ESTIMATION OF HYDROPHILIC LIPOPHILIC BALANCE OF GASOLINE DETERGENT ADDITIVES VIA ALKOXY GROUP ASSAY BY GC-MS
Noman Al, Barbara Belmont.
California State University, Dominguez Hills, Carson, CA.
The EPA requires all gasolines to contain detergent to minimize engine valve and combustion chamber buildup because clean engines have been demonstrated to have better fuel economy. A leading gasoline brand uses a polyether amine detergent claimed by marketing and patents, as well as anecdotally by consumers and automotive mechanics, to be superior to the competition. A polyether amine has the general structure H3CR’(CH2CH2O)nNH2, where R’ is an alkyl chain. The amine head is slightly polar and basic and may serve as an anticorrosion chemical when in contact with the engine interior surfaces. The repeating alkoxy unit and the length of the alkyl chain influence the solubility of the detergent in gasoline and the deposit solubilizing capability of the detergent. Solubility and solubilizing capability of detergents are also predicted by their hydrophilic lipophilic balance (HLB) value. Therefore, the gasoline detergent with the HLB value most appropriate to the system can be predicted to perform better. This project attempts to characterize the HLB values of the leading brand of gasoline detergent and a generic unbranded gasoline detergent through quantification of the ethoxy groups, using gas chromatography-mass spectrometry of the derivatives acylated by reaction of acetyl chloride in the presence of a Lewis acid (FeCl3).