- Catalytic reactions using superacids in new types of ionic liquids
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We will describe the use of superacids, in particular 1,1,2,2- tetrafluoroethanesulfonic acid (TFESA) and 1,1,2,3,3,3-hexafluoropropanesulfonic acid (HFPSA) in the presence of ionic liquids for improved chemical processing for a range of industrially important chemical reactions. In a number of cases the reaction mixture starts as a single phase, allowing for high reactivity, then separates into two phases upon completion of the reaction. This allows for ease of product separation P. T. Anastas and T. C. Williamson, Green Chemistry: Frontiers in Benign Chemical Syntheses and Processes, Oxford University Press, 1998.1
- Harmer, Mark A.,Junk, Christopher P.,Rostovtsev, Vsevolod V.,Marshall, William J.,Grieco, Liane M.,Vickery, Jemma,Miller, Robert,Work, Stella
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Read Online
- 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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- Solvent- and Metal-free Oxidative Esterification of Aromatic Aldehydes Using Urea-2,2-dihydroperoxypropane as a New Solid Oxidant
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Urea-2,2-dihydroperoxypropane as a noble and solid gem-dihydroperoxide derivative was used to transform various aromatic aldehydes to their corresponding benzoate derivatives in the presence of HBr under mild conditions at room temperature in high yields and short reaction times.
- Khosravi, Kaveh,Khalaji, Kobra,Naserifar, Shirin
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p. 303 - 309
(2017/03/27)
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- Cellulose oxidation and the use of carboxyl cellulose metal complexes in heterogeneous catalytic systems to promote suzuki-miyaura coupling and C?O bond formation reaction
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This work shows the modification of microcrystalline cellulose by the selective oxidation of primary hydroxyl groups to carboxylate groups by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated system and its application as a heterogeneous ligand by ionic exchange with catalytic metals ions such as palladium, nickel and copper. Afterwards is described the application of the synthesized material as catalyst in coupling reactions such as Suzuki-Miyaura coupling and C?O bond formation reaction in different conditions, which are of great importance for the synthesis of drugs, natural products and new materials such as dendrimers, liquid crystals and polymers with magnetic and optical properties. The carboxyl cellulose matrix shows to have superior catalytic results as a ligand for all coupling reactions. Can be also highlighted the affinity of the carboxyl cellulose ligand in polar solvents such as water and alcohols and its application in mild conditions.
- Martins, Guilherme B. C.,Dos Santos, Marcelo R.,Rodrigues, Marcus V. R.,Sucupira, Renata R.,Meneghetti, Luisa,Monteiro, Adriano L.,Suarez, Paulo A. Z.
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p. 2064 - 2072
(2017/09/23)
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- PROCESS FOR THE PRODUCTION OF DIPENTYL ETHER FROM LEVULINIC ACID RESULTING FROM BIOMASS
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A process for the production of dipentyl ether from levulinic acid resulting from biomass including at least one polysaccharide comprising the following steps: (a) reacting said levulinic acid in the presence of hydrogen and at least one non-acid hydrogenation catalyst obtaining γ-valerolactone; (b) reacting said γ-valerolactone in the presence of hydrogen and at least one acid hydrogenation catalyst obtaining pentanoic acid; (c) reacting said pentanoic acid in the presence of hydrogen and at least a catalyst comprising platinum (Pt) and tin (Sn) obtaining pentyl alcohol; (d) reacting said pentyl alcohol in the presence of at least one solid acid catalyst thereby obtaining dipentyl ether. The dipentyl ether thus obtained can be advantageously used as an oxygenated component for fuels for diesel engines.
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Page/Page column 17
(2016/09/22)
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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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- Magnetic Polystyrene Nanosphere Immobilized TEMPO: A Readily Prepared, Highly Reactive and Recyclable Polymer Catalyst in the Selective Oxidation of Alcohols
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The 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical immobilized on the magnetic polystyrene nanospheres (MPNs) was used as a recyclable catalyst in the oxidation of various alcohols. The new and simply prepared heterogeneous TEMPO/MPNs exhibits both similar versatility and efficiency to homogeneous TEMPO under basic Montanari conditions. The excellent stability of the MPNs enables the TEMPO/MPNs to be recycled more than 20times without significant leaching of immobilized TEMPO radicals or degradation of Fe3O4 nanoparticles. Moreover, the magnetic response ensures the rapid separation and quantitative recycling of TEMPO/MPNs by simple magnetic decantation.
