Overbased materials in ester media

Abstract

An overbased material is prepared in a liquid ester medium which is subject to saponification upon exposure to strong base, by preparing a mixture of an acidic material having at least about 8 carbon atoms in a volatile oleophilic medium which is substantially inert to base; adding to the mixture a stoichiometric excess of a metal base; adding to the mixture a gaseous acidic material under conditions to react with substantially all of the stoichiometric excess of the metal base; and adding the liquid ester medium to the resulting material.

What is claimed is: 
     
       1. A process preparing an overbased material in a liquid ester medium which is subject to saponification upon exposure to strong base, comprising: (a) preparing a mixture of an acidic material having at least about 8 carbon atoms in a volatile oleophilic medium which is substantially inert to base;   (b) adding to the mixture a stoichiometric excess of a metal base;   (c) adding to the mixture a gaseous acidic material under conditions to react with substantially all of the stoichiometric excess of the metal base; and   (d) adding said liquid ester medium to the resulting material.   
     
     
       2. The process of claim 1. wherein at least a portion of the volatile oleophilic medium is removed before the liquid ester medium is added. 
     
     
       3. The process of claim 1. wherein at least a portion of the volatile oleophilic medium is removed after the liquid ester medium is added. 
     
     
       4. The process of claim 3. wherein substantially all of the volatile oleophilic medium is removed. 
     
     
       5. The composition of claim 1. wherein the liquid ester medium is a vegetable oil. 
     
     
       6. The process of claim 5. wherein the vegetable oil is castor oil, rapeseed oil, tall oil, or sunflower oil. 
     
     
       7. The process of claim 1. wherein the liquid ester medium is a synthetic ester. 
     
     
       8. The process of claim 7. wherein the synthetic ester is an ester of an alkanoic acid having at least about 8 carbon atoms and a polyol having at least 3 carbon atoms and at least 3 hydroxy groups. 
     
     
       9. The process of claim 8. wherein the synthetic ester is the ester of trimethylolpropane or di-trimethylolpropane with iso-nonanoic acid or neodecanoic acid. 
     
     
       10. The process of claim 1 wherein the acid material containing at least about 8 carbon atoms is a carboxylic acid, sulfonic acid, phosphorus-containing acid, phenol, or mixtures thereof. 
     
     
       11. The process of claim 10. wherein the acid material is a hydrocarbylsubstituted benzenesulfonic acid. 
     
     
       12. The process of claim 10. wherein the acid material is a hydrocarbylsubstituted salicylic acid. 
     
     
       13. The process of claim 10. wherein the acid is a condensate of a phenol and glyoxylic acid. 
     
     
       14. The process of claim 1. wherein the volatile oleophilic medium is a hydrocarbon liquid having a normal boiling point of at most about 200° C. 
     
     
       15. The process of claim 1. wherein the volatile oleophilic medium is mineral spirits, kerosene, toluene, or xylene. 
     
     
       16. The process of claim 1. wherein included in the mixture of step (a) is a promoter in an amount suitable to promote the incorporation of the acidic gaseous material. 
     
     
       17. The process of claim 16. wherein the promoter comprises at least one alcohol of 1 to about 6 carbon atoms or a mixture thereof with water. 
     
     
       18. The process of claim 1. wherein the metal base is an oxide or hydroxide of an alkali metal, an alkaline earth metal, zinc, or cadmium. 
     
     
       19. The process of claim 18. wherein the metal base is an oxide or hydroxide of calcium or magnesium. 
     
     
       20. The process of claim 1. wherein the amount of the metal base is about 1.1 to about 40 equivalents per equivalent of the acid material. 
     
     
       21. The process of claim 1. wherein the gaseous acidic material is carbon dioxide, sulfur dioxide, or sulfur trioxide, hydrogen chloride, or hydrogen sulfide. 
     
     
       22. The process of claim 21. wherein the gaseous acidic material is carbon dioxide. 
     
     
       23. The process of claim 1. wherein the gaseous acidic material is added by bubbling into a stirred reaction mixture. 
     
     
       24. The process of claim 1. wherein the mixture is maintained at about 25 to about 150° C. during the addition of the gaseous acidic material. 
     
     
       25. The process of claim 1. further comprising, after step (c), converting the overbased material to a gel. 
     
     
       26. The product of the process of claim 1.