改进型铜基甲醇合成催化剂NC208的活性相谱学表征

利用ＸＲＤ和ＦＴＩＲ等谱学方法，对改进型铜基联醇催化剂ＮＣ２０８和工业催化剂Ｃ２０７的活性相进行了谱学表征。实验结果表明，联醇铜基甲醇合成催化剂的活性中心可能是“Ｃｕｘ＾０－Ｃｕ＾＋－Ｏ－Ｚｎ＾２＋／Ａｌ２Ｏ３－ＭＯｘ”；添加少量金属氧化物助剂的改进型ＮＣ２０８催化剂工作表面Ｃｕ＾＋活性位的浓度比Ｃｕ－Ｚｎ－Ａｌ三组份工业催化剂Ｃ２０７高；ＮＣ２０８催化剂能维持工作表面具有较大的Ｃｕ＾＋／Ｃｕ＾０     

CuO／γ－Al_2O_3催化剂铜物种的分散状态研究

本文用ＸＲＤ，ＸＰＳ，ＴＰＲ和ＥＳＲ研究焙烧温度对ＣｕＯ／γ－Ａｌ２Ｏ３催化剂中铜物种分散状态的影响。在低负载量（５％Ｃｕ）不高于７００℃焙烧时，以“表面尖晶石”形式存在的铜物种，包括两种分散状态：分散的和高度分散的，后者与载体有较强的相互作用，焙烧温度升高，使铜物种分散状态变化，高度分散的铜物种量增加．当焙烧温度为９００℃或更高时，生成ＣｕＡｌ２Ｏ４以及载体的相变使高度分散的铜物种减少，从３５０～１０００℃，存在一个使铜物种达到最佳分散态的温度，约为７００℃。在９００℃焙烧时，增加铜的负载量使ＣｕＡｌ２Ｏ４的生成量增加。     

活性碳纤维ZnO—SACF氧化还原机理的研究

本文借助于ＩＲ，ＴＧ和ＸＰＳ，研究了ＺｎＯ－ＳＡＣＦ制备过程中及其吸附Ａｇ＾＋和Ａｕ＾３＋前后的化学结构变化。实验结果表明：从ＳＡＣＦ到ＺｎＯ－ＳＡＣＦ，纤维表面上的Ｏ／Ｃ原子比和含氧基团如Ｃ＝Ｏ和ＣＯＯ都有所减少；ＺｎＯ－ＳＡＣＦ上还原性功能基团主要是－Ｃ－ＯＨ，当ＺｎＯ－ＳＡＣＦ吸附Ａｇ＾＋后，－Ｃ－ＯＨ被氧化为－Ｃ＝Ｏ，而当其吸附Ａｕ＾３＋后，－Ｃ－ＰＨ被氧化为－Ｃ＝Ｏ和－（Ｏ＝Ｃ）－ＯＨ，     

二氧化碳加氢合成甲醇铜基催化剂表面组成的研究

本文分别采用ＸＲＤ、ＥＳＲ、ＸＰＳ和ＸＡＥＳ等技术对于二氧化碳加氢低压合成甲醇用ＣｕＯ，ＣｕＯ－ＺｎＯ，ＣｕＯ－ＺｎＯ－Ａｌ＿２Ｏ＿３，ＣｕＯ－ＺｎＯ－ＺｒＯ＿２催化剂在不同条件下表面Ｃｕ、Ｚｎ、Ａｌ、Ｚｒ的存在价态进行了深入分析。实验发现催化剂在还原前Ｃｕ以Ｃｕ￣２＋存在，在还原后和反应状态下以Ｃｕ￣０存在；Ｚｎ在还原后和反应状态下有部分被还原为Ｚｎ￣（２－δ）（０＜δ＜２），Ｚｒ和Ａｌ仍保持其还原前价态。催化剂的表面化学组成为：Ｃｕ￣０／Ｚｎ（２－δ）￣＋／Ｚｒ￣４＋／Ａｌ￣３＋／Ｏ￣２－。     

雾化高温分解法铜基甲醇合成催化剂的活性位

本文测定了雾化高温分解（ＡＨＴＤ）法制备的一系列Ｃｕ／ＺｎＯ催化剂的铜表面积，并将其与催化活性进行了关联。结果表明在含有ＣＯ２的原料气中，催化剂活性位可能是由Ｃｕ＾０组成。ＡＨＴＤ法Ｃｕ／ＺｎＯ催化剂的ＣＯ－ＴＰＤ显示出两个明显的脱附峰，低温脱附的ＣＯ可能是吸附在Ｃｕ＾＋上的。Ｃｕ＾＋在无ＣＯ２的原料气中起了催化作用。Ｘ射线诱导Ａｕｇｅｒ谱测定结果表明，还原活化后和反应２小时后催化剂表面除大量的Ｃ     

