Ministry of Higher Education and Scientific Research University of Baghdad – College of Science Department of Chemistry ’ Synthesis of Lubricant s Additives A Thesis Submitted to the College of Science - University of Baghdad In Partial Fulfillment of the Requirements for Degree of Doctor Philosophy in Organic Chemistry By Zainab Abdulzahra Khuthair AL-Messri B.Sc. (Baghdad University 1994) M.Sc. (AL-Nahrain University 1999) Supervisors Prof. Dr. Mohammed R. Ahmad Prof. Dr. Abdul Halim A-K Mohammed 2013 A. D. 1434 A. H. ﻢﻴﻈِ ﻌﻟا ﻲِﻠﻌﻟا ﻪﱠﻠﻟا قﺪﺻ ُ َ ﱡ َ ُ َ َ َ ءاﺮﻌﺸﻟا ةرﻮﺳ ﻦﻣ Dedicate to: The light of my life… My father with love and respect & The real friend and sister… Israa with appreciation Zainab ACKNOWLEDGEMENTS I would like to express my gratitude to the many people that helped in different ways towards the completion of this work. My primary thanks to my supervisors Prof. Mohammed R. Ahmad and Prof. Abdul Halim A-K Mohammed, for their support, guidance and discussion of my work. I also thank Prof. Yousif Ali, who helped me not only with this thesis, but with acquiring scientific knowledge and skills. My deep gratitude to Prof. Mousa Almousawi, Prof. Abdul Jabar Kadir, Prof. Issam M.A. Shakir, Ass. Prof. Basim .I. Al- Abdali, Prof. M. Shanshal, and Ass. Prof. Mohammed H. Al-Ameri for their supporting, and encouragement. Sincere thanks to the Ministry of Higher Education and Scientific Research for providing free, and full-text access to the scientific journals according to Iraq Virtual Science Library. Thanks are offered to the Department of chemistry, College of Science, University of Baghdad for providing the facilities. I gratefully acknowledge financial support by the Petroleum R&D Center /Ministry of Oil. A special thanks to Mr. Salah M. Ali for his assistance and encouragement. I am very grateful to Dr. Abdulkareem Mohammed Ali, for modifying a domestic microwave oven to microwave irradiation reactor. My special thanks, and gratitude to Prof. Issam M.A. Shakir and Prof. Nagham S. Turkie , for the (ANOVA) tests. Thanks are also due to Midland Refineries Company/ Iraq for providing the base oils and the analyses of oxidation stability, especially Mr. Ayad A. Mohamad , Mr. Yousif T. Abdulhameed, and the lab technicians and chemists (Bacil Al-Dabbagh, Mohammed Ahamad, Basam Al-Qaicy, Mohammed Saaed, Mustafa Al-Bassam and Ahmed Abdulzahra) who helped in the analysis. I am very grateful, and appreciate for all the help and support from Ass. Prof. Suaad M. Al-Majidi. Sincere thanks to Prof. Intisar Altamemi, Prof. Ahlam M. Farhan, Prof. Khulood Al-Saadie, Dr. Thanaa Almuamen, and Mrs. Hanaa J. Hamoudi for their supporting and encouragement. A special thanks to Dr. Ghadah A. Yiseen, Middle East Technical university , Turkey and to Dr. Naeema J. Lami, Cardiff University, U.K., for NMR analysis. Also, I would like to thank Ms. Muneera, and Mrs. Haifaa for their kind assistance in Infra red analysis. Sincere thanks goes to my best friends (Israa, Saba, Nada, Jwan, Thikra, Hind, Dalia, Huda, Nasreen, Hiba, and Yasmeen), and to my colleagues (Mr. Ali Muayad, Muntader, Rafid, Ali Saad and Oday) for their continuous support and help. Finally, my respect and appreciation to my professor and mother Prof. Suad M. AL-Aaraji, and to my dear father. Summary Overbased detergent additives were synthesized and investigated as viscosity index improvers, and pour point depressant. New antioxidant additives containing pyranopyrazole and pyranopyrimidine moieties were synthesized and evaluated as lubricating oil additives. A series of overbased magnesium fatty acids (D1-D7) such as caprylate, caprate, laurate, myristate, palmitate, stearate and oleate, were synthesized by the reaction of the fatty acids in toluene / ethanol solvent mixture (9:1vol./vol.) with magnesium oxide and carbon dioxide gas at 60 oC in the presence of ammonia solution. Moreover overbased calcium palmitate, stearate and oleate (D8-D10), were synthesized by the same method, using calcium oxide and calcium hydroxide instead of magnesium oxide. The prepared detergent additives were characterized and confirmed by FTIR, and 1HNMR. All these compounds were evaluated by blending each additive in various concentrations (1-5% wt/wt) with medium lubricant oil fraction (60 stock) supplied by Iraqi Midland Refineries Company. The total base number (TBN, mg of KOH/g oil) was determined. Overbased magnesium palmitate D5, oleate D6, and stearate D7 detergents gave the higher TBN and efficiency. The oil blends with 2% of overbased magnesium palmitate and overbased magnesium stearate detergents were proved to have excellent oxidation stability compared with the blends of standard antioxidant supplied by Midland Refineries Company. I The efficiency of the prepared overbased magnesium palmitate and overbased magnesium stearate as viscosity index improvers, were investigated. It was found that the efficiency of the prepared compound as viscosity index improvers increases with increasing the concentration of additives and with increasing the molecular weight of prepared compounds. The overbased magnesium stearate D7 in 5 wt.