US EPA

5933757 

Journal Article 

Kinetics of phthalate reactions with ammonium hydroxide in aqueous matrix 

Patnaik, P; Yang, M; Powers, E 

2001 

1 

Water Research
ISSN: 0043-1354
EISSN: 1879-2448 

PERGAMON-ELSEVIER SCIENCE LTD 

OXFORD 

35 

6 

1587-1591 

English 

11317906 

10.1016/S0043-1354(00)00401-2 

WOS:000167617900024 

https://search.proquest.com/docview/14579663?accountid=171501
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Common phthalate pollutants, such as dimethyl phthalate and diethyl phthalate found in aqueous environmental matrices react with ammonium hydroxide at ordinary temperatures exhibiting an overall reaction order in the range 1.3-1.4. While the reaction is of first order with respect to the phthalate, the order of reaction is fractional in ammonium hydroxide. The rate constants for the reactions of these two phthalates in alkaline waters at ambient temperatures are in the range 1.3 x 10(-4) and 8.5 x 10(-5) Lx/mol s. Under these conditions the estimated half-lives for dimethyl phthalate and diethyl phthalate at a concentration of each at 20 mg/L is 4.5 and 14 h, respectively. Other phthalates are expected to exhibit similar kinetics in their base hydrolysis with NH4OH. Thus, the presence of both the phthalate esters and ammonia or ammonium salts in the water under alkaline conditions may result in their self-removal by hydrolysis. 

dimethyl phthalate; diethyl phthalate; ammonia; rate constant; order of reaction; kinetics