Adam Frédérick, Bertoncini Fabrice, Thiébaut Didier, Esnault Sébastien, Espinat Didier, Hennion M C
Institut Français du Pétrole, Département Physique et Analyse, BP3, 69390 Vernaison, France.
J Chromatogr Sci. 2007 Nov-Dec;45(10):643-9. doi: 10.1093/chromsci/45.10.643.
The detailed characterization of middle distillates is essential for a better understanding of reactions involved in refining processes. Owing to a higher resolution power and an enhanced sensitivity, but especially to a group-type ordering in the chromatographic plane, comprehensive two-dimensional gas chromatography (GCxGC) offers unsurpassed characterization possibilities for petroleum samples. However, GCxGC fails to totally discriminate naphthenes from unsaturates occurring in hydrotreated diesel samples. This article aims at promoting the implementation of LC-GCxGC for the quantitative determination of hydrocarbon distribution in middle distillates, including naphthenes. In this configuration, liquid chromatography (LC) enables the separation of hydrocarbons into two fractions (viz., saturated and unsaturated) before the subsequent analysis of each fraction by GCxGC. In this paper, the choice of GCxGC conditions in order to achieve the separation and identification of hydrocarbons by chemical class is discussed; under these conditions, naphthenes are separated according to the number of saturated rings. For the first time, the presence of di-, tri-, and tetra-naphthenes resulting from the hydroconversion of aromatics can clearly be evidenced. A quantitative procedure for the determination of the distribution of hydrocarbons, including the distribution of naphthenes according to the number of saturated rings, is also proposed and discussed in detail. LC-GCxGC is found to provide an unequalled degree of information that will widely contribute to a better understanding of hydroconversion processes.
对中间馏分进行详细表征对于更好地理解炼油过程中涉及的反应至关重要。由于具有更高的分辨率和增强的灵敏度，特别是由于色谱平面中的族类型排序，全二维气相色谱（GCxGC）为石油样品提供了无与伦比的表征可能性。然而，GCxGC无法完全区分加氢处理柴油样品中出现的环烷烃和不饱和烃。本文旨在推动液相色谱-全二维气相色谱（LC-GCxGC）的应用，用于定量测定中间馏分中的烃类分布，包括环烷烃。在这种配置下，液相色谱（LC）能够将烃类分离成两个馏分（即饱和馏分和不饱和馏分），然后通过GCxGC对每个馏分进行后续分析。本文讨论了为实现按化学类别分离和鉴定烃类而选择的GCxGC条件；在这些条件下，环烷烃根据饱和环的数量进行分离。首次能够清晰地证明由芳烃加氢转化产生的二环、三环和四环环烷烃的存在。还提出并详细讨论了一种用于测定烃类分布的定量方法，包括根据饱和环数量对环烷烃分布的测定。结果发现，LC-GCxGC提供了无与伦比的信息量，将极大地有助于更好地理解加氢转化过程。
