- Dehydrative Esterification of Carboxylic Acids with Alcohols Catalyzed by Polymer-Supported Sulfonic Acids in Water
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Dehydrative esterification of carboxylic acids with alcohols in water was efficiently catalyzed by hydrophobic polystyrene-supported sulfonic acids as recoverable and reusable catalysts. In these reactions, esters were obtained in high yields without using any dehydrating agents or apparatus. The sulfonic acid contents of the catalysts and the presence of long alkyl chains on the benzene rings of polystyrene significantly affected the catalytic activity.
- Manabe, Kei,Kobayashi, Shu
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- Effect of ionic liquids, organic solvents and supercritical CO2 pretreatment on the conformation and catalytic properties of Candida rugosa lipase
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The objective of this work is to assess the structure and activity of Candida rugosa lipase (CRL) pretreated with seventeen ionic liquids (ILs), five organic solvents and super-critical carbon dioxide (SC-CO2). The results revealed that anion selection of ILs showed generally much greater effects on CRL esterification activity than cation choice, and CRL pretreated by ILs with strong water miscible properties showed very low esterification activity. The highest CRL activity treated with ILs [Hmim][PF6] was obtained with the value of 45078.0 U/g-protein. Furthermore, the CRL activities pretreated with five conventional organic solvents were also examined and the values increased with the log P decrease of organic solvents when log P was lower than 2.0. Finally, the CRL activities were respectively 1.2- and 1.3-fold higher over the untreated ones after pretreatment with sub- and super-critical CO2 under the pressures of 6 MPa and 15 MPa at 40 °C for 20 min. Further analyses via FT-IR demonstrated that the high activity of CRL pretreated with ILs, organic solvents and SC-CO2 was probably caused by the changes of CRL secondary structure. In conclusion, the results in this work will be helpful for us to choose the suitable reaction medium in CRL biocatalysis and biotransformation reactions.
- Liu, Yun,Chen, Dawei,Yan, Yunjun
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- Sugar ester-modified lipase for the esterification of fatty acids and long-chain alcohols
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The esterification reaction of a long-chain fatty acid and a fatty alcohol with a surfactant-modified lipase in a microaqueous n-hexane system was studied. Various lipases from different sources were first modified with a surfactant of the sugar ester type to improve their dispersibility in apolar organic solvents. This enzyme modification technique converted inactive crude lipases to highly active biocatalysts for the esterification of long-chain fatty acids and fatty alcohols in a microaqueous n-hexane system. The hydrophilic-lipophilic balance value and chainlength of the fatty acid residue of the fatty acid sugar ester, used for modifying the lipases, significantly influenced the amount of precipitated lipase that was dissolved in the aqueous solution, the protein content of the lipase-surfactant complex and its esterification activity.
- Basheer, Sobhi,Nakajima, Mitsutoshi,Cogan, Uri
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- Facile aerobic photooxidation of alcohols in the presence of catalytic lithium bromide
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Alcohols were found to be oxidized to the corresponding carboxylic acids in the presence of catalytic lithium bromide under photoirradiation. Georg Thieme Verlag Stuttgart.
- Itoh, Akichika,Hashimoto, Shouei,Masaki, Yukio
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- Efficient greener methodology for the preparation of bio-based phase change materials from lipids
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In the present work, a new, highly efficient and simple strategy has been developed for the synthesis of long chain esters from fatty acids and fatty alcohols as phase change materials. Equivalent amounts of the selected starting compounds were taken to the esterification reaction at 110 °C in a solventless medium. In order to catalyze the esterification reaction, non-hygroscopic triphenylphosphine-sulfur trioxide adduct was used (0.83 mmol%) which is an easily accessible compound. The relevant reaction was completed in a very short time (2 h) and under optimized esterification conditions, excellent conversion were reached. The targeted mono ester compounds (15 examples) were obtained in good to excellent yields even after a simple crystallization step (72-99%). Additionally, a catalyst reuse investigation and study covering the scale-up production of stearyl stearate was also carried out. The triphenylphosphine-sulfur trioxide catalyzed solvent free process can compete with existing processes and proved to be a cheaper, practical and environmentally-friendly method for the esterification of fatty acids and alcohols.
- Y?ld?r?m, Ayhan,K?raylar, Kaan
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- Solvothermal synthesis of FeCo nanoparticles for magneto-controllable biocatalysis
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A facile and simple one-step solvothermal method has been developed to synthesize FeCo nanoparticles with well-controlled composition, desired morphology and high saturation magnetization, which exhibit component-dependent magnetic behaviors: the increase of Fe content leads to the increase of saturation magnetization and the decrease of coercivity. Furthermore, due to the availability of a coarse surface for the stable adsorption of targeted cargo, the high saturation magnetization for efficient control and directional separation from a reaction mixture by an external magnetic field, the as-prepared magnetic FeCo nanoparticles could work as a fuel-free magneto-controllable carrier to load biocatalytically-active cargo lipase for magneto-controllable and recyclable biocatalytic synthesis of lauryl laurate under an external magnetic field. By alternate positioning of the FeCo carrier with loaded cargo in and out of the substrate solution, the biocatalysis for esterification from lauric acid and lauryl alcohol to lauryl laurate could be switched between "On" and "Off" states.
