Immobilization of Ru — TsDPEN catalyst on functionalized MCM — 41

A Ru — TsDPEN (RuCl[(1S,2S)-N-p-tosyl-1,2-diphenylethylendiamine]p-cymene) catalyst of the Noyori type was immobilized in the channels of MCM — 41 molecular sieve functionalized by (3 — aminopropyl)triethoxysilane (APTES). The resulting compound was tested as a catalyst for the hydrogenation of 1-methyl-3,4-dihydroisoquinoline (MIQ) under laboratory conditions using an azeotropic mixture of formic acid and triethylamine (5:2) as the source of hydrogen and compared to the results acquired in the corresponding system.     

Cobalt Element Effect of Ternary Mesoporous Cerium Lanthanum Solid Solution for the Catalytic Conversion of Methanol and CO2 into Dimethyl Carbonate

A citric acid ligand assisted self-assembly method is used for the synthesis of ternary mesoporous cerium lanthanum solid solution doped with metal elements (Co, Zr, Mg). Their textural property was characterized by X-ray diffraction, transmission electron microscopy, N₂ adsorption-desorption, X-ray photoelectron spectroscopy and TPD techniques, and so on. The results of catalytic testing for synthesis of dimethyl carbonate (DMC) from CH₃OH and CO₂ indicated that the DMC yield reached 316 mmol/g on Ce-La-Co solid solution when the reaction temperature was 413 K and the reaction pressure was 8.0 MPa. It was found that Co had synergistic effect with La and Ce, doping of Co on the mesoporous Ce-La solid solution was helpful to increase the surface area of the catalyst, promote CO₂ adsorption and activation, and improve the redox performance of solid solution catalyst. The conversion of Co²⁺ to Co³⁺ resulted in the continuous redox cycle between Ce⁴⁺ and Ce³⁺, and the oxygen vacancy content of the catalyst was increased. Studies have shown that the catalytic performance of Ce-La-Co solid solution is positively correlated with oxygen vacancy content. On this basis, the reaction mechanism of DMC synthesis from CO₂ and CH₃OH on the catalyst was speculated.     

Reductive carbonylation of nitrobenzene to phenylurethane catalyzed by Ru(III)-schiff base complexes

Ruthenium complexes containing Schiff bases with N₂O₂, N₄ and N₅ donor groups with the general formula [Ru^III(X)Cl_{1 or 2}], where X = Schiff base such as bis(salicylaldehyde)-o-phenylenediimine (saloph), bis(salicylaldehyde)ethylenediimine (salen), bis(picolaldehyde)ethylenediimine (picen), bis(picolaldehyde)-o-phenylenediimine (pic-opd), bis(picolaldehyde)diethylenetriimine (pic-dien), were tested for their catalytic activity towards the reductive carbonylation of nitrobenzene in ethanol to give phenylurethane. The five Ru(III) complexes tested towards reductive carbonylation showed different catalytic activities in the range 160 – 200 °C and CO partial pressure of 15 atm.Among the complexes tested, [Ru(saloph)Cl₂] showed the highest catalytic activity with a turnover rate greater than 80 mol product per mol catalyst per hour at 160 °C and 15 atm CO. [Ru(pic-en)Cl₂]Cl and [Ru(picopd)Cl₂]Cl complexes with N₄ donor systems were found to be less active towards carbonylation of nitrobenzene, as indicated by their turnover rates of 20 and 15 mol product per mol catalyst per hour, respectively, at 200 °C and 15 atm CO. The complex [Ru(pic-dien)Cl]Cl₂N₅ donor system was completely inactive even at 200 °C and 15 atm CO, and no conversion of nitrobenzene was seen even after 12 h contact time.     

Selective hydrogenation of nitrobenzene top-Aminophenol by the polymer-supported palladium-based mono- and bimetallic catalyst

In acidic reaction medium, polymer-supported monometallic palladium catalyst, PVP-PdCl₂ [(PVP=poly(N-vinyl-pyrrolidone)], is used to catalyze the hydrogenation of nitrobenzene top-aminophenol and aniline. The addition of a second transition metal compound or a very small amount of 2-mercaptopyrimidine gives rise to an increase in the selectivity forp-aminophenol.     

