The Dow Chemical Company

Dowelanco

1 . . . Limited

Thomas J Dietsche

Jon A Orvik

Paula L Humphreys

Alexander P Fung

Jim Love

Marc E Halpern

M Moklesur Rahman

Michael A DesJardin

J Brian Barron

Jonathan A Okorley

Richard K Helling

Charles B Grant

Philip D Grover

Mark L Garibaldi

James L Bixby

Trevor E Gray

Chloro and bromophenols and N-acylanilines are fluorinated in an ortho or para position with an N-fluoropyridinium salt to obtain fluorohalophenols and N-acylfluorohaloanilines, which can be further converted to fluorophenols and N-acylfluoroanilines by reduction. Thus, o-fluorophenol is obtained by fluorination of p-bromophenol with 2-chloro-6-(trichloromethyl)pyridinium fluoroborate and reduction of the product obtained with sodium formate and a palladium catalyst. N-Fluoropyridinium salts having trichloromethyl substituents are disclosed.

Preparation of fluorohalophenols and N-acylfluorohaloanilines

Chloro and bromophenols and N-acylanilines are fluorinated in an ortho or para position with an N-fluoropyridinium salt to obtain fluorohalophenols and N-acylfluorohaloanilines, which can be further converted to fluorophenols and N-acylfluoroanilines by reduction. Thus, o-fluorophenol is obtained by fluorination of p-bromophenol with 2-chloro-6-(trichloromethyl)-pyridinium fluoroborate and reduction of the product obtained with sodium formate and a palladium catalyst. N-fluoropyridinium salts having trichloromethyl substituents are disclosed.

Preparation of fluorohalophenols and N-acyfluorohaloanilines

2-Hydrocarbyl-3,6-dichloropyridines are prepared from dichloromethyl hydrocarbyl ketones and acrylonitrile in a two-step process involving an addition reaction under basic conditions to form intermediate 1,1-dichloro-3-cyanopropyl hydrocarbyl ketones and a subsequent cyclization reaction in the presence of hydrogen chloride. Thus, 3,6-dichloro-2-methylpyridine is prepared from 1,1-dichloro-2-propanone and acrylonitrile by the formation and further reaction of 4,4-dichloro-5-oxo-hexanenitrile. The intermediates and products are novel compounds useful in the preparation of herbicides and nitrification inhibitors.

2-hydrocarbyl-3,6-dichloropyridines and their preparation

2-hydrocarbyl-3,6-dichloropyridine compounds

Symmetrical tetrachloropyridine is prepared by contacting chlorinated .beta.-(trichloromethyl)pyridines with chlorine in a liquid phase reaction in the presence of from 0.1 to 1.0 mole % of a catalyst.

Preparation of symmetrical tetrachloropyridine from chlorinated

The relative amounts of 5,6-dichloro-2-(trichloromethyl)pyridine and 3,6-dichloro-2-(trichloromethyl)pyridine obtained in the chlorination of 2-chloro-6-(trichloromethyl)pyridine in the liquid phase at temperatures of about 160.degree. C. to about 220.degree. C. and in the presence of a metal halide catalyst, such as ferric chloride, are controlled by regulating the amount of hydrogen chloride present in the system, adding hydrogen chloride to obtain a mixture enriched in 5,6-dichloro-2-(trichloromethyl)pyridine or removing hydrogen chloride, usually by passing excess chlorine or an inert gas through the system, to obtain a mixture enriched in 3,6-dichloro-2-(trichloromethyl)pyridine.

Control of isomer distribution in a chlorination process

Novel methods for preparing 2-cyano-6-chloropyridines are disclosed. The compounds are useful as intermediates in preparing other intermediates or as intermediates directly used in making pesticides, especially herbicides.

Preparation of 2-cyano-6-chloropyridine compounds

Trichloro- and tetrachloro(trichloromethyl)pyridines contaminated with hexachlorobenzene are converted to useful products containing acceptably low levels of hexachlorobenzene by chlorination under conditions of chlorinolysis to tetrachloro- and pentachloropyridine and then removing the hexachlorobenzene by distillation. For example, 2,3,6-trichloro-5-(trichloromethyl)pyridine contaminated with hexachlorobenzene is converted to 2,3,5,6-tetrachloropyridine containing less than 50 ppm hexachlorobenzene.

Polychloropyridines from polychloropicolines contaminated with

Novel 2,3-bis((poly)chloromethyl)pyridines and 3,6-dichloro--2-(polychloromethyl)pyridines were obtained by vapor phase chlorination of 2,3-lutidine. Chlorination at about 350.degree. C. using a 14.4 sec. residence time and a chlorine to 2,3-lutidine mole ratio of about 6.8, for example, produced 2-(chloromethyl)-3-(dichloromethyl) pyridine, 3-(chloromethyl)-2-(dichloromethyl)pyridine, 2,3-bis(dichloromethyl)pyridine, 6-chloro-2,3-bis(dichloromethyl)pyridine, 3-(dichloromethyl)-2-(trichloromethyl)pyridine, 6-chloro-3-(dichloromethyl-2-(trichloromethyl)pyridine, 6-chloro-2-(dichloromethyl)-3-(trichloromethyl)pyridine, and 3,6-dichloro-2-(trichloromethyl)pyridine. The compounds are useful as starting materials for herbicides and pharmaceutical agents.

2,3-bis-(poly)(chloromethyl)pyridines

Polychloropyridines containing chlorine substituents in the 2, 3, and 6 positions and, optionally, in the 4 and 5 positions, are prepared from polychloro-2,3-lutidines containing at least one chlorine substituent in each methyl group and, optionally, a chlorine substituent in the 6 position by liquid phase chlorination. Lewis acid metal halide catalysts are, optionally, employed. 2,3,5,6-Tetrachloropyridine is, accordingly, prepared by chlorination at about 200.degree. to about 260.degree. C. in the presence of ferric chloride catalyst of a mixture of polychloro-2,3-lutidines obtained by the vapor phase chlorination of 2,3-lutidine.

Polychloropyridine production from polychloro-2,3-lutidines

The selective chlorination of 2-chloro-5-(trichloromethyl)pyridine in the 3-position is achieved by reacting 2-chloro-5-(trichloromethyl)pyridine in the liquid phase with an effective amount of Cl.sub.2 at an elevated pressure and elevated temperature in the absence of an added catalyst.

Method of selectively chlorinating 2-chloro-5-(trichloromethyl) pyridine

A method is disclosed for preparing a chlorinated .beta.-methylpyridine by chlorinating a .beta.-methylpyridine compound with PCl.sub.5 in the presence of phenylphosphonic dichloride.

Chlorination of .beta.-methylpyridine compounds

Symmetrical tetrachloropyridine, pentachloropyridine and poly-chloro derivatives of 2-chloro-6-(trichloromethyl)pyridine are prepared by reacting a chloro-substituted (trichloromethyl)pyridine in the liquid state with chlorine at temperatures of from at least about 160.degree. C. and in the presence of an amount of a catalyst effective to catalyze the reaction.

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Berkeley, CA, United States of America

Thomas J Dietsche