摘要
隨著化石資源日益減少，進而使丙烯、丙烷頓失來源，而糠醛可由生質廢棄物水解而來，在不影響全球糧食供給下，是具有潛力的生質化學原料。在先前研究中發現，高氫氣濃度的糠醛催化反應中，具有大鎳金屬粒徑的Ni/SiO2-C觸媒具較低的糠醛轉化活性，於低溫反應時具有高FOL選擇率而小粒徑的Ni/SiO2觸媒則有較高的呋喃選擇率，且有更進一步的脫羰產物C3產生；因此，本研究以鎳觸媒催化糠醛加氫的氣相反應，以探討反應條件與觸媒特性對於糠醛脫羰反應選擇率之影響。於第一部份研究中，由於產製連續脫羰反應的C3產物，理論糠醛與氫氣進料比為1:1，因此於本研究中探討降低糠醛催化反應中的氫氣濃度，不論鎳金屬粒徑大小，皆可以受到低氫氣濃度影響，於低反應溫度時抑制氫化產物，使C3產物選擇率升高；為討論第二階段的脫羰反應的現象，將中間產物FR當作初始反應物，發現產物選擇率的分布並未受Ni金屬顆粒大小的影響，而氫氣影響較為顯著，降低氫氣濃度的同時，也造成觸媒失活程度較高。
為了改善鎳觸媒易積碳的缺點，本研究擬以兩種策略對觸媒進行改質，鉀參雜的鎳觸媒可擁有良好的穩定性，雖可能因覆蓋部分step site進而使氫化產物選擇率提升，但FR仍有繼續開環脫CO的能力，因此C3產率不減反增。而添加硼普遍認為可防止Nickel carbide的生成，在本研究中NiB/SiO2於高氫氣濃度下的糠醛催化反應，可改善觸媒穩定性，且於高氫氣濃度下即擁有高C3產率，然而於較低氫氣濃度下對觸媒穩定性並沒有顯著的提升，與FR脫羰反應特性一致。

關鍵詞: 糠醛、鎳觸媒、脫羰、C3、鉀、硼

Abstract
Furfural can be obtained from biowaste and can be used as a platform chemical for producing valuable chemicals. The furfural conversion using various metal catalysts indicates that furfural can lead to different useful chemicals economically and competitively. The product distribution can be altered by the type of metal, reaction temperature and hydrogen concentration. Instead of precious metal, the cheap nickel-based catalysts are examined in this study. Our previous study shows that nickel particle size can result in different catalytic activity, product selectivity and C3 can be obtained through sequential decarbonylation of furfural. In this study, we confirm the reaction pathway of sequential decarbonylation to C3 and the effect of hydrogen concentration is examined. The Ni/SiO2 catalysts are inactive without hydrogen while decarbonylation selectivity can be increased significantly with hydrogen concentration decrease. However, the decrease of hydrogen concentration also leads to more serious catalyst deactivation. In order to increase the resistance of coke formation, we have two strategies modifying the Ni catalyst to prevent the coke. Although Ni catalysts with K doping have higher hydrogenation products, Ni/K1-SiO2 shows the higher stability and maintains high C3 selectivity. It might indicate that doping K might block the active site for decarbonylation reaction. Extensive studies regarding doping B in Ni catalyst have been considered. In our case, NiB/SiO2 shows high stability and has high C3 selectivity with high H2 concentration in FFR reaction, but not really promote the stability with lower H2 concentration in FFR reaction.
Keywords:Furfural, decarbonylation, Ni catalyst, potassium, boron, C3

1. de Souza, R.L., et al., 5-Hydroxymethylfurfural (5-HMF) Production from Hexoses: Limits of Heterogeneous Catalysis in Hydrothermal Conditions and Potential of Concentrated Aqueous Organic Acids as Reactive Solvent System. Challenges, 2012. 3(2): p. 212-232.
2. Wang, J., et al., Efficient Catalytic Conversion of Lignocellulosic Biomass into Renewable Liquid Biofuels via Furan Derivatives. RSC Adv., 2014. 4(59): p. 31101-31107.
