离子液体中V2O5催化环己烯选择氧化合成 2-环己烯酮

研究了以V2O5为催化剂,H2O2为氧化剂,在室温离子液体中环己烯氧化制备2-环己烯酮的反应.考察了离子液体种类、反应温度、催化剂用量和氧化剂用量等因素对2-环己烯酮产率的影响.结果表明,在H2O2用量为110 mmol,V2O5/环己烯摩尔比为2%,反应温度为313 K的条件下,在[bmim]BF4离子液体中反应10 h后,环己烯的转化率和2-环己烯酮选择性分别为88.7%和91.1%.对含离子液体的催化体系的重复使用性能进行了考察.结果发现,随着使用次数的增加,环己烯的转化率以及2-环己烯酮的选择性有所下降.     

阳离子交换树脂/H_2O_2体系催化氧化环己烯的研究

在以改性阳离子交换树脂为催化剂、H2O2为氧化剂的催化氧化体系中,主要研究和考察了环己烯直接氧化制备1,2-环己二醇的反应,并优化得到了最佳合成工艺,在无溶剂,H2O2与环己烯的摩尔比为1.0:1.0、反应温度为70℃、反应时间为6.5h、催化剂用量为环己烯摩尔量10%的反应条件下,环己烯的转化率大于99.0%,产品1,2-环己二醇的选择性大于98.0%。阳离子交换树脂催化剂重复使用12次未见其活性和选择性明显下降。在此反应条件下,直链状的1-己烯也可高效和高选择性地转化为1,2-己二醇。     

三缺位Keggin型磷钨杂多酸盐高选择性催化氧化环己烯

利用三缺位Keggin型杂多酸[A-α-PW9O34]9-和[(FeШ(OH2)2)3(A-α-PW9O34)2]9-的四丁基铵盐做为催化剂,H2O2做为氧化剂催化环己烯氧化反应. 考察了反应时间、H2O2与环己烯的摩尔比,催化剂的用量等因素对反应结果的影响. 结果表明：在1, 2-二氯乙烷为10 mL,H2O2 (30 %)与环己烯的摩尔比为2,反应温度为35 oC,反应时间为6 h,[(C4H9)4N]9[A-α-PW9O34]为催化剂的条件下,环己烯氧化反应的转化率为55 %,主要产物是环氧环己烷,其选择性 ≥ 99 %;而以[(C4H9)4N]9[(FeШ(OH2)2)3(A-α-PW9O34)2]为催化剂时环己烯氧化反应的转化率17 %,主要产物是2-环己烯-1-酮,选择性 ≥ 99 %.     

五氧化二钒催化环己烯烯丙位氧化

 研究了以五氧化二钒为催化剂,以过氧化氢水溶液为氧源氧化环己烯. 考察了溶剂种类、溶剂用量、催化剂用量和反应温度等因素对催化剂性能的影响. 结果表明,常温下环己烯在此催化体系中主要发生烯丙位氧化反应生成环己烯酮. 溶剂的种类对催化活性和烯丙位酮式氧化的选择性具有较大的影响,丙酮是该反应的合适溶剂. 在丙酮与环己烯的体积比为4, 五氧化二钒与环己烯的质量比为1∶40, 过氧化氢与环己烯的摩尔比为3和反应温度为20 ℃的条件下,反应24 h后的环己烯转化率可达60%以上,环己烯酮选择性可达85%. 催化反应过程中丙酮可能与过氧化氢作用生成过氧化酮,从而进行氧转移,催化剂则经过V5+/V4+物种的循环使环己烯氧化成为环己烯酮等产物.     

8-羟基喹啉对V2O5催化氧化环己烯的调变作用

研究了8-羟基喹啉对丙酮中V2O5催化氧化环己烯合成环己烯酮的调变作用,考察了8-羟基喹啉的用量、反应温度、反应时间、溶剂和催化剂用量对环己烯氧化反应的影响,发现在该催化体系中生成的环己烯醇和环氧环己烷可转化成环己烯酮,在适当的反应条件下可抑制环己烯醇和环氧环己烷的生成.结果表明,当五氧化二钒的用量为1%,五氧化二钒与8-羟基喹啉之比为1∶2,在20℃以下反应时,过氧化氢几乎定向地将环己烯氧化成环己烯酮.认为是8-羟基喹啉与钒的配位作用促进了环己烯酮的生成.     

