ASTM D4824-24
(Test Method)Standard Test Method for Determination of Catalyst Acidity by Ammonia Chemisorption
Standard Test Method for Determination of Catalyst Acidity by Ammonia Chemisorption
SIGNIFICANCE AND USE
5.1 This test method can be used to determine the acidity of catalysts and catalyst carriers by ammonia chemisorption for materials specifications, manufacturing control, and research and development in the evaluation of catalysts.
SCOPE
1.1 This test method covers the determination of acidity of catalysts and catalyst carriers by ammonia chemisorption. A volumetric measuring system is used to obtain the amount of chemisorbed ammonia.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered 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.
1.4 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.
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Standards Content (Sample)
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.
Designation: D4824 − 24
Standard Test Method for
Determination of Catalyst Acidity by Ammonia
1
Chemisorption
This standard is issued under the fixed designation D4824; 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.
INTRODUCTION
This test method involves the measurement of total catalyst acidity by chemisorption of ammonia
in a static volumetric system. Acidity is a very important property in determining catalyst activity and
selectivity in many commercial reactions. Zeolite based catalysts used in the petroleum industry for
catalytic cracking are a prime example. This test method describes a simple procedure employing
inexpensive equipment that could readily be assembled in most laboratories.
1. Scope E122 Practice for Calculating Sample Size to Estimate, With
Specified Precision, the Average for a Characteristic of a
1.1 This test method covers the determination of acidity of
Lot or Process
catalysts and catalyst carriers by ammonia chemisorption. A
E691 Practice for Conducting an Interlaboratory Study to
volumetric measuring system is used to obtain the amount of
Determine the Precision of a Test Method
chemisorbed ammonia.
3. Terminology
1.2 The values stated in SI units are to be regarded as
standard. The values given in parentheses after SI units are
3.1 Definitions—See Terminology D3766.
provided for information only and are not considered standard.
3.2 Symbols:
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3
V = calibrated expansion volume, cm .
responsibility of the user of this standard to establish appro-
k
T = temperature of V at initial ammonia pressure, K.
priate safety, health, and environmental practices and deter-
1 k
T = temperature of V at final ammonia pressure, K.
mine the applicability of regulatory limitations prior to use. 2 k
P = initial ammonia pressure, torr.
1
1.4 This international standard was developed in accor-
P = final ammonia pressure, torr.
2
dance with internationally recognized principles on standard-
W = mass of sample, g.
s
ization established in the Decision on Principles for the
W = tare of sample tube, g.
1
Development of International Standards, Guides and Recom-
W = sample mass plus tare of tube, g.
2
mendations issued by the World Trade Organization Technical
P = initial ammonia pressure corrected to standard
1T
Barriers to Trade (TBT) Committee.
temperature, torr.
P = final ammonia pressure corrected to standard
2T
2. Referenced Documents
temperature, torr.
2
2.1 ASTM Standards:
4. Summary of Test Method
D3766 Terminology Relating to Catalysts and Catalysis
E105 Guide for Probability Sampling of Materials 4.1 A sample is degassed by heating under vacuum to
remove adsorbed vapors from the surface. The sample is then
exposed to an excess of gaseous ammonia and the excess
1
This test method is under the jurisdiction of ASTM Committee D32 on
ammonia is removed by freezing it into a trap cooled with
Catalysts and is the direct responsibility of Subcommittee D32.01 on Physical-
liquid nitrogen. The chemisorbed ammonia is calculated as the
Chemical Properties.
difference between the volume of ammonia before exposure
Current edition approved Feb. 1, 2024. Published February 2024. Originally
approved in 1988. Last previous edition approved in 2018 as D4824 – 13 (2018).
and the volume recovered in the liquid nitrogen trap.
DOI: 10.1520/D4824-24.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5. Significance and Use
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1 This test method can be used to determine the acidity of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. catalysts and catalyst carriers by ammonia chemisorption for
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D4824 − 24
materials specifications, manufacturing control, and research 6.1.13 Drying Tube, for drying ammonia gas (for example,
and development in the evaluation of catalysts. a 3A molecular sieve or BaO).
7. Sampling
6. Apparatus
7.1 A test sample shall be obtained from larger composites
6.1 A schematic diagram of one type of apparatus is shown
by riffling or splitting in accordance with subsection 5.12 of
in Fig. 1. It may be constructed of g
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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: D4824 − 13 (Reapproved 2018) D4824 − 24
Standard Test Method for
Determination of Catalyst Acidity by Ammonia
1
Chemisorption
This standard is issued under the fixed designation D4824; 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.
INTRODUCTION
This test method involves the measurement of total catalyst acidity by chemisorption of ammonia
in a static volumetric system. Acidity is a very important property in determining catalyst activity and
selectivity in many commercial reactions. Zeolite based catalysts used in the petroleum industry for
catalytic cracking are a prime example. This test method describes a simple procedure employing
inexpensive equipment that could readily be assembled in most laboratories.
1. Scope
1.1 This test method covers the determination of acidity of catalysts and catalyst carriers by ammonia chemisorption. A volumetric
measuring system is used to obtain the amount of chemisorbed ammonia.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered 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.
1.4 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
2.1 ASTM Standards:
D3766 Terminology Relating to Catalysts and Catalysis
E105 Guide for Probability Sampling of Materials
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
1
This test method is under the jurisdiction of ASTM Committee D32 on Catalysts and is the direct responsibility of Subcommittee D32.01 on Physical-Chemical
Properties.
Current edition approved Nov. 1, 2018Feb. 1, 2024. Published December 2018February 2024. Originally approved in 1988. Last previous edition approved in 20132018
as D4824 – 13. DOI: 10.1520/D4824-13R18.– 13 (2018). DOI: 10.1520/D4824-24.
2
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D4824 − 24
3. Terminology
3.1 Definitions—See Terminology D3766.
3.2 Symbols:
3
V = calibrated expansion volume, cm .
k
T = temperature of V at initial ammonia pressure, K.
1 k
T = temperature of V at final ammonia pressure, K.
2 k
P = initial ammonia pressure, torr.
1
P = final ammonia pressure, torr.
2
W = mass of sample, g.
s
W = tare of sample tube, g.
1
W = sample mass plus tare of tube, g.
2
P = initial ammonia pressure corrected to standard temperature, torr.
1T
P = final ammonia pressure corrected to standard temperature, torr.
2T
4. Summary of Test Method
4.1 A sample is degassed by heating in a under vacuum to remove adsorbed vapors from the surface. The sample is then exposed
to an excess of gaseous ammonia and the excess ammonia is removed by freezing it into a trap cooled with liquid nitrogen. The
chemisorbed ammonia is calculated as the difference between the volume of ammonia before exposure and the volume recovered
in the liquid nitrogen trap.
5. Significance and Use
5.1 This test method can be used to determine the acidity of catalysts and catalyst carriers by ammonia chemisorption for materials
specifications, manufacturing control, and research and development in the evaluation of catalysts.
6. Apparatus
6.1 A schematic diagram of one type of apparatus is shown in Fig. 1. It may be constructed of glass or metal an
...
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