氧化锆对铜基甲醇合成催化剂的促进作用(英文)

采用离子掺杂价态补偿原理,在Ｃｕ－Ｚｎ－Ａｌ甲醇合成催化剂中添加适量氧化锆助剂研制Ｃｕ－Ｚｎ－Ａｌ－Ｚｒ催化剂的特性。实验结果表明,最佳反应温度为２３０℃,比Ｃｕ－Ｚｎ－Ａｌ约低１０℃。采用ＸＲＤ、ＵＶＤＲ、ＦＴＩＲ、ＴＰＤ和ＴＰＲ等谱学方法对２种催化剂进行表征显示,铜基催化剂的活性位可能是“Ｃｕ０－Ｃｕ＋－Ｏ－Ｚｎ２／Ａ２Ｏ３－ＺｒＯ２”,工作态Ｃｕ－Ｚｎ－Ａｌ－Ｚｒ催化剂表面上Ｃｕ／Ｃｕ０的比值、价态稳定性和对ＣＯ的吸附量均大于Ｃｕ－Ｚｎ－Ａｌ,这与该催化剂具有较好的低温活性和较高的热稳定性密切相关。     

Cu/ZrO2-Al2O3上表面氧物种脱附及其对催化性能的影响

采用ＸＲＤ,ＴＰＤ－ＭＳ和ＴＰＲ方法研究了ＺｒＯ２的改性对ＣｕＯ／γ－Ａｌ２Ｏ３催化剂上铜物种人散状态,表面氧物种的脱附和恢复性能,铜物种还原再氧行为的影响,并ＣＯ氧化反应为探针考察了催化剂的氧化活性,结果表明,ＺｒＯ２的存在的铜物种在γ－Ａｌ２Ｏ３载体上的分散容量降低,促进ＣｕＯ／γ－Ａｌ２Ｏ３催化剂上表面氧物种的脱附,同时有效地促进铜物种的还原,从而增加ＣＯ的氧化活性,实验还发现热处理条件对催     

V2O5在载体表面的分散状态与表面酸性

用ＸＲＤ，ＸＰＳ研究了Ｖ２Ｏ５在γ－Ａｌ２Ｏ３，ＳｉＯ２，ＴｉＯ２等载体上的分散状态，测定了最大分散容量。结果表明，Ｖ２Ｏ５在γ－Ａｌ２Ｏ３和ＳｉＯ２上能形成亚单层分散，分散容量分别为理论单层量的６０％和４５％；Ｖ２Ｏ５在ＴｉＯ２上优先形成单层，然后形成多层结构。Ｖ２Ｏ５在γ－Ａｌ２Ｏ３上分散可使表面酸性有所增加；Ｖ２Ｏ５在ＳｉＯ２上分散使表面酸性剧增，酸位数和表面Ｖ＾５＋的摩尔比高达０．５左右；     

酸性镀铜体系的交流阻抗研究

研究了基础溶液（０．３ｍｏｌ／ＬＣｕＳＯ４＋１．９４ｍｏｌ／ＬＨ２ＳＯ４）以及添加６０ｍｇ／ＬＣｌ＾－，３００ｍｇ／ＬＯＰ－２１，３０ｍｇ／ＬＰＥＧ－６０００，１０ｍｇ／Ｌ２－噻唑啉基－二硫丙烷酸钠（代号ＴＤＹ，自合成添加剂）后体系的阻抗行为，结果表明：１）Ｃｌ＾－在铜沉积中有增大阴极极化的作用；２）铜离子的放电为分步反应；即Ｃｕ＾２＋→Ｃｕ＾＋；Ｃｕ＾＋→Ｃｕ（吸附）→Ｃｕ（晶格），在含有Ｃｌ＾     

CuCl/γ-Al2O3上NO脱除过程研究

设计了一系列的对比实验,利用ＸＲＤ,ＸＰＳ,ＴＰＲ,ＥＸＡＦＳ等技术,系统研究了ＣｕＣｌ／γ－Ａｌ２Ｏ３上的ＮＯ脱除反应过程。结果发现,ＣｕＣｌ／γ－Ａｌ２Ｏ３样品暴露在空气中,表面被部分氧化生成ＣｕＣｌ２及ＣｕＯ等,在高温处理和反应过程中,造成样品表面氯的损失,同时生成更多的ＣｕＯ,因而得新还原处理后测活性时,得到高分散的金属铜,使样品的ＮＯ分解活性提高,但由于ＮＯ对低价铜有很强的氧化作用,ＮＯ     

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.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.