Keggin类杂多化合物催化α,β-不饱和羰基化合物环氧化

在乙睛溶剂中考察了一系列杂多化合物和过氧化氢水溶液催化的各种缺电子的α,β-不饱和羰基化合物的环氧化反应.在所研究的杂多化合物中,二缺位的[γ-SiW10(H2O)2O34](Bu4N)4显示出了最高的活性.     

反应修饰剂ZnSO_4和预处理对苯选择加氢制环己烯Ru-Zn催化剂性能的影响

共沉淀法制备了Ru-Zn催化剂,考察了反应修饰剂ZnSO_4和预处理对苯选择加氢制环己烯Ru-Zn催化剂性能的影响。结果表明,反应修饰剂ZnSO_4可以与Ru-Zn催化剂中助剂Zn O反应生成(Zn(OH)2)3(ZnSO_4)(H_2O)盐。随反应修饰剂ZnSO_4浓度增加,(Zn(OH)2)3(ZnSO_4)(H_2O)盐量逐渐增加,Ru-Zn催化剂活性逐渐降低,环己烯选择性逐渐升高。因为(Zn(OH)2)3(ZnSO_4)(H_2O)盐中的Zn2+可以使Ru变为有利环己烯生成的缺电子的Ruδ+物种,而且还可以占据不适宜环己烯生成的强Ru活性位。但当反应修饰剂ZnSO_4浓度高于0.41 mol·L-1后,继续增加ZnSO_4浓度,由于Zn2+水解浆液酸性太强,可以溶解部分(Zn(OH)2)3(ZnSO_4)(H_2O)盐,RuZn催化剂活性升高,环己烯选择性降低。环己烯选择性略微降低,是由于ZnSO_4溶液中大量的Zn2+可以与生成的环己烯形成配合物,稳定生成的环己烯,抑制环己烯再吸附到催化剂表面并加氢生成环己烷。在ZnSO_4最佳浓度0.61 mol·L-1下对Ru-Zn催化剂预处理15 h,Ru-Zn催化剂中助剂Zn O可以与ZnSO_4完全反应生成(Zn(OH)2)3(ZnSO_4)(H_2O)盐,在该催化剂上25 min苯转化68.2%时环己烯选择性和收率分别为80.2%和54.7%。而且该催化剂具有良好的稳定性和重复使用性能。     

双核烷基咪唑过氧磷钨酸盐相转移催化剂合成及催化烯烃环氧化性能

合成并表征了一类双核长链烷基咪唑阳离子修饰的过氧磷钨杂多酸盐催化剂[Dnmin]1.5PW4O24,考察了催化剂在过氧化氢为氧源的烯烃环氧化反应中的催化活性.研究表明,这类催化剂在反应过程中表现出相转移催化现象,并具有较高的催化活性和选择性.其中,双核十二烷基咪唑杂多酸盐催化剂[D12min]1.5PW4O24的活性最佳,其环己烯转化率和环氧环己烷选择性分别达到97.7%和96.3%.催化剂在经过简单离心分离后可重复使用,重复使用4次后环己烯转化率和环氧环己烷选择性仍可分别达到72.4%和97.2%.催化剂[D12min]1.5PW4O24在其它几种烯烃的环氧化反应中均表现出相转移催化特性,且具有较高的催化活性.     

