Restoration of triphenylphosphine using the “sulfur method”: two valuable chemicals from waste products

Abstract

Ph₃P is found to be inert to sodium in toluene even on heating. This phenomenon leads to the finding that in toluene Ph₃PS reacts with sodium efficiently and selectively to produce quantitative yields of highly valuable Ph₃P and anhydrous Na₂S. By applying this finding, anhydrous Na₂S can be safely and conveniently prepared using a Ph₃P-mediated reaction from sodium and sulfur. This finding also leads to the establishment of a feasible alternative strategy (the sulfur method) for the restoration of the Ph₃PO waste to Ph₃P that is greener and safer than the currently operating “chlorine method” using phosgene.