ABSTRACT
I. Introduction ........................................................................................................... 438 II. Chemistries of Detergents and Dispersants .......................................................... 439 III. Types of Metallic Detergents ................................................................................ 439
A. Sulfonates .................................................................................................. 439 B. Phenates..................................................................................................... 442 C. Salicylates.................................................................................................. 442 D. Phosphonates and Thiophosphonates........................................................ 443 E. Other Detergents ....................................................................................... 444
IV. Types of Ashless Dispersants................................................................................ 445 A. Succinimides.............................................................................................. 445 B. Esters ......................................................................................................... 446 C. Oxazolines ................................................................................................. 447 D. Mannich Condensates ............................................................................... 448 E. Graft Ethylene-Propylene Copolymers .................................................... 449 F. Thiophosphonates...................................................................................... 450 G. Other Dispersants ...................................................................................... 450
V. Solution Behavior of Detergents and Dispersants in Oils ................................... 451 A. Micellar Properties of Sulfonate Detergents in Hydrocarbon
Solvents ..................................................................................................... 451 B. Counter Ion Effect on Sulfonate Detergent Micellar Stability ................ 452 C. Thermodynamic Energetics of Micellar Formation Process .................... 452 D. Micellar Properties of Other Metallic Detergents in Hydrocarbon
Solvents ..................................................................................................... 453 E. Micellar Properties of Ashless Dispersants .............................................. 453 F. Rigidity of Metallic Detergent Micelles................................................... 454 G. Effect of Overbasing on Micellar Structures............................................ 454 H. Overbasing Mechanism............................................................................. 455
VI. Action Mechanisms of Metallic Detergents and Ashless Dispersants................. 455 A. Acid-Base Neutralization Mechanisms in Lubricating Oils.................... 455 B. Rate of Alkalinity Depletion in Oils......................................................... 456 C. Peptization Mechanisms to Keep Insoluble Particles in Suspension....... 457 D. Prevention of Varnish and Lacquer Deposition Formation ...................... 458 E. As Friction and Wear Reduction Agents .................................................. 458 F. Solubilization of Polar Species ................................................................. 458
VII. Additive-Additive Interactions ............................................................................. 459 A. Strength and Type of Additive-Additive Interactions .............................. 459 B. Effect of Additive-Additive Interactions on Oxidation Stability............. 460 C. Effect of Additive-Additive Interactions on Antiwear and Anti-EP
Performance............................................................................................... 460 D. Effect of Additive-Additive Interactions on High-Temperature Deposit
Formation .................................................................................................. 461 VIII. General Formulations Utilizing Detergents and Dispersants in Lubricants ........ 462
A. Use of Detergents and Dispersants in Engine Oil Formulations ............. 462 B. Use of Detergents and Dispersants in Automatic Transmission
Fluids and Gear Oils ................................................................................. 464 References ....................................................................................................................... 465
I. INTRODUCTION
There are a large number of different lubricants in the market. Lubricants today have found their applications in two major areas-automotive and industrial. Major automotive lubricants include engine oils (commonly called crankcase oils), transmission fluids (automatic or manual), hydraulic fluids, and gear oils. Engine oils can be further classified into gasoline engine oils, light-duty and heavy-duty diesel engine oils, railroad diesel engine oils, marine diesel engine oils, natural gas engine oils, aircraft engine oils, and two-cycle engine oils. For industrial applications, in addition to hydraulic fluids and gear oils, the products include metalworking fluids, process oils, turbine oils, circulation oils, compressor oils, and greases.
