Research progress in catalysts for producing higher alcohols from bioethanol
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摘要: 与乙醇相比,高级醇具有高的十六烷值、高能量密度、对发动机部件无腐蚀性、与水不混溶、稳定性好等直接作为燃料或燃料添加剂的优势,将发酵产生的生物乙醇转化为更有价值的高级醇受到了广泛关注。本文综述了近年来国内外有关生物乙醇制高级醇的研究进展,包括金属氧化物、羟基磷灰石(HAP)和负载型金属催化剂的研究开发现状,并比较了不同类型催化剂参与下乙醇转化率和高级醇选择性,结合乙醇经缩合反应制备高级醇的机理进行了讨论,最后对当前生物乙醇制高级醇的挑战以及未来研究趋势进行了总结与展望,指出多功能催化剂的开发是未来研究重点,羟醛缩合是进一步提高生物乙醇制高级醇转化率与选择性的有效策略。Abstract: Compared with ethanol, higher alcohols have the advantages of high Cetane number, high energy density, non corrosiveness to engine parts, immiscibility with water, good stability, and other advantages as fuel or fuel additive directly. The conversion of fermentation bioethanol into more valuable higher alcohols has attracted widespread attention. This paper reviewed the research progress of bioethanol to higher alcohols at home and abroad in recent years, including the research and development of metal oxides, hydroxyapatite (HAP) and supported metal catalysts, Finally, the current challenges and future research trends of bioethanol to higher alcohols are summarized and prospected, pointing out that the development of multifunctional catalysts is the focus of future research, and Aldol condensation is an effective strategy to further improve the conversion and selectivity of bioethanol to higher alcohols.
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Key words:
- bioethanol /
- higher alcohol /
- catalysts /
- reaction mechanism
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图 1 乙醇的转化途径[11]
Figure 1 Conversion pathway of ethanol (with permission from Nat. Rev. Chem. Publications)
图 2 木质纤维素生物质发酵制生物乙醇[14]
Figure 2 Fermentation of Lignocellulose Biomass to Produce Bioethanol (with permission from Industrial Ind Crops Prod Publications)
图 3 采用CO2/NH3-TPD对催化剂的酸碱度进行表征[21]
Figure 3 Characterization of the acidity and alkalinity of the catalyst using CO2/NH3-TPD (a) MA: MgAlOx catalysts; (b) CMA: CuMgAlOx catalysts (with permission from J. Fuel Chem. Technol. Publications)
图 4 Co0.15Mg2.85AlOx催化剂的催化性能[23]
Figure 4 Catalytic performance of Co0.15Mg2.85AlOx catalyst (with permission from Green Chem. Publications)
图 5 OM-CuxLayAl100催化剂的反应路径和机理[24]
Figure 5 Reaction Path and Mechanism of OM-CuxLayAl100 Catalyst (with permission from Appl. Surf. Sci. Publications)
图 6 Cu-HAP催化剂的催化性能和反应路径[29]
Figure 6 Catalytic performance and reaction pathway of Cu HAP catalyst (with permission from ACS Catal Publications)
图 7 (A)多孔BAP-Ni上的反应途径; (B)无孔BAP-Ni催化剂[30]
Figure 7 Reaction pathway on (A) porous BAP-Ni; (B) nonporous BAP-Ni catalyst (with permission from ACS Sustain. Chem. Eng. Publications)
图 8 (A)8h后的产物选择性:负载量分别为2.5g/L(白色)和10g/L(紫色)HAP, 2.5g/L(黄色), 10g/L(棕色); (B)8h后的产物分布:Cu/MgAl (蓝色); Ru/MgAl (黄色); Pd/MgAl (绿色); Pt/MgAl (灰色)[38]
Figure 8 (A)Product selectivity after 8 hours: loading amounts of 2.5g/L (white) and 10g/L (purple) HAP, 2.5g/L (yellow), and 10g/L (brown), respectively; (B)Product distribution after 8 hours: Cu/MgAl (blue); Ru/MgAl (yellow); Pd/MgAl (green); Pt/MgAl (gray) (with permission from Green Chem. Publications)
图 9 催化剂的制备工艺示意图和SEM图像[50]
