L. S. German

Electrochemical fluorosulfation of tetrafluoroethylene

Electrooxidation of certain fluoroolefins on platinum and glass-carbon in fluorosulfonic acid has been studied. The large difference in oxidation potentials of tetrafluoroethylene and the fluorosulfate anion makes it possible to carry out fluorosulfation via an ECEC mechanism. Potentiostatic preparative electrolysis at limiting-current potentials for oxidation of tetrafluoroethylene (E=1.5 V) yields a mixture of α,ω-bis-fluorosulfates which is almost quantitative with respect to current, the main component being 1,2-bis(fluoro-sulfato)tetrafluoroethane.

Electrochemical synthesis of perfluoroalkylacetones

The interaction of electrochemically generated radicals in the electrolysis of the perfluorocarboxylic acids RFCF2COOH (I), where RF=F (a), CF3 (b), C2F5 (c), C3F7 (d), C5F11 (e), and C7H15 (f), with isopropenyl acetate (II) was studied. The dependence of the results of the electrolysis on the adsorption capacity of the anode permits the proposition that the interaction of (II) with the ECG-radicals occurs close to the surface of the electrode. The yield of the perfluoroalkylacetones comprised 30–37%.

Localization of electrochemically generated radicals as a function of their structure and the nature of the solvent

The electrooxidation of different perfluorocarboxylic acids has been investigated in the presence of ethylene, on electrodes with different adsorbing power [platinum and glassy carbon (GC)] in different solvents. It has been shown that the reaction zone of the ECG radicals is determined by their solubility; depending on this, it can be limited to the electrode surface or encompass the entire volume of the solution. The concept of the solubility of the ECG radicals made it possible to establish some regularities in the formation of cross combination products in the Kolbe electrosynthesis of different perfluorocarboxylic acids.

Electrochemical synthesis of perfluoroalkylchlorides

Electrooxidation of perfluorocarboxylic acids in the presence of Cl2 yields perfluoroalkylchlorides RFCl. It is suggested that anodic oxidation of perfluorocarboxylate ions is the determining electrochemical stage in this electrochemical version of the Borodin-Hundsdikker reaction.

Electrochemical synthesis of branched dicarboxylic acids from oxalic acid and propylene

ConclusionsElectrolysis of methanolic solutions of oxalic acid in the presence of propylene on a platinum catalyst leads to a preparative yield of methyl esters of branched dicarboxylic acids, specifically, methylsuccinic, dimethyladipic, and trimethyloctanedioic acids.

Telomerization of ethylene by anodically generated chlorine

Conclusions1,2-Dichloroethane, 1,4-dichlorobutane, and bis (2-chloroethyl) ether were obtained by the reaction of ethylene and anodically generated chlorine radicals in methanol and in aqueous acetonitrile, and 1-methoxy-2-chloroethane was also obtained in methanol.

Electrosynthesis of diesters of saturated dicarboxylic acids from oxalic acid and ethylene

Conclusions1.The electrolysis of the methanolic solutions of oxalic acid on a Pt anode in the presence of ethylene under pressure produces a mixture of diesters of succinic acid, adipic acid, suberic acid, and sebacic acid with a preparative yield (70–95%).2.According to the data from the investigation of the kinetics of the electrooxidation of oxalic acid in the presence of ethylene, the latter does not take part in the electrochemical stage of the process. Being adsorbed on the surface of the electrode, ethylene participates in secondary reactions with electrochemically generated radicals.

Effect of electrolysis conditions on anodic trifluoromethylation of dimethyl maleate

Conclusions1.An increase in the dimethyl maleate concentration and a decrease in the current density leads to an increase in the yield of the products obtained by adding CF3 radicals to dimethyl maleate.2.The reaction for the trifluoromethylation of dimethyl maleate takes place in the pre-electrode layer.