邻联茴香胺的电化学和薄层光谱电化学研究

采用电化学和薄层光谱电化学方法，以三电极系统在酸性介质中对邻联茴香胺（ODA）电氧化性质进行了研究，测得邻联茴香胺的克式量电位，电子转移数和扩散系数，实验结果表明，邻联茴香胺在铂网栅电极上的电氧化为可逆的两电子转移过程。     

离子液体BMIMBF4中对甲氧基甲苯的电化学氧化

以离子液体1-丁基-3-甲基咪唑四氟硼酸盐(BMIMBF4)为电解质,采用循环伏安法(CV)、计时电流法(CP)、原位傅里叶变换红外光谱(in situ FTIRS)法等手段研究了对甲氧基甲苯(p-MT)在铂电极上的电氧化行为.实验结果表明:对甲氧基甲苯在离子液体中的电化学氧化反应是受扩散控制的四电子不可逆过程,估算了其扩散系数D=3.4×10-7cm2.s-1,主要电氧化产物为茴香醛,加入适量的水或适当提高温度有利于电氧化反应向生成相应醛的方向进行.     

对甲基茴香醚和茴香醛的气相色谱法分离分析

采用OV 101毛细柱对由对甲基茴香醚间接电氧化合成茴香醛的产物进行了分离分析,内标法定量,苯甲酸乙酯为内标物,反应物对甲基茴香醚和产物茴香醛均在0.5～4.0g/L范围内呈良好的线性关系,检测限分别为8.1ng和12.4ng。     

电化学氧化法合成茴香醛（Ⅲ）──茴香脑合成茴香醛的反应动力学

报道了茴香脑电氧化合成茴香醛的表现活化能（约２３ｋＪ／ｍｏｌ）、反应控制步骤和反应历程，导出了符合一级反应的速率方程。     

碱性溶液中苯甲醇的选择性电催化氧化研究

采用循环伏安法和恒电流电解法, 以铂、镍、铜电极为工作电极, 研究了苯甲醇在碱性溶液中的电氧化行为. 用GC-MS和HPLC检测恒电流电解产物, 在镍电极上苯甲醇可选择性地氧化为苯甲醛; 在铂电极上主要产物为苯甲酸; 在铜电极上则有苯甲酸和苯甲醛两种产物. 通过循环伏安探讨了扫描速度、底物浓度及温度等因素对镍电极上电化学行为的影响. 实验结果表明, 在镍电极上苯甲醇的氧化反应为不可逆反应, 受吸附步骤控制, 其反应的活化能E_a为39.72 kJ•mol^－1. 采用原位红外光谱法研究了碱性溶液中苯甲醇在镍电极上的反应机理, 同时也进一步证实了其氧化产物为苯甲醛.     

异黄樟油素在铂电极上电氧化及原位拉曼光谱

利用循环伏安法(CV)研究了异黄樟油素在铂电极上的电氧化行为,当在－0.55～1.95 V（vs Ag/AgCl电极）电位范围内进行扫描时,其CV图有两个氧化峰和一个还原峰出现;比较了异黄樟油素和黄樟油素这对异构体在铂电极上的电氧化行为;探讨了异黄樟油素在铂电极上的电氧化反应机理.同时,通过开展原位表面增强拉曼光谱实验,确定了异黄樟油素的电氧化发生在烯丙基的碳碳双键上.     

硫酸高铈氧化茴香脑合成茴香醛的反应动力学研究

茴香醛被广泛用于食品、香料、医药及电镀等工业中[1]。制备茴香醛是用对甲氧基甲苯作为原料氧化合成茴香醛,[2,3]但近年石油化工原料价格猛涨,因而以我国广西盛产的茴香油(含茴香脑)为原料制备茴香醛的方法得以重视[4-9]。用间接电氧化法氧化茴香脑(anethole)制备茴香醛(ani-s     

硝基苯在离子液体EMimBF4中的选择性电还原

采用循环伏安法和恒电位电解法研究了离子液体EMimBF4中硝基苯在微铂电极上的选择性电还原特性. 研究结果表明, 硝基苯在铂电极上的电还原反应为双分子八电子三步骤电化学过程: 第一步反应为准可逆单电子转移步骤, 产生阴离子自由基; 第二步为二电子转移步骤, 并伴有随后的双分子不可逆自由基偶合反应和快速质子化及脱水反应, 主要产物为氧化偶氮苯; 第三步是二电子转移产生偶氮苯的过程. 通过控制电位, 可以选择性地合成氧化偶氮苯和偶氮苯; 在EMimBF4中, 硝基苯和水的浓度变化对电化学行为产生较大影响.     

