Abstract: The oligomerization of 1-dodecene for preparation of low and medium viscosity PAO was studied using aluminum chloride-lauric complex as a catalyst. The preparation cost of low and medium PAO by oligomerization at high temperature was also analyzed based on the cationic mechanism. The effect of mole ratio of lauric acid/AlCl3, reaction temperature and time as well as hydrogen chloride removal after modification of AlCl3 with lauric acid on PAO and dimer yields was examined. The results indicate that the best preparation conditions for PAO synthesis are: AlCl3 of 3%, lauric acid/AlCl3=0.9, reaction temperature 50 ℃, reaction time 3 h. Under the optimal conditions, the yield of PAO is 85% with viscosity 19.56 mm2/s (100 ℃)，viscosity index 161 and pour point -48℃. When the hydrogen chloride is removed after modification of alumina with lauric acid, the dimer yield is 3.4%. The obtained product is a low and medium viscosity PAO with a narrow molecular distribution and a better evaporation performance.

Key words: low and medium viscosity PAO, AlCl3, lauric acid, carbocation, dimer