Polarography of Bis(aminophenyl)arsinic Acids, Phenylarsonic Acid and Arsanilic Acids

Abstract

Abstract 1) Polarographic behaviors of bis(aminophenyl)arsinic acids, phenylarsonic acid and arsanilic acids, were examined with dropping mercury electrode. 2) The reduction wave of bis(aminophenyl)arsinic acids appearing on the acid side is an irreversible three-electron reduction and this reduction mechanism is considered to be of the following type. (Remark: Graphics omitted.) 3) An assumption was forwarded in the preceding paper that the 2nd wave shown by bis(nitrophenyl)arsinic acids on the acid side may contain a reduction wave owing to the reduction of arsenic and that it is more likely to be a three-electron rather than a 4-electron reduction. The foregoing results obtained with bis(aminophenyl)arsinic acids suggest that it would be more appropriate to consider an irreversible, three-electron reduction. 4) The reduction waves shown by phenylarsonic acid and arsanilic acids on the acid side are an irreversible, four-electron reduction and the reduction mechanism may be assumed as follows: (Remark: Graphics omitted.) 5) Compounds like phenylarsinic acid (IX) do not exhibit a reduction wave at the dropping mercury electrode. (Remark: Graphics omitted.) 6) Summarizing the foregoing facts, it may be concluded that these organic arsenic compounds which show a reduction wave at the dropping mercury electrode are quiquevalent arsenic compounds, the reduction wave is that of quinquevalent to tervalent, and that the compounds not possessing As=O are not reduced. 7) The limiting current of these compounds in the acid side is controlled by the diffusion process and is in proportiona.1 relationship with the concentration, so that it can be utilized for quantitative analysis.