3. Daniel E. Resasco, S.S., Jimmy Faria, Teerawit Prasomsri and a.M.P. Ruiz, 5. Furfurals as chemical platform for biofuels production. Research Signpost, 2011.
4. Xing, R., et al., Production of jet and diesel fuel range alkanes from waste hemicellulose-derived aqueous solutions. Green Chemistry, 2010. 12(11): p. 1933.
5. Shi, S., H. Guo, and G. Yin, Synthesis of maleic acid from renewable resources: Catalytic oxidation of furfural in liquid media with dioxygen. Catalysis Communications, 2011. 12(8): p. 731-733.
6. Verdeguer, P., N. Merat, and A. Gaset, Lead/platinum on charcoal as catalyst for oxidation of furfural. Effect of main parameters. Applied Catalysis A: General, 1994. 112(1): p. 1-11.
7. Zeitsch, K.J., The Chemistry and technology of furfural and its many by-products, Elsevier Science B.V. Amsterdam. 2000: p. 28-33.
8. Zheng, H.-Y., et al., Towards understanding the reaction pathway in vapour phase hydrogenation of furfural to 2-methylfuran. Journal of Molecular Catalysis A: Chemical, 2006. 246(1–2): p. 18-23.
9. Sitthisa, S. and D.E. Resasco, Hydrodeoxygenation of Furfural Over Supported Metal Catalysts: A Comparative Study of Cu, Pd and Ni. Catalysis Letters, 2011. 141(6): p. 784-791.
10. Xu, C., et al., Effect of activation temperature on the surface copper particles and catalytic properties of Cu–Ni–Mg–Al oxides from hydrotalcite-like precursors. Catalysis Communications, 2011. 12(11): p. 996-999.
11. Hronec, M., K. Fulajtarová, and T. Liptaj, Effect of catalyst and solvent on the furan ring rearrangement to cyclopentanone. Applied Catalysis A: General, 2012. 437–438(0): p. 104-111.
12. Hronec, M. and K. Fulajtarová, Selective transformation of furfural to cyclopentanone. Catalysis Communications, 2012. 24(0): p. 100-104.
13. Yang, Y., et al., Conversion of furfural into cyclopentanone over Ni-Cu bimetallic catalysts. Green Chemistry, 2013. 15(7): p. 1932-1940.
14. Claus, P., Selective hydrogenation of ά,β-unsaturated aldehydes and other C=O and C=C bonds containing compounds. Topics in Catalysis, 1998. 5(1-4): p. 51-62.
15. Li, M., et al., Selective production of furfuryl alcohol via gas phase hydrogenation of furfural over Au/Al2O3. Catalysis Communications, 2015. 69: p. 119-122.
16. Li, H., et al., Liquid phase hydrogenation of furfural to furfuryl alcohol over the Fe-promoted Ni-B amorphous alloy catalysts. Journal of Molecular Catalysis A: Chemical, 2003. 203(1–2): p. 267-275.
17. Liaw, B.-J., et al., Preparation and catalysis of amorphous CoNiB and polymer-stabilized CoNiB catalysts for hydrogenation of unsaturated aldehydes. Applied Catalysis A: General, 2008. 346(1–2): p. 179-188.
18. Kijeński, J., et al., Platinum deposited on monolayer supports in selective hydrogenation of furfural to furfuryl alcohol. Applied Catalysis A: General, 2002. 233(1–2): p. 171-182.
19. Ratna Shekhar, M.A.B., Russell V. Plank and John M. Vohs, Adsorption and Reaction of Aldehydes on Pd Surfaces. J. Phys. Chem. B, 1997. 101: p. 7939-7951.
20. Nakagawa, Y., et al., Total Hydrogenation of Furfural over a Silica-Supported Nickel Catalyst Prepared by the Reduction of a Nickel Nitrate Precursor. ChemCatChem, 2012. 4(11): p. 1791-1797.
