الفهرس 
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Abstract
CONCLUSIONS The initiation step in autoxidation of base lube oils is apparently dependent on the structure of their components, aromatics are easily oxidized than the paraffins. Sulphur and nitrogen compounds playa significant role in the oxidation of base lube oils .Sulphur compounds contribute to instability by catalizing the formation and decomposition of hydroperoxide .Disulphides in addition to being insoluble in many cases, apparently form intermediate free radicals that decompose to more reactive sulphur derivat ivee The basic nitrogen constituents of lube oils are
stable species and would not be expected to oxidize readily while the non-basic nitrogen constituents are highly susceptible to autoxidation Copper seems to be more active in oxidation of oils than the other metals due to its high solubility in
the oil if compared with other metals .It was recognized that the action of metal in solution.as salts, could be quite different from that of the
bulk or massive metals. The ions of the soluble metals
react directly with oxidation products forming soaps.
But metallic surface exist only in BO far as the metal
ions go into oil medium forming metal oxide and further
initiate the rate of reactions.
Metals should be more active as an initiation in
polar media. It is found that in presence of basic
nitrogen form an oxygen complex which is reversible and
is an excellent oxidation catalyst.
In the later stage of oxidation oil with a cobalt
and iron ions have a higher deterioration effect than
oil with the same concentration of copper ions. This is
mainly due to the fact that their ions have a higher
equivalent numbers than copper ion. Moreover, simple
organic compounds which ere formed vdth oxidation products
and copper ions are more dissociatable than those formed
with cobalt and iron.
Base lube oil No. J is liable to be oxidized more
easlythan the other two oils due to its chemical
.composition which is characterized by a high percent of
aromatics and sulphur bearing compounds