U.S. patent application number 12/106358 was filed with the patent office on 2009-10-22 for overbased metal carboxylate precursor and process for making.
This patent application is currently assigned to OMG AMERICAS, INC.. Invention is credited to Michael Allen AMSLER, Hugh Wynn GIBBS, Ruiming ZHANG.
Application Number | 20090264327 12/106358 |
Document ID | / |
Family ID | 41201617 |
Filed Date | 2009-10-22 |
United States Patent
Application |
20090264327 |
Kind Code |
A1 |
ZHANG; Ruiming ; et
al. |
October 22, 2009 |
OVERBASED METAL CARBOXYLATE PRECURSOR AND PROCESS FOR MAKING
Abstract
Shelf stable, flowable liquids of overbased alkaline earth metal
salts 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 overbased alkaline earth metal salts
has an alkaline earth metal content of at least about 14.5% and a
non-volatile matter content of at least about 95%.
Inventors: |
ZHANG; Ruiming; (Belle Mead,
NJ) ; AMSLER; Michael Allen; (Titusville, PA)
; GIBBS; Hugh Wynn; (Knutsford, GB) |
Correspondence
Address: |
HAHN LOESER & PARKS, LLP
One GOJO Plaza, Suite 300
AKRON
OH
44311-1076
US
|
Assignee: |
OMG AMERICAS, INC.
Westlake
OH
|
Family ID: |
41201617 |
Appl. No.: |
12/106358 |
Filed: |
April 21, 2008 |
Current U.S.
Class: |
508/460 |
Current CPC
Class: |
C10M 2207/26 20130101;
C10M 2203/10 20130101; C10M 2207/022 20130101; C10M 159/20
20130101; C10N 2070/02 20200501; C10M 2207/021 20130101; C10M
2207/26 20130101; C10N 2010/04 20130101; C10M 2207/26 20130101;
C10N 2010/04 20130101 |
Class at
Publication: |
508/460 |
International
Class: |
C10M 105/34 20060101
C10M105/34 |
Claims
1. A shelf stable, flowable liquid of an overbased alkaline earth
metal salt of a fatty acid, the liquid comprising: at least one
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, wherein the alkaline earth metal salt has an
alkaline earth metal content of at least about 14.5% and a
non-volatile matter content of at least about 95%.
2. The liquid of claim 1, wherein the fatty acid is a
C.sub.12-C.sub.22 fatty acid.
3. The liquid of claim 2, wherein the fatty acid is oleic acid.
4. The liquid 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.
5. The liquid of claim 1, wherein the overbased alkaline earth
metal salt is calcium oleate.
6. The liquid of claim 1, wherein the alcohol is an aliphatic
alcohol of at least 14 carbon atoms.
7. The liquid of claim 1, wherein the polyol is a glycol or a
glycol ether selected from the group consisting of diethylene
glycol monobutyl ether, propylene glycol, hexylene glycol,
triethylene glycol, dipropylene glycol, diethylene glycol
monomethyl ether, ethylene glycol monobutyl ether, and mixtures
thereof.
8. A method for preparing a shelf stable, flowable liquid of an
overbased alkaline earth metal salt of a fatty acid, the method
comprising the steps of: (a) preparing a precursor mixture
comprising a carboxylic acid, wherein the carboxylic acid is a
fatty acid; at least one hydrocarbon liquid; 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
precursor mixture; (c) heating the alkaline earth metal carboxylate
precursor mixture; (d) adding an additional amount of an alkaline
earth metal base to the alkaline earth metal carboxylate precursor
mixture; (e) carbonating the precursor mixture to neutrality; (f)
filtering the precursor mixture; and (g) distilling the precursor
mixture until an alkaline earth metal content of at least about
14.5% and a non-volatile matter content of at least about 95% is
achieved.
9. The method of claim 8, wherein the fatty acid is a
C.sub.12-C.sub.22 fatty acid.
10. The method of claim 9, wherein the fatty acid is oleic
acid.
11. The method of claim 8, wherein the alkaline earth metal is
selected from the group consisting of calcium, barium, magnesium
and strontium.
12. The method of claim 8, wherein the alkaline earth metal
carboxylate precursor mixture includes calcium oleate and calcium
carbonate.
13. The method of claim 8, wherein the alcohol is an aliphatic
alcohol of at least 12 carbon atoms.
