Catalytic In-Situ Hydrogenation of Furfural over Bimetallic Cu-Ni Alloy

Subscriber access provided by Kaohsiung Medical University

Kinetics, Catalysis, and Reaction Engineering

Catalytic In-Situ Hydrogenation of Furfural over Bimetallic Cu-Ni Alloy Catalysts in Isopropanol Zihao Zhang, Zehua Pei, Hao Chen, Kequan Chen, Zhaoyin Hou, Xiuyang Lu, Pingkai Ouyang, and Jie Fu Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.8b00366 • Publication Date (Web): 06 Mar 2018 Downloaded from http://pubs.acs.org on March 7, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

Catalytic In-Situ Hydrogenation of Furfural over Bimetallic Cu-Ni Alloy Catalysts in Isopropanol Zihao Zhanga, Zehua Peia, Hao Chena, Kequan Chenb, Zhaoyin Houc, Xiuyang Lua, Pingkai Ouyanga,b, Jie Fua* a

Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of

Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China b

State Key Laboratory of Materials-Oriented Chemical Engineering, College of

Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China c

Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department

of Chemistry, Zhejiang University, Hangzhou, 310028, China

* Corresponding author Jie Fu, Tel: +86 571 87951065, E-mail address: [email protected]

Abstract: In this work, Al2O3-supported Cu, Ni monometallic and Cu-Ni bimetallic catalysts were synthesized using a co-precipitation method and studied for the in situ hydrogenation of furfural (FAL) with isopropanol as the solvent and hydrogen donor. The Cu-Ni bimetallic catalysts showed improved activity towards the production of 2-methylfuran (2-MF) and

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

2-methyltetrahydrofuran (2-MTHF) over that of monometallic catalysts. The results indicated that isopropanol exhibited better performance than methanol for the in situ hydrogenation of FAL to produce 2-MF and 2-MTHF under the same conditions. The reaction conditions, such as the copper-nickel ratios, catalyst loading amount, reaction temperature and time were optimized. After the reaction was complete, the supported Cu-Ni bimetallic catalyst could be reused four times without a significant loss in catalytic activity. Keywords: Furfural; Isopropanol; In situ hydrogenation; 2-Methylfuran; Copper-nickel alloy.

1. Introduction Due to the fossil resource crisis and growing environmental issues, the catalytic conversion of sustainable biomass resources to fuels and high added-value chemicals has attracted much attention.1, 2 A representative example is the conversion of hemicellulose into molecules such as 2-MF and 2-MTHF, furfuryl alcohol (FOL) and tetrahydrofurfuryl alcohol (THFA) via the platform molecule FAL.3 FAL has been the primarily produced chemical from the lignocellulosic biomass, with an annual production of approximately 280,000 Tm, and is the only commercial building block from lignocellulose owing to its high versatility for the preparation of a wide range of chemicals.4, 5 2-MF and 2-MTHF are good liquid fuel additives with relatively high energy densities, boiling points, and octane numbers and can be partially blended into gasoline for engines. In addition, these additives


Page 2 of 26

Page 3 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


have numerous applications as solvents in organic and, polymer chemistry as well as chemical intermediates for drugs.3 In the presence of molecular H2, the hydrodeoxygenation of FAL has been accomplished over many noble metal and bimetallic based catalysts.6-10 Although the technical feasibility of this upgrading strategy, the use of molecular hydrogen still presents several issues, such as H2 storage, safety, and transportation.11 On this basis, a selective method by catalytic transfer hydrogenation (CTH), employing alcohols and organic acids as the hydrogen donor, has recently gained increased attention. Although the CTH of FAL has been studied over various catalyst, this process is still under development. Vlachos et al. reported a 95% FAL conversion and 61% yield of 2-MF over Ru/C with isopropyl alcohol as the hydrogen donor after 10 h of reaction at 180 °C during the conversion of FAL.12 Then, their group reported the CTH of FAL over a bifunctional Ru/RuOX/C catalyst with 2-butyl alcohol as the hydrogen source with a high 2-MF yield of 76%.13, 14 Wang et al. used an 8 wt% Ru/NiFe2O4 catalyst for the CTH of FAL in the presence of 2-propanol. The conversion of FAL exceeded 97%, and the 2-MF yield reached 83%.15 Zhang et al. reported the CTH of FAL with methanol as the hydrogen donor using inexpensive Cu-based catalysts derived from hydrotalcite precursors, achieving a high 2-MF yield.16 Owing to the many similar properties of 2-MF and 2-MTHF, Chang et al. reported the mixed production of 2-MF and 2-MTHF at 180 °C in the presence of



