- Utilization of renewable resources: Investigation on role of active sites in zeolite catalyst for transformation of furfuryl alcohol into alkyl levulinate
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A bio-derived furfuryl alcohol transformation into various high-value chemicals is a growing field of interest among researchers. This study reports an exclusive investigation of the porosity and active sites responsible for the efficient alcoholysis of furfuryl alcohol to alkyl levulinate by the aid of zeolite catalyst. Alkyl levulinate is a promising platform chemical potentially used as a fuel additive and also for the production of chemicals. A detailed study using well-characterized HZSM-5 catalyst on the influence of acidity and post synthesis modification like desilication, dealumination, metal ion exchange and phosphate modification revealed the most desired type of acid sites required to catalyze this reaction. Among the HZSM-5 catalysts tested, HZSM-5 (SAR 95) showed the best performance of ≥ 99 % furfuryl alcohol conversion and 85 % butyl levulinate selectivity under optimum conditions. The catalyst exhibited good recyclability additionally addressing all the challenges reported in the previous literature fulfilling the green chemistry principles.
- Vaishnavi,Sujith,Kulal, Nagendra,Manjunathan, Pandian,Shanbhag, Ganapati V.
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- The selective conversion of furfuryl alcohol to ethyl levulinate over Zr-modified tungstophosphoric acid supported on β-zeolites
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Catalysts of zirconium-exchanged proton-containing tungstophosphoric acid (TPA) supported on β-zeolites were prepared by an impregnation method for the selective alcoholysis of furfuryl alcohol into ethyl levulinate. The prepared catalysts were characterized by different spectroscopic techniques. The results indicated the existence of a Keggin ion structure of TPA after its modification with Zr ions and successive dispersion on β-zeolites. The introduction of Zr in TPA generated Lewis acidic sites in the catalyst. Pyridine-adsorbed FT-IR confirmed the presence of both Br?nsted and Lewis acidic sites in catalysts. The catalytic activity for the alcoholysis of furfuryl alcohol depends on the strength of both Br?nsted and Lewis acids of the catalyst. Among these catalysts, 20%Zr0.75TPA/β-zeolite was active for the alcoholysis of furfuryl alcohol with a 96% yield of ethyl levulinate. Optimal conditions were established to obtain maximum yield. A plausible reaction mechanism was also proposed. The catalyst was reused without any appreciable loss of activity.
- Yogita,Rao, B. Srinivasa,Subrahmanyam, Ch.,Lingaiah
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p. 3224 - 3233
(2021/02/26)
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- Etherification of biomass-derived furanyl alcohols with aliphatic alcohols over silica-supported nickel phosphide catalysts: Effect of surplus P species on the acidity
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The acidity of nickel phosphide (Ni2P) catalysts plays a crucial role in producing a desired hydrodeoxygenation molecule from biomass-derived substrates; yet, it has never been explored in acid-catalyzed reactions. Herein, we demonstrated the activity of silica-supported Ni2P catalyst prepared with the nominal P/Ni ratio of 2 (Ni2P/SiO2-2P) in the etherification of furanyl alcohols (particularly, 5-(hydroxymethyl)furfural) with aliphatic alcohols including ethanol. By comparing the characteristics of Ni/SiO2, PxOy/SiO2, and Ni2P/SiO2-xP (x = 0.5 and 1), Ni2P/SiO2-2P was revealed to contain the Br?nsted and Lewis acid sites of which both contributed to the etherification reaction. Notably, the Br?nsted acidity was associated with the surplus P species added to produce the Ni2P phase. Consequently, supported Ni2P catalysts can work in acid-catalyzed reactions if an adequate ratio of Br?nsted to Lewis acid sites is provided by the amount of the surplus P species determined by adjusting the P/Ni ratio.
- Kim, Jinsung,Shin, Mi,Suh, Young-Woong
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- Efficient synthesis of niobium pentoxide nanowires and application in ethanolysis of furfuryl alcohol
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Nb2O5 nanowires with high specific surface area and crystallinity were prepared by using ammonium oxalate and an acetic acid solvent system. The nanomaterial was applied in ethanolysis of furfuryl alcohol (FA), and the yield of the product, 2-(ethoxymethyl)furan (FEE), achieved was up to 79.6%. Compared to mesoporous Nb2O5 materials and other porous materials, the residence time of FEE on the surface of the catalyst is shorter, and the yield of ethyl levulinate (EL) is lower. Furthermore, a high temperature calcination treatment can change the acid sites and acidity type distribution on the nanowire surface. By XRD, NH3-TPD, IR, and TG-DTA determination methods, it was found that the weak and medium-strong acid sites on the surface of Nb2O5 nanowires were reduced after a 300 °C treatment, and the amount of strong acid was relatively higher. According to the catalytic performance test data and acidity determination, it was concluded that more weak acid and medium-strong acid sites improve the conversion of furfuryl alcohol to FEE, and the strong acid sites promote further conversion of FEE to EL.
