CA2042196A1 - Process for preparing alkali metal and alkaline earth metal complex greases - Google Patents

Abstract

RBP File No. 492-499 ABSTRACT

A process for preparing an alkali metal or alkaline earth metal complex soap for use in the preparation of an alkali metal or alkaline earth metal complex grease is disclosed. An alkali metal or alkaline earth metal soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap is reacted in the presence of a base oil with a complexing amount of a complexing acid. The reaction produces the respective alkali metal or alkaline earth metal complex soap and fatty acid. A neutralizing amount of the respective alkali metal or alkaline earth metal base is added to neutralize the fatty acid.

Description

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; RBP File No. 492-499 Title: PROCE:S5 FOR PREPARING AL}~ALI ME:TAL A~D
ALKALINE EARTH NETAL COMPLE~ ~REA~S
.
.` FIELD OF q~ VE~ION
This invention relates to a process for ;, preparing alkali metal and alkaline earth metal complex greases and, in particular, lithium complex greases.
~'~ Background to the Invention ` Alkali metal and alkaline earth metal complex `~ 10 greases (hereinafter "complex greases") are known in the ~ art. Today, lithium, barium, calcium and sodium complex ; gre~ses are in commercial use. The most important of these greases, and the ones upon which more attention has been focused, are the lithium complex greases. I~he history and development of these lithium greases is ;, discussed in the following articles: I.D. Campbell and G.L. Harting, A New Generation of Lithium Greases, The Lithium Complex Greases, NLGI Spokesman, 40t6), 193 Sept.
1976; M. Ehrlich and T.G. Musilli, ~he Development of Lithium Complex Grease, NLGI Spokesman 44, 97, 1980; and W.E. Snider, Lithium Complex Grease, NLGI Spokesman, 49(6) 247, 1985.
Complex greases and in particular lithium complex greases are characterized as having very high dropping points and relatively high water resistance.
Various methods have been developed to prepare lithium complex greases.
According to one method, the acids which are i used to prepare the lithium complex soap are dissolved in at least a portion of the lubricating oil which`is to be used to form the grease. These acids are then co-neutralized in the presence of a base. Examples of such processes are disclosed in Vnited States Patent Nos.
3,298,g53; 3,681,242; 3,929,651; 4,435,299; 4,444,669;
4,582,619 and 4,597,881. See also Martin McCormick et al Contactor Process for Lithium Grease, NLGI Spokesman 49(4), 144, 1985. The processes disclosed in these documents are operated at different temperatures and use :, ~ 2 --r :;
various different acids to prepare the lithium complex grease. In addition, United States Patent No. 414441669 :, and McCormick et al each disclose operating such a co-` neutralization process at elevated pressures.
As disclosed in United States Patent No.
.l 4139219671 a complex lithium grease may be prepared by ,f dissolving a fatty acid in a lubricating oil and reacting this mixture with aqueous lithium hydroxide solution.
; This mixture is dehydrated and a dicarboxylic acid is ~ 10 added to this mixture. Subsequently, a further aliquot of ;j~ aqueous lithium hydroxide solution is added and the mixture is allowed to react. The mixture is again ; dehydrated.
~ United States Patent No. 319291651 discussed f. 15 above also discloses, in an alternate embodiment, a process whereby lithium hydroxide is added in aliquots to r: ` the mixture. According to this embodiment, a hydroxy fatty acid and a dicarboxylic acid in at least a portion of the Iubricating oil are co-neutralized with lithium 20 hydroxide. The mixture is then dehydrated. Subsequently, a salicylate ester is added and converted to the dilithium salicylate salt by the addition of lithium hydroxide.
United States Patent No. 3~791~973 discloses a ,~ .
method to produce a multi purpose grease with high 25 dropping point. According to this disclosure, the grease f;' iS prepared by using as thic~ener a combination of a lithium soap of, for example, 12 hydroxystearic acid and a lithium soap of, for example, azelaic acid, which is prepared using a particular sequence of steps. As 30 disclosed in the patent, the base oil is charged to a r grease kettle. A C12 to C22 hydroxy fatty acid is added to ~; the oil. The hydroxy fatty acid is neutralized with a hot : saturated aqueous solution of lithium hydroxide. The mixture is dehydrated at elevated temperatures and then 35 cooled. A C2 to C12 aliphatic dicarboxilic acid is added to the mlxture and ~tirred. Subsequently, a ~econd portion of , ~ 3 ~ 2~

