoliated after condensation into two layers: the upper one, the content of the advantages of butanol and hydrocarbons with a small amount of water, and the lower water layer containing about 2% butanol and about 2% of hydrocarbons.

The separation of hydrocarbons of the upper layer and the regeneration of the content of butyl alcohol in it is carried out by adding lower alcohols Ci-C.i and water and distilling hydrohydrates as azeotropic mixtures with alcohols and water and excess water as an azeotropic mixture with butyl alcohol.

This known method has the following disadvantages:

1. In connection with those that in three-component azeotroic mixtures of butaiol-hydrocarbons-water, the molar ratios of water and hydrocarbons are bile units, and in catalyzate these properties are contained in an equimolecular: | | Since these three-compound azeotronic mixtures are indicated, then all the hydrocarbons contained in the catalyzate cannot be separated. In this case, hydrocarbons are contaminated with butanol, and high-carbon and carbon dioxide do not enter the final product, impairing its quality.

2. Application of aqueous solutions of Ci-C alcohols. to release hydrocarbons from the upper layer resulting from the condensation of azeotropic butanol – hydrocarbons – water mixtures, causes

the process of distillation with respect to large quantities of the azeotronic butanol – water mixture, the further separation of which butanol makes the separation process more expensive and expensive.

The present invention provides a method for separating mixtures obtained from the production of alcohols.

The method consists in the fact that initially all the water is distilled off from the condensate at a maximum azeotron mixture. After the water is distilled off, practically anhydrous methanol is added in a four-fold amount of hydrocarbons by weight, and then the hydrogen sulfides are distilled off as binary azeotropic mixtures with methanol, and in the vat residue you retain the almost pure butaiol. The azeotroic mixture of methanol hydrocarbons is mixed with water (15% of the water of the mixture's plummet), as a result of which stratification occurs: in the upper layer there is about 99% yi-hydrohydrogen, and in the lower layer there is a water solution of methanol.

This method allows the exception of the stage of distillation of aqueous butanol and the operation for its regeneration.

Subject invention

The method of separation of the mixtures obtained in the production of St-Ce alcohols by the azeotropic distillation method, characterized in that, in order to reduce the recycling of the alcohols and improve the separation conditions, an additive is used to these water in an amount sufficient to form a three-component azeotropic butanol mixture. water-hydrocarbon, the latter is separated by distillation of water in the form of an azeotropic three-component mixture, followed by the addition of anhydrous methanol to this mixture in an amount exceeding that necessary to isolate all the coal odorodov azeotronnyh as binary mixtures with methanol and then distilled off the hydrocarbons in the form azeotropes with methanol and isolated first by adding 15% by weight. water.