Photodecomposition of DDA

Area of Science:

• Environmental Chemistry
• Photochemistry
• Analytical Chemistry

Background:

• DDT and its derivatives are persistent organic pollutants.
• Understanding the environmental fate of these compounds is crucial for risk assessment.
• Photodegradation is a significant environmental transformation process.

Purpose of the Study:

• To investigate the photodecomposition pathways of 2,2-bis (p-chlorophenyl) acetic acid (DDA) in aqueous solutions.
• To identify the photoproducts formed during DDA degradation.
• To evaluate the suitability of HPLC for analyzing these compounds.

Main Methods:

• Photolysis of aqueous DDA solutions under laboratory and sunlight conditions.
• Identification and quantification of parent compounds and photoproducts using High-Pressure Liquid Chromatography (HPLC).
• Analysis of related compounds like p,p'-Dichlorobenzilic acid, p,p'-dichlorobenzhydrol, bis-(p-chlorophenyl) methane (DDM), and chlorogenzilate.

Main Results:

• DDA photodecomposition produced p,p'-dichlorobenzophenone (DCB), p-chlorobenzaldehyde, p-chlorophenol, and other polar products.
• DCB and p-chlorobenzaldehyde were resistant to photodegradation but slowly formed p-chlorobenzoic acid.
• HPLC proved effective for separating and quantifying DDA and its photoproducts in aqueous samples.

Conclusions:

• DDA undergoes photodecomposition in water, yielding various transformation products.
• The study elucidates a potential environmental degradation pathway for DDT-related compounds.
• HPLC is a valuable analytical tool for monitoring these pollutants and their degradation.