- Selective esterification of glycerol to bioadditives over heteropoly tungstate supported on Cs-containing zirconia catalysts
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Esterification of glycerol with acetic acid was carried out over tungstophosphoric acid (TPA) supported on Cs-containing zirconia. The catalysts were prepared by impregnation method and characterized by FT-infrared spectroscopy, X-ray diffraction and temperature program desorption of NH 3. The catalysts exhibited more than 90% conversion within a short reaction time. The catalytic activity depends on the amount of exchangeable Cs with TPA on zirconia, which is in tern related to the acidity of the catalysts. The acidity of the catalysts varied with the presence of residual protons of TPA. The effects of various parameters, such as reaction temperature, catalyst concentration and molar ratio of glycerol to acetic acid, were studied and optimized reaction conditions are established.
- Jagadeeswaraiah,Balaraju,Prasad, P.S. Sai,Lingaiah
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- Catalytic hydrogenolysis of glycerol into propyl acetate with ruthenium complexes
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Ru complexes have been utilized as catalyst precursors for glycerol hydrogenolysis under mild conditions, which gave propyl acetate (PA) as a major product. Notably, the esterification reaction of acetic acid with glycerol can prevent glycerol from polymerization. In(OTf)3 played a critical role in facilitating esterification of glycerol and sequential dehydration, while the Ru complexes' function was hydrogenation. The promoter (FeCl3) can suppress the reduction of Ru complex to Ru particles, improving the catalytic performance. The present catalytic system can give full glycerol conversion and 57% yield of PA. Finally, the reaction pathway was proposed accordingly.
- Xu, Zichen,Gong, Honghui,Chen, Manyu,Luo, Ruihan,Qian, Wei,Peng, Qingpo,Hou, Zhenshan
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- Synthesis of Triacetin and Evaluation on Motor
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Triacetin (or glycerol triacetate) was obtained by acetylating the glycerol by-product of biodiesel production process. This procedure is an interesting alternative that follows the principles of green chemistry. In this work, triacetin was synthesized using reactions between glycerol and acetic acid, as well as glycerol and acetic anhydride, using homogeneous and heterogeneous acid catalysis. The goal is to use this product as an additive for biodiesel produced from palm oil, which is a fuel with physical properties that require improvement. The products were characterized by Fourier transform infrared spectroscopy (FTIR), 13C nuclear magnetic resonance (NMR) and gas chromatography (GC). The reaction between glycerol and acetic anhydride was the most effective for obtaining the desired product, with an approximate selectivity of 98percent for triacetin. The triacetin was added to diesel fuel oil and biodiesel in proportions from 5 to 10percent v/v, and the mixtures were tested in an electrical generator. In the test, the engine showed no problems during operation, and incorporating the mixtures did not result in significant consumption. Small reductions were detected in CO, O2 and opacity, but no changes were observed in the emissions of NOx and CO2.
- Lacerda, Claudia V.,Carvalho, Maria J.S.,Ratton, Alice R.,Soares, Itania P.,Borges, Luiz E.P.
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- Optimization of N-methyl-N-[tert-butyldimethylsilyl]- trifluoroacetamide as a derivatization agent for determining isotopic enrichment of glycerol in very-low density lipoproteins
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Stable isotope kinetic studies play an important role in the study of very-low density lipoprotein (VLDL) metabolism, including basic and clinical research. Today, [1,1,2,3,3-2H5]glycerol is the most cost-effective alternative to measure glycerol and triglyceride kinetics. Recycling of glycerol from glycolysis and gluconeogenesis may lead to incompletely labelled tracer molecules. Many existing methods for the measurement of glycerol isotopic enrichment involve the production of glycerol derivatives that result in fragmentation of the glycerol molecule after ionization. It would be favourable to measure the intact tracer molecule since incompletely labelled tracer molecules may be measured as fully labelled. The number of methods available to measure the intact tracer in biological samples is limited. The aim of this project was to develop a gas chromatography/mass spectrometry (GC/MS) method for glycerol enrichment that measures the intact glycerol backbone and is suitable for electron ionization (EI), which is widely available. A previously published method for N-methyl-N-[tert-butyldimethylsilyl]trifluoroacetamide (MTBSTFA) derivatization was signifi-cantly improved; we produced a stable derivative and increased recovery 27-fold in standards. We used the optimized MTBSTFA method in VLDL-triglyceride and found that further modification was required to take matrix effects into account. We now have a robust method to measure glycerol isotopic enrichment by GC/EI-MS that can be used to rule out the known problem of tracer recycling in studies of VLDL kinetics. John Wiley & Sons, Ltd.
- Adiels, Martin,Larsson, Thomas,Sutton, Pauline,Taskinen, Marja-Riitta,Boren, Jan,Fielding, Barbara A.
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- An efficient and sustainable production of triacetin from the acetylation of glycerol using magnetic solid acid catalysts under mild conditions
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The efficient and selective acetylation of glycerol to produce triacetin is achieved using magnetic solid acids as catalysts. The Fe-based materials including Fe-Sn-Ti (OH)x, Fe-Sn-Ti(SO42-) and Fe-Sn-Ti(SO42-)-t (t represents the temperature for the heating treatment) were successfully prepared and employed in the acetylation of glycerol, respectively. As a result, 100% conversion and 99.0% selectivity for triacetin was obtained in the presence of a catalytic amount of Fe-Sn-Ti(SO42-)-400 at 80 °C for 30 min, which exhibits higher catalytic activity than those of some molecular sieves. The magnetic catalytic materials were respectively characterized by XRD, IR, TG-DTG, BET and NH3-TPD techniques. Moreover, the effects of reaction temperature and reaction time in the glycerol acetylation are investigated in detail. Finally, based on the experimental results and reaction phenomena, a possible mechanism for the catalytic reaction is proposed.
- Sun, Jinyan,Tong, Xinli,Yu, Linhao,Wan, Jun
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- Alternative carbon based acid catalyst for selective esterification of glycerol to acetylglycerols
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Carbon-based acid catalysts with porous structure were prepared by sulfonation of carbonized sucrose. The catalysts have an amorphous porous structure with a good acid capacity and high thermal stability. The catalytic activity was evaluated by the esterification of glycerol with acetic acid. The sulfonated carbon catalysts showed that glycerol was completely transformed into a mixture of glycerol esters including a high selectivity of about 50% to triacetylglycerol (TAG).
- Sánchez, Julián A.,Hernández, Diana L.,Moreno, Jorge A.,Mondragón, Fanor,Fernández, Jhon J.
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- Synthesis of bio-additives: Acetylation of glycerol over zirconia-based solid acid catalysts
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Acetylation of glycerol with acetic acid was investigated over ZrO 2, TiO2-ZrO2, WOx/TiO 2-ZrO2 and MoOx/TiO2-ZrO2 solid acid catalysts to synthesize monoacetin, diacetin and triacetin having interesting applications as bio-additives for petroleum fuels. The prepared catalysts were characterized by means of XRD, BET surface area, ammonia-TPD and FT-Raman techniques. The effect of various parameters such as reaction temperature, molar ratio of acetic acid to glycerol, catalyst wt.% and time-on-stream were studied to optimize the reaction conditions. Among various catalysts investigated, the MoOx/TiO2-ZrO2 combination exhibited highest conversion ( ～ 100%) with best product selectivity, and a high time-on-stream stability.
- Reddy, Padigapati S.,Sudarsanam, Putla,Raju, Gangadhara,Reddy, Benjaram M.
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- Design of a highly active silver-exchanged phosphotungstic acid catalyst for glycerol esterification with acetic acid
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A series of highly active, selective, and stable silver-exchanged phosphotungstic acid (AgPW) catalysts were prepared, characterized, and evaluated for bio-derived glycerol esterification with acetic acid to produce valuable biofuel additives. The structures, morphologies, acidities, and water tolerance of these samples were determined by FTIR, Raman, XRD, SEM-EDX, FT-IR of pyridine adsorption, and H2O-TPD. Several typical acidic catalysts were also performed for comparison. Among them, partially silver-exchanged phosphotungstic acid (Ag1PW) presented exceptionally high activity, with 96.8% conversion within just 15 min of reaction time and remarkable stability, due to the unique Keggin structure, high acidity as well as outstanding water-tolerance property. A plausible reaction mechanism was also proposed. In addition, this Ag1PW catalyst exhibited universal significance for esterification, holding great potential for a wide range of other acid-catalyzed reactions.
