Development of MeSAPO-5 Molecular Sieves from Attapulgite for Dehydration of Carbohydrates

Abstract

The dehydration of carbohydrates to 5-hydroxymethylfurfural (HMF) is still a major challenge in the bioenergy industry. In this study, metal-containing silicoaluminophosphate molecular sieves (MeSAPO-5) with different Si/Al ratios were first synthesized from attapulgite by the hydrothermal method and applied to the dehydration of carbohydrate. The morphology, structure, and acid properties of MeSAPO-5 molecular sieves were studied by XRD, SEM, EDX, TG/DTA, pyrolysis IR (Py-IR), and NH 3 -TPD. The results indicated that MeSAPO-5 catalyst with Si/Al ratio of 0.25 provided much more acid active sites for feasible accessibility of HMF, after partial Al atoms were substituted by Si and Me atoms. The further increase of Si/Al ratio resulted in the decrease of the acidity of the molecular sieves, which significantly influenced their catalytic performance. Over the MeSAPO-5(0.25Si) catalyst, the HMF yield of 73.9% was obtained at 170°C with 2.0 h. This indicated that MeSAPO-5 molecular sieves were a fairly promising catalyst for the carbohydrates dehydration to HMF.

An overview of the biphasic dehydration of sugars to 5-hydroxymethylfurfural and furfural: a rational selection of solvents using COSMO-RS and selection guides

“…A medium H 2 O-DSMO (4 : 6 w/w)/MIBK-2-BuOH (7 : 3 w/w) was used with metal containing silicoaluminophosphate catalysts prepared from attapulgite reaching 74% of yield to 5-HMF. 91 A similar H 2 O-PVP (10 : 1 w/w)/MIBK-2-BuOH (7 : 3 w/w) biphasic system was put to use with EDTA as catalyst, which showed thermoresponsive behaviour being soluble in the RP at 160°C, allowing to obtain yields of up to 89%. In this work, the composition of the loads of the RP and EP was optimized to the values mentioned before, although no great difference in performance was observed in any case.…”

Efficient Conversion of Glucose to 5-Hydroxymethylfurfural over a Sn-Modified SAPO-34 Zeolite Catalyst

“…Apparently, four obvious peaks could be detected in all the tested catalyst samples. The characteristic peak at around 1545 cm –1 was assigned to pyridine adsorbed on Brønsted acid sites (B), and the peak at 1488 cm –1 belonged to an overlap of Brønsted and Lewis acid sites (B + L) . Moreover, Lewis acid sites (L) adsorbed by pyridine were detected at the peaks of 1595 and 1442 cm –1 .…”

Efficient production of 5-hydroxymethylfurfural from fructose over CuAPO-5 molecular sieves synthesized using an ionothermal method

“…For instance, several MeSAPO molecular sieves were produced via the hydrothermal method and catalyzed fructose dehydration in a biphasic system at 170 C to obtain no more than 79% yield of HMF. 14,15 This unsatised HMF yield was inconsistent with the excellent performance of MAPO catalysts in other acid-catalyzed dehydration reaction. 16 Therefore, more fundamental researches should be conducted on the synthesis and catalytic role of MAPO to provide a new choice for HMF production.…”