14. The method of claim 8, wherein the polyol is a glycol or a
glycol ether selected from the group consisting of diethylene
glycol monobutyl ether, propylene glycol, hexylene glycol,
triethylene glycol, dipropylene glycol, diethylene glycol
monomethyl ether, ethylene glycol monobutyl ether, and mixtures
thereof.
15. The method of claim 8, wherein the precursor mixture is
distilled with vacuum stripping.
Description
[0001] The invention relates to a shelf stable, flowable liquid of
an alkaline earth metal salt of a fatty acid and a process for
preparing the liquid. More particularly, the invention relates to a
shelf stable, flowable precursor of an overbased alkaline earth
metal carboxylate and a process for preparing the precursor. Even
more particularly, the invention relates to a shelf stable,
flowable precursor of an overbased calcium carboxylate and a
process for preparing the precursor.
BACKGROUND OF THE INVENTION
[0002] The preparation of overbased calcium or barium salts of
carboxylic acids, alkyl phenols, and sulfonic acids are disclosed
in the following U.S. Pat. Nos. 2,616,904; 2,760,970; 2,767,164;
2,798,852; 2,802,816; 3,027,325; 3,031,284; 3,342,733; 3,533,975;
3,773,664; and 3,779,922. The use of these overbased metal salts in
the halogen-containing organic polymer is described in the
following U.S. Pat. Nos. 4,159,973; 4,252,698; and 3,194,823. The
use of overbased barium salt in stabilizer formulations has
increased during recent years. This is due, in the main, to the
fact that overbased barium salts possess performance advantages
over the neutral barium salts. The performance advantages
associated with overbased barium salts are low plate-out, excellent
color hold, good long-term heat stability performance, good
compatibility with the stabilizer components, etc. Unfortunately,
most of the overbased barium salts are dark in color and, while
these dark colored overbased barium salts are effective stabilizers
for halogen-containing organic polymer, their dark color results in
the discoloration of the end product. This feature essentially
prohibits the use of dark colored overbased barium salts in
applications where a light colored polymer product is desired.
[0003] According to the teachings of U.S. Pat. No. 4,665,117, light
colored alkali or alkaline earth metal salts are prepared where
alkyl phenol is used as a promoter. However, alkyl phenol is also a
major cause for the development of color in the final product. This
problem is overcome by the use of propylene oxide which displaces
the hydrogen of the phenolic hydroxyl group and thereby restricts
the formation of colored species. However, there are disadvantages
associated with this approach, principally due to the toxic nature
of propylene oxide. Propylene oxide is classified as a possible
carcinogen and laboratory animal inhalation studies have shown
evidence of a link to cancer. Propylene oxide is also listed as a
severe eye irritant, and prolonged exposure to propylene oxide
vapors may result in permanent damage to the eye. Furthermore,
propylene oxide is extremely flammable and explosive in nature
under certain conditions. Propylene oxide boils at 94.degree. F.
and flashes at -20.degree. F. As a result, extreme precautions are
required to handle propylene oxide at the plant site. Special
storage equipment is required for propylene oxide and other safety
features are necessary. U.S. Pat. No. 4,665,117 describes the use
of propylene oxide at 150.degree. C. At this temperature, propylene
oxide will be in the gaseous phase. Under these operating
conditions, more than stoichiometric amounts of propylene oxide are
required to carry the reaction to completion because propylene
oxide will escape from the reaction mixture and this requires
additional handling of the excess propylene oxide.
[0004] Liquids of overbased metal carboxylate salts are also used
in the preparation of greases. In particular, grease manufacturing
includes a multi-step process and numerous additives to provide
property enhancements which present an increasing challenge to the
specialty, food-grade and bio-based grease formulators. The
resulting grease performance is also strongly dependent upon the
processing conditions such as temperature, pressure, residence
times and saponification stoichiometry.
[0005] Thixotropic greases or grease-like overbased metal
carboxylate or other overbased metal-containing compositions having
corrosion-inhibiting properties, and having utility for a variety
of uses such as, for instance, in automobile and truck body
undercoatings, and for various other purposes, are known to the
art. Such greases or grease-like compositions have gone into quite
widespread use either as such, or admixed with other ingredients to
produce compositions for use in a variety of environments, and,
generally speaking, they are characterized by reasonably good
extreme pressure and antiwear properties, high dropping points,
reasonably good resistance to mechanical breakdown, salt spray and
water-corrosion resistance, thermal stability at high temperatures,
and other desirable properties.
