OVERBASED METAL CARBOXYLATE CALCITE-CONTAINING GREASES
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.