lithium hydroxide is added as a hot aqueous saturated solution. The grease is again dehydrated at an elerated temperature of about 280 - 300F. Subsequent to the dehydration, the temperature of the reaction mixture is pre~erably raised to 380 - ~00F to ensure optimum soap dispersion and improve yields. The patent discloses that two competing reactions occur. These are (i) incorporation of either the dicarboxylic acid or its monolithium soap into the crystal lattice of the lithium soap of the hydroxy acid thereby altering the structure of the acid;
and, (ii) the conversion of the dicarboxylic acid to its dilithium soap. The sequence of steps disclosed in the patent favours the first of these two competing reactions when the saponification reaction occurs at a temperature of about 220 - 230F (104 - 110C).
United States Patent No. 3,809,650 discloses a process for preparing a high temperature grease comprising neutralizing a lower alkyl ester of a hydroxy fatty monocarboxylic acid with an excess of metal base selected from the group consisting of alkali metal bases and alkaline earth metal bases in an oil vehicle. The reaction is conducted at elevated temperatures in the range of 300 to 400F (14~ - 204C) in a closed system.
Subsequently, an alkyl ester of an aliphatic dicarboxylic acid is added to the soap-thickened oil composition. The resultant mixture is heated to a temperature in the range of 350 to 450F (177 - 232C) in a closed sys~em.
Each of the processes known in the art has various disadvantages. Some of the processes do not result in the production of a grease having a consistently high dropping point. Further, other processes do not result in the production of a grease having good mechanical stability. Further, other processes have poor grease yqelds. Some proeesses involve two or more dehydration steps which result in additional process steps being required to reduce the water content of a grease.

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Further, some processes result in foaming which creates handling problems in subsequent operations.
It is desirable to provide a process for `. producing complex greases and, in particular, lithium complex greases wherein the resulting greases have consistently high dropping points as defined by ASTN D-2265, good mechanical stabilities (i.e. penetration and shear strength as measured by ASTM D-217) and good grease : yields as defined by ASTM D-218.
$ 10 It is also desirable to provide a process for producing complex greases and, in particular, lithium complex greases which reduces the number of dehydration ; steps which is requiréd. Further, it is also desirable to provide a process for producing lithium complex greases wherein foaming is d~creased. In addition, it is also desirable to affect the complex soap formation at lower temperatures.
Summary of the Invention Complex greases having consistently high dropping points, good mechanical stabilities and good grease yields may be obtained by utilizing a two-step process. The first step of this process is an exchange reaction wherein an alkali metal or alkaline earth metal fatty acid soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap is ` reacted with a complexing amount of the complexing acid to ` produce an alkali metal or alkaline earth metal complex soap and a fatty acid. Preferably, the fatty acid soap has i from 12 to 24 carbon atoms. The fatty acid may also comprise minor proportions of poly-unsaturated fatty acids. In the second step, a neutralizing amount of the respective alkali metal or alkaline earth metal base is ;; added to neutralize the fatty acid produced in the first step. Preferably, the base is the respecti~e hydroxide.
The neutralizing reaction is conducted at elevated pressurs.

