ASTM D2505-88(1998)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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An American National Standard
Designation:D2505–88 (Reapproved 1998)
Standard Test Method for
Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-
Purity Ethylene by Gas Chromatography
This standard is issued under the fixed designation D 2505; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope helium as the carrier gas. Methane and ethane are determined
by using a silica gel column. Propylene and heavier hydrocar-
1.1 This test method covers the determination of carbon
bons are determined using a hexamethylphosphoramide
dioxide, methane, ethane, acetylene, and other hydrocarbons in
(HMPA) column. Acetylene is determined by using, in series,
high-purity ethylene. Hydrogen, nitrogen, oxygen, and carbon
a hexadecane column and a squalane column. Carbon dioxide
monoxide are determined in accordance with Test Method
is determined using a column packed with activated charcoal
D 2504. The percent ethylene is obtained by subtracting the
impregnated with a solution of silver nitrate in b,b8-
sum of the percentages of the hydrocarbon and nonhydrocar-
oxydipropionitrile. Columns other than those mentioned above
bon impurities from 100. The method is applicable over the
may be satisfactory. (see 5.3.) Calibration data are obtained
range of impurities from 1 to 500 parts per million volume
using standard samples containing the impurities, carbon
(ppmV).
dioxide, methane, and ethane in the range expected to be
1.2 This standard does not purport to address all of the
encountered. Calibration data for acetylene are obtained as-
safety concerns, if any, associated with its use. It is the
suming that acetylene has the same peak area response on a
responsibility of the user of this standard to establish appro-
weight basis as methane. The acetylene content in a sample is
priate safety and health practices and determine the applica-
calculatedonthebasisoftheratioofpeakareaoftheacetylene
bility of regulatory limitations prior to use. For some specific
peak to the peak area of a known amount of methane.
hazard statements, see Notes 8 and 9.
Calculations for carbon dioxide, methane, and ethane are
1.3 The values stated in acceptable metric units are to be
carried out by the peak-height measurement method.
regarded as the standard. The values in parentheses are for
information only.
4. Significance and Use
2. Referenced Documents 4.1 High-purity ethylene is required as a feedstock for some
manufacturing processes, and the presence of trace amounts of
2.1 ASTM Standards:
carbon dioxide and some hydrocarbons can have deleterious
D 2504 Test Method for Noncondensable Gases in C and
2 effects. This method is suitable for setting specifications, for
Lighter Hydrocarbon Products by Gas Chromatography
use as an internal quality control tool and for use in develop-
D 4051 Practice for Preparation of Low-Pressure Gas
3 ment or research work.
Blends
E 260 Practice for Packed Column Gas Chromatography
5. Apparatus
F 307 PracticeforSamplingPressurizedGasforGasAnaly-
5 5.1 Any chromatographic instrument with an overall sensi-
sis
tivity sufficient to detect 2 ppmV or less of the compounds
3. Summary of Test Method listed with a peak height of at least 2 mm without loss of
resolution.
3.1 The sample is separated in a gas chromatograph system
5.2 Detectors—Thermal Conductivity—If a methanation re-
utilizing four different packed chromatographic columns with
actor is used, a flame ionization detector is also required. To
determine carbon dioxide with a flame ionization detector, a
This test method is under the jurisdiction of ASTM Committee D-2 on
methanation reactor must be inserted between the column and
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
the detector and hydrogen added as a reduction gas (see Test
D02.D0.02on C Test Methods.
Method D 2504, Appendix X1).
Current edition approved Oct. 31, 1988. Published December 1988. Originally
published as D 2505 – 66 T. Last previous edition D 2505 – 83. 5.3 Column—Any column or set of columns can be used
Annual Book of ASTM Standards, Vol 05.01.
that separates carbon dioxide, methane, acetylene and C and
Annual Book of ASTM Standards, Vol 05.02.
heavier compounds. There may be tailing of the ethylene peak
Annual Book of ASTM Standards, Vol 14.02.
but do not use any condition such that the depth of the valleys
Annual Book of ASTM Standards, Vol 15.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2505
ahead of the trace peak is less than 50 % of the trace peak
height. (See Fig. 1 for example.)
5.4 Recorder—A recorder with a full-scale response of 2 s
or less and a maximum rate of noise of 60.3 % of full scale.
5.5 Gas-BlendingApparatus—Atypical gas-blending appa-
ratus is shown in Fig. 2. A high-pressure manifold equipped
withagagecapableofaccuratelymeasuringethylenepressures
up to 3.4 MN/m gage (500 psig) is required. Other types of
gas-blending equipment, such as described in Practice D 4051,
can be used.
NOTE 1— Practice E 260, contains information that will be helpful to
those using this method.
