- 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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- Phosgene-free synthesis of symmetric bis(polyfluoroalkyl) carbonates
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A phosgene-free synthesis of symmetric bis(polyfluoroalkyl) carbonates involves the transesterification of diphenyl carbonate with polyfluoroalkanols promoted by stoichiometric amounts of titanium(iv) alkoxides.
- Semenova, Anna M.,Ezhikova, Marina A.,Kodess, Mikhail I.,Zapevalov, Aleksandr Ya.,Pestov, Aleksandr V.
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p. 257 - 258
(2021/05/04)
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- METHOD FOR PRODUCING CARBONIC ESTER
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To achieve a method for producing a carbonic ester at a high yield by a simple process while suppressing formation of by-products, for example, a method for producing an aliphatic carbonic ester. The above problem is solved by a method for producing a carbonic ester, the method including a carbonic ester formation reaction in which an alcohol and carbon dioxide are reacted in the presence of an aromatic nitrile compound and a catalyst, wherein the water content in the alcohol used in the carbonic ester formation reaction is 0.10% by mass or less.
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Paragraph 0101-0118
(2021/03/05)
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- METHOD FOR PRODUCING CARBONATE ESTERS, AND CATALYTIC STRUCTURE FOR PRODUCING CARBONATE ESTERS
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Provided are a method for producing carbonate esters, and a catalytic structure for producing carbonate esters, whereby solid catalyst powder formation and detachment are suppressed and superior carbonate ester reaction efficiency is yielded when a catalytic structure constituted by a sufficient quantity of a cerium-oxide-containing solid catalyst supported on a substrate is used. The method for producing carbonate esters includes reacting a monohydric alcohol and carbon dioxide in the presence of a catalytic structure and a hydrating agent. The catalytic structure includes a substrate and a catalytic layer that is formed on at least a portion of the surface of the substrate and contains a solid catalyst and an inorganic binder. The solid catalyst contains cerium oxide. The supported quantity of the solid catalyst is 15 g/m2 to 200 g/m2, inclusive. The inorganic binder contains silica and/or alumina.
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Paragraph 0148-0149; 0179-0180
(2021/09/17)
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- Transfer hydrogenation of cyclic carbonates and polycarbonate to methanol and diols by iron pincer catalysts
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Herein, we report the first example on the use of an earth-abundant metal complex as the catalyst for the transfer hydrogenation of cyclic carbonates to methanol and diols. The advantage of this method is the use of isopropanol as the hydrogen source, thus avoiding the handling of flammable hydrogen under high pressure. The reaction offers an indirect route for the reduction of CO2 to methanol. In addition, poly(propylene carbonate) was converted to methanol and propylene glycol. This methodology can be considered as an attractive opportunity for the chemical recycling of polycarbonates.
- Liu, Xin,De Vries, Johannes G.,Werner, Thomas
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p. 5248 - 5255
(2019/10/11)
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- Method of manufacturing Dialkyl carbonate using carbon dioxide
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In the embodiment of the present invention consists of a carbon dioxide using the d alkyl car this [thu [thu] which it sees a manufacturing method is provided other [...] number one, alcohol, imidazolium cation and bicarbonate mixing negative catalyst and bases the solvent to form a mixture, said mixture by mixing said reactants including injecting carbon dioxide for generating an agitating the manufacturing method characterized in that the d alkyl car this [thu [thu] which it sees a number [...] substrate. (by machine translation)
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Paragraph 0073-0079; 0088; 0149-0151
(2019/08/12)
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- The design of efficient carbonate interchange reactions with catechol carbonate
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Catechol carbonate (CC) has been investigated as an innovative and highly active reactant for carbonate interchange reactions (CIRs). Under mild conditions (atmospheric pressure, and 60-80°C), the selective synthesis of symmetric aliphatic carbonates (ROCO2R) has been achieved by the reaction of a slight excess of both primary and secondary alcohols with CC in the presence of NaOMe or MgO as a catalyst. Quantitative conversions have been reached in only 1 hour and products have been isolated in yields of up to 58% for dibutylcarbonate. Of note is that the reaction of glycerol with CC also proceeded under similar conditions (40-60°C, 1 atm) to afford glycerol carbonate (96-98%). The comparison of the reactivity of CC with that of conventional dialkyl carbonates, including dimethyl carbonate (DMC) and ethylene carbonate (EC), proved the superior performance of CC in all the investigated CIR processes. Accordingly, a mechanism has been formulated based on the leaving group ability of a catecholate anion originating from CC.
