Preparation and catalytic performance of a novel organometallic CoH/Hβ catalyst for: n -hexane isomerization

Article abstract of DOI:10.1039/d0nj01437k

As a novel alkane isomerization catalyst, namely CoH/Hβ, was prepared by the reduction of CoH(P(OPh)3)4, which was pre-impregnated on Hβ as support. The as-prepared CoH/Hβ catalyst was structurally compared with CoH(P(OPh)3)4, CoH(P(OPh)3)4/Hβ via FT-IR, TPR, SEM, XRD and other techniques. The results show that the new organometallic hydride catalyst was synthesized successfully and exhibited excellent catalytic performance for the isomerization of n-hexane. For the best performance of the CoH/Hβ catalyst, the optimal catalytic reaction temperature, pressure, space velocity, and hydrogen/oil molar ratio were 300 °C, 2.0 MPa, 1.0 h-1, and 4.0, respectively, in the isomerization process of n-hexane. Under the optimal reaction conditions, the conversion of n-hexane, the yield of isomerization, and the selectivity towards iso-paraffins were 80.2%, 63.0%, and 78.6%, respectively. This performance is mainly attributed to the new structure of Co-H hydride in the CoH/Hβ catalyst, which has strong hydrogenation/dehydrogenation activity in the isomerization of n-hexane. This journal is

Full text of DOI:10.1039/d0nj01437k

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Preparation and Catalytic Performance of a Novel Organometallic
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CoH/Hβ catalyst for n-hexane isomerization
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Mei Zhang a, Congcong Wang b, Chao Zhang a, Tingting Cai a, Lijun Zhu a,* and Daohong Xia a,b,
*
a State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580,
China,
b College of Chemical Engineering, Shengli College China University of Petroleum, Dongying 257061, China.
* Corresponding author. E-mail: zhulijun@upc.edu.cn, xiadh@upc.edu.cn.
As a novel alkane isomerization catalyst, CoH/Hβ was prepared by the reduction of CoH(P(OPh)3)4, which was pre-impregnated
on the supporter of Hβ. The prepared CoH/Hβ catalyst was comparatively studied on the structures with CoH(P(OPh)3)4,
CoH(P(OPh)3)4/Hβ by FT-IR, TPR, SEM, XRD and other means. The results show that this new organometallic hydride catalyst
was synthesized successfully and exhibited excellent catalytic performance for isomerization of n-hexane. For the best
performance of CoH/Hβ catalyst, the optimal catalytic reaction temperature, pressure, space velocity, and hydrogen/oil molar
ratio were 300oC, 2.0 MPa, 1.0 h-1, and 4.0 in the isomerization process of n- hexane. Under the optimal reaction conditions, the
conversion of n-hexane, the yield of isomerization, and the selectivity of iso-paraffins were 80.2 %, 63.0 %, and 78.6 %,
respectively. This is mainly attributed to
a new structure of Co-H hydride in CoH/Hβ catalyst, which has strong
hydrogenation/dehydrogenation activity in isomerization of n-hexane.
1. Introduction
Hydro-isomerization of n-alkanes have attracted much research attentions because of their high gasoline octane
numbers and environmentally friendly properties.1-5 Selectively isomerizing n-paraffins into iso-paraffins with
catalysis, which can improve the octane number of a gasoline fraction, has been applied in industry.6-7 For the
isomerization catalysts, the aprotic acids were firstly applied for performing the isomerization of n-paraffins and
it was difficult to meet industrial requirements owing to their low activity.8 Then the noble metal bifunctional
catalysts were systematically developed, which involved isomerization/cracking on acid sites and
hydrogenation/dehydrogenation on metal sites. These industrial isomerization processes operated at high
reaction pressure in general and had common drawbacks of high investment because of the presence of noble
metals.1,9-13
So far, it’s a great motivation to design new catalysts for the catalytic isomerization process. Non-noble metals
such as Ni and Co are becoming new stars.14-18 Jeong et al.14 reported that the activity of Co, Ni, Fe, Mn, and Cu
catalyst was measured in the hydrogenation reaction, and Co-catalyst exhibited a higher hydrogenation rate. Our
previous investigation revealed that the performance of isomerization could be effectively promoted by
introducing Ni-catalyst.19 The non-noble metal catalyst seems to be a promising candidate as substitutes for
traditional noble metals.
