A composition comprising water and a polyalkylene glycol having an allyl content of less than 20 eq/g, which composition has reduced foaming properties and preferably a biodegradability of at least 60% as determined using OECD 301F. The polyalkylene glycol can be made by forming a first intermediate comprising an oxypropylene block by reacting propylene oxide with a polyol initiator in the presence of a Double Metal Cyanide catalyst, and then reacting the first intermediate with ethylene oxide in the presence of a KOH catalyst.

Disclosed are solvency enhancer compositions, for example, as additives to lubricating oils and as formulated in lubricating oil compositions and associated methods of preparation and use thereof. The compositions and methods can dissolve at least one of oxidation products and other organic polar compounds, due to lubricant degradation, formed and suspended in oil compositions including adding an effective amount of a solvency enhancer to the oils, wherein the solvency enhancer includes Guerbet alcohols. Further described are methods for dissolving organic deposits in an oil system including adding an effective amount of a solvency enhancer to the oil system, wherein the solvency enhancer includes Guerbet alcohols. Also provided are methods for preventing sludge and varnish formation in in-service oils including adding an effective amount of a solvency enhancer to the oils, wherein the solvency enhancer includes Guerbet alcohols.

A lubricating oil composition contains a base oil (A), a zinc dithiophosphate (B), and a sarcosine compound (C), the composition having a content of the sarcosine compound (C) of more than 0.05% by mass and 0.40% by mass or less based on the entire amount of the lubricating oil composition, and satisfying requirement () or (): Requirement (): when the content of the sarcosine compound (C) is more than 0.05% by mass and less than 0.20% by mass based on the lubricating oil composition, one or more phosphorus compounds (D) selected from an acidic phosphoric acid ester (D1) and an amine salt thereof (D2) are optionally contained; Requirement (): when the content of the sarcosine compound (C) is 0.20% to 0.40% by mass based on the lubricating oil composition, the phosphorus compound (D) is contained in an amount less than 0.50% by mass based on the lubricating oil composition.