A Method for Determining the Volatility of Herbicides

Abstract

The effect of time, flow rate, and temperature on the volatilization of technical grade n-butyl ester of 2,4-D [(2,4-dichlorophenoxy)acetic acid] in a closed air-flow system was evaluated. The amount of ester volatilized was linear with time, at constant temperature and air flow. Volatility increased approximately 8-fold when the temperature was increased from 30 C to 50 C. At 30 C, volatility increased with each doubling of air flow rate from 0.86 nmole/cm2 per hr at 14 L/hr to 1.62 nmole/cm2 per hr at 57.6 L/hr. The effects of temperature, flow rate, and the relationship between vapor pressure and rate of volatilization were also analyzed. The system provided a simple and quantitative method for determining the relative volatilities of both technical and formulated herbicides.