Hydrogen bond induced acidic solids for effective esterification catalysis

The use of Fischer-Speier esterification reaction produced biodiesel as a substitute for fossil fuels has potential to alleviate the climate and energy crisis. However, catalysts for the esterification, such as H2SO4, ionic liquids etc., pose environmental concerns due to their difficulty in reuse, complex synthesis process or the requirement of strong acid treatment. Herein, we try to avoid using common acidification treatments and exploit p-phenyl-enediamine and 1, 3-propanesultone under the intensification of hydrogen bonding donor (HBD) of ethanol to acquire novel chemicals of [N,N-di(propanesulfonic) phenylenediamine][ethanol]2 in one step for the first time. This route triggers hydrogen bond interaction in the produced networks to enable both stable self-solidification and effective esterification catalysis, achieving remarkable 96.3% of esterification conversion that could even suppress homogenous catalysts under very mild conditions, but with easy separation feature. This synthetic method holds great promise for the synthesis of value-added chemicals in a more environmentally friendly manner.