PVP负载Pd—Co催化剂催化六氯苯的加氢脱氯

研究了温和条件下钯催化剂催化六氯苯加氢脱氢反应。结果表明,ＰｄＣｌ２催化活性不高,而ＰＶＰ负载ＰｄＣｌ２活性较高,ＰＶＰ负载Ｐｄ－Ｃｏ催化剂具有双金属协同效应,提高了催化活性。５５℃下,该催化剂在Ｃｏ／Ｐｄ摩尔比为０．５时表现出最高的催化活性。     

苯酚氧化羰化合成碳酸二苯酯的新型PdCl2-Co(Pyca)2催化体系

研究了新型的Ｐｄ－Ｃｏ催化体系催化氧化碳化苯酚合成碳酸二苯酯。当ｎ（ＰｄＣｌ２）：ｎ「Ｃｏ（Ⅱ）」：ｎ（四丁基化铵）：ｎ（苯醌）＝１：１：１０：２５,Ｔ＝１２０,Ｐ＝２．５ＭＰａ（Ｐｃｏ／Ｐｏ２＝４：１）,反应时间８ｈ,ＰｄＣｌ２－Ｃｏ（Ｐｙｃａ）２比ＰｄＣｌ２－Ｃｏ（ＯＡｃ）２的催化活性高。当使用ＰｄＣｌ２－Ｃｏ（Ｐｙｃａ）２催化剂时,ＤＰＣ的产率为６．０３％。最佳的反应温度是１２０℃,ＤＰＣ的产率随着体系的总压增加而增大,当压力升到３．５ＭＰａ时,ＤＰＣ产率为８．５３％。     

硝基芳烃氢化还原反应中高分子负载催化剂的双金属协同效应

制备了聚Ｎ－乙烯基－２－吡咯烷酮ＰＶＰ负载钯催化剂Ｐｄ／ＰＶＰ及各种双金属催化剂（１－ｍ）Ｐｄ－ｍＭ／ＰＶＰ，并用于硝基芳烃的加氢还原中，其中Ｐｄ／ＰＶＰ中加入Ｈ２ＰｔＣｌ６的效果最佳，碱的用量、溶剂和Ｐｄ、Ｐｔ的比例都对催化剂的活性有明显的影响，双金属催化剂０．８０Ｐｄ－０．２０Ｐｔ／ＰＶＰ在温和条件下能高活性，高选择性地催化硝基芳烃还原，得到相应的芳胺。     

双重负载钯催化剂高选择性地催化氯苄羰基化生成苯乙酸甲酯

在ＰＰｈ３存在下,高分子负载的ＰＶＰ－ＰｄＣｌ２及易与产物分离的,双重负载的ＰＶＰ－ＰｄＣｌ２／Ａｌ２Ｏ３催化氯苄与一氧化碳和甲醇羰基化,直接生成苯乙酸甲酸甲酯。实验结果表明,ＰＶＰ－ＰｄＣｌ２／Ａｌ２Ｏ３－４ＰＰｈ３不仅易于分离回收,而且具有高活性和高选择性。     

高分子负载型双金属催化剂催化苯乙烯及其衍生物的氢酯基化反应

首次用高分子负载型双金属催化剂ＰＶＰ－ＰｄＣｌ２－ＣｕＣｌ２／Ｐｈ３体系催化苯乙烯衍生物的氢酯基化反应,在非常温和的条件下,转化率及区域选择性均可接近１００％。ＸＰＳ、ＩＲ和ＴＥＭ分析表明,Ｐｄ（Ⅱ）、Ｃｕ（Ⅱ）与ＰＶＰ中的Ｎ、Ｏ原子配位形成配位键,从而将金属离子锚定在ＰＶＰ上。ＰＶＰ能够阻止钯粒子增长,因而有效地防止了金属聚集成钯黑沉淀导致的催化剂失活。     

