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Description  |
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FIELD OF THE INVENTION
The present invention relates to azeotrope-like compositions of
1,1,2-trichloro-1,2-trifluoroethane; 1,2-dichloroethylene; and an alkanol
having 3 to 7 carbon atoms. These azeotrope-like compositions are useful
in a variety of vapor degreasing, cold cleaning, and solvent cleaning
applications including defluxing.
CROSS-REFERENCE TO RELATED APPLICATION
Co-pending, commonly assigned patent application Ser. No. 278,404 filed
Dec. 1, 1988 discloses azeotrope-like compositions of
1,1,2-trichloro-1,2,2-trifluoroethane; 1,2-dichloroethylene; methanol;
1-chloropropane; and nitromethane.
BACKGROUND OF THE INVENTION
Vapor degreasing and solvent cleaning with fluorocarbon based solvents have
found widespread use in industry for the degreasing and otherwise cleaning
of solid surfaces, especially intricate parts and difficult to remove
soils.
In its simplest form, vapor degreasing or solvent cleaning consists Of
exposing a room temperature object to be cleaned to the vapors of a
boiling solvent. Vapors condensing on the object provide clean distilled
solvent to wash away grease or other contamination. Final evaporation of
solvent from the object leaves behind no residue as would be the case
where the object is simply washed in liquid solvent.
For difficult to remove soils where elevated temperature is necessary to
improve the cleaning action of the solvent, or for large volume assembly
line operations where the cleaning of metal parts and assemblies must be
done efficiently and quickly, the conventional operation of a vapor
degreaser consists of immersing the part to be cleaned in a sump of
boiling solvent which removes the bulk of the soil, thereafter immersing
the part in a sump containing freshly distilled solvent near room
temperature, and finally exposing the part to solvent vapors over the
boiling sump which condense on the cleaned part. In addition, the part can
also be sprayed with distilled solvent before final rinsing.
Vapor degreasers suitable in the above-described operations are well known
in the art. For example, Sherliker et al. in U.S. Pat. No. 3,085,918
disclose such suitable vapor degreasers comprising a boiling sump, a clean
sump, a water separator, and other ancillary equipment.
Cold cleaning is another application where a number of solvents are used.
In most cold cleaning applications, the soiled part is either immersed in
the fluid or wiped with rags or similar objects soaked in solvents and
allowed to air dry.
Fluorocarbon solvents, such as trichlorotrifluoroethane, have attained
widespread use in recent years as effective, nontoxiC, and nonflammable
agents useful in degreasing applications and other solvent cleaning
applications. Trichlorotrifluoroethane has been found to have satisfactory
solvent power for greases, oils, waxes and the like. One isomer of
trichlorotrifluoroethane is 1,1,2-trichloro-1,2,2-trifluoroethane (known
in the art as CFC-113) It has therefore found widespread use for cleaning
electric motors, compressors, heavy metal parts, delicate precision metal
parts, printed circuit boards, gyroscopes, guidance systems, aerospace and
missile hardware, aluminum parts and the like.
The art has looked towards azeotropic compositions including the desired
fluorocarbon components such as trichlorotrifluoroethane which include
components which contribute additionally desired characteristics, such as
polar functionality, increased solvency power, and stabilizers. Azeotropic
compositions are desired because they do not fractionate upon boiling.
This behavior is desirable because in the previously described vapor
degreasing equipment with which these solvents are employed, redistilled
material is generated for final rinse-cleaning. Thus, the vapor degreasing
system acts as a still. Unless the solvent composition exhibits a constant
boiling point, i.e., is an azeotrope or is azeotrope-like, fractionation
will occur and undesirable solvent distribution may act to upset the
cleaning and safety of processing. Preferential evaporation of the more
volatile components of the solvent mixtures, which would be the case if
they were not an azeotrope or azeotrope-like, would result in mixtures
with changed compositions which may have less desirable properties, such
as lower solvency towards soils, less inertness towards metal, plastic or
elastomer components, and increased flammability and toxicity.
U.S. Pat. No. 3,455,835 discloses an azeotropic composition of about 54 to
about 64 percent by weight of 1,1,2-trichloro-1,2,2-trifluoroethane and
from about 36 to about 46 percent by weight of trans-1,2-dichloroethylene.
This teaching does not suggest the present azeotrope-like composition
because as is known in the art, it is difficult to predict if another
component will form a new azeotrope with a known azeotrope.
