1098
INDUSTRIAL AND ENGINEERING CHEMISTRY
rate constants were not presented, their data are of significant interest and demonstrated increased resistance of polyethylene to scission-type reactions in the absence of oxygen. An evaluation of initial and minimum rate constants in Equation 8 for D Y N H involved in this work and for constants calculated from data reported by Pardun (IS), Jellinck (79,and Tobolsky ( 1 7 ) is shown in Table I. Obviously, reaction rates, k , cannot be compared in Table I because of differences in units and differences in conditions of the degradative processes applied. However, activation energies, E, and temperature coefficients of reaction rate, k‘+loc./kt, derived from ratios of reaction rates, are independent of units and can be compared. Temperature coefficients of reaction rate and activation energies of oxidation of polyethylene DYNH, Fisher-Tropsch wax, and vulcanized natural rubber are roughly comparable. Also, activation energies and frequency factors found in these specific cases are in the same order of magnitude of the values (23,000 cal. mol.-1 and 105) reported by Eyring et al. ( 2 ) for oxygen-catalyzed isomerization and polymerization of substituted ethylenes. On the other hand, polyethylene resin depolymerized in the absence of oxygen at much higher temperatures displays a higher energy of activation of scission-type degradation which is characteristic of increased stability. ACKNOWLEDGMENT
Aid extended by 1,. H. Wartman and F. M. Rugg in making the reported infrared spectrophotometric measurements, and by G. A. Crowe and other associates of the author is gratefully acknowledged.
Vol. 44, No, 5
LITERATURE CLTED
Bolland, J. L., and Gee, G., Trans. Faradag Soc., 42, 2 3 w 4 (1946). Eyring, H., Hulburt, €1. AI., and Harman, R. A . , ZND. ENQ, C F I E M . , 35,511-21 ( h k y 1943). Getman and Daniels “Outlinea of Physical Chemistry,” 7th ed., p. 363, New York, John Wiley & Sons, Inc., 1943. Jackson, W., and Forsyth, J. S. A., J. I n s t . Chem. EWTS.,Pt. 111, 91, 23 (1949). Jackson, TV., and Forsyth, J. S. A, J . Inat. EEec. Eiigrs. (London), Pt. I l l , 91 (June 1944). Ibid., 94, 55 (1947). Jellinck, H. H. G . , J . Polgmer Sci.,4, 1-36 (1949). Madorsky, S. L., Straus, S., Thompson, D., and Williams, L., Ibid., 4, 639-64 (1949). hlaibauer, A. E., and Myers, C. S.,TTans. Electrocha. SOC.,90. 449-67 (1946). Morawete, H., IND.ENG.CHEM.,41, 144247 (July 1949). Myers, C. S., and Rfaibauer, A. E., Elec. Eng., 64, 916-18 (December 1945j. Oakes, W. G., and Richards, R. G., J. Chem. Soc., 1949,2929-35. Pardun, H., Fette u. Seifen, 48,397-403 (1941);49, 441-6 (1942). Pross, A. W., and Black, R. A I . , J . Sop. Chem. I d . (London),69, 113-6 (April 1950). Stossel, E., Oil Gas J., 43, 130-9 (July 21, 1945), 145-51 (August 18, 1945), 69-74 (September 1945). Thompson, H. W., and Turkington, P., Trans. Faraday Soc., 41, 246-60 (1945). Tobolsky, A. V., Mete, D. J., and Mesrobian, R. B., J . Am. Chem. Soc., 72, 1942-52 (May 1950). Wangsgard, A. P., and Raeen, T.,Trans. Elactrochem. Swc., 901, 177-91 (1946). RECEIVED for review May 31, 1951.
ACCEPTEDSorexukr 13, 1961,
Alcohol as an Antiknock Agent in Automotive Engines JAMES C. PORTER AND RICHARD WIEBE Northern Regional Research Laboratory, Peoria, Ill.
A
LCOHOL-water injection in automotive engines for the purpose of improving the octane rating of gasoline a t high engine loads has received considerable attention in recent years (9, I S , 17). I n military aircraft alcohol-water injection was used extensively during the last war both for take-off and in combat operations (10). h very complete set of references will be found in “The Technical Literature of Agricultural Motor Fuels” ( 1 6 ) and subsequent papers of this laboratory ( 7 , 8, 1 7 ) . It is principally the high octane number of alcohol which determines the high antidetonant quality but the cooling effect of the high heats of vaporization of alcohol and of water are import a n t contributing factors. Table I shows the physical properties of the three lower alcohols, of water, and of a 50-50 mixture by volume of ethyl alcohol and water. If the heat of vaporization of gasoline is assumed t o be approximately 130 B.t.u. per pound, the heat of vaporization of a 50-50 mixture by volume of ethyl alcohol-water is almost six times as large. An additional cooling factor is the lower maximum combustion temperature when alcohol is used, as shown in Figure 1. The maximum temperatures, as well as thermal efficiency, were calculated from the thermodynamic data reported by Hershey, Eberhardt, and Hottel (6) and Hottel, Williams, and Satterfield ( 6 ) for iso-octane and Wiebe, Schulta, and Porter ( 1 8 ) for ethyl alcohol. See Table I of (18) for data on gasoline and alcohol at a compression ratio of 6 t o 1. The 25’% alcohol-gasoline blend data were obtained by interpolation. Results a t the other compression ratios up t o
