Lubricating oil compositions and concentrates and the use thereof

#This invention relates to oleaginous compositions of enhanced performance characteristics, to additive concentrates for enhancing the performance characteristics of oleaginous base fluids (e.g., lubricants and functional fluids), and to methods of achieving such enhanced performance characteristics.

#Over the years the demand for performance improvements in lubricating oils and functional fluids has persisted and, if anything, progressively increased. For example, lubricating oils for use in internal combustion engines, and in particular, in spark-ignition and diesel engines, are constantly being modified and improved to provide improved performance. Various organizations including the SAE (Society of Automotive Engineers), the ASTM (formerly the American Society for Testing Materials) and the API (American Petroleum Institute) as well as the automotive manufacturers continually seek to improve the performance of lubricating oils. Various standards have been established and modified over the years through the efforts of these organizations. As engines have increased in power output and complexity, and in many cases decreased in size, the performance requirements have been increased to provide lubricating oils that will exhibit a reduced tendency to deteriorate under conditions of use and thereby to reduce wear and the formation of such undesirable deposits as varnish, sludge, carbonaceous materials and resinous materials which tend to adhere to various engine parts and reduce the operational efficiency of the engine.

#Current objectives include the development of additive formulations and lubricant compositions, especially crankcase lubricants and crankcase lubricant additive packages, capable of achieving these stringent performance requirements without requiring use of heavy metal-containing components, such as zinc dihydrocarbyl dithiophosphates. Because of environmental and conservational concerns, much emphasis of late has been devoted toward finding ways of eliminating heavy metal-containing components from lubricants and functional fluids. Not only do heavy metals pose environmental and toxicological problems (e.g., problems arising in the event of spillage, leaks, etc.), but their presence in used oils complicates used oil reclamation procedures.

#The following examples illustrate methods by which overbased metal detergents can be prepared.

#(a) Into a reaction vessel is charged 646 g of solvent refined 500N lubricating oil (a mixture of alkyl aromatics, naphthenes, and paraffins). At 75.degree. F., 150.8 g of oleum (.about.27.6% SO.sub.3) is charged to the reaction vessel over a 10-minute period. The reaction temperature is allowed to rise, generally to about 100.degree. F. Afterwards, 12.3 mL of water and 540 mL of Chevron 265 thinner (a mixture of aromatics, naphthenes, and paraffins) is added to the system. The system is maintained at 150.degree. F. for one hour. At this time, 125 mL of a 25 weight percent aqueous solution of sodium hydroxide is added to the system. The reaction mixture is maintained at 150.degree. F. for one hour. After settling, the aqueous layer is removed and the organic solution is then maintained at temperature for at least one additional hour. After this period, any additional aqueous layer which settles out is also removed. The system is stripped at 350.degree. F. and atmospheric pressure with an air sweep to yield sodium hydrocarbyl sulfonate. This product is purified by dissolving the sodium hydrocarbyl sulfonate in 330 mL of aqueous secondary butanol. An aqueous solution (160 mL) containing 4% by weight of sodium chloride is added to the system. The resultant mixture is heated to 150.degree. F. and maintained at this temperature for two hours. After settling, brine is removed. An additional 80 mL of an aqueous solution containing 4% by weight of sodium chloride is added to the system. The system is heated to 150.degree. F. and maintained at this temperature for one hour. After settling, brine is removed. Water (220 mL) is then added to the system and the mixture heated to 150.degree. F. and maintained at this temperature for another one hour period. Thereafter, water and unsulfonated oil layer are removed leaving an aqueous secondary butanol solution containing sodium hydrocarbyl sulfonate.

#(b) To an aqueous secondary butanol solution containing sodium hydrocarbyl sulfonate produced as in (a) is added 500 mL of a solution containing water, secondary butanol and approximately 10% of calcium chloride. The system is heated to 150.degree. F. and maintained at this temperature for one hour. After settling, brine is removed. Water (240 mL) and 170 mL of an aqueous solution containing 40% by weight of calcium chloride is added to the system, the system is heated to 150.degree. F., and the system is maintained at this temperature for at least one additional hour. After settling, brine is removed. Water (340 mL) and 170 mL of an aqueous solution containing 40% by weight of calcium chloride is added to the system. The system is heated to 150.degree. F. and maintained at this temperature for at least one hour. After settling, brine is removed. Water (340 mL) is then added to the system and the system is heated to 150.degree. F. where it is maintained for one additional hour. After settling, the aqueous layer is removed. Next, an additional 340 mL of water is added to the system and the system is heated to 150.degree. F. and maintained at this temperature for one hour. After settling, the aqueous layer is removed. The aqueous secondary butanol solution is then stripped at elevated temperatures and reduced pressures to yield overbased calcium hydrocarbyl sulfonate.