Controlled multiphase oxidations for continuous manufacturing of fine chemicals

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Title: Controlled multiphase oxidations for continuous manufacturing of fine chemicals
Authors: Hii, KM
Loponova, KN
Deadman, BJ
Zhu, J
Reilly, C
Holdich, RG
Hellgardt, K
Item Type: Journal Article
Abstract: The feasibility of an integrated continuous biphasic oxidation process was studied, incorporating (i) electrochemical generation of an oxidant, (ii) membrane emulsification and an Oscillatory Flow Reactor (OFR) to facilitate mass-transfer in a biphasic reaction system and (iii) product extraction to enable regeneration of the oxidant. The biphasic, organic solvent-free dihydroxylation of styrene by ammonium peroxodisulfate solutions (including electrochemically generated peroxodisulfate) was investigated as a model reaction, both in batch and in an OFR. Heating of peroxodisulfate in a strongly acidic solution was demonstrated to be essential to generate the active oxidant (Caro’s acid). Membrane emulsification allowed mass-transfer limitations to be overcome, reducing the time scale of styrene oxidation from several hours in a conventional stirred tank reactor to less than 50 min in a dispersion cell. The influence of droplet size on overall reaction rate in emulsions was studied in detail using fast image capturing technology. Generation of unstable emulsions was also demonstrated during the oxidation in OFR and product yields >70% were obtained. However, the high-frequency/high-displacement oscillations necessary for generation of fine droplets violated the plug flow regime. Membrane emulsification was successfully integrated with the OFR to perform biphasic oxidations. It was possible to operate the OFR/cross-flow membrane assembly in plug flow regime at some oscillatory conditions with comparable overall oxidation rates. No mass-transfer limitations were observed for droplets <60 μm. Finally, the continuous post-reaction separation was demonstrated in a single OFR extraction unit to enable continuous regeneration of the oxidant.
Issue Date: 5-May-2017
Date of Acceptance: 5-May-2017
URI: http://hdl.handle.net/10044/1/48681
DOI: https://dx.doi.org/10.1016/j.cej.2017.05.017
ISSN: 0300-9467
Publisher: Elsvier
Start Page: 220
End Page: 230
Journal / Book Title: Chemical Engineering Journal
Volume: 329
Copyright Statement: © 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC-BY license (http://creativecommons.org/licenses/by/4.0/).
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Funder's Grant Number: EP/L012278/1
Keywords: Science & Technology
Technology
Engineering, Environmental
Engineering, Chemical
Engineering
Biphasic liquid-liquid oxidation
Process intensification
Flow chemistry
Membrane emulsification
Oscillatory Flow Reactor
Electrochemistry
TIME DISTRIBUTION MEASUREMENTS
PROCESS INTENSIFICATION
MEMBRANE EMULSIFICATION
BAFFLED REACTOR
FLOW
PERSULFATE
DISPERSION
CHEMISTRY
MECHANISM
KINETICS
0904 Chemical Engineering
Chemical Engineering
Publication Status: Published
Open Access location: http://www.sciencedirect.com/science/article/pii/S1385894717307593
Appears in Collections:Faculty of Engineering
Chemistry
Catalysis and Advanced Materials
National Heart and Lung Institute
Chemical Engineering
Faculty of Medicine
Faculty of Natural Sciences



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