The alkylation of biphenyl over one-dimensional twelve-membered ring zeolites. the influence of zeolite structure and alkylating agent on the selectivity for 4,4'-dialkylbiphenyl

Article abstract of DOI:10.1246/bcsj.80.2232

Alkylation, i.e., isopropylation, s-butylation, and t-butylation, of biphenyl (BP) was examined over one-dimensional twelve-membered (12-MR) zeolites: Mordenite (MOR) and SSZ-24 (AFI) with straight channels, and SSZ-55 (ATS) and SSZ-42 (IFR) with corrugated channels. Types of zeolites and alkylating agents highly influenced the selectivities for dialkylbiphenyl (DABP) isomers. Shape-selective formation of 4,4'-diisopropylbiphenyl (4,4'-DIPB) was observed over MOR and AFI; however, ATS and IFR gave 4,4'-DIPB only in low selectivities at 250°C: 87% over MOR, 60% over AFI, 20% over ATS, and 30% over IFR. The selectivities for 4,4'-di-s-butylbiphenyl (4,4'-DSBB) in the,s-butyl-ation were higher than those for 4,4'-DIPB: 95% over MOR, 85% over AFI, 75% over ATS, and 50% over IFR. The t-butylation afforded selectively 4,4'-di-t-butylbiphenyl (4,4'-DTBB) over the zeolites: 96-97% over MOR and AFI, 90% over ATS, and 80% over IFR. These results in the alkylation indicate the exclusion of 4,4'-DABP from other bulky DABP isomers by steric restriction in zeolite channels is an important key for the high shape-selectivity. Even zeolites with large channels, such as ATS and IFR, can have shape-selective nature if the bulky moieties, such as,s-butyl and t- butyl groups, are large enough to differentiate the transition state of the least bulky 4,4'-DABP from those of the other isomers inside their channels. The selectivity for 4,4'-DABP decreased at high temperatures in some alkylations: isopropylation over MOR, and s-butylation and t-butylation over MOR, AFI, and ATS. The decreases are due to the iso-merization of 4,4'-DABP at external acid sites, because the channels are not large enough for the isomerization of 4,4'-DABP to bulkier 3,4'-DABP. However, the isopropylation over AFI was accompanied by the isomerization of 4,4'-DIPB at external and internal acid sites, because the channels are large enough for the isomerization of 4,4'-DIPB.

Full text of DOI:10.1246/bcsj.80.2232

2232 Bull. Chem. Soc. Jpn. Vol. 80, No. 11, 2232–2242 (2007)
Ó 2007 The Chemical Society of Japan
The Alkylation of Biphenyl over One-Dimensional Twelve-Membered
Ring Zeolites. The Influence of Zeolite Structure and Alkylating
Agent on the Selectivity for 4,40-Dialkylbiphenyl
ꢀ1
Yoshihiro Sugi, Hiroyoshi Maekawa,1 Akira Ito,1 Chikako Ozawa,1
Tomoko Shibata,1 Akihiro Niimi,1 Chihara Asaoka,1 Kenichi Komura,1
y
Yoshihiro Kubota,1; Jae-Youl Lee,2 Jong-Ho Kim,2 and Gon Seo2
1Department of Materials Science and Technology, Faculty of Engineering, Gifu University, Gifu 501-1193
2School of Applied Chemical Engineering and The Research Institute for Catalysis, Chonnam National University,
Gwangju 500-757, Korea
Received April 2, 2007; E-mail: ysugi@gifu-u.ac.jp
Alkylation, i.e., isopropylation, s-butylation, and t-butylation, of biphenyl (BP) was examined over one-dimension-
al twelve-membered (12-MR) zeolites: Mordenite (MOR) and SSZ-24 (AFI) with straight channels, and SSZ-55 (ATS)
and SSZ-42 (IFR) with corrugated channels. Types of zeolites and alkylating agents highly influenced the selectivities
for dialkylbiphenyl (DABP) isomers. Shape-selective formation of 4,40-diisopropylbiphenyl (4,40-DIPB) was observed
over MOR and AFI; however, ATS and IFR gave 4,40-DIPB only in low selectivities at 250 ꢁC: 87% over MOR, 60%
over AFI, 20% over ATS, and 30% over IFR. The selectivities for 4,40-di-s-butylbiphenyl (4,40-DSBB) in the s-butyl-
ation were higher than those for 4,40-DIPB: 95% over MOR, 85% over AFI, 75% over ATS, and 50% over IFR. The t-
butylation afforded selectively 4,40-di-t-butylbiphenyl (4,40-DTBB) over the zeolites: 96–97% over MOR and AFI, 90%
over ATS, and 80% over IFR. These results in the alkylation indicate the exclusion of 4,40-DABP from other bulky
DABP isomers by steric restriction in zeolite channels is an important key for the high shape-selectivity. Even zeolites
with large channels, such as ATS and IFR, can have shape-selective nature if the bulky moieties, such as s-butyl and t-
butyl groups, are large enough to differentiate the transition state of the least bulky 4,40-DABP from those of the other
isomers inside their channels. The selectivity for 4,40-DABP decreased at high temperatures in some alkylations: iso-
propylation over MOR, and s-butylation and t-butylation over MOR, AFI, and ATS. The decreases are due to the iso-
merization of 4,40-DABP at external acid sites, because the channels are not large enough for the isomerization of 4,40-
DABP to bulkier 3,40-DABP. However, the isopropylation over AFI was accompanied by the isomerization of 4,40-DIPB
at external and internal acid sites, because the channels are large enough for the isomerization of 4,40-DIPB.
Shape-selective catalyses by zeolites occur by differentiat-
ing reactants, products, and/or reaction intermediates accord-
ing to their shapes and sizes in the sterically restricted environ-
ments of the zeolites.1–6 Only molecules that have dimensions
less than a critical size can enter zeolite pore and react at the
internal catalytic sites, and the bulky molecules, which cannot
accommodate in the channels, are excluded from the channels,
resulting in the preferential formation of the least bulky iso-
mers. Furthermore, only molecules that can diffuse through
the channels will appear in the products.