- Tabanelli,Monti,Cavani,Selva
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p. 1519 - 1528
(2017/05/01)
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- PROCESS FOR THE PREPARATION OF ORGANIC CARBONATE DERIVATES
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The present invention relates in general terms to a new process for the preparation of organic carbonate derivatives, cyclic or linear by a trans carbonation reaction between PCC and a suitable aliphatic alcohol, in the presence of a homogeneous or heterogeneous basic catalyst; the process allows to optimize yields and selectivities of the obtained products, especially in the case of the preparation of symmetrical linear or cyclic carbonates starting from the corresponding primary alcohols.
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Page/Page column 24; 25
(2017/04/11)
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- Production of carbonate
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PROBLEM TO BE SOLVED: To provide a method for producing a carbonic acid ester, which enables a high reaction speed and a high reaction rate by reacting a monohydric alcohol with carbon dioxide in the presence of a solid catalyst, even under a mild reaction condition of relatively low pressure. SOLUTION: A monohydric alcohol is reacted with carbon dioxide in the presence of a solid catalyst and a nitrile compound to form a carbonic acid ester and water, an amide compound is formed by a hydration reaction between the nitrile compound and the formed water, and the formed water is removed from the reaction system or reduced to promote the formation of the carbonic acid ester. COPYRIGHT: (C)2012,JPOandINPIT
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Paragraph 0064; 0116-0118
(2016/12/22)
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- Palladium catalyzed oxidative carbonylation of alcohols: Effects of diphosphine ligands
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The catalytic activity of a series of palladium diphosphine complexes of the type [PdX2(P∩P)] has been studied in the oxidative carbonylation of i-PrOH with p-benzoquinone as an oxidant. Diphosphine ligands have been chosen in order to cover a wide range of bite angles and electronic and steric parameters. Their properties have been correlated with the catalytic activity and selectivity of the reaction. The best catalytic performance has been achieved with weakly coordinating anions as well as non-bulky and electron-donating P∩P ligands with a relatively wide bite angle yet capable of maintaining a cis-coordination, such as cis-[Pd(OTs)2(pMeO-dppf)]. These results and those on the reactivity of dicarboalkoxy species of the type cis-[Pd(COOMe)2(P∩P)] toward reductive elimination, which is a crucial step in oxalate formation, suggest that the slow step of the catalysis depends on the nature of the P∩P ligand.
- Amadio, Emanuele,Freixa, Zoraida,Van Leeuwen, Piet W. N. M.,Toniolo, Luigi
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p. 2856 - 2864
(2015/07/14)
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- Production of carbonate
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PROBLEM TO BE SOLVED: To provide a production method which can also obtain a carbonic ester at even a mild reaction condition, controls the discharge of a by-product, and can easily separate/purify the carbonic ester.SOLUTION: The method of producing a carbonic ester includes a step in which a compound of formula (1) is made to react with carbon dioxide under the presence of a polar organic solvent. In the formula, R-Reach independently are a monovalent hydrocarbon group; and Rand Rmay mutually combine directly or through other groups.
