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.

Identification of Surface Films Formed on Lithium in Dimethoxyethane and Tetrahydrofuran Solutions

Abstract: Surface films formed on lithium metal in dimethoxyethane (DME) and tetrahydrofuran (THF) solutions of ,, and were analyzed using FTIR, SIMS, and XPS spectroscopies. The films formed in both solvents were found to contain lithium alkoxides. The main reaction products detected with FTIR were in DME, and in THF. SIMS measurements are consistent with this finding. Reaction mechanisms are discussed. When the water concentration in these systems is 0.01M or greater, is formed on the lithium surface and appears to be a major component in the surface films. XPS measurements gave evidence for simultaneous salt reduction on the lithium surface in addition to the solvent reactions.

Strategies for the analysis of polar solvents in liquid matrixes.

Abstract: Various approaches to the analysis of polar compounds in different matrixes by solid-phase microextraction (SPME) were studied. The analysis of polar analytes in nonpolar matrixes was performed with custom-made SPME fibers coated with Nafion perfluorinated resin. The sensitivity of this fiber in this type of analysis was better by 1 order of magnitude on average as compared to those of any of the commercially available fibers. The fiber was the most sensitive for the most polar of the compounds studied, i.e., methanol. Determination of methanol, ethanol, and 2-propanol in unleaded gasoline was illustrated. Except for methanol, the fiber did not perform very well in the analysis of alcohols in water. The fiber was capable of extracting water from benzene. SPME analysis of polar compounds in water was studied using aqueous solutions of acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), 2-propanol, 2-methyl-2-propanol, and tetrahydrofuran. Fibers coated with poly(dimethylsiloxane)/divinylbenzene yi...

Proposals for structure and effect of methylalumoxane based on mass balances and phase separation experiments

Abstract: Methylaluminoxane prepared from trimethylaluminium on a surface of ice mainly can be described as [Al4O3(CH3)6]4. This is shown through analysis, phase separation experiments with diethyl ether and molecular weight determinations in benzene, 1, 4-dioxane, tetrahydrofuran and trimethylaluminium. It is discussed that the reason for forming this ball-like structure is the saturation of four coordinated Al4O3(CH3)6. This molecule has a cavern which contains a solvent molecule or a molecule of trimethylaluminium. The consequences for the formation of the catalytically active structure together with metallocene are discussed.

Complex Crystal Formation of Poly(l-lactide) with Solvent Molecules

Abstract: By screening examinations for a wide variety of organic solvents, we found that poly(l-lactide) (PLLA) forms the crystalline complex (e-form) with the specific organic solvents such as tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) below room temperature. It was revealed that PLLA has high selectivity for low molecular weight compounds to form the e-crystals. By fiber diagram analyses for the e-forms, it was found that PLLA chains take the 107 (left-handed 103) helical conformation and are packed in the orthorhombic lattice (a = 1.5–1.6 nm, b = 1.2–1.3 nm, c = 2.8–2.9 nm, and α = β = γ = 90°). Based on R-factor and packing energy calculations, the plausible crystal structure of PLLA–DMF complex was proposed, in which four PLLA chains and eight guest solvents are packed in the unit cell.