الفهرس 
EXPERIMENTALOnly 14 pages are availabe for public view
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Abstract
Mineral lubricating engine oils are used in presence of air whereby oxidative chemical reactions took place which affects the deterioration of them. So additives are necessary to enhance aspects of base oils performance.
The role of lubricating oil additives is to reduce oxidation i.e. thermal degradation of the base oil, to decrease the deposition of harmful deposits on lubricated parts. Also, they minimized rust and corrosion, control frictional properties, reduce wear, and prevent destructive metal to metal contact.
This work emphasized on studying the efficiency of some prepared heterocyclic compounds (antioxidants) and poly aromatic amine (viscosity index improver and pour point depressant) on the hydro finished base stock oil (HBS) sample delivered from Co-operative Petroleum Company.
This thesis is divided into four parts:-
1- The first part is studying the physicochemical characteristics of the delivered base oil. This is carried out according to ASTM and UOP standard test methods (density, viscosity, pour point, total acid number, flash point, ash content and wax content). The oxidation test method was carried according to the standard test method ASTM D-943. The
procedure took place at a fixed temperature (120 oC) and at oxidation time intervals (24, 48, 72 and 96 hours).
2- In the second part: Two series of heterocyclic compounds were prepared, namely, [5-benzylidene-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (101), 5-(4-butoxybenzylidene)-2-(1-piperidinyl) -4-oxo-1,3-thiazolidine (102), 5-(4-hexyloxybenzyl-idene)-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (103), 5-(4-octyloxybenzyl-idene)-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (104),5-(4-decyl-oxybenzylidene)-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (105)] (series 1) and [5-benzylidene-2-(1-morpholinyl)-4-oxo-1,3-thiazolidine (106), 5-(4-butoxybenzylidene)-2-(1- morpholinyl)-4-oxo-1,3-thiazolidine (107), 5-(4-hexyloxybenzylidene)-2-(1-morpholinyl)-4-oxo-1,3-thiazolidine (108), 5-(4-octyloxybenzyl-idene)-2-(1-morpholinyl)-4-oxo-1,3-thiazolidine (109) and 5-(4-decyloxybenzylidene)-2-(1- morpholinyl)-4-oxo-1,3-thiazolidine (110)] (series 2). The chemical structures of these prepared compounds were elucidated via the conventional tools of analysis, [Elemental analysis, FTIR, 1H-NMR and Mass spectroscopy]. Their efficiency as antioxidants for the base oil sample was studied. They were added to the base stock sample with different concentrations (100, 200 and 300 ppm) at a specific temperature (120 oC) with different time intervals (24, 48, 72 and 96 hours).
The relation between these three concentrations and their efficiency toward the oxidation stability of the base oil was studied. The oxidation stability of the base oil sample (without and with additives) has been monitored, via measuring the change in total acid number (TAN) and viscosity.
The results obtained as the following:
Increasing the oxidation time, always increase both of the total acid number and the viscosity of the base stock.
The synthesized antioxidants proved to be successful in controlling the oxidation stability of the base stock.
The oxidation inhibition efficiency of these compounds depends on their structures.
It is noticed that the most effective compound is (110). The order of increasing oxidation stability is shown as follows:
110 > 109 > 108 > 107 > 106 > 105 > 104> 103 > 102 > 101.
The data reveals that the most effective concentration of the synthesized antioxidants is 300 ppm.
3- The third part emphasized on studying some of the quantum chemical calculations [EHOMO, ELUMO and energy gap (ΔE) (ELUMO-EHOMO)] for the prepared compounds. This theoretical study gave good reasonable correlation with the results obtained by total acid number (TAN) and viscosity.
4- The fourth part included the preparation and characterization of poly o-dodecyloxyaniline via FTIR, 1H-NMR spectroscopy, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The evaluation of it as viscosity index improver and pour point depressant was studied and it was found that the viscosity index and the efficiency as pour point depressant increase with increasing the concentration (0.1%, 0.3% and 0.4% by weight).