Highly selective catalytic hydroconversion of benzyloxybenzene to bicyclic cyclanes over bifunctional nickel catalysts

Article abstract of DOI:10.1016/j.catcom.2017.04.042

An active bifunctional nickel catalyst was prepared by decomposing Ni(CO)₄ to highly dispersed metallic Ni onto Hβ zeolite and first applied in hydroconverting benzyloxybenzene (BOB), which was used as a lignin-related model compound. Ni/Hβ proved to be effective for converting BOB to bicyclic cyclanes (BCCs) via C_alk–O bond cleavage induced by H⁺ addition, benzylium addition to 2- and 4-positions in phenol, hydrogenation of benzene ring, dehydration, and H^? abstraction. Compared to one-step conversion, the total BCC selectivity (TBCCS) significantly increases from catalytic hydroconversion of catalytically converted BOB by pretreatment under pressurized N₂.

Full text of DOI:10.1016/j.catcom.2017.04.042

Accepted Manuscript
Highly selective catalytic hydroconversion of benzyloxybenzene
to bicyclic cycloalkanes over bifunctional nickel catalysts
Xiao Zhou, Xian-Yong Wei, Zhong-Qiu Liu, Jing-Hui Lv, Yue-
Lun Wang, Zhan-Ku Li, Zhi-Min Zong
PII:
DOI:
Reference:
S1566-7367(17)30176-0
doi: 10.1016/j.catcom.2017.04.042
CATCOM 5027
To appear in:
Catalysis Communications
Received date:
Revised date:
Accepted date:
10 December 2016
15 April 2017
23 April 2017
Please cite this article as: Xiao Zhou, Xian-Yong Wei, Zhong-Qiu Liu, Jing-Hui Lv, Yue-
Lun Wang, Zhan-Ku Li, Zhi-Min Zong , Highly selective catalytic hydroconversion of
benzyloxybenzene to bicyclic cycloalkanes over bifunctional nickel catalysts. The address
for the corresponding author was captured as affiliation for all authors. Please check if
appropriate. Catcom(2017), doi: 10.1016/j.catcom.2017.04.042
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ACCEPTED MANUSCRIPT
Highly selective catalytic hydroconversion of benzyloxybenzene to bicyclic
cycloalkanes over bifunctional nickel catalysts
Xiao Zhou, Xian-Yong Wei, Zhong-Qiu Liu, Jing-Hui Lv, Yue-Lun Wang, Zhan-Ku Li, Zhi-Min
Zong
Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education, China
University of Mining & Technology, Xuzhou 221116, Jiangsu, China
 Corresponding author. Tel: +86 516 83885951; fax: +86 516 83884399.
E-mail address: wei_xianyong@163.com (X. Y. Wei)

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ABSTRACT
An active bifunctional nickel catalyst was prepared by decomposing Ni(CO)4 to highly dispersed
metallic Ni onto H zeolite and first applied in hydroconversion of benzyloxybenzene (BOB),
which was used as a lignin model compound. Ni/H was found to be effective for converting BOB
into bicyclic cycloalkanes via Calk-O bond cleavage induced by H+ addition, benzylium addition to
2- and 4-positions in phenol, hydrogenation of benzene ring, dehydration, and H- abstraction.
Compared to one-step conversion, the conversion of BOB was pretreated under N2 atmosphere and
then proceeded under H2 atmosphere and a much higher selectivity of bicyclic cycloalkanes is
obtained.
Keywords: Nickel; Benzyloxybenzene; Bicyclic cycloalkanes; Hydroconversion

