1589-47-5Relevant academic research and scientific papers
MIL-101-SO3H: A highly efficient Bronsted acid catalyst for heterogeneous alcoholysis of epoxides under ambient conditions
Zhou, Yu-Xiao,Chen, Yu-Zhen,Hu, Yingli,Huang, Gang,Yu, Shu-Hong,Jiang, Hai-Long
, p. 14976 - 14980 (2014)
For the first time, a ～100% sulfonic acid functionalized metal-organic framework (MOF), MIL-101-SO3H, with giant pores has been prepared by a hydrothermal process followed by a facile postsynthetic HCl treatment strategy. The replete readily accessible Lewis acidic and especially Bronsted acidic sites distributed throughout the framework as well as high stability endow the resultant MOF exceptionally high efficiency and recyclability, which surpass all other MOF-based catalysts, for the ring opening of epoxides with alcohols (especially, methanol) as nucleophiles under ambient conditions.
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 (2020)
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.].
Ship-in-bottle preparation of multi-SO3H functionalized ionic liquid@MIL-100(Fe) for acid-catalyzed ring-opening of epoxides
Mortazavi, Saeideh-Sadat,Masteri-Farahani, Majid,Abbasi, Alireza
, (2021/08/26)
The fact that the homogeneous acid catalysts are usually separated difficulty than heterogeneous catalysts from the reaction media, the opportunity to combine the advantages of both homogeneous and heterogeneous catalytic systems by immobilizing ILs within the pores of a porous solid support host is an alternative method. In this research, a multi-SO3H functionalized ionic liquid derived from hexamethylenetetramine (HMTA) and 1,3-propane sultone was entrapped inside the pores of MIL-100(Fe) through the ship-in-bottle method and utilized for heterogeneous acid-catalyzed ring-opening of epoxides under solvent-free conditions. The physicochemical properties of prepared catalyst were fully elucidated by various methods. FT-IR spectroscopy and elemental analysis approved the successful incorporation of modified groups within the MIL-100(Fe) cavities. The concentration of acid sites was measured via the acid–base titration which exhibited the 0.9?mmol/g H+ in the catalyst structure. Also, thermogravimetric analysis (TGA) profile showed the loosing of modified groups at 300–600°C. Moreover, X-ray diffraction (XRD) analysis showed that the MIL-100(Fe) structure was retained after modification and nitrogen adsorption–desorption analysis (BET method) manifested the decrease in surface area caused by incorporation of ionic liquid. The fabricated catalyst exhibited high catalytic efficiency in methanolysis of styrene oxide (99% conversion in 3?h) under ambient conditions and used without a substantial drop in product yield in further rounds.
Nanotitania catalyzes the chemoselective hydration and alkoxylation of epoxides
Ballesteros–Soberanas, Jordi,Leyva–Pérez, Antonio,Martínez–Castelló, Aarón,Oliver–Meseguer, Judit,Tejeda–Serrano, María
, (2021/10/12)
Glycols and ethoxy– and propoxy–alcohols are fundamental chemicals in industry, with annual productions of millions of tons, still manufactured in many cases with corrosive and unrecoverable catalysts such as KOH, amines and BF3?OEt2. Here we show that commercially available, inexpensive, non–toxic, solid and recyclable nanotitania catalyzes the hydration and alkoxylation of epoxides, with water and primary and secondary alcohols but not with phenols, carboxylic acids and tertiary alcohols. In this way, the chemoselective synthesis of different glycols and 1,4–dioxanones, and the implementation of nanotitania for the production in–flow of glycols and alkoxylated alcohols, has been achieved. Mechanistic studies support the key role of vacancies in the nano–oxide catalyst.
On the origin of nitrogen-containing promoters in the cobalt-catalyzed methoxycarbonylation of epoxides
He, Jianghua,He, Lin,Li, Zhen,Liu, Jianhua,Liu, Mengli,Wang, Fang,Xia, Chungu,Yun, Dong,Zeng, Bo
, (2021/07/26)
The detailed promotion mechanism of nitrogenous compounds in the cobalt-catalyzed methoxycarbonylation of epoxides has not been studied to date. Herein, we present the intrinsic correlation between nitrogenous promoters and activity and selectivity in the alkoxycarbonylation of epoxides by a comprehensive in situ IR spectroscopy and DFT studies. In situ IR spectroscopy confirmed the acid-base neutralization of the nitrogenous promoters and HCo(CO)4, resulting in reduction of the acidity of the catalyst. With the reduced acid-derived activity for formation of ethers as by-products, the selectivity of desired esters was increased. DFT calculations showed that a nitrogenous base could facilitate the methanolysis of cobalt-acyl species with lowered activation energy, which is considered to be the rate-determining step in the catalytic cycle. As a result, the reaction activity towards carbonylation was also improved by nitrogenous promoters. The present studies will provide new insights to the long-term confusing problems in epoxides carbonylation.
