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.

A Cyclic Macromonomer Designed for a Novel Polymer Network Architecture Having Both Covalent and Physical Linkages

Abstract: A methacrylate-functionalized, cyclic poly(tetrahydrofuran), poly(THF) (1m), has been synthesized and copolymerized through a free-radical mechanism involving methyl methacrylate (MMA) and using 2,2'-azobisisobutyronitrile as the initiator in benzene at 65 °C. A copolymer product with cyclic poly(THF) branches was produced initially, with gelation taking place at a later stage of the reaction. In contrast, no gelation was observed either in the quantitative-conversion copolymerization of a related methacrylate-functionalized, open-chain poly(THF) with MMA or in the quantitative homopolymerization of MMA in the presence of a methacrylate-free, cyclic poly(THF). These results demonstrate that the propagating polymer segment threaded the large but constrained cyclic polymer branches covalently attached to the polymer backbone, to produce a novel polymer network architecture having both covalent and physical linkages.

Phase Equilibria of Clathrate Hydrates of Tetrahydrofuran + Hydrogen Sulfide and Tetrahydrofuran + Methane

Abstract: In this work, experimental dissociation data for the clathrate hydrates of tetrahydrofuran + hydrogen sulfide and tetrahydrofuran + methane are reported. The experimental data were generated using an isochoric pressure-search method. The dissociation data for the tetrahydrofuran + methane clathrate hydrates are compared with the corresponding experimental data reported in the literature, and the acceptable agreement demonstrates the reliability of the experimental method used in our work. Moreover, we extend the literature data for the latter system to a low concentration of tetrahydrofuran in its aqueous solution. As addition of high concentrations of tetrahydrofuran in aqueous solution diminishes its pressure-reducing effect, we therefore measured and report the experimental dissociation data for the tetrahydrofuran + hydrogen sulfide clathrate hydrates at low concentrations of tetrahydrofuran in its aqueous solution.

Polymerization of ethylene oxide with a calixarene-based precursor: Synthesis of eight-arm poly(ethylene oxide) stars by the core-first methodology

Abstract: Eight-arm poly(ethylene oxide) (PEO) stars were prepared by the core-first method with a newly designed octahydroxylated precursor. This compound was readily obtained in two steps from commercially available tert-butylcalix[8]arene. The choice of the proper solvent of polymerization proved crucial to obtain PEO star materials with a narrow distribution of molar masses. For instance, the use of dimethyl sulfoxide (DMSO) resulted in PEO samples of rather large polydispersities (PDI: 1.3–1.5). In this solvent, the calixarene-based precursor was only sparingly soluble, and an attempt to metalate its eight hydroxyl groups produced insoluble alkoxides. In addition, the presence of a side population of low-molar-mass species attributable to linear chains was detected because of the chain transfer of propagating alkoxides to DMSO. Polymerization experiments carried out in tetrahydrofuran (THF) as solvent afforded better control over the molar masses and PDIs. This was related to the better solubility of the octafunctional calixarene-based precursor in THF and to the small tendency of the alkoxides formed to aggregate in that solvent. Under such conditions, all eight hydroxyl functions efficiently initiated the polymerization of ethylene oxide. In this way, well-defined PEO stars (PDI < 1.2) of tunable molar masses incorporating a calixarene-based core could be obtained, as it was supported by the characterization of the samples by size exclusion chromatography, NMR, and viscometry. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1669–1676, 2003

Organolanthanide and organoyttrium hydride chemistry. 6. Direct synthesis and proton NMR spectral analysis of the trimetallic yttrium and yttrium-zirconium tetrahydride complexes, {[(C5H5)2YH]3H}{Li(THF)4} and {[(CH3C5H4)2YH]2[(CH3C5H4)2ZrH]H}

Abstract: Improved syntheses of several trimetallic tetrahydride complexes (tri(diphenyl lanthanon hydride)-lithium tetrahydrofuran) were studied using lithium hydride, methyl hydride, and tetra-butyl lithium reacted with diphenyl yttrium hydride tetrahydrofuran dimer. The reaction with tetra-butyl lithium yields the trimer as above while the reaction with diphenyl yttrium deuteride tetrahydrofuran with tert-butyl lithium forms a perdeuterio trimer indicating that the tert-butyl group does not provide a negative hydrogen ion for the trimer. Proton NMR spectra of some of the compounds are presented with H-H, Y-H, and Y-Y couplng constants derived from computer simulation of the spectra.