ASTM D3908-03(2008)

Standard Test Method for Hydrogen Chemisorption on Supported Platinum Catalysts by Volumetric Vacuum Method

SIGNIFICANCE AND USE
This test method sets forth a procedure by which duplicate catalyst samples can be compared either on an interlaboratory or intralaboratory basis. It is anticipated that catalyst producers and users will find this test method of value.
Discrimination of the samples for which this procedure is recommended must be exercised when considering carrier (support) materials that sorb appreciable quantities of hydrogen or could cause an alteration of the state of the catalyst during pretreatment, or both, (that is, sintering or metal occlusion). These materials must be identified by the user and experimented with to determine the most significant conditions of measurement.
This test method provides a measure of the total hydrogen uptake (volume of hydrogen at STP, cm3/g of catalyst) without specifying the nature of the hydrogen-platinum interaction. Persons interested in using hydrogen uptake data to calculate percent platinum dispersion in a specific catalyst should be aware of carrier (support) interactions, spillover effects, and other phenomena related to the hydrogen uptake capabilities of the catalyst in question.
SCOPE
1.1 This test method covers the determination of the chemisorption of hydrogen at 298 K (25°C) on supported platinum catalysts that have been reduced in flowing hydrogen at 723 K (450°C). It incorporates a static volumetric vacuum technique at constant volume.
1.2 The test method is intended for use on unused supported platinum on alumina catalysts of loadings greater than 0.3 weight %. Data on other supports and lower platinum loadings were not tested.
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Mar-2008
• Technical Committee: D32 - Catalysts
• Drafting Committee: D32.01 - Physical-Chemical Properties

Relations

• Replaces: ASTM D3908-03 - Standard Test Method for Hydrogen Chemisorption on Supported Platinum on Alumina Catalysts and Catalyst Carriers By Volumetric Vacuum Method
• Effective Date: 01-Apr-2008

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D3908 − 03(Reapproved 2008)
Standard Test Method for
Hydrogen Chemisorption on Supported Platinum Catalysts
1
by Volumetric Vacuum Method
This standard is issued under the fixed designation D3908; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
P = pressure of gas in calibrated bulb, torr
1.1 This test method covers the determination of the
c
P = pressure of gas in calibrated bulb and
mc
chemisorption of hydrogen at 298 K (25°C) on supported
manifold, torr
platinum catalysts that have been reduced in flowing hydrogen
P = pressure in manifold, torr
m
at 723 K (450°C). It incorporates a static volumetric vacuum
P = pressure in manifold and dead space, torr
md
technique at constant volume.
P = pressure in manifold prior to expansion into
m
x
1.2 Thetestmethodisintendedforuseonunusedsupported
sample tube for X equilibration point, torr
platinum on alumina catalysts of loadings greater than 0.3
P = equilibrium pressure after expansion for gen-
e
x
weight %. Data on other supports and lower platinum loadings
erating X equilibrium point, torr
3
were not tested.
V = volume of calibrated bulb, cm
c
V = volume of manifold between stopcocks 12
m
1.3 This standard does not purport to address all of the
3
and 2 with only 4 and 1 open, cm
safety concerns, if any, associated with its use. It is the
V = volume of dead space in sample cell contain-
d
responsibility of the user of this standard to establish appro-
3
ing catalyst (volume between 2 and 3), cm
priate safety and health practices and determine the applica-
3
V (STP) = volume of gas adsorbed at STP, cm
ads x
bility of regulatory limitations prior to use.
V (STP) = cumulative volume of gas adsorbed through
ads cx
3
X,cm
2. Referenced Documents
V = monolayer volume of gas adsorbed at STP,
2 S
2.1 ASTM Standards:
3
cm
D3766Terminology Relating to Catalysts and Catalysis
T = temperature representative of the manifold
m
Ax
E177Practice for Use of the Terms Precision and Bias in
prior to expansion into the sample cell, K
ASTM Test Methods
T = temperature representative of the entire sys-
m
Bx
E456Terminology Relating to Quality and Statistics
tem after equilibrium pressure (P ) has been
e
x
E691Practice for Conducting an Interlaboratory Study to
established, K
Determine the Precision of a Test Method
T = temperature of manifold prior to expansion
m
intosamplecellfordeadspacedetermination,
3. Terminology
K
3.1 Definitions—See Terminology D3766.
T = temperatureofentiresystemafterequilibrium
m
D
pressure has been established for dead space
3.2 Quality and Statistics—See Terminology E456.
determination, K
3.3 Precision and Bias—See Practice E177.
T = average manifold temperature for a given
dose, K
3.4 Symbols—The following symbols are used:
=(T + T )/2
m m
Ax Bx
W = mass of catalyst, g
cat
1
This test method is under the jurisdiction of ASTM Committee D32 on
X = weight percent of platinum
Catalysts and is the direct responsibility of Subcommittee D32.01 on Physical-
%D = percent platinum atoms on the surface
Chemical Properties.
Current edition approved April 1, 2008. Published May 2008. Originally
4. Significance and Use
approved in 1980. Last previous edition approved in 2003 as D3908–03. DOI:
10.1520/D3908-03R08.
4.1 This test method sets forth a procedure by which
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
duplicate catalyst samples can be compared either on an
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
interlaboratory or intralaboratory basis. It is anticipated that
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. catalystproducersanduserswillfindthistestmethodofvalue.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D3908 − 03 (2008)
FIG. 1 Schematic: Static Vacuum System
4.2 Discrimination of the samples for which this procedure
is recommended must be exercised when considering carrier
(support)materialsthatsorbappreciablequantitiesofhydrogen
or could cause an alteration of the state of the catalyst during
pretreatment, or both, (that is, sintering or metal occlusion).
These materials must be identified by the user and experi-
mented with to determine the most significant conditions of
measurement.
4.3 This test method provides a measure of the total
3
hydrogen uptake (volume of hydrogen at STP, cm /g of
catalyst) without specifying the nature of the hydrogen-
platinum interaction. Persons interested in using h
...

