ASTM D5808-95

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 5808 – 95
Standard Test Method for
Determining Organic Chloride in Aromatic Hydrocarbons
and Related Chemicals by Microcoulometry
This standard is issued under the fixed designation D 5808; 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 OSHA Regulations—29CFR paragraphs 1910.1000 and
1910.1200
1.1 This test method covers the organic chlorides in aro-
matic hydrocarbons, their derivatives, and related chemicals.
3. Terminology
1.2 This test method is applicable to samples with chloride
3.1 Definitions:
concentrations from 1 to 25 mg/kg.
3.1.1 dehydration tube—a chamber containing concentrated
1.3 This test method is preferred over Test Method D 5194
sulfuric acid that scrubs the effluent gases from combustion to
for products, such as styrene, that are polymerized by the
remove water vapor.
sodium biphenyl reagent.
3.1.2 oxidative pyrolysis—a process in which a sample is
1.4 The following applies to all specified limits in this
combusted in an oxygen-rich atmosphere at high temperature
standard: for purposes of determining conformance with this
to break down the components of the sample into elemental
standard, an observed value or a calculated value shall be
oxides.
rounded off “to the nearest unit” in the last right-hand digit
3.1.3 recovery factor—an indication of the efficiency of the
used in expressing the specification limit, in accordance with
measurement computed by dividing the measured value of a
the rounding-off method of Practice E 29.
standard by its theoretical value.
1.5 This standard does not purport to address all of the
3.1.4 reference sensor pair—detects changes in silver ion
safety concerns, if any, associated with its use. It is the
concentration.
responsibility of the user of this standard to establish appro-
3.1.5 test titration—a process that allows the coulometer to
priate safety and health practices and determine the applica-
set the endpoint and gain values to be used for sample analysis.
bility of regulatory limitations prior to use. For specific hazard
3.1.6 titration parameters—various instrumental conditions
statements, see Note 2 and Section 9.
that can be changed for different types of analysis.
2. Referenced Documents 3.1.7 working electrode (generator electrode)—an electrode
consisting of an anode and a cathode separated by a salt bridge;
2.1 ASTM Standards:
maintains a constant silver ion concentration.
D 1193 Specification for Reagent Water
D 3437 Practice for Sampling and Handling Liquid Cyclic
4. Summary of Test Method
Products
4.1 A liquid specimen is injected into a combustion tube
D 5194 Test Method for Trace Chloride in Liquid Aromatic
3 maintained at 900°C having a flowing stream of 50 % oxygen
Hydrocarbons
and 50 % argon carrier gas. Oxidative pyrolysis converts the
E 29 Practice for Using Significant Digits in Test Data to
4 organic halides to hydrogen halides that then flow into a
Determine Conformance with Specifications
titration cell where it reacts with silver ions present in the
2.2 Other Document:
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
This test method is under the jurisdiction of ASTM Committee D16 on
prove harmful to equipment and reactions in processes involv-
Aromatic Hydrocarbons and Related Chemicals is the direct responsibility of
Subcommittee D16.04 on Instrumental Analysis. ing hydrocarbons.
Current edition approved Oct. 10, 1995. Published December 1995.
Annual Book of ASTM Standards, Vol 11.01.
3 5
Annual Book of ASTM Standards, Vol 06.04. Available from Superintendent of Documents, U.S. Government Printing
Annual Book of ASTM Standards, Vol 14.02. Office, Washington, DC 20402.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5808
5.2 Maximum chloride levels are often specified for process 7.7 Dehydration Tube, positioned at the end of the pyrolysis
streams and for hydrocarbon products. tube so that effluent gases are bubbled through a sulfuric acid
5.3 Organic chloride species are potentially damaging to solution, and water vapor is subsequently trapped, while all
refinery processes. Hydrochloric acid can be produced in other gases are allowed to flow into the titration cell.
hydrotreating or reforming reactors and this acid accumulates 7.8 Gas-Tight Sampling Syringe, having a 50 μl capacity,
in condensing regions of the refinery. capable of accurately delivering 10 to 40 μl of sample.
