- Synthesis of the enantiomer of the antidepressant tranylcypromine
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Both enantiomers of the antidepressant tranylcypromine, trans 2-phenyl-cyclopropylamine 1, were prepared in enantiomerically pure form by a chemoenzymatic approach starting from racemic (±)-(1RS, 2RS)-trans ethyl 2-phenyl-cyclopropane carboxylate (±)-3.
- Csuk, Rene,Schabel, Magda J.,Von Scholz, Yvonne
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Read Online
- Continuous-Flow Reductive Alkylation: Synthesis of Bio-based Symmetrical and Disymmetrical Ethers
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For the first time, a reductive alkylation process in continuous flow has been elaborated for the conversion of bio-based alcohols and aldehydes into symmetrical and dissymmetrical high-value-added ethers for industrial companies. The developed method is an etherification associating liquid, solid and gas phases under green conditions (continuous flow, catalysis, bio-based starting materials).
- Bruniaux, Sophie,Luart, Denis,Len, Christophe
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Read Online
- Conversion of 1-hexanol to di-n-hexyl ether on acidic catalysts
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Conversion, selectivity and yield of 1-hexanol liquid phase dehydration to di-n-hexyl ether (DNHE) were determined at 150-190 °C on three acidic catalysts, the thermally stable resin Amberlyst 70, the perfluoroalkanesulfonic Nafion NR50 and the zeolite H-BEA-25, in a batch reactor. The highest conversion and yield were achieved on Amberlyst 70 at 190 °C, but the most selective catalyst was Nafion NR50. Good results were obtained at 190 °C on the zeolite. Apparent activation energies for the three catalysts were in the range 108-140 kJ/mol. Unlike H-BEA-25, the reaction of DNHE synthesis on Amberlyst 70 and NR50 was a bit more active but less selective than the analogous 1-pentanol dehydration to di-n-pentyl ether (DNPE).
- Medina, Eduardo,Bringué, Roger,Tejero, Javier,Iborra, Montserrat,Fité, Carles
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Read Online
- Novel application of a solid super acid, sulfated zirconia, as a catalyst for Koch carbonylation reaction
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A solid superacid, sulfated zirconia, worked well in the Koch reaction. Under optimized conditions, tertiary alcohols were selectively transformed to the corresponding carboxylic acids (34-72%), while primary alcohols were transformed to the corresponding ethers (58-72%).
- Mori, Hajime,Wada, Aya,Xu, Qiang,Souma, Yoshie
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Read Online
- Synthesis of ethyl hexyl ether over acidic ion-exchange resins for cleaner diesel fuel
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The synthesis of ethyl hexyl ether as a suitable diesel additive was investigated using 1-hexanol and diethyl carbonate as reactants and acidic ion-exchange resins as catalysts. Liquid-phase experiments were performed in a batch reactor at the temperature range of 403-463 K and 2.5 MPa. The formation of ethyl hexyl ether proceeded from two routes: thermal decomposition of ethyl hexyl carbonate and intermolecular dehydration of 1-hexanol with ethanol. Both pathways require a previous transesterification reaction between diethyl carbonate and 1-hexanol. It was revealed that this reaction is favoured in polymer zones of 0.4 nm nm-3 polymer density (equivalent to 2.6 nm diameter pores in inorganic materials). Acidic ion-exchange resins containing a significant volume fraction of this polymer density are Dowex 50W×2 and Amberlyst 70. By using this kind of catalyst, reaction rate and selectivity are significantly increased. Finally, it was observed that working at low temperature would favour the selectivity to ethyl hexyl carbonate and hinder the undesired formation of alkenes. This journal is
- Guilera,Ramírez,Fité,Tejero,Cunill
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Read Online
- PROCESSES FOR PRODUCING ALCOHOLS FROM BIOMASS AND FURTHER PRODUCTS DERIVED THEREFROM
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Processes for producing alcohols from biomass are provided. The processes utilize supercritical methanol to depolymerize biomass with subsequent conversion to a mixture of alcohols. In particular the disclosure relates to continuous processes which produce high yields of alcohols through recycling gases and further employ dual reactor configurations which improve overall alcohol yields. Processes for producing higher ethers and olefins from the so-formed alcohols, through alcohol coupling and subsequent dehydration are also provided. The resulting distillate range ethers and olefins are useful as components in liquid fuels, such as diesel and jet fuel.