Another example is taught in U.S. Pat. No. 4,767,561. The disclosed
composition comprises from about 4 to about 72 percent by weight of
1,1,2-trichloroethane-1,2,2-trifluoroethane; from about 23 to about 29
percent by weight of trans-1,2-dichloroethylene; and from about 5 to about
7 percent by weight of methanol.
While azeotropic or azeotrope-like compositions are useful as cleaning
solvents, the azeotrope-like compositions should be stabilized against
possible changes during storage and use. One potential change is due to
chlorofluorocarbons such as trichlorotrifluoroethane hydrolyzing to form
HCl. When metallic materials are present such as occurs in many cleaning
applications, the problem is worsened because the metal acts as a catalyst
and causes the hydrolysis of trichlorotrifluoroethane to increase
expotentially. Metallic materials such as Al-2024, copper, cold rolled
steel, galvanized steel, and zinc are commonly used in cleaning apparatus.
Another potential change is due to ultraviolet light decomposing
chlorofluorocarbons such as trichlorotrifluorocarbons.
One example of a stabilized azeotrope-like composition is taught in U.S.
Pat. No. 4,804,493. The disclosed composition comprises from about 54 to
about 64 percent by weight of 1,1,2-trichloro-1,2,2-trifluoroethane and
from about 36 to about 46 percent by weight of trans-1,2-dichloroethylene
and effective stabilizing amounts of 4-methoxyphenol: 1,2-butylene oxide;
and nitromethane.
Another example of a stabilized azeotrope-like composition is taught in
U.S. Pat. No. 4,803,009. The disclosed composition comprises from about 64
to about 72 weight percent of 1,1,2-trichloro-1,2,2-trifluoroethane; about
23 to about 29 weight percent of trans-1,2-dichloroethylene; and about 5
to about 7 weight percent of methanol and effective stabilizing amounts of
4-methoxyphenol: 1,2-butylene oxide; nitromethane; and diisopropylamine.
The patent cites U.S. Pat. No. 3,960,746 which teaches that the
combination of 1,1,2-trichloro-1,2,2-trifluoroethane and lower alcohols
attacks reactive metals such as zinc and aluminum and thus, the
composition of U.S. Pat. No. 4,803,009 includes nitromethane to retard
this attack.
Other references which teach azeotrope-like compositions having the
combination of 1,1,2-trichloro-1,2,2-trifluoroethane and alcohol
stabilized by nitromethane to retard attack of metallic materials include
U.S. Pat. No. 3,789,006 (1,1,2-trichloro-1,2,2-trifluoroethane;
isopropanol; and nitromethane); U.S. Pat. No. 3,903,009
(1,1,2-trichloro-1,2,2-trifluoroethane; ethanol; and nitromethane); U.S.
Pat. No. 3,960,746 (1,1,2-trichloro-1,2,2-trifluoroethane; methanol; and
nitromethane); commonly assigned U.S. Pat. No. 4,062,794
(1,1,2-trichloro-1,2,2-trifluoroethane; methanol; ethanol; isopropanol;
and nitromethane); commonly assigned U.S. Pat. No. 4,052,328
(1,1,2-trichloro-1,2,2-trifluoroethane; ethanol; isopropanol; and
nitromethane); U.K. Pat. No. 2,066,840B
(1,1,2-trichloro-1,2,2-trifluoroethane; ethanol; nitromethane; and
acetone) Japanese Pat. Nos. 81-34,799 and 81-34,79B
(1,1,2-trichloro-1,2,2-trifluoroethane; ethanol; nitromethane; and
3-methylpentane or 2,2-dimethylbutane or 2,3-dimethylbutane); Japanese
Pat. No. 81-109,298 (1,1,2-trichloro-1,2,2-trifluoroethane; ethanol;
nitromethane; and n-hexane); commonly assigned U.S. Pat. No. 4,606,841
(1,1,2-trichloro-1,2,2-trifluoroethane; ethanol; nitromethane; acetone;
and hexane); and commonly assigned U.S. Pat. No. 4,683,075
(1,1,2-trichloro-1,2,2-trifluoroethane; methanol; nitromethane; acetone;
and methyl acetate).
