VINCLOZOLIN

Air & Water Reactions

Hydrolysis rapidly occurs under alkaline conditions

Reactivity Profile

A halogenated dicarboximide. Organic amides/imides react with azo and diazo compounds to generate toxic gases. Flammable gases are formed by the reaction of organic amides/imides with strong reducing agents. Amides are very weak bases (weaker than water). Imides are less basic yet and in fact react with strong bases to form salts. That is, they can react as acids. Mixing amides with dehydrating agents such as P2O5 or SOCl2 generates the corresponding nitrile. The combustion of these compounds generates mixed oxides of nitrogen (NOx).

Trade name

BAS-352-F?; BAS-35204-F?; CURALAN?; FLOTILLA?; FUMITE RONALIN?; MASCOT? contact turf fungicide; ORNALIN?[C]; POWERDRIVE?; RONILAN?; RONILAN-DF?; RONALINE-FL?; TOUCHE?; VINCHLOZOLINE?; VINCLOZOLINE?; VORLAND?

Safety Profile

Low toxicity by ingestion and inhalation. Mutation data reported. When heated to decomposition it emits very toxic fumes of Cland NOx.

Purification Methods

Crystallise the fungicide from Me2CO/H2O. Its solubility at 20o (w/w%) is 44 (Me2CO), 32 (CHCl3), 25 (EtOAc) and 10 (H2O). It irritates the eyes and skin. [GP 2,207,576 1973, Chem Abstr 79 137120 1973.]

Degradation

Vinclozolin (1) was rapidly hydrolysed in alkaline solution. The hydrolytic DT50, values in pH 5, 7 and 9 solution at 25 °C were 45 days, 13.4 hours and 1.6 hours, respectively (Melkebeke et al., 1986). Szeto et al. (1989a) and Villedieu et al. (1994, 1995) reported that the opening of the oxazolidinedione ring by attack of the hydroxyl ion on the two carbonyl groups is the primary hydrolysis mechanism to yield 2-{[3,5- dichlorophenyl)carbamoyl]-oxy}-2-methyl-3-butenoica cid (2) and 3'5'- dichloro-2-hydroxy-2-methylbut-3-enanilide(3) as major products. The formation of compound 3 was likely via the intermediate N-(2-hydroxy- 2-methyl-1-oxo-buten-3-yl)-3,5-dichlorophenyl-1-carbamic acid (4). 3,5- Dichloroaniline (5) was reported as a minor hydrolysis product. The proposed hydrolytic degradation pathway of vinclozolin is presented in Scheme 1. Compound 3 was also reported as the primary degradation product of vinclozolin in wine (pH 3-4, 30 °C) whereas 3,5- dichloroaniline (5) was not detected in the wine samples (Cabras et al., 1984; Pirisi et al., 1986). The degradation rate of vinclozolin in aqueous solution at λ> 290 nm was slower than at λ>230 nm; furthermore, the addition of humic and fulvic acids catalysed the aqueous photodegradation reaction (DT50 8 hours) to yield compound 5 and 3,5-dichlorophenyl isocyanate (6) as primary degradation products (see Scheme 1; Hustert and Moza, 1997). Schwack et al. (1995) reported the photolytic reactions of vinclozolin in various organic solvents. Addition of the solvent molecules to the vinyl moiety and dechlorination products were observed as major photodegradation reactions.

General Description

Vinclozolin is a fungicide that undergoes rapid photodegradation under UV light (254 nm), with half-lives of 1.01 minutes in water and 2.0 minutes in methanol-water solutions. Its photolysis primarily involves the cleavage of the 2,4-oxazolidine-dione ring, yielding 3,5-dichlorophenyl isocyanate and 3,5-dichloroaniline as major degradation products, along with dechlorination and the loss of the vinyl group (-CH=CH2). This indicates its instability in aquatic environments under UV exposure.

Agricultural Uses

Fungicide: Vinclozolin is a non-systemic fungicide which has been used on vines (such as grapes), strawberries, raspberries, chicory grown for Belgian endive, lettuce, kiwi, canola, succulent beans, and dry bulb onions. Import tolerances have been established to permit. Not approved for use in EU countries . Registered for use in the U.S.