Overbased metal carboxylate calcite-containing greases

Abstract

Grease precursors of overbased alkaline earth metal carboxylates are prepared by reacting an alkaline earth metal base and a carboxylic acid in the presence of a hydrocarbon liquid, a polyol and an alcohol. The resulting grease precursor has amorphous calcium carbonate and a calcite content of greater than 10% by weight. At least one converting agent is added to the grease precursor containing elevated levels of calcite. This mixture is heated followed by the removal of water to form calcite-containing greases having a calcite content greater than 12.5% by weight.

1 . A grease precursor comprising:
 a hydrocarbon liquid;   a polyol;   an alcohol, wherein the alcohol has at least 8 carbon atoms; and   an overbased alkaline earth metal salt of a fatty acid comprising amorphous calcium carbonate and calcite, wherein the calcite is present in an amount of greater than 10% by weight of the grease precursor.   
     
     
         2 . The precursor of  claim 1  being substantially free of vaterite and aragonite. 
     
     
         3 . The precursor of  claim 1  having a TBN of greater than 400. 
     
     
         4 . The precursor of  claim 1 , wherein the fatty acid is a C 12 -C 22  fatty acid. 
     
     
         5 . The precursor of  claim 4 , wherein the fatty acid is oleic acid. 
     
     
         6 . The process of  claim 1 , wherein an alkaline earth metal of the overbased alkaline earth metal salt is selected from the group consisting of calcium, barium, magnesium and strontium. 
     
     
         7 . The precursor of  claim 1 , wherein the overbased alkaline earth metal salt is calcium oleate. 
     
     
         8 . The precursor of  claim 1 , wherein the alcohol is an aliphatic alcohol of at least 14 carbon atoms. 
     
     
         9 . The precursor of  claim 1 , wherein the polyol is a glycol or a glycol ether selected from the group consisting of diethylene glycol monobutyl ether, triethylene glycol, dipropylene glycol, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and mixtures thereof. 
     
     
         10 . A method for preparing a grease precursor, the method comprising the steps of:
 (a) preparing a mixture comprising a carboxylic acid, wherein the carboxylic acid is a fatty acid; a base oil; a polyol; and an alcohol, wherein the alcohol has at least 8 carbon atoms;   (b) neutralizing the carboxylic acid with an initial amount of alkaline earth metal base to form an alkaline earth metal carboxylate mixture;   (c) heating the alkaline earth metal carboxylate mixture;   (d) adding an additional amount of an alkaline earth metal base to the alkaline earth metal carboxylate mixture;   (e) carbonating the mixture to neutrality to form amorphous alkaline earth metal carbonate in the alkaline earth metal carboxylate mixture, wherein water generated in situ during carbonation promotes a conversion of the amorphous alkaline earth metal carbonate to calcite;   (f) repeating steps (d) and (e) at least one more time; and   (g) removing water from the alkaline earth metal carboxylate mixture to obtain a grease precursor having a an amount of calcite greater than 10% by weight.   
     
     
         11 . The method of  claim 10 , wherein the precursor is substantially free of vaterite and aragonite. 
     
     
         12 . The method of  claim 10  having a TBN of greater than 400. 
     
     
         13 . The method of  claim 10 , wherein the fatty acid is a C 12 -C 22  fatty acid. 
     
     
         14 . The method of  claim 13 , wherein the fatty acid is oleic acid. 
     
     
         15 . The method of  claim 10 , wherein the alkaline earth metal is selected from the group consisting of calcium, barium, magnesium and strontium. 
     
     
         16 . The method of  claim 10 , wherein the alkaline earth metal carboxylate mixture includes calcium oleate and calcium carbonate. 
     
     
         17 . The method of  claim 10 , wherein the alcohol is an aliphatic alcohol of at least 14 carbon atoms. 
     
     
         18 . The method of  claim 10 , wherein the polyol is a glycol or a glycol ether selected from the group consisting of diethylene glycol monobutyl ether, triethylene glycol, dipropylene glycol, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and mixtures thereof. 
     
     
         19 . A method of preparing a grease, the method comprising the steps of:
 preparing the grease precursor of  claim 10 ;   adding and mixing at least one conversion agent to the grease precursor to form a converted mixture, wherein the conversion agent is selected from the group consisting of a hydrocarbon oil, water and a C 1 -C 5  carboxylic acid;   heating the converted mixture; and   removing water from the converted mixture to obtain a grease having an amount of calcite greater than 12.5% by weight.   
     