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1. Introduction
Lignin, a main constituent of lignocellulosic biomass (15–30% by weight, 40% by energy), has
been a promising raw material for obtaining high-grade hydrocarbon fuels in view of its inherent
phenylpropane based structure [1,2]. The catalytic treatments of lignin or lignin oligomers [3-8],
especially catalytic hydroconversion (CHC) [9-12], have been extensively studied with the aim of
producing fuel range hydrocarbons.
Due to the structural complexity of lignin, insight into the reactions of model compounds has
become a powerful approach for elucidating the mechanism of CHC [13-21]. The CHC of
benzyloxybenzene (BOB) representing -O-4 linkages in lignin has been extensively investigated
o
[11,17-21]. Zhao et al. examined CHC of BOB over Ni/HZSM-5 at 250 C under 5 MPa of H2.
They found that BOB was selectively converted to monocyclic cycloalkanes (MCCs) with a yield of
more than 98% and bicyclic cycloalkanes (BCCs) accounting for less than 2% [11]. Chen et al.
investigated CHC of BOB in pseudo-homogeneous systems, i. e., uniformly stabilized noble metal
o
nanoparticles in ionic liquids, at 130 C under 5 MPa of H2 for 10 h. They found that cyclohexane
(CH) and methylcyclohexane (MCH) were the main products with a small amount of BCCs [17].
Güvenatam et al. reported their investigation on aqueous phase CHC of BOB using noble metal
o
catalysts (Pt, Pd, and Ru) at 200 C under acidic conditions. Their results showed that the reaction
predominantly yielded CH and MCH and the selectivity of BCCs was low [20]. The above CHC
processes are accompanied by catalytic cleavage of C-O ether bonds, which results in the
conversion of BOB into MCCs. These MCCs usually have a moderate value in fuel utilization [12].
Even though high value BCCs could be generated via two-step CHC of BOB [22], it requires two

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specific catalysts which will increase the cost. However, to our knowledge, no reports have been
issued on the CHC of BOB to high value BCCs on a sole catalyst and the bifunctional nickel
catalysts prepared from Ni(CO)4 is rarely applied in CHC of BOB.
In the present study, we report a highly active bifunctional nickel catalyst, prepared by
decomposing Ni(CO)4 to highly dispersed metallic Ni onto H zeolite, for converting BOB under
mild conditions to BCCs in n-hexane with high selectivity for the first time. The reaction route to
BCCs may be useful to selectively produce high value jet fuels.
2. Experimental
2.1. Catalyst preparation
Ni(CO)4 was synthesized by reacting Ni powder with CO under 6.0MPa at 100 °C in a 100 mL
stainless steel and magnetically stirred autoclave. All the 10 wt% Ni-based catalysts were prepared
by dispersing 2 g of the catalyst support (activated carbon (AC), HZSM-5, H, and HY) into a
mixture of 30 mL diethyl ether and 1 ml Ni(CO)4 in the autoclave. After replacing air inside the
autoclave with N2 for three times, the mixture was stirred for 1 h at room temperature, and then the
o
autoclave was heated to 100 C and kept at the temperature for 1 h to allow dispersing of metallic
Ni onto the support.
2.2. Catalyst characterizations
X-ray diffractometer (XRD) measurement was carried out with a Bruker Advance D8 XRD
equipped with a Cu Kα source (λ=1.5406Å). N2 adsorption-desorption isotherms were recorded by
nitrogen adsorption at 77 K with an Autosorb-1-MP apparatus and the pore size distribution was
calculated by the DFT method. Transmission electron microscope (TEM) analysis was performed
with a JEM-1011 microscope. NH3 temperature-programmed desorption (TPD) was performed on a

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TP-5000 type multi-function adsorption instrument. X-ray photoelectron spectra (XPS) were taken
on a Thermo Fisher Scientific K-Alpha 1063 spectrophotometer with the Al K radiation and the
beam spot size of 900 m (energy step size 1.000 eV, pass energy 50.0 eV). Accurate binding
energies could be determined by referring to the C 1s peak at 284.8 eV.
2.3. Catalytic reaction
In a typical run, 0.1 g BOB, 0.05 g catalyst, and 10 mL n-hexane were fed into a 60 mL stainless
steel and magnetically stirred autoclave. After replacing air in the autoclave and pressurizing with
H2 or N2 to 4 MPa at room temperature, the autoclave was heated to 160 oC followed by maintained
o
at 160 C for a prescribed period of time. Alternatively, the conversion of BOB was pretreated
under N2 atmosphere at 160 oC for 10 min and then proceeded under H2 atmosphere at 160 oC for 2
h in the same autoclave mentioned above. The reaction mixture was taken out of the autoclave and
filtrated after cooling the autoclave to the room temperature. The filtrate was identified with an
Agilent 7890/5975 gas chromatograph/mass spectrometer. The quantification was performed with
an Agilent 7890 gas chromatograph using n-decane as the external standard.
3. Results and Discussion
3.1. CHC of BOB
It is well-known that the catalyst supports play an essential role in governing product distribution
[23], and thereby it is crucial to select a suitable support when preparing an active CHC catalyst.
The catalytic performances of Ni-based catalysts with different supports were compared in CHC of
BOB under mild condition (160 oC, 4 MPa of H2, and 2 h), and the results are listed in Table 1. The
high conversion of BOB (95.5%) and the low selectivity of cycloalkanes (29.9%) are achieved over
Ni/AC. For Ni/HZSM-5, both the conversion of BOB and the selectivity of cycloalkanes are low.

