Lubricant base fluids based on renewable raw materials - Their catalytic manufacture and modification

Lubricants based on renewable raw materials and their derivatives are drawing increased attraction in various applications. Here, the environmental awareness is the key factor of success. The use of such rapidly biodegradable materials is especially favourable in loss-lubrication and hydraulic systems with increased risk of damage. Environmentally friendly, biodegradable alternatives are available for a large variety of mineral oil based lubricants. The substitution of mineral oil with biodegradable base oils is a primary objective. Vegetable oils are the major source of these base fluids. Compared to conventional mineral oil based fluids most of such substances exhibit lower thermal and oxidation stability and even worse low-temperature behaviour. These physical and chemical properties can be improved by chemical modification. This review covers chemical reactions performed on fatty compounds on both laboratory and industrial scale. Economic processes are presented as well as new reactions with potential market value. Alternative routes to improved rapidly biodegradable base fluids are mentioned too, e.g. breeding successes with high oleic sunflower oil. (C) 2001 Elsevier Science B.V. All rights reserved.