- Zhu, Shanhui,Gao, Xiaoqing,Dong, Fang,Zhu, Yulei,Zheng, Hongyan,Li, Yongwang
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- SO42-/SnO2: Efficient, chemoselective, and reusable catalyst for acylation of alcohols, phenols, and amines at room temperature
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SO42-/SnO2 was employed for the acylation of a variety of alcohols, phenols, and amines under solvent-free conditions at room temperature. This method showed preferential selectivity for acetylation of the amino group in the presence of a hydroxyl group. The reported method is simple, mild, and environmentally viable, using several other acid anhydrides at room temperature. Copyright Taylor & Francis Group, LLC.
- Satam, Jitendra R.,Gawande, Manoj B.,Deshpande, Sameer S.,Jayaram, Radha V.
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- Heteropolyanion-based ionic liquids: Reaction-induced self-separation catalysts for esterification
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(Figure Presented) It comes out in the wash: In the esterification of citric acid with n-butanol, heteropolyanion-based ionic liquid (IL) catalysts show high catalytic activity, self-separation, and easy reuse. The good solubility in reactants, nonmiscibility with ester product, and high melting point of the IL catalysts enable the reaction-induced switching from homogeneous (b in the picture) to heterogeneous (c) with subsequent precipitation of the catalyst (d).
- Leng, Yan,Wang, Jun,Zhu, Dunru,Ren, Xiaoqian,Ge, Hanqing,Shen, Lei
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- Metabolic engineering of: Escherichia coli for production of non-natural acetins from glycerol
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Mono-, di- and triacetin are three glycerol esters which are usually synthesized via costly and environmentally unfriendly chemical synthesis methods. Here, Escherichia coli is metabolically engineered for the production of mono-, di- and triacetin using glycerol as a substrate. First, a novel biosynthetic route of mono- and diacetin is established by overexpression of a native enzyme, maltose O-acetyltransferase (MAA). Next, the biosynthetic pathway is extended to produce a mixture of mono-, di- and triacetin by overexpression of chloramphenicol-O-acetyltransferase (CAT). By successive strategies, including heterologous gene expression, metabolic engineering, and culture optimization, a recombinant E. coli is enabled to produce more than 27 g L-1 of a mixture of mono-, di- and triacetin in shake flask cultures, which is a >650-fold increase over the initial production of 0.04 g L-1. In vitro studies confirm the acetylation of glycerol to mono- and diacetin by MAA, and the additional acetylation to triacetin by CAT. When crude glycerol is used as a substrate, the engineered strain produced a total of 25.9 g L-1 of the acetin mixture, about the same as that achieved from pure glycerol. To our knowledge, this is the first successful report of microbial production of the artificial chemicals, acetins.
- Jeong, Seong-Hee,Joo, Seongjoon,Kim, Kyung-Jin,Kim, Seon-Won,Seo, Hogyun,Sohn, Jung-Hoon,Tseten, Tenzin,Wang, Chonglong,Zada, Bakht
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- Novel double-SO3h functionalized ionic liquid for acetylation
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Novel double-SO3H functionalized ionic liquid (DFIL) was synthesized and its catalytic activities for acetylation studied. The result showed that the DFIL possess high acidity and was very efficient for the acetylation of alcohols, amines and phenols with good to excellent yields in short reaction times. Operational simplicity, stability to water and air, small amounts needed, low cost, high yields, high acidity, applicability to large-scale reactions and reusability are the key features of the DFIL, which indicated promising applications of DFIL in green chemical processes. Pleiades Publishing, Ltd., 2012.
- Zhu, Lili,Liang, Xuezheng
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- Screening of different solid acid catalysts for glycerol acetylation
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Different solid acid catalysts, sulfonic acid functionalized amorphous and mesoporous silicas, titania doped silica HMS, sulfated zirconia and niobic acid, were synthesized, characterized and tested in the esterification reaction of glycerol. Their catalytic performance was compared with that of commercial Amberlyst-15. Fresh and spent materials were analyzed by means of X-ray photoelectron spectroscopy, N2 adsorption isotherms and acid capacity measurements. Among all the catalysts the mesoporous sulfonic silica presented the best performance in term of reactivity, with the total conversion of glycerol in 30 min of reaction, and in term of stability, with no leaching of sulfonic groups of catalyst. The catalytic activity of the materials was related to their acid capacities as well as to the strength and surface density of acidic sites.
- Testa, Maria Luisa,La Parola, Valeria,Liotta, Leonarda F.,Venezia, Anna Maria
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- Continuous synthesis of glycerol acetates in supercritical carbon dioxide using Amberlyst 15
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Continuous esterification of glycerol with acetic acid was investigated in supercritical carbon dioxide (scCO2) using Amberlyst 15 as a heterogeneous catalyst. The effect of pressure at (65-300) bar on the substrate conversion and the reaction yield and selectivity was studied. With increasing pressure, the percent of total yield and conversion remain almost unaffected and the selectivity of monoacetin synthesis increases while the selectivity for triacetin stays relatively unchanged. The effect of temperature on the yield, conversion, and the selectivity at (100-150) °C was also investigated. With increasing temperature from 100 to 140 °C, the selectivity for monoacetin decreases while for tri- and diacetin slightly increases. In contrast, with further increase in temperature, from 140 °C to 150 °C, the selectivity of monoacetin synthesis increases while that of diacetin decreases. By increasing the molar ratio of acetic acid to glycerol to 24, a selectivity of 100% was achieved for 2 h while the yield was 41% for the continuous triacetin synthesis in scCO2. When neat scCO2 as solvent with no catalyst was used, only monoacetin with 29% conversion was synthesized. The catalyst durability was also studied by monitoring the reaction for 25 h. The results show that the catalyst retains its activity even for 25 h but the selectivity for triacetin synthesis declines from 100% to about 60%.
- Rezayat, Marzieh,Ghaziaskar, Hassan S.
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- Investigation of Sn(IV) catalysts in glycerol acetylation
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The catalysts dibutyltin dichloride (Bu2SnCl2), dimethyltin dichloride (Me2SnCl2), butyltin trichloride (BuSnCl3), dibutyltin dilaurate (Bu2SnLau2), butyl stannoic acid [BuSnO(OH)], and di-n-butyl-oxo-stannane (Bu2SnO) were investigated in the acetylation of glycerol (GLY). To the best of our knowledge, this is the first time that this family of catalysts is employed for this reaction and the catalysts bearing chlorine substituents provided the best results. The most active system (BuSnCl3) leads to the total conversion of GLY and shows very good selectivity (25.7, 43.5 and 30.8 percent for MA, DA and TA, respectively) under mild reaction conditions (80 °C, AA:GLY molar ration of 4:1 with 3 h of reaction). The apparent rate constants (kap) for the GLY conversion confirm these results, since values of 29.1 × 10?3, 67.9 × 10?3 and 87.2 × 10?3 h?1 were obtained at 40, 80 and 120 °C, respectively. The activation energy for GLY conversion was determined and for the reaction performed without catalyst the estimated value was 23.9 kJ mol?1 while using BuSnCl3 it was 14.3 kJ mol?1, representing a decrease of around 50 percent.
- Altino, Felyppe M. R. S.,Bortoluzzi, Janaína H.,Meneghetti, Simoni M. P.,da Silva, Débora S.
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- Combining clays and ultrasound irradiation for an o-acetylation reaction of N-glucopyranosyl and other molecules
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A convenient, efficient and fast acetylation combining clays and ultrasound irradiation is described. Some molecules from nature or synthetic source, i.e., D-glucose, glycerol, D-mannitol and 1,2,3-triazolic derivatives such as N-glucosyl sugars and 2-substituted 1,4-naphthoquinone structures were acetylated. This kind of chemistry may be classified as eco-friendly because the reactions take a short time and the catalyst is reusable.
- De Oliveira, Ronaldo N.,De Xavier, Augusto L.,Guimaraes, Bruna M.,Melo, Valentina N. E.,Valena, Wagner O.,Nascimento Do, Wilson S.,Da Costa, Pollyanna L. F.,Camara, Celso A.