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Paragraph 0530-0534
(2021/11/26)
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- Uranyl(VI) Triflate as Catalyst for the Meerwein-Ponndorf-Verley Reaction
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Catalytic transformation of oxygenated compounds is challenging in f-element chemistry due to the high oxophilicity of the f-block metals. We report here the first Meerwein-Ponndorf-Verley (MPV) reduction of carbonyl substrates with uranium-based catalysts, in particular from a series of uranyl(VI) compounds where [UO2(OTf)2] (1) displays the greatest efficiency (OTf = trifluoromethanesulfonate). [UO2(OTf)2] reduces a series of aromatic and aliphatic aldehydes and ketones into their corresponding alcohols with moderate to excellent yields, using iPrOH as a solvent and a reductant. The reaction proceeds under mild conditions (80 °C) with an optimized catalytic charge of 2.3 mol % and KOiPr as a cocatalyst. The reduction of aldehydes (1-10 h) is faster than that of ketones (>15 h). NMR investigations clearly evidence the formation of hemiacetal intermediates with aldehydes, while they are not formed with ketones.
- Kobylarski, Marie,Monsigny, Louis,Thuéry, Pierre,Berthet, Jean-Claude,Cantat, Thibault
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supporting information
p. 16140 - 16148
(2021/11/01)
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- Catalytic reductive deoxygenation of esters to ethers driven by hydrosilane activation through non-covalent interactions with a fluorinated borate salt
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We report the catalytic and transition metal-free reductive deoxygenation of esters to ethers through the use of a hydrosilane and a fluorinated borate BArF salt as a catalyst. Experimental and theoretical studies support the role of noncovalent interactions between the fluorinated catalyst, the hydrosilane and the ester substrate in the reaction mechanism.
- Agbossou-Niedercorn, Francine,Dixit, Ruchi,Merle, Nicolas,Michon, Christophe,Rysak, Vincent,Trivelli, Xavier,Vanka, Kumar
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p. 4586 - 4592
(2020/08/14)
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- Novel Si(II)+and Ge(II)+Compounds as Efficient Catalysts in Organosilicon Chemistry: Siloxane Coupling Reaction ?
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Novel catalytically active cationic Si(II) and Ge(II) compounds were synthesized and isolated in pure form. The Ge(II)+-based compounds proved to be stable against air and moisture and therefore can be handled very easily. All compounds efficiently catalyze the oxidative coupling of hydrosil(ox)anes with aldehydes and ketones as oxidation reagents and simultaneously the reductive ether coupling at very low amounts of 0.01 mol %. Because the catalysts also catalyze the reversible cyclotrimerization of aldehydes, paraldehyde can be used as a convenient source for acetaldehyde in siloxane coupling. It is shown that the reaction is especially suitable to make siloxane copolymers. Moreover, a new fluorine-free weakly coordinating boronate anion, B(SiCl3)4-, was successfully combined with the Si(II) and Ge(II) cations to give the stable catalytically active ion pairs Cp*Si:+B(SiCl3)4-, Cp*Ge:+B(SiCl3)4-, and [Cp(SiMe3)3Ge:+]B(SiCl3)4-.
- Fritz-Langhals, Elke,Kneissl, Sotirios,Piroutek, Phillip,Werge, Sven
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- Multistep Engineering of Synergistic Catalysts in a Metal-Organic Framework for Tandem C-O Bond Cleavage
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Cleavage of strong C-O bonds without breaking C-C/C-H bonds is a key step for catalytic conversion of renewable biomass to hydrocarbon feedstocks. Herein we report multistep sequential engineering of orthogonal Lewis acid and palladium nanoparticle (NP) catalysts in a metal-organic framework (MOF) built from (Al-OH)n secondary building units and a mixture of 2,2′-bipyridine-5,5′-dicarboxylate (dcbpy) and 1,4-benzenediacrylate (pdac) ligands (1) for tandem C-O bond cleavage. Ozonolysis of 1 selectively removed pdac ligands to generate Al2(OH)(OH2) sites, which were subsequently triflated with trimethylsilyl triflate to afford strongly Lewis acidic sites for dehydroalkoxylation. Coordination of Pd(MeCN)2Cl2 to dcbpy ligands followed by in situ reduction produced orthogonal Pd NP sites in 1-OTf-PdNP as the hydrogenation catalyst. The selective and precise transformation of 1 into 1-OTf-PdNP was characterized step by step using powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, inductively coupled plasma mass spectrometry, infrared spectroscopy, and X-ray absorption spectroscopy. The hierarchical incorporation of orthogonal Lewis acid and Pd NP active sites endowed 1-OTf-PdNP with outstanding catalytic performance in apparent hydrogenolysis of etheric, alcoholic, and esteric C-O bonds to generate saturated alkanes via a tandem dehydroalkoxylation-hydrogenation process under relatively mild conditions. The reactivity of C-O bonds followed the trend of tertiary carbon > secondary carbon > primary carbon. Control experiments demonstrated the heterogeneous nature and recyclability of 1-OTf-PdNP and its superior catalytic activity over the homogeneous counterparts. Sequential engineering of multiple catalytic sites in MOFs thus presents a unique opportunity to address outstanding challenges in sustainable catalysis.
