The integration of catalyst design and process intensification in the efficient synthesis of 5-hydroxymethyl-2-furancarboxylic acid from fructose

•The integration of catalyst design and process intensification afforded HMFCA directly from fructose with excellent yield.•Water displayed excellent selectivity for target products in the whole process.•Specific process intensification was introduced into the synthesis of HMFCA.•Sulfonic acid and quaternary ammonium salt group catalyzed dehydration reaction synergistically.•Confinement synthesis and replacement of the support improved the sustainability and catalytic activity.