Abstract: 5 types of alkyl benzene sulfonic acids (A,B,C,D,E) were used to synthesize overbased calcium sulfonates which were further to be used to prepare sulfonate grease. Test results indicated that sulfonate grease samples prepared by calcium sulfonates Ca-C and Ca-D (from sulfonic acids C and D, respectively) exhibited better performance as compared with the others. Orthogonal experiments were designed to investigate the influence of promoter amount, co-promoter, water and carbon dioxide on the properties of sulfonate, and to obtain the optimum preparation conditions. Based on these results, overbased calcium sulfonates Ca-C and Ca-D were prepared in 50 L pilot plant reactor, the TBN of prepared Ca-C and Ca-D was 396.1 mgKOH/g and 391.6 mgKOH/g, respectively; their 100 ℃ kinetic viscosities were 134.28 mm2/s and 92.27 mm2/s, respectively, and both having amorphous carbonate. Finally, two sulfonate grease products were prepared by calcium sulfonates Ca-C and Ca-D in pilot plant scale, it was observed that the conversion of calcium sulfonates Ca-C/Ca-D to synthetic grease could be completed in short time. The qualities of these two products met the requirements of relative product specifications, and they exhibited good performance at high temperature, as well as resistant to water.

Key words: complex sulfonate grease, overbased calcium sulfonate , process condition, optimization