A new catalyst for direct synthesis of dimethyl ether from synthesis gas

A new catalyst has been prepared by coprecipitation sedimentation method developed in our laboratory. It exhibits excellent catalytic activity, selectivity and stability for conversion of synthesis gas to dimethyl ether: conversion of CO 92%, selectivity of dimethyl ether 98%. Catalytic properties of the catalyst show no evident change after being used for 100 h.     

An efficient catalyst system for diaryl ether synthesis from aryl chlorides

The combination of 2-phosphino-substituted N-arylpyrroles or related indoles (cataCXium^®P) and Pd(OAc)₂ allows for efficient cross-coupling reactions of aryl chlorides and phenols to give diaryl ethers. A variety of aryl and heteroaryl chlorides can be coupled with substituted phenols showing unprecedented catalyst turnover numbers.     

Bifunctional copper catalysts for an atom efficient ether synthesis

A direct etherification of aromatic ketones and aliphatic alcohols into the corresponding asymmetrical ethers by the use of a bifunctional heterogeneous copper catalyst is described. The reaction protocol reveals to be versatile and convenient respect to the traditional ether synthesis for both environmental and practical concerns.     

Immobilized copper catalyst for atom transfer radical addition and polymerization

A novel multidentate amine grafted on silica gel and magnetic microsphere was prepared. Its chemical structure was confirmed by C¹³ NMR, XPS and FTIR, and the nitrogen content was determined by elemental analysis. It was also used as a ligand for CuCl and successfully catalyzed the atom transfer radical addition of both carbon tetrachloride (CCl₄) to methyl methacrylate and methyl trichloroacetate to styrene, repeatedly. The conversion and purity of the product were determined through gas chromatography and ¹H NMR, respectively. The immobilized copper catalyst complex was also used in atom transfer radical polymerization of styrene initiated by 1,1,1,3‐tetrachloro‐3‐phenylpropane and methyl methacrylate initiated by methyl 2‐methyl‐2,4,4,4‐tetrachlorobutyrate, respectively. Although the polymerization took place successfully, it did not proceed in a controlled fashion. Copyright © 2010 John Wiley & Sons, Ltd.     

Copper catalyst activation driven by photoinduced electron transfer: a prototype photolatent click catalyst

PET cat. While the copper(II) tren ketoprofenate precatalyst 1 (see picture) is inactive at room temperature in methanol, it is quantitatively and rapidly reduced to its cuprous state upon light irradiation to provide a highly reactive click catalyst. By simply introducing air into the reaction medium the catalysis can be switched off and then switched on again by bubbling argon followed by irradiation.     

A novel hydrophobic copper complex supported on γ‐Fe2O3 as a magnetically heterogeneous catalyst for one‐pot three‐component synthesis of α‐aminophosphonates

A novel hydrophobic copper complex supported on γ‐Fe₂O₃ is synthesized and characterized by different methods such as FT‐IR, XRD, TEM, SEM, TGA, VSM, ICP and CHN analysis. It was used as a magnetically recyclable heterogeneous catalyst for the efficient synthesis of α‐aminophosphonates via a one‐pot three‐component reaction under solvent‐free conditions. The present catalytic system worked extremely well for the synthesis of α‐aminophosphonates even up to five subsequent trails without significant loss of its catalytic activity or copper leaching. The TEM image and FT‐IR spectrum of the catalyst after five times recovery showed that the structure of the catalyst was stable under the reaction conditions with no change being observed. The strong magnetic properties of the reused catalyst were revealed by complete and easy attraction using an external magnet and also by VSM curve. This work represents the first and unique example of a hydrophobic copper complex for catalysis in water generating reactions.     

合成气一步法制备二甲醚核壳结构催化剂的制备及其反应性能

以生物质(葡萄糖、蔗糖、淀粉)为模板剂,通过水热合成法制备具有核壳结构的CuO-ZnO-Al₂O₃@Al₂O₃复合催化剂,该催化剂以甲醇合成催化剂CuO-ZnO-Al₂O₃为核,甲醇脱水催化剂Al₂O₃为壳.SEM-EDS对催化剂核壳结构的表征发现,通过改变水热合成温度和合成时间可以调变催化剂中Al₂O₃壳层的厚度.将该复合催化剂用于合成气直接制备二甲醚的反应,在空速1 500 mL/(h·g_cat)、温度260 ℃、压力5.0 MPa的条件下,CO转化率和二甲醚选择性分别达到35.2%和61.1%.     

