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首页> 外文学位 >THE MECHANISM AND KINETICS OF FISCHER-TROPSCH SYNTHESIS OVER SUPPORTED RUTHENIUM CATALYSTS.
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THE MECHANISM AND KINETICS OF FISCHER-TROPSCH SYNTHESIS OVER SUPPORTED RUTHENIUM CATALYSTS.

机译：负载型钌催化剂上费-托合成的机理和动力学

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A detailed study of the kinetics of the Fischer-Tropsch synthesis of hydrocarbons, methanol, and acetaldehyde, over alumina- and silica-supported ruthenium catalysts has been carried out over a broad range of reaction conditions. Based on these results and information taken from the literature, mechanisms for the formation of normal paraffins, (alpha)-olefins, methanol, and acetaldehyde have been proposed.; Rate data were obtained between 448 and 548K, 1 and 10 atm, and H(,2)/CO ratios between 1 and 3, utilizing a micro flow reactor operated at very low conversions. These conditions allowed the intrinsic reaction kinetics to be observed with minimal interference from secondary reactions. In addition to the studies performed with H(,2)/CO mixtures, a series of experiments were carried out utilizing D(,2)/CO mixtures. These studies were used to help identify rate limited steps and steps that were at equilibrium.; A complementary investigation, carried out by in situ infrared spectroscopy, was performed using a Fourier Transform spectrometer. The spectra obtained were used to identify the modes of CO adsorption, the CO coverage, and the relative reactivity of different forms of adsorbed CO. It was established that CO adsorbs on alumina-supported Ru in, at least, two forms: (i) Ru-CO and (ii) OC-Ru-CO. Only the first of these forms participates in CO hydrogenation. The coverage of this species is described by a simple Langmuir isotherm.; The kinetics of hydrocarbon synthesis, the olefin to paraffin ratio for each product, and the probability of chain propagation can all be interpreted on the basis of the reaction mechanism described below. Reaction is initiated by the adsorption of CO and its subsequent dissociation. Atomic oxygen is rejected as H(,2)O and the carbon undergoes stepwise hydrogenation to form CH(,x)(x = 1-3) species. Methane is formed by reductive elimination of methyl groups while the formation of higher molecular weight products is initiated by the addition of a CH(,2) unit to an adsorbed CH(,3) group. Further chain growth then proceeds via a similar process. Olefins are formed by (beta)-elimination of hydrogen from an adsorbed alkyl group and paraffins are formed by reductive elimination of an alkyl group. Rate expressions based on this mechanism are reasonably consistent with the experimental data. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI
机译：在广泛的反应条件下，对氧化铝和二氧化硅负载的钌催化剂进行的费托合成烃，甲醇和乙醛的动力学进行了详细研究。基于这些结果和从文献中获得的信息，已经提出了形成正链烷烃，α-烯烃，甲醇和乙醛的机理。利用以非常低的转化率运行的微流反应器，获得了在448至548K，1至10 atm，H（，2）/ CO比在1至3之间的速率数据。这些条件使得可以观察到固有的反应动力学，而没有受到次要反应的干扰。除了使用H（，2）/ CO混合物进行研究以外，还使用D（，2）/ CO混合物进行了一系列实验。这些研究被用来帮助确定速率受限的步骤和处于平衡状态的步骤。使用傅立叶变换光谱仪进行原位红外光谱法的补充研究。所获得的光谱用于识别CO的吸附方式，CO的覆盖率以及不同形式的CO的相对反应性。确定了CO至少以两种形式吸附在氧化铝负载的Ru上：（i） Ru-CO和（ii）OC-Ru-CO。这些形式中只有第一种参与CO加氢。该物种的覆盖范围由一个简单的Langmuir等温线描述。烃合成的动力学，每种产物的烯烃与石蜡的比率以及链增长的可能性都可以根据下述反应机理来解释。通过吸附CO及其随后的离解来引发反应。原子氧被拒绝为H（，2）O，并且碳经历逐步加氢以形成CH（，x）（x = 1-3）物质。甲烷是通过甲基的还原消除而形成的，而更高分子量产物的形成是通过向吸附的CH（，3）基团中添加CH（，2）单元而引发的。然后，通过类似的过程进一步进行链增长。烯烃通过从吸附的烷基上消除氢的β形成，而链烷烃则通过烷基的还原消除而形成。基于这种机制的速率表达式与实验数据合理地一致。 。 。 。 （作者的摘要超出了规定的最大长度。经作者许可，在此处停产。）UMI

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