Sulfonylurea chemical hydrolysis

Carboxyhc acid ester, carbamate, organophosphate, and urea hydrolysis are important acid/base-catalyzed reactions. Typically, pesticides that are susceptible to chemical hydrolysis are also susceptible to biological hydrolysis the products of chemical vs biological hydrolysis are generally identical (see eqs. 8, 11, 13, and 14). Consequentiy, the two types of reactions can only be distinguished based on sterile controls or kinetic studies. As a general rule, carboxyhc acid esters, carbamates, and organophosphates are more susceptible to alkaline hydrolysis (24), whereas sulfonylureas are more susceptible to acid hydrolysis (25). 

Sulfonylureas are systemic herbicides absorbed by the foliage and roots. They act by inhibiting acetolactate synthase, a key enzyme in the biosynthesis of branched chain aminoacids." This results in stopping cell division and plant growth. The most important degradation pathways of sulfonylureas are chemical hydrolysis and microbial degradation. 

In the soil, there are two major pathways of sulfonylurea degradation [58] (a) chemical hydrolysis and (b) microbial degradation. The breakdown of sulfony-lureas in sterile soils is solely attributable to chemical hydrolysis, whereas breakdown in non-sterile soils is a combination of both microbial degradation and... 

Hydrolysis appears to be a very significant pathway for the fate of sulfonylurea pesticides in sediments and natural waters. Although these chemicals often have many different functional groups, the principal cleavage occurs at the sulfonylurea bridge. The reaction is highly pH dependent (Equation (17)) ... 

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