2-propanol over bimetallic Cu-Pd catalysts, and a total yield of up to 83.9% for 2-MF and 2-MTHF was achieved.3 Although bimetallic Cu-Pd catalysts have been utilized for the in situ hydrogenation of FAL, non-precious bimetallic catalysts have not been investigated. Considering the catalyst cost, more efficient and low-cost systems for the CTH of FAL are still highly desired. Herein, we investigate the use of Al2O3-supported Cu, Ni monometallic and Cu-Ni bimetallic catalysts with different Cu/Ni mass ratios for the CTH of FAL to 2-MF and 2-MTHF. For monometallic Cu/Al2O3, furfuryl ether (FE), as the main by-product, affected the production of the target product, which can be seen in Scheme 1. For Ni/Al2O3, a ring-opening reaction and the production of THFA were mainly responsible for the low yield of 2-MF and 2-MTHF in Scheme 1. Therefore, bimetallic Cu-Ni/Al2O3 catalysts were prepared for the in situ hydrogenation of FAL, and the side reactions were suppressed to the maximum extent. Thereafter, the reaction conditions such as the copper-nickel ratios, catalyst loading amount, reaction temperature and time were optimized. In addition, the reuse performance of the Cu-Ni bimetallic catalyst was examined.


Page 4 of 26

Page 5 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


2. Experimental Section 2.1 Materials

FAL (99%), 2-MF (99%), 2-MTHF (98%) and FOL (99%) were obtained from Aladdin Chemicals (Shanghai, China). Sodium carbonate anhydrous (analytic reagent grade), sodium hydroxide (analytic reagent grade), Cu(NO3)2•3H2O (analytic reagent grade), anhydrous isopropyl alcohol and methanol (analytic reagent grade) were purchased from Sinopharm Chemical Reagent Co. Ltd, China. Ni(NO3)2•6H2O (99.9%) was purchased from STREM Chemical. Al(NO3)3•9H2O (99%) was purchased from Aladdin Industrial Corporation China. Deionized water was prepared in the laboratory. All chemicals were used directly without purification.

2.2 Catalyst synthesis

All catalysts were synthesized using a co-precipitation method according to our previous work.17 Typically, the certain amounts of Cu(NO3)2•3H2O, Ni(NO3)2•6H2O and Al(NO3)3•9H2O were added together in 400 mL deionized water, forming a transparent solution A. Solution B referred to the mixture of 0.8 mol/L NaOH and 0.25 mol/L Na2CO3 respectively. Then, solutions A and B were added dropwise into a three-neck flask with magnetic stirring at 30 °C until a pH value of 9.5 was attained. After aging the precipitate for 7 h at 30 °C, it was separated by filtration and washed thoroughly using deionized water



until the pH was approximately 7. The precipitate was further dried at 110 °C for 12 h and then calcined at 600 °C for 4 h. Before the reaction and testing, these catalysts were activated with H2 at 650 °C for 1 h in a tube furnace, and then cooled under a N2 flow. The total theoretical metal loading of the as-prepared catalysts was 60 wt%.

2.3 Experimental procedures

The catalytic conversion of FAL was carried out in a 14 mL microbatch reactor composed of stainless steel. In a typical experiment, the FAL, catalyst, and hydrogen donor (methanol or isopropyl alcohol) were loaded into the reactor. The sealed reactor was placed in a furnace, which has been heated to the desired reaction temperature. The reactor was removed after the end of the reaction and quickly placed into cool water to quench the reaction. The sample was collected from the cooled reactor and then rinsed with methanol in a 25 mL volumetric flask. Finally, the products were filtered by a 0.45 µm oil membrane and then analyzed.

