J. Penzien et al. / Journal of Catalysis 221 (2004) 302–312
303
catalytic activity of the material in hydroamination reactions
with the local environment of the metal cations.
A sample of phenyl-(1-phenylethylidene)amine was syn-
thesized as reference by the acid-catalyzed (CF3SO3H,
3
0
0
.03 g, 0.2 mmol) condensation of aniline (27.3 cm ,
3
.3 mol) with acetophenone (29.2 cm , 0.25 mol) in toluene
3
◦
2
. Experimental
(50 cm ) at reflux temperature (111 C, 12 h). The reaction
mixture was dried over MgSO4 and distilled (product frac-
◦
2
.1. Materials and methods
tion: 110 C, 30 mm). The product was recrystallized from
hexane and analyzed using IR and NMR spectroscopy. The
spectra for phenyl-(1-phenylethylidene)aminewere identical
with those for the product of the reaction between pheny-
lacetylene and aniline.
All reactions involving air- and/or water-sensitive com-
pounds were performed using standard Schlenk techniques.
Dry solvents were obtained from Aldrich; 6-aminohex-
1
-yne, 2-methyl-1,2-dehydropiperidine, and tetrahydro-2-
methyl-1,3-oxazine were prepared as described in [11,12].
Catalysts and other chemicals not described in the exper-
imental section were purchased from Aldrich, Fluka, or
Strem and used as received.
2.4. Preparation of ion exchanged zeolites
Zeolite BEA in the acidic form was used as the parent ma-
terial (diameter of the crystals 0.1–0.3 µm, Si/Al 11.6, BET
2
surface area 537 m /g). Transition-metal-based zeolite cat-
+
2+
2+
2+
+
2+
2+
2
.2. Physical and analytical methods
alysts with Rh , Ni , Pd , Pt , Cu , Cu , and Zn
were prepared by ion exchange, for details, see Tables 1
and 2; for the oxidation state of the metal see Ref. [11]);
1H, 13C{ H}, and P{ H} NMR spectra were recorded
1
31
1
3
+
on a Bruker AM 400 instrument and referenced in ppm rel-
ative to tetramethylsilane using the solvent shift as internal
standard [13]. IR spectra were obtained on a Perkin-Elmer
FT-IR 2000 spectrometer as KBr pellets. Mass spectro-
scopic analyses were performed on a Finnigan MAT 311A
mass spectrometer by chemical ionization (CI). GC analyses
were performed on a Hewlett-Packard HP 5890 gas chro-
matograph equipped with a crosslinked 5% diphenyl–95%
dimethylpolysiloxane column (30 m, Restek GmbH, Rtx-5
Amine) and a flame ionization detector. GC-MS analyses
were performed on a Hewlett-Packard HP 5890 gas chro-
matograph equipped with an identical column and a mass-
selective detector HP 5971A.
La was introduced by solid-state ion exchange. Except for
+
+
Cu and Rh the ion exchange was performed by suspend-
ing the parent zeolite in an aqueous solution of the corre-
◦
sponding metal salt (80 C). The zeolite was separated by
centrifugation (5000 rpm, 20 min) and, to obtain a particular
ion-exchange degree, the procedure repeated. The material
was then calcined in a flow of air (100 ml/min). Prior to use,
the Ni2 -exchanged zeolite was reduced in hydrogen to ob-
+
0
tain a Ni -containing catalyst (see [11]). Further, a series of
zinc-exchanged BEA zeolites was prepared varying in the
zinc loading [14]. The full characterization of this series of
Zn/H-BEA zeolites is described elsewhere [15].
Copper(I) and rhodium(I) salts are susceptible to oxida-
tion and/or disproportionation. Therefore, the ion exchange
was carried out in anhydrous solvent (CH3CN) under an
inert conditions. The parent H-BEA zeolite was activated
2
.3. Synthesis and characterization of
phenyl-(1-phenylethylidene)amine
◦
at 150 C in vacuum (10 mbar). The zeolite was then sus-
3
Aniline (9.1 cm , 0.1 mol) and the catalyst Zn(CF3SO3)2
3.6 g, 0.01 mmol) were dissolved in toluene (180 cm )
pended in a solution of the complexes [Cu(CH3CN)4]PF6 or
3
◦
(
[Rh(NOR)2]ClO4 (NOR, norbornadiene) in CH3CN (82 C;
and the mixture was heated to reflux temperature. The re-
action was started by addition of phenylacetylene (4.4 cm ,
for details, see Table 1). The solvent was removed under
vacuum and the sample subsequently handled in an inert
atmosphere. In case of lanthanum exchange, the parent ma-
terial was ground with LaCl3 × 7H2O in an agate ball mill
for 30 min. The mixture was heated in a stream of air (100
3
0
.04 mol) and the mixture refluxed overnight. Quantitative
conversion of phenylacetylene was indicated by GC analy-
sis. The product was separated by column chromatography
using silica gel 60 as stationary phase and hexane/ethyl ac-
etate 50/30 as eluent. The volatiles were removed and the
single product was characterized by NMR, MS (CI), GC-
MS, and IR analyses which confirmed the product to be
phenyl-(1-phenyl-ethylidene)-amine.
◦
◦
◦
◦
ml/min, RT–120 C, 2 C/min; 120 C 2 h; 120–500 C,
◦
◦
2 C/min), washed with distilled water, and dried at 100 C.
2.5. Catalytic experiments
1
Yield: 1.3 g, 16.7%. H NMR (CDCl3): δ 6.7–8 (m, 10H,
The metal-exchanged zeolites (corresponding to 5.3 ×
Ph), 2.2 (s, 3H, CH3) ppm. 13C{ H} NMR (CDCl3): δ 164.5
1
10 mmol M , if not stated otherwise) were activated
−3
n+
◦
(
C=N), 151.7 (N–C), 139.5 (Ph), 130.5 (Ph), 129.0 (Ph),
(12 h at 10 mbar, 200 C). The zeolites Cu(I)/H-BEA
1
1
1
28.4 (Ph), 127.2 (Ph), 123.3 (Ph), 119.4 (Ph), 115.1 (Ph),
8.0 (Me) ppm. IR: 3054 (m), 1630 (vs), 1591 (vs), 1446 (s),
and Rh(I)/H-BEA and the homogeneous catalysts were
used in an inert atmosphere without activation. Dry toluene
−1
3
214 (s), 761 (s), 693 (vs), 572 (w), 528 (w) cm . GC-MS:
(15 cm ) was added, the mixture heated to reflux tempera-
+
+
◦
m/z 180 (M –CH3). MS (CI) m/z 195 (M ).
ture (111 C), and the catalytic reaction started by addition
Penzien, Jochen
