绿色可磁性分离二氧化硅包裹镍铁尖晶石负载硫酸氢铁纳米粒子催化剂用于合成1,8-二氧十氢吖啶合成Amir Khojastehnezhad,Mohammad Rahimizadeh,简

A new magnetically separable catalyst consisting of ferric hydrogen sulfate supported on silica-coated nickel ferrite nanoparticles was prepared. The synthesized catalyst was characterized using vibrating sample magnetometry, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. This new magnetic catalyst was shown to be an efficient heterogeneous catalyst for the synthesis of 1,8-dioxodecahydroacridines under solvent-free conditions. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.     

绿色可磁性分离二氧化硅包裹镍铁尖晶石负载硫酸氢铁纳米粒子催化剂用于合成1,8-二氧十氢吖啶合成(英文)

A new magnetically separable catalyst consisting of ferric hydrogen sulfate supported on silica-coated nickel ferrite nanoparticles was prepared.The synthesized catalyst was characterized using vibrating sample magnetometry,X-ray diffraction,transmission electron microscopy,scanning electron microscopy,and Fourier transform infrared spectroscopy.This new magnetic catalyst was shown to be an efficient heterogeneous catalyst for the synthesis of 1,8- dioxodecahydroacridines under solvent-free conditions.The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.     

混合金属氧化物固载杂多酸的制备及催化性能

杂多酸是一类含氧桥的多核无机高分子化合物,由于其独特的笼型结构而具有许多优异的性能,尤其是作为一种新型的多功能催化剂越来越受到人们的关注。因此,近年来人们一直致力于研究新型固载杂多酸催化剂。本文介绍了钛钨混合金属氧化物固载杂多酸催化剂HPA／TiO2-WO3的制备,及催化合成甲酸环己酯的方法,此法具有反应时间短、催化剂价廉易得、工艺简单、酯产率较高等优点。     

一种新型高比表面积 TiO2载体在 NH3选择性催化还原反应中对 V2O5分散性的促进作用

A titania support with a large surface area was developed, which has a BET surface area of 380.5 m2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt%vanadia. A special heat treatment was used in the calcination to maintain the large sur‐face area and high dispersion of vanadium species. This catalyst was compared to a common V2O5‐TiO2 catalyst with the same vanadia loading prepared by a traditional method. The new cata‐lyst has a surface area of 117.7 m2/g, which was 38%higher than the traditional V2O5‐TiO2 catalyst. The selective catalytic reduction (SCR) performance demonstrated that the new catalyst had a wid‐er temperature window and better N2 selectivity compared to the traditional one. The NO conver‐sion was>80%from 200 to 450 °C. The temperature window was 100 °C wider than the traditional catalyst. Raman spectra indicated that the vanadium species formed more V‐O‐V linkages on the catalyst prepared by the traditional method. The amount of V‐O‐Ti and V=O was larger for the new catalyst. Temperature programmed desorption of NH3, temperature programmed reduction by H2 and X‐ray photoelectron spectroscopy results showed that its redox ability and total acidity were enhanced. The results are helpful for developing a more efficient SCR catalyst for the removal of NOx in flue gases.     

Ni-Mo2N/SiO2复合纳米催化剂的制备及其对四氢萘加氢的催化活性

采用程序升温氮化法制备了Mo2N/SiO2,在此基础上负载Ni盐,制备了Ni-Mo2N/SiO2复合纳米催化剂,并考察了催化剂对四氢萘加氢的催化活性.结果表明,与Ni2Mo3N/SiO2及Ni/SiO2催化剂相比,Ni-Mo2N/SiO2复合催化剂具有较高的催化活性.采用"分离床"方法研究了Ni和Mo2N对四氢萘加氢活性的影响.通过X射线粉末衍射、透射电镜、氢吸附、元素分析和比表面积测定等技术对Ni-Mo2N/SiO2催化剂进行了表征.结果表明,与Ni/SiO2催化剂相比,Ni-Mo2N/SiO2复合催化剂中Ni的分散度并未提高;催化活性的提高归因于Ni与Mo2N在四氢萘加氢中的协同作用.氮化物的引入增加了芳烃吸附活性位的数目.提出了四氢萘在Ni-Mo2N/SiO2催化剂上的可能加氢机理.     

提高非贵金属临氢脱腊催化剂异构化能力的研究

通过水热条件下合成分子筛试验条件的考察,获得了合成条件和性能良好的ZSM-8分子筛。采用无定形硅铝和ZSM-8分子筛制备出复合载体型的非贵金属临氢脱腊催化剂,通过锌和钨改性组分的添加,提高现有工业催化剂的异构化能力。实验结果表明,不同复合载体、改性组分对催化性能有较大影响,但改性组分的添加次序无明显作用。与以前β沸石基催化剂性能相比,ZSM-8基催化剂不仅提高了润滑油收率,而且产品润滑油的粘度指数也明显提高。催化性能的改进可以归结为改性后催化剂异构化能力的提高。     

Development of new asymmetric two-center catalysts in phase-transfer reactions

A new asymmetric two-center phase-transfer catalyst was designed and a catalyst library containing more than 40 new two-center catalysts was constructed. The catalysts were applied in phase-transfer alkylations and Michael additions to afford the corresponding products in up to 93% ee and 82% ee, respectively.     

