ASTM D5808-23

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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: D5808 − 20 D5808 − 23
Standard Test Method for
Determining Chloride in Aromatic Hydrocarbons and
Related Chemicals by Microcoulometry
This standard is issued under the fixed designation D5808; 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*
1.1 This test method covers the determination of organic chloride in aromatic hydrocarbons, their derivatives, and related
chemicals.
1.2 This test method is applicable to samples with chloride concentrations to 25 mg/kg. The limit of detection (LOD) is 0.2 mg/kg
and the limit of quantitation (LOQ) is 0.7 mg/kg. With careful analytical technique or the measurement of replicates, or both, this
method can be used to successfully analyze concentrations below the LOD.
NOTE 1—The maximum is the highest concentration from the interlaboratory study and the LOD and LOQ were calculated from Performance Testing
Program (PTP) data. See Table 1.
1.3 This test method is preferred over Test Method D5194 for products, such as styrene, that are polymerized by the sodium
biphenyl reagent.
1.4 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 E29.
1.5 Organic chloride values of samples containing inorganic chlorides will be biased high due to partial recovery of inorganic
species during combustion. Interference from inorganic species can be reduced by water washing the sample before analysis. This
does not apply to water soluble samples.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 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. For specific hazard statements, see 7.3 and Section 9.
1.8 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.
This test method is under the jurisdiction of ASTM Committee D16 on Aromatic, Industrial, Specialty and Related Chemicals is the direct responsibility of Subcommittee
D16.04 on Instrumental Analysis.
Current edition approved Aug. 15, 2020Nov. 1, 2023. Published August 2020November 2023. Originally approved in 1995. Last previous edition approved in 20182020
as D5808 – 18.D5808 – 20. DOI: 10.1520/D5808-20.10.1520/D5808-23.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5808 − 23
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D1555M Test Method for Calculation of Volume and Weight of Industrial Aromatic Hydrocarbons and Cyclohexane [Metric]
D3437 Practice for Sampling and Handling Liquid Cyclic Products
D5194 Test Method for Trace Chloride in Liquid Aromatic Hydrocarbons
D6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
2.2 Other Document:
OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.1200
3. Terminology
3.1 Definitions:
3.1.1 dehydration tube, n—chamber containing concentrated sulfuric acid that scrubs the effluent gases from combustion to
remove water vapor.
3.1.2 oxidative pyrolysis, n—a process in which a sample is combusted in an oxygen-rich atmosphere at high temperature to break
down the components of the sample into elemental oxides.
3.1.3 recovery factor, n—an indication of the efficiency of the measurement computed by dividing the measured value of a
standard by its theoretical value.
3.1.4 reference sensor pair, n—detects changes in silver ion concentration.
3.1.5 test titration, n—a process that allows the coulometer to set the endpoint and gain values to be used for sample analysis.
3.1.6 titration parameters, n—various instrumental conditions that can be changed for different types of analysis.
3.1.7 working electrode (generator electrode), n—an electrode consisting of an anode and a cathode separated by a salt bridge;
maintains a constant silver ion concentration.
4. Summary of Test Method
4.1 A liquid specimen is injected into a combustion tube maintained at 900°C900 °C having a flowing stream of oxygen and argon
carrier gas. Oxidative pyrolysis converts the organic halides to hydrogen halides that then flow into a titration cell where it reacts
with silver ions present in the electrolyte. The silver ion thus consumed is coulometrically replaced and the total electrical work
to replace it is a measure of the organic halides in the specimen injected (see Annex A1).
5. Significance and Use
5.1 Organic as well as inorganic chlorine compounds can prove harmful to equipment and reactions in processes involving
hydrocarbons.
5.2 Maximum chloride levels are often specified for process streams and for hydrocarbon products.
5.3 Organic chloride species are potentially damaging to refinery processes. Hydrochloric acid can be produced in hydrotreating
or reforming reactors and this acid accumulates in condensing regions of the refinery.
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.
Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
www.access.gpo.gov.
D5808 − 23
6. Interferences
6.1 Both nitrogen and sulfur interfere at concentrations greater than approximately 0.1 %.
NOTE 2—To ensure reliable detectability, all sources of chloride contamination must be eliminated.
