- MIL-101-SO3H: A highly efficient Bronsted acid catalyst for heterogeneous alcoholysis of epoxides under ambient conditions
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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.
- Zhou, Yu-Xiao,Chen, Yu-Zhen,Hu, Yingli,Huang, Gang,Yu, Shu-Hong,Jiang, Hai-Long
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Read Online
- A Stable Zn-Based Metal–Organic Framework as an Efficient Catalyst for Carbon Dioxide Cycloaddition and Alcoholysis at Mild Conditions
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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.].
- Luo, Zhiqiang,Wang, Jun,He, Yanqing,Ao, Qiong,Deng, Qiang,Zeng, Zheling,Wang, Hongming,Deng, Shuguang
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- Ship-in-bottle preparation of multi-SO3H functionalized ionic liquid@MIL-100(Fe) for acid-catalyzed ring-opening of epoxides
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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.
- Mortazavi, Saeideh-Sadat,Masteri-Farahani, Majid,Abbasi, Alireza
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- Nanotitania catalyzes the chemoselective hydration and alkoxylation of epoxides
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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.
- Ballesteros–Soberanas, Jordi,Leyva–Pérez, Antonio,Martínez–Castelló, Aarón,Oliver–Meseguer, Judit,Tejeda–Serrano, María
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- On the origin of nitrogen-containing promoters in the cobalt-catalyzed methoxycarbonylation of epoxides
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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.
- He, Jianghua,He, Lin,Li, Zhen,Liu, Jianhua,Liu, Mengli,Wang, Fang,Xia, Chungu,Yun, Dong,Zeng, Bo
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- 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
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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.
- Rahmatpour, Ali,Sajjadinezhad, Seyed Mehrzad
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- 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
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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.
- Rahmatpour, Ali,Zamani, Maryam
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- Tuning Zr12O22 Node Defects as Catalytic Sites in the Metal-Organic Framework hcp UiO-66
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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.
- Chen, Xi,Gates, Bruce C.,Lyu, Yinghui,Qiao, Xu,Wang, Zhengyan,Yang, Dong
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p. 2906 - 2914
(2020/03/23)
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- Method for preparing propylene glycol monomethyl ether (by machine translation)
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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)
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Paragraph 0092-0109
(2020/05/08)
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- Propylene oxidation process
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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.
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Paragraph 0118-0135; 0147
(2020/05/14)
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- A new Br?nsted acid MIL-101(Cr) catalyst by tandem post-functionalization; synthesis and its catalytic application
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A new heterogeneous Br?nsted solid acid catalyst was prepared by tandem post-functionalization of MIL-101(Cr) and utilized for acetic acid esterification and alcoholysis of epoxides under solvent-free conditions. First, MIL-101(Cr) was functionalized with pyrazine to achieve MIL-101(Cr)-Pyz. Afterwards, the nucleophilic reaction of MIL-101(Cr)-Pyz with 1,3-propane sultone and next acidification with diluted sulfuric acid gave MIL-101(Cr)-Pyz-RSO3H Br?nsted solid acid catalyst. Various characterization methods such as Fourier transformation infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), elemental analysis (CHNS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersiveX-ray(EDX) spectroscopy, thermal analysis (TGA/DTA), acid–base titration, and N2 adsorption/desorption analysis were employed to fully characterize the prepared catalyst. The catalyst showed high activity compared to unmodified MIL-101(Cr) in both catalytic acetic acid esterification and alcoholysis of epoxides. It can also be readily isolated from the reaction mixture and reused three times without major decrease in its activity.
- Mortazavi, Saeideh-Sadat,Abbasi, Alireza,Masteri-Farahani, Majid
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- Nano metal oxides as efficient catalysts for selective synthesis of 1-methoxy-2-propanol from methanol and propylene oxide
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Nano metal oxides such as Fe2O3, Fe3O4, CuO, NiO, ZnO and SnO2 were prepared and characterized using XRD, SEM and TEM analysis. These as-prepared metal oxide materials were used as catalysts for the etherification of methanol with propylene oxide (PO). The results showed that α-Fe2O3 exhibited outstanding catalytic performance with 97.7% conversion and 83.0% selectivity to MP-2 at 160 °C for 8 h. Furthermore, the relationship between the catalytic activity or selectivity and surface basicity or energy gap was investigated. This catalyst could be easily recovered and reused due to its heterogeneous catalytic nature.
- Zhang, Jiawei,Cai, Qinghai,Zhao, Jingxiang,Zang, Shuying
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p. 4478 - 4482
(2018/02/07)
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- A heterogenized cobaltate catalyst on a bis-imidazolium-based covalent triazine framework for hydroesterification of epoxides
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An imidazolium-cobaltate-based heterogeneous catalyst exhibits advantages over its homogeneous counterpart in the synthesis of β-hydroxyesters from epoxides. However, leaching of cobaltate from the catalytic support decreases the selectivity and recyclability of the catalyst. To overcome such drawbacks, a bis-imidazolium-based covalent triazine framework (CTF) is employed as a catalytic support for the hydroesterification catalyst to reduce cobaltate leaching by the intramolecular anion stabilization effect of the multi-imidazolium moiety, resulting in an excellent selectivity for the β-hydroxyester and unprecedented recyclability.