- -
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Paragraph 0051-0054
(2017/01/02)
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- Efficient oxidative carbonylation of iPrOH to oxalate catalyzed by Pd(II)-PPh3 complexes using benzoquinone as a stoichiometric oxidant
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The catalytic system trans-[PdBr2(PPh3) 2]/NEt3/PPh3/LiBr is highly active and selective in the oxidative carbonylation of iPrOH to the corresponding oxalate using benzoquinone (BQ) as a stoichiometric oxidant. The oxalate is formed together with minor amounts of carbonate and acetone. The influence of each component in the catalytic system is discussed together with the influence of the concentration of BQ, reaction time, temperature and CO pressure. NEt3 neutralizes the acid released in the catalytic cycle, thus favouring the formation of a dicarboalkoxy intermediate. Added PPh 3 reacts with benzoquinone giving betaine, which is a base that contributes to a further enhancement of the catalytic activity. The Br - anion might coordinate the Pd(0) which is formed in the product forming step thus stabilizing it against decomposition and making its reoxidation easier and reentering into the catalytic cycle. The catalytic activity depends slightly only on the concentration of BQ, suggesting that either uncoordinated BQ is not involved in the slow step of the catalytic cycle or that BQ is strongly coordinated in these species. The catalytic activity toward oxalate increases upon increasing the concentrations of NEt3 and PPh3, whereas the selectivity toward carbonate and the formation of acetone remains practically constant. The increase of the pressure of CO has a similar effect, except that the formation of acetone is suppressed. It is suggested that at relatively high pressure of CO, a pentacoordinated species may be formed so that there is no place for any interaction between palladium and the C-H bond before the β-H elimination. Instead there is a nucleophilic intrasphere attack of the alkoxy ligand onto a CO ligand. After catalysis the precursor trans-[PdBr2(PPh3)2] has been detected, together with trans-[PdBr(COOiPr)(PPh3) 2] and [Pd(BQ)(PPh3)2]. PPh3 remains coordinated to the palladium centre during catalysis. A BQ- and halides-assisted catalytic cycle is proposed. In this cycle, the reoxidation occurs through the release of a proton from an ammonium salt or a phosphonium salt, which are formed during the catalysis, with reformation of the catalyst precursor.
- Amadio,Toniolo
-
-
- Development of complex approach to the synthesis of trimethylene carbonate as a monomer for biodegradable polymers
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With the aim of production of polymers for medicine a new preparation method was developed for trimethylene carbonate based on transesterification with trimethylene glycol of dialkyl carbonates obtained without the use of phosgene. As initial reagents alkylene carbonates or polycarbonates and titanium alkoxides can be utilized. The advantages of this approach consist in obtaining some additional useful substances and the possibility of reprocessing polycarbonate wastes.
- Kuznetsov,Pervova,Pestov
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p. 654 - 658
(2014/07/08)
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- Organic carbonate synthesis from CO2 and alcohol over CeO 2 with 2-cyanopyridine: Scope and mechanistic studies
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The combination system of CeO2-catalyzed carboxylation and 2-cyanopyridine hydration (CeO2 + 2-cyanopyridine system) is effective for the direct synthesis of organic carbonates from CO2 and alcohols. This catalyst system can be applied to various alcohols to afford the corresponding carbonates in high alcohol-based yields. The hydration of 2-cyanopyridine over CeO2 rapidly proceeds under the low concentration of water, which can remove the water from the reaction media. Since the reaction is limited by the chemical equilibrium, the removal of water remarkably shifts the chemical equilibrium to the carbonate side, leading to high carbonate yields. In addition, 2-picolinamide that is produced by hydration of 2-cyanopyridine forms an intramolecular hydrogen bonding between H atom of the amide group and N atom of the pyridine ring, which weakens the adsorption of 2-picolinamide on CeO2 by reduction of the acidity. The reaction mechanism of DMC formation in CeO2 + 2-cyanopyridine system is also proposed.
- Honda, Masayoshi,Tamura, Masazumi,Nakagawa, Yoshinao,Nakao, Kenji,Suzuki, Kimihito,Tomishige, Keiichi
-
-
- Heterogeneous CeO2 catalyst for the one-pot synthesis of organic carbamates from amines, CO2 and alcohols
-
Heterogeneous CeO2 catalyst can catalyze the one-pot synthesis of methyl benzylcarbamate from benzylamine, CO2 and methanol. The yield of methyl benzylcarbamate reached 92% at >99% benzylamine conversion and 92% benzylamine-based selectivity even in the absence of the dehydrating agents. The catalyst is reusable after the calcination at 873 K for 3 h. Various carbamates can be synthesized with good yield and high selectivity by the reaction of amines + CO2 + alcohols over CeO2. The main formation route of methyl benzylcarbamate is suggested to be the reaction of dimethyl carbonate or the precursor of dimethyl carbonate formation with benzylamine.
