| Abstract: | Total vegetable oil greases are those in which both the lubricant and gellant are formed from vegetable oil. Vegetable oil may be used as a lubricant as such or, with appropriate structural modification, as an ester or alkylated ester. Total vegetable oil greases have the advantage of good biodegradability and conform to the requirements for high performance. Total vegetable‐oil based greases can be formed by mixing preformed soap and lubricant in the required proportions to form a grease with the desired properties. Alternatively, a grease can be formed from the same vegetable oil by simultaneous alcoholysis and saponification of the oil to form the lubricant and soap. The alkali used as a catalyst for the alcoholysis reaction serves as a reactant for the saponification reaction. The use of the appropriate proportion of oil, alcohol, and alkali will thus form a grease of the desired composition. A simultaneous reaction scheme to form sodium and lithium grease using castor oil has been studied. The alcoholysis reaction is separately studied for its kinetics, and the kinetics of the alcoholysis and saponification reaction are reported. Greases with 20% soap have been formed and their properties evaluated. |
