Efficient dehydration of carbohydrates to 5-hydroxymethylfurfural in ionic liquids catalyzed by tin(IV) phosphonate and zirconium phosphonate

In this work, we synthesized tin(IV) phosphonate (SnBPMA) and zirconium phosphonate (ZrBPMA) by the reaction of SnCl4 center dot 5H(2)O or ZrOCl2 center dot 8H(2)O with N,N-bis(phosphonomethyl)aminoacetic acid, which was synthesized from a biomaterial glycine through a Mannich-type reaction. The SnBPMA and ZrBPMA were very efficient heterogeneous catalysts for the dehydration of fructose to produce 5-hydroxymethylfurfural (HMF), and the SnBPMA had higher activity than the ZrBPMA. The effects of solvents, temperature, reaction time, and reactant/solvent weight ratio on the reaction catalyzed by SnBPMA were investigated. It was demonstrated that the yield of HMF could reach 86.5% with 1-ethyl-3-methylimidazolium bromide ([Emim] Br) as solvent, and the SnBPMA and SnBPMA/[Emim]Br catalytic system could be reused five times without considerable reduction in catalytic efficiency. Further study indicated that the SnBPMA and ZrBPMA in [Emim]Br were also effective for the dehydration of sucrose and inulin to produce HMF with satisfactory yields.