Water soluble hydrocarbons, analysis

Analysis of PBC Oil for Water-Soluble Hydrocarbons. A solution of 40 mg PBC in 1 mL hexane was separated into saturate and aromatic fractions as described above. The saturate fraction was diluted to 50 mL with hexane and the aromatic fraction was diluted to 100 mL with 20%... 

The partitioning of fuel oil no. 2 and kerosene into drinking water after 17 hours of incubation resulted in only 1.0% of the fuel oil and 0.7% of the kerosene being dissolved in the water. Further analysis of these fuels indicated that although each compound contains approximately 50% aliphatic hydrocarbons (by weight percent), the water-soluble fractions contained primarily aromatic constituents (>93%) including benzenes and naphthalenes as shown below (Coleman et al. 1984) ... 

To investigate further the chemical characteristics of potential alternative emulsifiers, the water-soluble fractions (WSFs) of each emulsifier were measured [61]. The samples were analyzed for total recovered hydrocarbons (TRH) in the C10-C36 region and PAHs [3, 62]. The chemical analysis of the emulsifier WSFs did not detect PAHs. Consequently, in the future, use of low-fluorescence emulsifiers in the reformulated Syndrill 80 20 (Mod) will allow the measurement of biliary fluorescence as a biomarker of exposure in field-caught fish attracted to cutting piles, with any detected fluorescence eliminating the drilling mud Syndrill 80 20 (Mod) as a source of fluorescent metabolites in the biliary secretions. 

The effect of trace contaminants on the reaction has been investigated carefully. All uncondensed effiuent gases were recycled to the reactor, except for the amounts present in the streams taken off for analysis or flashed upon depressuring of the organic phase. Aqueous phase from the separator containing the water soluble by-products has been used as the water feed to the reactor. Hydrogen chloride containing chlorinated hydrocarbons and acetylene was used in all operations. In addition, certain possible impurities were tested for their effect on the kinetics and selectivity of the process. Paraffins, carbon monoxide, sulfide, carbon dioxide, alkali, and alkaline earth metals were found to be chemically inert. Olefins, diolefins and acetylenic compounds are chlorinated to the expected products. No deleterious effects of by-product recycle were observed even when some of the main by-products were added extraneously. 

Oils. Water can be equilibrated with an excess of oil, and the water subsequently analyzed for dissolved hydrocarbons. Individual hydrocarbons at equilibrium in water have concentrations dependent on their mole fractions in the oil and their solubilities in water. Therefore, analysis of the water permits calculation of the amount of each soluble hydrocarbon in the oil phase. 

The studies described above give evidence that the XAD-2 method provides a useful determination of the hydrocarbon components in dilute seawater-oil suspensions. The quantity of "total oil reported in Table I is in sharp contrast to the total hydrocarbons found in the water by the combined helium extraction/XAD extraction techniques. The discrepancy between total oil by IR and hydrocarbons found in water by component analysis was previously reported (5,11) and can be explained by the low contribution to the IR absorbance at 2927 cm 1 of the soluble aromatic constituents relative to the saturate hydrocarbons. The difference between IR analytical result and component analysis by GC becomes much greater in the filtered systems, where the total hydrocarbons found are three times that reported by the IR method. It is clear that the IR analytical technique is only useful in systems where there is a preponderance of particulate, bituminous petroleum or where it is used as a monitoring tool. It provides no information about actual levels of hydrocarbons in systems where there is a preponderance of water-soluble aromatic compounds. 

The analysis of Prudhoe Bay Crude Oil for the hydrocarbon components under study is presented in Table V, together with the percentage of the total hydrocarbons found represented by each of the hydrocarbon types. For comparison, the contribution of component types to the total hydrocarbon is listed for both a filtered and unfiltered seawater suspension. The comparison is somewhat biased because benzene was not determined in the crude oil, being poorly separated from the hexane solvent, and because C4-benzenes were not determined in the unfiltered sample. However, it can be readily seen from the results that while aromatic hydrocarbon types are present in the crude oil in roughly equal concentrations, the preponderance of the total hydrocarbons in the seawater suspension is composed of the low-molecular-weight aromatic hydrocarbons. In both unfiltered and filtered systems, 90% of the water-soluble aromatic hydrocarbons found are composed of benzene, toluene, ethyl benzene, and the xylenes. This is in contrast to their concentration in the whole crude oil, which is at most a few percent and where their contributions to the hydrocarbons analyzed for is probably less than 30%. 

HPLC analysis of the aromatic subfraction of the water-soluble and the chloroform-extractable fractions of untreated bilge water produced the following average proportions hydroxylated aromatics, 50% aromatic hydrocarbons, 46% and heterocyclics, 4% (Figures 5 and 6). In the treated effluent, the aromatic subfraction was found to be hydox-ylated aromatics, 79% aromatic hydrocarbons, 15% and heterocyclics, 5% (Figure 7). 

Produced water is an extremely complex chemical solution, comprised of liquid water, minerals dissolved from formation rocks, and water soluble organics from the hydrocarbon phase. The most important inorganic compounds with corrosion implications are chlorides and buffering compounds (bicarbonate, borate, silicate, etc.). The presence of buffering compounds reduces corrosion by raising the solution pH, compensating for the effect of dissolved acid gases. An accurate, detailed analysis of the... 

GC is not generally used for COR analyses because most IPC samples are nonvolatile and potentially thermally labile in nature. " There are some exceptions however Muller et al. used GC to determine in-process COR reaction of a poorly water-soluble volatile aromatic hydrocarbon with a polymer. GC analysis was also used to monitor reaction progress and follow the formation of a process impurity (vinyl nitrile) by Vaidyanathan et al. ... 

The heavy metal salts, ia contrast to the alkah metal salts, have lower melting points and are more soluble ia organic solvents, eg, methylene chloride, chloroform, tetrahydrofiiran, and benzene. They are slightly soluble ia water, alcohol, ahphatic hydrocarbons, and ethyl ether (18). Their thermal decompositions have been extensively studied by dta and tga (thermal gravimetric analysis) methods. They decompose to the metal sulfides and gaseous products, which are primarily carbonyl sulfide and carbon disulfide ia varying ratios. In some cases, the dialkyl xanthate forms. Solvent extraction studies of a large number of elements as their xanthate salts have been reported (19). 

Tsonopoulos, C. (2001) Thermodynamic analysis of the mutual solubilities of hydrocarbons and water. Fluid Phase Equil. 186, 185-206. 

Wasik SP, Brown RL (1973) Determination of hydrocarbon solubility in seawater and the analysis of hydrocarbons in water-extracts. In Proceedings of the conference on prevention and control of oil spills. American Petroleum Institute, Washington, DC, pp 223-237... 

---