Direct Synthesis of Dialkylphosphites from White Phosphorus

Dialkyl phosphites (DAPIs), traditionally prepared from hazardous and corrosive PCl3, are the fundamental reactive starting materials used in organophosphorus chemistry. Here, a KBr-mediated synthesis of DAPIs involving P-4, alcohols and water is presented. With the use of silica gel as the catalyst, oxone as the safe oxidant, industrially important (EtO)(2)P(O)H, (i-PrO)(2)P(O)H and (MeO)(2)P(O)H are prepared in 70-90% yields. Furthermore, rare metal extractant bis(2-ethylhexyl) phosphate (D2EHPA) is obtained in 73% yield. The reaction is characterized by a complete conversion of white phosphorus. Moreover, this method can be easily adapted to large-scale preparation.

Automated summary

In this study, a KBr-mediated synthesis of DAPIs using P-4, alcohols, and water was developed. The use of silica gel catalyst and safe oxidant oxone enabled the preparation of important DAPIs with yields of 70-90%. Additionally, rare metal extractant D2EHPA was obtained in a yield of 73%. The reaction showed complete conversion of white phosphorus and the method was easily adaptable to large-scale preparation.