Liquid Phase Oxidation Of Organic Compounds Research Articles

Catalysts for Liquid-Phase Oxidation of Organic Compounds with Hydrogen Peroxide: Homogeneous and Phase Transfer Systems

Catalysts for Liquid-Phase Oxidation of Organic Compounds with Hydrogen Peroxide: Homogeneous and Phase Transfer Systems

Catalysts for Liquid-Phase Oxidation of Organic Compounds by Hydrogen Peroxide: Homogeneous and Phase-Transfer Systems

The review presents a comparative analysis of promising homogeneous metal complex catalysts and presents the results of studies on the synthesis and determination of the structural characteristics of effective catalysts for the oxidation of organic compounds with hydrogen peroxide – Q3{PO4[WO(O2)2]4} (Q is a quaternary ammonium cation) – using methods EXAFS, SAXS, NMR, Raman and IR spectroscopy. The possibilities of using bifunctional homogeneous peroxopolyoxo complexes of metals in combination with organic cations having quaternized nitrogen under the conditions of interfacial catalysis are considered, using examples of reactions of oxidation of various classes of organic compounds with hydrogen peroxide to obtain popular products – aliphatic and aromatic epoxides, mono- and dicarboxylic acids, as well as biologically active compounds for medical and agro-industrial purposes.

Development of a Detailed Kinetic Model for the Oxidation of n-Butane in the Liquid Phase.

The chemistry underlying liquid-phase oxidation of organic compounds, the main cause of their aging, is characterized by a free-radical chain reaction mechanism. The rigorous simulation of these phenomena requires the use of detailed kinetic models that contain thousands of species and reactions. The development of such models for the liquid phase remains a challenge as solvent-dependent thermokinetic parameters have to be provided for all the species and reactions of the model. Therefore, accurate and high-throughput methods to generate these data are required. In this work, we propose new methods to generate these data, and we apply them for the development of a detailed chemical kinetic model for n-butane autoxidation, which is then validated against literature data. Our approach for model development is based on the work of Jalan et al. [J. Phys. Chem. B 2013, 117, 2955-2970] who used Gibbs free energies of solvation [ΔsolvG(T)] to correct the data of the gas-phase kinetic model. In our approach, an equation of state (EoS) is used to compute ΔsolvG as a function of temperature for all the chemical species in the mechanism. Currently, ΔsolvG(T) of free radicals cannot be computed with an EoS and it was calculated for their parent molecule (H-atom added on the radical site). Theoretical calculations with the implicit solvent model were performed to quantify the impact of this assumption and showed that it is acceptable for radicals in n-butane and probably in all n-alkanes. New rate rules were proposed for the most important reactions of the model, based on theoretical calculations and the literature data. The developed detailed kinetic model for n-butane autoxidation is the first proposed model in the literature and was validated against the experimental data from the literature. Simulations showed that the main autoxidation products, sec-butyl hydroperoxides and 2-butanol, are produced from H-abstractions from n-butane by sec-C4H9OO radicals and the C4H9OO + C4H9OO reaction, respectively. The uncertainty of the product ratio ("butanone + 2-butanol"/"2-butoxy + 2-butoxy") of the latter reaction remains high in the literature, and our simulations suggest a 1:1 ratio in n-butane solvent.

The kinetics, catalysis and inhibition of the Baeyer—Villiger reaction in the processes of liquid-phase oxidation of organic compounds

Literary data on kinetics, catalysis and inhibition of the oxidation reaction of carbonyl compounds with peroxy acids according to the Baeyer—Villiger reaction under aerobic liquidphase oxidation conditions have been considered and discussed. The main reaction channel involves a reversible formation of α-hydroxyperoxy ester and its rearrangement to an ester or a lactone. In the case of homolytic decomposition of α-hydroxyperoxy ester no esters are formed. At all steps the formation and transformation of α-hydroxyperoxy ester are catalyzed by carboxylic acids. The possibility of formation of the second intermediate, presumably dioxirane, is shown. Catalysts of the oxidation processes such as variable-valency metal salts influence the kinetics at all steps in the Baeyer—Villiger reaction. Inhibition of ester formation in the presence of cobalt and manganese salts is associated with catalysis of homolytic decomposition of peroxy acid and α-hydroxyperoxy ester.

The role of the Baeyer–Villiger reaction in the liquid-phase oxidation of organic compounds

The data on the composition of ester products formed in the Baeyer–Villiger reaction in the liquid-phase oxidation of organic compounds with molecular oxygen, on production channel of peroxy acids, as well as on the influence of a carbonyl compound structure on its reactivity in reactions with peroxy acids have been classified and considered. The Baeyer–Villiger reaction was shown to be the main source of accessory primary alcohol esters and lactones in industrial processes of aerobic oxidation of cyclohexane and paraffin hydrocarbons.