Cationic oligomerization of styrene by solid acids. I. Catalysis by poly(styrenesulfonic acid) resin

Cationic oligomerizations of styrene by a solid acid [poly(styrenesulfonic acid) resin, Amberlyst 15] and by the corresponding soluble catalyst (p-toluenesulfonic acid) were compared with respect to their reactivity and the molecular weight distribution of products. The feature of Amberlyst 15 as oligomerization catalyst, in addition to its easy separation from products, was found to be was follows: The activity of Amberlyst 15 was 10 times larger than that of p-toluenesulfonic acid in benzene, although catalyst deactivation at high conversions was observed for Amberlyst 15 at high monomer concentrations. Styrene trimer and tetramer were dominantly produced by Amberlyst 15 at low monomer concentrations, whereas a linear dimer was obtained in 85% yield with p-toluenesulfonic acid. Characteristically, solvent polarity had almost no effect on the reaction rate and product composition in the Amberlyst 15-catalyzed oligomerization. These facts were discussed in relation to differences between the heterogeneous and homogeneous catalyses.     

富氧条件下Co/ZSM-5催化剂对C_3H_8选择还原NO_x的性能

采用多种物理化学手段研究了在模拟的轻型柴油车尾气中不同Co担载量及Cu掺杂的Co/ZSM-5催化剂的Co组分分散状态、可还原性、NO吸附脱附性质对C3H8选择性催化还原NOx性能的影响。结果表明,浸渍法制备的Co/ZSM-5催化剂上既有外表面上的Co3+和Co2+物种,也有孔内的Co2+离子。富氧条件下Co/ZSM-5催化剂上C3H8选择性催化还原NOx的活性主要与ZSM-5载体孔外表面分散的CoOx物种中的钴离子可还原能力和NO吸附脱附性能密切相关。Co/ZSM-5催化剂上适宜的Co担载量约为4.0wt%,低担载量时随Co担载量增加,表面CoOx物种中钴离子可还原能力增强,C3H8选择性催化还原NOx的低温转化活性增加;高担载量时,随Co担载量增加,单位Co离子的NO吸附量的减少以及催化剂表面活性中心数的减少,导致了Co/ZSM-5催化剂NOx的转化率和催化剂比速率(k)的下降。孔外表面Co3O4晶体的存在使催化剂表面产生较强的NO吸附,并在高温时有利于C3H8的氧化燃烧,使C3H8选择性催化还原NOx的活性降低。     

Highly efficient heterogeneous acylations of aromatic compounds with acid anhydrides and carboxylic acids by montmorillonite-enwrapped titanium as a solid acid catalyst

Montmorillonite-enwrapped titanium hydroxide species (Ti⁴⁺-mont) acted as a highly efficient heterogeneous acid catalyst for the acylation of aromatic compounds with acid anhydrides or carboxylic acids. The catalytic activity of the Ti⁴⁺-mont was higher than those of other acid catalysts such as zeolites, SO ₄ ²⁻ /ZrO₂ and p-toluenesulfonic acid. For example, the reaction of anisole with dodecanoic acid in the presence of the Ti⁴⁺-mont catalyst gave 1-(4-methoxyphenyl)-1-dodecanone in 97% yield. Furthermore, the Ti⁴⁺-mont catalyst was easily separated from the reaction mixture and was recyclable.     