This document is not anASTM standard and is intended only to provide the user of anASTM 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:D3908–99 Designation:D3908–03 (Reapproved 2008)
Standard Test Method for
Hydrogen Chemisorption on Supported Platinum on
Alumina Catalysts and Catalyst Carriers by Volumetric
Vacuum MethodHydrogen Chemisorption on Supported
1
Platinum Catalysts by Volumetric Vacuum Method
This standard is issued under the fixed designation D3908; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of the chemisorption of hydrogen at 298 K (25°C) on supported platinum
catalysts that have been reduced in flowing hydrogen at 723 K (450°C). It incorporates a static volumetric vacuum technique at
constant volume.
1.2 The test method is intended for use on unused supported platinum on alumina catalysts of loadings greater than 0.3 weight
%. Data on other supports and lower platinum loadings were not tested.
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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
D3766 Terminology Relating to Catalysts and Catalysis
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Symbols
3.1The following symbols are used: Terminology
3.1 Definitions—See Terminology D3766.
3.2 Quality and Statistics—See Terminology E456.
3.3 Precision and Bias—See Practice E177.
3.4 Symbols—The following symbols are used:
P = pressure of gas in calibrated bulb, torr
c
P = pressure of gas in calibrated bulb and manifold, torr
mc
P = pressure in manifold, torr
m
P = pressure in manifold and dead space, torr
md
P = pressure in manifold prior to expansion into sample tube for X equilibration point, torr
m
x
P = equilibrium pressure after expansion for generating X equilibrium point, torr
e
x
3
V = volume of calibrated bulb, cm
c
3
V = volume of manifold between stopcocks 12 and 2 with only 4 and 1 open, cm
m
3
V = volume of dead space in sample cell containing catalyst (volume between 2 and 3), cm
d
3
V (STP) = volume of gas adsorbed at STP, cm
ads x
3
V ( STP) = cumulative volume of gas adsorbed through X,cm
ads cx
1
This test method is under the jurisdiction of ASTM Committee D-32D32 on Catalysts and is the direct responsibility of Subcommittee D32.01 on Physical-Chemical
Properties.
Current edition approvedApril 10, 1999.1, 2008. Published June 1999.May 2008. Originally published as D3908–80.approved in 1980. Last previous edition D3908–88
e1
(1993) .approved in 2003 as D3908–03.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,[e-mail] Annual Book of ASTM Standards
, Vol 14.02.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 ----------------------
D3908–03 (2008)
3
V = monolayer volume of gas adsorbed at STP, cm
S
T = temperature representative of the manifold prior to expansion into the sample cell, K
m
Ax
T = temperature representative of the entire system after equilibrium pressure (P ) has been established, K
m e
Bx x
T = temperature of manifold prior to expansion into sample cell for dead space determination, K
m
T = temperature of entire system after equilibrium pressure has been established for dead space determination, K
m
D
T = average manifold temperature for a given dose, K
=(T + T )/2
m m
Ax Bx
W = weight of catalyst, gmass of catalyst, g
cat
X = weight percent of platinum
%D = percent platinum atoms on the surface
4. Significance and Use
4.1 This test method sets forth a procedure by which duplicate catalyst samples can be compared either on an interlaboratory
or intralaboratory basis. It is anticipated that catalyst producers and users will find this test method of value.
4.2 Discrimination of the samples for which this procedure is recommended must be exercised when considering carrier
(support) materials that ad(ab)sorbsorb a
...