CHEMICAL RELATIONS BETWEEN WATER AND HYDROCARBONS. 107 
The naphthenic acids are the oxygen derivatives of the naphthenes 
(polymethylenes) and have tlie general formula C n H 2n _ 2 0 2 . These 
compounds were observed by Hell and Medinger 1 2 in 1874, and in 
1890 Aschan studied them in detail and gave them the name naph¬ 
thene carboxylic acids. The naphthenes are prominent constituents 
of much of the Russian, Galician, and Roumanian oil, and when such 
oil is exposed to the air, especially in sunlight, the acids tend to 
form. 3 These acids have been observed in waters associated with 
the Russian oil and have been studied by Kharitschoff, 4 who in recent 
years has published a number of papers on their properties and nature. 
Inasmuch as the naphthenes are, according to Mabery and Hudson, 5 
important constituents of the California and other American oils, it 
is probable that naphthenic acids are to be found in the water asso¬ 
ciated with these oils also. Fatty acids have been reported in oil-field 
waters by several of the earlier investigators, 6 but their identification 
has since been questioned. However, Thompson 7 has more recently 
reported fatty acids (probably oleic and palmitic acids) in the waters 
from wells in the Grosny district, Russia. Kharitschoff, 8 in waters 
from the same locality, reports carbonates of ammonia and the 
amines, and Schidkoff 9 reported in the oil itself small quantities of 
formic and oxalic acids. Hydroxyl derivatives of the nature of 
phenols have been reported in California and other oils, 10 and these 
compounds may also be present in the oil-field waters. However, 
the naphthenic and perhaps the fatty acids, which may be grouped 
under the general term petroleum acids, are probably the commonest 
petroleum derivatives in oil-field waters. In alkaline waters these 
acids are doubtless present as alkali salts rather than as free acids. 
So far as the writer knows, no attempt has been made to study or 
' even to determine quantitatively the petroleum acids in California 
oil-field waters, although, as already stated, several chemists have 
detected them qualitatively. It has been suggested that the presence 
1 Hell, C., and Medinger, E., Ueber das Vorkommen und die Zusammensetzung von Sauren im Roh- 
petroleum: Deutsche chem. Gesell. Ber., Band 7, pp. 1216-1223, 1874; Ueber die Oxydation der im 
Rohpetroleum enthaltenden Saure, C 11 H 20 O 2 : Idem, Band 10, pp. 451-456, 1877. 
2 Aschan, O., Ueber die in dem Erdol aus Baku vorkommenden Sauren von niedrigerem Kohlenstoff- 
gehalt: Deutsche chem. Gesell. Ber., Band 23, pp. 867-875, 1890; Band 24, pp. 2710-2724, 1891; Band 25, 
pp. 3661-3670, 1892. 
3 Ostrejko, R. A., Influence of sunlight and air on petroleum products (abstract): Soc. Chem. Ind. 
Jour., pp. 26, 345, and 645, 1896. 
4 Kharitschoff’s papers appeared mostly in Russian journals, but adequate summaries of them are 
given in the Chemical Abstracts and in the Journal of the Chemical Society of London. 
& Mabery, C. F., and Hudson, E. J., On the composition of California petroleum: Am. Acad. Arts and 
Sci. Proc., vol. 36, pp. 255-283, 1901. 
6 Potilitzin, A., Zusammensetzung des die Erdol begleitenden und aus Schlammvulkanen ausstromenden 
Wassers (abstract): Deutsche chem. Gesell. Ber., Band 16, p. 1395-a, 1883. 
i Thompson, A. B., Oil fields of Russia, p. 93, London, 1908. 
s Kharitschofi, K. V., Ueber die Analyse des Wassers aus den Bohrlochem des Grosnyschen Bezirkes: 
Chem. Centralbl., vol. 78, p. 295, 1907. 
» Schidkoff, N., Acid content of Grosny petroleum and derivatives (abstract): Soc. Chem. Ind. Jour., 
vol. 18, p. 360, 1899. 
Mabery, C. F., The composition of American petroleum: Am. Chem. Soc. Jour., vol. 28, p. 426,1906. 
