Dover Chemical Corporation

Carroll W Larke

Donald R Stevenson

Satyan Kodali

John C Debevec

Daniel L Clark

Charles N Slater

A method is disclosed for the production of pentaerythritol diphosphites of high spiro isomer content. The pentaerythritol diphosphites are produced via sequential transesterification of pentaerythritol with a monophosphite followed by a substituted phenol or other alcohol, wherein the transesterification reactions are carried out under controlled conditions of temperature and pressure. The unique reaction conditions result in intermediate and final pentaerythritol diphosphites of high spiro isomer content and high total yield of the diphosphites.

Process for manufacture of pentaerythritol diphosphites

A solid phosphite composite, having at least a portion in amorphous form, which includes at least one, preferably two or more phosphite antioxidants or alternatively at least one phosphite and at least one other polymer additive. The phosphites, at least one of which can initially be a liquid, are generally uniformly distributed since they are melt blended. A desired class of phosphites are the bis(arylalkylphenyl)pentaerythritol diphosphites, at least a portion of which is in amorphous form.

Solid melt blended phosphite composites

An improved process for the preparation of tris(nonylphenyl) phosphite is described which includes the steps of combining at least a 4 weight percent excess of nonylphenol (preferably 8 weight percent excess) with PCl.sub.3 with agitation and heating sufficient to liberate HCl formed during the synthetic reaction as a by-product and removing the excess nonylphenol from the tris(nonylphenyl) phosphite by thin film distillation to reduce the residual chloride level to 90 ppm or less, an acid number of 0.1 or less and a nonylphenol content after stripping of 0.1 weight percent or less. The temperature of the reaction was from room temperature to 130.degree. C., and the temperature of the evaporator which removes the excess nonylphenol is from 100.degree. C. to 350.degree. C., preferably from 150.degree. C. to 250.degree. C., under a system vacuum of from 0.01 mm Hg to 5 mm Hg.

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Zoar, OH, United States of America

Carroll W Larke