Catalytic Dehydration Of Fructose Research Articles

Efficient catalytic dehydration of fructose into 5-hydroxymethylfurfural by carbon dioxide

Efficient catalytic dehydration of fructose into 5-hydroxymethylfurfural by carbon dioxide

Catalytic dehydration of fructose into 5-hydroxymethylfurfural by propyl sulfonic acid functionalized magnetic graphene oxide nanocomposite

Covalent immobilization of propyl sulfonic acid groups on the surface of magnetic graphene oxide is reported as an efficient magnetically recoverable solid acid catalyst for the conversion of fructose into 5-hydroxymethylfurfural (5-HMF). The obtained nanocomposite has advantages of both graphene oxide (high surface area) and magnetic nanoparticles (fast and facile separation by a magnet). The numerous reaction parameters including solvent, reaction time, temperature, and amount of catalyst were optimized to attain maximum yield of 5-HMF. The results revealed that fructose could be effectively transformed into 5-HMF with a yield of 87% under the optimized reaction conditions. The catalyst could be magnetically separated from the reaction mixture. Moreover, the catalyst exhibited high stability and could be reused for at least five times without a discernible loss of catalytic performance.

Preparation of kapa carrageenan-based acidic heterogeneous catalyst for conversion of sugars to high-value added materials

A novel composite based on kappa-Carrageenan (κC) was prepared using N,N-methylene bisacrylamide (MBA) as the crosslinking agent. 5-Hydroxymethylfurfural (5-HMF) was produced by catalytic dehydration of fructose and glucose with MBA grafted κC (κC-g-MBA) as the solid acid catalyst due to sulfonic acid groups in biopolymer skeletons. Various reaction parameters such as optimization of the quantity of the catalyst, temperature, reaction time, and solvent were performed. It was established that for fructose dehydration, the best reaction conditions were the 160 °C as the optimized reaction temperature and 1 h reaction time, respectively. Under these conditions, the HMF yield and fructose conversion were 94.2% and 95.5%, respectively. Furthermore, 160 °C and 2 h were the best reaction temperature and reaction time for glucose dehydration, respectively. Under similar conditions, the HMF yield and glucose conversion are 47% and 93%, respectively. The catalyst was readily prepared from inexpensive materials with considerable reusability and reactivity.

Efficient synthesis of diallyl esters of the furan series from fructose and preparation of copolymers on their basis

New unsaturated derivatives of the furan series, diallyl esters of furan-2,5-dicarboxylic acid and 5,5′-[oxybis(methylene)]di(2-furoic acid), which can be used as monomers and cross linking agents, were synthesized by the aerobic oxidation of 5-hydroxymethylfurfural and 5,5′-oxybis(5-methylene-2-furaldehyde) obtained by catalytic dehydration of fructose. Optimum conditions for the synthesis of the above-mentioned compounds and their copolymerization with butyl methacrylate were determined. Varying the amount of the cross-linking agent, the thermal stability, adhesion, strength and optical properties of copolymers can be controlled. New cross-linking agents obtained from renewable resources can be considered as an alternative to the important cross-linking agent, diallyl phthalate, produced from petroleum.

5-Hydroxymethylfurfural production from dehydration of fructose catalyzed by Aquivion@silica solid acid

5-Hydroxymethylfurfural (HMF) production from catalytic dehydration of fructose was studied over mesoporous silica heterogenized perfluorosulfonic acid resin (Aquivion@silica) catalyst. Amphiphilic Aquivion PFSA was used as both acidic and template agent for the sol–gel synthesis of amorphous mesoporous silica which was found very appropriate to effectively immobilize Aquivion resin by using an impregnation method. Various characterizations including elemental analysis, acid-base titration, XRD, FTIR, Raman, N2 adsorption–desorption, SEM and TEM revealed that Aquivion@silica catalyst presented large surface area, sufficient porosity and afforded highly accessible sulfonic acid groups. Efficient and productive HMF production from the dehydration of fructose was achieved in the polar dimethyl sulfoxide (DMSO) solvent at low temperature of 90 °C, i.e. 85% yield of HMF and 43 molHMF molH+ productivity of HMF. The influence of reaction time, reaction temperature, Aquivion loading, catalyst dosage and solvent on the dehydration process was systematically investigated. The catalyst could be regenerated through a simple ion-exchange method and a stable HMF yield was maintained after being used four times.

Carbonaceous microspheres prepared by hydrothermal carbonization of glucose for direct use in catalytic dehydration of fructose

Carbonaceous material prepared from the hydrothermal carbonization of glucose was used directly without anyin situfunctionalization or post-modification, and exhibited good catalytic activity for fructose dehydration to 5-hydroxymethylfurfural.

