苯乙烯环氧化反应分子筛催化剂研究进展

综述了苯乙烯环氧化制取环氧苯乙烷的几种分子筛／H2O2催化体系，介绍了微孔分子筛（TS-1）、Ti-ZSM-5和Ti-ZSM-11分子筛介孔分子筛（MCM-41），β-钛硅分子筛、负载金属配合物的中孔分子筛及其在苯乙烯环氧化反应中的性能。     

杂多酸催化烯烃环氧化的研究进展

烯烃的环氧化物是应用最广泛的有机中间体,在有机合成反应中烯烃的环氧化反应占有十分重要位置。本文主要论述了以杂多酸作为催化剂,季铵盐作为相转移催化剂,以双氧水为氧化剂,在两相条件下催化烯烃环氧化的反应过程。     

Epoxidation of 1-hexene with hydrogen peroxide over nitrogen-incorporated TS-1 zeolite

Nitrogen-incorporated TS-1 zeolite (N-TS-1) was synthesized by direct calcining the as-synthesized TS-1 powder in NH₃ flow at high temperature. Epoxidation of 1-hexene with dilute H₂O₂ over N-TS-1 was studied. The results showed that the catalytic activity and selectivity of TS-1 were greatly improved upon post-synthetic nitridation. A new TiOOH intermediate with double hydrogen bonds was proposed. The new intermediate was more stable due to the presence of another hydrogen bond, which was formed between the stable nitrogen species and the H atom of the conventional five-member-ring intermediate, thereby improving the epoxidation activity.     

Phenol Hydroxylation over Alkaline Treated TS-1 Catalysts

Alkaline treatment on TS-1 can selective remove silica from the framework while MFI zeolitic framework remains intact, which creates new large micropores or even mesopores and increases Si/Ti ratio in the alkaline treated TS-1. Among various alkaline hydroxide, CsOH treatment leads to partial destruction of MFI structure. All the desilicated TS-1 samples show enhanced phenol conversion and dihydroxylbenzene (DHB) yield in acetone solvent by two folds, which can be attributed to the higher Ti/Si ratio and improved diffusivity. Pore structure modified with alkaline treatment affects significantly reaction pathway and product selectivity. The initial product over the parent TS-1 and NaOH treated TS-1 is mainly 4-hydroxycyclohexa-2,5-dienone and catechol enriched DHB, respectively.     

Preparation and Catalytic Performance in Propylene Epoxidation of Hydrophobic Hierarchical Porous TS-1 Zeolite

Catalysis Letters - The contribution introduced a new type of titanosilicate molecular sieve HTS-1-X with high specific surface area, high titanium content, hierarchical pores, hydrophobicity, and...     

芳烃精制脱烯烃分子筛催化剂的研究

本研究以铝胶、硅铝胶及钛铝胶为粘合剂,以HY分子筛为主要活性组分制备了芳烃脱烯烃分子筛催化剂.采用NH3-TPD、BET、TG和活性评价等方法对催化剂的酸性、脱烯烃活性、失活原因及再生性能进行了研究.结果表明,含有不同粘合剂的HY分子筛催化剂的脱烯烃活性均明显高于工业使用的NC-01颗粒白土催化剂,分子筛催化剂表面具有较多的弱酸中心是其性能良好的重要原因.积碳是分子筛催化剂表面失活的主要原因,经焙烧再生处理后分子筛催化剂仍具有较好的脱烯烃性能.经823 K焙烧的硅铝胶质量分数为20%的分子筛催化剂具有较佳的反应性能.     

Influence of Pt–Pd/TS-1 Catalyst Preparation on Epoxidation of Olefins with Hydrogen Peroxide

The catalytic performance of the platinum–palladium/titanium silicalite, which was a common catalyst for the direct epoxidation of olefins with hydrogen and oxygen, was tested by epoxidation of allyl chloride with hydrogen peroxide. The epoxidation capacity of the TS-1catalyst was reduced after loading palladium and platinum on it. Ti leaching and crystallinity decrease were observed by XRD and FT-IR. The decomposition of hydrogen peroxide was accelerated by the supported Pd and Pt. These contributed to the loss of epoxidation capacity of TS-1. Ti leaching and crystallinity decrease were probably main causes. We propose that the Ti leaching had the most important influence on the loss of epoxidation capacity     

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 …     

Styrene Epoxidation over Carbon Nanotube-Supported Gold Catalysts

Carbon nanotube supported gold catalysts prepared by deposition–precipitation with urea (DP urea) were characterized by various techniques. Its catalytic activity was examined for the oxidation of styrene using t-butylhydroperoxide as oxidant. This system showed good epoxide selectivity. The other factors, such as solvent, reaction time, concentrations of oxidant and catalyst, have also been investigated and reaction conditions are optimized. It is a novel highly active/selective and reusable heterogeneous catalyst for styrene epoxidation.     

A Simple and Convenient Method for Epoxidation of Olefins without Metal Catalysts

An easy method for epoxidation of olefins using bleach (sodium hypochlorite) and either a stoichiometric or catalytic amount of bromide ion has been developed. Without any transition metal catalyst a variety of non‐activated olefins give epoxides in high yields and good selectivity at ambient conditions.     

