- Design of a highly ordered mesoporous H3PW12O 40/ZrO2-Si(Ph)Si hybrid catalyst for methyl levulinate synthesis
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A highly ordered mesoporous ZrO2-based material functionalized by benzene-bridged organosilica groups and the Keggin type heteropolyacid, prepared in a single co-condensation-hydrothermal treatment step, exhibited much higher catalytic activity towards methyl levulinate synthesis compared to alkyl-free H3PW12O40/ZrO2.
- Su, Fang,Ma, Ling,Song, Daiyu,Zhang, Xianghuan,Guo, Yihang
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- Conversion of carbohydrate biomass to methyl levulinate with Al 2(SO4)3 as a simple, cheap and efficient catalyst
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Al2(SO4)3 was developed as a simple and efficient catalyst for the synthesis of methyl levulinate (MLE) from carbohydrate biomass including fructose, glucose, mannose, sucrose, cellobiose, starch, and cellulose. The maximum MLE yield of 64% from glucose could be obtained at 160 C for 150 min. Important roles of Al3 + and Br?nsted acid sites generated by the hydrolysis/methanolysis of Al 3 + were elucidated. The reaction process was revealed using in situ real-time attenuated total reflection infrared spectroscopy. Al 2(SO4)3 can be regenerated easily and reused at least four times without the loss of activity.
- Zhou, Lipeng,Zou, Haojie,Nan, Jiaxu,Wu, Lin,Yang, Xiaomei,Su, Yunlai,Lu, Tianliang,Xu, Jie
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- Heteropoly acid and ZrO2 bifunctionalized organosilica hollow nanospheres for esterification and transesterification
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Single-micelle-templated preparation of heteropoly acid and ZrO2 bifunctionalized organosilica hollow nanospheres (H3PW 12O40/ZrO2-Et-HNS) is developed by co-hydrolysis and -condensation of bissilylated organic precursor, 1,2-bis(trimethoxysilyl)ethane (BTMSE), with a zirconium source (Zr(OC 4H9)4) in the presence of H3PW 12O40, triblock copolymer surfactant F127 and 1,3,5-trimethylbenzene (TMB) followed by boiling ethanol washing. Through tuning the molar ratios of Si/Zr in the initial gel mixture, the morphology transformation from the 3D interconnected mesostructure to the hollow spherical nanostructure is realized. The inner diameter of the H3PW 12O40/ZrO2-Et-HNS materials is in the range of 6-12 nm, and their shell thickness is ca. 2 nm. As novel organic-inorganic hybrid catalysts, the catalytic activity of H3PW12O 40/ZrO2-Et-HNS is evaluated by the model reactions of esterification of levulinic acid (LA) with methanol to methyl levulinate and transesterification of yellow horn oil with methanol to biodiesel at refluxing temperature (65 °C) and atmospheric pressure. The obtained excellent heterogeneous acid catalytic activity of H3PW12O 40/ZrO2-Et-HNS is explained in terms of their strong Broensted and Lewis acidity, unique hollow nanospherical morphology and hydrophobic surface. Finally, the recyclability of the hybrid catalysts is tested through three consecutive catalytic runs. This journal is the Partner Organisations 2014.
- Su, Fang,An, Sai,Song, Daiyu,Zhang, Xianghuan,Lu, Bo,Guo, Yihang
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- 1,2-Dioxetanes Derived from 4,5-Dimethyl-2,3-dihydrofuran and 4,5-Dimethyl-2,3-dihydrothiophene: Synthesis via Photooxygenation, Activation Parameters, and Excitation Properties
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Photooxygenation of 4,5-dimethyl-2,3-dihydrofuran (1a) and 4,5-dimethyl-2,3-dihydrothiophene (1b) in a variety of solvents gave the respective 1,2-dioxetanes 2a,b ( cycloaddition) as major products (82-90percent) and the allylic hydroperoxides 3a,b and 4a,b (ene reaction) as minor products (10-18percent).The 2,3-dihydrofuran-derived dioxetane 2a shows higher thermal stability compared to other known alkoxy-substituted dioxetanes; but more remarkable is the 2,3-dihydrothiophene derivative 2b , the most stable sulfur-substituted dioxetane to date, isolable by molecular distillation.Concerning their excitation properties, both dioxetanes afford preferentially triplet excited state products during thermal decomposition, e.g. ΦT = 3.2 +/- 0.5percent for 2a and ΦT ca. 0.002percent for 2b, the latter being the first triplet exitation yield (ΦT) for a sulfur-substituted dioxetane.Mechanistic rationales for the 1000-fold lower efficiency of generating excited states for the 2,3 -dihydrothiophene dioxetane 2b are presented.
- Adam, Waldemar,Griesbeck, Axel G.,Gollnick, Klaus,Knutzen-Mies, Karen
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- Conversion of carbohydrates to methyl levulinate catalyzed by sulfated montmorillonite
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We reported a highly efficient conversion of carbohydrates such as glucose to methyl levulinate (ML) in methanol with a series of sulfated montmorillonite (MMT) as simple and inexpensive catalysts. Among these catalysts, the MMT treated by H2SO4 after calcination (especially the MMT treated by 20% H2SO4) showed a high catalytic activity. Under the optimal conditions, the conversion of glucose and fructose was up to 100%, and the ML yields obtained from glucose and fructose were 48% and 65%, respectively. The reaction conditions were optimized. Further, the structure and properties of sulfated MMT were characterized.
- Xu, Xingliang,Zhang, Xianlong,Zou, Weijian,Yue, Huijuan,Tian, Ge,Feng, Shouhua
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- Acid-catalysed direct transformation of cellulose into methyl glucosides in methanol at moderate temperatures
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Cellulose can be transformed into methyl glucosides in methanol with yields of 50-60% in the presence of several acid catalysts under mild conditions (≤473 K); H3PW12O40 provides the highest turnover number (～73 in 0.5 h)
- Deng, Weiping,Liu, Mi,Zhang, Qinghong,Tan, Xuesong,Wang, Ye
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- One-pot synthesis of dimethyl succinate from D-fructose using Amberlyst-70 catalyst
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Dimethyl succinate (DMS), an important building block of bio-based platform chemicals, was produced from D-fructose under one-pot and metal-free conditions for the first time. In the presence of 1.5 mmol D-fructose, 75 mg Amberlyst-70 and 10 bar O2/
- He, Liangtu,Huang, Yuzhang,Len, Christophe,Liu, Lei,Miao, Xinge,Wang, Yantao,Yang, Weiran
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- Efficient alcoholysis of furfuryl alcohol to n-butyl levulinate catalyzed by 5-sulfosalicylic acid
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It is urgent to study the utilization of biomass energy to solve the environmental problems caused by the excessive use of fossil fuels. In this study, a rapid and efficient route for the conversion of furfuryl alcohol (FA) into n-butyl levulinate (BL) has been catalyzed by 5-sulfosalicylic acid. The nearly complete conversion of FA and a considerable 99.7% selectivity of BL are obtained under the optimal conditions. Based on the experimental results, a possible mechanism for the alcoholysis of FA is proposed. The present study provided a promising way for alkyl levulinates synthesis over economical and environmentally benign catalysts.