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- Co-production of butyrate methyl ester and triacetylglycerol from tributyrin and methyl acetate
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The simultaneous synthesis of butyric acid methyl ester, the shortest component of the FAME (fatty acid methyl esters) family, and glycerol triacetate (TAG) from glycerol tributyrate (tributyrin) and methyl acetate was studied as a function of several reaction parameters, such as type of catalyst, temperature and products distribution. The reaction is an interesterification, a multistep consecutive ester interchange catalyzed by either acid or base catalyst. Under optimized conditions, a complete tributyrin conversion and an almost quantitative butyric acid methyl ester accumulation were achieved. The other reaction product, TAG, formed by the complete acetylation of the glycerol moiety, reached almost 70% yield, whereas the mono- and di-acetylated intermediates accumulated in the order of 5-8% and 24-27%, respectively. Similar final conversions and products yields were obtained with either acid or base homogeneous catalysts, suggesting that the final products mixture did not depend on the type of catalysis but might be limited by equilibrium conditions. In spite of similar final yields, base catalysis needed shorter reaction times (minutes instead of hours) and lower temperature (60 °C instead of 130 °C) with respect to the best acid catalyst. On the other hand, unlike heterogeneous basic catalysts, which showed low activity, a heterogeneous acid catalyst almost as active as the homogenous counterpart was found.
- Battistel, Ezio,Calaprice, Chiara,Gualdi, Enrico,Rebesco, Elena,Usai, Elisabetta Maria
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- POSS-derived solid acid catalysts with excellent hydrophobicity for highly efficient transformations of glycerol
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Novel excellent hydrophobic POSS-derived solid acid catalysts were successfully synthesized through free radical copolymerization of polyhedral oligomeric vinylsilsesquioxanes (POSS) with sodium p-styrene sulfonate (POSS-x-SO3H), and characterized by several physicochemical methods. Green routes toward valorization of glycerol via acetalization with benzaldehyde and esterification of glycerol with acetic acid have been proposed. The as-prepared catalysts showed very high activities and selectivities toward glycerol derivatives within a short reaction time, which were even higher than that of homogeneous H2SO4. The POSS-2-SO3H catalyst was recycled up to five times without any significant loss of activity. The excellent performance of these solid acid catalysts is mostly attributed to the combination of superior hydrophobicity and large specific surface area.
- Leng, Yan,Zhao, Jiwei,Jiang, Pingping,Lu, Dan
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- Solventless acetylation of alcohols and phenols catalyzed by supported iron oxide nanoparticles
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Supported iron oxide nanoparticles on silicate catalysts were found to be efficient and easily recoverable materials in the acetylation of alcohols and phenols to their corresponding acetyl compounds using acetic anhydride under mild and solvent-less conditions. The supported iron oxide nanoparticles could be easily recovered from the reaction mixture and reused ten times without any loss in activity.
- Rajabi, Fatemeh,Luque, Rafael
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- Acetylation of alcohols and phenols with acetic anhydride under solvent-free conditions using an ionic liquid based on morpholine as a recoverable and reusable catalyst
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Rapid and efficient acetylation of alcohols and phenols with acetic anhydride is performed in the presence of economical Bronsted acidic ionic liquids that bear a propanesulfonic acid group on a morpholinium cation as catalysts under solvent-free conditions. [MMPPA][HSO4] (N-methylmorpholinium propanesulfonic acid ammonium hydrogensulfate) was proven to be the most active catalyst, and after removal of water, it could be recycled and reused for up to four times without a noticeable decrease in catalytic activity. Springer-Verlag 2010.
- Yue, Caibo,Liu, Qingqing,Yi, Tingfeng,Chen, Yun
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- A cheap, simple, and versatile method for acetylation of alcohols and phenols and selective deprotection of aromatic acetates under solvent-free condition
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Acyclic and cyclic acetates of various alcohols and phenols were obtained in excellent yields under mild reaction conditions in the presence of a catalytic amount of sodium hydroxide under solvent-free conditions and microwave irradiation. Selective deprotection of acetate group from the corresponding phenolic compounds was carried out in the presence of LiClO4· 2H2O. Copyright Taylor & Francis, Inc.
- Rajabi, Fatemeh,Saidi, Mohammad R.
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- A heterogeneous cobalt(II) Salen complex as an efficient and reusable catalyst for acetylation of alcohols and phenols
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Acetylation of various alcohols and phenols was performed successfully using an immobilized cobalt(II) catalyst in high yield. The catalyst shows high thermal stability and was also recovered and reused at least 10 times without any considerable loss of activity.
- Rajabi, Fatemeh
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- Selective Synthesis of Carbonates from Glycerol, CO 2, and Alkyl Halides Using tert -Butyltetramethylguanidine
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Herein, we describe the guanidine-promoted synthesis of carbonates from glycerol, CO 2, and alkyl halides. Specifically, a linear tricarbonate (1,2,3-tri- O -butoxycarbonylglycerol), a dicarbonate [butyl (2-oxo-1,3-dioxolan-4-yl)methyl carbonate] containing a linear and a cyclic moiety, and a cyclic monocarbonate (4-hydroxymethyl-2-oxo-1,3-dioxolan) were selectively obtained in good yields, which were strongly affected by the steric bulkiness of the guanidine group substituents. The developed method exhibits the advantages of high efficiency and mild conditions, thus being a powerful tool for the synthesis of value-added products from industrial by-products.
- Mihara, Masatoshi,Moroga, Kaname,Iwasawa, Tetsuo,Nakai, Takeo,Ito, Takatoshi,Ohno, Toshinobu,Mizuno, Takumi
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- Zr-modified hierarchical mordenite as heterogeneous catalyst for glycerol esterification
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Hierarchical mordenite catalysts were prepared by HF and NH4F etching. Materials' zirconia modification was performed by incipient wetness impregnation in order to vary surface acidity type and strength. XRD, N2 physisorption, solid-state NMR and UV–Vis spectroscopies were applied for characterization. Acidic properties of the obtained materials were investigated by TPD of adsorbed ammonia and FT-IR spectra of adsorbed pyridine. Catalytic performance was studied for the glycerol esterification with acetic acid. Zr increased reaction turnover activity compared to raw zeolite substrate due to abundant Br?nsted and Lewis moiety presence. The demonstrated biomass valorization processes to bio-based platform chemicals are of interest, as they employ biodiesel production waste.
- Popova, Margarita,Lazarova, Hristina,Kalvachev, Yuri,Todorova, Totka,Szegedi, ágnes,Shestakova, Pavletta,Mali, Gregor,Dasireddy, Venkata D.B.C.,Likozar, Bla?
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- Highly efficient and versatile acetylation of alcohols catalyzed by cerium(III) triflate
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Cerium(III) triflate is a powerful catalyst for the acetylation of alcohols. The reaction works well for a large variety of simple and functionalized alcohols, without isomerisation of chiral centres. Changes of hydroxyl protective groups are possible in a one-pot procedure. The catalyst can be easily recycled.
- Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Procopio, Antonio,Nardi, Monica,Bartoli, Giuseppe,Romeo, Roberto
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- Zeolite catalyzed ring opening of epoxides to acetylated diols with acetic anhydride
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HY Zeolite is found to be a versatile catalyst for opening of epoxides to the corresponding acetylated 1,2-Diols with acetic anhydride in good yields.
- Ramesh,Niranjan Reddy,Venugopal,Subrahmanyam,Venkateswarlu
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- Sulfamic acid catalysed acetylation of alcohols and phenols with acetic anhydride
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An easy acetylation of alcohols and phenols with acetic anhydride has been carried out in excellent yield under catalysis of sulfamic acid.
- Jin, Tong-Shou,Ma, Van-Ran,Zhang, Zhan-Hui,Li, Tong-Shuang
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- Acetylation of Glycerol over Highly Stable and Active Sulfated Alumina Catalyst: Reaction Mechanism, Kinetic Modeling and Estimation of Kinetic Parameters
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The Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic model was developed for acetylation of glycerol over highly stable and active 2 M SO4 2?/γ-Al2O3 catalyst. The apparent reaction rate constants were determin
- Pankajakshan, Arun,Pudi, Satyanarayana Murty,Biswas, Prakash
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- SbCl3 as a highly efficient catalyst for the acetylation of alcohols, phenols, and amines under solvent-free conditions
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Antimony trichloride has been found to be an efficient and expedient catalyst for the acylation of alcohols, phenols, amines, and sugars with acetic anhydride in high yields and in a short reaction time under solvent-free conditions at room temperature. Also, racemization of chiral alcohols and epimerization of sugars were not observed in any of the substrates. Copyright Taylor & Francis Group, LLC.
