GB629184A - Improvements in or relating to a process for the production of alkali metal alkoxides - Google Patents

Abstract

Sodium alkoxide is obtained as a freely-flowing powder by reacting, with agitation, an aliphatic alcohol containing not more than four carbon atoms with molten sodium at a temperature not below the critical temperature necessary for the presence of the solid alcoholate of the alkoxide and in an inert atmosphere, the alcohol being added at a rate sufficient to prevent charring of the product but insufficient to wet the reaction mixture and in sufficient stoichiometric excess to ensure that all the metal enters into combination, and heating the product until alcohol ceases to distil over. The reaction sets in more rapidly, especially in the preparation of sodium methoxide, when the metal is dispersed, preferably in a mass of the reaction product. An inert atmosphere may be provided by nitrogen or hydrogen. Sodium is charged into a jacketted reactor under an atmosphere of nitrogen, the temperature is adjusted and alcohol is run in until the reaction is shown to be complete by the cessation of hydrogen evolution and rapid distillation of alcohol. The residual alcohol is removed by heating in an inert atmosphere at or above the temperature at which the alcoholate decomposes to give the alkoxide. The process may be modified for continuous operation by feeding sodium and alcohol separately into one end of a heated horizontal tube divided into two sections and fitted with a longitudinal stirrer. The reaction takes place in the first section and removal of excess alcohol in the second. The excess alcohol may be fed back to the reaction zone. In examples the preparation of sodium methoxide, ethoxide and n-propoxide by the batch process is described. Triethanolamine, tested as a stabilizer for sodium propoxide did not produce an appreciable effect.