with absolute alcoholic potassium hydroxidc arid the resulting two isoiiicric cliloroethoxyquinoliiies were separated and their structures proved. 2. 2,4-Dichloroquinoli1ie, 2-chloro-ðoxyquinoline, I-chloro-S-ethoxyquinoline and 2chloro--4-liydro?ryquinolirle were condensed with various amines giving 5ex~eralnew amino- and
tliatiiitioquinoliiies. I-Chlorocarbostyril failed to react. ;;. 4-Amino-2-ethoxyquinoline failed t o react with compounds containing active halogen atoms, howel-er, two derivatives of this amine were prepared. JANUARY 20, 19-12 I~~~~~~~ s,xFBRASKARFCEIVED
[CONTRIBUTION FROM TIIE SCHOOL OF CHEMISTRY AND PHYSICS O F THL PENNSYLVANIA STATE COLLEGE]
Higher Hydrocarbons.’ I. Seven Alkyl Substituted Docosanes BY FRAKKC. WHITMORE. L. H. SUTHERLAND? AND J. N. COSBY While a large amount of exceIlent work has for a quantity of at least 100 g. Additional checks been done on the systematic study of the lower are given by molecular refraction values and failmolecular weight hydrocarbons, there is very little ure to show change in composition on solvent exaccurate information on hydrocarbons containing traction and treatment with silica gel.’ I n this paper seven simple isoparaffins from over twenty carbon atoms. Outstanding excepto CS:! have been prepared and studied. Four of tions are the investigations of Mikeska3and Recently another investigation of this type has these have a straight Czz chain with n-butyl groups been reported by Neyman-Pilat and Pilat:) ’Their on the fifth, seventh, ninth, and eleventh carbon work includes the properties of seven C2?hydro- atoms, respectively. The other three have the same CZ2chain, but with n-hexyl-, n-octyl-, and carbons, previously prepared by TurkiewiczS6 Approximately two hundred aromatic hydro- n-decyl groups on the seventh, ninth, and eleventh carbons in this range have been made by various carbon atoms, respectively. By this selection it workers for carcinogenic tests. Unfortunately was possible to vary widely the symmetry of the the study of the other properties has been very molecule. limited. For this reason their preparation is of Two general methods of synthesis have been only secondary interest to this work and will not used in the present work. 7-n-Butyl-, 9-n-butyl-, be considered in this paper. - . n-BuMgBr The compounds studied and the meth--+ R -CN R-C=o ods used in the present work have been carefully selected t o aroid complications due to rearrangement or other side reactions. Special emphasis has been placed I< -C R’ -+- olefini f- R-C---OH on the purification of the intermediates. 1 rju BU Every effort has been made to obtaisi a high standard oi purity in the finished hydrocarbons. and I 1-n-butyl-docosanes were made in the steps The purity of the products has been determined shown. 5-n-Butyl-, 7-n-hexyl-, 9-n-octyl-, and by means of time--temperature melting curves. 1I -n-decyldocosanes were made as follows Supplementary evidence has been obtained from Tz’ distillation-refractive index curves and distillaIZ COOMe + 2R’MgBr +R-&-OH tion-viscosity curves. A compound is accepted I only if those data indicate a purity of over 9.5GG H --f
I
(1) American Petroleum Institute Project No. 4 2 . Advisory I (1;) Turkivwic-7, % v , , 73,861 f I W 0 )
I
J R’
K‘
Table I is a summary of the important properties of these hydrocarbons. As the reason for I
(7) Mair and White, J . Rcsuarch .Va!l l~17sil Willingham. ihid , 2 2 321 fI%Vl)
B w . Slandardc, 16, 5 1
SEVEN ALKYLSUBSTITUTED DOCOSANES
June, 1942
1361
TABLE I THEPROPERTIES OF THE SEVEN ALKYLSUBSTITUTED DOCOSANES Docosane
11-n-Butyl9-n-Butyl7-n-Butyl5-n-Butyl7-n-Hexvl9-n-Octyl11-n-Decyl-
Empirical formula
C26& C26H54 C26H64 C26Hh4 CZEH~E Cso& C32H66
Melting point, OC.