金属化聚邻甲苯胺膜修饰电极的性能研究

在聚邻甲苯胺(POT)膜修饰电极上用电化学法沉积Pt微粒,由SEM与XRD表征其表面形态与晶面取向,同时研究异丙醇在金属化POT膜电极上的氧化行为.结果表明,Pt在POT膜上的沉积呈现晶面择优取向的现象,况且POT质子掺杂后,由于电化学活性增强,影响了沉积铂微粒的尺寸和粒径分布.异丙醇的电氧化可发生在POT的电化学活性区,当电位大于0.70 V(SCE)时,POT不再呈氧化还原活性,异丙醇的电氧化主要在铂微粒上进行.聚合物不仅作为铂微粒的载体而且自身参加反应,这种微异相催化体系需用新的模型描述.     

ODA-H_2O_2-HRP伏安酶联免疫分析新体系的研究

提出邻联茴香胺-H_2O_2-HRP伏安酶联免疫分析新体系,并用于测定HRP和HRP标记物.该方法是将HRP催化H_2O_2氧化邻联茴香胺的酶催化反应与邻联茴香胺的氧化产物的电极还原反应相偶合,在BR缓冲溶液中,在-0.56V(SCE)左右产生灵敏的极谱波.应用此极谱波测定HRP的检测限为3.7×10~(-12)g/mL,线性范围为1.O×1O~(-11)～2.0×10~(-9)g/mL.对邻联茴香胺-H_2O_2-HRP伏安酶联免疫分析新体系的偶合反应机理及电极还原过程进行了较详细的探讨.     

太阳能热电耦合合成苯甲酸

通过恒电位电解甲苯实现了苯甲酸的太阳能热电耦合合成, 考察了电极材料、 反应温度及电解电压对苯甲酸合成的影响. 采用气相色谱、 红外光谱和紫外光谱对电解产物进行分析检测, 证实了太阳能热电氧化甲苯的主要产物为苯甲酸. 实验结果表明, 以石墨作为阳极材料, 反应温度为90 ℃, 电解电压为2.0 V时, 氧化甲苯合成苯甲酸的产率可达51.6%.     

甲苯异构体在石墨电极上的直接电氧化

通过循环伏安法、电化学原位红外光谱和恒电位电解法研究了甲苯异构体在0.05 mol/L硫酸体系中的直接电氧化行为. 结果表明, 对甲氧基甲苯、对甲基甲苯、对氯甲苯和对叔丁基甲苯4种含不同取代基的甲苯异构体具有相似的电氧化行为, 均在1710 cm^-1左右出现向下的羰基伸缩振动峰(υ_C=O), 在1130 cm^-1左右出现向上的甲基消耗峰. 通过气相色谱-质谱法(GC-MS)对恒电位电解产物进行检测, 进一步证实了在石墨电极、硫酸水溶液体系中甲苯异构体直接电氧化主要产物为相应的芳香醛, 40 ℃时, 对甲氧基苯甲醛的产率为70.9%.     

多晶铂电极表面硫吸附物种的原位表面增强拉曼光谱研究(英文)

本工作首次报道了在酸性或碱性电解质中高粗糙度多晶铂电极表面硫物种的吸附、电氧化过程的原位表面增强拉曼光谱研究.分别在两种情况下采集了粗糙铂电极的表面增强拉曼光谱:(a)循环伏安处理后控制一定电位(0.2V)下;(b)逐步控制不同电位.酸性电解质条件下,两种情况均观察到位于300cm-1的Pt—S振动.Pt—S键较强,阻止了氢在铂电极表面的吸附,需多次循环伏安处理才能完全将表面吸附的硫去除.同时还观察到位于470cm-1处的少量多聚S物种(S8或者其他类型).这些多聚S物种仅仅微弱地键合在铂电极的表面,可以容易地除去.在碱性电解质中,同样也在(a)和(b)情况下观察到位于310cm-1的Pt—S振动吸收.本工作了获得了有关硫在粗糙多晶铂电极表面吸附和电氧化重要信息,证明了原位表面增强拉曼光谱在研究铂表面的适用性.     

Immobilization of invertase in conducting copolymers of 3-methylthienyl methacrylate

Immobilization of invertase in conducting copolymer matrices of 3-methylthienyl methacrylate with pyrrole and thiophene was achieved by constant potential electrolysis using sodium dodecyl sulfate (SDS) as the supporting electrolyte. Polythiophene (PTh) was also used in entrapment process for comparison. Kinetic parameters, Michaelis-Menten constant, K(m), and the maximum reaction rate, V(max), were investigated. Operational stability and temperature optimization of the enzyme electrodes were also examined.     

