JPS6128599A - Azeotropic composition of trichlorotrifluoroethane, acetone,nitromethane and hexane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to azeotropic mixtures of trichlorotrifluoroethane, acetone, nitromethane and hexane. These mixtures are useful in a variety of vapor degreasing or solvent cleaning applications, including desolvent removal.

Vapor degreasing and solvent cleaning with fluorocarbon-based solvents is widely used in industry for degreasing and other cleaning of solid surfaces, especially complex parts and where dirt removal is difficult.

In its simplest form, degreasing or solvent cleaning involves exposing the room temperature object to be cleaned to boiling solvent vapor. The vapor that condenses on the object becomes a clean distilled solvent that washes away grease or other dirt. Finally, when the solvent is evaporated from the object, nothing is left behind, just as if the object were simply washed in a liquid solvent.

For operation of large assembly lines where high temperatures are required to further enhance the cleaning action of solvents, where dirt removal is difficult, or where metal parts and assemblies must be cleaned effectively and quickly. Traditional vapor degreasing operations involve submerging the part to be cleaned into a sump of boiling solvent that removes dirt clumps, then placing the part into a sump containing freshly distilled solvent at around room temperature, and The final step consists of exposing the part to solvent vapors on a boiling tank which condense on the cleaning part. Additionally, the area may be sprayed with a vaporizing solvent before the final rinse.

Steam degreasers suitable for the above operations are well known in the art. For example, U.S. Pat. has been done.

Fluorocarbon solvents, such as trichlorotrifluoroethane, have been widely used in recent years as effective, non-toxic, non-flammable agents useful in degreasing applications. In particular, trichlorotrifluoroethane has been found to have excellent dissolving power for greases, oils, waxes, and the like. Therefore, motors, compressors, heavy metal parts, delicate precision metal parts, printed circuit boards, gyroscopes,
Guidance equipment, Space 2 and Missile Nordware,
It has been found that it is widely used for cleaning aluminum parts, etc. However, depending on the purpose of dissolution, trichlorotrifluoroethane alone may not have sufficient dissolving power. Since IJ fluoroethane (trichloro) is non-polar, it does not remove polar pollutants sufficiently.

Therefore, to overcome this drawback, trichlorotrifluoroethane has been mixed with polar components, such as aliphatic alcohols or chlorocarbons such as methylene chloride. For example, U.S. Patent No. 3,881,949
A mixture of dichloro-1,112-) dichloro-1,2,2-trifluoroethane and ethanol is used as a solvent for vapor degreasing bales.

The art has discovered that components that impart further desirable properties, such as polar functionality, enhanced solvency, and stabilizers 1.1.
We have particularly aimed at azeotropic compositions containing the desired fluorocarbon component, such as trichlorotrifluoroethane. Azeotropic compositions are preferred because they have the lowest boiling point composition and do not fractionate upon boiling. This is preferred in the vapor degreasing equipment described above using these solvents, as redistilled material is created for the final rinse. Therefore, this distillation degreasing apparatus functions as a still.

If the solvent composition does not exhibit a constant boiling point, ie, is not an azeotrope or azeotrope, fractionation will occur, resulting in undesirable solvent distribution and impairing the integrity of cleaning and handling. If the solvent mixture is azeotropic or non-azeotropic, the more volatile components of the mixture will selectively evaporate, resulting in undesirable properties such as poor soil-solvating power or metal, plastic or elastomer components. The result is a mixture with components that are less inert to water and more flammable and toxic.

Several azeotropic compositions based on trichlorotrifluoroethane have been tested and in some cases found to be useful as versatile vapor degreasing solvents. For example, U.S. Patent No. 2,999.815 includes 1,1.
2-Trichloro-1,2° is described as an azeotrope of 2-trifluoroethane and acetone; US Pat. No. 3,5
No. 73,213 contains 1.1.2-trichloro-1.2.
An azeotrope of 2-trifluoroethane and nitromethane is shown; US Pat. No. 4,045,366 shows 1,
1゜2-) A ternary azeotrope containing trichlorotrifluoroethane, nitromethane and acetone has been described; and as in U.S. Pat. An azeotropic composition is shown.

The industry continues to seek other new fluorocarbon-based azeotropes or azeotropes for new specialized applications in vapor degreasing and for other cleaning applications.

