The Experts below are selected from a list of 153117 Experts worldwide ranked by ideXlab platform
Yanqin Wang - One of the best experts on this subject based on the ideXlab platform.
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efficient catalytic conversion of fructose into hydroxymethylfurfural by a novel carbon based Solid Acid
Green Chemistry, 2011Co-Authors: Jianjian Wang, Wenjie Xu, Guanzhong Lu, Yanqin WangAbstract:A novel carbon-based Solid Acid, which was prepared by a facile and eco-friendly approach from glucose and p-toluenesulfonic Acid (TsOH), was used to catalyze fructose dehydration into 5-hydroxymethylfurfural (HMF) for the first time and exhibits excellent catalytic performance. As high as 91.2% yield of HMF was achieved in dimethyl sulfoxide (DMSO) at 130 °C after only 1.5 h. Besides, this catalyst also displayed a good reusability.
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novel sulfonated carbonaceous materials from p toluenesulfonic Acid glucose as a high performance Solid Acid catalyst
Catalysis Communications, 2010Co-Authors: Baohua Zhang, Jiawen Ren, Xiaohui Liu, Yun Guo, Yanglong Guo, Yanqin WangAbstract:Abstract A novel carbon-based Solid-Acid catalyst was simply prepared for the first time by the thermal treatment of p-toluenesulfonic Acid (TsOH) with d -glucose at 180 °C in a sealed autoclave and it was proved to have high Acidity and to be a highly efficient Solid-Acid catalyst in the reactions such as esterification of succinic Acid with ethanol.
Paresh L Dhepe - One of the best experts on this subject based on the ideXlab platform.
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lignin depolymerization into aromatic monomers over Solid Acid catalysts
ACS Catalysis, 2015Co-Authors: Ayillath K Deepa, Paresh L DhepeAbstract:It is imperative to develop an efficient and environmentally benign pathway to valorize profusely available lignin, a component of nonedible lignocellulosic materials, into value-added aromatic monomers, which can be used as fuel additives and platform chemicals. To convert lignin, earlier studies used mineral bases (NaOH, CsOH) or supported metal catalysts (Pt, Ru, Pd, Ni on C, SiO2, Al2O3, etc.) under a hydrogen atmosphere, but these methods face several drawbacks such as corrosion, difficulty in catalyst recovery, sintering of metals, loss of activity, etc. Here we show that under an inert atmosphere various Solid Acid catalysts can efficiently convert six different types of lignins into value-added aromatic monomers. In particular, the SiO2–Al2O3 catalyst gave exceptionally high yields of ca. 60% for organic solvent soluble extracted products with 95 ± 10% mass balance in the depolymerization of dealkaline lignin, bagasse lignin, and ORG and EORG lignins at 250 °C within 30 min. GC, GC-MS, HPLC, LC-MS...
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value addition to lignocellulosics and biomass derived sugars an insight into Solid Acid based catalytic methods
Journal of Chemical Sciences, 2014Co-Authors: Prasenjit Bhaumik, Ayillath K Deepa, Tanushree Kane, Paresh L DhepeAbstract:For the synthesis of important platform chemicals such as sugars (xylose and arabinose) and furans (furfural and 5-hydroxymethylfurfural (HMF)) from carbohydrates (hemicellulose and fructose) Solid Acid catalysts are employed. Similarly, over Solid Acid catalysts, conversion of lignin into aromatic monomers is performed. It is observed that in the dehydration of fructose, because of higher hydrothermal stability, silicoaluminophosphate (SAPO) catalysts give better activity (78% HMF yield) compared with other Solid Acid catalysts (<63% HMF yield) at 175°C. Particularly, SAPO-44 catalyst can be reused at least 5 times with marginal decrease in the activity. Zeolite, HUSY (Si/Al = 15) is active in the conversion of isolated (pure) hemicellulose to produce 41% C5 sugars in water. The catalyst is also active in the selective conversion of hemicellulose from bagasse to yield 59% C5 sugars. It is possible to obtain high yields of furfural (54%) directly from bagasse if instead of water, water+toluene solvent system is used. Depolymerization of lignin using HUSY catalyst produced aromatic monomers with 60% yield at 250°C. A detailed catalyst characterization study is performed to understand the correlation between catalyst activity and morphology. To understand the effect of impurities present in the substrate over Solid Acid catalysts, metal-exchange study is carried out.
