Polar nitrogen-containing aromatic compounds as carriers of natural diesel lubricity

Polar nitrogen-containing aromatic compounds as carriers of natural diesel lubricity

Type	Journal Article
Author	M. Matzke
Author	A. Jess
URL	http://www.sciencedirect.com/science/article/pii/S0016236114009065
Volume	140
Pages	770-777
Publication	Fuel
Date	January 15, 2015
Abstract	Hydrodesulfurization (HDS) reduces the original lubricity of diesel fuel on which fuel injection equipment (FIE) relies for proper operation and lifetime. This problem was solved by addition of lubricity additives to low and ultra-low sulfur diesel. However, there is no clear final conclusion on the role of either sulfur- or polar oxygen- and nitrogen-containing compounds. Researchers extracted polar compounds from a gas oil by an ionic liquid so that the fuel was not saturated by hydrogen as in the industrial HDS process. Stepwise extraction and measurement of sulfur and nitrogen contents as well as lubricity revealed a significant correlation between lubricity and nitrogen content. For investigation on the molecular structure of the lubricating nitrogen compound, selected model compounds with different structural features were added to an ultra-low sulfur diesel (ULSD). Results suggest that the combination of a diaromatic base structure with a polar substituent and a nitrogen heteroatom exhibits excellent lubricity improvement superior to those structures lacking one or more of these three properties.