Boiling point at 1.0 mm., OC.
nz0D
0.0 1.3 3.2 20.8 19.3 8.6 1.0
194 193 194 195 209 222 235
1.4500 1.4498 1.4499 1.4503 1.4517 I 4537 I 4543
d 204
0.8046 ,8041 ,8040 ,8057 ,8078 ,8112 ,8127
Molecular refraction Found Calcd.
122.2 122 3 122.3 122.1 131.5 140.8 150.0
122.3 122.3 122.3 122.3 131.5 140.7 150.0
Viscosity at 20° (centipoises)
15.35 15.65 16.48 17.15 18.55 22.25 25.88
the synthesis of the compounds was to obtain data useful in establishing the chemical composition of lubricating oils, a large number of other properties are being determined. This information will soon be published in the appropriate journals together with the related generalizations. With the exception of one hydrocarbon, 11-12decyldocosane, those given in this paper have not been reported before. The preparation of that compound by Klos, Neyman-Pilat and Pilat* came to our attention after the completion of our work. The properties of the two preparations agree well.
the bromides were distilled through an all glass column of 25-30 theoretical plates. (b) Methyl Esters.-The esters of lauric, myristic, and palmitic acids were prepared in large runs by the methanolysis of coconut oil and bayberry wax.ll These crude esters after washing with water and drying over calcium chloride were distilled through columns of 25-35 theoretical plates. The methyl oleate was prepared by refluxing 1080 g. of oleic acid (Eastman Kodak Co. technical), 1500 cc. of methanol, and 75 cc. of concentrated sulfuric acid for thirty-six hours. After washing and drying, the product was distilled with difficulty through a 25-plate column a t 5 mm. (c) Acids.-Lauric, myristic, and palmitic acids were prepared in almost quantitative yields from the saponification of the pure methyl esters. (d) Nitriles.-Following the procedure of Ralston, Experimental Intermediates.-The greatest of care has been used in Harwood and Pooli2 the lauro-, myristo- and palmitoobtaining pure intermediates. Fractional distillation nitriles were prepared in good yields by passing ammonia columnsg with 25-35 theoretical plates have been used in through the molten acids a t 290-300”. The nitriles were then distilled a t 10 to 30 mm. through a 25-plate column. all cases where distillation was possible. Where it was (e) Butyl Ketones.-5-Hexadecanone, 5-octadecanone, impossible to use these efficient columns a less efficient and 5-eicosanone were prepared by adding lauro-, myristocolumn or a Claisen flask was used together with repeated recrystallizations. The properties of the intermediates arc and palmito-nitriles, respectively, to a slight excess of nbutylniagnesiurn bromide in runs of 1.3 to 2.0 moles. The given in Table 11. Thc importance of great care in the purification of thc Grignard addition products were decomposed with excess intermediates cannot be overemphasized. Unless the dilute sulfuric acid and ice. After separation of the ether starting materials are free of isomers or closely similar im- layer and extraction of the water layer with 500 cc. of purities it is hopeless to try any purifications of the hydro- ether, the combined solutions were stripped of ether and carbons prepared from these intermediates. For this rea- the crude ketone distilled through a modified Ciaisen flask a t 1.0 to 3.0 mm. The best fractions were then recrystalson we give rather complete data on our intermediates. lized from ethyl acetate. (a) Bromides.-These were prepared from the tech1l-n-Butyldocosane~3.-A Grignard solution was prenically available alcohols. The alcohols were refluxed with the mixture of hydrobromic acid and sulfuric acid pared from 212 g. (0.96 mole) of decyl bromide in the formed in the reduction of bromine with sulfur dioxide.1° usual manner. To this was added 97 g. (0.43 mole) of 5-hexadecanone dissolved in 500 cc. of anhydrous ether. The ratios were usually 8 moles of alcohol to 15 moles of hydrobromic acid. Refluxing generally was continued After stirring overnight the mixture was hydrolyzed with for twenty-four to thirty-six hours. The alkyl bromides ice and a slight excess of sulfuric acid. After separation were then separated from the acid solutions by steam dis- and ether extraction, the ether was distilled off and the Mation. The products were washed with half their residue was fractionated under vacuum in a modified Claivolumes of cold 95% sulfuric acid, next with ammoniacal sen flask. The tertiary alcohol was dehydrated a t 175180” on anhydrous copper sulfate in an atmosphere of methanol-water solution and finally with water. After drying several days over anhydrous potassium carbonate, nitrogen. The resulting olefins were filtered through a short ( 8 ) Klos,Neyman-Pilat and Pilat, J . ApPlied Chem. (U. S. S.R.), column of silica gel to remove the copper sulfate and other
13, 1389 (1940). (!I) T o be described in a separate publication to be submitted to the Analytical Edition o f l n d u s i ~ i aand l Engineering Cheniiatry. (IO) “Organic Syntheses,” John Wiley and Sons, Inc., New York, h’. Y . .Coll. Vol. I, 1032, p. 23
( 1 1 ) An adaptation of the niethod of “Organic Syntheses,” Vol
xx,p. 07.
