Hydroaromatic bases in the kerosene distillate of California petroleum
Creators: name: Armendt, Bradshaw Frederick
Publisher: name: The University of Texas at Austin
Year: 1932
Subjects: subject: California petroleum
subject: California kerosene
subject: Fractional distillation
subject: Crystallization
subject: Extraction
subject: Hydroaromatic bases
subject: Kerosene distillate
subject: C₁₆H₂₅N
subject: C₁₃H₂₁N
subject: Fractional precipitation
subject: Fractional crystallization
subject: Kerosene bases
subject: Petroleum--California
subject: Kerosene--California
subject: Distillation, Fractional
subject: Crystallization
subject: Extraction (Chemistry)

description: This paper deals in particular with the study of two hydroaromatic bases, one of the formula C₁₆H₂₅N, isolated and studied by Dr. W. C. Thompson, and the other of the formula C₁₃H₂₁N, discovered by the writer. The C₁₆H₂₅N base was isolated by Dr. Thompson by fractional precipitation as picrate from a 22% solution of the 276° fraction in 50% acetic acid. A hot concentrated solution of picric acid in 50% acetic acid acid was added in successive portions to the hot acetic acid solution of the bases. Between additions of picric acid the solution was allowed to cool and the picrates filtered off. The pure picrate was then obtained by exhaustive fractional crystallization and the base set free by means of ammonium hydroxide. The C₁₆H₂₅N compound is probably available in greater quantity than any other kerosene base. It represents about 20% of the 275° fraction and this fraction represents approximately one-twentieth of the total kerosene bases; hence it may be calculated that around 600,000 barrels of McKittrick petroleum would be required to produce one barrel of this particular base. The C₁₃H₂₁N base was isolated from fractions boiling between the range 215° to 226°. It was observed that a certain small fraction of bases which had been thru four fractional distillations having a boiling point of 220.8°, had an index of refraction at 30° of 1.4890, which was considerably lower than that of neighboring fractions. This low value suggested the possible presence of a hydroaromatic base in considerable quantity in this particular fraction. Accordingly, all available fractions of bases boiling between the range 215° to 226°, and possessing indices of refraction in the neighborhood of 1.4890, were subjected to five or six fractional distillations, with recombination in the order of boiling points and refractivities of the various fractions between successive distillations. Finally, four batches of bases were obtained with boiling point ranges 215.3-218°, 220-221.5°, 223-224.5°, and 225-226°. These four fractions were then each subjected to fractional acid extraction with normal sulfuric acid. In this way a subdivision into four approximately equal portions was effected and next fractional picrate precipitation was carried out by successive additions of a hot concentrated solution of picric acid in water or alcohol to the bases in the form of acid sulfates. The picrates formed in each step were separated and in this manner 32 fractions were obtained, all of which were taken thru exhaustive fractional crystallization from alcohol, with melting points and crystalline structure as a guide in subsequent recombinations. Approximately 50 g. of a pure picrate with a melting point of 158.7° was obtained finally, from which about 22 g. of the base was liberated by the action of concentrated ammonium hydroxide. The low refractive index of the latter product indicated a saturated hydroaromatic substance. From its analysis and a molecular weight determination was derived the empirical formula C₁₃H₂₁N. The amount of the various distillation fractions, in which it might be expected to occur totaled only 708 cc. and the small quantity obtained precludes at this time any very extensive work directed toward proof of structure. Therefore, it was decided to characterize the substance by the preparation of a few salts and compare its chemical behavior with that of the only other known hydroaromatic base from petroleum, a product of the formula, C₁₆H₂₅N, previously referred to