% concentration gave the higher efficiency as viscosity index improvers, and a good pour point depressant. Antioxidant additives containing pyranopyrazole and pyranopyrimidine moieties, were synthesized from 2-(4- hydroxylbenzylidine) malononitrile (S3), which was obtained from the reaction of 4-hydroxy benzaldehyde and malononitrile in presence of pipridine in ethanol under microwave irradiation. Reaction of S3 with three different types of carbanion compounds 3-methyl-1-phenyl-2-pyrazolin-5-one (S1), 3-methyl -2-pyrazolin-5-one (S2), 5,5-dimethyl-1,3-cyclohexandion (dimedone) and pyrimidine- 2,4,6(1H,3H,5H)-trione (barbituric acid) under microwave irradiation gave 6-amino-4-(4-hydroxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4- dihydropyrano[2,3-c]pyrazole (A1), 6-amino-4-(4-hydroxy phenyl)-5- cyano-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole (A11), 5-(4- hydroxyphenyl)-8,8-dimethyl-8,9-dihydro-3H-chromeno-5-cyano-1,4- dihydropyrano[2,3-c]pyrazole (A۱۷) and 7-amino-5-(4-hydroxyphenyl)- 2,4-dioxo-2,3,4,5-tetrahydro-1H-pyrano[2,3-d]pyrimidine-6-carbonitrile (A26) respectively. The compound A1 was reacted with formic acid, formamide and ammonium thiocyanate under microwave irradiation to prepare 4-(4- hydroxyphenyl)-3-methyl-1-phenyl-4,6-dihydro-pyrazolo[3',4':5,6]pyrano II [2,3-d]pyrimidine-5-one (A2), 4-(4-hydroxyphenyl)-3-methyl-1-phenyl- 4,6-dihydro-pyrazolo[3',4':5,6]pyrano[2,3-d]pyrimidine-5-imine (A3) and N-[4-(4-hydroxyphenyl)-3-methyl-1-phenyl-7-thioxo-7,8dihydropyrazolo [3',4':5,6]pyrano[2,3-d]pyrimidine-5-yl]thiourea (A4) respectively. Moreover the compound (A1) was then reacted with different aromatic aldehydes which gave the corresponding Schiff’s base derivatives (A5- A10). Schiff’s base derivatives (A12-A16) were obtained from the reaction of the compound A11 with different aromatic aldehydes in the presence of drops of acetic acid under microwave irradiation. Compounds (A18-A20) and (A21-A25) were synthesized in a similar manner that used for preparation of (A2-A4) and (A5-A10) respectively. Most of the prepared compounds were characterized by FTIR, 1HNMR, 13CNMR and evaluated as antioxidant additives by blending 1% of each compound with base oil 60 stock. The oxidation stability of blends was examined according to Institute of Petroleum testing method IP 280. Inhibited oil was subjected to severe oxidation condition in the presence of a soluble iron and copper catalyst at 120ο C for 164 hours while being subjected to a constant one- liter/hour flow of oxygen. From this test the volatile acids, the acidity of the oil and the precipitated sludge were measured and their values were used to calculate the total oxidation products (TOP). The oxidation stability study revealed that many of the tested compounds showed good to moderate antioxidant activities. While, the derivatives A4, A5, A7, A20, A21, A23, and A26 showed better oxidation stability than the standard antioxidant supplied by Midland Refineries Company. III List of Contents Chapter One 1.1 Lubricants 1 1.1.1 Lubricant Properties 2 1.1.1.1 Viscosity 2 1.1.1.2 Viscosity Index 2 1.1.1.3 Density and Gravity 3 1.1.1.4 Pour Point 4 1.1.1.5 Volatility and Flash Point 4 1.1.1.6 Total Base Number 4 1.1.1.7 Oxidation Stability 5 1.1.2 Lubricants chemistry 7 1.1.3 Lubricants production 9 1.1.4 Lubricants Formulation 11 1.2 Additives 13 1.2.1 Detergents 15 1.2.2 Dispersants 15 1.2.3 Antiwar Additives 15 1.2.4 Rust and Corrosion Inhibitors 16 1.2.5 Viscosity Modifiers 16 1.2.6 Pour Point Depressants 16 1.2.7 Foam Inhibitors 16 1.2.8 Oxidation Inhibitors 17 1.3 Overbased detergent 17 1.3.1 Synthesis of Overbased Detergents 18 1.3.2 Overbasing Description 19 IV 1.3.3 Overbased Detergent Structure 19 1.3.4 Overbased Detergent Types 20 1.3.4.2 Phenates 20 1.3.4.3 Carboxylate and Salicylates 21 1.4 Antioxidants 22 1.4.1 Oxidation Mechanism 24 1.4.1.1 Initiation of the Radical Chain Reaction 24 1.4.1.2 Propagation of the radical chain reaction 25 1.4.1.3 Chain branching 25 1.4.1.3 Chain branching 26 1.4.1.4 Termination of the radical chain reaction 26 1.4.2 Oxidation Inhibition 27 1.4.2.1 Radical Scavengers 27 1.4.2.1.1 Phenols 27 1.4.2.1.2 Amines 28 1.4.2.2 Peroxide Decomposers 30 1.4.2.3 Metal deactivators 31 1.5 Pyrazole 32 1.6 Pyranopyrazoles 33 1.7 Chromene 38 1.8 2-Amino-3-cycano-4-aryl-7,7-dimethyl-5,6,7,8-tetrahydro 40 chromene 1.9 Aim of the work 44 Chapter Two 2.1 Materials 45 2.1.1 Chemicals 45 V