富氧条件下Co/ZSM-5催化剂对C3H8选择还原NOx的性能

采用多种物理化学手段研究了在模拟的轻型柴油车尾气中不同Co担载量及Cu掺杂的Co/ZSM-5催化剂的Co组分分散状态、可还原性、NO吸附脱附性质对C₃H₈选择性催化还原NO_x性能的影响。结果表明,浸渍法制备的Co/ZSM-5催化剂上既有外表面上的Co³⁺和Co²⁺物种,也有孔内的Co²⁺离子。富氧条件下Co/ZSM-5催化剂上C₃H₈选择性催化还原NO_x的活性主要与ZSM-5载体孔外表面分散的CoO_x物种中的钴离子可还原能力和NO吸附脱附性能密切相关。Co/ZSM-5催化剂上适宜的Co担载量约为4.0wt%,低担载量时随Co担载量增加,表面CoO_x物种中钴离子可还原能力增强,C₃H₈选择性催化还原NO_x的低温转化活性增加;高担载量时,随Co担载量增加,单位Co离子的NO吸附量的减少以及催化剂表面活性中心数的减少,导致了Co/ZSM-5催化剂NO_x的转化率和催化剂比速率（k）的下降。孔外表面Co₃O₄晶体的存在使催化剂表面产生较强的NO吸附,并在高温时有利于C₃H₈的氧化燃烧,使C₃H₈选择性催化还原NO_x的活性降低。     

磁性Co/TiB2室温高效催化氨硼烷产氢及串联降解有机污染物

通过熔盐法制备TiB₂载体,并采用简单的沉淀-沉积法制备了Co/TiB₂磁性可回收纳米催化剂,用于室温催化氨硼烷（NH₃BH₃）溶液产氢及串联降解对硝基苯酚（4-NP）及偶氮染料酸性橙7（AO7）、酸性红1（AR1）和甲基橙（MO）等有机污染物。采用X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、振动样品磁强计等表征方法对催化剂的微观形貌和结构等进行分析。结果表明,Co纳米粒子均匀地分布在TiB₂载体表面,晶粒尺寸约为40 nm,并且被TiB₂载体包覆,具有典型的金属-载体强相互作用。Co/TiB₂表现出优异的室温催化NH₃BH₃溶液产氢活性,产氢速率为565.8 mol_H2·mol_cat^-1·h^-1。在串联降解有机污染物反应中,Co/TiB₂在7 min内催化4-NP氨基化的转化率接近100%,反应速率常数高达0.72 min^-1;降解AO7的反应速率常数在3种偶氮染料中最高（0.34 min^-1）。通过EPR-DMPO（EPR=电子顺磁共振,DMPO=5,5-二甲基-1-吡咯啉-N-氧化物）自由基捕获实验检测出Co/TiB₂+NH₃BH₃催化体系中产生大量的氢自由基（·H）。得益于·H的强还原性,Co/TiB₂+NH₃BH₃催化体系能够将4-NP氨基化为具有更高价值的对氨基苯酚（4-AP）,同时能够还原偶氮染料分子中的显色基团偶氮基（—N=N—）。     

Crystal structure, spectroscopic and magnetic properties, and antimicrobial activities of cobalt(II) 2-methylthionicotinate complexes with N-heterocyclic ligands

Synthesis and characterization of 10 new 2-methylthionicotinate (2-MeSnic) Co(II) complexes, namely, [Co(2-MeSnic)₂L₂(H₂O)₂] · nH₂O (L is N,N-diethylnicotinamide—Et₂nia, ethylnicotinate—Etnic, nicotinamide—nia, isonicotinamide—isonia, N-methylnicotinamide—N-Menia, furo[3,2-c]pyridine—fpy, 2,3-dimethylfuro[3,2-c]pyridine—Me₂fpy or benzo[4,5]furo[3,2-c]pyridine—Bfp; n is 0, 1 or 2) as well as [Co(2-MeSnic)₂L₂] (L is ronicol—ron or 2-methylfuro[3,2-c]pyridine—Mefpy), are reported. The characterizations were based on physico-chemical and spectroscopic methods. The crystal structure of one of the complexes has been determined. In the molecular complex [Co(2-MeSnic)₂(Me₂fpy)₂(H₂O)₂], the Co(II) central atom, located at a symmetry centre, is octahedrally coordinated by an oxygen atom of the unidentate 2-MeSnic carboxyl group, the nitrogen atom of the pyridine ring of Me₂fpy, a water molecule and the corresponding centrosymmetrically located atoms. Also, biological activity of the complexes against various strains of bacteria and filamentous fungi has been investigated. It is concluded that by complexation of these nicotinate derivatives their biological activities are elevated. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

SnCl4-Catalyzed Aza-Acetalization of Aromatic Aldehydes: Synthesis of Aryl Substituted 3,4-Dihydro-2H-1,3-benzoxazines

Stannic tetrachloride was an efficient Lewis acid catalyst for the aza-acetalization of aromatic aldehydes with o-arylaminomethyl phenols, and a series of novel aryl substituted 3,4-dihydro-2H-1,3-benzoxazines were prepared in good yields under mild conditions. SnCl₄ was a more efficient catalyst for the reaction than p-toluenesulfonic acid, sulfuric acid, and aluminium chloride.     

