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The thermal decomposition of ozone. Evidence of the existence of activated molecules in a chemical reaction. Possible limits for the heat of dissociation of oxygen

Citation

Wulf, Oliver Reynolds (1926) The thermal decomposition of ozone. Evidence of the existence of activated molecules in a chemical reaction. Possible limits for the heat of dissociation of oxygen. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-11042004-153821

Abstract

This research is being carried out to investigate as completely as possible the thermal rate of a simple chemical change in the gas phase, in order to make the reaction available as a tool for the general study of the mechanism of chemical reaction. This purpose can indeed be realized only when the complete mechanism of the reaction is understood.

A survey of the known gas reactions which possess an appreciable rate at convenient temperatures showed very few that offered possibilities. The decomposition of ozone, however, seemed to be an exception, possessing unusual opportunities, and it was therefore chosen. The reaction possesses the relative simplicity which is usually characteristic of decompositions. Whatever the mechanism might prove to be, in effect the change could apparently be only the reversion of two molecules of ozone into three of oxygen. The normal thermal rate of this change is convenient for measurement at 100°C, while at room temperature it is negligibly small. The walls of the containing vessel in general promote catalytic decomposition, but by suitable cleaning of the walls this can so far be eliminated that at 100° and above it can be neglected in comparison with homogeneous change.

Although a large number of experimental measurements have been made, and their results collected in this thesis, it is necessary to state here that the purpose of this work has not yet been accomplished. However, two further important results have been obtained. First, a critical survey of the work done up to this time on the reaction can now be made in a way impossible heretofore. Considering the remarkable apparent discordancy that existed among the previous investigations of this gas reaction, such a survey alone is felt to be of value. Secondly, observations made during the present research have indeed increased the importance of ultimately reaching a complete explanation of the mechanism of the reaction, because it has been found that the reaction will then lend itself to an effective way to several closely related studies.

In Part I there is given a critical survey of the work done up to the present time on this reaction. Part II contains the results of the present investigations using the “static method”, and Part III gives the results of a series of experiments performed to determine in particular the effect of the total gas pressure and of the partial pressure of oxygen upon the decomposition. Part IV contains the results of a series of experiments carried out at a higher temperature by the "dynamic method", which are believed to be leading to an explanation of the mechanism of the decomposition.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Tolman, Richard Chace
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1926
Record Number:CaltechETD:etd-11042004-153821
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-11042004-153821
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4403
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:04 Nov 2004
Last Modified:26 Dec 2012 03:08

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