苯乙烯环氧化反应金属配合物催化剂研究进展

介绍了国内外常用于苯乙烯环氧化反应的金属配合物催化剂,并对其研究概况、及对产率和转化率的影响作了简要介绍。     

MCM-41介孔分子筛改性研究进展

介绍了有序介孔材料的定义和分类,MCM-41介孔分子筛、合成方法和形成机理,针对其MCM-41目前存在的一些问题,综述了国内外对MCM-41介孔分子筛最新的改性研究进展。     

超微粒介孔分子筛Ti-MCM-41的制备及苯乙烯催化氧化的研究

在强酸性条件下，在60℃水浴中，以无水乙醇和异丙醇为混合溶剂，合成了nSi)：n(Ti)分子比为30的超微粒介孔分子筛蜀-MCM-41。在超微粒介孔分子筛Ti-MCM-41和H2O2作用下，对苯乙烯进行催化氧化的反应，其产物是苯乙酮和苯甲醛，并且考察了分子筛Ti-MCM-41不同用量、H2O2和苯乙烯不同分子比、反应时间及反应温度对苯乙烯转化率的影响。实验结果表明，在苯乙烯催化氧化反应中，反应的最佳温度为60℃，最佳时间是10h，最佳分子筛用量是0．6g，n(H2O2)：n(苯乙烯)分子最佳比是4：1。由于H2O2氧化后的产物是H2O2，因此，这种清洁的方法是今后有机合成发展的趋势。     

介孔分子筛催化环己烯环氧化研究进展

综述了国内外对介孔分子筛催化环氧化环己烯的研究进展,主要包括金属离子掺杂、有机分子修饰、固载金属氧化物和金属络合物等方面.     

钛硅分子筛TS-1催化烯烃环氧化反应的研究进展

TS-1催化的烯烃环氧化反应具有条件温和、环境友好、符合绿色化学理念、应用前景广阔等优点.该文首先介绍了不同介质中TS-1催化过氧化氢(H2O2)氧化脂肪烯烃反应的进展,结果表明,在甲醇等质子溶剂中,溶剂可以和Ti—OOH(钛氧活性中心)通过氢键作用形成活性中间体,实现烯烃的环氧化;同时,TS-1的酸中心易引发环氧化物...     

介孔MCM—41分子筛水热稳定性的研究进展

综述了近年来关于各种增强介孔MCM-41分子筛水热稳定性的方法,分析比较了各种方法的特点,阐释了各种方法的作用机理,最后指出了提高分子筛水热稳定性的发展前景.     

负载型CTAB/MCM-41介孔分子筛的制备及其对溴代反应催化性能的研究

采用水热晶化法,以CTAB为模板剂合成出MCM-41介孔分子筛,后经过220℃低温焙烧4 h,可成功将CTAB固载于MCM-41,并对产物进行了XRD表征。将制备的CTAB/MCM-41催化剂用于1,7-庚二醇的溴代反应,通过对使用不同催化剂条件下反应速率的比较表明:CTAB/MCM-41的催化活性较好于未负载的CTAB。负载型的催化剂经多次使用后活性基本不变,并且能够简化反应后的分离步骤。     

HTS分子筛催化丙烯环氧化反应研究

中国石化石油化工科学研究院在传统水热合成TS-1分子筛的基础上,自主开发了TS-1分子筛重排改性工艺。该工艺具有制备重复性好的优点,经重排改眭后的TS-1分子筛晶粒具有空心结构（商品牌号为HTS）,催化苯酚羟基化反应的活性可提高2-4倍,催化环己酮氨肟化反应的活性亦有大幅度提高,且已成功应用于中国石化巴陵石化公司己内酰胺的工业化生产。     

MCM-41介孔分子筛研究进展

介绍了介孔材料的定义,总结了MCM-41介孔分子筛的合成方法,针对其目前存在的孔径较小及酸性较小的缺点,综述了国内外对MCM-41介孔分子筛的孔径扩大分的最新研究进展。     