- Rajendiran, Senkuttuvan,Gunasekar, Gunniya Hariyanandam,Yoon, Sungho
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p. 12256 - 12262
(2018/07/24)
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- Low-Temperature Preparation of a Mesoporous Silica Superbase by Employing the Multifunctionality of a La2O3 Interlayer
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A simple and effective approach for the preparation of the solid superbasic La2O3–SBA-15-supported KF (KF/La2O3–SBA-15) was developed by a low-temperature strategy. The KF/La2O3–SBA-15 with ordered mesostructure and a high base strength (H?=27.0) was realized at 350 °C in still air, which breaks the traditional method of thermally induced decomposition of basic metal nitrate derived species KNO3 under higher temperatures (>600 °C). The resultant mesoporous basic materials were adopted for the production of 1-methoxy-2-propanol from propylene oxide and methanol. It showed excellent catalytic performance exhibiting 93 % conversion of propylene oxide and 93 % selectivity to 1-methoxy-2-propanol. This performance is better than that over the catalysts without mesoporous silica despite having a higher KF content.
- Liu, Ning,Wu, Zhimin,Li, Meng,Li, Shanshan,Luo, Zhantao,Li, Yongfei,Pan, Langsheng,Liu, Yuejin
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p. 1641 - 1647
(2017/05/15)
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- A novel strategy for constructing mesoporous solid superbase catalysts: Bimetallic Al-La oxides supported on SBA-15 modified with KF
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Bimetallic Al-La oxides were conjointly precoated on SBA-15 prior to the introduction of potassium fluoride to achieve solid superbases at low temperature by a modified wetness impregnation method. This breaks the tradition of decomposition of KNO3 at high temperature and gives rise to a new approach to generating superbasic sites on SBA-15. The physico-chemical characteristics of the prepared KF/Al-La@SBA-15 materials were investigated using FT-IR, XRD, TG-DTG, N2 adsorption-desorption, TEM, SEM-EDS, acid-base titration, Hammett indicators and CO2-TPD measurements. The results demonstrated that the addition of Al species promoted the dispersion behavior of La species inside the channels, and the bimetallic species could synergistically protect the mesoporous structures of SBA-15 against KF corrosion. With increasing Al content, KF/Al-La@SBA-15 exhibited a long-range ordering of the pores with relatively narrow pore size distribution as well as high specific surface area. The research results showed that the KF/Al-La@SBA-15 (0.4) catalyst possessed a total basicity up to 0.79 mmol g-1 and superbasicity with a strength of 26.5. The catalytic activity of the prepared materials was evaluated in the ring-opening reaction of propylene oxide with methanol. Compared with the SBA-15 supported monometallic oxide (Al or La) catalysts, KF/Al-La@SBA-15 (0.4) exhibited the highest catalytic activity for the ring-opening reaction of propylene oxide with methanol. This is associated with the synergistic effects between Al and La species and the high dispersion of active components on the SBA-15 support.
- Liu, Ning,Wu, Zhimin,Li, Meng,Li, Shanshan,Li, Yongfei,Yu, Rongdong,Pan, Langsheng,Liu, Yuejin
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p. 725 - 733
(2017/08/14)
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- Synthesis of propylene glycol ethers from propylene oxide catalyzed by environmentally friendly ionic liquids
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A series of acetate ionic liquids were synthesized using a typical two-step method. The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions. The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions, obtained using ultraviolet-visible spectroscopy, and the relationship between their catalytic activities and basicities was established. The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH. This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used. A possible electrophilic-nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time-of-flight mass spectrometry. In addition, the effects of significant reaction parameters such as concentration of catalyst, molar ratio of alcohol to propylene oxide, reaction temperature, and steric hindrance of the alcohol were investigated in detail.
- Zhao, Cong,Chen, Shengxin,Zhang, Ruirui,Li, Zihang,Liu, Ruixia,Ren, Baozeng,Zhang, Suojiang
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p. 879 - 888
(2017/05/24)
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- Optimized Synthetic Route for Enantioselective Preparation of (S)-Metolachlor from Commercially Available (R)-Propylene Oxide
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An enantioselective preparation of (S)-metolachlor has been accomplished. The synthetic route featured the asymmetric preparation of chiral intermediates and the final (S)-metolachlor from commercially available (R)-propylene oxide and a key Fukuyama's process. The key steps, control points, separation purifications, and the whole process are optimized, and the target compound has been successfully prepared in five steps in 51-55% overall yield with excellent enantioselectivity (99% ee) up to a 30 g scale. By judicious choice of synthetic route and selection of starting materials and intermediates, no column chromatographic methods are needed for the separation and purification of the intermediates and the final products. The same strategy was extended as a general method for a series of pesticides and herbicide analogs of Metalaxyl-M and Dimethenamid-P.
