Dithiooxamide

Dithiooxamide, also known as rubeanic acid, is an organic compound with the formula C_2H_4N_2S_2. It is a colorless solid that is soluble in polar organic solvents. Dithiooxamide is primarily used as a chelating agent in analytical chemistry for the detection of metal ions. It forms colored complexes with many metal ions, which can be used to identify or quantify the presence of these ions in a sample.

Properties

Dithiooxamide has a molecular weight of 120.20 g/mol and a melting point of 196-198 °C. It is relatively stable under normal storage conditions but should be protected from moisture. In solution, dithiooxamide can undergo hydrolysis, especially in the presence of strong acids or bases, leading to degradation of the compound and loss of its chelating abilities.

Synthesis

Dithiooxamide can be synthesized from 1,2-diaminoethane (ethylenediamine) by treating it with carbon disulfide in an alkaline medium. The reaction proceeds through the formation of a dithiocarbamate salt, which is then acidified to yield dithiooxamide.

Applications

Analytical Chemistry

In analytical chemistry, dithiooxamide is used as a sensitive and selective reagent for the detection of metal ions, such as copper, nickel, and cobalt. The compound forms colored complexes with these metals, which can be detected visually or spectroscopically. This property is utilized in qualitative and quantitative analysis of metal ions in various samples, including water, soil, and biological materials.

Metal Extraction

Dithiooxamide has applications in the extraction and recovery of metals. Its ability to form stable complexes with certain metal ions is exploited in hydrometallurgy for the selective extraction of metals from ores and waste materials.

Safety

Dithiooxamide should be handled with care, as it can cause irritation to the skin, eyes, and respiratory tract. Appropriate personal protective equipment, such as gloves and goggles, should be worn when handling the compound. It should be stored in a cool, dry place, away from incompatible materials such as strong oxidizing agents.

See Also

• Chelation
• Analytical chemistry
• Metal ions in aqueous solution