Issue 7, 2021

Nucleophilic degradation of diazinon in thermoreversible polymer–polymer aqueous biphasic systems

Abstract

Although aqueous biphasic systems have been largely investigated in the separation and/or purification of biocompounds, their potential as reaction media to design integrated reaction–separation processes has been less explored. In this work aqueous biphasic systems (ABSs) composed of polypropylene glycol of molecular weight 400 g mol−1 (PPG 400) and different polyethylene glycols (PEGs) were characterized, and investigated for integrated reaction–separation processes, i.e. in the nucleophilic degradation of diazinon and further separation of reaction products by taking advantage of the lower-critical solution temperature (LCST) behaviour of these ABSs. The nucleophilic degradation of diazinon was carried out in the monophasic regime at 298 K, after which an increase in temperature (up to 313 K) allowed the product separation by two-phase formation (thermoreversible systems). The reaction kinetics and reaction pathways have been determined. The reaction kinetic increases as the PEG molecular weight decreases, with the half-life values obtained being competitive to those previously reported using volatile organic solvents as solvent media and significantly higher than under alkaline hydrolysis. One reaction pathway occurs in ABSs comprising PEGs of higher molecular weights, whereas in the ABS composed of PEG 600 two reaction pathways have been identified, meaning that the reaction pathways can be tailored by changing the PEG nature. ABSs formed by PEGs of lower molecular weights were identified as the most promising option to separate the pesticide degradation products by simply applying changes in temperature.

Graphical abstract: Nucleophilic degradation of diazinon in thermoreversible polymer–polymer aqueous biphasic systems

Supplementary files

Article information

Article type
Paper
Submitted
23 nov 2020
Accepted
27 jan 2021
First published
27 jan 2021

Phys. Chem. Chem. Phys., 2021,23, 4133-4140

Nucleophilic degradation of diazinon in thermoreversible polymer–polymer aqueous biphasic systems

D. Millan, M. R. Almeida, A. F. C. S. Rufino, J. A. P. Coutinho and M. G. Freire, Phys. Chem. Chem. Phys., 2021, 23, 4133 DOI: 10.1039/D0CP06086K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements