环戊烯催化氧化合成戊二醛

以环戊烯为原料 ,采用钨酸催化剂合成戊二醛。用GH沉淀剂回收钨酸催化剂 ,同时将反应中间体进一步转化成戊二醛。确定了较佳合成工艺条件 :n(H2 O2 )∶n(C5H8) =(2 .0 0～ 2 .0 5 )∶1 0 0 ,m(H2 WO4 )∶m(C5H8) =(0 .0 4～ 0 .0 5 )∶1 0 0 ,n(GH)∶n(H2 WO4 ) =(1.0 5～ 1.10 )∶1 0 0 ,沉淀反应时间 6～ 7h。戊二醛总收率 6 5 %以上。     

环戊烯催化氧化合成戊二醛

介绍了以50％的H2O2为氧化剂，钨酸为催化剂，经环戊烯路线合成戊二醛的研究情况，研究结果表明了此氧化反应不能在基介质中进行，在反应温度40摄氏度，常压等较温和的条件下，产品收率达59％以上。     

WO_3/HMS催化剂多相催化氧化环戊烯合成戊二醛

以(NH4)2WO4为钨源制备的WO3/HMS分子筛为催化剂,过氧化氢为氧化剂,考察了在环戊烯氧化制备戊二醛的多相催化反应中反应时间、反应温度、催化剂质量、溶剂用量和氧化剂质量分数等因素对戊二醛收率的影响。筛选出WO3/HMS催化环戊烯(CPE)合成戊二醛反应的适宜工艺条件:n(H2O2)∶n(W)∶n(CPE)=2∶0.025∶1,V(t-BuOH)∶V(CPE)=8∶1,反应温度为35℃,反应时间为30 h。戊二醛的收率可达67%。     

环戊烯催化氧化合成戊二醛的研究进展

综述了以环戊烯为原料氧化合成戊二醛的各种方法,对各种催化氧化方法进行了分析、评述,总结了适合于工业化生产的方法。     

环戊烯催化氧化合成戊二醛的研究

对环戊烯催化氧化合成戊二醛的工艺进行了研究,考查了影响反应的主要因素,摸索出最佳工艺路线：在叔丁醇溶剂中,以钨酸与硼酐（质量比为1：1）为催化剂,双氧水为氧化剂,反应时间为4h,温度为35℃,戊二醛的收率约为46％。     

环戊烯催化氧化合成戊二醛及其动力学

对在非水溶剂存在下过氧化氢一步催化氧化环戊烯制备戊二醛过程中的催化体系进行了研究。考察了具有脱水功能的Ｂ２Ｏ３的作用及用量，确立了具有优良催化性能的催化体系ＷＯ３－Ｂ２Ｏ３；实验测定了反应动力学数据，采用非线性回归Ｐｏｗｅｌ共扼法求得了反应动力学方程。在推荐的催化剂体系和工艺条件下，环戊烯转化率６７％，戊二醛收率６３％，选择性９１％。     

凹凸棒粘土负载WO3催化剂用于环戊烯环氧化反应

以凹凸棒粘土（AT）为载体,钨酸铵为钨源,通过浸渍法制备了WO3/AT催化剂,采用FT-IR和XRD对其进行了表征,其后以30%（质量分数）H2O2为氧源、叔丁醇（TBA）为溶剂研究了其在环戊烯（CPE）环氧化反应中的催化性能。试验结果表明,WO3均匀地分散于凹凸棒粘土载体表面;在V[30%（质量分数）H2O2]/V（CPE）=2.2,V（TBA）/V（CPE）=10的条件下,环氧化反应的适宜工艺条件为：反应温度为308 K、反应时间为24 h、催化剂用量为0.3 g/mL（CPE）、WO3负载量为40.0%（质量分数）、催化剂焙烧温度为823 K和焙烧时间为2 h,在此条件下,环戊烯环氧化物（CPO）的收率为40.2%,CPE的转化率为92.1%。该催化剂对CPE的环氧化反应展现了较好的催化活性。     

