Masters Theses

Date of Award

5-2000

Degree Type

Thesis

Degree Name

Master of Science

Major

Chemistry

Major Professor

John E. Bartmess

Committee Members

Robert M. Compton

Abstract

Part 1 of this thesis involves updating a solution calorimeter to improve its ability to acquire data. This was accomplished by interfacing the calorimeter to a computer via a program written with LabVIEW software. Once this phase of the project was completed successfully, the newly improved calorimeter was then used to measure the heats of solution of both the D- and L- sodium bromate crystals. It was hoped that a measurable difference in the energy involved with their dissolving in water would help to provide information on chirality, especially as it exists in nature in biomolecules. These experiments proved to be more difficult to achieve consistent results from than was expected, while a measurable difference in the heats of solution was found, the values lack precision. Further investigation is required to attempt to confirm these results once the source of the irreproducibility is discovered and corrected. An irregularity in the crystallization of the sodium bromate is suspected as the source of the anomalies

Part 2 of this thesis deals with the study of the gas phase acidities of the long chain carboxylic acids (1-butanoic acid through 1-nonanoic acid) using ion cyclotron resonance mass spectrometry. The C-2 through C-6 straight chain acids are being repeated from previous experiments to insure the validity of the measurements for the C-7, C-8, and C-9 carbon chain acids, which have not been measured previously. A major experimental concern which was recurrent in this work involved the difference in volatility of the compounds. The difference in boiling points at the two extremes is 162°C for 1-butanoic acid and 254°C for 1-nonanoic acid Since intensity ratios were the center of interest in these experiments, care had to be taken to make sure that these ratios were due to the relative acidities of the acids and not to a difference in volatility. The trend was found to be the same among the shorter chained carboxylic acids (up to hexanoic acid) as was previously found, but a reversal occurs past hexanoic acid. There is a monotonic weakening as the chain gets longer, caused by increased importance of such thermodynamic properties as the enthalpy and entropy involved. It is also believed that this weakening is related to the longer chains' abilities to cyclize and form a coil with the alkyl end being attracted to the negative charge on the carboxylate anion.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS