112-61-8Relevant articles and documents
Selectivity in sorption and hydrogenation of methyl oleate and elaidate on MFI zeolites
Philippaerts, An,Paulussen, Sabine,Turner, Stuart,Lebedev, Oleg I.,Van Tendeloo, Gustaaf,Poelman, Hilde,Bulut, Metin,De Clippel, Filip,Smeets, Pieter,Sels, Bert,Jacobs, Pierre
, p. 172 - 184 (2010)
Different zeolites were tested for selective removal of methyl elaidate (trans isomer) from an equimolar mixture with methyl oleate (cis isomer). Sorption experiments of the geometric isomers show that only ZSM-5 samples with reduced Al content in the framework are able to discriminate among the bent cis and the linear trans fatty acid methyl esters. Hydrogenation experiments of equimolar methyl oleate and elaidate mixtures at low temperature (65 °C) and high hydrogen pressure (6.0 MPa), using Pt catalysts, confirm this result. Only with a Pt/Na-ZSM-5 catalyst outspoken selectivity for the hydrogenation of the trans isomer is obtained. In order to prepare a selective Pt/ZSM-5 catalyst, the influence of Pt addition (impregnation, ion-exchange and competitive ion-exchange) and Pt activation (different calcination and reduction temperatures) on the Pt-distribution and Pt particle size was investigated using SEM, bright-field and HR TEM, EDX, electron tomography, CO-chemisorption, XPS, XRD, and UV-vis measurements. The best result in terms of hydrogenation activity and selectivity is obtained with a Pt/ZSM-5 catalyst, which is prepared via competitive ion-exchange, followed by slow calcination up to 350 °C under high O2 flow and a reduction up to 500 °C under H2. This preparation method leads to a Pt/ZSM-5 catalyst with the best Pt distribution and the smallest Pt clusters occluded in the zeolite structure. Finally, the influence of zeolite crystal size, morphology, and elemental composition of ZSM-5 on hydrogenation activity and selectivity was investigated in detail.
A new reagent for the methylation of carboxyl groups
Siddiqui, Bina S.,Firdous,Begum, Sabira
, p. 9059 - 9060 (2001)
A new reagent for the preparation of methyl esters of carboxylic acids is described. The reaction involves treatment of acids with methanesulfonyl chloride in pyridine at 0°C.
Synthesis and characterization of composites based on polyaniline and styrene-divinylbenzene copolymer using benzoyl peroxide as oxidant agent
Moura,Assis,Franco,Antoniosi Filho,Rabelo
, p. 1255 - 1261 (2013)
This work presents a method to prepare composites based on polyaniline (Pani) and styrene-divinylbenzene copolymers (SD) by in situ polymerization of aniline using benzoyl peroxide as oxidant agent. The composites were obtained from copolymers with two degrees of porosities which have higher and lower surface areas. Emeraldine Pani was prepared using hydrochloric acid as dopant. One cycle or four cycles of aniline polymerization were performed. The copolymers and their respective composites characterizations were performed by infrared spectroscopy, thermogravimetric analysis, physical nitrogen adsorption-desorption measurements, morphology analysis, elemental analysis and determination of Br?nsted acid sites. The Pani was distributed overall porous SD copolymer producing composites with high surface area. Then, they were evaluated as catalysts for esterification reaction of a fat acid. It was found that that composites prepared with four cycles of in situ polymerization presented best catalytic activity than one cycle composites.
The dichapetalins - A new class of triterpenoids
Addae-Mensah, Ivan,Waibel, Reiner,Asunka, Stephen A.,Oppong, Isaac V.,Achenbach, Hans
, p. 649 - 656 (1996)
Further to our recent report on dichapetalin A, we describe the isolation and structure elucidation by spectroscopic methods of dichapetalins B-H from the roots of Dichapetalum madagascariense. These compounds constitute a novel class of triterpenoids. Dichapetalin A shows a strong and selective cytotoxic activity.
Comparison of phosphatidylcholine vesicle properties related to geometrical isomerism
Ferreri, Carla,Pierotti, Silvia,Barbieri, Andrea,Zambonin, Laura,Landi, Laura,Rasi, Silvia,Luisi, Pier Luigi,Barigelletti, Francesco,Chatgilialoglu, Chryssostomos
, p. 274 - 280 (2006)
Glycerophosphatidylcholine containing trans-unsaturated fatty acid residues was prepared by reaction of the corresponding naturally occurring cis lipid with photochemically generated thiyl radicals. This modified lipid was chosen as the simplest model for gaining some insights of the complex scenario of membrane formation, in connection with the role of lipid geometry and the predominance of cis lipids in eukaryotic cells. The critical aggregation concentration for the spontaneous formation of vesicles was determined for cis and trans isomers with cis-parinaric acid used as a fluorescent probe and it was found to be similar for both lipids. Vesicle dimensions were investigated by light scattering and electron microscopy, and the type of fatty acid residues influenced the vesicle diameter, with a decrease along the series cis > trans > saturated. Fluorescence measurement of dye release from trans and cis vesicles showed also a different permeability. A picture emerged of the geometrical isomer preference in cells as a process driven by natural selection during the life evolution of different organisms, both in terms of compartment dimensions and membrane functionality.