21. Yu, W., et al., Theoretical and experimental studies of the adsorption geometry and reaction pathways of furfural over FeNi bimetallic model surfaces and supported catalysts. Journal of Catalysis, 2014. 317: p. 253-262.
22. Sitthisa, S., et al., Kinetics and mechanism of hydrogenation of furfural on Cu/SiO2 catalysts. Journal of Catalysis, 2011. 277(1): p. 1-13.
23. Sitthisa, S., et al., Conversion of furfural and 2-methylpentanal on Pd/SiO2 and Pd–Cu/SiO2 catalysts. Journal of Catalysis, 2011. 280(1): p. 17-27.
24. Pushkarev, V.V., et al., High Structure Sensitivity of Vapor-Phase Furfural Decarbonylation/Hydrogenation Reaction Network as a Function of Size and Shape of Pt Nanoparticles. Nano Letters, 2012. 12(10): p. 5196-5201.
25. Lukes, R.M. and C.L. Wilson, Reactions of Furan Compounds. XI. Side Chain Reactions of Furfural and Furfuryl Alcohol over Nickel-Copper and Iron-Copper Catalysts1. Journal of the American Chemical Society, 1951. 73(10): p. 4790-4794.
26. Wilson, C.L., Reactions of Furan Compounds. X. Catalytic Reduction of Methylfuran to 2-Pentanone. Journal of the American Chemical Society, 1948. 70(4): p. 1313-1315.
27. Sitthisa, S. and D. Resasco, Hydrodeoxygenation of Furfural Over Supported Metal Catalysts: A Comparative Study of Cu, Pd and Ni. Catalysis Letters, 2011. 141(6): p. 784-791.
28. Zhang, H., et al., Atomic Layer Deposition Overcoating: Tuning Catalyst Selectivity for Biomass Conversion. Angewandte Chemie International Edition, 2014. 53(45): p. 12132-12136.
29. Cai, Q.-X., et al., Mechanistic insights into the structure-dependent selectivity of catalytic furfural conversion on platinum catalysts. AIChE Journal, 2015. 61(11): p. 3812-3824.
30. Srivastava, R.D. and A.K. Guha, Kinetics and mechanism of deactivation of Pd/Al2O3 catalyst in the gaseous phase decarbonylation of furfural. Journal of Catalysis, 1985. 91(2): p. 254-262.
31. Xu, W., et al., Direct catalytic conversion of furfural to 1, 5-pentanediol by hydrogenolysis of the furan ring under mild conditions over Pt/Co2 AlO4 catalyst. Chemical Communications, 2011. 47(13): p. 3924-3926.
32. Xu, J. and M. Saeys, First principles study of the coking resistance and the activity of a boron promoted Ni catalyst. Chemical Engineering Science, 2007. 62(18-20): p. 5039-5041.
33. Abild-Pedersen, F., et al., Mechanisms for catalytic carbon nanofiber growth studied byab initiodensity functional theory calculations. Physical Review B, 2006. 73(11).
34. Bengaard, H.S., et al., Steam Reforming and Graphite Formation on Ni Catalysts. Journal of Catalysis, 2002. 209(2): p. 365-384.
35. ROSTRUP-NIELSEN, J.R., Sulfur-Passivated Nickel Catalysts for Carbon-Free Steam Reforming of Methane. JOURNAL OF CATALYSIS 1984. 85: p. 31-43.
36. F. Besenbacher, I.C., B. S. Clausen, B. Hammer, A. M. Molenbroek, J. K. Nørskov and I. Stensgaard, Design of a Surface Alloy Catalyst for
Steam Reforming. SCIENCE, 1998. 279(5358): p. 1913-1915.
37. Meng, F., et al., Effect of promoter Ce on the structure and catalytic performance of Ni/Al2O3 catalyst for CO methanation in slurry-bed reactor. Journal of Natural Gas Science and Engineering, 2015. 23: p. 250-258.