- Brzezinski, Carter,Chen, Justin S.,Feng, Xuanyu,Lin, Wenbin,Song, Yang,Xu, Ziwan
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supporting information
p. 4872 - 4882
(2020/04/01)
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- PROCESS
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A process for dehydrating C2+ alcohols to ether products in the presence of a catalyst and promoter, wherein the catalyst is at least one aluminosilicate zeolite catalyst which is a medium pore zeolite having a 3-dimensional framework structure, and the promoter is one or more organic carbonyl compounds or derivatives thereof, and wherein and the molar ratio of promoter to C2+ alcohols is maintained at less than 1.
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Page/Page column 31-32
(2020/09/08)
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- Breaking C-O Bonds with Uranium: Uranyl Complexes as Selective Catalysts in the Hydrosilylation of Aldehydes
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We report herein the possibility to perform the hydrosilylation of carbonyls using actinide complexes as catalysts. While complexes of the uranyl ion [UO2]2+ have been poorly considered in catalysis, we show the potentialities of the Lewis acid [UO2(OTf)2] (1) in the catalytic hydrosilylation of a series of aldehydes. [UO2(OTf)2] proved to be a very active catalyst affording distinct reduction products depending on the nature of the reductant. With Et3SiH, a number of aliphatic and aromatic aldehydes are reduced into symmetric ethers, while iPr3SiH yielded silylated alcohols. Studies of the reaction mechanism led to the isolation of aldehyde/uranyl complexes, [UO2(OTf)2(4-Me2N-PhCHO)3], [UO2(μ-κ2-OTf)2(PhCHO)]n, and [UO2(μ-κ2-OTf)(κ1-OTf)(PhCHO)2]2, which have been fully characterized by NMR, IR, and single-crystal X-ray diffraction.
- Monsigny, Louis,Thuéry, Pierre,Berthet, Jean-Claude,Cantat, Thibault
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p. 9025 - 9033
(2019/10/02)
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- Synthesis of Benzyl Alkyl Ethers by Intermolecular Dehydration of Benzyl Alcohol with Aliphatic Alcohols under the Effect of Copper Containing Catalysts
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Synthesis of benzyl alkyl ethers was performed in high yields by intermolecular dehydration of benzyl and primary, secondary, tertiary alcohols under the effect of copper containing catalysts. The formation of benzyl alkyl ethers occurs with participation of benzyl cation.
- Bayguzina,Gimaletdinova,Khusnutdinov
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p. 1148 - 1155
(2018/10/24)
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- Effect of Alcohol Structure on the Kinetics of Etherification and Dehydration over Tungstated Zirconia
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Linear and branched ether molecules have attracted recent interest as diesel additives and lubricants that can be produced from biomass-derived alcohols. In this study, tungstated zirconia was identified as a selective and green solid acid catalyst for the direct etherification of primary alcohols in the liquid phase, achieving ether selectivities of >94 % for C6–C12 linear alcohol coupling at 393 K. The length of linear primary alcohols (C6–C12) was shown to have a negligible effect on apparent activation energies for etherification and dehydration, demonstrating the possibility to produce both symmetrical and asymmetrical linear ethers. Reactions over a series of C6 alcohols with varying methyl branch positions indicated that substituted alcohols (2°, 3°) and alcohols with branches on the β-carbon readily undergo dehydration, but alcohols with branches at least three carbons away from the -OH group are highly selective to ether. A novel model compound, 4-hexyl-1dodecanol, was synthesized and tested to further demonstrate this structure–activity relationship. Trends in the effects of alcohol structure on selectivity were consistent with previously proposed mechanisms for etherification and dehydration, and help to define possible pathways to selectively form ethers from biomass-derived alcohols.
- Rorrer, Julie,Pindi, Suresh,Toste, F. Dean,Bell, Alexis T.
