- Graphite oxide: A simple and efficient solid acid catalyst for the ring-opening of epoxides by alcohols
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A simple, efficient, and general procedure for the ring-opening of epoxides with various alcohols to give the corresponding β-alkoxy alcohols using graphite oxide (GO) as the catalyst, under very mild reaction conditions is described. The method proceeds in good to excellent yields and in short reaction times at room temperature under metal-free conditions.
- Mirza-Aghayan, Maryam,Alizadeh, Mahdi,Molaee Tavana, Mahdieh,Boukherroub, Rabah
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- Epoxide ring opening with alcohols using heterogeneous Lewis acid catalysts: Regioselectivity and mechanism
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Lewis acidic catalytic materials are investigated for the regioselective ring opening of epoxides with alcohols. For ring opening epichlorohydrin with methanol, the catalytic activity shows a strong dependence on the type of support and Lewis acidic species used. While Sn-SBA-15 is catalytically active, significantly higher catalytic activity can be achieved with hydrothermally synthesized zeolites of which Sn-Beta is 6 and 7 times more active than Zr-Beta or Hf-Beta, respectively. Sn-Beta is determined to be more active and more regioselective for epoxide ring opening of epichlorohydrin with methanol than Al-Beta. For Sn-Beta, the activation energy for the reaction between epichlorohydrin and methanol is determined to be 53 ± 7 kJ mol?1. For epichlorohydrin, the activation energy barrier and experimentally observed regioselectivity are found using DFT to be consistent with a concerted reaction mechanism involving activation of the epoxide on an alcohol adsorbed on the catalytic site and nucleophilic attack by a second alcohol. The epoxide is shown to impact the regioselectivity and the mechanism since isobutylene oxide is selectively ring opened by methanol to form the terminal alcohol. DFT calculations indicate the mechanism for isobutylene ring opening involves epoxide activation and ring opening on an alcohol adsorbed onto the catalytic site. Finally, catalyst reuse testing indicates that Sn-Beta can be used for multiple reactions with no decrease in activity and limited to no leaching of the tin site, demonstrating Sn-Beta is a promising catalytic material for epoxide ring opening reactions with alcohols.
- Deshpande, Nitish,Parulkar, Aamena,Joshi, Rutuja,Diep, Brian,Kulkarni, Ambarish,Brunelli, Nicholas A.
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- Polyoxometalate-modified reduced graphene oxide foam as a monolith reactor for efficient flow catalysis of epoxide ring-opening reactions
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Continuous flow catalysis has been attracting significant interest due to its remarkable advantages over traditional batch reactions. In this work, a facile and broad-spectrum hydrothermal approach has been developed to construct polyoxometalate-modified reduced graphene oxide (POM@rGO) foam, which worked as a monolith reactor for efficient continuous flow catalysis of epoxide ring-opening reactions. The porous structures of rGO foam allow the high dispersion of the POM catalyst onto the substrate through electrostatic interactions. Specifically, a phosphotungstic acid (H3PW12O40, denoted as PW12)-modified rGO (PW12@rGO) monolith reactor exhibits remarkable catalytic activity and durability towards epoxide ring-opening reactions with alcohols, achieving 99% conversion and 92% selectivity for the methanolysis product in 10 min under ambient conditions without stirring. Notably, while coupling with a micro-injection pump, such PW12@rGO foam can work as an efficient continuous flow reactor towards methanolysis of styrene oxide for 38 h with 99% conversion and over 90% selectivity, reaching a turnover number (TON) as high as 28?044.
- Jing, Xiaoting,Li, Zhen,Geng, Weijie,Lv, Hongjin,Chi, Yingnan,Hu, Changwen
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- PERFUMES IN THE FORM OF AQUEOUS MICROEMULSIONS
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An oil-in-water microemulsion including, in weight percentages: between 70% and 94% of water; between 1% and 15% of at least one perfumed hydrophobic substance; between 4% and 20% of at least one preferably volatile solvo-surfactant, which is a monoalkylated glycerol derivative of formula (I); and between 0.1% and 15% of at least one anionic surfactant and at least one alkyl glucoside as a hydrotropic agent. The microemulsion can therefore be used to produce a fine fragrance composition or a cosmetic or personal hygiene composition.
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Paragraph 0104-0107
(2020/07/04)
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- PERFUMES IN THE FORM OF AQUEOUS MICROEMULSIONS
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Disclosed is a microemulsion of oil-in-water type including, preferably consisting of, by weight relative to the total weight of microemulsion: ? 70% to 94% of water, ? 1% to 15% of at least one hydrophobic fragrancing substance, ? 4% to 20% of at least one preferably volatile solvo-surfactant, and ? 0.1% to 15%, preferably 1% to 13%, of at least one hydrotropic agent or at least one surfactant selected from anionic surfactants, cationic surfactants, amphoteric surfactants and non-ionic surfactants. The solvo-surfactant is selected from monoalkylated glycerol derivatives of following formula (I): wherein the “alkyl” group is a linear or branched alkyl group including from 1 to 8 carbon atoms, and R and R′ are each independently H or a linear or branched alkyl group including from 1 to 5 carbon atoms, with the proviso that R is different from R′, and mixtures thereof.