- Zhao, Wenguang,Ding, Hui,Tian, Yi,Xu, Qiong,Liu, Xianxiang
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p. 1339 - 1345
(2021/02/26)
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- 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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- Esterification of levulinic acid over Sn(II) exchanged Keggin heteropolyacid salts: An efficient route to obtain bioaditives
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In this paper, we describe a process to add value to the biomass derivatives (i.e., levulinic acid), converting it to bioadditives over solid Sn(II) exchanged Keggin heteropolyacid salts. These solid catalysts are an attractive alternative to the traditional soluble and corrosive Br?nsted acid catalysts. Among Sn(II) heteropoly salts, the Sn1.5PW12O40 was the most active and selective catalyst, achieving high conversions (ca. 90 %) and selectivity (90–97 %) for alkyl esters and angelica lactone, the main reaction products. The impacts of the main reaction parameters (i.e., catalyst load, temperature, and the molar ratio of alcohol to acid) were investigated. The use of renewable raw material, and an efficient and recyclable catalyst are the main positive features of this process. The Sn1.5PW12O40 catalyst was easily recovered and reused without loss activity.
- Da Silva, Márcio José,Chaves, Diego Morais,Teixeira, Milena Galdino,Oliveira Bruziquesi, Carlos Giovani
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- Metal-free reduction of unsaturated carbonyls, quinones, and pyridinium salts with tetrahydroxydiboron/water
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A series of unsaturated carbonyls, quinones, and pyridinium salts have been effectively reduced to the corresponding saturated carbonyls, dihydroxybenzenes, and hydropyridines in moderate to high yields with tetrahydroxydiboron/water as a mild, convenient, and metal-free reduction system. Deuterium-labeling experiments have revealed this protocol to be an exclusive transfer hydrogenation process from water. This journal is
- Li, Tiejun,Peng, Henian,Tang, Wenjun,Tian, Duanshuai,Xu, Guangqing,Yang, He
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p. 4327 - 4337
(2021/05/31)
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- Eco-Friendly Natural Clay: Montmorillonite Modified with Nickel or Ruthenium as an Effective Catalyst in Gamma-Valerolactone Synthesis
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Ni/Ru metals supported on cheap and available support montmorillonite K10 were used for the selective hydrogenation of levulinic acid to γ-valerolactone. Different loadings of the metals were applied by the impregnation method, and detailed characterization was performed (UV–VIS, XRD, TPR, TPD, particle size distribution, SEM, XRF). Metals’ homogeneous distribution on the surface was confirmed. The selectivity to the desired product was almost independent on the used material. A detailed study of the influence of solvents on the studied reaction was also performed—protic alcohol-based solvents caused the formation of levulinic and valeric acid esters in the reaction mixture. The selectivity was influenced mainly by the alcohol structure (the highest selectivity obtained using isopropyl alcohol and sec-butanol). Mainly the solvent’s donor number (except ethanol) influenced the reaction rate. The prepared catalysts are promising, available, and cheap materials for the studied reaction. Solvent may significantly influence the yield of γ-valerolactone. Graphic Abstract: [Figure not available: see fulltext.].
- ?erveny, Libor,Trejbal, Ji?í,Vaňková, Michaela,Vrbková, Eva,Vysko?ilová, Eli?ka
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- Method for preparing alkyl levulinate by regulating water content
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The invention discloses a method for preparing alkyl levulinate by regulating water content. The method comprises the following steps: at least mixing furfuryl alcohol, alkyl alcohol and an acidic catalyst to form a reaction system, carrying out a reaction under the conditions of continuous stirring and reflux condensation, regulating the content of water in the reaction system to enable a mol ratio of the furfuryl alcohol to the water to be 1: (0.1-5), and carrying out aftertreatment to obtain alkyl levulinate. The structural formula of the alkyl levulinate is as shown in the specification. In the structural formula, R is any one selected from the group consisting of -CH3, -C2H5, -C3H7, -C4H9 and -C5H11. Compared with the prior art, the method provided by the invention has the advantagesthat the alkyl levulinate is prepared by regulating the water content; process is simple and feasible; conditions are mild; cost is low; few byproducts are produced; maximum yield reaches 99.8%; and the problem of low yield of alkyl levulinate in conventional synthesis methods is solved.
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Paragraph 0046; 0047; 0064-0067
(2020/04/17)
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- Photoredox-Catalyzed Isomerization of Highly Substituted Allylic Alcohols by C?H Bond Activation
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Photoredox-catalyzed isomerization of γ-carbonyl-substituted allylic alcohols to their corresponding carbonyl compounds was achieved for the first time by C?H bond activation. This catalytic redox-neutral process resulted in the synthesis of 1,4-dicarbonyl compounds. Notably, allylic alcohols bearing tetrasubstituted olefins can also be transformed into their corresponding carbonyl compounds. Density functional theory calculations show that the carbonyl group at the γ-position of allylic alcohols are beneficial to the formation of their corresponding allylic alcohol radicals with high vertical electron affinity, which contributes to the completion of the photoredox catalytic cycle.
- Guo, Kai,Huang, Jun,Li, Anding,Li, Yuanhe,Yang, Zhen,Zhang, Zhongchao
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supporting information
p. 11660 - 11668
(2020/05/25)
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- Importance of the synergistic effects between cobalt sulfate and tetrahydrofuran for selective production of 5-hydroxymethylfurfural from carbohydrates
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In this study, an effective catalytic system (CoSO4·7H2O/THF) for selective conversion of fructose to 5-hydroxymethylfurfural (HMF; yield: 88%) was developed. The synergistic effects among Co2+, SO42-, crystal water and tetrahydrofuran (THF) were crucial for achieving selective dehydration of fructose to HMF. Co2+ worked as a Lewis acid for catalyzing mainly dehydration of fructose to HMF but not the further decomposition of HMF to levulinic acid. THF could help to retain HMF while CoSO4 could coordinate with HMF, enhancing the thermal stability of HMF in THF. The crystal water in cobalt sulfate could help to coordinate with fructose, which facilitated the conversion of fructose via dehydration reactions. The CoSO4·7H2O/THF catalytic system could also catalyze the conversion of inulin and cellulose into HMF. The main advantages of the CoSO4·7H2O/THF catalytic system are the low cost, the easy recycling of the CoSO4·7H2O catalyst and the easy separation of HMF from volatile THF.
- Dong, Dehua,Hu, Xun,Li, Qingyin,Li, Xueli,Shao, Yuewen,Sun, Kai,Wang, Yi,Ye, Zhengmao,Zhang, Lijun,Zhang, Shu
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p. 2293 - 2302
(2020/04/20)
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- Ammonia borane enabled upgrading of biomass derivatives at room temperature
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Simplifying biomass conversion to valuable products with high efficiency is pivotal for the sustainable development of society. Herein, an efficient catalyst-free system using ammonia borane (AB) as the hydrogen donor is described, which enables controllable reaction selectivity towards four value-added products in excellent yield (82-100%) under very mild conditions. In particular, the system is uniquely efficient to produce γ-valerolactone (GVL) at room temperature. Combined in situ NMR and computational studies elucidate the hydrogen transfer mechanism of AB in methanol, the novel pathway of GVL formation from levulinate in water, and a competitive mechanism between reduction and reductive amination in the same system. Moreover, carbohydrates are converted directly into GVL in good yield, using a one-pot, two-step strategy. Products of a rather broad scope are prepared within a short reaction time of 30 min by using this catalyst-free strategy in methanol at room temperature. This journal is
- Meier, Sebastian,Riisager, Anders,Yang, Song,Zhao, Wenfeng
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supporting information
p. 5972 - 5977
(2020/11/03)
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- Microwave-assisted catalytic upgrading of bio-based furfuryl alcohol to alkyl levulinate over commercial non-metal activated carbon
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A cheap and commercially available non-metal activated carbon (AC) as an efficient catalyst for the alcoholysis of furfuryl alcohol (FA) to alkyl levulinate (AL) under microwave assistance was firstly investigated. The catalyst gave an impressive methyl levulinate (ML) yield of 78% in only 5 min at 170 °C in the presence of FA (0.2 M, 3 mL) and AC (100 mg). Various reaction parameters in dependence of time such as temperature, catalyst and feedstock loadings as well as solvent types have been optimized. The re-utilization experiments of the catalyst showed that the activity related to the acidic groups of the catalysts, and the deactivation was due to the leaching of acidic specie, which was easily extracted by the solvent. Note that extremely low concentration of the active species extracted from AC (less than 1 wt %) could also give 62% ML yield. The present study provided a promising way for AL synthesis over cheap, commercially available and environmentally benign catalyst.
