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Catalytic Epoxidation of Limonene  [PDF]
E. Herrero,S. Casuscelli,J. Fernandez,C. Poncio,M. Rueda,O. Oyola
Molecules , 2000, DOI: 10.3390/50300336
Abstract: The epoxidation of limonene with hidrogen peroxide was studied over zeolite Tibeta (a large pore material) and heteropoly acids on carbono and alumina supported. PW11/C was catalyst the best tested.
Heterogenization of alkene epoxidation catalysts
Buffon, Regina;Schuchardt, Ulf;
Journal of the Brazilian Chemical Society , 2003, DOI: 10.1590/S0103-50532003000300002
Abstract: this account describes our efforts to heterogenize epoxidation catalysts. anchored and sol-gel entrapped molybdenum were shown to be very selective, but had a strongly reduced activity. on the other hand, molybdenum silicates were very active and stable as long as no diols were present in the reaction mixture. heterogenized rhenium catalysts were less active but allowed the use of anhydrous hydrogen peroxide as oxidant. however, the high cost and difficult regeneration prevents the industrial use of these catalysts. during these investigations, we found that alumina alone is active in the epoxidation with anhydrous hydrogen peroxide, giving good conversions to epoxides with high selectivity. more research is needed in order to clarify the nature of the hydroxyl groups responsible for its catalytic activity and thus to produce an appropriate material which would allow the obtention of epoxides with high selectivity under industrial conditions.
Heterogenization of alkene epoxidation catalysts  [cached]
Buffon Regina,Schuchardt Ulf
Journal of the Brazilian Chemical Society , 2003,
Abstract: This account describes our efforts to heterogenize epoxidation catalysts. Anchored and sol-gel entrapped molybdenum were shown to be very selective, but had a strongly reduced activity. On the other hand, molybdenum silicates were very active and stable as long as no diols were present in the reaction mixture. Heterogenized rhenium catalysts were less active but allowed the use of anhydrous hydrogen peroxide as oxidant. However, the high cost and difficult regeneration prevents the industrial use of these catalysts. During these investigations, we found that alumina alone is active in the epoxidation with anhydrous hydrogen peroxide, giving good conversions to epoxides with high selectivity. More research is needed in order to clarify the nature of the hydroxyl groups responsible for its catalytic activity and thus to produce an appropriate material which would allow the obtention of epoxides with high selectivity under industrial conditions.
LIGNIN MODIFICATION BY EPOXIDATION  [PDF]
Theodor Malutan,Raluca Nicu,Valentin I. Popa
BioResources , 2008,
Abstract: The chemical modification of lignin through hydroxymethylation and epoxidation is a way to develop new application fields and improvement of lignin performances. In this paper the influence of reaction conditions was studied using different samples of unmodified and modified lignins from annual plants (Wheat straw and Sarkanda grass). The progress of reactions was monitored by evaluating the epoxy index. The resulting products were characterized by FTIR-spectra, UV-Vis spectroscopy, and thermogravimetry analysis. The products obtained were tested to be used in composite formulation for wood applications.
Ethylmethyldioxirane epoxidation of Plukenetia cononophora oil
E.T. Akintayo
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: Epoxidation of Plukenetia conophora oil by ethylmethyldioxirane has been studied. The epoxidation reaction was best accomplished using the Curci’s biphasic method employing 2-butanone as the solvent. Spectroscopic techniques (IR, 1H NMR and 13C NMR) indicated complete conversion of double bonds to epoxy groups. Overall, OxoneTM can be said to be an inexpensive oxidant that is easily handled and with demonstrated utility in preparing epoxidised oils from natural triglycerides. KEY WORDS: Plukenetia conophora oil, Epoxidation, Ethylmethyldioxirane, OxoneTM Bull. Chem. Soc. Ethiop. 2007, 21(1), 95-102.
