The Dow Chemical Company

Stanley D McGregor

Harold H Freedman

Masao Yoshimine

Lorraine M Kroposki

Herman O Senkbeil

Chun S Wang

Terry J Nestrick

A process for the dehydrohalogenation of a (polyhaloalkyl)benzene containing a benzylic halogen such as 1,3-dichloro-5-(2,4,4,4-tetrachlorobutyl)-benzene by contacting the (polyhaloalkyl)benzene with a Lewis acid such as AlCl.sub.3 deposited on an inert support such as silica gel or alumina under conditions sufficient to catalyze said dehydrohalogenation to form a (polyhaloalkenyl)benzene such as 3,5-dichloro-.alpha.-(2,2,2-trichloroethyl)styrene.

Dehydrohalogenation of (polyhaloalkyl) benzenes with support Lewis acid

Quaternary ammonium salts and sterically unhindered, nucleophilic, tertiary amines are novel cocatalysts which are used in the process of reacting an alkali metal phenate, pyridinate or pyrimidinate with an O,O-dialkylphosphorochloridothioate or O-alkyl phenylphosphonochloridothioate to produce the corresponding phosphorothioates and phenylphosphonothioates. The process is conducted under alkaline conditions in a liquid reaction medium.

Process for preparing phosphorothioates and phenylphosphonothioates

In the process for preparing 2,3,5-trichloropyridine, 2,3,4,5- or 2,3,5,6-tetrachloropyridine by the oxidation of the appropriate trichloro- or tetrachlorohydrazinopyridine, the improvement which comprises carrying out the oxidation with an alkaline hypochlorite in the presence of a reaction medium.

Preparation of chloro substituted pyridines

Compounds corresponding to the formula ##STR1## wherein X represents chloro, bromo, or fluoro; R represents one of cyano (-CN), carbamoyl (--CONR.sup.3 R.sup.4) or carboxy (--COOH) or the carboxylic acid salts thereof; each of R.sup.3 and R.sup.4 independently represents hydrogen or alkyl of 1 to 8 carbon atoms; M represents hydrogen or loweralkyl; R.sup.1 represents hydrogen, loweralkyl, amino or loweralkylamino of 1 to 4 carbon atoms; and R.sup.2 represents hydrogen, X, loweralkyl, amino or loweralkylamino, with the proviso that one of R.sup.1 or R.sup.2 is always amino or loweralkylamino and the other of R.sup.1 and R.sup.2 is always other than amino or loweralkylamino are prepared. These compounds are useful as herbicides and as active agents in compositions used as herbicides.

Herbicidal use of aminohalopyridyloxy acids and derivatives thereof

3,6-Dichloropicolinic acid is prepared by reacting 3,5,6-trichloro-4-hydrazino picolinic acid with from 2 to 3 moles of a basic reagent per mole of the picolinic acid reactant, acidifying the reaction mixture with a mineral acid and recovering the desired 3,6-dichloropicolinic acid product.

Preparation of 3,6-dichloropicolinic acid

A method for preparing 2,5-dihalopyrazines corresponding to the formula ##SPC1## Wherein X represents chloro, bromo or fluoro which comprises, reacting a 3,5,6-trihalo-2-hydrazinopyrazine of the formula ##SPC2## With an aqueous alkali metal hydroxide in the presence of a hydroxylic reaction medium.

Method for preparing 2,5-dihalopyrazines

3,5,6-Trichloropicolinic acid is prepared in a process which comprises

Preparation of 3,5,6-trichloropicolinic acid

A method for preparing 2,5-dihalo- and 2,5,6-trihalopyridines corresponding to the formula ##SPC1## Wherein each X independently represents chloro, fluoro or bromo and R represents hydrogen, chloro, fluoro or bromo which comprises reacting a halohydrazinopyridine of one of the formulas ##SPC2## With an excess of an aqueous alkali metal hydroxide in the presence of a reaction medium from the group consisting of loweralkanols of 1 to 4 carbon atoms and loweralkylglycols of 2 to 4 carbon atoms.

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Midland, MI, United States of America

Stanley D McGregor