[0006] Whether the liquid of an overbased metal carboxylate salt is
utilized in halogen-containing organic polymers or in the
preparation of greases, volatile components, including volatile
organic compounds (VOCs), of the overbased metal carboxylate should
be minimized for health, safety and environmental reasons.
[0007] Notwithstanding the state of the art as described herein,
there is a need for further improvements in preparing overbased
alkaline earth metal salts of fatty acids for use in
halogen-containing organic polymers and in the preparation of
greases, wherein the overbased alkaline earth metal salts have
substantially reduced levels of volatile components within the
final product.
SUMMARY OF THE INVENTION
[0008] In general, one aspect of the invention is to provide a
shelf stable liquid of an overbased alkaline earth metal salt of a
fatty acid, wherein the alkaline earth metal content is at least
about 14.5% and the non-volatile matter content is at least about
95%.
[0009] In yet another aspect of the invention, a shelf stable,
flowable liquid of an overbased alkaline earth metal salt of a
fatty acid is provided. The liquid includes at least one
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, wherein the alkaline earth metal salt has an
alkaline earth metal content of at least about 14.5% and a
non-volatile matter content of at least about 95%.
[0010] In another aspect of the invention, a method for preparing a
shelf stable, flowable liquid of an overbased alkaline earth metal
salt of a fatty acid is provided, the method includes the steps
of:
[0011] (a) preparing a precursor mixture comprising a carboxylic
acid, wherein the carboxylic acid is a fatty acid; at least one
hydrocarbon liquid; a polyol; and an alcohol, wherein the alcohol
has at least 8 carbon atoms;
[0012] (b) neutralizing the carboxylic acid with an initial amount
of alkaline earth metal base to form an alkaline earth metal
carboxylate precursor mixture;
[0013] (c) heating the alkaline earth metal carboxylate precursor
mixture;
[0014] (d) adding an additional amount of an alkaline earth metal
base to the alkaline earth metal carboxylate precursor mixture;
[0015] (e) carbonating the precursor mixture to neutrality;
[0016] (f) filtering the precursor mixture; and
[0017] (g) distilling the precursor mixture until an alkaline earth
metal content of at least about 14.5% and a non-volatile matter
content of at least about 95% is achieved.
[0018] These and other advantages and novel features of the present
invention, as well as details of an illustrated embodiment thereof,
will be more fully understood from the following description.
BRIEF DESCRIPTION OF THE DRAWING
[0019] FIG. 1 is a graph of a thermogravimetric analysis of a shelf
stable, flowable liquid of an overbased alkaline earth metal salt
of a fatty acid in one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In one embodiment of invention, a shelf stable, flowable
liquid of an overbased alkaline earth metal salt of a fatty acid
prepared from a precursor includes an alkaline earth metal
carbonate, an alkaline earth metal carboxylate of a fatty acid, a
liquid hydrocarbon, and an alcohol having at least 8 carbon atoms,
with the liquid having alkaline earth metal content is at least
about 14.5% and the non-volatile matter content is at least about
95%.
[0021] The alkaline earth metal of the salt of the overbased
alkaline earth metal salt of the fatty acid precursor may be
selected from the group consisting of calcium, barium, magnesium
and strontium. These metals may be derived from metal oxides and
hydroxides, and in some instances, metal sulfides and
hydrosulfides. For example, the alkaline earth metal salt may
include a calcium carboxylate.
[0022] The carboxylic acid portion of the overbased alkaline earth
metal salt precursor, may include fatty acids, including
C.sub.8-C.sub.30 saturated, unsaturated carboxylic acids of 8 to 30
carbon atoms, either alone or in combination with each other, or
reactive equivalents of carboxylic acids. Examples of useful
carboxylic acids and fatty acids include but are not limited to
caprylic acid, capric acid, lauric acid, myristic acid, myristoleic
acid, 2-ethylhexanoic acid, decanoic acid, dodecanoic acid,
pentadecanoic acid, palmitic acid, palmitoleic acid, stearic acid,
12-hydroxystearic acid, oleic acid, ricinoleic acid, linoleic acid,
linoleic acid, arachidic acid, gadoleic acid, behenic acid, erucic
acid, and mixtures of any of these acids.
