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银、钯催化的电化学选择性氢化脱氯反应,浙江工业大学/化学工程学院
绿色化学合成技术国家重点实验室培育基地,徐 颖 华、马红星、丁旭芬、马淳安,Silver, Palladium-electrocatalyzed selective hydrodechlorination,1,目录,1. 银、钯催化的电化学选择性氢化脱氯反应简介,2. 多氯吡啶甲酸的电化学选择性氢化脱氯反应,3. 其他多氯有机物的电化学选择性氢化脱氯反应,4. 总结和展望,Zhejiang University of Technology,2,1.银、钯催化的电化学选择性氢化脱氯反应简介,有机合成：合成部分氯代有机物作为药物中间体或原料药；
要求:区域选择性脱氯。,1.1. 主要用途及要求,Zhejiang University of Technology,Rondinini S., et al. Electroreduction of Halogenated Organic Compounds, 2010, 279;
Alonao F., et al. Chem. Rev., 2002, 102(11): 4009-4091.,环境保护：降解环境中存在的高毒、难降解氯代有机物；
要求：化学选择性脱氯。,,3,,1.2.催化原理,Isse A.A., et al. J. Phys. Chem. C, 2009, 113: 14983;
Wang A., et al. J. Am. Chem. Soc.: 2010, 132: 9534.,,,,,,,Dabo P., et al. Environ. Sci. Technol., 2000, 34: 1265;
Chen G.,et al. J. Phys. Chem. B, 2006, 110: 4863.,Fig. 1.1 The hydrodechlorination mechanism
on silver electrode,Fig. 1.2 The hydrodechlorination mechanism
on palladium electrode,4,2.多氯吡啶甲酸的电化学选择性氢化脱氯,,化工学报, 2010, 61: 699.,Zhejiang University of Technology,5,,,Fig. 2.1 CVs of 3,5,6-T (a) at four electrodes in a N2-saturated 0.25 M PBS at pH = 3, (b) at a Ag(r) electrode in a N2-saturated 0.5 M H2SO4 (pH = 0.2), a 0.5 M NaOH (pH = 13.3) aqueous solution, and 0.25 M PBS of three different pH values (3, 7, and 11); scan rate v = 50 mV s-1, T = 297 K.,Electrochim. Acta, 2015, 151: 284;
ZL 201410264884.1,Zhejiang University of Technology,2.1. 银催化,pH = 3,Ag(r),6,,,Table 2.1 Electrochemical reduction of 3.33 mM 3,5,6-T in a N2-saturated 0.5 M H2SO4 (pH = 0.2), a 0.5 M NaOH (pH = 13.3) aqueous solution, and 0.25 M PBS of three different pH values (3, 7, and 11) at 297 K on five cathodes.,a 2 F·mol-1 of 3,5,6-T were consumed in the all 10 electrolysis experiments.
b Current efficiency calculated with respect to the produced 3,5-D.
c 3,5-D and 3,6-D selectivity calculated with respect to the converted 3,5,6-T.,Zhejiang University of Technology,7,,,Fig. 2.2 Product selectivity and carbon mass balance during the electrochemical reduction of 42.5 mM 3,5,6-T at 297 K. Catholye: 30 mL 0.25 M PBS at pH = 3. Cathode: Ag(r) mesh electrodes (2.5 cm×3 cm).,Zhejiang University of Technology,8,,Zhejiang University of Technology,,Fig. 2.3 Effects of pH on the selectivity for hydrodechlorination of TeCP on silver cathodes.,,9,Fig. 2.5 LSV of Ni foam, Ag mesh, Cu foam electrodes, and Pd/Ni foam, Pd/Ag mesh, Pd/Cu foam electrodes in a 0.5 M NaOH aqueous solution, v = 5 mV/s, with two concentrations of 3,6-D, Temperature: 25 ℃.,Fig. 2.4 SEM of Ni and Pd/Ni foam, Ag and Pd/Ag mesh, Cu and Pd/Cu foam.,ZL 201510401434.7;
ZL 201510401039.9.,Zhejiang University of Technology,2.2. 钯催化,Pd/Ni foam,Ni foam,Ag mesh,Cu foam,Pd/Ag mesh,Pd/Cu foam,10,Table 2.2 Effect of electrolyte composition on the ECH dechlorination of 0.25 M 3,6-D.a,a Cathode: a Pd/Ni foam (Projected area: 2×6 cm2, Pd loading: 2.25 mg/cm2).
c CE was calculated with △t = 6 h.