Transition metal hydrides have been widely used for various catalytic reactions, especially in the catalytic
homogeneous isomerization of olefins, due to their unique structures, properties, and excellent chemical
reactivity.20-24 However, to our knowledge, there are no reports on the isomerization of n-hexane catalyzed by
cobalt hydrides until now. Herein, a novel bifunctional Co-based transition metal hydride with unique structure
was successfully synthesized and used in the isomerization of n-alkane for the first time. The preparation and
reaction conditions for CoH/Hβ in isomerization of n- hexane were studied to achieve the optimal catalytic
performance and reaction mechanism.
2 Experiment section
2.1. Materials
Triphenyl phosphite (P(OPh)3, CP, ≥99%), cobalt nitrate hexahydrate (Co(NO3)2·6H2O, AR, ≥99%), ethanol
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(C2H5OH, AR, ≥99%), sodium borohydride (NaBH4, AR, 96%), and xylene (C7H8, AR, 99%) were all provided by
Sinopharm Chemical Reagent Co., Ltd. n-Hexane (C6H14, AR, ≥99%) and n-pentane (C5H12, AR, ≥99%) were
purchased from Xilong Chemical Co., Ltd. Hβ molecular sieve was supplied by Tianjin Nanhua Catalyst Co., Ltd.,
with a specific surface area of 690 m2/g, silicon/aluminum atomic ratio of 25, crystallinity of more than 96.3% and
particle size of 1.5 μm.
2.2. Preparation of Catalysts
CoH(P(OPh)3)4 was synthesized according to the reported procedure.25 P(OPh)3 (3.1 g, 0.01 mol) was dissolved in
a solution of Co(NO3)2·6H2O (0.582 g, 0.002 mol) in ethanol (20 mL). NaBH4 (0.2 g, 0.005mol), dissolving in hot
ethanol (10 mL), was dropped into the stirred cobalt nitrate solution, and then it can be observed that the purple
cobalt salt disappeared rapidly with a pale-yellow precipitate appeared. The precipitate was washed by ethanol
and dried overnight at 80 °C in vacuum to give a pale-yellow crude product. The crude product was dissolved in
hot xylene (50 mL), and filtered while hot and re-crystallized by adding ethanol to the filtrate. Then the final
product CoH(P(OPh)3)4 was obtained.
The purchased Hβ was disposed before the preparation of the catalyst precursor CoH(P(OPh)3)4/ Hβ. At first,
Hβ and Al2O3 powder were uniformly mixed according to a certain mass ratio, and then added an appropriate
amount of distilled water, and the composite was squeezed out from TBL-2 type catalyst forming device. The
formed catalyst carrier was firstly baked under an infrared lamp, grinded to a certain particle size, and then
activated in a muffle furnace at 300°C. The pretreated Hβ carrier was equal volume impregnation with a solution
of CoH(P(OPh)3)4 in dichloromethane for 24h, and dried at 80°C under N2 for 2h. The obtained CoH(P(OPh)3)4/Hβ
was further packed in the middle of a reaction tube, and reduced with hydrogen at 300°C for 3h. Finally, the
catalyst CoH/Hβ was prepared.
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2.3. Characterization of Catalysts and Catalytic Testing
The synthesized catalysts were characterized by FT-IR, H2-TPR, NH3-TPD, SEM, XRD and other related means, and
the catalyst performance was evaluated on a 550×8 mm fixed-bed reactor. For details, see supporting
information S1 and S2.
3. Results and discussion
3.1. Characterization
Infrared spectra of P(OPh)3、CoH(P(OPh)3)4、CoH(P(OPh)3)4/Hβ、CoH/Hβ and Hβ were characterized to verify
the existence of an unique structure of Co-H and listed in Fig. S1 and Fig.1a respectively.
As shown in Fig. S1, two adjacent peaks of CoH(P(OPh)3)4 at position of 2360 cm-1 and 2345 cm-1 respectively,
appeared in its spectrum compared with that of P(OPh3)4, which are ascribed to the stretching vibration of Co-P.
26
There was no obvious Co-H band of CoH(P(OPh)3)4 could be observed in Fig. S1, because the vibration of Co-H
bond very weak.27 Fig. 1a shows that when CoH(P(OPh)3)4 was loaded on disposed Hβ, its two characteristic
peaks still existed in the spectrum while signal associated with the hydroxyl group of Hβ at band of 3421 cm-1
doesn’t emerge. Upon treatment of CoH(P(OPh)3)4/Hβ with hydrogen reduction at 300°C, the typical peaks of the
obtained CoH/Hβ was similar with that of Hβ, demonstrating that the Co-P coordination bond disappeared, and
novel catalyst CoH/Hβ equipped Co-H structure was obtained.
