Treatment of methanolic-aqueous residues from syntheses employing triphenylphosphonium salts

US4206153A · kind A · utility

Assignee

• BASF SE

Inventors

• Paul Grafen · Bad Dürkheim, DE
• Hans-Ulrich Scholz · Bad Dürkheim, DE
• Bernhard Schulz · Schwetzingen, DE

Key dates

• Filing date: Dec 15, 1978
• Grant date: Jun 3, 1980
• Expiry date: Dec 15, 1998

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C2601/16
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for treating residues which result from the Wittig synthesis of olefins and which consist principally of methanol, triphenylphosphine oxide, salts and organic by-products, by steam-stripping the volatile constituents, with partial condensation of the steam, and separating the resulting aqueous-organic mixture at 80.degree.-100.degree. C. into a saline aqueous phase and an organic phase containing principally triphenylphosphine oxide. Using this process provides a simple method of freeing, from triphenylphosphine oxide and other organic impurities, the effluent from syntheses which result in the formation of triphenylphosphine oxide, and thereby on the one hand substantially facilitates the purification of the effluent and on the other hand provides a simple method of recovering the triphenylphosphine oxide. The latter compound, which is easily purified by distillation or recrystallization, can then be used, for example, to prepare the triphenylphosphine required for Wittig syntheses or to prepare the triphenylphosphine dichloride required for the synthesis of pesticides.