- Bhattacharya, Asish K.,Diallo, Mamadou A.,Ganesh, Krishna N.
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- The Esterification of Carboxylic Acid with Alcohol over Hydrous Zirconium Oxide
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The esterification of carboxylic acids with alcohols proceeded efficienly with hydrous zirconium oxide to give the corresponding esters in the vapor phase, in the liquid phase, and in an autoclave.The steric hindrance of carboxylic acids and alcohols affected the esterification by lowering the reactivity.With a rise in the reaction temperature, the conversion of the carboxylic acid increased.The dehydration of alcohols was prevented by using hydrous zirconium oxide in spite of the high reaction temperature.The reaction rate is first-order with respect to the concentration of the catalyst and an alcohol and is inversely proportional to thta of the carboxylic acid.Transesterification also proceeded efficiently.
- Takahashi, Kyoko,Shibagaki, Makoto,Matsushita, Hajime
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- Sulphuric acid-functionalized siliceous zirconia as an efficient and reusable catalyst for the synthesis of glycerol triacetate
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In the present study, a sulphated siliceous zirconia catalyst (SSZ-550) has been prepared and characterized by XRD and FTIR analysis to indicate the incorporation of sulphate group over the matrix. X-ray photoelectron spectroscopy also revealed that sulphur group was incorporated over the matrix to impart the Br?nsted acidity to the catalyst which is vital for the acetylation activity. To optimize the reaction parameters, viz. reagent molar ratios (3–12; glycerol/acetic acid), catalyst amount (1–5?wt%; catalyst/glycerol), reaction duration (20–50?min) and reaction temperature (30–100?°C) have been varied to obtain the optimum catalyst activity for the maximum glycerol triacetate yield. Finally, under the optimized reaction parameters of 9:1 glycerol/acetic acid molar ratio, 3?wt% catalyst, 80?°C reaction temperature and 40?min of reaction duration, a 93% glycerol triacetate yield was obtained. The catalyst was recovered from the reaction mixture and reused during six consecutive reaction runs while retaining 50% glycerol triacetate selectivity in the last cycle. A plausible mechanism suggests the heterogeneous catalyst-assisted protonation of carbonyl group of acetic acid to initiate the stepwise esterification of the hydroxyl groups of glycerol.
- Abida, Km,Ali, Amjad
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- Yttria-zirconia based Lewis acid: An efficient and chemoselective catalyst for acylation reactions
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Yttria-zirconia based strong Lewis acid efficiently catalyzes acylation of alcohols, amines and thiols under environmentally safe, heterogeneous reaction conditions with high selectivity and in excellent yields.
- Kumar,Pandey,Bodas,Dongare
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- Chemical transformation of embelin through dimerization during preparation of a decoction
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Embelin, a major constituent of Embelia ribes BURM. (Myrsinaceae) was transformed into different types of compounds through dimerization during preparation of a decoction. Two of the products are proposed to have furanylidene benzofuranone and 1,4-dibenzofurandione skeletons on the basis of spectroscopic means. The transformation of embelin in boiling water is markedly accelerated by the presence of fatty acids.
- Kiuchi, Fumiyuki,Suzuki, Noriko,Fukumoto, Yumiko,Goto, Yoshihisa,Mitsui, Mariko,Tsuda, Yoshisuke
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- Acylated oligosaccharides from Klebsiella K63 capsular polysaccharide: depolymerization by partial hydrolysis and by bacteriophage-borne enzymes.
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The extracellular polysaccharide from Klebsiella K63 is unique in having acetic and formic ester groups attached to the D-galactopyranosyluronic residues in the trisaccharide repeating-sequence. These O-acyl substituents are shown to be somewhat resistant to mild hydrolysis by both acid and alkali. Bacteriophage-induced depolymerization of the polysaccharide generated a series of acylated oligosaccharides comprising one, or more, repeating unit(s). By mild hydrolysis with acid, the same series of oligomers was released from the polysaccharide, together with the corresponding non-acylated compounds and the expected acylated and non-acylated aldobiouronic acids. A study of these oligosaccharides, as well as of a number of their related compounds, is described, with particular emphasis on the methods used to locate the formic and acetic ester groups. The location of the O-acyl substituents on the galactosyluronic residues was further supported by the results obtained from the high-resolution, 400-MHz, p.m.r. spectra and 13C-n.m.r. spectra of a number of the oligosaccharides.
- Dutton,Merrifield
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- Biodiesel Glycerin Valorization into Oxygenated Fuel Additives
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Current industrial methods of biodiesel production lead to an excess of crude glycerin which requires costly purification before commercialization. Production of oxygenated fuel additives is a potential route for glycerin valorization. Glycerin acetylation was carried out over heterogeneous acid catalysts (15%, glycerol weight basis) using glacial acetic acid (molar ratio = 9). The catalysts, containing different amounts of phosphate species (P/Si from 10 to 20 atomic ratio), were prepared by wet impregnation of commercial silica with aqueous solutions of diammonium phosphate and ortho-phosphoric acid. X-ray diffraction patterns of calcined solids presented amorphous patterns like raw silica. The prepared catalysts presented, at 120?°C, glycerol conversion higher than 89.5% after 1?h of reaction, been diacetin the major product, with triacetin selectivities lower than 26.1%. Diacetin selectivity was found to be almost invariant with catalyst acidity thus underlining the relevance of catalyst porosity due to the large acetins molecules sizes. The slow rate of triacetin diffusion in narrow pores of catalyst might be responsible for the relatively low yield obtained. Surface phosphate species showed a slow rate of leaching in the reaction medium showing high catalyst stability. Graphical Abstract: [Figure not available: see fulltext.]
- Catarino, Mónica,Gomes Fonseca, Frederico,Gomes, Jo?o,Soares Dias, Ana Paula
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- A highly active and stable organic-inorganic combined solid acid for the transesterification of glycerol under mild conditions
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Solid acid catalyst plays a crucial role in the petroleum refinery industry and bio-refinery technology. In this work, p-phenolsulfonic acid (PSA) was successfully grafted onto the surface of KH560-modified zirconium phosphate (K-ZrP) in a facile routine. The structure and property of this organic-inorganic combined solid acid PSA/K-ZrP-x were characterized via XRD, FTIR, 13C solid-state NMR, TG, N2 adsorption-desorption, SEM, pyridine-adsorption FTIR and XPS technologies. The characterization results showed that KH560 can bond with ZrP and promote the grafting of PSA on the surface of K-ZrP via the condensation reaction between its epoxy ring and the phenolic hydroxyl group in PSA. Consequently, PSA/K-ZrP-2 exhibited excellent performance and stability in the transesterification between glycerol and methyl acetate among the tested H3PW12O40, Amberlyst-45, HBEA, HZSM-5, ZrP, AlCl3 and FeCl3 catalysts. The calculated conversion of glycerol reached 81.3% with a 97.9% selectivity for monoacetin (MAG) and diacetin (DAG) with a 2.2% dosage of [H+] at 100 °C for 4 h. The highest specific activity of PSA/K-ZrP-2 reached 24028.2 mg-glycerol/g-cat/h in a short reaction time (at 0.17 h), and it could be recycled five times without obvious deactivation.
- Hou, Zhaoyin,Jiang, Yuanyuan,Long, Yihua,Wang, Zhengbao,Ye, Boyong,Zhao, Huaiyuan,Zhou, Ruru
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p. 1772 - 1781
(2021/06/28)
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- ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
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Paragraph 0011; 0027
(2021/01/29)
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- Ordered mesoporous zirconium silicates as a catalyst for biofuel precursors synthesis
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Zirconium incorporated three-dimensional ordered mesoporous silica (FDU-5) catalysts with different Si/Zr (100, 50 and 25) ratios were synthesized using an Evaporation Induced Self Assembly (EISA) method to maximize the incorporation of zirconium sites in the silica framework. The physicochemical properties of the synthesized materials were characterized by several techniques such as XRD, N2 sorption, diffuse reflectance UV–Vis, TEM, ammonia TPD, ICP-OES and pyridine adsorbed FT-IR. The catalytic activity was evaluated in acid-catalyzed esterification of glycerol with acetic acid. The effects of different reaction parameters were studied to optimize the maximum yields, such as reaction temperature, catalyst loading, acid/alcohol molar ratio, and reaction time. Esterification of glycerol with levulinic acid and levulinic acid with ethanol was also performed to synthesize fuel precursors. Reaction results showed that the prepared Zr-FDU-5(25) material was a very high catalytic activity, which depended mostly on the zirconium species' availability on the surfaces and framework. This zirconium containing FDU-5 material was very active in the esterification reaction and selective product formation at certain reaction conditions. The selected catalyst was recycled five times without significant loss in its activity.