2.4 Analysis method

The analysis of 2-MF was performed using high-performance liquid chromatography (HPLC, Agilent 1100) equipped with a UV detector. A Phenomenex Gemini C18 column was used, and a 0.6 mL/min water/acetonitrile mixture (60:40, v/v) was chosen as the mobile phase. The temperature of the column was maintained at 30 °C, and the wavelength


Page 6 of 26

Page 7 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


of the UV detector was chosen as 210 nm. The analysis of other liquid substances in methanol was proceeded by gas chromatography (GC, Agilent 7890A) equipped with a flame ionization detector (FID) and a HP-5 capillary column. Nitrogen was chosen as the carrier gas with the injector and detector temperature of 280 °C and 300 °C respectively. Quantitative of products was analyzed by standard curves of each compound. Identification of products was analyzed on a gas chromatography-mass spectrometry (Agilent 5977A MSD) equipment, as well as standard retention times of known compounds. The FAL conversions were calculated as the moles of FAL of consumption divided by the number of moles of FAL before reaction. The selectivities were defined by moles of the products divided by the moles of FAL that reacted. The uncertainties here represented the standard deviations calculated by three replicate experiments. FAL conversion=(MFAL-1-MFAL-2)/ MFAL-1×100% Yield of product=Mproduct/ MFAL-1×100% Here, MFAL-1 is the number of moles of FAL added in the reactor; Mproduct and MFAL-2 refer to the moles of the products and FAL after the reaction, respectively.

2.5 Characterization techniques XRD patterns of the fresh17 and spent catalyst were performed on a PANalytical Empyrean 200895 using 40 kV Ni-filtered Cu Kα radiation (λ=0.154 nm) at 30 mA. The



catalysts were scanned with a 2θ range from 10 to 80°. Scherrer Equation, L=K*λ/(β*cosθ), was used to calculate the crystallite size (L) by XRD results. K is a dimensionless shape factor. λ is the X-ray wavelength. β is the line broadening at half the maximum intensity. θ is the Bragg angle in degrees.

3. Results and discussion 3.1 Initial catalyst screening

Characterization results of 60 wt% Cu/Al2O3 (CuAl), 40 wt% Cu-20 wt% Ni/Al2O3 (Cu2NiAl), 30 wt% Cu-30 wt% Ni/Al2O3 (CuNiAl), 20 wt% Cu-40 wt% Ni/Al2O3 (CuNi2Al) and 60 wt% Ni/Al2O3 (NiAl) revealed the structure that Cu-Ni alloy particles with different Cu/Ni ratios are dispersed on the Al2O3 in different bimetallic Cu-Ni catalysts.17 Furfural contains both C=O and C=C bonds, and the reaction networks of the hydrogenation/hydrogenolysis of furfural are shown in Scheme 1. The process from FAL to 2-MTHF requires the hydrogenation and deoxygenation of aldehyde group in furan ring (– CH=O) and the hydrogenation of C=C double bonds in the furan ring from Scheme 1.18 For clarifying the reaction pathway over different catalysts, the catalytic in situ hydrogenation of FAL over CuAl, Cu2NiAl, CuNiAl, CuNi2Al and NiAl was carried out with 0.1 g of FAL, 0.025 g of the catalyst and 0.7 mL of isopropanol at 210 °C for 4 h in Fig. 1.


Page 8 of 26

Page 9 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Although, the conversions of FAL are 100% over all catalysts, the product distribution was completely different. For example, the yields of 2-MF, 2-MTHF and FOL are 42.4%, 15.2% and 24.3%, respectively over CuAl. However, the main product is 35.5% of THFA over NiAl with 24.4% of 2-MF and 16.6% of 2-MTHF achieved simultaneously. With an increase in the Ni/Cu ratios, the yield of 2-MF increased first from 42.4% over CuAl to 65% over CuNi2Al, and then decreased to 24.4% over NiAl. As shown in Scheme 1, compared with monometallic CuAl and NiAl, CuNi2Al exhibited the highest selectivity towards 2-MF and 2-MTHF under the same reaction conditions. The reasons for this result are as follows: 1) FE was produced by the etherification of FOL over CuAl, Cu2NiAl, CuNiAl and CuNi2Al. Furthermore, the selectivity to FE over CuAl was the highest; 2) The ring-opening reaction and the main by-product, THFA, were achieved over NiAl. Therefore, as shown in Scheme 1, the etherification of FOL leads to a relatively low total yield of 2-MF and 2-MTHF at 57.6% over CuAl. Meanwhile, the ring-opening reaction and the production of THFA was the main reason for the low total yield of 2-MF and 2-MTHF at 41% over NiAl. However, a 73.4% yield of 2-MF and 2-MTHF was obtained over bimetallic CuNi2Al, in which 2-MF was the major product with a 65% yield. These results indicated that the proper combination of Cu and Ni in the bimetallic catalysts to forming a CuNi2 alloy was an appropriate method for the CTH of FAL to produce 2-MF and 2-MTHF. The results of pore textural properties17 showed CuNi2Al with the biggest surface area and



pore volume showed highest catalytic activity. Therefore, a bigger surface area and pore volume might favor of the CTH of furfural. We have also added the performance of Cu-Ni bimetallic catalyst for the CTH of furfural and the comparison with previous published works, which is shown in Table 1.

