Abstract: The content of wax ,pitch and arene into vacuum cutⅡand that of vacuum cut Ⅳ from Da Gang′s Yang San Mu oil field are determined. The result shows the content of wax and pitch is comparatively low, and the content of arene is 42.4% and 38.2% respectively,so the kinds of oil could directly be sulphonated. Dilute SO3 as sulphanation dose is extracted from smoking sulphuric acid with nitrogen. Direct sulphonation rate of vacuum of it to heavy alkyl benzene is 6：4,the productivity of crude product reaches 90.3%.Influence factors of reaction are optimized with neutralization value, active thing content,unsulphonation thing content and inorganic salt as evaluation standards.The result indicates that the optimal reaction conditions are as follows: reaction temperature 50～55℃.Reaction time 5h and SO3 average concentration of 4.5g/L,current of diluted gas 140L/h.After neutralized with alkali,the petroleum sulphonate with steady performance is obtained without separation from reaction fluid.〖

Key words: gas phase method, combination, petroleum sulfonate, reaction conditions, optimization