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In an alternate embodiment, the C12 to C24 fatty acid soap is prepared in situ from a C12 to C24 fatty acid and the respective alkali metal or alkaline earth metal base.
Preferably, the complex grease is a lithium, barium, sodium or calcium complex grease and, most preferabl~, a lithium complex grease. For the preparation of a lithium complex grease, it is preferred that the ~att~ acid is a hydroxy fatty acid, more preferably, the fatty acid is a higher h~droxy fatty acid such as 12-hydroxybehenic acid, 12-hydroxypalmitic acid or a hydrox~stearic acid such as 9-hydroxystearic acid, 10-hydroxystearic acid or 12-hydroxystearic acid. Most preferably, the fatty acid is 12-hydroxystearic acid.
Preferably, the complexing acid is a dibasic acid and, more preferably, a C2 to C12 and, most pxeferably, a C8 to C~0 dicarboxylic acid such as azelaic acid or sebacic acid.
For the preparation of barium, caIcium and sodium complex greases, the fatty acid may be palmitic acid, margaric acid, lauric acid, myristic acid, palmitioleic acid, stearic acid, arachidic acid, myristoleic acid, oleic acid, linolenic acid, linoleic acid and mixtures thereof.
With respect to the preparation o~ a barium, ~5 calcium or sodium complex grease, the complexing acid is a monobasic acid containing less than about 7 carbon atoms per molecule such as formic a~id, acetic acid, propionic acid and valeric acid, more preferably, a mono-carboxylic acid and, most preferably, acetic ~cid.
Preferably, in the case of a lithium complex grease, the molar ratio o~ total moles of fatty acid to dibasic acid in the exchange reaction is from about ~:l to about 2:1 andl more preferably, about 3:1. Preferably, in the case of barium, calcium or sodium complex greases, the molar ratio of total moles of fatty acid to monobasic acid in the exchange reaction is from about 4-1 to about 2~

2:1. For the lithium complex grease/ the exchange reaction is preferably conducted at a temperature of from about 85 to about 100C and, more preferably, about 85C.
Preferably, the amount of lithium, sodium, barium or calcium base added in the neutralization step is approximately equivalent to the amount of complexing acid used in the exchange step. Preferably, in the case of lithium complex greases, the neutrali~ation reaction is conducted at a temperature from about 190 to about 220C
and, more preferably, at about 205C and at a pressure of -from about 85 to about 120 psi and, more preferably about 85 psi.
i By utilizing the above process, complex greases and, in particular, lithium complex greases, having consistently high dropping points, good mechanical stabilities and good grease yields are obtained. Further, no dehydration step is required during the exchange reaction provided the preformed soapQis used.
These and other advantages of the instant invention may be more fully and completely understood by the following description of a preferred embodiment of the invention.
Description of the Preferred ~mbodLment The process disclosed herein may be employed to prepare alkali metal or alkaline earth metal complex greases. Pxeferably/ the method is used to prepare a lithium, barium, calcium or sodium complex grease and, most preferably/ a lithium complex grease.
The alakli metal or alkaline earth metal fatty acid soaps suitable as precursors to the respectiv~ alkali metal or alkaline earth metal complex soap may be any which is known in the art. These fatty acids from which these soaps are made may be fatty acids having from about 12 to about 24 carbon atoms and, more preferably, from about 16 to about 22 carbon atoms. The fatty acid may also comprise minor proportions of poly-unsaturated fatty ,jj ~
~ _ 7 _ 20~
, acids. For the preparation of lithium complex greases, it : is preferred that the fatty acid is a hydroxy fatty acid and, more preferably, a higher hydroxy fatty acid such as 12-hydroxybehenic acid, 12-hydroxypalmitic acid or a hydroxyste~ric acid such as 9~hydroxystearic acid, 10-hydroxystearic acid or 12-hydroxystearic acid. Most preferably, the fatty acid is a hydroxystearic acid such " as 12-hydroxystearic acid.
For the preparation of barium, calcium and sodium complex greases, the fatty acid may be-palmitic acid, margaric acid, lauric acid, myristic acid, ~ palmitioleic acid, stearic acid, arzchidic acid, :; myristoleic acid, oleic acid, linolenic acid, linoleic '~; acid and mixtures thereof.
The complexing acid used in preparing the lithium complex greases of this invention are known to ` those skilled in the art. These are dibasic acids and, more preferably, dicarboxylic acids which have from about `; 2 to about 12 and, more preferably, from about 8 to about 10 caxbon atoms. Examples of such acids include oxalic, ~ malonic, succinic, glutaric, adipic, suberic, pimelic, Y azelaic, dodecanedioic and sebacic acids. Azelaic acid and also sebacic acid are particularly preferred.
The complexing a¢id used in preparing the barium, calcium or sodium complex greases of this invention are known to those skilled in the art. These `~ are monobasic acids. Preferably, the complexing acid is a monocarboxylic acid containing less than about 7 carbon ~; atoms per molecule such as formic acid, acetic acid, propionic acid and valeric acid. Acetic acid is ~ ~ particularly preferred.
r' The lubricating oil base that is used in preparing the grease compositions of this invention may be y~ any of those conventionally used in the art. "Base oil"
herein means a lubricating fluid to which a thickener and, optionally, additives are added to produce a grease .
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- 8 - 2~ 6 composition. A base oil in general can comprise one or more lubricating oils and, optionally, asphaltic petroleum.
In particular, the compositions of the invention are ef~ective with any petroleum-based lubricating base oil, for example, naphthenic oil, solvent-refined paraffinic oil, hydrotreated oil, or a poly-alpha-olefin synthetic oil, as well as synthetic oils, such as alkylene polymers and polysiloxanes and alkylbenzenes.
Dicarboxylic acid esters, ester-type oils, or liquid esters of phosphorous acids, may be used as post-addition oils after the soap has been formed.
Hydrotreated oils are lubricating oils prepared with a blend of one or more vacuum distillate lubricating oil fractions and deasphalted residuum by catalytic treatment at elevated temperatures in the presence o~
hydrogen. The term ~hydrotreating~' includes hydrofinishing and hydrocracking, which is a more severe process than hydrofinishing. As applied particularly to lubricating oils the term "hydrotreating" encompasses a process employing a catalyst having ring scission activity. The process saturates aLomatiC compounds and selectively cracks the resulting condensed naphthenes to ~orm single-ring alkyl naphthenes, yielding an oil substantially free of aromatics and having a high proportion of paraffins. The resulting lubricating oils have a low soap solvency, as do poly-alpha-ole~in synthetic oils and, when incorporated into grease formulations as the major oil component, they produce a grease with high, i.e. poor, oil separation. In view of ; this property, i~ is surprising that the same oils produce a low oil separation grease in the compositions of the present invention. In a lubricating oil, a high Aniline point is generally an indicator o~ low soap solvency and hence of high oil bleed in a ~inished grease. The hydrotreated oils have high Aniline points, many being in - 9 - Z04~