Epoxidation of Butadiene Over Nickel Modified TS-1 Catalyst

Abstract  

Nickel modified Titanium silicalite 1 (TS-1) catalysts provided an environmentally benign and effective method for butadiene epoxidation. Certain loading of modified Ni in our system significantly promoted TS-1 catalytic activity. The product vinyloxirane (VO) was obtained with high yield of 0.49 mol/L (theoretic equilibrium value 0.52 mol/L). The turnover number (TON, determined as the molar VO obtained per molar Ti atom) reached 1,140. Besides, the catalyst kept high activity during five runs of reusability test. XRD, N₂ adsorption and desorption, TPR, XPS, FT-IR and DR UV–Vis were employed to characterize the specific Ni role to Ti-site in Ni/TS-1 catalysts.     

Epoxidation of Cyclohexene over Crystalline and Amorphous Titanosilicate Catalysts

A microporous titanosilicate (TS-1) catalyst was synthesised from an amorphous titanosilicate precursor, and both the amorphous precursor and TS-1 were characterised by Ti K-edge X-ray absorption spectroscopy which revealed that Ti (IV) ions are in tetrahedral coordination in the calcined state. Each of these solids is catalytically active for the conversion of cyclohexene to cyclohexene oxide in the presence of H₂O₂. Use of urea–H₂O₂ adduct as oxidant increased the activity and selectivity for the formation of the epoxide with TS-1 as catalyst. However, a significant loss in catalytic activity is seen for the amorphous precursor.     

铁掺杂TS-1分子筛催化剂催化苯羟基化制备苯酚反应

本研究通过浸渍法制备了铁/TS-1系列催化剂,将制备的新型催化剂应用于苯直接羟基化制备苯酚的反应。研究了铁/TS-1催化剂的制备条件(煅烧温度,煅烧时间和铁的负载量)对催化活性的影响。考察了在不同的反应条件(反应时间,催化剂的量,H2O2的量)下铁/TS-1催化剂对苯羟基化制备苯酚的催化活性。在优化反应条件下得到苯的转化率为11.2%和苯酚的选择性为100%。     

水热法合成TS-1分子筛中的影响因素

有机物的选择性催化氧化是一类非常重要的化工反应。TS-1分子筛在这类反应中备受关注,其可与双氧水配合表现出优良的催化性能。本文分析了钛源、硅源、模板剂、晶化条件对TS-1分子筛纯度、结晶度及催化性能的影响,并对TS-1分子筛的发展方向提出了建议。     

ZSM—5型分子筛催化剂上的丙烷芳构化反应

本文重点讨论了经Ｚｎ、Ｇａ改性的ＺＳＭ－５催化剂的制备及其芳构化的性能,ＨＺＳＭ－５催化剂上丙烷芳构化的历程及Ｚｎ、Ｇａ对反应的影响。同时,分析了影响芳烃选择性的一些因素     

烯烃不对称环氧化反应研究进展

综述Salen-Mn配合物,手性酮,生物酶催化剂催化的不对称环氧化反应研究进展情况,详细介绍了酮催化剂的发展趋势。     

外环流气升式反应器中催化丙烯环氧化反应

本论文研究了外环流气升式反应器中TS-1催化丙烯环氧化反应,以单位催化剂空时收率为目标,进行了反应工艺条件的优化,考察了结构参数,上升管与下降管横截面积之比Ar Ad对反应的影响。     

TS-1分子筛在环己酮氨肟化反应中的应用

叙述了TS-1分子筛在环己酮氨肟化反应中的应用研究进展．阐述了国内外对环己酮氨肟化催化剂的研究概况及在工业化应用中所存在的问题,指出了TS-1分子筛在环己酮氨肟化反应中的应用研究主要集中在催化剂合成技术、分离和回收以及降低生产成本等方面。     

烯烃液相环氧化反应研究进展

从常用氧化剂无机过氧酸盐、过氧化氢、分子氧、有机过氧酸及烷基过氧化氢等方面，阐述了烯烃的环氧化方法，对环氧化用催化剂如Mo(Ⅵ）、V（V）、Ti（Ⅳ）络合物以及过渡金属卟啉络合物等进行了介绍。综述了由丙烯、环已烯等环氧化制备环氧丙烷和环氧环已烷等化合物研究进展以及环氧化用催化剂高分子固栽化研究情况，并对今后烯烃环氧化研究开发进行了展望。     

Synthesis of Hierarchical TS-1 Zeolite from Silanized Seeds

Hierarchical TS-1 zeolites with a bimodal pore architecture, consisting of the typical MFI micropores and an additional mesoporosity, have been synthesized by grafting an organosilane compound to the zeolitic seeds previously prepared from two different raw materials: a liquid gel and an amorphous SiO₂–TiO₂ xerogel. These hierarchical TS-1 zeolites show an excellent catalytic behavior in olefin epoxidation reactions employing organic hydroperoxides as oxidants due to the presence of the secondary mesoporosity, which makes possible the access and interaction of bulky molecules with the Ti active sites.