Catalytic properties of the polyoxometalate [Ti2(OH)2As2W19O67(H2O)]8− in selective oxidations with hydrogen peroxide

The catalytic properties of the sandwich polyoxometalate [Ti2(OH)2As2W19O67(H2O)]8−, which contains two (B-α-AsIIIW9O33) fragments linked together by a “belt” consisting of one octahedral WO(H2O)4+ and two square-pyramidal Ti(OH)3+ groups, have been investigated in the selective liquid-phase oxidation of organic compounds by aqueous hydrogen peroxide. The polyoxometalate shows high catalytic activity and selectivity in the oxidation of alkenes, alcohols, diols, and thioethers. The composition of the reaction products indicates that hydrogen peroxide is activated via a heterolytic mechanism.

Handbook of free radical initiators

Preface. Symbols and Abbreviations. PART I: INITIATORS. Chapter 1. Mechanism of Decomposition of Initiators. 1.1 Introduction. 1.2 Nonconcerted Unimolecular Decomposition. 1.3 Concerted Fragmentation of Initiators. 1.4 Anchimerically Assisted Decomposition of Peroxides. 1.5 Decay of Initiators to Free Radicals and Molecular Products. 1.6 Chain Decomposition of Initiators. References. Chapter 2. Cage Effect. 2.1 Introduction. 2.2 Experimental Evidence for the Cage Effect. 2.3 Mechanistic Schemes of Cage Effect. 2.4 Cage Effect in Solid Polymers. References. Chapter 3. Methods of Study of Initiator Decomposition and Free Radical Generation. 3.1 Kinetic Decay of Initiator (KDI). 3.2 Kinetic Product Formation (KPF). 3.3 Acceptors of Free Radicals (AFR). 3.4 Kinetic Chain Initiated Reaction (KIR). 3.5 Chemiluminescence (CL) Method. References. Chapter 4. Dialkyl Peroxides and Hydroperoxides. 4.1 Dialkyl Peroxides. 4.2 Hydroperoxides and Peracids. References. Chapter 5. Diacyl Peroxides, Peroxy Esters, Polyatomic, and Organometallic Peroxides. 5.1 Diacyl Peroxides. 5.2 Peroxy Esters. 5.3 Decomposition of Polyatomic Peroxides. 5.4 Organometallic Peroxides. References. Chapter 6. Organic Polyoxides. 6.1 Dialkyl Trioxides. 6.2 Hydrotrioxides. 6.3 Tetroxides. References. Chapter 7. Azo Compounds. 7.1 Synthesis and Structure of Azo Compounds. 7.2 Thermochemistry of Azo Compounds. 7.3 Decomposition of Azo Compounds. References. Chapter 8. Compounds with Weak C-C, N-N, C-N and N-O Bonds. 8.1 Polyphenylhydrocarbons. 8.2 Substituted Hydrazines. 8.3 Alkoxyamines. 8.4 Nitro Compounds. 8.5 Nitrates and Nitrites. 8.6 Disulfides and Polysulfides. 8.7 Organometallic Compounds. References. PART II: BIMOLECULAR REACTIONS OF FREE RADICAL GENERATION. Chapter 9. Parabolic Model of Bimolecular Homolytic Reaction. 9.1 Introduction. 9.2 Principles for the Parabolic Model of Bimolecular Homolytic Reaction. 9.3 Parameters of Bimolecular Homolytic Reaction in the Parabolic Model. References. Chapter 10. Bimolecular and Trimolecular Reactions of Free Radical Generation by Dioxygen. 10.1 Reaction of Dioxygen with C-H Bonds of Organic Compounds. 10.2 Reaction of Dioxygen with the Double Bond of Olefins. 10.3 Trimolecular Reaction of Radical Initiation by Dioxygen. References. Chapter 11. Bimolecular Reactions of Free Radical Generation by Ozone. 11.1 Initiation of Radicals by Ozone Reactions. 11.2 Chain Reactions of Ozone Decomposition. References. Chapter 12. Bimolecular Reactions of Hydroperoxides with Free Radical Generation. 12.1 Bimolecular Decomposition of Hydroperoxides. 12.2 Bimolecular Reactions of Hydroperoxides with a pi-Bond to Olefins. 12.3 Bimolecular Reactions of Hydroperoxides with C-H, N-H, and O-H Bonds of Organic Compounds. 12.4 Acid Catalysis for Homolytic Reactions of Hydroperoxides. 12.5 Reaction of Peroxides with Amines. References. Chapter 13. Free Radical Generation by Olefins. 13.1 Reactions of Retrodisproportionation. 13.2 Chain Initiation in Thermal Radical Polymerization. References. Chapter 14. Free Radicals Generation by Haloid Molecules and Nitrogen Dioxide. 14.1 Reactions of Fluorine Compounds. 14.2 Reactions of Dichlorine and Other Chlorine Compounds. 14.3 Initiation by Nitrogen Dioxide. References. Chapter 15. Free Radical Generation by Reactions of Ions with Molecules. 15.1 Decomposition of Hydrogen Peroxide Catalyzed by Transition Metal Ions. 15.2 Catalysis by Ions and Complexes of Transition Metals in Liquid-Phase Oxidation of Organic Compounds. 15.3 Reactions of Free Radicals with Transition Metal Ions. 15.4 Oxidation of Transition Metal Ions by Dioxygen. 15.5 Oxidation of Organic Compounds by Transition Metal Ions. 15.6 Reduction of Peroxides by Radical Anions. References. PART III: REACTIONS OF FREE RADICALS. Chapter 16. Isomerization and Decomposition of Free Radicals. 16.1 Intramolecular Abstraction of Hydrogen Atom. 16.2 Cyclization of Free Radicals. 16.3 Decyclization of Cyclic Radicals. 16.4 Fragmentation of Free Radicals. References. Chapter 17. Free Radical Abstraction Reactions. 17.1 Classification of Radical Abstraction Reactions. 17.2 Enthalpy of Reaction. 17.3 Force Constants of Reacting Bonds. 17.4 Triplet Repulsion. 17.5 Electron Affinity of Atoms in Reaction Center. 17.6 Repulsion of Atoms Forming the Reaction Center. 17.7 Influence of pi-Bonds in the Vicinity of the Reaction Center. 17.8 Steric Effect. 17.9 Polar Effect in Radical Reactions. 17.10 Effect of Multidipole Interaction. 17.11 Solvating Effect. References. Chapter 18. Free Radical Reactions of Hydrogen Transfer and Substitution. 18.1 Reactions of Hydrogen Atom Transfer from a Free Radical to a Molecule. 18.2 Free Radical Substitution Reactions. 18.3 Reaction of Peroxides with Ketyl Radicals. References. Chapter 19. Free Radical Addition. 19.1 Enthalpy and Entropy of Free Radical Addition. 19.2 Empirical Correlation Equations. 19.3 Quantum Chemical Calculations for the Activation Energy. 19.4 Parabolic Model of Radical Addition. 19.5 Contribution of Enthalpy for an Addition Reaction to Its Activation Energy. 19.6 Force Constants of Reacting Bonds. 19.7 Triplet Repulsion in the Transition State of Addition Reactions. 19.8 Influence of Neighboring pi-Bonds on the Activation Energy of Radical Addition. 19.9 Role of the Radius of the Atom Bearing the Free Valence. 19.10 Interaction of Two Polar Groups. 19.11 Multidipole Interaction in Addition Reactions. 19.12 Steric Hindrance. 19.13 Addition of Alkyl Radicals to Dioxygen. References. Chapter 20. Recombination and Disproportionation of Free Radicals. 20.1 Alkyl Radicals. 20.2 Macroradicals. 20.3 Peroxyl Radicals. References. Index.

