SU899527A1 - Process for separating mixture of benzaldehyde and phenol or benzaldehyde and o-cresol - Google Patents

Description

I

This invention relates to an improvement in the method for separating a mixture of benzaldehyde-phenol or benzaldehyde-o-cresol. These substances can be used as intermediates for the preparation of antioxidants, insecticides, herbicides and fungicides.

A known method of separation of a mixture of benaldehyde-phenol by multistage extraction at 20-25 ° C with a mixture of methanol and water at a weight ratio of 1: 1, or a mixture of ethylene glycol-water at a weight ratio of 3: 1, to obtain an extract containing phenol and rafinate-enzaldehyde. The content of benzaldehyde in the extract or the initial amount of f-10% or 0.6 wt.% B The disadvantage of this method is the high content of benzaldehyde in the extractant {0.6-1 wt.%).

Most technically to the proposed is sposb separation of a mixture of benzaldehyde-phenol by two-stage distillation with

getting in the first column at a temperature at the top of the column 120-122 C and a pressure of 9O-100 mm RT. v., in the presence of VI -cresol or tricresol-smbsc cresols as an extractive agent, phenyl distillate and benzaldehyde-m-cresol bottom product or tricresol, which are separated in the second column at a temperature in the top of the column of 75-113 ° C and pressure 20 -10O mm

10 Hg Distillate-benzaldehyde and the bottom product of the composition m-cresol or tricresol-benzaldehyde feeds into the first column. The purity of the released phenol is 99-99.5%, benzpidehyde 98-99% L2J.

ts

The disadvantage of this method is that the purity of the target products is not high enough.

The aim of the invention is to increase the purity of the target products.

20

The goal is achieved by a method of separating a mixture of benzaldehydephenol or benzaldehyde-o-cresol by two-step rectification to obtain

in the first column with reMnepatype at the top of the column 48-112 ° C and pressure 4-10 O mm rg.sg. disg llaga benzal degda, which is removed from the system, and the bottom product of composition benalealdehydephenol or o-cresol, which is separated in the second column at a temperature at the top of the column 181-188 ° C and atmospheric pressure on the bottom product of composition benzaldehyde-phenol or o-cresol derived from. these themes, and distillate-h)) enol or o- resol.

The invention allows to increase the purity of the target products of benzaldehyde to 99.5-99.9%, phenol or o-cresol- to 99.6-99.8%.

Example I. 10 kg / h azeotropic mixture containing benzaldehyde-phenol. 49% by weight of benzaldehyde and 51% by weight of phenol, 50 theoretical plates are fed to the first column, where

at a temperature in the top of the column, in a cube -61 C and a pressure of 4 mm Hg. 3.61 kg / h of disTillat (the composition of benzaldehyde is 99.9 wt.%, and phenol O, 1 wt.% and 6.39 kg / h of the bottom product (composition of benzaldehyde 2O, 2 wt.% and phenol 79.8 wt. .%), which is fed to the separation in the second column (the temperature of the top of the column

 C, cube - 190C, atmospheric pressure, 40 theoretical plates). 3.79 kg / h of distillate were isolated (phenol composition was 99.8 wt.% And benzaldehyde was 0.2 wt.% And 2.6 cubic product of the azeotropic mixture of benzaldehyde-4 e-NOL (benzaldehyde composition was 49 wt.%, Phenol 51 wt.%), which is fed to the separation in the first column.

Examples 2-5. Lead process

similar to example I. Results are presented in tabtzac.

Claims (2)

Invention Formula The method of separation of a mixture of benaldehyde-phenol or beisaldehyde-o-cresop by two-sided rectification, mainly because in order to increase the purity of the target products, the initial mixture is separated in the first column at a temperature in the top of the column 48-112 ° C and a pressure of 4-100 mm Hg. distillate benzaldehyde and the bottom product of the composition phenol or o-cresol benzaldehyde, which is separated in the second The column at the temperature at the top of the column is 181-188 ° C and the atmospheric pressure on the bottom product of the composition benzaldehydephenop or o-cresol, is extracted from the system and distillate-phenol or o-cresol. Information source taken into account during the examination US Patent hfe 3850955, chl. 26О-621, publ. 11/26/74. 2. USSR author's certificate, 623851, cl. C 07 C 47/54, 10/28/76 (prototype).