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Title: The kinetics of hydrolysis and the electronic absorption spectra of some sterically hindered basic dyes
Author: Giles, David Eric
ISNI:       0000 0001 3498 8254
Awarding Body: Preston Polytechnic
Current Institution: University of Central Lancashire
Date of Award: 1982
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A comprehensive series of derivatives of Malachite Green substituted in the phenyl ring with silicon, phosphorus, sulphur, nitrdgen or oxygen containing groups have been synthesised. Their absorption spectra have been measured in 98% acetic acid solution and compared with that of Malachite Green. The variations in Amax and E max for both the Xand y-band absorbances have been explained in terms of electronic and steric effects of the substituent groups. Substituent constants have been obtained for the above groups from the appropriate Hainmett plot. These values have been compared with previously published literature values. The 1 H n.m.r. spectrum of the 2-formyl derivative of Malachite Green methyl ether is notable for the large upheld shift of the formyl proton. This has been explained in terms of the configuration of the molecule and associated shielding effects. The alkaline hydrolyses of Malachite Green and a range of the above 3- and 1+-substituted derivatives have been studied. The values of k2 , the rate constant for the reaction of dye cation with hydroxide ions, have been corre1atedwith Hammett a' constants. Differences between the substituent constants derived by kinetic and spectroscopic methods and between.somel literature values have been highlighted. The values of 1 < 2 and k , the rate constant for the reaction of the dye cation with water molecules, obtained for Malachite Green show good agreement with values pbtained in previbus studies. The kinetic parameters A 0 and A ' have been obtained for each dye and those for Malachite Green are in good agreement with previous results.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Chemistry