共查询到14条相似文献,搜索用时 62 毫秒
1.
2.
《丙烯酸化工与应用》2002,15(3):44-45
一种以异西烯或叔丁醇为原料两步法制取甲基丙烯酸的催化剂,以及制备方法,一段催化剂的组成通式是MO10 BiaFebX-cYdZeOf,二段催化剂的组成通式是MO12Pa1Asb1Vc1Ad1De1Of1,一段和二段催化剂所使用的贵金属元素少、成本低,而且催化剂组分不易发生流失,稳定性好,使用本发明催化剂制取甲基丙烯酸的反应,可以达到异丁烯或者叔丁酯转化率100%,甲基丙烯酸单程收率60%(mol)以上,甲基丙烯醛单程收率10%(mol)左右。 相似文献
3.
过渡金属氧化物催化剂对丙酮氧化的催化性能 总被引:1,自引:0,他引:1
以氧氯化锆和过渡金属硝酸盐为原料,溶胶-凝胶法制备氧化锆载体,采用溶液浸渍法制备出负载型纳米复合氧化物催化剂。对过渡金属氧化物(Mn、Ni、Cu、Fe和Co)催化剂进行初步筛选,其中Mn2O3/ZrO2催化活性最佳。考察了活性组分含量、焙烧温度和焙烧时间等对催化剂催化活性的影响。催化剂的最佳制备条件:锰负载量为6%,450 ℃焙烧6 h。丙酮的转化率达62%。通过TEM、SEM、XRD和TG-DTA对催化剂结构进行了表征。结果显示,催化剂颗粒均匀,大小约为20 nm;无定形的Mn2O3是催化剂的活性中心。 相似文献
4.
5.
Hao-Yu Shen Li-Yan Ying Hai-Liang Jiang Zaher M. A. Judeh 《International journal of molecular sciences》2007,8(6):505-512
The selective oxidation of alcohols with molecular oxygen was efficiently completed in high conversion and selectivity using copper-bisisoquinoline-based catalysts under mild reaction condition. The effects of various parameters such as reaction temperature, reaction time, oxidant, ligands, etc, were studied. Solvent effect has been as well studied in ionic liquids [bmim]PF6, [omim]BF4 and [hmim]BF4, comparing to traditional volatile organic solvent. The use of ionic liquids was found to enhance the catalytic properties of the catalysts used. 相似文献
6.
Laxmidhar Rout Pinku Nath Tharmalingam Punniyamurthy 《Advanced Synthesis \u0026amp; Catalysis》2007,349(6):846-848
The oxidation of alcohols to aldehydes and ketones has been described using silica‐supported vanadium(IV ) oxide (V/SiO2, 1 ) in the presence of tert‐butyl hydroperoxide in tert‐butyl alcohol at ambient temperature with quantitative yields. The procedure is simple, efficient and environmentally benign. 相似文献
7.
Mario Debruyn DirkE. DeVos PierreA. Jacobs 《Advanced Synthesis \u0026amp; Catalysis》2002,344(10):1120-1125
α,β‐Unsaturated ketones were reduced to allylic alcohols with high chemo‐ and diastereoselectivity, using Zr and Hf compounds heterogenised on mesoporous molecular sieves. 相似文献
8.
The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like dienones. Six pyridinium ionic liquids were evaluated in allylic oxidation of α-ionone and β-ionone. The 60%–70% yields of 3-oxo-α-ionone were obtained with 0.02-0.20 mmol of CuCl28226;2H2O as catalyst, 3-5 mmol of tert-butyl hydroperoxide as oxidant and 1 g of [Bpy]PF6 as solvent for 4-20 h at 60°C. The facile recovery and recycle of catalyst were also achieved. More significantly, peculiar phase behaviors of [Bpy]PF6 and [Epy]PF6 offered the catalytic system advantages of homogeneous reaction and heterogeneous separation. Scanning electron microscope (SEM) images of [Bpy]PF6 provided evidences for the behaviors. Transmission electron microscope (TEM) micrographs showed copper salt nanoparticles catalyst formed and stabilized in pyridinium ionic liquids. 相似文献
9.
Supported Au catalysts are investigated for the oxidation of primary alcohols under solvent-free conditions in the absence of base. Three representative primary alcohols have been investigated: benzyl alcohol, octan-1-ol and geraniol using a range of supports for gold nanocrystals prepared using coprecipitation, deposition precipitation and impregnation. For benzyl alcohol and octan-1-ol selective oxidation to the corresponding aldehydes is observed, particularly with Au/CeO2, whereas for more acidic supports, e.g. Fe2O3, subsequent oxidation of the aldehydes to the corresponding acids, forming an ester (benzyl benzoate, octyl octanoate, respectively) by reaction with the alcohol, by a standard acid-catalysed mechanism. Alternatively, the mechanism of ester generation could involve hemiacetal formation between the aldehyde and residual alcohol, followed by direct oxidation to the observed ester. The reaction of geraniol is much more complex and the reaction is carried out in the presence and absence of acids to gain a full understanding of the interplay between oxidation and isomerisation reactions. Comparison with other active catalysts reveals that using Au catalysts in solvent free conditions gives very high turnover frequencies for the synthesis of the aldehydes with 100% selectivity (150 h−1 and 26 h−1 for benzyl alcohol and octan-1-ol, respectively), which are comparable to the best reported to date for these reactions. 相似文献
10.