Nicotinic acid functionalized organomodified silica as an efficient heterogeneous catalyst for the synthesis of benzoyl fumarate

A new hybrid catalyst has been developed by incorporating nicotinic acid onto an organomodified silica. The catalyst was applied as a heterogeneous catalyst for the synthesis of benzoyl fumarate. The reactions work well in the presence of 20 wt % of the catalyst at room temperature to produce the desired products in high yield. The catalyst could be recovered and reused without appreciable change in activity.     

新型糠醛加氢制糠醇催化剂研究

新型糠醛加氢制糠醇催化剂研究林培滋，黄世煜，周焕文，赵彤彤，刘崇早，罗洪原，梁东白（中国科学院大连化学物理研究所，大连１１６０２３）关键词铜催化剂，糠醛，加氢，糠醇糠醇是重要的化工原料，糖醇树脂是耐酸、碱腐蚀的材料，在工业发达的国家中，铸造工业广泛采...     

A Lewis acid-Lewis base bifunctional catalyst from a new mixed ligand

Covalent attachment of quinine to a salen framework through a racemic linker gave a new mixed ligand in a 1:1 diastereomeric mixture, from which an active Lewis acid-Lewis base (LA*-LB*) bifunctional catalyst derived from Co(II) was discovered by the screening of metal complexes. The remarkable intramolecular bifunctional catalytic activity (1 mol % catalyst loading) of the new catalyst was demonstrated using a proof-of-principle reaction. [reaction: see text].     

奎宁-杂多酸杂化催化剂催化H2O2为氧源的苯羟基化反应

将奎宁与Keggin结构磷钼钒杂多酸结合制备出一种新颖的多相苯羟基化杂化催化剂, 采用傅里叶变换红外光谱、紫外-可见光谱、X射线衍射、扫描电镜、热重、N₂吸附-脱附和CHN元素分析等表征手段对催化剂进行了分析. 结果表明, 该催化剂是一种具有较高比表面积和孔体积的半无定形有机杂多酸盐. 在H₂O₂为氧源的苯羟基化反应中, 杂化催化剂引导了液-固两相催化体系, 表现出较高催化活性和重复使用稳定性. 催化剂中奎宁与杂多阴离子间的氢键和电子相互作用赋予了其高熔点和难溶性, 而高比表面积和因奎宁而改善的杂多阴离子的氧化还原性是其获得优异催化性能的主要原因. 这为多相苯羟基化反应提供了一种新的且制备便捷的基于多金属氧酸盐的高效催化剂.     

A new stable Hoveyda-Grubbs catalyst with mixed anionic ligands

The synthesis and characterisation of a new highly active Hoveyda-Grubbs 2nd generation type catalyst is described. Substitution of one chloride ligand with a partially fluorinated trialkoxysilyl substituted carboxylate leads to the stable monocarboxylate ruthenium catalyst (3). This catalyst represents the first example of a stable and isolable mono-chloride exchanged carboxylate complex suitable for both homogeneous and heterogeneous metathesis. The reactivity of the new catalyst was tested in representative metathesis reactions and offers an activity comparable to the parent dichloride system (1).     

锌对非晶态Co-B合金的改性及催化肉桂醛加氢为肉桂醇的研究

采用KBH4还原法制备了非晶态Co-B和Co-Zn-B催化剂,以肉桂醛选择加氢制肉桂醇为探针反应,研究了Zn对Co-B非晶态催化剂的修饰改性作用,并采用XRD、DSC、XPS、和H2-TPD对催化剂进行了表征.研究表明,少量的Zn没有改变Co-B催化剂的非晶结构,但提高了催化剂主体的热稳定性,其中1%的Zn可使Co-B非晶态催化剂主体结晶放热峰提高12K,并在665K出现新的H2脱附峰,说明催化剂因掺入锌形成了新的氢吸附中心,锌在催化剂中以金属态和氧化态两种形式存在.催化剂的整体均衡而局部电子分布不均衡的缺陷势结构增强了对肉桂醛分子C=O双键O原子的侧链偶合吸附与金属氧化物的金属离子对羰基的极化作用协同活化了肉桂醛的C=O双键,提高了催化剂对C=O双键的加氢选择性.加氢反应工艺条件及催化剂寿命研究表明,适宜的反应温度为413K,氢压为2.5MPa,反应时间为3.0h,肉桂醇的最高产率可达84.0%,并具有较好的催化稳定性.     

New Rh—ZnO／Carbon Nanotubes Catalyst for Methanol Synthesis

A new catalyst for methanol synthesis,ZnO-promoted rhodium supported on carbon nanotubes,was developed.It was found that the Rh-ZnO/CNTs catalyst had high activity of 411.4mg CH3OH/g/cat/h and selectivity of 96.7% for methanol at 1 MPa and 523 K.The activity of this catalyst is much higher than that of NC 207 catalyst at the same reaction conditions.It was suggested that the multi-walled strueture CNTs favored both the couple transfer of the proton and clectron over the surface of the catalyst and the uptake of hydrogen which was favorable to methanol synthesis.     