- Hou, Jianxuan,Kuang, Yun,Shen, Huaqing,Cao, Hui,Luo, Liang,Liu, Junfeng,Wan, Pengbo,Chen, Biqiang,Sun, Xiaoming,Tan, Tianwei
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- Kinetics of the formation of symmetrical wax esters from the corresponding alcohols with the use of hydrobromic acid and hydrogen peroxide
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The primary aliphatic alcohols n-octanol, n-decanol, and n-dodecanol have been converted to their corresponding symmetrical esters by using HBr and H2O2 in the absence of a solvent. The reaction was carried out at 30, 40, and 50°C and at mole ratios of alcohol to HBr of 1:0.1, 1:0.2, 1:0.3, and 1:0.5. The rate of the reaction was found to increase with increase in the reaction temperature and concentration of HBr. The maximal conversion of n-octanol was 72% at 40°C and a mole ratio of n-octanol to HBr of 1:0.5. The kinetics of the reaction have been established, and the reaction was found to be first-order with respect to alcohol and bromine concentration in the organic phase, and second-order with respect to both. The second-order rate constants for n-octanol, n-decanol, and n-dodecanol are 27.08, 32.58, and 37.42 mL mol-1 min-1, respectively, at 40°C. The activation energy for the esterification reaction of n-octanol was found to be 16 32 kcal mol-1.
- Kulkarni,Sawant
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- Mechanistic study of the selective hydrogenation of carboxylic acid derivatives over supported rhenium catalysts
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The structure and performance of TiO2-supported Re (Re/TiO2) catalysts for selective hydrogenation of carboxylic acid derivatives have been investigated. Re/TiO2 promotes selective hydrogenation reactions of carboxylic acids and esters that form the corresponding alcohols, and of amides that generate the corresponding amines. These processes are not accompanied by reduction of aromatic moieties. A Re loading amount of 5 wt% and a catalyst pretreatment with H2 at 500 °C were identified as being optimal to obtain the highest catalytic activity for the hydrogenation processes. The results of studies using various characterization methods, including X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM), indicate that the Re species responsible for the catalytic hydrogenation processes have sub-nanometer to a few nanometer sizes and average oxidation states higher than 0 and below +4. The presence of either a carboxylic acid and/or its corresponding alcohol is critical for preventing the Re/TiO2 catalyst from promoting production of dearomatized byproducts. Although Re/TiO2 is intrinsically capable of hydrogenating aromatic rings, carboxylic acids, alcohols, amides, and amines strongly adsorb on the Re species, which leads to suppression of this process. Moreover, the developed catalytic system was applied to selective hydrogenation of triglycerides that form the corresponding alcohols.
- Toyao, Takashi,Ting, Kah Wei,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Maeno, Zen,Ariga-Miwa, Hiroko,Kanda, Yasuharu,Asakura, Kiyotaka,Shimizu, Ken-ichi
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p. 5413 - 5424
(2019/10/29)
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- PRODUCTION METHOD OF ESTER COMPOUND
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PROBLEM TO BE SOLVED: To produce an ester compound at a high conversion even under mild reaction conditions. SOLUTION: A production method of an ester compound includes a reaction step for reacting a carboxylic acid of 8-22 carbons and an alcohol of 8-22 carbons at a temperature of 50-100°C in an ionic liquid composed of a phosphonium cation or an imidazolium cation and a trifluoromethanesulfonic acid anion or a bis (trifluoromethanesulfonyl) imide anion to obtain an ester compound in a liquid phase different from an ionic liquid phase. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0030; 0033
(2019/10/01)
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- Synthesis of Unsymmetrical N-Heterocyclic Carbene-Nitrogen-Phosphine Chelated Ruthenium(II) Complexes and Their Reactivity in Acceptorless Dehydrogenative Coupling of Alcohols to Esters
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Two novel ruthenium complexes RuH(CO)Cl(PPh3)(κ2-CP) (1) and [fac-RuH(CO)(PPh3)(κ3-CNP)]Cl (2) bearing unsymmetrical N-heterocyclic carbene-nitrogen-phosphine (CNP) were synthesized and characterized with 1H NMR, 31P NMR, and HRMS. The structure of complex 2 was further confirmed by single-crystal X-ray diffraction. An anion exchange experiment proved that complex 2 could transform into complex 1 in solution. The two complexes exhibited a highly catalytic performance in acceptorless dehydrogenative coupling of alcohols to esters, and the excellent isolated yields of esters were given in a catalyst loading of 1% for para- and meta-substituted benzyl alcohols and long-chain primary alcohols. Although some ortho-substituted benzyl alcohols displayed a relatively low reactivity due to the steric hindrance and the coordination of electron donor with the ruthenium center, the good product yields were still obtained by prolonging the reaction time. Especially, this system successfully realized the dehydrogenative cross-coupling to esters between two different primary alcohols.
- He, Xiaochun,Li, Yaqiu,Fu, Haiyan,Zheng, Xueli,Chen, Hua,Li, Ruixiang,Yu, Xiaojun
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p. 1750 - 1760
(2019/04/17)
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- Oxidative esterification of primary alcohols at room temperature under aqueous medium
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Oxidative esterification of aliphatic primary alcohols with bromide and bromate couple in aqueous acidic medium at room temperature is reported with a wide range of substrate scope for both aliphatic and cyclic alcohols and obtained excellent yields of products.
