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Herein, we report the efficacy of Brønsted acid‐functionalized CDs in an enriched preparation of 5‐hydroxymethylfurfural (HMF) and ethyl levulinate (EL) energy fuel building‐block compounds. The cheap p‐toluenesulphonic acid was used as a precursor to prepare CD‐SO3H by employing a simple, one‐pot and scalable protocol. The high‐end analytical techniques endorsed the catalyst's higher acid density and minimum particle size characteristics. Its glucose reaction evaluation resulted in an 82 mol% HMF using glucose via dehydration. Similarly, it enabled an 85 mol% EL from levulinic acid via esterification under modest reaction conditions. It also promoted the synthesis of other varieties of alkyl levulinates (such as levulinic acid 1‐butyl and methyl esters) with a similar yield result. The recyclability study showed that it could be reused for up to 5 cycles. Overall, the catalytic setup represented an environmentally‐friendly and feasible method for process development.

This study presents a method for the economical production of fructose and allulose (a valuable byproduct) directly from glucose over a MgO/CaO nanocomposite under an aqueous condition. The catalyst containing MgO and CaO at equal proportions helped manipulate the inherent characteristics of CaO, particularly strong basicity and surface properties. The analytical characterizations revealed that the structural assembly is such that MgO settles at the surface to initiate the isomerization reaction by providing a higher number of weak/medium base sites. The CaO present beneath undertakes the sequential conversion of the enolintermediate to ultimate fructose and byproducts (mannose and allulose). Thus, the catalyst accelerated the glucose interconversion to obtain a fructose yield as high as 33 wt % with 80% selectivity within 15 min. At the same time, it also initiated the C-3 fructose epimerization to yield allulose (a low-calorie sugar molecule). Moreover, the adopted deep neural network modeling well predicted the catalytic response with the MAE <5%. The technoeconomic analysis estimated the minimum selling price of different products to be US $ ∼4/kg (fructose), $ ∼4/kg (mannose), and $ ∼10/kg (allulose).

Here, we describe the maximum production of 5‐HMF using glucose over Sn doped Ta2O5 in a binary solvent system. The analytical characterizations established that Sn4+ in the catalyst interacts with Ta2O5 and offers the Lewis acid sites favorable for glucose isomerization to fructose. Similarly, the Ta2O5 support offers both the Lewis and Brønsted acid sites to promote fructose dehydration to 5‐HMF. The catalyst provided favorable conditions for the sequential sugar(s) transformation, i. e., glucose isomerization followed by fructose dehydration, which resulted in a 5‐HMF yield as high as 57 % wt. and 80 % selectivity under modest reaction conditions in a water‐DMSO system using ST1 (1 % Sn on Ta2O5). The separate fructose to 5‐HMF conversion study verified the negligible influence of Sn on the dehydration reaction. Moreover, the catalyst's systematic sugar conversion enabled a >65 % fructose formation, which accounts for the enriched 5‐HMF synthesis. The neural network model best represented the 5‐HMF data (<4 % MAE for glucose and fructose conversions).

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