Accordingly, it is an object of the present invention to provide a 1,1. ．． The object of the present invention is to provide a new azeotropic composition based on 2-trichloro-1°2.2-trifluoroethane.

Another object of the present invention is to provide a new constant boiling point or essentially constant boiling point solvent which is liquid at room temperature, does not fractionate under the conditions of use and also has the above-mentioned advantages. be.

Yet another objective is to, both in the liquid and vapor phase,
It is an object of the present invention to provide azeotropic compositions that are relatively non-toxic and non-flammable.

The present invention provides trichlorotrifluoroethane, acetone,
It consists of nitromethane and hexane, and trichlorotrifluoroethane is 1,1°2-trichloro-1,
We have discovered a new azeotropic composition in which 2,2-trifluoroethane is preferred. In the present invention, the azeotropic composition comprises 72.7-87.8% by weight of 1,1,2-trichloro-1,2°2-trifluoroethane, io, o-16
, 6% by weight acetone, 0.005-1.5% by weight nitromethane and 0.2-10.6% by weight hexane.

In a preferred embodiment of the invention, the azeotrope is 77.9
~87.6% by weight of 1,1.2-trichloro-1.2.
2-trifluoroethane, 10.0-14.2%)
of acetone, 0.05-0.9% by weight of nitromethane and 1.0-7.9% by weight of hexane. Such compositions have a constant or essentially constant boiling point of about 44.0°C at 760 mmHy. Although the exact azeotropic composition was not measured, it was found to be within the above range. Regardless of the composition of the true azeotrope, all compositions within this indicated range as well as specific compositions outside the indicated range are
An azeotropic composition, as defined in more detail below.

These azeotropic compositions are stable and safe to use, and the preferred compositions are non-flammable (Tag Oven Cup test method - ASTM D'). When tested with l 310-16-, it does not show a flash point),
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These compositions can be particularly effective when used in conventional degreasing equipment for dissolving lubricating oils and machine cutting oils and cleaning such oils from solid surfaces. Understood.

For the purposes of this discussion, an azeotropic composition is defined as having a constant boiling point or no tendency to fractionate during boiling or evaporation (from the point that the entire behavior of a true azeotrope is Such a composition may or may not be a true azeotrope.Thus, in such a composition, the composition of the vapor produced during boiling or evaporation is the same or substantially the same as the initial liquid composition. Therefore, any changes in liquid composition during boiling or evaporation are minimal or negligible.

This is in contrast to non-azeotropic compositions where the liquid composition changes considerably during boiling or evaporation.

As is well known in the art, another characteristic of azeotropic compositions is that there is a range of azeotropic compositions containing the same components in different proportions. All these compositions are here encompassed by the term azeotropic. For example, it is well known that at different pressures the composition of an azeotrope changes at least slightly, and that a change in distillation pressure also changes the distillation temperature at least slightly. Therefore, although the azeotrope of A and B shows a unique relationship,
The various compositions depend on temperature and/or pressure.

1.1.2-Trichloro-1,2,2-) of the novel solvent azeotropic composition of the present invention! J fluoroethane, acetone,
All nitromethane and hexane components are commercially available. Preferably, they should be of sufficiently high purity to avoid adversely affecting the solvency and constant boiling properties of the system.

For example, a suitable 1,1,2-trichloro-1,2゜2-trifluoroethane is available under the trade name "GENESO".
LV@D” and is sold by Allied.

The term ``hexane'' is used here to refer to any C6 para'
'Hackhl Chemical Dic' is also used to mean 'Hackhl Chemical Dic'.
tiOnly.

3rd edition, McGraw Hill Book (194, 4), 7)
.

408). Therefore, the word "hexane" has n-
hexane, 2-methylpentane, 3-methylpentane,
2,2-dimethylbutane, 2,3-dimethylbutane and mixtures of any and all of these are included.

In particular, from about 35 to about 100 mixed with other hexane isomers.
Included are commercially available "isohexanes" containing primarily 2-methylhardane in weight percent. Each hexane isomer separately and in combination with other hexane isomers forms an azeotropic composition with 1.1.2-trichloro-1,2,2-trifluoroethane, acetone and nitromethane according to the present invention. I found out what to do.

It will be apparent to those skilled in the art that for special purposes, various additives such as lubricants, detergents, etc., may be incorporated into the novel azeotropic compositions of this invention. These additives are selected so as not to adversely affect the essential properties of the composition for the particular application.

