Process for the production and separation of 5-hydroxymethylfurfural with quaternary ammonium salts

A process for production and separation of 5-hydroxymethylfurfural (HMF), the process comprising steps of:

• 1) dehydrating a saccharide in the presence of water and a tetraalkylammonium salt, at a temperature between 80-130° C., obtaining a reaction mixture comprising the tetraalkylammonium salt, HMF and any unreacted saccharide;
• wherein step 1) is carried out in the presence of an acid catalyst;
• 2) diluting the reaction mixture with water to form a diluted reaction mixture;
• and
• 3) subjecting said diluted reaction mixture to at least one membrane separation operation selected from the group consisting of nanofiltration, reverse osmosis, electrodialysis and their combinations, obtaining an aqueous permeate comprising HMF and a retentate comprising tetraalkylammonium salt and any unreacted saccharide;
• wherein each of the steps of the process is carried out in the absence of an organic solvent,
• wherein said saccharide is fructose, said tetraalkylammonium salt is tetrabutylammonium bromide (TBAB) and said acid catalyst is selected from sulfuric acid and nitric acid,
• wherein said process comprises, before step 3), a preliminary purification step for removal of high molecular weight compounds, wherein in the said preliminary purification step comprises one or more operations selected from:
• decantation, centrifugation, microfiltration or ultrafiltration, and
• wherein step 3) comprises one or more nanofiltration operations and said membrane separation operation of step 3) uses a nanofiltration membrane, the nanofiltration membrane having a mean pore size in a range of 0.7 nm to 2 nm.