铁基超细粒子催化剂的F—T反应性能研究：Ⅱ制备参数的影响

详细考察了制备参数对Ｆ－Ｔ反应性能的影响。适量的Ｍｎ可以显著提高Ｆｅ基超细粒子催化剂的低碳烯烃选择性和抑制ＣＨ４的生成，同时活性没有明显降低，但Ｍｎ含量太反而会起到不良影响。与谱能分解法相比，控制降解法制得的Ｆｅ－Ｍｎ超细粒子催化剂具有更高的Ｆ－Ｔ反应活性和低碳烯烃选择性。由不同前驱体制得的Ｆｅ－Ｍｎ催化剂中，以草酸复合物制得的催化剂反应性能最佳。第二金属组分的影响是显著的Ｍｇ导致产物移向轻质组分     

铁基超细粒子催化剂的F－T反应性能研究Ⅲ．反应条件的影响、稳定性及硫中毒

详细考察了反应条件，包括温度、压力、空速、原料气组成对Ｆｅ－Ｍｎ超细粒子催化剂Ｆ－Ｔ反应性能的影响。结果表明，反应条件对催化剂活性，低碳烯烃、ＣＯ＿２以及ＣＨ＿４选择性等都有一定的影响。在所考察的时间范围（８４０ｈ）内，即使在很宽的操作范围内操作，催化剂的稳定性仍能保持良好。硫中毒使催化剂的Ｆ－Ｔ反应活性逐渐下降，产物向轻质组分偏移，Ｃ＿２～Ｃ＿４组分中烯／烷比值下降，但Ｃ＿２～Ｃ＿４烯占总烃的质量百分比略有升高，ＣＯ＿２选择性急剧下降。     

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／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。     

铁基超细粒子催化剂的F—T反应性能研究：Ⅲ.反应条件的影响,稳定性…

详细考察了反应条件，包括温度、压力、空速、原料气组成对Ｆｅ－Ｍｎ超细粒子催化剂Ｆ－Ｔ反应性能的影响。结果表明，反应条件对催化剂活性，低碳烯烃、ＣＯ２以及ＣＨ４选择性等都有一定的影响。在所考察的时间范围（８４０ｈ）内，即使在很宽的作用范围操作，催化剂的稳定性仍能保持良好。硫中毒使催剂的Ｆ－Ｔ反应活性逐渐下降，产物向轻质组分偏移，Ｃ２～Ｃ４组分中烯／烷比值下降，但Ｃ２～Ｃ４烯占总烃的质量百分比略有升高     

锰助剂对Fe／ZrO2催化剂F—T反应催化性能的影响

应用ＸＲＤ，ＸＰＳ，Ｍｏｓｓｂａｕｅｒ谱，ＴＰＲ，ＣＯ化学吸附ＣＯ－ＴＰＤ，ＣＯ＋Ｈ２反应性能测试等手段研究了锰助剂对Ｆ－Ｔ合成制低碳烯烃Ｍｎ－Ｆｅ／ＺｒＯ２催化剂结构及催化性能的影响。结果表明，与Ｆｅ／Ｚｒ催化相比，加锰助剂后的催化剂Ｆ－Ｔ反应催化活性上升，甲烷选择性降低，低碳烯烃选择性增加。     

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。     

改性Fe／MnO催化剂在费—托合成中的反应活性变化

铁催化剂是传统的费托合成催化剂。众多研究表明，Ｆｅ／ＭｎＯ相结合可以打破产物的ＳＦ碳数分布规律，在合成气转化中显示出较高活性并提高产物中低碳烯烃选择性。Ｃｕ在该反应中可增加产物中的含氧化合物成分。我们在过去的工作中［１，２］曾将Ｃｕ担载在Ｆｅ／ＭｎＯ...     

Fe-Mn超细粒子催化剂对FT合成反应的研究Ⅰ.反应条件的影响

在内循环无梯度反应器（Ｂｅｒｔｙ反应器）中研究了Ｆｅ－Ｍｎ超细粒子催化剂费托合成反应的规律。详细考察了温度、压力、空速对ＦＴ反应性能的影响。结果表明,反应条件对催化剂低碳烃及ＣＯ２的选择性等都有一定的影响,在考察的时间范围（１２００ｈ）内,即使在较宽的操作条件下,催化剂仍具有良好的活性和稳定性。还发现随着低碳烯烃选择性的提高,低碳烃的烯烷比下降不明显。     

担体对Fe-MnO催化剂CO加氢合成烯烃性能影响的TPSR表征

考察了不同担体担载的Ｆｅ－ＭｎＯ催化剂上ＣＯ加氢合成烯烃的反应。结果表明担体直接影响低碳烯烃选择性。通过对催化剂的ＣＯ，ＣＯ／Ｈ２，Ｃ２Ｈ４等吸附的ＴＰＳＲ表征及催化剂表面ＣＯ加氢微观反应的研究，证明以碱性担体为基质的ＰＢＣ催化剂具有强吸附ＣＯ能力，且生成的烯烃不易发生二次反应，因而ＰＢＣ催化剂具有较高的烯烃选择性；以酸性担体为基质的ＰＡＣ催化剂对ＣＯ为弱吸附，对Ｈ２为较强吸附，且烯烃会发生强烈的     

纳米尖晶石型Co2MnO4的形成过程及其F-T反应性能

用溶胶凝胶法制备了尖晶石型Ｃｏ２ＭｎＯ４超细粒子，用ＤＴＡＴＧ，ＸＲＤ，ＴＥＭ，ＦＴＩＲ等手段研究了Ｃｏ２ＭｎＯ４超细粒子的形成过程，进而用反应评价结合ＸＲＤ，ＸＰＳ，ＢＥＴ比表面积测试研究了Ｃｏ２ＭｎＯ４催化剂的比表面积和表面结构与其ＦＴ反应性能间的关系．结果表明，Ｃｏ２ＭｎＯ４超细粒子可以在较低温度（２５０～３５０℃）下形成，并具有粒度小，分布均匀等特点．用该法制备的超细粒子Ｃｏ２ＭｎＯ４，其催化活性明显优于相同组成的大颗粒催化剂．     

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.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.