(12) Ralston, Harwood and Pool,THISJOURNAL, 59, 086 (1937) (13) See Table 1 .
P I L ~ NC. K \.T~HITMORL, L.H. SUTHERLAND AND J.
N. COSBY
Vol. ti4
TABLE I1 PROPERTIES OF
THE
INTERMEDIATES
Compounrl,
hlclting/~point,
n- B utyl bromide
S 5 -!KJ
u-Hexyl bromidc
--
n-Octyl hrornidc
(i5 -SI)
n-1)ecyl hroinide
711 -7.7
I ? )
O C .
100 99.5 155 156 111 201 124 118
85
1 . 155s
740 734 (M') 738 760 ( H ) 47 760 ( H i 30 13 (11)
llcthyl 1:sters 1 4320
Methyl lauratc
I i:$(i!J
19
18.8 (I') 29 29." (1;)
Fatty Acids
44,43.7 (F) 54,54.4(F) 63,62.9 (F)
Lauric acid hlyristic acid Palmitic acid Nitrilcs 1.auroni trilr
75--85
l(j0 198 168 169 173 251.5
blyristotiitrilc Palmit onitrile
30 100 ( R )
12 13 (R) 7 100 (R)
Rutyl 1;ctones 36-37 44-45 53-54
145 2 170 2 195 2 " The yields are calculated on the basis ol the pure intermediates. " The temperatures are not corrected. Sources of the literature values are indicated: ( W ) Whitmore, Karnatz, and Popkin, THIS JOURNAL, 60,2540 (1938) ; (H) Heilbron "Dictionary of Organic Compounds," Oxford University Press, New York, N. Y . , 1936; (F) Francis and Piper, THIS JOURNAL, 61, 577 (1939); (R) Ralston, Harwood, and Pool, ibid., 59,986 (1937). 5-n-Hexadecaiione
5-n-Octadecanoiic 5-rl-Eicosanonc
impuritics. This purification makes hydrogenation much S~dsiLi 'flit, alii!oat Nater-whitt olcfiua wcrc theu charged iiito a high pressure bomb." The hydrogenation was iiiore Lhan 95% coniplete in less Ihdn an hour at 1.80U It). per sq. in. and 170" over Li. 0. P. Shaking waa continued for five hours to ensure complete hydrogenation. The nickel was removed by filtration and the product distilled slowly a t 0.5 mm. through the high vacuum column!' (an efficiency of 4-5 theoretical plates). The fractions having constant refractive indices were passed through a column of silica gel to yield the water-white, odorless isoparaffin. Table I11 gives percentage yields and summary of analyses. 9-n-Butyldocosane and 7-n-Butyldocosane.-These were prepared in the same manner as 11-n-hutyldocosane. In the synthesis of each of these, runs of approximately 1 mole were macle, 114) Supplied by American Instrument Company, Silver Spring, Xld. ! 15) Sul>ylird bj- the i'viversd Oil Products Co., Chicago, Ill.
