الفهرس 
ACKNOWLEDGEMENTOnly 14 pages are availabe for public view
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Abstract
The aim of the present work is to synthesize some of new heterocyclic compounds like Thiophene and its derivatives to study their efficiencies as antioxidant additives for Lubricating oils. The original work of the thesis is divided into two parts : Part I: A facile synthesis of functionalized 4-hydroxyphenylazo-2-substituted-thiophenes and their impact on lubricating oils. In the present research, we focused on the synthesis of different substituted thiophene derivatives incorporating a phenolic moiety at the 4-postion (4-hydroxyphenylazo) to evaluating their efficiencies as antioxidants for the Egyptian lubricating oil. The synthesized 3-hydroxy-4-hydroxyphenylazo-thiophene compounds were applied as antioxidant additives for lubricating oil. The oxidative products where determined in terms of the total acid number (T. A. N.) and compared with the lubricating oil without additives. The results of T.A.N. indicated that: when the synthesized thiophene additives were added to the oil under investigation, the oxidation products increased with time but less than the case of without additives. Part II : Synthesis of some new heterocyclic derived based on 4-aminobenzoate ester. 2-Oxo-2-phenylethyl 4-aminobenzoate 1 has been diazotized and coupled with various methylene components to furnish the hydrazono derivatives which underwent condensation with hydrazine hydrate, afforded the corresponding azopyrazoles In addition, the diazotized 4-aminobenzoate ester was coupled with barbituric and thiobarbituric acids to give the hydrazono-pyrimidines The diazo-coupling with thiocarbamoyl derivative to from the hydrazono derivative which reacted readily with phenacyl chloride and/or chloroacetonitrile to afford azothiophenes.