II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-51
Pd SUPPORTED ON SURFACE-TREATED CNF AND THEIR CATALYTIC
ACTIVITY IN HECK REACTIONS BETWEEN ARYL HALIDES AND OLEFINS
Zhu J., Li K., Zhou J., Sui Z., Dai Y., Yuan W.
State Key Laboratory of Chemical Engineering, East China University of Science &
Technology, Shanghai, 200237, P. R. China
e-mail: zhujun0208@163.com
The olefination of aryl halides (Heck reaction), one of the most important CC coupling
reactions in organic synthesis, is mostly catalyzed by palladium complexes in homogeneous
solution. Regarding industrial applications, however, these catalysts are expensive for their
difficulty to separate Pd from the reaction mixture and their hardness to reuse. Nowadays, the
problem concerning separation, recovery of the Pd complexes and thermal stability (high
reaction temperatures) have been trying to be overcome by using the heterogeneous palladium
system.
As a new kind of carbon materials, carbon monofilament (tubes and fibers), CNT and
CNF, has been testified to be a new catalysis material with unique characteristics. In this
paper, heterogeneous Pd catalysts were prepared by supporting the Pd precursor on surface
treated CNF, and then used in Heck reactions. We attempt to develop a new heterogeneous
catalyst for Heck reaction.
The CNF sample was produced by decomposition of CO over a γ-Al 2 O 3 supported 20
wt% Ni-Fe alloy. Cuffs, after different kinds of surface treatment, supported palladium
catalysts (1%Pd) were prepared by a standard incipient impregnation method using H 2 PdCl 4
as palladium precursors. For the sake of comparison, catalysts of Palladium supported on
active carbon and graphite were also produced through the same procedure. Heck reaction
was conducted in a three-necked flask equipped with a septum and a reflux condenser. The
qualitative and quantitative analysis of the reactant was performed by GC.
TCD Signal
0.84
0.83
0.82
0.81
0.80
0.79
0.78
40 80 120 160 200 240 280 320
Temparature/ o C
Fig.1 TPR of Pd/CNF
Cat 4
Cat 1
Cat 2
Cat 3
No.
Treatment Peak
Pd Pd Diameter Yield
of CNF temperature dispersion [a] (nm) [a] (%) [b]
Cat1 ―― 140 o C 22.3% 5.8 72
Cat2 HT [c] 118 o C 4.1% 26.4 33
Cat3 HNO3 130 o C 19.2% 6.7 68
Cat4 Acetone 160 o C 24.3% 5.3 78
Cat5 (AC) ―― 20.4% 6.4 35
Cat6
(Graphite)
―― 17.5% 7.0 25
Table 1. [a] Measured by CO-Chemisorption; [b] Reaction conditions:
bromobenzene, styrene, NEt 3 , 0.2mol% Pd, DMAc; T=140 o C and t=24h; [c]
Heat treatment in 1700 o C for 3h.
222