双配体CuFe@MOFs材料为前驱体的催化剂的组分调控对CO2加氢制C2+醇性能的影响

采用水热法制备了以对苯二甲酸和对氨基苯甲酸为配体的双配体Fe基MOFs材料(MIL-88B(Fe)),在浸渍一定量Cu物种后经氮气气氛焙烧得到活性组分均匀分散的CuFe基催化剂。通过改变2种配体的比例调控催化剂表面Fe活性物种的价态分布,并考察了其用于固定床反应器上CO_2加氢制C_(2+)醇的催化性能,结合X射线衍射(XRD)、H_2程序升温还原(H2-TPR)、N_2吸附-脱附、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)等表征结果发现,对苯二甲酸与对氨基苯甲酸物质的量之比为5∶2时,催化剂表面低价态铁原子占比为71.27%,催化剂展现最优的催化活性,CO_2转化率为8.80%,总醇选择性为31.52%,其中C_(2+)醇的物质的量分数达到94.70%。     

A one-pot four-component synthesis of N-arylidene-2-aryl-imidazo[1,2-a]azin-3-amines

N-Arylidene-2-aryl-imidazo[1,2-a]azin-3-amines were synthesized via a one-pot, four-component condensation reaction using a 2-aminoazine, toluene-4-sulfonylmethyl isocyanide (TsCH₂NC), and two equivalents of readily available aromatic aldehydes. The reaction was performed in diethyl ether as the solvent, with p-toluenesulfonic acid (p-TSA) as the catalyst at reflux temperature.     

Regio- and stereoselective synthesis of functionalized oxazolidin-2-ones from the reaction of α-epoxyketones with urea

A regio- and stereoselective synthesis of functionalized 4,5-disubstituted oxazolidin-2-ones is reported with moderate to good yields from the reaction of α-epoxyketones with urea in the presence of p-toluenesulfonic acid as the catalyst.     

Azocalixarenes. 6: Synthesis, complexation, extraction and thermal behaviour of four new azocalix[4]arenes

Four new azocalix[4]arenes {5,11,17,23-tetrakis[(2-hydroxy-5-tert-butylphenylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (1), 5,11,17,23-tetrakis[(2-hydroxy-5-nitro phenylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (2), 5,11,17,23-tetrakis[(2-amino-5-carboxylphenylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (3) and 5,11,17,23-tetrakis[(1-amino-2-hydroxy-4-sulfonicacidnapthylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (4)} have been synthesized from p-tert-butylphenol, p-nitrophenol, p-aminobenzoic acid and 1-amino-2-hydroxy-4-sulphonic acid by diazo coupling reaction with p-aminocalix[4]arene. The resulting ligands (1–4) were treated with three transition metal salts (e.g., CuCl₂·2H₂O, NiCl₂·6H₂O or CoCl₂·6H₂O). Cu(II), Ni(II) and Co(II) complexes of the azocalix[4]arene derivatives were obtained and characterized by UV-vis, IR, ¹H-NMR spectroscopic techniques and elemental analysis. All the complexes have a metal:ligand ratio of 2:1. The Cu(II) and Ni(II) complexes of azocalix[4]arenes are square-planar, while the Co(II) complexes of azocalix[4]arenes are octahedral with water molecules as axial ligands. The solvent extraction of various transition metal cations from the aqueous phase to the organic phase was carried out by using azocalix[4]arenes (1–4). It was found that, azocalix[4]arenes 1, 2 and 3 examined selectivity for transition metal cations such as Ag⁺, Hg⁺ and Hg²⁺. In addition, the thermal stability of metal:azocalix[4]arene complexes were also reported. Dedicated to Prof. Dr. Mustafa Yılmaz on the occasion of his 50th birthday     