用于氧化反应的改性介孔分子筛MCM-41研究进展

主要从金属掺杂、杂多酸负载和有机官能化等方面详细介绍了改性的MCM-41分子筛作为催化剂在氧化反应中的应用情况,分析了其优缺点。今后的研究重点将是进一步提高改性材料MCM-41分子筛的活性,解决活性组分溶脱现象以及水热稳定性等问题。     

酒石酸钛配合物在MCM-41上的组装和催化苯乙烯环氧化

采用表面模板组装途径合成了MCM-41介孔材料,研究了这类载体上键合钛酸异丙酯+酒石酸二乙酯(Ti(OiPr)4+DET)和TiCl4+DET两类钛配合物的组装方法。XRD和FT-IR分别被使用来表征载体的晶体结构和载体与钛配合物的键合作用,结果表明:MCM-41在焙烧过程中,其介孔长程有序结构会发生退化,这种结构退化将导致1219和580cm-1红外带的消失,并诱发载体产生强的Si-OH畸变振动。在催化苯乙烯环氧化反应中,用焙烧载体组装钛催化剂显示了最好的氧化活性;而用含模板剂载体组装钛催化剂则显示出最高的环氧化选择性。胺基模板剂和DET配体对钛活性中心的调变作用将造成其活性下降,而环氧选择性上升。     

Catalytic Epoxidation of Styrene by Molecular Oxygen over a Novel Catalyst of Copper Hydroxyphosphate Cu2(OH)PO4

Catalytic epoxidation of styrene by molecular oxygen over a novel copper hydroxyphosphate catalyst, Cu₂(OH)PO₄, was studied. Catalytic data show that the catalyst Cu₂(OH)PO₄ is very active, and the main products are benzaldehyde and styrene epoxide. Some important factors associated with the catalytic activity and selectivity have been investigated extensively.     

Propylene Epoxidation Over Silver Supported on Titanium Silicalite Zeolite

Epoxidation of propylene to propylene oxide over Ag/TS-1 in the presence of oxygen and hydrogen was carried out in a fixed-bed, quartz flow reactor. The effects of Ag loading, Si/Ti ratio of TS-1 and calcination temperature and calcination method of Ag/TS-1 on the propylene epoxidation were investigated. The results show that Ag loading, the calcination temperature and calcination method of Ag/TS-1 as well as the Si/Ti ratio of TS-1 have a great effect on the catalytic properties. The optimum Ag loading, calcination temperature and calcination method of Ag/TS-1 and Si/Ti ratio of TS-1 are 2 wt%, 450 °C in air and 64 respectively. Over 2.0 wt% Ag/TS-1(n_Si/n_Ti = 64) catalyst, at a space velocity of 3000 h^-1, 0.92% propylene conversion with 91.21% selectivity to propylene oxide is obtained at 150 °C. The deactivation of Ag/TS-1 catalyst is not due to the changes of active species, but because of the coke of the catalyst, which can be easily regenerated by calcination at 450 °C in air.     

硅烷化含钛介孔分子筛催化环己烯环氧化动力学

研究了气相沉积法制备的硅烷化含钛介孔分子筛(Ti/HMS)催化环己烯与异丙苯过氧化氢(CHP)的环氧化反应的宏观动力学.结果表明:环己烯与CHP的环氧化反应对催化剂的量表现为1级;对于环己烯和氧化剂CHP,随着浓度的增加,反应随之由1级向0级过渡,根据实验结果和反应机理,运用Rideal-Eley方法,提出了硅烷化Ti/HMS催化环己烯与CHP环氧化反应的动力学方程.     

