19089-47-5Relevant 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.
A Stable Zn-Based Metal–Organic Framework as an Efficient Catalyst for Carbon Dioxide Cycloaddition and Alcoholysis at Mild Conditions
Luo, Zhiqiang,Wang, Jun,He, Yanqing,Ao, Qiong,Deng, Qiang,Zeng, Zheling,Wang, Hongming,Deng, Shuguang
, p. 1408 - 1417 (2019/12/09)
Abstract: Developing highly efficient heterogeneous catalysts for cycloaddition of CO2 and epoxides to produce cyclic carbonates is promising but challenging. In this work, a novel three-dimensional metal organic framework (MOF) with cylinder pore systems and unsaturated Zn sites has been demonstrated as potent candidate in CO2 fixation at mild and solvent-free conditions. The Zn(atz)(bdc)0.5, where atz = aminotriazole and H2bdc = terephthalic, exhibits microporous nature that can regulate the catalytic interaction of active centers and substrates. The structure stability has been systematically investigated and proven to be sufficient for practical application. Furthermore, the cooperative effects of porosity, CO2 binding affinity, activation centers, and synergism with co-catalyst have been deeply investigated. Moreover, high propylene epoxide conversion (97%) and selectivity (> 99%) have been achieved at mild conditions (60?°C and 1?MPa) with excellent cycle stability. Owing to the well-defined pore system, an obvious substrates selectivity has been clearly observed. A possible catalytic mechanism has been proposed and verified by DFT calculations. Furthermore, the prepared Zn-MOF can also be used as an efficient heterogeneous catalyst for the reaction of epoxides with alcohols to produce β-alkoxy alcohol. Graphic Abstract: [Figure not available: see fulltext.].
Epoxide hydrolysis and alcoholysis reactions over crystalline Mo-V-O oxide
Zhang, Xiaochen,Wang, Min,Zhang, Chaofeng,Lu, Jianmin,Wang, Yehong,Wang, Feng
, p. 70842 - 70847 (2016/08/05)
Crystalline Mo-V-O oxides have been used as a catalyst for the hydrolysis and alcoholysis of propylene oxide to diols and ethers, respectively. Relationships between the active crystal facet, the acidity of Mo-V-O catalysts and the activity have been established. Our results indicate that the a-b plane is the active facet for the hydrolysis reaction.