酸功能化-温控型三元杂多酸离子液体的合成、表征及其酯催化性能

采用酸化-乙醚萃取法制备了不同钒取代数目的 Keggin结构的磷钨钒杂多酸,并进一步通过离子交换法合成了磺酸功能化的杂多酸离子液体催化剂,采用核磁、元素分析、红外、紫外、X射线衍射、热重-差示扫描、电位滴定等分析手段对所得样品进行了表征,考察了所得样品对氯乙酸和正戊醇的酯化反应性能和重复使用性能。结果表明,所制备的杂多酸离子液体是一种具有温度响应特性的无定型结构化合物,仍保留Keggin结构和较高的酸强度,该催化剂在反应温度下与反应物形成一相,而反应结束温度降低后,催化剂和产物又形成两相,通过简单的倾倒法就可以快速分离催化剂和反应产物。与杂多酸以及未磺酸化的杂多酸离子液体相比,磺酸功能化的杂多酸离子液体具有更高的酯催化活性。在优化的反应条件下,[PyPS]4PW11VO40(PyPS为1-(3-磺酸基)丙基吡啶)对氯乙酸的转化率可达到97.6%,重复使用4次后转化率为91.9%,而催化剂的结构未有明显变化。     

First sonochemical,simple and solvent-free synthesis of chiral tert-butanesulfinimines using silica supported p-toluenesulfonic acid

A solvent-free, versatile procedure has been developed for the effective synthesis of tert-butanesulfinylimines of a variety of aldehydes using chiral tert-butanesulfinamides under green, sonochemical conditions. This method utilizes silica supported p-toluenesulfonic acid (pTSA·SiO₂) as an efficient, safer and inexpensive catalyst under aerobic conditions. The practicable simplicity, easy preparation of the catalyst from readily available substances, high substrate scope, excellent yields of products in short reaction times and environmentally benign (solvent-free sonochemical) conditions are the exceptional assets of this finding.     

Reactions ofn-hexane andn-nonane on Pt catalysts and hydrogenating off hydrocarbonaceous adspecies after reaction

n-Hexane andn-nonane were reacted on Pt black, 6% Pt/SiO₂, 0.8% Pt/KL zeolite and a 0.6% industrial Pt/Al₂O₃ catalyst. Selectivities were compared at ∼10% conversion. After reaction, the catalyst was exposed to H₂ and the hydrocarbons leaving the catalysts were analyzed. The amount of hydrocarbons left the catalysts decreased in the sequence Pt black>Pt/SiO₂>Pt/KL>Pt/Al₂O₃. The composition of removed hydrocarbons gave important—although indirect—information on the possible state of “hydrocarbonaceous deposits” during catalysis.     

水解动力学拆分3-(1-萘氧基)-1,2-环氧丙烷

研究了3-(1-萘氧基)-1,2-环氧丙烷[(R,S)-1]在Salen Co(Ⅲ)催化下的水解动力学拆分(HKR)。以转化率和ee值为指标,考察了催化剂用量、底物用量、反应温度、反应时间、溶剂种类等对HKR反应的影响。最佳HKR条件为:(R,S)-1 10 mmol,w[Salen Co(Ⅲ)]=0.75%,THF 1 mL,水0.5 eq,于25℃水解40 h,(R,S)-1的转化率为49.5%,(S)-1的ee为99.5%。     

Quantum-chemical investigation of the mechanisms of oxidation of dimethyl sulfide by hydrogen peroxide and peroxoborates

It was established by the DFT method in the B3LYP/6-311G-d,p approximation that the oxidation of dimethyl sulfide (Me₂S) by peroxides (XOOH) can take place by two mechanisms depending on the nature of X. In the reaction of Me₂S with hydrogen peroxide (X = H) the direct reagent is the HOOH molecule while in the reactions with monoperoxoborate [X = B(OH)₃] and diperoxoborate [X = B(OH)₂OOH] it is a reagent containing the “water oxide” fragment X—(⁺OH)—O^–.