Isopropylation of biphenyl (BP) is a typical acid-catalyzed
reaction for demonstrating shape-selective nature of molecular
sieves.4–12 Selective formation of the least bulky 4,40-diiso-
propylbiphenyl (4,40-DIPB) should be facilitated over ordered
microporous materials if the catalytic sites are appropriately
restricted by steric hindrance in their channels. In previous pa-
pers, we have described that 4,40-DIPB is selectively produced
from BP over dealuminated H-mordenite, which has 12-
membered (12-MR) pore-entrance with straight channels.4–10
Shape-selective isopropylation of BP have also been described
over one-dimensional zeolites, ZSM-12,13 CIT-5,13–15 SSZ-
24,13,15,16 SAPO-5,17 MAPO-5 (M: Mg, Ca, Sr, Ba, and Zn),18
and SSZ-31.13,19 We have proposed that shape-selective iso-
propylation over these zeolites occurred by effective exclusion
of the transition states of bulkier DIPB isomers by the steric
restriction inside the channels, resulting in preferential forma-
tion of 4,40-DIPB.4–10,13–19 On the other hand, Takeuchi et al.
have reported that the isopropylation of BP over Y-zeolite af-
forded principally thermodynamically unstable DIPB isomers
with 2-isopropyl group at low temperatures and thermodynam-
ically stable isomers, 3,40-, 3,30-, and 4,40-DIPB at high tem-
peratures.20 Similar results were also obtained in the isopropyl-
ation over Beta and CIT-1 zeolites.21 These results indicate
that the isopropylation occurs under kinetic control at lower
temperatures and under thermodynamic control at high tem-
peratures because the channels of these zeolites are too large
for the selective formation of 4,40-DIPB.4–7
Alkylating agent is another important key for shape-
selective catalysis. Bulky alkylating agent increases the steric
restrictions on the transition states of bulky isomers inside the
y Present address: Department of Materials Science and Engi-
neering, Graduate School of Engineering, Yokohama National
University, Yokohama 240-8501
Published on the web November 13, 2007; doi:10.1246/bcsj.80.2232

Y. Sugi et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007) 2233
Table 1. Properties of Zeolites
External
surface
area
Pore
entrance
Surface
area
Pore
NH3-TPD
Acid
amount
Structure of
channel
Cage
volume peak temp.
(MR) SiO2/Al2O3 /m2 gꢃ1 /m2 gꢃ1a) /mL gꢃ1
Zeolite
FTC
/nm2
/ꢁC
389
/mmol gꢃ1
Straight with
8-MR side-pocket
Straight
Mordenite MOR 0:67 ꢂ 0:72
—
128
460
35
5.4
18
11
0.16
0.20
SSZ-24
SSZ-55
SSZ-42
AFI 0:72 ꢂ 0:72
ATS 0:65 ꢂ 0:75
IFR 0:62 ꢂ 0:72
—
20
24
202
160
280
414
478
518
0.16
0.19
0.20
274
299
255
0.11
0.12
0.08
Corrugated
Corrugated
a) Calculated by t-plot of N2 adsorption.
are summarized in Table 1.
channels and enhance the difference in bulkiness among the
isomers, resulting in preferential formation of the least
bulky isomers. There have been only a few papers involving
the influence of the alkylating agent on the alkylation of
BP.15,20,22–25 Horniakova et al. have described that the use of
2-methyl-2-propanol as alkylating agent afforded the high
selectivity for 4,40-di-t-butylbiphenyl (4,40-DTBB) in the t-
butylation over MOR, Y, and Beta zeolites.22–24 We also found
that the shape-selectivities in s-butylation and t-butylation oc-
curred over one-diemensional 14-MR zeolites: CIT-5, UTD-1,
and SSZ-53,15 and over three-dimensional 12-MR zeolites: Y,
ꢀ, and CIT-1.21
It is interesting to elucidate how the zeolite structures, par-
ticularly, dimensionality, pore-entrance, and channel structure,
are related to the shape-selective catalysis. In recent decades,
new types of 12-membered ring (12-MR) aluminosilicates
with different pore and channel structures have been syn-
thesized by many workers.14,16,26–39 SSZ-24 zeolite27–30 has
straight channels with pore-entrance of 0:72 nm ꢂ 0:72 nm.26
SSZ-5531–34 and SSZ-4235–39 zeolites have corrugated chan-
nels: 20-MR cavities with pore entrance of 0:65 nm ꢂ 0:75 nm
and 24-MR cavities with pore entrance of 0:62 nm ꢂ 0:72 nm,
respectively.26
In this paper, we describe the alkylation, i.e., isopropylation,
s-butylation, and t-butylation, of BP over one-dimensional 12-
MR zeolites, and discuss the influence of the selectivities for
dialkylbiphenyl (DABP) isomers on the structure of zeolite:
straight channels for Mordenite and SSZ-24 zeolites and corru-
gated channels for SSZ-55 and SSZ-42 zeolites. We also focus
on the influence of bulkiness of alkylating agents on the alkyl-
ation over these zeolites. The discussion in the paper was
based on the selectivity for DABP isomers to understand the
relationships between zeolite structure and alkylating agent
in shape-selective catalysis. The abbreviations of zeolites are
expressed by FTC from IZA Structure Commission: MOR
for Mordenite, AFI for SSZ-24, ATS for SSZ-55, and IFR
for SSZ-42,26 or as stated otherwise.