Kinetic study of dichlorocyclopropanation of 4-vinyl-1-cyclohexene by a novel multisite phase transfer catalyst

In this work, the dichlorocyclopropanation of 4-vinyl-1-cyclohexene catalyzed by a new novel phase transfer catalyst was carried out in an alkaline solution/chloroform two-phase medium. This new synthesized phase transfer catalyst, 1,4-bis(triethylmethylammonium)benzene dichloride (DC-X), which possesses two-site activity, was obtained from the reaction of ,′-dichloro-p-xylene and triethylamine. This new novel phase transfer catalyst exhibits higher reactivity than those of the other quaternary ammonium salts. The reaction of chloroform and alkali was carried out at the interface to generate dichlorocarbene which can further react with 4-vinyl-1-cyclohexene to produce mono-dichlorocyclopropane and bis-dichlorocyclopropane products. Rational mechanism of the dichlorocyclopropanation is proposed according to the experimental evidence. The reaction follows a pseudo-first-order rate law. Kinetics of the reactions such as: effect of the catalysts, agitation speed, temperature, alkaline concentration, amount of DC-X catalyst, amount of 4-vinyl-1-cyclohexene (reactant) and volume of chloroform (organic solvent) on the reaction rate were investigated in detail. Peculiar phenomenon for the dependence of the reaction rate on the amount of DC-X catalyst is explained satisfactorily.     

Novel magnetic nanoparticles with morpholine tags as multirole catalyst for synthesis of hexahydroquinolines and 2-amino-4,6-diphenylnicotinonitriles through vinylogous anomeric-based oxidation

Research on Chemical Intermediates - A new heterogeneous nanomagnetic catalyst bearing morpholine tags was synthesized and characterized. The formation of the nanomagnetic catalyst was fully...     

Synthesis of Chiral Metal Complexes of Unsymmetrical Schiff Bases

Recently, in asymmetric catalyst research the great developments of chiral Salen complexes have been made, but the report on unsymmetrical schiff bases is deficient. The unsymmetrical schiff bases complexes are an effective system in catalytically selective Olefin-epoxidations1. At the same time, unsymmetrical schiff bases was immobilized onto polymer supports for heterogenization2. The potential benefits of the catalyst include facilitation of catalyst separation from reagents, simplification of methods for catalyst recycle, and the possible adaptation of the immobilized catalyst to continuous-flow processes. A series of new unsymmetrical schiff bases was synthesized to study the relations between unsymmetry and enantioselectivity and select better catalyst. The following is the route:     

Designing a capsule catalyst and its application for direct synthesis of middle isoparaffins

A catalyst in the form of a capsule catalyst was prepared by coating HZSM5 membrane on a preshaped Co/SiO2 catalyst pellet. The capsule catalyst with HZSM5 membrane exhibited excellent selectivity for light hydrocarbon synthesis, especially for isoparaffin synthesis from syngas (CO + H2). Long-chain hydrocarbon formation was totally suppressed by the zeolite membrane. The modification of membrane and core catalyst significantly improved the catalytic properties of these new kinds of capsule catalysts.     

新型（Salen）Co催化剂催化合成沙丁胺醇

以（Salen）Co-GaC13为催化剂,拆分2-乙酰氧基5-环氧乙基-乙酸苄酯以得到R-型产品,设计新的手性沙丁胺醇的合成路线.结果表明,以（Salen）Co-GaCl3为催化剂、异丙醇为溶剂、水为亲核试剂,拆分2-乙酰氧基-5-环氧乙基-乙酸苄酯所得的产品光学纯度达到97.36％ ee.该方法催化剂廉价易得,拆分过程简便、成本低廉,具备工业化生产的潜力.     

Various activation procedures of Phillips catalyst for ethylene polymerization

Nowadays, the Phillips CrO_x/SiO₂ catalyst is still attracting interest from both industrial and academic fields owing to its unique characteristics for HDPE production. Compared with other industrial catalysts for ethylene polymerization, the Phillips catalyst can be activated by ethylene monomer, CO or Al-alkyl cocatalyst after a simple calcination process (thermal activation). In this work, a brief review of our recent new understanding on various activation procedures, including thermal activation, monomer activation, and CO activation, on industrial Phillips catalyst was presented. A new initiation mechanism, ethylene metathesis mechanism, was proposed according to some experimental evidence during the induction period when ethylene monomer was used to activate the catalyst. Such an ethylene metathesis mechanism was also indirectly confirmed in CO-prereduced Phillips catalyst. The formation of short chain branches in polymer can be rationalized well by this newly proposed unique mechanism during ethylene homo-and copolymerization with hexene-1 using CO-prereduced Phillips catalyst in the presence of triethylaluminum cocatalyst.