- Zheng, Zhi,Wang, Jianli,Zhang, Miao,Xu, Lixin,Ji, Jianbing
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p. 307 - 312
(2013/03/13)
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- Copper(II) triflate-catalyzed reduction of carboxylic acids to alcohols and reductive etherification of carbonyl compounds
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A protocol is described for the reduction of carboxylic acids to primary alcohols using 1,1,3,3-tetramethyldisiloxane (TMDS) and a catalytic amount of Cu(OTf)2. Aliphatic as well as aromatic carboxylic acids are reduced in high selectivity and good yields. TMDS/Cu(OTf)2 has also been found to be an efficient catalytic reducing system for the preparation of symmetrical ethers from carbonyl compounds under mild conditions.
- Zhang, Yin-Jie,Dayoub, Wissam,Chen, Guo-Rong,Lemaire, Marc
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experimental part
p. 7400 - 7407
(2012/09/10)
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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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- 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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- 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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- 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 5
(2010/11/03)
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- Oxidation of monohydric and dihydric alcohols with CCl4 catalyzed by molybdenum compounds
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Mo(CO)6 catalyzed oxidation of alcohols and diols with tetrachloromethane. Primary oxidation products in reaction of alcohols with CCl4 are alkyl hypochlorites, and final products depending on the structure of initial alcohol are aldehydes (as acetals), ketones, chloroketones, and esters.
- Khusnutdinov,Shchadneva,Burangulova,Muslimov,Dzhemilev
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p. 1615 - 1621
(2007/10/03)
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- Reaction of orthoesters with alcohols in the presence of acidic catalysts: A study
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Allylic and benzylic alcohols are converted into corresponding unsymmetrical ethers when reacted with various orthoesters in the presence of montmorillonite KSF at ambient temperature. A detailed study has been undertaken to examine the mechanism and generality of these reactions with regard to various acidic catalysts, which reveal interesting competitive reactions mainly O-acetylation, together with trace amount of dimerized product. The type of the side product and their relative quantity depends upon the nature of the catalyst employed. Furthermore, the low yields of the Claisen rearrangement product obtained from allylic alcohols under heating is rationalized due to the formation of some of these products.
- Sampath Kumar,Joyasawal, Sipak,Reddy,Pawan Chakravarthy,Krishna,Yadav
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p. 1686 - 1692
(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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- Preparation of carbocyclic compounds
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The present invention provides new synthetic methods and compositions. In particular, new methods of preparing intermediates useful in the synthesis of neuraminidase inhibitors and compositions useful as intermediates that are themselves useful in the synthesis of neuraminidase inhibitors are provided.
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- PREPARATION OF CARBOCYCLIC COMPOUNDS
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The present invention provides new synthetic methods and compositions. In particular, new methods of preparing intermediates useful in the synthesis of neuraminidase inhibitors and compositions useful as intermediates that are themselves useful in the synthesis of neuraminidase inhibitors are provided.
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- Use of pseudopterosins for promoting wound healing
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Methods of promoting wound healing and the growth and proliferation of keratinocytes, fibroblasts and endothelial cells are disclosed. These methods comprise contacting a wound with an effective wound healing amount of a composition comprising a pseudopterosin or pseudopterosin derivative.
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- Ether derivatives of pseudopterosin
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Methods for treating mammals to reduce pain and/or reduce inflammation are described based on administering to the mammals synthetic ether derivatives of pseudopterosin having the formula: STR1 wherein A is an alkyl, aryl or amide group having from 2 to 20 carbon atoms, R1, R2 and R3 are hydrogen or an acyl residue (--COR) having from 1 to 6 carbon atoms, R4 is hydrogen or --CH2 OH and R5 is a hydrocarbon having from 1 to 10 carbon atoms. Also disclosed are synthetic compositions having the above general formula which are useful in the described method.
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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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- Phosphinyloxy propanaminium inner salt derivatives
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Compounds of the formula STR1 where X1 and X2 are independently O or S, and R1 is as defined in the description R2, R3, and R4 are each independently straight or branched chain (C1-4)alkyl, and pharmaceutically acceptable salts, physiological hydrolysable esters, and pro-drug forms thereof are useful as hypoglycemic agents.
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- Process for preparing phosphinyloxy propanaminium inner salt derivatives
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A process for preparing compounds of the formula STR1 where X1 and X2 are independently O or S, and R1 is as defined herein, R2, R3, and R4 are each independently straight or branched chain (C1-4)alkyl, and pharmaceutically acceptable salts, physiological hydrolyzable esters, and pro-drug forms thereof, which are useful as hypoglycemic agents.