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Ni/HY presents the low selectivity of cycloalkanes, which is similar to Ni/AC and Ni/HZSM-5.
Comparatively, the high conversion of BOB (100%) and the high selectivity of cycloalkanes
(93.0%) are achieved over Ni/H, indicating the superior catalytic performance in CHC of BOB. It
is noteworthy that BCCs appear in the products over Ni/Hand Ni/HY and the highest selectivity
of BCCs (68.3%) is obtained over Ni/H. The excellent selectivity of BCCs is disclosed for the first
time in one-step CHC of BOB.
Taking catalytic performance into account, Ni10%/Hwas chosen to study the effect of different
periods of reaction time. As Table 2 displays, the Ni/H-catalyzed converting of BOB is very fast.
The conversion is 80.1% after 10 min and the conversion is complete after 30 min. As reaction time
is extended, the selectivity of CH and MCH rises slightly, while the selectivity of phenol and
toluene declines slowly, indicating that the latter two act as intermediates and are converted into the
former two during this CHC process. Meanwhile, the selectivity of dicyclohexylmethane (DCHM)
and cyclopentylethylcyclohexane (CPEC) increases noticeably, while the selectivity of
2-benzylphenol (2-BPH) and 4-benzylphenol (4-BPH) decreases obviously, also indicating that the
latter two are converted into the former two during this CHC process. Moreover, the selectivity of
DCHM and CPEC as BCCs rises much faster than that of CH and MCH as MCCs and the highest
selectivity of BCCs is obtained after 90 min.
3.2. Catalyst characterizations
As illustrated in Table S1 and Fig. S1, HY has the largest specific surface area (SSA) and a
relatively low total pore volume (TPV), the SSA and TPV of AC and HZSM-5 are low, whereas H
presents a high SSA and the highest TPV. The three zeolites show the ordered pore structure and the
pore size is mainly in the range of 0-2.0 nm and slightly in the range of 2.0-4.0 nm, demonstrating

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the presence of a large portion of the micropores along with a little amount of mesopores, whereas
the pore size distributions of AC is broad and it demonstrates relatively more micropores. H and
Ni10%/H exhibit the similar shape of N2 adsorption–desorption isotherm and pore size distribution,
indicating that the textural property of H is largely preserved after impregnation. The SSA of H
falls down from 534 to 502 m2 g-1 and the TPV decreases from 0.45 to 0.41 cm3g-1 after supporting
metallic Ni. These may be due to the blocking of the microchannels by part of Ni species or the 10%
less H present in Ni10%/H. The similar results are also obtained over other supported Ni-based
catalysts.
As XRD patterns presented in Fig. 1, the characteristic diffraction peaks are observed for all the
catalysts at 2θ =44.5o, 51.8o, and 76.4o, corresponding to the (111), (200), and (220)
crystallographic planes of face centered cubic Ni phase, respectively [24]. The intensity in the
diffraction pattern of Ni10%/His very weak, indicating the high dispersion of Ni species on the
Hsurface. The diameter of Ni (111) is calculated from the Scherrer equation as 18.6 nm, based on
the XRD patterns of Ni10%/H.
As TEM images shown in Fig. S2, Ni particles dispersed uniformly on the H in the
Ni10%/Himage. Analysis of this Ni fraction showed that the average Ni particle size is 19 nm as
determined by transmission electron microscopy, which is quite consistent with the analysis with
XRD.
As Fig. 2 exhibits, C, Si, Al, Ni, and O exist in Ni10%/H. The principal peaks in the range of
846-866 eV are attributed to Ni 2p3/2. Among them, the peak at 861.4 eV is the satellite peak of NiO
and the peak at 852.4 eV is assigned to metallic Ni, while the other 2 peaks at 856.0 and 854.4 eV
denote the chemical bonds of NiO interacting strongly with the support and NiO dispersed on the