- Honda, Masayoshi,Sonehara, Satoru,Yasuda, Hiroshi,Nakagawa, Yoshinao,Tomishige, Keiichi
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scheme or table
p. 3406 - 3413
(2012/01/15)
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- NaZSM-5-catalyzed dimethyl carbonate synthesis via the transesterification of ethylene carbonate with methanol
-
NaZSM-5 zeolite was found to be an efficient heterogeneous catalyst for the synthesis of dimethyl carbonate (DMC), which can serve as a building block, an additive to fuel oil, and an electrolyte in batteries, via the transesterification of ethylene carbonate (EC) with methanol. Notably, 77% DMC yield and 97% selectivity were achieved under mild reaction conditions. Furthermore, the effects of various reaction parameters such as catalyst loading, reaction time, and methanol/EC molar ratio on the catalytic performance were investigated in detail. This protocol was found to be applicable to a variety of alcohols, producing the corresponding dialkyl carbonates with moderate yields and selectivities. Moreover, the catalyst can be recovered by simple filtration with retention of catalytic activity; a stable crystal configuration and a slight alteration of its superficial structure were observed by X-ray diffraction and BET measurements.
- Yang, Zhen-Zhen,Dou, Xiao-Yong,Wu, Fang,He, Liang-Nian
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experimental part
p. 544 - 548
(2011/10/03)
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- Synthesis of carbamates from amines and dialkyl carbonates: Influence of leaving and entering groups
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A number of carbamates were synthesised through a halogen-free process by reacting amines with symmetrical and unsymmetrical carbonates. The results obtained showed a specific trend of preferred leaving groups (in the dialkyl carbonates) depending on whether a catalyst or a base was used. On the other hand, investigations conducted on the preferred entering groups (amines) for the synthesis of carbamates showed the same trend regardless of whether a catalyst or a base was used. Finally, in accordance with the results obtained, it was possible to synthesise sterically hindered carbamates in high yield by transesterification of methyl carbamate with a sterically hindered alcohol. Georg Thieme Verlag Stuttgart New York.
- Tundo, Pietro,McElroy, C. Robert,Aricò, Fabio
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supporting information; experimental part
p. 1567 - 1571
(2010/09/05)
-
- A convenient titanium-mediated intermolecular alkyne-carbonate coupling reaction
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A direct diastereoselective titanium-mediated intermolecular coupling of internal alkynes with dialkyl carbonates under Kulinkovich-type reaction conditions is presented. The influence of the structures of the coupling partners on the yields and regioselectivities of this transformation is described.
- Wolan, Andrzej,Cadoret, Frédéric,Six, Yvan
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supporting information; experimental part
p. 7429 - 7439
(2009/12/06)
-
- Phenylimidazolidines containing nitrooxy or carbonyloxy groups
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A subject of the invention is the products of formula (I): in which: R1and R2represent in particular cyano and trifluoromethyl, R3represents in particular alkyl, alkenyl or alkynyl, substituted in particular by nitrooxy or carbonyloxy, R4and R5represent in particular methyl optionally substituted by fluorine, X and Y represent in particular oxygen, as well as their salts and isomers.
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-
-
- Di-tert-butyl dicarbonate and 4-(dimethylamino)pyridine revisited. Their reactions with amines and alcohols
-
The reaction of BOC2O in the presence and absence of DMAP was examined with some amines, alcohols, diols, amino alcohols, and aminothiols. Often, unusual products were observed depending on the ratio of reagents, reaction time, polarity of solvent, pK(a) of alcohols, or type of amine (primary or secondary). In reactions of aliphatic alcohols with BOC2O/DMAP, we isolated for the first time carbonic-carbonic anhydride intermediates; this helps explain the formation of symmetrical carbonates in addition to the O-BOC products. In the case of secondary amines, we succeeded to isolate unstable carbamic-carbonic anhydride intermediates that in the presence of DMAP led to the final N-BOC product. The effect of N-methylimidazole in place of DMAP was also examined.