- Reddy, N. Naresh Kumar,Ravi, Chitrakar,Adimurthy, Subbarayappa
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p. 1663 - 1670
(2018/06/15)
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- TiO2-Supported Re as a General and Chemoselective Heterogeneous Catalyst for Hydrogenation of Carboxylic Acids to Alcohols
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TiO2-supported Re, Re/TiO2, was found to promote selective hydrogenation of carboxylic acids having aromatic and aliphatic moieties to the corresponding alcohols. Re/TiO2showed superior results compared to other transition-metal-loaded TiO2and supported Re catalysts for selective hydrogenation of 3-phenylpropionic acid. 3-phenylpropanol was produced in 97 % yield under mild conditions (5 MPa H2at 140 °C). Contrary to typical heterogeneous catalysts, Re/TiO2does not lead to the formation of dearomatized byproducts. The catalyst is recyclable and shows a wide substrate scope in the synthesis of alcohols (22 examples; up to 97 % isolated yield).
- Toyao, Takashi,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Morita, Yoshitsugu,Kamachi, Takashi,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 1001 - 1006
(2017/02/05)
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- Manganese Pincer Complexes for the Base-Free, Acceptorless Dehydrogenative Coupling of Alcohols to Esters: Development, Scope, and Understanding
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Aliphatic PNP pincer-supported earth-abundant manganese(I) dicarbonyl complexes behave as effective catalysts for the acceptorless dehydrogenative coupling of a wide range of alcohols to esters under base-free conditions. The reaction proceeds under neat conditions, with modest catalyst loading and releasing only H2 as byproduct. Mechanistic aspects were addressed by synthesizing key species related to the catalytic cycle (characterized by X-ray structure determination, multinuclear (1H, 13C, 31P, 15N, 55Mn) NMR, infrared spectroscopy, inter alia), by studying elementary steps connected to the postulated mechanism, and by resorting to DFT calculations. As in the case of related ruthenium and iron PNP catalysts, the dehydrogenation results from cycling between the amido and amino-hydride forms of the PNP-Mn(CO)2 scaffold. For the dehydrogenation of alcohols into aldehydes, our results suggest that the highest energy barrier corresponds to the hydrogen release from the amino-hydride form, although its value is close to that of the outer-sphere dehydrogenation of the alcohol into aldehyde. This contrasts with the ruthenium and iron catalytic systems, where dehydrogenation of the substrate into aldehyde is less energy-demanding compared to hydrogen release from the cooperative metal-ligand framework.
- Nguyen, Duc Hanh,Trivelli, Xavier,Capet, Frédéric,Paul, Jean-Fran?ois,Dumeignil, Franck,Gauvin, Régis M.
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p. 2022 - 2032
(2017/08/14)
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- Hydrodeoxygenation of Fatty Acids, Triglycerides, and Ketones to Liquid Alkanes by a Pt–MoOx/TiO2 Catalyst
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Various supported metal catalysts are screened for hydrogenation of lauric acid and 2-octanone as model reactions for the transformation of biomass-derived oxygenates to liquid alkanes (biofuels) in a batch reactor under solvent-free conditions. Among the catalysts tested, Pt and MoOx co-loaded on TiO2 (Pt–MoOx/TiO2) shows the highest yields of n-alkanes for both of the reactions. Pt–MoOx/TiO2 selectively catalyzes the hydrodeoxygenation of various fatty acids and triglycerides to n-alkanes without C?C bond cleavage under 50 bar H2 and shows higher turnover numbers than the catalysts in the literature. Pt–MoOx/TiO2 is effective also for the hydrodeoxygenation of various ketones to the corresponding alkanes. In situ IR study of the reaction of adsorbed acetone under H2 suggests that the high activity of Pt–MoOx/TiO2 is attributed to the cooperation between Pt and Lewis acid sites of the MoOx/TiO2 support.
- Kon, Kenichi,Toyao, Takashi,Onodera, Wataru,Siddiki,Shimizu, Ken-Ichi
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p. 2822 - 2827
(2017/07/28)
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- Transformation of methyl laurate into lauryl alcohol over a Ru-Sn-Mo/C catalyst by using zerovalent iron and water as an in situ hydrogen source
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Hydrogenation and hydrogenolysis reactions, which are used in the chemical industry for the synthesis of organic compounds, are very expensive operations because of the need for facilities that can liquefy, transport, and store the hydrogen produced through steam reforming of natural gas. We have therefore developed a novel approach for hydrogenation that does not require the use of high-cost facilities. Using this, zerovalent iron (Fe) and water (H2O) are introduced as an in situ hydrogen donor system for the transformation of methyl laurate into lauryl alcohol over a Ru-based catalyst. This combination of a Ru-Sn-Mo/C catalyst with a Fe/H2O system showed significantly higher transformation rates for the conversion of methyl laurate into lauryl alcohol than a conventional reaction system that uses pressurized hydrogen. The reason for this is that the new system produces lauric acid as an intermediate during the reaction, which is more efficiently hydrogenized into lauryl alcohol over the Ru-Sn-Mo/C catalyst. The Fe/H2O system played two important roles: a hydrogen source for the hydrogenation reaction and a catalyst for the generation of lauric acid by methyl laurate hydrolysis.
- Sagata, Kunimasa,Hirose, Mina,Hirano, Yoshiaki,Kita, Yuichi
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- Staudinger’s phosphazene as an efficient esterifying reagent
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A new application of Staudinger’s phosphazene as an efficient esterifying reagent is reported. Staudinger’s phosphazene formed in situ by the reaction of organic mono-azide with triphenylphosphine, which is trapped by carboxylic acid, to afford amide exclusively. In contrast, interestingly the same phosphazene behaves in a different way as an efficient esterifying reagent, affording ester under a solvent-free microwave-assisted protocol wherein alcohol is added as the another component in addition to the other reactants. This discovery adds yet another new application of Staudinger’s phosphazene to synthetic chemistry.