3.2 Effect of a hydrogen donor

The effect of methanol and isopropanol as the hydrogen donor on the CTH of FAL was evaluated over CuNi2Al with 0.1 g of FAL, 0.025 g of the catalyst and 0.7 mL of the hydrogen donor at 210 °C for 4 h, as shown in Fig. 2. When isopropanol was chosen as the hydrogen donor, 100% conversion of FAL was achieved. In addition, the yields of FOL, 2-MF and 2-MTHF were 21%, 65% and 7.7%, respectively. However, when methanol was chosen as the hydrogen donor, the conversion of FAL decreased to 76.3% under the same reaction conditions. Furthermore, only a 7.2% yield of 2-MF and a 31.8% yield of FOL were obtained. These results indicated that isopropanol performed better than methanol for the CTH of furfural over CuNi2Al. The reason is that the reduction potential of methanol is much higher than isopropanol, which results in a relatively poor performance of methanol as the H-donor.19

3.3 Effect of catalyst loading

Fig. 3 exhibits the conversion of FAL and the yield of 2-MF, 2-MTHF, FOL and


Page 10 of 26

Page 11 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


THFA over CuNi2Al with different catalyst loadings. The experiments were conducted at 230 °C for 4 h in 7 mL of isopropanol with a reactant loading of 0.1 g and catalyst loading ranging from 0.005 g to 0.1 g, meaning that the substrate/catalyst (S/C) ratio ranged from 20:1 to 1:1. The conversion of FAL increased from 79.8% to 100% as the S/C decreased from 20:1 to 8:1, and then was stable with a further decrease in S/C. These results suggest that an S/C of 8:1 is sufficient for the complete conversion of 0.1 g FAL. However, the intermediate FOL was not converted completely with an S/C of 8:1. The yield of FOL decreased from 37.3% to 0 with a decrease in the S/C from 20:1 to 4:1 and then remained steady, but the yield of THFA increased from 4.9% to 29.7% with a further decrease in the S/C from 4:1 to 1:1. Therefore, the S/C of 4:1 was the most suitable for the production of 2-MF and 2-MTHF from the CTH of FAL, because a higher S/C cannot guarantee the complete conversion of all intermediates, and a lower S/C facilitates the occurrence of side reactions to produce THFA.

3.4 In situ hydrogenation of FAL at different temperatures

Fig. 4 shows the conversion of FAL and the yields of 2-MF, 2-MTHF, FOL and THFA over CuNi2Al at different temperatures with a reactant loading and catalyst loading of 0.1 g and 0.025 g respectively. As shown in Fig. 4, the conversion of FAL went up with a prolonged reaction time at different reaction temperatures, and increased continuously with



increasing reaction temperatures from 190 °C to 250 °C. At 190 °C, the conversion of FAL increased rapidly from 43.3% (0.5 h) to 99.4% (4 h) at the beginning and then slightly increased to 100% (6 h). Moreover, the yield of FOL increased first from 0.5 h to 2 h, and then decreased with an increase in the 2-MF yield. However, the yield of 2-MF was still low even after 9 h at a temperature of 190 °C. At 210 °C, 100% conversion of FAL was attained at 4 h, and the FOL intermediates were reacted completely at 9 h. However, the reaction time was too long for the full conversion of the intermediate FOL. For a further reduction in the reaction time, the conversion of FAL at the temperatures of 230 °C and 250 °C was performed, as shown in Fig. 4c and 4d. At 230 °C, the complete conversion of FAL occurred at 2 h, and FOL was also converted fully at 4 h. With a further increase in the reaction time, the 2-MF yield decreased with an increase in the 2-MTHF yield. The yield of the by-product THFA was maintained at a relatively low level (approximately 4%) at different reaction times. As the reaction temperature increased to 250 °C, the conversion rate of FAL continued to increase, but additional side reactions occurred, leading to a decrease in the mass balance of products from 87.4% (at 230 °C for 4 h) to 55.9% (at 250 °C for 4 h). Therefore, the optimal reaction conditions to produce 2-MF and 2-MTHF were 230 °C and 4 h. Under these reaction conditions, a 64.8% yield of 2-MF and a 17.7% yield of 2-MTHF (82.5% yield in total) were achieved with only a 4.9% yield of THFA as the by-product. However, if 2-MTHF was selected as the only target product, then the yield


