Separation of hydrocarbons by azeotropic distillation

Abstract

The following topics are discussed: the principles involved in azeotropic distillation; the substances that form azeotropic mixtures with hydrocarbons; the separation of hydrocarbons by azeotropic distillation, including aromatics from naphthenes and paraffins, naphthenes from paraffins, aromatic hydrocarbons having different numbers and kinds of rings, naphthene hydrocarbons having different numbers of naphthene rings, olefin hydrocarbons, and isomeric hydrocarbons; the differences in the change of boiling point with pressure for the difl"erent types of hydrocarbons; and the benefits of distillation at reduced pressure prior to azeotropic distillation at the normal operating pressure. A general procedure is outlined for separating a given (gasoline or kerosene) fraction of petroleum by means of distillation alone in its several variations (at the normal distilling pressure, at reduced pressure, and with an azeotrope-forming substance).

Heats of isomerization of the nine heptanes

“…The additional purification consisted in azeotropic distillation with methyl alcohol [10] through a column having a separating efficiency equivalent to about 140 theoretical plates [6], with subsequent filtration through silica gel [9]. The purified materials contained the following amounts of impurity, as determined by A. R.…”

Carbonization

“…The principles of azeotropic distillation have been discussed by Mair et al [43]; extractive distillation is the subject of several US and British patents [44]; and solvent extraction is exemplified by the Udex process [45], which employs mixtures of various polyethylene glycols in water.…”

Isolation of 1,2,3,4-tetramethylbenzene, 5,6,7,8-tetrahydronaphthalene, 1-methyl-5,6,7,8-tetrahydronaphthalene, and 2-methyl-5,6,7,8-tetrahydronaphthalene from petroleum

“…Since a detailed description of the procedures used in this laboratory for the separation of hydrocarbons by azeotropic distillation has recently been published [3], only a brief description will be given here. All the azeotropic distillations discussed here were performed at 217 mm Hg pressure with diethylene glycol monomethyl ether as the azeotrope-forming substance, in columns having a separating efficiency equivalent to about 100 theoretical plates.…”

“…There is also indicated by the value 0.083° C the difference -in temperature of thermodynamic , The distillation of such a small quantity of material in a large column was feasible only by the u~e of an azeotrope-forming substance which greatly increased the volume of distillate. (See reference [3]). The properties of the best samples, both the synthetic ones and those from petroleum, together with values from previous investigations, are given in tables 2 to 5.…”