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support [25], respectively. The existence of NiO species could be due to the easy oxidation of
metallic Ni, which inevitably contacts with the air during the sample preparation and settlement.
Furthermore, XPS of Ni/HZSM-5, Ni/HY, and Ni/AC were also investigated. As Fig. S3
demonstrates, the existence of Ni species in Ni/HZSM-5, Ni/HY, and Ni/AC is similar with that in
Ni/H. In comparison with the binding energy (BE) of metallic Ni in pure Ni powder [26] and
Ni/AC (853.1 eV), the BE of metallic Ni in Ni/H negatively shifted by 0.7 eV. According to the
law of chemical shift, partial electron might transfer from H to metallic Ni, leading to Ni slightly
electron-enriched, which agreed with earlier investigation [27]. Generally, the adsorption of C=C
group on the Ni catalyst follows a d-π feedback mechanism and such electronic modifications
would be favorable for the electron-donation to π∗-orbital and weaken the strength of C=C bond
[26], which could facilitate the hydrogenation of C=C group [26,28].
As Fig. 3 demonstrates, the main NH3 desorption peak centered at 183 oC and only a small hump
o
centered at 565 C were observed in the spectrum of HZSM-5, assigned to the weak and strong
o
acidic sites, respectively. For H, the NH3 desorption peak location is at 189 C with a broad
shoulder peak appearing between 300 oC and 400 oC, demonstrating that both the weak and medium
acidic sites appear simultaneously on this zeolite. For HY, the NH3 desorption peak corresponding
to the weak acidic sites appears at 196 oC, while the medium and strong acidic sites are not obvious.
With medium acidity introduced, the catalytic activity of CHC for Ni/His significantly enhanced
and the promotion effect can be attributed to the synergistic effect between metallic Ni and
Hzeolite [29]. The increased medium acidic sites over Ni/H seem to be generated from acidic
[Ni(OH)+] group [30].
3.3. Mechansim for CHC of BOB

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In the absence of Ni, the reaction predominantly yields 2-BPH (82.0%), 4-BPH (8.9%), and
o
phenol (5.2%) over Hat 160 C and 4MPa H2 for 2 h. The selectivity of other products such as
trimeric compounds and toluene is low. It is proposed that the 2 major products, 2- and 4-BPH, are
obtained by acid-catalyzed Calk-O bond cleavage to produce phenol and benzylium and benzylium
addition to 2- and 4-positions in phenol. The third product, phenol, is obtained via acid-catalyzed
Calk-O bond cleavage. It is impossible for benzylium to abstract H- over H during this process and
the missing benzylium may contribute to the formation of dibenzylphenols. The conversion of BOB
was also performed under N2 atmosphere over Ni10%/Hand the results are shown in Table S2.
2-BPH, 4-BPH, and phenol are also the main products and the product distribution is similar with
the H-catalyzed reaction in all the observed instances, which could further confirm our assumption
that BOB is rearranged to 2- and 4-BPH over the acid sites of Ni10%/H
It was reported that benzyl radicals could attack the naphthalene ring in 1-benzylnaphthalene
hydrocracking [31]. The aromatic rings are rich in electrons and the hydroxyl group makes the
benzene rings more electronic. Moreover, benzyliums are electron deficient and the tendency of
benzyliums to attack aromatic rings is stronger than that of benzyl radicals. Active metals, such as
Fe, Ni, and Pd, proved to be effective for catalyzing the formation of H…H [32,33]. In the present of
an acidic catalyst, H2 can be heterolytically split to an immobile H− adhered to the catalyst surface
and a mobile H+ [34]. Since H…H bond is weaker than H-H bond in H2, heterolytically splitting
H…H bond to produce the mobile H+ is easier. As a result, Ni/ can activate H2 to H…H and
facilitate the heterolytical splitting of H…H to a mobile H+ and immobile H–, as shown in Scheme 1.
Based on the above analyses, the possible mechanism for CHC of BOB under H2 atmosphere
over Ni/H is depicted in Scheme 1. The conversion of BOB over Ni/Hmainly proceeds via