二乙醇胺作添加剂Ru-Zn催化剂上苯选择加氢制环己烯

采用共沉淀法制备了Ru-Zn催化剂,考察了二乙醇胺的添加对Ru-Zn催化剂上苯选择加氢制环己烯性能的影响,并采用N2物理吸附、透射电镜、X射线衍射、X射线荧光、傅里叶变换红外和程序升温还原等手段对催化剂进行了表征.结果表明,二乙醇胺可以与浆液中ZnSO4反应生成(Zn(OH)2)3(ZnSO4)(H2O)3和硫酸二乙醇胺盐.随着二乙醇胺用量的增加,化学吸附在催化剂表面的(Zn(OH)2)3(ZnSO4)(H2O)3增多,它与硫酸二乙醇胺盐的协同作用提高了Ru-Zn(4.9%)催化剂上苯选择加氢生成环己烯的选择性.当二乙醇胺用量为0.3g时,(Zn(OH)2)3(ZnSO4)(H2O)3在Ru-Zn(4.9%)催化剂加氢后样品的表面高度分散,反应性能最佳,循环使用第3次时苯转化率为84.3%,环己烯选择性和收率分别达75.5%和63.6%;使用至第4次时,反应25min时苯转化率和环己烯选择性仍可达75%以上,环己烯收率为58%以上.     

助剂Fe和反应修饰剂修饰的Ru催化剂上苯选择加氢制环己烯

共沉淀法制备了Ru-Fe(x)催化剂,并利用X射线衍射(XRD)、X射线荧光光谱(XRF)、N2物理吸附和透射电镜等手段对催化剂进行了表征.结果表明,Ru-Fe(x)催化剂中助剂Fe以Fe3O4形式存在.单独Fe3O4并不能提高Ru催化剂的环己烯选择性.但在加氢过程中Fe3O4可与反应修饰剂ZnSO4反应生成(Zn(OH)2)3(ZnSO4)(H2O)x(x=1 or 3).化学吸附的(Zn(OH)2)3(ZnSO4)(H2O)x(x=1 or 3)在提高Ru催化剂环己烯选择性中起着关键作用.此外,Ru-Fe(x)催化剂的性能还与浆液中的Zn2+浓度和pH值有关.在0.61 mol/L ZnSO4溶液中Ru-Fe(0.47)催化剂不但给出了56.7%的环己烯收率,而且具有良好的稳定性和重复使用性能.化学吸附在Ru表面的Fe2+同样能提高Ru催化剂的环己烯选择性.在0.29 mol/L和0.61 mol/L FeSO4溶液中Ru-Fe(0.47)催化剂上化学吸附Fe2+量近似,性能近似.因为Fe2+和Zn2+性质的差异,在0.29 mol/L和0.61 mol/L FeSO4溶液中Ru-Fe(0.47)催化剂的环己烯选择性分别低于在同浓度的ZnSO4溶液中的.     

Carbonylation of cyclohexene to 2-cyclohexene-1-one by montmorillonite-supported Co(II) catalysts

A novel environmentally-friendly catalytic system for the carbonylation of cyclohexene with molecular oxygen under conditions of mild temperature, and under an atmospheric oxygen pressure is presented. In this system, a series of readily-prepared cobalt complexes of 2-aminophenol and its derivatives immobilised onto montmorillonite were used as catalysts. The catalysts were characterised by FT-IR, elemental analysis, thermogravimetric analysis, powder X-ray diffraction, diffuse reflectance ultraviolet visible spectra, scanning electron microscopic measurements, transmission electron microscopic measurements and the Brunauer-Emmett-Teller method. The effects of various reaction conditions such as catalyst dosage, temperature and time were optimised, obtaining an 88.7% conversion with 72.0% selectivity of 2-cyclohexene-1-one in 6 h. The results show that the catalytic activity of the cobalt complexes encapsulated in montmorillonite is higher than those of the free complexes. In addition, the heterogeneous catalysts were stable and can be recycled up to five times without any noticeable change in the catalytic activity.     

Preparation of nano-CuO-loaded halloysite nanotubes with high catalytic activity for selective oxidation of cyclohexene

A facile preparation method of nano-CuO catalysts, assembled in the hollow nanotube of halloysite nanotubes(HNTs), was developed. The characterizations of XRD, TEM, SEM, BET, XRF and FT-IR were used to analyze the structure and properties of the nano-CuO/HNT loaded catalyst. The XRD patterns indicated that the CuO nanoparticles on HNTs were monoclinic phase. The TEM-EDX and SEM images confirmed that most of nano-CuO catalysts with the crystal size of ca. 20 nm were assembled into the hollow nanotube of HNTs. The catalytic performance of the nano-CuO/HNT catalysts was evaluated by using selective oxidation of cyclohexene. The reaction temperature and recycling times were investigated. The results reveal that the nano-CuO/HNT catalysts exhibit an excellent catalytic oxidation performance for selective oxidation of cyclohexene to 2-cyclohexene-1-one.     

溴化锌-离子液体复合催化体系高效催化合成环状碳酸酯

随着全球“温室效应”和能源危机的加剧,用CO2作为某些化学品的Cl起始原料,既经济、安全,又能降低CO2对环境的危害,由于CO2的性质极不活泼,在固定CO2的反应中最典型的一个催化过程就是利用CO2和环氧化合物通过环加成反应合成环状碳酸酯：     

BDIE·[Zn-Al]催化二氧化碳与氧化环己烯共聚

在α-二亚胺型催化剂BDIE.[Zn-Al]催化下采用新的工艺进行CO2与氧化环己烯共聚反应,催化效率得到较大地提高.这些新的工艺包括在反应前用与催化剂摩尔比为1.5∶1的氧化环已烯进行数小时陈化;采用二氧化碳与氧化环已烯分批加料的聚合工艺.在25℃温度下陈化4 h,采用分批加料的方式反应,BDIE.[Zn-Al]的催化效率提高到69.9 g/g.     

Oxidation of p-chlorotoluene and cyclohexene catalysed by polymer-anchored oxovanadium(IV) and copper(II) complexes of amino acid derived tridentate ligands

3-Formylsalicylic acid (Hfsal), covalently bound to chloromethylated polystyrene (PS) and cross-linked with 5% divinylbenzene reacts with d,l-alanine and l-isoleucine to give the Schiff-base tridentate ligands PS-H(2)fsal-d,l-Ala and PS-H(2)fsal-l-Ile, respectively. These anchored ligands upon reaction with VOSO(4) and Cu(CH(3)COO)(2).H(2)O form the complexes PS-[VO(fsal-d,l-Ala)(H(2)O)], PS-[Cu(fsal-d,l-Ala)(H(2)O)], PS-[VO(fsal-l-Ile)(H(2)O)] and PS-[Cu(fsal-l-Ile)(H(2)O)]. The structures of these immobilized complexes have been established on the basis of scanning electron micrographs, spectroscopic (infrared, electronic and EPR), thermogravimetric and elemental analysis studies. The oxidation of p-chlorotoluene and cyclohexene has been investigated using these complexes as the catalysts in the presence of H(2)O(2) as the oxidant. Reaction conditions have been optimised by considering the concentration of the oxidant, the amount of catalyst used and the temperature of the reaction mixture. Under the optimised conditions, p-chlorotoluene gave a maximum of 14% conversion using PS-[VO(fsal-d,l-Ala)(H(2)O)] as the catalyst, with the main products having a selectivity order of: p-chlorobenzaldehyde > p-chlorobenzylalcohol > p-chlorobenzoic acid > 2-methyl-5-chlorophenol > 3-methyl-6-chlorophenol. The oxidation of cyclohexene with PS-[VO(fsal-d,l-Ala)(H(2)O)] proceeds with 79% conversion, which is followed by PS-[VO(fsal-l-Ile)(H(2)O)] with 77% conversion, and the oxidation of cyclohexene by Cu-based catalysts occurs with considerably lower conversions (29-32%). The selectivity of the products follows the order: 2-cyclohexene-1-ol > cyclohexene oxide > cyclohexane-1,2-diol > 2-cyclohexene-1-one. Recycling studies indicate that these catalysts can be reused at least three times without any significant loss in their catalytic potential. However, EPR studies indicate that while the polymer supported V(iv)O-complexes do not change after being used, the EPR spectra of the Cu-complexes show significant changes. The corresponding non-polymer bound complexes [VO(fsal-d,l-Ala)(H(2)O)], [Cu(fsal-d,l-Ala)(H(2)O)], [VO(fsal-l-Ile)(H(2)O)] and [Cu(fsal-l-Ile)(H(2)O)] have also been prepared in order to compare their spectral properties and catalytic activities. The non-polymer bound complexes exhibit lower conversion, along with lower turn-over frequency as compared to their polymer-bound analogues. Several EPR, (51)V NMR and UV-vis studies have been undertaken to detect the intermediate species, and outlines for the mechanisms of the catalytic reactions are proposed.     

