High temperature catalytic synthesis of higher hydrocarbons from methane

It has been revealed that methane conversion to higher hydrocarbons over MgO catalyst involves the direct participation of heterogeneous catalyst at contact times of up to 3s and is a homogeneous reaction at 10s.

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MgO. , 3 . , 10 . .

     

Influence of preadsorption of propylene and carbon monoxide on the formation of O2? ion-radicals on ceric oxide

The formation of O ₂ ^– ion-radicals is stimulated by the preadsorption of carbon monoxide and propylene on oxidized ceric oxide. These ion-radicals are shown to possess a much lower thermal stability as compared with O ₂ ^– formed during oxygen adsorption over species reduced by high-temperature heating in vacuum. This is believed to be connected with the interaction of O ₂ ^– ion-radicals with carbonate-carboxylate structures.

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O ₂ ^– . , - O ₂ ^– , . , - O ₂ ^– - .

     

Character of hydrocarbon activation and catalytic activity of solid catalysts in deep oxidation reactions

In terms of a single conception, the relative reactivity of hydrocarbons and the activity of solid catalysts in reactions of deep oxidation are interpreted for the IT_i type mechanism. It is shown that for the oxidation of saturated hydrocarbons the most important is the acceptor interaction of hydrocarbons with catalysts, whereas for the oxidation of unsaturated compounds, of significance are both the donor and acceptor interactions.

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. , , , .

     

A novel approach to selective oxidation of gaseous hydrocarbons

Selective oxidation of hydrocarbons can be performed by some microorganisms possessing monooxygenase activity. Biocatalytic activities of some strains of methanotrophic bacteria (which utilize methane as a sole source of carbon and energy for growth) were investigated in the reactions of partial oxidation of methane and propylene. Formation of commercially valuable oxy-products (methanol, epoxide) occurred with 100% selectivity under the mild reaction conditions studied.

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, . (, ) . , , , 100%- .

     

Kinetic regularities for the interaction of anion-radicals O2? with benzene and toluene on Mo?Mg oxide systems

Interaction of anion-radicals O ₂ ^– with adsorbed forms of benzene and toluene at 293–473 K is shown to be described by an equation corresponding to exponential activation energy distribution of O ₂ ^– . It has been established that under the same conditions the decay rate of O ₂ ^– is higher in the presence of toluene than with benzene.

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, - O ₂ ^– 293–473 , O ₂ ^– . , O ₂ ^– , .

     

Reactivity of oxidized substances and its correlation with catalyst properties in deep oxidation reactions

In terms of the donor-acceptor interaction concept /1/ the relative reactivity (RR) of organic and inorganic compounds and its correlation with catalyst properties in deep oxidation reactions are treated. RR and relative activity of the catalysts are shown to change depending on the predominant character (acceptor or donor) of reactant-catalyst interaction.

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- /1/ (OPC) . , OPC .

     

Electrocatalytic hydroxylation of aniline on metal oxides

Studies of Mn, Cr, Cu, La, Sb, V, Co and W oxides as catalysts for the electrocatalytic oxidation of aniline to p-aminophenol have revealed the electrocatalytic activity of WO₃. A mathematical model for the kinetics of analine oxidation on WO₃ is suggested that agrees fairly well with the experimental data.

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Mn, Cr, Cu, La, Sb, V, Co, W -. , . , , .

     

Activation of hydrocarbons in the oxidative dimerization of methane over alkaline earth metals

Oxidative dimerization of methane over alkaline earth metal oxides and phosphates has been studied. The ratedetermining step is heterolytic C–H bond dissociation of methane on surface basic sites of the catalysts.

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- . , C–H .

     

Catalytic ammoxidation of coal

Ammoxidation of coal on oxide catalyts has shown the possibility of hydrocyanic acid formation at sufficiently low temperatures.

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. .

     

基于粗糙近似的Web事务聚类改进算法

针对现有Web使用记录挖掘方法发现的知识和规则存在不精确或不完全的问题,提出了一种改进的基于粗糙近似的Web事务聚类算法.该算法首先对原有算法得到的每个类,用关系矩阵找出在这个类中不满足传递性的对象,然后在该对象的集合(类)上用关系矩阵找出在这个类中不满足传递性的对象,再对每个类进行分割,使其满足关系R的传递性,克服了现有算法不满足关系的传递性和在某些情况下得到的结果不准确的缺点.