- Yang, Peng,Wang, Xiao,Peng, Lin,Chen, Feng,Tian, Fang,Tang, Chao-Zhe,Wang, Li-Xin
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p. 1682 - 1688
(2017/10/25)
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- Ionic-Liquid-Based Heterogeneous Covalent Triazine Framework Cobalt Catalyst for the Direct Synthesis of Methyl 3-Hydroxybutyrate from Propylene Oxide
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β-Hydroxy esters are considered as potential building blocks for the production of fine chemicals and potential drug molecules in various industries. Developing an efficient and recyclable catalyst for the synthesis of β-hydroxy esters is challenging. Her
- Rajendiran, Senkuttuvan,Park, Kwangho,Lee, Kwangyeol,Yoon, Sungho
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supporting information
p. 7270 - 7277
(2017/06/23)
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- Highly Enantioselective Hydrogenation of Amides via Dynamic Kinetic Resolution Under Low Pressure and Room Temperature
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High-throughput screening and lab-scale optimization were combined to develop the catalytic system trans-RuCl2((S,S)-skewphos)((R,R)-dpen), 2-PrONa, and 2-PrOH. This system hydrogenates functionalized α-phenoxy and related amides at room temperature under 4 atm H2 pressure to give chiral alcohols with up to 99% yield and in greater than 99% enantiomeric excess via dynamic kinetic resolution.
- Rasu, Loorthuraja,John, Jeremy M.,Stephenson, Elanna,Endean, Riley,Kalapugama, Suneth,Clément, Roxanne,Bergens, Steven H.
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supporting information
p. 3065 - 3071
(2017/03/11)
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- Kinetics of propylene epoxidation with hydrogen peroxide catalyzed by extruded titanium silicalite in methanol
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The kinetics of propylene oxidation into propylene oxide in the presence of extruded titanium silicalite was studied. Based on the experimental data, a kinetic model of the process was designed and the activation energies of the target and side reactions, the rate constants, and the adsorption equilibrium constants were determined. The adequacy of the proposed kinetic model was verified on a continuously-operated test bench laboratory unit.
- Sulimov,Danov,Ovcharova,Ovcharov,Flid
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p. 466 - 473
(2016/08/06)
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- One-pot two-step process for direct propylene oxide production catalyzed by bi-functional Pd(Au)@TS-1 materials
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Different bi-functional materials (Pd(Au)@TS-1) based on metallic nanoparticles supported onto active nanocrystalline titanium silicalite (TS-1) zeolites were synthesized, characterized and used as recyclable heterogeneous catalysts for direct propylene oxide production from hydrogen, oxygen and propylene through one-pot two-step consecutive process. These catalysts allowed carrying out the combined reaction where metallic nanoparticles catalyzed the formation of in situ H2O2 that was the necessary intermediate for propylene epoxidation catalyzed by active TS-1 nanocrystalline support. Several variables were considered such as use of supercritical CO2 conditions, modifiable content of metallic species, and presence of additional co-solvents, surface acidity inhibitors and H2O2 stabilizers. Reusability and stability of the bi-functional catalyst was showed through consecutive catalytic cycles.
- Prieto, Alejandro,Palomino, Miguel,Díaz, Urbano,Corma, Avelino
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- Epoxide hydrolysis and alcoholysis reactions over crystalline Mo-V-O oxide
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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.
- Zhang, Xiaochen,Wang, Min,Zhang, Chaofeng,Lu, Jianmin,Wang, Yehong,Wang, Feng
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p. 70842 - 70847
(2016/08/05)
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- Synthetic and natural materials with the brucite-like layers as high active catalyst for synthesis of 1-methoxy-2-propanol from methanol and propylene oxide
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The aim of this study was to investigate the correlation between the basic and catalytic properties of brucite and Mg,Al-layered double hydroxides (Mg,Al-LDHs) in the reaction of propylene oxide with methanol. The basic properties of the solids were investigated by FT-IR spectroscopy using CDCl3 as probe molecule and Hammett acidity titration with n-butylamine and benzoic acid. Both the increase in the activation temperature and the decrease in Al content favored the increase in the basicity of Mg,Al-LDH. The nature of “Mn+[Formula presented]2? Lewis acid-base” pairs was a key factor to control the catalytic behavior of the solids. The length of the M-O bond, the basicity of the oxygen ion and the strength of the metal ion on the surface affected the catalytic activity of the solids and their isomer selectivity in the reaction between methanol and propylene oxide to form 1-methoxy-2-propanol. It was demonstrated that brucite(150) can be applied as catalyst for at least four successive cycles without loss of activity.
- Timofeeva, Maria N.,Kapustin, Aleksey E.,Panchenko, Valentina N.,Butenko, Eleonora O.,Krupskaya, Victoria V.,Gil, Antonio,Vicente, Miguel A.
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- CO2-MEDIATED ETHERIFICATION OF BIO-BASED DIOLS
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A method of etherifying glycols or other diols by employing renewable reagents is disclosed. In particular, the method involves contacting a diol with an alkylating agent in an alcoholic solvent, catalyzed with a catalyst (carbonic acid) generated in situ (from CO2). The mono- and di-ether products can serve as valued precursors to an array of renewable surfactants, dispersants, and lubricants, among others.
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Paragraph 0057; 0058; 0059; 0060
(2016/07/05)
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- Development of a High-Affinity PET Radioligand for Imaging Cannabinoid Subtype 2 Receptor
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Cannabinoid receptors type 2 (CB2) represent a target with increasing importance for neuroimaging due to its upregulation under various pathological conditions. Encouraged by preliminary results obtained with [11C](Z)-N-(3-(2-methoxyethyl)-4,5-dimethylthiazol-2(3H)-ylidene)-2,2,3,3-tetramethyl-cyclopropanecarboxamide ([11C]A-836339, [11C]1) in a mouse model of acute neuroinflammation (induced by lipopolysaccharide, LPS), we designed a library of fluorinated analogues aiming for an [18F]-labeled radiotracer with improved CB2 binding affinity and selectivity. Compound (Z)-N-(3-(4-fluorobutyl)-4,5-dimethylthiazol-2(3H)-ylidene)-2,2,3,3-tetramethyl-cyclopropanecarboxamide (29) was selected as the ligand with the highest CB2 affinity (Ki = 0.39 nM) and selectivity over those of CB1 (factor of 1000). [18F]29 was prepared starting from the bromo precursor (53). Specific binding was shown in vitro, whereas fast metabolism was observed in vivo in CD-1 mice. Animal PET revealed a brain uptake comparable to that of [11C]1. In the LPS-treated mice, a 20-30% higher uptake in brain was found in comparison to that in nontreated mice (n = 3, P 0.05).
- Moldovan, Rare?-Petru,Teodoro, Rodrigo,Gao, Yongjun,Deuther-Conrad, Winnie,Kranz, Mathias,Wang, Yuchuan,Kuwabara, Hiroto,Nakano, Masayoshi,Valentine, Heather,Fischer, Steffen,Pomper, Martin G.,Wong, Dean F.,Dannals, Robert F.,Brust, Peter,Horti, Andrew G.
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p. 7840 - 7855
(2016/10/12)
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- One-step synthesis of dimethyl carbonate from carbon dioxide, propylene oxide and methanol over alkali halides promoted by crown ethers
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Crown ethers (i.e. [2,4]-dibenzo-18-crown-6 (DBC), 18-crown-6, 15-crown-5 and 12-crown-4) show obvious co-catalytic effect for alkali halides catalyzing one-step synthesis of dimethyl carbonate (DMC) from CO2, propylene oxide and methanol. Especially, the DMC yield of KCl catalyst promoted by DBC can increase by more than five times and reach about 40% under mild reaction conditions (i.e., low mole ratio of methanol and epoxieds: 7:3, low initial pressure of CO2: 1.5 MPa, reaction temperature: 140 °C, time: 10 h). The optimized molar ratio of KCl to DBC is 2: 1. Due to the good complexing ability between DBC and K+, KCl and DBC formed an organometallic complex. Actually, DBC can not only promote the reaction rate and equilibrium of cycloaddition and transesterification reactions, but also prevent side reaction. Importantly, DBC can conveniently achieve high recovery ratio and show excellent reusability.
- Li, Lei,Shi, Shikai,Song, Li,Guo, Liping,Wang, Yifei,Ma, Hongxia,Hou, Jie,Wang, Haidong
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p. 231 - 236
(2015/08/03)
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- Epoxidation of propylene over titanosilicate-1 in fixed-bed reactor: Experiments and kinetics
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The epoxidation of propylene with hydrogen peroxide over titanosilicate-1 is studied in a fixed-bed reactor with methanol/water as the solvent. The effects of methanol concentration (40-70 wt %), hydrogen peroxide concentration (5-20 wt %), pressure (1.8-3 MPa) and temperature (35-50 °C) on the reaction are investigated. The results show that the reaction rate decreases with increasing reaction pressure, which is opposite to that reported in the literature. The activation energy of the reaction is 57.4 kJ mol-1 and the orders with respects to hydrogen peroxide and propylene are 0.71 and 0.29, respectively. The intrinsic kinetic modeling results show that an Eley-Rideal (H2O2 adsorbed) kinetic model incorporating the effects of hydrogen peroxide, propylene, methanol and propylene oxide satisfactorily agrees with the experimental results.
- Wang, Lina,Wang, Yaquan,Wu, Guoqiang,Feng, Wenping,Zhang, Teng,Yang, Rumin,Jin, Xing,Shi, Hainan,Wang, Shuhai
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p. 943 - 950
(2014/06/09)
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- Propylene epoxidation with in situ generated H2O2 in supercritical conditions
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Several bi-functional materials based on palladium nanoparticles supported onto nanocrystalline titanium silicalite zeolite (Pd@TS-1) were prepared and used as active and reusable catalysts to direct PO production from hydrogen, oxygen and propylene throu
- Prieto, Alejandro,Palomino, Miguel,Díaz, Urbano,Corma, Avelino
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- Selective decomposition of hydrogen peroxide in the epoxidation effluent of the HPPO process
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This work describes the selective H2O2 decomposition in the exit stream of the epoxidation reactor employed in the Hydrogen Peroxide-Propylene Oxide (HPPO) process. Pd/Al2O3 and Pt/Al2O3 catalysts were tested. The effects of the reaction temperature and the pH of the solution on catalyst performance were investigated. It was found that the Pt catalyst is much more active than its Pd counterpart. An increase in the temperature and the pH of the solution resulted in an increase in the H2O2 decomposition rate; however, a parallel increase of by-products from PO was also observed. Working with a Pt/Al2O3 catalyst under optimized reaction conditions (333 K, pH = 7), hydrogen peroxide can be completely decomposed at reaction times of 120 min with no by-products produced from propylene oxide.
- Blanco-Brieva, Gema,De Frutos-Escrig, M. Pilar,Martín, Hilario,Campos-Martin, Jose M.,Fierro, Jose L.G.
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experimental part
p. 168 - 172
(2012/08/08)
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- PYRAZOLOTHIAZOLE COMPOUND
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A compound represented by the formula (I) or pharmacologically acceptable salt thereof exhibits an excellent CRF receptor antagonism wherein X is a nitrogen atom or CH; R1 is -A11-A12; A11 is a single bond or a C1-6 alkylene group; A12 is a hydrogen atom, a C1-6 alkyl group or a C3-6 cycloalkyl group, etc.; R2 is -A21-A22; A21 is a single bond or a C1-6 alkylene group; A22 is a hydrogen atom, a C1-6 alkyl group, a C3-6 cycloalkyl group, a non-aromatic heterocyclic group, or a heteroaryl group, etc.; R3 is a C 1-6 alkyl group, a C3-6 cycloalkyl group, a C1-6 alkoxy group, a C3-6 cycloalkoxy C1-6 alkyl group, di-C1-6 alkyl amino group, a halogen atom, a cyano group, a formyl group, or a carboxyl group, etc; R4 is a hydrogen atom or a C1-6 alkoxy group; R5 is a halogen atom, a C1-6 alkyl group, or a C1-6 alkoxy group; R6 is a hydrogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylthio group, or a C1-6 alkyl sulfinyl group etc.; and R7 is a C1-6 alkyl group, a C1-6 alkoxy group, or a C1-6 alkylthio group
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Page/Page column 22; 23
(2011/04/25)
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- Synthesis of propylene glycol methyl ether catalyzed by MCM-41
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In this work, we found that MCM-41 prepared using cetyltrimethyl ammonium bromide (CTAB) as the template could be used as a heterogeneous catalyst for the reaction of methanol with propylene oxide to produce propylene glycol methyl ether. 1-Methoxy-2-propanol was the predominant product. The influence of ratio of the reactants, reaction temperature, and time on the yield and selectivity was studied. The as-prepared MCM-41 proved to be an efficient and reusable catalyst, and the separation of the catalyst form the product was very easy.
- Liang, Shuguang,Zhou, Yinxi,Liu, Huizhen,Jiang, Tao,Han, Buxing
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experimental part
p. 891 - 897
(2011/04/23)
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- Tunable synthesis of propylene glycol ether from methanol and propylene oxide under ambient pressure
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A series of basic and acidic ionic liquids, 1-butyl-3-methylimidazolium hydroxide (BMIMOH), 1-acetyl-3-methylimidazolium chloride (AcMIMCl) and AcMIMCl-FeCl3, or analogues of AcMIMCl, namely 1-potassium acetate-3-methylimidazolium chloride (KAcMIMCl), 1-potassium (sodium, ammonium) acetate-3-methylimidazolium hydroxides (KAcMIMOH, NaAcMIMOH and NH 4AcMIMOH), were prepared and used as catalysts for catalytic synthesis of propylene glycol ether via reaction of propylene oxide (PO) with methanol under mild reaction conditions. KAcMIMOH exhibited outstanding catalytic performance with 94.2% of conversion of PO and 99.1% of selectivity to 1-methoxy-2-propanol (MP-2) at 60°C and ambient pressure for 4 h. However, AcMIMCl-FeCl3 showed a good catalysis performance with high selectivity to 2-methoxy-1-propanol (MP-1). The tunable synthesis of MP-2 or MP-1 catalyzed by basic compound KAcMIMOH or acidic ionic liquid AcMIMCl-FeCl3 was realized.