excess of 110C, yet in the compositions o'f the present invention they produce greases having low oil separation and good yield. Indeed, thè compositions of the invention are capable of giving a surprising low-bleed grease even when the base oil blend has an Aniline point above 110C
and up to about 140C.
According to the present inve~tion, a preformed fatty acid soap, namely the alkali metal or alkaline earth metal soap of a fatty acid described above, is dispersed ln at least a portion of the base oil. In the case of a lithium complex grease, the base oil is at a temperature of from about 80 to about 110C and, more preferably from about 85 to about 90~. The mixture is agitated to disperse the fatty acid soap in ~he base oil.
In an alternate embodiment, the fatty acid ~oap may be made in situ. According to this embodiment, the fatty acid is dissolved in at least a portion of the base oil. The mixture is heated, preferably to about 85C with agitation. A base is added to this mixture and allowed to react to produce the corresponding fatty acid soap. For the production of a lithium complex grease, the base is a l.ithium base, preferably lithium hydroxideO Similarly, for the production of barium, calcium and sodium greases, it is preferred to use the respective hydroxide as the base. Preferably, a slight excess amount of the ba~e is added. It is preferred to raise the temperature of the mixture of lubricating oil and fatty acid soap to a range of from about 140 to about 170C and, more preferably, to about 150C to bring about a substantial dehydration of the mixture. Preferably, greater than about 99.9% of the water is removed prior to proceeding to the addition of the complexing acid.
Subsequent to the addition of the fatty acid soap to the base oil, or to the in situ formation of the fatty acid soap, a complexing amount of a complexing acid is added to the mixture. Preferably, prior to the - 10 - 204~96 /
addition of the complexing acid, the mixture has been brought to a temperature of from about 85 to about 100C
and, more preferably, about 85C. The complexing acid is added slowly to the mixing vessel and the reaction is ~ 5 all~wed to proceed. Preferably, the reaction occurs at a ; temperature of from about 85 to about 100C and, more preferably, at about 85C. The reaction may proceed in an ~i open kettle at atmospheric pressure. The reaction may i proceed to completion in about 25 minutes depending, inter alia, upon the size of the reaction vessel.
` As stated above, a complexing amount of the complexing acid is added to the mixture of base oil and fatty acid soap. The complexing acid reacts in an exchange reaction with the fatty acid soap to produce a soap complex and a fatty acid. The relative amount of complexing acid which is added is adjusted so that the reaction proceeds to produce the desired grease complex.
The amount of complexing acid which may be utilized varies within fairly broad ranges. If too much complexing acid is utili~ed, then a less lipophilic soap is obtained.
These soaps result in greases having higher dropping points and lower grease yields. Accordingly, the proportion of fatty acid to complexing acid is adjusted to compensate for the degree of soap solvency in the base oil or the mixture of base oils which is employed to obtain fairly high dropping points and good grease yields.
Preferably, in preparing a lithium complex grease, the molar ratio of fatty acid to complexing acid employed in the exchange reaction is from about~ 4-1 to about 2:1 and, more preferably about 3:1. In the case of barium, calcium and sodium greases, the ratio is preferably from about 4:1 to about 2:1.
As a result of the exchange reaction, the reaction mixture contains liberated fatty acid. This fatty acid is neutralized in the second step of the instant process by the addition of the respective alkali .

