Electroorganic Synthesis Engineering

Abstract

Historically, electrochemical processes have been limited to the production of inorganic compounds, and commercial processes based on electroorganic synthesis have found only limited application. It appeared to be an “odious truth” (Fry, 1972) that electrochemical techniques were ignored in organic synthesis. But the past 25 years have witnessed the introduction of a fairly large number of new electroorganic processes with attendant advances in electrochemical process analysis. The most remarkable has been Monsanto’s highly successful electrochemical route for the production of adiponitrile. A particularly notable advance is the electrosynthesis of fine chemicals and natural products. Combinations of electrosynthesis with other strategies of rate or selectivity enhancement such as catalysis by PTC and by enzymes (Chapters 19 and 20) are also adding exciting possibilities to organic synthesis. Simultaneously, fundamental understanding of the principles of organic electrochemistry, electrode kinetics, and transport processes in electrochemical systems has grown rapidly in the last decade. A number of books and reviews have appeared on electroorganic chemistry during this period, for example, Eberson and Schafer (1971), Fry (1972), Beck (1974), Perry and Chilton (1976), Rifi and Covitz (1975, 1980), Weinberg (1974, 1990), Swann and Alkire (1980), Kyriacou (1981), Fletcher (1982), Baizer and Lund (1983), Baizer (1973, 1984), Shono (1984), Fletcher and Walsh (1990), Little and Weinberg (1991), Bowden (1997), Bockris (1998), Hamann (1998). This period also saw the emergence of electrochemical reaction engineering as a distinct discipline of chemical reaction engineering, as evidenced by a number of books and reviews on the subject, for example, Picket (1979), Udupa (1979), Danly (1980, 1984), Alkire and Beck (1981), Weinberg et al. (1982), Alkire and Chin (1983), Fahidy (1985), Mine (1985), Goodridge et al. (1986), Rousar et al. (1986), Heitz and Krysa (1986), Ismail (1989), Scott (1991), Prentice (1991), Goodridge and Scott (1995). Electroorganic synthesis offers opportunities for performing many of the conventional organic reactions at controlled rates and greater product selectivities without the addition of any catalyst. The processes almost always employ milder conditions and are characterized by greatly reduced air and water pollution. Further, there are a number of syntheses that can only be carried out electrochemically, such as the Kolbe synthesis and electrochemical perfluorination.