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Separation and Identification of the Major C7 to C10 Components Of U. S. Department of Commerce Research Paper RP1999 National Bureau of Standards Volume 42, June 1949 Part of the Journal of Research of the National Bureau of Standards Separation and Identification of the Major C 7 to CIO Components of Triptene Residue By Philip Pomerantz, Thomas W. Mears, and Frank 1. Howard As a part of an investigation conducted under the auspices of the National Advisory Committee for Aeronautics, the Bureau of Aeronautics of the Department of the Navy, and t he Department of the Air Force, embracing the synthesis and isolation of highly branched hydrocarbons, a series of systematic distillations was carried out on "triptene residue," a synthetic alkyl ate made at the Radford Laboratories of the General Motors Corporation. This report describes the isolation thereby of two heptenes, four octenes, and three nonenes; the identification of fonr heptenes, two octenes, three nonenes, and six decenes not ~ I resolvable by fractional distillation; and the isolation of two heptanes, two octanes, one nonane, and five decanes formed by hydrogenation of mixtures of olefins. Physical const-ants for the isolated products and graphs showing the course of the several distillation are pre­ sented. The analysis presented is based, where individual olefins were isolated, on the distillation' curves; where the mixtures obtained by distillation were more complex, the analysis is based on ozonolysis data and/or distillation data of the hydrogenated product. The mechanism of successive methylation by which the several olefins in the mixtu.re were derived has been shown to be valid. 1. Introduction As shown by Miller and Lovell, the process consists essentially of reacting methyl chloride The work described herein is part of an inves­ with the dehydration products of tertiary amyl tigation conducted for the National Advisory alcohol, in the presence of a specially prepared Committee for Aeronautics, the Bureau of Aero­ lime, to yield hydrocarbons of higher molecular nautics of the Department of the Navy, and the weight. Department of the Air Force on the synthesis The olefin reactant consist primarily of 2- and purification of highly branched hydrocarbons methyl-2-butene and lesser amounts of 2-methyl­ for the determination of their physical properties I-butene and 3-methyl-I-butene. Under the and for a study of their antiknock characteristics. proper conditions, the olefins are methylated at This report describes the isolation and physical the double bond to yield a more complex mixture properties of a number of hydrocarbons obtained of hexenes. The first step in the methylation is from triptene residue by systematic fractionation believed to proceed as illustrated below.2 and the identification of several others not isolated. Triptene residue is a byproduct of the manufac­ C C C * I CH3 CI I I ture of 2,3,3-trimethyl-I-butene (triptene). The C-C=C-C lime C-C=C-C details of the process and the mechanism of the chemical Teactions involved have been presented c C [22]1 by Verle A. Miller and W. G. Lovell. I * CH3 CI I C-C-C=C- I-Ime· - C-C-C=C-C ! Figures in brackets indi cate the literature references at the end of this paper. , Asterisks indicat.e point of methylation. Triptene Residue 617 The hexenes can react further to yield heptenes, Figure 1 3 shows the postulated course of the the most important of these being triptene. This methylations of the methylbutenes and the olefins methylation step is shown below. isolated and/or identified in this work. The compound 2,3,3-trimethyl-l-butene (trip­ C C C C I I CR3 C! I I tene) is the component of the methylation products c-C=c-c ----+ c-c- c = C( triptene) that is of the greatest interest, the methylation * lime I C reaction being used primarily to produce this c c c olefin. Besides having a high knock-rating, trip­ I * CR3 C! I I tene is the precursor, by hydrogenation, of 2,2,3- c-c-c=c-c ----+ c-c-c=c-c lime trimethylbutane (triptane), a compound having exceptional engine behavior. Large amounts of Successive, stepwise methylations of portions of the heptenes yield octenes, nonenes, decenes, and • This figure was adapted from the one published by Miller and Lovell [22]. This altered chart is reproduced by permission of the Editor of Industrial higher boiling materials. and Engineering Chemistry. c c ,.. C c-c=c-c ,.. C=C-C-C C-C-C=C " 1 c c cc C C C-C=G-C c-e-e=c c-c=c-c-c C-C-CII -C-C ! 