Enhanced production of ethyl pyruvate using gas–liquid slug flow in microchannel

Abstract

a b s t r a c tThe use of a gas-liquid slug flow in a microreactor has several advantages such as a large surface area for contacting gas and liquid phases and circulation flow inside slugs. These advantages accelerate the mass transfer between the two phases, resulting in a high concentration of dissolved gas. The enhanced mass transfer is useful in carrying out liquid phase oxidation that uses oxygen gas as the oxidizing agent. The gas-liquid slug flow in a microreactor system is applied to the oxidation of ethyl lactate using an oxyvanadium species for producing ethyl pyruvate. The reactor system includes two T-shaped micromixers: one for mixing the substrate with a catalyst solution and the other for generating slug flow by the addition of oxygen. The oxidation reaction proceeds right after the slug flow is generated in the second mixer, because the substrate and the catalyst mix rapidly in the first micromixer. Moreover, a high concentration of dissolved oxygen due to improved mass transfer in slug flow increases the oxidation reaction rate. Therefore, compared to a batch reaction, the synthesis using slug flow provides high yields of ethyl pyruvate per unit time and achieves satisfactory productivity at the reaction temperature of 323 K, which is lower than that employed in conventional syntheses. The proposed system enables the production of ethyl pyruvate using a simple reactor setup with reduced energy consumption.

Rapid Synthesis of Poly(methyl methacrylate) Particles with High Molecular Weight by Soap‐Free Emulsion Polymerization Using Water‐in‐Oil Slug Flow

“…The thin liquid films prevent the viscous polymer solution from adhering to the channel wall and clogging of the channel . Furthermore, it is well‐known that internal circulation flow generated in a slug flow enhances the mixing of reactants in each slug and facilitates mass transfer between the liquid–liquid interfaces . Although a few studies using a slug flow for polymerization have been reported, to the best of our knowledge, there are no studies showing the production of polymer particles using a slug flow.…”

Highly Selective Oxidation of Ethyl Lactate to Ethyl Pyruvate Catalyzed by Mesoporous Vanadia–Titania

“… 15 Yasukawa et al studied the oxidation of ethyl lactate to pyruvate over various homogeneous vanadium compounds in a gas–liquid microflow system. 16 They found that vanadium oxytrichloride (VOCl 3 ) gave the highest yield (31%) at room temperature, making it 5 times as active as V 2 O 5 . 17 Considering catalyst recovery and product purification, solid vanadium catalysts are preferable.…”

Formation characteristics of Taylor bubbles in a microchannel with a converging shape mixing junction

“…The recirculation in the liquid slugs improves radial mixing [12,13]. Thus, microreactors operated under Taylor flow have found great use in various chemical processes such as nanoparticle synthesis [14][15][16][17] and homogeneously/heterogeneously catalyzed gas-liquid reactions [18][19][20].…”