Communications
with distilled water, drying at 1008C for 12 h, and by cal-
cination at 5008C for 3 h.
Table 2. Reductive amination of various ketones and an aldehyde by Pt-MoOx/TiO2
catalyst.[a]
According to the method in our previous studies,[23,24]
the Pt-MoOx/TiO2 catalyst (with Pt loading of 5 wt% and
Mo loading of 7 wt%) was prepared by sequential im-
pregnation method. First, the MoO3-loaded TiO2 as the
support material was prepared as follows; the mixture of
TiO2 (5 g), (NH4)6Mo7O24·4H2O (0.88 mmol), and citric acid
(0.88 mmol) in H2O (50 mL) was evaporated at 508C, fol-
lowed by drying at 1008C for 12 h, and by calcination in
air at 3508C for 2 h. The MoO3-loaded TiO2 was mixed
with an aqueous HNO3 solution of Pt(NH3)2(NO3)2, and
the mixture was evaporated at 508C, followed by drying
at 1008C for 12 h. To prepare the catalyst (Pt-MoOx/TiO2)
before each catalyst test, this precursor was reduced at
3008C under the hydrogen flow (0.5 h). Other supported
Pt catalysts (with Pt loading of 5 wt%) were prepared by
a similar impregnation method using various support
materials and the solution of Pt(NH3)2(NO3)2.
Entry
Reactants
Conv. [%]
Yield [%]
2
3
4
1
100
98
75 (71)[b]
7
11
2[c]
70
68
13
10
7
3
4
97
95
4
3
A typical method of catalytic tests is as follows. After the
pre-reduction at 3008C, the Pt-MoOx/TiO2 catalyst
(19.5 mg, containing 0.005 mmol of Pt) in the closed
glass tube with a septum inlet was cooled to room tem-
perature under H2, followed by injection of the mixtures
of substrates (1.0 mmol), dodecane (0.5 mmol) in o-
xylene (3.0 mL) to the reduced catalysts inside the glass
tube through the septum inlet. The septum was re-
moved, and a magnetic stir was put into the glass tube
under air. The glass tube was put into the stainless auto-
clave with a dead space of 33 mL. Subsequently, the au-
toclave was purged by flushing of NH3 and was filled
with 4 bar NH3 and 2 bar H2. The autoclave was heated
at 80–1508C under stirring (300 rpm). Conversion and
yields of products were determined by GC (Shimadzu
GC-14B) with Ultra ALLOY capillary column UA+-1 (Fron-
tier Laboratories Ltd.) using n-dodecane as an internal
standard. The products were identified by GC-MS (Shi-
madzu GCMS-QP2010) equipped with the same column
as GC. GC yields of primary amines were determined by
GC adopting the GC-sensitivity estimated using commer-
cial amines or the amines isolated after the catalytic re-
actions. For the reaction of 2-adamantanone (Table 2,
entry 1), a separate experiment was performed to deter-
64
<1
5
6
7
100
98
71
60
77
10
8
10
14
3
95
3
8[d]
96
92
74
9
<1
<1
6
9
70
[a] Conversion and yields were determined by GC based on 1. [b] Isolated yield.
[c] T=808C. [d] T=1508C.
depended on the Lewis acid strength of the support materials,
mine the isolated yield of 2-adamantlyamine as follows. After the
reaction, the catalyst was removed by filtration and then the reac-
tion mixture was concentrated under vacuum evaporator to
remove the volatile compounds. The residue thus obtained was
subjected to column chromatography (silica gel 60, Kanto Chemi-
cal) with CH2Cl2/n-hexane (4:1) mixture as the eluting solvent, fol-
suggesting that Lewis acid sites on the support material could
play an important role in this catalytic system.
1
lowed by analyses by H NMR (JEOL ECX-600), 13C NMR and GCMS.
Experimental Section
2-Adamantlyamine (0.71 mmol) was identified by the following
data: H NMR (600.17 MHz, CDCl3 with TMS): d=2.98 (s, 1H), 1.97
(d, J=13.1 Hz, 2H), 1.82–1.80 (m, 3H), 1.77–1.74 (m, 3H), 1.70–1.68
(m, 4H), 1.52 (d, J=13.08 Hz, 2H), 1.45 ppm (br s, 2H); 13C NMR
(150.92 MHz, CDCl3): d=55.43, 38.02, 37.62 (Cꢁ2), 35.10 (Cꢁ2),
30.71 (Cꢁ2), 27.71, 27.50 ppm; GC-MS m/e 151.14.
Commercially available organic compounds (from Tokyo Chemical
Industry and Wako Pure Chemical Industries) were used without
further purification. TiO2 (JRC-TIO-4), MgO (JRC-MGO-3), and CeO2
(JRC-CEO-3) were supplied by the Catalysis Society of Japan. SiO2
(Q-10, 300 m2 gÀ1) was supplied from Fuji Silysia Chemical Ltd.
HZSM-5 zeolite with a SiO2/Al2O3 ratio of 22.3 was supplied by
Tosoh Co. Active carbon (C) was purchased from Kanto Chemical.
q-Al2O3 was prepared by calcination of g-AlOOH (Catapal B Alumina
purchased from Sasol) at 10008C for 3 h. Nb2O5 was prepared by
calcination of Nb2O5·nH2O (supplied by CBMM) at 5008C for 3 h.
ZrO2 was prepared by hydrolysis of zirconium oxynitrate 2-hydrate
by an aqueous NH4OH solution, followed by filtration, washing
1
IR spectra were recorded at 408C by using a JASCO FT/IR-4200
with an MCT detector. The catalyst disc (30 mg, f=2 cm) was
mounted in the IR cell with CaF2 windows connected to a flow re-
action system. Spectra were measured accumulating 15 scans at
a resolution of 4 cmÀ1. A reference spectrum of the catalyst disc in
flowing He was subtracted from each spectrum. Prior to the experi-
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