The Dow Chemical Company

Masao Yoshimine

Lorraine M Kroposki

Harold H Freedman

Stanley D McGregor

Che-I Kao

Sanford A Siegel

Erwin H Kobel, Deceased

A molten substituted phenol and an aqueous caustic solution are reacted at temperatures from 170.degree. C. to 190.degree. C. under superatmospheric pressure to form an aqueous solution of an alkali metal phenate. By employing a rapid drying process such as flashing the water vapor from the reactor to cool the mixture, alkali metal phenate solids are produced with low levels of toxic by-products.

Production of alkali metal phenates

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

The decomposition of pentachlorophenol during distillation to remove impurities is markedly reduced by incorporating into the distilling molten pentachlorophenol a hydroxyl or polyhydroxyl containing organic compound having a boiling point above about 100.degree. C. in the presence or absence of water.

Method for purifying pentachlorophenol

Mixtures of (1) a quaternary ammonium salt(s) and (2) a diazole are novel catalysts in the process of reacting an alkali metal phenate, pyridinate or pyrimidinate with an O,O-dialkyl phosphorochloridothioate or O-alkyl phenylphosphonochloridothioate to produce the corresponding title compounds. The process is conducted under alkaline conditions in a liquid reaction medium. As an example, O,O-diethyl O-(3,5,6-trichloro-2-pyridyl)phosphorothioate is prepared in excellent yields and purity by reacting sodium 3,5,6-trichloro-2-pyridinate with O,O-diethyl phosphorochloridothioate in a stirred methylene chloride-water reaction medium in the presence of a catalytic amount of benzyltriethylammonium chloride and 1-methylimidazole.

Mixtures of (1) a quaternary ammonium salt(s) and (2) 1,4-diazabicyclo[2.2.2]octane are novel catalysts in the process of reacting an alkali metal phenate, pyridinate or pyrimidinate with an O,O-dialkyl phosphorochloridothioate or O-alkyl phenylphosphonochloridothioate to produce the corresponding phosphorothioates and phenylphosphonothioates. The process is conducted under alkaline conditions in a liquid reaction medium. As an example, O,O-diethyl O-(3,5,6-trichloro-2-pyridyl)phosphorothioate is prepared in excellent yields and purity by reacting sodium 3,5,6-trichloropyridinate with O,O-diethyl phosphorochloridothioate in a stirred methylene chloride-water reaction medium in the presence of a catalytic amount of benzyltriethylammonium chloride and 1,4-diazabicyclo[2.2.2]octane.

Mixtures of (1) a quaternary ammonium salt(s) and (2) 1,4-diazabicyclo[2.2.2]octane are novel catalysts in the process of reacting an alkali metal phenate, pyridinate or pyrimidiate with an O,O-dialkyl phosphorochloridothioate or O-alkyl phenylphosphonochloridothioate to produce the corresponding phosphorothioates and phenylphosphonothioates. The process is conducted under alkaline conditions in a liquid reaction medium. As an example, O,O-diethyl 0-(3,5,6-trichloro-2-pyridyl)phosphorothioate is prepared in excellent yields and purity by reacting sodium 3,5,6-trichloropyridinate with O,O-diethyl phosphorochloridothioate in a stirred methylene chloride-water reaction medium in the presence of a catalytic amount of benzyltriethylammonium chloride and 1,4-diazabicyclo[2.2.2]octane.

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Midland, MI, United States of America

Masao Yoshimine