1 1 - Z~ 6 metal or alXaline earth metal base which, preferably, is in the form of a hydroxide which is added as a slurry in water. Accordingly, a small amount of water is added to the mixture in addition to the base. The alkali metal or alkaline earth metal component of the base will vary depending upon the complex grease which is to be prepared.
In the case of the preparation of a lithium complex grease, a lithium base is used which, preferably, is lithium hydroxide. The fatty acid is preferably neutralized with an amount of base which is equi~alent to the amount of complexing acid utilized in the exchange reaction.
Preferably, the neutralization reaction occurs at elevated pressures. According to this embodiment, subse~uent ~o the exchange reaction, the mixture is added to a closed pressuriæed contactor. Since closed pressurized contactors typically have limited volume, it is preferred that only a portion of the base oil is used as a solvent for the purpose of the exchange and neutralization reactions. The remaining portion of the base oil is preferably added subsequent to the ~ormation of the grease. With respect to the preparation of lithium complex greases, preférably from about 30 to about 80 wt.~
of the oil, based on the total weight of the base oil, is used as the solvent. More preferably, from about 60 to about 70 wt.% of the oil is used. The neutralization - reaction preferably occurs at a pressllre from about 85 to about 120 and, more preferably, at about 85 psi.
Preferably, the reaction occurs at a temperature of from about 190 to about 220C and, more preferably, at about ~ 205C.
; Subsequent to the completion of the neutralization reaction, the contactor is depressurized slowly to atmospheric pressure. The grease in the contactor may then be cooled to below about 185C by the addition of the remainder of the base oil. The batch is 2~96 . , then gradually discharged to a finishing kettle as the rest of the base oil is added to the contactor.
Milling of the grease mixture is done by ` conventional methods r for example passing the material through a colloid mill at a clearance of 0.08 mm. In addition, various additives may be introduced into the final composition if desired, as for ex~mple, extreme pressure (EP) agents, oxidation inhibitors, rust inhibitors, dyes, fillers and the like.
The extreme pressure lEP) properties of the grease composition can be raised with conventional EP
additives well-known to those skilled in the art. For example any of several metalic compounds or phosphorous ~ compounds, for example precipitated calcium carbonate may `~ 15 be used. If it is desired to incorporate an antioxidant, well-known antioxidant materials can be used. For example zinc dialkyl dithiocarbamate, alkyldiphenylamines and hindered phenols may be used.
To measure the properties of greases and to predict their performance in service in different end uses, the American Society for Testing Materials ~ASTM) has adopted a variety of standardized tests. The penetration tests measuring grease consistency when unworked and worked, measured after 60 strokes, in a standard grease worker (ASTM D-217) have been used for many years. In addition, the penetration is measured after 10,000 or 100,000 strokes to det~rmine the mechanical stability of the grease under relatively low shear conditions.
The grease stability at higher shear is determined by a Roll Stability Test (ASTM D-1831) wherein a sample of grease is worked in a standard cylinder ~; containing a roller and its penetration change is measured after two hours.
The invention will be further understood by the following examples which are not to be construed as a - 13 - 2 ~ ~2 1 ~ ~