[0023] The shelf stable, flowable liquid of an overbased alkaline
earth metal salt of the fatty acid precursor of the present
invention may also include an alcohol that promotes the formation
of the overbased alkaline earth metal carboxylate. The alcohol
includes aliphatic alcohols that contain at least 8 carbon atoms.
In one example, an aliphatic alcohol having a range from about 8 to
about 18 carbon atoms may be used. Examples of such aliphatic
alcohols include isodecanol, dodecanol, octanol, tridecanol,
tetradecanol or mixtures thereof. It has been found that when a
higher aliphatic alcohol is employed in making the overbased
product, phenol may be excluded from the reaction as a
promoter.
[0024] The shelf stable liquid of an overbased alkaline earth metal
salt of the fatty acid precursor of the present invention may also
include a polyol. The polyol can be a glycol or glycol ether. The
glycol or glycol ether may be selected from the group consisting of
diethylene glycol monobutyl ether (butyl Carbitol.RTM., triethylene
glycol, hexylene glycol, propylene glycol, dipropylene glycol,
diethylene glycol monomethyl ether, ethylene glycol monobutyl
ether, and mixtures thereof.
[0025] In another embodiment of the present invention, a liquid
base oil may also be employed for preparing the overbased precursor
materials. The base oil can be a hydrocarbon liquid that generally
includes any hydrocarbon diluent. Most generally, the liquid
hydrocarbon is selected from the group of hydrocarbon oils, mineral
spirits, non-aromatic hydrocarbons and polyalphaolefins (PAOs). In
one embodiment of the invention, suitable hydrocarbon liquids
include SHELLSOL.TM. D70 and D80 commercially available from Shell
Chemical. In yet another embodiment, the PAOs are utilized, either
alone or in combination with other liquid hydrocarbons, as suitable
liquid hydrocarbons for preparing the overbased precursor material
since they have flexible alkyl branching groups on every other
carbon of their polymer backbone chain. These alkyl groups, which
can shape themselves in numerous conformations, make it very
difficult for the polymer molecules to line themselves up
side-by-side in an orderly way. Furthermore, many PAOs are
relatively stable at higher temperatures and typically have a
tendency not to crystallize or solidify at lower temperatures since
they are able to remain as oily, viscous liquids.
[0026] In yet another embodiment of the invention, the process for
preparing a shelf stable liquid of an overbased alkaline earth
metal salt of a fatty acid precursor includes reacting an alkaline
earth metal base and a fatty acid with an equivalent ratio of metal
base to the fatty acid being greater than 1:1 in the presence of a
at least one liquid hydrocarbon, an alcohol, and a glycol ether.
The mixture may be acidified and carbonated to produce amorphous
alkaline earth metal carbonate within the mixture. During
carbonation, a dispersion may be added containing alkaline earth
metal base, liquid hydrocarbon and an alcohol having at least 8
carbon atoms in relative amounts at a controlled rate of base
addition to produce a stable haze free liquid reaction product.
During the reaction, water is removed from the reaction product to
produce a shelf stable, flowable liquid overbased alkaline earth
metal salt. Generally, the entire process may be conducted in the
absence of free oxygen and, for this purpose, an atmosphere of
nitrogen may be used.
[0027] Throughout this specification and claims, the term "basic"
or "overbased" as applied to the alkaline earth metal salts is used
to refer to metal compositions wherein the ratio of total metal
contained therein to the fatty acid moieties is greater than the
stoichiometric ratio of the neutral metal salt. That is, the number
of metal equivalents is greater than the number of equivalents of
the fatty acid. In some instances, the degree to which excess metal
is found in the basic metal salt is described in terms of a "metal
ratio". Metal ratio as used herein indicates the ratio of total
alkaline earth metal in the oil-soluble composition to the number
of equivalents of the fatty acid or organic moiety. The basic metal
salts often have been referred to in the art as "overbased" or
"superbased" to indicate the presence of an excess of the basic
component.
[0028] It has been found important during carbonation to add the
dispersion of metal base, liquid hydrocarbon and aliphatic alcohol
in relative amounts at a controlled rate to produce the stable
reaction product. There are a number of reasons which are believed
to contribute to the formation of a stable liquid which is then
filterable to remove impurities and byproducts of the reaction. It
has been determined that by the continuous addition of the
dispersion or slurry of base during carbonation, such results are
achievable. It is believed that the metal base slurry prevents the
formation of undesirable calcium carbonate crystals or byproducts
in the desired overbased metal salt. These undesirable moieties
prevent the formation of stable products which are filterable.
