July 11, 1913] 



SCIENCE 



41 



rotation than the kerosene was first ob- 

 served by Rakusin.^^ The naphthenie acids 

 derived from lubricating oils were found 

 by Marcusson^' to be much more strongly 

 active than those derived from kerosene. 



A study of isomeric naphthenie acids^* 

 has recently been made in the laboratory 

 of industrial research of the University of 

 Kansas. Commercial naphthenie acids, 

 after being freed from hydrocarbons, were 

 converted into esters, which were repeatedly 

 fractionally distilled. The lowest boiling 

 fractions were strongly Isevorotatory. The 

 succeeding fractions showed a gradual de- 

 crease until in the intermediate fractions a 

 neutral or inactive point was reached. 

 Above this there was a gradual increase in 

 dextrorotatory activity. A portion of free 

 naphthenie acids, which were similarly puri- 

 fied, were separately fractionated and gave 

 results exactly parallel to those of their 

 esters, the only difference being that the 

 boiling points of the free acids were uni- 

 formly about 50° higher than the boiling 

 points of their methyl esters. In other 

 words each and every optically active con- 

 stituent boiled 50° higher in the one case 

 than in the other. This shows that these 

 optically active constituents are acids which 

 are esterifiable, and marks the first distinct 

 step toward their isolation. The simplest 

 interpretation of these facts is that the 

 cause of the optical activity resides within 

 the naphthenie acids themselves. 



It does not necessarily follow, however, 

 that the optically active constituents pres- 



'^"Die Untersuchung des Erdols imd seiner Pro- 

 dukte," p. 178, 1906. 



^Chemiker-Zeitung, No. 33, p. 421, 1907. 



" Orig. Com. Eighth Intemat. Cong. Appl. 

 Chem., VI., 57-67, 1912. The same isomeric 

 naphthenie acids have since been independently 

 isolated, by the method of repeated fractional 

 crystallization of their amides, by Gadaskin and 

 Zaverschinsky, Jr. Buss. Phys.-Chem. Soc, 45: 

 377, 1913. 



ent in the commercial naphthenie acids 

 are identical with those originally present 

 in the petroleum. There seems to be good 

 evidence that this is not the ease, for it has 

 been show-n by Albreeht" that the optical 

 activity of lubricating oils is not appre- 

 ciably reduced by thorough refining by 

 means of alkali. This result has also been 

 confirmed by experiments with the Kansas 

 oil distillates already mentioned, which re- 

 tained most of their optical activity after 

 being boiled with alcoholic potash. On the 

 other hand, these experiments do not prove 

 that no optically active acids are removed 

 by the treatment with alkali, for it is quite 

 possible that both lasvorotatory and dex- 

 trorotatory acids may be removed in ap- 

 proximately equal quantities. To satisfac- 

 torily settle this question an experiment 

 should be carried out at a refinery upon a 

 large quantity of oil. 



The naphthenie acids are generally be- 

 lieved to be the oxidation products of the 

 naphthenes, or saturated cyclic hydrocar- 

 bons of the series C„H,„, which are present 

 in most of the petroleums, but particularly 

 in those of Eussia. It is to be expected, 

 therefore, that active acids should result 

 from the oxidation of certain active hydro- 

 carbons. The determination of the consti- 

 tution of any of the active acids to be found 

 in petroleum products would thus shed 

 light upon the constitution of the active 

 hydrocarbons from which they were 

 formed. 



The crucial test as to the correctness of 

 our knowledge of the constitution and 

 structure of organic compounds depends 

 upon the methods for their synthesis. But 

 chemical synthesis is a species of architec- 

 ture, and just as the architect before be- 

 ginning the erection of his structure must 



'^^ Chemische Sevue, 18: 189, 1911. See also 

 ' ' Die Polarimetrie der Erdole, " M. A. Eakusin, 

 p. 39. 



