- Control of Product Selectivity for the Epoxidation of Allyl Alcohol by Variation of the Acidity of the Catalyst TS-1
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The acidity of TS-1 controls the product selectivity for the epoxidation of allyl alcohol with H2O2; base treatment of TS-1 enhances the selectivity to glycidol whereas incorporation of Broensted acid sites enhances the selectivity to the products of solvolysis ring opening reactions.
- Hutchings, Graham J.,Lee, Darren F.
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- Regioselective Ring-Opening of Glycidol to Monoalkyl Glyceryl Ethers Promoted by an [OSSO]-FeIII Triflate Complex
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A FeIII-triflate complex, bearing a bis-thioether-di-phenolate [OSSO]-type ligand, was discovered to promote the ring-opening of glycidol with alcohols under mild reaction conditions (0.05 mol % catalyst and 80 °C). The reaction proceeded with high activity (initial turnover frequency of 1680 h?1 for EtOH) and selectivity (>95 %) toward the formation of twelve monoalkyl glyceryl ethers (MAGEs) in a regioselective fashion (84–96 % yield of the non-symmetric regioisomer). This synthetic approach allows the conversion of a glycerol-derived platform molecule (i.e., glycidol) to high-value-added products by using an Earth-crust abundant metal-based catalyst.
- Monica, Francesco Della,Ricciardi, Maria,Proto, Antonio,Cucciniello, Raffaele,Capacchione, Carmine
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p. 3448 - 3452
(2019/08/01)
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- Optimization of the synthesis of glycerol derived monoethers from glycidol by means of heterogeneous acid catalysis
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We present an efficient and green methodology for the synthesis of glycerol monoethers, starting from glycidol and different alcohols, by means of heterogeneous acid catalysis. A scope of Br?nsted and Lewis acid catalysts were applied to the benchmark reaction of glycidol and methanol. The selected catalysts were cationic exchangers, such as Nafion NR50, Dowex 50WX2, Amberlyst 15 and K10-Montmorillonite, both in their protonic form and exchanged with Al(III), Zn(II) and Fe(III). Thus, total conversions were reached in short times by using 1 and 5% mol catalyst loading and room temperature, without the need for excess glycidol or the presence of a solvent. Finally, these conditions and the best catalysts were successfully applied to the reaction of glycidol with several alcohols such as butanol or isopropanol.
- Pires, Elisabet,García, José Ignacio,Leal-Duaso, Alejandro,Mayoral, José Antonio,García-Peiro, José Ignacio,Velázquez, David
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- Synthesis of 3-alkoxypropan-1,2-diols from glycidol: Experimental and theoretical studies for the optimization of the synthesis of glycerol derived solvents
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A straightforward synthetic methodology has been derived for the synthesis of glycerol monoethers from glycidol and alcohols. Several homogeneous and heterogeneous basic catalysts have been tested, the best results being obtained with readily available and inexpensive alkaline metal hydroxides. In the best case, good yield of the desired monoether is obtained under smooth reaction conditions, always with total conversion of glycidol. The selectivity of the reactions mainly depends on the alcohol used, due to the concurrence of undesired side reactions. A mechanistic study carried out through computational DFT calculations, in which solvent effects are taken into account, also complemented the experiments, has allowed to identify the main reaction paths taking place under reaction conditions, giving insights into the main causes affecting the reaction selectivity and also into how it could be improved.
- Leal-Duaso,Caballero,Urriolabeitia,Mayoral,García,Pires
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p. 4176 - 4185
(2017/09/07)
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- Glycerol as a source of designer solvents: Physicochemical properties of low melting mixtures containing glycerol ethers and ammonium salts
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In this work we report the preparation of mixtures of several alkyl glyceryl ethers, as hydrogen bond donor compounds, with two ammonium salts, choline chloride and N,N,N-triethyl-2,3-dihydroxypropan-1-aminium chloride. The stability of the mixtures at different molar ratios and temperatures has been evaluated in order to determine the formation of low melting mixtures. Liquid and stable mixtures have been characterized and their physico-chemical properties such as density, viscosity, refractive index, conductivity and surface tension have been measured in the temperature range of 293.15 K to 343.15 K. Comparison of the mixtures prepared herein with the ones containing glycerol and choline chloride evidences the possibility of tuning the physico-chemical properties by changing the substitution pattern in the hydrogen bond donor compound or in the ammonium salt, thus broadening the scope of application of these mixtures.
- Leal-Duaso, Alejandro,Pérez, Pascual,Mayoral, José A.,Pires, Elisabet,García, José I.
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p. 28302 - 28312
(2017/11/06)
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- Synthesis of Monoalkyl Glyceryl Ethers by Ring Opening of Glycidol with Alcohols in the Presence of Lewis Acids
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The present work deals with the production of monoalkyl glyceryl ethers (MAGEs) through a new reaction pathway based on the reaction of glycidol and alcohols catalyzed by Lewis acid-based catalysts. Glycidol is quantitatively converted with high selectivity (99 %) into MAGEs under very mild reaction conditions (80 °C and 0.01 mol % catalyst loading) in only 1 h using Al(OTf)3 or Bi(OTf)3 as catalyst. The proposed method enhances the choice of possible green synthetic approaches for the production of value-added products such as MAGEs.