SUMMARY OF THE INVENTION
The present invention provides novel azeotrope-like compositions comprising
1,1,2-trichloro-1,2,2-trifluoroethane; 1,2-dichloroethylene; and alkanol
having 3 to 7 carbon atoms. Preferably, the novel azeotrope-like
compositions comprise 1,1,2-trichloro-1,2,2-trifluoroethane;
1,2-dichloroethylene; and 2-methyl-2-propanol or 3-pentanol.
Proceeding contrary to the teachings in the art that nitromethane is
required to stabilize 1,1,2-trichloro-1,2,2-trifluoroethane when in
combination with alcohol, we found unexpectedly that the alkanol
contributes to stabilization of the 1,1,2-trichloro-1,2,2-trifluoroethane.
As such, the present invention also provides a stabilized azeotrope-like
composition of 1,1,2-trichloro-1,2,2-trifluoroethane;
1,2-dichloroethylene; and alkanol and effective stabilizing amounts of a
lower 1,2-epoxy alkane and at least one of a lower alkoxyphenol, phosphite
ester, and lower cyclic alkene.
It is an object of this invention to provide novel azeotrope-like
compositions based on 1,1,2-trichloro-1,2,2-trifluoroethane which are
liquid at room temperature, which will not fractionate substantially under
the process of distillation or evaporation, and which are useful as
solvents for use in vapor degreasing and other solvent cleaning
applications including defluxing applications.
It is a further object of the present invention to provide stabilized
azeotrope-like compositions of 1,1,2-trichloro-1,2,2-trifluoroethane and
1,2-dichloroethylene. It is an additional object of the present invention
to provide stabilized azeotrope-like compositions of
1,1,2-trichloro-1,2,2-trifluoroethane and 1,2-dichloroethylene which
minimize corrosion of metallic materials.
Other objects and advantages of the invention will become apparent from the
following description.
DESCRIPTION OF THE INVENTION
Examples of alkanols having 3 to 7 carbon atoms include 1-propanol;
2-propanol; 1-butanol; 2-butanol; 2-methyl-2-propanol;
2-methyl-l-propanol; 1-pentanol; 2-pentanol; 3-pentanol;
2-methyl-l-butanol; 2-methyl-2-butanol; 3-methyl-2-butanol;
3-methyl-l-butanol; 2,2-dimethyl-l-propanol; and 3-ethyl-3-pentanol. The
preferred alkanols are 2-methyl-2-propanol and 3-pentanol. The most
preferred alkanol is 2-methyl-2-propanol.
Preferably, the novel azeotrope-like compositions comprise effective
amounts of 1,1,2-trichloro-1,2,2-trifluoroethane; 1,2-dichloroethylene;
and 2-methyl-2-propanol or 3-Pentanol. The term "effective amounts" as
used herein means the amount of each component which upon combination with
the other components, results in the formation of the present
azeotrope-like compositions.
The dichloroethylene component may be cis-1,2-dichloroethylene;
trans-1,2-dichloroethylene; and mixtures thereof.
More specifically, when the dichloroethylene component used is
trans-1,2-dichloroethylene, novel azeotrope-like compositions have been
discovered comprising 1,1,2-trichloro-1,2,2-trifluoroethane;
trans-1,2-dichloroethylene; and 2-methyl-2-propanol which boil at about
44.5.degree. C. .+-. about 0.5.degree. C. at 760 mm Hg (101 kPa).
Preferably, novel azeotrope-like compositions comprise from about 55 to
about 70 weight percent 1,1,2-trichloro-1,2,2-trifluoroethane; from about
30 to about 42 weight percent trans-1,2-dichloroethylene; and from about
0.01 to about 3.0 weight percent 2-methyl-2-propanol which boil at about
44.5.degree. C. at 760 mm Hg (101 kPa).
More preferably, the azeotrope-like compositions of the invention comprise
from about 58 to about 67 weight percent
1,1,2-trichloro-1,2,2-trifluoroethane; from about 33 to about 41 weight
percent trans-1,2-dichloroethylene; and from about 0.01 to about 1.0
weight percent 2-methy 1-2-propanol.
More specifically, when the dichloroethylene component used in
cis-1,2-dichloroethylene, it should be understood that the aforementioned
compositional ranges for azeotrope-like compositions of
1,1,2-trichloro-1,2,2-trifluoroethane; trans-1,2-dichloroethylene; and
2-methyl-2-propanol also apply to azeotrope-like compositions of
1,1,2-trichloro-1,2,2-trifluoroethane; cis-1,2-dichloroethylene; and
2-methyl-2-propanol.