- Zhang, Zhenwei,Wang, Peng,Wu, Zeying,Yue, Chuanjun,Wei, Xuejiao,Zheng, Jiwei,Xiang, Mei,Liu, Baoliang
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p. 5690 - 5696
(2020/02/26)
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- SINGLE STEP PROCESS FOR THE SYNTHESIS OF FURFURYL ETHYL ETHER
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The present invention provides a single step process for the synthesis of furfuryl ethyl ether comprises refluxing the reaction mixture of furfuryl alcohol, ethanol and catalyst at temperature in the range of 80 to 120° C. for the period in the range of 3 to 7 hrs to afford furfuryl ethyl ether. The catalyst used in present invention is Zr incorporated SBA-15. Further, the conversion of furfuryl alcohol is in the range of 60 to 90%. The selectivity of reaction towards furfuryl ethyl ether is in the range of 85 to 95%.
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Paragraph 0048
(2019/07/29)
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- Facile synthesis of furfuryl ethyl ether in high yield: Via the reductive etherification of furfural in ethanol over Pd/C under mild conditions
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The one-pot synthesis of furfuryl ethyl ether (FEE) over Pd nanoparticles supported on TiO2, Al2O3, SiO2, and active carbon via the catalytic reductive etherification of furfural in ethanol was systematically studied. The Pd nanoparticles supported on SiO2, TiO2 and active carbon are all active for this novel process under mild reaction conditions, with Pd/C showing the highest selectivity to FEE. The effects of palladium loading, reaction temperature, and hydrogen pressure on the activity and selectivity of Pd/C have been investigated in detail. The results demonstrate that suitable Pd amount, low reaction temperature of about 60 °C, and low H2 pressure of about 0.3 MPa are favorable for the formation of the desired ether product. Under the optimized conditions, an unprecedented high yield of up to 81% of FEE was firstly obtained with the major by-products being furfuryl alcohol and 2-methyltetrahydrofuran. Compared with the conventional hydrogenation-etherification route via furfural alcohol as a reaction intermediate, the reductive etherification shows significant advantage in product yield because of its much lower reaction temperature that is required.
- Wang, Yun,Cui, Qianqian,Guan, Yejun,Wu, Peng
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supporting information
p. 2110 - 2117
(2018/05/24)
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- Catalytic Transfer Hydrogenation of Furfural to Furfuryl Alcohol by using Ultrasmall Rh Nanoparticles Embedded on Diamine-Functionalized KIT-6
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A Rh/ED-KIT-6 catalyst comprised of Rh nanoparticles embedded on mesoporous silica (KIT-6) functionalized with N1-[3-(trimethoxysilyl)propyl]ethane-1,2-diamine was synthesized by Rh3+ adsorption and chemical reduction in the liquid phase. The structure of ED-KIT-6 and textural properties of the pristine and supported Rh catalysts, as well as particle size and chemical state of the Rh species were examined by various analytical methods. The homogeneous dispersion of ultrasmall Rh nanoparticles, approximately 1.2 nm in size, stabilized by the grafted diamine (ED) species was confirmed. Rh/ED-KIT-6 was applied to the transfer hydrogenation of furfural (FFR) to furfuryl alcohol (FAL) by using formic acid (FA) as the hydrogen source. The effect of the solvent and reaction parameters, such as temperature, reaction time, and FA/FFR ratio, were investigated. The Rh-embedded catalyst exhibited a significantly high turnover frequency (TOF≈204 h?1) to that of Ru, Pd, or Ni-based catalysts on KIT-6. A plausible reaction mechanism was proposed after examining an independent FA decomposition reaction over the same Rh-ED-KIT-6 catalyst. The heterogeneity of the catalyst was verified by a hot filtration experiment. The Rh/ED-KIT-6 could be reused for up to three cycles without any decrease in catalytic activity and selectivity, but the slow oxidation of Rh species was detected.