- Cucciniello, Raffaele,Ricciardi, Maria,Vitiello, Rosa,Di Serio, Martino,Proto, Antonio,Capacchione, Carmine
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p. 3272 - 3275
(2016/12/16)
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- Ecotoxicity studies of glycerol ethers in Vibrio fischeri: checking the environmental impact of glycerol-derived solvents
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The toxicities of a series of glycerol mono-, di-, and trialkyl ethers against Vibrio fischeri bacteria have been determined. A systematic study has been carried out and the possible structure-toxicity relationships have been discussed using different QSAR models. Inhibition of bioluminescence after 30 minutes of exposure shows relatively low toxicity of many of the glycerol derived chemicals studied. Results indicate that, as a general rule, the ecotoxicity increases with the length and number of substituents. However, if the size of the molecule increases, an extra substituent at position 2 makes the toxicity lower than that of the corresponding analogues.
- Garca,Pires,Aldea,Lomba,Perales,Giner
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supporting information
p. 4326 - 4333
(2015/08/11)
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- Synthesis of biodiesel without formation of free glycerol
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A new approach to the synthesis of biodiesel has been developed on the basis of alcoholysis of a triglyceride in combination with acetalization of glycerol with lower carbonyl compounds or acetals derived therefrom. A model synthesis of biodiesel not involving free glycerol has been accomplished using rapeseed oil and acid catalysts, as well as without a catalyst under generation of ethanol supercritical fluid; in the latter case, monoalkyl glycerol ethers are formed in addition to the expected cyclic ketals.
- Vol'eva,Belostotskaya,Komissarova,Koverzanova,Kurkovskaya,Usmanov,Gumerov
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p. 915 - 917
(2015/08/25)
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- Thermodynamic characteristics of the sorption of glycerol ethers on stationary phase OV-101
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Retention characteristics, temperature dependences of the retention characteristics, and thermodynamic characteristics of sorption on the nonpolar OV-101 phase are determined for 33 glycerol mono-, di-, and triethers with linear and branched monobasic alc
- Zhabina,Krasnykh,Levanova
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p. 1590 - 1593
(2014/10/16)
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- FUEL COMPOSITIONS COMPRISING HYDROPHOBIC DERIVATIVES OF GLYCERINE
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The object of the present invention relates to a composition that can be used as fuel comprising: at least one hydrocarbon mixture at least one hydrophobic ketal or acetal of glycerine. Said composition can be advantageously used as fuel for diesel or gasoline engines.
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Page/Page column 19
(2013/10/22)
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- EARLY STRENGTHENING AGENT FOR HYDRAULIC COMPOSITION
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This invention relates to an early strengthening agent for a hydraulic composition, which contains a compound (A) selected from a specific glycol ether-based compound and a specific glycerin derivate-based compound, as well as an additive composition for a hydraulic composition, which contains the early strengthening agent and a specific phosphate polymer (B).
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- Etherification of glycerol with ethanol over solid acid catalysts
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Different types of acidic heterogeneous catalysts, including sulfonic resins, zeolites and grafted silicas are used for the synthesis of mono-ethers of glycerol using ethanol as the alcohol. The study shows that the performances of the catalysts are governed by both the acidity and the polarity of their surface. Materials with strong hydrophobic character are not active as they do not allow the adsorption of the glycerol. On the other hand a strong adsorption of glycerol on the polar surfaces leads to low activity as well. The best compromise has been found by using sulfonic-acid polystyrene resins of the Amberlyst family and zeolites with intermediate aluminium contents.
