有机溶剂的特性(精)

General AcuteToxic Effects
❖ CNS depression - High level exposure - 中樞神經麻醉效果，例如乙醚麻醉 一般而言，碳鏈愈長，含雙鍵、鹵素基（氯、溴、 氟等）的溶劑中樞效果愈強。臨床上，暴露的人會 頭暈、頭痛、噁心、嘔吐、嗜睡，平衡失調，像醉 酒一般，除了影響健康外，勞工甚易發生工作意外。 工作場所中常存在多種溶劑或混合物，彼此加強作 用，危害比單一物質更大。
❖ Environmental contamination major volatile organic solvents (VOCs)
Occupational Standards: TWA
TWA
The time-weighted average is the time-weighted average concentration for a normal 8-hour workday or 40hour workweek, to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.
To illustrate the TWA formula, assume that a substance has an 8-hour time-weighted average PEL of 100 ppm. Assume that an employee is subject to the following exposure:
❖ 化學結構
一般而言，結構相似者毒性可能相近，例如鹵化有 機溶劑（四氯甲烷，三氯乙烯，四氯乙烯等），對 肝皆具毒性。也可能差很多， 2,4-diaminotoluene (liver tumor)/2,6-diaminotoluene (not)
The main determinants of a solvent’s inherent toxicity
Two hours exposure at 150 ppm Two hours exposure at 75 ppm Four hours exposure at 50 ppm.
Substituting this information in the formula, we have:
TWA = (150)(2) + (75)(2) + (50)(4) = 81.25 ppm 8
Solvents and Vapors (Volatile Organic Compounds)
有wenku.baidu.com溶劑的特性
❖ 溶解性
脂溶性（可溶解脂肪）愈強，去脂效能愈佳，對皮 膚和神經系統的傷害也愈大
❖ 可燃性
可燃性高者作燃料，不可燃者則作滅火劑。
❖ 揮發性
蒸氣壓愈高，揮發性愈強，空氣中有機溶劑的濃度 愈大，愈多經由呼吸道吸入人體。
❖ Secondary route ➢Skin ➢Ingestion (accident)
Sources of exposure
❖ Daily activity-workplace, gas station, smoking, household, etc.
❖ Solvent abuse-produce euphoria, delusions, sedation and visual and auditory hallucination
Ceiling (TLV-C)
❖ Ceiling (TLV-C) is the concentration that should not be exceeded even instantaneously.
❖ For some substances, for example irritant gases, only the TLV-ceiling may be relevant.
Since 81.25 ppm is less than 100 ppm, the 8-hour timeweighted average limit, the exposure is acceptable
Short-Term Exposure Limit (TLV-STEL)
the maximum concentration to which workers can be exposed continuously for a short period of time (15-minute) without suffering from irritation, chronic or irreversible tissue change, or narcosis of sufficient degree to increase accident proneness, impair self-rescue, or materially reduce work efficiency.
As shown in the figure, time weighted averages permit excursions above the limit provided that they are compensated by equivalent excursions below the limit during the workweek
• the number of carbon atom lipophilicity volatility
• whether it is saturated or has double or triple bonds between adjacent carbon atoms
•its configuration (straight chain, branch chain, or cyclic)
•the presence of functional groups
ex. Amides/amines-potent sensitizer
aldehyde-irritating
Route of Exposure
❖ Primary route ➢Respiratory
Related to volatility of solvent Lipid solubility MAC