Fig.1
FT-IR spectra of CoH(P(OPh)3)4/Hβ, CoH/Hβ and Hβ (a) and XRD patterns of CoH(P(OPh)3)4, the disposed
Hβ and catalyst CoH/Hβ (b)
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Fig. 1b lists the crystalline phase of CoH/Hβ, the disposed Hβ and the precursor CoH(P(OPh)3)4. TheDdOifIf:r1a0c.t1i0o3Vn9ie/wDA0rNticJl0e1O4n3li7nKe
peaks of CoH(P(OPh)3)4 are sharp and intense, indicating its highly crystallinity nature.28 Interestingly, no obvious
characteristic peaks assigned to CoH were detected after reduction, which implies the well-dispersion of CoH on
Hβ.
Fig. 2a and 2b show the SEM images of CoH/Hβ at different scales and the element Co mapping was shown in
Fig. 2c. It can be seen clearly from Fig. 2a and 2b that irregular spherical CoH nanoparticles were well dispersed
on the surface of carrier, and the distribution of Co on Hβ was uniform in Fig. 2c, which was consistent with the
XRD results.
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Fig. 2 SEM images of CoH/Hβ at different scales (a) 1μm, (b) 500 nm, and (c) Co mapping of CoH/Hβ.
Fig. 3a exhibits the H2 TPR curve of CoH(P(OPh)3)4. There exists one reduction peak at 235°C and another two
adjacent negative peaks at 260°C and 300°C, respectively, indicating CoH(P(OPh)3)4 could be reduced at a
temperature below 250°C. The appearance of other two negative peaks, which is assumed to the disconnection
of Co-H bond and the release of H2 from CoH. The NH3-TPD Profiles of the disposed Hβ, CoH(P(OPh)3)4/Hβ and
CoH/Hβ are presented in Figure 3b. The profiles of all samples show that there are two desorption peaks in the
range of 100-600°C and they are observed around 170°C and 390°C. The signal intensity of NH3-TPD profiles of
CoH/Hβ catalysts was stronger than that of CoH(P(OPh)3)4/Hβ and Hβ, indicating that more weak and strong acid
sites exist on CoH/Hβ catalysts, especially the weak acid sites. The effect of carriers on n-hexane isomerization
was shown in Fig. S4. As can be seen from Fig. S4, the conversion and yield of isomerization on Hβ were higher
than that of other two carriers.
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Fig. 3 H2 TPR curve of CoH(P(OPh)3)4 (a) and NH3-TPD profiles of CoH/Hβ, CoH(P(OPh3)4)/Hβ and the disposed
Hβ (b).
Nitrogen adsorption isotherms were operated to verify the porous structure of catalyst CoH/Hβ and the
disposed carrier Hβ, which are shown in Fig. 4. Both samples present the same isotherm types and have
absorption at a relative pressure less than 0.2, which are characteristic of microporous materials.29 With relative
pressure ranges from 0.42 to 1.0, a significant absorption increase appears in Fig. 4, which means that the
mesoporous structure may be formed by the accumulation of CoH particles over zeolite surface.30 The mesopore
sizes of CoH/Hβ and the disposed Hβ are concentrated between 2.5 nm and 7.5 nm, and pore size distribution
(inset) is summarized in Fig. 4.
CoH/Hβ
Hβ
0
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Pore diameter/nm
CoH/Hβ
Hβ
0.0
0.2
0.4
0.6
0.8
1.0
Relative pressure(p/p0)
Fig. 4 Nitrogen adsorption isotherms of CoH/Hβ and the disposed Hβ.
The pores structural characteristics of CoH/Hβ and the disposed Hβ based on nitrogen adsorption are
encapsulated in Table 1.
Table 1 Textural description of CoH/Hβ and the disposed Hβ.
c
Samples
SBETa/m2·g-1
Vmpb/cm3·g-1
VT / cm3·g-1
CoH/Hβ
511.42
0.14
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Disposed carrier Hβ
559.10
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DOI: 10.1039/D0NJ01437K
a Specific surface area. SBET was calculated by BET method.
b Micropore volume. Vmp was calculated by t-plot method.
c Total pore volume of samples.