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Solid Acid catalyzed depolymerization of lignin into value added aromatic monomers
RSC Advances, 2014Co-Authors: Ayillath K Deepa, Paresh L DhepeAbstract:Depolymerization of lignin to produce value-added aromatic monomers has attracted a lot of attention since these monomers can potentially be used as fuel additives (octane enhancers) and in turn can improve the prospects of cellulosic ethanol technology to become economically feasible. Here we show that Solid Acid catalysts could efficiently convert lignin into value added aromatic monomers with 60% yields and ca. 95% mass balance when depolymerization reactions were carried out at 250 °C for 30–120 minutes. We found that the reaction parameters have a remarkable effect on improving the yields.
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a Solid Acid based process for the conversion of hemicellulose
Green Chemistry, 2010Co-Authors: Paresh L Dhepe, Ramakanta SahuAbstract:We describe a Solid-Acid-catalyzed conversion of hemicellulose (a component of lignocellulosic material) into xylose, arabinose and furfural in aqueous media.
Ibrahim M Lokman - One of the best experts on this subject based on the ideXlab platform.
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investigation of heterogeneous Solid Acid catalyst performance on low grade feedstocks for biodiesel production a review
Energy Conversion and Management, 2017Co-Authors: Nasar Mansir, Yun Hin Taufiqyap, Umer Rashid, Ibrahim M LokmanAbstract:The conventional fossil fuel reserves are continually declining worldwide and therefore posing greater challenges to the future of the energy sources. Biofuel alternatives were found promising to replace the diminishing fossil fuels. However, conversion of edible vegetable oils to biodiesel using homogeneous Acids and base catalysts is now considered as indefensible for the future particularly due to food versus fuel competition and other environmental problems related to catalyst system and feedstock. This review has discussed the progression in research and growth related to heterogeneous catalysts used for biodiesel production for low grade feedstocks. The heterogeneous base catalysts have revealed effective way to produce biodiesel, but it has the limitation of being sensitive to high free fatty Acid (FFA) or low grade feedstocks. Alternatively, Solid Acid catalysts are capable of converting the low grade feedstocks to biodiesel in the presence of active Acid sites. The paper presents a comprehensive review towards the investigation of Solid Acid catalyst performance on low grade feedstock, their category, properties, advantages, limitations and possible remedy to their drawbacks for biodiesel production.
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sub and supercritical esterification of palm fatty Acid distillate with carbohydrate derived Solid Acid catalyst
Chemical Engineering Journal, 2016Co-Authors: Ibrahim M Lokman, Umer Rashid, Motonobu Goto, Yun Hin TaufiqyapAbstract:The esterification of palm fatty Acid distillate (PFAD) in supercritical methanol was investigated by using carbohydrate-derived Solid Acid catalyst. The catalysts were prepared by sulfonation of incomplete carbonized glucose and starch, which had been coded as sulfonated-ICG and sulfonated-ICS, respectively. The contents of fatty Acid methyl ester (FAME) and its yield were determined by using gas chromatography techniques. The effects of sub- and supercritical operating conditions such as methanol/PFAD molar ratio, catalyst amount, reaction temperature and reaction time were analyzed to determine their optimum operating conditions. At optimum reaction temperature of 290 °C, methanol/PFAD molar ratio of 6/1, catalyst amount of 1 wt.% and 5 min reaction time, the esterification of PFAD in supercritical methanol with the presence of sulfonated-ICS and -ICG catalysts resulted 97.3% and 95.4% of FAME; both catalysts yield significantly higher percentages compared to uncatalyzed reaction. Alongside of its potential in enhancing the efficiency of production process, the utilization of carbohydrate-derived Solid Acid catalyst in supercritical methanol method had also resulting fast reaction and energy saving.
Michikazu Hara - One of the best experts on this subject based on the ideXlab platform.
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Biomass conversion by a Solid Acid catalyst
Energy and Environmental Science, 2010Co-Authors: Michikazu HaraAbstract:Amorphous carbon bearing sulfonic Acid groups, a new type of Solid Bronsted Acid catalyst, was investigated for potential application to environmentally benign biodiesel production and cellulose saccharification. The carbon material exhibits much higher catalytic performance for the esterification of higher fatty Acids, transesterification of triglycerides and the hydrolysis of cellulose than conventional Solid Acid catalysts.