- Bai, Yu,Cai, Qinghai,Wang, Xiaoguang,Lu, Bin
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experimental part
p. 386 - 390
(2011/08/04)
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- An improved one-pot synthesis of dimethyl carbonate from propylene oxide, CO2 and methanol
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The direct synthesis of dimethyl carbonate (DMC) and propylene glycol from propylene oxide, CO2 and methanol has been studied with potassium carbonate as catalyst. This is the first time that K2CO3 which is readily available has been used as a catalyst. It is quite simple and cheap to use. This route may be an effective way of producing DMC on the large-scale. DMC is used in polycarbonate synthesis, polyurethane synthesis, carbonylating reagents, alkylating reagents, polar solvents, octane boosters in gasoline, carbon-particle reducing agents for diesel engines It is a safe and environmentally benign alternative for phosgene in some reactions.
- Fan, Bin,Qu, Bo,Cai, Liang,Chen, Qingchuan,Wen, Yicun,Zhang, Rui
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p. 654 - 656,3
(2020/07/30)
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- Synthesis of cyclic carbonates and dimethyl carbonate using CO2 as a building block catalyzed by MOF-5/KI and MOF-5/KI/K2CO 3
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The synthesis of cyclic carbonates or dimethyl carbonate (DMC) using CO2 as a building block is a very interesting topic. In this work, we found that the metalorganic framework-5 (MOF-5)/KI was an active and a selective catalytic system for the synthesis of cyclic carbonates from CO 2 and epoxides, and MOF-5/KI/K2CO3 was efficient for the preparation of DMC from CO2, propylene, and methanol by a sequential route. The impacts of temperature, pressure, and reaction time length on the reactions were investigated, and the mechanism of the reactions is proposed on the basis of the experimental results.
- Song, Jinliang,Zhang, Binbin,Jiang, Tao,Yang, Guanying,Han, Buxing
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experimental part
p. 21 - 30
(2012/02/14)
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- A systematic study on the activation of simple polyethers by MoCl 5 and WCl6
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MoCl5, 1a, and WCl6, 1b, activate 1,3-dioxolane at room temperature in chlorinated solvents: the compound [MoOCl 3{OC(H)OCH2CH2Cl}]2, 2, has been isolated from MoCl5/dioxolane. The mixed oxo-chloro species WOCl 4, 1c, reacts with 1,3-dioxolane, selectively giving the coordination adduct WOCl4(κ1-C3H6O 2), 3. Dimethoxymethane, CH2(OMe)2, undergoes activation including C-H bond cleavage when reacted with 1a to give the molybdenum complexes [MoOCl3{OC(H)OMe}]2, 4, and Mo 2Cl5(OMe)5, 5. The reactions of 1b with CH 2(OR)2 (R = Me, Et) proceed via O-abstraction with formation of the oxo-derivatives WOCl4[O(R)CH2Cl] (R = Me, 6a; R = Et, 6b) in admixture with equimolar amounts of RCl. The reactions of 1a,b with CMe2(OMe)2 lead to mesityl oxide, MeC(O)CHC(Me)2. A series of simple diethers of general formula ROCH2(CHR′)OR′′ are activated by 1a,b in CDCl 3, usually via cleavage of C-O bonds at high temperature. The complex WCl5(OCH2CH2OMe), 7, has been detected in solution as an intermediate species in the course of the degradation of 1,2-dimethoxyethane (dme) by 1b. The activation of CH(OMe)3 by 1 is limited to C-O bonds and selectively gives methyl chloride and methylformate, which has been found coordinated in WOCl4[OC(H)OMe], 8. The organic fragments produced in the reactions have been detected by GC-MS and NMR analyses, upon hydrolysis of the reaction mixtures. Compounds 2 and 5, which have had their molecular structures ascertained by X-ray diffraction, represent rare examples of crystallographically-characterized dinuclear Mo(v) species containing both halides and oxygen ligands.
- Dolci, Sara,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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experimental part
p. 5367 - 5376
(2010/08/04)
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- Fluorine-modified Mg-Al mixed oxides: A solid base with variable basic sites and tunable basicity
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The fluorine-modified Mg-Al mixed oxides were synthesized by thermal decomposition of the fluorine-containing Mg-Al hydrotalcites, and their physicochemical properties were characterized by ICP, TGA, XRD, FTIR, CO2-TPD and N2 adsorption/desorption techniques. It was found that weak basic sites were gradually transformed into moderate and strong basic sites during thermal decomposition, and thus weak basic sites (OH- groups), moderate basic sites (Mg-O, Mg-F and Al-O pairs) and strong basic sites (coordinatively unsaturated F- and O2- ions) were all produced in the as-prepared samples. Furthermore, the basicity of moderate basic sites could be controlled by the change of fluorine content, which caused the change in the amounts of Mg-F pairs. In the synthesis of propylene glycol methyl ether from methanol and propylene oxide, the base-catalytic performance of the obtained samples was shown to be closely associated with their moderate basic sites.
