Organic liquid-phase oxidation

Ethylbenzene Hydroperoxide Process. Figure 4 shows the process flow sheet for production of propylene oxide and styrene via the use of ethylbenzene hydroperoxide (EBHP). Liquid-phase oxidation of ethylbenzene with air or oxygen occurs at 206—275 kPa (30—40 psia) and 140—150°C, and 2—2.5 h are required for a 10—15% conversion to the hydroperoxide. Recycle of an inert gas, such as nitrogen, is used to control reactor temperature. Impurities ia the ethylbenzene, such as water, are controlled to minimize decomposition of the hydroperoxide product and are sometimes added to enhance product formation. Selectivity to by-products include 8—10% acetophenone, 5—7% 1-phenylethanol, and <1% organic acids. EBHP is concentrated to 30—35% by distillation. The overhead ethylbenzene is recycled back to the oxidation reactor (170—172). 

The approach consists of a liquid-phase oxidation using OH Fenton radicals from H2O2 for detemplation [148-150]. The radicals oxidize the organic template into CO2 and H2O while the porosity of the material is developed. The proof-of-principle of this concept is discussed for two case studies. 

Plucinski, P., Bavykin, D., Kolaczkowski, S., and Lapkin, A. (2005) Liquid phase oxidation of organic feedstock in a compact multichannel reactor. Ind. Eng. Chem. Res., 44, 9683-9690. 

Oxidation of organic compounds by dioxygen is a phenomenon of exceptional importance in nature, technology, and life. The liquid-phase oxidation of hydrocarbons forms the basis of several efficient technological synthetic processes such as the production of phenol via cumene oxidation, cyclohexanone from cyclohexane, styrene oxide from ethylbenzene, etc. The intensive development of oxidative petrochemical processes was observed in 1950-1970. Free radicals participate in the oxidation of organic compounds. Oxidation occurs very often as a chain reaction. Hydroperoxides are formed as intermediates and accelerate oxidation. The chemistry of the liquid-phase oxidation of organic compounds is closely interwoven with free radical chemistry, chemistry of peroxides, kinetics of chain reactions, and polymer chemistry. 

Liquid-phase oxidation of organic compounds is performed in laboratories and technological installations at 300-500 K. Under these conditions, organic compounds are quite stable, and their decomposition with dissociation at the C—C bond and in the reaction of retrodispro-portionation... 

KA Zhavnerko. Liquid-Phase Oxidation of Cyclohexanol Initiated by Hydrogen Peroxide. Ph.D. thesis, Institute of Physical Organic Chemistry, Minsk, 1969, pp. 3-19 [in Russian]. 

AM Novak. Liquid-Phase Oxidation of Benzaldehyds and Tetrahydrobenzaldehydes and Cooxidation of Benzaldehydes with Organic Compounds. Thesis Dissertation, Institute Physical Organic Chemistry, Donetsk, 1979 [in Russian]. 

The following four types of heterogeneous catalysis in the liquid-phase oxidation of organic compounds were observed. 

EA Blumberg, YuD Norikov. Heterogeneous Catalysis and Inhibition of Reactions of Liquid-Phase Oxidation of Organic Compounds [Itogi Nauki i Tekhniki, Kinetika i Kataliz], vol 12. Moscow VINITI, 1984, pp 1-143 [in Russian],... 

Cyclic mechanisms of Chain Termination in the Liquid-Phase Oxidation of Organic Compounds... 

A parallel reactor system for liquid-liquid phase reactions such as oxidation reactions with H202 at ambient pressure was reported from hte Aktiengesellschaft. If compared with other chemistries, rather mild-reaction conditions (ambient pressure, moderate temperature) are often applied in liquid-phase oxidation for fine chemical production with terminal oxidants that can be dosed as liquids (e.g., aqueous H202 or organic peroxides). The reaction that was investigated was the partial oxidation of... 

Oxidative chain reactions of organic compounds are current targets of theoretical and experimental study. The kinetic theory of collisions has influenced research on liquid-phase oxidation. This has led to determining rate constants for chain initiation, branching, extension, and rupture and to establishing the influence of solvent, vessel wall, and other factors in the mechanism of individual reactions. Research on liquid-phase oxidation has led to studies on free radical mechanisms and the role of peroxides in their formation. 

Production of phenol and acetone is based on liquid-phase oxidation of isopropylbenzene. Synthetic fatty acids and fatty alcohols for producing surfactants, terephthalic, adipic, and acetic acids used in producing synthetic and artificial fibers, a variety of solvents for the petroleum and coatings industries—these and other important products are obtained by liquid-phase oxidation of organic compounds. Oxidation processes comprise many parallel and sequential macroscopic and unit (or very simple) stages. The active centers in oxidative chain reactions are various free radicals, differing in structure and in reactivity, so that the nomenclature of these labile particles is constantly changing as oxidation processes are clarified by the appearance in the reaction zone of products which are also involved in the complex mechanism of these chemical conversions. 

All the available data on the rate of liquid phase oxidation of coal have been taken in batch reactors. Interpreting this data is complicated by the homogeneous oxidation of the intermediate organic acids formed and the con-... 

The catalytic capability of Au in liquid-phase oxidation can be tuned to a wider scope by choosing the support, size of Au, alkaline(with or without) and solvents. The products changed dramatically, depending on the solvents reactant alone without solvent, water, nonpolar and polar organic solvents. 

Oxidation and extraction, that is, liquid-phase oxidation with organic peroxides followed by separation of the oxidized sulfur (oxidative desulfurization, ODS) [51-58]. 

---