Formaldehyde base catalysis by NaX zeolite

Reactions of formaldehyde to produce formose sugars at 95°C in aqueous solutions were studied over a trickle bed of NaX Zeolite spheres. When effluent pH was in the range of 5 to 7, a rapid irreversible catalyst deactivation from an initial 50% conversion occurred. The catalyst was destroyed in less than five hours by formic acid produced by the undesired Cannizzaro reaction. Incorporation of 0.86 mol NaOH/mol HCHO at 1.21 LHSV into the combined feed to the reactor maintained the effluent pH in the range of 10 to 12. Conversion of HCHO fell only from 95 to 92% in three hours, and selectively to Cannizzaro reaction was reduced to approximately 25%.

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, , 95°C , NaX. pH 5÷7, , 50%- . , 5 . . 0,86 NaOH 1 HCHO 1,21 pH 10÷12. HCHO 95 92%, 25%.