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Comparing with that of the disposed carrier Hβ, the BET surface area of catalyst CoH/Hβ decreased from
559.10 m2/g-1 to 511.42 m2/g-1, and micropore volume reduced from 0.16 cm3/g-1 to 0.14 cm3/g-1, indicating that
the loading of active components only change the pore structure to a certain extent.
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3.2. Effect of Preparation Conditions on the Catalytic Performance of CoH/Hβ
The preparation conditions, such as the activation temperature of catalyst, the loading of metal, and the particle
size of carrier may have effects on the catalytic activity of the bi-functional catalyst CoH/Hβ. In fact, the
optimization of the preparation conditions, such as calcination temperature and heating rate, has been
31-32
researched extensively.
shown in Fig. 5.
The influence of preparation conditions of CoH/Hβ on its catalytic behavior are
Fig. 5 Effect of preparation conditions of CoH/Hβ on n-hexane isomerization ( (a) activation
temperature(activation time,4h; particle size, 0.2mm; Co loading in catalyst,0.5%), (b) activation time(activation
temperature,500°C; particle size, 0.2mm; Co loading in catalyst,0.5%), (c) catalyst particle size(activation
temperature,500°C; activation time,4h; Co loading in catalyst,0.5%) and (d) Co loading in catalyst (activation
temperature,500°C; activation time,4h; particle size, 0.2mm;). )
Fig. 5a illustrates the effect of activation temperature on the catalytic behavior of CoH/Hβ catalyst. The
conversion and yield of isomerization both rise first when activation temperature was below 500°C, and then
reach the maximum conversion rate (71.7%) and the maximum yield of isomer (57.6%) at 500°C. Then the
conversion and yield of isomerization decrease with further increasing activation temperature, which was
probably contributed to the destruction of the surface structure of CoH/Hβ at high activation temperature.
Fig. 5b displays the influence of activation time on catalytic behavior of CoH/Hβ catalyst. With the increase of
activation time, the conversion of n-hexane, the selectivity of iso-paraffins, and the productivity of iso-paraffins
rises flatly and then keeps in steady, respectively. A suitable activation time of CoH/Hβ catalyst is 2 h.
The catalytic performance of CoH/Hβ for n-hexane isomerization was found to be less dependent on particle
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sizes of catalyst, as shown in Fig. 5c But it still showed a slight increase in isomerization when particle size of
catalyst was 0.2 mm. Catalyst with small particle size has large surface area. However, catalyst with tDoOoI:sm10a.1l0le3r9/D0NJ01437K
particle size results in dense catalyst bed, which leads to the pressure drop rise inside the reaction tube and the
pipeline can potentially become blocked.
Fig. 5d exhibits the effect of Co loading in CoH/Hβ on the isomerization of n-hexane, showing the optimal
catalytic activity was at 0.5wt.% of Co loading. iso-Hexane production decreased when Co loading on Hβ was
more than 0.5wt.%, which demonstrated that excessive Co loading may cause CoH particles to assemble over
supporter surface and weak the catalytic performance of CoH/Hβ catalyst.
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3.3. Effect of Reaction Conditions on the Catalytic Performance of CoH/Hβ
The effects of different reaction conditions, such as reaction temperatures, pressures, hydrogen/oil molar ratios
and mass space velocities, were investigated in order to obtain optimum catalytic performance of CoH/Hβ
catalyst.
Fig. 6a shows the catalytic ability of CoH/Hβ at different reaction temperatures for isomerization of n-hexane.
As reaction temperature increases, the conversion of n-paraffin gradually increases, the selectivity of isomer
declines. The yield of iso-hexane firstly elevates and then declines, and shows a maximum at 300°C. High
temperature is benefit for the reaction kinetics of isomerization, but excessive heat leads to the side reaction like
cracking. Therefore, 300°C seems to be a satisfactory reaction temperature to obtain high yield and selectivity for
the entire isomerization reaction.
Fig. 6b displays the catalytic ability of CoH/Hβ at different reaction pressures. As the reaction pressure
increases from 1.0 MPa to 2.0 MPa, the yield and selectivity was increased, while the conversion was decreased.
It was inferred, therefore, that an increasing in H2 pressure promoted the hydrogenation of olefin intermediates
generated during the isomerization process and inhibited the coking reaction of isomerization feeds. As H2
pressure further increased from 2.0 MPa to 4.0 MPa, the yield of iso-hexane decreased, which was thought of
high H2 pressure preventing the dehydrogenation of n-hexane to olefins that was important to the isomerization
process. Thinking about the feed conversion and the isomer yield, the H2 pressure was optimized at 2.0 MPa.