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.
MBA-cross-linked poly(N-vinyl-2-pyrrolidone)/ferric chloride macromolecular coordination complex as a novel and recyclable Lewis acid catalyst: Synthesis, characterization, and performance toward for regioselective ring-opening alcoholysis of epoxides
Rahmatpour, Ali,Zamani, Maryam
, (2021/09/30)
A novel macromolecular-metal coordination complex, MBA-cross-linked PNVP/FeCl3 material was fabricated by immobilization of water intolerant ferric chloride onto the porous cross-linked poly(N-vinyl-2-pyrrolidone) carrier beads as a macromolecular ligand or carrier which was prepared by suspension free-radical copolymerization of N-vinyl-2-pyrrolidone (NVP) and N,N′-methylene bis-acrylamide (MBA) as a crosslinking agent in water. The obtained PNVP/FeCl3 was characterized by UV/vis and FT-IR spectroscopies, TGA, FE-SEM, EDX, and ICP techniques. This heterogenized version of ferric chloride is a convenient and safe alternative to highly water intolerant ferric chloride. The catalytic performance of (PNVP/FeCl3) as an efficient and recyclable polymeric Lewis acid catalyst was appropriately probed in the regio-and stereoselective nucleophilic ring opening of various epoxides with various alcohols in excellent yields with TOF up to 182.48 h?1 without generating any waste. The activity data indicate that this heterogeneous catalyst is very active and could be easily recovered, and reused at least six times without appreciable loss of activity indicating its stability under experimental conditions.
Tuning Zr12O22 Node Defects as Catalytic Sites in the Metal-Organic Framework hcp UiO-66
Chen, Xi,Gates, Bruce C.,Lyu, Yinghui,Qiao, Xu,Wang, Zhengyan,Yang, Dong
, p. 2906 - 2914 (2020/03/23)
Defects in metal-organic frameworks (MOFs) play important roles in MOF reactivity and catalysis. Now, we report evidence of the reactivity and the quantitative characterization of the missing linker defects on the Zr12O22 nodes in the MOF hcp UiO-66 (these are paired Zr6O8 nodes bridged by OH groups) and those on the Zr6O8 nodes of the MOF UiO-66. The defect sites catalyze the ring-opening reactions of epoxides with alcohols, and new sites formed by removal of bridging OH groups on the Zr12O22 nodes also participate in the catalysis. The hcp UiO-66 was synthesized from UiO-66 and from molecular precursors, and, under various synthesis conditions, the nodes incorporated acetate ligands, where linkers were missing, and the number of these ligands was controlled by the synthesis conditions. These ligands are inhibitors of the catalytic reactions, and their removal by reaction with, for example, methanol (to form, for example, methyl acetate) preceded catalysis on the defect sites. The former MOF incorporated more defect sites than the latter, correspondingly being a more active catalyst. The defect sites on the Zr12O22 nodes are 2-6 times more active per site than those on the isolated Zr6O8 nodes, with the node-bridging OH groups increasing the catalytic activity of the neighboring node defect sites because new sites are formed by their removal. The results help point the way to the design and control of catalytic sites on metal oxide-like MOF nodes by tuning of the number and reactivity of the defect sites.
Method for preparing propylene glycol monomethyl ether (by machine translation)
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Paragraph 0092-0109, (2020/05/08)
The method comprises, under the alcoholysis reaction condition, contacting: the propylene oxide, methanol and the catalyst in the reaction zone of the moving bed reactor, the selectivity, of, methoxy - 1 1-propanol. in the fixed bed reactor can be effectively avoided, and the service life, of the catalyst can be prolonged simultaneously. 2 - The catalyst containing titanium silicoaluminophosphate molecular sieve (MME - 2) can effectively avoid the catalyst bed temperature scheduling problem . The catalyst containing the propylene glycol monomethyl ether can be, regenerated . (by machine translation)
Propylene oxidation process
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Paragraph 0118-0135; 0147, (2020/05/14)
The invention relates to a propylene oxidation method, which comprises: S1, carrying out a first reaction on propylene, an oxidizing agent and methanol in the presence of a first catalyst to obtain afirst reaction mixture, wherein the first catalyst contains a titanium silicalite molecular sieve; S2, mixing the first reaction mixture with a second catalyst to carry out a second reaction, whereinthe second catalyst contains a titanium-silicon-aluminum molecular sieve; the molar ratio of the propylene to the oxidizing agent to the methanol is 1: (0.1-10): (10.5-100); and the ratio of the reaction time of the first reaction to the reaction time of the second reaction is 1: (0.1-50). The method can be used for producing propylene glycol monomethyl ether under mild conditions.