     
         20 . A method for preparing a grease, the method comprising the steps of:
 (a) preparing a mixture comprising a carboxylic acid, wherein the carboxylic acid is a fatty acid, a base oil, at least one polyol and at least one alcohol, wherein the alcohol has at least 8 carbon atoms;   (b) neutralizing the carboxylic acid with an initial amount of alkaline earth metal base to form an alkaline earth metal carboxylate mixture;   (c) heating the alkaline earth metal carboxylate mixture;   (d) adding an additional amount of an alkaline earth metal salt to the alkaline earth metal carboxylate mixture;   (e) carbonating the mixture to neutrality to form amorphous alkaline earth metal carbonate in the alkaline earth metal carboxylate mixture, wherein water generated in situ during carbonation promotes a conversion of the amorphous alkaline earth metal carbonate to calcite;   (f) repeating steps (c) and (d) at least one more time;   (g) removing water from the alkaline earth metal carboxylate mixture to obtain a grease precursor having an amount of calcite greater than 10% by weight;   (h) adding and mixing at least one conversion agent to the grease precursor to form a converted mixture, wherein the conversion agent is selected from the group consisting of a hydrocarbon oil, water and a C 1 -C 5  carboxylic acid;   (i) heating the converted mixture of (h); and   (j) removing water from the converted mixture to obtain a grease having an amount of calcite greater than 12.5% by weight.   
     
     
         21 . The grease precursor prepared in accordance with the process of  claim 10 . 
     
     
         22 . The grease prepared in accordance with the process of  claim 20 . 
     
     
         23 . A method for preparing a grease, the method comprising the steps of:
 (a) preparing a mixture comprising a carboxylic acid, wherein the carboxylic acid is a fatty acid, a base oil, at least one polyol and at least one alcohol, wherein the alcohol has at least 8 carbon atoms;   (b) neutralizing the carboxylic acid with an initial amount of alkaline earth metal base to form an alkaline earth metal carboxylate mixture;   (c) heating the alkaline earth metal carboxylate mixture;   (d) adding an additional amount of an alkaline earth metal salt to the alkaline earth metal carboxylate mixture;   (e) carbonating the mixture to neutrality to form amorphous alkaline earth metal carbonate in the alkaline earth metal carboxylate mixture, wherein water generated in situ during carbonation promotes a conversion of the amorphous alkaline earth metal carbonate to calcite;   (f) repeating steps (d) and (e) at least one more time;   (g) removing an amount of water from the alkaline earth metal carboxylate mixture to obtain a grease precursor having an amount of calcite greater than 25% by weight;   (h) adding and mixing the grease precursor to at least an amount of an overbased calcium carboxylate to form a grease precursor-overbased calcium carboxylate mixture, wherein the overbased calcium carboxylate contains amorphous calcium carbonate and is substantially free of calcite;   (i) adding and mixing at least one conversion agent to the grease precursor-overbased calcium carboxylate mixture to form a converted mixture, wherein the conversion agent is selected from the group consisting of a hydrocarbon oil, water and a C 1 -C 5  carboxylic acid;   (j) heating the converted mixture of (i); and   (k) removing water from the converted mixture to obtain a grease having an amount of calcite greater than 8.0% by weight.   
     
     
         24 . A method for preparing a grease precursor, the method comprising the steps of:
 (a) preparing a mixture comprising a carboxylic acid, wherein the carboxylic acid is a fatty acid; a base oil; a polyol; and an alcohol, wherein the alcohol has at least 8 carbon atoms;   (b) neutralizing the carboxylic acid with an initial amount of alkaline earth metal base to form an alkaline earth metal carboxylate mixture;   (c) heating the alkaline earth metal carboxylate mixture;   (d) adding an additional amount of an alkaline earth metal base to the alkaline earth metal carboxylate mixture;   (e) carbonating the mixture to neutrality to form amorphous alkaline earth metal carbonate in the alkaline earth metal carboxylate mixture, wherein water generated in situ during carbonation promotes a conversion of the amorphous alkaline earth metal carbonate to calcite;   (f) repeating steps (d) and (e) at least one more time; and   (g) removing water from the alkaline earth metal carboxylate mixture to obtain a grease precursor having a an amount of calcite greater than 25% by weight.   
     
     
         25 . A method of preparing a grease, the method comprising the steps of:
 preparing the grease precursor of  claim 24 ;   adding and mixing the grease precursor to at least an amount of an overbased calcium carboxylate to form a grease precursor-overbased calcium carboxylate mixture, wherein the overbased calcium carboxylate contains amorphous calcium carbonate and is substantially free of calcite;   adding and mixing at least one conversion agent to the grease precursor to form a converted mixture, wherein the conversion agent is selected from the group consisting of a hydrocarbon oil, water and a C 1 -C 5  carboxylic acid;   heating the converted mixture; and   removing water from the converted mixture to obtain a grease having an amount of calcite greater than 8.0% by weight.