T H E JOrRLV.4L O F I N D U S T R I A L A N D ENGIh'EERING C H E M I S T R Y
578
"STANOLITE" COEFFICIENT OF EXPANSION PER O F . 60-212' F. 0.000364 60-264" F. 0.000378
SPECIFIC GRAVITY 60/60° F. 1 ,0957 77/77' F. 1 ,0887
77-212' F. 77-264O F.
0.000337 0.000343
B y Weiss' method of calculation' t h e coefficient of expansion for t h e range 60-77' F. on t h i s sample is 0.0004I 2 . A sample of Mexican residuum having a specific g r a v i t y of 1.0104 a t 7 7 / 7 7 ' F. gave t h e coefficient 0.00032 for t h e range 77-160" F. CHEMICAL
1,ABORATORY
O F A I O R R I S 82
COMPANY
CHICAGO
RELATIONS AMONG THE PHYSICAL CONSTANTS OF THE PETROLEUM DISTILLATES By WALTERF. RITTMANA N D G U S T A VECLOFF Received J a n u a r y 4, 1915
I n t h e industrial s t u d y of petroleum a n d petroleum products s t r i c t l y chemical methods of identification a r e of secondary importance. T h e n u m b e r of reactions in use is limited, a n d these processes a r e n o t particularly convenient a n d satisfactory. T h e y fail t o give t h e s o r t of information most needed. F o r instance, t h e sulfonation t e s t for olefines gives t h e s a m e results whether t h e hydrocarbons h a v e a boiling point of 100' or 300°, a n d indicates little r e g a r d ing t h e commercial use or possibilities of a n oil. Likewise a liquid sulfur dioxide extraction does not a i d in differentiating a gasoline f r o m a kerosene. T h e i m p o r t a n t information i n t h e s t u d y of petroleum distillates is o b t a i n e d f r o m d e t e r m i n a t i o n s of
5'01. 7 , No. 7
t h e limits of experimental error no m a t t e r what device is employed t o secure t h e m . Viscosity coefficients for crude oils a n d refined produ c t s a r e commonly determined. M a n y chemists measure refractive indices, t h o u g h t h e use of t h i s r a l u a b l e method of identification is r a t h e r limited. Other physical c o n s t a n t s such as surface tension, capillary rise a n d molecular weight have been determined in only a limited n u m b e r of cases a n d their practical applications h a v e n o t been given extensive consideration b y petroleum technologists. F o r t h e purpose of determining possible simple relationships, measurements were made of t h e following series of c o n s t a n t s : A-Distillation range E--Surface tension B-Specific g r a v i t y F-Capillary constant C-Refractive index G-Molecular weight D-Viscosit y H-ULtimate analysis SAMPLES AXD D E T E R M I N A T I O N S
As t h e present work deals with a comparsion of constants, r a t h e r t h a n oils, i t was n o t considered necessary t o secure a n absolutely comprehensive series of samples. R e p r e s e n t a t i v e oils f r o m a n u m ber of different fields were obtained, a n d t h e select i o n was made with t h e view of including crude petroleums of different t y p e s . T h e list includes five carefully selected samples of California crude oils, five f r o m Oklahoma, four from Pennsylvania, t w o f r o m Russia a n d one f r o m Mexico. F r o m t h e works of M a b e r y a n d other investigators, it is known t h a t wide differences exist a m o n g t h e t y p e s of hydrocarbons f o u n d in oils from t h e different
T A B L EI-SOURCES A N D P H Y S I C A L C O N S T A N TOF S C R U D EOIL S A M P L E S LEASE WELL No. PHYSICAL CONSTANT OF S C R U D EP E T R O L E I I M S FIELDDISTRICT SAMPLED LOCATION STATEC O U N T Y A R R A N G E IDN O R D E ROF THEIR 15 269 Cal. Piru 12/ 6/07 T 3 N , R l 8 W Cal. Ventura Union Oil Co. SPECIFIC G R A V I T I E S 12/ 4/07 T 4 N , R18W Cal. Ventura Modella, 7, 19.21, 22, 28, 29 273 Cal. Piru
No.
587 Cal. 591 Cal. Heald 764 P a . I 765 P a . I 815 P a . 816 Pa. 1280 Okla. 1281 Okla. 13.36 Okla. 1339 Okla.
1
Midway Midwav
J. S. Sloan Farm Branden Farm Collinsville Collinsville Collinsville Collinsville
IO/ 8/10 T31S. R 2 2 E Cal. lO/l8/10 T31S. R 2 2 E Cal. 9/7/11 { 9/7/11
{
S. Maria R . R. Russian-Provided R. M. Russian-Provided M e x . Mexican-Provided
9/21/11 9/21/11 May/l3 May/l3 5/24/13 5/24/13
Emlenton Emlenton Pleasantville Pleasantville TZZN, R 1 5 E T22N, RISE T14N. R I S E T14N. R18E
Kern Kern
Manchuria, Midway Bear Creek
I 0
;
Pa. Venango Boulder S a n d : 1195 f t . Pa. Venango Second S a n d : 1050 f t . Pa. First S a n d : 580 f t . II Pa. Second S a n d : 650 i t . ' 6 Okla. Claremore Pool .. Okla. Sellers Lease, Claremore Pool 1 Okla. G. Callahan Lease, Muskogee Pool 3 Okla. Stevens cease, Muskogee Pool 1
by the kindness of C. I. Robinson of the S t a n d a r d Oil C o . of K.J. b y t h e kindness of Prof. C. F. M a b e r y T h e Case School Cleveland, 0 . b y the kindness of D r . D. T. D a y , U. 8. Bureau of Mine's. Washington, D. C.
