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Tetrahydrofuran

About: Tetrahydrofuran is a research topic. Over the lifetime, 11778 publications have been published within this topic receiving 158241 citations. The topic is also known as: diethylene oxide & 1,4-epoxybutane.


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Journal ArticleDOI
TL;DR: In this paper, Triphenylmethyl methacrylate (TrMA) was polymerized with two types of asymmetric anionic catalyst, lithium (R)-N-(1-phenylethyl)anilide (LiAn) and (-)-sparteine-butyllithium complex (Sp-BuLi), at −78°C.
Abstract: Triphenylmethyl methacrylate (TrMA) was polymerized with two types of asymmetric anionic catalyst, lithium (R)-N-(1-phenylethyl)anilide (LiAn) and (-)-sparteine–butyllithium complex (Sp–BuLi), at −78°C. Both catalysts yielded optically active polymers. The polymers obtained with LiAn in toluene and tetrahydrofuran (THF) showed specific rotations [α] of from −50° to −90° (in THF). The [α] of the polymer obtained with Sp–BuLi in toluene was positive and increased with polymer yield reaching above +300°s, whereas the polymer obtained in THF showed a low [α] (ca. +7°). Gel permeation chromatograms of both polymers obtained with LiAn and Sp–BuLi in THF exhibited rather narrow molecular weight distributions, whereas those obtained in toluene showed at least two or three components with markedly different molecular weights. The circular dichroism (CD) spectrum of the polymer obtained with Sp–BuLi showed strong positive peaks at 208 and 232 nm and a weak band at 250–280 nm; the polymer produced with LiAn showed a similar spectrum with opposite sign. The poly(methyl methacrylate)s derived from these poly(TrMA)s were highly isotactic but showed negligible rotations ([α] ± 2° in toluene). The polymer of high molecular weight showed clear polarization under a polarizing microscope and the low polymer obtained with LiAn appeared to show flow birefringence in chloroform at room temperature.

84 citations

Journal ArticleDOI
TL;DR: In this paper, the lowest three-phase equilibrium pressure was obtained under the condition that the mole fraction of tetrahydrofuran in water is 0.056 and the Raman spectroscopy results showed that the H2 and CO2 molecules competitively occupied the S-cage of structure-II.
Abstract: Isothermal phase equilibria (pressure−composition in the gas phase) for the quaternary system of H2 + CO2 + tetrahydrofuran + water have been measured in the presence of gas hydrate phase. The lowest three-phase equilibrium pressure is obtained under the condition that the mole fraction of tetrahydrofuran in water is 0.056. The Raman spectroscopy results show that the H2 and CO2 molecules competitively occupy the S-cage of structure-II (i.e., the H2 molecule is enclathrated in the hydrate cages with a small amount of tetrahydrofuran at considerably low pressure).

84 citations

Journal ArticleDOI
TL;DR: In this paper, the authors show that gas-expanded liquids under CO2 pressure are unique media for amine formation and separation and demonstrate the potential for using modest pressures of CO2 to facilitate reactions as well as to separate products.
Abstract: Gas-expanded liquids are tunable media for reaction and separation. We report that gas-expanded liquids under CO2 pressure are unique media for amine formation and separation. In the heterogeneous hydrogenation of benzonitrile and phenylacetonitrile with NiCl2/NaBH4 in CO2-expanded ethanol, the primary amines are protected by CO2 so that the yield of the primary amines is greatly increased and the production of the secondary amines is effectively suppressed. In the homogeneous hydrogenation of benzonitrile and phenylacetonitrile with RhH(P-i-Pr3)3 and benzophenone imine with Rh(1,5-C8H12){P(C6H5)3}2]PF6 in CO2-expanded tetrahydrofuran, the primary amines are separated in situ in the form of solid carbamic acids and/or ammonium carbamates with increased yield while the catalyst remains in the solution. These results demonstrate the potential for using modest pressures of CO2 to facilitate reactions as well as to separate products.

83 citations

Journal ArticleDOI
15 May 2002-Langmuir
TL;DR: The noncatalytic destructive adsorption of 2-chloroethyl)ethyl sulfide (2-CEES) on nanocrystalline magnesium oxide (MgO) was studied in several solvents from pentane to methanol as mentioned in this paper.
Abstract: The noncatalytic destructive adsorption of (2-chloroethyl)ethyl sulfide (2-CEES), a mimic of bis(2-chloroethyl) sulfide (“HD” or Mustard Gas), on nanocrystalline magnesium oxide (AP-MgO) was studied in several solvents from pentane to methanol. The decomposition products formed in these reactions were vinylethyl sulfide and (2-hydroxyethyl)ethyl sulfide. Reactions in pentane allowed the highest reaction rates, while tetrahydrofuran (THF) and methanol gave results quite different from those for the hydrocarbon solvent. Reactions in methanol yielded (methoxyethyl)ethyl sulfide and not the vinylethyl sulfide and (2-hydroxyethyl)ethyl sulfide compounds. These studies showed that the MgO-2-CEES reaction chemistry is significantly affected by the solvent present and can be enhanced by choice of solvent and the addition of small amounts of water. Interestingly, the least polar, least reactive solvent (pentane) allowed the most rapid 2-CEES reactions, indicating that the solvent simply aided material transfer to ...

83 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023194
2022382
2021124
2020154
2019193
2018218