ASTM D4864-90(2000)e1
(Test Method)Standard Test Method for Determination of Traces of Methanol in Propylene Concentrates by Gas Chromatography
Standard Test Method for Determination of Traces of Methanol in Propylene Concentrates by Gas Chromatography
SCOPE
1.1 This test method covers the determination of methanol in propylene concentrates in the range of approximately 4 to 40 mg/kg (parts-per-million by weight).
1.2 The values stated in acceptable SI units are to be regarded as the standard.
Note 1--There is no direct acceptable SI equivalent for screw threads.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in 11.1.1 and 12.11.
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An American National Standard
e1
Designation:D4864–90(Reapproved 2000)
Standard Test Method for
Determination of Traces of Methanol in Propylene
Concentrates by Gas Chromatography
This standard is issued under the fixed designation D 4864; 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.
This standard has been approved for use by agencies of the Department of Defense.
e NOTE—Warning notes were placed in the text editorially in November 2000.
1. Scope 4. Summary of Test Method
1.1 This test method covers the determination of methanol 4.1 A known weight of water is pressured into a sample
inpropyleneconcentratesintherangeofapproximately4to40 cylinder containing a known amount of liquified propylene.
mg/kg (parts-per-million by weight). The contents in the cylinder are shaken and the water/methanol
1.2 The values stated in acceptable SI units are to be phase is withdrawn. A reproducible volume of the extract is
regarded as the standard. then injected into a gas chromatograph (GC) equipped with
either a thermal conductivity or a flame ionization detector.
NOTE 1—There is no direct acceptable SI equivalent for screw threads.
The methanol concentration is calculated from the area of the
1.3 This standard does not purport to address all of the
methanolpeakusingcalibrationandextractionfactorsobtained
safety concerns, if any, associated with its use. It is the
from synthetic blends of known methanol content.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 5. Significance and Use
bility of regulatory limitations prior to use. Specific hazard
5.1 Methanol is a common impurity in propylene. It can
statements are given in 11.1.1 and 12.11.
have a deleterious effect on various processes that use propy-
lene as a feedstock.
2. Referenced Documents
2.1 ASTM Standards: 6. Interferences
D 4307 Practice for Preparation of Liquid Blends for Use as
6.1 There are no known interferences using the GC columns
Analytical Standards
referenced in this test method. However, any water-soluble
E 260 Practice for Packed Column Gas Chromatography
component that co-elutes with methanol on any other GC
column used would interfere.
3. Terminology
3.1 Definitions: 7. Apparatus
3.1.1 propylene concentrate—concentrate containing more
7.1 Gas Chromatograph—Any GC equipped with either
than 90 % propylene.
flame ionization or thermal conductivity detectors with an
3.2 Definitions of Terms Specific to This Standard:
overall sensitivity sufficient to detect at least 4 mg/kg of
3.2.1 outage tube—a length of 6.35-mm ( ⁄4 in.) outside
methanol.
diameter SS tubing normally attached to the inside end of a
7.2 Column—AnyGCcolumnthatseparatesmethanolfrom
valve used on a pressure sampling cylinder. It is used to
water, other alcohols, and any co-extracted hydrocarbons.
facilitate removal of a set quantity of liquified sample to
NOTE 2—See Table 1 for a suitable list of columns and Fig. 1 and Fig.
prevent overpressuring the cylinder.
2 for examples of chromatograms.Also, refer to Practice E 260 for typical
instructions in preparing such columns. Alternatively, columns can be
purchased from commercial sources.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
7.3 Data Handling System—Any commercially available
D02.D0.03 on C4 Test Methods.
GC integrator or GC computer system capable of accurately
Current edition approved Sept. 28, 1990. Published December 1990. Originally
integrating the area of the methanol peak is satisfactory.
published as D 4864 – 88. Last previous edition D 4864 – 88.
Annual Book of ASTM Standards, Vol 05.02.
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4864
A
TABLE 1 Suitable Gas Chromatographic Columns and Temperatures
Column Oven Temperature,°
Column Size, m 3 mm Tubing Type Packing Coating, µm Thickness
Number C
1 1.22 3 6.35 OD SS 15 % Carowax 1540 on 60/80 . 90
Chromosorb W AW
2 3.05 3 4.76 OD SS 80/100 mesh Porapak QS . 100
3 3.05 3 6.35 OD Cu 10 % Carbowax 1540 on . 120
30/60 mesh Chromosorb T
4 6.10 3 6.35 OD Cu 10 % Carbowax 1540 on . 120
30/60 mesh Chromosorb T
5 1.83 3 2 ID glass 10 % Carbowax 20 M on 80/ . 70
100 Chromosorb W AW
615 3 0.53 ID fused silica . J&W DB-5, 1.5 70 to 120 at 2°/min
A
These six columns have been tested cooperatively and have been found suitable for use with this test method.