7.9 Quartz Boats.
6. Interferences
8. Reagents and Materials
6.1 Both nitrogen and sulfur interfere at concentrations
greater than approximately 0.1 %. 8.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
NOTE 1—To ensure reliable detectability, all sources of chloride con-
all reagents shall conform to the specifications of the Commit-
tamination must be eliminated.
tee on Analytical Reagents of the American Chemical Society,
6.2 Bromides and iodides, if present, will be calculated as 7
where such specifications are available. Other grades may be
chlorides. However, fluorides are not detected by this test
used, provided that the reagent is of sufficiently high purity to
method.
permit its use without lessening the accuracy of the determi-
6.3 Organic chloride values of samples containing inorganic
nation.
chlorides will be biased high due to partial recovery of
8.2 Purity of Water—Unless otherwise indicated, references
inorganic species during combustion. Interference from inor-
to water shall be understood to mean reagent water conforming
ganic species can be reduced by water washing the sample
to Specification D 1193, Type II or III.
before analysis. This does not apply to water soluble samples.
8.3 Acetic Acid (sp gr 1.05)—Glacial acetic acid
6 (CH COOH).
7. Apparatus
8.4 Argon or Helium, 99.9 % minimum purity required as
7.1 Pyrolysis Furnace, which can maintain a temperature
carrier gas.
sufficient to pyrolyze the organic matrix and convert all
8.5 Sodium Acetate, anhydrous, (NaCH CO ), fine granular.
3 2
chlorine present in the sample to hydrogen chloride.
8.6 Cell Electrolyte Solution—Dissolve 1.35 g sodium ac-
7.2 Pyrolysis Tube, made of quartz and constructed so that
etate (NaCH CO ) in 850 mL of acetic acid (CH COOH), and
3 2 3
when a sample is volatilized in the front of the furnace, it is
dilute to 1000 mL with water.
swept into the pyrolysis zone by an inert gas, where it
NOTE 3—Bulk quantities of the electrolyte should be stored in a dark
combusts when in the presence of oxygen. The inlet end of the
bottle or in a dark place and be prepared fresh at least every two weeks.
tube must have a sample inlet port with a septum through
which the sample can be injected by syringe. The inlet end
8.7 Oxygen, 99.6 % minimum purity is required as the
must also have side arms for the introduction of oxygen and reactant gas.
inert carrier gas. The pyrolysis tube must be of ample volume, 8.8 Gas Regulators, two-stage gas regulators must be used
so that complete pyrolysis of the sample is ensured. for the reactant and carrier gas.
7.3 Titration Cell, containing a reference electrode, a work- 8.9 Potassium Nitrate (KNO ), fine granular.
ing electrode, and a silver sensor electrode, as well as a 8.10 Potassium Chloride (KCl), fine granular.
magnetic stirrer. An inlet from the pyrolysis tube is also 8.11 Working Electrode Solution (10 % KNO )—Dissolve
required. 50 g potassium nitrate (KNO ) in 500 mL of distilled water.
8.12 Inner Chamber Reference Electrode Solution (1 M
NOTE 2—Caution: Excessive stirring speed will decouple the stirring
KCl)—Dissolve 7.46 g potassium chloride (KCl) in 100 mL of
bar, and cause it to rise in the titration cell and possibly damage the
distilled water.
electrodes. A slight vortex in the cell will be adequate.
8.13 Outer Chamber Reference Electrode Solution (1 M
7.4 Microcoulometer, capable of measuring the potential of
KNO )—Dissolve 10.1 g potassium nitrate (KNO ) in 100 mL
3 3
the sensing-reference electrode pair, and comparing this poten-
of distilled water.
tial with a bias potential, and amplifying the difference to the
8.14 Sodium Chloride (NaCl), fine granular.
working electrode pair to generate a current. The microcou-
8.15 Sulfuric Acid, (sp gr 1.84), (H SO ) concentrated.
2 4
lometer output voltage signal should be proportional to the
8.16 2,4,6-Trichlorophenol (TCP) (C H OCl ), fine granu-
6 3 3
generating current.
lar.
7.5 Automatic Boat Drive, having variable stops, such that
8.17 Methanol (MeOH) (CH OH), 99.9 % minimum purity.
the sample boat may be driven into the furnace, and stopped at
8.18 Chloride Standard Stock Solution—Weigh accurately
various points as it enters the furnace.
0.1 g of 2,4,6-Trichlorophenol to 0.1 mg. Transfer to a 500-mL
7.6 Controller, with connections for the reference, working,
volumetric flask. Dilute to the mark with methanol.
and sensor electrodes. The controller is used for setting of
operating parameters and integration of data.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Microcoulometer such as the TOX-10( and TOX-10, manufactured by listed by the American Chemical Society, see Analar Standards for Laboratory
Mitsubishi Chemical Corporation, and available through Cosa Instruments, 55 Oak Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Street, Norwood, NJ 07648, or equivalent instrument, has been found satisfactory and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
for this pur
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