Published in Kinetics and Catalysis
The nonisothermal nature of hydrocarbon pyrolysis explains the differences in the critical temperatures of soot formation in the experimental studies of these processes. When reaction heats are taken into account, the critical temperatures become close to 1600 K for all the systems studied. The estimated standard enthalpy of carbon atom formation i...
Published in Kinetics and Catalysis
The low-temperature periodical activation of the catalysts based on the metal complexes of nitrogen-containing carbon is observed in the course of isopropylbenzene oxidation. The concentration of the surface hydroperoxide groups responsible for the chain process affects both catalyst deactivation and reactivation. Possible reactions responsible for...
Published in Kinetics and Catalysis
Liquid-phase hydrodechlorination of hexachlorobenzene was kinetically studied in the presence of both nickel (Ni/C) and palladium-promoted nickel (2%PdNi/C) catalysts under different reaction conditions. Molecular hydrogen (at 1 and 20 atm) and sodium borohydride (NaBH4) were used as reducing agents. In the presence of the nickel catalyst, the hydr...
Published in Kinetics and Catalysis
A model for isothermal homogeneous nucleation is proposed that improves the classical model. A quasiequilibrium distribution of clusters was calculated on a basis of the Frenkel’-Lothe-Pound theory. The dependence of the free energy of clusters on their size was represented by an interpolation formula relating the free energy of dimers and large cl...
Published in Kinetics and Catalysis
New catalytic systems based on porphyrin complexes of Ni2 cluster and capable of activating C-H and H-H bonds are proposed. DFT calculations showed that a Ni2 cluster can coordinate Ni-porphyrin with a considerable gain in energy. The structures of the products of methane and hydrogen activation were discussed.
Published in Kinetics and Catalysis
The activity and selectivity of the Mo-Ni catalysts prepared by the impregnation of supports (γ-Al2O3, hydrated titanium dioxide (HTD), and palygorskite-montmorrilonite clay (PMC)) are studied in the reactions of black oil hydrotreatment. The alumina support provides a higher catalytic activity in the hydrogenation of aromatics. The highest efficie...
Published in Kinetics and Catalysis
Spatial distributions of the desorption flow (SDDF) of CH4, N2 and azomethane (CH3N=NCH3) on molybdenum, O2 and N2 on indium, and N2 on iron were measured by TPD/TPR with angular resolution and described by the Comsa equation. The activation energy of chemisorption and the effect of the precursor state on the total desorption rate were estimated fr...
Published in Kinetics and Catalysis
The kinetics of dissociative adsorption of oxygen was studied by the Monte Carlo method for a model which supposed that absorption occurs with a high rate only on steps and that Oads may migrate from steps onto terraces and backward. At the relatively low activation energy of diffusion from steps onto terraces Edif∼ 75 kJ/mol (Edif is lower by 4 kJ...
Published in Kinetics and Catalysis
Methane pyrolysis and steam reforming were studied over a series of nickel catalysts (Ni-Al2O3, Ni/MgO, and Ni/LiAlO2) under the same conditions (650-750°C, PCH4 = 0.001-0.03 MPa). Unlike heterogeneous reaction of pyrolysis, some of the steps of steam reforming of methane occur in the gas phase. When gasphase reactions were suppressed, the rate and...
Published in Kinetics and Catalysis
Island structures on the chemically modified surface of silica are synthesized by the method of matrix prints. Dichlorosilicon phthalocyanine and copper naphthalocyanine were used as molecular templates. Two types of heterogeneous surfaces are prepared by this method: the islands of nonmodified silica on the trimethylsilylated silica (the first typ...