- Wu, Gongde,Wang, Xiaoli,Wei, Wei,Sun, Yuhan
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scheme or table
p. 107 - 113
(2010/07/16)
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- The tetramethylguanidine-based ionic liquid-catalyzed synthesis of propylene glycol methyl ether
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Tetramethylguanidine-based ionic liquids were used as effective catalysts for the synthesis of propylene glycol methyl ether from methanol and propylene oxide. 1-Methoxy-2-propanol was produced in nearly 90% yield under much milder conditions. The catalyst can be reused at least ten times without any considerable decrease in its activity and selectivity.
- Liang, Shuguang,Liu, Huizhen,Zhou, Yinxi,Jiang, Tao,Han, Buxing
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scheme or table
p. 2534 - 2536
(2011/01/12)
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- Production of propylene glycol monoalkyl ether
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The invention is a process for producing a propylene glycol monoalkyl ether which comprises first reacting propylene oxide and an alcohol in the presence of an alkali or alkaline earth metal alkoxide catalyst to produce an alkoxylation mixture comprising propylene glycol monoalkyl ether; distilling the alkoxylation mixture to produce a first overhead stream comprising propylene oxide and alcohol and a first bottoms stream comprising propylene glycol monoalkyl ether; and then distilling the first bottoms stream to produce purified propylene glycol monoalkyl ether as a second overhead stream. The reaction and/or one or more of the distillation steps occur in the presence of an alkali metal borohydride. The process produces propylene glycol monoalkyl ether with low UV absorbance and reduced carbonyl impurities.
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Page/Page column 3
(2009/07/25)
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- HETEROCYCLIC AMINE CATALYST COMPOSITIONS FOR THE ALKOXYLATION OF ALCOHOLS TO GLYCOL ETHERS
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Glycol ethers are made by a process in which an alcohol, an alkylene oxide and a catalytic amount of an aromatic, heterocyclic amine catalyst are contacted under reactive conditions. Representative catalysis include substituted and unsubsiituted pyridines and imidazoles. The process uses known oxides and alcohols, and produces more mono- and di- adduct products than does a corresponding process using a caustic catalyst. Moreover, the process can be conducted at a lower reaction temperature than a corresponding process using a caustic catalyst without sacrificing oxide conversion rates yet producing fewer carfoony! impurities.
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Page/Page column 8-9, 14
(2009/12/05)
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- Direct epoxidation process using a mixed catalyst system
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Catalyst mixtures useful for the direct epoxidation of olefins are disclosed. The catalyst mixture comprises a titanium or vanadium zeolite and a supported catalyst comprising a noble metal, bismuth, and a carrier. The invention includes a process for producing an epoxide comprising reacting an olefin, hydrogen and oxygen in the presence of the catalyst mixture. The process results in significantly reduced alkane byproduct formed by the hydrogenation of olefin.
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Page/Page column 7
(2009/01/24)
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- Methylammonium-FAU zeolite: Investigation of the basic sites in base catalyzed reactions and its performance
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The basicity of methylammonium-faujasite zeolites (FAU) was evaluated in the Knoevenagel and Claisen-Schmidt condensation reactions and in the alcoholysis of propylene oxide with methanol. The basic character of FAU zeolites (Y zeolite with Si/Al = 2.5 and X zeolite with Si/Al = 1.4) was systematically altered by incorporating cesium and methylammonium cations, which were located in charge compensation sites. In all three reactions, methylammonium-FAU zeolites showed higher specific activity in comparison to cesium-FAU, indicating that these catalysts encompass stronger basic sites. Characterization of the zeolites has shown that ion exchange of sodium by methylammonium cations reduces their micropore volume, however enhances the strength of their basic sites. TPD-CO2 experiments demonstrated that aluminum rich zeolites possess higher basicity due to higher number of sites. Additionally, XPS (O1s) measurements illustrated that when monomethylammonium cation is present in ion exchange sites, structural zeolite oxygen anions have a higher basic character in comparison to cesium-FAU. This unique result opens news perspectives for application of these highly basic and low-cost methylammonium molecular sieves in base-catalyzed reactions such as Knoevenagel, Claisen-Schmidt condensation and nucleophilic cleavage of propylene oxide with methanol.
- Martins, Leandro,Hoelderich, Wolfgang,Cardoso, Dilson
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scheme or table
p. 14 - 24
(2009/02/07)
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- Generation of a solid Bronsted acid site in a chiral framework
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Protonation of chiral porous materials introduces a Bronsted acid centre, the structure of which is unique to the heterogeneous phase requiring pore wall confinement for stable isolation. The Royal Society of Chemistry.