Page 12 of 26

Page 13 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


of 2-MTHF could also reach 51.2% at 250 °C for 9 h.

3.5 Catalytic maintenance

Catalyst stability is of great importance in practical industrial applications. Therefore, the catalytic maintenance was also evaluated at 230 °C (reaction time=4 h, FAL: 0.1 g, fresh/used catalyst: 0.025 g, isopropanol: 7 mL), as shown in Fig. 5. After the reaction, the catalyst was filtrated, washed with acetone, and dried for the next run. The conversion of FAL over a fresh catalyst (1st use), a catalyst used once previously (2nd use), a catalyst used twice previously (3rd use) and a catalyst used three times previously (4th use) was maintained at 100% as the recycle time increased. The yield of 2-MF slightly decreased from 64.8% to 60.1% in the 4th run. However, the yield of 2-MTHF decreased sharply from 17.7% to 2.4% in the 4th run. To investigate this change, fresh and spent CuNi2Al were analyzed by XRD, as shown in Fig. 6. A strong diffraction peaks at 44.5, 51.8 and 76.4° was discovered between metallic nickel phase (JCPDS #04-0850) and metallic copper phase (JCPDS #65-9743), which belongs to the diffraction peaks of Cu-Ni alloy. The XRD pattern showed that the diffraction peak position and sharpness of the catalyst did not change after use. However, the used catalyst showed a slight increase from 14.6 nm to 16.2 nm in the crystallite size of Cu-Ni alloy, obtained using the Scherrer equation according to 2θ between 43° to 45°. This increase might be responsible for the decrease in the yield of 2-MTHF.



4. Conclusions In summary, the performance of CuNi2Al was better than that of CuAl and NiAl regarding the yields of 2-MF and 2-MTHF. Compared with CuAl and NiAl, the etherification and ring-opening reactions are more difficult over CuNi2Al. FE, as the main by-product, was produced over monometallic Cu/Al2O3, and the ring-opening reaction tended to occur over Ni/Al2O3. Under optimal conditions, a 64.8% yield of 2-MF and a 17.7% yield of 2-MTHF (82.5% yield in total) were achieved at a temperature of 230 °C for 4 h. In addition, if 2-MTHF was selected as the target product, then the yield of 2-MTHF could reach 51.2% at 250 °C for 9 h.

Acknowledgments This work was supported by the National Natural Science Foundation of China (No. 21436007, 21676243, 21706228), the Zhejiang Provincial Natural Science Foundation of China (No. LR17B060002), and the Fundamental Research Funds for the Central Universities.

References (1) Serrano-Ruiz, J. C.; Luque, R.; Sepulveda-Escribano, A. Transformations of biomass-derived platform molecules: from high added-value chemicals to fuels via