The Alkylation of BP. The alkylation of BP was carried out
in a 100-mL SUS-316 autoclave. Typical reaction conditions of
the isopropylation were: BP 7.71 g (50 mmol), the catalyst 0.25 g,
temperature 150–300 ꢁC, and period 4 h under 0.8 MPa of propene
pressure 0.8 MPa (0.4 MPa for 1-butene in the s-butylation and
for 2-methylpropene in the t-butylation). An autoclave containing
BP and the catalyst was purged with nitrogen and heated to reac-
tion temperature, and the reaction started by agitation after intro-
duction of propene into the autoclave. The pressure was main-
tained constant throughout the reaction. After cooling the auto-
clave to ambient temperature and careful release of excess
propene, the catalyst was separated from organic products by
filtration. The organic products were subjected to the analyses
by using a Gas Chromatograph GC-14A or GC-18A (Shimadzu
Corp., Kyoto) equipped with an Ultra-1 capillary column (25 m ꢂ
0:2 mm; Agilent Technologies Co., Ltd., MA, USA). The products
were also identified by using a Shimadzu Gas Chromatograph-
Mass Spectrometer GC-MS 5000.
Dialkylbiphenyl in the alkylation is generally expressed as
DABP: DIPB, DSBB, and DTBB for isopropylation, s-butylation,
and t-butylation, respectively.
The yields of each product in the alkylation of BP were calcu-
lated on the basis of the amount of starting BP, and the selectiv-
ities for each DABP isomer were determined based on total
amounts of DABP isomers, respectively.
Selectivity for a DABP isomer (%)
Each DABP isomer (mol)
¼
ꢂ 100:
ð1Þ
DABP isomers (mol)
The catalytic activities based on the yield of alkylates are sum-
marized in Figs. S1–S6 of the Supporting Information.
Analysis of the encapsulated products in the catalyst used for
the reaction was carried out as follows. The catalyst, separated
from organic products by filtration, was washed well with 200
mL of acetone, and dried at 110 ꢁC for 12 h. A 50-mg sample of
the resulting catalyst was carefully dissolved in 3 mL of aqueous
hydrofluoric acid (47%) at room temperature. This solution was
neutralized with solid potassium carbonate, and the organic layer
was extracted three times with 20 mL of dichloromethane. After
removal of the solvent in vacuo, the residue was again dissolved
in toluene (5 mL), and subjected to GC analysis according to the
same procedure as the analysis for bulk products.
Experimental
Zeolites. AFI, IFR, and ATS were synthesized according
to the literatures.30–32,35 MOR was obtained commercially from
Tosoh Corp., Tokyo, (SiO2/Al2O3 = 128; TSZ-690HOA). All
zeolites were used as H-form and calcined at 550–650 ꢁC before
the reaction.
The zeolites were characterized by FE-SEM, XRD, ICP,
N2 and o-xylene adsorption, NH3-TPD, and 11B, 27Al, and
29Si MAS NMR. Properties of the zeolites related to the catalysis
The Characterization of Catalysts. The crystal structure of
zeolites was determined by powder X-ray diffraction using a
Shimadzu XRD-6000 diffractometer with Cu Kꢁ radiation
˚
(ꢂ ¼ 1:5418 A). Elemental analysis of zeolites was performed by
using inductive coupled plasma atomic emission spectroscopy on

2234 Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007)
Alkylation of Biphenyl over 12-MR Zeolites
120
90
60
30
0
MOR
AFI
ATS
IFR
2
10
20
30
40
50
0
10
20
30
40
50
60
2θ /deg
Period /min
Fig. 1. XRD patterns of 12-MR zeolites used as catalysts.
Fig. 3. o-Xylene adsorption on zeolites: : MOR; : AFI;
: ATS; : IFR.
2µm
5µm
5µm
AFI
ATS
IFR
Fig. 2. SEM images of 12-MR zeolites (as-synthesized) used for the catalysis.
a JICP-PS-1000 UV spectrometer (Teledyne Leeman Labs, Inc.,
NH, USA). Crystal size and morphology of zeolites were deter-
mined on an S-4300 FE-SEM microscope (Hitachi Corp., Tokyo).
N2 adsorption measurements were carried out on a Belsorp 28SA
apparatus (Bel Japan, Inc., Osaka). The adsorption of o-xylene
was performed by gravimetric method with its vapor (0.48 kPa)
using a highly sensitive quartz microbalance at 120 ꢁC after the
evacuation at 550 ꢁC. Ammonia temperature programmed desorp-
tion (NH3-TPD) was measured by using a TPD-66 apparatus
(Bel Japan): the catalyst sample was evacuated at 400 ꢁC for
1 h, and ammonia was adsorbed at 100 ꢁC followed by further
evacuation for 1 h. Then, the sample was heated from room
temperature to 710 ꢁC at the rate of 10 ꢁC minꢃ1 in a helium flow.
11B, 27Al, and 29Si NMR spectra were recorded at room tempera-
ture under magic angle spinning (MAS) by using 7.0 mm diameter
zirconia rotors spinning at 4 kHz on an Inova 400 spectrometer
(Varian Corp., MA, USA).
IFR. Figure 2 shows typical SEM images of the as-synthesized
samples. XRD patterns and SEM images of these zeolites
agree with those in the literature.14,28–30,37–39
Substitution of B3þ in [B]-SSZ-42 and [B]-SSZ-55 with
Al3þ was carried out by using 1 M Al(NO3)3 aqueous solution
(1 M = 1 mol dmꢃ3) at 80 ꢁC according to the literature.15
XRD patterns after repeating the substitution three times were
almost the same as original calcined samples. The structure of
zeolites did not collapse during calcination, acid treatment, and
substitution of B3þ with Al3þ
.
N2 adsorption on MOR, AFI, ATS, and IFR exhibited a
typical type-I isotherm (Figure not shown). Their specific
surface area and pore volume were 410–520 m2 gꢃ1 and 0.16–
0.20 mL gꢃ1, respectively. These results indicate that MOR,
AFI, ATS, and IFR have typical microporous structures. Exter-
nal surface areas calculated from t-plot of N2 adsorption were
35, 5.4, 14, and 11 m2 gꢃ1 for MOR, AFI, ATS, and IFR.
