Preparation of p-chlorobenzalchloride
The chlorination is best carried out in a three-necked flask with a mercury immersion lamp, a gas inlet tube, and a highly efficient reflux condenser.
If no mercury immersion lamp is available, the mixture can be irradiated from outside with a 500-watt photolamp or the chlorination can be carried out in direct sunlight. However, the reaction then takes place somewhat more slowly and the yields are generally lower. The gaseous chlorine is dried in a wash-bottle with concentrated sulfuric acid. An empty wash-bottle must be connected on either side of this washing bottle as safety vessels. The 4-chlorotoluene is heated to the boiling point, using a heating bath, and a vigorous stream of gaseous chlorine is passed in. During the chlorination reaction no gaseous chlorine should pass through the condenser (color). Chlorination is continued until the calculated increase in weight has been obtained. The reaction product is fractionated through a 20-cm Vigreux column in vacuum after the addition of small amount of sodium hydrogen carbonate. In order to obtain pure product, the main fraction first obtained is fractionated again, and fractions are collected within narrower limits. The yield is 85%, b.p. 129°C/22 mm.
Organicum. Practical Handbook of Organic Chemistry, by Heinz Becker, Werner Berger and Günter Domschke, Addison-Wesley Pub. Co, 168-169, (1973)
1-chloro-4-(dichloromethyl)benzene, 4-chlorobenzal chloride
p-Chlorobenzalchloride, 4-Chlorobenzal chloride, 13940-94-8, 4-Chlorobenzalchloride, p-Chlorobenzal chloride, 1-chloro-4-(dichloromethyl)benzene, 4-Chloro-1-(dichloromethyl)benzene, 4-Chlorobenzylidene chloride, Benzene, 1-chloro-4-(dichloromethyl)-, alpha,alpha,p-Trichlorotoluene, Alpha,alpha,4-trichlorotoluene, Toluene, alpha,alpha’,p-trichloro-, EINECS 237-721-7, BRN 0907445, AC1L36SS, 4,alpha,alpha-Trichlorotoluene, SCHEMBL7562082, Jsp002359, CTK4C1794, ZINC2584544, SBB070760, 1-chloro-4-(dichloro-methyl)-benzene, AKOS015917471, Benzene,1-chloro-4-(dichloromethyl)-, OR048783, OR145441, LS-154206, FT-0656610, 3-05-00-00699 (Beilstein Handbook Reference), S01-0548, W-108216
p-(Dichloromethyl)benzyl chloride, CID84110