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p. 3104 - 3111
(2018/09/06)
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- Synthesis of ethers from carbonyl compounds by reductive etherification catalyzed by iron(III) and silyl chloride
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A simple iron- and silyl chloride catalyzed method for the preparation of symmetrical and nonsymmetrical ethers is presented. Various aldehydes and ketones were reductively etherified by using triethylsilane as a reducing agent in the presence of 2 mol% of iron(III) oxo acetate and 8 mol% of chloro(trimethyl)silane. The reactions can be carried out at ambient temperatures and pressures with ethyl acetate as the solvent.
- Savela, Risto,Leino, Reko
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p. 1749 - 1760
(2015/06/16)
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- Organohalide-catalyzed dehydrative O-alkylation between alcohols: A facile etherification method for aliphatic ether synthesis
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Organohalides are found to be effective catalysts for dehydrative O-alkylation reactions between alcohols, providing selective, practical, green, and easily scalable homo- and cross-etherification methods for the preparation of useful symmetrical and unsymmetrical aliphatic ethers from the readily available alcohols. Mechanistic studies revealed that organohalides are regenerated as reactive intermediates and recycled to catalyze the reactions.
- Xu, Qing,Xie, Huamei,Chen, Pingliang,Yu, Lei,Chen, Jianhui,Hu, Xingen
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supporting information
p. 2774 - 2779
(2015/05/27)
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- Zinc-catalyzed reduction of aldehydes with a hydrosilane leading to symmetric ethers and silyl ethers
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The efficient reductive etherification of aromatic or aliphatic aldehydes using a reducing system that combines Zn(OTf)2 with either TMDS or Et3SiH is described. The present reducing system can also be applied to the hydrosilylation of aromatic aldehydes having either a strong electron-withdrawing group or a pyridine ring.
- Sakai, Norio,Nonomura, Yoshifumi,Ikeda, Reiko,Konakahara, Takeo
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p. 489 - 491
(2013/06/26)
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- Aqueous oxidation of alcohols catalysed by recoverable iron oxide nanoparticles supported on aluminosilicates
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Supported iron oxide nanoparticles on aluminosilicate catalysts were found to be efficient and easily recoverable materials in the aqueous selective oxidation of alcohols to their corresponding carbonyl compounds using hydrogen peroxide under both conventional and microwave heating. The protocol features an easy work-up, simplicity and the utilisation of mild reaction conditions as well as high selectivity toward aldehydes is highly advantageous compared to alternatively reported methodologies. The supported iron oxide nanoparticles could be easily recovered from the reaction mixture and reused several times without any loss in activity. ICP-MS results proved that there is no metal leaching observed, demonstrating the stability of the catalyst under the investigated conditions.
- Rajabi, Fatemeh,Pineda, Antonio,Naserian, Sareh,Balu, Alina Mariana,Luque, Rafael,Romero, Antonio A.
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p. 1232 - 1237
(2013/06/05)
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- Synthesis of ethers from esters via Fe-catalyzed hydrosilylation
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Triiron dodecacarbonyl allows for the selective reduction of esters into the corresponding ethers. This protocol has a wide substrate scope. In addition, cholesteryl pelarogonate has been reduced under the reaction conditions with an excellent yield.
- Das, Shoubhik,Li, Yuehui,Junge, Kathrin,Beller, Matthias
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supporting information
p. 10742 - 10744
(2013/01/15)
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- Intermolecular dehydration of alcohols by the action of copper compounds activated with carbon tetrabromide. synthesis of ethers
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Copper compounds of the general formula CuXn (X = Cl, Br, I, acac, OAc, C7H4O3, C7H 5O2; n = 1, 2) activated by carbon tetrabromide catalyzed intermolecular dehydration of primary and secondary alcohols with formation of the corresponding ethers.
- Khusnutdinov, R. I.,Bayguzina, A. R.,Gimaletdinova, L. I.,Dzhemilev, U. M.
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p. 1191 - 1196,6
(2020/10/15)
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- Triflic acid catalyzed reductive coupling reactions of carbonyl compounds with O-, S-, and N-nucleophiles
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Highly efficient metal-free reductive coupling reactions of aldehydes and ketones with a range of nucleophiles in the presence of triflic acid (1-5 mol %) as the catalyst are presented. The reactions can be performed at ambient temperature without exclusion of moisture or air. A range of symmetrical and unsymmetrical ethers were obtained by this method in high yields and short reaction times. For the first time, the influence of additional functionalization has been studied. Furthermore, the formation of thioethers from ketones (by addition of unmodified thiols) and of sulfonamides from either aldehydes or ketones has been achieved under catalytic conditions.
