Kinetic study of the nitrosation of N-alkylureas in dioxane-acetic acid mixtures

✍ Scribed by Guillermo González Alatorre; Javier G. Zapiain S.; Pedro A. Quintana H.; Gloria M. Martínez G.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 159 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:2<145::aid-kin6>3.0.co;2-s

✦ Synopsis

The rate constants were determined for the nitrosation reactions of the following substrates: Methyl (MU), Ethyl (EU),Propyl (PU)Butyl (BU), and Allylurea (AU). The rate equation found at a constant pH was:

[Urea]. The reactions were carried out in pre-v ϭ k[HNO ] 2 dominantly organic media(dioxane-acetic acid-water) with differing polarities. The proposed reaction mechanism involves the proton transfer from the protonated N-alkyl-N-nitrosourea to the acetate anion. As the polarity of the medium decreased, an approximation of the rate constants of the nitrosation of the different substrates was observed. This approximation can be interpreted as a function of the impediment generated by the R alkyl radical in the rate controlling step. Accordingly, the substrate reactivity will be associated with the ease in which the protonated N-alkyl-N nitrosurea can transfer the proton to the acetate anion. The results achieved in this study are in accordance with there activities observed in the nitrosation of these substrates in aqueous media