Determination of the kinetic significance of elementary steps in the reaction of ethylbenzene oxidation inhibited by para-substituted phenols: Choice of an effective antioxidant

A conceivable method (“value” method) for analyzing the reaction kinetics models of inhibited liquid-phase oxidation of organic compounds was considered. A procedure for the numerical calculations of the molecular structure parameters of an inhibitor and an inhibitor concentration that results in a maximum inhibition of the reaction was presented. In the kinetic model of a chain reaction of liquid-phase ethylbenzene oxidation in the presence of a para-methylphenol inhibitor, the dynamics of contributions from individual steps was calculated. This allowed us to simplify the reaction mechanism. The inhibition of the oxidation reaction due to reactions with the participation of a phenoxyl radical was found to occur under conditions of the quasi-equilibrium

Book Review: Inhibition of Chain Reactions by E.T. Denisov and V.V. Azatyan (London: Gordon and Breach, 2000, 337 pp.)

In 2000, Gordon and Breach Science Publishers published a monograph Inhibition of Chain Reactions by E.T. Denisov and V.V. Azatyan, who are experts in chemical kinetics. The monograph is devoted to one of the most topical problems of the theory and practice of chain processes. The book considers a wide variety of different chain processes, including nonbranched chain reactions (radical polymerization, hydrocarbon cracking, and halogenation), the liquid-phase oxidation of organic compounds and polymers, and branched chain combustion and explosion. Numerous experimental data on the kinetics and mechanism of the inhibition of chain processes involving different chains are systematized and analyzed.

Route of autooxidation of organic compounds through a metal ion and bromide catalysis

Liquid-phase oxidation of organic compounds is normally an autocatalytic process and proceeds by a branched-chain mechanism through intermediate formation of peroxides. Decomposition of peroxides into free radicals ensures branching of the chain and consequently autoacceleration of the reaction. This is a study of such an oxidation using a cobalt-bromide catalysts. The reaction and its kinetics are thoroughly investigated, and a mechanism is reported.