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All total 90 Articles be found
All total 90 Articles be foundSynthesis of cyclic ethers from diols in the presence of copper catalysts
Bayguzina,Gimaletdinova,Khusnutdinov
, p. 1840 - 1843 (2017)
A number of cyclic ethers, namely tetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, oxepane, oxocane, and 1,4-oxathiane, have been synthesized in high yields by intramolecular dehydration of diols in the presence of copper-based catalysts.
Comyns,Lucas
, p. 1019 (1954)
Barnes, J. C.,Duncan, C. S.
, (1972)
Grunwald et al.
, p. 5801,5802, 5803 (1960)
Synthesis of 1,4-dioxene from diethylene glycol in the presence of bifunctional copper-containing catalysts. Effect of support on the selectivity of dioxene formation
Gitis,Neumoeva,Isagulyants
, p. 23 - 29 (1996)
In the synthesis of 1,4-dioxene from diethylene glycol in the presence of a bifunctional copper-containing catalyst, the composition of the by-products has been studied and the effect of the support on the overall direction of the reactions has been investigated. It has been established that on Cu/SiO2, 1,4-dioxanone is formed together with dioxene, the yield of the former increasing with an increase in the content of copper in the catalyst. This is due to an increase in the dehydrogenating function of the latter. On the more acidic Cu/Al2O3, 1,4-dioxane is mainly obtained together with, to a lesser degree, methyl-1,3-dioxolane. This is due to the predominance of dehydration reactions followed by isomerization. Dioxene, dioxane, and methyldioxolane are formed on Cu/HNaY, and the yield of the latter increases with an increase in the degree of acidity (degree of decationization) of the zeolite. It is possible to increase the selectivity of dioxene formation substantially with the use of a catalyst with a moderately acidic zeolite, by varying its copper content and by dilution with water vapor. 1996 Plenum Publishing Corporation.
Rheinboldt, H.
, p. 2535 - 2535 (1941)
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Tratremouille et al.
, p. 120,124 (1960)
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Transition metal triflate catalyzed conversion of alcohols, ethers and esters to olefins
Keskiv?li,Parviainen,Lagerblom,Repo
, p. 15111 - 15118 (2018/05/04)
Herein, we report an efficient transition metal triflate catalyzed approach to convert biomass-based compounds, such as monoterpene alcohols, sugar alcohols, octyl acetate and tea tree oil, to their corresponding olefins in high yields. The reaction proceeds through C-O bond cleavage under solvent-free conditions, where the catalytic activity is determined by the oxophilicity and the Lewis acidity of the metal catalyst. In addition, we demonstrate how the oxygen containing functionality affects the formation of the olefins. Furthermore, the robustness of the used metal triflate catalysts, Fe(OTf)3 and Hf(OTf)4, is highlighted by their ability to convert an over 2400-fold excess of 2-octanol to octenes in high isolated yields.
Synthesis of dioxolanes and oxazolidines by silica gel catalysis
Rohand, Taoufik,Savary, Jér?me,Markó, István E.
, p. 1429 - 1436 (2018/06/25)
Abstract: Ethylene glycol condensed with carbonyl compounds in the presence of silica gel or alumina, without solvent and under pressure, affords 1,3-dioxolanes. 2-Amino-2-methylpropanol also condensed with carbonyl compounds in the presence of silica gel or an acid-activated clay, without solvent and under pressure, produces oxazolidines. To explain these results, we propose that the glycol and the aminopropanol react with Br?nsted (H+) and Lewis acid sites (Si and Al) located on the surface of the catalysts, leading to the products via various ionic intermediates.