- Wang, Yantao,Zhao, Deyang,Triantafyllidis, Konstantinos S.,Ouyang, Weiyi,Luque, Rafael,Len, Christophe
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- Catalytic conversions of isocyanate to urea and glucose to levulinate esters over mesoporous α-Ti(HPO4)2·H2O in green media
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We have described a facile solvothermal synthesis of a sheet-like α-Ti(HPO4)2·H2O nanomaterial. The material comprises 10.7 nm nanoparticles along with ordered mesopores throughout its hexagonal building blocks. The material possesses a bandgap of 3.86 eV and works as an efficient catalyst for the selective synthesis of ureas from a broad range of isocyanates in the presence of H2O at room temperature with a high product yield (up to 93%) and a TOF value up to 15.25 h-1. The α-Ti(HPO4)2·H2O nanomaterial also catalytically converts glucose to levulinic acid (LA) and subsequently LA to alkyl levulinates in the presence of different alcohols with a high product yield (up to 98%) and a TOF value up to 43.00 h-1. Furthermore, all the reactions are performed under green and facile catalytic conditions without using any hazardous solvent. The α-Ti(HPO4)2·H2O catalyst material was also found to be reusable for manifold cycles for all the reactions, keeping its catalytic efficiency along with its structural and morphological characteristics unaffected, supporting its industrial relevance.
- Hazra Chowdhury, Arpita,Hazra Chowdhury, Ipsita,Biswas, Surajit,Chakrabortty, Pekham,Islam, Sk. Manirul
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p. 16452 - 16460
(2020/10/14)
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- Highly ordered mesoporous functionalized pyridinium protic ionic liquids framework as efficient system in esterification reactions for biofuels production
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Polysiloxane acidic ionic liquids containing pyridinium trifluoroacetate salts (PMO-Py-IL) were synthesized from pyridine containing organosilane precursors. Characterization by SEM, XRD, TGA, and nitrogen porosimetry confirmed that both pyridinium cation and trifluoroacetate anion were successfully incorporated within the organosilica network. The resulting organic-inorganic hybrid nanomaterial (PMO-Py-IL) was studied as nanocatalyst in free fatty acids esterification into biodiesel-like compounds. Remarkably, the synergistic hydrophilic/hydrophobic effect of pyridinium and trifluoroacetate ionic liquid in the well-ordered channels of PMO-Py-IL nanomaterial enhanced the activity toward sustainable biodiesel-like esters production. More importantly, PMO-Py-IL nanocatalyst also exhibited an exceptional activity and stability. The catalyst could be easily separated to reuse at least in ten reactions runs preserving almost intact its catalytic activity under otherwise identical conditions to those employed for the fresh catalysts.
- Luque, Rafael,Rajabi, Fatemeh
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- Inexpensive and tuneable protic ionic liquids based on sulfuric acid for the biphasic synthesis of alkyl levulinates
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Alkyl levulinates are bio-derived chemicals, increasingly popular for their uses as solvents, additives and intermediates. However, efficient and recyclable catalysts for their synthesis are still the subject of intensive research. In this study, a wide range of alkyl levulinates was synthesized under mild conditions (room temperature, atmospheric pressure), using inexpensive and efficient Br?nsted acidic ionic liquids (ILs) based on sulfuric acid and off-the-shelf bases. Acidity of the ILs was closely related to their activity. The ILs could be easy separated and recycled, without significant changes in conversion or selectivity over 10 cycles (yields ca. 90–95%). Under optimized conditions, a 99% yield of pentyl levulinate (model reaction) was achieved. The method was demonstrated to be efficient in the synthesis of levulinates of C1-C16 linear, branched and cyclic alcohols. This innovative, green route to alkyl levulinates fits well within the sustainable development strategy.
- Chrobok, Anna,Gillner, Danuta,Matuszek, Karolina,Przypis, Marta,Swad?ba-Kwa?ny, Ma?gorzata
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- Acidic ion functionalized N-doped hollow carbon for esterification of levulinic acid
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Acidic ion functionalized N-doped hollow carbon (NHC-[C4N][SO3CF3]) has been successfully synthesized by quaternization of N-doped hollow carbon (NHC) with 1,4-butanesultone, followed by ion exchange with trifluoromethanesulfonic acid. The catalyst was characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), acid-base titration techniques and other methods. A hollow spherical catalyst with regular morphology, high acid density (2.72 mmol g-1) and good stability was obtained. Various characterizations showed that NHC-[C4N][SO3CF3] possesses abundant nanopores (3.41 nm), large Brunauer-Emmett-Teller (BET) surface area (154 m2 g-1) and strong and controllable Br?nsted acid sites. The as-prepared NHC-[C4N][SO3CF3] was then used for the acid-catalyzed esterification of levulinic acid with ethanol. At the optimum conditions, the highest conversion of levulinic acid reached 94.17% and high conversion was maintained after recycling four times. Further investigation of the catalytic activity in the esterification of different aliphatic and aromatic alcohols with levulinate was carried out, showing good results.
- Zhang, Qifang,Jiang, Pingping,Nie, Zhixin,Zhang, Pingbo
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p. 1588 - 1593
(2020/02/06)
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- A New Sulfonic Acid-Functionalized Organic Polymer Catalyst for the Synthesis of Biomass-Derived Alkyl Levulinates
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Abstract: Alkyl levulinates are important biobased chemicals with great fuel-blending properties and good reactivity. In this work, a new functionalized nitrogen-containing organic polymer bearing sulfonic acid groups (PDVTA-SO3H) was successfully prepared and studied for the esterification of levulinic acid with alcohols to produce alkyl levulinates. The results showed that this sulfonic acid-functionalized organic polymer possessed high catalytic activity, and the yield of n-butyl levulinate reached 97.4% under the mild conditions. PDVTA-SO3H exhibited strong acidic sites and high stability, and would be well expected to be a potential candidate better than some commercial sulfonic solid catalysts for alkyl levulinates production. The catalyst had been reused without any treatment for five times and the results proved its potential for industrial applications. Graphic Abstract: A new sulfonic acid-functionalized organic polymer showed high activity in the conversion of biomass derived levulinic acid into alkyl levulinates.[Figure not available: see fulltext.]
- Tian, Yi,Zhang, Ruoqi,Zhao, Wenguang,Wen, Sha,Xiang, Yanping,Liu, Xianxiang
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p. 3553 - 3560
(2020/05/22)
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- Preparation method of alkyl levulinate under mild conditions
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The invention discloses a preparation method of alkyl levulinate under mild conditions. The preparation method comprises the following steps: uniformly mixing furfuryl alcohol, alkyl alcohol and a solid catalyst, carrying out a reaction under the conditions of continuous stirring and condensation reflux, and carrying out post-treatment to obtain alkyl levulinate, wherein the alkyl levulinate has astructural formula represented by a formula I, and R is selected from any one of -CH3, -C2H5, -C3H7 and -C4H9. Compared with the method in the prior art, the preparation method of the invention is simple and easy to implement, mild in condition and few in by-product, has the yield of alkyl levulinate of up to 99.8%, can directly obtain a pure product, and solves the problem of high temperature condition required for the high yield of alkyl levulinate in the existing synthesis method.
