Patent GB-631669-A (GB)
Title: Improvements in the production of organic chlorine compounds
IPC: C07C17/26
Filed: 1946-08-27
Abstract: Organic chlorine compounds are produced by condensing a halogenated aliphatic aldehyde containing from 2 to 12 carbon atoms with chlorbenzene or chlortoluene in the presence of fluosulphonic acid. The mol. ratio of fluosulphonic acid to aldehyde, e.g. with chloral, is less than three to one, effectively less than two to one.  The fluosulphonic acid may be mixed with free sulphuric acid or free hydrogen fluoride in which case the proportion of p,p to o isomers obtained will be influenced, hydrolysis of the condensing agent may be suppressed and sulphonation within the reaction mixture prevented. It is preferred that only about 50 per cent of the theoretical quantity of aldehyde be reacted so that the reaction mixture remains liquid and the use of high temperatures is thereby avoided. Temperatures instanced range from about - 30 DEG  C. to 165 DEG  C. and are preferably between 0 DEG  and 60 DEG  C.  At high temperatures superatmospheric pressure is used.  The spent fluosulphonic acid may be used to dehydrate fresh batches of aldehyde hydrates such as chloral and butyl chloral hydrates.  The presence of copper facilitates the production of p-isomers, particularly when producing p,p - dichlor - diphenyl - trichlorethane.  In examples, in which fluosulphonic acid is used as condensing agent, (1) chloral is reacted with chlorbenzene in a copper kettle at 30-50 DEG  C. for about 1 to 2 hours to yield p,p-dichlordiphenyl-trichlorethane; (2) chloral is reacted with o-chlortoluene with conditions similar to (1) to produce 4 : 41-dichloro-3 : 31-dimethyl-1 : 1 - diphenyl - 2 : 2 : 2 - trichlorethane; (3) chloral is reacted with 3,4-dichlortoluene, as in (1) and (2), to produce 2 : 21-dimethyl-4 : 5-41 : 51 - tetra - chloro - 1 : 1 - diphenyl - 2 : 2 : - trichlorethane; (4) butyl chloral is reacted with chlorbenzene with conditions similar to those of (1) to produce 4 : 41-dichloro-1 : 1-diphenyl-2 : 2 : 3-trichlorbutane, and similarly in (5) dichloro-acetaldehyde is reacted with chlorbenzene to produce 4 : 41-dichloro-1 : 1-diphenyl-2 : 2-dichlorethane.  In the Specification as open to inspection under Sect. 91, it is stated that an aliphatic organic compound, containing not less than 2 or more than 12 carbon atoms and at least one carbonyl group and substituted with one or more halogen or thiocyano radicles is condensed with two or more molecules of benzene, naphthalene or their derivatives containing as nuclear substituents halogen, nitro, sulpho, amino, thiocyano, alkoxy and alkyl groups of more than two carbon atoms, and methyl or methoxy groups, when in conjunction with halogen, nitro, sulpho, amino and thiocyano groups in the presence of halogensulphonic acid, fluosulphonic acid being preferred, to give products similar to those above instanced.  The following compounds are specified reactants: benzene, chlorbenzene, dichlorbenzene, mono and dichlor toluenes, chlor-xylenes, bromo- and fluorobenzenes, nitro-benzene, naphthalenes, biphenyl, chlor-biphenyls, benzene sulphonyl fluoride, chloral, butyl chloral, thiocyano-acetaldehyde, thiocyano-ethyl-hexaldehyde, dichloro- or dithiocyano-ethyl-hexaldehyde, dichloro- and pentachloro-acetone, 3,4-dithiocyano-4-methyl-2-pentanone and 4-thiocyano-4-methyl-pentanone.  Heavy metal salts and reaction temperature are stated to influence the orientation of the isomers obtained.  This subject-matter does not appear in the Specification as accepted.