Figure 3 shows the adsorption of o-xylene on MOR, AFI,
ATS, and IFR. The adsorption was saturated in short period
on all zeolites. The initial rates of the adsorptionꢃw1 ere in the
order: IFR (28.1 m2 gꢃ1 minꢃ1) > ATS (19.9 m2 g minꢃ1) ꢄ
MOR (19.0 m2 gꢃ1 minꢃ1) ꢄ AFI (17.7 m2 gꢃ1 minꢃ1). In
addition, the amounts of the adsorption were significantly
Results and Discussion
Properties of Zeolites. Typical physicochemical proper-
ties of the zeolites, MOR, AFI, ATS, and IFR, used for the
catalysis, are shown in Table 1. These properties agree with
those of the zeolites in the literature.14,16,26–39
Figure 1 shows the XRD patterns of MOR, AFI, ATS, and

Y. Sugi et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007) 2235
IFR
0.01 mol/m3
MOR
AFI
ATS
AFI
ATS
IFR
150
100
50
0
-50
-100
δ
/ppm
Fig. 4. 27Al MAS NMR spectra of 12-MR zeolites.
50 100
200
300
400
500
600
influenced by the types of zeolites in the order: IFR ꢅ
ATS ꢄ AFI > MOR. It means that their channels are large
enough for the diffusion of o-xylene in them. These results
of o-xylene adsorption are ascribed to the space in the channels
of zeolites: ATS and IFR have corrugated channels with 20-
MR and 24-MR cages and with pore-entrance of 0:65 nm ꢂ
0:75 nm and 0:62 nm ꢂ 0:72 nm, respectively; however,
MOR and AFI have straight channels with pore-entrance of
0:67 nm ꢂ 0:72 nm and 0:72 nm ꢂ 0:72 nm, respectively.26
These differences may reflect their catalytic properties in the
alkylation of BP.
27Al MAS NMR spectra of AFI, ATS, and IFR are shown
in Fig. 4. Peaks assigned to tetrahedral Al3þ species, which
are incorporated to zeolite framework, were observed at
around 50 ppm in all zeolites. Small octahedral Al3þ species,
which are not incorporated in the framework, appeared at
around 0 ppm after substitution of B3þ in the frameworks of
[B]-SSZ-42 and [B]-SSZ-55 with Al3þ. However, AFI synthe-
sized from [Al]-BEA as a precursor only had small peaks of
octahedral Al3þ species. Tetrahedral and octahedral Al3þ spe-
cies also appeared in the spectra of AFI prepared from [B]-
SSZ-24.16 Substitution of B3þ with Al3þ was also confirmed
in the 11B and 29Si MAS NMR spectra.
NH3-TPD profiles of MOR, AFI, ATS, and IFR are shown
in Fig. 5. They had l- and h-peaks in the range of around 150–
250 and 250–450 ꢁC, respectively. l-Peaks are due to physical
adsorption, and h-peaks correspond to Brønsted acidity by
Al3þ species incorporated in the zeolite framework judging
from the observation with 27Al MAS NMR. Acid amounts, cal-
culated from area of deconvoluted h-peak, reflect the SiO2/
Al2O3 ratios (see Table 1). The peak temperature of h-peak
was the highest for MOR and decreased in the order: MOR
(389 ꢁC) ꢅ ATS (294 ꢁC) > AFI (274 ꢁC) > IFR (255 ꢁC),
which corresponds to the order of acid strength (see Table 1).
AFI, ATS, and IFR have weaker acidities than MOR; particu-
larly, IFR has the lowest acidity among four zeolites. How-
ever, their acidities are enough for the acid catalysis, particu-
larly, alkylation of polynuclear aromatic hydrocarbons, such
as BP.
Temperature /°C
Fig. 5. NH3-TPD profiles of zeolites. Dotted lines: l- and
h-Peaks by the deconvolution.
The Isopropylation. Figure 6 shows the influence of reac-
tion temperature on the isopropylation of BP over MOR and
AFI. The selectivities for 4,40-DIPB were 90% over MOR
and 50–65% over AFI at low to moderate temperatures up to
275 ꢁC. Similar features of the selectivity for 4,40-DIPB were
observed over AFI prepared by the substitution of B3þ in
16
[B]-SSZ-24 with Al3þ
.
These results at moderate tempera-
tures mean that 4,40-DIPB is formed inside the channels
through shape-selective catalysis by ‘‘restricted transition state
selectivity mechanisms.’’1 Bulky DIPB isomers are preferen-
tially excluded from their channels by steric restriction, result-
ing in the selective formation of 4,40-DIPB as discussed previ-
ously.4–10 However, the selectivity for 4,40-DIPB over AFI was
lower than that over MOR at moderate temperatures, because
AFI has larger channels than MOR.
The selectivity in bulk products decreased to 30% at 300 ꢁC
accompanying the increase in the formation of 3,40- and 3,30-
DIPB as shown in Fig. 6. However, the selectivity for 4,40-
DIPB in encapsulated products over MOR was around 90%
in the range of 150–300 ꢁC. These results show that the de-
crease in the selectivity for 4,40-DIPB over MOR is due to
the isomerization of 4,40-DIPB at the external acid sites as dis-
cussed in the previous paper.4–10,40 On the other hand, the se-
lectivity for 4,40-DIPB in bulk products over AFI was 65–70%
up to 275 ꢁC and decreased to 30% at 300 ꢁC. The selectivity
for 4,40-DIPB in encapsulated products also decreased gradual-
ly from 70% at 250 ꢁC to 50% at 300 ꢁC. These results indicate
that 4,40-DIPB is isomerized at the acid sites, partly inside the
channels in addition to at the external surface. These differ-
ences in the isomerization of 4,40-DIPB between MOR and
AFI are due to the steric restriction in zeolite channels. AFI
can allow the accommodation of the transition states of the
bulkier DIPB isomers inside the channels, because its channels
are larger than those of MOR. However, there is another pos-
sibility that the decrease in steric restriction by AFI channels

2236 Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007)
Alkylation of Biphenyl over 12-MR Zeolites
AFI
MOR
100
100
80
60
40
20
0
80
60
40
20
0
150
200
250
300
150
200
250
300
Reaction temperature /°C
Fig. 6. The influence of reaction temperature on the isopropylation of BP over MOR and AFI. Reaction conditions: for MOR: BP,
30.84 g (200 mmol); catalyst, 1.0 g and for AFI: BP, 7.71 g (50 mmol); catalyst, 0.25 g; temperature, 150–300 ꢁC; propene pres-
sure, 0.8 MPa; period, 4 h. Legends: Bulk products. : 4,40-DIPB; : 3,40-DIPB; : 3,30-DIPB; : 2,x0-DIPB; : 3,5-DIPB;
: conversion. Encapsulated products. : 4,40-DIPB.
