Diester lubricant

Natural fatty aeid-based lubricants fall between mineral oil and the synthetic acid diester lubricants in both performance and price (Figure 6.8) as such they find niche applications. Compared to mineral oils vegetable oil-based lubricants offer several advantages, notably ... 

Devine, M.J., Lamson, E.R. and Stallings, L., Molybdenum Disulfide Diester Lubricating Greases, NLGI Spokesman, 27, 320, (1964). 

TM for acrylic polymers supplied in special oil solution or in diester lubricant. 

Use Gaskets and rubber parts for contact with oils and diester lubricants. 

The two polymers have similar properties with the latter (XI) having better low temperature properties. In general, the polymers are inferior to the vinylidene fluoride copolymers described previously. However, they do show superior resistance to synthetic diester lubricants used in jet engines and this accounts for their continued use. 

The most common liquid lubricants are mineral oils (usually naphthenic), esters (either diesters or complex esters), polyalpha olefins and polyalkylene glycols. 

Lubricants, Fuels, and Petroleum. The adipate and azelate diesters of through alcohols, as weU as those of tridecyl alcohol, are used as synthetic lubricants, hydrauHc fluids, and brake fluids. Phosphate esters are utilized as industrial and aviation functional fluids and to a smaH extent as additives in other lubricants. A number of alcohols, particularly the Cg materials, are employed to produce zinc dialkyldithiophosphates as lubricant antiwear additives. A smaH amount is used to make viscosity index improvers for lubricating oils. 2-Ethylhexyl nitrate [24247-96-7] serves as a cetane improver for diesel fuels and hexanol is used as an additive to fuel oil or other fuels (57). Various enhanced oil recovery processes utilize formulations containing hexanol or heptanol to displace oil from underground reservoirs (58) the alcohols and derivatives are also used as defoamers in oil production. 

Diesters. Many of the diester derivatives are commercially important. The diesters are important plasticizers, polymer intermediates, and synthetic lubricants. The diesters of azelaic and sebacic acids are useflil as monomeric plasticizing agents these perform weU at low temperatures and are less water-soluble and less volatile than are diesters of adipic acid. Azelate diesters, eg, di- -hexyl, di(2-ethylhexyl), and dibutyl, are useflil plasticizing agents for poly(vinyl chloride), synthetic mbbers, nitroceUulose, and other derivatized ceUuloses (104). The di-hexyl azelates and dibutyl sebacate are sanctioned by the U.S. Food and Dmg Administration for use in poly(vinyl chloride) films and in other plastics with direct contact to food. The di(2-ethylhexyl) and dibenzyl sebacates are also valuable plasticizers. Monomeric plasticizers have also been prepared from other diacids, notably dodecanedioic, brassyflc, and 8-eth5lhexadecanedioic (88), but these have not enjoyed the commercialization of the sebacic and azelaic diesters. 

Synthetic lubricants (diester) Hydraulic fluids Fair to good Excellent Poor to fair Poor Fair to good... 

Esters for lubricant applications are divided into five groups monocarboxylic acid esters (monoesters), dicarboxylic acid esters (diesters), glycerol esters, polyol esters, and complex esters. 

The plasticizer-range alcohols are largely used as feedstock for production of high molecular weight diesters of phthalic, adipic, azelaic, and sulftiric acids. All these are used primarily in plasticizers for polyvinyl chloride (PVC) and other plastics. The plastics industry also uses them as additives for heat stabilization, to control the viscosity of PVC plastisols, ultraviolet absorbers, flame retardants, and antioxidants. They are also found in synthetic, lubricants, agricultural chemicals, and defoamers. 

Three simulated service liquids are given in ISO 1817 and ASTM D471 to simulate a diester type lubricating oil, and two hydraulic oils, but ASTM D471 also standardises a further three liquids. 

Poly(a-olefins) or PAOs, polyol esters and diesters are now used in automotive and marine engine oils. To understand how an ester lubricates, it is important to consider its behavior in the different lubrication regimes, especially boundary lubrication when the properties of the bulk lubricant (e.g. viscosity) are of minor importance. The chemical properties of the lubricant responses under extreme conditions will become increasingly important. The polar ester will preferentially stick to the surface of metal when a small amount of ester is added to a low viscosity nonpolar fluid (PAO), (Randles, 1999 Spikes, 1999). When the two metal surfaces come closer together, the polar ester molecules stay in the contact zone. The use of fully synthetic engine oil formulations has produced some improvement in viscosity control and engine cleanliness in the piston and valve train areas over petroleum-based oils (Boehringer, 1975 Frame et ah, 1989 Kennedy, 1995 Lohuis and Harlow, 1985). 

Thermal, oxidative and hydrolytic stability. Organic esters and PAO inhibited lubricant base stocks resist oxidative and thermal degradation better than petroleum-based oil petroleum (121 °C), PAO (121-177°C), diesters (149-177°C), and polyol esters (177-218°C). 

The application of branched-chain alcohol diesters in part-synthetic lubricants is covered as one of the ways the petroleum industry is responding to the challenges brought on by the trend toward new smaller cars with more demanding lubricant requirements. 

Diester synthetic base stock lubricants formulated with 2-ethylhexanol (e.g., di-2-ethylhexyl adipate) provide excellent low temperature starting properties in automotive crank case applications and are also employed as lubricants for industrial machinery such as compressors and turbines. 

