Y. Sugi et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 7 (2007) 1427
bulky isomers predominantly diffuse out from the mixtures in-
side the channels, is not operated in these alkylations, because
corrugated zeolites.25 These results also support the above dis-
cussion that the shape-selectivity of zeolites is governed by the
exclusion of bulky isomers at the transition states by steric re-
striction in the channels of the zeolites.
0
the selective formation of 4,4 -DABP was accompanied by
their high selectivities in the encapsulated products. The iso-
0
merization of 4,4 -DABP inside the channels may not be rapid
to establish or approach an equilibrium.
Conclusion
0
The isomerization of 4,4 -DABP occurred in some alkyla-
ꢁ
Alkylation, i.e., isopropylation, s-butylation, and t-butyla-
tion, of BP was examined over the 14-MR zeolites CFI,
tions at high temperatures, such as 300–350 C: isopropylation
over MOR and CFI, s-butylation over MOR, and t-butylation
0
DON, and SFH. CFI yielded 4,4 -DIPB shape-selectively in
the isopropylation. However, the predominant DIPB isomers
over MOR, CFI, and SFH. In these cases, the selectivities
0
0
for 4,4 -DABP in the encapsulated products remained high
even at high temperatures, except in the isopropylation over
were 2,x -DIPB with 2-isopropyl group over DON and SFH,
0
and the selectivities for 4,4 -DIPB were 10–15% in both bulk
0
0
CFI. The isomerization of 4,4 -DABP during the alkylation
and encapsulated products. The selectivities for 4,4 -DSBB
0
occurs at the external acid sites as discussed for the isopropyla-
tion of BP over MOR in previous papers.1 These results show
that the channels of these zeolites are too small for the isomer-
and 4,4 -DTBB were enhanced by using bulky alkylating
agent, 1-butene, and 2-methylpropene, respectively. Particular-
–7
0
ly, 4,4 -DTBB was obtained selectively in the t-butylation over
all zeolites.
0
ization of 4,4 -DABP. However, the isopropylation of BP over
CFI has a different feature among the 14-MR zeolites: the se-
These differences are due to the spatial difference inside
their channels: CFI with slightly corrugated one-dimensional
channels (16-MR cavity with a pore-entrance of 0.72 nm ꢂ
0.75 nm), DON with straight one-dimensional channels (pore-
entrance = 0.74 nm ꢂ 0.95 nm), and SFH with largely corru-
gated one-dimensional channels (22-MR cavity with a pore-
entrance of 0.65 nm ꢂ 0.88 nm). They are also due to bulki-
ness of alkylating agents: propene, 1-butene, and 2-methylpro-
0
lectivities for 4,4 -DIPB in both bulk and encapsulated prod-
ucts in the isopropylation over CFI gradually decreased with
an increase in the temperature, and they decreased to around
ꢁ
3
0% at 350 C. The channels of CFI are large enough for the
0
isomerization of 4,4 -DIPB at both external and internal acid
sites at high temperatures. However, there is another possibil-
ity that the decrease in the steric restriction by CFI channels
0
0
causes a decrease in the selectivity for 4,4 -DIPB at high tem-
pene. The selectivity for 4,4 -DABP was governed by the ex-
peratures. No significant isomerization in the s-butylation and
the t-butylation over DON. This is due to the weak acidity, and
not due to the zeolite structure. However, further research on
these aspects is necessary for full understanding.
We have found the shape-selective formation of 4,4 -DIPB
in the isopropylation of BP over several one-dimensional 12-
clusion of bulky isomers at transition states by the steric re-
striction inside their channels. The exclusion of bulky isomers
from large channels occurs effectively if the transition states
are large enough for the differentiation of the least bulky iso-
mers from the isomers by using bulky alkylating agent, such as
in the t-butylation over DON and SFH.
0
1
–7
MR zeolites with straight channels: H-Mordenite (MOR),
21
ZSM-12 (FTC: MTW),20 SSZ-24 (FTC: AFI), MAPO-5
A part of this work was financially supported by a Grant-in
Aid for Scientific Research (B) 1631005, the Japan Society for
the Promotion of Science (JSPS) and by Research Project
under the Japan-Korea Basic Scientific Cooperation Program,
JSPS and Korea Science and Engineering Foundation
(KOSEF; Grant No. F01-2004-000-10510-0). S. A. R. Mulla
thanks to JSPS for the postdoctoral fellowship.
22
(
FTC: AFI; M: Mg, Ca, Sr, Ba, and Zn), SAPO-5 (FTC:
2
3
24
0
AFI), and SSZ-31. The selectivity level for 4,4 -DIPB
60–90%) reflected the reaction space in the zeolite channels:
(
MOR > SSZ-24, MAPO-5 (M: Mg, Ca, Sr, Ba, and Zn), and
SAPO-5 ꢆ SSZ-31 > ZSM-12. The highly selective forma-
0
tion of 4,4 -DABP has also been observed in the s-butylation
21–23
and the t-butylation over these zeolites.
4
Particularly,
,4 -DSBB and 4,4 -DTBB were selectively obtained over
SSZ-24 and SSZ-31, which have the largest channels among
Supporting Information
0
0
Figures S1–S6: The influences of yields of alkylates in the
alkylation of BP. Figures S7–S9: Images of structure of CFI,
DON, and SFH zeolites. This material is available free of charge
1
2-MR zeolites.
The selectivities for 4,4 -DIPB over the one-dimensional
0
25
zeolites with corrugated channels, SSZ-55 (FTC; ATS),
SSZ-42 (FTC: IFR), and MAPO-36 (FTC: ATS; M: Mg
and Zn)
25
2
6,27
were around 20–40%. These zeolites have similar
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