limitation of the inv~ntion. Those skilled in the art will appreciate that other and further embodiments are obvious and within the spirit and scope of this invention from the teachings of the present examples taken with the accompanying specification.

249~5 g of the preformed lithium 12-hydroxystearate soap was dispersed in the base oil blend of 336.3 g of cylinder stock and 1345.2 g of 650N
hydrotreated oil (Aniline Point = 124C) being circulated in an open 4.5 L grease contactor while raising the temperature of the contents to and maintaining the contents at 100C. 81.25 g of azelaic acid was added to the mixture in the contactor and the reaction was allowed to proceed for 20 minutes at 100C.
37.75 g of lithium hydroxide monohydrate and 4 g of water were quickly added to the mixture and the contactor was closed. The temperature of the contents of the contactor was raised to and maintained at 205-216C
for 20 ~minutes. The contactor pressure was vented periodically to maintain the vessel's pressure at the desired'689.5 kPa (100 psi) during the hold-up period at 205-216C.
The heat was turned off and the steam was carefully vented to reduce the pressure to ambient withir.
5-10 minutes and the contactor was then opened. The mixture was cooled by the gradual a~ddition of 90 g of cylinder stock and 360 g of 650N hydrotreated oil so that the temperature of the contactor contents was lowered below 185C within 20-30 minutes. The grease was milled and finished in the normal manner. The grease characteristics were as set out in Table 1.
The lit,hium 12-hydroxystearate utilized in this Example was a preformed soap containing 2.3% ~ithium. It - 14 - 2 ~ 96 is commercially available from Witco Chemical, Organics Division.
The azelaic acid which was used in this Example was Emerox 1110, which is a C9 dibasic acid 79% pure with an average molecular weight o~ 188. It is commercially available from Henkel Canada Ltd.

E~aMPLE 2 A further 100 g of cylinder stock and 400 g of 650N hydrotreated oil were added to the product of Exa~ple 1. The mixture was milled and finished in the normal manner to produce an NLGI number 2 grease. The results are also shown in Table 1.
E~aMPLE 3 Example 1 was repeated with the exception that the first step reaction was carried out at 85C instead of 100C for 40 minutes. The resultant grease characteristics were very similar to those of Example l of Table 1.

~XAMPLE 4: Comparative Example Example 1 was repeated with the exception that the first stage reaction was omitted. The grease was prepared in a one step process. All of the components, which are set out below, were added to the base oil which was being circulated in a grease contac~or:
Lithium 12~hydroxystearate107 g Azelaic acid 67.5 g Lithium hydroxide monohydrate30.8 g Cylinder Stock 388.9 g 650N 1555.8 g Nater 4.0 g The contactor was closed and the temperature of the contents was raised and maintained at 205-216C. The rest of the pxocedure was the same as for Example 1. The grease yield and dropping point were signi~icantly lower.