- Pariente, Stephane,Tanchoux, Nathalie,Fajula, Franois
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scheme or table
p. 1256 - 1261
(2010/05/17)
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- Ultrafast and ultraslow oxygen atom transfer reactions between late metal centers
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Oxotrimesityliridium(V), (mes)3Ir=O (mes = 2,4,6- trimethylphenyl), and trimesityliridium(III), (mes)3Ir, undergo extremely rapid degenerate intermetal oxygen atom transfer at room temperature. At low temperatures, the two complexes conproportionate to form (mes) 3Ir-O-Ir(mes)3, the 2,6-dimethylphenyl analogue of which has been characterized crystallographically. Variable-temperature NMR measurements of the rate of dissociation of the μ-oxo dimer combined with measurements of the conproportionation equilibrium by low-temperature optical spectroscopy indicate that oxygen atom exchange between iridium(V) and iridium(III) occurs with a rate constant, extrapolated to 20 °C, of 5 × 107 M-1 s-1. The oxotris(imido) osmium(VIII) complex (ArN)3Os=O (Ar = 2,6-diisopropylphenyl) also undergoes degenerate intermetal atom transfer to its deoxy partner, (ArN) 3Os. However, despite the fact that its metal-oxygen bond strength and reactivity toward triphenylphosphine are nearly identical to those of (mes)3Ir=O, the osmium complex (ArN)3Os=O transfers its oxygen atom 12 orders of magnitude more slowly to (ArN)3Os than (mes)3Ir=O does to (mes)3Ir (kOsOs = 1.8 × 10-5 M-1 s-1 at 20 °C). Iridium-osmium cross-exchange takes place at an intermediate rate, in quantitative agreement with a Marcus-type cross relation. The enormous difference between the iridium-iridium and osmium-osmium exchange rates can be rationalized by an analogue of the inner-sphere reorganization energy. Both Ir(III) and Ir(V) are pyramidal and can form pyramidal iridium(IV) with little energetic cost in an orbitally allowed linear approach. Conversely, pyramidalization of the planar tris(imido)osmium(VI) fragment requires placing a pair of electrons in an antibonding orbital. The unique propensity of (mes)3Ir=O to undergo intermetal oxygen atom transfer allows it to serve as an activator of dioxygen in cocatalyzed oxidations, for example, acting with osmium tetroxide to catalyze the aerobic dihydroxylation of monosubstituted olefins and selective oxidation of allyl and benzyl alcohols.
- Fortner, Kevin C.,Laitar, David S.,Muldoon, John,Pu, Lihung,Braun-Sand, Sonja B.,Wiest, Olaf,Brown, Seth N.
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p. 588 - 600
(2007/10/03)
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- OH radical initiated photooxidation of 2-ethoxyethanol under laboratory conditions related to the troposphere: Product studies and proposed mechanism
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The products formed by the hydroxyl radical-initiated oxidation of 2- ethoxyethanol (CH3CH2OCH2CH2OH) have been investigated by irradiating synthetic air mixtures containing the substrate, methyl nitrite, and nitric oxide at ppm levels in a Teflon bag reactor at room temperature. The decay of reactants and the formation of products were monitored by gas chromatography and mass spectrometry. The major products ethyl formate [HC(O)OCH2CH3], ethylene glycol monaformate [HC(O)OCH2CH2OH], ethylene glycol monaacetate [CH3C(O)OCH2CH2OH], and ethoxyacetaldehyde [CH3CH2OCH2C(O)H] give a quantitative mass balance with the decay of the substrate molecule. The yields of these products were 34 ± 10%, 36 ± 7%, 7.8 ± 2.4%, and 24 ± 13%, respectively, in terms of percent of 2-ethoxyethanol removed by the OH radical. The product distribution is explained by a mechanism involving initial OH attack at the three CH2 groups in 2-ethoxyethanol followed by the subsequent reactions of the resulting alkyl and alkoxy radicals. The decomposition reactions of the alkoxy radicals from 2-ethoxyethanol, which can take place either by C-C or C-O bond breaking, involve preferential C-C cleavage rather than C-O cleavage. Rate coefficients at room temperature for the reactions of OH radicals with ethoxyacetaldehyde and 2-methyl-1,3- dioxolane (CH3CHOCH2CH2O, a minor product) have been determined to be 16.6 x 10-12 and 9.4 x 10-12 cm3 molecule-1 s-1, respectively.
- Stemmler, Konrad,Mengon, Wolfgang,Kerr, J. Alistair
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p. 3385 - 3391
(2007/10/03)
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- Reactions of 4-Chloromethyl-1,3-dioxolan-2-one with Phenols as a New Route to Polyols and Cyclic Carbonates
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Reaction of 4-chloromethyl-1,3-dioxolan-2-one (1) with phenol in the presence of potassium carbonate was studied and found to yield 4-phenoxymethyl-1,3-dioxolan-2-one (2) and 3-phenoxypropan-1,2-diol (3).The latter compound 3 was also found to be formed as the main product in the reaction of 1, phenol and sodium hydroxide at a temperature higher than 90 deg C.The effect of various factors on the reaction course and the yield of 2 and 3 was examined.It was found that the reaction studied can be extended to those of difunctional phenols such as 2,2-di(4-hydroxyphenyl) -propane producing the corresponding tetrahydroxyderivative - 2,2-bis-propane.
- Rokicki, G.,Pawlicki, J.,Kuran, W.
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p. 718 - 722
(2007/10/02)
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- SILICIUMORGANISCHE VERBINDUNGEN LXXII. SUBSTITUIERTE 1,3-DIOXA-2-SILA-CYCLOPENTANE
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Silylation of substituted dioles by means of hexamethyldisilazane leads to 2,2,7,7-tetramethyl-3,6-dioxa-2,7-disilaoctane derivatives.Reactions of these dioles with hexamethylcyclotrisilazane afford substituted 1,3-dioxa-2-silacyclopentanes.
- Birkofer, Leonhard,Stuhl, Oskar
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