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Title: Calorimetric studies of metal β-diketonates
Author: Schulz, Ronald Arthur
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1970
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Heats of solution at 25°C. for six trivalent metal beta-diketonates in benzene, acetone and chloroform, have been measured calorimetrically. These results show that the solution process is only slightly affected by changing the metal complex over the range of tris 2,4-pentanedione chelates, Macac[3] (M = Al, Cr, Mn, Fe, Co), including the gamma-substituted tris (3:methyl-2,4-pentanediono)aluminium(III), but that significant differences exist between solvents. On this basis, conclusions have been drawn regarding the heats of sublimation of the complexes, and tentative suggestions have been put forward regarding possible solvent interaction phenomena. In chloroform solutions, specific interaction involving two molecules of solvent held by hydrogen bonds has been postulated. Thermochemical measurements were carried out on a recording solution calorimeter, developed from a well-tested isothermal jacket design, using a 100 ml glass reaction vessel. The instrument incorporates a direct reading temperature sensing element made up of two chromel-constantan thermocouples connected in parallel. The thermostatically controlled water bath (+/- 0.001°C.) which provides environmental control for the isothermal jacket, has been utilised to stabilise all the temperature sensitive components of the thermocouple circuit, except the sensing junctions, which are housed in a re-entrant tube on the reaction vessel. The thermocouple output is applied to a high gain D.C. amplifier which displays the equivalent temperature (emf.) vs time curve for the calorimeter on a strip-chart recorder. Increased sensitivity has been achieved by using a precision microvolt source in the input circuit, to "back-off" most of the applied signal. Calibration is carried out electrically and reactions involving emf. changes of the order of 1.0 muV have been consistently measured to better than +/- 0.005 muV, i.e. equivalent to a resolution of 1 x 10[-4]°C. or 0.015 joules.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available