Some azine and azole derivatives as antioxidant additives for lithium lubricating grease

CATEGORY: LUBRICANTS
Egyptian Journal of Petroleum, Volume 22, Issue 1, June 2013, Pages 61–71
Some azine and azole derivatives as antioxidant additives for lithium lubricating grease
Reda M. Fikry a, Refaat A. El-Adly b, Nabila A. Ismail a, A.S. El-Tabei b, Hend Al-Aidy b
a Chemistry Department, Faculty of Science, Zagazig University, Egypt
b Process Design & Devolopment Department, Egyptian Petroleum Research Institute (EPRI), Egypt
Abstract
Lubricating greases experience significant deterioration under operating conditions and storage. Hydrocarbon chain is one of the major factors resulting in loss of the base fluid quality by formation of products having negative effects on the physicochemical properties.  These include, in particular, the total acid number and dynamic viscosity. Antioxidants protect the quality of lubricating grease by retarding oxidation reactions. Accordingly, researchers studied the preparation and evaluation of certain compounds which act as antioxidants for prepared lithium lubricating grease.
The additives are α-(2-amino-3-cyano-6-pyridyl)o-hydroxyl cinnamic hydrazide (compound I), ethoxymethyl enamino derivative (compound II) and 3-amino-5-hydroxyl-4 phenylazo-1H-pyrazole (compound III).
The structure of these compounds was determined using elemental analysis, nuclear magnetic resonance and infrared spectroscopy. Conversely, lithium lubricating grease was prepared and evaluated according to the National Lubricating Grease Institute (NLGI) and Egyptian Standard (ES). Researchers observed that the prepared lithium grease resists oxidation reaction in the presence of these compounds.
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