Chem. Mater - Kennedy - 2 papers on new mesoporous AlPO; 31P, 27Al

Chem. Mater., ASAP Article 10.1021/cm052174r S0897-4756(05)02174-5
Web Release Date: February 18, 2006

Synthesis and Characterization of a New Microporous Material. 1.
Structure of Aluminophosphate EMM-3

Mobae Afeworki, Douglas L. Dorset, Gordon J. Kennedy, and Karl G.
Strohmaier*
ExxonMobil Research & Engineering Company, 1545 Rt. 22 East, Annandale,
New Jersey 08801

Abstract:

Molecular sieves are extensively used in the chemical and petrochemical
industry as catalysts, absorbents, and ion exchangers. New molecular
sieve structures have the potential to improve the performance of these
materials. We have discovered a new microporous material, EMM-3,
prepared in both aluminophosphate and silicoaluminophosphate
compositions by use of N,N,N,N',N',N'-hexamethyl-1,6-hexanediammonium as
a template at 160 C in 20 h. The structure of EMM-3 has been solved and
refined from powder data by use of synchrotron X-ray radiation. The unit
cell for the calcined AlPO form of EMM-3 has monoclinic space group
symmetry, I2/m11, with cell dimensions a = 10.3132(2), b = 12.6975(3),
and c = 21.8660(4) and = 89.656(1). The microporous structure contains
12-ring, sinusoidal, unidimensional channels with pore openings of 6.1 ×
6.5 Å. This new framework contains two new building chains, not observed
in other known framework structures. The 31P and 27Al NMR spectra of the
calcined/dehydrated form are in agreement with a fully connected
tetrahedral structure containing five unique phosphorus and five unique
aluminum atoms. The material is stable upon calcination and absorbs 9-10
wt % hydrocarbons.

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Chem. Mater., ASAP Article 10.1021/cm052175j S0897-4756(05)02175-7
Web Release Date: February 18, 2006

Synthesis and Characterization of a New Microporous Material. 2. AlPO
and SAPO Forms of EMM-3
Mobae Afeworki, Gordon J. Kennedy, Douglas L. Dorset, and Karl G.
Strohmaier*

ExxonMobil Research & Engineering Company, 1545 Rt. 22 East, Annandale,
New Jersey 08801

Abstract:

A new aluminophosphate (AlPO) material, EMM-3, was recently synthesized
at ExxonMobil. EMM-3, ExxonMobil material no. 3, was synthesized in both
the AlPO- and SAPO-forms. The structure of the AlPO-form of EMM-3 has
been solved using FOCUS Fourier recycling method with the help of a
series of characterization techniques. Multinuclear, multifield
solid-state NMR, SEM, and powder XRD measurements were performed in
order to help understand the molecular arrangement and structure of the
material. Carbon-13 CPMAS NMR of the as-synthesized material shows that
the structure-directing agent remains intact with no strong chemical
shift anisotropy indicating considerable mobility of the
structure-directing agent in the internal voids of EMM-3. The
multitechnique characterization of EMM-3 shows that only one type of
crystal morphology is present, indicating the high purity of the sample.
The XRD pattern of calcined-dry EMM-3 is consistent with orthorhombic
symmetry. Distinct changes in local symmetry of the P and Al atoms occur
upon calcination and subsequent hydration, and these changes are
observed by solid-state NMR. Whereas the 31P MAS NMR of calcined-dry
EMM-3 shows three peaks in a ratio of 1:2:3, upon rehydration, the 31P
MAS NMR of EMM-3 shows that there are at least five distinct
environments for the P atoms in a ratio of 1:2:1:1:1. The
calcined-rehydrated sample shows a strong octahedral 27Al signal, due to
framework hydration. SAPO-forms of EMM-3 were successfully synthesized
and show acid activities. The Brnsted acidity was measured
quantitatively by 1H MAS NMR.