- Ingleson, Michael J.,Barrio, Jorge Perez,Bacsa, John,Dickinson, Calum,Park, Hyunsoo,Rosseinsky, Matthew J.
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p. 1287 - 1289
(2008/12/21)
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- Oxidation process
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A process is disclosed for reacting an olefin, hydrogen, and oxygen in a reactor in the presence of an epoxidation catalyst comprising a transition metal zeolite and a noble metal to produce a product stream comprising an epoxide and an alkane. The alkane is separated and oxidized to at least one oxygenated product.
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Page/Page column 4
(2008/06/13)
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- Process for the epoxidation of olefins
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A process for the epoxidation of olefins which includes i) reacting an olefin with hydrogen peroxide in presence of an epoxidation catalyst and an alcoholic solvent; ii) separating product olefin oxide and unreacted olefin from the reaction product of step i); iii) recovering a stream comprising the alcoholic solvent; and iv) subjecting the recovered stream of step iii) to hydrogenation.
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- Process of separating 1-methoxy-2-propanol and 2-methoxy-1-propanol from aqueous compositions
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A process is disclosed of separating 1-methoxy-2-propanol and 2-methoxy-1-propanol from aqueous compositions, by dewatering of the aqueous composition containing 1-methoxy-2-propanol and 2-methoxy-1-propanol to a concentration of 1-methoxy-2-propanol and 2-methoxy-1-propanol of at least 90 percent by weight in total and isolation of 1-methoxy-2-propanol, 2-methoxy-1-propanol or mixtures thereof by distillation.
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- Process for the epoxidation of olefins
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The present invention relates to a process for the epoxidation of olefins byi) reacting an olefin with hydrogen peroxide in presence of an epoxidation catalyst and an alcoholic solvent;ii) separating product olefin oxide and unreacted olefin from the reaction product of step i);iii) recovering a stream comprising the alcoholic solvent, characterized byiv) subjecting the recovered stream of step iii) to hydrogenation.
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Page/Page column 6-7
(2008/06/13)
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- Process for the epoxidation of olefins
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The invention described herein relates to a process for the catalytic epoxidation of olefins with hydrogen peroxide in a multiphase reaction mixture comprising an liquid aqueous hydrogen peroxide rich phase containing an organic solvent having a solubility in water of at least 10 % by weight at 25xC and an liquid organic olefin rich phase.
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- Process for the epoxidation of olefins
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The invention described herein relates to a process for the catalytic epoxidation of olefins with hydrogen peroxide in a continuous flow reaction system, wherein the reaction mixture is passed through a fixed catalyst bed in down-flow operation mode and the reaction heat is at least partially removed during the course of the reaction.
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- Process for the preparation of epoxides from olefins
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A process for the preparation of epoxides by epoxidation of olefinic compounds with hydrogen peroxide in the presence of a titanium silicalite as a catalyst. A base is introduced into the epoxidation reactor directly or as a mixture with one or more starting substances, under pH control. A pH in the range from 4 to 9.5, preferably a pH of 5 to 9.5, is established and maintained in the reaction mixture or in the starting substance containing the base. Preferably, an aqueous-organic hydrogen peroxide solution with a pH in the range from 8 to 9 is employed and the epoxidation is carried out in a fixed bed reactor.
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- EFFICIENT AND/OR SELECTIVE METHYLATION BY DIAZOMETHANE OF ALCOHOLS, HALO ALCOHOLS, GLYCOLS, AMINO ALCOHOLS AND MERCAPTO ALCOHOLS WITH THE USE OF A PROTON-EXCHANGED X-TYPE ZEOLITE AS AN ACID-BASE BIFUNCTIONAL CATALYST
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Reactions of diazomethane with butanol, allyl alcohol and β- and γ-halo alcohols led to efficient methylation (giving the corresponding methyl ethers) with the use of a proton-excahnged X-type zeolite compared with H2SO4.The reactions with propylene and isobutylene glycols using the zeolite provided regioselective methylation of the primary OH rather than the secondary or tertiary OH, whereas regioselectivity was not observed in the reactions using H2SO4.The reactions with 2-aminoethanol and 2-mercaptoethanol showed high chemoselective S-methylation and N-monomethylation, respectively, in the presence of the zeolite instead of H2SO4.The mechanism for the reactions is proposed to involve acid-base bifunctional catalysis of the zeolite in which the acidic site reacts with diazomethane to form its conjugate acid, and the nucleophilicity of OH and SH groups is enhanced by the interaction of the basic site with the proton of the groups.
- Takeuchi, Hiroshi,Kishioka, Hiroaki,Kitajima, Kunio
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p. 121 - 126
(2007/10/02)
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