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.

Tetrameric Cubic Structures of Two Solvated Lithium Enolates

Abstract: The structures of the crystalline lithium enolates derived from 3, 3-dimethyl-2-butanone and from cyclopentanone have been determined by X-ray analysis. Both structures are tetrameric aggregates based on a Li4O4-cube, each Li+-ion being additionally bonded to the O-atom of a tetrahydrofuran solvent molecule.

Bis(imino)pyridine Iron(II) Alkyl Cations for Olefin Polymerization

Abstract: Treatment of the five-coordinate ferrous dialkyl complex, (iPrPDI)Fe(CH2SiMe3)2 (iPrPDI = ((2,6-CHMe2)2C6H3NCMe)2C5H3N), with [PhMe2NH][BPh4] in the presence of diethyl ether or tetrahydrofuran furnished the corresponding alkyl cations, where the donor ligand is coordinated in the basal plane of a distorted square pyramidal iron(II) alkyl cation. Performing the same reaction with the neutral Lewis acid, B(C6F5)3, induced methide abstraction from a silicon atom followed by rearrangement to afford the base free ferrous alkyl cation, [(iPrPDI)Fe(CH2SiMe2CH2SiMe3)][MeB(C6F5)3]. This complex is active for the polymerization of ethylene and yields polymers that are of higher molecular weight and narrower polydispersity than traditional methylalumoxane-activated catalysts.

Preparation of a New Type of Phosphazene High Polymers Containing 2,2‘-Dioxybiphenyl Groups

Abstract: The direct reaction of [NPCl2]n with the difunctional reagent 2,2‘-dihydroxybiphenyl (HOC6H4C6H4OH) and K2CO3 in tetrahydrofuran gave soluble linear phosphazene high polymers instead of the expected cross-linked products. The reaction of [N3P3Cl6] with 1, 2, or 3 equiv of HOC6H4C6H4OH and K2CO3 in acetone gave the known spiro derivatives [N3P3Cl4(O2C12H8)], [N3P3Cl2(O2C12H8)2], and [N3P3(O2C12H8)3] without formation of bridging products, and the dichloro derivative reacted directly with para-substituted phenols HOC6H4R and K2CO3 in acetone to give the new compounds [N3P3(OC6H4R)2(O2C12H8)2] (R = Br, COC6H5, or OCH3), without signs of replacement of the bis(aryloxy) substituents. In an analogous manner, poly(dichlorophosphazene) [NPCl2]n reacted with HOC6H4C6H4OH and K2CO3 in THF without significant cross-linking to give, depending on the mole ratio, the soluble polymer [NP(O2C12H8)]n (Mw = 450 000, Tg = 160 °C) or the partially substituted polymers {[NP(O2C12H8)]0.35[NPCl2]0.65}n. The latter were subseque...

Phase relations and binary clathrate hydrate formation in the system H2-THF-H2O.

Abstract: Experimentally determined equilibrium phase relations are reported for the system H 2 -THF-H 2 O as a function of aqueous tetrahydrofuran (THF) concentration from 260 to 290 K at pressures up to 45 MPa. Data are consistent with the formation of cubic structure-II (CS-II) binary H 2 -THF clathrate hydrates with a stoichiometric THF-to-water ratio of 1:17, which can incorporate modest volumes of molecular hydrogen at elevated pressures. Direct compositional analyses of the clathrate phase, at both low (0.20 mol %) and stoichiometric (5.56 mol %) initial THF aqueous concentrations, are consistent with observed phase behavior, suggesting full occupancy of large hexakaidecahedral (5 12 6 4 ) clathrate cavities by THF, coupled with largely complete (80-90%) filling of small dodecahedral (5 12 ) cages by single H 2 molecules at pressures of >30 MPa, giving a clathrate formula of (H 2 )≤2·THF·17H 2 O. Results should help to resolve the current controversy over binary H 2 -THF hydrate hydrogen contents; data confirm recent reports that suggest a maximum of ∼1 mass % H 2 , this contradicting values of up to 4 mass % previously claimed for comparable conditions.