Thus, the metal base slurry is added at a controlled rate which
does not exceed the rate of the desired product-forming reaction.
The reaction is controlled by continuous or incremental addition of
the metal base to make the calcium ions immediately available for
the desired reaction as opposed to allowing the metal base, for
example lime, to react and form a byproduct. Excessive byproduct or
lime coated with calcium carbonate is believed to render the liquid
product unalterable. Using this procedure, the pH is controlled
during the reaction so that the fatty acid is neutralized and the
pH rises to about 7-10 with the continued addition of base to
produce dissolved metal ion which reacts with CO.sub.2 during
carbonation to produce the desired product. It is believed if the
reaction rate is not controlled, and the base is not dissolved,
then solid base reacts or is coated with calcium carbonate to form
undesirable byproducts. The formation of undesirable byproducts of
the reaction renders the final product unstable and
unfilterable.
[0029] As developed above, one of the features of the method is the
step of adding during carbonation a dispersion of an alkaline earth
metal base, polyol, liquid hydrocarbon and an alcohol having at
least 8 carbon atoms at a controlled rate of base addition to
produce the stable, flowable liquid. It has been determined that
the addition of a dispersion of the base in the liquid hydrocarbon
and aliphatic alcohol protects or passivates the base, thereby
enabling the formation of a stable, flowable liquid reaction
product. By protecting or passivating the base, carbonation
proceeds to produce amorphous alkaline earth metal carbonate.
Unexpectedly, the reaction proceeds without the need to remove
water during the reaction and results in a shelf stable liquid
reaction product.
[0030] The amount of alkaline earth metal base utilized in the
preparation of basic salts is an amount which is more than one
equivalent of the base per equivalent of fatty acid or organic
moiety, and more generally, will be an amount sufficient to provide
at least three equivalents of the metal base per equivalent of the
acid. Larger amounts can be utilized to form more basic compounds,
and the amount of metal base included may be any amount up to that
amount which is no longer effective to increase the proportion of
metal in the product. When preparing the mixture, the amount of
fatty acid and the alcohol included in the mixture should be
greater than 1:1 in order to provide a basic product. More
generally, the ratio of equivalents will be at least 3:1.
[0031] The ratios of hydrocarbon oil to alcohol (dodecanol) are
about 2:1 to about 4:1 in one embodiment of the invention. The
glycol ether may be used at about 1-15% of the final product.
[0032] The lime slurry which is added to the oleic acid in the
reaction is formulated to be a pumpable mixture with the general
composition of about 40-50% lime, about 25-40% hydrocarbon oil,
about 10-25% dodecanol, and about 0-10% propylene glycol. The
propylene glycol amount that is needed to make a pumpable slurry
increases as the percentage of lime in the slurry increases.
[0033] The process for preparing the shelf stable, flowable
overbased calcium carboxylate precursor includes the reaction of an
alkaline earth metal base and a carboxylic acid to form an alkaline
earth metal carboxylate mixture, with an equivalent ratio of metal
base to the carboxylic acid greater than 1:1 in the presence of a
liquid hydrocarbon, an aliphatic alcohol, and a glycol ether. In
one embodiment, the carboxylic acid is a fatty acid, the fatty acid
being oleic acid, the liquid hydrocarbon is SHELLSOL.TM. D80, the
alcohol is dodecanol, and the glycol ether is propylene glycol. The
mixture is acidified, through a process of carbonation, to produce
amorphous alkaline earth metal carbonate, for example calcium
carbonate. The step of carbonation involves treating the mixtures
described above with an acidic gas in the absence of free oxygen
until the titratable basicity is determined using phenolphthalein.
Generally, the titratable basicity is reduced to a base number
below about 10. The mixing and carbonation steps require no unusual
operating conditions other than the exclusion of free oxygen.
[0034] By the term "acidic gas" as used in this specification and
in the claims is meant a gas which upon reaction with water will
produce an acid. Thus, such gases as sulfur dioxide, sulfur
trioxide, carbon dioxide, carbon disulfide, hydrogen sulfide, etc.,
are exemplary of the acidic gases which are useful in the
preparation of the overbased metal carboxylates disclosed. When
carbon dioxide is used the alkaline earth carbonate is formed. When
the sulfur gases are used, the sulfate, sulfide and sulfite salts
are formed.
