ASTM D4782-91(1997)

Standard Test Method for Palladium in Molecular Sieve Catalyst by Wet Chemistry

SCOPE
1.1 This test method covers the determination of palladium in molecular sieve-containing fresh catalysts with about 0.5 weight % of palladium.
1.2 This standard does not purport to address all of the safety problems, 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.

General Information

• Status: Historical
• Publication Date: 31-Dec-1990
• ICS: 71.040.30 - Chemical reagents
• Technical Committee: D32 - Catalysts
• Drafting Committee: D32.03 - Chemical Composition

Relations

• Replaced By: ASTM D4782-04 - Standard Test Method for Palladium in Molecular Sieve Catalyst by Wet Chemistry
• Effective Date: 01-Apr-2004

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 4782 – 91 (Reapproved 1997)
Standard Test Method for
Palladium in Molecular Sieve Catalyst by Wet Chemistry
This standard is issued under the fixed designation D 4782; 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 4.2 This test method is not intended to cover samples
containing metals other than palladium.
1.1 This test method covers the determination of palladium
in molecular sieve-containing fresh catalysts with about 0.5
5. Apparatus
weight % of palladium.
5.1 pH Meter with Millivolt Scale or automatic recording
1.2 This standard does not purport to address all of the
titrator.
safety concerns, if any, associated with its use. It is the
5.2 Silver-Sulfide Electrode.
responsibility of the user of this standard to establish appro-
5.3 Silver-Silver Chloride Double Junction reference elec-
priate safety and health practices and determine the applica-
trode with 10 % KNO in the outer chamber.
bility of regulatory limitations prior to use.
5.4 Fisher Burner.
2. Referenced Documents 5.5 Low-Temperature Muffle Furnace, 450°C.
5.6 High-Temperature Muffle Furnace, 1000°C.
2.1 ASTM Standards:
5.7 Hot-Plate, with sand bath as a preferred option.
D 1193 Specification for Reagent Water
5.8 Magnetic Stirrer and TFE-Fluorocarbon-Coated Stir-
E 177 Practice for Use of the Terms Precision and Bias in
ring Bars.
ASTM Test Methods
5.9 Burets, 25-mL, with 0.1-mL graduations or an equiva-
E 456 Terminology Relating to Quality and Statistics
lent.
E 691 Practice for Conducting an Interlaboratory Study to
5.10 Volumetric Flasks, 1000-mL.
Determine the Precision of a Test Method
5.11 High-Silica Beakers, 400-mL, with throw-away boro-
3. Summary of Test Method
silicate beakers as an option. Alternatively, a petri dish can be
used for the fusion step, with polypropylene beakers being
3.1 The test sample is treated with hydrofluoric acid and
used thereafter.
evaporated to dryness to remove silica; the residue is fused
5.12 Watch Glasses, preferably ribbed, 87 mm.
with potassium pyrosulfate, and the cooled melt is dissolved in
5.13 Analytical Balance, capable of weighing to nearest 0.1
4% H SO . A measured excess of 0.01 N potassium iodide
2 4
mg.
(KI) is added to precipitate palladium as palladium iodide
5.14 Weighing Papers.
(PdI ). The precipitate is filtered and washed, and a small
5.15 Porcelain Crucibles, 10-mL.
amount of sodium sulfite is added to the filtrate to reduce any
5.16 Graduated Cylinders, 5-mL, 10-mL, 25-mL, 100-mL.
free iodine to iodide. The excess iodide is titrated with 0.01 N
5.17 Filter Paper, Whatman No. 40, 11 cm.
AgNO potentiometrically, using a silver electrode versus a
5.18 Funnel, filter.
calomel electrode. A second sample taken at the same time is
5.19 Desiccator.
used to determine loss on ignition.
5.20 Crucible Cover, porcelain.
4. Significance and Use
6. Reagents and Materials
4.1 This test method provides a means of determining the
6.1 Purity of Reagents—Reagent grade chemicals shall be
palladium content in fresh catalysts containing molecular
used in all tests. Unless otherwise indicated, it is intended that
sieves.
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society,
This test method is under the jurisdiction of ASTM Committee D-32 on
Catalysts and is the direct responsibility of Subcommittee D32.03 on Chemical
Analysis. Example: Corning Model 7 or equivalent.
Current edition approved July 15, 1991. Published September 1991. Originally Example: Orion No. 94-16 or equivalent.
published as D 4782 – 88. Last previous edition D 4782 – 90. Example: Orion No. 90-02-00 or equivalent.
2 7
Annual Book of ASTM Standards, Vol 11.01. Example: Fisher Cat. No. 09-898-12B or equivalent.
3 8
Annual Book of ASTM Standards, Vol 14.02. Alundum or other suitable materials may be used.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 4782
where such specifications are available. Other grades may be ~I 2 F!
Weight % LOI 5 3 100 (1)
~I!
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
where:
accuracy of the determination.
I = initial sample weight, and
6.2 Purity of Water—Unless otherwise indicated, references
F = final sample weight.
to water shall be understood to mean reagent water as defined
7.3 Preparation of Test Sample for Titration:
by Specification D 1193.
7.3.1 Cautiously add about 3 mL water to the high-silica
6.3 Desiccant Molecular Sieve, type 4A.
beaker to disperse the test sample.
6.4 Filter Paper Pulp.
7.3.2 Add 12 mL hydrofluoric acid (HF) to effect dissolu-
6.5 Hydrofluoric acid (HF), 48 %.
tion and evaporate to dryness on the cooler areas of the sand
6.6 Potassium Iodide Solution, 0.01 N—Dissolve 1.66 g of
bath to remove silicon dioxide (SiO ).
potassium iodide (KI) in distilled water, dilute to 1000 mL, and
7.3.3 Promptly remove the beaker from the sand bath, cover
mix well.
residue with9gof potassium pyrosulfate, and heat gently over
6.7 Potassium Pyrosulfate (K S O ).
2 2 8
a Fisher burner until all excess hydrofluoric acid (HF) is driven
6.8 Silver Nitrate Solution, 0.01000 N—Dissolve 1.6989 g
off. Heat over flame until clear fusion results. Tilt or swirl the
of silver nitrate (AgNO ) in distilled water, dilute to 1000 mL,
beaker on cooling to prevent breakage.
and mix well.
7.3.4 Add 20 mL of 48 % H SO and 15 mL of distilled
2 4
NOTE 1—Caution: The preparation of the AgNO standard solution is
water, cover and heat to boiling on sand bath to dissolve melt.
a critical step. If any traces of chloride, organic matter or reducing agents
Remove from the sand bath, dilute to 200 mL with boiling
are present in the water, more AgNO will be used in the back-titration and
distilled water, and cool.
the final result will be low. Standardization is recommended.
7.3.5 Place beaker on a magnetic stirrer, insert stirring bar
6.9 Sodium Sulfite Solution, 10 % Dissolve 10 g of anhy- and add a small wad of paper pulp. Add 5 mL of HF and stir
drous sodium sulfite (Na SO ) in 100 mL of dis
...