38. Omoregbe, O., et al., Influence of Lanthanide Promoters on Ni/SBA-15 Catalysts for Syngas Production by Methane Dry Reforming. Procedia Engineering, 2016. 148: p. 1388-1395.
39. Yang, X., et al., Characterization and performance evaluation of Ni-based catalysts with Ce promoter for methane and hydrocarbons steam reforming process. Fuel, 2016. 179: p. 353-361.
40. Alipour, Z., M. Rezaei, and F. Meshkani, Effect of alkaline earth promoters (MgO, CaO, and BaO) on the activity and coke formation of Ni catalysts supported on nanocrystalline Al2O3 in dry reforming of methane. Journal of Industrial and Engineering Chemistry, 2014. 20(5): p. 2858-2863.
41. Alipour, Z., M. Rezaei, and F. Meshkani, Effects of support modifiers on the catalytic performance of Ni/Al2O3 catalyst in CO2 reforming of methane. Fuel, 2014. 129: p. 197-203.
42. Xu, J. and M. Saeys, Improving the coking resistance of Ni-based catalysts by promotion with subsurface boron. Journal of Catalysis, 2006. 242(1): p. 217-226.
43. Xu, J., et al., Effect of boron on the stability of Ni catalysts during steam methane reforming. Journal of Catalysis, 2009. 261(2): p. 158-165.
44. Sung-hun Lee, K.Y.K., Un Ho Jung, Yong-Gun Shul, Wang Lai Yoon, Pre-reforming of n-tetradecane over Ni/MgO–Al2O3 catalyst: effect of added potassium on the coke resistance. Research on Chemical Intermediates, 2016. 42: p. 4317-4332.
45. Juan-Juan, J., M.C. Román-Martínez, and M.J. Illán-Gómez, Effect of potassium content in the activity of K-promoted Ni/Al2O3 catalysts for the dry reforming of methane. Applied Catalysis A: General, 2006. 301(1): p. 9-15.
46. Philippe Lejemble, A.G.a.P.K., From Biomass to Furan Through Decarbonylation of Furfural under Mild Conditions. Biomass, 1984. 4(4): p. 263-274.
47. Zhang, W., et al., A study of furfural decarbonylation on K-doped Pd/Al2O3 catalysts. Journal of Molecular Catalysis A: Chemical, 2011. 335(1-2): p. 71-81.
48. Fouskas, A., et al., Boron-modified Ni/Al2O3 catalysts for reduced carbon deposition during dry reforming of methane. Applied Catalysis A: General, 2014. 474: p. 125-134.
49. Huang, H.-H., et al., Application of boron-modified nickel catalysts on the steam reforming of ethanol. International Journal of Hydrogen Energy, 2014. 39(35): p. 20712-20721.
50. Zheng, J., et al., Promoting effect of boron with high loading on Ni-based catalyst for hydrogenation of thiophene-containing ethylbenzene. Catalysis Communications, 2012. 21: p. 18-21.
51. Lin, S.H.C.S.D., The preparartion of Ni Catalysts for Gas-Phase Furfural Conversion with Hydrogen. 2015: National Taiwan University of Science and Technology.
52. Louis, C., Z.X. Cheng, and M. Che, Characterization of nickel/silica catalysts during impregnation and further thermal activation treatment leading to metal particles. The Journal of Physical Chemistry, 1993. 97(21): p. 5703-5712.
53. J.A. Moulijn, A.E.v.D., F. Kapteijn, Catalyst deactivation: is it predictable? What to do? Applied Catalysis A: General, 2001. 212: p. 3-16.
54. Bartholomew, C.H., Carbon Deposition in Steam Reforming and Methanation. Catalysis Reviews, 2007. 24(1): p. 67-112.
55. Shaobin Wang, G.Q.M.L.a.G.J.M., Carbon Dioxide Reforming of Methane To Produce Synthesis Gas over Metal-Supported Catalysts: State of the Art. Energy & Fuels, 1996. 10: p. 896-904.
