Technical Paper 214
тр
647.2
028
DEPARTMENT OF THE INTERIOR
· FRANKLIN K. LANE, SECRETARY
BUREAU OF MINES
VAN. H. MANNING, DIRECTOR
Petroleum Technology 52
A 559364
MOTOR GASOLINE
PROPERTIES, LABORATORY METHODS
OF TESTING, AND PRACTICAL
SPECIFICATIONS
BY
E. W. DEAN

Byron
TMENT
OF
THE
WASHINGTON
GOVERNMENT PRINTING OFFICE
1919
не

The Bureau of Mines, in carrying out one of the provisions of its organic
act-to disseminate information concerning investigations made-prints a
limited free edition of each of its publications.
When this edition is exhausted, copies may be obtained at cost price only
through the Superintendent of Documents, Government Printing Office, Wash-
ington, D. C.
The Superintendent of Documents is not an official of the Bureau of Mines.
His is an entirely separate office and he should be addressed:
SUPERINTENDENT OF DOCUMENTS,
Government Printing Office,
Washington, D. C.
The general law under which publications are distributed prohibits the giv-
ing of more than one copy of a publication to one person. The price of this pub-
lication is 5 cents.
First edition. February, 1919.
2
Chemie af Lib.
1
from a bouts
17- ३०
Foreword
Introduction___.
CONTENTS.
Acknowledgments..
Need of gasoline specifications.
General properties of satisfactory gasoline_-.
Straight" refinery gasoline_.
Types of gasoline marketed and their general properties.
Blended casing-head gasoline_.
Cracked or synthetic gasoline.
Properties of gasoline and methods of testing..
Color
Odor
Water, sediment, and other foreign matter
Acidity
Calorific or heating value___
Content of aromatic hydrocarbons-benzene, toluene, and others.
Unsaturated hydrocarbons
Specific gravity.
Volatility
Distillation methods
Review of the gasoline situation___
General considerations in preparing gasoline specifications.
Limits and requirements of gasoline specifications__
Proposed specifications for gasoline
Discussion_.
Color
Acidity
Discussion_.
Volatility
Discussion of temperature limits__
Distillation method and apparatus_.
Flask
Condenser
Thermometer.
Specifications for gasoline distillation thermometer__
Source of heat in gasoline distillation__.
Procedure and details of manipulation in conducting distillations_.
Discussion of details of procedure---
Additional analytical methods employed in the testing of gasoline__
The "doctor" test..
Corrosion and gumming test.
Unsaturation test_
Gravity separation
Centrifugal separation
Page.
5
6
6
7
7
8
∞ ∞
8
9
9
9
10
10
10
10
11
12
12
14
14
15
15
17
17
17
17
17
18
18
18
19
20
20
21
21
7 2 2 * * ***&&.
22
23
24
24
25
25
26
26
3
4
CONTENTS.
Vapor pressure_
Apparatus__.
Procedure-
Forms for recording the results of gasoline analysis..
Centigrade-Fahrenheit temperature transformation table_
Publications on petroleum technology
TABLE.
Table 1. Degrees centigrade to degrees Fahrenheit__.
ILLUSTRATIONS.
1
I
Page.
26
26
27
27
29
31
30
Figure 1. Apparatus used by the Bureau of Mines for distillation test of
gasoline__
2. Graphic chart for recording results of gasoline analysis____.
CHEMICAL
LIBRARY
TP
692.2
D28
1919
19
29
228
MOTOR GASOLINE; PROPERTIES, LABORATORY METHODS OF
TESTING, AND PRACTICAL SPECIFICATIONS.
By E. W. DEAN.
FOREWORD.
This report is issued as a revised edition of Technical Paper 166,
on the properties and testing of gasoline. Discussion that has lost
its significance since the date of issue of Technical Paper 166 has
been omitted, and much information has been added that has become
of recent importance.
With conditions in the oil refining and marketing industries even
more unsettled than they were at the time of issue of Technical
Paper 166, anything approximating a last word on the subject
treated is impossible. But because of the need of keeping the public
in touch with this important and rapidly developing technical field.
the Bureau of Mines issues this report.
INTRODUCTION.
One of the most desirable conditions to be attained in the develop-
ment of technical or commercial undertakings is that producers and
users shall be able to determine the relative desirability of commodi-
ties on the basis of simple and accurate tests. Up to a recent date
such a condition has not been reached in regard to gasoline and it
was believed that satisfactory specifications, based on laboratory
tests, could not be written for commercial transactions in this com-
modity. Claims were frequently made that actual use constituted
the only adequate test for the value of gasoline.
It is now definitely established that the most unreliable test in
vogue for gasoline is that of the average user who "tries it out" in
his car. Engine tests, if conducted in the laboratory in connection
with power measurements, are still the last word in determining the
utility of motor fuel, but the internal-combustion motor is so com-
plex a mechanism that it can not be made to serve as an analytical
instrument except when handled by experts. Properly interpreted
results of an analysis in the chemical laboratory give more reliable
5
6
MOTOR GASOLINE.
information concerning the utility of a grade of gasoline than any-
thing less than the most elaborately conducted engine-dynamometer
tests, or the collective experience of a large number of users.
In the course of the past two or three years rational methods for
analyzing and grading gasoline have come into vogue. Published
descriptions are not, however, readily available and in addition many
of the methods, though based on sound theoretical principles, have
not been developed to an optimum of simplicity and reliability.
The object of the present paper is to furnish information regarding
the desirable properties of gasoline and the best methods of testing it.
Suggestions are offered with regard to rational specifications and
the interpretation to be placed upon the requirements that may be
adopted.
ACKNOWLEDGMENTS.
The bureau began its study of gasoline specifications at the sug-
gestion of W. A. Williams, formerly chief petroleum technologist
of the bureau. Much credit is due Mr. Williams and his successor,
Chester Naramore, for assistance and advice in preparing this report.
To Van. H. Manning, director of the bureau, who has shown par-
ticular interest in the problem, credit is due for guidance in assem-
bling a large part of the material presented.
W. A. Jacobs, H. H. Hill, and C. R. Bopp, of the petroleum divi-
sion of the bureau, collected and analyzed samples of gasoline,
thereby obtaining information of utmost importance in connection
with the discussion and recommendations of this report.
Many of the tests and analytical methods described are based on
the experimental work of chemists and petroleum technologists who
have been kind enough to cooperate with the bureau in furnishing
information. Acknowledgment of credit due these men is made in
connection with descriptions of the tests.
NEED OF GASOLINE SPECIFICATIONS.
The bureau was originally asked to prepare specifications for
Government purchases of several grades of gasoline and naphtha,
and to guide State and local legislative bodies that proposed to for-
mulate regulations for controlling the quality of gasoline. More
lately the bureau has assisted in preparing specifications for the pur-
chase of gasoline for military purposes, particularly for the Aviation
Service.
GENERAL PROPERTIES OF SATISFACTORY GASOLINE.
+2
The fundamental principle upon which gasoline tests and specifi-
cations must be based is that quality is not inherent but is determined
by the service required. For instance, gasoline that is entirely satis-
TYPES OF GASOLINE MARKETED AND GENERAL PROPERTIES.
7
factory in present-day cars or trucks might have been almost useless
in the cars of several years ago and would not serve in airplane
motors at all. Hence a discussion of the desirable properties of
gasoline must be confined to general statements, and then if re-
duced to specifications must take into account the conditions of use.
The essentially desirable properties of gasoline may be summarized
briefly as follows:
1. The gasoline should not contain too large a percentage of highly
volatile products, which tend to cause large evaporation losses and
excessive danger in handling and storage, but should have enough
volatile constituents to permit starting an engine under reasonably
unfavorable conditions, without preheating.
2. The gasoline should not contain any considerable percentages
of heavy or nonvolatile constituents, which after atomization into
the engine cylinders can not be completely vaporized and burned.
3. The gasoline should not contain material that after combustion
leaves a residue that collects in the motor.
1
4. The gasoline should be free from substances that attack metal,
either before or after combustion. Unremoved acid (used in refin-
ing) falls under this head.
5. Neither the gasoline nor its products of combustion should
have a strong or markedly disagreeable odor, as this is objectionable
to users of automobiles.
6. The gasoline should be free from noncombustible material such
as water and sediment.
These stated requirements are simple in principle and are almost
axiomatic. The chief problem is to fix limits, defined by actual
tests, that will satisfy the desirable conditions.
TYPES OF GASOLINE MARKETED AND THEIR GENERAL PROP-
ERTIES.
