Presented as thesis (Ph. D.)--University of Wisconsin--Madison, 1912. / Cover title. Reprinted from the Journal of the American Chemical Society, vol. XXXVI, no. 5 (May, 1914). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis--Wisconsin. / eContent provider-neutral record in process. Description based on print version record.

The proton magnetic resonance absorption has been measured in stearic acid, anhydrous sodium stearate and anhydrous potassium stearate. The temperature dependence of the widths and second moments of the proton magnetic resonance absorption lines of these compounds is discussed. The proton magnetic resonance absorption in the C-form of stearic acid has been measured between -188°C and the melting point. The results suggest that the methyl end groups may be free to rotate about their C₃ axes above -77°C and that pre-melting becomes significant above 40°C. The proton magnetic resonance absorption in anhydrous sodium stearate has been investigated between -182°C and 200°C. An abrupt change in the line width and second moment has been observed between 113°C and 114°C, the supercurd to subwaxy phase transition. The results suggest that, at temperatures below 114°C, the motion of the hydrocarbon chain portion of the sodium stearate molecule is chiefly one of oscillation or rotation about the chain longitudinal axis. The hydrocarbon chains may be free to move about other axes above 114°C, although the molecule as a whole retains a fixed position in the crystal lattice. The proton magnetic resonance absorption in anhydrous potassium stearate has been measured from -190°C to 182°C. Abrupt changes in the line width have been observed between 55°C and 62°C and at 171°C; these changes correspond to known phase transitions. The second moment results suggest that some torsional oscillation may occur about the longitudinal axes of the hydrocarbon chain portion of the potassium stearate molecule, at temperatures below 55°C. Above 62°C, contact between the molecules may have decreased enough to allow some lateral motion of the hydrocarbon chains. / Science, Faculty of / Chemistry, Department of / Graduate

Dietary linoleate enhances the development of mammary tumors while dietary stearate has a retarding effect. Since linoleate is a precursor of prostaglandin E2 and elevated levels of prostaglandin E2 have been shown to be associated with tumor development, levels of dietary linoleate directly influence the levels of prostaglandin E2 available for tumor development. The development of new tumor tissue also involves a high demand for fatty acids to be incorporated into cell membranes and this demand is for specific types of fatty acids to maintain the required membrane fluidity.Several enzymes play key roles in the synthesis and desaturation of the fatty acids which are converted to prostaglandins and are synthesized for membrane incorporation. Among these are fatty acid synthetase and linoloeyl coenzyme A desaturase. This study examined the activity of these two enzymes in liver tissue of mice maintained on test diets containing varying proportions of the fatty acids stearate and linoleate.Animals fed a high fat (15% of total) diet containing 13.1% stearate were found to have higher linoloeyl coenzyme A deeaturaae activity than animals fed a low fat diet or a high fat diet containing 11.3% linoleate diets. Animals fed the high fat, high stearate diet were found to have a higher fatty acid synthetase activity than animals fed either a low fat diet or the high fat, high linoleate diet.

Thesis (PhD.(Chemical Engineering)--University of Pretoria, 2005. / Includes bibliographical references.

A general discussion of melting and premelting is given. Crystal structures and phase transitions in the C-forms of stearic, palmitic, myristic and lauric acids and in anhydrous sodium stearate are also discussed. Simple theories of infrared and nuclear magnetic resonance spectrometry are presented. Experimental difficulties in the use of solid phase infrared spectra are discussed. A detailed study is made of the temperature behaviour of the infrared spectra of the fatty acids in the region from 750 to 700 cm¯¹ and over the range from about 70ºC below the melting points to about 20ºC above them. Three overlapping peaks of different intensity are resolved - 720 cm¯¹, about 727 cm¯¹, and a peak at higher frequency the position of which varies in the different acids. The complete disappearance of the 720 cm¯¹ band slightly below the melting point in each acid is taken to indicate a transition, not previously reported, to a disordered phase in which there is considerable molecular motion as evidenced by the phase's liquid-like spectra. The presence of three peaks in the region is discussed on the basis of a simple theoretical expression derived by Snyder for the position of fundamental methylene rocking vibrations. The crystallinities of the acids are estimated from an expression, based on the work of Stein and Sutherland, which involves the apparent integrated absorption intensities of the resolved 720 and 727 cm¯¹ bands. The extent of premelting is determined. Extensive premelting giving the spectra a liquid-like, but not completely liquid character is found to take place within about 2ºC of the melting point. The high resolution nuclear magnetic resonance spectra of anhydrous sodium stearate were taken at the limit of their experimental application. The spectra show, however, that the subwaxy, waxy, superwaxy and subneat phases of anhydrous sodium stearate form a structurally similar group (from about 120 to 235ºC) with liquid-crystalline properties, while the neat and melt phases also form a structurally similar group (from 235º C upwards) but with the properties of a liquid. The information indicates extensive premelting beginning in the vicinity of 120ºC, below which temperature the salt is essentially crystalline, which reaches a climax at 235ºC, above which temperature the salt is essentially liquid. / Science, Faculty of / Chemistry, Department of / Graduate

The subject of graduation theses is the facture of the enterpreneurial plan of succesor company Oleochem a.s. First part is engaged in the enterpreneurial plan in theoretical line and in the process of company's restructuralisation. The practical part of graduation theses creates the historical review of the development of company SETUZA a.s. including the process of its restructuralisation. The last part of work consists of chapters, which are engaged in organization structure, products, competitive environment, production, the purchase of raw materials, quality and financial plan. At the close of graduation theses are introduced the strong and weak spots, the risks and the opportunities of enterpreneurial plan.