The ideal diester for use in a partial synthetic lubricant, i.e. blend of diester, petroleum basestock and additives, should have the lowest viscosity at both high and low temperatures, and also be the least volatile. Of course, it would also need to be resistant to oxidation and corrosion and provide lubrication and wear protection when compounded into a finished lubricant. The low viscosity requirement of the synthetic portion of the partial synthetic lubricant is for economic reasons. The synthetic portion is substantially more expensive than the petroleum portion and the lower the amount required to achieve the low viscosity of the final oil, the better the final economics. As mentioned earlier, the low volatility is desirable to prevent carrying the... 

As can be seen, this partial synthetic passenger car crankcase lubricant based upon the 2-ethylhexanol diester of azelaic acid very successfully passed the engine tests required to qualify as an SF grade engine oil. All of these tests were successful on the first try. It is not unusual for multiple runs to be made before a pass is obtained. 

Diesters prepared from specific monohydric alcohols can be formulated into low viscosity partial synthetic automotive crankcase lubricants. These diester basestocks exhibit definite advantages over petroleum basestocks of similar and sometimes higher viscosities. These advantages are ... 

Esters such as di(2-ethylhexyl) adipate and an oligomeric ester of neopentyl glycol find application as lubricants, and it is suggested that they can be used as environmentally friendly substitutes for petroleum-derived lubricants. They have been synthesized recently by alcoholysis of dimethyl adipate ester and the corresponding alcohols, with alkaline earth metal compounds as the catalysts.[75] MgO does not show any activity for either transesterification reaction, whereas CaO gives yields of both diesters near 100 % after 4h in a batch reactor. 

Phosphate esters are widely used in metalworking and lubricants. A C12 h with 6 mol of ethylene oxide (diester) can be used as an emulsifier but also as an extreme pressure additive - it can reduce wear where there is high pressure metal to metal contact. PEs can also show corrosion inhibiting properties, as with petroleum sulphonates and the emulsifying power of PEs with low foam is used in agrochemical formulations. PEs can act as dispersants or hydrotropes in plant protection formulations, allowing the development of easy-to-handle and dilute formulations of both poorly miscible and insoluble herbicides. 

Typical lubricants are fatty alcohols C]2-C22, fatty acids C14-Ci8, their esters with fatty alcohols, glycerol or pentaerythritol, amides (2) or diamides (3) and metallic soaps (see Heat stabilizers ), acids C28-C31 from montan wax and their esters, diesters of phthalic acid (4b), paraffin wax C2o-C70, PE waxes Ci25-C70o or their oxidized (polar) grades containing hydroxyl and carbonyl groups. 

E.P. (ethylene propylene) Water, dilute acids and alkalies, ketones, alcohols, phosphate ester base fluids, and silicone oils Petroleum oils or diester base lubricants Typical color purple. Temperature range -54 to 149°C. Easily compressed. Density 0.86. 0.85... 

Monoalkyl phosphate and phosphate esters are special types of phosphoms-contain-ing anionic surfactants that are of great industrial importance. They are used for flameproofing, as antistatic for textiles, for foam inhibition, as an extreme pressure (EP) lubricant additive, as a surfactant component for alkaline, and as acid cleaners and for special cosmetic preparations (5). The commercially available phosphate ester products are complex mixtures of monoester and diester, free phosphoric acid, and free nonionic. 

Alkyl phosphates, also coco based, are formed by the reaction of fatty alcohol with phosphorous pentoxide. The product is a mixture of monoesters and diesters. Its sodium salt (MAP) is reportedly mild and is used in facial wash, such as Kao s Biore. Other uses are as antistatics in textile auxiliaries, corrosion inhibitors, surfactant additives for extreme pressure (EP) lubricants, and surfactant components in alkali and acid cleaners. Coco-based alkyl polyglycosides (APG) have been successfully produced and marketed by Henkel in the United States. The alkyl polyglycoside fuUy satisfies the demand for a mild surfactant and is completely biodegradable. 

Dithiophosphoric-0,0-diester with long alkoxy-groups (> 5), optionally with aryloxy-groups, are neutralized in large quantities with zinc oxide to oil-soluble zinc salts and utilized in this form as lubricating oil additives. The zinc dialkyldithiophosphates form a protective layer on metallic materials, which reduces the wear and corrosion of these materials and protects the lubricating oil from oxidation. 96 10 t of zinc dialkyldithiophosphate and other lubricating oil additives on the basis of diphosphorus(V) sulfide were utilized in the USA in 1994. 

Plexor [Rohm Haas], TM for synthetic lubricants and additives for petroleum oils. Most grades are diesters of dibasic acids some are polyesters or polyether alcohols. The ester lubricants have very low freezing points, high flash points, little change of viscosity with temperature. 

The largest volume of grease in use is made from petroleum products produced from naphthenic, paraffinic, blended, hydrocracked, hydrogenated, and solvent-refined stocks. In addition to petroleum oils, other lubricating fluids, such as esters, diesters, silicones, polyethers, and synthetic hydrocarbons, are also used. Of the synthetic fluids used in grease manufacture, the most common type is poly(alpha)olefin (PAO). 

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