There are at present on the market types of gasoline produced by
several general methods. These may be clasified as follows:
1. "Straight refinery" gasoline.
2. Blended "casing-head" gasoline.
3. "Cracked" and blended gasolines.
66
""
STRAIGHT REFINERY GASOLINE.
“Straight” refinery gasolines are produced by methods that vary
somewhat in different parts of the country, but in general are simi-
lar. Crude oil is distilled in a fire still until the gravity of the con-
densed product reaches some predetermined mark. The distillate,
so-called crude naphtha or benzine, is acid refined, neutralized,
washed and steam distilled. Several products of different ranges of
8
MOTOR GASOLINE.
volatility may be produced from the crude naphtha, or the steam
distillation may separate the gasoline from the less volatile "bot-
toms" that go into the kerosene or burning-oil stock.
Straight refinery gasolines are generally characterized by a low
content of “unsaturated "a and aromatic hydrocarbons and by a dis-
tillation curve of characteristic form, free from marked irregulari-
ties. The distillation curve of a typical straight refinery motor
gasoline appears later in this paper on Form 2 (see page 29), the
sheet used by the bureau for keeping graphic records of distillation
analyses of gasoline.
BLENDED CASING-HEAD GASOLINE.
During the past few years so-called casing-head gasoline, obtained
from natural gas by compression or absorption processes, has come
on the market. "Straight" casing-head gasoline, especially that
produced by the compression process, is usually too volatile for
general use and, before being marketed, is blended with enough
heavy naphtha to produce a mixture that can be used safely as
motor fuel. In general, blended casing-head gasoline is charac-
terized by a volatility range that shows a considerable percentage
of constituents of relatively low boiling point, and a high "end
point." The characteristic curve of a blended casing-head gaso-
line appears on Form 2, to which reference has already been made.
Frequently, however, the blending is done in a manner difficult to
detect; the natural gas gasoline is used in moderately small pro-
portion with "heavy" straight refinery naphtha in order to make a
product with a desirable percentage of volatile constituents.
As regards chemical properties, blended casing-head gasoline seems
to be identical with straight refinery products of the same distillation
range, provided the comparison is limited to derivatives of the same
or similar producing fields. Characteristic physical properties of
these gasolines are due wholly to the details of blending.
CRACKED OR SYNTHETIC GASOLINE.
"Cracked" or synthetic gasoline is an important factor in the
present market supply of motor fuel and is being produced in large
quantities. It is generally sold in the form of blends with varying
proportions of straight refinery and casing-head gasoline.
Cracked gasolines are similar to straight refinery products in some
physical and chemical properties, but differ in the matter of contain-
a The term unsaturated is generally understood to include olefins and poly-olefins.
The general chemical formula for the olefin series of hydrocarbons is CnH2n. Aromatic
hydrocarbons occurring in gasoline generally fall in the benzene series, having the general
chemical formula CnH2n-0.
PROPERTIES OF GASOLINE AND METHODS OF TESTING.
9
ing varying proportions of unsaturated hydrocarbons." The util-
ity of these constituents has not yet been completely determined. It
appears that they have balanced advantages and disadvantages, and
it is not as yet safe to predict the degree of satisfaction with which
cracked products of relatively high "degree of unsaturation" can be
used in general service. Thus far, however, these products have been
marketed in the form of blends that are perfectly satisfactory and are
generally used without knowledge that they contain cracked gasoline.
PROPERTIES OF GASOLINE AND METHODS OF TESTING.
Before a system of analysis and specifications is outlined it seems
desirable to discuss the individual properties that might be con-
sidered important and to describe analytical methods. This paper is
not intended as a complete review of gasoline analysis, and those
properties that are considered of minor practical importance are not
discussed in detail.
COLOR.
Color is of some importance because it serves as an index of other
qualities. Properly refined gasolines are "water white," and hence
it is often desirable to include a color requirement in specifications
for gasoline. It does not, however, seem necessary to employ a test.
involving any sort of a tintometer, as the rough-and-ready method of
looking through the bottom of a 4-ounce sample bottle or 100 c. c.
graduate is adequate.
ODOR.
Gasoline should be free from a rank or disagreeable odor, as such
odor causes discomfort to users, especially if it has a tendency to
cling to clothing. Of course, one can not fix a definite standard of
quality and strength for odor. The older requirements demanded
the sweet, pleasant odor characteristic of "high-test" uncracked
distillates. With the present necessity of using cracked gasoline this
requirement has become impossible and the requirement of odor must
be omitted or left rather indefinite.
a Aromatic hydrocarbons also occur in smaller degree in cracked gasoline, but for rea-
sons involving economy in production the yield of these hydrocarbons is generally mini-
mized.
Highly unsaturated cracked gasoline shows a loss through treatment with an excess
of cold concentrated sulphuric acid which in some cases runs as high as 40 per cent.
The blends usually marketed are, however, less than 8 per cent " unsaturated.'
• The oil industry commonly employs a cylindrical 4-ounce bottle of the following ap-
proximate outside dimensions: Height of body 5 inches, diameter of body 13 inches,
height of neck inch, diameter of neck 3 inch.
97556°-19- -2
10
MOTOR GASOLINE.
WATER, SEDIMENT, AND OTHER FOREIGN MATTER.
Gasoline should obviously be free from water and other foreign
matter. Water is seldom present in gasoline and is always easy to
detect, as the two liquids are mutually insoluble. Sediment is equally
easy to detect on account of the transparency of gasoline.
ACIDITY.
Obviously gasoline should not contain any of the acid used during
the refining process. Market products rarely fail to meet this re-
quirement, which is so important that a test should always be made.
A simple and effective method of detecting acidity is to shake the
residue in the Engler flask, after an analytical distillation, with a
little distilled water, and then to test this water extract with a suita-
ble indicator, such as litmus, methyl orange, or phenolphthalein.
Shaking the original sample with water does not serve to detect acid
that is chemically combined with the gasoline, and this test, although
recommended in Techincal Paper 166, seems to be practically useless.
CALORIFIC OR HEATING VALUE.
The value of motor fuel is a function of its heating value or B. t. u.
value. The differences in heating value among varieties of gaso-
line are relatively small, and this property is, therefore, not im-
portant enough to merit determination in the routine testing of gas-
oline. Some recent experiments of the Bureau of Mines indicated
that a straight refinery gasoline, with a gravity of 74° B., was
about 1.3 per cent higher in heating value that a cracked gasoline,
with a gravity of 58° B., on the basis of weight and about 7 per cent
lower on the basis of volume. Seemingly the heavier and less volatile
gasolines are actually superior to the high-test light products as re-
gards potential power production per gallon. This assumption, of
course, implies equal efficiency in utilization.
CONTENT OF AROMATIC HYDROCARBONS-BENZENE, TOLUENE, AND OTHERS.
The desirability of aromatic hydrocarbons as motor fuel is a ques-
tion that is already receiving attention. The commercial production
of sufficient toluene to meet the needs of the explosives industry has
yielded an excess of the benzene and solvent naphtha fractions of
light oil and new methods of utilizing these products are being
sought. The total available quantity of these aromatic hydrocarbons
is small in relation to the country's production of gasoline, but it is
a Rittman, W. F., Jacobs, W. A., and Dean, E. W., Physical and chemical properties of
gasolines sold throughout the United States during the calendar year 1915: Tech. Paper
163, Bureau of Mines, 1916, 45 pp. Refer to Table 7, p. 18.
PROPERTIES OF GASOLINE AND METHODS OF TESTING.
11
important, especially in localities where coal is coked in by-product
ovens.
The utility of aromatic hydrocarbons as motor fuel has already
been studied to some extent. On the basis of present evidence, these
products, although chemically different from petroleum hydrocar-
bons, appear to have properties that give certain advantages in utili-
zation. This problem merits discussion beyond the scope of the
present paper; however, the evidence at hand indicates that if aro-
matic hydrocarbons appear in the American market as motor fuel
in the future, users will be benefited.
The percentage of aromatic hydrocarbons permissible in gasoline
for use in the average automobile motor may be necessarily limited
to some maximum that has been proven desirable by experience. The
relatively high freezing point of pure benzene (5.5° C. or 42° F.)
is one factor that may necessitate such a limitation, which can prob-
ably be effected most simply by a gravity requirement. Aromatic
hydrocarbons-benzene, toluene, and the others have specific gravi-
ties of about 0.87 to 0.88 (29° to 30° B.) and distill at the same tem-
peratures as petroleum hydrocarbons having specific gravities be-
tween 0.70 and 0.76 (54° to 70° B.). Therefore, an approximate
idea of the percentage of aromatics in a mixture can be obtained
through the relation between figures for distillation range and spe-
cific gravity.
