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Transformation of 4-hydroxybutanal over porcelain

1999; Elsevier BV; Volume: 144; Issue: 2 Linguagem: Inglês

10.1016/s1381-1169(98)00382-3

1873-314X

Л. Лейте,

Zeolite Catalysis and Synthesis

The transformation of 4-hydroxybutanal (4-HB) in the presence of pretreated porcelain (molar ratio SiO2:Al2O3=6:1) as catalyst has been investigated in a micropulse reactor at 230–300°C in a gas phase. The main reaction of the alcanol was cyclodehydration resulting in 2,3-dihydrofuran (2,3-DHF) formation. Under the conditions studied the significant irreversible adsorption of 4-HB on porcelain is observed, amounting to 1.1×1020 molecules/g at 240°C. The experiments with the mixture of 4-HB and 1,4-butanediol (1,4-BD) indicate that the dehydration reaction of these compounds is of a competitive character. The presence of 4-HB essentially diminishes the 1,4-BD conversion. A theoretical description of 4-HB cyclodehydration and its tautomeric cyclic form at the solid–gas interface is under discussion. The reaction mechanism has been proposed on the basis of the quantum chemical calculations. The conversion of 4-HB and its cyclic form 2-hydroxytetrahydrofuran (2-HTHF) can be interpreted by assuming the concert mechanisms. It is suggested that the Brönsted acidic and basic Si(OH)3O− sites take part in the reactions.