EFFECT OF TEMPERATURE ON THE EVOLUTION OF N-BUTYL ISOCYANATE FROM AQUEOUS BENLATE(R) FORMULATIONS

Rates of n-butyl isocyanate (BIC) evolution from Benlate(R) DF and WP formulations were determined at temperatures from 25 to 40-degrees-C. The aqueous Benlate(R) mixture was added to a glass bottle containing basaltic gravel, and the gas phase BIC carried to an XAD-2 cartridge by a stream of air. The trapped BIC was eluted and analyzed by gas chromatography. For older samples obtained from a grower, the average rate of BIC evolution in the first 6 h in DF increased by more than 10-fold to 25 mug/h (3.6 ppm in the head space) when the temperature was increased from 25 to 40-degrees-C. In the WP sample, the increase was 3.8-fold to 3.5 mug/h (0.5 ppm). These results demonstrate that aqueous Benlate(R) formulations produced higher levels of BIC under elevated temperatures, especially when Benlate(R) DF was used.