新型钨基催化剂上环己烯环氧化反应

烯烃环氧化在现代化学中具有重要的学术和工业价值,但采用绿色氧化剂过氧化氢仍面临传质的挑战。采用过氧缩合法制备了一种新型钨基催化剂,用于过氧化氢与环己烯环氧化研究,环己烯的转化率为51.2%,环氧环己烷的选择性为69.2%。结果显示该催化剂催化活性高,环氧环己烷的选择性好,反应条件温和,工艺无溶剂且绿色环保。     

氨改性的介孔二氧化硅的直接合成和CO2吸附

Amine-functionalized mesoporous silica was prepared by using lauric acid and N-stearoyl-l-glutamic acid as structure directing agents via the SN+-I mechanism and applied to CO2 adsorption at room temperature. With γ-aminopropyltriethoxysilane as co-structure directing agent and due to the direct electrostatic interaction with anionic surfactant, most of the amino groups were uniformly distributed at the inner surface of pores and the performance was stable. The amine-functionalized mesoporous silica was characterized by Fourier transform infrared spectrometer, X-ray diffraction, nitrogen physisorption and thermogravimetric analysis. The CO2 adsorption capacity was measured by digital recording balance. At the room temperature and under the atmospheric pres-sure, the adsorption capacity of LAA-AMS-0.2 for CO2 and N2 is 1.40 mmol•g1 and 0.03 mmol•g1, respectively, indicating high separation coefficient of CO2/N2.     

微波促进环戊烯氧化合成戊二酸

以质量分数为30％的H2O2作氧化剂,磷钨酸作催化剂,通过均匀实验,考察了微波条件下环戊烯催化氧化合成戊二酸的活性。结果表明,在微波条件下,磷钨酸在环戊烯氧化合成戊二酸的过程中显示了较高的催化活性,最佳反应条件为：n（环戊烯）：一（磷钨酸）：n（30％H2O2）=56．5：0．3：227．9,先在75℃条件下回流反应1h,然后在微波条件400W,90℃,反应50min,戊二酸的收率可达61．37％。此外,还研究了磷钨酸盐催化环戊烯氧化合成戊二酸的活性。     

过氧酸条件下催化环戊烯氧化制备戊二醛的工艺研究

以环戊烯（CPE）为原料、在甲酸与过氧化氢形成的过氧甲酸体系中,以铌酸为催化剂一步合成戊二醛,考察了反应物配比、催化剂用量、反应温度、反应时间等对反应的影响。在最佳反应条件下,戊二醛的收率达到65％。该方法反应条件温和、高效节能,具有较好的工业化价值。     

环戊烯氧化制戊二酸相转移催化剂的制备

以过氧化氢为氧化剂,采用反应控制相转移催化剂催化环戊烯选择氧化制备戊二酸,考察催化剂制备工艺、催化剂用量及反应物料配比对催化剂收率和催化剂性能的影响。结果表明,溶解钨酸最佳过氧化氢浓度为25%,n(钨酸)∶n(过氧化氢)=1∶10,75℃溶解50 min,催化剂制备过程中最佳溶剂为水,而整个制备体系中最好不使用任何有机溶剂,在催化剂最佳使用量为环戊烯质量的10%和n(过氧化氢)∶n(环戊烯)=4.15∶1条件下,戊二酸收率为95.6%。     

二元羧酸为配体制备的钨钼复合物催化氧化环戊烯

通过引入不同的二元羧酸（草酸、丙二酸和酒石酸）作为配体制备出各种钨和钼复合物,并采用元素分析、FT-IR和TG-DSC表征手段测定钨钼复合物的化学组成,探讨了复合物的存在形式。当含钨复合物用于催化氧化环戊烯时,草酸和丙二酸为配体制备的含钨复合物催化氧化环戊烯,产物环戊烯环氧化物的收率分别为53.41%和80.91%;当以草酸、丙二酸和酒石酸为配体时,制备的含钼复合物为催化剂催化氧化环戊烯（CPE）,产物环戊烯环氧化物(CPO)的收率分别为72.30%、69.59%和16.44%。     

