工業上，有機溶劑的混合使用已成一種趨勢，作業員工往往暴露在多成分有害蒸氣下，為了簡便此類環境中空氣之考核管制工作，本文研討各有關理論，擬訂一簡單有效的預估模式，期能更瞭解使用混合有機溶劑之作業場所空氣中各蒸氣濃度變化情形。
並以乙酸乙酯( Ethyl Ace tate )、甲基異丁酮(Methyl Isobutyl Ketone )及甲苯(Toluene)等三種溶劑配製成各種不同比例之混合溶液。置於單向開口抽氣室中，設定條件為 : 1 atm， 27 ℃，通風速度0.25m / sec，換氣速度30 m3 / min，任上述混合溶液自由揮發，每隔一時段後，以氣相層析儀測出各成分量之變化。所得實驗值與模式推演之預估值相互印證。結果頗為吻合。
經印證成立之模式，可供從事管理作業環境空氣及評估動物實驗暴露室中氣體組成時參考利用。 For simplify the method of evaluation of the vapor composition of mixed organic solvent in workshop, and to control the concentration of organic chemicals in the air of chamber. The evaporation behavior of mixed organic solvent was studied based on the thermodynamic principle. A simple method was designed to predict the composition changes during evaporation.
The model was designed as follows:
1. Calculated the composition in the gases phases, from state equation and known composition in the liquid phase.
2. Calculated equilibrium costance from the fraction in the gases phase (Yi) devided by the faction in the liquid phase (Xi).
3. Calculated relative volatility (a) from equilibrium constance divided by base equilibrium constance.
4. Find the vaporated rate of organic solvent mixtures from experiment.
5. Calculated the wt. change rate of every component of organic solvent mixtures vs. the wt. change rate of total organic solvent mixtures from Reyleigh Equation.
6. Calculated the wt. change rate of every component of organic solvent mixtures.
7. Predicted the concentration of every component of organic solvent mixtures in the air of workshop.
Organic solvent mixtures of different composition made from ethyl acetate, methyl isobutyl ketone, and toluene were prepared and their free evaporation at 1 atm and 27℃ in a single opening hood were studied and monitored by gas chromatography.
The evaporation process calculated by the theoretical model was compared with the experimented results, and was very successful.
The proposed method can thus be used in the case of environments exposed to organic solvents, to control the concentration of organic chemicals in the air and to design the ventilation of chambers or related equipments.
