低钠条件下MCM-22分子筛的动态合成及其在甲烷无氧芳构化中的催化性能

由于 MCM- 2 2分子筛 [1] 具有独特的结构性质 ,故在许多烃类转化反应中已表现出突出的催化特性 [2～ 4 ] .我们在甲烷无氧芳构化的前期工作中发现 [5] ,酸性适当 ,具有交叉孔道且孔径与苯的动力学直径 (～ 0 .6nm)相当的分子筛载体活性较高 .MCM- 2 2的酸性与 ZSM- 5相当 [6 ,7] ,且拥有两套互不相通的多维孔道体系 [8] ,一套为二维正弦孔道 ,有效孔径为十元环 ( 0 .4nm× 0 .59nm) ;另一套亦为十元环孔道体系 ( 0 .4nm× 0 .54nm) ,但含有内径为十二元环的超笼 ( 0 .71 nm× 0 .71 nm× 1 .82 nm) .因此 ,以 MCM- 2 2为载体的催化剂…     

新型甲烷无氧芳构化催化剂MoO3/MCM-49

自Ｂｅｎｎｅｔｔ[1]等合成出新型分子筛ＭＣＭ 4 9以来 ,有关其结构及性质研究的报道相对较少 .Ｂｅｎ ｎｅｔｔ[1]指出 ,ＭＣＭ 4 9在一些特殊的催化反应上表现出了比ＭＣＭ 2 2更高的活性 (如在丙烯无氧芳构化反应中 ,ＭＣＭ 4 9上丙烯的转化率为 7 1 6% ,远大于ＭＣＭ 2 2的 2 64% ) .ＭＣＭ 4 9的发现时间较晚 ,且合成相对困难 ,在一定程度上限制了对其性质的进一步研究 .对甲烷无氧芳构化催化反应的研究发现 ,酸性适当且具有交叉十元环孔道体系的分子筛载体表现出了较高的催化活性 .ＭＣＭ 4 9与ＭＣＭ 2 2均具有两套互不相通的交叉…     

Vilsmeier试剂近年来在有机合成中的应用

Vilsmeier试剂是有机化学中很重要的一类试剂,用途很广。本文综述了Vilsmeier试剂近年来在有机合成中的应用     

Total synthesis of (±)-hibiscone C

A total synthesis of (±)-hibiscone C, one member of the furanosteroid family of natural products that also includes viridin and wortmannin, is reported. Two new pathways for formation of the key diacyl furan subunit are described.     

Diels–Alder/Oxidative Aromatization Approach towards the All‐Carbon DEF Tricyclic Skeleton of Daphenylline

Daphenylline is a recently isolated Daphniphyllum alkaloid with an unprecedented novel hexacyclic scaffold. In this study, the synthesis of the fused all‐carbon DEF tricyclic skeleton of daphenylline has been accomplished. Key steps of the reported sequence involve Evans asymmetric allylation, aldol condensation, Diels–Alder reaction, and oxidative aromatization reactions. The developed strategy might lead to the total synthesis of daphenylline.     

Thermogravimetric analysis of coke formation on plasma treated Mo-Fe/HZSM-5 catalyst during non-oxidative aromatization of methane

Summary Thermogravimetric (TG) analysis confirms that glow discharge plasma treatment has a remarkable influence on coke formation during the non-oxidative aromatization of methane over a Mo-Fe/HZSM-5 catalyst. The plasma treatment favors formation of active carbon species for methane aromatization.</o:p>     

Fluorinated <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">n</Emphasis> type copolyfluorene as polymer electret for stable nonvolatile organic transistor memory device

In this study, a kind of fluorinated copolyfluorene, named poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt-(2,3,5,6-tetrafluoro-1,4-phenylene)] (PODPF-TFP), is synthesized by facile palladium-based direct aromatization. Compared to the non-fluorinated counterpart, poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt-(p-phenylene)] (PODPF-P), deeper HOMO/LUMO energy level combined with steric hindrance effect endow PODPF-TFP with excellent spectra and morphology stability. Finally, organic field-effect transistor (OFET) memory devices are fabricated with PODPF-P/PODPFTFP as the dielectric layers, and they both exhibit flash type storage characteristic. Owing to the electronegativity of fluorine atom, the device based on PODPF-TFP exhibits larger memory window and more stable I _on/I _off ratio during a retention time of 10⁴ s as well as a better aging stability. The present study suggests that fluorinated p-n copolyfluorene electrets could enhance the capabilities of charge trapping and storage, which are promising for OFET memory devices.     

Formation of Thermally Robust Frustrated Lewis Pairs by Electrocyclic Ring Closure Reactions

The phosphorus/boron‐substituted hexatriene systems 6 undergo thermally induced electrocyclic ring closure to yield the cyclohexadiene‐derived P/B frustrated Lewis pairs (FLPs) 7 . Subsequent TEMPO oxidation gives the phenylene‐bridged FLPs 8 . Both systems activate dihydrogen and the thermally robust FLPs undergo carbon–carbon coupling reactions at a mesityl group upon treatment with dimethyl acetylenedicarboxylate at elevated temperatures.     

生物质衍生物γ-戊内酯催化转化制芳烃和2-环戊烯酮的研究

应用浸渍法在ZSM-5沸石分子筛孔道中引入过渡金属Zn物种,制备了具有不同Zn含量的Zn/ZSM-5。考察了反应温度、催化剂用量、催化剂的酸性性质等条件对γ-戊内酯芳构化产物组成(气、液、固产物)及其液体成分含量的影响。实验结果表明,ZSM-5分子筛孔道中引入Zn后,可以有效改变液体产物成分以及影响气体和固体产物收率。当ZSM-5分子筛孔道中引入Zn物种后,能够明显提高液体产物中苯、甲苯、乙苯、萘等芳香类化合物的含量,表明Zn物种能促进γ-戊内酯芳构化反应的进行。     

Convenient synthesis of 5-aryl(alkyl)sulfanyl-1,10-phenanthrolines from 5,6-epoxy-5,6-dihydro-1,10-phenanthroline, and their activity towards fungal β-d-glycosidases

A broad series of novel 5-aryl(alkyl)sulfanyl-1,10-phenanthrolines has been prepared by a new simple procedure: a treatment of the commercially available 5,6-epoxy-5,6-dihydro-1,10-phenanthroline with various thiols in the presence of a base. Other functional groups attached to the thiol allow a use of the products as building blocks in synthesis of versatile ligands and in functionalization of surfaces. The synthesized phenanthrolines showed a moderate ability as activators or inhibitors of fungal β-d-glucosidases and β-d-galactosidases.