5-n-Buty1docosane.-A tertiary alcohol was prepared of 296 g. (2.0 iiioles) ol methyl oleate to the Grignard reagcnt prepared from ti85 g. (6.0 moles) ot u-hutyl bromide This tertiary alcohol was isolated and dehydrated in the same way as described for carbinol related to 11-n-butyldocosane. The resulting diolefins were found to be somewhat easier to hydrogenate and the overall yield was higher. 7-n-Hexyldocosane, 9-n-Octyldocosane and 11-n-Decyldocosam-The related tertiary alcohols were prepared by the addition of n-hexyl-, n-octyl-, and n-decylmagnesium bromides to the methyl esters of palmitic, myristic, and lauric acids, respectively. The alcohols were dehydrated and the olefins treated as before. I n each of these preparations a ratio of 5.0 moles of Grignard reagent to 2.0 moles of ester was used. Physical Properties.-Every effort has been made to obtain accurate physical properties to the extent justified by the pnrity of the compounds. The following is a list with I)y L ~ addition C
SEVEN ALKYLSUBSTITUTED DOCOSANES
June, 1942
1363
(e) Molecular Refraction.-The experimental values were obtained by use of the Lorenz and Lorentz equation.18 The calculated values are based on the Auwers and Eisenlohr atomic values.l8 (f) Specific Dispersion.-The values obtained from the drum readings of the refractometer by the use of tables to give values for ( n ~ - n c ) / da t 20" were about 91-93. It is generally recognized that values for the property obtained in this manner are not entirely reliable. Measurements by different observers will vary by as much as 4%. However, this order of accuracy is of value as there are much greater differences between isoparafih and aromatic or olefinic compounds. Plans are under way for more accurate measurements by the Bureau of Standards using TABLE I11 selected wave lengths of monochromatic light. F1'lIE YIBLUS, I'KJRITP AND A4NALYSESO F THE HYDROCARBONS (9) Viscosity.-The viscosity was measured a t 20.0° by Analyses,c % the use of a modified Ostwald viscosimeter.1g The instruSame, Moles" Yield,a Purity,b Found Calcd. C H docosane C H % mole % ' in run ments were calibrated against standard oils. These in turn 73 95-7 84.9 14.4 8 5 . 1 14.9 11-ii-Butyl0.43 are based on water as having a viscosity of 1.007 centi9-%-Butyl1.65 75 95-7 83.1 1 5 . 0 85.1 1 4 . 9 stokes a t 20 0". The values have an accuracy of 0.02 2.28 79 95-7 8 5 . 3 1 4 . 4 85.1 1 4 . 9 7-=-Butylcentipoise. 84.6 1 4 . 4 8 5 . 1 1 4 . 9 5-%-Butyl2.0 85 97 84.9 14.6 85.2 14.8 7-n-Hexyl2.0 78 97 Purity of the Hydrocarbons 80 95-6 85.6 14.4 85.2 1 4 . 8 9-n-Octyl2.0 Throughout this paper inferences have been made re11-n-Decyl0.95 75 95-6 85.1 1 4 . 5 85.2 14.7 lating to the methods of obtaining pure high molecular Yields and moles in runs are based on the amount of butyl ketone, or of ester used. The percentage given is the weight hydrocarbons. As this is the first of a series of yield of pure isoparaffin. The purity of the compounds papers it seems necessary to discuss the general problem was calculated from time-temperature melting curves of purity and the influences of impurities on the various (Ref. 16). With five of these seven compounds difficulties properties. To obtain pure hydrocarbons the intermediates must be in the interpretation of the data made it impossible to obtain exact values. ' Approximately twenty of these hydro- of the highest purity and side reactions must not give rise carbons now prepared by A.P.I. Project 42 were sent to a to isomers or other difficultly separable products. This is commercial analytical laboratory. The values reported necessary because of the limitations of purification methods by the laboratory indicated that there must be some diffi- that may be used