戊二醛的合成及应用

本文介绍了戊二醛的各种合成方法,对吡啶法、丙烯醛法、戊二醇法、戊二酸法及环戊烯法等主要合成方法进行了评述,分析了其优缺点,介绍了戊二醛在消毒灭菌、皮革制品、石油开采等方面的应用情况。     

环戊烯在Au-SBA-15催化剂上选择性氧化

在不添加任何助剂的条件下，将合成的Au-SBA-15介孔分子筛催化剂用于催化环戊烯液相氧化反应。探讨了反应时间、反应温度和反应压力等因素对反应的影响。结果表明，在反应时间5 h、反应温度353 K和反应压力2.5 MPa条件下，环戊烯转化率可达8.6％，环戊酮选择性达90.2％，催化剂重复使用4次，其活性基本保持不变。     

Phenyl modification of Mn‐containing mesoporous silica and catalytic oxidation of toluene

BACKGROUND: Catalytic oxidation of toluene with dioxygen is a fundamental industrial technology because the oxidized products are important intermediates for many fine chemicals. In this study, phenyl modification was utilized to alter catalyst surface characteristics in order to enhance activity. RESULTS: Phenyl groups were successfully immobilized on the surface of Mn‐containing hexagonal mesoporous silica (HMS) through a one‐step synthesis route, as demonstrated by detailed characterization. As a result, the surface of the catalyst Ph? Mn? HMS was more hydrophobic with a water droplet contact angle of 96°. In the oxidation of toluene to benzoic acid with dioxygen under solvent‐free conditions, this new catalyst showed higher activity and selectivity than non‐organomodified Mn? HMS, and the conversion and selectivity increased by a factor of 40% and 9%, respectively. CONCLUSION: Modification of the catalyst surface with phenyl groups was an effective strategy to increase activity in the oxidation of toluene. Both conversion and selectivity were improved and this is linked to the hydrophobic character of the surface. This organic modification strategy may also be extended for oxidation of other hydrocarbons. Copyright © 2009 Society of Chemical Industry     

Highly selective gas-phase oxidation of benzyl alcohol to benzaldehyde over silver-containing hexagonal mesoporous silica

Silver-containing hexagonal mesoporous silica (Ag-HMS) catalysts with different Si/Ag ratios were synthesized by one-pot hydrothermal method for gas-phase selective oxidation of benzyl alcohol to benzaldehyde. The samples were characterized by nitrogen adsorption, X-ray diffraction, scanning electron micrograph, transmission electron micrograph, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectra. It was found that the Ag-HMS catalysts with different Ag loadings (0.55-3.50 wt.%) and different Ag particle sizes (5-32 nm) showed a similar level of catalytic property because they possess a similar Ag surface area. The Ag-HMS catalyst with a Ag loading of 2.81 wt.% exhibited excellent catalytic properties at 583 K with a high benzyl alcohol conversion of near 100%, benzaldehyde selectivity of around 96.0%, and benzaldehyde yield of about 96.0%, superior to those of other M-HMS catalysts (M = Co, Ce, La, Cu, Sr, Cd, Ni, Mn, V, and Fe). The enhanced catalytic performance could be attributed to the presence of the Ag surface oxygen species generated via oxygen spillover process. The work would be helpful for the development of novel Ag catalysts for selective oxidation of benzyl alcohol to obtain high quality of benzaldehyde and understanding the catalytic mechanism.     

Catalytic oxidation of cyclopentene to glutaraldehyde over WO3/Ti–HMS catalyst

A PdZn alloy-based catalyst was prepared by impregnation with a Pd salt of the oxides obtained by the thermal decomposition of a Zn–Al hydrotalcite. Two samples were obtained by carrying out the reduction at 373 and 673 K, that were characterized by chemical analysis, powder XRD and TEM. The catalytic activity was tested in the low pressure hydrogenation of acetophenone. The results were compared with those obtained using a conventional palladium catalyst.