Bayer Aktiengesellschaft

Josef Bremen

Dieter Arlt

Bernhard Wehling

Adolf Winkler

Alexander Klausener

Florin Seng

Carl-Wolfgang Schellhammer

G&uuml;nter Rauchschwalbe

Ralf-Ingo Schenkel

Andreas Groschl

The invention relates to a process for the alkylation of 3,4-dihydroxythiophene-2,5-dicarboxylic esters or their alkali metal or alkaline earth metal salts with alkylating agents in a polar diluent in the presence of quaternary onium salts.

Process for the alkylation of 3,4-dihydroxythiophene-2,5-dicarboxylic esters

A process as been found for the removal of water from reaction mixtures of acids or acid anhydrides or of aqueous alkali metal hydroxide solutions with alcohols using vapor permeation/pervaporation at the boiling point of the reaction mixture, which includes initially introducing the lowest-boiling educt in less than the stoichiometric amount, based on the other particular educt, together with this other educt, heating the reaction mixture to the boiling point and freeing the vapor mixture, which is formed from the boiling reaction mixture and includes chiefly water and the lowest-boiling component, from water on a membrane, recycling the vapor mixture which has been freed from water into the reaction mixture and topping up the reaction mixture with the lowest-boiling educt in the course of the reaction.

Removal of water from reaction mixtures

.beta.-Aminoethyl ketones are obtained in a low-polluting manner by Mannich condensation of an aryl ketone having an acidic H with an aldehyde and ammonia or an amine by carrying out the reaction in organic nitriles in the presence of a sulphonic acid or in gycol either in the presence of a sulphonic acid or sulphuric acid.

Process for the preparation of .beta.-aminoethyl ketones

Compounds of the formula ##STR1## in which R.sub.1 denotes aryl, alkyl, aralkyl, styryl or alkoxy,

Benzofuranyl-benzimidazoles

Optical brighteners of the formula ##STR1## wherein the radicals R.sub.1 to R.sub.9 are substituents customary in brightener chemistry,

Process for the preparation of benzimidazolylbenzofuranes

Storable, autocrosslinkable polymers containing N-alkoxymethyl groups are obtained by reacting 5-alkoxymethyl-1,3,4-dioxazol-2-ones with a polymer having an average molecular weight above 600 and an average of more than one Zerewitinoff-active hydrogen atom in the molecule in the presence of a catalytic quantity of at least an alkali metal salt. The new catalysts allow to carry out the reaction at a temperature in the range from 50.degree. to 110.degree. C and guarantee a complete reaction of the reactants into uncrosslinked but autocrosslinkable light-stable end products.

Process for the production of autocrosslinkable polymers containing

The instant invention is directed to a process for the preparation of isopropenyl isocyanate comprising pyrolyzing 5-isopropenyl-1,3,4-dioxazolinone-2 in the gaseous phase, at a temperature above 200.degree.C.

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Leverkusen, Germany

Josef Bremen