- Dinesh, Murugan,Ranganathan, Raja,Archana, Sivasubramaniyan,Sathishkumar, Murugan,Roshan Banu, Mohamed Sulthan,Ponnuswamy, Alagusundaram
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supporting information
p. 1454 - 1460
(2016/09/14)
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- Oxidative esterification of primary alcohols with TEMPO/CaCl2/Oxone under hydrous conditions
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Symmetric esters are important compounds in the chemical industry, which creates demand for simple and efficient synthetic routes. Oxidative esterification is a promising method to achieve these aims. Here, we show that TEMPO/CaCl2/Oxone forms a convenient catalytic system for the synthesis of the aforementioned symmetric esters from primary alcohols in a biphasic dichloromethane-water solvent mixture. The substrate scope of the reaction method is complementary to those previously published and the terminal oxidant appears to play an important role. In addition, the method is shown to oxidize thiols preferentially over alcohol functional groups to give disulfide-bridged compounds.
- Hackbusch, Sven,Franz, Andreas H.
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p. 2873 - 2876
(2016/06/14)
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- Highly efficient self-esterification of aliphatic alcohols using supported gold nanoparticles under mild conditions
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Long aliphatic esters were prepared by the one-step catalytic self-esterification of primary alcohols using molecular oxygen as a green oxidant and supported gold nanoparticles (Au NPs) as catalyst. This heterogeneous catalyst achieved high activity and selectivity in a wide range of less reactive straight-chain alcohols (C4-C12) at atmospheric pressure O2 and near ambient temperature (45?°C). Under optimised conditions, the catalyst with Au loading of 3?wt% achieved the highest catalytic activity and selectivity. The AuNP catalysts are efficient and readily recyclable. The finding of this study may inspire further studies on new efficient catalytic systems for a wide range of organic syntheses using supported AuNP catalysts.
- Wang, Fan,Xiao, Qi,Han, Pengfei,Sarina, Sarina,Zhu, Huaiyong
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- Unprecedented reductive esterification of carboxylic acids under hydrogen by reusable heterogeneous platinum catalysts
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Supported metal catalysts have been tested for an unprecedented reductive dimerization of carboxylic acids to esters under 8 bar hydrogen in solvent-free conditions. Among various metal-loaded tin oxide catalysts, platinum-loaded tin dioxide (Pt/SnO2) shows the highest ester yield for the reaction of dodecanoic acid. Among Pt catalysts on various supports, Lewis acidic oxides, especially SnO2, show high activity. The most active catalyst, 5 wt% Pt/SnO2 reduced at 100°C, is effective for the reductive esterification of various carboxylic acids, and the catalyst is reusable for nine cycles, demonstrating the first successful example for the title reaction. Infrared (IR) studies of a model compound (formic acid) on some metal oxides indicate a strong Lewis acid-base interaction between SnO2 and the carbonyl oxygen. For Pt/SnO2 catalysts with different Pt particle sizes, the activity increases with decreasing size of Pt metal. A cooperative catalysis of the Pt metal nanoparticles and the Sn4+ Lewis acid sites is proposed.
- Touchy, Abeda S.,Kon, Kenichi,Onodera, Wataru,Shimizu, Ken-Ichi
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p. 1499 - 1506
(2015/05/19)
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- Hydrodeoxygenation of fatty acids and triglycerides by Pt-loaded Nb2O5catalysts
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Platinum nanoparticles loaded onto various supports have been studied for the selective hydrogenation of lauric acid to n-dodecane. The activity depends on the support material and pre-reduction temperature. Pt/Nb2O5reduced at 300 °C gives the highest activity. Pt/Nb2O5shows higher activity than various Nb2O5-supported transition metals (Ir, Re, Ru, Pd, Cu, Ni). Under solvent-free conditions Pt/Nb2O5is effective for the hydrodeoxygenation of lauric, capric, palmitic, myristic, oleic, and stearic acids under 8 bar H2at 180-250 °C, which gives high yields (88-100%) of linear alkanes with the same chain length as the starting compound. Tristearin is also converted to give 93% yield of n-octadecane. Pt/Nb2O5shows more than 60 times higher turnover number (TON) than the previously reported catalysts for the hydrogenation of stearic acid to n-octadecane. Mechanistic study shows a consecutive reaction pathway in which lauric acid is hydrogenated to 1-dodecanol, which undergoes esterification with lauric acid as well as hydrogenation to n-dodecane. The ester undergoes hydrogenolysis to give the alcohol, which is hydrogenated to the alkane. Infrared (IR) study of acetic acid adsorption on Nb2O5indicates that Lewis acid-base interaction of Nb cation and carbonyl oxygen, which suggests a possible role of Nb2O5as an activation site of carbonyl groups during hydrodeoxygenation. This journal is
- Kon, Kenichi,Onodera, Wataru,Takakusagi, Satoru,Shimizu, Ken-Ichi
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p. 3705 - 3712
(2015/04/14)
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- Promotional effect of Fe on performance of Ni/SiO2 for deoxygenation of methyl laurate as a model compound to hydrocarbons
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Ni/SiO2, Fe/SiO2 and bimetallic FeNi/SiO2 catalysts with different Fe/Ni weight ratios were prepared by incipient-wetness impregnation method for the deoxygenation of methyl laurate to hydrocarbons. It was found that a suitable amount of Fe enhanced the activity of Ni/SiO2 for the deoxygenation of methyl laurate, and FeNi(0.25)/SiO2 with a Fe/Ni weight ratio of 0.25 showed the best activity. Moreover, the addition of Fe to Ni/SiO2 significantly promoted the hydrodeoxygenation pathway to produce more C12 hydrocarbon and suppressed the activity for C-C hydrogenolysis. The effect of Fe on the performance of Ni/SiO2 is ascribed the formation of the NiFe alloy particles, particularly with the Fe-enriched surface at low Fe content, and the existence of oxygen vacancies in Fe oxides. A mechanism is proposed to explain the promoting effect of Fe, which involves the synergism between iron sites with strong oxophilicity and nickel sites with high ability to activate hydrogen. Besides, the effect of reaction conditions and catalyst stability were also investigated.
- Yu, Xinbin,Chen, Jixiang,Ren, Tianyu
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p. 46427 - 46436
(2015/01/09)
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- PROCESS FOR MAKING LINEAR LONG CHAIN ALKANES USING RENEWABLE FEEDSTOCKS
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A hydrodeoxygenation process for producing a linear alkane from a feedstock comprising a saturated or unsaturated C10-18 oxygenate that comprises an ester group, carboxylic acid group, carbonyl group and/or alcohol group is disclosed. The process comprises contacting the feedstock with a catalyst comprising (i) about 0.1% to 10% by weight of a metal selected from Group IB or VIII of the Periodic Table, and (ii) about 0.5% to 15% by weight of tungsten, rhenium, molybdenum, vanadium, manganese, zinc, chromium, germanium, tin, titanium, gold, and/or zirconium, at a temperature between about 150° C. to 250° C. and a hydrogen gas pressure of at least 300 psig. By contacting the feedstock with the catalyst under these temperature and pressure conditions, the C10-18 oxygenate is hydrodeoxygenated to a linear alkane that has the same carbon chain length as the C10-18 oxygenate.
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Paragraph 0103-0110
(2014/04/03)
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- PROCESS FOR MAKING LINEAR LONG-CHAIN ALKANES FROM RENEWABLE FEEDSTOCKS USING CATALYSTS COMPRISING HETEROPOLYACIDS
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A hydrodeoxygenation process for producing a linear alkane from a feedstock comprising a saturated or unsaturated C10-18 oxygenate that comprises an ester group, carboxylic acid group, carbonyl group and/or alcohol group is disclosed. This process comprises contacting the feedstock with (i) a catalyst comprising about 0.1 % to about 10% by weight of a metal selected from Group IB, VIB, or VIII of the Periodic Table, and (ii) a heteropolyacid or heteropolyacid salt, at a temperature between about 150 °C to about 250 °C and a hydrogen gas pressure of at least about 300 psig. By contacting the feedstock with the catalyst and heteropolyacid or heteropolyacid salt under these temperature and pressure conditions, the C10-18 oxygenate is hydrodeoxygenated to a linear alkane that has the same carbon chain length as the C10-18 oxygenate.
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Page/Page column 33; 34; 35
(2014/10/15)
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- Sulfonated polypyrene (S-PPR) as efficient catalyst for esterification of carboxylic acids with equimolar amounts of alcohols without removing water
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Sulfonated polypyrene (S-PPR) efficiently catalyzed the reactions between carboxylic acids and equimolar amounts of alcohols with and without heptane to give the corresponding esters in good to excellent yields. Esterification was carried out at 110 °C without removing water. Transesterification of carboxylic esters with a slight excess of alcohols smoothly proceeded without heptane to give the corresponding esters in good yields. For these reactions, S-PPR was recycled without significant loss of activities.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
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p. 1972 - 1975
(2013/04/23)
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- Improving the activity and stability of Yarrowia lipolytica lipase Lip2 by immobilization on polyethyleneimine-coated polyurethane foam
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In this study, polyurethane foam (PUF) was used for immobilization of Yarrowia lipolytica lipase Lip2 via polyethyleneimine (PEI) coating and glutaraldehyde (GA) coupling. The activity of immobilized lipases was found to depend upon the size of the PEI polymers and the way of GA treatment, with best results obtained for covalent-bind enzyme on glutaraldehyde activated PEI-PUF (MW 70,000 Da), which was 1.7 time greater activity compared to the same enzyme immobilized without PEI and GA. Kinetic analysis shows the hydrolytic activity of both free and immobilized lipases on triolein substrate can be described by Michaelis-Menten model. The Km for the immobilized and free lipases on PEI-coated PUF was 58.9 and 9.73 mM, respectively. The Vmax values of free and immobilized enzymes on PEI-coated PUF were calculated as 102 and 48.6 U/mg enzyme, respectively. Thermal stability for the immobilization preparations was enhanced compared with that for free preparations. At 50 C, the free enzyme lost most of its initial activity after a 30 min of heat treatment, while the immobilized enzymes showed significant resistance to thermal inactivation (retaining about 70% of its initial activity). Finally, the immobilized lipase was used for the production of lauryl laurate in hexane medium. Lipase immobilization on the PEI support exhibited a significantly improved operational stability in esterification system. After re-use in 30 successive batches, a high ester yield (88%) was maintained. These results indicate that PEI, a polymeric bed, could not only bridge support and immobilized enzymes but also create a favorable micro-environment for lipase. This study provides a simple, efficient protocol for the immobilization of Y. lipolytica lipase Lip2 using PUF as a cheap and effective material.
