Topic
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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TL;DR: In this paper, the copolymerization of divinylbenzene (DVB) and ethylstyrene (EtSt) was carried out at 70 and 80 °C in benzene with dimethyl 2,2-azobisisobisobyrate (MAIB) at high concentrations as initiator in the presence of methyl benzyloxyiminoacetate (MBOIA), a glyoxylic oxime ether, as a retarder.
Abstract: The copolymerization of divinylbenzene (DVB) and ethylstyrene (EtSt) was carried out at 70 and 80 °C in benzene with dimethyl 2,2-azobisisobutyrate (MAIB) at high concentrations as initiator in the presence of methyl benzyloxyiminoacetate (MBOIA), a glyoxylic oxime ether, as a retarder. The copolymerization system of DVB (0.25 mol/L), EtSt (0.25 mol/L), MBOIA (0.5 mol/L), and MAIB (0.5 mol/L) gave benzene-soluble copolymers despite a considerably high concentration of DVB as an excellent crosslinker. The yield and molecular weight of the resulting copolymers increased with time both at 70 and 80 °C and then leveled off because of initiator consumption. The homogeneous polymerization system involved electron spin resonance (ESR), observable nitrogen-centered polymer radicals (MBOIA.) under the actual polymerization conditions. The MBOIA. concentration increased with time despite a homogeneous polymerization system, suggesting the formation of rigid hyperbranched polymers. A benzene solution of isolated copolymer also showed an ESR signal. The copolymer was soluble in acetone, toluene, chloroform, ethyl acetate, tetrahydrofuran, and N,N-dimethylformamide but insoluble in n-hexane, methanol, and dimethyl sulfoxide. MAIB fragments as high as 30-40 mol % were incorporated into the copolymers through initiation and primary radical termination, on the basis of which this polymerization was named the initiator-fragment incorporation radical polymerization. MBOIA (13-16 mol%) was also incorporated into the copolymers through an opening of the C=N bond. The intrinsic viscosity of the copolymers was very low (0.08 dL/g), and the reduced viscosity was almost independent of the polymer concentration, supporting a hyperbranched structure of them. Gel permeation chromatography and multi-angle laser light scattering and transmission electron microscopy revealed that the copolymer was formed as a hyperbranched nanoparticle. The thermal behavior of the copolymer was examined by dynamic thermogravimetry and differential scanning calorimetry.
49 citations
TL;DR: In this article, the reaction of Na 2 [nido-7,8-Me 2 -7, 8-C 2 B 9 H 9 ] with [Ni 2 (μ-Br) 2 (η 3 -C 3 H 2 ) 2 ] or [Pt 2 (mbr) 2 η 3 c 3 H 5 ] + salts has been studied.
Abstract: Reaction of Na 2 [nido-7,8-Me 2 -7,8-C 2 B 9 H 9 ] with [Ni 2 (μ-Br) 2 (η 3 -C 3 H 2 ) 2 ] or [Pt 2 (μ-Br) 2 (η 3 -C 3 H 5 ) 2 ] - in thf (tetrahydrofuran) gives the anionic species [M(η 3 -C 3 H 5 )(η 5 -7,8-Me 2 -7,8-C 2 B 9 H 9 )] - (M=Ni or Pt) which have been isolated as their [NEt 4 ] 4 and [N(PPh 3 ) 2 ] + salts
49 citations
TL;DR: Prenyllithium and cis-crotyllithium react with carbonyl compounds to give the branched alcoholates with moderate to high selectivity, unless access to the carbonyls group is strongly hindered as mentioned in this paper.
Abstract: Prenyllithium (3-methylbut-2-enyl-lithium) (1) and cis-crotyllithium (Z-but-2-enyl-lithium) (2) in tetrahydrofuran solution, prepared according to the method of Eisch & Jacobs, react with carbonyl compounds to give the branched alcoholates with moderate to high selectivity, unless access to the carbonyl group is strongly hindered (see the Table). Adamantanethione (12) reacts with 1 to give the unbranched thiolate.
49 citations
TL;DR: In this article, a new diamine monomer containing pyridine unit, 2,6-bis(4-aminophenoxy-4-benzoyl)pyridine (BABP), was synthesized successfully.
49 citations
49 citations