Date of Award
Master of Science (MS)
The controlled oxidation or dissolved leonarclite was carried out in a heated autoclave under elevated oxygen pressure. Oxiaation was carried out in oraer to increase the aciaity oi: leonaraite and obtain higher humic acid yields. The solvent was an aqueous solution of sodium hydroxide in the range of concentrations from l>o to Si-.-.. The reaction temperature was varied from 25°C to I25°C; the pressure was kept at 500 psig and reaction time was constant at one hour. The product was analyzed both for carooxyiie acid and for hydroxyl groups.
The Increase in carboxyl and hydroxyl groups was slight under the optimum reaction conditions studied. The optimum conditons were: for temperature, between 50°C ana 75°C, and for concentration, between 2% and 6%. However at the 4% caustic concentration level, there was no increase in carboxyl and hydroxyl groups between 50°C and 75°C. Higher temperatures and higher concentrations of caustic resulted in lower yields of humic acids either because decarboxylation occurred or because the acids became water soluble.
Purandare, Vijay R., "The Controlled Oxidation of Leonardite" (1966). Theses and Dissertations. 3963.