- Cui, Caixia,Tao, Yifeng,Li, Lingli,Chen, Biqiang,Tan, Tianwei
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- Oxidant controlled Pd-catalysed selective oxidation of primary alcohols
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The oxidant controlled palladium catalysed selective oxidation of primary alcohols to aldehydes or esters was investigated. The electronic properties of the benzylic alcohols and the structure of the oxidant are both important factors in controlling the selectivity between aldehydes and esters. A covalent benzyl ligand derived from BnCl provides η3 coordination to the Pd centre. This covalent ligand is the key to the selective oxidative esterification of primary alcohols.
- Liu, Chao,Tang, Shan,Lei, Aiwen
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supporting information
p. 1324 - 1326
(2013/03/13)
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- Efficient dimeric esterification of alcohols with NBS in water using l-proline as catalyst
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The L-proline-catalyzed oxidation of aliphatic primary alcohols with N-bromosuccimide (NBS) in water at room temperature to afford the corresponding dimeric esters in good to excellent yields was described. This pathway of dimeric esterification was proved to be very simple and environmentally friendly.
- Liu, Xiuhong,Wu, Jun,Shang, Zhicai
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experimental part
p. 75 - 83
(2011/11/05)
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- DEHYDRATING CONDENSATION AGENT HAVING PROPERTY OF ACCUMULATING AT INTERFACE WITH WATER
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The present invention provides a 1,3,5-triazine compound represented by the following formula I: This compound can be synthesized easily and more economically and can be used as a dehydrating condensing agent having the property of accumulating at a water interface. In the case where carboxylic acid, amine, alcohol or other reaction substrate is amphiphilic, when mixing the dehydrating condensing agent of the present invention, which is amphiphilic, and the substrate to form various molecular aggregate phase including micelles in an aqueous solution, the substrate and the dehydrating condensing agent can be accumulated at the water interface. As a result, the concentration of the substrate increases locally at the water interface, and condensation reaction can be performed extremely efficiently.
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Page/Page column 17
(2008/06/13)
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- Oxidative dimerization of primary alcohols to esters catalyzed by iridium complexes
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Primary alcohols undergo efficiently oxidative dimerization by iridium complexes under air without any solvent to form esters in fair to good yields. For instance, the reaction of 1-dodecanol in the presence of [IrCl(coe)2]2 (3 mol %) at 95 °C for 15 h produced dodecyl dodecanoate in 91% isolated yield. This is the first successful Ir-catalyzed oxidative dimerization of primary alcohols to esters using air as an oxidant. Various primary alcohols are converted to the corresponding esters in fair to good yields.
- Izumi, Aki,Obora, Yasushi,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 9199 - 9201
(2007/10/03)
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- "Nafion"-functionalized mesoporous MCM-41 silica shows high activity and selectivity for carboxylic acid esterification and Friedel-Crafts acylation reactions
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Hybrid organic-inorganic MCM-41 silicas functionalized with perfluoroalkylsulfonic acid groups analogous to that of Nafion were prepared in a simple single step by a condensation reaction between surface silanol groups of the mesoporous silicas and 1,2,2-trifluoro-2-hydroxy-1-trifluoromethyl-ethane sulfonic acid Beta-sultone. The catalysts showed very high activity for the esterification of long-chain fatty acids with ethanol and high-molecular-weight alcohols with essentially complete selectivity at high conversion (>95%). Acylation of anisole was also possible, with high selectivity for 4-methoxyacetophenone. The catalysts showed more activity conversion than commercial Nafion-silica composite catalysts.
- Alvaro, Mercedes,Corma, Avelino,Das, Debasish,Fornes, Vicente,Garcia, Hermenegildo
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- Process for producing esters employing hydrolyzable catalysts
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A process for producing esters wherein a carboxylic acid is reacted with an alcohol in the presence of a hydrolyzable catalyst in an aqueous medium under mixing to produce a reaction mixture comprising an organic phase containing ester and an aqueous phase.
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Page/Page column 5
(2008/06/13)
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- An improved greener esterification of fatty alcohols using a renewable acid-ionic liquid couple as catalyst-solvent
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We have developed a simple and efficient method for the esterification of various organic acids with C4-C18 alcohols using the 1-octyl-3-methyl- imidazolium tetrafluoroborate-para-toluenesulphonic acid (OMIM/BF 4-PTSA) couple, without organic solvent, either by classic heating or by microwave irradiation. The utilisation of the OMIM/BF4-PTSA couple presents considerable advantages: high yield, low temperature, short reaction time, isolation of the ester by simple decantation, easy reuse of the catalyst couple.
- Nguyen, Hoang-Phuong,Znifeche, Samira,Baboulene, Michel
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p. 2085 - 2093
(2007/10/03)
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- Effect of Ionic Liquids on the Chemical Equilibrium of Esterification of Carboxylic Acids with Alcohols
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The esterification of carboxylic acids with alcohols catalyzed by paratoluene sulfonic acid (pTSA) was studied in different room temperature ionic liquids. The chemical equilibrium of esterification can be tuned by using ionic liquids as solvents.
- Jiang, Tao,Chang, Yanhong,Zhao, Guoying,Han, Buxing,Yang, Guanying
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p. 225 - 230
(2007/10/03)
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- Esterification of aldehydes and alcohols with pyridinium hydrobromide perbromide in water
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The direct esterification of aldehydes and alcohols was carried out with pyridinium hydrobromide perbromide in water at room temperature. A variety of aldehydes were converted to respective ester derivatives with alcohols such as methanol, 1,2-ethanediol, 1,3-propanediol. Further, a variety of aliphatic alcohols were also converted to the corresponding Tishchenko-like dimeric esters in good yields under the same reaction conditions.
