同位素方法在催化反应机理研究中的应用

汪海有　男, 博士, 副教授。从事催化研究。介绍了同位素方法在催化反应机理研究中的几种典型应用

甲烷部分氧化制合成气反应中的氘同位素效应

近几年来,甲烷部分氧化制合成气过程重新引起了人们的极大兴趣。该过程是温和的放热反应,生成的合成气中H_2/CO比约为2,非常适合作甲醇、f-T合成的原料气。该过程使用的催化剂主要是负载型第Ⅷ族过渡金属,如nI,ru,rH,Pd,PT等。关于该过程的催化反应机理,文献中还存在诸多的争论。许多研究者认为反应中部分甲烷首先发生完全氧化反应生成CO_2和H_2O,而后剩余甲烷由生成的CO_2和/或H_2O重整为合成气。与上述观点不香港研究基金委员会资助项

合成气制乙醇催化反应机理述评

合成气制乙醇催化反应机理述评汪海有，刘金波，蔡启瑞（厦门大学固体表面物理化学国家重点实验室，化学系，厦门361005）C1化学是国际上有重大应用背景的化学前沿领域。所谓C1化学是指从一个碳原子的化合物（如CO、CH4、CH3OH）出发合成各种化学品和..

STUDY ON THE MECHANISM OF ETHANOL SYNTHESIS FROM SYNGAS BY INSITU CHEMICAL TRAPPING AND ISOTOPIC EXCHANGE-REACTIONS

5TH TRILATERAL UNITED-STATES / JAPAN / CHINA SYMP ON CATALYSIS 会议地点: NORTHWESTERN UNIV, CTR CATALYSIS & SURFACE SCI, EVANSTON, IL 会议日期: JUN 27-29, 1991The mechanism of ethanol synthesis from syngas over promoted rhodium catalysts has been studied by chemical trapping and isotopic exchange experiments. Mono-deuterated acetaldehyde (CH3CDO) was formed in chemical trapping reaction with CO + D2 as the syngas source and CH3I as the trapping agent, indicating that formyl adspecies was a C1-intermediate in the ethanol synthesis. In the experiment of in-situ chemical trapping and isotopic exchange reactions with (D2O)-O-18 followed by purging with methanol in N2 stream, (CH2DCOOCH3)-O-18(16), (CH3COOCH3)-O-18(16) and (CH3CH2OH)-O-18, (CH3CHO)-O-18 were formed, showing the existence of ketene and acetyl intermediate adspecies and the occurrence of oxygen-isotope exchange between these intermediates and (D2O)-O-18, respectively. Based on the mode of oxygen-isotope exchange between ketene (as well as acetyl) intermediate adspecies and the water formed in reaction, the isotopic repartitioning previously observed by Takeuchi and Katzer [1] can be explained without recourse to the hypothesis of the existence of highly strained oxirene intermediate. These results give further support to the ethanol-formation mechanism proposed by us [2]. Besides these, with substitution of D2 for H-2 in the syngas conversion reaction, noticeable deuterium inverse isotope effects both on methanol and on ethanol formation were observed

无

本文采用现场化截取法研究了Rh系催化剂上合成气转化制乙醉的反应途径．考察了某些助催剂对合成气转化反应的影响，探讨了助催剂的作用本质．我们进行了以下工作：   1．在一系列Rh系催化剂上进行的合成气反应中，以PrOH.H20.CH.OH为截取荆捕获到反应中间体乙烯酮和（或）乙酰基·固定截取剂(CH3.OH.H2O）在物料中的卿，合成气组成比CO/HZ从小到大变化时，截取反应产物（AcOMe、AcOH）的生成百分比相应地从小到大变化，固定合成气组成比，提高物料中CH3OH的含量时，AcOME的时空得率随之提高·以上结系表明中间体乙烯酮和（或）乙酰基和截取剂的反应与它（...学位：理学硕士院系专业：化学化工学院化学系_马克思主义哲学学号：SHAO00003

Study on the mechanism of ethanol synthesis from syngas over rhodium-based catalysts

学位：理学博士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：MJ00003

A Study on the Bond-Order-Conservation Model of the Mechanism of Methane Partial Oxidation to Syngas on Ni(111)

用键级守恒-MOrSE势方法（bOC-MP）研究了甲烷部分氧化制合成气的反应机理.以nI（111）晶面为模型催化剂，应用bOC-MP方法计算了甲烷在有氧与无氧参与下的解离反应及CO和CO2生成反应中各基无反应的活化能垒和反应热焓.计算结果表明：无表面氧参与下的CH4直接解离途径更可能发生；由CH（S）生成CO比由C（S）更易进行.The approach of the bond-order-conservation Morse-potential is introduced to study themechanism of methane partial oxidation to syngas on Ni (111).Calculation results indicate: (1)thedirect eissociation of CH4 without the involvement of sruFace oxygen is more likely to occur; (2)the Formation of CO From CH(s) occurs more readily than From C(s)

Study on effect of using different water absorbents on jujube in slope land under the condition of drip irrigation

利用野外试验方法,在滴灌条件下研究了保水剂在坡地枣林中的使用效果。试验结果证明:施用保水剂的土壤含水量较对照提高了15.3%~39.2%,使10~70 cm土层有较高贮存水量,在年生育期平均降雨量为395 mm情况下,确定红枣整个生育期(为210 d)共灌水4次,按大约每55 d灌溉一次计算,可减少灌溉2次,节约用水264 m3/hm2;0~60 cm土壤平均容重降低0.05~0.16 g/cm3,改善了土壤的通气透水的土壤物理性质,促进了枣树的生长发育,与对照株产5.6 kg相比,四年生红枣单株最高可增产2.85 kg/株;就不同保水剂综合来说,Hs和Hm表现出良好的适宜性

Studies on preparation of catalyst For light oleFin synthesis via carbon monoxide hydrogenation

采用脉冲反应技术，研究了CH4、CH4/O2（2/1）在还原态和氧化态铑基催化剂上的反应情况。观察到，在第一个CH4/O2（2/1）脉冲反应点中，氧化态催化剂上的甲烷转化率、CO2选择性显著高于还原态催化剂；从第二个脉冲反应点开始，氧化态催化剂上的甲烷转化率、产物选择性均与还原态催化剂上的基本接近，表明在第一个CH4/O2（2/1）脉冲反应点中，氧化态催化剂中的铑氧化物已被甲烷还原至金属态铑；从第二个脉冲反应点开始，CH4＋O2反应实际上在还原态的铑位上进行。由此推断，金属态铑是甲烷部分氧化制合成气的活性位The method of "multiple step reFlux impregnation" is put Forward in this article For preparing high dispersion and high iron content supported catalyst For light oleFin synthesis via carbon monoxide hydrogenation, with Fe 3(CO) 12 being the precursor.Characterization by XRD and other techniques shows that,although the iron content is high at 11%(mass), the state of iron on the surFace of the catalyst support is in high dispersion.EFFects of diFFerent temperatures of decarbonylation, iron contents and supports on catalyst preparing chemistry are also investigated.It is Found that an iron content of 5.4 %(mass),using Y zeolite as a support and decarbonylating at 300℃ are more Favourable and ZSM 5 is a best support.The catalyst using ZSM 5 as support exhibits an excellent selectivity of 99.8% to light oleFin.香港研究基金委员会资