Wonjin Institute for Occupational and Environmental Health, Seoul, Korea.
Saf Health Work. 2010 Dec;1(2):175-82. doi: 10.5491/SHAW.2010.1.2.175. Epub 2010 Dec 30.
This study examined how ethanolamines (EAs) with the same functional alcohol group (HOCH(2)CH(2)), such as mono-EA (MEA), di-EA (DEA), and tri-EA (TEA), in water-based metalworking fluids (wbMWFs) are vaporized, condensed, and transformed by heat generated during metalworking.
Two types of experimental apparatus were manufactured to achieve these objectives.
Vaporization tests using a water bath showed that the vaporization rate increased markedly from 0.19 mg/m(2)·min at 23.5℃ to 8.04 mg/m(2)·min at 60℃. Chamber tests with a heat bulb revealed that "spiked" MEA was fully recovered, while only 13.32% of DEA and no TEA were recovered. Interestingly, non-spiked types of EAs were detected, indicating that heat could convert EAs with more alcohol groups (TEA or DEA) into other EAs with fewer group(s) (DEA or MEA). The EA composition in fresh fluid was 4% DEA, 66% TEA, and 30% MEA, and in used fluids (n = 5) was 12.4% DEA, 68% TEA, and 23% MEA. Conversion from TEA into DEA may therefore contribute to the DEA increment. Airborne TEA was not detected in 13 samples taken from the central coolant system and near a conveyor belt where no machining work was performed. The DEA concentration was 0.45 mg/m(3) in the only two samples from those locations. In contrast, airborne MEA was found in all samples (n = 53) regardless of the operation type.
MEAs easily evaporated even when MWFs were applied, cleaned, refilled, and when they were in fluid storage tanks without any metalworking being performed. The conversion of TEA to DEA and MEA was found in the machining operations.
本研究考察了具有相同功能醇基团（HOCH(2)CH(2)）的乙醇胺（EAs），如单乙醇胺（MEA）、二乙醇胺（DEA）和三乙醇胺（TEA），在水基金属加工液（wbMWFs）中是如何蒸发、冷凝和转化的。
制造了两种实验设备来实现这些目标。
使用水浴进行的蒸发测试表明，在 23.5℃时，蒸发速率从 0.19mg/m(2)·min 显著增加到 60℃时的 8.04mg/m(2)·min。带有热球的腔室测试表明，“加标”MEA 完全回收，而只有 13.32%的 DEA 和没有 TEA 被回收。有趣的是，检测到了非加标类型的 EAs，这表明热量可以将具有更多醇基团（TEA 或 DEA）的 EAs 转化为具有较少醇基团（DEA 或 MEA）的其他 EAs。新鲜流体中的 EA 组成分别为 4%DEA、66%TEA 和 30%MEA，而在使用的流体（n=5）中分别为 12.4%DEA、68%TEA 和 23%MEA。因此，TEA 转化为 DEA 可能导致 DEA 增加。在未进行加工的中央冷却系统和输送带附近的 13 个样品中均未检测到空气中的 TEA。仅在来自这些位置的两个样品中检测到 0.45mg/m(3)的 DEA 浓度。相比之下，无论操作类型如何，在所有 53 个样品中均发现了空气中的 MEA。
MEA 即使在 MWFs 被应用、清洗、再填充以及在没有进行任何金属加工的流体储存罐中时也很容易蒸发。在加工操作中发现了 TEA 向 DEA 和 MEA 的转化。