- Bu, Quan,Cai, Jin,Mao, Hanping,Vasudevan, Srinivasan Vinju
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- A comparative study on porous solid acid oxides as catalysts in the esterification of glycerol with acetic acid
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Acid catalysts comprising of porous SiAl, as well as molybdophosphoric heteropolyacid, supported SiAl nanotubes were synthesized. The characterizations were through scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), termoprogrammed ammonia desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR). Esterification of glycerol into acetins reaction was evaluated over two series of SiAl-based solids. Both series displayed very good activity as well as selectivity towards the acetins within a short reaction time. However, porous SiAl deactivated due to acid sites leaching in long-term catalytic runs. The tuning of the loadings of the molybdophosphoric amount on SiAl halloysite nanotubes leads to an increase in the selectivity towards the mono, di, and triacetins. These catalysts were also recycled up to three times, and a 17 percent of conversion and 100 percent of selectivity for triacetin were obtained due to the combination of acidity, stable structure and porosity of the molybdophosphoric supported SiAl nanotubes.
- Araujo, Jesuina C. S.,Campos, Adriana F.,Filho, Josué M.,Freire, Paulo T. C.,Lang, Rossano,Neto, Antonio B. S.,Oliveira, Alcineia C.,Rodriguez-Castellón, Enrique,Sousa, Francisco F. F.
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- A transesterification-acetalization catalytic tandem process for the functionalization of glycerol: The pivotal role of isopropenyl acetate
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At 30 °C, in the presence of Amberlyst-15 as a catalyst, a tandem sequence was implemented by which a pool of innocuous reactants (isopropenyl acetate, acetic acid and acetone) allowed upgrading of glycerol through selective acetylation and acetalization processes. The study provided evidence for the occurrence of multiple concomitant reactions. Isopropenyl acetate acted as a transesterification agent to provide glyceryl esters, and it was concurrently subjected to an acidolysis reaction promoted by AcOH. Both these transformations co-generated acetone which converted glycerol into the corresponding acetals, while acidolysis sourced also acetic anhydride that acted as an acetylation reactant. However, tuning of conditions, mostly by changing the reactant molar ratio and optimizing the reaction time, was successful to steer the set of all reactions towards the synthesis of either a 1?:?1 mixture of acetal acetates (97% of which was solketal acetate) and triacetin, or acetal acetates in up to 91% yield, at complete conversion of glycerol. To the best of our knowledge, a one-pot protocol with such a degree of control on the functionalization of glycerol via transesterification and acetalization reactions has not been previously reported. The procedure was also easily reproduced on a gram scale, thereby proving its efficiency for preparative purposes. Finally, the design of experiments with isotopically labelled reagents, particularly d4-acetic acid and d6-acetone, helped to estimate the contribution of different reaction partners (iPAc/AcOH/acetone) to the formation of final products. This journal is
- Calmanti, Roberto,Perosa, Alvise,Rigo, Davide,Selva, Maurizio
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supporting information
p. 5487 - 5496
(2020/09/23)
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- Single-pot template-free synthesis of a glycerol-derived C-Si-Zr mesoporous composite catalyst for fuel additive production
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Synthesis of a highly ordered mesoporous acid- as well as metal-functionalized carbon (-SO3H/C-Si-Zr) material is achieved for the first time from a simple single-pot template-free carbonization of low-value bio-derived glycerol. Addition of TEOS to glycerol right before the carbonization was observed to facilitate molecular-level interactions between them to establish C-Si bonding, which eventually leads to the formation of a high surface area mesoporous -SO3H/C-Si composite material. Unlike this, the addition of ZrO(NO3)2·xH2O to glycerol could not have such an effect, but when Zr is used in the presence of TEOS the mixture could successfully produce the -SO3H/C-Si-Zr composite possessing mesoporosity and uniform acidity suitable for bulky tri-acetin production useful for fuel applications. Here TEOS is observed to play two roles, (1) as a surface area and porosity improver of graphitic carbon by its C-Si interaction and (2) as a mediator to involve Zr in the carbon composite structure through its Si-OH group. Thus, the combined inclusion of Zr and Si sources in the glycerol-derived carbon structure could successfully introduce the positive aspects of porosity improvement (by Si) and acidity improvement (by zirconia) in the mixed composite -SO3H/C-Si-Zr to produce the highest ever selectivity of tri-acetin (～94 wt%) from the same low-value bio-derived glycerol by an acetylation reaction. The sustainability of the process lies in the utilization of waste glycerol as a source of the carbon composite, which in turn catalyzes selective low-value glycerol conversion to industrially important fuel additives.
- Al-Muhtaseb, Ala'A H.,Diwakar, Jitendra,Kumar, Saurabh,Saxena, Sandeep K.,Selvamani, Arumugam,Viswanadham, Nagabhatla
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supporting information
p. 8254 - 8263
(2020/06/10)
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- Glycerol acetylation considering competing dimerization
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Glycerol acetylation is a very interesting reaction for studies of consecutive kinetics. In this short communication, we present a pseudo-homogeneous model for the synthesis of triacetyl glycerol from the reaction of glycerol and acetic acid over strongly acidic Amberlyst-15 and Amberlyst-70 catalysts, considering a dimerization of diacetyl glycerol (DAG) into diglycerol tetraacetate as a parallel reaction and compare the results with a model without side reactions. The best fits were obtained for apparent zeroth-order dimerization and first-order consecutive reactions in the presence of acetic acid in excess and with removal of water. An adaptation was made for DAG. The proposed model shows that the formation of DAG is faster than the consumption of glycerol, which could be an explanation for the occurrence of DAG dimerization instead of other parallel reactions in acetylation.
- Soares, André V.-H.,Kale, Sumeet S.,Armbruster, Udo,Passos, Fabio B.,Umbarkar, Shubhangi B.,Dongare, Mohan K.,Martin, Andreas
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p. 634 - 640
(2019/05/10)
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- Method for preparing glycerol triacetate under organic catalysis
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The invention discloses a method for preparing glycerol triacetate under organic catalysis. The method comprises the following step: allowing glycerol and acetic acid to generate an esterification reaction in the presence of an aminothiazole catalyst and a water-carrying agent so as to obtain the glycerol triacetate. According to the invention, the aminothiazole catalyst adopted in the method provided by the invention is a bifunctional hydrogen bond catalyst, has low toxicity and high efficiency, and improves the disadvantages of strong corrosivity and easy generation of side reactions for traditional liquid acid catalysts like concentrated sulfuric acid. Meanwhile, the glycerol triacetate provided by the invention has the following advantages: the synthetic method has simple process; advantages of high conversion rate and high selectivity are achieved; and the catalyst has less usage amount and can be separated and reutilized.
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Paragraph 0024; 0026; 0028; 0030; 0032; 0034; 0035; 0036
(2018/11/03)
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- The effect of an electron-withdrawing group in the imidazolium cation: The case of nitro-functionalized imidazolium salts as acidic catalysts for the acetylation of glycerol
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The acetylation of glycerol was achieved with high conversion and selectivity towards triacetin at low temperatures and short reaction times by using acidic imidazolium salts as catalysts. Moreover, the addition of a nitro group to the imidazolium cation affords a much more competent catalyst, indicating a significant effect provided by the simple electronic change in the imidazolium cation. Theoretical calculations revealed increased polarization of the acidic hydrogen bond on the nitrated salts, which may be related to their superior catalytic behavior when compared to the non-functionalized salts. Combining the preliminary experimental and theoretical results, it is possible to suppose that the catalytic activity of acidic imidazolium salts may be better comprehended by its Br?nsted acidities, but other parameters such as hardness, electronegativity, electrophilicity and ion-pair binding energy were also evaluated in order to investigate their effects in the acetylation of glycerol promoted by these acidic imidazolium salts.
- Morais, Eduardo M.,Grillo, Igor B.,Stassen, Hubert K.,Seferin, Marcus,Scholten, Jackson D.
