Corrosion control at refineries remains a challenge because the mechanism of naphthenic acid (NAP) corrosion is still not fully understood. The rate of NAP corrosion does not correlate with acidity (as measured by total acid number); therefore, it has been suggested that a subset of NAP in petroleum fractions may be more corrosive than others. Because the primary corrosion product (iron naphthenates) may thermally decompose to ketones at corrosion temperatures (250–400 °C), ketones in corrosion fluids could potentially be used to implicate specific problematic acids in corrosion tests. To that end, we have developed a method for isolating and characterizing ketones in corrosion test solutions. Ketones from tests on palmitic and 4-cyclohexyl pentanoic acids (C₁₆H₃₂O₂ and C₁₁H₂₀O₂) have been successfully isolated with a strong anion exchange solid-phase separation. Gas chromatography/mass spectrometry identifies ketones formed as a result of model acid corrosion. Fourier transform ion cyclotron resonance mass spectrometry further confirms the detection of these ketones and structurally confirms ketones by use of a commercially available reagent that targets ketones and aldehydes. Additional oxygen species generated in the corrosion test likely result from reactions between dissolved atmospheric oxygen and the mineral oil matrix. With this method now validated, it can be applied in future studies of more complex acid mixtures to determine any structural specificity in naphthenic acid corrosion.

中文翻译：

---

高温环烷酸腐蚀形成的酮的分离和检测方法

炼油厂的腐蚀控制仍然是一个挑战，因为环烷酸（NAP）腐蚀的机理仍不完全清楚。NAP腐蚀的速率与酸度（以总酸值衡量）无关。因此，有人提出，石油馏分中的NAP子集可能比其他的更具腐蚀性。由于主要的腐蚀产物（环烷酸铁）在腐蚀温度（250–400°C）下可能热分解为酮，因此腐蚀液中的酮可能会被用于暗示腐蚀试验中特定的有问题的酸。为此，我们开发了一种用于分离和表征腐蚀测试溶液中酮的方法。棕榈酸和4-环己基戊酸（C ₁₆ H ₃₂ O ₂和C ₁₁ H ₂₀ O ₂）已通过强阴离子交换固相分离成功分离。气相色谱/质谱法鉴定出由于模型酸腐蚀而形成的酮。傅里叶变换离子回旋共振质谱进一步证实了这些酮的检测，并通过使用靶向酮和醛的可商购试剂结构上证实了酮。腐蚀试验中产生的其他氧气可能是由溶解的大气氧气与矿物油基体之间的反应引起的。现在验证了该方法，可以将其用于更复杂的酸混合物的未来研究中，以确定环烷酸腐蚀中的任何结构特异性。