The hydrogen oil molar ratio reflects the partial pressure of n-hexane in the gas phase of the reaction system.
It’s obviously in Fig. 6c that hydrogen to oil ratio with 4 is suitable. The lower ratio of hydrogen to oil is beneficial
to the dehydrogenation of n-hexane to hexenes, which leads to high concentration of active olefins in the system
and more isomerization reaction inducing. Conversely, high ratio of hydrogen to oil over normal range reduces
the concentration of n-hexane in the gas phase and prevents the production of olefins.
Fig. 6d shows the influence of space velocities on catalytic behavior of CoH/Hβ. The conversion of n-hexane
reached 80.2% at the space velocity 1.0 h-1, while it decreased to 75% at 2 h-1. The change of yield of iso-hexane
was similar, ranging from 63% at 1.0 h-1 to 44 % at 2.5 h-1. These results could be explained by the fact that great
space velocity shorted the residence time of n-hexane feedstock on the catalyst bed, leading to the inhibition of
the isomerization of n-hexane. Therefore, mass space velocity 1.0 h-1 was more suitable.
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Fig. 6 Effect of reaction conditions on n-hexane isomerization catalyzed by CoH/Hβ. ( (a) reaction
temperature (reaction pressure, 2.0MPa; WHSV, 1.0h-1; Hydrogen oil molar ratio, 4.0), (b) reaction pressure
(reaction temperature, 300°C; WHSV, 1.0h-1; Hydrogen oil molar ratio, 4.0), (c) hydrogen to oil molar ratio
(reaction temperature, 300°C; reaction pressure, 2.0MPa; WHSV, 1.0h-1), (d) mass airspeed (reaction pressure,
300°C; reaction pressure, 2.0MPa; Hydrogen oil molar ratio, 4.0).)
3.4. Catalyst catalyzed isomerization of n-pentane and C5/C6 mixed feedstock.
In order to further evaluate the catalytic performance of CoH/Hβ, the isomerization of n-pentane and C5/C6
mixed feedstock catalyzed by CoH/Hβ were carried out respectively. Fig. S2 displays the effect of reaction
temperature on n-pentane isomerization. The result is similar with that of the isomerization of n-hexane, which
implies that temperature of 300°C is an optimum temperature for the isomerization reaction. The composition of
C5/C6 mixed feedstock influences the isomerization rate of light alkanes and the octane number of the obtained
products, as shown in Table 2. Isomerization rates of alkanes and RON of products indicate the difference of
depth of isomerization.
Table 2. The result of C5/C6 mixed feedstock isomerization
Composition of C5/C6 mixed
C5 isomerization rate /%
C6 isomerization rate /%
RON
feedstock（Vn-C5/Vn-C6
）
3:1
1:1
1:3
38.9
47.5
41.7
51.2
50.1
42.5
70.3
59.8
60.2
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The C6 isomerization rates are always higher than that of the C5 feed in Table 2, which reveals n-hexane is
easily isomerized than n-pentane. The reduction of RON of products becomes pronounced as the n-hexane
increase in the C5/C6 mixed feedstock.
3.5 Reaction mechanism
The mechanism for alkane isomerization catalyzed by traditional bifunctional catalysts is no longer a hot topic.
However, the unique structure of cobalt hydride in the novel catalyst CoH/Hβ may bring interesting information
on the isomerization of n-paraffin. Firstly, the need for hydrogen was examined in the alkane isomerization with
hydrogen and nitrogen atmosphere respectively.33
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Fig. 7a shows that the catalytic performance of CoH/Hβ in H2 was better than that of in N2, which
demonstrated hydrogen atmosphere was in favor of the isomerization. On the other hand, the catalytic
performance of CoH/Hβ before and after H2 pre-reduction is almost same in Fig. 7b, indicating this novel catalyst
doesn’t require any H2 pre-reduction operation, which provides a great advantage compared to traditional
bifunctional catalyst. The study on the catalysts used in Fig. 7 has a definite assistance in proposing catalytic
mechanisms. Therefore, XRD patterns of CoH/Hβ before and after H2 pre-reduction have been provided to study
the change of the crystallinity and crystal phase in Fig. S3. It illustrated that characteristic peak intensity is of the
same before and after H2 pre-reduction. Meanwhile, the peak intensity significantly decreased after the catalyst
used in N2. After further analyzing the SEM image and element Co mapping in SEM in Fig. 8a and 8b, the surface
morphology of CoH/Hβ did not change after H2 reduction, and the distribution status of Co on Hβ exhibits similar
uniformity compared with catalyst before H2 reduction in Fig. 2c. On the contrary, it emerged that carbon
deposition covered on the catalyst surface of CoH/Hβ after it was used in N2 and the amount of Co element
decreased clearly, this conclusion is in good agreement with the previous XRD analysis in Fig. S3.