Figure 9 Schematic diagram of catalyst preparation process and SEM diagram(a)NiSn@C-5/1-500, (b)NiSn@C-1/2-500, (c)NiSn@C-1/5-500, (d)NiSn@C-1/2-300, (e)NiSn@C-1/2-600, (f)NiSn@C-1/2-800 (with permission from Energy Convers. Manag Publications)
图 10 Ni20Sn1@NC催化剂的催化性能[51]
Figure 10 Ni20Sn1@NC Catalytic performance of catalysts (with permission from Ind. Eng. Chem. Res. Publications)
图 11 催化剂制备示意图和表征分析[52]
Figure 11 Schematic diagram and characterization analysis of catalyst preparation (with permission from ACS Catal Publications)
图 12 乙醇在Ni和Sn-Ni上解离的结构图以及偶联机制[53]
Figure 12 Structure diagram and coupling mechanism of ethanol dissociation on Ni and Sn-Ni (with permission from Appl. Catal. B Publications)
图 13 电荷密度分布以及Bader电荷转移[54]
Figure 13 Charge density distribution and Bader charge transfer (with permission from Chem. Eng. J Publications)
图 14 不同碳化温度下的XRD图以及演化示意图[55]
Figure 14 XRD patterns and evolution diagrams at different carbonization temperatures (with permission from Fuel Publications)
表 1 金属氧化物催化剂
Table 1 Metal oxide catalysts
Catalysts Reaction conditions Conv.(%) Sel.(%) Reference MgO 450 ℃,0.5 g catalyst,N2 10 ml/min,7 h 56.1 32.7 15 MgO 400 ℃,0.2 g catalyst,6% ethanol,1.3atm 23.0 34.0 16 Mg-ZrO2 400 ℃ 52.0 35.0 17 Mg-Al(Mg/Al=3) 350 ℃,0.3 g catalyst,12% ethanol,
atmospheric pressure,12 h35.0 40.0 18 Cu1MgAl3O 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h2.5 43.0 20 Cu5MgAl3O 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h4.1 40.0 20 Cu10MgAl3O 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h4.5 28.0 20 Cu20MgAl3O 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h3.8 18.0 20 Pd5MgAlO 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h3.8 72.7 20 Ag5MgAlO 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h1.6 38.8 20 Mn5MgAlO 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h0.7 53.3 20 Fe5MgAlO 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h0.3 39.2 20 Sm5MgAlO 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h1.3 66.3 20 Yb5MgAlO 200 ℃,0.5 g catalyst,39.5 g ethanol,
autogenic pressure,5 h1.2 53.0 20 CuMgAlOx 260 ℃,0.1 MPa,GHSV=750 mL·gcat−1·h−1,
LHSV=2 mL·gcat−1·h−143.9 48.0 21 CuMgAlOx 350 ℃,0.15 g catalyst,5 h 79.6 32.0 22 Co0.15Mg2.85AlOx 250 ℃,0.1 MPa,0.2 g catalyst,WHSV=0.96 h−1 32.9 95.4 23 OM-Cu4La2.6Al100 260 ℃,3 MPa (N2),LHSV=2 ml/(h·gcat),12 h 52.2 72.2 24 Conv-conversion of ethanol; Sel-selectivity of higher alcohol 表 2 羟基磷灰石(HAP)催化剂
Table 2 Hydroxyapatite (HAP) catalyst
Catalysts Reaction conditions Conv.(%) Sel.(%) Reference HAP Ca/P=1.64 320 ℃,0.21 g catalyst,GHSV=10000 h−1 22.7 62.4 26 HAP (Ca + Sr)/P=1.67 400 ℃,flow=50 mL·min−1,
GHSV=5000 mL·gcat−1·h−1,4 h13.0 76.4 27 Ca-HAP-1(1.59) 400 ℃,atmospheric pressure, GHSV=10000 h−1 16.2 22.2 28 Ca-HAP-2(1.62) 400 ℃,atmospheric pressure, GHSV=10000 h−1 20.8 50.4 28 Ca-HAP-3(1.65) 400 ℃,atmospheric pressure, GHSV=10000 h−1 21.2 62.4 28 Ca-HAP-4(1.67) 400 ℃,atmospheric pressure, GHSV=10000 h−1 15.8 56.2 28 Sr-HAP-1(1.58) 300 ℃,atmospheric pressure, W/Fethanol=130 h·g·mol−1 1.1 69.0 28 Sr-HAP-2(1.64) 300 ℃,atmospheric pressure, W/Fethanol=130 h·g·mol−1 5.9 78.1 28 Sr-HAP-3(1.67) 300 ℃,atmospheric pressure, W/Fethanol=130 h·g·mol−1 7.9 81.7 28 Sr-HAP-4(1.70) 300 ℃,atmospheric pressure, W/Fethanol=130 h·g·mol−1 11.3 86.4 28 Cu-HAP 250 ℃,0.1 g catalyst,