Page 14 of 26

Page 15 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


aqueous-phase processing. Chem. Soc. Rev. 2011, 40, 5266-5281. (2) Alonso, D. M.; Wettstein, S. G.; Dumesic, J. A. Bimetallic catalysts for upgrading of biomass to fuels and chemicals. Chem. Soc. Rev. 2012, 41, 8075-8098. (3) Chang, X.; Liu, A. F.; Cai, B.; Luo, J. Y.; Pan, H.; Huang, Y. B. Catalytic transfer hydrogenation of furfural to 2-methylfuran and 2-methyltetrahydrofuran over bimetallic copper-palladium catalysts. ChemSusChem 2016, 9, 3330-3337. (4) Karinen, R.; Vilonen, K.; Niemela, M. Biorefining: heterogeneously catalyzed reactions of carbohydrates for the production of furfural and hydroxymethylfurfural. ChemSusChem 2011, 4, 1002-1016. (5) Jiménez-Gómez, C. P.; Cecilia, J. A.; Durán-Martín, D.; Moreno-Tost, R.; Santamaría-González, J.; Mérida-Robles, J.; Mariscal, R.; Maireles-Torres, P. Gas-phase hydrogenation of furfural to furfuryl alcohol over Cu/ZnO catalysts. J. Catal. 2016, 336, 107-115. (6) Sitthisa, S.; Resasco, D. E. Hydrodeoxygenation of furfural over supported metal catalysts: a comparative study of Cu, Pd and Ni. Catal. Lett. 2011, 141, 784-791. (7) Sitthisa, S.; Sooknoi, T.; Ma, Y.; Balbuena, P. B.; Resasco, D. E. Kinetics and mechanism of hydrogenation of furfural on Cu/SiO2 catalysts. J. Catal. 2011, 277, 1-13. (8) Sitthisa, S.; Pham, T.; Prasomsri, T.; Sooknoi, T.; Mallinson, R. G.; Resasco, D. E. Conversion of furfural and 2-methylpentanal on Pd/SiO2 and Pd-Cu/SiO2 catalysts. J. Catal.



2011, 280, 17-27. (9) Zheng, H. Y.; Zhu, Y. L.; Teng, B.T.; Bai, Z.Q.; Zhang, C.H.; Xiang, H. W.; Li, Y.W. Towards understanding the reaction pathway in vapour phase hydrogenation of furfural to 2-methylfuran. J.Mol. Catal. A-Chem. 2006, 246, 18-23. (10) Lessard, J.; Morin, J. F.; Wehrung, J. F.; Magnin, D.; Chornet, E. High yield conversion of residual pentoses into furfural via zeolite catalysis and catalytic hydrogenation of furfural to 2-methylfuran. Top. Catal. 2010, 53, 1231-1234. (11) Scholz, D.; Aellig, C.; Hermans, I. Catalytic transfer hydrogenation/hydrogenolysis for reductive upgrading of furfural and 5-(hydroxymethyl) furfural. ChemSusChem 2014, 7, 268-275. (12) Panagiotopoulou, P.; Vlachos, D. G. Liquid phase catalytic transfer hydrogenation of furfural over a Ru/C catalyst. Appl. Catal. A-Gen. 2014, 480, 17-24. (13) Gilkey, M. J.; Panagiotopoulou, P.; Mironenko, A. V.; Jenness, G. R.; Vlachos, D. G.; Xu, B. Mechanistic insights into metal Lewis acid-mediated catalytic transfer hydrogenation of furfural to 2-Methylfuran. ACS Catal. 2015, 5, 3988-3994. (14) Panagiotopoulou, P.; Martin, N.; Vlachos, D. G. Effect of hydrogen donor on liquid phase catalytic transfer hydrogenation of furfural over a Ru/RuO2/C catalyst. J.Mol. Catal. A-Chem. 2014, 392, 223-228. (15) Wang, B.; Li, C.; He, B.; Qi, J.; Liang, C. Highly stable and selective Ru/NiFe2O4


Page 16 of 26

Page 17 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


catalysts for transfer hydrogenation of biomass-derived furfural to 2-methylfuran. J. Energy Chem. 2017, 26, 799-807. (16) Zhang, J.; Chen, J. Selective transfer hydrogenation of biomass-based furfural and 5-hydroxymethylfurfural over hydrotalcite-derived copper catalysts using methanol as a hydrogen donor. ACS Sustain. Chem. Eng. 2017, 5, 5982-5993. (17) Zhang, Z.; Yang, Q.; Chen, H.; Chen, K.; Lu, X.; Ouyang, P. K.; Fu, J.; Chen, J. G. In situ hydrogenation and decarboxylation of oleic acid into heptadecane over a Cu-Ni alloy catalyst using methanol as a hydrogen carrier. Green Chem. 2018, 20, 197-205. (18) Dong, F.; Zhu, Y.; Ding, G.; Cui, J.; Li, X.; Li, Y. One-step conversion of furfural into 2-methyltetrahydrofuran under mild conditions. ChemSusChem 2015, 8, 1534-1537. (19) Tang, X.; Chen, H.; Hu, L.; Hao, W.; Sun, Y.; Zeng, X.; Lin, L.; Liu, S.; Conversion of biomass to γ-valerolactone by catalytic transfer hydrogenation of ethyl levulinate over metal hydroxides. Appl. Catal. B-Environ. 2014, 147, 827-834.