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- KINETICS OF CATALYTIC DEHYDRATION OF 1-PENTANOL
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Kinetic data of 1-pentanol dehydration of γ-alumina catalyst modified by potassium hydroxide were obtained using a continuous reactor with an internal recirculation.The conversion of 1-pentanol on this catalyst in the temperature range 300-390 deg C and space velocity 1-8 kg (h kg)-1 (molar fraction of water in the feed was in the range 0-0.56) was 50-98percent and the selectivity with respect to 1-pentene was 50-84percent.The following six reactions have been taken into account to describe the catalytic dehydration of 1-pentanol: direct formation of 1-pentene from 1-pentanol, formation of bis(1-pentyl) ether from 1-pentanol, disproportionation of the ether to 1-pentanol and 1-pentene, formation 1-pentene from the ether, isomerization of 1-pentene to 2-pentene and hydrolysis of the ether to 1-pentanol.Treatment of experimental data by Langmuir-Hinshelwood model showed that the model involving adsorption of 1-pentanol accompanied by dissociation in the most suitable one.
- Vasutova, Iveta,Kralik, Milan,Hronec, Milan
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p. 1874 - 1885
(2007/10/02)
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- Continuous Conversion of Alcohols into Alkyl Halides by Gas-Liquid Phase-Transfer Catalysis (G.L.-P.T.C)
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A solution of a primary alcohol (propan-1-ol, butan-1-ol, and pentan-1-ol) in an aqueous halogen acid (hydrochloric or hydrobromic acid) when passed in the gaseous state over a solid porous bed (silica gel) supporting a catalyst, affords the corresponding alkyl halide.The reagent mixture is introduced continuously into a column maintained at 170 deg C and the product is collected at the outlet.Since the process is catalytic, the bed is not consumed during the reaction.The reaction by-products depend on the type of catalyst used: Lewis acids (ZnCl2, AlCl3) lead to large quantities of alkenes and isomeric halides, while under typical g.l.- p.t.c. conditions, with a phosphonium salt as the catalyst, only the corresponding dialkyl ether, in addition to the primary alkyl halide, is obtained.The yield of the ether can be reduced progessively to zero by increasing the contact time between the reaction mixture and the catalytic bed.
- Tundo, Pietro,Venturello, Paolo,Angeletti, Enrico
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p. 2157 - 2158
(2007/10/02)
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- Reduction of carbonyl compounds promoted by silicon hydrides under the influence of trimethylsilyl-based reagents
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The synthetic utility of hydrosilanes under the influence of trimethylsilyl-based reagents as new reducing systems is described. 1,1,3,3-Tetramethyldisiloxane (TMDS) reagent in combination with iodotrimethylsilane or bromotrimethylsilane produces alkyl halides from aldehydes in good to excellent yields.Polymethylhydrosiloxane (PMS) in the presence of iodotrimethylsilane also produces benzyl iodides in excellent yields.On the contrary, PMS reagent was found unsuitable for the synthesis of benzyl bromides.Similary, TMDS reagent in combination with trimethylsilyl triflate produces symmetrical ethers from aldehydes without concomitant formation of competitive products.Under similar conditions, PMS reagent failed to provide the expected symmetrical ethers and Friedel-Crafts products were formed.Reduction of quinones to hydroquinones is also described.
- Aizpurua, Jesus M.,Lecea, Begona,Palomo, Claudio
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p. 2342 - 2347
(2007/10/02)
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- Synthesis, Characterization, and Catalytic Activity of Beidellite-Montmorillonite Layered Silicates and their Pillared Analogues
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A synthetic beidellite-smectite, characterized by a range of techniques, including high-resolution 27Al and 29Si solid-state n.m.r. spectroscopy, shows interesting catalytic activity (in secondary amine formation from cyclohexylamine, in ester production from hex-1-ene and acetic acid, and in ether synthesis from pentanol): the selectivities differ significantly from those of montmorillonite-smectites.
- Diddams, Paul A.,Thomas, John M.,Jones, William,Ballantine, James A.,Purnell, J. Howard
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p. 1340 - 1342
(2007/10/02)
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- SYNTHESIS OF BENZYL HALIDES FROM ALDEHYDES PROMOTED BY HALOSILANES AND 1,1,3,3-TETRAMETHYLDISILOXANE (TMDS).
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Direct synthesis of monoalkyl halides from aldehydes by a new reductive halogenation method is briefly described.
- Aizpurua, Jesus M.,Palomo, Claudio
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p. 1103 - 1104
(2007/10/02)
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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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