1 1 1 c C I cg~c l C-C-C-C-C IDENTIFIED I SO L ATED I DENTIF lED 1 ""'\' ~""" '''"f'' , cc cc c-c (I) cc c cc I 011 II c-c-c=c·c c-c-c-c=c-c c=c-c-c-c c-c-c-c-c c·c·c·c·c '"z .J C C '">­ I SOLATED ISOLA TED IDENTIFIED ~ I SOLATED I SOLATED IDENTIFIED "o (I) ... 1 1 1 \ \ c o z ccc ccc ccc c cc cc cc o c-c-c-c=c ~ c-c-c-c=c ¢ c-c-e-e-c c-e-c-c=c-c c-c=c-c-c-c c-c-e-c-c ~ N" c c c IDENTIFIED C c a: '"~ I DENTI FI ED I SOLATED I SOLATED ISOLATED IDENTIFIED o \ \ \ c CC c ccc c c ccc ccc cc-c I " C-C-C-C=C-C C-C-e-c,c-c C-C-e-C-C=OC c-c-c-c-c c-e=c-c, -c-c c-c-c-c-c c c c C c C IDENTIFIED IDENTIFIED IDENTIFIED c" IDENTIFIED IDENTIFIED PARAFFIN ISOLATED F IGURE 1. Olefins isolated or identified in triptene residue. Principle products are enclosed by rectangles. 618 Journal of Research triptene were made by methylation at the Redford were needed in large quantities for engine tests and Laboratories of the General Motors Corporation, for synthetic work, and this alkylate appeared to separated from the reaction mixture by distilla­ be the most promising source of these compounds. tion, and then hydrogenated to triptane. The Accordingly, by arrangement with General Motors "bottoms" from this distillation is designated as Corporation, work was started on the fractionation triptene residue. of triptene residue in order to identify the major The identity of the components of triptene constituents of the alkylate through the decene residue aroused considerable interest at the Red­ range, and to isolate any hydrocarbons that could ford Laboratories, beca.use the verification of the be obtained by fractional distillation. presence of certain structures as formulated in figure 1 would throw light on the mode of methyla­ II. Equipment and Methods tion. The work that had been done on this prob­ 1. Distillation Equipment lem at the Redford Laboratories had been per­ formed on the hydrogenated heptene and octene There were seven stills available for this study; portions. More conclusive evidence, in the form these are listed in table 1. A more complete of the identification of olefins, was needed, par­ description of these stills is given in a previous ticularly in the nonene and decene range. report [14]. Still 9, having an efficiency of about In addition, interest was directed in this labora­ 40 theoretical plates at total reflex, was used for tory to the composition of triptene residue because the fractionation of the oily layer arising from the several highly branched members shown in figure 1 ozonization of fractions of triptene residue. TABLE 1. Distillation columns Number Still Material of con­ of theo· num· 'rype Size Packing retical Operat· Pot ca· ber struction plates ing reflux pacity (approx.) ------- - - In. Liter3/hr. Gal. Total reflux variable take- 16 by ~ ___________ Glass _______ _______ %.-in_ stainless steel helices m ade from 40 0. 1 ofL O.oo6-in. wire. 11 ___. Ao_. ___________________ 240 by 2 __ . ________ MoneL .. _________ ?i,-in. stainless steel helices made from 65 4to L __ 15 O.OlO-in. wire. 12 __ ___ do _____ ________ ________ 600 by 4 _____ ___ ___ Galvanized steeL.. ~s- in . unglazed porcelain raschig rings ____ _ 100 45 to 50 __ 55 13 _____ do______________ __ ____ _ 600 by 4 ____ . ________ ___do ________________ _Ao ___ . _______________ __ ______________ __ 100 45 to 50 __ 55 14 _____ do ____________________ _ 600 by 2 ___________ Stainless steeL. ___ H.-in. stainless steel helices made from 200 4 to 6_•• • 65 O.OlO-in. wire. 17 Podbelniak HyperraL __ __ 72 by L ______ . __ __ Glass ____________ __ H eli-Grid_. _______ __ __________ __ ___ __ ____ _ 100 2 to 3 ____ 22 Total reflux variable take- 72 by L __ . __________ __ _do _._. ______ ___ ~l .·in . glass h eli~es __ ___ ___• ____ __ ________ _ 35 2 to 3 ____ otT. Stills 11 to 14, inclusive, are of the total conden­ type; it was used for exploratory distillations of sation partial-takeoff type and were constructed material as received from the General Motors for analysis of commercial crudes, purification Corporation. of large amounts of materials, and for isolation of 2 . Fractionations hydrocarbons from commercial mixtures. Stills 12, 13, and 14 were used to process the bulk of the The material available for the present study was triptene residue, whereas still 11 was used for a 980-gallon shipment from the Redford Labora­ redistillation of several cuts and for the isolation of tories, which consisted of triptene residue, as paraffins from several of the hydrogenated cuts.
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