Benoît Join Konstanze Mller Carolin Ziebart Kristin Schrder Dirk Grdes Kerstin Thurow Anke Spannenberg Kathrin Junge Matthias Beller 《Advanced Synthesis \u0026amp; Catalysis》2011,353(16):3023-3030
A convenient and selective oxidation of alcohols with hydrogen peroxide to give aldehydes and ketones has been developed. Using in situ generated iron chloride complexes [Fe( L3 )2Cln] [n=0–1, L3 =6‐(N‐phenylbenzimidazoyl)‐2‐pyridinecarboxylic acid], aldehydes and ketones were obtained in good yield and excellent selectivity after a short reaction time at room temperature. 相似文献
11.
Shengming Ma Jinxian Liu Suhua Li Bo Chen Jiajia Cheng Jinqiang Kuang Yu Liu Baoqiang Wan Yuli Wang Juntao Ye Qiong Yu Weiming Yuan Shichao Yu 《Advanced Synthesis \u0026amp; Catalysis》2011,353(6):1005-1017
Oxidation of alcohols is a fundamental transformation related to our daily life. Traditional approaches with at least one stoichiometric amount of oxidants are expensive and cause serious environmental burdens. There are many reports on the aerobic oxidation of simple alcohols such as alkyl or phenyl carbinols and allylic alcohols, which used oxygen or air as the environmentally benign oxidant forming water as the only by‐product. However, no such protocol has been reported for allenols and propargylic alcohols. Thus, it still highly desirable to develop efficient room temperature oxidations of alcohols with a wide scope including allenols and propargylic alcohols. In this paper, an efficient and clean aerobic oxidation of so far the widest spectrum of alcohols using 1 atm of oxygen or air, producing aldehydes/ketones at room temperature in fairly high isolated yields mostly within a couple of hours is described. It is interesting to observe that the reaction has been efficiently expedited by a catalytic amount of sodium chloride in easily recoverable 1,2‐dichloroethane. A mechanism involving NO and NO2 has been proposed based on the results of the control experiments and GC‐MS studies of the in‐situ formed gas phase of the reaction mixture. 相似文献
12.
Patrick Gamez IsabelW.C.E. Arends RogerA. Sheldon Jan Reedijk 《Advanced Synthesis \u0026amp; Catalysis》2004,346(7):805-811
A novel and very mild method for the oxidation of primary alcohols to aldehydes with excellent conversions has been developed. The reaction is carried out under air at room temperature and is catalysed using a [copper(II)‐(N ligand)n] complex with TEMPO and a base as co‐catalysts. In this paper, the performance of a series of N‐containing ligands, as well as different copper(II) salt precursors in different solvents are reported. Best results are obtained in acetonitrile/water as solvent using a copper(II) catalyst generated in situ from a Cu(II) salt with weak or non‐coordinating anions and bipyridine ligands with electron‐donating substituents. A reaction mechanism is postulated which resembles that of galactose oxidase, and in which TEMPO seems to be involved as a hydrogen acceptor. 相似文献
13.
The isomerisation of alkenols followed by reaction with aldehydes or N‐tosylimines catalysed by rhodium complexes has been studied. The catalytically active rhodium complex is formed in situ from commercially available (cyclooctadiene)rhodium(I) chloride dimer [Rh(COD)Cl]2. The tandem process affords aldol and Mannich‐type products in excellent yields. The key to the success of the coupling reaction is the activation of the catalysts by reaction with postassium tert‐butoxide (t‐BuOK), which promotes a catalytic cycle via alkoxides rather than rhodium hydrides. This mechanism minimises the formation of unwanted by‐products. The mechanism has been studied by 1H NMR spectroscopy and deuterium labelling experiments. 相似文献
14.
P.G.N. Mertens P. Vandezande X. Ye H. Poelman D.E. DeVos I.F.J. Vankelecom 《Advanced Synthesis \u0026amp; Catalysis》2008,350(9):1241-1247
Pre‐formed polyvinylpyrrolidone‐stabilized gold‐palladium clusters, consisting of 80 mol% gold and with a mean size of 1.9 nm, were immobilized quantitatively in a porous polyimide membrane via the process of phase inversion, without loss of metal nanodispersion. The obtained gold‐palladium/polyimide membrane emerged as a highly active heterogeneous metal catalyst for the amide‐phase and solvent‐free oxidation of aliphatic, allylic and benzylic alcohols with full selectivity to the corresponding aldehydes and ketones, and could be recycled with excellently preserved catalytic activity and product selectivity. Occlusion of the optimized bimetallic clusters in the polyimide structure proved beneficial in view of their superior catalytic performance compared to the analogous colloidal gold‐palladium clusters. 相似文献