UNSATURATED HYDROCARBONS.
Another matter that has not been worked out completely is the
effect of unsaturated hydrocarbons on the properties of gasoline.
As already stated, there is conclusive evidence showing that gasolines
containing moderate percentages of unsaturated hydrocarbons can
be used with entire satisfaction, but it has not yet been definitely
established that the presence of unlimited proportions of these con-
stituents causes no disadvantage.
In view of the present market conditions it does not seem desirable
to emphasize any requirements that may interfere with the develop-
ment of cracking processes, as this now seems to offer the greatest
possibility of conserving the country's petroleum resources.
The bureau has recently published as Technical Paper 183 a the
results of a study of the comparative advantages of various analytical
methods employed for determining "degree of unsaturation." This
study has shown that the acid-heat test largely used by refiners is
little better than qualitative and that determinations of iodine absorp-
ion by the Hanus method, though accurate and fairly rapid, requires
a fair degree of manipulative skill on the part of the operator. The
a Dean, E. W., and Hill, H. H., Determination of unsaturated hydrocarbons in gasoline:
Tech. Paper 181. Bureau of Mines, 1917, 25 pp.
12
MOTOR GASOLINE.
measurement of the percentage absorbed by concentrated sulphuric
acid seems on the whole the most practical method of ascertaining the
degree of unsaturation of a gasoline, provided the details of this test
are properly conducted. It must, however, be understood that this
percentage value is not the actual olefin content of the gasoline."
SPECIFIC GRAVITY.
Specific gravity is in itself of very slight significance in determin-
ing the properties of gasoline, except as noted in the discussion of
mixtures containing aromatic hydrocarbons. Gravity may serve as
an index of other properties, particularly volatility, if knowledge is
at hand regarding the source and method of production of a sample
of gasoline.
Gasolines of equivalent volatility from the Pennsylvania and Cali-
fornia fields may have gravities differing as much as 8° Baumé. Fig-
ures indicating this fact appear in Technical Paper 163 of the
Bureau of Mines. In addition gravity measurements do not differen-
tiate straight refinery and blended casing-head gasolines, which may
vary widely in actual composition.
The determination of gravity has been, and probably always will
be one of the most useful tests that the refiner employs, but it is of
little value to the analyst who does not possess enough additional in-
formation to make proper interpretation of gravity results.
Methods of determining gravity are too well known to need dis-
cussion. The type of instrument chosen may be a hydrometer, a dis-
placement balance (such as the Westphal), or a suitable pycnometer.
Of these instruments the hydrometer is perhaps most convenient, the
pycnometer least convenient. The accuracy in determination should
be within 0.1 to 0.2 per cent. The oil industry expresses gravity as
the ratio of the densities of oil and water at the temperature of 60° F.
In some laboratories the accepted practice is to use the temperature
of 15° C. (59° F.) instead of 60° F. The discrepancy thus introduced
is, however, generally less than the experimental error in measure-
ment.
VOLATILITY.
Volatility is the basic property that determines the grade and use-
fulness of gasoline. Unfortunately, it is a complex property, the
grade and usefulness of which can not be stated in a few words,
as different ranges of volatility are desirable for different conditions.
a Brooks, B. T., and Humphrey, Irwin, The action of concentrated sulphuric acid on
olefins, with particular reference to the refining of petroleum distillates: Jour. Am.
Chem. Soc., vol. 40, May, 1918, pp. 822-856.
Rittman, W. F., Jacobs, W. A., and Dean, E. W., Physical and chemical properties of
gasolines sold throughout the United States during the calendar year 1915: Tech. Paper
163, Bureau of Mines, 1916, p. 32.
PROPERTIES OF GASOLINE AND METHODS OF TESTING.
13
of use and these are subject to wide variation. Thus it may be noted
that the same type of gasoline is not equally desirable for airplane
and truck motors, and that the type of motor fuel that would be
most suitable for use in the Canal Zone might not give good results
in Alaska. Hence, it is easily seen that a discussion of the desirable
properties of volatility must necessarily be confined to generalities.
There are, however, certain simple basic principles that merit brief
consideration.
In the first place, it is desirable to use as cheap a gasoline as can
be made to yield satisfactory results. The men who have to pay for
maintaining cars in service need no argument in support of this
statement, and it is equally sound from another and broader point
of view. In the interest of conservation it is desirable to draw
lightly upon natural resources that are limited and to use, whenever
possible, materials that are abundant. The more volatile fractions
that go to make up gasoline are less plentiful and more expensive
than the heavier constituents that are on the border line between
gasoline and kerosene or burning oil.
Gasoline should, therefore, contain a moderate but not excessive
proportion of low-boiling constituents. There should be sufficient
volatile material to permit ready starting of a cold motor, but not
enough to make the gasoline subject to high evaporation losses and
unnecessarily costly, or dangerous in handling. The limitation of
quantity of low-boiling constituents is particularly important in
airplane gasolines as it obviates certain irregularities in carburetion
that may occur at high altitudes, and reduces somewhat the danger
of fire in case of leakage or breaking of supply tanks.
Ordinary motor gasoline should have a total volatility range wide
enough to include constituents of relatively high-boiling points.
For economic reasons of importance both to the individual user and
the country as a whole, this volatility range should be such that the
gasoline contains the largest possible percentage of the original crude
oil. However, the range should not be wide enough to exceed the
limits of the vaporizing power of the engine. These limits obviously
vary with types of motor design and conditions of use. Thus it
would be expensive folly to specify the same grade of gasoline for
a motor truck that is required for delicately adjusted airplane
engines designed to run most efficiently at altitudes ranging from
10,000 to 20,000 feet.
The general method of determining volatility is to subject gasoline
to an analytical distillation. The results obtained are a function
of the apparatus and method used as well as of the gasoline itself,
and the method used should always be specified as well as the re-
sults. Distillation figures resemble flash-point figures in that in
14
MOTOR GASOLINE.
themselves they mean little. In either case the method and appa-
ratus used should be stated. For example, it should be said a gaso-
line has a certain distillation range with the A. S. T. M. method,
just as it is customary to say that an oil has a given flash point in
the Pensky-Martens closed-cup tester.
DISTILLATION METHODS.
Numerous distillation methods are in use in the petroleum in-
dustry, many of them undesirable and a small number of them based
on sound practical requirements. No one distillation method is good
for all purposes and in issuing this report the bureau has been forced
to select one of several methods having strong claims for superiority.
The most general need seems to be for a distillation method that will
serve to differentiate gasolines reliably and that does not require too
elaborate apparatus or too tedious manipulation. The American
Society for Testing Materials has had occasion to adopt for the
analysis of turpentine substitutes a method that seems to strike the
right combination of simplicity and efficiency and is based on sound.
theoretical principles. To adapt this method to gasoline testing
a few minor changes were necessary, the most important being the
substitution of a thermometer better adapted to gasoline distillation
than the 400° C. instrument specified by the society, and the reading
of temperatures as given amounts distill instead of reading the per-
centages distilling between given temperature limits.
REVIEW OF THE GASOLINE SITUATION.
Before a system of actual specifications is discussed, it seems de-
sirable to summarize the status of the gasoline market in January,
1919. During the last year or two the total production of refinable
crude oil has not increased notably, although the demand for gaso-
line has continued to grow. The supply of gasoline has kept pace
with the demand chiefly because of the use as motor fuel of a greater
proportion of the crude oil refined. Cracking processes have helped
to increase the supply, as also the recovery of gasoline from natural
gas. In addition, many refiners have augmented their production by
what is called "cutting deeper into the crude." Some of the frac-
tions of petroleum that were formerly marketed under other names
and for other purposes are now sold as gasoline, thus in effect in-
creasing gasoline production. This practice has occasioned some dis-
content among users of cars, and statements are frequently made that
motor gasoline now marketed has deteriorated in quality or has been
adulterated. The Bureau of Mines has never detected an actual case
of adulteration among several hundred samples of gasoline collected
in the open market, and is of the opinion that the change in quality
CONSIDERATIONS IN PREPARING GASOLINE SPECIFICATIONS.
15
is not necessarily a deterioration. In any event users are getting
better value for their money than they would if the older types of
"high-test" gasolines were commonly supplied in the market."
