Atrazine hydrogen-bonding potentials

Abstract

Formation constants for complexation between atrazine and four hydrogen-bond donors and four acceptors are obtained by linear regression of nuclear magnetic resonance chemical shift data. Since the donors and acceptors were selected from among the compounds used to establish relative hydrogen-bonding scales, these formation constants provide a measure of atrazine's relative donating (am) and accepting (¡3m) parameters. The calculated parameters (am = 0.42; /3m = 0.49) show that atrazine has intermediate reactivity toward donating and accepting hydrogen bonds with monofunctional complexing agents.

Adsorption of atrazine on hemp stem-based activated carbons with different surface chemistry

“…Moreover, if hydrogen bonding was a dominant mechanism of atrazine adsorption, then HAC HNO 3 and HAC NH 3 , which contain the highest oxygen and nitrogen contents, respectively, should show the highest adsorption capacity. The acid carboxylic groups on the surface of oxidized HAC and pyridinic, pyridonic and amide/lactam groups in aminated HAC are the most likely places where a strong effect of the hydrogen bonding mechanism would be observed (Welhouse and Bleam 1993). On the contrary, a significant decrease in atrazine uptake by oxygen-and nitrogen-rich HACs was revealed.…”

“…Many interactions, such as electrostatic interactions (Salvestrini et al 2010), hydrophobic effects and van der Waals forces (Tang et al 2012;Kulikova and Perminova 2002), p-p interactions (Zhao et al 2013), or hydrogen bonding (Welhouse and Bleam 1993;Kovaios et al 2006) have been reported to be involved in atrazine adsorption on various adsorbents. Atrazine is a weakly basic herbicide with a pK b of 12.3 (Table 1).…”

“…Under these conditions atrazine is adsorbed on the carbon surface as uncharged species, and as a result, electrostatic interactions may not influence its adsorption from aqueous solution. A study by Welhouse and Bleam (1993) emphasized the high hydrogen-bonding potential of atrazine molecules. In the triazine ring, the para nitrogen is a site where atrazine accepts a hydrogen bond, whereas the ethylamino side chain can be a hydrogen-bond donor.…”

“…In this context, further elucidating the interactions between atrazine and AC with different surface properties is an important step for the development of highperformance adsorbents for atrazine removal. Atrazine can act as a p electron donor and shows both H-bond donor and acceptor properties (Welhouse and Bleam 1993). The H-bonding mechanism plays an important role in the sorption of atrazine by soils and natural sediments (Kovaios et al 2006).…”

Sorption of Pesticides on Natural Geosorbents

“…deactivated bypyridilium ring of atrazine) (Senesi, 1992). An EDA mechanism between atrazine and soil organic matter has been postulated but the mechanisms are still a controversy (Martin-Neto et al, 1994, Welhouse & Bleam, 1993, Martin-Neto et al, 2001, Celano et al, 2008. EDA interactions between aromatic ring in trifluralin and soils aromatics seem possible but are likely to be weak (Shirzadi et al, 2008).…”