12 to 1 were calculated in a similar manner. An initial temperature of 80” F. (540’ R.) and complete initial vaporization of the fuels were assumed. LABORATORY AND ROAD OCTANE NUMBERS W I T H ALCOHOL
I n order to obtain a better understanding of the effect of alcohol on hydrocarbon fuels, four base stocksstraight-run, catalytically cracked, thermally cracked, and polymer gasoline-were selected which were similar to the ones used by Bogen and Nichols ( 1 ) in their work “Calculating the Performance of Motor Fuel Blends.” The results for the four base stocks and their mixtures, given in Tables I1 and 111, show an excellent response to additions of ethyl alcohol except in the case of the straight polymer. Here the octane values approach the rating of pure ethyl alcohol (iso-octane and 0.33 ml. of tetraethyllead, for the Research and 92.0 for the Motor Method), and little or no further gain can be expected. As indicated in the tables, the octane number determinations were made on blends; however, the engine will not react differently if the alcohol is introduced by injection rather than as a blend. The actual potential performance gain is not given on the octane number scale but on the so-called performance number scale (4), to which further reference will be made. On this more realistic scale a n octane unit in the upper range assumes a much greater importance than one in the lower range. I n general, the Research Method octane number is characteris-
May 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
1099
ratio). It is also shown in Figure 2, where a comparison is made between the Borderline ratings at 1000 Lower Heat of and 2500 r.p.m. and the two laboratory ratings. At Heat of Vapori- Vapor 2500 r.p.m. the road octane number of alcohol blends Combus- ration Prestion a t at sureat Liquid Lb. d n t i LIolecu250c., 250c looo F,, ~ e n s i t y , deton&/ is considerably higher than the corresponding Motor lar B.t.u./ B.t.u:) Lb./ G./M1., Lb. Method ratings at the high compression ratio, as Antidetonant Weight Lb.a Lb. Sq. In. ’:d Air b 32,04 9,028 502 4.45 o.78686 o.154 shown in the lower right-hand corner of Figure 2. Methanol Ethyl alcohol 46.07 11,955 395 2.36 0.78506 0.110 At 3000 r.p.m., however, Borderline ratings of the Iaopropyl alcohol 60.09 13,255 318 1.82 0’7812 O’Og7 Ford 6 drop sharply and are lower than the Motor Ethyl alcohol 50%-%7ater 50%. by vol. 5 080 771 1.72 0,92623 0.250 Method ratings; this drop is particularly noticeable 18.02 0 1048 0.95 0.99708 .. Water in case of the alcohol blends. For example, in a blend a Constant volume in gaseous state. b For chemically correct reaction. of 90% catalytically cracked mixture, 10% polymer, arid 3 ml. of tetraethyllead with 25% ethyl alcohol (Table 111), the Borderline octane number at 3000 r.p.m. for the Ford 6 engine is 71.8, while the Motor Method THROTTLE0 CYCLE UNTHROTTLED CYCLE 55 5200 rating is 84.8. For the high compression ratio engine the figures are 92.0 and 84.8, respectively, an opposite extreme. . I n Figures 3 and 4 the Research and Motor Method octane 5 0 p : 00 numbers of the four base stocks from Table I1 are plotted as functions of tetraethyllead and alcohol content. It is interesting, of U c” course, to note the good response to both lead and ethyl alcohol. 45000 g45 /’ 5000 ;-45 // / Efficiency The data in Tables 11,111,and IV, changed t o performance numz w 0 w Efficiency hers, were used in Figures 5 and 6 where the gain in performance 0 i 4 0 / --Gasoline 4900 numbers for various leaded and unleaded fuels is shown as a, 40 / -Gasoline function of octane numbers when 25% ethyl alcohol by volume -75%Gosoline --75X Gosoiine Plus 25% Ethanol Plus 25.bEthanol is added to the same fuels. Cracked stocks are least responsive 35 35 10 12 8 8 10 le to a 25% addition of ethyl alcohol, while reference fuels and senCOMPRESSION RATIO COMPRESSION RATIO siiive reference fuels show the best’ results. Commercial grades, Figure 1. Calculated Maximum Temperatures and Effi- as ,,.onid be expected, fall in betffeen, ciencies for Gasoline and for a 25% Alcohol Blend as a Function o f Compression Ratio
PROPERTIES OF VAR~OUS ANTIDETONANTS TABLE I. PHYSICAL
4’
~~~~
k
’
’
-
s
tic of the !ow speed range and the Motor Method octane number of the high speed range. That this is true to a large extent is shown in Tables I11 and 117 in which the “Borderline” (3)and “Modified Uniontown” ( 1 4 , 16) road octane numbers are given for a standard Ford 6 (6.8 to 1 ratio) and for an Oldsmobile 98 with a General Motors Co. high compression engine (10 to 1
