TRANSFORMATIONS OF BUTYRALDEHYDE IN THE PRESENCE OF CATALYSTS BASED ON LARGE-PORE MOLECULAR-SIEVES VPI-5 AND ALPO4-8

It is found that zeolite-like crystalline aluminophosphates VPI-5, Si-VPI-5, and Mn-VPI-5 as well as those dirived from them, AlPO4-8, SAPO(4)-8, and MnAPO(4)-8, are capable of catalyzing aldol condensation and crotonization of butyraldehyde (BA). Pd/AlPO4-8 is catalytically active in hydrocondensation of BA with H-2 at atmospheric pressure. The activities in BA conversion to 2-ethylhexane-3-ol-1-al increase in the following order: Mn-VPI-5 < Si-VPI-5 < VPI-5. The same order of activities is also found for AlPO4-8, SAPO(4)-8, and MnAPO(4)-8. These catalysts are characterized by a lower initial activity in crotonization of BA than M(+)NaX (CsNaX), but they are much more stable. Pd/AlPO4-8 catalyzes BA conversion to 2-ethylhexanal even in the absence of H-2 feed to the reaction zone. The influence of catalyst pretreatments and experimental conditions on the catalyst structures and catalytic activities is discussed.