- Neeli, Chinna Krishna Prasad,Chung, Young-Min,Ahn, Wha-Seung
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p. 4570 - 4579
(2017/11/29)
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- Catalytic upgrading of furfuryl alcohol to bio-products: Catalysts screening and kinetic analysis
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The conversion of furfuryl alcohol, a highly versatile biomass-derived platform molecule, into a large variety of bio-products, including ethers, lactones and levulinates, has been evaluated in alcohol media using different solid acid catalysts, such as commercial zeolites, sulfonic acid-functionalized materials, and sulfated zirconia. Reaction pathways and mechanisms have been correlated to the particular type of catalyst used, aiming to establish the influence of the main physico-chemical properties of the materials on the extent of furfuryl alcohol conversion, as well as on the predominant reaction pathway followed. Mechanistic and kinetics modelling studies for each type of catalyst have been developed and compared, providing an useful tool for the selection of the most suitable solid acid catalyst for the production of each of the reaction intermediates in the cascade from furfuryl alcohol to alkyl levulinate.
- Paniagua,Melero,Iglesias,Morales,Hernández,López-Aguado
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- Preparation method for furfuryl alkyl ether
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The invention discloses a preparation method for furfuryl alkyl ether through reaction of furfuryl alcohol and monohydric alcohol. The preparation method comprises the following steps: dissolving furfuryl alcohol in monohydric alcohol in a reaction kettle; then adding a catalyst; and next carrying out a reaction for 1-24 hours at the temperature of 150-260 DEG C, and thus obtaining the furfuryl alkyl ether. The preparation method is simple in process and easy to control, only adopts an inorganic metal oxide as the catalyst, has no addition of organic acids and alkalis, inorganic acids and alkalis or other co-catalysts, is convenient for separation of the catalyst and other operations, and is conducive to large-scale industrialized production.
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Paragraph 0034-0035; 0042-0043
(2017/06/10)
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- Magnetically separable sulfated zirconia as highly active acidic catalysts for selective synthesis of ethyl levulinate from furfuryl alcohol
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Magnetically separable sulfated zirconia catalysts were prepared by a two-step approach. Coating of zirconia around the particles helps to increase the number of sites needed for sulfate ion loading and hence enhances the acidity of the catalyst. Different molar concentrations of chlorosulfonic acid were used for sulfonation. The prepared catalysts were used for selective synthesis of ethyl levulinate using renewable substrates: furfuryl alcohol and ethanol. Ethyl levulinate has many applications in different industries including as a potential blending component in biodiesel. The catalyst could be easily separated by the use of a magnet. The influence of different parameters was investigated to reach the optimum yield of ethyl levulinate. Detailed kinetics were established for scaling up purposes. The catalyst is robust and reusable.
- Tiwari, Manishkumar S.,Gawade, Anil B.,Yadav, Ganapati D.
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p. 963 - 976
(2017/03/15)
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- Ethane-Bridged Organosilica Nanotubes Functionalized with Arenesulfonic Acid and Phenyl Groups for the Efficient Conversion of Levulinic Acid or Furfuryl Alcohol to Ethyl Levulinate
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A series of ethane-bridged organosilica nanotubes functionalized with arenesulfonic acid and phenyl groups (ArSO3H-Si(Et)Si-Ph-NTs) was fabricated successfully by a P123-directed sol–gel co-condensation route combined with hydrothermal treatment with a carefully adjusted P123-to-bis-silylated organic precursor-to-HCl molar ratio in the starting system. The morphological characteristics, textural properties, Br?nsted acidity, surface hydrophobicity, and structural integrity of the carbon/silica framework were characterized. The ArSO3H-Si(Et)Si-Ph-NTs materials were applied in the synthesis of ethyl levulinate from the esterification of levulinic acid and the ethanolysis of furfuryl alcohol, and the excellent catalytic activity was explained in terms of the strong Br?nsted acidity, unique hollow nanotube morphology, and enhanced surface hydrophobicity. Reusability tests confirmed that ArSO3H-Si(Et)Si-Ph-NTs can be reused for three or five times without a significant loss of activity.
