Ga2O3／HZSM—5催化剂的XRD,XPS和TPR研究

利用ＸＲＤ、ＸＰＳ、ＴＰＲ等技术对Ｇａ２Ｏ３／ＨＺＳＭ－５催化剂进行表征，结果表明，催化剂中镓组分以聚集态和分散态的形式存在，其中聚集态中α－Ｇａ２Ｏ３在一定条件下可转化为β－Ｇａ２Ｏ３；分散态又可分为游离Ｇａ２Ｏ３和与ＨＺＳＭ－５产生相互作用的镓组分，催化剂预处理条件及反应一再生过程对镓的分布及状态有较大影响。     

氟氯有机化合物对HZSM-5分子筛改性过程中氟和氯的作用

利用ＸＲＤ，ＭＡＳ，ＮＭＲ，ＩＲ和ＸＰＳ等手段研究了ＣＦ４－ｎＣｌｎ改性的ＨＺＳＭ－５分子筛的体相和表面结构的变化。结果表明，改性过程中Ｆ和Ｃｌ均能使ＨＺＳＭ－５脱铝和脱硅。Ｃｌ可以使沸石骨架ＳｉＯ２／Ａｌ２Ｏ３升高，而Ｆ除使沸石骨架脱铝外，还会极化其晶格。Ｆ比Ｃｌ更容易在沸石表面富集。Ｆ和Ｃｌ是通过取代Ｏ或ＯＨ与沸石表面Ｓｉ或Ａｌ作用的。改性后的沸石表面有数种含氟表面物种存在。     

MoO＿3／（TiO＿2－SiO＿2）催化剂的表面分散状态及催化性能的研究

用气相流动吸附法（ｇｒａｆｔｉｎｇ）制备复合载体，用浸渍法（ｉｍｐｒｅｇｎａｔｉｏｎ）制备ＭｏＯ３／（ＴｉＯ２－ＳｉＯ２）催化剂．应用ＬＲＳ和ＴＰＲ技术研究ＭｏＯ３在复合载体ＴｉＯ２－ＳｉＯ２表面的分散状态，发现ＴｉＯ２在ＳｉＯ２表面的分散可增强ＭｏＯ３与载体之间的相互作用，提高ＭｏＯ３在载体表面的分散阈值．催化剂的活性评价在固定床中压反应装置中进行，以６９％（ｗｔ）环己烷、２０％（ｗｔ）的环己烯、１０％（ｗｔ）的苯、１％（ｗｔ）的噻吩混合液为反应液，以噻吩、环己烯和苯的转化率作为催化剂的ＨＤＳ、ＨＹＤ、ＢＨＤ活性指标．结果表明，经ＴｉＯ２调变后，其ＨＤＳ、ＨＹＤ、ＢＨＤ活性都较原来高，对于不同ＭｏＯ３含量的ＭｏＯ３／（ＴｉＯ２－ＳｉＯ２），ＨＤＳ、ＨＹＤ催化性能测试发现，当ＭｏＯ３含量低于分散阈值时，其ＨＤＳ、ＨＹＤ活性随ＭｏＯ３含量线性上升，但在高于分散阈值后，几乎保持不变．该催化剂对苯几乎没有加氢活性，显示出很高的环己烯加氢选择性．通过分散阈值与其ＨＤＳ、ＨＹＤ活性的关系可知，分散阈值可作为优化加氢精制催化剂配比的一个重要参数，具有较强的实际意义     

Zn／HZSM－5分子筛上乙烯、乙烷芳构化的协同作用机理

运用ＮＨ＿３－ＴＰＤ、ＩＲ－ＯＨ、Ｐｙ－ＩＲ、ＣＯ－ＩＲ及ＸＰＳ等手段对Ｚｎ／ＨＺＳＭ－５及其浸碱催化剂的酸组分和金属组分构成的Ｌ酸性质进行了表征，考察了催化剂对乙烯、乙烷的芳构化作用．发现Ｚｎ／ＨＺＳＭ－５中形成了Ｚｎ￣（２＋）－Ｌ强酸中心，使分子筛的Ｂ酸中心减少．浸碱也可使分子筛的Ｂ酸减少，芳构化反应的活性和选择性均与Ｚｎ／ＨＺＳＭ－５的双中心Ｚｎ￣（２＋）－Ｌ酸和Ｂ酸的相互匹配密切相关，Ｂ酸和Ｌ酸存在最适合匹配，因此Ｚｎ／ＨＺＳＭ－５在乙烯、乙烷芳构化反应中存在最佳锌含量．     

苯羟基化为苯酚新型催化剂

首次介绍了一种以ＨＺＳＭ－５为载体，以Ｌａ２Ｏ３为促进剂，采用浸渍法制成的Ｆｅ２Ｏ３－Ｌａ２Ｏ３／ＨＺＳＭ－５新型催化剂，在常压，反应温度为３００℃条件下，以Ｈ２Ｏ２为氧化剂使苯羟基化为苯酚，取得了苯的最高转化率和苯酚的选择性分别达到４０．２％和９４．０％的结果。     