in the high molecular weight range culty in the method of combustion or that our compounds The general methods that may be used are distillation, were less pure than we had good reason to believe. To crystallization, adsorption, and solvent extraction. Distillation of substances boiling in the range of 180check these results the Esso Laboratories through the 210" (1.0 mm.) is impossible in the conventional packed courtesy of Dr. L. A. Mikeska ran analyses on several of our compounds. Their checks with the calculated values columns because of the very high pressure drop. Therewere very good. The above analysis of the 9-n-butyl- fore complete separation by distillation through a column' such as has been used in this work cannot be obtained undocosane is a sample of their results. less there are differences in the boiling point of about 30". (b) Boiling Point.-The boiling point was taken from a However, the presence of impurities may be detected if vapor pressure curve for each compound determined over they differ by as much as 3' in boiling point. the range of 0.3 to 5.0 mm. These measurements were Crystallizationza has possibilities which may avoid the ' ~ was standardized using difficulty found with distillation. made in a special a ~ p a r a t u s that di-+butyl phthalate before and after. The vapor pressure .Idsorptioii on silica gel' has been used throughout this ineasurements were determined with a precision of 0.5 ', work and is of greatest value if its limitations are underThere was no detectable boiling range with the compounds stood. Separatiori occurs only when there are differences known to be pure (95% or better). in polarity. Moreover, the adsorptive capacity of the gel (c) Index of Refraction.-The refractive indices were is limited. Isomeric or homologous mixtures are not measured a t 20.0 * 0.01O using a Valentine "Universal" changed by its use. Abbe type refractometer. The instrument was checked As yet, general use has not been made of solvent extracagainst a series of pure hydrocarbons obtained from the tion. The results are similar to those obtained with silica Bureau of Standards. The results are correct to 0.0001 unit. gel. The method shows much promise and is being de(d) Density.-The densities were measured a t 20.0 i: veloped. Extraction studiesz1 on hydrocarbons not 0.01 using pycnometers holding about 5 ml. The values included in this paper showed very definite separation of are correct to 0.0002 g. per ml.
the methods of measurement of those important properties included in this paper. (a) Melting Point.-The melting point of the compound was taken as the "point of break" (solid to liquid) in the time-temperature melting curve. l6 The temperature is reproducible to 0.05" and was measured by a thermocouple standardized by comparison with thermometers checked by the Bureau of Standards. The accuracy of the standardization was 0.1". The range of melting is not included because it is impossible to determine exactly when the compound begins to melt. A study of the curves indicates that in all cases a t least 80% of the substance melted over a range of 1.5' or less.
'
O
(16) A paper giving complete details of this method has been submitted t o t h e Analytical Edilion of Industvial and Engineeying Chemistry. (17) Fenske, Chapter on "Laboratory and Small-Scale Distillation,'' The Science of Petroleum, Oxford University Press, London, 1938, Vol. 11, p. 1634.
(18) Gilman, "Organic Chemistry," John Wiley and Sons, New York, N. Y., 1938, Vol. 11, p. 1738 (19) Cannon and Fenske, I n d . Eng. Chem., Anal. Ed., 10, 297 (1938). 120) Private communication from Dr. F. D. Rossini a t the N a tional Bureau of Standards. (21) By Dr. K. A. Varteressian of this Laboratory.
1364
FRANK
c.