IFR
ATS
100
80
60
40
20
0
100
80
60
40
20
0
150
200
250
300
150
200
250
300
Reaction temperature /°C
Fig. 7. The influence of reaction temperature on the isopropylation of BP over ATS and IFR zeolites. Reaction conditions: for ATS:
BP, 7.71 g (50 mmol); catalyst, 0.25 g and for IFR: 3.86 g (25 mmol); catalyst, 0.125 g; temperature, 150–300 ꢁC; propene pressure,
0.8 MPa; period, 4 h. Legends: see Fig. 6.
causes the decease in the selectivity for 4,40-DIPB at high
temperatures. Isomerization of 4,40-DIPB inside the channels
was also observed for MAPO-5 (M: Mg and Zn) with AFI
topology18 and for CIT-5 with CFI topology.13–15
Figure 7 shows the influence of reaction temperature on the
isopropylation of BP over ATS and IFR. The selectivities for
4,40-DIPB over ATS and IFR were much lower than those over
MOR and AFI. The selectivity for 4,40-DIPB was only 23% at
150 ꢁC to 15% at 300 ꢁC over ATS and 35% at 150 ꢁC to 28%
at 300 ꢁC over IFR. The principal products over ATS and IFR
were bulky DIPB isomers, 2,x0-DIPB (2,20-, 2,30- and 2,40-
DIPB) and 3,40-DIPB, and the selectivity for 2,x0-DIPB de-
creased at higher temperatures, accompanied by an increase
in the selectivity for 3,40-DIPB. These high selectivities for
2,x0-DIPB and 3,40-DIPB resemble the isopropylation of BP
over FAU, BEA, and CON.20,21 The low selectivities for
4,40-DIPB over these zeolites are due to loose steric restriction
on the transition states of bulky DIPB isomers in corrugated
channels: the formation of bulky 2,x0-DIPB is allowed inside
the channels, resulting in the low selectivity for 4,40-DIPB.
Over these zeolites, the increase in the reaction temperature
caused the decrease in the selectivity for 2,x0-DIPB and the

Y. Sugi et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007) 2237
MOR
AFI
100
80
60
40
20
0
100
80
60
40
20
0
150
200
250
300
150
200
250
300
Reaction temperature /°C
Fig. 8. The influences of reaction temperature on the s-butylation of BP over MOR and AFI. Reaction conditions: for MOR: BP,
7.71 g (50 mmol); catalyst, 0.25 g and for AFI: BP, 3.86 g (25 mmol). catalyst, 0.125 g; temperature, 150–300 ꢁC; 1-butene pres-
sure, 0.5 MPa; period, 4 h. Legends: Bulk products. : 4,40-DSBB; : 3,40-DSBB; : 3,30-DSBB; : 2,x0-DSBB; : conversion.
Encapsulated products. : 4,40-DSBB.
increase in the selectivity for 3,40- and 3,30-DIPB. These re-
sults suggest that the formation of 2,x0-DIPB over ATS and
IFR is kinetically controlled at lower temperatures, because
of the predominant nucleophilic attack of alkylating agent at
the 2-position of BP, which has a high electron density; how-
ever, the decrease in the selectivity for 2,x0-DIPB was accom-
panied by an increase in the selectivity for thermodynamically
stable 3,40- and 3,30-DIPB with an increase in the temperature.
The selectivities for 4,40-DIPB in encapsulated products
in the isopropylation over ATS and IFR are also shown in
Fig. 7. They were 20–30% for ATS and IFR: these values were
almost constant at all temperatures. These results strongly in-
dicate that low selectivities for 4,40-DIPB over ATS and IFR
are due to kinetic and thermodynamic control in the catalysis,
and not to the isomerization of 4,40-DIPB formed shape-selec-
tively inside the channels.
The selectivities for 4,40-DIPB over SSZ-24 zeolites were
on the same level as those over SAPO-5 and MAPO-5 (M:
Mg, Ca, Sr, and Zn) in the isopropylation of BP.17,18 SSZ-55
and MAPO-36 (M: Mg and Zn) also gave similar level of
the selectivities for 4,40-DIPB.41,42 These results show that
the selectivities by the zeolites with AFI and ATS topologies
do not depend on the type of metals, but on the type of frame-
work.
The s-Butylation. Figure 8 summarizes the influence of
reaction temperature on the s-butylation of BP over MOR
and AFI. The selectivities for 4,40-di-s-butylbiphenyl (4,40-
DSBB) among DSBB isomers were enhanced significantly
compared to those in the isopropylation. The selectivities for
4,40-DSBB were higher than 95% over MOR and 90% over
AFI at low and moderate temperatures below 250 ꢁC. The
selectivities for 4,40-DSBB in the s-butylation were higher
than those for 4,40-DIPB in the isopropylation. Although the
effective molecular diameter of DSBB isomers is almost the
same as that of DIPB isomers, the replacement of isopropyl
groups with the s-butyl groups in 3,40- and 4,40-DABP causes
the differences in bulkiness of both DABP isomers at the inter-
action of the transition states with the channels. These syner-
getic effects enhance the shape-selectivities for 4,40-DSBB
over MOR and AFI by replacement of isopropyl group with
s-butyl group.