不对称钴配合物的合成及其催化苯乙烯环氧化

将合成的N-取代的吡啶-2-醛亚胺制备成2∶1型不对称吡啶亚胺钴(Ⅱ)配合物(CoL2n,n=1,2…6),并通过红外光谱、元素分析、核磁共振氢谱、热重分析等对相关化合物进行表征。以分子氧为氧源,考察催化剂的种类、溶剂、反应温度、反应时间对苯乙烯环氧化反应性能的影响。研究表明,配合物CoL42是最有效的催化剂;配合物中亚氨氮上取代基的供电子性和空间位阻有利于提高配合物的催化活性;在优化的反应条件下,苯乙烯的转化率达99.9%,环氧苯乙烷的选择性为62.4%。     

Asymmetric Epoxidation of Styrene on the Heterogenized Chiral Salen Complexes Prepared from Organo-Functionalized Mesoporous Materials

Organosilane-modified mesoporous materials have been prepared under mild and acidic conditions by a solvent evaporation method using C₁₆TMABr surfactant as a template. The mesoporous samples synthesized in ethanol solvent by using this evaporation method showed a fully disordered pore system, but those obtained under hydrothermal conditions had highly ordered pores. The chiral salen Mn(III) complexes were immobilized on these organosilane-functionalized mesoporous silicas by a grafting method. The catalysts used in the asymmetric epoxidation of styrene and cis-stilbene and the effect of different mesoporous structures on the reactivity was investigated. Similar enantioselectivities were observed by using these heterogenized salen complexes as compared with reaction under homogeneous conditions.     

Vapor-Phase Epoxidation of Propene over Au/Ti-MCM-41 Catalysts: Influence of Ti Content and Au Content

Ti-MCM-41 samples were used for propene epoxidation using H₂ and O₂ after Au deposition by deposition--precipitation. Au nanoparticles supported on Ti-MCM-41 with Ti incorporated hydrothermally followed by post-synthesis grafting gave higher propene oxide yields than Ti-MCM-41 with Ti incorporated hydrothermally or by grafting. Au L₃-edge EXAFS spectra show the presence of metallic Au for the low Au content (0.21 wt%) catalyst which is more selective to epoxidation, while at high Au loadings (0.42 wt%) oxidic Au species are observed and the catalyst shows lower epoxide selectivity.     

Aerobic photochemical oxidation in mesoporous Ti-MCM-41: epoxidation of alkenes and oxidation of sulfides

Irradiation with visible light of a secondary alcohol, benzhydrol, in the presence of molecular oxygen within a titanium-substituted mesoporous molecular sieve, Ti-MCM-41, led to the formation of the α-hydroperoxoalcohol and then hydrogen peroxide. The peroxide species reacted in situ with alkenes and sulfides and led to the titanium center catalyzed selective formation of epoxides from alkenes and sulfoxides from sulfides. The cascade of reactions represents a new method for the photoactivation of oxygen in the presence of alcohols. This revised version was published online in July 2006 with corrections to the Cover Date.     

Catalytic Aerobic Epoxidation of Olefins by Nanostructured Amorphous CoO–MCM-41

Nanostructured amorphous cobalt oxide deposited inside the pores of MCM-41 using ultrasonic deposition--precipitation of cobalt tricarbonyl nitrosyl in decalin was found to be an efficient catalyst for the epoxidation of olefins under aerobic conditions.     

丙烯环氧化中TS-1寿命

钛硅催化剂 (ＴＳ - 1)催化下的丙烯与Ｈ2 Ｏ2 环氧化过程是环氧丙烷 (ＰＯ)洁净生产的发展方向[1,2 ] ,反应条件温和 ,选择性高 ,但目前的研究主要在催化剂制备 .虽然部分学者[3] 对催化剂的寿命进行了报道 ,但仅限于 5～ 8次间歇反应的累计结果 .本文根据动力学研究的结果[4 ,5] ,采用连续淤浆反应器 ,在最佳反应和加速反应条件下 ,对催化剂的寿命进行研究 ,测定了该催化剂的单程寿命 ,并用ＸＰＳ(Ｘ射线光电子能谱 )分析了催化剂失活的原因 ,为丙烯环氧化工艺的进一步工业化提供指导和依据 .实验中钛硅分子筛 (ＴＳ - 1)按文献 [2 ]合成 …