WHITMORE,
L. H. S U T H E R L A N D
impurities. However, systematic extractions equivalent to ten stages, using acetone as solvent, on a sample of the 7 11-hexyldocosane reported herein gave no indication of any sqnratiori. In spite of the limitatioiis involved in obtaining pure high molecular weight hydrocarbons, the problem has been solved to the extent of making coinpounds of bctter than 95 mole per cent. purity. First, all intermediates were prepared iii a high state ol purity (98.5 t o 99.3 mole per cent.). This eliminates all but a maximum of 3.0 inole per ccrit . OT isomeric arid honiologous inipurities in the finished pt'otiuc-1 traceable to impure starting material. Second, the rcactioiis used in the syii~ hcsis of the hydrocarbons were choscii t o minimize the possi1)le side reactions. Isolation of thr olefins, interinciliate in the syntheses involved a crude distillation, iii which impurities differing in boiling poiiit by 30° or inorr were eliminated. The more polar substances were t h e n at least partly removed by passage of the olefins through silica gel. The olefins ohtainetl a t this stage of the preparation were hydrogenated and the isoparaffiiis purified. Coni[)lr.tc hydrogenation was rather difficult and. in many cases as much as 2 per cent. of unchanged olefin remainrtl. Thr nickel and part of the olefinic and polar impurities were removed by passage through a tube of silica gel. This seep was followed by very careful fractiona! distillation to eliminate all of the impurities boiling as much as 30" from the hydrocarboii. This step also indicatcs the presence or absence of impurities differing by as much as 3" in boiling point. As a final step atid to remove any impurities arising from dccoinposit ion in distillation the constant refractive itidex fractions were passed through silica gel again to give the finished product. To determine the purity of this fitiishcd product is a problcin often as difficult as the preparation of the conipound. The only exact nicthocl is the use of time-tcinperature coolitig or mc~ltitigcurvcs. With the eompouiids studied only thc rriclt.ing curve has nuy valuc. This is 1)cvause of the difficulty iiitrotluced by t he uiiusual tfegrrc ol supcrcooling characteristic of these substaiices. A iiiethotl similar to that described by Mair, Glasgow a~itl RossiniL2was used. Certaiii rnodificationslG were iiecessary due to thc properties of our cornpouiids. 'Thc method is useless when glasses are formed and may not give exact values iri many cases if stereoisomers are present, or if there is a change in crystalline form in the process of melting. As a check on the purity of thc hydrocarbons, carboii and hydrogen analyses such as the ones reported in this paper are valueless. For this purpose it would be necessary t o havc an accnracy23 approaching atomic weight (22) &lair, Giasgow and Kossini, .I. Rcs. .V,>fl. Riri.. .ciotrriar.ds, $6, 391 (1941). ( 2 3 ) Iiossini, Proc. ..lvr. I'eluolcriiv I i i s l i l t c t e , 18 ( 1 1 1 ) , I 1 f1!4:37).
AND
J.
x. COSBY
Vol. 63
measurement,. However, the analyses do serve t o indicate that the compounds arc hydrocarbons and not oxygenated substances. There are additional checks on purities that may be of value. These are, in order of importance, the distillation curves, changes on passage through silica gel, the effect of solvent extraction, and properties such as molecular rcfraction. If one assumes that impurities are present to the extent of 5.0 mole pcr cent., the question arises as to what they may be and how they will influence the properties deterinined. Tlic present methods of purification will riot elimiiiatc isomeric impurities. They will eliminate homo1 ogous impurities only if thcre is a difference of at least three rarbon atoiiis. The finished product may pick 111) traces of iiioisturc and low boiling solvents from the air. T o avoid contamiiiatioii from the bottles used it is neces>ai-y to bake out the latter thoroughly. In terms of weight these arc iusignificarit, but in mole per cent. they may be very important. Thus 0.05% by weight of water beconws 1.0 mole per cent. The preseucc of 6 per cent. of isomeric impurities would influence only the melting point t o any extent. This may he illustrated by comparing the properties of the coinpounds in Table I. For example the presence of 5 mole per cent. of No. 1 in No. 1 would alter the boiling point of the latter a t 1 inm. by about 0.05', thg refractive index by 0.00002, the deusity by 0.00006 g./ml., the specific dispersion by an insignificant amount, and the viscosity a t 20' I-ry about 0.09 centipoisc.
Acknowledgment.-We thank our colleagues for their help : h'.C. Cook carried out the high pressure hydrogenations; G. H. Fleming and W. S. Sloatnian determined the purity of the coinpounds and their irteltiiig points; C. S . Rowland iiiatlc the tiieasurciiieiits on density atid viscosity, aiid K. r). Ilirikel did the boiling point rleterniinatiotis. Summsry 1. The preparatioti and five important erties are given for seven alkyl substituted sanes. 2 . Data on the yields and properties of seventeen intermediates are given. 3. The problem of the purity of such materials is discussed. SrATL
COLLEGLI, PBNNSYLVANIA RECEIVED DECEMBER 15, 1911
