Method for the preparation of 4-chloro-2-methyl-crotonaldehyde
AssigneeAnic S.p.A.
InventorsLuciano Re, Giancarlo Eletti Bianchi, Felice Centini
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Abstract
In the preparation of 4-chloro-2-methyl-crotonaldehyde, an important starting material for the preparation of the acetate of Vitamin A, the improvement consisting in that isoprene monoepoxide (1:2-epoxy-2-methyl-3-butene) is chlorinated either with tert.butyl hypochlorite in the vapor phase, or with cupric chloride in the liquid phase. The reaction is preferably carried out in an inert siliceous or aluminous substrate at temperatures ranging from 60.degree. C to 150.degree. C. Lithium chloride has proven to be useful as a catalyst, but by no means essential.
Claims7
The method of preparing 4-chloro-2-methyl- crotonaldehyde, which comprises subjecting 1:
- 2-epoxy-2-methyl-3-butene to chlorination reaction with a chlorinating agent consisting of cupric chloride in the liquid phase or tert-butyl hypochlorite in the vapor phase on a substrate selected from the group consisting of silica and alumina and combinations thereof.
Dependencies are inferred from the claim text.