- Gellert, Beate A.,Kahlcke, Nils,Feurer, Markus,Roth, Stefanie
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supporting information; experimental part
p. 12203 - 12209
(2011/11/07)
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- Liquid-phase dehydration of 1-octanol, 1-hexanol and 1-pentanol to linear symmetrical ethers over ion exchange resins
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Dehydration of 1-octanol, 1-hexanol and 1-pentanol to di-n-octyl ether (DNOE), di-n-hexyl ether (DNHE) and di-n-pentyl ether (DNPE), respectively, has been studied in the liquid phase at 423K in a batch reactor on ion exchange resins as catalysts. Tested catalysts were the macroporous resins Amberlyst 15, Amberlyst 35, CT175, CT275 and CT276 (high crosslinking degree); Amberlyst 16, Amberlyst 36 and CT252 (medium crosslinking degree); Amberlyst 39 and Amberlyst 70 (low crosslinking degree), and the gel type ones CT224, Amberlyst 31, Amberlyst 121 and Dowex 50Wx4-50. Amberlyst 46, an ion-exchange resin sulfonated only at the polymer surface and Nafion NR50 were also tested for comparison purposes. Data show that the yield of linear symmetrical ethers (DNOE, DNHE and DNPE) highly depends on the resin structure so that best results are obtained on Amberlyst 121, Amberlyst 31 and Dowex 50Wx4-50 (the most swollen resins in reaction medium). The high ether yields are due both to the high alcohol conversions and especially to the very high selectivity to ethers (≥94%) shown by that resins. Finally, by comparing initial reaction rates of ether formation with those obtained on Amberlyst 46 an estimation of the fraction of sulfonic groups that take part in the reaction is given.
- Casas,Bringué,Ramírez,Iborra,Tejero
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experimental part
p. 129 - 139
(2012/01/13)
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- Low-temperature rhodium-catalyzed dehydration of primary alcohols promoted by tetralkylammonium and imidazolium halides
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Rhodium complexes, promoted by imidazolium or tetraalkylammonium halide salts, catalyze the dehydration of primary alcohols with good conversion and selectivity.
- Dowson, George R. M.,Shishkov, Igor V.,Wass, Duncan F.
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scheme or table
p. 4001 - 4003
(2011/01/03)
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- Alcohol Dehydration
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Catalyst compositions are disclosed exhibiting activity for dehydrating an alcohol, the composition comprising a source of a Group VIII transition metal, an organic salt, an acid and/or a compound consisting of a conjugate base of an acid bonded to a radical of the alcohol to be dehydrated and, optionally, a ligand. Also disclosed are methods of converting an alcohol into a product using the catalyst composition. The product of the methods may be predominately alkene or ether depending on the method. In some embodiments of the method a second catalyst for converting a product into a further product may be present.
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Page/Page column 6
(2010/11/03)
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- PROCESS FOR MAKING A COMPOSITION COMPRISING AT LEAST TWO DIFFERENT DIALKYL ETHERS
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The present invention relates to a process for making a composition comprising at least two different ethers using ethanol, or a combination of ethanol and methanol, as a starting material.
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Page/Page column 16-17
(2009/06/27)
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- CONTROLLED CATALYSIS
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The present invention provides methods of using a novel sulfonated resin catalyst, showing improved performance. The catalyst has reduced or partial functionalization, throughout the sulfonated region of the polymer, leading to reduced by-product formation and other desirable features. This catalyst has particular usefulness in reactions or processes sensitive to high acidity, e.g., esterification-transesterification.
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Page/Page column 9
(2009/05/28)
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- Chlorine borrowing: An efficient method for an easier use of alcohols as alkylation agents
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Chlorine functionalised tin dioxide nanoparticles proved able to partially convert alcohols into the corresponding chlorides, which act as alkylation agents with an increased electrophilicity, as evidenced on ether formation and Friedel-Crafts reactions.
- Makowski, Philippe,Rothe, Regina,Thomas, Arne,Niederberger, Markus,Goettmann, Frederic
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scheme or table
p. 34 - 37
(2010/04/22)
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- [IrCl2Cp*(NHC)] complexes as highly versatile efficient catalysts for the cross-coupling of alcohols and amines
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A comparative study on the catalytic activity of a series of [IrCl 2Cp*(NHC)] complexes in several C-O and C-N coupling processes implying hydrogen-borrowing mechanisms has been performed. The compound [IrCl2Cp*(InBu)] (Cp* = pentamethyl cyclopentadiene; InBu = 1,3-di-n-butylimidazolylidene) showed to be highly effective in the cross-coupling reactions of amines and alcohols, providing high yields in the production of unsymmetrical ethers and N-alkylated amines. A remarkable feature is that the processes were carried out in the absence of base, phosphine, or any other external additive. A comparative study with other known catalysts, such as Shvo's catalyst, is also reported.