In addition, TEM images with particle size charts of CoH/Hβ were also studied in Fig. 8c and 8d. It can be seen
from Fig.8c that the CoH particles was uniformly dispersed on the carrier, with the average particle size around
1.3ꢀnm. While after the catalyst worked in N2 (Fig.8d), the corresponding average particle sizes is closed to 9.3
nm, indicating obviously amorphous carbon covered on the catalyst surface and leading to reduce the catalytic
performance. It turns out that isomerization reaction involves hydrogenation and dehydrogenation on the metal
center of catalyst CoH/Hβ, and the coking rate is delayed in H2 atmosphere to maintain the activity of acid center.
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Fig. 7 The effect of N2 and H2 on n-hexane isomerization (a), The effect of H2 pre-reduction on the catalyst
activity of CoH/Hβ (b), The effect of isopentene (c), tert-butanol (d), and chloro-n-butane (e) on n-hexane
isomerization (reaction temperature, 300°C; reaction pressure, 2.0 MPa; WHSV, 1.0 h-1; Hydrogen oil molar ratio,
4.0).
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Fig.8 SEM images and SEM mappings of CoH/Hβ (a) H2 pre-reduction for 2 h and (b) after worked in N2, TEM
images with particle size charts of CoH/Hβ (c) before and (d) after worked in N2.
The influence of several kinds of carbonium ions initiators (iso-pentene, tert-butanol, and chloro-n-butane) on
catalytic behavior of CoH/Hβ catalyst were then studied and the results are listed in Fig. 7c, 7d and 7e. In terms of
these carbonium ions initiators, there was no obvious effect on catalytic isomerization, which demonstrated
CoH/Hβ catalyst itself having the function of catalytic producing carbonium ions. Therefore, alkane could be
catalyzed to form olefin intermediate on metal sites of CoH/Hβ, and then the intermediate converted to
carbonium ions on acid sites of CoH/Hβ, exhibiting synergetic properties in catalytic isomerization process 34-35
.
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Scheme 1 Mechanism of isomerization of n-hexane on CoH/Hβ
The reaction mechanism36-37 includes four steps all together is proposed in scheme 1, which involves
formation of n-hexene by dehydrogenation on CoH active center (Step 1), formation of n-C6 carbonium ions over
acid sites of zeolite (Step 2), transfer of n-C6 carbonium ions into i-C6 carbonium ions and formation i-C6 hexene
by deprotonation (Step 3), and finally hydrogenation of i-C6 hexene to i-C6 hexane over CoH/Hβ catalyst surface
( Step 4). The good catalytic performance of CoH/Hβ was assumed to be the Co-H bond in the cobalt hydride that
could be beneficial to hydrogenation and dehydrogenation in the isomerization process. The CoH metal sites
worked together with the acid sites and synergically catalyzed the n-hexane isomerization.
4. Conclusion
In summary, the catalyst CoH/Hβ has been prepared successfully in this work through impregnation reduction
method, which has not been reported up to now. The preparation and reaction conditions all have great
influences on catalytic performance of the catalyst. Optimum catalysts activity and selectivity in the isomerization
of n-hexane has been achieved at 300°C with a Co loading of 0.5 wt.%, in which the conversion of n-hexane, the
selectivity of iso-paraffin and the yield of isomerization are 80.2%, 78.6% and 63.0%, respectively. The
mechanism of isomerization of n-hexane on CoH/Hβ was investigated, which revealed that the synergetic
catalytic action by acid and metal sites plays a key role in the performance of CoH/Hβ. The application of metal
hydride loaded on zeolite will bring us some inspiration on the catalytic isomerization of light alkanes.
Acknowledgments
This work was financially supported by the National Natural Science Foundation of China (Grant U1662115) and
Shandong Province Natural Science Foundation (ZR2019MB057).
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Preparation and Catalytic Performance of a Novel Organometallic CoH/Hβ catalyst
for n-hexane isomerization
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novel organometallic catalyst CoH/Hβ was synthesized and directly provide
hydrogenation/dehydrogenation effects in isomerization of n-hexane
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