微量贵金属对Co／γ-Al_2O_3的作用及其结构表征Ⅰ．Co－M／γ－Al_2O_3催化剂的活性及其XRD和XPS表征

催化剂采用等量浸渍法，先后将Ｃｏ与贵金属组分浸于γ－Ａｌ２Ｏ３上，经５００℃焙烧，４５０℃氢气还原制得（ｍＣｏ３Ｏ４／ｍＡｌ２Ｏ３＝０．０８，ｍ贵金属／ｍ催化剂＝１／１０００）．ＣＯ氧化活性的测定结果表明，贵金属Ｐｔ和Ｐｄ与Ｃｏ之间具有明显的协同催化作用，而Ｒｈ与Ｃｏ的协同作用较差．在Ｃｏ－Ｐｔ／γ－Ａｌ２Ｏ３和Ｃｏ－Ｐｄ／γ－Ａｌ２Ｏ３上，ＣＯ１００％转化的温度较在Ｃｏ／γ－Ａｌ２Ｏ３上下降了约６０℃，而在Ｃｏ－Ｒｈ／γ－Ａｌ２Ｏ３上仅下降了２５℃左右．ＸＲＤ和ＸＰＳ的表征结果表明，Ｃｏ／γ－Ａｌ２Ｏ３中Ｃｏ以高分散的金属Ｃｏ相和类似ＣｏＡｌ２Ｏ４的尖晶石相存在，而Ｃｏ－Ｍ／γ－Ａｌ２Ｏ３（Ｍ＝Ｐｔ，Ｐｄ，Ｒｈ）催化剂中，Ｃｏ相已完全被还原为零价．高分散的金属钴相和贵金属相的协同作用，可能与氧从贵金属至Ｃｏ相上的溢流效应有关．     

双重负载钯催化剂用于硝基化合物的催化加氢

将可溶的聚乙烯吡咯烷酮负载的钯催化剂进一步负载到γ－Ａｌ２Ｏ３上，得到双重负载的钯催化剂。在少量碱的存在下，这种双重负载的钯催化剂在常温常压下对硝基苯的催化加氢表现出非常高的活性。γ－Ａｌ２Ｏ３负载的聚乙烯吡咯烷酮钯催化剂［ＰＶＰ－Ｐｄ／Ａｌ２Ｏ３（ｍｅｔｈｏｄＢ）］对硝基苯和ｐ－甲基硝基苯加氢的ＴＯＦｍａｘ（ｍａｘｉｍｕｍｔｕｒｎｏｖｅｒｆｒｅｑｕｅｎｃｙ，ｎ（Ｈ２）／（ｎ（Ｐｄ）．ｔ）），分别     

水溶性钯配合物催化化柠檬醛的选择加氢研究

研究了以水溶性ＰｄＣｌ２（ＴＰＰＴＳ）２为催化剂，在水／有化机物两相体系中，添加ＴＰＴＳ、ＣＴＡＢ、ＰＶＡ、明胶和碳酸钠和柠檬醛加氢反应及催化剂稳定性的影响，添加配体ＴＰＰＴＳ、明胶或表面活性ＣＴＡＢ有利于减少钯黑的形成，但会引起催化活性降低；而添加ＰＶＡ和Ｎａ２Ｃｏ３，虽然都不能抑制钯黑的形成，但后者的添加会明显提高加氢速度；发现，明胶加碳酸钠的体系不仅可以稳定催化剂的活性物种，避免钯黑的析出，     

双核钯配合物（Ph2P（o—C6H4CO）PDCl）2.2CH2Cl2的合成,结构和…

合成了双氯桥双核钯配合物（Ｐｈ２Ｐ（ｏ－Ｃ６Ｈ４ＣＯ）ＰｄＣｌ）２．２ＣＨ２Ｃｌ２，进行了元素分析，红外光谱表征和晶体结构测定，研究了其催化氢化性能，有３０～８０℃，氢分压１．０～５．０ＭＰａ的范围内，发现该配合物是催化氢化丙烯酸为丙酸的有效催化剂，晶体（Ｐｄ２Ｃｌ２（Ｃ１９Ｈ１４ＯＰ）２．２ＣＨ２Ｃｌ２属Ｐ１空间群，ａ＝０．９３０４（３）ｎｍ，ｂ＝１．０３９２（２）ｎｍ，ｃ＝１．１０６２（３）ｎ     

甲烷与二氧化碳转化制合成气的研究 Ⅰ.负载型钴金属催化剂的催化性能

采用固定床流动反应装置研究了高温焙烧的负载型钴金属催化剂对甲烷与二氧化碳转化制合成气的催化性能，考察了催化剂活性组分、预处理温度及反应条件等对合成气生成量的影响，并用色谱法测定了催化剂上的积炭量．结果表明，钴负载量高于１２％时，在１０７３～１４７３Ｋ焙烧的Ｃｏ／Ａｌ２Ｏ３催化剂不仅具有高的催化活性，而且具有独特的抗积炭性能．ＴＰＲ，ＸＲＤ和催化反应结果表明，来源于ＣｏＡｌ２Ｏ４尖晶石的金属Ｃｏ以及ＣｏＡｌ２Ｏ４尖晶石对催化剂的活性和抗积炭性能起着关键作用，其活性特征在许多方面不同于低温焙烧的Ｃｏ／Ａｌ２Ｏ３或Ｎｉ／Ａｌ２Ｏ３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.     

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.