Electrosyntheses Of 4 Aromatic Derivatives On 3 M-PTFE Modified Electrodes

Aromatic derivatives are the common and important chemical raw materials,and the traditional organic synthetic approaches are employed in their preparations commonly.However,many problems are emerged in synthetic processes such as complex processes,many by-products,serious environmental pollution and high costs.The preparation methods of aromatic derivatives are designed to electrosynthesis approaches while hydrophobic modified electrodes are utilized to improve their current efficiencies.The electrosyntheses belong to the"green chemistry"methods,which only involve the gain and loss of electrons.It has become the focus of organic synthesis direction at present,and has attracted much attention of scientific researchers and the industrial fields of fine chemicals.In this study,3 M-PTFE modified electrodes contained Ni,Cu and Pb were prepared by double anode composite electroplating using PTFE(polytetrafluoroethylene).3M-PTFE modified electrodes were applied to the electrochemical syntheses of2,3-dimethylpyridine,3-pyridinemethanol and p-hydroxybenzaldehyde to prepare quinolinic acid(2,3-pyridine-dicarboxylic acid),nicotinic acid(3-pyridinecarboxylic acid),p-hydroxy-benzyl alcohol(the main of gastrodia crystal)and parabenzoic acid(p-hydroxybenzoic acid).The electrochemical parameters such as CV,Tafel polarization curve and AC impedance of 3 M-PTFE modified electrodes in 3 aromatic derivatives electrolytes were tested by electrochemical workstation.The current efficiency and conversion of organic electrosynthesis reaction were calculated by chronoamperometric method.Finally,~1H NMR,FT-IR,MS and elemental analysis were used to characterize 4electrosynthetic products.The experimental results showed that the 3 M-PTFE modified electrodes had been better selectivity,electrocatalytic activity and electrode stability than the corresponding pure metal electrodes in the aromatic electrolyte.The electrooxidation conversion rate of3-pyridine methanol on Pb-PTFE modified electrode was up to 93.4%;the electrooxidation and electroreduction conversion rates of 2,3-dimethylpyridine and p-hydroxybenzaldehyde on Cu-PTFE modified electrode reached 87.4%and 93.6%respectively;the conversion of p-hydroxybenzaldehyde on the Ni-PTFE modified electrode was 85.8%.In this experiment,Zsimpwin software was applied to fit the measured AC impedance parameters,and the corresponding equivalent circuits were simulated to infer the interfacial models between M-PTFE modified electrode and solution in their electrochemical processes.