[0035] During carbonation, the alkaline earth metal base, polyol,
liquid hydrocarbon and alcohol may be added in relative amounts at
a controlled rate of base addition. In one embodiment of the
invention, the dry alkaline earth metal base, polyol, liquid
hydrocarbon and alcohol may be slurried to facilitate mixing during
the carbonation process. Water is removed from the reaction product
to produce a shelf stable, flowable liquid of an alkaline earth
metal salt of a fatty acid. Generally, the process be conducted in
the absence of free oxygen and, for this purpose, an atmosphere of
nitrogen is used.
[0036] During carbonation the mixture may be heated to a
temperature which is sufficient to drive off some of the water
contained in the mixture or the water generated during the reaction
of the base and the carboxylic acid can be retained during the
overbasing reactions. The treatment of the mixture with the carbon
dioxide preferably is conducted at elevated temperatures, and the
range of temperatures used for this step may be any temperature
above ambient temperature in the range from about 75.degree. C.
(about 165.degree. F.) to about 200.degree. C. (about 390.degree.
F.). Higher temperatures may be used such as 250.degree. C. (about
480.degree. F.), but there is no apparent advantage in the use of
such higher temperatures. Ordinarily, a temperature of about
80.degree. C. (about 175.degree. F.) to 150.degree. C. (about
300.degree. F.) is satisfactory.
[0037] Other features of the method include filtering the product
of the reaction to produce a shelf stable liquid precursor at a
product filtration rate of at least about 300 ml per 10 minutes. In
one embodiment of the invention, the product which is produced is
filterable to remove unwanted byproducts and enhance the shelf
stability of the overbased liquid. For example, with a Buchner
funnel under vacuum of about 25-30 inches Hg with a Whatman No. 1
filter and a diatomaceous earth filtering aid, the product is
filterable at satisfactory rates. Thus, filtration removes
undesirable impurities including silica, iron oxide and other metal
species, unreacted calcium hydroxide, calcium carbonate, and other
oxides which may contribute to lack of stability.
[0038] In another aspect of the invention, the liquid overbased
alkaline earth salt of the fatty acid precursor is believed to be a
thermodynamically stable microemulsion. The microemulsion has
micelles and a continuous phase. The micelles consist of an
alkaline earth metal carbonate and an alkaline earth metal
carboxylate of the fatty acid. The continuous phase of the
microemulsion consists of the liquid hydrocarbon and the
alcohol.
[0039] In yet another embodiment of the invention, after the
removal of water from the precursor of the alkaline earth metal
base, fatty acid, polyol, liquid hydrocarbon and alcohol, the
precursor is distilled or vacuum stripped at a temperature up to
about 165.degree. C. (about 330.degree. F.) to remove the volatile
components of the reaction product. In distillation terminology,
"stripping" refers to the removal of a volatile component from a
less volatile substance. The vacuum stripping proceeds until the
final product has a measured alkaline earth metal content of at
least about 14.5% and a non-volatile matter content of at least
about 95%.
[0040] In still yet another embodiment of the invention, the vacuum
stripping of the precursor yielded an unexpected result. In
particular, it was previously believed that in order to maintain a
stable microemulsion of the liquid overbased alkaline earth salt of
the fatty acid, the liquid hydrocarbon and alcohol components of
the continuous phase were both necessary in the final reaction
product. However, it was unexpectedly observed that upon subjecting
the precursor to vacuum stripping, not only did the final product
maintain its shelf stable and flowable liquid properties, but it
was determined that the final product had a final non-volatile
matter content of at least 95% and a flash point of greater than
93.degree. C. (about 200.degree. F.).
[0041] The reaction mixture for an overbased calcium oleate, after
addition of the slurry and carbonation with carbon dioxide and
after vacuum stripping, has the following composition ranges:
[0042] Calcium oleate about 15-40% by weight [0043] Calcium
carbonate about 9-35% by weight [0044] Hydrocarbon oil about 25-35%
by weight [0045] Dodecanol (co-surfactant) less than about 5% by
weight [0046] Propylene glycol less than about 1% by weight
[0047] Substitution of magnesium, strontium, or barium for calcium
in the overbased salt is done on an equivalent basis of the metal
hydroxide. On the basis of the final reaction mixture prior to
vacuum stripping, the following amounts may be used: [0048]
Ca(OH).sub.2 (lime) about 15-35% by weight [0049] Mg(OH).sub.2
about 12-24% by weight [0050] Sr(OH).sub.2 about 25-50% by weight
[0051] Ba(OH).sub.2 about 35-50% by weight
[0052] The following Examples illustrate the preparation of the
shelf stable haze free liquids of the overbased salts in accordance
with the method of the present invention, but these examples are
not considered to be limiting the scope of this invention. Unless
otherwise indicated in the following examples and elsewhere in the
specification and claims, all parts and percentages are by weight,
and all temperatures are in degrees Fahrenheit.
EXAMPLES
Formation of Overbased Calcium Oleate Precursor I
Example 1
[0053] A 15% overbased calcium oleate/carbonate was prepared
according to this Example. A mixture of about 274.3 g of oleic
acid, about 270.0 g of D-80, about 140.3 g of dodecanol, about 50.0
g of propylene glycol and about 25.0 g of water was heated to about
88.degree. C. (about 190.degree. F.), with stirring, under a
nitrogen atmosphere. To the stirred mixture there was continuously
added a dispersion comprised of about 140.4 g of D-80, about 85.0 g
of dodecanol, about 25.0 g of propylene glycol and about 276.7 g of
lime for about 50 minutes to produce a solution of calcium oleate
in the mixture. At this point in the reaction, the mixture tested
basic with phenolphthalein (about 10-12 pH). Then, to the stirred
mixture there was continuously added, over a period of about 3
hours, the mixture was treated with carbon dioxide at 1.5 SCFH at
about 93.degree. C. (about 200.degree. F.). The basicity of the
reaction was checked to maintain the basicity during the reaction.
When the reaction mixture tested nearly neutral to phenolphthalein,
the carbon dioxide addition was discontinued. The reaction mixture
was then heated to about 149.degree. C. (about 300.degree. F.), and
a total of 85.2 g of water was removed via a Dean-Stark trap. The
resulting product mixture was stirred and 24.00 g of filter aid
(diatomaceous earth) was added. The product mixture was filtered
with suction, as stated above in the description, at over 500 ml
per 10 minutes, yielding a shelf stable, flowable liquid filtrate
of overbased calcium oleate/carbonate which remained shelf stable
upon cooling to room temperature.
Vacuum Stripping of Overbased Calcium Oleate Precursor I
Example 2
[0054] A 250 ml three neck round bottom flask was charged with the
precursor obtained in Example 1. The three neck round bottom flask
was then fitted with a nitrogen inlet to sparge the mixture in one
neck of the flask, a temperature probe in another neck of the flask
and a vacuum line in the other neck of the flask. The vacuum
filtration was conducted at a temperature between about 149.degree.
C. (about 300.degree. F.) and about 163.degree. C. (about
325.degree. F.) with the nitrogen gas supplied at a rate of 6 cubic
feet per hour (SCFH). A total distillate of about 678.6 g was
collected yielding a non-volatile matter content of about 84.2% and
the filtrate was analyzed to contain about 14.8% calcium by weight.
After the addition of about 50.0 g 6.0 cSt PAO to the mixture,
further vacuum filtration was conducted as described above. After
an additional three hours of filtration, it was determined that the
mixture had a non-volatile matter content of about 99.4% and the
filtrate was analyzed to contain about 15.7% calcium by weight. The
final product had the following physical properties: [0055] Flash
point-->200.degree. C. (about 392.degree. F.) [0056] Specific
gravity--about 1.162 [0057] Weight per gallon--9.68 [0058] %
Volatile by volume--<1 [0059] % Volatile by weight--<1
[0060] As seen in FIG. 1, a graph of a thermogravimetric analysis
(TGA) of the vacuum-stripped final product is provided. The
analysis was conducted using a Seiko 5200 TG/DTA. The sample was
evaluated from about 30.degree. C. (about 86.degree. F.) to about
550.degree. C. (about 1022.degree. F.) at a rate of 10.degree.
C./min. The thermogram (TG %) of the final product shows the
decomposition of the final product as a function of temperature.
The weight loss profiles, as designated by inflection points on the
TG % curve of the final product, were determined to be 86.3% at
298.2.degree. C. (about 568.degree. F.), 56.99% at 436.9.degree. C.
(about 819.degree. F.) and 38.6% at 496.0.degree. C. (about
925.degree. F.). The inflection points represent a point or
temperature on a curve at which the curvature of the plot changes
sign during the decomposition of the various components of the
final product, including various forms of calcium carbonate
including calcite, vaterite and/or aragonite if present. The
inflection points are represented by the first derivative curve
(DTG %/min). These results suggest that the vacuum-stripped final
product of the shelf stable, flowable overbased alkaline earth salt
of the fatty acid has a non-volatile matter content greater than
95% when measured at 200.degree. C. (about 392.degree. F.).
Formation of Overbased Calcium Oleate Precursor II
Example 3
[0061] A 15% overbased calcium oleate/carbonate was prepared
according to this Example. A mixture of about 274.3 g of oleic
acid, about 270.0 g of D-80, about 140.3 g of dodecanol, about 50.0
g of propylene glycol, about 100.0 g of 6.0 cSt PAO and about 25.0
g of water was heated to about 88.degree. C. (about 190.degree.
F.), with stirring, under a nitrogen atmosphere. To the stirred
mixture there was continuously added a dispersion comprised of
about 140.4 g of D-80, about 85.0 g of dodecanol, about 25.0 g of
propylene glycol, about 50.0 g of 6.0 cSt PAO and about 277.0 g of
lime for about 50 minutes to produce a solution of calcium oleate
in the mixture. At this point in the reaction, the mixture tested
basic with phenolphthalein (about 10-12 pH). Then, to the stirred
mixture there was continuously added, over a period of about 3
hours, the mixture was treated with carbon dioxide at 1.5 SCFH at
about 93.degree. C. (about 200.degree. F.). The basicity of the
reaction was checked to maintain the basicity during the reaction.
When the reaction mixture tested nearly neutral to phenolphthalein,
the carbon dioxide addition was discontinued. The reaction mixture
was then heated to about 149.degree. C. (about 300.degree. F.), and
a total of about 110.0 g of water was removed via a Dean-Stark
trap. The resulting product mixture was stirred and 26.00 g of
filter aid (diatomaceous earth) was added. The product mixture was
filtered with suction, as stated above in the description, at about
1000 ml in about 5.5 minutes and about 1225 ml in about 7 minutes,
yielding a shelf stable, flowable liquid filtrate of overbased
calcium oleate/carbonate which remained shelf stable upon cooling
to room temperature.
Vacuum Stripping of Overbased Calcium Oleate Precursor II
Example 4
[0062] The procedure according to Example 3 was repeated and the
filtrate from both procedures, which resulted in a total of about
2,032 g of product, was combined and prepared for vacuum stripping.
A three neck round bottom flask was charged with the precursor
material obtained in the two preparations according to Example 3.
The three neck round bottom flask was then fitted with a nitrogen
inlet to sparge the mixture in one neck of the flask, a temperature
probe in another neck of the flask and a vacuum line in the other
neck of the flask. The vacuum filtration was conducted at a
temperature between about 149.degree. C. (about 300.degree. F.) and
about 163.degree. C. (about 325.degree. F.) with the nitrogen gas
supplied at a rate of 6 cubic feet per hour (SCFH). About 7.5 hours
into the vacuum stripping of the sample, the non-volatile matter
content was determined to be about 95.3% and the filtrate was
analyzed to contain about 15.7% calcium by weight. After the
addition of about 25.0 g of 6.0 cSt polyalphaolefin (PAO) to the
mixture, further vacuum filtration was conducted as described
above. After an additional four hours of filtration, it was
determined that the mixture had a non-volatile matter content of
about 98.2% and the filtrate was analyzed to contain about 15.7%
calcium by weight. An additional amount of about 45.0 g of 6.0 cSt
PAO was added to the mixture in order to adjust the final calcium
content measured to be about 15.3% calcium by weight. The final
product had the following physical properties: [0063] Flash
point-->200.degree. C. (about 392.degree. F.) [0064] Specific
gravity--about 1.144 [0065] Weight per gallon--9.53 [0066] %
Volatile by volume--<1 [0067] % Volatile by weight--<1
[0068] Based upon the foregoing disclosure, it should now be
apparent that the overbased, shelf stable, flowable liquid of an
alkaline earth metal salt of a fatty acid and a process for
preparing the liquid as described herein will carry out the objects
set forth hereinabove. It is, therefore, to be understood that any
variations evident fall within the scope of the claimed invention
and thus, the selection of specific component elements can be
determined without departing from the spirit of the invention
herein disclosed and described.
* * * * *