Theory of irreversible electrode reactions coupled to ion transfer across the liquid/liquid interface

Kinetically controlled electro-oxidation of a redox probe dissolved in the organic solvent, which is interposed between an electrode surface and an aqueous solution as a thin layer, is analyzed theoretically. It is demonstrated that the electrode reaction rate constant can be measured by the variation of scan rate in linear scan voltammetry both in the absence and in the superfluity of the supporting electrolyte dissolved in the film.Dedicated to Professor Dr. Alan M. Bond on the occasion of his 60th birthday     

C-H键选择性直接电氧化研究

C-H键是有机化合物中最基本的化学键,C-H键的活化和直接转化避免了反应物的预先官能化,是最终实现烷烃类化合物转化为不同种类有机化合物最直接、高效的转换方式,通过C-H键构建C-X键（X=O、C、N）是非常重要和具有挑战性的研究. C-H键直接电氧化活化过程中以“电子”参与反应,不需要加入额外的催化剂,并可通过选择合适的电极材料、支持电解质、溶剂和反应温度,通过恒电流或者恒电位电解,进行具有特定的反应选择性和区域选择性的C-H键电氧化活化,从而获得含其他活性基团的目标产物.     

Electronitiated polymerization of maleic anhydride by direct electron transfer

Controlled potential electrolysis was employed to accomplish homopolymerization of maleic anhydride, by direct electron transfer. The solvent used in the polymerization studies was acetonitrile–dimethylformamide mixture (1 : 1) with the supporting electrolyte tetrabutylammonium tetra fluroborate, A brown paramagnetic polymer was obtained from the catholyte, upon electroreduction of monomer.     

甲醇电氧化催化剂Pt/CeO2-CNTs与PtRu/C的比较研究

为认识合成催化剂Pt/CeO2-CNTs与商用催化剂PtRu/C(E-TEK)的催化性能和结构特点, 用CO溶出法和恒电位氧化法比较了这两种催化剂对CO的电氧化活性, 运用循环伏安法和恒电位氧化法比较了这两种催化剂对甲醇的电氧化活性. CO电氧化实验结果表明, PtRu/C上CO的电氧化活性明显优于Pt/CeO2-CNTs; 甲醇电氧化实验结果却表明, Pt/CeO2-CNTs与PtRu/C上甲醇电氧化表观活性相当. 为从结构特点上解释PtRu/C上CO电氧化和甲醇电氧化活性的不一致, 对PtRu/C进行了循环伏安扫描和CO溶出实验. 结果表明, PtRu/C的甲醇电氧化电流之所以没有预期高, 一是由于Pt比表面积不够大, 同时Pt-Ru之间协同作用有待提高. 本研究结果表明, 尽管Ru对Pt上CO电氧化有显著助催化作用, 但要充分发挥其对Pt上甲醇电氧化的助催化作用, 需同时提高Pt表面积和Pt-Ru接触界面. 该结论对设计甲醇电氧化催化剂具有普适意义.     

A Novel Non-phosgene Process for the Synthesis of Methyl N-Phenyl Carbamate from Methanol and Phenylurea： Effect of Solvent and Catalyst

A novel environmentally benign process for the synthesis of methyl N-phenyl carbamate (MPC) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to MPC increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n-octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to MPC while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied.     

Electrodecomposition in subcritical water using o-xylene as a model for benzene, toluene, ethylbenzene, and xylene pollutants

The possibility of the combination of electrolysis and subcritical water as a novel electrolyte was investigated. A stainless steel reactor was used as an undivided electrochemical cell containing platinum as the anode and a stainless steel reactor as the cathode. At first, the effect of temperature on the electrolysis current as the main parameter was studied in a cell containing only pure water and a supporting electrolyte. It was realized that the electrolysis current (and, consequently, the electrolysis efficiency) increased linearly with temperature because of the change in viscosity and other physicochemical properties of subcritical water. As a result, at 553 K the electrolysis efficiency was over 14-fold higher than that under ambient conditions. The possibility of the applicability of the above combined techniques for the decomposition of o-xylene was also followed as a model for benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. The effect of experimental conditions such as the electrolysis duration, the electrolysis voltage, and the temperature of subcritical water was investigated. Several decomposed products were identified. o-Xylene was directly electro-oxidized to 2-methylbenzyl alcohol and consecutively to the other oxidation products. Also, hydroxide ions were oxidized to oxygen molecules, where hydrogen was generated on the cathodic surface. The final oxidation product of the electro-oxidation reaction was identified as carbon dioxide. The results indicate that more than 95% of o-xylene can be decomposed under optimum conditions.