The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

Continuous process for co-production of acetic acid and acetic anhydride by contacting carbon monoxide with a liquid reaction composition containing methyl acetate, dimethyl ether or a mixture thereof, a Group VIII metal catalyst, methyl iodide, acetic acid, acetic anhydride, and water in a concentration of 0.1 wt % or less, withdrawing liquid reaction composition from the reaction zone, introducing at least a portion thereof into a flash separation zone, and removing from the flash separation zone a vapor fraction containing acetic anhydride, acetic acid and methyl iodide and a liquid fraction containing acetic anhydride, and Group VIII metal catalyst. The liquid reaction composition and the withdrawn liquid reaction composition introduced into the flash separation zone contains a Group IA and/or Group IIA metal salt and the molar ratio of acetic acid to acetic anhydride in the vapor fraction removed from the flash separation zone is greater than or equal to 1.

Continuous process for co-production of acetic acid and acetic anhydride by contacting carbon monoxide with a liquid reaction composition containing methyl acetate, dimethyl ether or a mixture thereof, a Group VIII metal catalyst, methyl iodide, acetic acid, acetic anhydride, and water in a concentration of 0.1 wt % or less, withdrawing liquid reaction composition from the reaction zone, introducing at least a portion thereof into a flash separation zone, and removing from the flash separation zone a vapor fraction containing acetic anhydride, acetic acid and methyl iodide and a liquid fraction containing acetic anhydride, and Group VIII metal catalyst. The liquid reaction composition and the withdrawn liquid reaction composition introduced into the flash separation zone contains a Group IA and/or Group IIA metal salt and the molar ratio of acetic acid to acetic anhydride in the vapor fraction removed from the flash separation zone is greater than or equal to 1.

A fragrance mixture and its applications, in particular perfume oils, cosmetic agents, application agents or washing and cleaning agents, containing a sensory effective amount of (i) (E)-2-methyl-but-2-endicarboxylic acid diethyl ester, (ii) (Z)-2-methyl-but-2-endicarboxylic acid diethyl ester or (iii) 2-methylenebutanedicarboxylic acid diethyl ester and mixtures thereof and analogous esters derived from these compounds and mixtures.

A fragrance mixture and its applications, in particular perfume oils, cosmetic agents, application agents or washing and cleaning agents, containing a sensory effective amount of (i) (E)-2-methyl-but-2-endicarboxylic acid diethyl ester, (ii) (Z)-2-methyl-but-2-endicarboxylic acid diethyl ester or (iii) 2-methylenebutanedicarboxylic acid diethyl ester and mixtures thereof and analogous esters derived from these compounds and mixtures.

A fragrance mixture and its applications, in particular perfume oils, cosmetic agents, application agents or washing and cleaning agents, containing a sensory effective amount of (i) (E)-2-methyl-but-2-endicarboxylic acid diethyl ester, (ii) (Z)-2-methyl-but-2-endicarboxylic acid diethyl ester or (iii) 2-methylenebutanedicarboxylic acid diethyl ester and mixtures thereof and analogous esters derived from these compounds and mixtures.

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.