Use of oils comprising non-neurotoxic anti-wear additives

A method for lubricating aircraft or aeroderivative turbines for reducing the neurotoxicity of an oil comprising:

• providing the oil that is free of tricresyl phosphate, the oil comprising as an anti-wear additive at least one polyphosphorus compound of the formula (I):
• wherein each of R1, R2, R3 and R4 is independently an alkyl or aryl group or an O-alkyl or O-aryl group, A is an alkyl, aryl or aralkyl group, each of X1 and X2 is independently a single bond, an oxygen atom or a nitrogen atom, with the provision that when A is a monocyclic aryl group selected from phenyl, thiophene or pyridine, X1 and X2 are diametrically opposed in order to maximize the distance between X1 and X2, and n is an integer ranging between 1 and 5, wherein the additive is from 0.1 to 10 weight % based on the total weight of the oil;
• and
• applying an effective amount of the oil to the aircraft or aeroderivative turbine,
• wherein the concentration values of the at least one polyphosphorus compound required to inhibit 50% of the activity of human erythrocyte acetylcholinesterase (hAChE) and equine serum butyrylcholinesterase (eqBuChE) are both ≥15 mg/L, assessed using a spectrometric method, and
• wherein the neurotoxicity and reprotoxicity degrees of the at least one polyphosphorus compound assessed by Quantitative Structure-Activity Relationship (QSAR) modelling applying a Generalized Linear Model (GLM), is ≤0.2% for neurotoxicity and ≤3% for reprotoxicity.