Hoechst Aktiengesellschaft

Clariant Corporation

Georg Folz

Theodor Papenfuhs

Ralf Pfirmann

Gilbert Billeb

Process for the preparation of 4-alkylsulfonyl-1-alkyl-2-chlorobenzenes and similar compounds

Process for preparing 4-alkyl-3-chloroalkylsulfonylbenzenes of the formula (1) ##STR1## in which R.sup.1 and R.sup.2 are identical or different and are each (C.sub.1 -C.sub.4)-alkyl.

4-alkyl-3-chlorobenzenesulfinic acids,

A process for the continuous production of aromatic aldehydes of the formula (1) ##STR1## in which Ar is an aryl radical, R.sup.1, R.sup.2 and R.sup.3 independently of one another are hydrogen, fluorine, chlorine or bromine atoms, in which dichloromethyl-substituted aromatics of the formula (2) ##STR2## in which Ar, R.sup.1, R.sup.2, R.sup.3 have the above meanings, are continuously hydrolyzed with an aqueous solution of one or more catalysts of the formula (3)

Process for the continuous production of aromatic aldehydes

Process for the preparation of 2,4-dichlorofluorobenzene in high yield and purity without intermediate separation of the isomers formed,(1) by nitrating 1 mol of fluorobenzene to give nitrofluorobenzene using a mixture comprising 35 to 65 parts by weight of 50 to 90% strength sulfuric acid and 35 to 65 parts by weight of a nitrating acid comprising 35 to 55 parts by weight of 95 to 98% strength sulfuric acid and 45 to 65 parts by weight of 96 to 98% strength nitric acid, with the proviso that 0.8 to 2.0 equivalents of the nitrating agent NO.sub.2.sup.+ are used per mol of fluorobenzene, at 20.degree. to 90.degree. C., (2) allowing 25 g to 150 g of chlorine, in the presence of a ring chlorinating catalyst, to act on each 100 g of the crude nitrofluorobenzene mixture obtained, at 20.degree. to 100.degree. C., and (3) allowing about 18 g to about 203 g of chlorine or equivalent amounts of a chlorine releasing agent to act on each 100 g of the crude chlorofluoronitrobenzene mixture obtained, after removal of the ring chlorinating catalyst, at 110.degree. to 220.degree. C., and isolating the 2,4-dichlorofluorobenzene.

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Frankfurt am Main, Germany

Georg Folz