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p. 10774 - 10783
(2018/07/05)
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- Metal-free transesterification catalyzed by tetramethylammonium methyl carbonate
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Environmentally benign metal-free tetramethylammonium methyl carbonate is effective as a catalyst for the chemoselective, scalable, and reusable transesterification of various esters and alcohols in common organic solvents. In situ-generated highly active species, tetramethylammonium alkoxides, can greatly avoid self-decomposition at ≤110 °C, and are reusable. In particular, chelating substrates, such as amino alcohols, diols, triols, sugar derivatives, alkaloids, α-amino acid esters, etc., which deactivate conventional metal salt catalysts, can be used. A 100 gram scale biodiesel production was also demonstrated.
- Hatano, Manabu,Tabata, Yuji,Yoshida, Yurika,Toh, Kohei,Yamashita, Kenji,Ogura, Yoshihiro,Ishihara, Kazuaki
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supporting information
p. 1193 - 1198
(2018/03/27)
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- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
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Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
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p. 13653 - 13667
(2017/03/11)
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- For producing fatty acid triglyceride method and of esterification reaction of esterification reaction device
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The invention relates to an esterification reaction method and device for production of fatty acid triglyceride. The esterification reaction method and device for production of fatty acid triglyceride have the characteristics of high reaction efficiency and short reaction time and can be used for producing high-content fatty acid triglyceride. The esterification reaction method comprises the following steps: (1) carrying out esterification reaction on a catalyst and glycerin; (2) controlling the reaction pressure and the reaction temperature in an esterification reactor; and (3) discharging the product of reaction through a discharge port. The esterification reaction device for production of fatty acid triglyceride comprises an esterification reactor and further comprises a pre-mixing tank and a fatty acid pre-heater, wherein the pre-mixing tank is communicated with a catalyst feed port and a glycerin feed port, the outlet of the pre-mixing tank is communicated with an atomizer, the bottom of the inner cavity of the esterification reactor is provided with a bubbling air sifter, the fatty acid pre-heater is communicated with a fatty acid feed port, the top of the esterification reactor is communicated with a fatty acid cooler and a vacuum device interface, and the bottom of the esterification reactor is provided with a discharge port.
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-
Paragraph 0030-0031
(2017/03/21)
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- Preparation method of glyceryl triacetate
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The invention discloses a preparation method of glyceryl triacetate. The preparation method comprises the following steps: 1, mixing and stirring concentrated sulfuric acid and activated carbon, wherein the pH value of the activated carbon is 1, the mass ratio of the sulfuric acid to the activated carbon is 1: 0.5-2, raising the temperature to 150-190 DEG C, preserving the temperature for 10-30 minutes, conducting natural cooling, then placing the mixture at the normal temperature, and obtaining a catalyst; 2, mixing the catalyst obtained in step 1 with glycerin, acetic acid and dehydrating agents, raising the temperature to 100-150 DEG C, getting the mixture to react, and obtaining glyceryl triacetate through post-treatment, wherein the volume mass ratio of glycerin to the catalyst is 1: 0.004-0.10. According to the preparation method, a novel catalytic reaction is adopted, esterification time is shortened by about 10 hours, energy is saved, and the cost is lowered; compared with a method in which concentrated sulfuric acid serves as a catalyst, the novel catalyst is used for preparing glyceryl triacetate, side reaction polymerization products are reduced, and product purity is raised to above 99.7% from 98.0-99.0%.
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Paragraph 0027; 0028
(2017/01/19)
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- Understanding the role of Keggin type heteropolyacid catalysts for glycerol acetylation using toluene as an entrainer
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The heterogeneously catalyzed esterification (acetylation) of glycerol toward triacetin in batch mode in presence of toluene as entrainer was studied. Silicotungstic acid, tungstophosphoric acid and phosphomolybdic acid as heteropolyacids (HPAs) supported on silica, alumina or silica-alumina were used as catalysts. The course of the reaction was found to be very sensitive to the nature of the HPA as well as the support. Solid characterization by Raman spectroscopy, XRD, and pyridine-FTIR revealed that only combinations of tungsten-based HPAs and silica support were able to preserve the structure of active component throughout the preparation process, which was essential to obtain active and selective catalysts. The interaction between HPA and support was decisive for stability and dispersion of the catalytically active species. With the best performing catalyst H4SiW12O40/SiO2, selectivity to triacetin reached 71% at complete conversion within 24?h. The high selectivity to triacetin is attributed the Br?nsted acidic sites originated from stabilized Keggin structure and continuous removal of water during course of reaction. Toluene is able to form azeotropic mixtures with water and acetic acid and keeps the reaction temperature below the boiling point of acetic acid. Thus, water-free reaction conditions can be established. The catalyst was reusable; however, the activity and selectivity towards triacetin slightly decreased in a repetition run due to loss of active sites.
- Kale,Armbruster,Eckelt,Bentrup,Umbarkar,Dongare,Martin
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- Volume accessibility of acid sites in modified montmorillonite and triacetin selectivity in acetylation of glycerol
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Organic acid treatment enhances the acidity and surface characteristics of montmorillonite clay by dealumination. Dealuminated and Al-clays were used for acetylation of glycerol with acetic acid. All clays used had comparable acidity but pore characteristics were different. Though glycerol conversions were similar but triacetin selectivity was different. Al-clay and acid treated clays showed poor and improved selectivity, respectively. This was attributed to increased pore volume around the acid sites, which facilitates the multiple acetylation of glycerol. The generated space around acid centers, termed as 'volume accessibility', helps glycerol to interact with acylium ions formed on the acid sites more effectively leading to formation of triacetin. Correlations were made between the changed characteristics of clays and triacetin yield. Among the different correlations, triacetin selectivity correlates well with the volume accessibility. The latter is quite useful in predicting the catalytic performance.
- Venkatesha,Bhat,Prakash, B. S. Jai
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p. 45819 - 45828
(2016/06/06)
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- Fe4(SiW12O40)3-catalyzed glycerol acetylation: Synthesis of bioadditives by using highly active Lewis acid catalyst
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In order to investigate the effect of Lewis acidic metals on the acid properties of Keggin heteropolyacids catalysts, a set of metal-exchanged HPAs (i.e. M3/nPW12O40, M3/nPMo12O40 and M4/nSiW12O40 (M?=?Cu, Co and Mn, n?=?2; M?=?Fe, n?=?3) were synthesized and their activity on glycerol esterification with acetic acid was evaluated. This procedure avoids the use of corrosive Br?nsted acid catalysts. Regardless of the heteropoly anion, the activity of catalysts in terms of metal cations followed the sequence: Fe3+>?Cu2+>?Mn2+>?Co2+. It has been found that among the HPAs, only H4SiW12O40 has the acidic protons that can be successfully exchanged with Fe3+ cations, resulting in Fe4(SiW12O40)3 salt, the most active and selective catalyst. The highest conversion (ca.99.9%) was achieved in Fe4(SiW12O40)3-catalyzed esterification reactions, along with the highest selectivity for di and triacetyl glycerol (ca.55 and 42%, respectively). Effects of temperature, stoichiometry of reactants, concentration and nature of catalysts were assessed. A kinetic study of Fe4(SiW12O40)3 or H4SiW12O40-catalyzed reactions was conducted and the activation energy determined.
- Da Silva, Márcio José,Liberto, Natalia Aparecida,De Andrade Leles, Lorena Cristina,Pereira, Ulisses Alves
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- Selective formation of triacetin by glycerol acetylation using acidic ion-exchange resins as catalyst and toluene as an entrainer
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Esterification of glycerol with acetic acid in the presence of toluene as an entrainer was performed over acidic Amberlyst ion-exchange resins in a batch reactor. Toluene continuously removed the reaction water, thus the chemical equilibrium was effectively shifted; the selectivity for the most desired product triacetin was dramatically increased. The influence of reaction conditions such as reaction time, acetic acid: glycerol molar ratio and catalyst amount were investigated. More than 95% selectivity to triacetin at complete glycerol conversion was obtained. The ion-exchange resin catalysts were reusable in subsequent runs, but due to some deactivation the triacetin yields deteriorated.
