Electrocarboxylation Of Allyl Halid

The compounds of butenoic acid, which have been widely used as intermediate in organic synthesis, especially in the synthesis of medicine and dyestuff, are important materials for organic and chemical industry. So they present the satisfactory economical as well as social benefit. The conventional methods of the synthesis of butenoic acid bring the pollution and don't follow the improvement of the society. Electrochemisty is a green, clean and environment-friendly technology to the chemical industry. Atom economy became a popular topic and the concept of green chemistry was brought out. Organic electro-synthesis, which studies the synthesis of organic compound with electrochemical technologies and methods, uses electron as reagent to replace the conventional redox agent to carry out the synthesis of organic compound. It tries to avoid pollution from the beginning. To synthesize the butenoic acid from halogenated propene by electrochemical reduction gives some new ideas for the synthesis of the serial products of butenoic acid.CO₂ has a long history of use in organic synthesis because it is an inexpensive reagent that is available on a large scale. The thermodynamic stability and relative kinetic inertness of CO₂ require its preliminary activation,and electrochemical techniques provide some solutions to the problem. CO₂ has been activated either by direct (at the electrode) or indirect (through heterogeneous or homogeneous catalysis) reduction. Furthermore, examples of both redox and chemical homogeneous catalysis have been described. Most of the latter employed transition metals complexes, which can also promote the insertion of CO₂ into suitable organic substrates.The paper is divided into three main parts. In the first part, the electrochemical behavior of ally chlorid and 3-chloro-2-methyl-1-propene was discussed. Cyclic voltammetry, Differential Pulse Voltammetry and Chronocoulometry were used to study the electrochemical reduction behavior of ally chlorid and 3-chloro-2-methyl-1-propene on GC electrode. The results showed that the reduction of ally chlorid or 3-chloro-2-methyl-1-propene on GC electrode was a diffusion-controlled irreversible process. The diffusion coefficient D of ally chlorid in MeCN solution was 4.10×10^-5cm².s^-1, while the transfer coefficient was 0.23. The diffusion coefficient D of 3-chloro-2-methyl-1-propene in MeCN solution was 3.75×10^-5cm².s^-1, while the transfer coefficient was 0.22.In the second part, the optimized conditions for the preparation of 3-butenoic acid from ally chlorid by electrochemical method were studied. The electrochemical reduction of ally chlorid on copper electrode was a diffusion-controlled irreversible process. And the reduction peak current appeared at around -1.9V.The optimized condition of was: Copper as working electrode, Ag/AgI as reference electrode and Mg as auxiliary electrode, 10 ml MeCN with 0.lmol·L^-1 TBAI, 0.28mol·L^-1 ally chlorid was added, the electrolysis potential was -2.3V, the temperature was 273K. The yield was 55.65% with the theoretical electric quantity. Ti as working electrode, Mg as auxiliary electrode, 15 ml MeCN with 0.1mol·L^-1 TBAI, 0.36mol·L^-1 ally chlorid was added, under a constant current of 11.57 mA·cm^-2 until 2 F·mol^-1 of charge had passed through the cell at 273K, The yield was 70.59%.In the third part, the optimized conditions for the preparation of 3-methyl-3-butenoic acid from 3-chloro-2-methyl-1-propene by electrochemical method were studied. The electrochemical reduction of 3-chloro-2-methyl-1-propene on copper electrode was a diffusion-controlled irreversible process. And the reduction peak current appeared at around -1.9V.The optimized condition of was:Copper as working electrode, Ag/AgI as reference electrode and Mg as auxiliary electrode, 10 ml MeCN with 0.1mol·L^-1 TBAI, 0.26mol·L^-1 ally chlorid was added, the electrolysis potential was -2.5V, the temperature was 273K. The yield was 71.67% with the theoretical electric quantity. Ti as working electrode, Mg as auxiliary electrode, 15 ml MeCN with 0.1mol·L^-1 TBAI, 0.31mol·L^-1 ally chlorid was added, under a constant current of 11.65mA·cm^-2 until 4F·mol^-1 of charge had passed through the cell at 273K The yield was 88.29%.