Bayer Aktiengesellschaft

Lanxess Deutschland Gmbh

Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

Edwin Ritzer

Heinz U Blank

Erasmus Vogl

Johannes Kaulen

Claus Dreisbach

Herbert Diehl

Manfred Hoffmann

Alexander Klausener

Heinz Landscheidt

Robert Markert

Ralf Krahwinkel

Frank Jelitto

Robert Sollner

A method is described for the production of sorbic anhydride, in which alkali metal or alkaline earth metal salts of sorbic acid are reacted with phosgene in an inert organic solvent. In addition, use thereof as a preservative in foods, in particular drinks, is described.

Method for producing sorbic anhydride and also use thereof as a preservative in foods

Carboxylic anhydrides are highly suitable as additive for industrial materials, cosmetics, pharmaceutics and foodstuffs, in particular beverages, for protecting them against attack and/or destruction by microorganisms.

Preservatives based on carboxylic anhydrides

Dibenzyl carbonates are prepared by reacting a dialkyl carbonate with a benzyl alcohol in the presence of a basic catalyst and removing the highly volatile components and the catalyst from the reaction mixture. This process permits the preparation of benzyl carbonates in a simple manner, in good yields and without any particular technical safety arrangements.

Method for the production of dibenzyl carbonates

The present invention relates to a process for preparing optionally substituted benzyl carbazates of formula (I) ##STR1## wherein each R.sup.1 independently represents C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, di(C.sub.1 -C.sub.4 -alkyl)amino, nitro, halogen, hydroxyl, the group X-R.sup.3, wherein X represents O or S and R.sup.3 represents straight-chain or branched C.sub.1 -C.sub.4 -alkyl, the group COOR.sup.4, wherein R.sup.4 represents C.sub.1 -C.sub.4 -alkyl, the group NR.sup.5 R.sup.6, wherein R.sup.5 and R.sup.6 independently represent C.sub.1 -C.sub.4 -alkyl, or a C.sub.3 -C.sub.6 -cycloalkyl group that is optionally substituted by straight-chain or branched C.sub.1 -C.sub.4 -alkyl groups, and

Process for preparing benzyl carbazates

Alkyl carbazates of the formula R.sup.1 --O--CO--NH--NH.sub.2 (I) are prepared in an advantageous manner by reacting an alkyl carbazate of the formula R.sup.2 --O--CO--NH--NH.sub.2 (II) with alcohols of the formula R.sup.1 --OH (III) in the presence of a catalyst, where the symbols used in the formulae are as defined in the description.

Process for the preparation of carbazates

Substituted 3,5-dichloro-2,4-difluoro-benzenes of the formula ##STR1## in which R represents nitro, amino (including the corresponding ammonium salts) or isocyanato, which can be prepared from 2,3,4,5-tetrachloro-nitrobenzene by means of the reaction, carried out initially, with alkali metal fluorides at elevated temperature in a polar, aprotic solvent, starting from a crude 2,3,4,5-tetrachloro-nitrobenzene containing 2,3,5,6-tetrachloro-nitrobenzene and/or 2,3,4,6-tetrachloro-nitrobenzene, and substituted 3,5-dichloro-2,4-difluoro-benzene being isolated from the reaction mixture at the nitro stage or, after reduction of the nitro group, at the amino stage or, after reduction and phosgenation of the amino group, at the isocyanate stage.

Process for the preparation of substituted

Cyclopropanecarboxamide can be prepared by reaction of a cyclopropanecarboxylic ester with NH.sub.3, in which the ester alcohol has 4-8 C atoms and can be straight-chain or branched and which process is carried out in the presence of catalytic amounts of an alkali metal alcoholate of a monohydric C.sub.1-C.sub.8 alcohol at 60.degree.-200.degree. C. in the absence of a hydrocarbon solvent.

Process for the preparation of cyclopropanecarboxamide

The present process for the preparation of cyclopropylamine by the so-called Hofmann degradation of cyclopropanecarboxamide is characterized in that the cyclopropanecarboxamide is employed in the form of a solution. The new process can be carried out at 5.degree.-35.degree. C. The cyclopropylamine is obtained after introducing the reaction mixture into a concentrated alkali metal hydroxide solution.

Process for the preparation of cyclopropylamine

Substituted fluorobenzenes which are produced in aprotic, polar solvents or in mixtures which contain such solvents can be obtained by extracting the substituted fluorobenzenes from the solvents or solvent mixtures with aliphatic extracting agents and then seaprating the extracting agents from the substituted fluorobenzenes.

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Leverkusen, Germany

Edwin Ritzer