Tetraalkylphosphonium Cations as SDAs
A R T I C L E S
Table 1. Crystallographic Refinement Data for ITQ-27
Scheme 1. Synthesis of Diphenyldimethylphosphonium
molecular formula
Al5Si147O304
formula weight
9127.3
a (Å)
b (Å)
27.7508(5)
25.2969(7)
13.7923(4)
9682.3(3)
1
c (Å)
V (Å)3
Z
an anionic exchange resin in batch overnight. The synthesis was carried
out under hydrothermal conditions in Teflon-lined stainless steel
autoclaves and continuous stirring from a gel of composition:
space group
calculated density
T (°C)
Fmmm (no. 69)
1.565 g/cm
25
0.8702
9400
11.8%
3.77
11.5%
5.9%
3
λ Å
Nobs
2
SiO : 0.014 Al O : 0.50 Me Ph POH: 0.50 HF: 4.2 H O
R
ø
2
2
3
2
2
2
F
2
a
Rwp
In this synthesis, 9.73 g of tetraethyl orthosilicate (TEOS) and 0.28 g
of aluminum isopropoxide were hydrolyzed in 86.01 g of diphenyldi-
expected Rwpb
methylphosphonium hydroxide (Me
2
Ph
2
POH) solution with a concen-
a Rwp ) {∑w(I - I )2/∑wI 2}1/2 where I ) observed intensity of each
o c o o
b
tration of 0.27 mol/1000 g of solution. The mixture was then stirred at
room temperature until the Si and Al precursors were completely
hydrolyzed and the water and alcohol evaporated to the final gel
concentration. Finally, 0.97 g of a HF solution (48 wt %) was added,
and the mixture was homogenized by stirring and was autoclaved at
point and Ic ) calculated intensity of each point. Expected Rwp ) Rwp/
2 1/2
{
ø } .
microscope film, developed in Kodak HRP developer. Reciprocal
spacings in diffraction patterns were calibrated against a gold powder
standard.
1
50 °C under tumbling for 59 days. The solid recovered by filtration,
All of the solid-state NMR measurements were made at room
washed with distilled water, and dried at 373 K is pure ITQ-27.
Elemental analysis gave: 38.2 Si, 1.24 Al, 2.49 P, 13.52 C, 1.25 H,
and 0.50 F (wt %), indicating that the SDA molecule is intact within
the zeolite channels. The pure crystallized zeolite was calcined in air
for 3 hours at 580 °C to remove the organic template and fluorine.
Elemental analysis of the calcined sample after calcination (2.0 wt %
P) showed that the phosphorus was not completely removed.
temperature. The 27Al, Si MAS, and Si CPMAS NMR spectra were
29
29
recorded on a Varian InfinityPlus-500 spectrometer operating at 11.7
1
T ( H 499.2 MHz) corresponding to 130 and 99 MHz. Larmor
frequencies for 27Al and Si, respectively. Si MAS (Bloch decay)
29
29
and CPMAS NMR were recorded using a 7.5 mm Varian probe at
29
spinning speeds of 4 and 3.5 kHz, respectively. Si MAS (Bloch decay)
1
data were recorded with H decoupling during data acquisition, 4 µs
Conventional X-ray diffraction measurements on a calcined/hydrated
sample were measured on a laboratory instrument with Cu KR radiation
with Bragg-Brentano geometry. A calcined/dehydrated sample was
prepared for Debye-Scherrer X-ray diffraction measurement by
outgassing the calcined/hydrated ITQ-27 sample in a sealed quartz
capillary at 300 °C under vacuum (<0.1 Torr). The synchrotron powder
diffraction measurement of this sample was made at the ExxonMobil
beam line X10B (λ ) 0.87020 Å) at the Brookhaven National
Laboratory. The room-temperature pattern was measured from 3 to 50°
2
9
π/2 pulses, a 60 s pulse delay, and 720 scans were collected. Si CP/
1
MAS data were recorded with H decoupling during data acquisition,
4
µs π/2 pulses, 3.5 ms contact time, a 3 s pulse delay, and 4000 scans
27
were collected. Al MAS (Bloch decay) NMR spectra were recorded
1
using a 4 mm Varian probe at spinning speeds of 10 kHz with H dipolar
decoupling during data acquisition, 1.2 µs π/2 pulses, a 0.3 s pulse
delay, and 1600 scans were collected. The 13C and P MAS NMR
spectra were recorded on a Varian InfinityPlus-400 spectrometer
31
1
operating at 9.4 T ( H 399.4 MHz) corresponding to Larmor frequencies
2
θ with a 0.005° step size. In addition to single-crystal electron
of 100.4 and 161.7 MHz, respectively. 13C MAS (Bloch decay) NMR
spectra were recorded using a 4 mm Varian probe at spinning speeds
diffraction evaluations (see below) patterns were also indexed with the
1
0
Jade software. The crystal structure was solved using the direct
1
1
1
of 10 kHz with H dipolar decoupling during data acquisition, 1.8 µs
methods software package FOCUS. Rietveld refinements of the
structural models were made with software program GSAS,12 with the
crystallographic data given in Table 1. Silicate models used for Rietveld
refinement were first geometrically refined by DLS to optimize
bonding parameters.