56. Mireille Richard-Plouet, M.G., Serge Vilminot, Ce´dric Leuvrey, Claude Estourne`s and Mohamedally Kurmoo, hcp and fcc Nickel Nanoparticles Prepared from Organically Functionalized Layered Phyllosilicates of Nickel(II). Chem. Mater., 2007. 19: p. 865-871.
57. Gong, J., et al., Structural and magnetic properties of hcp and fcc Ni nanoparticles. Journal of Alloys and Compounds, 2008. 457(1-2): p. 6-9.
58. Chen, Y., et al., Preparation and magnetic properties of nickel nanoparticles via the thermal decomposition of nickel organometallic precursor in alkylamines. Nanotechnology, 2007. 18(50): p. 505703.
59. Christina Papadopoulou, H.M., Xenophon Verykios, Catalysis: Alternative Energy Generation. Chapter 3: Utilization of biogas as a renewable carbon source: dry reforming of methane. , ed. L.G.A. Erdôhelyi. 2012, New York: Springer Science+Business Media.
60. Chiang, R.-K., 介穩態Hcp Ni的形成與磁特性, 2015, 碩士論文,國立中興大學
61. Chang, T.-H. and F.-C. Leu, Dynamics of bimetallic Ni–Cu catalysts. J. Chem. Soc., Faraday Trans., 1996. 92(12): p. 2291-2296.
62. Cheng, C., et al., Methanation of syngas (H2/CO) over the different Ni-based catalysts. Fuel, 2017. 189: p. 419-427.
63. Meng, F., et al., Catalytic performance of CO methanation over La-promoted Ni/Al2O3 catalyst in a slurry-bed reactor. Chemical Engineering Journal, 2017. 313: p. 1548-1555.
64. Tornoyuki Inui, M.F., and Yoshinobu Takegaml, Simultaneous Methanation of CO and CO, on Supported Ni-Based Composite Catalysts. Industrial & Engineering Chemistry Product Research and Development, 1980. 19: p. 385-388.
65. Michiaki Yamasaki, H.H., Takeshi Yoshida, Eiji Akiyama,, K.A. Asahi Kawashima, Koji Hashimoto,, and K.S. Mitsuru Komori, Compositional dependence of the CO2 methanation activity of Ni/ZrO2 catalysts prepared from amorphous Ni-Zr alloy precursors. Applied Catalysis A: General, 1997. 163: p. 187-197.
66. Zhang, X., W.-j. Sun, and W. Chu, Effect of glow discharge plasma treatment on the performance of Ni/SiO2 catalyst in CO2 methanation. Journal of Fuel Chemistry and Technology, 2013. 41(1): p. 96-101.
67. Hu, X. and G. Lu, Inhibition of methane formation in steam reforming reactions through modification of Ni catalyst and the reactants. Green Chemistry, 2009. 11(5): p. 724.
68. Juan-Juan, J., M.C. Román-Martı́nez, and M.J. Illán-Gómez, Catalytic activity and characterization of Ni/Al2O3 and NiK/Al2O3 catalysts for CO2 methane reforming. Applied Catalysis A: General, 2004. 264(2): p. 169-174.
69. Iwasa, N., T. Yamane, and M. Arai, Influence of alkali metal modification and reaction conditions on the catalytic activity and stability of Ni containing smectite-type material for steam reforming of acetic acid. International Journal of Hydrogen Energy, 2011. 36(10): p. 5904-5911.
70. Osaki, T. and T. Mori, Role of Potassium in Carbon-Free CO2 Reforming of Methane on K-Promoted Ni/Al2O3 Catalysts. Journal of Catalysis, 2001. 204(1): p. 89-97.
71. M. MONTES, C.P.D.B., B.K. HODNETT, F. DELANNAY, P. GRANGE and and B. DELMON, INFLUENCE OF METAL-SUPPORT INTERACTIONS ON THE DISPERSION, DISTRIBUTION,
REDUCIBILITY AND CATALYTIC ACTIVITY OF Ni/SiO2 CATALYSTS. Applied Catalysis,, 1984. 12: p. 309-330.