v a r i o u s physical constants. I n view of t h e convenience with which t h e y can be measured, a n d t h e wide utility of these constants, it h a s been t h o u g h t desirable t o s t u d y relations existing a m o n g t h e m . T h e work described in t h i s communication deals with a comprehensive series of measurements a n d furnishes d a t a which are helpful in indicating how t h e results of various experiments m a y be interpreted. T h e t w o processes most universally employed a n d best understood are distillation a n d measurement of specific g r a v i t y . Distillation figures a r e more or less relative, depending u p o n t h e m e t h o d used.3 G r a v i t y measurements are absolute a n d agree within 1 John Morris Weiss, " T h e Coefficient of Expansion of Tar," J Frank Inst., Sept., 1911. 2 Published with the permission of the Director of the B u r e a u of Mines See R i t t m a n and Dean, THISJ O U R N A L7, (1915), 185
Sample 815 764 816 765 1336 1339 1280 Heald 1281 269 R. R . R . M. 273 s. M.
Sp. Gr. 0.799 0.800 0.808 0.816 n, 825 0.838 0.846 0,865 0.870 0.876 0.876 0.878 0.891 0.901
Viscosities Spec. Sec. I .30 67.5 67 1.29 I .32 68.5 1.40 73 I .44 7.5 1.71 89 1.70 88.5 2 . 7 7 I44 3.35 I i 4 2 31 I20 2 . 6 1 136 3.22 167.5 2.11 I I O 4 . 9 2 256
Surf. Cap. Tens. Conet. 24.0i 6. I7 25.12 6 . 4 4 24.81 6 . 3 0 25.44 6 . 3 8 24.78 6 . I S 26. 19 6 . 4 0 25.03 6 . 0 6 26.59 6 . 3 0 26.59 6.26 2 s . i n 6.no 27 55 6 . 4 3 27.82 6 . 4 9 76.08 5.99 26. I3 5 . 9 4
fields. Table I gives t h e sources a n d physical cons t a n t s of t h e oils studied. VISCOSITIES of t h e crude oils were measured in t h e S t a n d a r d Engler Viscosimeter at a t e m p e r a t u r e of 20' C. Results a r e expressed in Engler degrees, which represent ratios of t h e r a t e s of flow of t h e oil a n d water. When expressed in this m a n n e r t h e results indicate specific viscosity. T h i s is in c o n t r a s t t o empirical refinery practice using t h e Saybolt machine, which shows t h e t i m e required for a given q u a n t i t y of oil to pass a given orifice a n d omits comparison with t h e s t a n d a r d liquid, water. T h e conversion factors f r o m Engler' t o Redwood a n d Saybolt a r e :
+ 4 + e4) KZ
TR = I ~ Z . Z K ( I 1
I
Chem. R e s . Fell-Hare. Ind.. 19 (30, ,331, (44 to 49).
579
T H E J O L ' R S d L O F IAq-DL7STRI.4L i l S D E X G I A 7 E E R I X G C H E M I S T R I -
July, 1 9 1 j
a cut is selected. it will be noted t h a t densities of Pennsylvania products are least and those of California and Russian greatest. This is in accord with 0.0701 3 observations of other investigators and is a striking K = o.08019E E evidence of the difference among t h e hydrocarbons T h e values calculated from t h e formulas agree with contained in petroleums from different fields. Pennthose actually observed within 4 per cent b y Red- syll-ania oils contain paraffins which have :I OW wood a n d z per cent b y Saybolt. By dividing the gravity for a giren boiling point: California and RUSreadings for Redwood a n d Saybolt instruments by sian oils contain cyclic compounds which are heavier the respective readings for water! comparative accuracy for the same boiling point: Oklahoma oils, containfor these instruments is increased. ing both types of hydrocarbons, give intermediRttDISTILLATIOXS were conducted according t o a method gravity values. which was designed t o give a high degree of separaR E F R A C T I V E I S ~ I C E S were measured by means of :I tion. I n accordance with t h e results of some recent Pulfrich Refractometer. Determinations were m a d e investigations conducted under the direction of one a t room temperature, maintained a t 20' C. of t h e authors.' a Hempel column of definite height T h e use of refractive index as a means of identiwas provisionally adopted as standard for this set of experiments. The degree of efficiency attained was fication of oils is t o be recommended. T h e method approximately t h a t of the standard creosote flask? is simple, 1-apid, and only a few drops of liquid are Comparatively little of the Forestry Division of t h e Department of Agri- necessary for a determination. has been done in the use of refractive index b y culture. T h e flasks here used were of t h e following petroleum technologists, despite its wide utility in dimensions : identifying essential oils. T h e property is an addi400 cc. Height f r o m bulb t o outlet 6 in. Initial charge Capacity of bulb 500 cc. Height from outlet t o top 1 ' , $ in. ti\-e one and within certain limits we can assign t o 5 , in. ~ Cuts at 50' inter\.& 100 to 300' C. Diameter of neck of bulb each a t o m in t h e molecule a certain share in the reFractionating column: 5 in. aluminum beads (between I , I and 3,'g in.) T h e results of distillation, shown in Table 11, need fractive index of t h e molecule. T h e above property is emphasized by t h e present no discussion in t h e present connection. T h e Kern River and hIesican Oils were emulsified and frothed experiments. T h e values increase in the ascending badly, and t o overcome this difficulty it was necessary order with increase of specific gravity of a series of t o apply heat t o t h e neck of the flask, which obviously oils: this is clearly shown when t h e oil is graphed against specific gravity and refractive index. altered t h e effect of t h e fractionating column. TABLE Source Cal. Sample 269 Temp. To loOD 8 . 0 0 100-150° 1 0 . 5 0 150-200° 8.25 200-250: 11.00 2.50-300 11.25 '1'0 100; 100-150
150-200" 20@-25O0 250-300°
T o 100' 100-150" 15O-20O0
200-2J0" 25O-30Oo To 100" 100-1500
150b200° 200-250° 250-300'
150--200° ?0&25O0 ?50-300°
11-RESULTS OF FRACTIONAL DISTILLATIONS OF PETROLEUM OILS A N D CONSTANTS OF VARIOUS DISTILLATIOK CUTS Cal. Cal. Cal. Cal. Pa. Pa. Pa. Pa. Okla. Okla. Okla. Okla. Okla. Russian 273 58; 591 S. M. 764 765 815 816 1280 1281 1336 1339 Heald R. R. R. M. VOLUME-PERCENTAGES 5.25 0.38 ,. , 6.75 5.19 6.25 6.25 8.25 3.25 0.31 8.38 5.50 5.00 0.62 1.12 15.50 0.50 ,., 13.25 7 . 3 8 13.75 6 . 6 3 14.25 1 4 . 2 5 3 . 3 8 12.50 12.25 8.62 11.13 7.38 10.25 1.50 1.25 8.62 6.06 1 1 . 5 0 6 . 0 0 1 2 . 7 5 1 0 . 3 8 10.75 11.12 9.50 7.38 11.50 8.62 12.63 5.25 5 . 2 5 11.12 6.12 11.50 5 . 2 5 11.75 13.88 1 4 . 1 2 11.12 11.75 10.25 13.75 12.75 1 2 . 0 0 1 6 . 0 0 1 0 . 6 3 15.00 6.19 12.50 57.5 1 1 . 7 5 1 4 . 8 8 16 7 5 12.63 15.00 17.00 15.25 15.62 SPECIFIC GRAVITIES 0 688 0.706 . . ,,, 0 , 7 0 6 0 . 6 8 6 0.682 0 . 6 7 1 0 . 6 8 6 0 . 7 0 5 0.680 0.689 0.690 0.733 0,756 0.762 0 . 7 6 2 0 . 7 3 6 0 . 7 4 8 0 , 7 3 7 0 , 7 4 0 0 746 0:iSi 0 . 7 4 9 0 . 7 5 2 0,754 0:767 0.769 0 792 0.805 0 : b i O 0:626 0 . 8 0 6 0 . 7 6 6 0 . 7 8 0 0.767 0.7il 0 , 7 8 1 0 . 7 8 5 0 . 7 8 3 0 . 7 8 5 0.791 0.804 0.806 (1 825 0 . 8 5 1 0 . 8 5 8 0 . 8 6 0 0 . 8 4 6 0 . 7 8 9 0 . 7 9 9 0 . 7 9 2 0 , 7 9 3 0 . 8 1 4 0.815 0 . 8 0 9 0 . 8 1 2 0.818 0.836 0.836 0 855 (1.891 0 . 8 8 7 0 . 8 9 0 0 . 8 7 8 0 . 8 1 2 0.818 0.815 0 . 8 1 3 0.839 0 . 8 3 9 0 . 8 3 1 0 . 8 3 6 0.839 0.861 0.861 INDICES OF REFRACTION 1.386 1 . 3 9 0 1 . 4 2 3 . . 1.392 1.385 1.385 1 . 3 7 5 1 . 3 8 6 1 . 3 8 9 1.409 1 . 3 8 5 1.387 1.388 1.401 1.403 1.418 1.419 1 . 4 3 4 1 420 1.407 1.416 1.408 1 . 4 1 0 1 . 4 1 3 1 . 4 1 9 1 . 4 1 6 I 417 1.418 1.421 1.423 1.436 1 . 4 4 0 1.445 1:348 1.444 1.425 1 . 4 3 0 1.426 1.427 1 . 4 3 1 1 435 1 . 4 3 2 1 . 4 3 4 1.435 1.439 1.441 1 . 4 5 5 1 . 4 6 5 1.465 1.465 1 . 4 6 5 1.437 1 . 4 4 3 1.438 1 . 4 3 9 1.449 1 . 4 5 0 1 . 4 4 8 1 . 4 4 8 1.451 1.457 1.45; 1.472 1 . 4 9 3 1 . 4 8 4 1 . 4 8 4 1 . 4 8 3 1 449 1 . 4 5 2 1.449 1.449 1 . 4 6 4 1 . 4 6 4 1 439 1.461 1 465 I 472 I 474 SURFACE TENSIOXS 19.54 18.92 ... 2 0 . 7 8 18.81 18.87 19.11 1 9 . 5 3 1 9 . 9 9 19.85 1 8 . 9 2 19.71 . . ? I . 19 22.12 2 2 . 3 3 . 2 2 . 4 7 20.95 21.87 21.67 2 0 . 9 8 22.05 2 2 . b 9 2 2 . 0 9 2 1 . 5 3 22.34 72.75 22.80 2 2 . 7 0 24.55 2 5 : 2 5 2 5 . 3 6 2 5 . 3 1 23.29 2 4 . 0 0 23.75 2 2 . 6 4 24.25 2 4 . 3 5 2 4 . 0 7 22.91 23.98 24.8.5 14 9 3 24.9') 26.50 26.71 2 3 . 4 7 2 6 . 4 3 2 8 . 6 2 2:.22 2 6 . 2 8 2 5 . 0 4 2 5 . 2 9 2 5 . 4 2 2 3 . 6 7 2 6 . 1 3 2 6 . 1 2 25.61 23.91 2 3 . 8 1 28.18 2 9 . 5 1 2 8 . 0 3 28.04 2 6 . 4 7 2 6 . 8 4 2 6 . 8 0 2 4 . 4 8 2 7 . 4 8 2 7 . 3 7 27.02 2 4 . 4 5 26.01 27.15 28.01 CAPILLARY COSSTAXTS OR SPECIFIC COHESIONS 5.64 5.69 5.86 5.84 5 .50 6.04 5,84 5.82 6.00 5.64 5.86 .5 93 6.0(1 6.01 6.07 . . . 6.06 5.84 6.13 6.03 5 , 8 1 6.06 6 . 1 5 6.05 5.88 6.08 f, 08 k i n 6 . 2 9 6.44 6 . 2 3 6.46 6 . 3 5 6 . 0 2 6 . 3 2 6.36 6.31 5.99 6 25 5.87 6 21 6 34 6.34 6.36 5.82 6.36 6.83 6.51 6.61 6.58 6.48 6.12 6.57 6.56 6.49 6 03 6.26 6 49 6.5 5 6.81 6.68 6.79 6.73 5.71 h 47 6.45 6.54 6 66 6.16 6.71 6.68 6 46 5 99 6.44 6.67 CRYOSCOPIC S ~ O L Z C U LWEIGHTS AR 133.3 12,; 8 1 3 1 . 4 142.9 125.9 1 3 7 . 6 121.7 139.8 1 3 0 . 3 1 3 2 . 2 138 3 130 6 130 7 I27 8 I27 6 119.1 166.7 1 5 2 . 7 1 5 1 . 5 179.2 140.0 164 5 1 5 9 . 4 1 6 7 . 3 14Y.0 1 5 8 . 4 170.1 165 9 153.9 159.8 146.4 140.; 1 9 1 . 6 1 7 3 . 2 181.8 1 9 3 . 9 179.6 2 0 2 . 6 184.2 2 0 5 . 8 1 8 0 . 9 195.7 212 3 7 1 4 . 3 1 9 0 . 6 192 5 171.3 180.5
SPECIFIC'
GRAVITY
determinations were
made at
1 5 ' C. by the use of a special small K e s t p h a l Balance
with a plummet of I cc. displacement. iz s t u d y of t h e specific gravities shown in Table I1 brings out one fact, which, though well known. is worthy of comment. If for a n y given temperature Lac. cit. Dean and Batemail, Bidl. 112, Forest Service of the C. S . Department of Agriculture. 1
2
.\leaic;tn
1.12 2.50 8.25 25.75 O.fj9
0.i98 0.843 0.871 I 419 1.439 1.464 1.481 , ,
,
.
24.62 26.36 27.26
6.33 0.30 h 41 142.7 178.3 197.7
S U R F A C E T E K S I O S - U ~ t o the time of beginning this rcsearch b u t little attention has been given t o the tietermination of surface tension and capillary constants of petroleum and its products. This phenomenon is important t o the geologist' as well as t o the chemist. Surface tension is a direct result of unbalanced inter-molecular forces a t the boundary between t h e liquid and gas phase, and is manifested by the apparent !
Hull. A n i . I n s f M i n . Eng,. 1914, p. 2365.
T H E J O I ' R S . 1 L O F I,\iDlvSTRI.4L
580
A.VD ELVGINEERING C H E M I S T R Y
v01. 7 , XO. 7
formation of a n elastic skin. T h e familiar experiC A P I L L A R Y C O N S T A K T O R S P E C I F I C coHEsIos-The ment of floating a greasy steel needle o n water is t h e capillary constant is a derived function of surface tensimplest a n d most impressive way of demonstrating sion a n d specific gravity. It h a s been largely used t h e existence of a tension along t h e surface of a liquid. in t h e past a n d many values in t h e literature are Two common resulting effects are t h e tendency of expressed i n t e r m s of this constant. For purposes all liquids t o form spherical drops whenever possible of comparison t h e surface tension values obtained b y a n d t h e rise in t u b e s of all liquids which are able t o t h e d r o p weight method have been c o n v x t e d i n t o wet t h e material of which t h e t u b e is composed. Surface tension measurements x e r e made by t h e use of t h e Morgan1 drop weight a p p a r a t u s . The method evolved b y Morgan2 a n d his co-workers is simple, rapid a n d highly accurate. I t has in addition t h e a d v a n t a g e of being particularly a d a p t e d t o liquids which a r e mixtures of several constituents of different volatilities-whereas. t h e capillary rise method fails u t t e r l y under these conditions. T h e method gives directly a n d accurately t h e weight of t h e drop of t h e liquid. F r o m this t h e value of surface tension can be calculated b y t h e following relation:3 y = Surface Tension (dynes per cm.) = KIT 'where K = T h e constant for t h e a p p a r a t u s used a n d W = Weight of a drop in milligrams. It will be noted from t h e results shown in Table I1 t h a t surface tension is apparently a n additive prope r t y a s f a r as t h e distillation cuts of a n y one oil are concerned, b u t t h a t a d d i t i v i t y vanishes when t h e relations of different petroleums are considered. An explanation is not difficult t o find, for it has been demons t r a t e d b y Morgan4 t h a t small additions of certain substances influence greatly t h e surface tension of a solvent. T h u s in t h e presence of I per cent of a m y l alcohol t h e surface tension of water decreases 48 per cent! while I per cent of phenol: in water produces a 1 7 per cent depression of surface tension. All this indicates t h e possible occurrence in crude petroleum of small quantities of substances which have a large influence o n surface tension a n d which are distributed throughout t h e various cuts of a distillation. On this basis it is easy t o understand why t h e a p p a r e n t additive n a t u r e of this constant vanishes when relations of different original oils are considered. W i t h pure hydrocarbons, of homologous series, surface tension is a n additive property. T h a t phenols, cresols, mercaptans a n d other sulfur a n d oxygen compounds exist in crude petroleums has been clearly shown by t h e work of Markownikoff a n d 'Ogloblin,6 Pebal a n d F r e u n d , ' Ha11.8 T h i e l ~ , ~ a n d Mabery.'O T h e above mentioned observations on surface t e n sion have indicated interesting possibilities for research. It is hoped t h a t in t h e near f u t u r e investigations along these lines m a y be conducted a n d knowledge of more specific character obtained. RELATIONS A M O N G PHYSICAL CONSTANTS OB PETROLEUM DISTILLATES 1
3 4 6
6 7 6
* 10
J . A m . Chem. Soc., 32 (1911), 349. 2 . physik. Chem., 1916; Jour. A m . Chem. Soc.. 1911-1915 (rPsurnC-). J . A m . Chem. Soc., 33 (19111, 658. Ibid.. 96 (19131, 1860. Results on phenol not published-Morgan and Egloff Bcr., 16 (1883). 1873; Chem. Z l g . , 1881, p . 609. Liebig's A n n . , 115 (18601, 19. J . Soc. Chem. I n d . , 1907, p. 1223. Chem. Zlg., 17s (1901). 433. Proc. A m Acad.. 36 (1901). 2 5 5 ; 40 (1904), 318
capillary constants. Transformations were made by t h e use of t h e following formula:' a2 =
2Y
9.8d
y = Surface Tension d = Specific Gravity
a * = Capillary C o n s t a n t 1
Morgan, "Principles of Physical Chemistry," 1914, p. 100.
Values of ti for 10' TTere calculated (see Table 11) from those measured a t I j " b y conrersion figures gi\-en by SI arkownikoii-Ogloblin* for Xmerican oils. a n d b y lIendelejeff2 for Russian. CRYOSCOPIC " ~ I O L E C L - L A R KEIGIIT "---The a\-erage "molecular weights" of t h e jo" c u t s betn-een I j o o a n d 300' were determined by t h e cryoscopic method, using benzol as a solT-ent. S o measurements w r e " of t h e made o n fractions boiling below ~ j o because possible presence of benzol in these distillates. T h e concentration of solute \vas kept practically constant a n d t o eliminate possible \-ariatiom due t o association so as t o make all determinations comparahie. T h e ~ - a l u e sof solute were between 0 . 1 2 t o 0 . I j of a g m . ; ~vliereast h e solvent neighed from 13 t o 18 gms. T h e temperature readings 75-ere made with a Reichsanstalt certified Beckmann thermometer. T h e solvent used 17-as Kahlbaum's thiophen-lree, recrystnllized benzol. T h e benzol was further purified b y 'r.4BI.E
I~-PHYhIC.41,
C O S S T A X T S OF
765 i64 0.682 0.686 1.385 1.385 18.87 1 8 8 1 5.69 5.64
Cap.const...
815 1336 0.670 0.680 1.375 1.385 19.11 19.85 5.86 6.00
SA~IPLE S p gr , . 1iei.ind . . . . . S u r , t e n. . . , C a p . con% .
764 815 816 0.736 0.93; 0.740 1.407 1.408 1.410 21.95 21.67 20.98 5.84 6.03 5.81
.
Sur. t e n
SAMPLE S p g r... . . . . K e f . ind. . . .
.
,
.
Sur t e n . . , . . . , Cap. const.. . . . XOI. w . . . . , . ,
764 815 816 0.76i 0.771 0.766 1.425 1.426 1.427 23.29 23.75 22.64 6.23 6.35 6.02 138 140 1.30
SAMPLE 764 815 816 S p , g r . . . , . . . . . . 0.789 0.792 0.793 Rei. i n d . . . . . . . . 1.437 1.438 1.439 S u r . t e n . . . . . . . . 25.04 25.42 23.67 C a p , c o n s t. . . . . 6.51 6.58 6.12 Mol. w t , . I . . 165 167 149 SAMPLE i64 816 815 Sp. g r . . . . . . , . . 0.812 0.813 0.815 Ref. ind . . . . . . 1.449 1.449 1.449 S u r . t e n . . . . , . . . 26.47 24.48 26.80 6.16 Cap. const . . 6.68 6.13 xt0i. \Yt , . . . , 203 181 206
B t i . , 16, 18i3. Rakusin, C n i e r s u ~ l i .d . Erduls. :' J . .4m.C h r m .Sot., 36 11914), 1825. :
a n d indicate for a number of Xmerican oils, practicallypure hydrocarbons Tvith small a m o u n t s of osygen.. nitrogen or sulfur compounds, whereas one Russian a n d t h e l l e s i c a n oil show a relati\-ely high per cent of oxygen, nitrogen or sulfur compounds, which might bear o u t t h e s t a t e m e n t as t o small a m o u n t s of certain extraneous substances greatly changing t h e surface tensions of pure hydrocarbons. T h e relations existing among t h e \.arious sets UP TO
IS O R D E R O F S P E C I F I C G K A V I T I E Y
100' C .
816 269 133'1 Heald 1280 1281 273 0.686 0.688 0.689 0.690 0.705 .. 0.706 1.386 1.386 1.38; 1.388 1.398 .. 1.390 19.53 19.54 18.92 19.71 19.99 .. 18.92 5.84 5.84 5.64 5.86 5.82 .. 5.50 F n A c T r o N B P. B E T W E E X looo A S D l j o 3 1280 765 1336 1330 Heald 2'69 1281 Mex. 0.746 0.748 0.749 O.i5? 0.754 0 756 0 7 5 7 0.759 1.1413 1.416 1.416 1.416 1.418 1.418 1.419 1.419 22.05 21.87 2 2 0 9 2 1 5 3 22.34 22.12 22.69 .. 6.06 6 I? 6.05 5.88 6.07 6.00 6 15 . F n A c T 1 o . v B. P. B&T\VEEX 15oo .4ND 200" 76.5 1280 1336 1281 1.339 Heald 269 h3ex 0.785 0.791 0.792 0.798 0.781 0.783 0 . 7 8 5 0.i80 1.431 1.432 1.434 1.434 1.435 1.436 1.439 1.430 22.91 2 3 9 8 2 2 . 7 0 24.62 24.00 2 4 2 5 24.07 14.3.5 6.33 6.32 5.99 6.21 5.87 6.31 6.36 6.46 143 128 133 132 131 122 131 138 F n A c r r o X B. P. B E T W E E N 200' A N D 2 5 0 " i65 1336 1339 1280 1281 Heald 269 R. R. 0.799 0.800 0.812 0.814 0.815 0.818 0.825 0.836 1.443 1.448 1.448 1.449 1.450 1.451 1.455 1.457 25.29 25.61 23.91 26.13 26.12 24.00 2 3 . 4 7 26.50 6.61 6.49 6.03 6.57 6.56 6.26 582 6.49 159 166 154 158 170 160 167 146 FRACTION B. P. B E T W E E N 2.50' A X D 300' i65 1336 1339 1280 1281 Heald 269 R. R 0.831 0.836 0.839 0.813 0.839 0 . 8 5 5 0.861 0.818 1.459 1.461 1.464 1.464 1.465 1.472 1.472 1.452 27.02 24.45 27.48 27.37 26.01 23.81 27.15 26.84 6.66 6.68 6.34 5.71 6.46 6.19 5.99 6.71 212 184 214 191 19.3 192 171 196
t h e method advocated b y Richards3 a n d Shipley for freezing point in thermometry. Every experimental precaution v a s t a k e n to eliminate errors due t o impurity of solvent, weighing vessels a n d thermometer. T h e average "molecular weights" as determined are given in Table 11. I t appeared from these experiments t h a t " molecular weights" did not exhibit a n agreement with t h e valucs for specific gravity a n d refractive indes. S e i t h e r was there a n y agreement between '' molecular weights" a n d surface tension or capillary constant. I t also appeared t h a t molecular weights" were lower t h a n would be indicated from calculations concerning hydrocarbons boiling between t h e given temperature limits. This discrepancy is probably d u e t o t h e fact t h a t t h e actual average boiling tem"
I I I - ~ ~ L T I x ~ TAXALYSES c OF CERTAIX200-250' B 1'. PK.\CTIOSS Sample S o . 269 1281 816 Kern S. 31. I l e x . R. 11 X . K . Per cent hydrogen 13.62 1 3 . 9 0 14.57 1 3 . 4 0 13.07 1 3 . 3 4 13 42 l i . 3 i Per cent c a r b o n , , . 8 6 . 3 6 8 5 . 3 ; 84.99 8 6 . 2 7 85.42 85 .OO 86 34 81.45'
TAnLB
DISTILI.ATION CUTS
FR~CTIO B.NP. SAMPLE Sp. gr . . . . Ref. i n d . . . .
perature of a cut obtained o n distilling a crude oil is lower t h a n t h e nrerage indicated by t h e given limits. 1-I. TI I[ .iT E .isI\ L T s I s--- E i g h t samples of di still a t e s of b . p . 2oo-rjo0 ITere analyzed for t h e carbon a n d hydrogen content. T h e results appear in Table I11
S. SI.
0.706 1.392
20.78 6.04
R. R .
. 1.401
.. ..
R 11, O.iS3
587
0804 1.439
24.85 6.34 128
273 0.805 1.440
14.55 6.25 126
Slex.
Kern
il~i'
21.1~2 5.93
273 S. h l . K . K. R . X I . 0.762 0.762 0 . i 6 i 0.i69 1.419 1.420 1.421 1.42.1 22.31 2 2 4 7 2 2 . 7 5 22.80 6 01 6.06 6.08 6.08 R . R.
,591
1.423
1.40s
1.434
..
R. 11
S. X Kern ,iOI 0.806 0806 0 . 8 2 0 0.826 1.441 1.444 1.445 1.448 2 4 . 9 3 25.31 25.25 2 5 . S 6 6.,34 6.44 6.30 6.29 II'J 126 131 141
R. M. 1 I e x . S. M. ?ii Kern jYi 0.836 0.843 0.846 0.851 0.858 0.860 1.457 1.464 1.465 1.465 1.465 1.465 26.71 26.36 26.28 26.43 28.62 27.22 6.55 6.39 6.36 6.36 6.83 6.48 141 178 140 152 151 179
R . 11. Mex. S. >I. K e r n .~ 591 7 .7 1 0.861 0.871 0.878 0.887 0.890 0 . 8 Y l 1.474 1.481 1.483 1.484 1.484 1.403 28.01 27.26 28.04 29.51 28.03 28.18 6.69 6.41 6.54 6.81 6.45 6.47 181 198 180 173 182 194 ~
~
~
of constants are shown b y t w o comparison tables. Table I\' represents cuts boiling u p t o 100'. from IOO~ j o " from , I~O-200'. from 2 0 * 2 j o o , a n d from 2 j o 300'. T a b l e T' represents d a t a on combined cuts u p t o I jo", generally classed b y petroleum technologists as " n a p h t h a , " a n d combined c u t s from 1503 0 0 ' . generally classed as kerosene." Comparisons are best made b y t h e use of the accompanying graphs plotted f r o m t h e values for t h e last three series in Table I V . These are representative of t h e results of all t h e other tables a n d were selected because t h e y include t h e most comprehensive lists of constants. The graphs are plotted using as abscissas e q u i distant points, each representing a different oil. T h e oils a r e arranged in such order as t o give a n ascending curve for specific gravities. An inspection of t h e graphs s h o w t h a t t h e only constant bearing any clcarcut relation t o specific gravity is refractiT-c indes.
T H E J O I * K S . I L O F I L V D C S T R I A L A.VD E-VGIiVEERING C H E M I S T R Y
j82
T h e curve f o r surface tension is decidedly irregular b u t shows a tendency t o slope upwards. This indicates t h a t among petroleum hydrocarbons surface tension varies in t h e same direction as specific gravity. This constant is, however, so strongly affected by small variations i n chemical composition t h a t it is a t present of little value as a means of identification. I t is hoped, however, t h a t later these irregularities may be understood well enough t o furnish scientific as well as, useful industrial information. Capillary constant curves show t h e same irregularities as those of surface tension b u t lack t h e slope upward. This is to be expected when t h e method of derivation of t h i s constant is considered. I n considering t h e molecular-weight ” graph, i t appears t h a t t h e agreement of this constant with C O N S T A N T S OF “ N A P H T H A ” A N D “KEROSENE“ CUTS OF Or1.S STUDIED UP TO 150° C. KEROSENE-B. P. 150’ T o 300’
V---Cryoscopic ‘ I molecular weights,” as measured b y t h e cryoscopic method with benzene as a solvent. are of questionable value in t h e s t u d y of mixtures of petroleum products. T h e experimental work connected with t h e determinations reported in this paper was carried o u t in t h e laboratories of t h e Departments of Physical Chemistry a n d Industrial Chemistry of Columbia L‘niversity, New York. CHEMICAL SECTION OF PETROLfiUM DIVISION L,. BUREAU O F MINES, PITTSBURGH
s.
