Trona acids

Oxygen Functional Groups in Green River Oil-Shale Kerogen and Trona Acids... 

The present report gives the methods used and the data obtained for acid, ester, aldehyde, ketone, amide, hydroxyl, and ether functional groups in kero-gen and trona acids. These methods may be applicable also in studying coals and other carbonaceous materials. 

The x-ray scattering intensities for kerogen and trona acids were obtained with an XRD-5 diffractometer using zirconium-filtered Mo K alpha radiation. The experimental x-ray intensities were corrected for air scattering, polarization, and absorption and then converted, using data from chemical analysis, to express the scattering per carbon atom. 

The similarity of kerogen and trona acids is indicated by their elemental compositions shown in Table I. In both materials the carbon to oxygen ratio indicates the presence of considerable quantities of oxygen functional groups. 

Figure i. X-ray scattering intensities per carbon atom of trona acids and kerogen from Green River oil shale... 

Figure 2. Infrared spectra of trona acids and kerogen concentrate...

Table III. Ester Content of Kerogen and Trona Acids Based on Hydrolysis and Calcium Exchange...

Figure 3. Infrared spectra in the 5.5-6.5 micron region of trona acids and kerogen concentrates and derivatives of these materials...

Results of the acetylation test on kerogen and trona acids (Table VI) indicated the presence of 4.7% of the kerogen oxygen and 1.8% of the trona acid oxygen as hydroxyl groups. 

Irving Wender What is the origin of the term trona acids ... 

John I. Fester The organic acids that occur in a sodium carbonate-sodium bicarbonate brine are referred to as trona brine in wells drilled in the Green River formation in western Wyoming. Hence the name trona acids. 

Dr. Wender Has the number of double bonds in kerogen or in trona acids been determined ... 

Dr. Fester The acetylation method used would include phenolic hydroxyl. However, the total hydroxyl for kerogen was less than 5% of the total oxygen and less than 2% for trona acids. If present, phenolic hydroxyl would represent only a small part of the total oxygen. 

On the other hand, groundwater humates are characterized by low 0/C (0.3-0.4) atomic ratios and H/C ratios of around 1.0. This implies a kerogen or Trona acid origin or contamination by these materials. 

The 0/C ratio is the clearest indicator of humic types. Soil humic acid ratios cluster around 0.50 while soil fulvic acids center around 0.70. Aquatic humic acids are close to the soil ratio of 0.50 however, aquatic fulvic acids possess consistently lower ratios of around 0.60. The difference may reflect different extraction procedures or it may represent lower carbohydrate contents in the water environment (Thurman and Malcolm, 1983). Another indication of the effect of carbohydrate content on the 0/C ratio comes from the analysis of sediments (Ishiwatari 1975a). With increasing depth, the carbohydrate content of fulvates increases while the carbohydrate content of humates decreases. This is revealed by the changes in the 0/C ratios. These ratios may indicate serious contamination from other sources. Thus, groundwater humates show abnormally low 0/C ratios this may be due to contamination by kerogens or Trona acids. 

Fester, J. I. and Robinson, W. E. (1966). Oxygen functional groups in Green River oil shale kerogen and trona acids. Coal. Sci. (Adv. Chem. Ser.) 55, 22-24. 

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