Gasoline producing and refining practice, which has been in a
stage of transition during the last three or four years, is even now
unsettled and information regarding the general situation is not in
the possession of the bureau. During the calendar year 1917, when
a survey of the country was made, gasoline marketed on the West
Coast was more volatile than in the East, which in turn was more
volatile than the type generally supplied in the Middle States. Some
recent information indicates that this general condition still exists,
but that there is a tendency toward the general adoption of Mid-
Continent standards.
GENERAL CONSIDERATIONS IN PREPARING GASOLINE SPECIFI-
CATIONS.
Through different sources the Bureau of Mines has been asked to
assist in preparing gasoline specifications. The primary need was
for Federal purchases in the District of Columbia. Later there were
received requests for advice from State and municipal authorities.
who were contemplating the adoption of legal standards for regulat-
ing the quality of gasoline. Finally, the bureau had been required
to aid in formulating specifications for various grades of gasoline
required for military purposes.
In every instance the study of the following two important prob-
lems was necessary: (1) what particular type or types of gasoline
were needed, and (2) how nearly the requirements could be satisfied
in the market. As regards some gasoline, particularly that needed by
the aviation service, the specification of grades that involve special
refinery procedure was necessary. Generally, however, suitable
grades were found in the market.
LIMITS AND REQUIREMENTS OF GASOLINE SPECIFICATIONS.
An ideal system of specifications would, by a minimum of simple
requirements, eliminate all unsatisfactory products without discrim-
inating against any that are desirable. This ideal is impossible to
attain for gasoline, partly because no hard and fast line differentiates
good gasoline from bad, and partly because a satisfactorily simple
specification can not cover all possible sources of discrepancy. In
general, however, the tests discussed later furnish an adequate index
of quality for the normal products marketed as gasoline, and will
a For a detailed discussion of this subject see Dean, E. W.: Fuel for automotive appa-
ratus, Jour. Soc. Automotive Eng., vol. 2, January, 1918, pp. 47 to 53.
16
MOTOR GASOLINE.
probably be satisfactory until such time as new and unforeseen de-
velopments occur in the refining industry.
The requirements that are considered adequate for regulating the
quality of gasoline sold for domestic use are color, freedom from cor-
rosive agents, and volatility. Color is in itself of minor importance
but generally, though not infallibly, indicates whether a gasoline is
properly refined. At present refiners show little tendency to market.
gasolines that do not meet this requirement. The requirement of
freedom from corrosive agents is important, and the simple test or
tests for this property should be made even though the almost uni-
versal care taken by refiners has made it unnecessary.
In deciding upon a system of volatility limits two general factors
must be considered. It is obvious that the points taken in the vola-
tility range must be so selected as to define it. A specification that
fixed only the initial boiling temperature and the 20 per cent
mark would be practically useless; likewise a specification fixing
only the upper distillation limit would be totally inadequate in de-
termining the actual volatility range of gasoline. Therefore the
volatility limits should include points both at the low and high ends
of the distillation range. In addition limitation of some point in
the middle of the curve is desirable as there are moderate possibilities
of variation even if the ends of the curve are defined.
The second general consideration is that limits should be selected
that permit easy and reliable measurement in the laboratory. The
common practice in the industry has been to lay emphasis on so-called
"initial" and "final" boiling temperatures. These points, particu-
larly the former, are exceedingly difficult to determine with pre-
cision. Countless disputes and disagreements have occurred because
of attempts to specify volatility in terms of these two troublesome
points. Experience has shown that the various percentage marks
between the limits of 10 and 90 per cent are easy to determine re-
liably, and that even as low a mark as the 5 per cent point is notably
more reliable than the initial boiling point. In its own laboratories
the Bureau of Mines has had little trouble in getting check results
in "dry-point" (one definition of final boiling temperature) determi-
nations, but has been informed of numerous discrepances among the
results of different analytical laboratories. The bureau believes that
specifications may require the measurement of final boiling tempera-
ture but that this limit should allow a sufficiently wide margin so
that discrepancies in laboratory determinations will not discriminate
against any properly refined gasolines that have a satisfactory 90
per cent mark.
The bureau recommends fixing the more volatile (low boiling) end
of the distillation range by placing an upper and a lower limit on
CONSIDERATIONS IN PREPARING GASOLINE SPECIFICATIONS.
17
some selected temperature mark between the limits of 5 per cent and
20 per cent. The upper limit is necessary to insure the presence in
the gasoline of enough low-boiling constituents to permit ready start-
ing of a cold motor. The lower limit is to prevent the marketing of
gasolines that are unnecessarily dangerous and subject to high evap-
oration losses. As regards facility of examination in the laboratory,
the 20 per cent limit is most desirable, but if close regulation of qual-
ity is desired, as for aviation gasoline, it may be advisable to take a
mark as low as the 5 per cent point.
PROPOSED SPECIFICATIONS FOR GASOLINE.
As already stated, the bureau believes that no one set of specifica-
tions is satisfactory for all needs. The following system is sug-
gested, however, as a simple and satisfactory scheme for regulating
the quality of ordinary automobile gasoline:
Requirements.—Water white.
COLOR.
Method of determination.-Inspection of the vertical column in
a 4-ounce sample bottle or 100 c. c. graduate.
DISCUSSION.
This simple test furnishes a fair but not infallible indication as to
the care with which gasoline is refined.
ACIDITY.
Requirement. Total absence of free or combined acid.
Method of determination.—The residue in the flask after comple-
tion of an analytical distillation shall be shaken thoroughly with
1 c. c. of distilled water. The water extract shall be neutral in re-
action. This may be determined by the use of any satisfactory
indicator. Freedom from acidity is indicated by failure to color.
blue litmus paper pink, by failure to develop a reddish color when
a few drops of methyl orange solution is added, or by the develop-
ment of a red color on addition of a few drops of phenophthalein
solution and one drop of hundredth normal sodium hydroxide solu-
tion.
DISCUSSION.
The experience of the Bureau of Mines indicates that an acid re-
action is rarely or never discovered when the original gasoline is
shaken with distilled water and the aqueous extract tested with a
suitable indicator. Information has been received that carelessly
α
a Chemists of the Atlantic Refining Co. have advised the bureau that an acid reaction
is sometimes discovered in the distillation residue when the original product appears to
be neutral.
97556°-19- -3
、
18
MOTOR GASOLINE.
refined gasoline sometimes contains acid compounds that decompose
in the course of the distillation and leave free acid in the residue in
the flask. This has led to recommendation of the test described
above rather than the test given in Technical Paper 166.
VOLATILITY.
Requirements.-The gasoline shall, when distilled by the method
described hereafter, meet the following requirements:
(a) The temperature read on the thermometer when 20 per cent
has distilled shall not be below 70° C. (158° F.), nor above what-
ever limit is fixed after due consideration of conditions of use.
(b) The temperature read when 90 per cent has distilled shall not
be above another limit similarly chosen.
(c) The temperature read when 50 per cent has distilled shall not
be higher than a mark halfway between the upper 20 per cent limit
and the 90 per cent limit.
(d) The dry point shall not exceed the 90 per cent limit by more
than 40° C. (72° F.).
DISCUSSION OF TEMPERATURE LIMITS.
Several of the marks specified need not necessarily be fixed exactly
as indicated above. The Bureau of Mines considers the 20 per cent
point the most satisfactory low limit but recognizes that there is no
great advantage over any other point between 5 per cent and 20 per
cent. The 50 per cent point is recommended simply because no other
intermediate point seems preferable.. The 90 per cent point has been
proven by experience to be the highest mark that is not likely to vary
with slight discrepancies in experimental operation. "Dry point ”
is one of several possible definitions of final boiling temperature.
The experience of the bureau has been that this point offers the
greatest possibility of experimental agreement of the various marks
used for final boiling temperature, but that it is difficult to formu-
late a definition that renders misunderstanding impossible. The
bureau does not not approve of the definition that involves reading
the temperature as the bottom of the flask goes dry or when a puff
of white vapor is observed. Any percentage point between the limits
of 96 to 98 per cent, however, may be used as a final mark, but care
must be taken not to label it a "dry point."
DISTILLATION METHOD AND APPARATUS.
The distillation method recommended by the bureau is approxi-
mately that adopted by Subcommittee XI of Committee D1 of the
American Society for Testing Materials."
a American Society for Testing Materials, Year Book for 1915, pp. 568-569; or pt. 1,
Committee Reports, 1916, vol. 16, pp. 518-521.
DISTILLATION METHOD AND APPARATUS.
