Preparation and Performance of Overbased Complex Sulphonates

Overbased complex sulphonates containing two metals - sodium and magnesium - were prepared by using overbased magnesium sulphonate as the starting material. Borated overbased complex sulphonate containing two metals was synthesized by reaction of boric acid with the corresponding sulphonate. The total base number (TBN) of overbased complex sulphonates decreased compared with that of magnesium sulphonate, while TBN of borated overbased complex sulphonate further decreased. The detergency, anti-oxidation and extreme pressure performances of overbased complex sulphonates were improved compared with those of overbased magnesium sulphonate; the anti-oxidation and extreme pressure performances of borated overbased complex sulphonates were further improved whereas its detergency was reduced.