More specifically, when the dichloroethylene component used is a mixture of
trans-1,2-dichloroethylene and cis-1,2-dichloroethylene, it should be
understood that the aforementioned compositional ranges for azeotrope-like
compositions of 1,1,2-trichloro-1,2,2-trifluoroethane;
trans-1,2-dichloroethylene; and 2-methyl-2-propanol also apply to
azeotrope-like compositions of 1,1,2-trichloro-1,2,2-trifluoroethane; a
mixture of trans-1,2-dichloroethylene and cis-1,2-dichloroethylene; and
2-methyl-2-propanol.
More specifically, when the dichloroethylene component used is
trans-1,2-dichloroethylene, novel azeotrope-like compositions have been
discovered comprising 1,1,2-trichloro-1,2,2-trifluoroethane;
trans-1,2-dichloroethylene; and 3-pentanol which boil at about
45.1.degree. C. .+-. about 0.5.degree. C. at 760 mm Hg (101 kPa).
Preferably, novel azeotrope-like compositions comprise from about 55 to
about 70 weight percent 1,1,2-trichloro-1,2,2-trifluoroethane; from about
30 to about 42 weight percent trans-1,2-dichloroethylene; and from about
0.01 to about 3.0 weight percent 3-pentanol which boil at about
45.1.degree. C at 760 mm Hg (101 kPa).
More preferably, the azeotrope-like compositions of the invention comprise
from about 58 to about 67 weight percent
1,1,2-trichloro-1,2,2-trifluoroethane; from about 33 to about 41 weight
percent trans-1,2-dichloroethylene; and from about 0.01 to about 1.0
weight percent 3-pentanol.
More specifically, when the dichloroethylene component used is
cis-1,2-dichloroethylene, it should be understood that the aforementioned
compositional ranges for azeotrope-like compositions of
1,1,2-trichloro-1,2,2-trifluoroethane; trans-1,2-dichloroethylene; and
3-pentanol also apply to azeotrope-like compositions of
1,1,2-trichloro-1,2,2-trifluoroethane; cis-1,2-dichloroethylene; and
3-pentanol.
More specifically, when the dichloroethylene component used is a mixture of
trans-1,2-dichloroethylene and cis-1,2-dichloroethylene, it should be
understood that the aforementioned compositional ranges for azeotrope-like
compositions of 1,1,2-trichloro-1,2,2-trifluoroethane;
trans-1,2-dichloroethylene; and 3-pentanol also apply to azeotrope-like
compositions of 1,1,2-trichloro-1,2,2-trifluoroethane; a mixture of
trans-1,2-dichloroethylene and cis-1,2-dichloroethylene; and 3-pentanol.
The 1,1,2-trichloro-1,2,2-trifluoroethane; 1,2-dichloroethylene;
2-methyl-2-propanol; and 3-pentanol components of the novel solvent
azeotrope-like compositions of the present invention are known materials
Commercially available cis-1,2-dichloroethylene and
trans-1,2-dichloroethylene may be used in the present invention. It should
be noted that commercially available cis-1,2-dichloroethylene may also
contain trans-1,2-dichloroethylene; also, commercially available
trans-1,2-dichloroethylene may also contain cis-1,2-dichloroethylene.
Except for the preceding, the materials should be used in sufficiently
high purity so as to avoid the introduction of adverse influences upon the
solvency properties or constant-boiling properties of the system.
The boiling point of 1,1,2-trichloro-1,2,2-trifluoroethane is 47.6.degree.
C. The boiling point of trans-1,2-dichloroethylene is 47 to 49.degree. C.
The boiling point of 2-methyl-2-propanol is 89.2.degree. C. The boiling
point of 3-pentanol is 115.6.degree. C.
All compositions within the indicated ranges, as well as certain
compositions outside the indicated ranges, are azeotrope-like, as defined
more particularly below.
It has been found that these azeotrope-like compositions are on the whole
nonflammable liquids, i.e. exhibit no flash point when tested by the Tag
Open Cup test method - ASTM D 1310-86.
From fundamental principles, the thermodynamic state of a fluid is defined
by four variables: pressure, temperature, liquid composition and vapor
composition, or P-T-X-Y, respectively. An azeotrope is a unique
characteristic of a system of two or more components where X and y are
equal at the stated P and T In practice, this means that the components of
a mixture cannot be separated during distillation, and therefore are
useful in vapor phase solvent cleaning as described above.
