Triglycerides, lubrication

PPG-24 butyl ether PPG-33 butyl ether PPG-40 butyl ether PPG-53 butyl ether lubricant, unsat. polyesters Aluminum stearate lubricant, vacuum pumps PerfI uoropolyether lubricant, varnishes Cl 8 acid triglyceride lubricant, veterinary PEG-35 castor oil... 

Several other cases of packaging related taints are listed in Table 7.4. These taints involved laminates, metal-paper combinations, and metal cans. Laminates need adhesives to bind the layers together, and the adhesives were contaminated with residual solvents. The paper-metal tube taint involved closing the package before the solvent used to apply a triglyceride lubricant had an opportunity to evaporate from the metal tube lid. The solvent was sealed inside the tube with the product. The final examples in Table 7.4 are tainting from metal cans. In each of these cases, the contamination came from the lacquer fining used on the inner can surface. Foods must be protected from the can and the can from the food. This necessitates the application of a polymer film on the inside of the can surface. Any residual solvent or trace contaminants in this lacquer would potentially taint the can contents. 

Natural Ethoxylated Fats, Oils, and Waxes. Castor oil (qv) is a triglyceride high in ticinoleic esters. Ethoxylation in the presence of an alkaline catalyst to a polyoxyethylene content of 60—70 wt % yields water-soluble surfactants (Table 20). Because alkaline catalysts also effect transestenfication, ethoxylated castor oil surfactants are complex mixtures with components resulting from transesterrfication and subsequent ethoxylation at the available hydroxyl groups. The ethoxylates are pale amber Hquids of specific gravity just above 1.0 at room temperature. They are hydrophilic emulsifiers, dispersants, lubricants, and solubilizers used as textile additives and finishing agents, as well as in paper (qv) and leather (qv) manufacture. 

Japan Wax. Japan wax [8001-39-6] is a fat and is derived from the berries of a small tree native to Japan and China cultivated for its wax. Japan wax is composed of triglycerides, primarily tripalmitin. Japan wax typically has a melting point of 53°C, an acid number of 18, and a saponification number of 217. Principal markets include the formulation of candles, poHshes, lubricants, and as an additive to thermoplastic resins. The product has some food-related apphcations. 

Biodiesel is a fuel derived from renewable natural resources such as soybean and rapeseed and consists of alkyl esters derived from transesterification of triglycerides with methanol. In spite of all the advantages of biodiesel, such as low emissiotts, biodegradability, non-toxicity, and lubricity, the major hurdle in penetration of biodiesel is its high cost because of the expensive food grade refined vegetable oil feedstock. 

Fatty Acid Esters and Fatty Alcohols Fatty acid esters are obtained by transesterification of triglycerides (vegetable oils) or by esterification of fatty acid with alcohol or polyols. Fatty alcohols are obtained by hydrogenation of esters on metal catalysts. Fatty acid esters and fatty alcohols are useful platform molecules to prepare surfactants, emulsifier, lubricants and polymers. 

Traditionally metal soaps have been manufactured by reactiOTi of alkali- or alkaline earth oxides or carbonates with natural fats or oils. Both compraients are mixed and at higher temperatures the triglyceride is decomposed yielding metal soap and glycerol. Under such conditions the soap is dispersed in an excess of oil or molten fat, and lubricating greases are yielded that way. 

The use of castor oil in lubricants is particularly important, both historically and currently. Castor oil is a triglyceride with a very high, 90%, content of the fatty acid, ricinoleic acid, an unusual fatty acid, containing one double bond and a hydroxyl group, as in Fig. 6.10. 

---