>946 ' ~ 2,408,752 uuirso stares PATENT} orricev . PREPARATION or BRANCHED CHAIN . HYDROCABBONS . Robert E. Burk, Cleveland Heights, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, ' N0 Drawing. Application April. 18, 1942, . Serial No. 439,543 2 Claims. lCl. 260-45835) In the common procedure of catalytic isomeri- ' plehydrogen bromide, hydrogen chloride, hydro zation, there is considerable side reaction of breaking up of molecules or cracking. This in- gen ?uoride; and these may be in liquid or gas eous state. Pressures up to 200 pounds‘ per terferes with the production of the ‘desir 'd kind square inch maybe applied in the reaction Zone of hydrocarbons, and also represents ‘a 'corre-v 5 with the halide in‘the gaseous state. vWhen the spending amount of waste of material." I have hydrogen halide is maintained as a-liquid suffi found that if isomerization be carried first to only eierlt Pressure is used to preserve the liquid a slightly branched condition and an isomer be ‘phase. An especially effective catalyst is a liquld iractioned out relatively clean from the reaction EFL-Eli's catalyst, the partial pressure of boron mixture, th'is clean out can be then isomerized 10 ?uoride being 50 to 550 pounds per square inch, quite . drastically without cracking.thus Di?erent equilibrium conditions are involved stage- preferably 150 pounds The operating temperatures in general desir wise, instead of in the customary run-through with a starting material, and the usual cracking ably are 10W,11nder 00° C. Preferably they may be below ordinary temperature and in the range loss may be obviated, and desired isomer prod- 15 011Where down todesired, minus 25 01' 30° C may be present, 1-10 uctsbe obtained. isobutane To the accomplishment of the foregoing and 111015, Preferably 2 01‘ 3 mole Hydrogen may de related the invention, then, comprises the ~ sir'ably also be Presentto be treated are , subjected featuresends, hereinaiter fully described, and particrl‘he hydrocarbons ularly pointed out in the claims, the following 20 to the aforedescribed conditions for a time de description setting forth‘ in detail certain illuspending on the temperature, the particular com trative embodiments of the invention, these being position of the catalyst, etc. to convert them to indicative however, of but a few of the various slightly branched hydrocarbons. Then, the hal ways in which the principle of the invention may are removed, such‘desiredway, as by freezing be employed. 25 ide out, catalysts or by distillation or other and As raw material, hydrocarbons which it is dethe hydrogen halide may be removed by releas sired to isomerize, in general may be applied. ins Pressure, neutralizing, 6110- Then the Prod The light hydrocarbons, as of live to eight carbon ‘lets are fractionated to Separate the Slightly atoms are especially applicable. Naphthas may _ branched hydrocarbons, and slleh thus in rela be thus treated. rI‘hese are desirably fraction- 30 tively pure form are then subjected to the afore ated mto cuts corresponding to hydrocarbons 0 described conditions to isomerize them into more a given number of carbon atoms which are then highly branched hydreeerben?- Where desired, isomerized separately. The hydrocarbons to be this product may be then fractionated, and a rela isomerized in the ?rst step or the operation may tively pure branched isomer may be again ‘fur be normal saturated hydrocarbons. Any con- 35 thel‘ ell-‘elected t0 the isemei‘izatien venient, source of hydrocarbons may be used how_ As an example: N-hexane is treated with 10 mol ever. In some cases it is desirable to start with slightly branched hydrocarbons. Where the hydrocarbon 00115 or raw material contain unsa — p91‘ cent of A1311 P1115 H131‘, the temperature be mg not higher than 0° . o and Preferably the Operation being Started at mlml 2 C Atter urated and aromatic hydrocarbons in addition to 40 about 130 hours, depending upon the precise tem paraf?n hydrocarbons, these may be removed, ‘for example by extracting with selective solvents or by reacting with halides for that purpose. petetlll'ee maintained, the product contains something over half isomers, 2-methyl pentane being largely predominant Ome neOheXane is ' As catalysts, the halide catalysts in general @150 formed The product is fractionated, and may be employed. Advantageous are the alumi- 45 the 2-methyl pentehe out is sublected to 10 mol num halide catalysts, such as aluminum chloride, per cent of aluminum bromide and hydrogen bro aluminum bromide, or complexes formed by these mide at about minus 11° C. for about 217 hours. halides with hydrocarbons, or alkyl halides may The product is mostly more highly isomerized be used; also other halides such as acid-acting hexanes, especially 3-methyl pentane, and small halides of zinc, iron, arsenic, antimony, tin, 5() er amount of 2,3-dimethyl butane. These may boron, etc. Mixtures of such catalysts are 'debe fractionated'out and again be separately sub sirable in some instances. The amount of cata- jected to the halide catalyst for further isomeriz lyst may be 1 to mol per tocent basedthe on halthe ation. hydrocarbon. It is10desirable promote As another example: 3-methyl pentane is treat ide catalyst by a hydrogen halide, as for exam- 55 ed at minus 11° C. with 10 mol per cent AlBI's ___.-— 2,408,752 As another example: 2,3—dimethyl ‘ butane treated as in the foregoing example yields a prOd- ‘ ~ orm more highly branched iso e process for converting normal to slightly not containing 76.4 per cent of isomeric hexanes, 10' branched hydrocarbons to highly branched iso 2 per cent being neohexane. No isobutane is formed, and only 0.1 per cent of isopentane. ther modes of applying the principle of the invention may be employed, change being made mers by a unitary two-stage process, which com prises subjecting hydrocarbons having 5 ‘to 8 car bon atoms~closely fractionated to contain pri marily normal to slightly branched para?inic hy aS regards the details described, provided the 15 drocarbons of the same number of carbon e equivalent of such be employ d catalyst promoted by hydrogen halide at a tem therefore particularly point out and distinctperature below ordinary temperature to form 1so~ y aim' as my invention: mers slightly more branched than said starting A process for convelting normal to slightly 20 hydrocarbons, separating the so-formed slightly branched hydrocarbons to highly branched iso branched isomers from the remaining hydrocar mers by a unitary two-stage process, which com bons and subJectmg said separated isomers to prises subJectmg hydrocarbons having 5 to 8 car furt er isomerization W1 h an alummum halide on atoms~closely fractionated to contain pncatalyst promoted by a hydrogen halide at a tern marily'normal tolslightly branched para?inic hy- 25 perat'ure below ordinary temperature to form drocarbons of the same number of carbon more highly branched isomers. atoms-t0 isomerization with a halide catalyst at ROBERT E. BURK.