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Calk-O bond cleavage induced by H+ addition to produce phenol and benzylium, benzylium addition
to 2- and 4-positions in phenol to produce 2- and 4-benzylphenols, hydrogenation of the
benzylphenols
to
(cyclohexylmethyl)cyclohexanols,
dehydration
of
(cyclohexylmethyl)cyclohexanols to (cyclohexylmethyl)cyclohexyliums, and abstraction of H- from
Ni/H surface by (cyclohexylmethyl)cyclohexyliums to DCHM. The conversion of BOB over
Ni/H minorly proceeds via Calk-O bond cleavage induced by H+ addition to produce phenol and
benzylium and abstraction of H- from Ni/Hsurface by benzylium to toluene followed by CHC of
the resulting phenol and toluene to produce CH and MCH. The resulting benzyliums from the
Calk-O bond cleavage attack the 2,6- and 2,4-positions of phenol to produce 2,6-dibenzylphenol
(2,6-DBP) and 2,4-dibenzylphenol (2,4-DBP), respectively, followed by the dibenzylphenols
hydrogenation along with subsequent dehydration and H- abstraction to yield
1,3-bis(cyclohexylmethyl)cyclohexane (1,3-BCMC).
3.4. Reusability of Ni10%/H for CHC of BOB
To investigate the reusability of catalyst, the separated Ni10%/H was washed by acetone and
o
dried under vacuum at 50 C for 4 h. Without other treatments, Ni10%/H was used repeatedly for
CHC of BOB at 160 °C, 4 MPa of H2, and 2 h. As Fig. S4 depicts, both the BOB conversion and the
selectivity of BCCs dropped from the initial 100% and 68.3% to 90.1% and 48.6%, respectively,
after the catalyst was reused for 3 recycles. TEM image of the recycled catalyst illustrates that the
main reason for the decrease of catalyst activity is the aggregation of Ni particles on the catalyst
surface (Fig. S5). However, the carbon deposition on the surface of catalyst is also supposed to
influence the activity of Ni/H relatively.
3.5. CHC of BOB with the pretreatment under N2 atmosphere

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Because of the high selectivtiy for intermediate of benzylphenols over Ni/H under N2
atmosphere, a novel approach to producing more BCCs, namely, indirect CHC (ICHC), was
o
presented. ICHC of BOB was carried out over Ni10%/H at 160 C and 4MPa N2 for 10 min. Then,
the products from the first step were subjected to ICHC process over Ni10%/Hat 160 oC and 4MPa
H2 for 2 h, producing DCHM (71.1%), CPEC (11.1%), CH (5.2%), MCH (0.6%), and 1,3-BCMC
(4.6%) (Process I in Table S3). However, a one-step reaction, namely, direct CHC (DCHC), was
o
performed over Ni10%/H at 160 C and 4MPa H2 for 2 h, which produces DCHM (52.6%), CPEC
(15.7%), CH (7.8%), MCH (3.5%), and 1,3-BCMC (4.7%) (Process II in Table S3). BCCs account
for 82.2% and 68.3% in the products from ICHC and DCHC process, respectively. The difference in
selectivity of BCCs can be attributed to the suppression to the abstraction of H- from Ni/Hsurface
by benzylium under N2 atmosphere in ICHC.
4. Conclusions
In conclusion, bifunctional Ni/H exhibits a high activity for CHC of BOB due to the synergistic
effect between metallic Ni and H zeolite. The highest selectivity of BCCs accounting for 68.3% is
obtained in one-step CHC for the first time. The possible mechanism is that H+ attacks BOB to
produce phenol and benzylium and benzylium adds to 2- and 4-positions in phenol to produce
benzylphenols followed by the benzylphenols hydrogenation along with subsequent dehydration
and H- abstraction to yield BCCs over Ni/H. Moreover, the conversion of BOB proceeded under
N2 atmosphere then H2 atmosphere, yielding a much higher selectivity of BCCs. These results
indicate that CHC process with the pretreatment under N2 atmosphere, which can effectively
suppress the abstraction of H- from Ni/Hsurface, might be useful to selectively produce BCCs as
high value jet fuels from lignin.

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Acknowledgements
This work was subsidized by the Key Project of Joint Fund from National Natural Science
Foundation of China and the Government of Xinjiang Uygur Autonomous Region (Grant
U1503293) and the Program of University in Jiangsu Province for Graduate Student’s Innovation in
Science Research (Grant KYLX15_1414).
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Figure captions
Fig. 1. XRD patterns of H zeolite and supported Ni catalysts.
Fig. 2. XPS and fitting curve of Ni 2p3/2 for Ni10%/H.
Fig. 3. NH3-TPD profiles for different acidic zeolites and Ni10%/H.
Scheme 1. Possible pathways for CHC of BOB under H2 atmosphere over Ni10%/H.

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Ni
H
(111)
(200)
(220)
Ni10%/H
H
Ni10%/HY
Ni10%/HZSM-5
Ni10%/AC
6 12 18 24 30 36 42 48 54 70 76 82 88 94
2(o)
Fig. 1. XRD patterns of H zeolite and supported Ni catalysts.

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O 1s
Ni/H
Ni 2p
Si 2p
C 1s
Al 2p
1200 1000 800 600 400 200
0
Ni 2p3/2
measured
fitting
852.4
856.0
861.5
854.4
866
861
856
851
846
Binding energy (eV)
Fig. 2. XPS and fitting curve of Ni 2p3/2 for Ni10%/H.

ACCEPTED MANUSCRIPT
HY
Ni10%/H
H
HZSM-5
100
200
300
400
500
600
Temperature (oC)
Fig. 3. NH3-TPD profiles for different acidic zeolites and Ni10%/H.

ACCEPTED MANUSCRIPT
H-
H
H
H...
H
+ H2
OH
Ni/H
Ni/H
Ni/H
Ni/H
β
H+
β
β
β
+
OH
HOH
H-
+
+ 3 H...
H
+ H+
Ni/H
- H2O
+ H+
+
H
H-
+
H-
+
O
O
+
H

Ni/H
+ 3 H...
H
+

Ni/H
path 1
+
O
OH
pyrolysis
+
+
+
+
H +
+
HOH
O
at 160 o
C
+ 6 H...
H
+
H +
OH
OH
+
- H+
- H2O
OH
H
H
+
O
+
H-
Ni/H
+
OH
+
+
+ H+
path 2
+
- H+
HO
H+
- H2O
+ 6 H...
H
H
+
H
+
+
HO
+
H
- H+
HO
OH
+
HOH
+
H +
+ 9 H...
H
OH
- H2O
OH
+
H-
OH
OH
- H+
+ H+
+

+
Ni/H
H
+
O
O
+
path 3
+ 9 H...
H
+
- H2O
OH
H
+ H+

ACCEPTED MANUSCRIPT
Scheme 1. Possible pathways for CHC of BOB under H2 atmosphere over Ni10%/H.

ACCEPTED MANUSCRIPT
Table 1 CHC of BOB over supported Ni catalysts.
Product selectivity (%)
Conve
rsion
(%)
C
H
L
B
Tri
mer
s
Catalyst
C
H
M
M
Tolu
Phe DC CP
2-B 2-B 4-B
CH PH PH
C
nol HM EC
H
CP CH ene
Ni10%/A
C
1.
6
28.
29.0
3
33
.5
95.5
54.7
100
2.8
Ni10%/H
ZSM-5
Ni10%/H

14
.9
7.
8
26.
34.0
6
7. 16.
9
3
15.
7
0.2 3.5 0.6
0.3 4.3 18.5
0.2 52.6
8.5 3.0 3.2
4.7
3.4
Ni10%/H
Y
8.
2
0. 15.
27.
8
84.9
12.0 0.4 3.6 1.5
4.1
3
0
MCP: methylcyclopentane; CHL: cyclohexanol; BCH: benzylcyclohexane; 2-BCH:
2-benzylcyclohexanol; Trimers: including dibenzylphenols and 1,3-BCMC.

ACCEPTED MANUSCRIPT
Table 2 CHC of BOB over Ni10%/H for different periods of reaction time.
Product selectivity (%)
MCP MCH Toluene Phenol DCHM CPEC BCH
Reaction time Conversion
(min)
(%)
CH
5.9
6.7
7.7
7.7
7.8
2-BC
1.5
10
30
80.0
100
100
100
100
1.7
2.0
2.4
2.8
3.5
3.8
2.6
2.4
1.7
0.6
3.0
1.9
1.5
0.7
0.2
15.4
24.5
31.4
41.5
52.6
1.7
3.2
3.9
6.7
8.7
8.8
8.5
2.7
60
4.7
3.5
90
9.9
3.6
120
0.2
15.7
3.0
H2 atmosphere; MCP: methylcyclopentane; BCH: benzylcyclohexane; 2-BCH:
2-benzylcyclohexanol; Trimers: including dibenzylphenols and 1,3-BCMC.

ACCEPTED MANUSCRIPT
Graphical abstract

ACCEPTED MANUSCRIPT
Highlights
 Ni/Hwas first found to be effective for converting BOB into bicyclic cycloalkanes (BCCs).
 BOB is quickly rearranged to benzylphenols and then further hydrodeoxygenated to BCCs.
 The selectivity of BCCs can be further improved with the pretreatment under N2 atmosphere.