双二茂铁基醛亚胺钼（ＶＩ）配合物的合成及催化性能

通过二茂铁甲醛与丙二胺反应得到双二茂铁基醛亚胺配体N~1,N~3-双二茂铁亚甲基丙烷-1, 3-二胺(FcMP), FcMP与MoO_2Cl_2(THF)_2的四氢呋喃溶液作用, 合成了双二茂铁基醛亚胺钼(VI)配合物. 以配合物为催化剂, 叔丁基过氧化氢为氧化剂, 分别以苯乙烯和环己烯为底物, 考察了温度、时间、催化剂量及溶剂对于烯烃均相环氧化反应的催化性能的影响. 结果表明, 在最优实验条件下, 反应12 h, 环己烯的转化率为88%, 环氧环己烷的选择性为98%;苯乙烯的转化率为84%, 氧化苯乙烯的选择性为76%. 催化剂经简单分离可回收使用, 且催化活性基本保持不变. 同时对环氧化反应的机理进行了初步探讨.     

Chemical fixation of CO2 with highly efficient ZnCl2/[BMIm]Br catalyst system

The chemical fixation of CO₂ with mono-substituted terminal epoxides or cyclohexene oxide to form cyclic carbonates under the ZnCl₂/[BMIm]Br catalyst system without using additional organic solvents was achieved in excellent selectivity (>98%) and TOF (5410 h⁻¹) and the catalyst could be used six times almost without losing its catalytic activity and selectivity. Besides, the pure cis-cyclic carbonate of cyclohexene oxide was obtained in this catalyst system.     

Chemical Fixation of CO2 with Highly Efficient ZnCl/[BMIm]Br Catalyst System

The search for environmentally benign and economic process has been the impetus for much of the research involving epoxide and carbon dioxide coupling in view of the so called "green chemistry" and" atom economy ", since CO2 is a renewable resource and can be used as a safe and cheap C 1 building block to synthesize useful organic compounds without producing any coproducts.[1-2] One of the most attractive synthetic goals starting from carbon dioxide is the chemical fixation of CO2 onto epoxide to afford the five-membered cyclic carbonates (Scheme 1),which are excellent aprotic polar solvents and are used extensively as intermediates in the production of pharmaceuticals and fine chemicals.[3] In the last decades of the twentieth century numerous catalytic systems have been developed for this transformation. While some advances have been obtained, all suffer from either low catalyst stability/reactivity, the need for co-solvent, or the requirement for high pressure and/or catalyst costing expensive.[4] Therefore, to find an effective,not exrensive, environmentally benign and economic catalyst system is urgent.In this paper, chemical fixation of CO2 with mono-substituted terminal epoxides or cyclohexene oxide to form cyclic carbonates under the ZnCl2/[BMIm]Br Catalyst System without using additional organic solvents was achieved in excellent selectivity (＞98%) and TOF(5410h-1) Besides,the pure cis-cyclic carbonate of cyclohexene oxide was obtained in this catalyst system.It was important to note that the catalyst could be recovered by simple vacuum distillation of the corresponding cyclic carbonates and could be used six times almost without losing its catalytic activity and selectivity. The catalyst system was found to be applicable to a variety of terminal epoxides and cyclohexene oxide, forming the corresponding cyclic carbonates in very high TOF and more than 98% selectivity. Based on the obtained results, we also propose the plausible mechanism for this chemical fixation reaction of CO2.