For the purpose of this discussion, azeotrope-like composition is intended
to mean that the composition behaves like an azeotrope, i.e. has
constant-boiling characteristics or a tendency not to fractionate upon
boiling or evaporation. Thus, in such compositions, the composition of the
vapor formed during boiling or evaporation is identical or substantially
identical to the original liquid composition. Hence, during boiling or
evaporation, the liquid composition, if it changes at all, changes only to
a minimal or negligible extent. This is to be contrasted with
non-azeotrope-like compositions in which during boiling or evaporation,
the liquid composition changes to a substantial degree.
Thus, one way to determine whether a candidate mixture is "azeotrope-like"
within the meaning of this invention, is to distill a sample thereof under
conditions (i.e. resolution - number of plates) which would be expected to
separate the mixture into its separate components. If the mixture is
non-azeotrope-like, the mixture will fractionate, i.e. separate into its
various components with the lowest boiling component distilling off first,
and so on. If the mixture is azeotrope-like, some finite amount of a first
distillation cut will be obtained which contains all of the mixture
components and which is constant-boiling or behaves as a single substance.
This phenomenon cannot occur if the mixture is not azeotrope-like, i.e. it
does not behave like an azeotrope. Of course, upon distillation of an
azeotrope-like composition such as in a vapor degreaser, the true
azeotrope will form and tend to concentrate.
It follows from the above that another characteristic of azeotrope-like
compositions is that there is a range of compositions containing the same
components in varying proportions which are azeotrope-like or
constant-boiling. All such compositions are intended to be covered by the
term azeotrope-like or constant-boiling as used herein. As an example, it
is well known that at differing pressures, the composition of a given
azeotrope-like composition will vary at least slightly as does the boiling
point of the composition. Thus, an azeotrope-like composition of A and B
represents a unique type of relationship but with a variable composition
depending on temperature and/or pressure. Accordingly, another way of
defining azeotrope-like within the meaning of this invention is to state
that mixtures of 1,1,2-trichloro-1,2,2-trifluoroethane;
trans-1,2-dichloroethylene; and 2-methyl-2-propanol boil within
.+-.0.5.degree. C. of 44.5.degree. C. at 760 mm Hg (101 kPa) and mixtures
of 1,1,2-trichloro-1,2,2-trifluoroethane; trans-1,2-dichloroethylene; and
3-pentanol boil within .+-.0.5.degree. C. of 45.1.degree. C. at 760 mm Hg
(101 kPa). As is readily understood by persons skilled in the art, the
boiling point of the azeotrope-like composition will vary with the
pressure.
It should be understood that the present compositions may include
additional components so as to form new azeotrope-like compositions. Any
such compositions are considered to be within the scope of the present
invention as long as the compositions are constant-boiling or essentially
constant-boiling and contain all of the essential components described
herein.
The azeotrope-like compositions of the present invention are useful as
solvents in a variety of vapor degreasing, cold cleaning, and solvent
cleaning applications including defluxing and dry cleaning.
In the process embodiment of the invention, the stabilized azeotrope-like
compositions of the invention may be used to clean solid surfaces by
treating said surfaces with said compositions in any manner well known in
the art such as by dipping or spraying or use of conventional degreasing
apparatus.
As mentioned earlier, it is believed that 2-methyl-2-propanol or 3-pentanol
does not combine with 1,1,2-trichloro-1,2,2-trifluoroethane to attack
reactive metals but instead these alcohols help to prevent this reaction
in the azeotrope-like composition Although the azeotrope-like composition
alone is somewhat stable, the addition of a lower 1,2-epoxy alkane and at
least one of a lower alkoxyphenol, phosphite ester, and lower cyclic
alkene forms the present "stabilized azeotrope-like composition".
Examples of useful 1,2-epoxy alkanes having 3 to 6 carbon atoms include
ethylene oxide; propylene oxide: 1,2-butylene oxide: 2,3-butylene oxide:
1,2-pentylene oxide; 2,3-pentylene oxide: 1,2-hexylene oxide; 2,3-hexylene
oxide: and 3,4-hexylene oxide. The preferred lower 1,2-epoxy alkane is
1,2-butylene oxide.
