Pure Hydrocarbons from Petroleum.

Abstract

HE naturally occurring Ca hydrocarbons in crude oil (with the exception of 2,2-dimethylbutane) were isolated by the National Bureau of Standards in A. P. I. Research Project 6 (2, 2A, 3, 7). Bruun, Hicks-Bruun, and Faulconer later isolated the missing isomer from a West Virginia natural gasoline of selected boiling range (4). The sample contained no naphthenes or aromatics, and was resolved by several successive distillations in 52-and 100-plate fractionating columns. This straightforward procedure was not possible for the naphtha from the crude oil, because of the methylcyclopentane, cyclohexane, and benzene present in the Ce fraction.A great deal of information was amassed on naturally occurring hydrocarbons, their physical properties, and their mixture behavior during the course of -4. P. I. Research Project 6. With that as a background, Rossini recently developed a systematic procedure for analyzing the straight-run gasoline fraction of petroleum and published preliminary results on East Texas and Oklahoma samples (IO). The method consists of separating the aromatics by adsorption on silica gel, then performing an "analytical distillation" upon the separated portions. While a single distillation upon each portion resolved them sufficiently for accurate analysis, the distillations must be carried out in a low-capacity column and under very high reflux ratio. The time required is from many hours to as long as several months. One of the purposes of this paper is to show that, by a further initial separation of the sample into essentially paraffinic and naphthenic portions, the analytical distillations are greatly expedited.Pure Ca hydrocarbons are not now being separated from petroleum in commercial quantity, although an immediate demand for them is anticipated as soon as they become T A quantitative analysis for the hydrocarbons present in a narrow-boiling mid-continent hexane fraction (from natural gas) was obtained by nitrating out the benzene, separating the aromatic-free mixture into essentially paraffinic and naphthenic portions, and then fractionating each portion in a Podbielniak Heli-Grid column. In contrast to reports on other straight-run hexane fractions, its 3-methylpentane content was too small for identification of this hydrocarbon.available a t reasonable price. Several commercial "hexanes" are on the market; in general, they are prepared by fractional distillation. These are promising source materials or concentrates for preparation of the pure hydrocarbons. MATERIAL AND FRACTIONATIONA quantity of Skellysolve B was obtained from the Skelly Oil Company who reported the source to be natural gas from the Burbank field of Oklahoma. Inspection tests showed:Distillation--Gravity, A. P. I. 74.9 Initial B. P. 148' F. d i 0 0.6814 5 % over 150 n %o 1.3840 10% 150 Aniline point, O C. 59.2 20% 151 Bromine No., mg./g. 0 . 7 30% 151.5 40% 1.52 50% 152.5 153 153.5 154 155 156 95% End point 165 Recovery 99.0% Residue 0 . 2 Loss 0 . 8 E P ET!As a preliminary analysis, samples of the material were carefully frac...

Determination of Total Beta-Carotene in Sweet Potatoes and Sweet Potato Products. An Improved Method

“…It must be recognized that petroleum ethers are actually mixtures of straight-chain, iso, and cyclic hydrocarbons and, although prepared under rigidly specified procedures, may vary greatly in performance as spectrophotometric solvents. Griswold and co-workers (7) have shown the impossibility of preparing a truly pure hydrocarbon from such mixtures.…”

“…Petroleum ether fractions cannot be used with satisfaction. Griswold and his co-workers (7) have shown the presence of a large number of compounds in the petroleum ether fractions commonly used, and the impossibility of obtaining pure straight-chain hydrocarbons by fractionation. Commercially pure hexane and heptane have been suggested as solvents in the analysis for carotene (22,30), but these are recognized as mixtures.…”

Dehydrogenation of Methylcyclopentane over Chromia-Alumina Catalysts

“…Dehydrogenation of cyclohexane over conventional dehydrogenation catalysts leads primarily to benzene and cannot be easily arrested at cyclohexene. It has been suggested to dehydrogenate methyleyclopentane (MCP), a hydrocarbon relatively abundant in naphthenic crude oils (3)(4)(5)(6) and isomerize methylcyclopentene to cyclohexene (7). Dehydrogenation steps described in the literature have been carried out over molybdena-alumina or chromia-alumina catalysts in the absence or presence of external hydrogen.…”