Effect of the Solvent on the Basic Properties of Mg–Al Hydrotalcite Catalysts for Glucose Isomerization

Abstract

We suggested the existence of a relationship between the base properties of Mg–Al hydrotalcite catalysts and the solvents employed in the industrially important isomerization of glucose produce fructose. We prepared Mg–Al hydrotalcite catalysts with different Mg/Al atomic ratios to tune the basic properties of the catalyst. The prepared catalysts were used in the glucose isomerization conducted in various solvents. Experimental results confirmed that the catalysts exhibited different activities in the different solvents. We also implemented the Hammett indicator method, which allows to analyze the basic properties of the catalysts in various solvents. According to evidence, the basic properties of the catalysts varied substantially in different solvents. Notably, increases in the catalysts’ base properties matched the observed increases in fructose yield of the glucose isomerization. Consequently, we suggested that, in order to prepare efficient Mg–Al hydrotalcite catalysts for glucose isomerization, the interaction between the solvent used to conduct the reaction and the basic properties of the catalyst, which are in turn influenced by the solvent, should be considered.

Study on Leaching of Phosphate from Municipal Wastewater Treatment Plant’s Sewage Sludge and Followed by Adsorption on Mg‐Al Layered Double Hydroxide

“…It also reveals relatively obvious hexagon overlapping crystals, which are typical for LDHs. The morphology features do not change after the adsorption and are similar to those observed in previous studies [14,30,36].…”

Stannate-catalysed glucose–fructose isomerisation in alcohols

“…The catalytical activity of solid basic hydrotalcite catalysts for glucose–fructose isomerisation has been found to depend on the surface properties of the catalysts, which in turn are affected by the solvent. 49 The solvent also affects the ionisation constants of sugars as well as the rate-limiting formation and stability of the enediol anion intermediate formed during base-catalysed glucose–fructose isomerisation with e.g. amines.…”

Aluminum‐Containing Metal‐Organic Frameworks as Selective and Reusable Catalysts for Glucose Isomerization to Fructose

“…Researchers have investigated the effect of non‐aqueous solvents on glucose‐fructose isomerization because non‐aqueous solvents can improve solubilities of reactants/products, conversion rates, and selectivities to desired products [73–74] . Such non‐aqueous solvents include alcohols, [34,75] DMSO, [76] and DMA [77–78] . Yabushita et al [79] .…”

“…[73][74] Such non-aqueous solvents include alcohols, [34,75] DMSO, [76] and DMA. [77][78] Yabushita et al [79] reported superior fructose selectivity (> 78%) and glucose conversion (> 55%) by MgÀ Al hydrotalcite in primary alcohols (methanol, ethanol, and 1-propanol) to those in water at 90 °C for 2 h. de Mello et al [26] modulated UiO-66(Zr) to create Lewis acid sites for glucose isomerization in alcohols. They found that reaction in 1propanol gave the highest fructose selectivity of 73% at 82% glucose conversion.…”