A method for improving the yield of isopentenol by chlorination

Abstract

The invention discloses a method for improving a yield of chloridization method preparation of prenyl alcohol. The existing chlorination method for preparing prenyl alcohol produces about 10% of 3-chloroisopentene which is not a target product so that a prenyl alcohol yield is limited and more excess solid wastes are produced. The method comprises directly adding anhydrous formate or acetate into a mixture of 3-chloroisopentene and 1-chloroisopentene produced by a chloridization reaction, carrying out esterification, carrying out hydrolysis in an alkali solution so that iso-amylenol formate or iso-amylenol acetate is transformed into prenyl alcohol and 3-chloroisopentene is transformed into methyl butenol, carrying out rectification separation on the obtained organic layer to obtain methyl butenol, methylbenzene and prenyl alcohol and recycling methyl butenol and methylbenzene in a chloridization addition reaction. The method is free of the traditional chloroisopentene rectification so that the problems of equipment corrosion, chlorine substitute toxicity and high temperature-caused chlorine substitute destroy caused by chloroisopentene rectification are solved.

Description

technical field [0001] The invention relates to the field of organic chemical synthesis, in particular to a method for improving the yield of isopentenol prepared by a chlorination method. Background technique [0002] The chemical name of prenol is 3-methyl-2-buten-1-ol, which is an important fine chemical intermediate and can be used to synthesize citral, pyrethroid insecticides and other fine chemicals. At present, the main routes for synthesizing prenol are: 1) BASF patent WO2008037693, Chinese patent CN103254036, etc., using formaldehyde and isobutylene to generate 3-methyl-3-buten-1-ol through the Prince reaction, and further Isomerization produces isopentenol. 2) Chinese patents CN102924227, CN102584519, etc. use methyl butenol or isoprene as raw material, after chlorination and esterification with sodium acetate, and then further alkaline hydrolysis to obtain isoprenol. From the perspective of atom economy and cleanliness and environmental protection, the reaction ...

AI Technical Summary

Problems solved by technology

From the perspective of atom economy and cleanliness and environmental protection, the reaction of formaldehyde and isobutene to prepare prenol is a relatively good route, but this route requires high temperature and high pressure reaction conditions, the reaction conditions are very harsh, the equipment investment is large, and it has certain safety risk

And methyl butenol and concentrated hydrochloric acid chlorination addition method synthesizes isopentenol, reaction condition is gentle, equipment requirement is low, but produce about 10% 3-chloroisoamylene in the process of chlorination is not target product , which limits the yield of isopentenol, and will also generate additional solid waste, mainly because in the process of synthesizing chlorinated isopentene, 3-chloroisopentene and 1-chloroisopentene are in There is a balance in the reaction system, 3-chloroisoamyl and 1-chloroisoamyl always maintain a ratio of 1:8 to 1:9, if the conventional distillation separation method is used for separation, chloroisoamyl Unstable under heating conditions, it will further add chlorination with dissolved hydrogen chloride, and will also polymerize to produce new impurities; in addition, chloroisoamyl is relatively corrosive to equipment, and the vapor of chloroisoamyl is also Has relatively high toxicity

The existence of many factors seriously affects the separation and recovery of 3-chloroisoamylene and 1-chloroisoamylene