- Basel, Yochai,Hassner, Alfred
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p. 6368 - 6380
(2007/10/03)
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- Direct condensation reaction of carbon dioxide with alcohols using trisubstituted phosphine-carbon tetrabromide-base system as a condensing agent
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This paper describes the preparation of carbonates by the direct condensation of CO2 with alcohols using a trisubstituted phosphine-carbon tetrabromide-base system as a condensing agent. The yield of dibenzyl carbonate from CO2 and benzyl alcohol was at most 90.7%. The reaction of CO2 with the other primary alcohols such as methanol, ethanol, butan-1-ol, hexan-1-ol, allyl alcohol, and ethylene glycol also gave corresponding carbonates in relatively high yields, whereas yields of carbonates from CO2 and secondary alcohols were low. Copyright 1999 by the Royal Society of Chemistry.
- Kadokawa, Jun-Ichi,Habu, Hideyuki
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p. 2205 - 2208
(2007/10/03)
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- Alkoxycarbonylation of alcohols and phenols by nitrosoformates
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Unstable neutral radicals [ROCONHO?] 2 and nitrosoformates 3 are formed by oxidation of N-hydroxycarbamates with lead dioxide. In the presence of alcohols or phenols and water they solvolyzed to mixtures of symmetrical 4 and asymmetrical 5 carbonates. The content of asymmetrical carbonates 5 increases with increasing reactivity of the nitrosoformates 3 formed, temperature, the content of water in the reaction mixture, and with decreasing reactivity of alcohol. The reactivities of individual alcohols have been evaluated with the help of competitive alcoholysis. The new method of alcohol or phenol alkoxylation has been verified experimentally by preparing six asymmetrical carbonates which were obtained in 34 to 47% yields.
- Mindl, Jaromir,Halama, Ales,Cernosek, Zdenek
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p. 1053 - 1063
(2007/10/03)
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- Synthesis of O-Alkyl Carbonochloridothioates
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The preparation of O-alkyl carbonochloridothioates (2) was improved by performing the reaction of thiophosgene with potassium alkoxides in the corresponding alcohol or in tetrahydrofuran at -65 deg C for 1 hour.In all cases, the reaction yielded products 2, O,O-dialkyl carbonothioates (4), and dialkyl carbonates (5) in varying distribution.
- Martinez, Manuel A.,Vega, Juan C.
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p. 760 - 761
(2007/10/02)
-
- Nucleophilic Substitutions at Carbonic Acid Derivatives. XIX. Alcoholysis and Hydrolysis of Bis(trichloromethyl)carbonate
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The rate constants of hydrolysis and alcoholysis of bis(trichlormethyl)carbonate in dioxane have been determinated conductometrically.The effects of the water and alcohol concentrations, the temperature and deuterium have been studied.By the hydrolysis and alcoholysis of bis(trichlormethyl)carbonate the nucleophilic attack of water and alcohol is the rate-determining step, followed by a fast elimination of unstable trichloromethanol.
- Cotarca, Livius,Bacaloglu, Radu,Marcu, Nicolae,Tarnaveanu, Alexandru
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p. 881 - 886
(2007/10/02)
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- A FACILE PREPARATION OF DIALKYL CARBONATES FROM POTASSIUM CARBONATE AND ALKYL BROMIDES BY USING ORGANOSTANNYL COMPOUND AS A CATALYST
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Dialkyl carbonates were easily prepared by the heterogeneous reaction of solid potassium carbonate with alkyl bromides in dimethylformamide or dimethylsulfoxide in the presence of organostannyl compound such as hexabutyldistannoxane or chlorotributylstannane.Mixed catalytic system consisting of a tributylstannyl compound and 18-Crown-6 was much effective even in less polar solvents.
- Fujinami, Tatsuo,Sato, Shinichi,Sakai, Shizuyoshi
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p. 749 - 752
(2007/10/02)
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- Peroxide-initiated Reaction of Secondary Alcohols with Carbon Tetrachloride on a Zinc Oxide Surface
-
A free radical initiated chain reaction has been found to take place in mixtures of secondary alcohols with carbon tetrachloride on a zinc oxide surface, resulting in the formation of the corresponding ketones with concomitant formation of chloroform and hydrogen chloride.The peroxide impurities that are present in the secondary alcohols are found to undergo homolysis on the surface of zinc oxide to form reactive free radicals which initiate a free radical chain reaction in the secondary alcohols and carbon tetrachloride.
- Sudhakar, Ch.,Rao, V. R. S.,Kuriacose, J. C.
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p. 693 - 695
(2007/10/02)
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