- Prades, Amparo,Corberan, Rosa,Poyatos, Macarena,Peris, Eduardo
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scheme or table
p. 11474 - 11479
(2009/12/03)
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- PROCESS FOR PRODUCING OLEFINS
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A process for converting an olefin having x carbon atoms into an olefin having x+1 carbon atoms wherein the process comprises the steps of: (i) reacting an olefin having x carbon atoms with carbon monoxide and hydrogen in the presence of a hydroformylation catalyst to produce an alcohol having x+1 carbon atoms, and (ii) dehydrating the alcohol produced in step (i) in the presence of a dehydration catalyst to produce an olefin having x+1 carbon atoms characterised in that the the hydroformylation catalyst used in step (i) is based on: (a) a source of cobalt, and (b) a ligand which contains phosphorus and nitrogen.
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Page/Page column 5
(2008/06/13)
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- Catalytic performance of CuO/ZnAl2O4-Al2O3 catalysts in n-hexanol conversion
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A series of CuO/ZnAl2O4-Al2O3 catalysts with various CuO loading were prepared by an impregnation method. The effect of copper oxide addition for the reaction of n-hexanol was examined. The reactions were carried out at atmospheric pressure in a fixed bed reactor in the temperature range of 533-663 K. Experimental data show that the addition of copper oxide into studied catalysts does improve the activity in dehydrogenation of alcohol. Catalysts containing CuO have both dehydration and dehydrogenation properties, whereas ZnAl2O4-Al2O3 carrier only dehydrates alcohol. Obtained results indicate that the dehydrogenation of n-hexanol over CuO/ZnAl2O4-Al2O3 catalysts proceeds via carboxy intermediate.
- Grabowska,Zawadzki,Wrzyszcz
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p. 779 - 787
(2007/10/03)
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- Generation of alkyl hypochlorites in oxidation of alcohols with carbon tetrachloride catalyzed by vanadium and manganese compounds
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Primary alcohols and diols with various structures were subjected to transformations into esters, aldehydes, ketones, and lactones under the action of carbon tetrachloride in the presence of manganese compounds (MnCl 2, MnO2, Mn(OAc)2, Mn(acac)3) and vanadium compounds (VCl5, V2O5, VO(acac) 2) as catalysts. These transformation proceeded with the involvement of alkyl hypochlorites, which were generated in the course of oxidation of alcohols with carbon tetrachloride catalyzed by manganese or vanadium compounds. The optimum molar ratios between the catalyst and reagents were determined, and the reaction conditions for the highly selective synthesis of esters, aldehydes, ketones, and lactones from alcohols were found.
- Khusnutdinov,Shchadneva,Baiguzina,Lavrentieva,Dzhemilev
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p. 2074 - 2079
(2007/10/03)
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- The continuous acid-catalyzed dehydration of alcohols in supercritical fluids: A new approach to the cleaner synthesis of acetals, ketals, and ethers with high selectivity
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We report a new continuous method for forming ethers, acetals and ketals using solid acid catalysts, DELOXAN ASP or AMBERLYST 15, and supercritical fluid solvents. In the case of ether formation, we observe a high selectivity for linear alkyl ethers with little rearrangement to give branched ethers. Such rearrangement is common in conventional syntheses. Our approach is effective for a range of n-alcohols up to n-octanol and also for the secondary alcohol 2-propanol. In the reaction of phenol with an alkylating agent, the continuous reaction can be tuned to give preferential O- or C- alkylation with up to 49% O-alkylation with supercritical propene. We also investigate the synthesis of a range of cyclic ethers and show an improved method for the synthesis of THF from 1,4-butandiol under very mild conditions.
- Gray, William K.,Smail, Fiona R.,Hitzler, Martin G.,Ross, Stephen K.,Poliakoff, Martyn
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p. 10711 - 10718
(2007/10/03)
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- Process for producing ether compound
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Ether compounds, which are useful as solvents, cosmetics, detergents, lubricants, emulsifiers and so on, are produced by reacting (a) a hydroxy compound with a carbonyl compound of (b) a carbonyl compound under hydrogen atmosphere in the presence of a catalyst with ease and at a low cost. The reaction is carried out while removing out produced water by using a dehydrating agent during the reaction; by distilling off the water by azeotropic dehydration and the like; or by blowing gases such as hydrogen gas to flow through the reaction system.