THE SPECIFICATION OF VULCANIZED RUBBER GUM BY VOLUME AND ITS DETERMINATION BY A NEW SOLUTION METHOD By FRANK GoTTscH Received April 21, 1915
T A B L E \‘-PHYSICAL
NAPHTHA-B. P. Sample Sp. Refr. Surf. Cap. No. gr. index tens. const. 815 764 816 13.16
765 269
0 706 0.716 0.722 0 726 0.731 0.733
1.392 1.398 1 400 1.402 1.405 1.406
19.96 20.54 20.02 20.52 19.34 21.12
5 82 5.88 5.69 5.79 5.57 5.97
Heald 0 . 7 3 4 1 . 4 0 6 2 0 . 3 8 5 . 6 9 1339
0 , 7 3 6 1.407 1 9 . 4 1 5 . 4 1
1280 S. M . 273 R . hi.
0.741 0,744 0.750 0.765
1.410 1.410 1.412 1.418
20.28 21.34 20.74 22.37
5.61 5.87 5.6i 5.99
Sample Sp. No gr. 815 76 4 816 765 13.36 1281 1339 1280 269
Heald R. R . R . M.
273 S. M.
Mex. Kern 59 I
0.789 0.790 0.292 0.195 0.808 0.811 0.814 0.815 0.820 0.824 0.836 0.841 0.842 0.849 0.861 0,878 0.878
Refr. Surf. Cap. index tens. const 1 ,437 1.438 1.439 1 ,440 1 ,445 1.448 1 ,449 1.451 1.452 1.454 1.458 1.459 1.463 1.466 1.475 1,476 1.476
24 73 25.07 23.96 24,66 2 5 . 59 26.80 23.91 25.04 23.18 25.27 26.34 26.57 25.50 26.40 26.96 27.79 26.87
6.44 6.50 6.20 6.43 6.49 6.66 6.02 6.30 5.77 6.28 6.45 6.46 6.20 6.37 6.40 6.48 6.26
specific gravity, though theoretically t o be expected, is conspicuous b y its absence. N o satisfactory explanation appears except t h a t there is some inherent error i n t h e method here employed for t h e determination of molecular weights. Present experience indicates t h a t t h e measurement of this constant b y t h e cryoscopic method with benzol as a solvent is of doubtful value i n t h e identification of petroleum distillates. T h e experimental values are recorded with a full knowledge of their being (‘so-called A\Iolecular Weights.” COXCLUSIONS
I-The present series of experiments has tended t o , justify t h e methods of identification (distillation, specific gravity a n d refractive index) usually employed in petroleum testing laboratories. 11-Volatility a n d specific gravity are t h e t w o most important constants a n d a knowledge of these two is generally sufficient for t h e identification of a n oil. 111-Refractive indices v a r y in t h e same direction as specific gravities. When only small quantities of distillates a r e available, determinations of t h e former are more convenient t h a n measurements of specific gravities. IV-Surface tension is a constant not yet of value. T h i s is o n account of o u r lack of knowledge regarding variations caused b y t h e probable presence of small quantities of certain substances in crude petroleums. Surface tensions in general seem t o increase with specific g r a v i t y when relations among petroleum hydrocarbons a r e considered.
YO]. 7 , NO. 7
T h e following methods for t h e chemical analysis of rubber goads are those in use at M t . Prospect Laboratory, D e p a r t m e n t of Tf7ater Supply, Gas a n d Electricity, C i t y of Xew York. These methods cont a i n certain m a t t e r original with t h e a u t h o r , under t h e headings of “ M I X E R A L FILLERS,” “FOREIGX POTASH EXTRACT,” “VULCANIZED RUBBER G C M BY WEIGHT,” and “VULCANIZED RUBBER G U M BY VOLUME.’’T h e method for “ F R E E S U L F U R ”
ALCOHOLIC
is novel in t h e application of a well-known method for total sulfur t o t h e free sulfur determination. METHODS O F TEST
SAMPLES-Samples shall be taken representative of the lots to be tested. BLANKS-Blanks shall be run and deductions made according to the lots of reagents caeces-In the event of any determination not falling within the limits given in the specifications, a check test shall be made before the report is sent out PREPARATION OF SOFT RUBBER-Prepare a sample of not less than 25 grams, taking pieces from various parts of the original sample. The backing of fire hose shall be buffed off before grinding; in all other hose, separate samples of tube and cover shall be made, without removing the backing or friction compound. Other rubber goods built up with friction fabric shall have the rubber layers ground up without removal of the adhering rubber friction. GluNDING-The sample shall be cut into small pieces and then run through the grinder, taking for analysis only such material as will pass a standard 20 mesh sieve. Care must be taken to see that the grinder does not become appreciably warm during the grinding. If the nature of the material is such that i t gums together so that it will not pass through the sieve, as would be the case with undervulcanized samples, i t will be sufficient to pass the material through the grinder twice and accept all the material for the final sample. Crude rubber shall be cut with scissors. Pass a strong magnet through the sample to remove any metal from the grinders, mix thoroughly, and put in tightly stoppered bottles. Do not expose to sunlight or heat. HARD RUBBER-Samples of this material shall be prepared for analysis by rasping REAGENTS-Acetone shall be distilled not more than I O days before use over anhydrous potassium carbonate, using the fraction 56 to 5 7 ’ c . ALco!kolic polash shall be of normal strength, made by dissolving the required amount of potassium hydroxide in absolute
