氧化铈对F-T反应铁锆催化剂的助催化作用

应用ＸＲＤ、ＸＰＳ、Ｍｏｓｓｂａｕｅｒ谱、ＴＰＲ、ＣＯ－ＴＰＤ、ＣＯ＋Ｈ２反应性能测量试等手段研究了ＣｅＯ２对Ｆ－Ｔ合成制低碳烯烃Ｃｅ－Ｆｅ／ＺｒＯ２催化剂催化性能的影响。结果表明，与Ｆｅ／Ｚｒ催化剂相比，加铈助剂后的催化剂Ｆ－Ｔ反应催化活性明显上升。     

Fe_2O_3／ZrO_2催化剂上一氧化碳加氢反应制低碳烯烃 Ⅱ．预处理条件对催化剂结构及性能的影响

用ＴＰＲ，Ｍｏｓｓｂａｕｅｒ谱法，ＸＰＳ，ＸＲＤ及反应评价等手段研究了Ｆｅ２Ｏ３／ＺｒＯ２催化剂的还原行为、铁物种状态和ＣＯ加氢反应性能．结果表明，预处理条件明显影响Ｆｅ２Ｏ３／ＺｒＯ２催化剂表面铁原子的数量、铁锆间的相互作用、催化剂的物相变化以及ＣＯ加氢反应的催化性能．以Ｆｅ２Ｏ３／ＺｒＯ２经氢氟混合气程序升温至７５３Ｋ还原生成的Ｆｅ－Ｚｒ－Ｏ物种为前身，在合成气中进一步还原得到的铁锆催化剂，具有较好的Ｆ－Ｔ反应合成低碳烯烃的选择性．     

镧助剂对Fe/ZrO2催化剂结构及F-T反应性能的影响

用ＸＲＤ，Ｍｏｓｓｂａｕｅｒ谱，ＴＰＲ，ＣＯ－ＴＰＤ和ＣＯ加氢反应性能测试等手段研究了镧助剂对Ｆｅ／ＺｒＯ２催化剂结构及Ｆ－Ｔ合成催化剂性能的影响。结果表明，不同的制备方法明显影响催化剂的结构及反应的性能，镧助剂以Ｌａ２Ｏ３形式存在时，催化剂上甲烷选择降低，烯烃选择性提高；镧助剂以ＬａＦｅＯ３形式存在时，催化剂的催化活性大大提高，但同时甲烷选择性上升，烯烃选择性下降。     

合成气制低碳烯烃K—Fe—MnO／MgO催化剂的研究：Ⅰ.MnO助剂的作用

采用ＣＯ加氢反应、ＣＯ－ＴＰＤ、ＣＯ／Ｈ２－ＴＰＳＲ及Ｃ２Ｈ２／Ｈ２－ＴＰＳＲ等手段，研究合成气制低碳烯烃反应Ｋ－Ｆｅ－ＭｎＯ／ＭｇＯ催化剂中ＭｎＯ的助剂作用。结果表明ＭｎＯ能大幅度提高低碳烯烃的选择性，尤其是乙烯的选择性；ＭｎＯ能抑制催化剂表面的乙烯加氢，因而有利于提高低碳烯烃的选择性及烯／烷的比值。     

合成气制低碳烯烃K－Fe－MnO／MgO催化剂的研究Ⅰ．MnO助剂的作用

采用ＣＯ加氢反应、ＣＯ－ＴＰＤ、ＣＯ／Ｈ＿２－ＴＰＳＲ及Ｃ＿２Ｈ＿４／Ｈ＿２－ＴＰＳＲ等手段，研究合成气制低碳烯烃反应Ｋ－Ｆｅ－ＭｎＯ／ＭｇＯ催化剂中ＭｎＯ的助剂作用。结果表明ＭｎＯ能大幅度提高低碳烯烃的选择性，尤其是乙烯的选择性；ＭｎＯ能抑制催化剂表面的乙烯加氢，因而有利于提高低碳烯烃的选择性及烯／烷的比值。     