f
80
g 85
s 7 5 W (r
0
----.----
TABLE 11. KNOCKRATING OF ETHYL ALCOHOL BLENDSWITH FOURBASE STOCHS Fuel Description, % by 1701. Straight-run Straight-run plus 1 ml. tetraethyllead Straight-run plus 3 ml. tetraethyllead Straight-run plus 10 ,, ethyl alcohol Straight-run plus 26% ethyl alcohol Straight-run. 1 ml. tetraethyllead, plus 25% ethyl alcohol Straight-run, 3 rnl. tetraethyllead, plus 25% ethyl alcohol Catalytically cracked Catalytically cracked plus 1 ml. tetraethyllead Cqtalytically cracked plus 3 ml. tetraethyllead Catalytically cracked plue 10% ethyl alcohol Catalyticitlly cracked plus 2 5 % ethyl alcohol Catalytically cracked, 1 rnl. tetraethyllead. plus 25% ethyl alcohol Catalytically cracked, 3 ml. tetraethyllead, plus 25% ethyl alcohol Thermally cracked Thermally cracked plus 1 ml. tetraethyllead Thermally cracked plus 3 ml. tetraethyllead Thermally cracked plus 10% ethyl alcohol Thermally cracked plus 25% ethyl alcohol Thermally cracked, 1 ml. tetraethyllead. plus 25% ethyl alcohol Thermally cracked 3 ml. tetraethyllead, plus 25% ethyl alcohbl Polymer Polymer plus 1 ml. tetraethyllead Polymer plus 3 ml. tetraethyllead Polymer plus 10% ethyl alcohol Polymer plus 25% ethyl alcohol Polymer, 1 ml. tetraethyllead, plus 25% ethyl aloohol Polymer, 3 ml. tetraethyllead, plus 25% ethyl alcohol
Research Method, ASTM D 908-48T
40.0 52.7 64.0 56.4 69 5
82.0
78.0
88.3 85.7
82.7 74.0
90.8
79.1
65 7 90.4 05 0
82.6 78.8 83.0
98.3
83.0
99.7 67.8 76.6 83.3 75.6 85.1
83.9 62.4 72.0 76.4 69.4 75.1
92.3
79.3
94.8 97.1 98.8 99.8 98.0 98.6
81.9 81.1 83.3 84.6 82.2 83.5
99.2
Is0
+ 0.077
6.8:1
Motor Method, ABTM D 357-48
40.2 53.0 64.3 56.4 74.0
83.4 83.4
65 6 5 7 0 75 8 0 8 5 MOTOR METHOD OCTANE
70 70 7 5 80 8 5 90 95 RESEARCH METHOD OCTANE
C.R. 1O:l
FUEL
Voriour Bose Stock {Gosotine Blends Above t 10%Ethonal t 25%Ethonol
A----A---0----.----Above
*q/
,
,
,
90
95
100
n
p
70 70
75
80
85
RESEARCH METHOD OCTANE
MOTOR METHOD OCTANE
Figure 2. Comparison of Gasoline and Gasoline-Ethyl Alcohol Borderline Method Road Ratings with Laboratory Ratings The increases of Research and Motor performance numbers of
the same three classes of fuels, either leaded or unleaded in a limited octane range, 70 t o 90 and 65 to 85, respectively, are shown in Figures 7 and 8 as a function of ethyl alcohol in the mixture. As previously stated, present-day commercial gasolines fall between highly cracked fuels and either reference fuels or themsocalled sensitive fuels (diisobutylene-toluene reference fuel blends). This laboratory is engaged in a cooperative study with the U. S. Bureau of Mines, Shale Oil Demonstration Plant, Rifle, Colo., on the possible beneficial effect that alcohol-water injection, or alco-
‘
INDUSTRIAL AND ENGINEERING CHEMISTRY
1100
Vol. 44. No. 5
TABT,E 111. KNOCK RATINGOF ETHYL ALCOHOL BLENDED WITH FIVEBASESTOCK MIXTURES
Fuel, To by Vol .
A" A plus 1 ml. tetraethyllead A plus 3 ml. tetraethyllead A plus 1 0 7 ethyl alcohol A 1 ml. tezraethyllead, plus A' 3 ml tetraethyllead, plus A'plus i 5 % ethyl alcohol A 1 ml. tetraethyllead, plus A: 3 ml. tetraethyllead, plra
10% ethyl alcohol 10% ethyl alcohol 25% ethyl aloohol 25% ethyl alcohol
Bb B plus I ml. tetraethyllead B plus 3 ml. tetraethyllead
]B plus 10% eth 1 alcohol ]B, 1 ml. t e t r a e t b l e a d , plus
10% ethyl alcohol
B 3 ml. tetraethyllead, plus 10% ethyl aloohol ] B ' P ~ U25% S ethyl alcohol B, 1 rnl. tetraethyllead, plus 25% ethyl alcohol B, 3 ml. tetraethyllead, plus 2 5 % ethyl alcohol
Ce C plus 1 ml. tetraethyllead C plus 3 ml. tetraethyllead C plus 107 eth 1 alcohol C 1 ml te$raet&llead plus 10% C' 3 ml' tetraeth llead' plus 10% C'plus 25% ethyralcodol C 1 ml. tetraethyllead, PIUS 25'7 C: 3 ml. tetraethyllead, plus 26%
ethyl alcohol ethyl ahohol ethyl alcohol ethyl alcohol
Dd
U plus 1 ml. tetraethyllead D plus 3 ml. tetraethyllead D plus 10% eth 1 alcohol D 1 ml. tetraetzyllead, plus D' 3 ml tetraethyllead, plus D'plus i 5 % ethyl alcohol D 1 ml. tetraethyllead, pliis u: 3 ml. tetraethyllead, plus
10% ethyl alcohol 10% ethyl alcohol 25% ethyl alcohol 25% ethbl alcohol
336
E plus 1 ml. tetraethyllead
R n l n ~3 ml. tetraethvllead 3 io% ethyl alobhol E 1 ml tetraethyllead, plus 10% ethyl alcohol E: 3 ml: tetraethyllead, plus 10% ethyl alcohol
Laboratory Octane No. Researoh M o G Method Method 81.2 71.8 77.7 88.0 82.6 94.0 78.6 88.5 78.9 94.0 84.3 96.8 80.4 94.1 82.0 96.6 84.8 99.2 80.0 70.4 86.2 76.4 81.3 92.7 75.0 84.6 81 . O 91.1 84.1 96.6 78.7 93.8 81.7 92.3 88.3 98.7 68.0 61.0 76.3 73.0 83.6 78.6 74.3 76.0 91.8 80.0 82.9 94.1 78.0 88.7 93.2 82.4 93.0 85.2 67.3 60.7 69.7 76.4 78.2 86.2 80.1 68.8 83.7 78.9 81.6 91.3 76.7 82.3 81.4 92 . 0 83.4 95.8 54.2 49,s ti3 . 0 65.7 74.0 76.6 55.8 64.8 74.6 76 .O 82.8 80.0 7%. :i 74.1 79.7 78.9 89 7 84.6
Borderline Method, Ford 6, compression ratio 6.8 to 1000 1500 2000 2500 82.8 7 9 . 3 76.3 73.5 88.6 84.6 80.6 75.3 92.9 89.9 85.8 81.6 89.7 85.0 82.5 78.2 93.0 89.0 85.5 80.5 95.0 91.5 87.3 82.7 97.8 89.0 84.0 77.5 98.5 90.8 85.7 79.8 80.8 99.3 92.5 86.8 77.5 7 6 . 3 74.0 70.8 82.0 81.6 74.2 78.3 90.1 8 9 . 0 81.7 85.3 90.5 84.6 77.3 81.7 9 2 . 0 87.5 80.2 84.5 9 4 . 0 91.0 82.0 87.0 96.2 88.0 77.0 83.0 97.7 9 0 . 0 84.8 79.0 98.8 9 3 . 0 82.0 87.0
Road Octane No. Borderline Method Oldsmobile General Motdrs test engine, 1, r.p.m. c o m p r e k o n ratio IO t o I, r.p.m. 3 0 0 0 1000 1500 2000 2500 3000 71.0 .. .. 72.0 ,. 76.3 .. .. .. 74.3 .... 76.5 96.7 96:s 9 4 : 2 96:5 8 ? : 5 77.5 97.5 9 7 . 5 96.5 94.6 9 1 . 5 70.097.5 97.2 9 4 . 0 90.5 88.0 70.0 Is0 + 0 . 1 97.7 96.7 94.0 91.0 71.8 Is0 0.25 98.5 97.5 9 5 . 0 9 2 . 0 69.0 ,... .. .. 71.3 .,.. 77.0 .. 71.4 .... 76.0 93.5 93:O 9215 90:5 8 6 : O 77.2 95.0 9 5 . 5 9 5 . 0 94.0 9 1 . 5 70.096.2 95.0 9 3 . 5 9 1 . 0 8 6 . 5 70.0 98.0 97.0 95.2 9 4 . 0 9 0 . 5 72.3 Is0 0.04 98.5 9 7 . 2 0 5 . 7 9 1 . 0
77:5 83.0 85.0 87.4 91.5 94.5 97.0 98.8
76:5' 79.6 82.4 85.8 89.7 86.8 89.5 92.3
7i:3 82.7 78.0 82.0 86.0 82.3 85,5 87.4
7i:2 77.0 75.0 78.0 81.0 76.5 80.0 82.4
7i:2 76.2 70.0 74.2 77.0 70.070.5 72.0
77:5 82.8 77.5 82.5 87.0 93.8 98.2 99.2
77:s 82.5 75.0 81.0 86.8 85.0 90.0 93.0
76:O 82.0 74.5 79.0 84.6 81.2 85.0 86.8
74:3 7211 79.0 75.0 73.0 71.0 7 7 . 5 75.6 8 0 . 3 76.8 77.3 70,O79.0 71.5 8 2 . 3 74.6
-______-___
..
+
....
..
.. 77:5 70.0 72.5i82.2 82.5 85.0 89.5
..
..
7s:a
74:o
72:5+ 81.2 78.0 84.0 87.0
72:5 78.8 75.0 79.0 81.2
..
.
I
+
.... .).. ....
.... ....
94.0 98.0 Iso 0.03
+
,...
7s:3 71.0 74.5 79.2 82.0 95.0 97.0
..
.... ....
....
87.5 90.0 96.7
....
.. ia:s
.... ...
. . ...
7i:o 76.8 70.072.0 74.5
....
....
96.5
.. ,
.
.
.
,
..
.
.
.,
. . . . . .
..
,.
..
. . . . . .
.
.. .. .. I
..
92:5 9017 8 i : 7 8 7 : O 9 5 . 5 9 4 . 5 9 4 . 0 91.0 9 8 . 0 97.0 Q 5 . 2 9 3 . 0
.. .. .. ,. ..
.,
..
..
..
,.
.. ..
I
,
(
,
88:5 H6:O 9 1 . 0 90.5 96.2 95.2
..
8816
94.0
. .
,
.. ..
I
1
.. .
.
. .
87:6
91 5
..
.. .
I
..
..
89:O 86:O 90.2 8 7 . f 9 4 . 0 91.D
..
. ,
..
.
$ti 7
91 5
..
..
.. .. ..
d6:O 90.0
A = 90% catalytically cracked and 10% polymer.
6 B = 63% catalytically cracked, 7% polymer, and 30% thermally cracked. c
d 6
C = 45% catalytically cracked, 5% polymer, and 50% straight-run.
D = 32% catalytic?lly cracked, 3 % polymer, 30% thermally cracked, and 35% straight-run. E = 22.5% catalytically cracked, 2.5% polymer, and 75% straight-run.
hol in general, may have on shale gasolines with various sulfur contents. I n a preliminary investigation the octane nurnbers of three samples of shale oil gasolines having 0.13, 0.22, aud 0.36% sulfur were determined, The results in Table V show that, in general, t h e addition of alcohol raises the octane number independently of the presence of lead or the amount of sulfur. More detailed investigations are in progress. It may be concluded from the data that the octane blending value of ethyl alcohol in & r i m of performance number is a function of the octane range &s far as investigated (up to approximately 25% ethyl alcohol). The presence of tetraethyllead has, on the average, little effect on the performance number blending value of ethyl alcohol; however, individual results may diverge somewhat. This, how-
TABJ,EIV.
KNOCK RATING O F ALCOHOL R L E N D ~WITH D Two C O M ~ R C I GASOLINBS AL
Fuel Dasaription, % by Vol. Regular gradeb Regular grade plus 1 ml. tetraethyllead Regular grade plus 2 ml. tetraethyllead Regular grade plus 10% ethyl alcohol R e ular grade 1 ml tetraethyllead, &a 10% etLv1 a l c o ~ o l Regular gFade,- 2 ml. tetraethyllead, plus 10% ethyl alcohol Regular grade, 1 ml. tetraethyllead, plus 25% ethyl alcohol . Regular grade 2 ml. tetraethyllead, plus 25% et& alcohol Premium gradec Premium grade plus 1 mi. tetraethyllead Premium grade plus 2 i d . tetraethyllead Premium grade plus 10% ethyl alcohol Premium grade, 1 ml. tetraethyllead, plus 10% ethyl alcohol Premium grade, 2 ml. tetraethyllead. plus 10% ethyl alcohol Premium grade plus 25% ethyl alcohol Premium grade, 1 ml. tetraethyllead, plus 25% ethyl alcohol Premium grade, 2 ml. tetraethyllead, plus 25% ethyl alcohol a b c
Lab. Octane Rating ModiRefied search Motor UnionMethod Method towna 75.0 81.2 77.6 82.3 79.3 .. 84.2 82.0 82 .'7 86 4 81.0
Ford 6 oompression ratio 6.8 to 1, r I Contaihs 1.90 ml. of tetraethyllead. Contains 2.87 ml. of tetraethyllead.
Road Octane No.
IO00 79.0
Borderline Method* 1500 2000 2500 79.0 78.5 78.0
..
..
..
3000 74.0
8k:O
si:o
85:o
si:o
73:5
..
..
88.7
84.2
87.0
84.6
86.0
86.5
82.5
75.0
89.9
85.9
89.0
88.0
90.5
87.5
83.5
78.0
96.5
86.6
95.0
95.3
91.5
87.2
82.0
73.0
97.2 86.2
87.0 81.0
96.0
95.6
92.5
87.5
82.7
73.5
81.:
850
84.5
85.2
8.X-L
81.0
87.2
82.5
..
..
..
..
..
..
88.6 90.9
84.0 82.3
88:5
9O:O
89:5
86:6
82:4
75:O
91.6
83.5
90.5
89.0
91.2
87.9
83.4
75.5
92.6 97.5
85.7 84.8
90.7 95.5
90.0 95.4
91.5 91.5
88.2 86.6
83.5 81.0
76.0 72.5
97.7
86.2
96.1
96.5
92.0
87.5
82.0
73.0
98.4
87.6
97.2
96.8
92.5
88.2
82.6
74.0
INDUSTRIAL AND ENGINEERING CHEMISTRY
May 1952
1101
to 18 for reference fuels. The same blend increases the Motor *0 °' Method performance n u m b e r approximately half as much. 90 A 25% ethyl alcohol blend increases the Research Method performance number from 16 to 80 26 for 65 to 100% cracked stock, 23 to 32 for 50 to 100% straight run, and 28 to 36 for reference ro 70 fuels. The same blend raises a 5 Motor Method p e r f o r m a n c e 2 W number from 2 to 12 for 65 to 5 60 100% cracked stock, 8 t o 17 for 0 50 to 100% straight run, and 10 50 20 for reference fuels. T h e gain in performance 50 number given by commercial grade fuels with a given per cent ethyl alcohol blend may fall any40 where in the range shown for 65 0 1 1 3 4 0 5 10 15 20 25 0 5 IO 15 20 25 T.E.L. M L . / W L . 1 . E . L MLJGAL. * PERCENT BY VOLUME, PERCENT BY VOLUME, to 1OOyo cracked stock and 50 ETHANOL IN BLEND ETHANOL IN BLEND Figure 3. Effect of Adding Tetraethylto 100yostraight run. Figure 4. Variation of Octane Rating lead on the Octane Rating of Various In the particular case investiFuels with Per Cent of Ethyl Alcohol in Fuelgated the presence of sulfur apAlcohol Blends pears to have no significant effect on the octane number increase with alcohol. Table VI gives the average increase in performever, is not true in the case of highly cracked stocks where ance numbers resulting from the alcohol blend. the increase of Motor Method performance number with the addition of 25% ethyl alcohol is less than when no lead is present. ALCOHOL-WATER INJECTION IN AUTOMOTIVE ENGINES The increase in Research Method performance number of ethyl A considerable number of experiments have been made and alcohol blends approaches zero as the Research Method octane results obtained on the alcohol-water injection requirement and value of the fuel itself approaches the Research Method octane consumption data for various types of vehicle operation ( 2 , 7, 11, rating of ethyl alcohol (iso-octane plus 0.33 ml. of tetraethyllead 1 3 , l 7 ) . The amount of injection necessary for knock-free operaper gallon). The best Research Method performance number tion will depend on the nature and octane number of the base increase for all fuel types occurs in the Research Method octane gasoline, the engine, the type of operation, and the composition range of 72 to 92. of the antidetonant mixture; therefore, a compromise must be The increase in Motor Method performance number obtained made in practical operation. by an ethyl alcohol blend approaches aero as the Motor Method Figure 9 shows the full- and part-throttle octane requirement of octane value of the fuel approaches 92, the Motor Method octane rating of ethyl alcohol. The highest Motor Method performance number increase for all fuel 105types occurs in the Motor Method octane range W z below 80. 100The gain in Research Method performance 0 4 number for all fuel types increases as the per5 centage of ethyl alcohol in the blend is increased, p 90as far as investigated, but the relative gain in 2 performance number for a given per cent ethyl m 4 alcohol blend is less for a highly cracked fuel 80than for one predominantly straight run. Reftb erence fuels show the best results. I The Motor Method performance number may m increase with the percentage of ethyl alcohol in $ 70the blend but it may also show little or no gain, z W especially in some commercial gasolines and 2 8 highly cracked fuels. At 3000 r.p.m. Borderline 0 60rating, a 25% ethyl alcohol blend actually results t; in a lower rating than the original fuel for some I fuels in some engines. For any given ethyl alcohol 50blend the performance number gain depends on W 4 0 4 8 12 16 20 24 the type of fuel. Highly cracked stocks show less I PERFORMANCE NUMBER INCREASE gain than straight run and the best gain is obOF FUEkETHANOL BLEND I I I I 401 IO 20 30 40 tained with reference fuels. Figure 6. Variation of PERFORMANCE NUMBER INCREASE OF FUEL-ETHANOL BLEND Motor Method PerformA 10% ethyl alcohol blend,, for instance, proance Number with Fuel Figure 5. Variation of Research Method duces a Research Method performance number Type and Octane Range Performance Number with Fuel Type increase of from 4 to 12 for 65 to 100% cracked in a 25Cj" Ethyl Alcohol and Octane Range in a 250/, Ethyl Alcohol Blend Blend stock, 8 to 14 for 50 to 100% straight run, and 10 MOTOR METHOD
RESEARCH METHOD
RESEARCH (IETHW
100
'Y
MOTOR METHOD
POLYMER
r
5
s
/
__1
1102
INDUSTRIAL AND ENGINEERING CHEMISTRY
28 r a n Oldsmobile 98 with the General Motors Research high compression test engine a t 10 to 1 compression ratio. S u p e r imposed a r e first, the fullthrottle Borderline rating of the base gasoline Commercial Grode used for injecAnd 50-!OO%St Run tion, and second, that of the base 65-IOOX Crcckad gasoline m-ith injection. W i t h 0 4 E I2 16 2 0 2 4 2 8 3 2 3 6 4 0 this base gasoINCREASE IN RESEARCH METHOD PERFORMANCE NUMBER line, knock-free Figure 7. Variation of Research o p e r a t i o n at Method Performance Number Inhigh speeds was crease with Per Cent of Ethyl Alcohol in Blend and with Fuel TyGe a c h i e v e d only For fuels in 70 to 90 o c t a n e range hs Research by retarding the Method initial spark from 5" t o 2.5" before top dead center. However, later tests indicated little or no decrease in general performance. From Figure 9 it would appear that the full-throttle octane rating of the base fuel should satisfy the octane requirement at 4 inches of mercury vacuum at speeds above 2000 r.p.m. ilctually, however, the engine knocked a t 6 inches of vacuum and 2000 r.p.m., indicating that the part-throttle rating of t h a t particular base gasoline is
lower than its full-throttle rating. The amount of injection at various speeds is shown in Figure 10 as a function of manifold vacuum, necessary for knock-free operation of that particular engine. The automatic device which was used gave some overinjection a t 4 inches of mercury manifold vacuum and a t low speeds under fullthrottle. The cutoff for all speeds was sharp betyeen 6 and 8 inches. Except for a peak a t 1500 r.p.m., injection decreased with engine speed. Alcohol-R-ater consumption tests for t,he same engine-vehicle noted previously, recombination are given in Table VII. tarding the spark by 2.5" from its standard p o s i t i o n did not affeot car performance noticeably. Each set of data was obtained on a 150mile test c o u r s e , which included city and country driving a t a n over-all a v e r a g e speed of 65-100% Crocked around 50 miles per hour. T h e t o t a l Commerciol Grcde m i l e a g e for each run was a p p r o x i mately 1000 miles. T h e lower rear axle 0 4 8 i2 16 2 0 24 INCREASE IN MOTOR METHOD PERFORMANCE N U M B E R ratio increased both Figure 8. Variation of Motor the miles-perMethod Performance Number Ingallon-of-gasoline crease with Per Cent of Ethyl Alcoreading and the hol in Blend and with Fuel Type alcohol-water mixFor fuels in 60 to 85 octane range b y Motor Method ture consumption;
TABLEv.
SHALE
Vol. 44, No. 5
GASOLIXE OCT.4NE
XUMBERS
Sulfur, Yc by Wt. 0 13 0.22 0 3 6 R A I ~3 1 ~ 1 5 R M m i R ~ I R?M Shale gasoline without ethyl alcohol 64.0 Shale gasoline plus 10% ethyl alcohol 72.4 Shale gasoline plus 2 5 % ethyl alcohol 84.4 Shale gasoline plus 1 ml. tetra66.8 ethyllead/gal. Shale asoline 1 ml. tetraethyl!ead$gal., p l k 10% ethyl alcohol 76.0 Shale gasoline, 1 ml. tetraethyllead/gal., plua 2 5 % ethyl alcohnl 85 6 gasoline, plus 3 ml. tetraethyllead/gal. 76.3 Shale gasoline, 3 ml. tetraethyl!ea.d/gal., plus 10% ethyl alco84.0 hol Shale gasoline, 3 ml. tetraethyllead/gal., plus 2 5 % ethyl alco93.6 hol
sLZ
a
6 5 . 0 60 0
59.5
66.0 60.0
65.5
72.4
68.0 72.8 65.5 74.0 84.6
73.9
84 5
63.5
7 0 . 5 65.1
67.5
78 3
73.1
72.0 65.5
70.7 79.6
69.7
76.0 88.1
76.6
88.2
76.3
70.7 78.7
69.2
76.6
70.6
72 6
85.1
72.8
85.6
74.9
78.2
93.2
80.3 93.2
80 6
R 3 I and A I M are Reseaich and Motor RIethod octane numbers respec-
tl'e'"
TABLET'I.
~ ~ V E R A GINCREASE E I N PERFOPAIAVCE NUVBERS AS A RESULT OF ETHYL ALCOHOL BLEXD
10% Ethyl .4lcohol
Fuel Type Prior to Ethyl Alcohol Blend
Rhla
RIAIb
2-57, Ethyl .Ilcohol
RM
R33I
11
6
31
14
12
6
30
10
9
4
24
10
9
4
25
7
7
7
22
14
B 1 ~ n o d o s k " ~ 3 5 ~ ~ / 0 ~ ~ . 0 ~ t ~ t r s , " ~ ~ ~ 6~ ~ ~ ~ 25~
13
ence fuels primary and referLeaded (1 to 4 m1.1 primary and secondary reference iuels Commercial fuels (0 to 2 ml./gal. tetraethyllead) Abol,e commercialfuels with added lead
Blends (2 t o having 4 ml./gal. 5o to tetraethyllead) straight-run stock, unleaded
Bl;;$k,hu&n';2de:5 to 100% cracked 8 Blends having 65 t o 100% cracked stock, with mi./gai. a R M = Research Method octane numbers. b 3Ihl = Motor h'lethod octane numbers.
5
21
9
4
17
3
-
however, the latter was more than offset bj, the former. Increased consumption u-as caused by the greater low speedinjection requirements. Injection alone will cause a lowering in gasoline consuniption without adjustment of the carburetor. This has been observed repeatedly in a number of test,s here and a t other plac-es. Conclusions that may be drawn froni these data are that it is possible to use a good grade premium gasoline with alcoholwater injection in a high compression ratio engine having an octane requirement, in the range of 95 to 100, provided the high speed rating of the gasoline is close to its octane requirement a t high speeds, so that. only a small octane gain is required. -Rood
Octane Requlrement W l t h initial Sp. Adv. Z?,'B.T.C. Throllle Borderline Rating
-.-Full
Of Premium Grade Goroline,93.5/85
LL
3
3
90
K
w
ENGINE R.P.M
Figure 9. Road Octane Requirement ws. Speed and Throttle Setting for a 10 to 1 Compression,Ratio Engine 50-50 ethyl'alcohol-water mixture used
,
May 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY -1000
RPM
--3000
RPM
MANIFOLD VACUUM, IN.
Figure 10.
HG.
Injection Ratio as
a Function of Speed and Mani-
fold Vacuum
Automatic injector used with General Motors C o . high compression ratio test engine 30-50 ethyl alcohol-water mixture used
w
3
P N 3 Performance Number
I
0
1103
I
20 40 60 80 100 PERCENT WATER IN ETHANOL-WATER MIXTURE
Figure 11. Variation of Injection Ratio Required for Trace Knock with Per Cent of Water for Standard and High Compression Ratio Engines at Low Speed, and for Low and High Speed for the High Compression Ratio Engine
r
0
2
4
6
8 10 I2 14 OCTANE INCREASE
I6
18
20
2
Premium gasoline used in high compression ratio engine road rated as 941/e for 1000 r.p.m. and 921/z for 3000 r.p.m.
Figure 12. Variation of Octane Gain Achieved by Injection with Octane Range of Base Fuel
5
5 40-
For a v e r a g e driving with an a u t o m a t i c injector which follows closely the injection requirements for k n o ck-free operation, the o v e r - a l l cons u m p t i o n of a1 c o h o l - w a t er mixture is low 5 0 4 8 12 16 20 24 28 32 36 40 and, therefore, INCREASE IN PERFORMANCE NUMBER AT 1000 R P M quite economiFigure 13. Variation of Performance cal. Number Gain Achieved by Injection a t A 50-50 ethyl Low Speed with Base Fuel Type a1co h o I-w a ter mixture appears to be the besL composition in the high octane range, where both high speed and low speed octane gain are required. The octane requirement W level of 100f a t low speeds and 95 at high speeds is near the limit a t which alcoholwater injection will give a Z L 016 3 0 s a t i s f a c t o r y octane gain. However, the octane reResearch Method Octane
# ' K ,, 3
=Lzc
&
,2
,
,
eo
,
24
24
2.
quirements of all engines can be reduced through reasonable spark adjustment and the incorporation of various design features (12). Injection alone may lower gasoline consumption and add t o the economy of operation. EFFECT OF MIXTURE COMPOSITION
Figure 11shows the injection ratio as a function of the percentage of water in the ethyl alcohol-water mixture a t two speeds. At IO00 r.p.m. the injection ratio increases as the percentage of water is increased, while at 3000 r.p.m. the injection ratio decreases until about a 50-50 mixture is reached. At greater speeds the ratio remains fairly constant. This is in line with the previously discussed fact t h a t as the octane requirement of the engine a t high speeds approaches the Motor Method octane number of ethyl alcohol, the performance gain approaches zero. At lower compression ratios both the low and high speed curves slope upward. The importance of the effect of performance number increase on injection ratio is shown clearly by the two curves for a 6.8 to 1 compression ratio engine. While a performance number increase of 15 required only about 6 % with a 50-50 mixture, the injection ratio is increased t o 26% for a gain of 23 performance numbers. I n other words, the injection ratio was raised fourfold for an approximately 50% gain in performance numbers. For high performance number gain a t both compression ratios in the low speed range, a high alcohol content will reduce significantly the injection ratio required. The octane increase as a function of injection ratio for two
TABLE VII. ROADTESTRESULTS WITH ALCOHOL-WATER INJECTION IX A 10 TO 1 COMPRESSION RATIOAUTOMOTIVEENGINE
INCREASE IN PERFORMANCE NUMBER AT 2500 R E M .
Figure 14. Variation of Performance Number Gain Achieved by Injection at High Speed-with Base Fuel 'l'ype Motor method octane range of fuels, 80 to 85. Fuels road rated from 85 94 at 2500 r.o.m. 85-15 . . ethyl alcoho1lvate;ratio 10-1 compression ratio 2500 r.p.m. Peak octane requirement, 95 to 97
Acceleration Time, Octane Rating ReSpeo. search Motor Fuel Method Method Gravity Iso-octane 100.5 100 0.69 85.0 0.73 Premium 93 Iso-Ootane loo loo 0.69 Premium 93.5 85.0 0.73 a Before top dead center.
Init. Spark Advancea 5' 2i/so 5 2 */so
Sea..
from 0 to 70 M.p.h. 15.0 14.5 14.7 15.0
Av. Miles/ Gal Gas:-
line, over Test Course 17.8 19.0 18.9 20.1
Av. Miles/Gal. AlcoholWater Mixture, over Test Course No injeotion 1900 No inieotion 1255
Over-all Ratio AlcoholWater Consumed/ Gasoline,
%
1'.b 1'.6
Rear Axle Ratio 3 . 6 3 to 3.63 to 3.23 to 3.23to
1 1 1
1
1104
INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
ranges of reference fuels is shown in Figure 12. The curves are not linear and large octane gains have to be obtained by disproportionate amounts of injection. The effect of gasoline composition is demonstrated in Figures 13 and 14 in which the increase of performance number is plotted against injection ratio a t 1000 and 2500 r.p.m., respectively. As stated previously, present commercial gasolines are less responsive to alcohol-water injection than standard and the so-called sensitive reference fuels.
Vol. 44, No.
5;
LITERATURE C I T E D
(1) Bogen, J. S., and Nichols, R. RI., IXD.ENG.CHEM.,41, 2629
(1949). (2) Colwell, A. T., paper presented a t 1948 Soc. Automotive Engrs.
