Sulfonic acid functionalized ß zeolite as efficient bifunctional solid acid catalysts for the synthesis of 5-hydroxymethylfurfural from cellulose.

Introduction of the sulfonic acid group into H-ß zeolite to prepare ß-SO3H bifunctional catalysts for the efficient synthesis of 5-hydroxymethylfurfural (HMF) from cellulose. Catalysts characterization, such as XRD, ICP-OES, SEM (Mapping), FTIR, XPS, N2 adsorption-desorption isotherm, NH3-TPD, Py-FTIR demonstrate the sulfonic acid group was successfully grafted onto the ß zeolite. A superior HMF yield (59.4 %) and cellulose conversion (89.4 %) was obtained in the H2O(NaCl)/THF biphasic system under 200 °C for 3 h with ß-SO3H(3) zeolite as catalyst. More valuable, ß-SO3H(3) zeolite converts other sugars and obtains ideal HMF yield, including fructose (95.5 %), glucose (86.5 %), sucrose (76.8 %), maltose (71.5 %), cellobiose (67.0 %), starch (68.1 %), glucan (64.4 %) and also converts plant material (25.1 % for moso bamboo and 18.7 % for wheat straw) with great HMF yield. ß-SO3H(3) zeolite catalyst keeps an appreciable recyclability after 5 cycles. Moreover, in the presence of ß-SO3H(3) zeolite catalyst, the by-products during the production of HMF from cellulose were detected, and the possible conversion pathway of cellulose to HMF was proposed. The ß-SO3H bifunctional catalyst has excellent potential for the biorefinery of high value platform compound from carbohydrates.

Hf-ß zeolites as highly efficient catalysts for the production of 5-hydroxymethylfurfural from cellulose in biphasic system.

In this work, a series of (x)Hf-ß zeolite catalysts were prepared by a simple wet impregnation method and used as bifunctional catalysts with Lewis and Brønsted acid sites for synthesizing 5-hydroxymethylfurfural (5-HMF) from cellulose in H2O(NaCl)-THF biphasic system. Characterization analysis of (x)Hf-ß zeolite catalysts with ICP-OES, N2 adsorption-desorption isotherm, XRD, FTIR, SEM, NH3-TPD and Py-FTIR indicated that the catalysts possessed favorable pore structure, appropriate acid strength and acidity. A superior 86.3 % cellulose conversion and 53.4 % 5-HMF yield could be obtained at 200 °C for 4 h by using (5 %)Hf-ß zeolite as the catalyst. In addition, the catalytic system provided a favorable 5-HMF yield from other carbohydrates, including glucose (85.1 %), sucrose (80.6 %), starch (65.1 %), maltose (65.0 %), dextran (59.9 %), and Moso bamboo (21.9 %). Nevertheless, the recyclability of (5 %)Hf-ß zeolite catalyst was unsatisfactory and the 5-HMF yield showed a downtrend from 53.4 % to 24.4 % after 5 cycles. The catalyst has promising potential for converting biomass materials into high-value platform compounds.

Recent Advances of Pervaporation Separation in DMF/H2O Solutions: A Review.

N,N-dimethylformamide (DMF) is a commonly-used solvent in industry and pharmaceutics for extracting acetylene and fabricating polyacrylonitrile fibers. It is also a starting material for a variety of intermediates such as esters, pyrimidines or chlordimeforms. However, after being used, DMF can be form 5-25% spent liquors (mass fraction) that are difficult to recycle with distillation. From the point of view of energy-efficiency and environment-friendliness, an emergent separation technology, pervaporation, is broadly applied in separation of azeotropic mixtures and organic-organic mixtures, dehydration of aqueous-organic mixtures and removal of trace volatile organic compounds from aqueous solutions. Since the advances in membrane technologies to separate N,N-dimethylformamide solutions have been rarely reviewed before, hence this review mainly discusses the research progress about various membranes in separating N,N-dimethylformamide aqueous solutions. The current state of available membranes in industry and academia, and their potential advantages, limitations and applications are also reviewed.

Recent advances in the conversion of furfural into bio-chemicals through chemo- and bio-catalysis.

