电化学选择性氢化脱氯反应

1、电化学选择性氢化脱氯反应第一页，共25页。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 Technology2第二页，共25页。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 TechnologyRondinini S., et al. Electroreduction of Halogenated O

2、rganic 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第三页，共25页。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; C

3、hen G.,et al. J. Phys. Chem. B, 2006, 110: 4863.Fig. 1.1 The hydrodechlorination mechanism on silver electrodeFig. 1.2 The hydrodechlorination mechanism on palladium electrode4第四页，共25页。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 Technology5第五页，共25页。Fig. 2.1 CVs of 3,5,6-T (a) at fo

4、ur 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 2014

5、10264884.1Zhejiang University of Technology2.1. 银催化Ag(p)Ag(r)pH = 3Ag(r)6第六页，共25页。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 ca

6、thodes.EntryCathodesIappa or EappaSolution pHFinal product distribution (%)Current efficiency (%)b3,5-D selectivity (%)c3,6-D selectivity (%) c3,5-D3,6-D3,5,6-T1Ni10 mA30098.20002Cu10 mA30098.50003Ag(p)1.0 mA32.50.895.42.554.317.44GC1.0 mA30094.40005Ag(r)10 mA344.02.649.344.086.85.16Ag(r)-1.1 V13.30

7、.437.896.27Ag(r)-1.1 V110.922.688.78Ag(r)-0.93 V735.415.347.235.467.029.09Ag(r)-0.73 V339.52.458.039.594.05.7010Ag(r)10 mA0.20098.7000a 2 Fmol-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

8、,5-D and 3,6-D selectivity calculated with respect to the converted 3,5,6-T.Zhejiang University of Technology7第七页，共25页。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 elec

9、trodes (2.5 cm3 cm).Zhejiang University of TechnologypH = 3 Ag(r)8第八页，共25页。Zhejiang University of TechnologyFig. 2.3 Effects of pH on the selectivity for hydrodechlorination of TeCP on silver cathodes. 9第九页，共25页。Fig. 2.5 LSV of Ni foam, Ag mesh, Cu foam electrodes, and Pd/Ni foam, Pd/Ag mesh, Pd/Cu

10、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 Technology2.2. 钯催化Pd/Ni foamNi foamAg meshCu foamPd/Ag m

11、eshPd/Cu foam10第十页，共25页。EntryCatholyte pH Final product distribution (%)CE c (%)3,6-DPA3-ClPA6-ClPA11.25M NaOH14096.13.1087.220.25 M NaOH11.513.5088.710.6084.030.5 M KH2PO4 + 0.3 M NaOH7.29.413.856.527.90.362.240.5 M KH2PO4 + 0.2 M NaOH4.46.647.336.450.5 M KH2PO4 + 0.2 M NaOH90.3

12、2.3081.76d 0.75 M H2SO4 + 20 % v/v Ethanol0086.9Table 2.2 Effect of electrolyte composition on the ECH dechlorination of 0.25 M 3,6-D.aa Cathode: a Pd/Ni foam (Projected area: 26 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 divid

13、ed fashion during the first hour of electrolysis due to its poor solubility.Zhejiang University of Technology11第十一页，共25页。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 )

14、 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 Technology1.25 M NaOH 0.75 M H2SO4 12第十二页，共25页。Scheme 1 Proposed mechanisms for the ECH dechlorination of 3,6-D.Zhejiang University of Technology13第十三页，共25页。Fig. 2.7 Effects o

15、f cathode catalysts and pH on the selectivity for hydrodechlorination of TeCP.Zhejiang University of Technology14第十四页，共25页。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 ( 2 mm), at 298K, v = 100 mV s-1, T = 20 . 物理化学

16、学报, 2013, 29: 973.Zhejiang University of TechnologyAg electrodeAg electrode15第十五页，共25页。EntryEappa(V)Final product distribution1-1.317% (5), 48% (4E), 35% (4Z)2-1.862% (10), 21% (11E), 17% (11Z)3b-1.292% (10), 8% (toluene)Table 3.1 Electroreduction of benzenyltrichloride at Ag mesh (2.53.0 cm2), in 4

17、0 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 CH3COOHZhejiang University of Technology16第十六页，共25页。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 a

18、nd 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 TechnologyCCl3COOH (TCAA)CH2ClCOOH (MCAA)Ag(p)Ag(r)17第十七页，共25页。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)

19、nothing, at 50 mV s-1.Zhejiang University of Technology1-CCl3COOH (TCAA)2-CHCl2COOH (DCAA)3-CH2ClCOOH (MCAA)4-blankpH = 2.2pH = 718第十八页，共25页。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

20、 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 Technology19第十九页，共25页。 Fig.3.6 SEM: (1) Ag(p) electrode, (2) Pd/Ag(p) electrode, (3) Ag(r) elect

21、rode, 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 TechnologyAg(p) electrodeAg(r) electrodePd/Ag(p) electrodePd/Ag(r) electrode20第二十页，共25页。Fig. 3.7 CVs of five electrodes in blank 0.5M NaOH (a, b, c, d(black), f(bl

22、ack) and in presence of 25 mM 2,4-D (d(red, green), e, f(red), = 50 mV s-1.Zhejiang University of Technology21第二十一页，共25页。EntryCathodesFinal product distributionCurrentEfficiency (%)Current (mA)/time (h)1Pd/GC1.7% PAA, 98.3% 2,4-D1.650/22Pd/Ag(p)9.9% PAA, 49.6% ClPAA, 40.5% 2,4-D37.250/23Pd/Ag(r)-PdC

23、l217.7% PAA, 37.3% ClPAA, 45.0% 2,4-D77.925/24Pd/Ag(r)-PdCl237.4% PAA, 49.1% ClPAA, 13.5% 2,4-D66.450/25Pd/Ag(r)-PdCl225.3% PAA, 37.2% ClPAA, 35.5% 2,4-D31.475/26Pd/Ti6.8% PAA, 6.1% ClPAA, 87.1% 2,4-D21.125/27Pd/Ti5.7% PAA, 5.5% ClPAA, 88.8% 2,4-D9.150/28Pd/Ti4.5% PAA, 4.9% ClPAA, 90.6% 2,4-D5.075/2

24、9Pd/Ag(r)-PdSO410.1% PAA, 46.5% ClPAA, 43.4% 2,4-D71.525/210Pd/Ag(r)-PdSO426.2% PAA, 48.1% ClPAA, 25.7% 2,4-D53.950/211Pd/Ag(r)-PdSO412.4% PAA, 32.3% ClPAA, 55.3% 2,4-D20.475/2Table 3.2 Electroreductions of 25 mM 2,4-D in 0.5 M NaOH, on four different electrodes (34 cm2). PAA:phenoxyacetic acid; ClPAA: 2-Cl and 4-Cl-phe