- Song, Daiyu,An, Sai,Sun, Yingnan,Zhang, Panpan,Guo, Yihang,Zhou, Dandan
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p. 2037 - 2048
(2016/07/07)
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- Efficient conversion of levulinic acid or furfuryl alcohol into alkyl levulinates catalyzed by heteropoly acid and ZrO2 bifunctionalized organosilica nanotubes
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A series of heteropoly acid and ZrO2 bifunctionalized organosilica nanotubes (PW12/ZrO2-Si(Et)Si-NTs) were fabricated via a P123 single-micelle-templated sol-gel co-condensation route and carefully adjusted Si-to-Zr molar ratio and acidity in the initial gel mixture. The morphological characteristics, textural properties, Bronsted and Lewis acidity, and structural integrity of the incorporated Keggin units, as well as the formation of the carbon/silica framework, were well characterized. The PW12/ZrO2-Si(Et)Si-NTs hybrid nanocatalysts were applied in the synthesis of alkyl levulinates by esterification of levulinic acid and ethanolysis of furfuryl alcohol, and the obtained excellent catalytic activity was explained in terms of the strong Bronsted and Lewis acidity, unique hollow tubular nanostructure, and hydrophobic surface of the hybrid nanocatalysts; additionally, the catalysts could be reused at least three times without significant loss of activity. Finally, the possible reaction mechanism of the PW12/ZrO2-Si(Et)Si-NTs-catalyzed esterification and ethanolysis reactions were put forward.
- Sun, Yingnan,Guo, Yihang,Song, Daiyu,An, Sai
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p. 184 - 199
(2015/12/30)
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- Efficient conversion of furfuryl alcohol to ethyl levulinate with sulfonic acid-functionalized MIL-101(Cr)
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Catalytic ethanolysis of furfuryl alcohol (FA) to ethyl levulinate (EL) with MIL-101(Cr)-SO3H, prepared by simple one-pot hydrothermal treatment, is presented for the first time. The as-prepared catalyst with high surface area, hydrothermal and chemical stability, good dispersion, and feasible accessibility of -SO3H Br?nsted acid sites was found to show superior performance to other sulfonic acid-functionalized solid catalysts. Besides the special textural properties, the obtained good catalytic activity of 79.2% EL yield and 100% FA conversion were also dependent on the density and strength of the Br?nsted acid and the reaction parameters. A slight loss of catalytic activity after five consecutive recycles and the hot filtration experiment confirmed the good stability of MIL-101(Cr)-SO3H. Two coexisting reaction paths for the ethanolysis of FA to EL catalyzed by MIL-101(Cr)-SO3H were proposed, wherein 2-ethoxymethylfuran (2-EMF) was observed to be the dominant intermediate.
- Liu, Xiao-Fang,Li, Hu,Zhang, Heng,Pan, Hu,Huang, Shan,Yang, Kai-Li,Yang, Song
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p. 90232 - 90238
(2016/10/09)
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- One step synthesis of ethyl levulinate biofuel by ethanolysis of renewable furfuryl alcohol over hierarchical zeolite catalyst
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Ethanolysis of renewable furfuryl alcohol (FAL) to ethyl levulinate (EL) biofuel over various zeolites viz. H-ZSM-5 (microporous, medium pore), Hierarchical-HZ-5 (combination of micro- and meso pore), H-Beta (microporous, large pore) and Ultra Stable Y (USY, microporous, large pore) was studied in detail. To the best of our knowledge, probably for the first time, Hierarchical-HZ-5 synthesized by desilication post-treatment has been employed as a heterogeneous catalyst for ethanolysis of FAL. The synthesized catalysts were characterized by powder X-ray diffraction (PXRD), temperature programmed NH3 desorption (TPAD), Energy dispersive X-ray analysis (EDAX), etc. Response surface methodology (RSM) with Box-Behnken experimental design (BBD) was used to investigate the influence of three crucial process variables of ethanolysis such as ethanol to FAL molar ratio, percent catalyst loading and reaction temperature on EL yield. The optimization tool of design expert software was employed to obtain the optimum reaction parameters for FAL ethanolysis over Hierarchical-HZ-5 catalyst. Three intermediates of FAL ethanolysis reaction such as, ethoxymethylfuran (EMF), 4,5,5-triethoxypentan-2-one and diethyl ether (DEE) have been identified and quantified from the product mixture with the aid of Gas Chromatography-Mass Spectroscopy (GC-MS). Hierarchical-HZ-5 was found to be a potential catalyst for ethanolysis of FAL with 73% EL yield and 26% EMF yield at optimized process parameters.
- Nandiwale, Kakasaheb Y.,Pande, Ashwini M.,Bokade, Vijay V.
