Separation of petroleum hydrocarbons with silica gel

Abstract

The fractionation, by filtration through columns of silica gel, of a number of binary mixtures of pure hydrocarbons boiling from 80 to 175° C is reported.The results of these experiments show that (a) the aromatic and olefin hydrocarbons could be completely removed frum the paraffin and naphthene hydrocarbons, but the capacity of the gel as an adsorhent of the one olefin (" diamylene") investigated was only one-third of its capacity as an adsorbent of the aromatic hydrocarbons; (b) the capacity of silica gel as an adsorbent of the aromatic hydrocarbons was found to depend on the concentration of the solution and also, to some extent, on the components of the solution from which the aromatic hydrocarbon is being adsorbed, the amount of a-xylene, for example, adsorbed from a 10 percent solution of that aromatic in n-nonane being about 12 to 13 ml per 100 g of gel and approximately the same for gel of different grain size ; (c) a small but definite separ ation of naphthene from paraffin hydrocarbons occurred, the naphthenes tending to be adsorbed by the gel in preference to the paraffins; (d) a slight separation of normal paraffin hydrocarbons of d ifferent molecular weights occurred, the paraffin of low molecular weight being adsorbed in preference to that of high molecular weight; and (e) under conditions of these experiments, silica gel did not crack or otherwise attack aromatic, naphthene, or paraffin hydrocarbons.A simple laboratory method for the complete removal of aromatic from naphthene or paraffin hydrocarbons by adsorption on silica gel, with a recovery of 98 percent or better, is described. The method is very useful for invest igating the composition of petroleum distillates containing less than 15 percent of aromatic hydrocarbon. If

Comparison of the purity of samples of organic solvents by ultraviolet spectrophotometry

“…The number of filtrations required depends upon the type and amount of impurity, as well as upon the relative amounts of solvent and adsorbent. The effects produced by silica gel treatment [9] on the absorption curves of commercial n-heptane, cyclohexane, methylcyclohexane, 2,2,4-trimethylpentane, and decahydronaphthalene are shown in figures 1 to 3. n: w…”

“…Filtration of the solvent through various adsorbents is very effective for the removal of such impurities. Silica gel is a particularly efficient adsorbent that has been used extensively for removing aromatic and unsaturated compounds in the purification of petroleum hydrocarbons [9,10,11]. The number of filtrations required depends upon the type and amount of impurity, as well as upon the relative amounts of solvent and adsorbent.…”

Separation and recovery of aromatic hydrocarbons from paraffins and naphthenes by adsorption

“…Previous applications of this method to the separation of aromatic hydrocarbons involved principally hydrocarbons of high molecular weight and of biological importance. 4 While there are a number of reports on the use of the Tswett method in the field of petroleum chemistry [6,7,8,9,10,11], the method does not appear to have been used for the separation and r ecovery of aromatic hydrocarbons from naphthene and paraffin hydrocarbons.…”

Separation of the three methyloctanes from midcontinent petroleum

“…The presence of the methyl octane fraction in an Oldahoma petroleum 3 became apparent when, a few years ago, the material boiling normally between 140 and 145 0 C was redistilled after first removing the aromatic hydrocarbons by extraction [1]. 4 More recently, Tongberg, Fenske, and Nickels [2] have encountered the same fraction in petroleum from the Yates field in Texas.…”

“…To free the distillate from these constituents, all fractions boiling between 98 and 103.5° C were filtered through columns of silica gel. The procedure has been described elsewhere [3]. Briefly, fractions of distillate with narrow boiling ranges were filtered through glass columns, 3 by 50 cm, filled with gel of 40-to 200-mesh obtained from the Silica Gel Corporation, of Baltimore.…”