19
The two noticeable points of variation are the method of reading
temperatures against fixed percentage points and the use of a ther-
mometer of lower range. The method of the society is proposed for
the analysis of turpentine substitutes which are petroleum products
of higher boiling range than gasoline.
The apparatus used should be as follows. The particular form
employed by the bureau is represented in figure 1 and differs some-
what in appearance, though not in the essential details, from that
generally supplied in the market for this test.
да

e
g
b
f
Scale in inches
0 1 2 3 4 5 6 7 8 9 10
Scale in centimeters
0 4 8 12 16 20 24
HOM
α
FIGURE 1.-Apparatus used by the Bureau of Mines for distillation test of gasoline.
a Wires connecting with electric mains through a suitable rheostat. b Electric heater.
c Engler distillation flask filled with charge of gasoline partly distilled. d Thermome-
ter. e Condenser, with trough filled with ice and water. f Receiving graduate. g Cock
for draining condenser trough.
FLASK.
The flask used shall be the standard 100 c. c. Engler flask, described
in the various textbooks on petroleum. Dimensions (outside) are as
follows:
Dimensions.
Diameter of bulb_.
Diameter of neck_
Length of neck__
Length of vapor tube__
Dimensions of flask.
Diameter of vapor tube---.
Cm.
Inches.
6. 5
2.56
1.6
0.63
15.0
5.91
10. 0
3.94
0.6
0.24
20
MOTOR GASOLINE.
Position of vapor tube, 9 cm. (3.55 inches) above the surface of the gasoline
when the flask contains its charge of 100 c. c. The tube is approximately in
the middle of the neck.
The flask shall be supported on a ring of asbestos having a circular
opening 11 inches in diameter; this means that only this limited por-
tion of the flask is to be heated. The use of wire gauze or a sand
bath is not approved.
CONDENSER.
The condenser shall consist of a thin walled tube of metal (brass
or copper) approximately one-half inch internal diameter and 22
inches long. It shall be set at an angle of 75° from the perpen-
dicular and shall be surrounded with a cooling jacket of the trough
type. The lower end of the condenser shall be cut off at an acute
angle and shall be curved down for a length of 3 inches. The con-
denser jacket shall be 15 inches long.
THERMOMETER.
The accuracy of distillation depends primarily on the accuracy of
the thermometer and on this account the instrument should be de-
fined so that the results of different analysts may check. The ther-
mometer described in the report of the American Society for Testing
Materials is not adapted for use with gasoline. Its range is un-
necessarily high and the lower temperatures are difficult to read,
because of interference of the cork in the neck of the distillation flask.
The present discussion does not deal with the details of tempera-
ture measurement, but simply indicates requirements that should
be met and that will insure the maximum variations in thermometer
readings at different analytical laboratories not to exceed 1° to 2° C.
Briefly, the thermometer should be an accurate nitrogen-filled
instrument with a short bulb (length 10 to 15 mm., 0.39 to 0.59
inch) and with the mark for 35° C. (95° F.) at a distance between
100 and 120 mm. (3.94 to 4.75 inches) from the top of the bulb.
The thermometer should be scaled for total immersion.
The above requirements almost always permit the lowest tempera-
ture registered to be read above the cork of the distillation flask,
and variations due to the so-called stem correction will always be
practically the same. The stem correction should not be applied,
but it should be understood that results of distillations are expressed
in terms of thermometer readings and not in terms of actual tempera-
tures. The use of partial-immersion thermometers is not recom-
mended for distillations, as these instruments are no more likely to
agree with one another than are the more common total-immersion
thermometers.
DISTILLATION METHOD AND APPARATUS.
21
The following specification for a gasoline distillation thermometer
is offered so that the prospective purchaser may be able to state defi-
nitely what he requires and by so doing obtain a satisfactory instru-
ment. The specification has been submitted to several manufacturers
of thermometers, who state that it insures the obtaining of a satis-
factory high-grade instrument without imposing on the maker un-
necessary and troublesome restrictions that increase the cost.
SPECIFICATIONS FOR GASOLINE DISTILLATION THERMOMETER.
The thermometer should be made of selected enamel-backed
tubing having a diameter between 5.5 and 7 mm. The bulb should
be of Jena normal or Corning normal glass; its diameter should be
less than that of the stem and its length between 10 and 15 mm.
The total length of the thermometer should be approximately 380
mm. The range should cover 0° C. to 270° C., with the length of
The
the graduated portion between the limits of 210 to 250 mm.
point marking a temperature of 35° C. should be not less than 100
mm. nor more than 120 mm. from the top of the bulb.
a
The scale should be graduated for total immersion. The accuracy
must be within about 0.5° C. The space above the meniscus must be
filled with an inert gas, such as nitrogen, and the stem and bulb
must be thoroughly aged and annealed before being graduated.
All material and workmanship must be of the best. The scale
shall be marked for single-degree intervals. Each tenth degree shall
be numbered and each fifth degree distinguished by a longer mark.
SOURCE OF HEAT IN GASOLINE DISTILLATION.
Ъ
The source of heat in distilling gasoline may be a gas burner, an
alcohol lamp, or an electric heater. The commonly used Tirrell type
of gas burner is moderately satisfactory, but a burner having a
smaller orifice and a more sensitive regulating valve is more
desirable. Such a burner has been developed and is used by the
Philadelphia laboratory of the Atlantic Refining Co., and is de-
scribed and shown in diagram in a recent journal article published
by permission of the bureau. Alcohol lamps may be employed in lab-
oratories lacking a satisfactory gas supply. A type that has been
tried by the bureau and found satisfactory is sold by the C. J. Tag-
liabue Mfg. Co., Brooklyn, N. Y. For the bulk of its own work the
bureau has used specially designed and constructed electric heaters
which have proved considerably more satisfactory than either gas or
a If desired, a Fahrenheit thermometer may be obtained on these specifications by sub-
stituting Fahrenheit equivalents for the several centigrade marks.
Dean, E. W., A convenient electric heater for use in the analytical distillation of
gasoline Jour. Ind. and Eng. Chem., vol. 10 (October, 1918), pp. 823-826.
22
MOTOR GASOLINE.
alcohol burners. This type of electric heater is described in the jour-
nal article referred to in connection with the Atlantic Refining Co.
gas burner.
Electric heaters are superior to the other types in that they permit.
more exact regulation of the degree of heat, are not subject to serious
uncontrollable fluctuation (such as is caused by air currents) and
involve a minimum danger of fire.
PROCEDURE AND DETAILS OF MANIPULATION IN CONDUCTING
DISTILLATIONS.
1. If an electric heater is used it is started first to warm it.
2. The condenser box is filled with water containing a liberal pro-
portion of cracked ice.
3. The charge of gasoline is measured into the Engler flask from
a 100 c. c. graduate. This graduate is used as a receiver for dis-
tillates without any drying. This procedure eliminates errors due to
incorrect scaling of graduates and also avoids the creation of an ap-
parent distillation loss due to the impossibility of draining the gaso-
line entirely from the graduate.
4. The above-mentioned graduate is placed under the lower end of
the condenser tube so that the latter extends downward below the
top of the graduate at least 1 inch. The condenser tube should be so
shaped and bent that the tip can touch the wall of the graduate on
the side adjacent to the condenser box. This detail permits dis-
tillates to run down the side of the graduate and avoids disturbance
of the meniscus caused by the falling of drops. The graduate is
moved occasionally to permit the operator to ascertain that the
speed of distillation is right, as indicated by the rate at which drops
fall. The proper rate is from 4 c. c. to 5 c. c. per minute, which is
approximately two drops a second. The top of the graduate is cov-
ered, preferably by several thicknesses of filter paper, the condenser
tube passing through a snugly fitting opening. This minimizes
evaporation losses due to circulation of air through the graduate
and also excludes any water that may drip down the outside of the
condenser tube on account of condensation on the ice-cooled conden-
ser box.
5. A boiling stone (a bit of unglazed porcelain or other porous
material) is dropped into the gasoline in the Engler flask. The
thermometer, equipped with a well-fitted cork and with its bulb
covered with a thin film of absorbent cotton (preferably the long-
fibered variety sold for surgical dressings), is fitted into the flask
with the thermometer bulb just below the lower level of the side neck
opening. The flask is connected with the condenser tube.
6. Heat is applied cautiously and the gasoline brought to its boil-
ing point. In case it is desired to record the initial boiling point
DETAILS OF MANIPULATION IN CONDUCTING DISTILLATIONS.