Examples of useful lower alkoxyphenols include methoxyphenol, ethoxyphenol,
and propoxyphenol. The preferred lower alkoxyphenol is methoxyphenol and
the preferred methoxyphenOl is 4-methoxyphenol
Examples of useful phosphite esters include triisodecyl phosphite;
triisooctyl phosphite; triphenyl phosphite; and diisooctyl phosphite. The
preferred phosphite ester is triisodecyl phosphite.
Examples of useful cyclic alkenes having 5 to 7 carbon atoms include
cyclopentene, cyclohexene, and cycloheptene. The preferred lower cyclic
alkene is cyclopentene.
The most preferred combination is 1,2-butylene oxide with 4-methoxyphenol.
These materials are all known materials and are commercially available. It
should be noted that some commercially available
trans-1,2-dichloroethylene contains from about 100 to 1,000 parts per
million 4-methoxyphenol and 1,2-butylene oxide; this grade may be used in
the present invention.
The term "effective stabilizing amounts" as used herein means that amount
of each of the lower 1,2-epoxy alkanes, lower alkoxyphenols, phosphite
esters, and lower cyclic alkenes, which in combination with the
azeotrope-like composition of 1,1,2-trichloro-1,2,2-trifluoroethane,
1,2-dichloroethylene, and alkanol allows the composition to be used and
stored without loss of acceptable properties.
Regardless of the azeotrope-like composition, the preferred stabilized
azeotrope-like composition of the present invention contains 1,2-epoxy
alkane in an amount of from about 0.01 to about 2.0 percent by weight.
Regardless of the azeotrope-like composition, the Preferred stabilized
azeotrope-like composition of the present invention contains at least one
of a lower alkoxyphenol, phosphite ester, and lower cyclic alkene in an
amount of from about 0.01 to about 0.5 percent by weight.
The alcohols in the present azeotrope-like compositions are effective in
preventing the hydrolysis of the azeotrope-like composition in the
presence of galvanized steel in addition to aluminum-2024, copper, and
cold rolled steel. Typically, as will be explained below, when the
stabilized azeotrope-like composition is in contact with metallic
materials, the Cl.sup.- concentration is less than 40 parts per million.
Also, the metallic surface remains shiny.
The stabilized azeotrope-like composition of the present invention may be
prepared in any known manner including weighing each component and then
mixing said components.
The present invention is more fully illustrated by the following
non-limiting Examples.
EXAMPLE 1
These examples cOnfirm the existence of constant-boiling or azeotrope-like
compositions of 1,1,2-trichloro-1,2,2-trifluoroethane;
trans-1,2-dichloroethylene; and 2-methyl-2-propanol by use of an
ebulliometer.
A measured amount of 1,1,2-trichloro-1,2,2-trifluoroethane was charged into
an ebulliometer. Small increments of trans-1,2-dichloroethylene were then
added to the 1,1,2-trichloro-1,2,2-trifluoroethane. The liquid mixture in
the ebulliometer was maintained at boiling by supplemental heat Once the
formation of the binary azeotrope-like composition was confirmed by
constant-boiling, the ternary azeotrope-like composition was determined by
adding small increments of the 2-methyl-2-propanol. The formation of a
ternary azeotrope-like composition was confirmed by constant-boiling.
An azeotrope-like composition of 60 percent by weight
1,1,2-trichloro-1,2,2-trifluoroethane; 37 percent by weight
trans-1,2-dichloroethylene; and 3 percent by weight 2-methyl-2-propanol
boiled at about 44.5.degree. C.
From the above examples, it is readily apparent that additional
constant-boiling or essentially constant-boiling mixtures of the same
components can readily be identified by anyone of ordinary skill in this
art by the method described. No attempt was made to fully characterize and
define the outer limits of the composition ranges which are
constant-boiling. Anyone skilled in the art can readily ascertain other
constant-boiling or essentially constant-boiling mixtures containing the
same components
EXAMPLE 2
Example 1 was repeated except that 3-pentanol instead of
2-methyl-2-propanol was used.
An azeotrope-like composition of 60 percent by weight
1,1,2-trichloro-1,2,2-trifluoroethane; 37 percent by weight
trans-1,2-dichloroethylene; and 3 percent by weight 3-pentanol boiled at
about 45 1.degree. C.
EXAMPLE 3
Example 1 is repeated for Example 3 except that cis-1,2-dichloroethylene is
used instead of trans-1,2-dichloroethylene.
EXAMPLE 4
Example 1 is repeated for Example 4 except that trans-1,2-dichloroethylene
containing 10 weight percent cis-1,2-dichloroethylene is used.