Scheme 1. Reaction network of the hydrogenation/hydrogenolysis of FA over CuAl, NiAl and CuNi2Al. The arrows represent the main reaction pathway over the different catalysts.


Page 18 of 26

Page 19 of 26

100 Conversion or selectivities (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


2-MF 2-MTHF FOL THFA

80

FAL conversion 2-MF+2-MTHF

60 40 20 0

CuAl

Cu2NiAl

CuNiAl

CuNi2Al

NiAl

Fig. 1. Conversion of FAL and the yields of 2-MF, 2-MTHF, FOL and THFA over various monometallic and bimetallic catalysts. Reaction conditions: T=210 °C, time=4 h, FAL loading=0.1 g, catalyst loading=0.025 g, and isopropanol=7 mL.



100

Conversion or selectivies (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

80

FAL 2-MF 2-MTHF FOL THFA

60

40

20

0 Methanol

Isopropanol

Fig. 2. Conversion of FAL and the yields of 2-MF, 2-MTHF, FOL and THFA over CuNi2Al with methanol or isopropanol as the hydrogen donor. Reaction conditions: T=210 °C, time=4 h, FAL loading=0.1 g, catalyst loading=0.025 g, and hydrogen donor=7 mL.


Page 20 of 26

Page 21 of 26

80

100 80 60

40 40

Conversion (%)

2-MF 2-MTHF FOL THFA

60

Yieds (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


20 20 0

0 20:1

10:1

8:1

6:1

4:1

2:1

1:1

S/C

Fig. 3. Conversion of FAL and the yields of 2-MF, 2-MTHF, FOL and THFA over CuNi2Al with different catalyst loadings. Reaction conditions: T=230 °C, time=4 h, FAL loading=0.1 g, isopropanol=7 mL, and S/C: the mass ratio of FAL and the catalyst.



100 FAL 2-MF 2-MTHF FOL THFA

80 60 40 20


80

Conversion or yield (%)


100

60 40 20 0

0 0

2

4

6

0

8

2

4

6

8

t/h

t/h

a)

b) 100 FAL 2-MF 2-MTHF FOL THFA

80 60 40 20


100

Coversion or yield (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 26


80 60 40 20 0

0 0

2

4

6

8

0

2

t/h

4

6

8

t/h

c)

d)

Fig. 4. Conversion of FAL and the yields of 2-MF, 2-MTHF, FOL and THFA over CuNi2Al at different reaction temperatures. a) 190 °C; b) 210 °C; c) 230 °C; and d) 250 °C; Reaction conditions: time=4 h, FAL loading=0.1 g, isopropanol=7 mL, and S/C: 4:1.


Page 23 of 26

100

Coversion or selectivies (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



80 60 40 20 0 1st

2nd

3rd

4th

Fig. 5. Recycling of the CuNi2Al catalyst. Reaction conditions: T=230 °C, time=4 h, FAL loading=0.1 g, isopropanol=7 mL, and S/C: 4:1.



Spent Fresh Intensity (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

10

20

30

40

50

60

2θ

Fig. 6. XRD patterns of fresh and spent CuNi2Al catalysts.


70

Page 24 of 26

Page 25 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table 1. The performance of Cu-Ni bimetallic catalyst for the CTH of furfural and the comparison with previous published works Catalyst

Hydrogen donor

Reaction conditions

Conversion

Yield of 2-MF &

/%

2-MTHF/%

Ref.

Cu-Ni

Isopropanol

230 °C, 4 h

100

82.5

Ru/C

Isopropanol

180 °C, 10 h

95

61

12

Ru/RuOx/C

2-Butyl alcohol

180 °C, 10 h

100

75

13,14

Ru/NiFe2O4

Isopropanol

180 °C, 6 h

97

83

15

Cu-Pd

Isopropanol

220 °C, 4 h

100

83.9

3



Catalytic In-Situ Hydrogenation of Furfural over Bimetallic Cu-Ni Alloy Catalysts in Isopropanol Zihao Zhanga, Zehua Peia, Hao Chena, Kequan Chenb, Zhaoyin Houc, Xiuyang Lua, Pingkai Ouyanga,b, Jie Fua*


Page 26 of 26

Catalytic In-Situ Hydrogenation of Furfural over Bimetallic Cu-Ni Alloy

Recommend Documents