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- Novel reductive Friedel-Crafts alkylation of aromatics catalyzed by indium compounds: Chemoselective utilization of carbonyl moieties as alkylating reagents
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Reductive Friedel-Crafts alkylation of aromatics with ketones or aldehydes was characteristically catalyzed by indium compounds in preference to general catalysts like AlCl3 and BF3, where hydrosilanes would play an important role both as a hydride donor and as a co-catalyst. Chemoselective utilization of ketone moieties as alkylating reagents took place even in the presence of halogen, ester or ether moieties which are very susceptible under traditional Friedel-Crafts conditions. Discussion on a plausible intermediate was carried out by some controlled experiments.
- Miyai, Takashi,Onishi, Yoshiyuki,Baba, Akio
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p. 1017 - 1026
(2007/10/03)
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- Naphthalene derivatives
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Naphthalene derivatives of the fomula I STR1 in which: R1 is an alkyl or alkenyl radical which is unsubstituted, monosubstituted by CH or CF3 or monosubstituted by halogen and has 1 to 15 carbon atoms, it also being possible for one or more CH2 groups in these radicals to be replaced, in each case independently of one another, by --O--, --S--, STR2 --CO--, --CO--O--, --O--CO-- or --O--CO--O-- in such a manner that oxygen atoms are not linked directly to one another, STR3 m is 0, 1 or 2, n is 0 or 1, where m+n is 1 or 2, Z1 and Z2 are each, independently of one another, --CH2 CH2 --, --C C-- or a single bond, L1 and L2 independently of one another, are H or F, x is an alkyl or alkoxy radical which is unsubstituted, monosubstituted by CN or CF3 or substituted bi halogen and has 1 to 15 carbon atoms, or is OH, CN, SCN, OCN, NCS or Q--Y, where Q is a single bond, (CF2)r or O(CF2)r r is 1 or 2, and Y is H, F, Cl or Br, with the provisos that a) in the case where m=0, Z2 =a single bond, n=1 and x=CH CF3 or SCN, L1 is F, b) in the case where m=0, Z2 =a single bond, n=1 and X=alkyl, alkoxy or F a L1 and L2 are identical and are F.
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- Ether synthesis using trifluoromethanesulfonic anhydride or triflates under mild reaction conditions
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Reactions of magnesium alkoxides with trifluoromethanesulfonic anhydride or triflates gave corresponding symmetrical or unsymmetrical ethers in moderate to good yields under mild reaction conditions. The scope and limitations of the reaction are discussed.
- Nishiyama, Tomihiro,Kameyama, Hideaki,Maekawa, Hideki,Watanuki, Kouhei
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p. 258 - 262
(2007/10/03)
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- Indium trichloride catalyzed reductive Friedel-Crafts alkylation of aromatics using carbonyl compounds
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Reductive Friedel-Crafts alkylation of aromatics with aldehydes or ketones using chlorodimethylsilane as a hydride source was effectively promoted by a catalytic amount of indium trichloride, whereas a popular type of Friedel-Crafts catalysts showed less effect.
- Miyai, Takashi,Onishi, Yoshiyuki,Baba, Akio
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p. 6291 - 6294
(2007/10/03)
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- Organic reactions catalyzed by methylrhenium trioxide: Dehydration, amination, and disproportionation of alcohols
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Methylrhenium trioxide (MTO) is the first transition metal complex in trace quantity to catalyze the direct formation of ethers from alcohols. The reactions are independent of the solvents used: benzene, toluene, dichloromethane, chloroform, acetone, and in the alcohols themselves. Aromatic alcohols gave better yields than aliphatic. Reactions between two different alcohols could also be used to prepare unsymmetric ethers, the best yields being obtained when one of the alcohols is aromatic. MTO also catalyzes the dehydration of alcohols to form olefins at room temperature, aromatic alcohols proceeding in better yield. When primary (secondary) amines were used as the limiting reagent, direct amination of alcohols catalyzed by MTO gave good yields of the expected secondary (tertiary) amines at room temperature. Disproportionation of alcohols to alkanes and carbonyl compounds was also observed for aromatic alcohols in the presence of MTO. On the basis of the results of this investigation and a comparison with the interaction between MTO and water, a concerted process and a mechanism involving carbocation intermediates have been suggested.
- Zhu, Zuolin,Espenson, James H.
