Abstract
Conductometry of aluminum with EDTA and NTA as well as oxalic, succinic, and benzoic acids in DMF (dimethyl formamide) has been investigated. Chelatometry with EDTA for the determination of aluminum in aqueous solution was not easy or rapid because Al was present in various types of anion in the solution. In DMF solution, AlCl3 was present in cations such as [AlCl3-x⋅DMF]+. After a large amount of DMF was added to the solution, conductometric titration of AlCl3 was made with DMF solution of carboxylic acid derivatives (oxalic, succinic, benzoic acids, NTA, and EDTA), and 3 inflection points were observed for each solute in DMF as follows:
Al: oxalic acid 2:1, 1:1, and 2:3
Al: succinic acid 2:1, 1:1, and 2:3
Al: benzoic acid 1:1, 1:2, and 1:3
Al: NTA 3:1, 2:1, and 1:1
Al: EDTA 4:1, 2:1, and 1:1
However, the inflection points for EDTA 2:1 and 1:1 were considered to be weak, and Al was determined by the point of 4:1.
The determination of aluminum in oxalic acid, phosphoric acid, sulfuric acid and other aluminum surface finishing solutions were rapidly determined by the present method after a large amount (10 times of the sample solution) of DMF was added.
