Bayer Aktiengesellschaft

Klaus-Friedrich Lehment

Roderich Raue

Adolf Staffe

Albrecht Marhold

Reinhard Lantzsch

Gerhard Wolfrum

Herbert Hugl

Hans-Peter Kuhlthau

Harald Gleinig

Wilhelm Backhaus

Arthur H Schmidt

Methine dyestuffs of the formula ##STR1## are prepared by subjecting a compound ##STR2## to a condensation reaction with a compound

Process for the preparation of cationic methine dyestuffs

Process for the preparation of styryl dyestuffs of the formula ##STR1## in which R.sub.1 and R.sub.2 denote hydrogen, alkyl, alkoxy or halogen and

Process for the preparation of styryl dyestuffs

The preparation of hydrazone dyestuffs of the formula ##STR1## wherein R.sup.13 and R.sup.14 independently of one another represent hydrogen, C.sub.1 -- to C.sub.4 --alkyl, C.sub.1-- to C.sub.4-- alkoxy or halogen, in particular chlorine or bromine, and

Process for the preparation of cationic dyestuffs

An improvement in a process for the preparation of dichlorophene by reacting p-chlorophenol with formaldehyde in the presence of sulfuric acid. The improvement lies in contacting p-chlorophenol with the stoichiometric excess of formaldehyde in aqueous sulfuric acid by introducing into a sulfuric acid reaction medium 1 to 6% by weight of the total amount of p-chlorophenol to be reacted and thereafter adding the formaldehyde and additional p-chlorophenol to the reaction mixture in an amount such that at the end of the addition of the p-chlorophenol only 85 to 98% by weight of the total amount of formaldehyde has been added. The balance of the formaldehyde is then introduced into the reaction mixture.

Preparation of dichlorophene

Sulfonic acid fluorides are prepared by reacting sulfonic acid halides with inorganic fluorides in an organic-aqueous phase. The reaction is carried out in the presence of catalytic amounts of an amine or an onium salt.

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Odenthal, Germany

Klaus-Friedrich Lehment