分子组成对润滑油基础油黏度指数的影响

弄清分子组成对基础油黏度指数的影响，对原料优选和加工工艺调整有重要意义。采用传统分析与高分辨质谱、核磁共振方法相结合的方法，研究了4个样品的黏度指数与分子组成差异。结果表明，基础油B1、B2的链烷烃含量较低、环烷烃含量较高、异构化程度iP/nP值较大，其黏度指数与A1、A2相差约15个单位；尽管A1、B1的链烷烃含量较低、各环数环烷烃含量均比较高，但是从分子组成上来看分布在碳数较大的范围，所以其黏度指数分别大于A2、B2；进一步分析实沸点蒸馏所得窄馏分的性质和组成表明，窄馏分的黏度指数随终馏点的增加而增加，在相同的沸点范围内高黏度指数的窄馏分其链烷烃和一环环烷烃含量较高。

EFFECT OF MOLECULE COMPOSITIONS ON VISCOSITY INDEX OF LUBE BASE OIL

Well understanding the impact of molecule compositions on the viscosity index of lube base oil is very important for feedstocks selection and operation adjustment. With the combination of traditional and high resolution mass spectroscopy, nuclear magnetic resonance characterization methods, the relation of viscosity index and molecule compositions of four samples (feed A1 and A2, base oil product B1 and B2) was studied. The results showed that B1 and B2 have lower content of paraffin, lower iP/nP, but higher content of naphthene, resulting in lower viscosity index than A1 and A2. The content of alkanes in A1 and B1 is lower and the content of naphthene with different ring numbers is higher than in A2, B2, respectively, A1and B1 still have higher viscosity index because they have more carbon number in the same distillate range. The properties and constituents of narrow fractions indicated that the viscosity index of narrow fraction increases with the end point and the fraction with higher viscosity index has higher contents of paraffins and one ring naphthenes.