- Sayama, Shinsei,Onami, Tetsuo
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p. 2739 - 2745
(2007/10/03)
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- Remarkable reactivity of pyridinium chlorochromate adsorbed on neutral alumina under solvent-free conditions
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Pyridinium chlorochromate adsorbed on neutral alumina (PCC-Al2O3) under solvent-free conditions has been found to oxidize primary aliphatic alcohols to alkyl alkanoates whereas primary benzylic and primary allylic alcohols produce the corresponding aldehydes. Secondary aliphatic and aromatic alcohols produce ketones without isomerization and polymerization of double bonds, overoxidation and other side-reactions.
- Bhar, Sanjay,Chaudhuri, Subrata Kumar
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p. 3493 - 3498
(2007/10/03)
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- Facile and efficient oxidative transformation of primary alcohols to methyl esters in water using hypervalent iodine(III) reagents
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A facile and direct oxidative esterification of primary alcohols in water using a combination of the hypervalent iodine(III) reagent, iodosobenzene (PhIO), and KBr has been developed. This methodology is expected to be environmentally benign since it uses a recyclable polymer-supported iodine(III) reagent in water.
- Tohma, Hirofumi,Maegawa, Tomohiro,Kita, Yasuyuki
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p. 723 - 725
(2007/10/03)
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- Process for preparation of an ester using a polyaniline salt as catalyst
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The invention relates to a process for preparation of an ester using a polyaniline salt as catalyst.
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- Dehydration reactions in water. Bronsted acid-surfactant-combined catalyst for ester, ether, thioether, and dithioacetal formation in water
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Dehydration reactions in water have been realized by a surfactant-type catalyst, dodecylbenzenesulfonic acid (DBSA). These reactions include dehydrative esterification, etherification, thioetherification, and dithioacetalization. In these reactions, DBSA and substrates form emulsion droplets whose interior is hydrophobic enough to exclude water molecules generated during the reactions. Detailed studies on the esterification revealed that the yields of esters were affected by temperature, amounts of DBSA used, and the substrates. Esters were obtained in high yields for highly hydrophobic substrates. On the basis of the difference in hydrophobicity of the substrates, unique selective esterification and etherification in water were attained. Furthermore, chemospecific, three-component reactions under DBSA-catalyzed conditions were also found to proceed smoothly. This work not only may lead to environmentally benign systems but also will provide a new aspect of organic chemistry in water.
- Manabe, Kei,Iimura, Shinya,Sun, Xiang-Min,Kobayashi, Shu
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p. 11971 - 11978
(2007/10/03)
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- Thermodynamics of the lipase-catalyzed esterification of 1-dodecanoic acid and 1-dodecanol in organic solvents
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Lipase immobilized on controlled-pore glass beads was used to catalyze the esterification of 1-dodecanol and 1-dodecanoic acid in organic solvents. Equilibrium measurements were performed in hexane, heptane, cyclohexane, 2,2,4-trimethylpentane, and toluene at the temperature T = 298.15 K. The equilibrium constants correlate well with the (octanol+water) partition coefficients and the dielectric constants of the solvents. The saturation molalities and the (2,2,4-trimethylpentane+water) partition coefficients of 1-dodecanol, 1-dodecanoic acid, and dodecyl dodecanoate have been determined at T = 298.15 K. The equilibrium constant of the esterification reaction in water has also been calculated.
- Tewari
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p. 750 - 755
(2007/10/03)
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- Mild esterification and transesterification of carboxylic acids catalyzed by tetracyanoethylene and dicyanoketene dimethyl acetal
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A π-acid tetracyanoethylene (TCNE) and its derivative dicyanoketene dimethyl acetal (DCKDMA) were found to catalyze esterification of lauric acid with various types of alcohols. This method was successfully applied to methyl esterification of a variety of carboxylic acids including aromatic, α,β-unsaturated, α-hydroxy, and N-Cbz and N-Boc-protected α-amino acids without racemization at the range from room temperature to 60 °C. TCNE was also found to operate as a catalyst in transeslerification reaction of methyl laurate.
- Masaki, Yukio,Tanaka, Nobuyuki,Miura, Tsuyoshi
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- Homolytic Transformations of Alkyl Hypochlorites into Esters
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Alkyl hypochlorites under UV irraduation at room temperature are selectively transformed into the corresponding esters. The reaction can be applied to preparation of higher esters. Free radical chain mechanism of products formation was presumed including intermediate aldehydes and acyl radicals. Under the same conditions aldehydes readily react with alkyl hypochlorites to yield esters.
- Zorin,Bikbulatov,Zorina,Rakhmankulov
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p. 453 - 456
(2007/10/03)
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- Fatty methyl ester hydrogenation to fatty alcohol Part II: Process issues
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Fatty alcohols are produced by hydrogenating fatty methyl esters in slurry phase in the presence of copper chromite catalyst at temperatures of 250-300 °C and hydrogen pressures of 2000-3000 psi. The fatty methyl ester, catalyst, and hydrogen are fed to the reactor cocurrently. The product slurry is passed through gas-liquid separators and then through a continuous filtration system for removal of the catalyst. A portion of the used catalyst in crude alcohol is recycled to the hydrogenator. The overall efficiency of the process depends upon the intrinsic activity, life, and filterability of the catalyst. The fatty alcohol producer therefore requires a catalyst with high activity, long life, and good separation properties. The main goal of the present laboratory investigation was to develop a superior copper chromite catalyst for the slurry-phase process. Two copper chromite catalysts, prepared by different procedures, were tested for methyl ester hydrogenolysis activity, reusability, and filtration characteristics. The reaction was carried out in a batch autoclave at 280 °C and 2000-3000 psi hydrogen pressure. The reaction rates were calculated by assuming a kinetic mechanism that was first-order in methyl ester concentration. The catalyst with the narrower particle size distribution was 30% more active, filtered faster, and maintained activity for several more uses than the catalyst with the broader particle size distribution. X-ray photoelectron spectroscopy data showed higher surface copper concentrations for the former catalyst.