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p. 79224 - 79231
(2015/10/05)
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- Indium(III) triflate promoted synthesis of alkyl levulinates from furyl alcohols and furyl aldehydes
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A facile protocol for the alcoholysis of furfuryl alcohol into levulinate esters has been developed employing low catalyst loadings of indium(III) triflate. This method provides a rapid and efficient route for the synthesis of these useful materials. The alcoholysis reactions of 5-hydroxymethylfurfural (HMF), furfural and furfural dimethylacetal were also investigated under these reaction conditions.
- Kean, Jacqueline R.,Graham, Andrew E.
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p. 175 - 179
(2015/02/19)
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- Graphene oxide: An efficient acid catalyst for alcoholysis and esterification reactions
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Evidence is presented for graphene oxide (GO), prepared by modified Hummers method, as a highly active, selective and reusable solid-acid catalyst for the production of alkyl levulinates via alcoholysis or esterification. 95.5% yield of ethyl levulinate was achieved by GO in furfuryl alcohol alcoholysis. Moreover, the surface SO3H groups were identified as the primary active sites, while the surface carboxyl groups worked synergistically to adsorb furfuryl alcohol.
- Zhu, Shanhui,Chen, Chengmeng,Xue, Yanfeng,Wu, Jianbing,Wang, Jianguo,Fan, Weibin
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p. 3080 - 3083
(2015/02/02)
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- Mesoporous carbon-silica solid acid catalysts for producing useful bio-products within the sugar-platform of biorefineries
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Useful bio-products are obtainable via the catalytic conversion of biomass or derived intermediates as renewable carbon sources. In particular, furanic ethers and levulinate esters (denoted bioEs) have wide application profiles and can be synthesised via acid-catalysed reactions of intermediates such as fructose, 5-hydroxymethyl-2-furaldehyde (HMF) and furfuryl alcohol (FA) with ethanol. Solid acid catalysts are preferred for producing the bioEs with environmental benefits. Furthermore, the versatility of the catalyst in obtaining the bioEs from different intermediates is attractive for process economics, and in the case of porous catalysts, large pore sizes can be beneficial for operating in the kinetic regime. Carbon-based materials are attractive acid catalysts due to their modifiable surface, e.g. with relatively strong sulfonic acid groups (SO3H). Considering these aspects, here, we report the preparation of mesoporous (SO3H)-functionalised-carbon/ silica (C/S) composites with large pores and high amounts of acid sites (up to 2.3 mmol g-1), and their application as versatile solid acid catalysts for producing bioEs from fructose, HMF and FA. The mesoporous composites were prepared by activation of an organic compound deposited on the ordered mesoporous silicas MCF (mesostructured cellular foam) and SBA-15, where the organic compound (p-toluenesulfonic acid) acted simultaneously as the carbon and SO3H source. The atomic-level characterisation of the acid nature and strengths was performed by 31P solid-state NMR studies of an adsorbed base probe, in combination with FT-IR and XPS. Comparative catalytic studies showed that the C/S composites are interesting catalysts for obtaining bioEs in high yields, in comparison with classical solid acid catalysts such as sulfonic acid resin Amberlyst-15 and nanocrystalline (large pore) zeolite H-beta. the Partner Organisations 2014.
- Russo, Patricia A.,Antunes, Margarida M.,Neves, Patricia,Wiper, Paul V.,Fazio, Enza,Neri, Fortunato,Barreca, Francesco,Mafra, Luis,Pillinger, Martyn,Pinna, Nicola,Valente, Anabela A.
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supporting information
p. 4292 - 4305
(2014/11/07)
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- Solid acid-catalyzed conversion of furfuryl alcohol to alkyl tetrahydrofurfuryl ether
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The acidic zeolite HZSM-5 (Si/Al = 25) achieved 58.9% selectivity of methyl furfuryl ether (MFE) and 44.8% selectivity of ethyl furfuryl ether (EFE) from etherification of furfuryl alcohol with methanol and ethanol. MFE and EFE were quantitatively hydrogenated into methyl tetrahydrofurfuryl ether (MTE) and ethyl tetrahydrofurfuryl ether (ETE) using a Raney Ni catalyst.
