MODIFIED ZSM-5 ZEOLITES IN THE PROCESS OF MONOSACCHARIDE DEHYDRATION

В данном исследовании была разработана методика синтеза катализаторов на основе цеолитов типа ZSM-5 с различным соотношением Si/Al и количеством кислотных центров, модифицированных оксидом вольфрама (VI). Синтезированные катализаторы были охарактеризованы и протестированы в реакции превращения моносахаридов (фруктозы и глюкозы) в 5-гидроксиметилфурфурол и левулиновую кислоту. Было показано, что введение в состав цеолитов ZSM-5 частиц оксида вольфрама приводит к заметному увеличению количества активных кислотных центров на поверхности катализатора, играющих важную роль в реакции дегидратации моносахаридов. В результате модификации заметно возросла каталитическая активность цеолитов. Результаты исследования показывают перспективность использования цеолитов типа ZSM-5, модифицированных оксидом вольфрама (VI), для конверсии биомассы в платформенные химические соединения. In this study, a method was developed for the synthesis of catalysts based on zeolites of the ZSM-5 type with different Si/Al ratios and the number of acid sites modified with tungsten (VI) oxide. The synthesized catalysts were characterized and tested in the reaction of converting monosaccharides (fructose and glucose) into 5-hydroxymethylfurfural and levulinic acid. It was shown that the introduction of tungsten oxide particles into the composition of ZSM-5 zeolites leads to a noticeable increase in the number of active acid sites on the catalyst surface, which play an important role in the dehydration reaction of monosaccharides. As a result of the modification, the catalytic activity of zeolites has noticeably increased. The results of the study show that the use of zeolites of the ZSM-5 type, modified with tungsten (VI) oxide, is promising for the conversion of biomass into platform chemical compounds.

Mechanistic studies on the formation of 5-hydroxymethylfurfural from the sugars fructose and glucose

In recent years the transformations of fructose and glucose to the platform chemical 5-hydroxymethylfurfural (5-HMF) have been studied extensively, and a variety of mechanisms have been proposed. This review summarizes the varied mechanisms proposed and methods used to study the dehydration of biomass, such as fructose and glucose, to give 5-hydroxymethylfurfural. For fructose dehydration, two main mechanisms have been suggested including a cyclic and an acyclic pathway, of which the cyclic pathway dominates. The conversion of glucose to 5-HMF can proceed either through initial isomerization to fructose or a direct dehydration. For glucose to fructose isomerization, two main reaction pathways have been proposed (1,2-hydride shift and enolization). This review discusses the mechanisms that have been determined based on the evidence from experiments and/or calculations, and briefly introduces the techniques frequently used in such mechanistic studies. Mechanisms in this field are strongly dependent on the nature of the solvent and the catalyst used, so it is important that researchers have a general idea about the existing mechanisms, and the methods and techniques used for investigation, before pursuing their own mechanistic studies.

Selective hydrogenolysis of furfural into fuel-additive 2-methylfuran over a rhenium-promoted copper catalyst

A highly stable rhenium-promoted copper catalyst catalyzes the hydrogenolysis of furfural, a platform chemical derived from sustainable bioresources, into the fuel-additive 2-methylfuran.

Catalytic conversion of glycerol with co-feeds (fatty acids, alcohols, and alkanes) to bio-based aromatics: remarkable and unprecedented synergetic effects on catalyst performance

Glycerol is a bio-based platform chemical that can be converted to a variety of bio-based chemicals via chemical conversions. We here report a catalytic co-conversion strategy where glycerol in combination...

Furfural – A versatile, biomass-derived platform chemical for the production for renewable chemicals

For years, fossil fuels have been the predominant feedstock for the production of chemicals, resulting in their overexploitation and widespread environmental degradation, prompting a search for alternative feedstocks. In this...