铁助剂对Rh-Mn-Li/SiO2催化剂CO加氢制二碳含氧化物性能的影响

 采用CO加氢反应、程序升温还原（TPR）、CO吸附和CO脱附等技术，研究了Fe助剂对Rh－Mn－Li／SiO2催化剂上CO加氢合成二碳含氧化物反应的影响．结果表明，Mn，Li和Fe的加入明显提高了Rh催化剂的活性及选择性，特别是在1％Rh－1％Mn－0．075％Li／SiO2催化剂中加入0．05％Fe后，C2＋含氧化物的时空收率由331．6g／（kg·h）提高到457．5g／（kg·h）．但当Fe的加入量继续增加时，催化剂的活性及选择性下降，甲醇的选择性上升．TPR实验表明，当加入少量Fe（0．05％～0．5％）时，TPR的峰面积随Fe加入量的增大而增大，Fe的加入使Rh的还原温度向高温移动，Mn的还原温度向低温移动，Fe的还原峰与Rh和Mn的还原峰相重叠，由此推断这些Fe与Rh是处于紧密接触状态的．当Fe含量增加到1％时，样品在522K出现一个新的谱峰，该峰可归属为与Rh非紧密接触的Fe的还原峰．CO的吸附实验表明，当Fe的加入量超过一定值后，CO吸附量下降．CO的脱附实验表明，在Rh基催化剂中加入少量Fe后，强吸附的CO增多，但当Fe的加入量超过一定值时，强吸附的CO量下降．     

溶剂和酰基受体对α-氰基-3-苯氧基苄醇乙醇的酶促对映体选择性转酯化反应的影响

研究了在有机溶剂中固定化Alcaligenes sp.脂肪酶催化α-氰基-3-苯氧基苄醇乙酯的对映体选择性转酯化反应，考察了不同性质的溶剂和酰基受体对酶的催化活性和选择性以及对产物稳定性的影响．结果发现在弱极性溶剂如正己烷中酶具有较高的催化活性但产物e．e．％值低，而且容易分解；在四氢呋喃等溶剂中酶催化活性相对低，但产物e．e．％值高，也较为稳定；但反应时间太长，会导致产物分解及纯度下降；不同酰基受体对酶反应无显著影响，甲醇为最佳酰基受体，太多醇会导致反应速率下降；溶剂水含量大于2．0％时对酶活性和产物稳定性产生明显不利影响．在优化条件下，酶反应可得到（S）-α-氰基-3-苯氧基苄醇产率＞48％，纯度＞99％e．e．     

反应条件对Zr—Mn—K催化剂合成甲醇,异丁醇的影响

用共沉淀法和超临界干燥法分别制备沉淀型Ｚｒ－Ｍｎ－Ｋ催化剂和超细Ｚｒ－Ｍｎ－Ｋ经剂，由合成气合成甲醇、异丁醇。考察了反应条件对两类催化剂合成甲醇、异丁醇的影响。超细催化剂生成异丁醇活性明显高于沉淀催化剂。在４００℃、５０００ｈ＾－１、１０．０ＭＰａ的反应条件下，超细催化剂异丁醇的含量可达１７．３１％，时空产率为１８．２ｍｌ／ｈ．Ｌｃａｔ．，１６ＭＰａ时异丁醇时空产率达３３．９２ｍｌ／ｈ．Ｌｃａｔ。     

分光光度法同时测定铝质耐火材料中的铁和钛

建立了同时测定铝质耐火材料中铁和钛的方法。以二安替比林甲烷(DAM)为显色剂，在盐酸介质中，显色剂分别与Ti(IV)、Fe(Ⅲ)生成有色络合物，采用双波长法同时测定该两种元素。铁含量的线性范围为0-0．01mg／mL，相关系数r=0．9998；钛含量的线性范围为0—0．002mg／mL，相关系数为r=0．9999。该方法可用于Fe2O3含量大于或等于0．005％、TiO2含量大于或等于0．001％的铝质耐火材料中铁和钛的同时测定。     

生物质气催化合成甲醇的研究

在高压微型反应装置上进行了生物质气合成甲醇的研究。利用组成为H2/CO/CO2 /N2(体积比)=52.5/21.5/22.8/3.2 的富CO2原料气考察了不同温度、压力和空速条件时甲醇的时空产率和质量分数。结果表明,在所考察的范围内,甲醇的产率和质量分数在260 ℃达到最大。产率和质量分数随反应压力升高而增大,空速增加使产率增大,甲醇的质量分数降低。当p=4 MPa,t=260 ℃,WHSV=5 280 h-1时, 甲醇的时空产率为0.79 g·（mL·h）－１,质量分数为96.2%,与工业合成气相比,分别下降25.8％和1.64％。     

微波辅助合成芳基硫醚类衍生物的研究

开展了硫脲与碘代芳烃反应生成芳基硫醚衍生物的微波辅助合成研究。结果表明:在微波辅助条件下,生成的芳基硫醚衍生物的速率均较常规加热条件下增大,并且碘代芳烃对位取代基吸电子能力越强,产率越高。高效地合成了一系列芳基硫醚衍生物,最高产率达到93%。     

杂环基缩胺硫脲的合成及其抗癌活性的研究Ⅳ 含氟哌酸基的缩胺硫脲

研究了结构为I含氟派酸基的缩胺硫脲的合成及其抗癌活性,采用硫酸二甲酯代替昂贵的碘甲烷与肼,二硫化碳反应生成Ⅱ,产率60．0％,Ⅱ与羰基化合物在异丙醇溶剂中缩合反应生成Ⅲ,产率76．2％－86．0％。Ⅲ与氟派酸在正戊醇中回流反应生成Ⅰ,产率46．0－68．0％,经体外筛选表明Ia有一定的抗癌活性。     

Na-W-Mn/SiO_2催化剂中Na对甲烷氧化偶联制乙烯的作用(英文)

采用常规浸渍法制备了一系列Na（wt％）含量不同的Na－W－Mn／SiO_2催化剂,在流动态微型固定床常压反应装置上评价了这些催化剂的甲烷氧化偶联（OCM）制乙烯催化反应性能,并进行了XPS、XRD表征。实验结果表明,Na含量为0．39wt％－2．34Wt％的Na－W－Mn／SiO_2催化剂具有好的甲烷氧化偶联制乙烯性能,此时Mn以对反应有利的晶相存在,同时由于Na的表面富集,引起W、Mn向催化剂表面发生迁移。由此可见,在Na－W－Mn／SiO_2催化剂中,Na是甲烷转化和乙烯生成不可缺少的活性组分之一。     

CeO2和La2O3改性Pd/γ-Al2O3甲醇低温分解催化剂的研究 Ⅱ. La2O3对Pd/CeO2/γ-Al2O3催化剂的结构和性能的影响

 在Pd／CeO2／γ－Al2O3中进一步添加La2O3,并考察了其催化甲醇分解性能．结果表明：La2O3的加入抑制了副产物二甲醚的生成;随着La2O3含量的增加,催化剂活性先降低后升高,w（La2O3）＝10％时甲醇转化率达到极大值（约91．4％）．XRD,BET,NH3－TPD,XPS,H2－TPR和FT－IR等表征结果表明：La2O3自身在γ－Al2O3载体上的分散性很好,并且促进了CeO2在γ－Al2O3载体上的分散及其体相氧的还原,使Pd的分散度进一步提高,并使Pd和CeO2之间的相互作用进一步增强,从而提高了催化剂催化甲醇分解的活性．     

拟薄水铝石的快速分析

建立了一次溶样分别测定拟薄水铝石样品中A12O3、SiO2、Fe2O3、Na2O含量的快速测定方法。采用高压密封消化罐对拟薄水铝石样品进行溶解处理，分取适量样品溶液，测定A12O3、SiO2、Fe2O3、Na2O的相对标准偏差分别为0．20％、2．13％、0.31％、2．62％。     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

关于"对‘燃料电池物理及化学性能的有限时间热力学分析方法'的讨论”答复

把有限时间热力学理论用于化学过程的研究,将会得到一系列新的结论,开展这方面的研究是很有意义的.文献[1]以燃料电池为例,在同时考虑化学反应及传热不可逆性的情况下,研究了燃料电池的性能界限,文献[2]指出了文献[1]计算化学反应及传热不可逆性而引起系统与有关环境的总熵产生率的错误以及由此而导致的结论所存在的问题,并进行了富有启发性的分析与讨论.但文献[2]对于系统与有关环境的总熵产生率的计算也是不正确的,由此得到的其它结论自然不能成立.本文将就此情况下系统与有关环境的总熵产生率的计算再次进行讨论,并给出电池功率和效率的有限时间热力学性能界限.