EXAMPL~ 5: Comparative Example :
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199.9 g of 12-hydroxystearate acid and 66.6 g of azelaic acid were dispersed in the base oil blend of 345 g cylinder stock and 1380.5 g of 650N hydrotreated oil (Aniline Point = 124C) being circulated in an open 4.5 L
grease contactor and the contents were allowed to mix for ~; 20 minutes. 58 g of likhium hydroxide monohydrate and 4 g of water were added, the contactor was closed and the temperature of the contents was raised to and maintained at 205-216C for 20 minutes. The rest of the procedure was the same as for Example 1. The grease yield and, in . particular, the dropping point were lower indicating that the complex soap did not form.
.

s~ 108.9 g of preformed lithium 12-hydroxystearate 15 was dispersed in 168.3 g of cylinder stock and 673.4 g of 65ON oil in an open kettle (Hobart Mixer). The temperature of the mixture was raised to and maintained at 100C. 32.5 g of azelaic acid was added and the reaction was allowed to proceed for 25 minutes. 16.9 g of lithium hydroxide monohydrate was added as a slurry with 5 g of water which was added gradually to avoid severe foaming.
`~ The temperature of the mixture was then raised to and maintained at 205C for 25 minutes. A blend of 100 g of 'J' cylinder stock and 400 g of 650N oil was gradually added 25 to cool down the batch below 185C within 20-30 minutes.
The grease was milled and finished in the normal manner.
The gréase charac~eristics are set out in Table 1.
"
~A~L~L~ 7 ~ 505 g of cylinder stock, 700 g 650N oil, 292.5 : 30 g 12-hydroxystearic acid and 97.5 g azelaic acid were charged to an open kektle (Hobart Mixer). The mix~ure was stirred whils its temperature was raised to 82C at which point 84.9 g of lithium hydroxide monohydrate and 50 g of water were added. The temperature of the mixture was then ,,:
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raised to and maintained at 216C ~or one hour. The mixture was cooled down by the gradual addition of 1320 g of 650N oil over a period of one hour. The grease was milled and finished in the normal manner. The grease characteristics are set out n Table 1.

EXANP~ES 8-11 Example 1 was repeated with the exception that the first step reaction was carried out at 85C instead of lOOQC for 40 minutes and an additional fatty acid, as shown in Table 2, was added to the reactants to improve its compatibility with the oil blend used and increase the grease yield. As shown in Table 3, all of the acids were effective in producing higher grease yields.
T-ll fatty acid is a partially hydrb~enated material containing about 40% unsaturated fatty acids and has an average molecular weight of about 274. It is commercially available from Proctor and Gamble Company of Canada Ltd.
Palmitic acid, Century 16~5, is a C16 acid 86%
pure with an average molecular weight of about 257. It is commercially available from Union Camp Corporation.
Behenic acid, Crodacid PG3440, is a C22 acid with an average molecular weight of about 340. It is commercially available from Croda C~nada Ltd.

E~ample 9 was repeated with the exceptio~ that the base oil blend composition was changed as shown in Table 4. 160N is a hydrotreated oil (Aniline Point -109C). PA~ 40 is a polyalphaolefin with a viscosity of 40.3 cSt at 100C and is commerically available from Uniroyal Chemical Co. Alkylate H230L is a linear alkyl benzene with an average molecular weight of 335 and is commercially available from Nonsanto Industrial Chemicals Co. The results are set out in Table 5.

2ai~ 96 E~A~PL~5 15 AND 16 The grease of Example 15 was manufactured according to the procedure described in United States Patent No. 3,791,973. The grease of Example 16 was manufactured by the applicant according to the procedure of Example 3 herein. As shown in Table 6, the grease made by the two-step process had improved yield (lower soap content) than that made by the conventional process.

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Claims (33)

1. A process for preparing an alkali metal or alkaline earth metal complex soap for use in the preparation of an alkaline metal or alkaline earth metal complex grease which comprises reacting an alkali metal or alkaline earth metal soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap in the presence of a base oil with a complexing amount of a complexing acid to produce the respective alkali metal or alkaline earth metal complex soap and fatty acid, and subsequently reacting said fatty acid with a neutralizing amount of the respective alkali metal or alkaline earth metal base.