NOTE 1—Column used: No. 4 of Table 1; detector: thermal conductiv-
ity.
FIG. 2 Chromatogram of Water/Methanol/Propylene Extract
1 1
7.7 Plug Valve, ⁄4-in. male NPT or optionally, ⁄4-in. male
NPTto 6.35 mm outside diameter ( ⁄4 in.) tubing. (See Note 3.)
7.8 Shut-off Valves, ⁄4-in. male NPT to 6.35 mm outside
diameter ( ⁄4 in.) tubing.
1 1
7.9 RegulatingValves, ⁄4-in.maleNPTand ⁄4-in.maleNPT
to ⁄4-in. female NPT.
7.10 Hex Nipple, SS, ⁄4-in. male NPT by 102 mm (4 in.)
long.
7.11 Hex Coupling, SS, ⁄4-in. female NPT by 30 mm (1.2
in.) long.
7.12 Brass Cap, ⁄4-in. NPT or optionally, a tube fitting nut,
6.35 mm outside diameter ( ⁄4in.). (See Note 3.)
7.13 Septum, TFE-fluorocarbon lined, 11-mm diameter.
7.14 Syringes, 10 and 25 µL.
NOTE 1—Column used: No. 5 of Table 1; detector: flame ionization.
FIG. 1 Chromatograms of Water/Methanol Standard and Water/
A
Methanol/Propylene Extract 8. Reagents and Materials
8.1 Methanol, reagent grade or better.
8.2 Propylene,92+ %puritycontaining<0.2mg/kg(ppmw)
7.4 Recorder—A strip-chart recorder with a full scale re-
methanol.
sponseof2sorlessandamaximumnoiserateofplusorminus
0.3 % full scale. 9. Sampling
7.5 Sample Cylinders, 300-mL capacity, stainless steel,
9.1 The propylene sample shall be in the liquified state and
Type DOT 3E (12409 kPa ((1800 psig)) working pressure).
be representative of the material in the storage tank or process
7.6 Balances—Any types capable of weighing a 300-mL line. Also, for purposes of this method as well as for safety
sample cylinder and contents accurately to 0.1 g and a 25-mL considerations, there must be a vapor space of about 15 % in
volumetric flask and contents accurately to 0.0001 g. the sampling container. It is recommended that sampling
D4864
cylinders of the type listed in Section 7 be used. They can be
equipped with an outage tube to effect the 15 % vapor space
requirement.
10. Preparation of Apparatus
10.1 Prepare a water injection device. A suitable device is
shown in Fig. 3. However, any other device that will deliver
from 8 to 15 g of water can be used.
10.2 Prepare a 300-mL sample cylinder for use as a metha-
nol cylinder, as shown in Fig. 4. (This cylinder must not
contain an outage tube.) Drilla3to4mm (approximately ⁄8
in.)holeina ⁄4-in.NPTbrasscap,insertan11-mmseptuminto
it, and screw it onto the plug valve.
NOTE 3—As an alternative, the cylinder can be equipped with ⁄4-in.
male NPT to a 6.35-mm ( ⁄4-in.) outside diameter tubing plug valve. Then
a 6.35-mm tube fitting nut can be used with the septum, thus avoiding the
necessity of drilling a brass cap.
FIG. 4 Methanol Cylinder Extraction Factor Determination
10.3 Set up the chromatograph in accordance with the
manufacturer’s recommendations. Install the analytical column
and adjust the gas flows and temperatures so that methanol will
elute at the desired time. Condition the column at operating
conditions until a stable baseline is recorded at the required
sensitivity.
11. Calibration
11.1 Determination of Methanol Response Factor—Prepare
several aqueous solutions of methanol in the same concentra-
tion range as expected for samples to be analyzed.
NOTE 4—Thisshouldbeapproximately40to400mg/kg(ppmw)onthe
basis of propylene sample sizes of 100 to 120 g, water extract volumes of
about 10 g, and methanol concentrations in the propylene of 4 to 40
mg/kg.
11.1.1 Methanol Stock Solution—Weigh an empty volumet-
ric flask of at least 25 mLcapacity to the nearest 0.0001 g.Add
20 mLof deionized water to the flask and reweigh. Finally, add
2 mL of methanol and again reweigh. Stopper and mix
thoroughly. This should contain approximately 73 000 mg/kg
(ppm by weight) of methanol. Calculate the exact concentra-
tion from the actual weights used. (Warning—Methanol is
toxic and flammable. Use with adequate ventilation and keep
FIG. 3 Water Injection Assembly away from ignition sources.)
D4864
NOTE 5—Refer to Practice D 4307 for additional information in pre-
11.2.6 Cool the evacuated cylinder to about 20°C below the
paring this solution and the calibration solution in 11.1.2.
temperature of the propylene cylinder.
11.2.7 As shown in Fig. 5, connect the cylinder containing
11.1.2 Methanol Calibration Solutions
...
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