Figure 9 shows the influence of reaction temperature on
the s-butylation of BP over ATS and IFR. The selectivities
for 4,40-DSBB were 70% over ATS and 50% over IFR at
250 ꢁC, and they were much higher than those for 4,40-DIPB
in the isopropylation. These results indicate that shape-selec-
tive natures appeared in the s-butylation even over corrugated
ATS and IFR channels, although they are less effective than
those over MOR and AFI. s-Butyl moieties of DSSB isomers
may exclude more effectively the transition states leading to
bulky isomers, such as 3,40-DSBB, by steric restriction in
ATS and IFR channels. The selectivities for 4,40-DSBB over
ATS were higher than those over IFR. ATS makes easier to
exclude the bulkier isomers at their transition states than
IFR, because ATS have smaller reaction space than IFR. A
decrease in the selectivity for 2,x0-DSBB occurred over ATS
and IFR at high temperatures accompanying the formation of
3,40-DSBB: this is due to the participation of kinetic control
to yield predominantly 2,x0-DIPB at lower temperatures
and of thermodynamic control to yield 3,40-DIPB at higher
temperatures.
The selectivities for 4,40-DSBB in bulk products decreased
at high temperatures in the range of 250–300 ꢁC in the s-butyl-
ation in Fig. 8 for MOR and AFI and in Fig. 9 for ATS and
IFR. However, the selectivities for 4,40-DSBB in encapsulated
products remained high over these zeolites. These results mean
that these decreases are due to the isomerization of 4,40-DSBB
at external acid sites, which cannot occur inside the channels
as discussed in the isopropylation.4–10 The channels of these
zeolites are too small for the isomerization of 4,40-DSBB.

2238 Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007)
Alkylation of Biphenyl over 12-MR Zeolites
ATS
IFR
100
100
80
60
40
20
0
80
60
40
20
0
150
200
250
300
150
200
250
300
Reaction temperature /°C
Fig. 9. The influences of reaction temperature on the s-butylation of BP over ATS and IFR. Reaction conditions. 3.86 g (25 mmol);
catalyst, 0.125 g; temperature, 150–300 ꢁC; 1-butene pressure, 0.5 MPa; period, 4 h. Legends: see Fig. 8.
MOR
AFI
100
80
60
40
20
0
100
80
60
40
20
0
150
200
250
300
150
200
250
300
Reaction temperature /°C
Fig. 10. The influences of reaction temperature on the t-butylation of BP over MOR and AFI. Reaction conditions: for MOR: BP,
7.71 g (50 mmol); catalyst, 0.25 g and for AFI: BP, 3.86 g (25 mmol); catalyst, 0.125 g; temperature: 150–300 ꢁC; 2-methylpropene
pressure, 0.5 MPa; period: 4 h. Legends. Bulk products: : 4,40-DTBB; : 3,40-DTBB; : 3,30-DTBB; : 2,x0-DTBB; : con-
version. Encapsulated products: : 4,40-DTBB.
On the other hand, there were no significant changes in the se-
lectivity for 4,40-DSBB in bulk and encapsulated products over
IFR. This may be due to low acidities of IFR judging from
NH3-TPD.
The t-Butylation. The influence of reaction temperature
on the t-butylation of BP is shown in Fig. 10 for MOR and
AFI and in Fig. 11 for ATS and IFR. Shape-selective forma-
tion of 4,40-DTBB was observed over these zeolites at low and
moderate temperatures, and the selectivities for 4,40-DTBB at
250 ꢁC were higher than those for 4,40-DIPB and 4,40-DSBB in
isopropylation and s-butylation: 95% over MOR and AFI, 90%
over ATS, and 80% over IFR. These results shows the chan-
nels of these zeolites can differentiate 4,40-DTBB from other
bulky isomers at the transition states. However, the less
selective formation of 4,40-DTBB over ATS and IFR is due
to loose steric restriction on the transition states of the bulky
isomers inside their channels. Particularly, the large IFR chan-
nels allow the formation of bulkier 3,40-DTBB.
The selectivities for 4,40-DTBB in encapsulated DTBB
isomers in the t-butylation over these zeolites remained high
in the range of 150–250 ꢁC as shown in Figs. 10 and 11:
95–98% over MOR and AFI, and 85–93% over ATS, and
75–83% over IFR. However, the selectivities for 4,40-DTBB
in bulk products were significantly lowered at 300 ꢁC over

Y. Sugi et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007) 2239
ATS
IFR
100
80
60
40
20
0
100
80
60
40
20
0
150
200
250
300
150
200
250
300
Reaction temperature /°C
Fig. 11. The influences of reaction temperature on the s-butylation of BP over ATS and IFR. Reaction conditions: BP, 3.86 g
(25 mmol); catalyst, 0.125 g.; temperature, 150–300 ꢁC; 2-methylpropene pressure, 0.5 MPa; period, 4 h. Legends: see Fig. 10.
MOR, AFI, and ATS: 30% over MOR and ATS, and 50% over
AFI. The differences in the selectivities for 4,40-DTBB be-
tween bulk and encapsulated products over MOR, AFI, and
ATS indicate that the isomerization of 4,40-DTBB occurs at
the external acid sites because the channels of these zeolites
are too small for the isomerization of 4,40-DTBB. On the other
hand, no significant change in the selectivities for 4,40-DTBB
occurred over IFR: the external acid sites of IFR are less active
in the catalysis compared to those of the other zeolites, be-
cause of the low acidity discussed in the s-butylation.
Decreases in the conversion of BP were observed in the
t-butylation over MOR and AFI, accompanied by decreases
in the yield of DTBB isomers (see Fig. S5 in the Supporting
Information). These decreases are due to the de-alkylation of
DTBB isomers at the higher temperatures.
bulky isomer by the shape-selective catalysis, 3,x0-DABP
(3,40- and 3,30-) for the thermodynamically stable and bulky
isomers formed principally under thermodynamic control,
and 2,x0-DABP (2,20-, 2,30-, and 2,40-) for the bulky and
thermodynamically unstable isomers formed principally under
kinetic control. The selectivities for 4,40-, 3,x0-, and 2,x0-DABP
highly depended on the type of zeolites and alkylating agents.
Particularly, the selectivities for 4,40-DABP decreased with an
increase in the reaction spaces in the zeolites and increased
with an increase in bulkiness of the alkylating agents. The
selectivities for 3,x0- and 2,x0-DABP were also influenced by
reaction temperatures in addition to type of zeolites and alkyl-
ating agents as discussed in the previous sections. The selectiv-
ities for 4,40-DABP in encapsulated products at 250 ꢁC were
similar to those in bulk products, as shown in Fig. 12.
The Influence of Zeolite Structure and Alkylating Agent.
MOR, AFI, ATS, and IFR are one-dimensional zeolites with
12-MR pore-entrances, although they have different types of
channels. MOR and AFI have straight channels with pore-
entrance of 0:67 nm ꢂ 0:72 nm and 0:73 nm ꢂ 0:73 nm, re-
spectively.26 ATS and IFR have corrugated channels: 20-MR
cavities with pore entrance of 0:65 nm ꢂ 0:75 nm and 24-MR
cavities with pore entrance of 0:62 nm ꢂ 0:72 nm, respective-
ly. (see also in Fig. S7 in the Supporting Information).26 The
features indicate that the reaction space inside channels is
in the order: MOR < AFI ꢆ ATS < IFR, and consequently,
that the steric restriction in the channels decreases in the order:
MOR > AFI ꢅ ATS > IFR. These differences reflect the
exclusion of bulky DABP isomers from the channels.
Figure 12 shows the selectivities for DABP isomers in
bulk products and for 4,40-dialkylbiphenyl (4,40-DABP) in
encapsulated products in the alkylation of BP over MOR,
AFI, ATS, and IFR at 250 ꢁC. They were typical selectivities
in relation to the zeolite structure, because further iso-
merization of 4,40-DABP are almost negligible over these
zeolites at 250 ꢁC. The products from the alkylation of BP
are classified into three categories: 4,40-DABP for the least
Shape-selective isopropylation of BP, which means the pref-
erential formation of the least bulky 4,40-DIPB by the exclu-
sion of bulky DIPB isomers due to the steric restriction of
the transition states, occurred only over MOR and AFI with
straight channels. The lower selectivity for 4,40-DIPB of AFI
compared to that of MOR is due to the loose restriction of
AFI channels compared to that of MOR. On the other hand,
ATS and IFR with corrugated channels gave 4,40-DIPB only
with a low selectivity, accompanying bulkier isomers, 2,x0-
and 3,x0-DIPB. The large spaces in the channels of ATS and
IFR compared to those of MOR and AFI can allow the forma-
tion of bulky isomers in their channels. These high selectivities
for 2,x0-DIPB and 3,x0-DIPB resemble the isopropylation
over FAU, BEA, and CON.20,21 Isopropylation under sterically
less restricted conditions in zeolite channels is controlled
kinetically at low temperatures to yield 2,x0-DIPB isomers,
because of preferential nucleophilic attack of alkylating agent
at 2-position with high electron density. However, the thermo-
dynamic factors contribute to the catalysis at high tempera-
tures, resulting in the enhancement of stable isomers, 3,x0-
DIPB, particularly, 3,40-DIPB.
The s-butylation gave the high selectivities for 4,40-DSBB

2240 Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007)
Alkylation of Biphenyl over 12-MR Zeolites
Isopropylation
s-Butylation
t-Butylation
100
100
80
60
40
20
0
80
60
40
20
0
MOR AFI
ATS
IFR MOR AFI
ATS
IFR MOR AFI
ATS
IFR
Fig. 12. The selectivity for DABP isomers in the alkylation of BP over the zeolites. Reaction conditions: temperature: 250 ꢁC.
Other conditions: see Figs. 6–11. Legends
: 4,40-DABP;
: 3,x0-DABP (3,40-, 3,30-, and 3,5-);
: 2,x0- DABP (2,20-, 2,30-,
and 2,40-); : 4,40-DABP in encapsulated products.
over MOR and AFI at 250 ꢁC: 95% over MOR and 85% over
AFI. The selectivities for 4,40-DSBB were higher than those
for 4,40-DIPB in the isopropylation. They were also enhanced
in the s-butylation over ATS and IFR: 75% over ATS and 50%
over IFR. Although ATS and IFR channels are corrugated,
they effectively exclude the bulky isomers in the s-butylation,
resulting in the selective formation of 4,40-DSBB. The differ-
ences in the selectivities for 4,40-DSBB are due to the steric
restriction of bulky isomers among the zeolites as discussed
above. The lower selectivities for 4,40-DSBB over IFR com-
pared to those over ATS are due to the difference of corrugated
channels: 20-MR cages for ATS and 24-MR cages for IFR.26
The s-butylation over ATS and IFR was still controlled kineti-
cally at low temperatures and thermodynamically at higher
temperatures. The selectivities for 4,40-DSBB over ATS and
IFR were higher than those over DON with straight 14-MR
channels and SFH with corrugated 14-MR channels.15
Shape-selective formation of 4,40-DTBB was observed in
the t-butylation over all zeolites. The selectivities for 4,40-
DTBB were over 90% over MOR and AFI at 250 ꢁC. As well,
ATS and IFR afforded high selectivities for 4,40-DTBB: 85%
over ATS and 80% over IFR. These results mean that the steric
restriction of transition states in the channels decreased in
the order: MOR ꢇ AFI > ATS > IFR, as discussed on the s-
butylation.