d 3,6-D was added into the catholyte in a divided fashion during the first hour of electrolysis due to its poor solubility.,Zhejiang University of Technology,11,,Fig. 2.6 Effect of pH on product selectivity and CE during the ECH dechlorination of 3,6-D. Cathode: a Pd/Ni foam; Catholyte: (A and A’) 50 mL 1.25 M NaOH + 96 mM 3,6-D, and B’ (B ) 50 mL 0.75 M H2SO4 + 96 mM 3,6-D+ 20% v/v Ethanol; CE was calculated with △t = 1, 2, 3, 4, 5 or 6.0 h.,Zhejiang University of Technology,12,Scheme 1 Proposed mechanisms for the ECH dechlorination of 3,6-D.,Zhejiang University of Technology,13,,Fig. 2.7 Effects of cathode catalysts and pH on the selectivity for hydrodechlorination of TeCP.,Zhejiang University of Technology,,,14,3.其他多氯有机物电化学选择性氢化脱氯,,3.1.三氯甲基苯,Fig. 3.1 CV of 5.0 mM benzenyltrichloride and benzyl chloride, in CH3CN + 0.1 mM TBAP on Ag electrode (ø 2 mm), at 298K, v = 100 mV s-1, T = 20 ℃.,物理化学学报, 2013, 29: 973.,Zhejiang University of Technology,Ag electrode,Ag electrode,15,,Table 3.1 Electroreduction of benzenyltrichloride at Ag mesh (2.5×3.0 cm2), in 40 mL catholyte (CH3CN + 0.1 mM TBAP + 5.0 mM benzenyltrichloride), at 20℃.,a Applied potential vs. Ag/Ag+.
b In present of 1 M CH3COOH,Zhejiang University of Technology,,16,,3.2.氯乙酸,Fig. 3.2 CVs of three electrodes in blank 0.5 M NaOH (1(blue), 2, 3(red)) and in present of 50 mM TCAA (1(black, red and green)) or 50 mM MCAA (2, 3(black)), v = 50 mV s-1, T = 298 K.,,,J. Electroan. Chem., 2012, 664: 39.,Zhejiang University of Technology,CCl3COOH (TCAA),CH2ClCOOH (MCAA),Ag(p),Ag(r),17,Fig. 3.3 CVs of Ag(r) electrode in blank aqueous solutions + (1) 0.05 M TCAA, (2) 0.05 M DCAA, (3) 0.05 M MCAA, (4) nothing, at 50 mV s-1.,,,,Zhejiang University of Technology,1---CCl3COOH
(TCAA)
2---CHCl2COOH
(DCAA)
3---CH2ClCOOH
(MCAA)
4---blank,pH = 2.2,pH = 7,18,Fig. 3.4 The reduction of TCAA (0.05 M) using Ag (r) electrode, at 298 K, in aqueous solutions of (1) 0.5 M H2SO4, (2) 0.5 M Na2SO4 and (3) 0.5 M NaOH.,Fig. 3.5 Current efficiency for the reduction of 0.05 M TCAA, using Ag (r) electrode (2 cm × 3 cm × 0.1 cm), using applied current 110 mA, (1) 0.5 M H2SO4, (2) 0.5 M Na2SO4 and (3) 0.5 M NaOH.,Zhejiang University of Technology,,19,,,Fig.3.6 SEM: (1) Ag(p) electrode, (2) Pd/Ag(p) electrode, (3) Ag(r) electrode, and (4) Pd/Ag electrode.,3.3. 2,4-二氯苯氧乙酸,Electrochem.Commun., 2009, 11: 2133;
Electrochim. Acta, 2013, 96: 90.,Zhejiang University of Technology,Ag(p) electrode,Ag(r) electrode,Pd/Ag(p) electrode,Pd/Ag(r) electrode,20,,Fig. 3.7 CVs of five electrodes in blank 0.5M NaOH (a, b, c, d(black), f(black)) and in presence of 25 mM 2,4-D (d(red, green), e, f(red)), ν = 50 mV s-1.,Zhejiang University of Technology,21,Table 3.2 Electroreductions of 25 mM 2,4-D in 0.5 M NaOH, on four different electrodes (3×4 cm2). PAA: phenoxyacetic acid; ClPAA: 2-Cl and 4-Cl-phenoxyacetic acid; 2,4-D: 2,4-diCl-phenoxyacetic acid.,Zhejiang University of Technology,22,Zhejiang University of Technology,Fig. 3.8 The product selectivity and carbon mass balance during the ECH dechlorination of 2,4-D.,Fig. 3.9 The hydrodechlorination mechanism on Pd/Ag(r) electrode,23,4.总结和展望,Zhejiang University of Technology,通过改变催化剂类型和电解液pH，很多氯代有机物氢化脱氯反应的选择性有望得到有效控制；
银催化剂适合需要控制区域选择性的氢化脱氯反应，钯催化剂适合需要控制化学选择性的氢化脱氯反应；
钯银双金属有望成为高活性的选择性氢化脱氯反应催化剂。,电化学氢化脱氯反应选择性的本质机理；
电化学选择性氢化脱氯用其他金属催化剂的开发，比如其他廉价金属或含少量贵金属的合金的开发；
银、钯催化的电化学选择性氢化脱氯反应的应用开发。,24,致 谢,Zhejiang University of Technology,国家自然科学基金委
国家973计划
浙江奥复托化工有限公司
浙江埃森化学有限公司
马红星、丁旭芬、蔡倩倩、马昊等同学,25,Zhejiang University of Technology,敬请批评指正！,26,
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