Physical Sciences and Mathematics Commons^™

Acidities In Ethanol/Water Solvents;The Pka Of Hf., Raymond M. Merrill

Chemistry and Chemical Biology ETDs

The acidity of hydrofluoric acid in mixed ethanol/ water solvent systems was studied by determining the pKa of HF in a number of different ethanol concentrations. The effect of changing temperature on the acidity of HF in these media was also examined.

The pKa's were determined using a lanthanum fluoride membrane Fluoride Specific Ion Electrode and a glass pH electrode versus the same reference electrode. The method eliminates the need to determine liquid junction potentials. By determining the pKa for HF in each ethanol/water mixture, at a number of different temperatures, thermodynamic parameters, such as free energy, enthalpy, entropy, and …

Synthesis Of Derivatives Of Pyrido [3,4-D]Pyridazines, Diane (D'Ottavio) Martin

Chemistry and Chemical Biology ETDs

The current interest in the biological activity of certain 1 ,4-disubstituted pyrido[2 ,3-d]pyridazines prompted the investigation of various derivatives of the isomeric pyrido[3,4-d]pyridazine ring system. Thus, 1,4 ­ dichloro[3,4-d]pyridazine was treated with thiourea and the intermediate thiouronium salt hydrolyzed to give pyrido[3, 4-d]pyridazine-1,4(2H,3H)-dithione which was subsequently alkylated to give 1,4-bis(alkylthio)pyrido­[3,4-d]pyridazines. On the other hand, 1,4-bis(arylthio)­pyrido[3,4-d]pyridazines were prepared by the reaction of 1,4-dichloropyrido[3,4-d]pyridazine with various substituted thiophenols. Furthermore, treatment of 1,4-dichloropyrido[3,4-d]­pyridazine with a variety of substituted anilines gave the corresponding 1,4-disubstituted aniline derivatives, whereas reaction with alkylamines afforded only the 1(4)-chloro-4(1)-alkylaminopyrido[3,4-d]pyridazines. When 1-chloropyrido[3,4-d]pyridazine-4(3H)-one or 4-chloropyrido[3,4-d]pyridazine-1(2H)-one was treated with hydrazine, the corresponding …

Acid-Base Titrations In Sulfolane., Francine O. Lawrence

Chemistry and Chemical Biology ETDs

A study of the solvent effects of sulfolane (tetrahydrothiophene 1,1-dioxide, tetramethylene sulfone) upon a series of acids and several bases has been conducted. A procedure is presented for purifying sulfolane which results in a solvent of very low water content (5 x 10^-4 M ) and very few impurities, as shown by its cooling curve. Potentiometric and conductometric measurements of additions of acids and bases to purified sulfolane and of various acid-base titrations were made. The series of carboxylic acids included benzoic, orthomethoxybenzoic, and three different monochlorobenzoic acids. The bases investigated included sodium methoxide, pyridine, and diphenylguanidine. Interpretation of the …

Continuous Wave Co2 Laser Degradation And Mass Spectrometric Analysis Of Organic Polymers., Stanley G. Coloff

Chemistry and Chemical Biology ETDs

Previous laser-mass spectrometer and laser-gas-chromatographic instruments for study of organic polymer degradation have used high power pulsed lasers (ruby, Nd-glass) which limit sample characterization due to extensive fragmentation.

A new experimental technique has been developed for high temperature pyrolysis and rapid analysis of organic polymers. The experimental technique combines a low power continuous wave CO2 laser for sample pyrolysis and a time-of-flight mass spectrometer to analyze degradation products. The laser built for use in this study was a continuous flow CO2 gas-molecular laser excited by high voltage direct current with maximum power of 10 watts at a wavelength of 10600 …