National Tractor and Diesel Engine Meeting, Nilaaukoc, Wis., Sept. 9, 1948. 13) “CRC Handbook.” compiled by the Coordinating - Research Council, Inc., New York, 1946. (4) Heron, S. D., and Beatty, H. A., J . Aeronaut. Sciences, 5 , 463
.
11938). ---,
For performance number gains of 5 to 10 with present-day engines and where the base fuel used with injection is in the octane range below 85, a 50-50 alcohol-water mixture appears to be as good as a n 85 to 100% ethyl alcohol mixture and more economical. For very small octane gains 100% water may be used. For performance number gains of 10 t o 30 with present-day engines, the alcohol content of the mixture should be between 50 to 100% t o prevent a n excessive injection requirement. In many case6 a compromise may be made. For the General Motors Research high compression test engine a t 10 t o 1, having octane requirements of 100 or more at low speeds and of about 95 a t high speeds and using a base fuel of 90 to 95 (Research octane number), a 50-50 alcohol-water mixture appears t o be a good compromise. Under these conditions the performance number gain is 20 to 30 at low speeds and 5 to 10 a t high speeds. I n previous work (7, I S ) it was shown that methanol is for all practical purposes equivalent t o ethyl alcohol in antidetonant mixtures, but that isopropyl alcohol alone is somexThat less efficient.
(5) Hershey, D. S., Eberhardt, J. E., and Hottel, H. C., S.A.E. Journal, 39, 409T (1936). (6) Hottel, H. C., Williams, G. C., and Satterfield, C. N., “Thermodynamic Charts for Combustion Processes,” Pt. I and 11. New York. John Wiley & Sons, Inc., 1949. ( 7 ) Porter, J . C., Gilbert, M. M., Lykins, 1%. A., and Wiebe, Richard, Agri. Eng., 31, 71 (1950). (8) Porter, J. C., Roth, W. B., and ?Tiebe, Richard, Aztlomotite I n d s . , 98, No.8, 34 (1948). (9) Potter, R. I., SAE preprint, Soc. Automotive Engrs. bleeting, June 1948. (10) Rowe. M. R.. and Ladd. G. T., S.A.E. Journal, 54, 26T (1946). (11) Smith, J. T., Shaw, G. N., Van Hartesveldt, C. H., and Kilgore, W.E., SAE preprint, SOC.Automotive Engrs. meeting, Dec. 13, 1948. (12) Taub, Alex., Automotzve I n d s , 101, No. 1, 28; No. 2, 36; S o . 3. 34 (1949). (13) Van Hartesveldt, C. H., S.A.E. Quart. Trans., 3,277 (1949). (14) Veal, C. B.. S.A.E. Journal, 35, 131‘ (1934). (15) Veal, C. B., Best, H. W., Campbell, J. AT., and Holaday, 11’. AI., Ibid.. 32. 105T (1933). (16) Wiebe,’Richard, and Nowakowska. Janina, U. 8. Dept. Agr., Bibliography Bull. 10 (1949). (17) Wiebe, Richard, and Porter, J. C., U. 8.Dept. Agr., AZC 240 (1949). (18) Wiebe, Richard, Schults, J. F., and Porter, J. C., IND.ENG. CHEM.,34, 575 (1942); 36, 672 (1944).
The assistance of C. F. Elder, M. RI. Gilbert, H. A. Lykins, A. P. McCloud, and C. R . Martin in obtaining the data is acknowledged.
RECEIVED for review April 2 6 , 1951. ACCEPTED December 4,1951. Presented before the Division of Petroleum Chemistry at the 119th Meeting of t h e Axmuc.m CHEMICAL SOCIETY, Cleveland, Ohio. Report of a study made under the Research and Marketing Act of 1946
SUMMARY
ACKNOWLEDGMEYT
Pigment Colors for Vinvl C d
GEORGE WORRZALD AND W. F. SPENGEMAN E. I. d u Pont de Nemours & Co., Inc., Newark, N. J .
ITH the commercial introduction of plasticized vinyl chloride polymers about a decade ago, problemsin coloring arose which were somewhat different from those faced by formulators of paint, printing ink, and related polymeric systems wherein pigment colors are widely used. The choice of color for the polymeric systems was determined largely by considerations of end use-Le., lightfastness, chemical resistance, etc. Rigid, i.e., unplasticized vinyl chloride polymers, are also included in this category since the coloring problems are relatively simple, both dyes and pigments being used depending on the ultimate use. I n vinyl systems, however, factors in addition to end use exert effects considerably greater and different from those observed in the other common polymers. Specifically these factors were shown t o be related to the chemical and physical reactions between the colorant, plasticizers, and stabilizers used, and t o the chemical effect of the colorant on the stability of the vinyl chloride. When these factors were thoroughly recognized, i t became apparent that the chemical and physical nature of the colors used would have t o be scrutinized more closely than they were for most
uses. Oil-soluble dyes were shown to be much too soluble and t o cause excessive crocking and migration. Accordingly, essentially nothing but pigment colors are used today. Since chemical and physical factors are so important in pigmenting vinyl polymers, i t is the purpose of this discussion to present a simplified classification of pigment colors from the cfiemical viewpoint and to comment on the suitability of the various types of colors for pigmenting vinyl polymers. The term “vinyl polymer” or “vinyl plastic” refers in this discussion to plasticized vinyl chloride polymers and copolymers as represented by a typical formula containing 100 parts of polyvinyl chloride or copolymer resin, 30 to 60 parts of plasticizer (primary and secondary plus a diluent), 1 t o 5 parts of stabilizer (light and heat), and 1 t o 5 parts of lubricant. For purposes of review, Table I shows a simplified classification of synthetic pigment colors broken down into two major groups, the organic and inorganic. Since naturally occurring pigments, such as the ochres and umbers, are seldom used in this type of plastic, they are not considered in the classification.