23
the thermometer is read when the first drop falls from the end of
the condenser tube into the graduate. The amount of heat is then
increased so that the distillation proceeds at a rate of from 4 c. c. to
5 c. c. per minute. The thermometer is read as each of the selected
percentage marks is reached. In case maximum boiling point or
dry point (one definition of end point) is to be measured, the heating
is continued after the flask bottom has boiled dry until the column
of mercury reaches a maximum and then starts to recede con-
sistently.
7. Distillation loss is determined as follows: The condenser tube
is allowed to drain for at least five minutes after heat is shut off, and
a final reading taken of the quantity of distillate collected in the
receiving graduate. The distillation flask is removed from the con-
denser and thoroughly cooled as soon as it can be handled. This
can be accomplished by using first an air bath and then immersing
the bulb of the flask in the ice-water mixture in the condenser trough.
The condensed residue is poured into a small graduate or graduated
test tube and its volume measured. This residue is of course re-
tained for the acidity test which has been described in an earlier
connection. The sum of its volume and the volume collected in the
receiving graduate, substracted from 100 c. c. gives the figure for
distillation loss. In case this loss exceeds 2 per cent, a check dis-
tillation should be run to ascertain whether such loss is due to the
presence of highly volatile constituents or to failure to condense the
lighter fractions on account of too strong heating at the beginning
of the distillation.
DISCUSSION OF DETAILS OF PROCEDURE.
Some of the prescribed details of procedure merit discussion. The
use of a boiling stone is desirable to prevent "bumping," which
occasionally occurs, especially when the Engler flask is new or freshly
cleaned." The film of cotton on the thermometer bulb retains a
layer of condensed gasoline and insures against superheating, either
in the course of the distillation or at the end point. Superheating
manifests itself as an irregular fluctuation of the thermometer dur-
ing distillation, or as an abnormal rise at the end. The film of
cotton should be very thin and in case of doubt the quantity used
(5 to 10 milligrams) should be weighed. If the material used is the
long-fibered cotton sold for surgical purposes, the film rarely needs.
renewing as, if properly applied, it adheres tenaciously to the ther-
mometer bulb.
This can
a Engler flasks should be occasionally cleaned to remove deposits of carbon.
be easily accomplished by filling the bulb with chromic-sulphuric acid cleaning mixture
and allowing to stand over night.
24
MOTOR GASOLINE.
Avoidance of an excessive distillation loss is important, as other-
wise the temperature readings will be abnormally high. If blends.
containing considerable proportions of casing-head gasoline are dis-
tilled, it may be necessary to use an ice-salt freezing mixture in the
condenser trough and to keep the receiving graduate immersed in a
mixture of ice and water (preferably not the ice-salt freezing mix-
ture). If this is done the gasoline must be cooled in ice and water
before measuring it into the flask, or else a suitable allowance (ap-
proximately 3 per cent) must be made for the contraction of the
gasoline due to cooling it from room temperature to the freezing
point of water.
ADDITIONAL ANALYTICAL METHODS EMPLOYED IN THE TESTING
OF GASOLINE.
In addition to the tests described in connection with the suggested
system of specifications there are various analytical methods em-
ployed, sometimes for more elaborate types of specifications and
sometimes for the purpose of obtaining information of a general
nature. Some of the more important of these tests are listed and
described as follows:
66
THE DOCTOR" TEST.
The "doctor" test is largely employed by refineries for detecting
the presence of certain types of decomposable sulphur compounds.
It does not determine the actual presence or absence of sulphur in
gasoline, and, in fact, products that have been refined to pass this
test are likely to contain a larger percentage of sulphur than before.
treatment. But gasoline not passing the doctor test is likely to
decompose in storage with the development of a yellow color and an
offensive odor. In addition, there is a possibility that gasoline "sour"
to the doctor test may have been the cause of certain reported cor-
rosion of metal parts of carburetors.
The doctor test shall be conducted and interpreted as follows: "
Obtain pure flowers of sulphur and prepare the sodium plumbite
or doctor solution. For the latter, dissolve approximately 125 grams
of sodium hydroxide (NaOH) in a liter of distilled water, add
60 to 70 grams of litharge (PbO) and shake vigorously for 15 to 30
minutes, or let it stand with occasional shaking for a day. Allow
it to settle and pour or siphon off the clear liquid. If the solution
fails to settle properly it may be filtered through a mat of asbestos.
The solution must be kept in a bottle closed tightly with a cork
stopper.
a The bureau was aided in formulating a description of this test by C. J. Robinson,
chemist of the Standard Oil Co. of New Jersey.
.-
ANALYTICAL METHODS EMPLOYED IN TESTING GASOLINE. 25
In making the test shake together vigorously two volumes of gaso-
line and one volume of the doctor solutiton (10 c. c. and 5 c. c are
convenient quantities) in a test tube; or, if preferred, an oil sample
bottle may be used with correspondingly larger quantities. After
shaking together for about 15 seconds, add a small pinch of flowers
of sulphur, shake the tube again for 15 seconds and allow the contents
to settle. The quantity of sulphur used shall be such that practically
all of it floats on the surface separating the gasoline from the doctor
solution.
If the gasoline is discolored, or if the sulphur film is so dark that
its yellow color is noticeably masked, the test shall be reported as
positive and the gasoline condemned as "sour." If the liquid re-
mains unchanged in color and if the sulphur film is bright yellow
or only slightly discolored with gray or flecked with black, the test
shall be reported negative and the gasoline considered "sweet."
CORROSION AND GUMMING TEST.
A test involving evaporation of gasoline in a polished copper dish
was devised by F. C. Robinson and his associates of the Atlantic
Refining Co. for determining the purity of airplane gasoline. The
Bureau of Mines as yet lacks information on the desirability of ap-
plying this test generally to motor fuel, but is including a descrip-
tion of it for general information. The test seems to be a severe
one, and failure to pass it may not mean that a gasoline is not sat-
isfactory for ordinary uses.
A charge of gasoline is evaporated to dryness on a steam bath
in a freshly polished hemispherical copper dish about 3 inches in
diameter. The dish is filled to within about three-fourths of an inch
of the top, or a charge of 100 c. c. is measured in from a pipette.
The bottom of the dish must not be colored gray or black, as will
be the case if elementary sulphur is contained in the gasoline. The
presence of a peacock-colored deposit does not indicate sufficient sul-
phur to condemn the gasoline.
It is specified that a weighable residue shall not remain in the
dish. Some preliminary experiments made by the bureau have indi-
cated that the maximum allowable residue should be 0.03 per cent
of the charge of gasoline evaporated.
UNSATURATION TEST.
Certain types of gasoline, particularly those derived from cracking
processes, contain olefin and similar hydrocarbons. A simple test for
determining the relative proportion of these constituents is furnished
26
MOTOR GASOLINE.
by the sulphuric acid absorption method. The bureau recommends
the following procedure:"
The container recommended is that described in the catalogues of
chemical supply houses as a 6-inch, 9-gram, 50 per cent Babcock
cream bottle. The neck of such a bottle is calibrated for the volume
of 4.5 grams of butter fat which is approximately 5 c. c. An ordi-
nary 5 c. c. pipette can be regraduated to deliver this quantity. The
gasoline to be tested is measured into a clean, dry Babcock bottle,
cooled by immersion for a minute or two in ice water, after which
200 per cent by volume of ordinary concentrated sulphuric acid is.
poured in from a small graduate. Care should be taken that the
acid runs quietly down the side of the bottle, instead of splashing
onto the surface of the gasoline. A rubber stopper is then placed in
the bottle and the contents are shaken, first slowly, then vigorously
with a rotary motion for several minutes. The gasoline and the acid
are separated by either of the following methods:
GRAVITY SEPARATION.
Sulphuric acid is added to the contents of the bottle until the sur-
face of the liquid is about level with the upper graduation mark on
the neck of the bottle. The mixture is then set aside and allowed to
stand overnight, until practically complete separation is effected.
CENTRIFUGAL SEPARATION.
The stoppered bottle is placed in a suitable centrifuge and re-
volved for two or three minutes at a speed of 500 to 1,000 r. p. m.
Sufficient acid is added to bring the level up to the lower graduation
mark, and the bottle and its contents are again centrifuged to com-
plete the separation. More acid is added to bring the column to the
upper graduation mark, after which the residual volume of gasoline
is read.
VAPOR PRESSURE.
In order to insure safety in the shipment of gasoline by tank car
a vapor pressure test is required. The limit usually prescribed is
10 pounds per square inch.
b
The standard method prescribed by the Bureau of Explosives is
briefly as follows:
APPARATUS.
