Esters are created by a process called, "esterification," the reaction of alcohols or phenols with acids. For example, react tricresyl phosphate acid with an alcohol called n-butyl alcohol and the result is an ester product called "Neutra," a fuel system and crankcase cleaner.
A carboxylic acid is a general term for a number of acids with a specific molecular arrangement. A carboxylic ester can be made with one of over 120 carboxylic acids. Carboxylic acids may be used to form dibasic esters (as in NEO base oils)and polyol esters such as TMP and PE, which are used in Amsoil and Redline oils, respectively.
Hydroxyalkyl Carboxylic ester is actually a "lactone," a cyclic ester made from the salt of a hydroxy acid.
This ester is used in many motor oil formulations that contain PAO(s) and is used to increase the VI, cause a slight seal swell, adds miscibility (mixibility) for additives, increases oxidative stability, and acts as a Friction Modifier.
[ January 03, 2003, 07:54 PM: Message edited by: MolaKule ]