Worldwide, 12 million tonnes per year of lubricants are disposed of in the environment through leakages, exhausted gas, incorrect disposal, water–oil emulsions and so on. Some are resistant to biodegradation, representing an environmental threat. One solution to modify this situation is the replacement of mineral oils by biodegradable synthetic lubricants. Esters, whose chemical structures are similar to natural triglycerides, are excellent substitutes for mineral oils. Castor oil contains around 90% ricinoleic acid, and as a result, castor oil has a higher viscosity and a lower viscosity index, compared with other vegetable oils. This work was based on the production of biodegradable lubricant base fluids from castor biodiesel esters, using various chemical catalysts.
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