GB1181873A - A process for the production of Halo-Alkenes - Google Patents

Abstract

1,181,873. Production of halo-alkenes. SOC. NATIONALE DES PETROLES D'AQUITAINE. 15 May, 1967 [18 May, 1966; 3 May, 1967], No. 22477/67. Heading C2C. Halo-alkenes, in which the molecule contains at least two halogen atoms, are obtained by treating with a halogen, an alkenyl thioester which satisfies at least one of the following two conditions: (a) the end carbon atom of the alkenyl chain, which is double-bonded, is substituted with one or two elements or groups which are donors of electrons; (b) the second carbon atom of the alkenyl chain, to which the said double bond extends, carries a group which is an attracter of electrons. The electrondonating element or group in the starting material may be halogen or an alkyl radical, or an aryl radical substituted in the ortho and/or para positions with a hydroxy, methoxy, carboxy, halo, phenyl, alkyl, alkylcarboxy or amido group, the electron-attracting group in the starting material may be an aryl group substituted in the meta-position with an electronegative group, e.g. nitro, cyano, sulphonic, acyl, carboxy or amido group, and the thioacid from which the thioester starting material is derived may be an aliphatic, alicyclic or aromatic thioacid. The reaction may be effected in an inert solvent at a temperature of- 30‹ C. to 100‹ C. and, when a mixture of tetrachloroproprene isomers is the product of the reaction they may be isomerized, e.g. in the presence of a Friedel-Crafts catalyst, to yield 1,1,3,3-tetrachloroproprene. In specific examples the products obtained are 1,3,3- and 1,1,3-trichloropropene, 1,2,3,3-, 1,3,3,3- and 1,1,3,3-tetrachloropropene, and 1,2,3,3,3-pentachloropropene, some pentachloropropane also being formed.