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p. 324 - 328
(2007/10/03)
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- Influences on the Selectivity of the Kolbe versus the Non-Kolbe Electrolysis in the Anodic Decarboxylation of Carboxylic Acids
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The anodic decarboxylation of 3-oxanonanoic acid (2a) and 3-oxapentadecanoic acid (2b) in methanol leads exclusively to products of the non-Kolbe electrolysis.The influence of coelectrolysis, solvent, current density, degree of neutralization and chain length of the alkoxy group on the anodic decarboxylation of 2a, b have been investigated.An extended alkyl chain in the alkoxy group, coelectrolysis with long-chain fatty acids, ethanol or dimethylformamide as solvent, and a high current density favor the Kolbe coupling against the non-Kolbe electrolysis.Key Words: Kolbe electrolysis/ Non-Kolbe electrolysis/ Carboxylic acids, α-alkoxy-/ Solvent effects
- Klocke, Elisabeth,Matzeit, Agnes,Gockeln, Marianne,Schaefer, Hans J.
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p. 1623 - 1630
(2007/10/02)
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- Photosensitizing agents
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New classes of photosensitizing compounds useful in photodynamic therapy are disclosed. These compounds are simplified dimers and polymers of monohydroxy deuteroporphyrins, hydrophobic ethers of these monomers, and red light-absorbing derivatives of methyl pheophorbide-a.
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- Fluorodestannylation. A Powerful Technique to Liberate Anions of Oxygen, Sulfur, Selenium, and Carbon
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Fluoride ions smoothly destannylate organotin chalcogenides to liberate nucleophilic chalcogenide ions; hence the first nucleophilic oxide (O2-) and selenide (Se2-) transfer agents are reported where the tin atom serves as "group 16 (VIB) transfer agent".In the presence of crown ethers or ammonium salts, this process results in a new way to generate "naked" nucleophiles.Ethers and selenides are formed in good to excellent yield.In addition, a useful C-C bond-forming reaction has been developed by using alkyltins with aldehydes and acid chlorides in the presence of fluroide ion.Aspects concerning reactivity and mechanism are presented.Finally, the generality of the fluorodestannylation procedure and the differences with parallel silicon chemistry are detailed.
- Harpp, David N.,Gingras, Marc
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p. 7737 - 7745
(2007/10/02)
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- Ruthenium-Catalyzed Oxidative Transformation of Alcohols and Aldehydes to Esters and Lactones
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Primary alcohols undergo oxidative condensation upon treatment with RuH2(PPh3)4 catalyst to give esters and molecular hydrogen.Similarly, 1,4- and 1,5-diols can be converted into the corresponding γ- and δ-lactones, respectively.The lactonization is greatly enhanced by accepting hydrogen with an appropriate hydrogen acceptor such as acetone.Primary alcohols are oxidized chemoselectively in the presence of secondary alcohols to give the corresponding lactones.These reactions are operationally simple and highly efficient for synthesis of esters and lactones from alcohols.The principle of the oxidative condensation of alcohols can be extended to ester formation from aldehydes and alcohols.The ruthenium-catalyzed reaction of aldehydes with water gives esters, while the same reaction in the presence of a hydrogen acceptor gives carboxylic acids.The key step of these reactions is the oxidative addition of ruthenium into the OH bonds of alcohols and subsequent β-elimination of (RuH) species to give the corresponding carbonyl compounds.
- Murahashi, Shun-Ichi,Naota, Takeshi,Ito, Keiichiro,Maeda, Yoshihiro,Taki, Hiroshi
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p. 4319 - 4327
(2007/10/02)
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- Method for producing a non greasy protective and emollient film on the skin
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A composition for topical application to the skin contains, as a fatty product to provide a nongreasy protective and emollient film thereon, a polyether oligomer having the formula STR1 wherein R is alkyl having 1-12 carbon atoms; R1, R2, R3 and R4 represent hydrogen or alkyl having 1-6 carbon atoms, with at least two of R1, R2, R3 and R4 being hydrogen; m is 1-4; n has an average value equal to or greater than 2; and the number of carbon atoms in each repetitive unit being at least 4.
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- Chemical Conversions using Sheet Silicates: Novel Intermolecular Dehydrations of Alcohols to Ethers and Polymers
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Aliphatic primary alcohols, when intercalated in certain ion-exchanged montmorillonites, react preferentially via an intermolecular nucleophilic displacement of water to give high yields of di-(alk-1-yl) ethers, rather than the competitive intramolecular dehydration to alkenes; an essentially similar process yields polymeric material, poly(phenylenemethylene), from benzyl alcohol, but aliphatic secondary and tertiary alcohols, in contrast, yield alkenes almost exclusively.
- Ballantine, James A.,Davies, Mary,Purnell, Howard,Rayanakorn, Mongkon,Thomas, John M.,Williams, Kevin J.
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p. 427 - 428
(2007/10/02)
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