共查询到18条相似文献,搜索用时 57 毫秒
1.
2.
3.
4.
5.
环己烯的电化学环氧化研究 总被引:4,自引:0,他引:4
环己烯的电化学环氧化研究何俊翔,周锦成(温州师范学院化学系浙江温州325003)1前言环氧化合物是重要的试剂及有机化工合成中间体。对环氧化合物合成工艺的研究及产品开发应用具有一定的学术和经济价值。当今环氧化合物的有机合成路线通常采用烯烃与有机过氧化合... 相似文献
6.
V-MCM-41催化环己烯环氧化性能 总被引:1,自引:0,他引:1
采用水热法合成了V-MCM-41,并用ICP-AES、FTIR、DRS-UV-Vis、XRD、BET等技术对其进行了表征,发现只有部分V进入分子筛,所合成的V-MCM-41具有较高的结晶度,并且其结晶度随晶化液中V/Si摩尔比的增大而升高。V-MCM-41催化环己烯/H2O2氧化反应结果表明,当V-MCM-41中V含量大于1.10%(摩尔分数)时,骨架V-O-V物种在催化环己烯氧化反应的同时,也可加速H2O2的分解;乙腈是该反应体系的最佳溶剂,最佳反应温度为70℃。最佳反应结果表明,环己烯的单程转化率和H2O2有效利用率可分别达到23.91%和95.4%。 相似文献
7.
8.
采用一步法分别制备了一系列单金属介孔催化剂Ti-SBA-15-36,Mo-SBA-15-(180/28)和双金属介孔催化剂Mo-Ti-SBA-15-(X)。考察了双金属催化剂Mo-Ti-SBA-15-(X)的Mo含量,对催化剂的结构和催化性能的影响。分析了催化剂活性差异的原因以及探讨了双金属催化剂的催化协同机理。考察了催化环氧化反应中的主要影响因素。结果表明,最佳的双金属催化剂Mo-Ti-SBA-15-(180/28)的催化效果均优于单金属催化剂的环氧化效果。当反应时间为8 h,反应温度为80 ℃,催化剂剂量为25 mg,以环己烯作为底物,TBHP作为氧源,1,2-二氯乙烷作为溶剂时,Ti-SBA-15-36,Mo-SBA-15-(180/28)和Mo-Ti-SBA-15-(180/28)的转化率分别为41.07%、46.44%和98.33%,选择性分别为97.56%、93.19%和98.86%。同时Mo-Ti-SBA-15-(180/28)也具有很好的可循环利用性。 相似文献
9.
10.
11.
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。 相似文献
12.
对反应控制相转移催化剂制备方法进行了改进,催化剂产率可达94%,并用红外光谱(IR)和元素分析对催化剂进行了表征;将催化剂用于以w(H2O2)=34.5%为氧化剂,以质量分数76.7%的工业粗环己烯为原料合成环氧环己烷;探讨了反应时间、反应温度、环己烯与H2O2的摩尔比、催化剂用量、溶剂用量等因素对反应的影响。获得的较佳合成条件(以0.08 mol H2O2计)为:反应温度40℃,反应时间90 m in,催化剂用量0.6 g,n(C6H10)∶n(H2O2)=2.5∶1,溶剂1,2-二氯乙烷70 mL。该条件下环氧环己烷平均选择性为96.1%,环氧环己烷的平均收率达91.7%。将回收的催化剂用于反应,环氧环己烷的平均选择性和平均收率分别为95.3%和90.9%。 相似文献
13.
环己烯催化环氧化反应的研究新进展 总被引:1,自引:0,他引:1
综述了环己烯催化氧化法合成环氧环己烷的最新研究进展。近年来,催化环己烯环氧化越来越受到关注,因为它采用了来源方便和具有环保性质的氧化剂。介绍了环己烯催化环氧化的一些新进展。反应中采用了各种氧化剂如过氧化氢(双氧水),叔丁基过氧化氢(TBHP)和分子氧(O2),以及各种含有各种配体(如席夫碱、卟啉、酞菁和杂多酸)的过渡金属催化剂。对有关反应的机理进行了讨论。 相似文献
14.
Step-change experiments between H2, CO, and syngas mixtures with time resolution of ca. 0.3 s were undertaken to critically test mechanisms proposed in the literature for the Fischer-Tropsch synthesis. A silica-supported cobalt catalyst was used. Results suggest C2+ olefins and branched paraffins form from a carbon deposit on the catalyst surface. Two pathways appear to exist for methane formation. The first of these is from the carbon deposit through direct hydrogenation and through hydrogenolysis of the long-chain materials formed. The second pathway is hydrogenation of strongly adsorbed CO. 相似文献
15.
A catalyst for the copolymerization of CO2 and cyclohexene oxide was prepared by using acetylacetone and 4,4′‐methylenedianiline. The catalyst was characterized as composed of a novel structure of the polymeric diimide Zn complex. The catalyst tended to produce an alternative copolymer with efficiency as high as 128 g polymer/g of catalyst. The obtained copolymers were characterized by IR and NMR. Effects of reaction conditions such as reaction time and temperature, CO2 pressure, and catalyst concentration on copolymerization were investigated. Best results were obtained from the reaction at 90°C for 24 h, with catalyst concentration of 0.13 g/mL, and CO2 pressure of 2–3 MPa. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1123–1128, 2003 相似文献
16.
17.
Different cycling strategies are explored to see if carbon chain growth can be enhanced and methane formation suppressed. Of the strategies considered, bang-bang cycling between H2 and CO feeds substantially increased the consumption of CO and H2, but the formation of higher hydrocarbons and olefins was reduced. The best strategy for longer chain hydrocarbons suitable for jet or diesel fuels was found to be cycling between syngas mixtures. None of the cycling strategies was able to produce C8+ or low-molar mass olefin yields that matched yields found in steady-state operation. 相似文献
18.
Epoxidation of propylene by air over modified silver catalyst 总被引:14,自引:0,他引:14
Epoxidation of C3H6 to C3H6O by air was studied over a silver catalyst modified with alkali or alkaline earth chloride salts. The catalyst preparation
factors and the operational conditions could affect obviously the catalytic epoxidation property of the silver catalyst. It
was shown that, as a promoter of the silver catalyst, NaCl or BaCl2 is more suitable than LiCl or NH4Cl. The loading of NaCl should be controlled at about 3.8 wt%. Using a feed gas of 10% C3H6/air at a space velocity of 1.75×104 h−1, 18.6% C3H6 conversion and 33.4% selectivity to C3H6O were obtained at 350°C. Using a feed gas of 5% C3H6/air at a space velocity of 2.4×104 h−1, 54.0% C3H6 conversion and 26.3% selectivity to C3H6O were obtained at 390°C.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献