Furfural is a promising renewable platform molecule derived from hemi-cellulose, which can be further converted to fossil fuel alternatives and valuable chemicals due to its highly functionalized molecular structure. This mini-review summarizes the recent progress in the chemo-catalytic and/or bio-catalytic conversion of furfural into high-value-added chemicals, including furfurylamine, C6 carboxylic acid, i.e., furandicarboxylic acid, furfural alcohol, aromatics, levulinic acid, maleic acid, succinic acid, furoic acid, and cyclopentanone, particularly the advances in the catalytic valorization of furfural into useful chemicals in the last few years. The possible reaction mechanisms for the conversion of furfural into bio-chemicals are summarized and discussed. The future prospective and challenges in the utilization of furfural through chemo- and bio-catalysis are also put forward for the further design and optimization of catalytic processes for the conversion of furfural.

Chemical fixation of CO2 into cyclic carbonates catalyzed by bimetal mixed MOFs: the role of the interaction between Co and Zn.

Bimetal mixed MOFs of [CoZn][(BDC)(DABCO)0.5] (CZ-BDO), [CoNi][(BDC)(DABCO)0.5] (CN-BDO), and [NiZn][(BDC)(DABCO)0.5] (NZ-BDO) were prepared under solvothermal conditions and further employed as highly active accelerants for converting carbon dioxide into cyclic carbonates. The characteristics of the bimetal compounds were revealed via various techniques, including ICP-OES, XRD, FT-IR, Raman, XPS, SEM, EDS maps, N2 adsorption, TG-DTG, and CO2/NH3-TPD. The catalytic results revealed that CZ-BDO is superior to the other samples for obtaining a satisfactory chloropropene carbonate (CPC) yield. The excellent catalytic activity may be owing to the presence of a solid solution within the Co and Zn bimetal sample, which provides synergistic catalysis in the carbon dioxide cycloaddition. In addition, the synergistic catalysis was further confirmed by the NH3-TPD profiles, whereby the amount of CZ-BDO basic sites was obviously enhanced compared to the other samples. Furthermore, DFT calculations were also performed to reveal the synergistic catalysis between Co and Zn for the coupling reaction. Additionally, when the coupling reaction was carried out at 100 °C for 5 h in the presence of 0.5 wt% epichlorohydrin (ECH) as a catalyst at 3.0 MPa, 99.31% conversion of ECH and 97.05% yield of CPC were obtained over the optimal CZ-BDO sample. Moreover, the bimetal sample can also efficiently convert other epoxides into the corresponding cyclic carbonates.

Efficient conversion of 5-hydroxymethylfurfural to high-value chemicals by chemo- and bio-catalysis.

5-hydroxymethylfurfural (HMF) is a very important versatile platform compound derived from renewable biomass. The functionalized molecule with an aldehyde group, a hydroxyl group and a furan ring provides great potential for the production of a wide variety of valuable chemicals. This review highlights the latest advances in the catalytic conversion of HMF into value-added chemicals by some important reactions including (1) aerobic oxidation of HMF into furan-based aldehydes and acids such as 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), 2,5-diformylfuran (DFF), and furandicarboxylic acid (FDCA), (2) reductive amination of HMF to amine, (3) the synthesis of aromatics by Diels-alder reaction followed by a dehydration reaction, (4) catalytic reduction of HMF into 2,5-bis(hydroxymethyl)furan (BHMF), and 2,5-dimethyl furan (DMF), (5) catalytic oxidation of HMF into maleic anhydride, and some other important transformations. The review mainly focuses on the recent progress in bio-catalytic, electrocatalytic, and heterogeneous catalytic transformation of HMF into high value chemicals over the past few years. Moreover, an outlook is provided to highlight opportunities and challenges related to this hot research topic.

Isomerization of glucose into fructose by environmentally friendly Fe/ß zeolite catalysts.

Herein, the environmentally friendly Fe/ß zeolite for glucose isomerization to fructose in aqueous media was reported for the first time. The effects of various reaction conditions including reaction temperature, reaction time, catalyst dosage, etc. on the isomerization reaction over Fe/ß zeolite were studied in detail. Under the optimized conditions, yield of fructose higher than 20% were obtained. Moreover, the Fe/ß zeolite catalysts were stable and remained constant catalytic activity after five consecutive runs. The possible active Fe species for isomerization of glucose in Fe/ß zeolite is also discussed.