Aldol condensation of furfural and acetone on zeolites

• Acidic large pore zeolites are suitable aldol condensation catalysts.
• Internal and external surface of zeolites is involved in the reactions.
• Aldol condensation is accompanied by oligomerization.
• The activity and selectivity of zeolites can be fully restored by regeneration.

Zeolites of different structural types were used as catalysts for aldol condensation of furfural and acetone in batch reaction conditions at T = 20–100 °C and time 0–24 h. To establish a relation between physico-chemical and catalytic properties of microporous materials, the samples were characterized by SEM, N2 adsorption, FTIR and TGA. It was found that the acidic solids possessed appreciable activity in the reaction and resulted in a formation of products of aldehyde–ketone interaction. Nevertheless, furfural conversion decreased rapidly due to coke formation inside zeolite pores. Simultaneously with a general route of the reaction observed for basic catalysts, dimerization of the condensation product on acidic sites occurred. It was supposed that catalytic behavior of zeolites considerably affected by their both structural and textural properties. Experiments with re-used samples showed that zeolites totally restored their activity and selectivity after calcination at 530 °C.

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