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Paragraph 0043-0046; 0059-0060; 0062-0065
(2020/04/01)
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- A novel Ni/AC catalyst prepared by MOCVD method for hydrogenation of ethyl levulinate to γ-valerolactone
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GVL (γ-valerolactone) is identified as an important biomass platform molecule due to its wide application. In this work, a series of novel supported Ni catalysts with different supports and Ni loading were synthesized via metal-organic chemical vapor deposition (MOCVD) method for the hydrogenation of EL (ethyl levulinate) to GVL. Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), nitrogen adsorption/desorption, inductively coupled plasma optical emission spectroscopy (ICP-OES) and transmission electron microscopy (TEM) were used to characterize the as-synthesized catalysts. The results showed that the 2 wt.% Ni/AC(MOCVD) presented superior catalytic activity when compared with the catalyst prepared by impregnation method. This behavior is explained in terms of the smaller Ni nanoparticles (4.28 nm) and higher dispersion on 2 wt.% Ni/AC(MOCVD). Among the catalysts, the 2 wt.% Ni/AC catalyst exhibited the best catalytic performance with 99.7 % EL conversion and 79.8 % GVL yield under 1 MPa initial H2 pressure (measured at room temperature) at 250 °C for 2 h. In addition, the reaction conditions were optimized and the stability of the catalyst were also investigated. The insights gained from this study in the design of high dispersed Ni particles with smaller particle size via MOCVD method will facilitate the metal-catalyzed hydrogenation of EL to GVL.
- Bao, Jinrong,Diao, Xinyong,Ji, Na,Liu, Qingling,Liu, Zhenyu,Lu, Xuebin,Ma, Degang,Song, Chunfeng,Yu, Zhihao
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- HReO4 as highly efficient and selective catalyst for the conversion of carbohydrates into value added chemicals
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This work describes the first catalyst (HReO4) that promotes the efficient and selective conversion of several carbohydrates into four compounds, ethyl levulinate (EL), 5-ethoxymethylfurfural (EMF), 5-hydroxymethylfurfural (HMF) and levulinic acid (LA), through a one-pot reaction strategy adjusting the reaction conditions. The reaction of fructose in ethanol at 160 °C gave EL in 80% yield after 16 h and in a mixture of ethanol/THF at 140 °C produced EMF in 73% yield after 1 h. HMF and LA can also be obtained selectively with 100% yield from fructose at 140 °C after 1 h, in DMSO or 1,4-dioxane, respectively. EL, HMF, LA and EMF were also produced in moderate to good yields from other carbohydrates such as inulin and sucrose. The catalyst HReO4 can be used in gram scale for the production of EL, EMF, HMF and LA with good yields and in at least 8 catalytic cycles on the conversion of fructose into EL with no significant reduction in its activity.
- Bernardo, Joana R.,Oliveira, M. Concei??o,Fernandes, Ana C.
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- Catalytic conversion of furfuryl alcohol or levulinic acid into alkyl levulinates using a sulfonic acid-functionalized hafnium-based MOF
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Biomass conversion using reusable solid acid catalysts are highly desirable to comply with the principles of green chemistry. Here, we report a sulfonic acid-functionalized hafnium-based metal-organic framework (MOF), UiO-66(Hf)-SO3H, as an efficientsolid acidcatalyst for the alcoholysis of furfuryl alcohol (FA) andesterification of levulinic acid (LA) affording alkyl levulinates (ALs). Among the as prepared UiO-66 based MOFs(UiO-66(Hf), UiO-66(Hf)-NH2, UiO-66(Hf)-SO3H and UiO-66(Zr)-SO3H), UiO-66(Hf)-SO3H holds highest Br?nsted acidity and therefore exhibits excellent catalytic activity towards production of ALs. The highest Br?nsted acidity in UiO-66(Hf)-SO3His the result of the covalently bound sulfonic acid groups present inorganic linkers along with the ligated hydroxyl groups (Hf-μ3-OH) to the Hf metal clusters.
- Gupta, Shyam Sunder R.,Kantam, Mannepalli Lakshmi
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- Simultaneous Conversion of C5 and C6 Sugars into Methyl Levulinate with the Addition of 1,3,5-Trioxane
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The simultaneous conversion of C5 and C6 mixed sugars into methyl levulinate (MLE) has emerged as a versatile strategy to eliminate costly separation steps. However, the traditional upgrading of C5 sugars into MLE is very complex as it requires both acid-catalyzed and hydrogenation processes. This study concerns the development of a one-pot, hydrogenation-free conversion of C5 sugars into MLE over different acid catalysts at near-critical methanol conditions with the help of 1,3,5-trioxane. For the conversion of C5 sugars over zeolites without the addition of 1,3,5-trioxane, the MLE yield is quite low, owing to low hydrogenation activity. The addition of 1,3,5-trioxane significantly boosts the MLE yield by providing an alternative conversion pathway that does not include the hydrogenation step. A direct comparison of the catalytic performance of five different zeolites reveals that Hβ zeolite, which has high densities of both Lewis and Br?nsted acid sites, affords the highest MLE yield. With the addition of 1,3,5-trioxane, the hydroxymethylation of furfural derivative and formaldehyde is a key step. Notably, the simultaneous conversion of C5 and C6 sugars catalyzed by Hβ zeolite can attain an MLE yield as high as 50.4 % when the reaction conditions are fully optimized. Moreover, the Hβ zeolite catalyst can be reused at least five times without significant change in performance.
- Lyu, Xilei,Zhang, Zihao,Okejiri, Francis,Chen, Hao,Xu, Mai,Chen, Xujie,Deng, Shuguang,Lu, Xiuyang
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p. 4400 - 4404
(2019/09/09)
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- Catalytic Transfer Hydrogenation of Biomass-Derived Ethyl Levulinate into Gamma-Valerolactone Over Graphene Oxide-Supported Zirconia Catalysts
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Abstract: The transformation of biomass-derived intermediates into value-added chemicals and liquid fuels is of great importance in sustainable chemistry. In this study, graphene oxide supported ZrO2 (ZrO2/GO) was found to be an active heterogeneous catalyst for the transfer hydrogenation of ethyl levulinate to γ-valerolactone (GVL) with iso-propanol as the hydrogen donor. Several important reaction parameters such as the hydrogen donor, the reaction temperature and the catalyst loading were studied in detail with the aim to get a high yield of GVL. It was found that the structure of alcohols had a great effect towards the activity of the ZrO2/GO catalyst and the selectivity of GVL. Iso-propanol was the best hydrogen donor for the transfer hydrogenation of ethyl levulinate to GVL. The highest GVL yield reached 91.7% with an ethyl levulinate conversion of 96.2% under optimal reaction conditions. More importantly, the ZrO2/GO catalyst demonstrated a high stability without the loss of its catalytic activity during the recycling experiments, which should be due to the strong interaction between GO and ZrO2. Graphical Abstract: The graphene oxide supported ZrO2 (ZrO2/GO) catalyst showed high activity for the transfer hydrogenation of ethyl levulinate to GVL with a high yield up to 91.7%.[Figure not available: see fulltext.].
