ASTM D1157-23

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D1157 − 91 (Reapproved 2019) D1157 − 23
Standard Test Method for
1,2
Total Inhibitor Content (TBC) of Light Hydrocarbons
This standard is issued under the fixed designation D1157; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This test method covers the determination of total p-tertiary-butylcatechol inhibitor added to polymerization and recycle
grades of butadiene or to other C hydrocarbon mixtures containing no phenolic material other than catechol or no oxidized
phenolic material other than that derived from oxidation of catechol. In general, all phenols and their quinone oxidation products
are included in the calculated catechol content. Small amounts of polymer do not interfere. This test method is applicable over the
range of TBC from 50 mg ⁄kg to 500 mg ⁄kg.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.3.1 The user is advised to obtain LPG safety training for the safe operation of this test method procedure and related activities.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1265 Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method
3. Summary of Test Method
3.1 The catechol is separated from the butadiene by evaporation. The residue is dissolved in water and an excess of ferric chloride
is added. The intensity of the yellow-colored complex is compared in a photoelectric colorimeter with that produced by known
concentrations of the catechol.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of Subcommittee
D02.D0.04 on C4 and C5 Hydrocarbons.
Current edition approved Dec. 1, 2019March 1, 2023. Published December 2019June 2023. Originally approved in 1951. Last previous edition approved in 20142019 as
D1157 – 91 (2014).(2019). DOI: 10.1520/D1157-91R19.10.1520/D1157-23.
This test method was derived from the method developed and cooperatively tested by the Butadiene Producers’ Committee on Specifications and Methods of Analysis
of the Office of Rubber Reserve, which appears in the Butadiene Laboratory Manual as Method 2.1.9.1.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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D1157 − 23
4. Significance and Use
4.1 p-tertiary-butylcatechol is commonly added to commercial butadiene in amounts of 50 mg ⁄kg to 250 mg ⁄kg as an oxidation
inhibitor. This test method is suitable for use by both producers and users of butadiene within the limitations described in Section
1.
5. Apparatus
5.1 Photometer—A sensitive photoelectric photometer capable of producing light of narrow spectral range that is predominantly
blue (425 nm).
5.2 Graduates, 100 mL.
5.3 Volumetric Flasks, 100 mL; or stoppered graduated mixing cylinder, 100 mL.
5.4 Erlenmeyer Flasks, 250 mL.
5.5 Funnels, 75 mm diameter.
5.6 Pipet, 5 mL.
6. Reagents
6.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
6.2 Purity of Water—References to water shall be understood to mean distilled water.
6.3 Ferric Chloride, Standard Solution— Dissolve 20.0 g of ferric chloride (FeCl ·6H O) in ethanol (95 %). Add 9.2 mL of HCl
3 2
(sp gr 1.19), and then dilute with ethanol (95 %) to 1000 mL in a volumetric flask.
6.4 p-Tertiary-Butylcatechol, Standard—(Warning—Potentially hazardous. May cause skin irritation or burns; can be absorbed
through the skin. May be harmful or fatal if swallowed. Avoid contact with eyes; may burn and impair vision. May be harmful
to respiratory system. May produce quinones and flammable butylenes on decomposition. Use with adequate ventilation. Store in
flammable liquids storage area.) Dissolve 0.63 g of p-tertiary-butylcatechol (95 % minimum purity) in 10 mL of ethanol (95 %)
and dilute with water to 100 mL in a volumetric flask. When used in place of 100 mL (63 g) of sample, consider 1.00 mL of this
solution to be equivalent to 100 ppm of catechol. This solution is not stable and should be prepared as needed.
7. Sampling
7.1 Supply samples to the laboratory in high-pressure sample cylinders. Use the procedures described in Practice D1265 or similar
methods.
8. Calibration and Standardization
8.1 Preparation of Standard Solutions—Prepare a standardization curve showing the relation between the absorbance and the
catechol content as follows: Make
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