Relation between surface acidity and reactivity in fructose conversion into 5-HMF using tungstated zirconia catalysts

Catalytic dehydration of fructose and its conversion to 5-hydroxymethylfurfural was studied using tungstated zirconia oxides, with various tungsten oxide loadings (1–20 wt.%). The samples were prepared by incipient wetness impregnation and thoroughly characterized using a combination of different techniques: structural, thermal and calorimetric analyses. Zirconia was predominantly present in the investigated samples in the tetragonal phase when the WO3 loading was above 10 wt.%. The samples exhibited amphoteric characteristics, as they adsorbed both ammonia and sulfur dioxide on their surface. The number of surface acid sites increased with increasing WO3 content. Fructose dehydration tests evidenced the formation of 5-hydroxymethylfurfural and by-products (formic and levulinic acids). The results show that the ratio of basic to acidic sites of the solid catalysts is the key parameter for the selectivity in 5-HMF, while the global fructose conversion was mainly related to the presence of acid sites of a given strength with 150 > Qdiff > 100 kJ·molNH3− 1.

Absence of expected side-reactions in the dehydration reaction of fructose to HMF in water over niobic acid catalyst

The catalytic dehydration of fructose (FRU) to 5-hydroxymethylfurfural (HMF) usually runs with the formation of several side products. Among these, levulinic acid (LA) is often reported as the product of a consecutive reaction of HMF re-hydration. In this work, side reactions of the dehydration of FRU performed in very green conditions (water as solvent and niobic acid as solid catalyst) are taken into account. Experimental evidences are given that, in the used conditions: i) HMF is a final stable product, ii) no formation of LA, either deriving from a consecutive reaction of HMF or directly from FRU transformation, was observed, and iii) LA does not react to give condensation products with any other chemical species present in the reaction mixture.

The Effect of Imidazolium Ionic Liquid on the Dehydration of Fructose to 5‐Hydroxymethylfurfural, and a Room Temperature Catalytic System

The catalytic dehydration of fructose into 5-hydroxymethylfurfural is conducted in an HCl–imidazolium ionic liquid (catalyst–solvent) system, in ambient conditions. High yields and excellent recyclability make the system a promising choice for fructose dehydration. DFT calculations suggest that the solvent “switches” the dehydration from thermodynamically unfavorable into a thermodynamically favorable reaction.

Microreactor Process for the Optimized Synthesis of 5‐Hydroxymethylfurfural: A Promising Building Block Obtained by Catalytic Dehydration of Fructose

AbstractA continuous microreaction process was set up to analyze and improve the “green” synthesis of 5‐hydroxymethylfurfural (5‐HMF) based on the HCl‐catalyzed dehydration of fructose in pure aqueous solutions. The process conditions were deliberately shifted to high temperatures and pressures (185 °C, 17 bar) and combined with a reduced reaction time of only 1 min to avoid extensive rehydration of the product. 5‐HMF was obtained with 75 % selectivity and 54 % yield at 71 % fructose conversion. In comparison to published data, a 24 % increase in selectivity and a 21 % increase in conversion could be achieved. Moreover, by adding organic co‐solvents and extraction agents to the reaction system, both 5‐HMF selectivity and yield could be further enhanced to 85 and 82 %, respectively. However, the use of additional organic solvents cannot be considered as a “green” process anymore.

Catalytic dehydration of fructose into 5-hydroxymethylfurfural by ion-exchange resin in mixed-aqueous system by microwave heating

Catalytic dehydration of fructose into 5-hydroxymethylfurfural by microwave heating was studied in acetone-water mixtures in the presence of a cation exchange resin catalyst. The use of acetone–water reaction media resulted in yields of 5-HMF as high as 73.4% for 94% conversion at 150 °C. It was confirmed that there was no decrease of catalytic activity and selectivity for five reuses of the resin, which was in accordance with the elemental analysis results that showed that sulfonic acid groups attached on the resin were stable at the experimental conditions. A comparison between conventional sand bath heating and microwave heating revealed that the latter had a remarkable accelerating effect not only on fructose conversion, but also on 5-HMF yield. Under the conditions (5 ml of 2 wt% fructose solution, 0.1 g of resin, 150 °C and 10 min), fructose conversion and HMF yields by microwave heating (91.7% and 70.3%, respectively) were higher than those by sand bath heating (22.1% and 13.9% respectively). Therefore, the process that we developed in this study showed that high 5-HMF yields from fructose could be achieved under mild conditions.