Published March 2011
New antioxidants of synthetic oils
C.F.OsmanovaThe compounds impact of a number of 3.4-dihydro-3-(aryl)-6-acetyl-2H-1.3-benzoxazines on thermo-oxidative stability of synthetic oil-pentaerythrito-ester of fatty acids C5-9 (PEE) has been studied. The studied compounds were inserted into oil in concentration 0.51%. The samples of oils were oxidized on modified unit VTI (MRTU 8-1-157-65) at temperature 225 оC during 10 and 25 hours in the presence of aluminum, copper and steel plates during continuous flow of dry air with the speed rate 10 ml/min on 10 g of oil. The degree of oils oxidation with the samples of compounds has been evaluated by the change of acid number viscous properties and appearance of signs of corrosion of metallic plates. It was shown that antioxidative properties of investigated compounds depend on the nature of substituents in orto-position to oxazine cycle. So, it has been defined that halogens in comparison with alkyl- and alkoxy-groups strengthen the thermooxidative properties of 3.4-dihydro-1.3-benzoxazines. It was shown that the substitution of acetyl group on benzoyl in molecule of corresponding oxazine leads to decrease its antioxidative properties. It was revealed that in the line of 3.4-dihydro-1.3-benzoxazines the more efficiency shows 3.4-dihydro-3-(p-anisyl)-6-acetyl-8-chlor-2H-1.3-benzoxazine. So, the last in 1% concentration during 25 hours at 225 оC temperature decreases the acid content of oil from 8.5-10.58 mg KOH/q till 3.97 mg KOH/q, there is no corrosion of metallic plates, viscosity of oil is on the etalon level. Thus, the results of tests have shown, that 3.4-dihydro-1.3-benzoxazines are effective antioxidants of synthetic oils with anticorrosive properties and can provide work of mechanisms in conditions of high temperatures.
