ASTM D3760-98
(Test Method)Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography
Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography
SCOPE
1.1 This test method covers the determination of the purity of isopropylbenzene (cumene) by gas chromatography.
1.2 This test method has been found applicable to the measurement of impurities such as nonaromatic hydrocarbons, benzene, ethylbenzene, t-butylbenzene, n-propylbenzene, alpha-methylstyrene, sec-butylbenzene, and diisopropylbenzene, which are common to the manufacturing process of isopropylbenzene. Limit of detection for these impurities is 10 mg/kg (see 5.1).
1.3 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29.
1.4 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. For specific hazard statements, see Section 7.
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Designation: D 3760 – 98
Standard Test Method for
Analysis of Isopropylbenzene (Cumene) by Gas
Chromatography
This standard is issued under the fixed designation D 3760; 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 3. Summary of Test Method
1.1 This test method covers the determination of the purity 3.1 A known amount of internal standard is added to a
of isopropylbenzene (cumene) by gas chromatography. sample of isopropylbenzene. The prepared sample is mixed
1.2 This test method has been found applicable to the and analyzed by a gas chromatograph equipped with a flame
measurement of impurities such as nonaromatic hydrocarbons, ionization detector (FID). The peak area of each impurity and
benzene, ethylbenzene, t-butylbenzene, n-propylbenzene, the internal standard is measured and the amount of each
alpha-methylstyrene, sec-butylbenzene, and diisopropylben- impurity is calculated from the ratio of the peak area of the
zene, which are common to the manufacturing process of internal standard versus the peak area of the impurity. Purity by
isopropylbenzene. Limit of detection for these impurities is 10 GC (the isopropylbenzene content) is calculated by subtracting
mg/kg (see 5.1). the sum of the impurities found from 100.00. Results are
1.3 The following applies to all specified limits in this reported in weight percent.
standard: for purposes of determining conformance with this
4. Significance and Use
standard, an observed value or a calculated value shall be
rounded off “to the nearest unit” in the last right-hand digit 4.1 This test method is suitable for setting specifications on
the materials referenced in 1.2 and for use as an internal quality
used in expressing the specification limit, in accordance with
the rounding-off method of Practice E 29. control tool where isopropylbenzene is produced or is used in
a manufacturing process. It may also be used in development
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the or research work involving isopropylbenzene.
4.2 This test method is useful in determining the purity of
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- isopropylbenzene with normal impurities present including
diisopropylbenzenes. If extremely high boiling or unusual
bility of regulatory limitations prior to use. For specific hazard
statements, see Section 7. impurities are present in the isopropylbenzene, this test method
would not necessarily detect them and the purity calculation
2. Referenced Documents
would be erroneous.
2.1 ASTM Standards: 4.3 Cumene hydroperoxide, if present, will yield decompo-
D 3437 Practice for Sampling and Handling Liquid Cyclic sition products that will elute in the chromatogram thereby
Products giving incorrect results.
E 29 Practice for Using Significant Digits in Test Data to 4.4 The nonaromatic hydrocarbons commonly present from
Determine Conformance with Specifications the isopropylbenzene manufacturing process will interfere with
E 260 Practice for Packed Gas Chromatography the determination of benzene when Column A in Table 1 is
E 355 Practice for Gas Chromatography Terms and Rela- used.
tionships 4.5 The internal standard must be sufficiently resolved from
2.2 Other Document: any impurity and the isopropylbenzene peak.
OSHA Regulations, 29CFR, paragraphs 1910.1000 and
4 5. Apparatus
1910.1200
5.1 Gas Chromatograph—Any instrument having a flame
ionization detector that can be operated at the conditions given
This test method is under the jurisdiction of ASTM Committee D16 on
in Table 1. The system should have sufficient sensitivity to
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of
Subcommittee D16.0H on Styrene, Ethylbenzene, and C and C Aromatic obtain a minimum peak height response for 10 mg/kg
9 10
Hydrocarbons.
n-butylbenzene of twice the height of the signal background
Current edition approved May 10, 1998. Published August 1998. Originally
e1 noise.
published as D 3760 – 79. Last previous edition D 3760 – 93 .
Annual Book of ASTM Standards, Vol 06.04. 5.2 Columns—The choice of column is based on resolution
Annual Book of ASTM Standards, Vol 14.02.
requirements. Any column may be used that is capable of
Available from Superintendent of Documents, U.S. Government Printing
resolving all significant impurities from isopropylbenzene and
Office, Washington, DC 20402.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 3760
TABLE 1 Instrumental Parameters
conditioning the column into the chromatograph and adjusting
Column A Column B the instrument to the conditions described in Table 1 allowing
sufficient time for the equipment to reach equilibrium. See
Detector Flame Ionization Flame Ionization
Column:
Practices E 260 and E 355 for additional information on gas
Tubing fused silica fused silica
chromatography practices and terminology.
Stationary phase polyethylene glycol methyl silicone
Solid support crosslinked crosslinked
10. Procedure
Film thickness 0.25 μ 0.5 μ
Length, m 50 50
10.1 Into a 100-mL volumetric flask, add 100 μL of nBB to
Diameter, mm 0.32 mm ID 0.32 mm ID
99.90 mL of cumene. Mix well. Assuming a density of 0.856
Temperatures:
for nBB and 0.857 for cumene, the resulting nBB concentration
Injector, °C 275 275
Detector, °C 300 300
will be 0.1000 weight %.
Oven:
10.2 Inject into the gas chromatography an appropriate
Initial, °C 60 35
Time 1, min 10 10 amount of sample as previously determined according to 6.1
Final, °C 175 275
and start the analysis.
Rate, °C/min 10 5
10.3 Obtain a chromatograph and peak integration report.
Time 2, min 10 0
Fig. 1 and Fig. 2 illustrate a typical analysis of cumene for
Carrier gas hydrogen helium
Flow rate, mL/min 1.0 1.0
Columns A and B, respectively.
Split ratio 100:1 100:1
Sample size, μL
...
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