Using α-cyanostilbenes as Lewis acids, Lewis acidity scales have been established in the systems DMSO-ethanol and DMSO-methanol containing the appropriate 0.01M sodium alkoxide and in the system sodium methoxide-methanol. This scale, designated HR-, describes the ability of the solvent to add an alkoxide ion to an alkene. The HR- values range from 11.73 in methanol to 21.74 in 93.27 mole % DMSO in ethanol. The most acidic indicator used to establish the scale was α-cyano-2,4-dinitrostilbene with a pK of 12.73 in DMSO-methanol. The least acidic was α-cyano-3-trifluoromethylstilbene with a pK of 21.98 in DMSO-ethanol. The effects of substituents in the two aromatic rings of α-cyanostilbenes on the Lewis acidity of these compounds has been measured. Using Ϭ values, an average ρ of 2.2 was obtained for the β -phenyl ring in the various solvent systems studied. Using Ϭˉ values, the ρ for α-cyanostilbenes with substituents in the α-ring is 4.77 in DMSO-ethanol and 4.24 in DMSO-methanol. In the α-phenyl ring the 4-nitro group exhibits a greatly exalted sigma value (1.75). In order to compare the HR- and H_ scales in one system, the H_ scale has been established in sodium methoxide-methanol using various carbon acids as indicators. The two scales are nearly parallel. The rates of the base catalyzed isomerization of α-eyano-cis-stilbenes were found to correlate with the HR- function. Plots of the logarithms of the apparent first order rate constants (k₁) for the isomerization against the HR- values gave excellent straight lines with slopes ranging from 0.426 to 0.665. The slopes of these lines depend on the substituent present in the α-phenyl ring and on the solvent system. The slopes were shown to be a measure of how closely the transition state for the isomerization reaction resembles the carbanion formed by the equilibrium addition of alkoxide ion to an alkene. The effect of substituents on the rate of isomerization of α-cyano-cis-stilbenes has been determined. Using Ϭ values the ρ for substituents in the α-phenyl ring is 3.07 in DMSO-ethanol and 2.82 in DMSO-methanol. The activation parameters for the base catalyzed isomerization reaction have been determined in DMSO-methanol. The enthalpies of activation range from 14.3 to 16.7 kcal. mole⁻¹ and the entropies of activation range from -9.3 to -13.7 e.u. depending on the substituent. The base catalyzed isomerization of α-cyano-cis-stilbenes is first order in base and first order in reactant. The mechanism of this reaction is discussed in terms of the kinetic-acidity function correlation, the substituent effects, and the activation parameters. The reactions of 1,1-bis-(4-nitrophenyl)ethene and 4,4'-dinitrobenzophenone with hydroxide or alkoxide ions in DMSO are described. / Science, Faculty of / Chemistry, Department of / Graduate

No description available.

Thesis (licentiate)--Universität Bern, 1980. / Cover title. Includes bibliographical references (leaves i-ii).

Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 82-83.

Thesis (Ph. D.)--University of Michigan, 1922.

Thesis (M.S. in chemical engineering)--Washington State University, August 2005. / Includes bibliographical references.

Master of Science

Thesis (Ph. D.)--Institute of Paper Chemistry, 1964. / Includes bibliographical references (p. 49-51).

Thesis (M.S. in chemical engineering)--Washington State University, August 2005. / Includes bibliographical references.

An experimental test system was designed to simulate the operating conditions found in nonslagging coal gasifiers. The reaction products that form when refractory linings in coal gasifiers are exposed to alkali impurities (sodium or potassium) were experimentally determined. Analysis of selected physical and chemical properties of the reaction products, which typically form between the alkali and the refractory will lead to a better understanding of the mechanisms behind refractory failures associated with alkali attack. The reaction products sodium aluminate (Na₂O·Al₂O₃), N₂C₃A₅ (2Na₂O·3CaO·5A1₂O₃), nepheline (Na₂0·Al₂0₃·2SiO₂), potassium aluminate, (K₂Oâ·Al₂0₃), and kaliophilite (K₂O·Al₂0₃·2Si0₂) were synthesized and their solubility in water and coefficients of linear thermal expansion were: measured. Of the compounds tested, the formation of potassium aluminate would be the most detrimental to the gasifier lining. The linear thermal expansion of potassium aluminate was 2.05% from room temperature to 800°C, which was twice as large as the other compounds. Potassium aluminate also possessed the highest solubility in water which was 8.893/L at 90°C. / Master of Science