Example 1 About 84% by weight of 1,-1 based on the total weight of the mixture
, 2-) Fuchloro1.2.2-trifluoroethane, containing about 12% by weight acetone, about 2% by weight n,-hexane and about 1% by weight nitromethane, about 500
0g of solvent mixture was produced.

This mixture was transferred to a four-plate column, distillation head and AST.
A 51 three-necked flask with an M scale thermometer was used for distillation. The distillation step involves refluxing the solvent mixture for approximately 1 hour;
and consists of collecting 8 fractions. Discard the first and last 6 300 #Il fractions, and soak the remaining fraction for about 1 hour.
Redistilled and aggregated the 6 distillates. Again, the first and last fractions were discarded. The atmospheric pressure measured for the amount of distillation was approximately 754.2 mmHg.

The distillation rate is approximately 1. Oml: 7 minutes. Average density is 2
4 fractions of approximately 1.366 g/ml at 5°C (below 77°C)
℃ and collected. The analysis of the four fractions by gas chromatography is shown in Table 1 below.
12.21.6 0.043 86.1 1Z21.7
0.064 86.0 1Z21. ．． 8 0.07 Example 2 Approximately 84% by weight of 1,1,2-trichloro-1°2.24
The procedure of Example 1 was repeated with a solvent mixture containing lifluoroethane, about 12% by weight acetone, about 2% by weight luhexane, and about 1% by weight nitromethane. All weight percentages are based on the total weight of the mixture. The atmospheric pressure is about 744.
It was 4 mmHy. Distillation speed is about 20! nl/min,
Distillation temperature was approximately 43.8°C. The specific gravity is 23℃ (74
(lower) was approximately 1.368 g/ml. Four fractions were analyzed by gas chromatography. The results are shown in Table 1I below.

Fuck ■ 1 B5.9 12.6 1
．． 5 0.042 85.9
144 1.6 0.063 8
5.9 125 1.6 0.
084 85.8 12.4 1
．． 8 0.08 Example 3 To complete all flash point measurements of the novel azeotropic composition of the present invention
We conducted a series of experiments. Analysis of the compositions tested in these tests is shown in Table 1 below.

Table ■ Acetodi 12.4 hexane 1.6 nitromethane
0.5 ASTM method Z) 1310
° “Tag Open - Flash Point of Liquid with Cup Device”
Accordingly, the flash point 't 611+ of the above composition was determined.

The solvent mixture was cooled so that the starting point for this test was 10°C (below 50°C).

This test was performed twice. The same results were obtained: this four-component mixture had no flash point and failed at 46°C (114″F).

Example 4 Representative embodiments of compositions of the present invention were evaluated in stability tests. The analysis results of the compositions used in this test are shown in the following table (■).

Table ■ Ingredients Weight% Trichlorotrifluoroethane 85.5 Acetone
12.4 hexane
16 nitromethane 0
．． 5 The above composition was refluxed at autogenous pressure for 48 hours in the presence of zinc and aluminum metals. The compositions were then analyzed for the presence of chloride ions.

The greater the amount of chloride ions, the more the solvent will decompose. For comparison purposes, the product name is “GENESO”
Manufactured and sold by Allied with LV■404'',
about 83 to about 85% by weight of 1,1°2-trichloro-1,
2,2-trifluoroethane, about 12.5 to about 13.5
wt% acetone and about 2.5 to about 3.5 wt% n
Similar tests and analyzes were performed using azeotropic compositions containing ~hexane.

The results of these tests are shown in the following table (■).

GENESOLV”l, 04 Zinc .7GE
NESOLV@404 7#=E=ue. , 5. None of the above mixtures (0,005 The above mixture Zinc 0.1 The above mixture Aluminum 0.17) The analysis of this composition is shown in the following table.

Table ■ Ingredients Weight % Trichlorotrifluoroethane 7 85.8 Acetone 12.5 Hexane
], 6 nitromethane
01 The test results are shown in the following table (■).

