丙烷直接氨氧化制丙烯腈催化剂的研究进展

丙烷直接氨氧化制丙烯腈是一条潜在的具有巨大经济效益的丙烯腈生产路线。本文概述了丙烷直接氨氧化制丙烯腈的催化反应机理，对丙烷直接氨氧化制丙烯腈的催化反应路径进行了归纳，同时对丙烷直接氨氧化制丙烯腈催化剂设计的思想以及日前所开发的几类丙烷直接氨氧化制丙烯腈催化剂体系加以了总结，重点介绍了锑酸盐和钼酸盐催化剂，对锑酸盐和钼酸盐催化剂活性相的结构、影响活性相形成的因素以及催化剂的结构与催化反应性能的关系等问题作了阐述。     

丙烯氨氧化合成丙烯腈液体产物分析

本文利用１０３型气相层析仪与电子计算机联接，分析了丙烯氨氧化合成丙烯腈的液体产物。研究了分析方法的重复性和准确性，讨论了不同进样量和不同的校正因子对扁平乙腈峰的影响。结果表明，本方法可取代先有的丙烯腈化学分析方法。     

科研成果简介

长春应用化学研究所 500—900℃新型稀土高温热敏电阻元件 半导体透明玻璃管炉 DCG-1型多功能程序给定器 潜油电机电缆插头密封材料 丙烯氨氧化合成丙烯腈催化剂-DB75催化剂     

丙烯氨氧化合成的丙烯腈中微量杂质的气相色谱分析

提出了可以分析丙烯氨氧化合成的丙烯腈中微量杂质的气相色谱法.采用癸二酸二壬酯/6201型担体色谱柱,可以使乙腈在丙烯腈之前流出,提高了分析乙腈的灵敏度.文中列出了各微量杂质的最低鉴定量,测定的标准误差在±10％以内.总分析时间约1小时.     

利用14C标记物研究锑铁催化剂上丙烯氨氧化的反应机理

为研究锑铁催化剂上丙烯氨氧化反应机理,以[1-~(14)C]丙烯进行反应,通过化学降解测定了产物丙烯腈和乙腈分子中的放射性分布。结果表明丙烯腈中C_2H_3和CN基上的放射性之比为55.5∶44.5,证明89％的丙烯腈是按烯丙基机理生成的。另外根据各种副产物的放射性分布推测出:反应过程中丙烯腈可在单键处断裂——乙烯基碳原子氧化成CO和CO_2,而氰基则转化成HCN,还有少量在双键处断裂生成乙腈;而丙烯则可通过烯丙基均匀断裂分别生成CO,CO_2和HCN,还有少量烯丙基在一端断裂生成乙腈。由乙腈的甲基和氰基上有大致相等的放射性这一实验结果推测出,烯丙基转化为乙腈是由含氮基团引向烯丙基的中间碳原子引起的。本文还以[1,3-~(14)C]丙烯腈为示踪物进一步验证了上述结论,并推测出乙腈,HCN,CO和CO_2均是平行生成的,而没有发生相互转化。     

丙烯氨氧化合成丙烯腈过程中的尾气分析

在丙烯氨氧化合成丙烯腈过程中，尾气内含有因反应而生成的ＣＯ２，ＣＯ，Ｃ２Ｈ４，未反应完全的Ｃ３Ｈ６，Ｏ２和不参与反应的Ｎ２以及丙烯原料气中少量的Ｃ３Ｈ８。使用含有双阀、双检测器、双色谱柱的气相色谱系统可使上述所有气体得到分离，而且分离效果好，定量准确，操作简单，实用性强     

丙烯在铁锑氧化物上的吸附和氨氧化

用吸附和程序升温脱附的方法,研究了不同组成铁锑氧化物催化剂上丙烯的吸附和脱附以及催化剂的再氧化。催化剂中Sb原子含量由零增加至90％时,单位表面丙烯的吸附量总的变化趋势是增加的,脱附后催化剂的再氧化吸氧量也呈现同样的规律。不同组成铁锑氧化物上丙烯氨氧化合成丙烯腈的催化活性和选择性与丙烯的吸附量无直接对应关系。丙烯程序升温脱附和对脱附产物的分析表明,不同组成的催化剂的表面氧化能力和脱附性质有明显的区别。由Mossbauer谱的分析结果可以认为锑酸铁是催化剂表面的主要提供者。根据丙烯吸附和催化反应的结果,推测选择性氧化的吸附中心可能与锑离子相关。     

丙烯氨氧化合成丙烯腈过程中的尾气分析

 在丙烯氨氧化合成丙烯腈过程中，尾气内含有因反应而生成的ＣＯ２，ＣＯ，Ｃ２Ｈ４，未反应完全的Ｃ３Ｈ６，Ｏ２和不参与反应的Ｎ２以及丙烯原料气中少量的Ｃ３Ｈ８。使用含有双阀、双检测器、双色谱柱的气相色谱系统可使上述所有气体得到分离，而且分离效果好，定量准确，操作简单，实用性强。     

丙烯腈合成过程中丙烯腈及其杂质的色谱分析

１引言采用丙烯氨氧化法合成丙烯腈，在反应生成丙烯腈的同时，还有一些副产物如乙腈、丙烯醛、丙烯酸、ＣＯ、ＣＯ２等杂质生成。文献报道的丙烯腈及其杂质分析方法主要有极谱法、光谱法和色谱法，其中色谱法最为常用。对于色谱法分析，国标中指定固定相是ＧＤＸ－５０２，于桂霞等使用ＧＤＸ－１０２和上试４０２有机载体混装填充柱。这类固定相的主要缺点是使用一段时间后保留值改变，分离度下降且分析时间较长。近来文献有关丙烯腈色谱分析改进方法大多涉及到毛细管柱的使用。本文采用ＦＦＡＰ毛细管色谱法内标定量、同时测定丙烯腈、乙…     

丙烯腈合成过程腈及其杂质色谱分析

１引言采用丙烯氨氧化法合成丙烯腈，在反应生成丙烯腈的同时，还有一些副产物如乙腈、丙烯醛、丙烯酸、ＣＯ、ＣＯ２等杂质生成。文献中报道的丙烯腈及其杂质分析方法主要有极谱法、光谱法和色谱法，其中色谱法最为常用。对于色谱法分析，国标中指定固定相是ＧＤＸ－５０２，于桂霞等使用ＧＤＸ－１０２和上试４０２有机载体混装填充柱。这类固定相的主要缺点是使用一段时间后保留值改变，分离度下降且分析时间较长。本文采用ＦＦＡＰ毛细管色谱法内标定量，同时测定丙烯腈、乙腈、丙烯醛、丙烯酸等。该方法快速、方便，用于丙烯腈合成过程…     

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.     

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.