2979-26-2Relevant articles and documents
Cross-linked poly(N-vinylpyrrolidone)-titanium tetrachloride complex: A novel stable solid TiCl4 equivalent as a recyclable polymeric Lewis acid catalyst for regioselective ring-opening alcoholysis of epoxides
Rahmatpour, Ali,Sajjadinezhad, Seyed Mehrzad
, (2021/08/09)
Cross-linked poly(N-vinylpyrrolidone) resin beads were prepared as macromolecular ligand precursors by suspension copolymerization of N-vinyl-2-pyrrolidone and N,N′-methylenebisacrylamide (MBA) as a crosslinking agent in water. Subsequently, the resulting polymer carrier precursor was readily combined with titanium tetrachloride to form a stable polymeric coordination complex (PNVP/TiCl4), and this novel stable TiCl4 equivalent evaluated as a heterogeneous and reusable solid Lewis acid catalyst for the regio-and stereoselective nucleophilic ring opening of various epoxides with various alcohols to prepare β-alkoxy alcohols in excellent yields without generating any waste. The MBA-cross-linked PNVP and resultant catalyst were characterized by Fourier transform infrared spectroscopy (FT–IR), field-emission scanning electron microscope (FE–SEM), energy dispersive X-ray (EDX), inductively coupled plasma (ICP), and thermogravimetric analysis (TGA) techniques. Moreover, the catalyst is very stable, easily separated, and reused at least five times without significant loss of activity. In terms of scope, yields, the amount of catalyst used, and reaction time, the PNVP-TiCl4 complex catalyst is an improvement over previously reported heterogeneous catalysts for ring opening of epoxides methods. Further, the experimental outcome revealed that using the copolymer beads as carriers with a high percentage of crosslinking and the high mesh size leads had an adverse effect on the reaction rate.
Thermodynamic analysis of liquid-phase dehydrogenation of o-ethoxycyclohexanol to guaethol
Liu, Yanlong,Zhang, Yadong,Feng, Junbo,Shi, Xiancai
, p. 637 - 644 (2020/07/28)
The standard molar enthalpies of formation, standard molar entropies and molar heat capacities of o-ethoxycyclohexanol and guaethol in liquid phase are calculated based on the Benson group contribution method. The function formulas of reaction enthalpy ch
The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Br?nsted acid catalysts
Belokon, Yuri N.,Dmitrienko, Artem O.,Gak, Alexander S.,Gerasimov, Igor S.,Kuznetsova, Svetlana A.,Larionov, Vladimir A.,Li, Han,Medvedev, Michael G.,Nelyubina, Yulia V.,North, Michael,Saghyan, Ashot S.,Smol'yakov, Alexander F.,Zhereb, Vladimir P.
supporting information, p. 1124 - 1134 (2020/07/10)
The acid–base neutralization reaction of commercially available disodium 2,6-naphthalenedisulfonate (NDS, 2 equivalents) and the tetrahydrochloride salt of tetrakis(4-aminophenyl)methane (TAPM, 1 equivalent) in water gave a novel three-dimensional charge-assisted hydrogen-bonded framework (CAHOF, F-1). The framework F-1 was characterized by X-ray diffraction, TGA, elemental analysis, and 1H NMR spectroscopy. The framework was supported by hydrogen bonds between the sulfonate anions and the ammonium cations of NDS and protonated TAPM moieties, respectively. The CAHOF material functioned as a new type of catalytically active Br?nsted acid in a series of reactions, including the ring opening of epoxides by water and alcohols. A Diels–Alder reaction between cyclopentadiene and methyl vinyl ketone was also catalyzed by F-1 in heptane. Depending on the polarity of the solvent mixture, the CAHOF F-1 could function as a purely heterogeneous catalyst or partly dissociate, providing some dissolved F-1 as the real catalyst. In all cases, the catalyst could easily be recovered and recycled.