The selectivities for DABP isomers over a zeolite were in-
fluenced by the bulkiness of alkylation agents. Highly shape-
selective formation of 4,40-DABP was observed over MOR
and AFI in all alkylations. The alkylation over ATS and IFR
with corrugated channels was influenced by the types of alkyl-
ating agent: the selectivities for 4,40-DIPB in the isopropyla-
tion were 20% over ATS and 30% over IFR at 250 ꢁC, and
higher selectivities for 4,40-DSBB were obtained: 70% over
ATS and 50% over IFR. Moreover, the selective formation
of 4,40-DTBB occurred in the t-butylation over these zeolites.
The bulkiness of alkylating agent enhances the steric interac-
tion of the transition states of DABP isomers with channels.
Moreover, the replacement of isopropyl groups with the bulky
groups in 3,40- and 4,40-DABP causes the differences in bulki-
ness of both DABP isomers and in the interaction of their tran-
sition states with the channels. These synergetic effects en-
hance the shape-selectivities with increasing the bulkiness of
alkylating agents. The channels of ATS and IFR are too large
for the selective formation of 4,40-DIPB in the isopropylation;
however, shape-selective natures appeared in s-butylation and
t-butylation over these zeolites. Kinetic control at low temper-
atures and thermodynamic control at high temperatures con-
tribute principally to the isopropylation, yielding 2,x0- and
3,x0-DIPB as principal products, respectively. However, the
exclusion of the bulky DSBB isomers occurred even inside
large ATS and IFR channels in s-butylation by using 1-butene,
resulting in the increasing the selectivities for 4,40-DSBB.
Further, 4,40-DTBB were effectively differentiated from bulky
DTBB isomers by the channels of these zeolites in the t-butyl-
ation. The similar influence of alkylating agents on the selec-
tivities for 4,40-DABP were observed for one-dimensional 14-
MR zeolites,15 and three-dimensional 12-MR zeolites,21 which
have large reaction space in their channels. These results
indicate that the shape-selective catalysis occurs through the
differentiation of the least bulky isomer from the other isomers
in the transition states by steric restriction inside the channels.
‘‘Product selectivity mechanism,’’1 in which the least bulky
isomers predominantly diffuse out from the mixtures inside
the channels, does not occur in these alkylation, because the
selective formation of 4,40-DABP was accompanied by their
high selectivities in the encapsulated products.
We have found the shape-selective formation of 4,40-DIPB
in the isopropylation of BP over several one-dimensional 12-
MR zeolites with straight channels: ZSM-12,13 and SSZ-3119
zeolites as well as MOR and SSZ-24 zeolites. Highly selective
formation of 4,40-DABP has also been observed in the s-butyl-
ation and the t-butylation over SSZ-3119 as well as over SSZ-
24. Particularly, 4,40-DSBB and 4,40-DTBB were selectively
obtained over SSZ-24 and SSZ-31 zeolites, which have the
largest channels among 12-MR zeolites.
The selectivities for 4,40-DIPB over SSZ-24 were in the
same level as those over SAPO-5 and MAPO-5 (M: Mg, Ca,
Sr, and Zn) in isopropylation, s-butylation, and t-butylation
of BP.17,18 Similar results were obtained in the isopropylation
over SSZ-55 and MAPO-36 (Mg: Mg and Zn).41,42 These

Y. Sugi et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 11 (2007) 2241
results show that the selectivities over the zeolites with AFI
and ATS topologies do not depend on the type of metals,
but on the type of their framework.
channels, such as ATS and IFR, can have shape-selective
nature if the bulky moieties, such as s-butyl and t-butyl groups,
are large enough to differentiate the transition state of the least
bulky DABP from other isomers inside their channels.
The selectivities for 4,40-DABP decreased at high tempera-
tures in some alkylations. These decreases are due to the iso-
merization of 4,40-DABP, because the channels are not large
enough for the isomerization of 4,40-DABP to bulkier 3,40-
DABP.
Among one-dimensional 14-MR zeolites, CFI yields 4,40-
DIPB shape-selectively in the isopropylation of BP.13–15 How-
ever, the predominant DIPB isomers are 2,x0-DIPB with 2-
isopropyl group over DON and SFH, and the selectivities for
4,40-DIPB are 10–15% in both bulk and encapsulated prod-
ucts.15 The selectivities for 4,40-DSBB and 4,40-DTBB were
enhanced by using bulky alkylating agent, 1-butene and 2-
methylpropene, respectively.15 Particularly, 4,40-DTBB was
obtained selectively in the t-butylation over all zeolites. These
differences are due to reaction spaces in the channels by the
types of zeolites and to alkylating agents as discussed for
12-MR zeolites in this study.
The selectivity for 4,40-DABP in bulk products decreased
with an increase in the temperatures in some alkylations: iso-
propylation over MOR, and s-butylation and t-butylation over
MOR, AFI, and ATS. However, the selectivities for 4,40-
DABP in encapsulated products remained high in the alkyla-
tion even at the high temperatures as 300 ꢁC. These results sug-
gest that the decreases in the selectivity for 4,40-DABP are
caused by the isomerization of 4,40-DABP to 3,40-DABP at
the external acid sites, because the channels are too small
for the isomerization of 4,40-DABP as discussed for the isopro-
pylation of BP over MOR.4–10 On the other hand, the selectiv-
ities for 4,40-DIPB both in bulk and encapsulated products in
the isopropylation over AFI decreased with an increase in
temperature: this is due to the channels being large enough
for the isomerization of 4,40-DIPB.
A part of this work was financially supported by a Grant-
in-Aid for Scientific Research (B) No. 16310056, 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 Founda-
tion (KOSEF; Grant No. F01-2004-000-10510-0).
Supporting Information
Figures S1–S6: The influence of yields of alkylates on the al-
kylation of BP over MOR, AFI, ATS, and IFR. Figure S7: Models
for channels of zeolites. This material is available free of charge
on the web at http://www.csj.jp/journals/bcsj.
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