Periodate oxidation electrolytic method

The oxidation of starch to starch dialdehyde is the most frequently studied process, with periodate being the most commonly used oxidant. An electrolytic method provides for continuous regeneration of the oxidant.327-328 The anode is usually made of lead328 or lead(IV) oxide.329-330 Cathodes are made of steel. A 99 1 Pb- Ag alloy anode and a steel cathode were used for preparation of starch... 

Sodium iodate, NaI03.—The iodate is a constituent of Chile saltpetre or sodium nitrate, and remains in the mother-liquor after crystallization of the nitrate. It is an important source of iodine. The salt can be prepared by oxidizing sodium iodide with sodium peroxide6 or by the electrolytic method,7 and also by the interaction of sodium iodide and periodate.8 It forms white crystals. 

It must be very difficult for anyone graduating now to realize how little was known about organo-transition metal chemistry in 1937. We were taught the extraction of the metals from their ores, the properties of their oxides and simple salts in terms of the Periodic Law, and a very little complex chemistry. Although Departments of Physical Chemistry were well established, they were still young, and physical methods other than electrolytic methods found very little application in the study of complicated organic or inorganic compounds. Infrared spectrometers were sophisticated and temperamental instruments, applied mainly to... 

Greater utilization of periodate as an oxidant has been suggested in the development of an electrolytic method (228) starch is oxidized in 2 % sulfuric acid containing iodic acid. This method is similar in concept to the electrolytic bromine method of Isbell and Frush 179),... 

Oxidation of a glycol can lead to a variety of products. Periodic acid quantitatively cleaves 1,2-glycols to aldehydes and is used as an analysis method for glycols (12,13). The oxidation of propylene glycol over Pd/C modified with Pb, Bi, or Te forms a mixture of lactic acid, hydroxyacetone, and pymvic acid (14). Air oxidation of propylene glycol using an electrolytic crystalline silver catalyst yields pymvic aldehyde. 

A novel method for the electrolytic regeneration of periodate ion in oxidizing solutions has been reported.240 This procedure shows industrial promise, since it circumvents the initial, high cost of periodates. 

Of the older methods for the preparation of periodic acid, the most satisfactory for obtaining large quantities is the electrolytic oxidation of iodic acid at an anode of platinum plated with lead dioxide, the cathode solution being dilute nitric acid.1 The iodic acid for this preparation is conveniently prepared by the electrolytic oxidation of iodine.1 However, periodic acid prepared in this way often contains... 

Perbromates are obtained by oxidation of bromates in aqueous solution. Electrolytic oxidation, the best method of preparing perchlorates and periodates, is not very satisfactory in the case of perbromates. The most practical synthesis involves oxidation with elemental fluorine in sodium hydroxide solution. The procedure is somewhat hazardous, and the experimenter should familiarize himself with the precautions necessary for safely handling fluorine before undertaking the synthesis.1... 

In 1963 Dr. Danbk joined the Institute of Inorganic Chemistry of the Slovak Academy of Sciences in Bratislava, of which he was the director in the period 1991-1995. His main field of interest was the physical chemistry of molten salts systems in particular the study of the relations between the composition, properties, and structure of inorganic melts. He developed a method to measure the electrical conductivity of molten fluorides. He proposed the thermodynamic model of silicate melts and applied it to a number of two- and three-component silicate systems. He also developed the dissociation model of molten salts mixtures and applied it to different types of inorganic systems. More recently his work was in the field of chemical synthesis of double oxides from fused salts and the investigation of the physicochemical properties of molten systems of interest as electrolytes for the electrochemical deposition of metals from natural minerals, molybdenum, the synthesis of transition metal borides, and for aluminium production. 

Consequently, a series of experiments were conducted to measure the rate of XAs3+ oxidation by dissolved O 2 as a function of pH at 25° and 90°C. Experiments were conducted in 1.0-liter glass kettles, and temperatures were controlled to 1°C with heating mantles. Carbon dioxide-free air was continuously bubbled through the solutions to maintain PO2 = 0.2 atm. The initial XAs3 + concentration was 10-4-0 M, and the background electrolyte was 10-2.0 M NaCl in all experiments. To measure rates, samples were removed periodically from the kettles and total As and XAs concentrations were determined by the molybdate-blue method of Johnson and Pilson (28). The concentrations of XAs3+ were determined by diffaence. 

Three electroanalylical methods ai c based on electrolytic oxidation or reduction of an analyte for a sufficient period to assure its guantiUitive conversion to a new oxidation state. These methods are constanl-poieniial coulometry consiant-curre.ut coulometry, or coulometric titration and electrogravimetty. In eleclrogravi-metric methods, the product of the electrolysis is weighed as a deposit on one of the electrodes. In the two coulometric procedures, on the other hand, the ifuantiiyof electricity needed to congdete the electrolysis is a measure of the amount of analyte present. 

---