PHOSPHINE AND ITS DERIVATIVES

Although phosphine [7803-51-2] was discovered over 200 years ago ia 1783 by the French chemist Gingembre, derivatives of this toxic and pyrophoric gas were not manufactured on an industrial scale until the mid- to late 1970s. Commercial production was only possible after the development of practical, economic processes for phosphine manufacture which were patented in 1961 (1) and 1962 (2). This article describes both of these processes briefly but more focus is given to the preparation of a number of novel phosphine derivatives used in a wide variety of important commercial appHcations, for example, as flame retardants (qv), flotation collectors, biocides, solvent extraction reagents, phase-transfer catalysts, and uv photoinitiators. 

Two processes have been used to manufacture gaseous phosphine on a large scale. These are commonly known as the alkaline (1) and acid processes (2). 

In the alkaline process, an aqueous solution of sodium hydroxide is allowed to react with molten, yellow phosphoms. A long-chain alcohol is used as a dispersant (3). The reaction to produce phosphine may be represented by equation 1. 

However, hydrogen is formed in two side reactions, ie, by the decomposition of some sodium hypophosphite (eq. 2) and by the direct reaction of phosphoms with sodium hydroxide (eq. 3). 

In the acid process, yellow phosphoms is converted to a mixture of yellow and red by heating to almost 300°C for several hours. The mixture is subsequently treated with steam at 280°C to produce phosphine (eq. 4). 

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