- Cao, Quan,Guan, Jing,Peng, Gongming,Hou, Tonggang,Zhou, Jianwei,Mu, Xindong
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- Effect of hydrogen donor on liquid phase catalytic transfer hydrogenation of furfural over a Ru/RuO2/C catalyst
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The effect of alcohol hydrogen donor on methyl furan production through catalytic transfer hydrogenation of furfural in the liquid phase has been investigated over a mildly calcined Ru/C catalyst in the temperature range of 110-200 °C. It has been found that several parameters contribute to furfural hydrogenolysis, including alcohol dehydrogenation activity, solvent properties, as well as side reactions such as etherification between the intermediate, furfuryl alcohol, and the hydrogen donor. Methyl furan yield increases from 0 to 68% at 180 °C following the order of 2-methyl-2-butanol tert-butanol ethanol 1-propanol ~ 1-butanol 2-propanol 2-butanol ~ 2-pentanol, which correlates well with the alcohol dehydrogenation activity. In ethanol, 1-propanol, 2-propanol and 2-pentanol, furfuryl alcohol hydrogenolysis to methyl furan is significantly retarded at low temperatures due to furfuryl alcohol etherification with the corresponding alcohol solvent. We find that methyl furan yield decreases with increasing alcohol polarity. An optimum methyl furan yield of 76% is attained after 10 h of reaction at 180 °C, using 2-butanol and 2-pentanol as hydrogen donors. This is the highest reported yield in the liquid phase at temperatures below 200 °C.
- Panagiotopoulou, Paraskevi,Martin, Nickolas,Vlachos, Dionisios G.
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p. 223 - 228
(2014/07/07)
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- Efficient and selective alcoholysis of furfuryl alcohol to alkyl levulinates catalyzed by double SO3H-functionalized ionic liquids
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The production of alkyl levulinates from furfuryl alcohol (FAL) in alcohol media was investigated at moderate temperature in the presence of Bronsted acidic ionic liquids. The reaction was examined and optimized under batch conditions, where it was found that furfuryl alcohol was rapidly and almost quantitatively converted into intermediate products including 2-alkoxymethylfuran and 4,5,5-trialkoxypentan-2-one, and high alkyl levulinates yield of 95% can be achieved after reaching a steady state in 2 h. An advantage of this catalyst system is that undesired dialkyl ether (DEE) formed by a side reaction of the dehydration of alcohol is negligible. The Hammett method was used to determine the acidities of these ionic liquids, which indicated that the acidity and the molecular structure have strong effects on the catalytic activity of ionic liquids. Based on the experimental results, a possible mechanism for the alcoholysis of FAL is proposed.
- Wang, Guofeng,Zhang, Zhanquan,Song, Linhua
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p. 1436 - 1443
(2014/03/21)
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- Action of boron trifluoride etherate and stannic chloride on heterocyclic aromatic acetals
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Twelve heterocyclic aromatic acetals (1a-12a) have been synthesised and their reactions with Lewis acids, viz. boron trifluoride etherate (BTE) and stannic chloride (STC) have been studied.The acetals yield ethers, esters and aldehydes with BTE, but only esters and aldehydes with STC.Interestingly, pyridine-2-aldehyde acetal (12a), yields aldehyde alone, that too in low yield.Probable mechanisms have been suggested for the product formation.
- Raja, S.,Xavier, N.,Arulraj, S. J.
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p. 687 - 689
(2007/10/02)
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- SELECTIVE DESULFURIZATION OF 1,3-DITHIANES, -OXATHIOLANES AND -THIAZOLIDINES BY TRIBUTYLTIN HYDRIDE
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Selective desulfurization of 2-alkyl-1,3-dithianes, -oxathiolanes, or -thiazolidines 1 with one equivalent of tri-n-butyltin hydride yields acyclic compounds R1R2CHX(CH2)nSSnBu3 (X=S,O,NH; n=2,3), (2) which can be destannylated to the corresponding mercaptans 3.
- Schmidt, K.,O'Neal, S.,Chan, T.C.,Alexis, C.P.,Uribe, J.M.,et al.
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p. 7301 - 7304
(2007/10/02)
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- Reactions of Heterocyclic Aromatic Acetals Over γ-Alumina, Aluminium Phosphate and Aluminium Sulphate
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Reactions of twelve heterocyclic aromatic acetals (1a-12a) over solid catalysts such as γ-alumina (AL), aluminium phosphate (AP) and aluminium sulphate (AS) have been studied.The reactions of acetals over AL and AP lead to the corresponding ethers, esters and aldehydes, while over AS the products formed are the corresponding esters and aldehydes.The anomalous behaviour of pyrrole-2-aldehyde acetal (10a) and pyridine-2-aldehyde acetal (12a) over catalysts is of particular interest.Probable mechanisms have been suggested for the reactions.
- Raja, S.,Xavier, N.,Arulraj, S. J.
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p. 916 - 919
(2007/10/02)
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