Значение и использование

This test method is suitable for setting specifications on the materials referenced in 1.2 and for use as an internal quality control tool where isopropylbenzene is produced or is used in a manufacturing process. It may also be used in development or research work involving isopropylbenzene.

This test method is useful in determining the purity of isopropylbenzene with normal impurities present. If extremely high boiling or unusual impurities are present in the isopropylbenzene, this test method would not necessarily detect them and the purity calculation would be erroneous.

Cumene hydroperoxide, if present, will yield thermal decomposition products, primarily AP and DMPC as stated in 4.1, that will elute in the chromatogram thereby giving incorrect results unless they are excluded as indicated in 4.1. It is also possible to get erroneous results for trace alpha-methylstyrene present in isopropylbenzene if the inlet has become unduly contaminated with non-volatile foreign substances.

The nonaromatic hydrocarbons commonly present from the isopropylbenzene manufacturing process, particularly a non-zeolitic one, will interfere with the determination of xylenes (if present).

Область применения

1.1 This test method covers the determination of the purity of isopropylbenzene (cumene) by gas chromatography. Calibration of the gas chromatography system is done by the external standard calibration technique.

1.2 This test method has been found applicable to the measurement of impurities such as nonaromatic hydrocarbons, benzene, toluene, ethylbenzene, phenol, cymenes, t-butylbenzene, n-butylbenzene, n-propylbenzene, alpha-methylstyrene, sec-butylbenzene, and diisopropylbenzenes, which are impurities that can be found in isopropylbenzene. The latter impurities can be analyzed over a range of 1 mg/kg to 500 mg/kg by this method (see Table 1). The limit of detection for these impurities is summarized in Table 1 as well.

1.3 In determining the conformance of the test results using this method to applicable specifications, results shall be rounded off in accordance with the rounding-off method of Practice E 29.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 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 8.

TABLE 1 Summary of Precision Data (mg/kg)

CompoundRepeatabilityReproducibilityRange
Studied Benzene1.004+0.006*Benzene0.924+0.158*Benzene1.0–295 Toluene0.644+0.009*Toluene1.505+0.069*Toluene0.2–260 Ethylbenzene (EB)1.249+0.022*EB2.534+0.230*EB5–370 n-Propylbenzene (NPB)-0.369+0.015*NPB-6.793+0.214*NPB180–465 Phenol (PHE)1.926+.0095*PHE3.718+0.207*PHE1–225 alpha-methylstyrene(AMS)1.368+0.057*AMS21.181+0.976*AMS6–305 tert-Butylbenzene(TBB)1.666+0.011*TBB4.126+0.086*TBB2–250 sec-Butylbenzene(SBB)0.635+0.010*SBB0.891+0.090*SBB2–245 m-Cymene0.618+0.011*m-Cymene1.811+0.181*m-Cymene5–240 o-Cymene0.498+0.012*o-Cymene1.951+0.156*o-Cymene1–160 p-Cymene0.485+0.019*p-Cymene1.618+0.097*p-Cymene2–270 n-Butylbenzene(NBB)0.445+0.030*NBB2.600+0.045*NBB0.3–265 1,3-diisopropylbenzene(13DIPB)0.727+0.010*13DIPB1.570+0.720*13DIPB1–210 1,4-diisopropylbenzene(14DIPB)0.435+0.013*14DIPB1.112+0.040*14DIPB1–285 NonAromatics(NA)0.441+0.242*NA1.663+0.306*NA5–95