6. Reagents and Materials
6.1 CopperorAluminum,orStainlessSteelTubing, 6.4-mm
1 1
( ⁄4-in. ) outside diameter, and nylon tubing, 3.2-mm ( ⁄8-in.)
outside diameter.
6.2 Solid Supports—Crushed firebrick or calcined diatoma-
ceous earth, such as Chromosorb P, 35 to 80-mesh and 80 to
FIG. 2 Gas-Blending Manifold
100-mesh. Other supporting materials or mesh sieves can be
NOTE 3—Warning: HMPA may be harmful if inhaled. Causes irrita-
satisfactory.
7 tion. A potential carcinogen (lungs). See A1.5.
6.3 Active Solids—Activated carbon, 30 to 40-mesh, silica
gel, 100 to 200-mesh. Other sizes may be satisfactory. 6.5 Helium.
6.4 Liquid Phases—Hexamethylphosphoramide (HMPA ),
NOTE 4—Warning: Compressed Gas, Hazardous Pressure. See A1.2.
9 9
hexadecane. Squalene, silver nitrate, and b,b8-
6.6 Hydrogen.
oxydipropionitrile. Other liquid phases may be satisfactory.
NOTE 5—Warning: Flammable Gas, Hazardous Pressure. See A1.6.
NOTE 2—Warning: Combustible solvents. See A1.7.
6.7 Acetone.
NOTE 6—Extremely Flammable. See A1.1.
Available from the Celite Division, Johns Mansville Co., New York, NY.
7 6.8 Gases for Calibration—Pure or research grade carbon
A fraction sieved in the laboratory to 30 to 40 mesh from medium activity
dioxide, methane, ethane, acetylene, ethylene, propane, and
charcoal, 20 to 60 mesh, sold by Central Scientific Co., 1700 Irving Park Road,
Chicago, IL 60613, has been found satisfactory for this purpose.
propylene. Certified calibration blends are commercially avail-
Silica gel Code 923 available from the Davison Chemical Co., Baltimore, Md.
able from numerous sources and may be used.
21203, has been found satisfactory for this purpose.
Available from the Fisher Scientific Co., St. Louis, MO.
NOTE 7—Warning: Flammable Gases, Hazardous Pressure. See A1.2
b,b8-oxydipropionitrile, sold by Distillation Products Industries, Division of
and A1.3.
Eastman Kodak Co., Rochester, NY, has been found to be satisfactory.
6.9 Methanol.
NOTE 8—Warning: Flammable. Vapor Harmful. See A1.4.
NOTE 9—The use of copper tubing is not recommended with samples
containing acetylene as this could lead to the formation of potentially
explosive copper acetylide.
7. Sampling
7.1 Samples should be supplied to the laboratory in high
pressure sample cylinders, obtained using the procedures
described in Practice F 307, or similar methods.
8. Preparation of Apparatus
8.1 Silica Gel Column—Dry the silica gel in an oven at
204°C (400°F) for 3 h, cool in a desiccator, and store in
screw-cap bottles. Pour the activated silica gel into a 0.9-m
(3-ft) length of 6.4-mm ( ⁄4-in.) outside diameter copper or
aluminum tubing plugged with glass wool at one end. Tap or
vibrate the tube while adding the silica gel to ensure uniform
packing and plug the top end with glass wool. Shape the
column to fit into the chromatograph.
8.2 Silver Nitrate—b,b8-Oxydipropionitrile—Activated
FIG. 1 Typical Chromatogram for Propylene CarbonColumn—Weigh10gof b,b8-oxydipropionitrileintoa
D2505
TABLE 1 Suggested Composition of a Concentrate of Impurities
brown 125-mL(4-oz) bottle.Add5gof silver nitrate (AgNO )
Used in Preparing Standard Mixtures for Calibration Purposes
crystals. With occasional shaking, dissolve as muchAgNO as
Component Percent
possible, and allow the bottle to stand overnight to ensure
Carbon dioxide 10
saturation. Prepare this solution fresh, as required. Without
Methane 45
disturbing the crystals at the bottom of the bottle, weigh 2.5 g
Ethane 25
of supernatant AgNO solution into a 250-mL beaker and add
3 Propylene 20
50 mL of methanol. While stirring this mixture, slowly add
22.5 g of activated carbon. Place the beaker on a steam bath to
using a similar apparatus as follows: Evacuate the apparatus
evaporate the methanol. When the impregnated activated
and add the components in the order of increasing vapor
carbon appears to be dry, remove the beaker from the steam
pressure; that is, propylene, carbon dioxide, ethane and meth-
bath and finish drying in an oven at 100 to 110°C for 2 h. Plug
ane. Record the increase in pressure on the manometer as each
one end of a 4-ft (1.2-m) length of 6.4-mm ( ⁄4-in.) outside
component is added. Close the reservoir and evacuate the
diameter aluminum or stainless steel tubing with glass wool.
manometer after each addition.
