Reaction of toluene with ozone in the liquid phase

Reaction of toluene with ozone in acetic anhydride was studied. The dependence of the direction, selectivity, and extent of oxidation on the reaction temperature, solvent nature, and catalyst composition was examined.     

Anionic radical and protonated form of molecular ozone. A nonempirical calculation taking into account the electronic correlation

The different electronic states of ozone (¹A₁,³B₂,³A₂,³B₁, and 2¹A₁) were calculated by a nonempirical method in the basis 4–31 G (d, p) taking into account the electronic correlation according to the Meller-Plesset theory of a fourth order perturbation theory (MP4). The geometric structures of the ions O ₃ ^– and O₃H⁺ were calculated. The evaluation of the affinity to the proton for O₃ gave a value (P_A=6.8 eV) 1 eV lower than that for H₂O.Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Rubezhansk Branch, Dnepropetrovsk Institute of Chemical Technology. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 2, pp. 28–32, March–April, 1993.     

Ab initio calculations of interaction between the hydrated Fe2+ ion and molecular ozone

The ab initio LCAO-MO-SCF method with the STO-3G basis set is employed to calculate the electronic structure of different hydrated Fe²⁺ complexes. The general scheme of the interaction of ozone with Fe²⁺ (aq) is considered, whose first stage involves formation of an intermediate of the type of the ferryl ion FeO²⁺. Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Ruberzhansk Branch of Dnepropetrovsk Chemical-Technological Institute. Translated fromZhurnal Struktumoi Khimii, Vol. 35, No. 2, pp. 32–39, March–April, 1994. Translated by O. Kharlamova     

A Density Functional Study of Ozone and Oxygen Surface Structures on Ni(110)

The dissociative and molecular forms of O₃ adsorbed on nickel were studied by the density functional method (Becke3LYP exchange correlation functional). The energy profile of the ozone decomposition reaction (O₃)_gas (O₃)_ads (O₂)_ads+1/2O₂ on the Ni₁₀ surface cluster was calculated. As opposed to the weakly bound molecular form of oxygen on transition metals, ozone forms a tightly bound surface compound on the surface of nickel. It is attempted to evaluate the heat of oxygen adsorption on the defective surface of Ni using the model of the surface cluster Ni₁₃ with a vacancy . The positions of the surface nickel atoms before and after their interaction with the adsorbate were calculated. It is shown that substantial relaxation of the surface nickel atoms takes place in the course of adsorption. The possibility of stabilization of the molecular ozone-like form of oxygen on the surface of transition metals in conditions of high oxygen coating extent is discussed.     

Kinetics and Mechanism of 4-Nitrotoluene Oxidation with Ozone in an Acetic Acid Solution in the Presence of a Metal–Bromide Catalyst

The kinetics and mechanism of a reaction between ozone and 4-nitrotoluene in an acetic acid solution in the presence of a cobalt–bromide catalyst were studied at 100°. Under these conditions, 4-nitrobenzoic acid was the main reaction product (96.6%). The rate of oxidation exhibited a first order with respect to the substrate, ozone, and the catalyst and a zero order with respect to oxygen. The main stages of the catalytic cycle were considered. It is believed that the selective oxidation of 4-nitrotoluene at the methyl group in the presence of a catalyst occurs as a nonchain ion–radical process, in which the role of ozone is reduced to the generation of an active catalyst species (Co³⁺Br^– Co²⁺Br^·). This species involves 4-nitrotoluene in the oxidation process at a high rate.     

Density functional calculation for ozone-ethylene complexes

The density functional method (exchange correlation functional Becke3LYP) is used to calculate the potential energy profiles for the reaction of ozone with ethylene. It is shown that “direct” epoxidation of the C = C double bond demands high activation energy and is unlikely for both themwchemical and photochemical reactions of ozonolysis. Translated fromZhumal Struktumoi Khimii, Vol. 41, No. 2, pp. 240–247,     

Use of Ozone for Preparing 4-Nitrobenzoic Acid in a Closed Process Cycle

The possibility of preparing 4-nitrobenzoic acid in a closed process cycle by oxidation of 4-nitrotoluene with an ozone-air mixture was examined. The optimal conditions of oxidation with multiple use of mother liquors were found, and the conditions for crystallization of 4-nitrobenzoic acid from the reaction mixture were determined. The effects of water, acetic anhydride, and catalyst on the oxidation performed in mother liquors after filtration of the target product were examined.     

Molecular ozone-water complex.ab initio calculation with inclusion of electron correlation

The geometrical and electronic structure of different molecular O₃–H₂O complexes has been calculated by the ab initio method in the 4–31G (d, p) basis set with inclusion of electron correlation according to the Möller-Plesset fourth-order perturbation theory (MP4). It has been shown that the geometrical structure of the experimentally observed hydrogen-bonded complex is mainly determined by the entropy (rather than energy) effect, and is characterized by an almost free internal rotation of the H₂O molecule.Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Ruberzhansk Department of Dnepropetrovsk Chemical Technological Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 3, pp. 26–30, May–June 1993.Translated by L. Smolina     

A zero-discharge procedure for production of urea-formaldehyde resins

A zero-discharge procedure was suggested for preparing urea-formaldehyde resins by poly-condensation of urea, formaldehyde, and dimethylolurea at variable pH, with urea added continuously or in a single portion.