Fe_2O_3／ZrO_2催化剂上一氧化碳加氢反应制低碳烯烃──I．催化剂反应性能及反应过程中铁物相的变化

用浸渍法制得一系列不同铁负载量的Ｆｅ２Ｏ３／ＺｒＯ２催化剂，应用催化反应评价结合穆斯堡尔谱对催化剂的ＣＯ加氢反应性能、催化剂活性相结构及催化剂铁物种在合成气反应过程中的物相变化进行了研究．结果表明，铁负载量的大小对于Ｆｅ２Ｏ３／ＺｒＯ２催化剂的Ｆ－Ｔ反应催化性能有很大影响，铁负载量适当时，Ｆｅ２Ｏ３／ＺｒＯ２催化剂铁锆间适当的强相互作用使得催化剂在保持较高催化活性的同时高选择性地生成低碳烯烃，产物分布偏离Ｓｃｈｕｌｚ－Ｆｌｏｒｙ分布规律．     

Fe2O3/ZrO2催化剂上一氧化碳加氢反应制低碳烯烃Ⅱ.预处理条件对催化剂结构及性能的影响

用ＴＰＲ，Ｍｏｓｓｂａｕｅｒ谱法，ＸＰＳ，ＳＲＤ及反应评价等手段了Ｆｅ２Ｏ３／ＺｒＯ２催化剂的还原行为，铁物种状态和ＣＯ加氢反应性能，结果表明，预处理条件明显影响Ｆｅ２Ｏ３／ＺｒＯ２催化剂表面铁原子的数量、铁锆间的相互作用，催化剂的物相变化以及Ｃ氢反应的催经性能，以Ｆｅ２Ｏ２／ＺｒＯ２经氢氩混合氯程序升温至７５３Ｋ还原生成的Ｆｅ－Ｚｒ－Ｏ物种为前身，在合成气中进一步还原得到的铁锆催化剂，具有较好的     

Fe—Silicalite—2催化剂表面CO2加氢反应性能的研究

研究了Ｆｅ／Ｓｉｌｉｃａｌｉｔｅ－２催化剂ＣＯ２加氢低碳烯烃反应性能，利用ＣＯ２－ＴＰＤ，ＣＯ２／Ｈ２－ＴＰＳＲ和ＣＯ／Ｈ２－ＴＰＳＲ表征手段，考察了铁含量及ＭｎＯ助剂对Ｆｅ／Ｓｉｌｉｃａｌｉｔｅ－２催化剂ＣＯ２吸附脱附及加氢反应性能的影响，表明随铁含量增加可提高催化剂对ＣＯ２的吸附能力，有利于提高ＣＯ２加氢反应的转化率。     

助剂钾对二氧化碳加氢反应活性及产物分布的影响

报导助剂Ｋ对Ａｌ２Ｏ３，ＴｉＯ２，ＺｒＯ２担载Ｆｅ催化剂，用于ＣＯ２加氢合成Ｃ２＋烃的催化活性及产物分布的影响。与不含Ｋ的催化剂相比，Ｋ的存在导致Ｆｅ／Ｋ－Ａｌ２Ｏ３的催化活性及Ｃ＾２＋烃选择性明显提高，但使Ｆｅ／Ｋ－ＴｉＯ２的催化活性及Ｃ２＋烃选择性显著下降，而对Ｆｅ／Ｋ－ＺｒＯ２，这种影响并不显著。Ｋ的明显有利于低碳烯烃的生存。     

氧化锆负载氧化铁催化剂上CO加氢反应的研究钾,锰,镧,铈的助剂作用

应用Ｘ－射线衍射，程序升温还遥，穆斯堡尔谱以及ＣＯ＋Ｈ２催化反应性能测试等手术研究了Ｋ，Ｍｎ，Ｌａ，Ｃｅ四种助剂对Ｆｅ２Ｏ３／ＺｒＯ２催化剂结构，还原行为以及ＣＬ＋Ｈ２反应催化性能的影响。     

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.     

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.     

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.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

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.