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hydrolysis of cellulose by a Solid Acid catalyst under optimal reaction conditions
Journal of Physical Chemistry C, 2009Co-Authors: Daizo Yamaguchi, Satoshi Suganuma, Kiyotaka Nakajima, Masaaki Kitano, Hideki Kato, Michikazu HaraAbstract:The hydrolysis of cellulose with a highly active Solid Acid catalyst, a carbon material bearing SO3H, COOH, and OH groups, was investigated at 323−393 K using an artificial neural network (ANN) and a response surface methodology (RSM). The ANN models developed for experimental design accurately reflect the novel Solid−Solid interface catalysis. The ANN models and RSM revealed that the amount of water dominates the hydrolysis reaction as well as cellulose saccharification by concentrated sulfuric Acid, a conventional saccharification method. The correlations of the reaction and each parameter are discussed on the basis of the reaction mechanism, ANN, and RSM.
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esterification of higher fatty Acids by a novel strong Solid Acid
Catalysis Today, 2006Co-Authors: Atsushi Takagaki, Shigenobu Hayashi, Kazunari Domen, Junko N. Kondo, Masakazu Toda, Mai Okamura, Michikazu HaraAbstract:Carbon material prepared from d-glucose has been examined as a Solid Acid catalyst. Sulfonation of incompletely carbonized d-glucose results in amorphous carbon consisting of small polycyclic aromatic carbon sheets with high density of SO3H groups. The carbon material exhibits remarkable catalytic performance for the esterification of higher fatty Acids. This can be attributed to high density of SO3H groups with strong Acidity in the material.
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Exfoliated nanosheets as a new strong Solid Acid catalyst
Journal of the American Chemical Society, 2003Co-Authors: Atsushi Takagaki, Michikazu Hara, Kazunari Domen, Mariko Sugisawa, Junko N. Kondo, Shigenobu HayashiAbstract:Two-dimensional metal oxide sheets in HTiNbO5 and HSr2Nb3O10, cation-exchangeable layered metal oxides, were examined as Solid Acid catalysts. Exfoliation of HTiNbO5 and HSr2Nb3O10 in aqueous solutions formed colloidal single-crystal TiNbO5- and Sr2Nb3O10- nanosheets, which precipitated under an Acidic condition to form aggregates of HTiNbO5 nanosheets and HSr2Nb3O10 nanosheets. Although esterification of acetic Acid, cracking of cumene, and dehydration of 2-propanol were not catalyzed by original HTiNbO5 because of the narrow interlayer distance, which prevents the insertion of organic molecules, HTiNbO5 nanosheets functioned as a strong Solid Acid catalyst for the reactions. Nanosheets of HSr2Nb3O10 exhibited no or slight catalytic activity for these reactions. NH3 temperature-programmed desorption and 1H magic-angle spinning nuclear magnetic resonance spectroscopy revealed that HTiNbO5 nanosheets have strong Bronsted Acid sites, whereas HSr2Nb3O10 nanosheets do not.
Xuezheng Liang - One of the best experts on this subject based on the ideXlab platform.
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Polyacrylonitrile Fiber Mat Supported Solid Acid Catalyst for Acetalization.
ChemInform, 2012Co-Authors: Linjun Shao, Guiying Xing, Xuezheng LiangAbstract:A novel polyacrylonitrile hybrid fiber mat-supported Solid Acid catalyst is produced by electrospinning of polyacrylonitrile with a Solid Acid prepared from polyvinyl alcohol and hydroxyethylsulfonic Acid.
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polyacrylonitrile fiber mat supported Solid Acid catalyst for acetalization
Monatshefte Fur Chemie, 2012Co-Authors: Linjun Shao, Guiying Xing, Xuezheng LiangAbstract:A novel polyacrylonitrile hybrid fiber mat supported Solid Acid catalyst was prepared by electrospinning, and its catalytic activities were carefully investigated through acetalization reactions. The results showed that this hybrid fiber mat exhibits high activity for the reactions, with average yields over 95%. Besides having catalytic activities similar to the Solid Acid, the heterogeneous Solid Acid/polyacrylonitrile mat can be reused in six runs without significant loss of catalytic activities. The large size of the hybrid fiber mat greatly facilitates recovery of the catalyst from the reaction mixture. The high and stable catalytic activities of the hybrid fiber mat hold great potential for green chemical processes and preparation of membrane reactors in the future. .
