Hydroxy propazine

CASRN 139-40-2 molecular formula CgHieClNs FW 241.37 Chemical/Physical. The hydrolysis half-lives of propazine in O.lM-HCl, buffer at pH 5.0, and O.lM-NaOH solutions at 20 °C were 7.7, 83, and 5.1 d, respectively. Propazine degraded to 2-hydroxy-4,6-bis(isopropylamino)-l,3,5-triazine (Burkhard and Guth, 1981). 

ChemicaPPhysical. In aqueous solutions, propazine is converted exclusively to hydroxylprop-azine (2-hydroxy-4,6-bisisopropylamino)-5 triazine by UV light (7, = 253.7 nm) (Pape and Zabik, 1970). In acidic aqueous soil-free systems, propazine hydrolysis is pH dependent and follows first-order kinetics. At 23.5 °C, the estimated hydrolysis half-lives at pH 2.0, 3.0, 4.0, and 5.0 were 9, 36, 141, and 550 d, respectively. The rate of hydrolysis also increased and decreased in the presence of organic matter and calcium salts, respectively (Nearpass, 1972). 

Silylation and alkylation are other methods of modifying triazines. An HMDS—TMCS mixture was used for the preparation of TMS derivatives [492]. Flint and Aue [493], who evaluated several reagents, recommended performing silylation with the aid of BSTFA by heating at 150°C for 15 min. Under these conditions, hydroxy derivatives of simazine, atrazine and propazine provided one large peak and few by-products, identified as mono-, di- and trisilyl derivatives 10% of OV-17 was used as the stationary phase. 

When excess acid is added to the system, H ions (actually hydro-nium ions) compete for adsorption sites (Equation 6) and displace the pesticide cations back into solution as shown in Figure 9 where the pH decreases from 4 to 1 for prometone. Again the process depends upon the pKa of the compound for example, propazine cations are not released until the pH decreases from 2 to 1 (Figure 9). When strongly acid exchange resins were used, the s-triazine cations released were in the hydroxy form, having been hydrolyzed at the resin surfaces (57). 

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