- Lai, Jinhua,Zhou, Shuolin,Liu, Xianxiang,Yang, Yongjun,Lei, Jing,Xu, Qiong,Yin, Dulin
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p. 2749 - 2757
(2019/09/03)
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- IONIC POLYMERS AND USE THEREOF IN PROCESSING OF BIOMASS
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Ionic polymers (IP) are made of anions and a polymeric backbone containing cations. The ionic polymers are incorporated in membranes or attached to solid supports and use of the ionic polymers in processing of biomass.
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Paragraph 0210-0211
(2019/02/13)
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- Pd-catalysed formation of ester products from cascade reaction of 5-hydroxymethylfurfural with 1-hexene
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A cascade reaction involving decarbonylation of 5-hydroxymethylfurfural (HMF) followed by methoxycarbonylation of 1-hexene produces methyl heptanoate (MH) using a catalytic system composed of a Pd-phosphine complex and methanesulfonic acid (MSA) co-catalyst at moderate reaction temperature. Concomitant hydration of HMF followed by hydrogenation of methyl levulinate (ML) to γ-valerolactone (GVL) occurs with the catalytic system under the same reaction conditions using HMF and methanol as the source of CO and H2, respectively. Under optimized reaction conditions, about 50% of MH along with 12% ML and 35% GVL is obtained from HMF using Pd-(1,2-bis(di-tert-butylphosphinomethyl)benzene) (DTBPMB), MSA and 1-hexene in methanol at 120 °C. Interestingly, sugars, such as glucose, fructose and xylose, are able to be converted to MH, ML and GVL as well. Isotopic labeling studies with 13C1-fructose in methanol-d4 and 13C-methanol-d4 confirm that H2 originates from methanol, while CO generates predominantly from the formyl group of the HMF formed by fructose dehydration.
- Garcia-Suarez, Eduardo J.,Paolicchi, Dario,Li, Hu,He, Jian,Yang, Song,Riisager, Anders,Saravanamurugan, Shunmugavel
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p. 170 - 174
(2018/11/22)
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- Production of lactic acid derivatives from sugars over post-synthesized Sn-Beta zeolite promoted by WO3
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Various metal oxides were used as co-catalysts to improve the production of alkyl lactate over Sn-Beta-P. WO3 exhibited the best promotion effect. The yield of MLA increased from 25% (6.5 g L?1) over Sn-Beta-P (0.2 g) to 52% (13.4 g L?1) over WO3 (0.1 g) and Sn-Beta-P (0.1 g) at 160 °C for 5 h and 3.1 wt% of glucose concentration. MLA yield of 38% was attained even at glucose concentration of 10 wt% and the space-time yield reached 7.1 g L?1 h?1. The action mechanism of WO3 was investigated. Fine WO3 particles adsorbed on surface of Sn-Beta-P in reaction media and decreased the silanol defects of Sn-Beta-P. This promotes retro-aldol of fructose, the rate-determining step of whole reaction, thus facilitated the formation of MLA. Kinetic studies indicate that the presence of WO3 decreased the activation energy of the retro-aldol of fructose. The binary solid WO3 and Sn-Beta-P is recyclable.
- Yang, Xiaomei,Zhang, Yali,Zhou, Lipeng,Gao, Beibei,Lu, Tianliang,Su, Yunlai,Xu, Jie
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p. 285 - 291
(2019/03/21)
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- Novel Cu/Al2O3-ZrO2 composite for selective hydrogenation of levulinic acid to Γ-valerolactone
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Novel Cu/Al2O3-ZrO2 composite catalyst was developed for the catalytic hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) in water. By increasing Al2O3 content of the Cu/Al2O3-ZrO2 composite up to 5.0 wt% resulted in a nearly 3-fold increase in activity, without loss of selectivity towards GVL. This superior catalytic activity can be attributed to the dilution of Cu by Al2O3 as well as the enhanced electronic interaction between Cu and ZrO2 compared to Cu/ZrO2 catalyst. Reusability test for four consecutive runs showed a stable activity and selectivity, thus confirming the scope for practical application.
- He, Daiping,He, Qingqing,Jiang, Ping,Zhou, Gongbing,Hu, Rongqi,Fu, Wensheng
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- A Systematic Study of Metal Triflates in Catalytic Transformations of Glucose in Water and Methanol: Identifying the Interplay of Br?nsted and Lewis Acidity
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The specific type of acidity associated with the given metal trifloromethanesulfonates (Br?nsted or Lewis acidity) dramatically influences the course of reactions, and it is possible to select for disaccharides, fructose, methyl glucosides, or methyl levulinate. Glucose is transformed into a range of value-added molecules in water and methanol under the action of acidic metal triflates as catalysts, including their analogous Br?nsted acid-assisted or Br?nsted base-modified systems. A systematic study is presented of a range of metal triflates in methanol and water, pinning down the preferred conditions to select for each product.
- Bodachivskyi, Iurii,Kuzhiumparambil, Unnikrishnan,Williams, D. Bradley G.
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- An expeditious entry to rare tetrahydroimidazo[1,5-c]pyrrolo[1,2-a]pyrimidin-7(8H)-ones: A single-step gateway synthesis of glochidine congeners
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A single-step gateway synthesis of glochidine and its congeners that possess the rare uncommon tetrahydroimidazo[1,5-c]pyrrolo[1,2-a]pyrimidine core was developed employing histamine and readily available γ-ketoesters. Key features of the developed reaction involve tandem three C–N bonds formation and concomitant annulation of two rings in one pot to access this unique and complex tricyclic structure. Exploration of the unknown bioactivity of these compounds revealed that they elicit antiproliferative activity comparable to the anticancer drug imatinib against 6 cancer cell lines.
- Seo, Jeong Moo,Hassan, Ahmed H.E.,Lee, Yong Sup
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supporting information
(2019/11/26)
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- Zirconium Exchanged Phosphotungstic Acid Catalysts for Esterification of Levulinic Acid to Ethyl Levulinate
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Abstract: Zirconium exchanged phosphotungstic acid catalysts were prepared and studied for esterification of levulinic acid with ethanol. The catalysts were characterized by powder XRD, BET surface area, Raman spectroscopy, FT-infrared spectroscopy, Temperature programmed desorption of NH3 and Pyridine adsorbed FT-IR analysis. The presence of Zr resulted in the generation of strong Lewis acidic sites. Among all the catalysts the catalyst with partially exchanged Zr (Zr0.75TPA) showed higher activity due to the present of stronger Br?nsted and Lewis acidic sites. The Zr0.75TPA catalyst exhibits amazing reusability with constant activity. Graphic Abstract: Zr exchanged TPA is active in the esterification of levulinic acid into ethyl levulinate.[Figure not available: see fulltext.].
- Pasha, Nayeem,Lingaiah,Shiva, Raj
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p. 2500 - 2507
(2019/06/27)
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- Exploring the Br?nsted acidity of UiO-66 (Zr, Ce, Hf) metal-organic frameworks for efficient solketal synthesis from glycerol acetalization
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Zr, Ce, Hf-based isostructural UIO-66 MOFs exhibited varying degree of Br?nsted acidity (UiO-66(Hf) > UiO-66(Ce) > UiO-66(Zr)) on their secondary building units owing to the differences in their oxophilicities. UIO-66(Hf) showed remarkable catalytic activity for solketal synthesis with a turnover frequency as high as 13?886 h?1, which is 90 times higher than that of UiO-66(Zr) and several orders of magnitude higher than that of H2SO4 or Zeolites.
- Bakuru, Vasudeva Rao,Churipard, Sathyapal R.,Maradur, Sanjeev P.,Kalidindi, Suresh Babu
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supporting information
p. 843 - 847
(2019/01/21)
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- Facile and high-yield synthesis of methyl levulinate from cellulose
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Efficient production of chemicals from cellulose provides sustainable routes for the utilization of natural renewable resources to meet the requirements of human society. Herein, we reported a highly efficient and simple metal salt catalyst, Al2(SO4)3, for cellulose conversion to methyl levulinate (ML) under microwave conditions. A highest ML yield of 70.6% was obtained at 180 °C within a very short time of 40 min. The introduction of water could reduce humin/coke formation and solvent consumption, and could also switch the reaction pathway via the more reactive intermediate glucose. Kinetic and mechanistic studies of the subreactions showed that both cellulose hydrolysis and alcoholysis pathways were involved in the cellulose conversion to ML, with the former as the main route in the presence of water. The Lewis acid species [Al(OH)x(H2O)y]n+ and the Br?nsted acid species H+, generated by in situ hydrolysis of Al2(SO4)3, were responsible for the reaction conversions. The reaction with microwave heating showed accelerated reaction rates of 25 times the reaction with conventional oil heating, and even more times for the rates of glucose and methyl glucoside (MG) dehydration, resulting in higher reaction selectivity toward ML production. The catalyst was also successfully recycled and applied to the conversion of cellulose to other alkyl levulinates, as well as the conversion of raw biomass to ML with high yields. The homogeneous nature of Al2(SO4)3, together with its high efficiency and excellent recyclability, make it a potential catalyst for the large-scale production of ML in industry.
- Huang, Yao-Bing,Yang, Tao,Lin, Yu-Ting,Zhu, Ying-Zhi,Li, Li-Cheng,Pan, Hui
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supporting information
p. 1323 - 1334
(2018/03/26)
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- Simple and efficient conversion of cellulose to γ-valerolactone through an integrated alcoholysis/transfer hydrogenation system using Ru and aluminium sulfate catalysts
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The direct conversion of cellulose to specific chemicals represents an important but challenging area that attracts much attention. In this study, we report, for the first time, a one-step conversion of cellulose to γ-valerolactone (GVL), a platform molecule with multiple applications, by integrating alcoholysis and transfer hydrogenation systems over mixed metal salt and Ru catalysts without external hydrogenation. A maximum GVL yield of 51.2% was obtained at 180 °C for 70 min reaction time with microwave heating. The metal salt effectively catalyzed cellulose alcoholysis to generate levulinate in isopropanol, which was also the hydrogen donor for the subsequent catalytic transfer hydrogenation of levulinate to GVL over the Ru/ZrO2 catalyst. It was found that the types of metal center and support material had a significant influence on the reactivity of the catalyst for the catalytic transfer hydrogenation (CTH) reaction, i.e., concerning the existence of sulfuric acid species and water in the reaction system. Microwave heating was demonstrated to be an effective method for cellulose-to-GVL conversion as compared to conventional oil heating, through drastically reducing the reaction time and avoiding decomposition of the reagents. The catalysts were successfully recycled and reused with high reactivity. Finally, the system was also applied to the synthesis of GVL from real biomass, demonstrating the high applicability and potential of the catalytic system for industrial production.
- Huang, Yao-Bing,Yang, Tao,Luo, Yu-Jia,Liu, An-Feng,Zhou, Yi-Han,Pan, Hui,Wang, Fei
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p. 6252 - 6262
(2018/12/04)
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- Preparation method of methyl levulinate by ion liquid catalysis
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The invention discloses a preparation method of methyl levulinate by ion liquid catalysis. The method is characterized in that furfuryl alcohol, glucose, sucrose and the like are used as raw materials; imidazole ion liquid and SnCl4.5H2O are used as catalysts; methanol is used as a raw material and a reaction medium; under the heating condition, a target compound is prepared. The method has the advantages that (1) the used raw materials are renewable resources and conform to the circulation economy development trends; (2) the sources of all raw and auxiliary materials are wide; the preparationis convenient; the cooperated effects of the catalyst are good; the raw material conversion rate is high; the product selectivity is high; (3) the preparation process has low requirements on equipment; the reaction is performed at the normal pressure; the post treatment is convenient; the method is a clean preparation method of the methyl levulinate, and is favorable for scaled industrial development.
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Paragraph 0034; 0035; 0037; 0039
(2018/07/30)
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- Continuous Synthesis of Fuel Additives Alkyl Levulinates via Alcoholysis of Furfuryl Alcohol over Silica Supported Metal Oxides
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Abstract: Aiming at synthesizing alkyl levulinates via alcoholysis of furfuryl alcohol in continuous mode for the first time an attempt is made using cheapest and eco-friendly solid acid catalysts. Different silica supported solid acid catalysts containing the oxides of aluminium, tungsten, zirconium and titanium have been prepared. The nature, number and strength of surface acidic sites were evaluated by DRIFT spectroscopy with pyridine adsorption and NH3-TPD and also structural and textural features of the catalysts have been investigated by XRD and BET surface area techniques. Al2O3/SiO2 catalyst exhibited better activity with 100% conversion of furfuryl alcohol and 92.8% selectivity of methyl levulinate, which may be due to more number of surface acidic sites with large number of weak Lewis acidic sites. The catalytic activity of these solid acid catalysts is as follows: Al2O3/SiO2 > ZrO2/SiO2 > WO3/SiO2 > TiO2/SiO2. This is well correlated with the number of surface acidic sites. The stable catalytic activity during the 10?h time-on-stream study confirmed the sturdiness of Al2O3/SiO2 catalyst and also it is active for the selective formation of ethyl, n-propyl, n-butyl levulinates.
- Chada, Raji Reddy,Koppadi, Kumara Swamy,Enumula, Siva Sankar,Kondeboina, Murali,Kamaraju, Seetha Rama Rao,Burri, David Raju
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p. 1731 - 1738
(2018/04/05)
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- Synergistic Production of Methyl Lactate from Carbohydrates Using an Ionic Liquid Functionalized Sn-Containing Catalyst
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Considerable progress has been made recently in the catalytic conversion of renewable biomass resources to methyl lactate (MLA). However, conceiving eco-friendly and effective catalytic systems for the production of MLA from biomass carbohydrates remains a key challenge. Herein, we report a multifunctional catalyst Sn(salen)/IL, consisting of a Sn(salen) complex and an imidazolium-based ionic liquid (IL), which acts via an intramolecular synergistic effect to convert carbohydrates to MLA in methanol. The versatile properties of the resultant catalyst were revealed to be responsible for the conversion of fructose to MLA and the efficient suppression of undesired side reactions. This catalyst displayed outstanding catalytic activity, high selectivity, and excellent recyclability, giving an MLA yield of up to 68.9 % at 160 °C after 2 h. The results of this study will contribute to new approaches for designing synergistic catalysts for producing liquid fuels and chemicals from biomass resources.
- Wang, Fenfen,Wen, Yi,Fang, Yanxiong,Ji, Hongbing
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p. 4154 - 4161
(2018/09/06)
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- Method for preparing methyl levulinate by means of simultaneous conversion, catalyzed by molecular sieve, of five-member sugar and six-member sugar as well as enhancement of polyformaldehyde in near critical methanol
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The invention discloses a method for preparing methyl levulinate by means of simultaneous conversion, catalyzed by a molecular sieve, of five-member sugar and six-member sugar as well as enhancement of polyformaldehyde in near critical methanol. The method comprises the following steps: (1) adding methanol into a high-temperature and high-pressure reaction kettle with a stirring function, and thenadding the five-member sugar, the six-member sugar, the polyformaldehyde and a molecular sieve based catalyst; (2) stirring, heating up to 130-230 DEG C, and carrying out a reaction for 10min-30h inthe near critical methanol; (3) after the reaction is finished, cooling to room temperature and then filtering, and carrying out rectification on filtrate, thus obtaining a methyl levulinate product at the bottom of a tower, and obtaining recyclable methanol on the top of the tower; carrying out catalyst regeneration on filter residue, and then recycling. The method proves that that the polyformaldehyde can greatly improve the yield of the methyl levulinate prepared by means of the simultaneous conversion, catalyzed by the molecular sieve, of the five-member sugar and the six-member sugar in the near critical methanol; the method has the advantages of environment friendliness, simple process, low cost and no need of high-energy density hydrogen, thus having good industrial application prospect.
