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Title: The Dehydration of Aprotic Solvents by Pervaporation
Author: Chapman, Peter Dale
ISNI:       0000 0001 3529 3040
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2008
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The application of pervaporation to the dehydration of aprotic solvents was investigated in this study. The performance of a commercial membrane, Celfa CMC-VP-31, was evaluated for the dehydration of tetrahydrofuran (THF) and dimethylformamide (DMF). The membrane was demonstrated to successfully dehydrate THF and calculations of water and THF permeance performed. When the membrane was applied to the dehydration of DMF, delamination of the top selective layer was observed and thus the membrane was deemed unsuitable for DMF dehydration. ' Polyaniline (PAni) was identified as a suitable candidate polymer for the formation of an aprotic solvent stable hydrophilic pervaporation membrane. PAni was synthesised in the lab and preparation conditions optimised and scaled-up to produce polymer with consistent batch to batch properties, in suitable quantities, to fabricate���· membrane sheets with sufficient surface area for testing. Casting solutions comprising of 20 wt% PAni were stabilised using an amine, 4-methyl piperidine, to prevent gelation and cross-linking prior to casting. Membranes were cast on a polyester non-woven backing and phase inverted in water to produce an asymmetric membrane structure. Scanning Electron Microscopy was used to examine the structure of the membranes formed. The effects of thermal treatment on the membrane film and polymer were investigated by a number of analytical techniques in order to devise a suitable procedure for membrane stabilisation. Thermally cross-linked PAni membranes were demonstrated to be water selective and stable in THF, DMF, ethyl acetate and ethanol. Permeance correlations with temperature were constructed to describe the performance of the membrane discs tested during solvent dehydration and compared to experimental data. Transport across the membrane was reported to be solubility dominated for all of the solvent systems tested. Finally, an examination of the reproducibility of membrane performance was made and further tests performed, to better understand variations observed in membrane pervaporation performance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available