Ethylmethyldioxirane epoxidation of Plukenetia cononophora oil  [cached]
E.T. Akintayo
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: Epoxidation of Plukenetia conophora oil by ethylmethyldioxirane has been studied. The epoxidation reaction was best accomplished using the Curci’s biphasic method employing 2-butanone as the solvent. Spectroscopic techniques (IR, 1H NMR and 13C NMR) indicated complete conversion of double bonds to epoxy groups. Overall, OxoneTM can be said to be an inexpensive oxidant that is easily handled and with demonstrated utility in preparing epoxidised oils from natural triglycerides.
Asymmetric epoxidation of α,β-unsaturated ketones using α,α-diarylprolinols as catalysts
ChangWu Zheng,Gang Zhao
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-3129-0
Abstract: Asymmetric epoxidation of α,β-unsaturated ketones has been extensively studied and several important procedures have been developed in the last decade. This review addresses the most significant advances in asymmetric epoxidation of α,β-unsaturated ketones using proline-derived α,α-diarylprolinols as catalysts. Special attention has been paid to the enantioselective epoxidation of chalcones, α,β-unsaturated trifluoromethyl, trichloromethyl ketones and β,γ-unsaturated α-keto esters based on the reseach of our group.
Epoxidation of Cyclohexene on Heterogenized Molybdenum Compounds
Barradas, E.F.M.;Cestari, A.R.;Airoldi, C.;Buffon, R.;
Brazilian Journal of Chemical Engineering , 1998, DOI: 10.1590/S0104-66321998000200008
Abstract: heterogenization of molybdenum species, starting either with mo(co)6 or moo2(acac)2, on the surface of functionalized silicas bearing one (si-et1) or two (si-et2) ethylenediamine ligands was studied. the resulting systems are active in the catalytic epoxidation of cyclohexene by tert-butyl hydroperoxide. using fresh catalysts, si-et2 results in higher selectivity, regardless of the mo precursor. however, moo2(acac)2-based systems are far more active. formation of diols was never detected. although xps analyses point mainly to mo(vi) species on the surface of all systems, uv-vis spectra suggest different ligands in their coordination sphere
Epoxidation of Cyclohexene on Heterogenized Molybdenum Compounds  [cached]
Barradas E.F.M.,Cestari A.R.,Airoldi C.,Buffon R.
Brazilian Journal of Chemical Engineering , 1998,
Abstract: Heterogenization of molybdenum species, starting either with Mo(CO)6 or MoO2(acac)2, on the surface of functionalized silicas bearing one (Si-Et1) or two (Si-Et2) ethylenediamine ligands was studied. The resulting systems are active in the catalytic epoxidation of cyclohexene by tert-butyl hydroperoxide. Using fresh catalysts, Si-Et2 results in higher selectivity, regardless of the Mo precursor. However, MoO2(acac)2-based systems are far more active. Formation of diols was never detected. Although XPS analyses point mainly to Mo(VI) species on the surface of all systems, UV-vis spectra suggest different ligands in their coordination sphere
Kinetics of the Epoxidation of Geraniol and Model Systems by Dimethyldioxirane  [PDF]
A. L. Baumstark,P. J. Franklin,P. C. Vasquez,B. S. Crow
Molecules , 2004, DOI: 10.3390/90300117
Abstract: The mono-epoxidation of geraniol by dimethyldioxirane was carried out invarious solvents. In all cases, the product ratios for the 2,3 and 6,7 mono-epoxides werein agreement with literature values. Kinetic studies were carried out at 23 oC in thefollowing dried solvent systems: acetone (k2 = 1.49 M-1s-1), carbon tetrachloride/acetone(9/1, k2=2.19 M-1s-1), and methanol/acetone (9/1, k2 = 17 M-1s-1). Individual k2 valueswere calculated for epoxidation of the 2,3 and 6,7 positions in geraniol. The non-conjugated diene system was modeled employing two simple independent alkenes:2-methyl-2-pentene and 3-methyl-2-buten-1-ol by determining the respective k2 valuesfor epoxidation in various solvents. The kinetic results for each independent alkeneshowed that the relative reactivity of the two epoxidation sites in geraniol as a function ofsolvent was not simply a summation of the independent alkene systems.
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