A new copper complex on graphene oxide: A heterogeneous catalyst for N-arylation and C-H activation

Graphene oxide supported Cu (II) ligand complex (GO@AP/L-Cu) has been synthesized and characterized by FT-IR, Raman, PXRD, UV–Visible, TGA, XPS, FESEM, TEM, EDAX, Elemental mapping, BET, CHNS and AAS analysis. The complex has been found to be efficient and reusable heterogeneous catalyst for the N-arylation and C-H activation reactions, both the catalytic reactions were found to be simple, cleaner and give high yields (~ 90%) of product. The catalyst can be easily filtered out from the reaction mixture and reused up to four times without significant loss of catalytic activity. The reported method is economical and novel in the sense that aqueous medium was used for both the reactions and for the stability of the catalyst. All isolated organic products were fully characterized on the basis of their physical and spectral data.     

Zinc oxide nanoparticles:A highly efficient and readily recyclable catalyst for the synthesis of xanthenes

A novel and efficient route for the synthesis of 1,8-dioxooctahydroxanthenes and 14-aryl-14H-dibenzo[a,j]xanthenes is described through one-pot multi-component reaction of dimedone and 2-naphthol with various aryl aldehydes using ZnO nanoparticles under solvent-free conditions.This method provides a novel and improved pathway for the synthesis of xanthenes in the terms of excellent yields,short reaction times,reusability and low catalyst loading.     

Magnesium perchlorate — A new catalyst for the synthesis of difurylarylmethanes

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1277–1278, September, 1991.     

Hydrogenation of nitroarenes on silica-supported copper catalyst

A 9% Cu/SiO₂ catalyst prepared by the deposition– precipitation technique was active in the hydrogenation of substituted nitrobenzenes at 170 °C and 13 atm H₂ in a batch reactor. Nitro groups were selectively reduced to NH₂ groups except for the case of 5-bromo-1,3-dinitrobenzene. The selectivity of the overall process is somewhat suppressed by inevitable formation of azo compounds and traces of tars due to the reactions of the obtained amines with nitroso intermediates.     

A dual catalyst system provides the shortest pathway for L-menthol synthesis

We have demonstrated that a combination of enantiopure 2-diarylmethylpyrrolidines and heterogeneous Pd/BaSO(4) is an efficient catalytic system for the asymmetric hydrogenation of citral, specifically, a mixture of E-citral and Z-citral in any ratio, and that citronellal is obtained with high enantioselectivity. This dual catalyst system provides a new and more economical route to L-menthol.     

Hydrocarbon production rates in Fischer-Tropsch synthesis over a Fe/Cu/La/Si catalyst

The detailed kinetics of Fischer-Tropsch synthesis over an industrial Fe/Cu/La/Si catalyst was studied in a continuous spinning basket reactor under the conditions relevant to industrial operations. Reaction rate equations were derived on the basis of Langmuir-Hinshelwood-Hougen-Watson type models for Fischer-Tropsch synthesis based on possible reactions sets originated from the carbide, enolic and combined enol/carbide mechanisms. Kinetic model candidates were evaluated by the global optimization of kinetic parameters, which were realized by first minimization of multi-response objective functions with conventional Levenberg-Marquardt method. It was found that an enolic mechanism based model could produce a good fit of the experimental data. The activation energy for paraffin formation is 95 kJ·mol^?1 which is smaller than that for olefin formation (121 kJ·mol^?1).     

Stannous-acetylacetonate： A new catalyst for poly（trimethylene terephthalate） synthesis

Stannous-acetylacetonate was prepared efficiently and characterized by 1H NMR and FT-IR. Its catalytic activity for poly(trimethylene terephthalate) (PTT) synthesis was investigated. By this catalyst, the degree of esterification of pure terephthalic acid was up to 91.7% after reaction at 260°C for 2 h, while the intrinsic viscosity and content of ter- minal carboxyl groups of the corresponding PTT polymerized at 260°C, 60 Pa for 2 h was 0.8816 dL/g and 17 mol/t, respectively. Stannous-acetylacetonate was more active and promising than tetrabutyl titanate and stannous octoate for PTT synthesis.     

浆态床合成二甲醚复合催化剂失活原因探索

在反应温度260 ℃、压力5.0 MPa的条件下,对浆态床反应器中二甲醚合成复合催化剂的失活规律进行了研究.结果表明,Cu基催化剂失活较快是导致浆态床二甲醚合成催化剂不稳定的主要原因.通过分析Cu基催化剂在浆态床反应器和固定床反应器中的活性变化规律,发现在浆态床反应器中不能及时导出反应体系的H2O对催化剂的毒副作用导致了浆态床Cu基催化剂快速失活.对失活催化剂进行的TPR、XRD和SEM-EDS表征结果可以看出,Cu粒子的长大和积炭是Cu基催化剂失活的重要原因,与已有文献报道不同的是并未发现明显的Cu元素流失.     

A new method for the synthesis of cinnamonitriles by catalytic olefination

Catalytic olefination of hydrazones of aromatic aldehydes with dibromoacetonitrile affords cinnamonitriles.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 247–249, January, 2005.