31
π/2 pulses, a 60 s pulse delay, and 2400 scans were collected. P MAS
Bloch decay) NMR spectra were recorded using a 7.5 mm Varian probe
(
1
1
3
at spinning speeds of 5 kHz with H dipolar decoupling during data
acquisition, 4 µs π/2 pulses, a 300 s pulse delay, and 8 scans were
collected. The 27Al and P chemical shifts are referenced with respect
31
Absorption measurements were performed on samples calcined in
air at 580 °C for 3 hours.
3
+
to external solutions of Al(H
2
O)
6
(δAl ) 0.0 ppm) and 85% H
3
PO
4
29
(
δ
P
) 0.0 ppm), respectively. The 13C and Si chemical shifts are
Transmission electron diffraction measurements were initially carried
out at 200 kV with a JEOL JEM-2010 electron microscope, an
instrument that did not permit tilting of the specimen. Later, (45°
goniometric tilts of individual microcrystals around reciprocal lattice
rows were permitted with the use of a 300 kV FEI/Philips CM-30
instrument. The zeolite sample was first crushed to a fine powder in a
mortar and pestle and then suspended in acetone in an ultrasonic bath.
Drops of the fine particle suspension were then dried on carbon-film-
covered 300-mesh copper electron microscope grids. Selected area
electron diffraction patterns were recorded on Kodak SO-163 electron
referenced with respect to external solutions of tetramethylsilane with
19
δ ) 0.0 ppm and δSi ) 0.0 ppm. The F MAS NMR spectra were
C
19
recorded at an F frequency of 469.667 MHz on a Varian InfinityPlus
(11.7 T) NMR spectrometer using a 3.2 mm MAS probe, 18 kHz
spinning speed, 4 µs pulses, 240 scans, and a 20 s pulse delay.
Results
Pure samples of ITQ-27 can be recovered from aluminosili-
cate synthesis after relatively long crystallization times (59 days).
Subsequent attempts to prepare ITQ-27 with seeds from previous
synthesis only shortened the crystallization time by one week.
The porosity of the calcined ITQ-27 sample was measured by
adsorbing nitrogen and argon, and the results obtained are given
(
(
(
(
10) Jade 6: XRD Analysis Software, ver. 6.5.10; Materials Data, Inc.:
Livermore, CA, 2003.
11) Grosse-Kuntstleve, R. W.; McCusker, L. B.; Baerlocher, Ch. J. Appl.
Crystallogr. 1999, 32, 536.
3
12) Larsson A. C.; von Dreele, R. B. GSAS: General Structure Analysis System;
Los Alamos Laboratory: Los Alamos, NM, 1994.
in Table 2. The micropore volume of 0.21 cm /g and pore
diameter of 6.7 Å indicate that the material is most likely a
two-dimensional, possibly three-dimensional, large-pore zeolite.
13) Baerlocher, Ch.; Hepp, A.; Meier, W. M Distance Least Squares Refinement
Program, DLS-76; ETH: Z u¨ rich, 1977.
J. AM. CHEM. SOC.
9
VOL. 128, NO. 27, 2006 8863