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Paragraph 0136; 0141-0145
(2020/11/30)
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- Readily Scalable Methodology for the Synthesis of Nonsymmetric Glyceryl Diethers by a Tandem Acid-/Base-Catalyzed Process
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A useful optimized synthetic methodology has been designed for the synthesis of nonsymmetric glyceryl diethers from epichlorohydrin. A tandem process combining a cheap, heterogeneous, and fully recoverable acid catalyst and alkaline hydroxide is used for the synthesis of a variety of glycerol-derived ethers bearing different alkyl substituents in 1 and 3 positions. Different heterogeneous acid catalysts have been tested for the reaction of epichlorohydrin with several alcohols, the best results being obtained with readily available recoverable and inexpensive montmorillonite-K10 and Nafion NR50. For the second reaction step, potassium hydroxide is used. In all the cases, good yields of the desired glyceryl diethers are obtained in smooth reaction conditions, always with total conversion of epichlorohydrin and without the need of intermediate purification. Scale-up of the tandem process has been carried out with good results.
- Leal-Duaso, Alejandro,Gracia-Barberán, Sara,Mayoral, José A.,Garciá, José I.,Pires, Elisabet
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p. 154 - 162
(2020/02/04)
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- An Fe3O4 nanoparticle-supported Mn (II)-azo Schiff complex acts as a heterogeneous catalyst in alcoholysis of epoxides
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In this paper, an azo-containing Schiff base complex of manganese [Mn2+-azo ligand@APTES-SiO2@Fe3O4] immobilized on chemically modified Fe3O4 nanoparticles has been used as a magnetically retrievable catalyst for the alcoholysis of different epoxides to their corresponding alkoxy alcohols with methanol, ethanol and n-propanol. The newly magnetic nanoparticles (MNPs) were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and vibrating sample magnetometry (VSM).
- Olia, Fahimeh Karami,Sayyahi, Soheil,Taheri, Narges
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p. 370 - 376
(2017/03/15)
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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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- Green solvents from glycerol. Synthesis and physico-chemical properties of alkyl glycerol ethers
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A family of glycerol derivatives, consisting of over sixty 1,3-dialkoxy-2-propanols and 1,2,3-trialkoxypropanes, both symmetrically and unsymmetrically substituted at terminal positions, have been synthesized and the possible role of these glycerol derivatives as substitutive solvents has been evaluated through measurements of their physico-chemical properties. The molecular diversity of the derivatives prepared results in significant variations of polarity properties, facilitating the identification of possible candidates for solvent substitution.
- Garcia, Jose I.,Garcia-Marin, Hector,Mayoral, Jose A.,Perez, Pascual
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experimental part
p. 426 - 434
(2010/08/07)
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- Silica sulfuric acid; an efficient and reusable catalyst for regioselective ring opening of epoxides by alcohols and water
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The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of silica sulfuric acid with high degree of regioselectivity. The catalyst is reusable and can be applied several times without any decrease in the yield of reactions.
- Salehi, Peyman,Dabiri, Minoo,Zolfigol, Mohammad Ali,Fard, Mohammad Ali Bodaghi
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p. 1113 - 1121
(2007/10/03)
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- Magnesium hydrogensulfate: A cheap and efficient catalyst for the conversion of epoxides into β-alkoxy alcohols, vicinal-diols, and thiiranes
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The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of magnesium hydrogensulfate, Mg(HSO4)2, with high degree of regioselectivity. The reactions are chemoselective and many of the other functional groups such as ethereal carbon oxygen bonds as well as carbon-carbon double bond remain intact under the reaction conditions. Epoxides also react with thiourea or ammonium thiocyanate in the presence of Mg(HSO 4)2 to afford the corresponding thiiranes in good to excellent yields.
- Salehi, Peyman,Khodaei, Mohammad Mahdi,Zolfigol, Mohammad Ali,Keyvan, Afsaneh
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p. 3041 - 3048
(2007/10/03)
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- Iron perchlorate on silica gel as multi-purpose reagent for catalysis of closure and rupture of carbon-oxygen bond in epoxides, alcohols, and esters
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Aliphatic alcohols and water in the presence of catalytic amounts of Fe3+ ion introduced as iron(III) perchlorate on silica gel carrier perform efficient regiospecific opening of an epoxy ring. Carbon acids esterification with various type alcohols was carried out using the system Fe(ClO4)3-silica gel in dichloromethane under conditions excluding solvolysis. Acetylation and formylation of alcohols was performed by efficient transesterification with ethyl acetate and ethyl formate.
- Salechi,Khodaei,Ghareghani,Motlagh
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p. 794 - 796
(2007/10/03)
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