Zeneca Limited

Syngenta Corporation

Kambiz Javdani

Gilbert Rodriguez

James Peter Muxworthy

Louie A Nady

Ping H Sih

James Peter Syngenta Limited Muxworthy

A method for removing impurities from 2-nitro-4-methylsulfonylbenzoic acid which comprises at least two of the following steps, in any order, (a) dissolving 2-nitro-4-methylsulfonylbenzoic acid in water at a pH of about 2 to 10, followed by filtration; (b) contacting an aqueous solution of 2-nitro-4-methylsulfonylbenizoic acid with activated carbon at a pH of about 2 to 10; (c) treating an aqueous solution of 2-nitro-4-methylsulfonylbenzoic acid with sufficient base to hydrolyze undesired nitro and dinitro substituted impurities; followed by maintaining the resulting aqueous solution comprising 2-nitro-4-methylsulfonylbenzoic acid at a temperature of up to about 95&#xb0; C., and adjusting the pH of said solution to about a pH which is sufficient to effect crystallization of 2-nitro-4-methylsulfonylbenzoic acid upon cooling.

Purification of 2-nitro-4-methylsulphonylbenzoic acid

Aromatic azomethines are produced by continuous reaction of an aniline with a formaldehyde source, with continuous evaporation to remove residual water of reaction. The azomethine product may be further reacted, either continuously or in batch process, with a haloacetylating agent, and, additionally, with an aliphatic alcohol.

Process for the production of azomethines and alpha-haloacetanilides

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Kambiz Javdani