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Paragraph 0141; 0142; 0144; 0150
(2018/05/16)
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- Enzymatic Formation of a Skipped Methyl-Substituted Octaprenyl Side Chain of Longestin (KS-505a): Involvement of Homo-IPP as a Common Extender Unit
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Longestin (KS-505a), a specific inhibitor of phosphodiesterase, is a meroterpenoid that consists of a unique octacyclic terpene skeleton with branched methyl groups at unusual positions (C1 and C12). Biochemical analysis of Lon23, a methyltransferase involved in the biosynthesis of longestin, demonstrated that it methylates homoisopentenyl diphosphate (homo-IPP) to afford (3Z)-3-methyl IPP. This compound, along with IPP, is selectively accepted as extender units by Lon22, a geranylgeranyl diphosphate (GGPP) synthase homologue, to yield dimethylated GGPP (dmGGPP). The absolute configuration of dmGGPP was determined to be (4R,12R) by degradation and chiral GC analysis. These findings allowed us to propose an enzymatic sequence for key steps of the biosynthetic pathway of the unusual homoterpenoid longestin.
- Ozaki, Taro,Shinde, Sandip S.,Gao, Lei,Okuizumi, Ryo,Liu, Chengwei,Ogasawara, Yasushi,Lei, Xiaoguang,Dairi, Tohru,Minami, Atsushi,Oikawa, Hideaki
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supporting information
p. 6629 - 6632
(2018/05/03)
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- Phosphotungstic acid heterogenized by assembly with pyridines for efficient catalytic conversion of fructose to methyl levulinate
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Solid acid-catalyzed sugar degradation has been considered to be an efficient approach to synthesize alkyl levulinates (which can be used as fuel additives and surfactants). However, those catalytic processes typically involve harsh reaction conditions and high cost for catalyst preparation. We prepared a series of phosphotungstic acid organic hybrids by a simple solvothermal method, and used them as heterogeneous catalysts for the selective degradation of fructose to methyl levulinate (ML) in methanol with high efficiency under mild reaction conditions. The catalysts were characterized systematically, and the effects of different substituents in pyridine, reaction temperature/time, catalyst dose, and fructose concentration studied. The 3-FPYPW hybrid prepared from 3-fluoropyridine and phosphotungstic acid exhibited superior catalytic activity for the synthesis of ML (82.5%) from fructose (97.8%). A possible reaction pathway was proposed. In addition, the catalyst could be separated from the reaction mixture readily, and reused without remarkable loss of reactivity.
- Fang, Chengjiang,Li, Yan,Zhao, Wenfeng,Wu, Weibo,Li, Hu,He, Chao,Yang, Song
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p. 16585 - 16592
(2018/05/23)
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- Highly Efficient Hydrogenation of Levulinic Acid into Γ-Valerolactone using an Iron Pincer Complex
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The search for nonprecious-metal-based catalysts for the synthesis of γ-valerolactone (GVL) through hydrogenation of levulinic acid and its derivatives in an efficient fashion is of great interest and importance, as GVL is an important a sustainable liquid. We herein report a pincer iron complex that can efficiently catalyze the hydrogenation of levulinic acid and methyl levulinate into GVL, achieving a turnover number of up to 23 000 and a turnover frequency of 1917 h?1. This iron-based catalyst also enabled the formation of GVL from various biomass-derived carbohydrates in aqueous solution, thus paving a new way toward a renewable chemical industry.
- Yi, Yuxuan,Liu, Huiying,Xiao, Ling-Ping,Wang, Bo,Song, Guoyong
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p. 1474 - 1478
(2018/04/25)
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- Protection of COOH and OH groups in acid, base and salt free reactions
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We report an iron-catalyzed general functional group protection method with inexpensive reagents. This environmentally benign process does not use acids or bases, and does not produce waste products. Further purification beyond filtration and evaporation is, in most cases, unnecessary. Free COOH and OH groups can be protected in a one-pot reaction.
- Zhu, Xiaotao,Qian, Bo,Wei, Rongbiao,Huang, Jian-Dong,Bao, Hongli
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supporting information
p. 1444 - 1447
(2018/04/12)
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- Guiding a divergent reaction by photochemical control: Bichromatic selective access to levulinates and butenolides
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Allylic and acrylic substrates may be efficiently transformed by a sequential bichromatic photochemical process into derivatives of levulinates or butenolides with high selectivity when phenanthrene is used as a regulator. Thus, UV-A photoinduced cross-metathesis (CM) couples the acrylic and allylic counterparts and subsequent UV-C irradiation initiates E-Z isomerization of the carbon-carbon double bond, followed by one of two competing processes; namely, cyclization by transesterification or a 1,5-H shift and tautomerization. Quantum chemical calculations demonstrate that intermediates are strongly blue-shifted for the cyclization while red-shifted for the 1,5-H shift reaction. Hence, delaying the double bond migration by employing UV-C absorbing phenanthrene, results in a selective novel divergent all-photochemical pathway for the synthesis of fundamental structural motifs of ubiquitous natural products.
- Sutar, Revannath L.,Sen, Saumik,Eivgi, Or,Segalovich, Gal,Schapiro, Igor,Reany, Ofer,Lemcoff, N. Gabriel
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p. 1368 - 1374
(2018/02/09)
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- Selective Levulinic Acid Hydrogenation in the Presence of Hybrid Dendrimer-Based Catalysts. Part I: Monometallic
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Hybrid Ru-containing catalysts, based on poly(propylene imine) (PPI) dendrimers, immobilized in silica pores, were synthesized and characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The synthesized Ru catalysts proved their efficiency in the selective hydrogenation of levulinic acid and its esters at 80 °C, 30 bar of H2, and 50 % volume substrate concentration in water. Quantitative yields of γ-valerolactone were obtained for both micro- and mesoporous Ru catalysts within 2 h with catalytic activity as high as 1610 h?1. The reaction rate and selectivity on γ-valerolactone were found to depend on several factors such as carrier structure, temperature, presence of water, and substrate/Ru ratio. The novelty of these hybrid materials is the presence of both weak acid (SiO2) and organic base centers (dendrimer amino groups), enhancing the dispersion of Ru nanoparticles. The presence of amino groups in the catalyst stabilizes the Ru nanoparticles during the synthesis and promotes the adsorption of levulinic acid on the surface of Ru nanoparticles during the reaction. Synthesized hybrid Ru catalysts can be reused several times without significant loss of activity.
- Maximov, Anton L.,Zolotukhina, Anna V.,Mamedli, Adila A.,Kulikov, Leonid A.,Karakhanov, Edward A.
