Esterification of levulinic acid to ethyl levulinate over bimodal micro–mesoporous H/BEA zeolite derivatives

• NaOH treatment to H/BEA zeolite yielded its bimodal micro–mesoporous derivative.
• Enhanced esterification of renewable levulinic acid (LA) to ethyl levulinate (EL).
• H/BEA0.10 exhibited maximum LA conversion of 40 % with 98 % EL selectivity.
• Mesoporosity, crystallinity & acidity of zeolite play crucial role in EL synthesis.

A series of bimodal micro–mesoporous H/BEA zeolite derivatives were prepared by the post-synthesis modification of H/BEA zeolite by NaOH (0.05 M–1.2 M) treatment. Samples were characterized by powder XRD, low temperature nitrogen adsorption/desorption, temperature programmed desorption of ammonia and ICP. The mesopore formation was found to play a crucial role in liquid phase esterification of levulinic acid with ethanol. The enhanced catalytic activity of a bimodal micro–mesoporous H/BEA zeolite derivative (H/BEA0.10) prepared by treatment with 0.1 M NaOH can be mainly attributed to the high mesoporosity coupled with better preserved crystallinity and acidic properties.

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