- Kale,Umbarkar,Dongare,Eckelt,Armbruster,Martin
-
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- METHOD FOR PRODUCING ESTER BY USING 4-METHYLTETRAHYDROFURAN AS SOLVENT
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PROBLEM TO BE SOLVED: To provide a method for producing an ester which is higher in safety and can be applied to a highly polar reaction raw material or the like. SOLUTION: There is provided a method for producing an ester by reacting an alcohol and a carboxylic acid in 4-methyltetrahydropyran. By using 4-methyltetrahydropyran as a reaction solvent, an ester can be produced more safely and the method is applicable to a highly polar reaction raw material. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0028; 0029; 0030; 0031
(2016/10/08)
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- Graphene oxide as a facile solid acid catalyst for the production of bioadditives from glycerol esterification
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Graphene oxide (GO) has proved to be a highly active and reusable solid acid catalyst for glycerol esterification with acetic acid in the synthesis of bioadditives diacylglycerol (DAG) and triacylglycerol (TAG). The effects of reaction temperature, molar ratio of acetic acid to glycerol, catalyst amount and reaction time were investigated. A 90.2% combined selectivity of DAG and TAG with complete glycerol conversion was achieved at 120 °C for 6 h over GO. Final characterization shows that the active site of GO is the remaining SO3H group.
- Gao, Xiaoqing,Zhu, Shanhui,Li, Yongwang
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- Biobased catalyst in biorefinery processes: Sulphonated hydrothermal carbon for glycerol esterification
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Sulphonated hydrothermal carbon (SHTC), obtained from d-glucose by mild hydrothermal carbonisation and subsequent sulphonation with sulphuric acid, is able to catalyse the esterification of glycerol with different carboxylic acids, namely, acetic, butyric and caprylic acids. Product selectivity can be tuned by simply controlling the reaction conditions. On the one hand, SHTC provides one of the best selectivity towards monoacetins described up to now without the need for an excess of glycerol. On the other hand, excellent selectivity towards triacylglycerides (TAG) can be obtained, beyond those described with other solid catalysts, including well-known sulphonic resins. Recovery of the catalyst showed partial deactivation of the solid. The formation of sulphonate esters on the surface, confirmed by solid state NMR, was the cause of this behaviour. Acid treatment of the used catalyst, with subsequent hydrolysis of the surface sulphonate esters, allows SHTC to recover its activity. The higher selectivity towards mono- and triesters and its renewable origin makes SHTC an attractive catalyst in biorefinery processes.
- De La Calle, Carlos,Fraile, José M.,García-Bordejé, Enrique,Pires, Elísabet,Roldán, Laura
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p. 2897 - 2903
(2015/05/13)
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- Glycerol acetins: Fuel additive synthesis by acetylation and esterification of glycerol using cesium phosphotungstate catalyst
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Glycerol acetylation and esterification reactions with acetic anhydride and acetic acid respectively give acetins, in which di and tri acetins are commercially important products used as fuel additives. Acetylation and esterification of glycerol were studied over various solid acid catalysts namely, cesium phosphotungstate, amberlyst-15, H-beta, sulfated zirconia and montmorillonite K-10 under mild reaction conditions. The catalysts were characterized by XRD, FTIR, SEM and acidity measurements. Among all the catalysts evaluated in this study, cesium phosphotungstate showed highest activity with >98% conversion for both the reactions, whereas di and triacetins selectivity was 99.1% for acetylation and 75% for esterification reaction. The catalyst with high Br?nsted acidity gave high activity for both the reactions, whereas selectivity for di and tri acetins depends on nature of active sites.
- Sandesh, Swetha,Manjunathan, Pandian,Halgeri, Anand B.,Shanbhag, Ganapati V.
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p. 104354 - 104362
(2015/12/26)
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- A comparative study of the neutral and acidic polysaccharides from Allium macrostemon Bunge
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Neutral and acidic polysaccharides, named AMP40N and AMP40S respectively, were isolated and purified from the dried bulbs of Allium macrostemon Bunge. Both of them showed a single and symmetrically sharp peak, indicating they were homogeneous polysaccharides. Molecular weights of AMP40N and AMP40S were determined to be 18.2 and 105.1 kDa, respectively. AMP40N was composed of arabinose and glucose, while AMP40S was composed of rhamnose, arabinose, glucose and galactose and a certain amount of uronic acid. FT-IR, periodic acid oxidation, Smith degradation, methylation and GC-MS analysis revealed that non-reducing terminal and →2,6)-Glc-(1→ existed in AMP40N and AMP40S. The glycosidic linkage of arabinose in AMP40N was →2)-Ara-(1→, whereas it was Ara-(1→ in AMP40S. AMP40S had (1→2)-linked l-rhamnose residue. Both AMP40N and AMP40S exhibited strong anti-tumor potential against human gastric carcinoma cells BGC-823, in particular, AMP40S presented significantly higher inhibitory rate of 85.94% than AMP40N of 52.63%.
- Zhang, Zhanjun,Wang, Fuhua,Wang, Mingchun,Ma, Liping,Ye, Hong,Zeng, Xiaoxiong
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p. 980 - 987
(2015/01/09)
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- A simple acetylation of alcohols using ZnO nanopowder synthesized by microwave irradiation
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An efficient and selective method for acetylation of alcohols using ZnO nanopowder is described. In this method, alcohols are refluxed with a mixture of CH3COOH in the presence of catalytic amounts of ZnO nanopowder to afford their corresponding esters in good yields. This methodology is highly efficient for various structurally different alcohols: 1°, 2°, 3°. The prepared nano zinc oxide used in acetylation of alcohols which in comparison to ordinary ZnO has apparent advantages in promoting the yields of product formation.
- Javaherian, Mohammad,Sabzi, Hashem Eskandari
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p. 631 - 634
(2014/06/23)
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- Heteropolyacid-based ionic liquids as efficient homogeneous catalysts for acetylation of glycerol
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A series of homogeneous catalysts consisting of pyridinium propyl sulfobetaine (PPS), tungstophosphoric acid (TPA), and acetic acid (HOAc) have been synthesized and exploited for catalytic acetylation of glycerol (GL). Their acid properties were characterized by 31P NMR of trimethylphosphine oxide (TMPO) as the probe molecule, and the effects of acidic strength, PPS/TPA, TPA/GL, and HOAc/GL ratios as well as reaction temperature on catalytic performances during acetylation reaction were investigated. These water-tolerable PPS-TPA-HOAc catalysts, which tend to segregate from glycerol acetate products to form distinct biphasic liquid layers spontaneously after the reaction, were found to be highly efficient and durable for acetylation reaction under continuous operation conditions. Typically, a complete GL conversion may be achieved with a superior glycerol triacetate (GTA) selectivity of 86-99%. Moreover, the unique self-separation biphasic characteristics of the catalyst system facilitate facile separation of products and recycling of catalyst, rendering practical industrial applications in acetylation of alcohol.
- Huang, Ming-Yu,Han, Xiao-Xiang,Hung, Chin-Te,Lin, Jann-Chen,Wu, Pei-Hao,Wu, Jung-Chung,Liu, Shang-Bin
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- Heteropolyacid-based ionic liquids as efficient homogeneous catalysts for acetylation of glycerol
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A series of homogeneous catalysts consisting of pyridinium propyl sulfobetaine (PPS), tungstophosphoric acid (TPA), and acetic acid (HOAc) have been synthesized and exploited for catalytic acetylation of glycerol (GL). Their acid properties were characterized by 31P NMR of trimethylphosphine oxide (TMPO) as the probe molecule, and the effects of acidic strength, PPS/TPA, TPA/GL, and HOAc/GL ratios as well as reaction temperature on catalytic performances during acetylation reaction were investigated. These water-tolerable PPS-TPA-HOAc catalysts, which tend to segregate from glycerol acetate products to form distinct biphasic liquid layers spontaneously after the reaction, were found to be highly efficient and durable for acetylation reaction under continuous operation conditions. Typically, a complete GL conversion may be achieved with a superior glycerol triacetate (GTA) selectivity of 86-99%. Moreover, the unique self-separation biphasic characteristics of the catalyst system facilitate facile separation of products and recycling of catalyst, rendering practical industrial applications in acetylation of alcohol.