无机膜反应器对丙烷芳构化历程的影响

根据实验结果，从理论上分析了Ａｌ２Ｏ３无机膜反应器对ＨＺＳＭ－５，０．４％Ｇａ／ＨＺＳＭ－５和０．５％Ｐｔ－０．４％Ｇａ／ＨＺＳＭ－５催化剂上丙烷芳构化反应历程的影响。结果表明，氢气在烷烃活化、环烃形成芳烃和低碳烯烃加氢过程中担当着重要角色，膜反应器通过影响这些步骤，进而影响整个芳构化反应的选择性。     

环己酮肟在改性氧化锆催化剂上的Beckmann重排反应Ⅲ．B_2O_3对ZrO_2的改性效应

采用ＩＲ和ＸＲＤ技术研究了Ｂ２Ｏ３／ＺｒＯ２催化剂的结构性质，用ＩＣＰ－ＭＳ测定了样品中Ｂ２Ｏ３的含量，通过Ｈａｍｍｅｔ指示剂正丁胺滴定法测定了Ｂ２Ｏ３／ＺｒＯ２系列催化剂的表面酸性；研究了载体预处理温度对样品表面酸性和结构的影响，以及Ｂ２Ｏ３含量对样品催化性能的影响；比较了Ｂ２Ｏ３负载于ＺｒＯ２，Ａｌ２Ｏ３，ＳｉＯ２，ＴｉＯ２，ＭｇＯ和ＨＺＳＭ－５上催化活性和目的产物选择性的差异，讨论了Ｂ２Ｏ３／ＺｒＯ２催化剂在气固相Ｂｅｃｋｍａｎｎ重排反应中的作用特点     

Zn／HZSM—5分子筛上乙烯,乙烷芳构化的协同作用机理

运用ＮＨ３－ＴＰＤ、ＩＲ－ＯＨ、Ｐｙ－ＩＲ、ＣＯ－ＩＲ及ＸＰＳ等手段对Ｚｎ／ＨＺＳＭ－５及其浸碱催化剂的酸组分和金属组分构成的Ｌ酸性质进行了表征，考察了催化剂对乙烯、乙烷的芳构化作用，发现Ｚｎ／ＨＺＳＭ－５中形成了Ｚｎ＾２＋－Ｌ强酸中心，使分子筛的Ｂ酸中心减少，浸碱也可使分子筛的Ｂ酸减少，芳构化反庆的活性和选择性均与Ｚｎ／ＨＺＳＭ－５的双中心Ｚｎ＾２＋－Ｌ酸的相互匹配密切相关。Ｂ酸和Ｌ酸存在最适合     

高活性沸石酯化催化剂的研究

用硼酸和硫酸对含Ａｌ２Ｏ３的β和ＺＳＭ５沸石进行处理，制备了一系列沸石ＭｘＯｙ和ＳＯ２４／沸石ＭｘＯｙ）催化剂。用ＮＨ３ＴＰＤ和Ｈａｍｍｅｔｔ指示剂法测定了催化剂的表面酸性。对Ｈ２ＳＯ４处理的样品进行了Ｘ射线物相分析。用ＢＥＴ法测定了Ｈβ及ＨＺＳＭ５３８对乙酸的吸附等温线和饱和吸附量。对催化剂的活性，均通过乙酸和乙醇在液相、９０℃和不分水条件下的酯化进行表征。结果表明，ＨβＡｌ２Ｏ３经硼酸和硫酸处理后，乙酸的转化率由３９．５３％提高到５４．９２％。ＨＺＳＭ５３８Ａｌ２Ｏ３经同样处理后，乙酸的转化率由２４．４５％提高到４４．８７％。ＳＯ２４／沸石ＭｘＯｙ的最佳焙烧温度范围是５００～５５０℃。此外，在固定床反应器内于１００～１３０℃和ＬＨＳＶ为６ｈ１的条件下，对ＳＯ２４／ＨβＡｌ２Ｏ３Ｂ２Ｏ３的活性位的稳定性进行了初步实验。反应在１１０℃连续进行１２ｈ后，乙酸的转化率始终稳定在６９％左右。     

化学液相沉积与沸石择形催化性能

在经ＳｉＣｌ４化学液相沉积的ＨＺＳＭ－５沸石催化剂上进行了甲茉歧化、Ｃ６烷烃异构体催化裂解和邻二甲苯异构化反应，随着ＳｉＯ２沉积量增加，沸石内表面性质变化不大，而孔径逐渐缩小，甲苯歧化和邻二甲苯异构化反应的对二甲七选择性提高，Ｃ６烷烃异构体中支链烃３－甲基戊烷和２，２－二甲基丁烷的裂解反应转化率下降，实验结果表明，化学液相沉积是改善沸石催化剂对反应物物产物择形性能的一种有效方法。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.