6.2 Bromides and iodides, if present, will be calculated as chlorides. However, fluorides are not detected by this test method.
6.3 Organic chloride values of samples containing inorganic chlorides will be biased high due to partial recovery of inorganic
species during combustion. Interference from inorganic species can be reduced by water washing the sample before analysis. This
does not apply to water soluble samples.
7. Apparatus
7.1 Pyrolysis Furnace, which can maintain a temperature sufficient to pyrolyze the organic matrix and convert all chlorine present
in the sample to hydrogen chloride.
7.2 Pyrolysis Tube, made of quartz and constructed so that when a sample is volatilized in the front of the furnace, it is swept into
the pyrolysis zone by an inert gas, where it combusts when in the presence of oxygen. The inlet end of the tube must have a sample
inlet port with a septum through which the sample can be injected by syringe. The inlet end must also have side arms for the
introduction of oxygen and inert carrier gas. The pyrolysis tube must be of ample volume, so that complete pyrolysis of the sample
is ensured.
7.3 Titration Cell, containing a reference and sensor pair of electrodes and a generator anode/cathode pair of electrodes to maintain
constant chloride ion concentration. An inlet from the pyrolysis tube and magnetic stirring is also required. (Warning—Excessive
stirring speed will decouple the stirring bar and cause it to rise in the titration cell and possibly damage the electrodes. A slight
vortex in the cell will be adequate.)
7.4 Microcoulometer, capable of measuring the potential of the sensing-reference electrode pair, and comparing this potential with
a bias potential, and amplifying the difference to the working electrode pair to generate a current. The microcoulometer output
voltage signal should be proportional to the generating current.
7.5 Automatic Boat Drive, having variable stops, such that the sample boat may be driven into the furnace, and stopped at various
points as it enters the furnace.
7.6 Controller, with connections for the reference, working, and sensor electrodes. The controller is used for setting of operating
parameters and integration of data.
7.7 Dehydration Tube, positioned at the end of the pyrolysis tube so that effluent gases are bubbled through a sulfuric acid solution,
and water vapor is subsequently trapped, while all other gases are allowed to flow into the titration cell.
7.8 Gas-Tight Sampling Syringe, having a 50 μl capacity, capable of accurately delivering 1010 μl to 40 μl of sample.
7.9 Quartz Boats.
8. Reagents and Materials
8.1 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 that the reagent is of sufficiently high purity to permit its
use without lessening the accuracy of the determination.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference Materials, American Chemical Society, Washington, DC. For
suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and
the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D5808 − 23
8.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Specification D1193, Type II or III.
8.3 Acetic Acid—Glacial acetic acid (CH COOH).
8.4 Argon or Helium, 99.9 % minimum purity required as carrier gas.
8.5 Amidosulfonic Acid (H NSO H), minimum purity 99.3-100.3 %.
2 3
8.6 Sodium Acetate, anhydrous, (NaCH CO ), fine granular.
3 2
8.7 Cell Electrolyte Solution—Dissolve 1.35 g sodium acetate (NaCH CO ) in 850 mL of acetic acid (CH COOH), and dilute to
3 2 3
1000 mL with water or follow manufacturer’s recommendations.
NOTE 3—Bulk quantities of the electrolyte should be stored in a dark bottle or in a dark place and be prepared fresh at least every two weeks.
8.8 Oxygen, 99.6 % minimum purity is required as the reactant gas.
8.9 Gas Regulators, two-stage gas regulators must be used for the reactant and carrier gas.
8.10 Potassium Nitrate (KNO ), fine granular.
8.11 Potassium Chloride (KCl), fine granular.
8.12 Potassium Sulfate (K SO ), crystalline.
2 4
8.13 Working Electrode Solution (10 % KNO )—Dissolve 50 g potassium nitrate (KNO ) in 500 mL of distilled water.
3 3
8.14 Inner Chamber Reference Electrode Solution (1 M KCl)—Dissolve 7.46 g potassium chloride (KCl) in 100 mL of distilled
water.
8.15 Outer Chamber Reference Electrode Solution (1 M KNO )—Dissolve 10.1
...