Hold the tubing vertically with the plugged end down and pour
9.1.2 Dilution of Concentrate—Dilute the concentrate with
freshly dried column packing into it, vibrating the column
high-purity ethylene in a ratio of approximately 1:4000. This
during filling to ensure uniform packing. Plug the top end with
canbedonebyaddingthecalculatedamountoftheconcentrate
glass wool and shape the tubing so that it may be mounted
and high purity ethylene to an evacuated cyclinder using the
conveniently in the chromatograph.
gas-blending apparatus (Fig. 2). Use a source of high-pressure,
8.3 Hexamethylphosphoramide Column (HMPA)—Dry the
high-purity ethylene equipped with a needle valve and a
35 to 80-mesh inert support at 204°C (400°F). Weigh 75 g into
pressure gage capable of accurately measuring the pressure of
awide-mouth500-mL(16-oz)bottle.Add15gofHMPAtothe
theblendastheethyleneisaddedtothecylindercontainingthe
inert support and shake and roll the mixture until the support
concentrate.Add the calculated amount of ethylene; warm one
appears to be uniformly wet with the HMPA. Pour the packing
end of the cylinder to ensure mixing of the blend. Allow the
into a 6-m (20-ft) length of 6.4-mm ( ⁄4-in.) outside diameter
temperature to reach equilibrium before recording the final
copper of aluminum tubing plugged at one end with glass
pressure on the cylinder. Prepare at least three calibration
wool. Vibrate the tubing while filling to ensure more uniform
samples containing the compounds to be determined over the
packing. Plug the top end of the column with glass wool and
range of concentration desired in the products to be analyzed.
shape the column to fit into the chromatograph.
8.4 Hexadecane-SqualaneColumn—Dissolve 30 g of hexa- NOTE 11—Precaution: As a safety precaution, use a manifold and
fittings such as valves and gages that will withstand the pressure
decane into approximately 100 mL of acetone.Add 70 g of 80
encountered.
to 100-mesh inert support. Mix thoroughly and pour the
mixture into an open pan for drying. The slurry should be
9.2 Calculation of Composition of Standard Mixtures—
stirred during drying to ensure uniform distribution. When the Calculate the exact ratio of the concentrate dilution with
acetone has evaporated, add a portion of the packing to a 7-m
ethylene by correcting the pressure of the ethylene added for
(25-ft) length of 3.2-mm ( ⁄8-in.) outside diameter nylon tubing
the compressibility of ethylene (Table 2). Multiply the dilution
whichhasbeenpluggedatoneendwithglasswool.Vibratethe
ratio or factor by the percentage of each component present in
column while filling to ensure more uniform packing. Fill the
the original concentrate (Table 1). These calculations give the
column with packing to only 4 m (15 ft) of the length of the
amount of each component that has been added to the
column. Fill the remainder of the column with squalane
high-purityethyleneblendstock.Theactualcompositionofthe
packing prepared in the same manner as the hexadecane
final blend must be ascertained by making corrections for the
packing. Plug the open end of the tubing with glass wool and
impurities present in the high-purity ethylene used for the
shape the column to fit into the chromatograph with the blendstock.Theamountofcorrectionisdeterminedbymaking
hexadecane portion of the column at the front end of the
chromatograph runs on the high-purity ethylene and measuring
column. The column shall be purged under test conditions (no the peak heights of the impurities. These peak heights will be
sample added) until a constant baseline is obtained.
used in adjusting the calibration factors described in 9.3. Since
peak height is very sensitive to changes in conditions, it is
NOTE 10—Columns made with liquid phases listed above were used
extremely important in correlating peak heights obtained in
satisfactorily in cooperative work. Other columns may be used (see 5.3).
making calibrations, calibration adjustments, and final impu-
9. Calibration rity determinations that these values be obtained under the
same GLC column operating conditions in all cases.
9.1 Preparation of Standard Mixtures:
9.3 Determination of Calibration Factors—Chromatograph
9.1.1 PreparationofConcentrate—Prepare a concentrate of
the standard blend and the high-purity ethylene blend stock by
the impurities expected to be encountered. A certified calibra-
each of the procedures given in Section 10.
tion blend containing the expected impurities can be obtained
9.3.1 Calculate calibration factors for carbon dioxide, meth-
and used as the concentrate. An example of a satisfactory
ane, ethane, propylene, and heavier hydrocarbons as follows:
concentrate is given in Table 1. The concentrate can be
prepared using the gas blending manifold as shown in Fig. 2 or F 5C/ S 2B! (1)
~
D2505
TABLE 2 Supercompressibility of Ethylene
NOTE 1—The trace component, A, in parts per million volume of finished blend, is determined as follows:
A 5 @~1
...