GB848486A - Production of perchloryl fluoride - Google Patents

Abstract

Perchloryl fluoride is prepared by interacting perchloric acid or a perchlorate with fluosulphonic acid at a temperature between 40 DEG C. and the b.p. of the reaction mixture, and withdrawing the gas evolved as the desired product before substantial quantities of by-product gas are formed. Sodium, potassium, lithium, calcium, and magnesium perchlorates are specified. The molar ratio of fluosulphonic acid to perchloric acid or perchlorate is preferably at least 6 to 1, and may be, for example, 10 to 1. The reaction mixture may be passed down a steam-heated vertical packed tower at a temperature of 100-135 DEG C. for a retention time of 1-10 minutes. At a reaction temperature of 40 DEG C. the retention time may be 30 minutes. The product gas may be scrubbed simultaneously or in succession with a neutralising agent and a reducing agent in aqueous solution, e.g. with a solution containing 10-25% of sodium hydroxide and 10-25% of sodium thiosulphate. The gas may then be successively scrubbed with a 5-10% aqueous sodium hydroxide solution and water, dried by passage over activated alumina or solid sodium hydroxide, and liquefied by compression. Reaction may be continued in the residual liquid at a temperature between 40 DEG C. and the b.p. thereof until evolution of by-product gas, which comprises chlorine, oxygen, and sulphur dioxide, has ceased. The by-product gas may be vented after scrubbing with aqueous caustic soda solution. The residual fluosulphonic acid may then be distilled off and recycled to the process.