Composition of Naphtha from Fluid Catalytic Cracking F. W. RIELPOLDER, R . A. BROWN, W. S. YOUNG, AND C. E. NE4DIIVGTON The Atlantic Refining Co.,Philadelphia, P a .
U
TILIZSTION of the newer physical methods during recent years has made available to petroleum technologists a large amount of long sought information on the composition of petroleum and its many products. This information has been invaluable to both the petroleum process chemist and those interested in the chemical utilization of petroleum, but as yct only a fraction of it has found its way into the technical literature. A recent article employs these new techniques for resolving the composition of straight-run naphtha ( 1 ) and some work has been published on the composition of naphtha from catalytic cracking \%Thereinthe analysis was made by hydrocarbon type alone (9, I O ) . Comparisons were made between the composition of virgin, thermal, and catalytic naphthas as determined by a wide selection of physical, chemical, and spectroscopic methods (4) The most complete data available to date (6) results from the work of -1PI Project 6 on a gasoline produced by fixed-bed catalytic cracking (Houdry process). This analysis vias made chiefly by means of fractional distillation, adsorption, and physical property measurement. Considerable grouping, however, was required for the Cg paraffins and no attempt was made to determine individual olefins. The authors present here the results of a study of the composition of a naphtha produced by fluid catalytic cracking. The sample analyzed was the total naphtha from a fluid catalytic cracking unit operating a t 900" F. on synthetic silica-alumina catalyst and a gas-oil charge stock from a mixed crude source. The yield of total naphtha was 33% by volume of the gas-oil charge. Inspection data of the naphtha product are given in the following table: Gravity, OAPI a t 60' r. Boiling range O F. Reid vapor piessure, lb./sq. in. Bromine number Sulfur, wt. % Aniline point, O F. .48TM motor octane number Clear Plus 2 ml. of tetraethyllead Pona analysis" (B) Alkylbeneenes, vol. % Olefins, vol. 7 c 0 Mass spectrometer.
lation through a 100-plate column prior to spectrographic analysis. In some cases olefin analyses were made by a unique combination of fractional distillation, hydrogenation, and spectrometry. The fractional distillation was carried out in completely automatic Heligrid-packed (8) columns varying from 4.5 to 22 mm. in diameter and having from 30 to 100 theoretical plates. Adsorption was done on silica gel in columns (6) varying in size up to 38 mni. in diameter by 6 feet in length. The spectrometers employed were a Consolidated Engineering Corp. mass spectrometer, Model 21-102; a Perkin-Elmel infrared spectrometer, Model 12.4; and a Beckman ultraviolet spectrophotometer, Model DU. Hydrogenation was carried out \+ith Raney nickel as a catalyst in atmospheric pressure apparatus similar to that described by Soller and Barusch ( 7 ) . DISCUSSIOZ OF RESZTLTS
The composition of the naphtha is shown in Table I where approximately 90 individual hydrocarbons are listed in addition to many groups and classes of hydrocarbons. Table I1 sunimarizes these data in terms of hydrocarbon types. Over-all there are 25% paraffins, 10% cycloparaffins, 35% olefins, 6% cycloolefins, and 24% aromatics present in the total naphtha. The follonring table shows the nonhvdrocarbon content of the naphtha:
Component Phenol Cresols Xylenols Sulfur
55.7 94424 8.2 73.4 0.18
68
79.4 83.0 19.3 42
Analytical data are given for over 20 individual olefins and are in other respects also more comprehensive than anything presently available. A total of 152 individual hydrocarbons and groups of hydrocarbons have been determined. METHODS AND EQUIPMENT
The methods employed in this work included mass (S), infrared ( I ) , and ultraviolet spectroscopy supplemented by fractional distillation, adsorption, and hydrogenation. The sequence used for these techniques is given in the flow chart shown in Figure 1 which shows that the naphtha mas first distilled into closely cut fractions corresponding to four different molecular weight groups. These groups were then split according to hydrocarbon type by adsorption on silica gel (Davison Through 200 mesh silica gel No. 22-08 was used in all cases), followed by another fractional distil-
Wt. 70 of Naphtha 0,0006
0.0012 0.0004 0 18
The extent of chain branching occuriing in the noncyclic compounds is given in Table 111. RIonomethyl chains predominate over normal chains by three to one in paraffins but only by a slight margin in olefins. Only minor amounts of dimethyl and ethyl chains are indicated. It was found that straightrehain hydrocarbons with a single methyl group and cyclics with one or more methyl groups constitute more than one third of the naphtha. Cyclic compounds, exclusive of aromatics have been classified according to ring structure in Table IV, where it will be observed that five-membered rings outnumber six-membered rings by a factor of three or more in both paraffins and olefins. The position of substituents in cycloparaffins is indicated in Table I-, showing that in disubstitution the 1,3-position is favored whereas 1,2,4-substitution predominates among the trisubstituted compounds. A comparison was made of the data with those published on an East Texas virgin naphtha ( I ) and a naphtha from fixed-bed catalytic cracking (6). In Table VI i t is seen that for both catalytic naphthas monomethyl chains predominate over normal chains by five to one while the straight-run naphtha shows nearly equal amounts of monomethyl and normal chains. The ratio of cyclohexane t o cyclopentane derivatives also appears in Table VI showing a decrease in values from one for straight-run naphtha to 0.6 for fixed-bed catalytic naphtha and t o 0.3 for fluid bed catalytic naphtha. However, the possible differences be1142
May 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
1143
TABLE I. COMPOSITION OF TOTAL NAPHTHA
Propane Isobutane n-Butane Isopentane n-Pentane 2,2-Dimethylbutane 2 3-Dimethylbutane 2:Methylpentane 3-Methylpentane n-Hexane 2 8-Dimethylpentane 2:4-Dimethylpentane 2,2,3-Trimethylbutane 2 ,&Dimethylpentane 2-Methylhexane 3-Methylhexane 3-Ethylpentane n-Heptane 2,2,4-Trimethylpentane 2,2-Dimethylhexane 2,5-Dimethylhexane 2,4-Dimethylhexane 2,2,3-Trimethy'lpentane 3 3-Dimethylhexane 2'3 PTrimethylpentane 2'3'3-Trimethylpentane 2:3:Dimethylhexane 2-Methyl-3-ethylpentane 2-Methylheptane PMethylheptane 3 4-Dimethylhexane 3lMethyl-3-ethylpentane 3-Ethylhexane 3-Methylheptane 2 2 4 4-Tetramethylpentane 2:2:5:Trimethylhexane n-Octane 2,2,4-Trimethylhexane CO +
Boiling Point a t 1 Atm., ' F. PARAFFINS -43.7 10.9 31.1
270-306 306-358 358-391 391-higher
C~CLOPARAFFINS 120.7 Cyclopentane 161.3 Methylcyclopentane Cvclohexane 177.3 _ _ ~~ ..~ . . ~ 190.1 1 1-Dimethylcyrlopentane I:trans-3-Dimcthylc clopcntnne 1 ,~is-3-Dimethylcyc~opentane 1 .trans-2-Dimethylcyciopentane 197.4 1,cis-2-Dimethylcyclopentane 211.2 213.7 Methylcyclohexane 218.2 Ethylc clopentane 820.8 1 1 3-~imethylcyclopentane l'&ns-2 cis-4-Trimethylcvclo~entane 228.7 1 'trnns-2'cis-3-Trimethv 230.7 236.7 i ;i,r-Trimethylc;clo,"ntane 242.1 1.cis-a.trari 9-4-Trimethylcyclopentane 1,czs-2,~rane-3-Trimethylcyclopentane 243.9 244.0 1 cis-Z,eis-~-Trimeth,.lcyclopentane 246 8 1,trans-4-Dimethylcyclohexane 247.2 1 1-Dimethylcyclohexane 248.2 1:cis-3-Dimethylcyclohexane 248.4 1-Methvl-cis-3-ethvlovclo~entane 249.4) 250.1 250.7 253.4 I&olopentane :Iohexane 254.2 255.8 1 ,cis-4-Dimethylcyclohexane 256.0 1,trans-3-Dimethylcyclohexane 259.6 Isopro ylcyclopentane 262.4 1-Met 1-cis-2-ethylcyclopentane 1,cis-2%methylcyclohexane 265.5 CS+cycloparaffins 270-306 306-358 358-391 39 1-higher Dicycloparsffins 270-306 306-358 358-391 391-higher
;E;: 2)
Isobutene 1-Butene trans-Z-Butene cis-2-Butene 3-Methyl-I-butene 1- entene ethyl-1-butene trans-2-Pentene cia-2- Pentene 2-Methyl-2-butene 3,3-Dimethyl-l-butene %Methyl-1-pentene 2 3-Dimethyl-1-butene LMethylpentenes 2-Methyl-1-pentene 1-Hexene 2-Ethyl-1-butene
2-b
OLEFINS 19.6 20.7 33.6 38.7 68.1 86.0 88.0 97.6 98.8 101.3 106.2 128.8 132.2 129-131 144.0 146.4 148.9
VOl. %jof Naphtha
Boiling Point a t 1 Atm., O F. OLEFINS(Concluded)
0.13 0.81 1.32 5.55 1.14 Not found 0.70 1.71 1.31 0.43 Not found 0.22 Not found 0.088 0.77 0.77 Not found 0.46 Not found Not found 0.20 0.11 Not found Not found Not found Not found 0.10 Not found 0.41 0.13 0.10 Not found 0.048 0.43 Not found Nbt found 0.22 Not found 1.17 1.96 1.48 2.92
2-Methyl-2-pentene cis- and trans-3-Hexene cis- and trans 2-Hexene cis- and trans:3-Methyl-Z-pentene 2,3-Dimethyl-2-butene 2.2-DimethylpentenesQ 2 3-DimethylpentenesQ 2'4-Dimethylpentenesa 2:Methylhexenesa 3-Methylhexenesa 2-Ethylpentenesa 3-Ethylpentenes" n-HeptenesQ Trimethylpentenesa Dimethvlhexenesa 9-Met hylheptenesQ 3-Methylheptenes" 4-Meth Iheptenen" 3-Ethylxesenesa n-Octenes CO, olefins
0.14 0.96 0.12 0.053 0.36 0.18 0.11 0.35 0.20 0.061 0.072 0.057 0.010 0.096 0.019 0.035 0.074 0.024 0.13 0.28 0.021 Not found Not found 0.050 0.060 0.066 0.022 0.031 0.004 0.93 1.43 1.08 2.11 0.01 0.18 0.16 0.50
C- dicycloolefins
0.91 0.64 1.35 1.05 Not found 1.20 0.71 0.43 3.97 4.61 0.21 0.27 0.98 Not found 0.61 0.57 0.25
Cyclopentene Methylcycl~pentenes~ Cyclohexene 1,l-Dimethylcyclopentenesa l.2-Dimethvlcvclo~entenes~
255-322 322-359 359-higher
CYCLOOLEFINS 111.4 151-1 69 181.8
... ... -1 ,.. ,..
...
... ... .
[ethyl-1-ethylcycl~ntenes~ 1-Methyl-2-ethylc clopentenesa 1,2-Dimethylcyclo~exenesQ 1,3-Dimethylcyclohexenes~
1,4-Dimethylcyclohexenes~ Cet cycloolefins
.
I
:::I ...
256-322 322-359 359-higher 259-higher
VOI.
% of
Naphtha 0.85 1.79 2.55 0.40 0.006 0.48 0.11 1,24 1.42 0.13 1.20 0.41 0.45 0.73 0.40 0.088 0.23 2.55 0.96 1.24 0.40 0.75 0.015 0.012 1.58 0.42 0.26 0.48 0.051 0.047 0.14
0.16 1.56 0.20 0.18 0.08
ALICYLBENZENES Benzene Toluene Ethylbenzene o-Xylene *Xylene p-Xylene Isopropylbenzene n-Propylbenaene Methylethylbenzenes Trimeth lbenzenes CjHrC$o CsHs-CsHu CeHrCsHia C~HE-C~HII
176.2 231.1 277.1 292.0 282.4 281.0 306.3 318.6 322-329 328-349 336-401 338-higher 387-higher 430-higher
ALKENYL BENZENE0
AND/OR
0.21 2.32 1.07 1.20 2.30 0.84 0.18 0 16 0.96 4.98 3.90 1.78 0.56 0.052
CYCLOPARAFFIN-AROMATICS
DICYCLICAROMATICS Dicyclic aromatiw Total Q
1.3 100.0
Indicates molecular structure without regard to double bond position.
tween the naphthas may be due to crude source &s well as treatment in refining operations. The Csalkylbenaene analysis is compared with values calculated from thermodynamic data (11)in the follo&ng table:
Actual Ethylbenzene o-Xylene *Xylene pXylene
19.8 22.2 42.5 15.5
Relative Vol. % Calcd. (11) 9.7 22.6 46.7 21.0
It is seen that a significant difference is shown between actual and theoretical values for ethylbenzene but the individual xylene comparisons are reasonably close.
Vol, 44, No. 5
I N D U S T R I A L A N D E N G IN E E B I N G C H E M I S T R Y
1144
Distillation
I
0 Aeavicr
Adsorption
I Olefina
1
Disfillation
Distillation
r
I
1
Vaes Spectrometer
Spectrometer
4
4
Infrared ::ass Spectrometer
Vasa Spectrometer
4
u1 t r a v iolet
TQe AMlYSll
Ma S8 Spectrcnetsr
rrw Analysis
Figure 1. Scheme of Analysis
METHODS OF ANALYSIS
visible in the higher molecular weight fractions. The interface between hydrocarbon and alcohol was indicated by an orange dye, Patent Chemicals, Inc., Body Color No. 1. The pentene portion was then distilled into three fractions having boiling ranges of 40 to 57" F., 57" t o 97" F., and 97" to l t 5 ' F. The pentanes were determined by a mass spectrometer analysis on the Cg fraction from the primary distillation. The pentene analysis, however, was made by both mas8 spectrometer and infrxred analyses of the three pentene fractions. The CSportion of the naphtha from the priC, FRACTION. mary distillation was percolated through silica gel at 32" F. to separate the paraffins and cycloparaffins from the olefin8 and cycloolefins. The former were then determined on the saturated fraction by a mass spectrometer analysis and the unsaturated fraction from the percolation was distilled with the best available fractionation into three fractions with boiling ranges of 115" to 140" F., 140" to 151" F., and 151Oto 165" F. These fractions were then hydrogenated after shaking with mercury to remove sulfur. NAPHTHA T A B L E 11. SUbIMARY O F h . I L Y S I S O F TOTAL Because of the unavailability of all of the pure olefins in the CS and higher molecular weight Cs and C4 and €%ydrocarbon Type Lighter '' " C7 'leavier range, i t was impossible to make a direct mass or Paraffin 2 ..2. 6 0.14 6.69 4.15 1.08 2.31 1.25 1.75 1.11 7.53 5.55 infrared analysis of the unsaturated fractions. Monocyclopara5n Dicycloparaffin .'. . '. .. 0.85 0.85 The method of analysis used here was therefore to Olefina 3.'95 l0:hZ 8.48 4.59 2.31 4.75 36.00 Cycloolefin .. 0.40 0.77 2.27 0.87 1.94~ 6.25 fractionate and then hydrogenate the olefins. The ... ... ... . .. 0.09 Dicycloolefin .. , o. 21 2.32 5.41 12,57 2::;: hydrogenated products were next analyzed on the Monocyclic alk 1 aromatic .. Monocyclic alzenyi aromass spectrometer. These data then gave a conimatic and/or cyclopar.. ... . .. ... . .. 2.18 2.18 bined value for olefins having each different spatial affin-aromatic Dicyclic aromat,ic .. . .. ,.. . ,. . .. 1.30 configuration, but they did not distinguish between Total 6.21 18.15 14.69 12.74 11.45 36.76 100.00 having the s&me configurationbut
The methods of fractionation and analytical procedures are summarized in the flow diagram shown in Figure 1. The first step was t o distill the naphtha into four different molecular weight groups. Utilizing the C? fraction from the primary disC,FRACTION. tillation, individual butane and total butene determinations were made on the mam spectrometer. The individual butenes were then calculated from the infrared spectra. The Cg fraction from the primary distillation Cg FRACTION. was first percolated through silica gel at 20' F. t o separate pentenes from pentanes. The cut point between these groups was made visible by the addition of a yellow dye to the mixture. The dye was isolated by chromatography from a commercial oil dye, Patent Chemicals, Inc., Oil Color (2-48. Another component in this dye also made the cut point between olefins and aromatics
2i,":!p
, ,
Q
Includes diolefin6 and acetylenes.
TABLE 111. CHAIS BRANCHING IN NONCYCLIC HYDROCARBONS Volrinie % of Naphtha Fraction c4
C6 C6
C7
CE
Total a
Normal
1,32 1.14 0.43 0.46
Paraffins Monomethyl Dimethyl 0.81
5.55
..
0.22
0.97
0:70 0.31 0.50
3.57
11.89
1.51
3.02 1.54
Includes kimethylpentenes.
Ethyl
Normal
.. .' ..
3.04
0:05
0.05
0.23 12.43
Olefins Monomethyl Dimethyl 0.91
5.60 2.36
5.32 4.28
1.20
2.66
1.58 14.75
... ...
1.59 0.60
0.41a 2.60
Ethyl
.. O:i5 0.13 0.09
0.47
different double bond locations. Fortunately, in the case of Cg hydrocarbons. many of the olefins with different double bond locations have boiling points widely enough apart so t h a t n o more than one. of each spatial configuration falls in each of the fractions indicated above. Where this is the case it will be possible to determine each individual olefin in the mixture. Reference to Table I will show that the exceptions to thi8 are the 4methylpentenes, 2- and 3-hexene, and
May 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
TABLE IV. fraction
CK
114.5
consisting of paraffins, olefins, monocyclic aromatics, and dicyclic aromatics, respectively. The paraffin portion was then distilled again using the best fractionation available and the C, paraffins and cycloparaffins were taken Over in the first three fractions. These were analyzed
DISTRIBUTION OF CYCLIC HYDROCARBONS
Volume % of Naphtha Paraffins Olefins Cyolopentanes Cyclohexanes Cwlopentanes Cyclohexanes 0 40 0 14 0.96 0 12 0 76 0 03 0 91 0 35 1 85 0 42 0.70 0 40 0 67 0 20 2.71 0 87 3 68 0 65
for the individual compounds shown in Table I by means of the mass spectrometer, The c8 saturates were taken overhead in the next 10 fractions; they were then analyzed by means of both their mass and infrared spectra. The composition of the individual c8 fractions is shown in Table VII; the composited results TABLB V. SUBSTITUTION IN CYCLOPARAFFINS are included in Table I. Finally the CBand heavier saturates Volume % of Naphtha were collected in four broad fractions and were analyzed on the Disubstituted Trisubstituted fraction 1,l 1,2 1,3 1,4 1,1,2 1,1,3 1,2,3 1,2,4 mass spectrometer (8) t o yield the paraffin-cycloparaffin-dicyclocia 0 05 0 29 0.36 paraffin split shown in Table I. C8 0 02 0.11 0 47 0.13 0 01 0 06 0 08 0 20 The unsaturated portion of the C7 and heavier fraction was dis0 01 0 06 0 08 0 20 Total 0.07 0.40 0 83 0 13 tilled next, the fractions were hydrogenated, and 5 Consists of cyclopentanea only. the C7 and Csolefins were determined b y the same technique as was described for the Cg olefins In AND RING STRUCTURE TABLE VI. EFFECTOF ORIGIN ON CHAIN BRANCHING this CaRe,however, boiling were so close toStructures gether that only groups of olefins of given spatial Chain Branching (Relative Amounts) Amounts) MonoDiCyclopentane Cyclohexane configuration could be identifed. They are SO Normal methyl methyl Ethyl derivatives derivatives listed in Table I. The three fractions of CSand East Texas virgin na htha (1) 1 0 9 0 2 002 1 1 heavier unsaturates were analyzed on the mass Fixecf-bed catalytic na htha (6) 1 5 4 1 5 1 0.6 spectrometer for the olefin-cycloolefin split (9). F l u i f bed catalytic The aromatic portion was fractionally distilled naphtha 1 5 3 1 4 003 1 0 3 and all analyses except t h a t for individual xylenes were made on the mass spectrometer. The C8 alkylbenzenes were analyzed by ultraviolet specall cis-trans isomers. Because of the method of analysis used, trophotometry. No attempt mas made to split the Cl0 and it will be apparent that any diolefin present will be reported as higher aromatics except to differentiate the alkylbenzenes from the corresponding olefin the sum of alkenylbensenes and cycloparaffinbenzenes. The C7AND HEAVIER FRACTION.I n order t o enhance the results of dicyclic aromatics were identified by their odor (characteristic the percolation of this portion of the naphtha i t was distilled into naphthalene odor), behavior on silica gel, and refractive index. three cuts (not shown in Figure l),which were subsequently perThe analysis of the naphtha was found to be self consistent colated through silica gel and composited to yield four portions with the exception of the higher boiling paraffin-cycloparaffin c 6
c 7
CB Total
TABLE VII.
INFRARED
ANALYSIS O F C8 DISTILLATE FRACTIONS
-
Volume % of Total Naphtha Boiling Point, Boiling Range of Fraction O F. F . i16-226 226-235 235-238 238-245 245-247 247-249 $49-250 250-253 253-265 255-258 Hydrocarbon 213.7 0.021 0.005 M etliyloyclohexane ... ... ,.. ... ... 218.2 0.036 0.027 E t h lcyclopentane ... ... ... ... ... 220.8 0.019 0.010 1.1,f-Trimethylcy clopentane 0: 001 ... .. .. ... .. 224.3 0 0 0 2,2-Dimethylhexane ... .. ... .. ... 228.4 0.039 0.058 0,009 2 &Dimethylhexane ... ... ... . . ... 0.017 0.043 0.006 l~trans-2,czs-4-Trimethyl~~clopentaue 228.7 ... ... ... ... , . . 229.0 0.048 0.'016 0.024 2,4-Dimethylhexane ... ... , . . . . , . 229.7 0 0 0 2,2,3-Trimethylp$ntane ... . . ... ... . . 230.7 0.010 0.036 0.011 1,tians-2 ,cis-3-Tr1methylcyclopentane ... ... ... , . . ... 233.6 0 0 3,3-Dimethylhexane 0 ,.. .. ... ... ... 236.3 0 0 2 3 4-Trimethylpentane 0 , . . , . . 236.7 0.006 0.005 0 1:1:2-Trimethylcyclopentane ... , . , . . , . . ... 238.6 0 0 2,? 3-Trimethylpentane 0 ... . . ... 240.1 0 0.010 0.028 Z,$:Dimethylhexane 0: 050 olOi2 ... , . ... ... 240.2 ... 2-Methyl-3-ethylpentane 0 0 0 ... ... ... 242.1 ... ... 0.007 1,cis-2,trans-4-Trimethyloyolopentane 0.059 0.024 , . . ... .. 243.8 ... . , . 0,016 0.162 0.145 2-Methylheptane ... , . ... 0 088 ... , . ... 0 0.004 0 015 0 ... . , . 1,cis-2,trans-3-Trimett6Jlloyclopentane 243.9 ,.. ... 243.9 ... ... 0.054 0.048 4-Methylheptane 0 ... ... ... 0 025 243.9 ... ... ... 0.036 ... .. 3 4-Dimethylhexane 0.048 0 015 0 003 ... ... 244.0 ... ... 1~cis-2,cis-4-Trimethylcyclopentane ... 0 , . . .. 0 029 . . 244.9 ... , . . ... 0 3-Meth 1-3-ethylpentane ... 0 0 0 . . . ... 245.4 ... ... 0.014 3-Eth g e x a n e 0.024 ... 0 0 010 246.1 ... ... , . . 0.077 3-~etXylheptane 0.093 0 121 0 118 0:024 ... 246.8 ,.. ... 1 t~ans-4-Dimethylcyclohexane ... 0 042 0.010 0 022 , . . 247.2 ... .,. I ' 1-Dimethylcyclohexane ... 0:004 0 004 0 014 0.001 0 : b61 ... 248 2 1:cis-3-Dirnethylayclohe~ane ... .., 0 0.023 0 037 0 066 0 248.4 1.Methyl-czs-3-ethylcyclopentane ... . . . 0.007 0.087 0.067 0.057 0.062 "360 * - . -d .. ... 1-Methyl-trans-3-ethylcyclcpentane 0.007 0.006 ~-Methyl-trans-2-ethylcyclopentan~ 250.1 .. , . . 0.004 0.004 0 ... ... ... 250.7 , . . ... ... ... 0 0 I1 1,l-Methylethylcyclopentane ... ... 252.1 .., ... ... . , , 0 0 2 2 4 4-Tetramethylpentane 0 6 1 '&'2 cis-3-Trimethylpentane 253.4 , . . . , . ... ,. . . , , . . ... 0 0 aD ... ... ... 254.2 ... ... .. 0.007 l:tran~-2-Di1nethylcyclohexane 0. 012 Q.031 255.4 ... ... ... ... ... ... ... 0 2,2,5-Trimethylhexane 0 1D ... ... ... 1,cis-4-Dimethylcyclohexane 255.8 ... ... , . . .. 0.006 0 . 010 0.044 ... ... ... ... 1,t~ans-3-Dimethylcyclohaxane 256.0 ,.. ... ... 0.001 0.012 0 . 0 5 3 258.2 .. 0.028 0 . 1 9 3 n-Octane 259.6 , , .. Isopropylcyclopentane 0.022 2 , 4-Trimethylhexsne ~ 259.8 ... ... ... 0 l-?,lethyl-cis-2-ethylcyclopentane 262.4 .,, ... ... 0 031 1,cis-2-DirnethylcyclohexrPne 265.5 .. , ... , . . 0 004 a Additional quantitias of these hydrocarbons found in lower boiling fractions. 6 Small additional quantities of these hydrooarbons probably present in higher boiling fractions. .
.
I
I . .
\
'
Total 0 . 026a
0.063a 0 . 030a Not found O.lOBa 0.066a 0.088a Not found 0.057" Not found Not found Not 0.010 found 0.100
Not found 0.090 0.411
0.019 0.127 0.102 0,029 Not found 0.048 0,433 0.074 0.024 0.126 0.280 0,021 Not found Not found Not found 0.050b Not found 0.060b, 0.066 0.221b 0.022b Not found 0 031; 0 004
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
1146
TABLEl T I I I .
Boiling Range of Fraction, F.
C O M P A R I S O N O F CYCLOP.4RAFFIN
CONTENT OF
FRACTIONS
cs AND HEAVIER
Vol. 44, No. 5
for dicycloparaffins produced a laigc change in the refractivity interccpt determination for paraffins.
(By mass spectrometer analysis and refractivity intercept method) Volume % of Saphtha Uncorrected Corrected6 MonocyoloDicycloCycloCycloParaffins paraffins paraffinsa Paraffins paraffins Paraffins paraffins
LITERATURE CITED
(1) Bell, M. F., A n a l . Chem., 22, 1005 (1950). (2) Brown, R. A , Zbid., 23, 430 (1951). REFRACTIVITY I N T E R C E P T hf E T H O D MAE^ SPECTROYETER ANALYSIS (3) Brown, R. A,, Taylor, R. C., Mel56 44 0 57 43 57 43 270-306 polder, F. W., and Young, W. S., 306-358 55 40 5 44 56 54 46 Zbid., 20, 5 (1948). 54 40 6 33 67 46 54 358-391 391 and higher 53 38 9 25 75 45 55 14) Cady, W. E., AIarschner, R. F.,and Cropper, W . P., payer presented a t a M a y also include small amounts of tricycloparaffins. b Refractivity intercept of the cycloparaffins corrected for the presence of dicycloparaffins indicated 119th Meeting, AM. CHEM.SOC., in mass spectrometer analysis. Cleveland, Ohio, April 1951. ( 5 ) Glaspow. A. 11.. Willinpham. C. B.. a n d Rossini, F. D.; IND. ENG. CHEM.,41, 2282 (1949). (6) Whir, B. J., J. Reseaich Natl. Bur. Standards, 34, 435 (1945). fractions. -4serious discrepancy is shown in Table VI11 between (7) Noller, C. R., and Barusch, h.1. R., IND. ENG.C H m f . , API'AL. ED., the paraffin-cycloparaffin splits in the C Qand heavier distillate 14, 907 (1942). fractions boiling above 306" F. as calculated by the mass spec(8) Podbielniak, W. J., Zbid., 13, 639 (1941). (9) Rampton, H. C., J . Znst. Petroleum, 35, 42 (1949). trometer and refractivity intercept methods. I t is believed t h a t (10) Starr, C. E., Tilton, J. A , , and Hockberger, W. G., END. KNG. much of this difference is due t o the presence of dicycloparaffins CREM.,39, 195 (1947). and possibly tricycloparaffins which are shown in Table VI11 t o (11) Taylor, W. J., Wagman, D. D., Williams, M. G., Pitzer, K. S., as high as 9% in one fraction. The data of Ward and Kurta ( 1 2 ) and Rossini, F. D., J . Rrseurch N a t l . Bur. S t a d w d s , 37, 95 (1946). show that the difference in refractivity intercept between paraffins (12) Ward, A. L., and Kurts. 8. S.,IND. ENG.CHEY.,.ANAL. ED.,20, and dicycloparaffins is several times greater than t h a t between 559 (1938).
paraffins and monocycloparaffins. By correcting the value of the refractivity intercept of cycloparaffins for the presence of dicycloparaffins, a fair agreement was reached between the two methods of analysis for paraffin content. Exact agreement can hardly be expected since a small deviation in the mass spectrometer analysis
RECEIVED for review May 2, 1951. -4CCEPTED December 31, 1961. Presented as part of the Symposium cn Composition of Petroleum and Its Hydrocarbon Derivatives presented before the Division of Petroleum Cliernistry at the 119th Meeting of the . 4 ~ E ~ l c . 4C3H E Y I C A I . EOCIETY, Cleveland, Ohio, April 1951.
Solubility of Hydrogen, Oxygen, Nitrogen, and Helium in Water AT ELEVATED TEMPERATURES H . A. PRAY, C. E. SCHWEICKERT, AND B. H . R/IIYVIvICH1 Battelle iMemorial I n s t i t u t e , Columbus 1 , Ohio
THE 1
i n c i d n g application of high temperaturesand pressures
to various processes has made a knowledge of the solubilities
of compressed gases in water necessary for purpoises of engineering design. A survey of the literature has revealed that considerable data are available on the solubilities of gases under partial pressures of more than 25 atmospheres and a t relatively low temperatures. Data in the region from about 5 to about 25 atmospheres and from about 125' F. t o temperatures near the critical point of water are very meager and incomplete. A determination of the solubilities of oxygen, hydrogen, helium, and nitrogen in water a t temperatures from 128" to 650" F. and a t presmres up to about 500 pounds per square inch absolute was,therefore, undertaken. E X P E R I M E N T A L PROCEDURE. For determining the solubilities of gases in water, the apparatus shown in the schematic diagram (Figure 1) was used. A typical example of the use of this apparatus is as follows: Valves A and B are closed, valves C and D are opened, and the 3-liter bomb contained in the rocking autoclave, E, is evacuated by means of the vamum pump, F. Valve A is then opened and about 1500 ml. of distilled water are admitted to the bomb from 1
Present address, Naval Ordnance Testing Station, Inyokern, Calif.
INLET
Figure 1. Diagram of Solrability Apparatus
