Nitrosation Reactions in Water/AOT/Xylene Microemulsions

• Published in: Industrial & engineering chemistry research Vol. 45; no. 2; pp. 600 - 606
• Main Authors: García-Río, L, Hervés, P, Mejuto, J. C, Rodríguez-Dafonte, P
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 18-01-2006
• Subjects: Applied sciences; Chemical engineering; Exact sciences and technology; Microemulsion; Nitrosation
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie050925t

A kinetic study of the nitroso group transfer from N-methyl-N-nitroso-p-toluenesulfonamide (MNTS) to the secondary amines piperazine (PIP) and N-methylbenzylamine (NMBA) in water/AOT/xylene and water/AOT/isooctane microemulsions was carried out. The water/AOT/xylene system is nonpercolative by effect of the decreased ability of the aromatic continuous medium to penetrate into the microemulsion interphase. The kinetic study was conducted at 50 °C (i.e., above the percolation temperature for water/AOT/isooctane microemulsions). The kinetic parameters for the reactions involved were determined by using the pseudophase model. This model assumes that the reactants partition between the three pseudophases in the microemulsion (viz., water, oil, and the interphase) as a function of their solubility and provides a quantitative explanation for the experimental behavior observed. In all cases, the reaction takes place at the microemulsion interphase. Also, the bimolecular rate constants, k 2 i , differ markedly between the two types of microemulsions. The difference can be ascribed to the differential polarity of the reaction medium. The activation parameters for the reactions of MNTS with PIP and NMBA in water/AOT/isooctane microemulsions were calculated.