Abstract PROCESSES FOR PREPARING BASIC MAGNESIUM SALTS OF OIL SOLUBLE ORGANIC ACIDS BY CONTACTING AN INORGANIC ACIDIC MATERIAL WITH A MIXTURE OF THE ACIDS, OR THEIR ALKALI OR ALKALINE EARTH METAL SALTS, MAGNESIUM OXIDE, AND WATER OR ALCOHOL-WATER PROMOTER SYSTEM. CARBON DIOXIDE IS AN EXEMPLARY ACIDIC MATERIAL. LOWER ALKANOLS PARTICULARLY METHANOL, ARE USEFUL CO-PROMOTERS FOR USE WITH THE WATER. MIXTURES OF OIL-SOLUBLE SULFONIC ACIDS AND OIL-SOLUBLE CARBOXYLIC ACIDS, OR THEIR ALKALI OR ALKALINE EARTH METAL SALTS, ARE USEFUL STARTING MATERIALS FOR PREPARING BASIC MAGNESIUM SALTS. WITH ALCOHOL-WATER CO-PROMOTERS, THE INORGANIC ACIDIC MATERIAL IS CONTACTED WITH THE REACTION MIXTURE IN TWO STAGES, FIRST IN THE PRESENCE OF BOTH PROMOTERS AND THEN IN THE PRESENCE OF WATER ONLY. THE PRODUCTS ARE USEFUL AS ADDITIVES IN LUBRICANTS AND FUELS AND AS INTERMEDIATES IN PREPARING OTHER USEFUL PRODUCTS.