ASTM D3942-03
(Test Method)Standard Test Method for Determination of the Unit Cell Dimension of a Faujasite-Type Zeolite
Standard Test Method for Determination of the Unit Cell Dimension of a Faujasite-Type Zeolite
SIGNIFICANCE AND USE
Zeolites Y and X, particularly for catalyst and adsorbent applications, are a major article of manufacture and commerce. Catalysts and adsorbents comprising these zeolites in various forms plus binder and other components have likewise become important. Y-based catalysts are used for fluid catalytic cracking (FCC) and hydrocracking of petroleum, while X-based adsorbents are used for desiccation, sulfur compound removal, and air separation.
The unit cell dimension of a freshly synthesized faujasite-type zeolite is a sensitive measure of composition which, among other uses, distinguishes between the two synthetic faujasite-type zeolites, X and Y. The presence of a matrix in a Y-containing catalyst precludes determination of the zeolite framework composition by direct elemental analysis.
Users of the method should be aware that the correlation between framework composition and unit cell dimension is specific to a given cation form of the zeolite. Steam or thermal treatments, for example, may alter both composition and cation form. The user must therefore determine the correlation that pertains to his zeolite containing samples.3 In addition, one may use the method solely to determine the unit cell dimension, in which case no correlation is needed.
Other crystalline components may be present in the sample whose diffraction pattern may cause interference with the selected faujasite-structure diffraction peaks. If there is reason to suspect the presence of such components, then a full diffractometer scan should be obtained and analyzed to select faujasite-structure peaks free of interference.
SCOPE
1.1 This test method covers the determination of the unit cell dimension of zeolites having the faujasite crystal structure, including synthetic Y and X zeolites, their modifications such as the various cation exchange forms, and the dealuminized, decationated, and ultra stable forms of Y. These zeolites have cubic symmetry with a unit cell parameter usually within the limits of 24.2 and 25.0 (2.42 and 2.50 nm).
1.2 The samples include zeolite preparation in the various forms, and catalysts and adsorbents containing these zeolites. The zeolite may be present in amounts as low as 5 %, such as in a cracking catalyst.
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.
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Designation:D3942–03
Standard Test Method for
Determination of the Unit Cell Dimension of a Faujasite-
1
Type Zeolite
This standard is issued under the fixed designation D3942; 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 ing (FCC) and hydrocracking of petroleum, while X-based
adsorbents are used for desiccation, sulfur compound removal,
1.1 This test method covers the determination of the unit
and air separation.
celldimensionofzeoliteshavingthefaujasitecrystalstructure,
4.2 The unit cell dimension of a freshly synthesized
including synthetic Y and X zeolites, their modifications such
faujasite-type zeolite is a sensitive measure of composition
as the various cation exchange forms, and the dealuminized,
which, among other uses, distinguishes between the two
decationated, and ultra stable forms of Y. These zeolites have
synthetic faujasite-type zeolites, X and Y. The presence of a
cubic symmetry with a unit cell parameter usually within the
matrixinaY-containingcatalystprecludesdeterminationofthe
limits of 24.2 and 25.0 Å (2.42 and 2.50 nm).
zeolite framework composition by direct elemental analysis.
1.2 The samples include zeolite preparation in the various
4.3 Usersofthemethodshouldbeawarethatthecorrelation
forms, and catalysts and adsorbents containing these zeolites.
between framework composition and unit cell dimension is
The zeolite may be present in amounts as low as 5%, such as
specific to a given cation form of the zeolite. Steam or thermal
in a cracking catalyst.
treatments,forexample,mayalterbothcompositionandcation
1.3 This standard does not purport to address all of the
form. The user must therefore determine the correlation that
safety concerns, if any, associated with its use. It is the
3
pertains to his zeolite containing samples. In addition, one
responsibility of the user of this standard to establish appro-
may use the method solely to determine the unit cell dimen-
priate safety and health practices and determine the applica-
sion, in which case no correlation is needed.
bility of regulatory limitations prior to use.
4.4 Other crystalline components may be present in the
2. Referenced Documents
sample whose diffraction pattern may cause interference with
the selected faujasite-structure diffraction peaks. If there is
2.1 ASTM Standards:
reason to suspect the presence of such components, then a full
E691 Practice for Conducting an Interlaboratory Study to
2
diffractometer scan should be obtained and analyzed to select
Determine the Precision of a Test Method
faujasite-structure peaks free of interference.
3. Summary of Test Method
5. Apparatus
3.1 A sample of the zeolite Y or X, or catalyst containing
5.1 X-Ray Diffractometer, able to scan at 0.25° 2u/min. 2u
zeolite is mixed with powdered silicon. The zeolite unit cell
values in the following discussions were based on data
dimension is calculated from the X-ray diffraction pattern of
obtained with a copper tube, although other tubes such as
the mixture, using the silicon reflections as a reference.
molybdenum can be used.
4. Significance and Use
NOTE 1—A step-scanning accessory, to scan at a rate of 0.25° or less
4.1 ZeolitesYandX,particularlyforcatalystandadsorbent
2u/min, will increase the accuracy of the determination and will facilitate
applications,areamajorarticleofmanufactureandcommerce. measurement in samples of low zeolite content.
Catalysts and adsorbents comprising these zeolites in various
5.2 Drying Oven, set at 110°C.
formsplusbinderandothercomponentshavelikewisebecome
important. Y-based catalysts are used for fluid catalytic crack-
3
Three correlations have been published for pure synthetic faujasite-type
1
This test method is under the jurisdiction of ASTM Committee D32 on zeolites in the sodium or calcium form: Breck, D. W. and Flanigen, E. M. in“
Catalysts and is the direct responsibility of Subcommittee D32.05 on Zeolites. MolecularSieves”,SocietyofChemicalIndustry,London,1968,p.47,WrightA.C.,
Current edition approved March 10, 2003. Published April 2003. Originally Rupert, J. P. and Granquist W. T. Amer. Mineral., Vol 53, 1968, p. 1293; and
approved in 1980. Last previous edition approved in 1997 as D3942–97. Dempsy,E.,Kuehl,G.H.,andOlson,D.H., Journal of the Physical Chemistry,Vol
2
Annual Book of ASTM Standards, Vol 14.02. 73, 1968, p. 387.
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D3942–03
flections must be used are 28.443° 2u (Cu Ka ) and 28.467° 2u (Cu Ka).
5.3 Hydrato
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