The apparatus consists of the well-known inspectors' gas gage
(made by the Pittsburgh Gage & Supply Co., Pittsburgh, Pa.) and
a Dean, E. W., and Hill, H. H., Determination of unsaturated hydrocarbons in gaso-
line: Tech. Paper 181, Bureau of Mines, 1917, 25 pp.
Report of the Chief inspector of the Bureau of the Safe Transportation of Explosives
and Other Dangerous Articles, Feb., 1916, pp. 27-30.
FORMS FOR RECORDING RESULTS OF GASOLINE ANALYSES. 27
a metal test cylinder of about 450 c. c. capacity (approximately 9
inches long and 2 inches in diameter, outside dimensions) with an
opening at the top for a standard one-fourth-inch taper screw fit-
ting. Accessories are thermometers, water bath of any convenient
sort, temperature regulating media, and a small measure, the ca-
pacity of which is exactly one-tenth the capacity of the test cylinder.
PROCEDURE.
The test cylinder is filled to exactly 90 per cent of its capacity.
This can be accomplished conveniently by filling to the top and then
pouring out enough to fill the small measure mentioned in the pre-
ceding paragraph. The gage is screwed in tightly and the test
cylinder immersed in water at a temperature of 21° C. (70° F.) and
shaken gently for a few minutes until the gasoline has come to the
temperature of the bath (five minutes is considered sufficient). Then
the gage is unscrewed and the pressure released for a period of 20
seconds. The cylinder is closed again by screwing the gage in, using
if necessary something like liquid shellac to make the joint tight.
The test cylinder is placed in a water bath at 38° C. (100° F.)-
32° C. (90° F.) from November 1 to March 1-with the water level
just below the lower edge of the pressure gage. The water is stirred
continually and the temperature maintained constant for 10 minutes.
The gage is then tapped lightly and the pressure read.
This test is one with which the Bureau of Mines has had little
experience. It seems to be open to objection on the ground that the
pressure developed may be affected by the degree of agitation to
which the gasoline is subjected. The bureau is not, however, in a
position to suggest modifications or improvements.
FORMS FOR RECORDING THE RESULTS OF GASOLINE ANALYSES.
In keeping laboratory records of gasoline analysis the bureau has
had occasion to employ two forms which have proved particularly
convenient and which are reproduced in the present paper for pur-
poses of information. The forms are designed for recording more
information than is needed for specification analyses and are the
types the bureau has selected for its own use. Form 1 is a blank rec-
ord for tabulating results of the physical examination and analysis
of the gasoline. On Form 2 are shown typical distillation curves for
straight refinery and blended casing-head gasolines, to which refer-
ence has already been made.
28
MOTOR GASOLINE.
GASOLINE ANALYSIS.
Sample No..
Gravity...
Color....
Acidity...
Unsaturation..
.Deg. B……….
.Odor....
Doctor test...
Distillation in 100-cc. Engler flask; barom.
- per cent.
MARK
TEMPERATURE
Deg. C:
Deg. F.
First drop
10 per cent
20 per cent
30 per cent
40 per cent
50 per cent
60 per cent
70 per cent
80 per cent
90 per cent
95 per cent
Dry point
.mm.
Average...
Distillation loss..
per cent.
FORM 1.-Form for recording results of gasoline analysis.
Color-..
FORMS FOR RECORDING RESULTS OF GASOLINE ANALYSES. 29
Odor-
Gravity-.....
Unsaturated.....
Doctor,....
Acidity
%Loss,...
180
°C.
160
·
140
U.S. BUREAU OF MINES
MOTOR FUEL
DISTILLATION.

260
240
Be.
220
-500
464
428
200
-392
-356
°F.
-320
120
100
Straight'refinery motor gasoline
80
-284
Blended casinghead motor gasoline
+248
+212
60
-176
40
140
104
20
.68
FIRST 10
DROP
20
30
40 50 60
Percentage Distilled
70 80 90 DRY
POINT
FORM 2 (fig. 2).-Graphic chart for recording results of gasoline analysis.
Form 1 is generally made up as a 3 by 63 inch sheet, punched
for inclosure in a standard size loose-leaf binder or notebook. Form
2 is used as a 63 by 7 inch sheet, which when folded once can be
carried in the same book. Form 2 is generally printed on semi-
transparent paper so that copies of analytical results can be made
by the process of blue printing.
CENTIGRADE-FAHRENHEIT TEMPERATURE TRANSFORMATION TABLE.
On account of the common use of the two temperature scales, centi-
grade and Fahrenheit, some simple means of translating figures re-
corded in these two systems is desirable. Table 1 following has been
employed by the bureau and found particularly convenient.
30
MOTOR GASOLINE.
TABLE 1.-Degrees centigrade to degrees Fahrenheit.

0
1
2
Co
3
4
LO
5
6
7
CC
8
9
01234
32
34 36
37 39
41
43
50
52
54
55
57
59 61 63 64 66
ஐசு
45 46
48
68 70
72
73
75
77
79
81 82 84
86
88
90
91
93
95
97
99 100 102
104 106 108
109
111
113
115 117 118 120
11
14
BOND GENSE
5
122
124
126
127
129
131
133 135 136 138
6
140
142 144
145
147
149
151 153 154 156
7 158 160 162
163
165
167
169
171
172
174
8
176 178 180
181
183
185
187 189
190 192
9
194 196
198
199
201
203
205 207
208 210
10 212
214 216 217
219
221
223 225 226 228
230 232 234 235
237
239
241 243 244 246
12 248 250 252
253
255
257
259 261
262
264
13 266 268 270
271
273
275
277 279 280 282
284
286 288
289
291
293
295 297 298 300
15 302 304 306
307
309
311
313 315 316 318
16 320 322 324
325
327
329
331 333 334 336
17 338 340 342
343
345
347
349 351 352
354
18 356 358 360
361
363
365
367 369 370 372
19 374 376 378
379
381
383
385 387 388 390
23
22222
20
392 394 396 397
399
401
403 405 406 408
21 410
412 414
415
417
419
421 423 424 426
428 430 432
433
435
437
439 441 442 444
446 448 450
451
453
455
457 459 460
462
24 464 466 468
469
471
473
475 477 478 480
25 482 484 486
487
489
491
493 495 496 498
26 500 502 504
505
507
509
511 513 514 516
27
518 520 522 523 525
527
529 531 532 534
28
536
538 540 541 543
545
547 549 550 552
29
554 556 558
559 561
563
565 567 568 570
30 572 574 576 577
31 590 592 594 595
32 608 610 612 613
579
597 599
581
583 585 586 588
601 603 604 606
615
617
619 621 622
624
33 626 628 630 631
633
635
637 639 640
642
34 644 646 648 649
651
653
655 657 658 660
PUBLICATIONS ON PETROLEUM TECHNOLOGY.
A limited supply of the following publications of the Bureau of
Mines has been printed and is available for free distribution until
the edition is exhausted. Requests for all publications can not be
granted, and to insure equitable distribution applicants are requested
to limit their selection to publications that may be of especial interest
to them. Requests for publications should be addressed to the
Director Bureau of Mines.
The Bureau of Mines issues a list showing all its publications
available for free distribution as well as those obtainable only from
the Superintendent of Documents, Government Printing Office, on
payment of the price of printing. Interested persons should apply
to the Director, Bureau of Mines, for a copy of the latest list.
PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION.
BULLETIN 120. Extraction of gasoline from natural gas by absorption
methods, by G. A. Burrell, P. M. Biddison, and G. G. Oberfell. 1917. 71 pp.,
2 pls., 15 figs.
BULLETIN 134. The use of mud-laden fluid in oil and gas wells, by J. O.
Lewis and W. F. McMurray. 1916. 86 pp., 3 pls., 18 figs.
BULLETIN 148. Methods for increasing the recovery from oil sands, by J. O.
Lewis. 1917. 128 pp., 4 pls., 32 figs.
BULLETIN 149. Bibliography of petroleum and allied substances-1915, by
E. H. Burroughs. 1917. 147 pp.
BULLETIN 158. Cost accounting for oil producers, by C. G. Smith. 1917.
123 pp.
BULLETIN 162. Removal of lighter hydrocarbons, by J. M. Wadsworth. 1918.
164 pp., 50 pls., 45 figs.
BULLETIN 163. Methods of shutting off water in oil or gas wells, by F. B.
Tough. 1918. 122 pp., 20 pls., 7 figs.
BULLETIN 170. Extinguishing and preventing oil and gas fires, by C. P. Bowie.
1918. 50 pp., 19 pls., 4 figs.
TECHNICAL PAPER 32. The cementing process of excluding water from oil
wells, as practiced in California, by Ralph Arnold and V. R. Garfias. 1913.
12 pp., 1 fig.
TECHNICAL PAPER 38. Wastes in the production and utilization of natural
gas, and methods for their prevention, by Ralph Arnold and F. G. Clapp. 1913.
29 pp.
TECHNICAL PAPER 42. The prevention of waste of oil and gas from flowing
wells in California, with a discussion of special methods used by J. A. Pollard,
by Ralph Arnold and V. R. Garfias. 1913. 15 pp., 2 pls., 4 figs.
TECHNICAL PAPER 45. Waste of oil and gas in the Mid-Continent fields, by
R. S. Blatchley. 1914. 54 pp., 2 pls., 15 figs.
31
32
MOTOR GASOLINE.
TECHNICAL PAPER 49. The flash point of oils, methods and apparatus for
its determination, by I. C. Allen and A. S. Crossfield. 1913. 31 pp., 2 figs.
TECHNICAL PAPER 66. Mud-laden fluid applied to well drilling, by J. A. Pol-
lard and A. G. Heggem. 1914. 21 pp., 12 figs.
TECHNICAL PAPER 68. Drilling wells in Oklahoma by the mud-laden fluid
method, by A. G. Heggem and J. A. Pollard. 1914. 27 pp., 5 figs.
TECHNICAL PAPER 72. Problems of the petroleum industry, results of con-
ferences at Pittsburgh, Pa., August 1 and September 10, 1913, by I. A. Allen.
1914. 20 pp.
TECHNICAL PAPER 79. Electric lights for oil and gas wells, by H. H. Clark.
1914. 8 pp.
TECHNICAL PAPER 87. Methods of testing natural gas for gasoline content, by
G. A. Burrell and G. W. Jones. 1916. 26 pp., 7 figs.
TECHNICAL PAPER 117. Quantity of gasoline necessary to produce explosive
vapors in sewers, by G. A. Burrell and H. T. Boyd. 1916. 18 pp., 4 figs.
TECHNICAL PAPER 120. A bibliography of the chemistry of gas manufacture,
by W. F. Rittman and M. C. Whittaker, compiled and arranged by M. S. Howard.
1915. 30 pp.
TECHNICAL PAPER 127. Hazards in handling gasoline, by G. A. Burrell. 1915.
12 pp.
TECHNICAL PAPER 131. The compressibility of natural gas at high pressures,
by G. A. Burrell and I. W. Robertson. 1916. 11 pp., 2 figs.
TECHNICAL PAPER 158. Compressibility of natural gas and its constituents, with
analyses of natural gas from 31 cities in the United States, by G. A. Burrell
and I. W. Robertson. 1917. 16 pp., 9 figs.
TECHNICAL PAPER 161. Construction and operation of a single-tube cracking
furnace for making gasoline, by C. P. Bowie. 1916. 16 pp., 10 pls.
TECHNICAL PAPER 163. Physical and chemical properties of gasoline sold
throughout the United States during the calendar year 1915, by W. F. Rittman,
W. A. Jacobs, and E. W. Dean. 1916. 45 pp., 4 figs.
TECHNICAL PAPER 181. Determination of unsaturated hydrocarbons in gasoline,
by E. W. Dean and H. H. Hill. 1917. 25 pp.
TECHNICAL PAPER 185. Use of the interferometer in gas analysis, by F. M.
Seibert and W. C. Harpster. 1918. 18 pp., 1 pl., 5 figs.
PUBLICATIONS THAT MAY BE OBTAINED ONLY THROUGH THE SUPERIN-
TENDENT OF DOCUMENTS.
BULLETIN 19. Physical and chemical properties of the petroleums of the San
Joaquin Valley, Cal., by I. C. Allen and W. A. Jacobs, with a chapter on analyses
of natural gas from the southern California oil fields, by G. A. Burrell. 1911.
60 pp., 2 pls., 10 figs. 10 cents.
BULLETIN 32. Commercial deductions from comparisons of gasoline and alco-
hol tests on internal-combustion engines, by R. M. Strong. 1911. 38 pp. 5 cents.
BULLETIN 43. Comparative fuel values of gasoline and denatured alcohol in
internal-combustion engines, by R. M. Strong and Lauson Stone. 1912. 243 pp.,
3 pls., 32 figs. 20 cents.
BULLETIN 65. Oil and gas wells through workable coal beds; papers and dis-
cussions, by C. S. Rice, O. P. Hood, and others. 1913. 101 pp., 1 pl., 11 figs.
10 cents.
BULLETIN 88. The condensation of gasoline from natural gas, by G. A.
Burrell, F. M. Seibert, and G. G. Oberfell. 1915. 106 pp., 6 pls., 18 figs.
15 cents.
PUBLICATIONS ON PETROLEUM TECHNOLOGY.
33
BULLETIN 114. Manufacture of gasoline and benzene-toluene from petroleum
and other hydrocarbons, by W. F. Rittman, C. B. Dutton, and E. W. Dean,
with a bibliography compiled by M. S. Howard. 1915. 258 pp., 9 pls., 45 figs.
35 cents.
BULLETIN 125. The analytical distillation of petroleum, by W. F. Rittman
and E. W. Dean. 1916. 79 pp., 1 pl., 16 figs. 15 cents.
TECHNICAL PAPER 3. Specifications for the purchase of fuel oil for the Gov-
ernment, with directions for sampling oil and natural gas, by I. C. Allen.
1911. 13 pp. 5 cents.
TECHNICAL PAPER 10. Liquified products of natural gas, their properties and
uses, by I. C. Allen and G. A. Burrell. 1912. 23 pp., 5 cents.
TECHNICAL PAPER 25. Methods for the determination of water in petroleum
and its products, by I. C. Allen and W. A. Jacobs. 1912. 13 pp., 2 figs. 5 cents.
TECHNICAL PAPER 26. Methods for the determination of the sulphur content of
fuels, especially petroleum products, by I. C. Allen and I. W. Robertson. 1912.
13 pp., 1 fig. 5 cents.
TECHNICAL PAPER 36. The preparation of specifications for petroleum prod-
ucts, by I. C. Allen. 1913. 12 pp., 5 cents.
TECHNICAL PAPER 37. Heavy oil as fuel for internal-combustion engines, by
I. C. Allen. 1913. 36 pp. 5 cents.
TECHNICAL PAPER 51. Possible causes of the decline of oil wells, and suggested
methods of prolonging yield, by L. G. Huntley. 1913. 32 pp. 9 figs. 5 cents.
TECHNICAL PAPER 53. Proposed regulations for the drilling of oil and gas
wells, with comments thereon, by O. P. Hood and A. G. Heggem. 1913. 28 pp.,
2 figs. 5 cents.
TECHNICAL PAPER 57. A preliminary report on the utilization of petroleum
and natural gas in Wyoming, by W. R. Calvert, with a discussion of the suit-
ability of natural gas for making gasoline, by G. A. Burrell. 1912. 23 pp.
5 cents.
TECHNICAL PAPER 70. Methods of oil recovery in California, by Ralph Arnold
and V. R. Garfias. 1914. 57 pp., 7 figs. 5 cents.
TECHNICAL PAPER 74. Physical and chemical properties of the petroleums of
California, by I. C. Allen, W. A. Jacobs, A. S. Crossfield, and R. R. Matthews.
1914. 38 pp., 1 fig. 5 cents.
TECHNICAL PAPER 104. Analysis of natural gas and illuminating gas by
fractional distillation in a vacuum at low temperatures and pressures, by G. A.
Burrell, F. M. Seibert, and I. W. Robertson. 1915. 41 pp., 7 figs. 5 cents.
TECHNICAL PAPER 109. Composition of the natural gas used in 25 cities, with
a discussion of the properties of natural gas, by G. A. Burrell and G. G.
Oberfell. 1915. 22 pp. 5 cents.
TECHNICAL PAPER 115. Inflammability of mixtures of gasoline vapor and air,
by G. A. Burrell and H. T. Boyd. 1915. 18 pp., 2 figs. 5 cents.
TECHNICAL PAPER 130. Underground wastes in oil and gas fields and methods
of prevention, by W. F. McMurray and J. O. Lewis. 1916. 28 pp., 1 pl., 8 figs.
O
1
UNIVERSITY OF MICHIGAN
3 9015 06456 5214
Medical Library