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p. 222 - 233
(2017/11/27)
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- Porous iron-phosphonate nanomaterial as an efficient catalyst for the CO2 fixation at atmospheric pressure and esterification of biomass-derived levulinic acid
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Chemical fixation of CO2 and synthesis of biofuels through convenient reaction pathways are very demanding in the context of sustainable and eco-friendly catalysis. Herein, we report the synthesis of iron-phosphonate nanoparticles HPFP-1(NP) through the simple chemical reaction between hexamethylenediamine-N,N,N′,N′-tetrakis-(methylphosphonic acid) and FeCl3 under hydrothermal conditions. The material has been characterized by transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), N2 adsorption/desorption studies and FE-SEM. This porous material showed high catalytic activity for the synthesis of organic carbonates from a wide range of epoxides at room temperature in the presence of CO2 at atmospheric pressure. This nanocatalyst also exhibited excellent catalytic activity for the conversion of levulinic acid into alkyl levulinates. The HPFP-1(NP) catalyst showed high recycling efficiency in these catalytic reactions.
- Ghosh, Swarbhanu,Bhanja, Piyali,Salam, Noor,Khatun, Resmin,Bhaumik, Asim,Islam, Sk. Manirul
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p. 253 - 262
(2017/09/30)
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- Method for synthesizing levulinate
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The invention relates to a method for synthesizing levulinate. The method comprises the following step: catalyzing levulinic acid and alcohol to be subjected to esterification reaction by utilizing aloading type PDA-SO3H solid acid catalyst, so as to obtain the levulinate. According to the method provided by the invention, the loading type PDA-SO3H solid acid catalyst is used as the catalyst, canbe recycled and also can be used for more efficiently catalyzing the generation of the levulinate. The method directly takes the levulinic acid and the alcohol as raw materials and the levulinate issynthesized through one-step reaction; the selectivity of a product is higher than 99.9 percent and the yield is high; when the alcohol is enough, the conversion rate of the levulinic acid reaches 87percent or more.
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Paragraph 0082-0084
(2018/12/02)
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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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- METHOD FOR PRODUCING LEVULINIC ACID ESTER
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Provided is a method for efficiently producing a levulinic acid ester from a cellulose-containing raw material or a carbohydrate-containing raw material in an alcohol solvent using an inexpensive, easily available catalytic system. In a method for producing a levulinic acid ester by reacting at least one of a cellulose-containing raw material and a carbohydrate-containing raw material in the presence of an alcohol and a catalyst, use is made of, as a catalyst, a combination of: at least one metal compound (exclusive of gallium acetylacetonate and indium acetylacetonate) selected from the group consisting of hydroxide salts, sulfates, nitrates, carboxylates, alkoxides, acetylacetonates, and oxides of at least one metal selected from the group consisting of metals belonging to Group XIII and Group XIV of the Periodic Table; and an organic sulfonic acid.
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Paragraph 0047
(2017/12/07)
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- Method for synthesizing acetyl propionate by catalyzing alcoholysis of biomass carbohydrate through microwave assistance in presence of phosphotungstic acid and phosphowolframate
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The invention discloses a method for synthesizing acetyl propionate by catalyzing alcoholysis of biomass carbohydrate through microwave assistance in the presence of phosphotungstic acid and phosphowolframate. The method comprises the step of allowing biomass carbohydrate and alcohol to react under the conditions of microwave assistance and a catalyst, so as to obtain acetyl propionate, wherein the catalyst is phosphotungstic acid or a phosphowolframate, phosphowolframate is any one of aluminum phosphowolframate, iron phosphowolframate, indium phosphowolframate and chromium phosphowolframate, and the use amount of the catalyst is 0.1mmol/15g-0.5mmol/15g of alcohol. The method for preparing acetyl propionate by catalyzing biomass carbohydrate through microwave assistance in the presence of phosphotungstic acid and phosphowolframate has the beneficial effects that the process is simple, reaction conditions are mild, the reaction time is short, the energy consumption can be reduced, and the yield of acetyl propionate is high; and the used catalyst is easy to prepare, has wide applicability to the raw materials, can be repeatedly used, and the catalytic activity of the catalyst is not obviously decreased.
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Paragraph 0051; 0052; 0055; 0056
(2017/10/07)
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- Direct conversion of cellulose to high-yield methyl lactate over Ga-doped Zn/H-nanozeolite Y catalysts in supercritical methanol
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For realizing sustainable bio-based refineries, it is crucial to obtain high yields of value-added chemicals via the direct conversion of cellulose and lignocellulosic biomass. Although the conversion of cellulose using homogeneous catalysts has been demonstrated to be quite successful, low cellulose conversion and poor product selectivity have been observed using heterogeneous catalysts. In this study, for the first time, the efficient conversion of cellulose to lactic acid derivatives, which can be used as a green solvent and a potential precursor for fine chemicals and biodegradable polymers, over a Ga-doped Zn/H-nanozeolite Y (Ga-doped Zn/HNZY) catalyst is described. Under optimized conditions at 280°C in supercritical methanol, methyl lactate (ML) and methyl 2-methoxypropionate (MMP) are obtained in yields of 57.8% and 12.8%, respectively, from cellulose; these values are greater than those reported in previous studies conducted using heterogeneous catalysts. Using oakwood, ML and MMP are obtained in yields of 12.3% and 18.6%, respectively. A large external surface area of the HNZY support and the synergistic effect of Ga doping on ZnO enhance Lewis acid sites with the simultaneous decrease of the Br?nsted acid sites. This unique catalyst (Ga-doped Zn/HNZY) is beneficial for controlling the consecutive reaction pathways of the decomposition of cellulose to glucose, retro-aldol condensation to trioses, and intramolecular Cannizzaro reaction to ML.
- Verma, Deepak,Insyani, Rizki,Suh, Young-Woong,Kim, Seung Min,Kim, Seok Ki,Kim, Jaehoon
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supporting information
p. 1969 - 1982
(2017/06/09)
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- One-pot conversion of biomass-derived xylose and furfural into levulinate esters via acid catalysis
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Direct conversion of biomass-derived xylose and furfural into levulinic acid, a platform molecule, via acid-catalysis has been accomplished for the first time in dimethoxymethane/methanol. Dimethoxymethane acted as an electrophile to transform furfural into 5-hydroxymethylfurfural (HMF). Methanol suppressed both the polymerisation of the sugars/furans and the Aldol condensation of levulinic acid/ester.
- Hu, Xun,Jiang, Shengjuan,Wu, Liping,Wang, Shuai,Li, Chun-Zhu
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supporting information
p. 2938 - 2941
(2017/03/15)
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- Chemocatalytic Conversion of Cellulosic Biomass to Methyl Glycolate, Ethylene Glycol, and Ethanol
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Production of chemicals and fuels from renewable cellulosic biomass is important for the creation of a sustainable society, and it critically relies on the development of new and efficient transformation routes starting from cellulose. Here, a chemocatalytic conversion route from cellulosic biomass to methyl glycolate (MG), ethylene glycol (EG), and ethanol (EtOH) is reported. By using a tungsten-based catalyst, cellulose is converted into MG with a yield as high as 57.7 C % in a one-pot reaction in methanol at 240 °C and 1 MPa O2, and the obtained MG can be easily separated by distillation. Afterwards, it can be nearly quantitatively converted to EG at 200 °C and to EtOH at 280 °C with a selectivity of 50 % through hydrogenation over a Cu/SiO2 catalyst. By this approach, the fine chemical MG, the bulk chemical EG, and the fuel additive EtOH can all be efficiently produced from renewable cellulosic materials, thus providing a new pathway towards mitigating the dependence on fossil resources.
- Xu, Gang,Wang, Aiqin,Pang, Jifeng,Zhao, Xiaochen,Xu, Jinming,Lei, Nian,Wang, Jia,Zheng, Mingyuan,Yin, Jianzhong,Zhang, Tao
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p. 1390 - 1394
(2017/04/14)
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