- Huang, Ming-Yu,Han, Xiao-Xiang,Hung, Chin-Te,Lin, Jann-Chen,Wu, Pei-Hao,Wu, Jung-Chung,Liu, Shang-Bin
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- Green Acetylation of Solketal and Glycerol Formal by Heterogeneous Acid Catalysts to Form a Biodiesel Fuel Additive
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A glut of glycerol has formed from the increased production of biodiesel, with the potential to integrate the supply chain by using glycerol additives to improve biodiesel properties. Acetylated acetals show interesting cold flow and viscosity effects. Herein, a solventless heterogeneously catalyzed process for the acetylation of both solketal and glycerol formal to new products is demonstrated. The process is optimized by studying the effect of acetylating reagent (acetic acid and acetic anhydride), reagent molar ratios, and a variety of commercial solid acid catalysts (Amberlyst-15, zeolite Beta, K-10 Montmorillonite, and niobium phosphate) on the conversion and selectivities. High conversions (72–95 %) and selectivities (86–99 %) to the desired products results from using acetic anhydride as the acetylation reagent and a 1:1 molar ratio with all catalysts. Overall, there is a complex interplay between the solid catalyst, reagent ratio, and acetylating agent on the conversion, selectivities, and byproducts formed. The variations are discussed and explained in terms of reactivity, thermodynamics, and reaction mechanisms. An alternative and efficient approach to the formation of 100 % triacetin involves the ring-opening, acid-catalyzed acetylation from solketal or glycerol formal with excesses of acetic anhydride.
- Dodson, Jennifer R.,Leite, Thays d C. M.,S. Pontes, Nathália,Peres Pinto, Bianca,Mota, Claudio J. A.
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p. 2728 - 2734
(2016/12/23)
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- Sulfonic acid functionalized deoxycellulose catalysts for glycerol acetylation to fuel additives
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Various forms of sulfonic acid (SO3H) functionalized cellulose-based heterogeneous catalysts were prepared, and their properties on glycerol acetylation reactions to mono-, di-, and triacetin products were investigated. Superior catalytic activity and stability for the reactions was observed on SO3H-NDOC catalyst that is obtained by (i) crosslinking of the cellulose units with epichlorohydrin into a three-dimensionally-networked deoxycellulose-matrix and (ii) sulfonic acid functionalization on the crosslinked deoxycellulose support via CS atomic linkages (CSO3H). It was found that sulfonic acid functionalization via an ether type OS atomic linkage (COSO3H) or the direct utilization of the pristine cellulose support without a fortification by crosslinking led to significant deactivation of the catalysts by substantial acidity loss. The intrinsic glycerol conversion turnover rate on SO3H-NDOC was comparable to that of commercial Amberlyst-15 solid resin, demonstrating the effectiveness of this renewable cellulose-derived heterogeneous catalyst for glycerol acetylation to fuel additives.
- Kim, Inbae,Kim, Jaesung,Lee, Doohwan
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- Method of Synthesizing Polyol Acetate by Using Catalyst of Ionic Liquid Heteropoly Acid
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The present invention uses a nitrogen-containing organic compound to be reacted with an alkyl sultone to obtain a zwitterion compound. The zwitterion compound is reacted with a heteropoly acid (HPA) to obtain an ionic liquid HPA (IL-HPA). The IL-HPA is used for acetylation of polyol and HOAc for obtaining polyol acetate. The IL used in the reaction can be recycled. Thus, problems of product separation, waste acid handling, and corrosion of facilities are solved and production through esterification is improved with a green catalysis.
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Paragraph [0032]
(2013/05/09)
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- Lewis basic ionic liquid as an efficient and facile catalyst for acetylation of alcohols, phenols, and amines under solvent-free conditions
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The Lewis basic ionic liquid 1,8-diazabicyclo[5.4.0]undec-7-en-8-ium acetate was employed for the acetylation of various phenols, alcohols, and amines in good-to-excellent yields at 50 C under solvent-free conditions in a short time. Compared with existing methods based on conventional catalysts and toxic solvents, the reported method is simple, mild and environmentally viable. Furthermore, the ionic liquid was conveniently separated from the products and easily recycled to catalyze other acetylation reactions with excellent yields. .
- Ji, Li,Qian, Chao,Chen, Xin-Zhi
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p. 369 - 374
(2013/05/21)
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- Catalytic activation of carbohydrates as formaldehyde equivalents for stetter reaction with enones
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We disclose the first catalytic activation of carbohydrates as formaldehyde equivalents to generate acyl anions as one-carbon nucleophilic units for a Stetter reaction. The activation involves N-heterocyclic carbene (NHC)-catalyzed C-C bond cleavage of carbohydrates via a retro-benzoin-type process to generate the acyl anion intermediates. This Stetter reaction constitutes the first success in generating formal formaldehyde-derived acyl anions as one-carbon nucleophiles for non-self-benzoin processes. The renewable nature of carbohydrates, accessible from biomass, further highlights the practical potential of this fundamentally interesting catalytic activation.
- Zhang, Junmin,Xing, Chong,Tiwari, Bhoopendra,Chi, Yonggui Robin
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supporting information
p. 8113 - 8116
(2013/07/19)
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- Yttrium-grafted mesostructured SBA-3 catalyst for the transesterification of glycerol with methyl acetate to synthesize fuel oxygenates
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The synthesis of di- and triacetyl glycerol (DAG and TAG) via the transesterification of glycerol with methyl acetate was investigated over series of solid acid catalysts prepared by grafting yttrium, 1-3.5 wt.%, into the framework of SBA-3 support. The p
- Khayoon,Hameed
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- Synthesis of bio-additives: Transesterification of ethyl acetate with glycerol using homogeneous or heterogeneous acid catalysts
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A new catalytic route with potential practical interest to sustainable production of bioadditives from glycerol is described. Ethyl acetate was transesterified with glycerol, in the ratio glycerol:EtOAc 1:10, at 25 or 90 °C using 0.1 equiv. of H2SO4 or TsOH, as homogeneous catalysts. H2SO4 led to the total glycerol consumption in 2 h. In the equilibrium, attained in 9 h, 100percent yield of a diacetin:triacetin (55:45) mixture was formed. Using Amberlyst? 15 dry and Amberlyst? 16 wet in 1:30 glycerol:EtOAc ratio and reflux at 90 °C the total glycerol consumption was achieved in 2 and 10h, respectively. The lower reactivity of Amberlyst-16 wet was explained in terms of deactivation of acid sites and decrease in glycerol diffusion to the inner resin pores, both factors caused by adsorbed water. The kinetics of glycerol transformation and product distribution in the equilibrium in relation to the H2SO 4, Amberlyst-15 (dry) and Amberlyst-16 (wet) catalyzed reactions were measured.
- Meireles, Bruno A.,Pereira, Vera Lu?cia P.
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- Development of niobium containing acidic catalysts for glycerol esterification
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Mesoporous silicate and niobiosilicate materials of SBA-15 type were prepared and post-synthesis modified with MPTMS, i.e. (3-mercaptopropyl) trimethoxysilane, followed by oxidation of thiol species. The samples obtained were characterised by different techniques (N2 adsorption/desorption, XRD, elemental and thermal analyses) and applied as catalysts in glycerol esterification with acetic acid. The focus was on the comparison of the role of niobium in the formation of sulphonic species and its stability in the post-synthesis modified materials (prepared within this work) with those, already published, prepared by one-pot synthesis method. The most important finding is that the presence of niobium in the SBA-15 structure improves the efficiency of -SH oxidation by hydrogen peroxide towards sulphonic species like in case of one-pot synthesised samples. However, contrary to the latter samples the presence of niobium does not increase the stability of the modifier (oxidized MPTMS). This has an impact on faster deactivation of samples prepared. Samples prepared with post-synthesis modification exhibit much higher activity in glycerol esterification.
- Trejda, MacIej,Stawicka, Katarzyna,Dubinska, Anna,Ziolek, Maria
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experimental part
p. 129 - 134
(2012/08/13)
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- The role of Nb in the formation of sulphonic species in SBA-15 and MCF functionalised with MPTMS
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Mesoporous silica and niobiosilicate materials of SBA-15 and MCF types were prepared in the presence of MPTMS, i.e. (3-mercaptopropyl)trimethoxysilane and hydrogen peroxide. The samples obtained were characterised by different techniques (N2 adsorption/desorption, XRD, elemental and thermal analyses) and applied as catalysts in glycerol esterification with acetic acid. The role of niobium species on the formation of sulphonic species and stability of organosilane modifier was explored. The most important finding is that the addition of niobium to the synthesis gel improves the efficiency of -SH oxidation by hydrogen peroxide towards sulphonic species. This behaviour is not dependent on the type of structure of mesoporous materials (SBA-15 or MCF). However, the kind of mesoporous solid influences the efficiency of Nb incorporation and on the esterification process. MCF matrix improves the catalytic performance of the MPTMS modified catalyst.
- Trejda, Maciej,Stawicka, Katarzyna,Ziolek, Maria
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p. 130 - 135
(2013/01/13)
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