HYDROGENATION OF FATTY ACIDS ESTERS. III. HYDROGENATION OF METHYL (9Z,12Z)-OCTADECADIENOATE AND METHYL (9Z,12Z,15Z)-OCTADECATRIENOATE
Krupickova, Jana,Vcelak, Jaroslav,Hetflejs, Jiri
, p. 2593 - 2604 (1992)
The title hydrogenation catalyzed by nickel(II) 2,4-pentanedionate-triethylaluminium system has been studied with the use of combination of initial rate measurements with time changes of product distribution.It was found that the hydrogenation of methyl (9Z,12Z)-octadecadienoate is first order in the octadecadienoate.Similar results were obtained also for (9Z,12Z,15Z)-octadecatrienoate.The course of both reactions has been described by models involving set of parallel and consecutive hydrogenation steps and reversible isomerizations.Computer rate constants for hydrogenation of methyl (9Z,12Z)-octadecadienoate support qualitative conclusions deduced from the product analysis.
Mesoporous RuO2/TiO2 composites prepared by cyclodextrin-assisted colloidal self-assembly: Towards efficient catalysts for the hydrogenation of methyl oleate
Bleta, Rudina,No?l, Sébastien,Addad, Ahmed,Ponchel, Anne,Monflier, Eric
, p. 14570 - 14579 (2016)
Mesoporous RuO2/TiO2 composites were prepared using a template-directed colloidal self-assembly approach combined with a cyclodextrin (CD)-assisted aqueous impregnation method. The supramolecular assemblies formed between the randomly methylated β-cyclodextrin (RaMeβ-CD) and the block copolymer P123 acted as a template for the formation of a highly porous TiO2 network over which uniform dispersion of ruthenium nanoparticles was achieved. By combining dynamic light scattering, X-ray diffraction, N2-adsorption, temperature-programmed reduction, field-emission scanning electron microscopy and high-resolution transmission electron microscopy, we show that CD-based assemblies provide a versatile and easily accessible toolbox with different functionalities for generating metal-supported catalysts with controlled pore architecture and uniform metal distribution. The performance of these supported catalysts was evaluated in the liquid phase hydrogenation of methyl oleate (MO, C18:1) to methyl stearate (MS, C18:0). Control of ruthenium dispersion into the large pores of RaMeβ-CD-P123-templated TiO2 material enhanced catalyst activity and selectivity for the hydrogenation of the internal C = C bond and permitted catalyst separation and reuse without loss of activity. Our findings highlight the pivotal role played by the CD-based assemblies on the performance of supported ruthenium catalysts.
Chromatographic analyses of fatty acid methyl esters by HPLC-UV and GC-FID
Carvalho, Myller S.,Mendonc?a, Ma?rcio A.,Pinho, David M. M.,Resck, Ine?s S.,Suarez, Paulo A. Z.
, p. 763 - 769 (2012)
An analytical method using high performance liquid chromatography with UV detection (HPLC-UV) (method A) was used for simultaneous determination of total amounts of triacylglycerides, diacylglycerides, monoacylglycerides and fatty acid methyl esters in alcoholysis of different oil (cotton, canola, sunflower, corn and soybean) samples. Analyses were carried out at 40 °C for 20 min using a gradient of methanol (MeOH) and 2-propanol-hexane 5:4(v/v) (PrHex):100percent of MeOH in 0 min, 50percent of MeOH and 50percent of PrHex in 10 min maintained with isocratic elution for 10 min. Another HPLC-UV method (method B) with acetonitrile isocratic elution for 34 min was used to determine the fatty acid composition of oils analyzing their methyl ester derivatives. Contents were determined with satisfactory repeatability (relative standard deviation, RSD 2 > 0.99) and sensitivity (limit of quantification). Method B was compared with an official gas chromatographic method with flame ionization detection (GC-FID) from American Oil Chemists' Society (AOCS) in the determination of fatty acid methyl esters (FAME) in biodiesel real samples.
AN ACYLATED SITOSTEROL GLUCOSIDE FROM ALISMA PLANTAGO-AQUATICA
Pei-Wu, Geng,Fukuyama, Yoshiyasu,Rei, Wang,Jinxian, Bao,Nakagawa,Kazuyuki
, p. 1895 - 1896 (1988)
A phytosterol glucoside acylated with stearic acid has been isolated from the methanol extract of the rhizome of Alisma Plantago-aquatica, and its structure has been determined as sitosterol-3-O-6-stearoyl-β-D-glucopyranoside by spectroscopic data and chemical conversions.Key Word Index-Alisma Plantago-aquatica; Alismataceae; sitosterol-3-O-6-stearoyl-β-D-glucopyranoside; sitosterol; methyl stearate.
A direct novel synthesis of highly uniform dispersed ruthenium nanoparticles over P6mm ordered mesoporous carbon by host-guest complexes
Gokulakrishnan,Peru,Rio,Blach,Leger,Grosso,Monflier,Ponchel
, p. 6641 - 6648 (2014)
We report a novel concept to prepare a highly ordered mesoporous carbon with a uniform dispersion of ruthenium nanoparticles of 1-2 nm size range using a nano-templating method, based on the combined utilization of a β-cyclodextrin host-guest complex and ruthenium trichloride as respective sources of carbon and metal. The composite material synthesized (Ru@MCA-2) through the polymerization and carbonization of these metallo-supramolecular assemblies possesses high surface area and high pore volume after the removal of the silica template and exhibits high catalytic activity in the hydrogenation of unsaturated fatty acid methyl esters. The reusability of this nanoreplicated catalyst is also demonstrated. This journal is the Partner Organisations 2014.