EXAMPLE 5
Example 1 is repeated for Example 5 except that trans-1,2-dichloroethylene
containing 5 weight percent cis-1,2-dichloroethylene is used.
EXAMPLE 6
Example 1 is repeated for Example 6 except that cis-1,2-dichloroethylene
containing 10 weight percent trans-1,2-dichloroethylene is used.
EXAMPLE 7
Example 1 is repeated for Example 7 except that cis-1,2-dichloroethylene
containing 5 weight percent trans-1,2-dichloroethylene is used.
EXAMPLE 8
Example 2 is repeated for Example 8 except that cis-1,2-dichloroethylene is
used instead of trans-1,2-dichloroethylene.
EXAMPLE 9
Example 2 is repeated for Example 9 except that trans-1,2-dichloroethylene
containing 10 weight percent cis-1,2-dichloroethylene is used.
EXAMPLE 10
Example 2 is repeated for Example 10 except that trans-1,2-dichloroethylene
containing 5 weight percent cis-1,2-dichloroethylene is used.
EXAMPLE 11
Example 2 is repeated for Example 11 except that cis-1,2-dichloroethylene
containing 10 weight percent trans-1,2-dichloroethylene is used
EXAMPLE 12
Example 2 is repeated for Example 12 except that cis-1,2-dichloroethylene
containing 5 weight percent trans-1,2-dichloroethylene is used.
EXAMPLES 13-18
In the following examples, stabilized azeotroPe-like compositions
comprising 60 percent by weight 1,1,2-trichloro-1,2,2-trifluoroethane; 37
percent by weight trans-1,2-dichloroethylene; 3 percent by weight
2-methyl-2-propanol or 3-pentanol; 200 ppm 1,2-butylene oxide; and 200 ppm
4-methoxyphenol were tested for stability in the presence of metallic
materials. The metallic materials included Aluminum-2024(hereinafter
Al-2024), Copper(hereinafter Cu), Cold Rolled Steel(CRS), and Galvanized
Steel(GS)
In each Example, the mixture of 1,1,2-trichloro-1,2,2-trifluoroethane;
dichloroethylene; 4-methoxyphenol; and 1,2-butylene oxide was
oversaturated with water in order to create the worse possible scenario
Then, one of the alkanols listed below was added to the mixture About 125
milliliters of the water saturated five component mixture were then
transferred into a 250 milliliter pyrex flask which connected to a
water/glycol cooled condenser On top of the condenser, a Drierite
desiccant tube was installed to prevent ambient moisture from leaking into
the system.
A metal strip was placed in the middle of the liquid-vapor phases because
corrosion tends to begin at the liquid-vapor interface. The water
saturated five component mixture with the metal strip therein was under
total reflux at its boiling temperature for seven days.
Observations were made daily The recorded changes in the metallic surface
(METAL in the Tables below) such as the loss of luster (LL in the Tables
below), stain, and corrosion if any are in the Tables below. The recorded
coloration of the five component mixture (SOLVENT in the Tables below) and
increase in viscosity of the five component mixture are also in the Tables
below. In the Tables, CL means colorless, NV means nonviscous, and NC
means no change.
At the end of seven days, the pH value was determined for each of the five
component mixtures tested and the pH ranged from 4.8 to 6.0. The Cl.sup.-
concentration as determined by ion chromatography in parts per million is
in the Tables below.
TABLE I
______________________________________
AL-2024
EXAMPLE ALKANOL Cl.sup.-
METAL SOLVENT
______________________________________
13 2-methyl-2-propanol
0.03 NC CL/NV
14 3-pentanol 0.03 NC CL/NV
______________________________________
TABLE II
______________________________________
CU
EXAMPLE ALKANOL Cl.sup.-
METAL SOLVENT
______________________________________
15 2-methyl-2-propanol
0.03 NC CL/NV
16 3-pentanol 0.02 NC CL/NV
______________________________________
TABLE III
______________________________________
CRS
EXAMPLE ALKANOL Cl.sup.-
METAL SOLVENT
______________________________________
17 2-methyl-2-propanol
0.03 NC CL/NV
18 3-pentanol 0.05 NC CL/NV
______________________________________
COMPARATIVE AND EXAMPLES 19-20
Performance studies were conducted wherein metal coupons were cleaned using
the present stabilized azeotrope-like compositions as solvents The metal
coupons were so | | |
