Efficient and safe conversion of 5-hydroxymethylfurfural to 5-hydroxymethyl-2-furancarbonitrile with hydroxylamine zinc chloride salt

Abstract

Efficient and safe conversion of 5-hydroxymethylfurfural (HMF) to 5-hydroxymethyl-2-furancarbonitrile (HMFC) with hydroxylamine zinc chloride salt (ZnCl2·2NH2OH) obtained from a novel method was developed. Without a catalyst, free NH2OH could react with HMF to produce HMFC with a yield of 41% at 55 °C. ZnCl2 was an appropriate catalyst that increased HMFC yield to 64%. However, the reaction has a potential explosion safety hazard and a low effective utilization rate of NH2OH due to the easy decomposition property of free NH2OH. To address these issues, ZnCl2·2NH2OH was prepared to serve as a hydroxylamine stabilizer, catalyst, and nitrogen source in the synthesis of HMFC. Therefore, NH2OH could be slowly released to participate in the reaction, slowing the invalid decomposition and increasing the utilization rate of elemental N. Under optimal conditions of n(HMF): n(NH2OH) = 1:1.5, 100 °C for 20 min with acetonitrile as solvent, the yield of HMFC was 100%. A plausible reaction mechanism for HMFC synthesis was also proposed.