H2 or N2 30 mL·min−1,0.5 h36.6 86.7 29 Ni-HAP 400 ℃,0.25 g catalyst,0.5 mL ethanol, 0.1 MPa N2,24 h 55.6 67.7 30 Conv-conversion of ethanol; Sel-selectivity of higher alcohol 表 3 单金属负载催化剂
Table 3 Monometal Supported Catalysts
Catalysts Reaction conditions Conv.(%) Sel.(%) Reference 5%Ru/Al2O3 300 ℃,0.01−0.05 g catalyst,1.2 g ethanol, autogenic pressure,3 h 12.0 9.0 34 5%Rh/Al2O3 300 ℃,0.01−0.05 g catalyst,1.2 g ethanol, autogenic pressure,3 h 5.0 35.0 34 5%Pd/Al2O3 300 ℃,0.01−0.05 g catalyst,1.2 g ethanol, autogenic pressure,3 h 9.0 21.0 34 5%Pt/Al2O3 300 ℃,0.01−0.05 g catalyst,1.2 g ethanol, autogenic pressure,3 h 3.0 37.0 34 0.8%Au/Al2O3 300 ℃,0.01−0.05 g catalyst,1.2 g ethanol, autogenic pressure,3 h 6.0 35.0 34 6%Ag/Al2O3 300 ℃,0.01−0.05 g catalyst,1.2 g ethanol, autogenic pressure,3 h 2.0 20.0 34 Ag/Mg-Al 250 ℃ 53.7 13.8 35 Ni/γ-Al2O3 230 ℃,WHSV=1.42 h−1,100bar,10 h 41.0 47.5 36 Ni/γ-Al2O3 240 ℃,2 g catalyst,70bar, LHSV=0.1 h−1,10 h 14.0 69.0 37 Cu/γ-Al2O3 240 ℃,2 g catalyst,70bar, LHSV=0.1 h−1,10 h 14.0 64.0 37 Cu/CeO2 260 ℃,1 mL·min−1CO2 and 0.05 mL·min−1EtOH,LHSV=1.97 h−1 39.0 35.0 38 Ru/MgO 400 ℃ 43.0 9.0 39 Au/mTiO2 250 ℃ 74.0 10.0 40 Co/MgAlO 350 ℃ 55.0 33.0 41 Cu/MgAl 230 ℃,0.5 or 2 g catalyst,200 mL ethanol, 30bar N2,8 h --- 81.9 42 Ru/Mg3Al1-LDO 350 ℃,0.5 g catalyst,P(N2)=0.1 MPa, WHSV=3.2 h−1 29.6 82.6 43 Ni@C 0.5 g catalyst,5 MPa H2 initial pressure, 10 h 61.7 85.7 44 Conv-conversion of ethanol; Sel-selectivity of higher alcohol 表 4 多金属负载催化剂
Table 4 Multimetal Supported Catalysts
Catalysts Reaction conditions Conv.(%) Sel.(%) Reference Cu-CeO2/AC 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 39.1 55.2 45 5Cu1Ce/AC 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 46.2 61.8 45 4Cu1Ce/AC 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 45.6 62.7 45 3Cu1Ce/AC 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 46.2 60.0 45 2Cu1Ce/AC 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 46.3 58.7 45 1Cu1Ce/AC 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 44.0 45.5 45 3Cu1Ce/SiO2 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 23.3 12.3 45 3Cu1Ce/A2O3 250 ℃,1.0 g catalyst, 2 MPa(N2), LHSV=4 ml/(h·gcat) 46.9 17.4 45 Ni-Cu/HT 310 ℃, Ni:Cu = 1:1 62.4 34.8 46 Ni/La2O3/Al2O3 230 ℃,30 g catalyst,
reactor pressure=100bar41.0 74.0 47 Ni/Cu/La2O3/β-Al2O3 230 ℃,30 g catalyst,WHSV=2.06h−1 15% 78% 48 NiSn/MgAlO 250 ℃,1g NaOH,10 g H2O,10 g ethanol, 12 h 66.9 93.8 49 NiSn@C 250 ℃,0.5 g catalyst,EtOH/H2O=1,24 h 47.0 36.0 50 NiSn@NC 250 ℃,0.5 g catalyst,15g ethanol,
15 g H2O,1 g NaOH,24 h68.5 31.8 51 NiZn@NC 250 ℃,0.5 g catalyst,15g ethanol,
15 g H2O, 1 g NaOH,24 h75.2 --- 52 Sn-Ni/CS 230 ℃,0.3 g catalysts,0.87 g NaOH,
10 g EtOH,10 g H2O,12 h60.0 85.0 53 NiMo@C 240 ℃,0.6g catalyst,13.5 g C2H5OH,
1.5 g fusel,15.0 g H2O,0.9 g NaOH,12 h89.4 44.7 54 NiSn@C-MgO 250 ℃,0.5 g catalyst,10 g ethanol,
10 g H2O,0.5 g NaOH,12 h73.3 60.9 55 Cu-La2O3/Al2O3 250 ℃, 1.0 g catalyst,3 MPa(N2), LHSV=2 mL·gcat−1·h−1 56.7 76.1 9 Conv-conversion of ethanol; Sel-selectivity of higher alcohol -
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