- Rieke,Thakur,Roberts,White
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p. 341 - 345
(2007/10/03)
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- Fatty methyl ester hydrogenation to fatty alcohol part I: Correlation between catalyst properties and activity/selectivity
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Fatty alcohols, derived from natural sources, are commercially produced by hydrogenation of fatty acids or methyl esters in slurry-phase or fixed-bed reactors. One slurry-phase hydrogenation of methyl ester process flows methyl esters and powdered copper chromite catalyst into tubular reactors under high hydrogen pressure and elevated temperature. In the present investigation, slurry-phase hydrogenations of C12 methyl ester were carried out in semi-batch reactions at non-optimal conditions (i.e., low hydrogen pressure and elevated temperature). These conditions were used to accentuate the host of side reactions that occur during the hydrogenation. Some 14 side reaction routes are outlined. As an extension of this study, copper chromite catalyst was produced under a number of varying calcination temperatures. Differences in catalytic activity and selectivity were determined by closely following side reaction products. Both activity and selectivity correlate well with the crystallinity of the copper chromite surface; they increase with decreasing crystallinity. The ability to follow the wide variety of side reactions may well provide an additional tool for the optimized design of hydrogenation catalysts.
- Rieke, Ross D.,Thakur, Deepak S.,Roberts, Brian D.,White, Geoffrey T.
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p. 333 - 339
(2007/10/03)
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- Oxidation of primary alcohols to acyl fluorides using BrF3
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Aliphatic and alicyclic primary alcohols when treated with BrF3 were rapidly oxidized to the corresponding acyl fluorides. The reaction is of an ionic nature. The main by-product was found to be the symmetrical ester which originates from the reaction between the acyl fluoride and unreacted starting alcohol.
- Rozen, Shlomo,Ben-David, Iris
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p. 145 - 147
(2007/10/03)
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- Oxidation Using Quaternary Ammonium Polyhalides. III. An Effective Oxidation of Alcohols and Ethers by the Use of Benzyltrimethylammonium Tribromide
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The reaction of primary alcohols or simple ethers and α,ω-diols or cyclic ethers with a stoichiometric amount of benzyltrimethylammonium tribromide (BTMA) Br3) in carbon tetrachloride in the presence of Na2HPO4 aq or in acetic acid in the presence of CH3CO2Na aq at 60-70 deg C gave dimeric esters and lactones respectively in good yields.The reaction of secondary alcohols with 1 equiv of BTMA Br3 in the presence of a buffer at 60 deg C gave ketones.
- Kajigaeshi, Shoji,Kawamukai, Hiroshi,Fujisaki, Shizuo
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p. 2585 - 2588
(2007/10/02)
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- Fat Hydrolysis and Esterification by a Lipase from Humicola lanuginosa
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The hydrolysis and esterification by a thermostable lipase from Humicola lanuginosa No. 3 were investigated.Both reactions occurred readily at temperatures between 45-50 deg C.Esterification by the enzyme with glycerol was observed to be specific towards fatty acids with carbon numbers of C12-C18.Lauric acid esters with different alcohols such as primary alcohols, terpene alcohols, etc., were also synthesized readily.Esterification by the enzyme was adversely affected by the water content (optimum, ca. 7percent), however, the hydrolysis rate increased rapidly with increasing water content (optimum, ca. 60percent).The enzyme showed increased activity in organic solvent-aqueous reaction systems.Nevertheless, hydrolysis in complete organic phase reactions was found not to be feasible.Hydrolysis at a higher temperature (50 or 55 deg C) in a solvent free phase was almost the same as that in organic solvent-aqueous phase reactions.The components of glycerides varied considerably during hydrolysis, whereby esterification resulted in a higher quantity of mono- and diglycerides (about 40percent), compared to in the case of hydrolysis, for which the value was about 10-20percent.
- Omar, Ibrahim Che,Nishio, Naomichi,Nagai, Shiro
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p. 2153 - 2160
(2007/10/02)
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- Cerium or Ruthenium Catalyzed Oxidation of Alcohols to Carbonyl Compounds by Means of Sodium Bromate
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Sodium bromate has been found to be effective oxidant for oxidation of alcohols in the presence of cerium or ruthenium compounds in biphase reaction.Selective oxidation of secondary alcohols was performed in the presence of primary ones using cerium(IV) ammonium nitrate (CAN) or cerium(IV) sulfate (CS) as catalyst.For instance, treatment of 1,10-undecanediol with CS/NaBrO3 provided 11-hydroxy-2-undecanone in 82percent yield.Ruthenium catalyzed biphase oxidation of alcohols with sodium bromate provided the corresponding aldehydes or ketones in good to excellent yields.
- Kanemoto, Shigekazu,Tomioka, Hiroki,Oshima, Koichiro,Nozaki, Hitosi
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p. 105 - 108
(2007/10/02)
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