Polyalkylene Glycol Acid Additives

Preparation of Methoxy-Polyethylene Glycol Valeric Ethyl Ester 

A reactor was charged with polyethylene glycol (0.5 mol M 10,000), and treated with 50 ml of toluene, and azeotropically dried by refluxing for 2 hours. The resulting mixture was dissolved in 30 ml of THF and treated dropwise with sodium hydride (5 mmol) dissolved in 20 ml of THF and refluxed overnight. This mixture was then treated with ethyl-5-bromovalerate (5 mmol) and refluxed overnight and concentrated. The residue was precipitated by the addition of 2-propanol/diethyl ether, 1 1, and then fdtered to yield 4.5 g of isolated product. 

The Step 1 product (4 g) was dissolved in 100 ml of 1 M NaOH and stirred at ambient temperature overnight. The pH of the mixture was adjusted to 2.5 using 6M hydrochloric acid the mixture extracted using 50 ml, 40 ml, and 30 ml of CH2CI2, dried with Na2S04, and concentrated. The concentrate was precipitated in diethyl ether, and 3 g of product were isolated. 

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P.S. Ballon, C.-Y. Won, Polyalkylene glycol acid additives. U. S. Patent 7193031, assigned to Hoffman-La Roche Inc., March 20,2007. 

In a fully synthetic oil, there is almost certainly some mineral oil present. The chemical components used to manufacture the additive package and the viscosity index improver (VI) contain mineral oil. When all these aspects are considered, it is possible for a "fully synthetic" engine oil to surpass mineral oil (Shubkin, 1993). Synthetic oils fall into general ASTM classification (a) synthetic hydrocarbons (poly-a-olefins, alkylated aromatics, cycloaliphatics) (b) organic esters (dibasic acid esters, polyol esters, polyesters) (c) other fluids (polyalkylene glycols, phosphate esters, silicates, silicones, polyphenyl esters, fluorocarbons). 

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