Production of Hydrogen Peroxide in Liquid CO₂. 3. Oxidation of CO₂-Philic Anthrahydroquinones

Abstract

Hydrogen peroxide is currently produced via the sequential hydrogenation and oxidation of a 2-alkylanthraquinone. Use of liquid CO2 as the process solvent could ameliorate several environmental and engineering problems inherent to the conventional process. Oxidation reactions of perfluoroether-functionalized anthrahydroquinones (FAQH2s) generated in situ from Pd-catalyzed hydrogenation of functionalized anthraquinones (FAQs) were conducted in a high-pressure batch reactor in liquid CO2. The reaction was found to be first order with respect to both O2 and FAQH2. We have also found that the reactivity of FAQH2 in the oxidation is not affected by the size of the “CO2-philic” tail or the nature of the linker between the aromatic rings and the CO2-philic tail. These results are correlated with our previous conclusions on the phase behavior of FAQs in CO2 and kinetic studies of hydrogenation of FAQs. Finally, an optimum structure of FAQ to be used in the process is proposed.

Kinetic Model of Gas‐Liquid‐Liquid Reactive Extraction for Production of Hydrogen Peroxide

“…The same kinetic law has also been presented by Hancu and Beckman [20] in studying the oxidation CO 2 -philic anthrahyddroquinones to produce hydrogen peroxide.…”

Effect of System Conditions for Biodiesel Production via Transesterification Using Carbon Dioxide–Methanol Mixtures in the Presence of a Heterogeneous Catalyst

“…Finally, the reduced viscosity and enhanced diffusivity in the oil-rich phase owing to swelling by CO 2 will also reduce transport resistance to (and within) the solid catalyst, further enhancing the overall rate. 62 These effects combine to produce a high rate of transesterification despite the presence of multiple phases.…”

“…Next, as hypothesized by Song et al , methanol transport across the interface (between oil-poor and oil-rich phases) will be enhanced by the presence of CO 2 (via its ability to lower interfacial tension; such lowering of transport resistance can entirely outweigh the potential advantages of a single phase system. Finally, the reduced viscosity and enhanced diffusivity in the oil-rich phase owing to swelling by CO 2 will also reduce transport resistance to (and within) the solid catalyst, further enhancing the overall rate . These effects combine to produce a high rate of transesterification despite the presence of multiple phases.…”

Epoxidation of allyl choride with molecular oxygen and 2-ethyl-anthrahydroquinone catalyzed by TS-1

“…The higher the initial concentration of HEAQ in the working solution was, the more viscous the working solution was. The transport of oxygen is the key step for the oxidation of anthrahydroquinone, which is first order with respect to oxygen and is independent of the concentration of HEAQ [22]. So it is considered that the viscous hydrogenated working solution restrained the transport of oxygen and then the oxidation of the anthrahydroquinone to produce H 2 O 2 .…”