Dicarboxylic acid esters as components of modern synthetic oils

Abstract

Purpose -The paper presents the results of research carried out on esters of carbonic, adipic, and sebacic acids with respect to their use as components of fully synthetic lubricating oil produced from a polyalphaolefin base. Straight dicarboxylic acid esters were synthesized in a transesterification reaction of dimethyl carbonate, dimethyl adipate, and dimethyl sebacate with 2-ethylhexanol and 3,5,5-trimethylhexanol. Design/methodology/approach -Oligomeric esters of adipic acid and sebacic acid were synthesized using neopentyl glycol, appropriate dimethyl adipate or dimethyl sebacate and 2-ethylhexanol as the starting material. The basic physicochemical properties of esters were determined and their compatibility with synthetic oils were defined. They were also evaluated with respect to resistance under the influence of thermo-oxidative factors, evaporation and susceptibility to hydrolytic decomposition. The selected esters were complemented with commercial additives to make up a fully synthetic lubricating oil with a polialphaolefin base. A special attention was paid to the effect of ester compounds on the physicochemical properties of the formulated oil. Findings -The obtained results show that straight adipates and sebacates of 2-ethylhexanol and 3,5,5-trimethylhexanol as well as oligomeric esters in which molecules are terminated with 2-ethylhexyl group can be used as component of lubricating oils. The addition of these esters reduced the pour point by a few degrees in comparison with the tested base oil. The temperature fell below 408C. The presence of esters significantly improved the viscosity index. A positive influence of esters on the lubricating properties of the formulated oil was also observed. On the contrary, dialkyl carbonates show too low boiling point, which is indicated by the high amount of volatile components, 19-22 percent, in final product. Adipic and sebacic oligomers containing methoxyl groups in their structures proved to be immiscible with polyalphaolefins. Originality/value -The achievement of this work is the synthesis of new oligomeric esters of dicarboxylic acids, which can be excellent additives for improving properties of synthetic oils. Further studies will be focused on the use of esters as components of engine oils. This requires real motor tests.

Synthesis and physical properties of novel estolides from dicarboxylic acids and methyl ricinoleate

“…The behavior of the tested esters within each group can be linked with the chemical structures of respective compounds. Therefore, esters of sebacic acid were more stable than those of suberic and adipic acid esters [29]. All the isobutyl esters exhibited inferior onset temperature values compared to n-butyl esters.…”

Optimization for esterification of saturated palm fatty acid distillate by D-optimal design response surface methodology for biolubricant production

“…However, in extreme service conditions (i.e., very high or low temperatures, vacuum, radiation, extreme contact pressure, etc. ), biodegradable liquid esters or solid lubricants are selected [1].…”

“…The final products of the synthesized SFA PFAD esters were characterized and analyzed using FTIR,1 H,13 C NMR, and high temperature column GC-FID. The chemical structure of optimized synthesized SFA PFAD esters after RSM was verified using FTIR and NMR ( 1 H and 13 C) spectroscopy.…”

Effect of Alcohol Structure on the Optimum Condition for Novozym 435-Catalyzed Synthesis of Adipate Esters

“…They have been most commonly applied in manufacturing of lubricating oils, solvents, plasticizers, paints, food, pharmaceuticals, cosmetics, and liquid fuels [ 1 ]. Among the esters, dicarboxylic acid esters are of particular interest due to their excellent properties such as low volatility, high flash point, good thermal stability, and low toxicity [ 2 ]. Up to now, the processes of esterification in industry are still catalyzed by chemical catalysts mainly sulfuric acid.…”