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Automated measurement of the kinetics of chemical reactions in ionic liquids

Chen, Zhuo (2006) Automated measurement of the kinetics of chemical reactions in ionic liquids. PhD thesis, University of Sheffield.

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Abstract

This thesis has presented research work carried out searching for an automated measurement technique for the kinetics of chemical reactions in ionic liquids. The aim has been to develop a microchannel reactor system (MCR) to allow reaction kinetics measurement, involving mixing, reaction and sampling, in a single chip rapidly, automatically and accurately. The difficulty of mixing ionic liquids on a microchannel system etched on a chip resulted from two problems; the high viscosity of the liquids together with the low diffusivity of reactant molecules within them, and the small feature size and hence low Reynolds number of flows in microchannels. In order to achieve a mixing time that is negligible compared to the reaction duration, special measures must be taken to accelerate the mixing process. As a result, different mixing schemes were discussed in the thesis, with CFD computations and experimental work. Comparisons were made between different types of mixers involving both their mixing uniformity and pressure drop. The conclusion drawn from the study has been that the folding network mixer was the most effective, and thus it was used in the reaction network of the MCR system. The MCR system (Mark I) has been designed and constructed by selecting and assembling apparatus for the control of pressure, fluid flow, product sampling and analysis. A programme was developed to control the sequence and time scale of each operation, and models are developed for the determination of operating procedure and conditions. Furthermore, measurement techniques were developed for the determination of fluid flow, measurement of species composition and assessment of mixing performance. To assess the system performance, a series of tests have been carried out with a non-reacting solution system, and in addition, kinetics measurement in ionic liquids have been attempted. Drawbacks have been found in the apparatus' behaviour and control technique. Further improvements have then been made on the design and operation of the system. Consequently, the Mark 11 design of the MCR system has been presented, of which a new reaction network was proposed and fabricated, and a set of modified procedures and conditions was presented. With the improved system performance and operating conditions, good repeatability of kinetics measurement has been achieved. The deviation of measurement of reaction kinetics with the MCR system (Mark 11) was estimated to be within 5%.

Item Type: Thesis (PhD)
Academic Units: The University of Sheffield > Faculty of Engineering (Sheffield)
Other academic unit: Department of Chemical and Process Engineering
Identification Number/EthosID: uk.bl.ethos.434490
Depositing User: EThOS Import Sheffield
Date Deposited: 29 Mar 2019 11:44
Last Modified: 29 Mar 2019 11:44
URI: http://etheses.whiterose.ac.uk/id/eprint/21799

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