2. The process of claim 1 wherein the alkali metal or alkaline earth metal is sodium, barium or calcium.

3. The process of claim 1 wherein said alkali metal or alkaline earth metal is lithium.

4. The process of claim 3 wherein said complexing acid is a dibasic acid.

5. The process of claim 4 wherein said dibasic acid is a dicarboxylic acid having from about 2 to about 12 carbon atoms.

6. The process of claim 5 wherein said dicarboxylic acid, azaelic or sebacic acid.

7. The process of claim 2 wherein said complexing acid is a monocarboxylic acid having less than about 7 carbon atoms.

8. The process of claim 7 wherein said monocarboxylic acid is acetic acid.

9. The process of claim 1, 5 or 7 wherein said alkali metal or alkaline earth metal soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap has from about 12 to about 24 carbon atoms.

10. The process of claim 6 or 8 wherein said alkali metal or alkaline earth metal soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap has from about 16 to about 22 carbon atoms.

11. The process of claim 5 wherein said alkali metal or alkaline earth metal soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap is prepared from a hydroxy fatty acid.

12. The process of claim 11 wherein said hydroxy fatty acid is a higher hydroxy fatty acid.

13. The process of claim 5 or 12 wherein said alkali metal or alkaline earth metal soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap is prepared from a hydroxystearic acid.

14. The process of claim 1 wherein the ratio of fatty acid soap to complexing acid is from about 4:1 to about 2:1.

15. The process of claim 3, 5 or 12 wherein the ratio of said fatty acid soap to complexing acid is about 3:1.

16. The process of claim 1 or 14 wherein the amount of base which is reacted with said fatty acid is equivalent to the amount of complexing acid which is reacted with said soap.

17. The process of claim 1 wherein the base is a hydroxide.

18. The process of claim 1 wherein said alkali metal or alkaline earth metal soap suitable as a precursor to the respective alkali metal or alkaline earth metal complex soap is formed in situ.

19. The process of claim 1 wherein said fatty acid soap is reacted with said complexing acid at a temperature from about 85° to about 100°C.

20. The process of claim 1 or 19 wherein said neutralization reaction occurs at a temperature of about 190° to about 220°C and at a pressure from about 85 to about 120 psi.

21. The process of claim 1 wherein a thickening amount of the alkali metal or alkaline earth metal complex soap of claim l.is added to a base oil to prepare a grease.

22. A grease when the complex soap is prepared by the process of claim 21.

23. The grease of claim 22 further comprising an extreme pressure additive.

24. The grease of claim 22 further comprising an antioxidant.

25. A process for preparing a lithium complex soap for use in the preparing of a lithium complex grease comprising the steps of:
(1) reacting a fatty acid soap suitable as a precursor to lithium complex soap in the presence of a base oil with a complexing amount of a dicarboxylic acid having from about 2 to about 12 carbon atoms to produce a complex soap and a fatty acid; and, (2) reacting said fatty acid with a neutralizing amount of a lithium base, the ratio of said fatty acid soap to said complexing acid being from abut 4:1 to about 2:1 and the amount of said base which is reacted with said fatty acid is equivalent to the amount of complexing acid which is reacted with said soap.

26. The process of claim 25 wherein said fatty acid soap has from about 12 to about 22 carbon atoms.

27. The process of claim 26 wherein said fatty acid soap is made from a hydroxystearic acid and said complexing acid is azaelic acid or sebacic acid.

28. The process of claim 27 wherein said base is lithium hydroxide.

29. The process of claim 28 wherein the reaction of the fatty acid soap and the complexing acid occurs at a temperature from about 85° to about 100°C.

30. The process of claim 29 wherein said neutralization reaction occurs at a temperature from about 190° to about 220°C and at a pressure from about 85 to about 120 psi.

31. The process of claim 25 wherein said fatty acid soap is made in situ by reacting a higher hydroxy fatty acid with a lithium base.

32. The process of claim 31 wherein said mixture of base oil and fatty acid soap is dehydrated prior to reacting said fatty acid soap with said complexing acid.

33. A grease when the complex soap prepared by the process of claim 30, 31 or 32.