Table ■ ・GENESOLV■404 Zinc 13
0GENESOLV@404 7xi=fih
0.34 Mixture of the above None 0
．． 34 Mixture of the above Zinc 0.0
3 Mixture of the above Aluminum α04 Example 6 The azeotropic composition of the present invention is such that the distillate is more highly rectified than that found in most sought after degreaser systems. Using a distillation method, a five-stage theoretical plate with limited head Oldershat (Oldershatn)
A distillation column was used. Typically, approximately 35 Qcr- of liquid was placed in the distillation pot. This liquid was a mixture of various combinations of 1,1,2-trichloro-1,2,2-trifluoroethane, acetone, nitromethane, and hexane.

The mixture was heated at total reflux for approximately 1 hour to ensure equilibrium. In most cases, the distillate was obtained at a boiling rate of 400-500 g/h and a reflux ratio of 2:1. Approximately 300 Cp of product was distilled and six approximately equal amounts of overhead fractions were collected.

Vapor temperature (of the distillate), pot temperature and pressure were monitored. Fractions with a constant boiling point were collected, and the weight percentages of the components were determined by gas chromatography analysis. Next, a mixture consisting of the approximate composition of the fractions with a constant boiling point was prepared and double distilled under the same conditions. The compositions of distillate 2 and the residue were compared by chromatographic analysis to confirm that the mixture had a constant boiling point. The mixture of constant boiling point obtained by the above distillation method according to the present invention is
Shown below.

Table ■ Acetone 12.9 Examples 7-9 Distillation apparatus and procedure described in Example 6 above? using, 1
, 1,2-trichloro-1,2,2-trifluoroethane, acetone, nitromethane and hexane, the composition range in which the boiling point is constant was investigated. A distillation pot was charged with a mixture of 1,1,2-trichloro-1,21,2-)fluoroethane (FC-113), acetone, nitromethane, and hexane.

These examples show that each hexane isomer is ■.

1.2-trichloro-1.2.2-trifluoroethane, exhibiting its own identity as a unique compositional component in an azeotrope with acetone and nitromethane;
and each hexane isomer and mixtures thereof are shown to form an azeotrope with such constituents having a constant boiling point of about 44.0±0.2°C. This is quite surprising considering the considerable differences in boiling points between the various hexane isomers. The hexane isomers and their boiling points are shown in the following table.

Table ■ Hexane isomers Standard boiling point (°C) 2.2-Dimethylbutane 49.75 (2,2-DMB) 2.3-7 Methylbutane 58. IC2,3-D
MB) 2-methylpentane 6Q, 13 (isohexane) (2-MP) 3-methylpentane 64 (3-MP) n-hexane 68.74 (n-h
eπ) Several distillations were carried out with different compositions of the starting mixture, the resulting fractions of constant boiling point were collected, analyzed by gas chromatography, and the vapor temperature and pressure were recorded. In order to standardize the boiling points observed on different days to a mercury pressure of 760 mmHy, the approximate normal boiling point of a mixture rich in 1,1,2-trichloro-1,2,2-trifluoroethane was applied to the observed value. It was estimated by applying a pressure correction factor of about 26 Hy/°C. While I was there,
It should be noted that this corrected boiling point is generally accurate to ±0.4°C and is only useful for rough comparisons of boiling points measured on different days. above .

Approximately 44.0± at 760 mmHy depending on the method
A mixture with a constant boiling point that boils at 0.2°C has a temperature of 77.
9-81.3% by weight of 1.1.2-)lichloro-1°2
．． 2-trifluoroethane, 12.9-14.2% by weight
of acetone, 0.05-0.2% by weight of nitrilomethane and 5.6-7.9% by weight of hexane. Confirmatory distillation data for the mixtures investigated are shown in Table X.

From the foregoing, it is clear that other constant or essentially constant boiling point mixtures of the same components can be readily identified by those skilled in the art using the methods described above.

A true azeotrope of the system consisting of 1,1,2-)lichloro-1,2,2-trifluoroethane, acetone, nitromethane and hexane is also present outside the compositional range in which the boiling point is constant or essentially constant. Limits were also not sufficiently characterized or defined. As mentioned above, those skilled in the art will appreciate that "constant boiling point" or "essentially constant boiling point" for purposes and purposes of the present invention refers to the meaning of "constant boiling point" or "essentially constant boiling point" for vapor degreasing systems such as those used in the art. The boiling point is constant or essentially constant in the environment.
Other mixtures of gold of constant boiling point or essentially boiling point -W can be readily identified. All such mixtures according to the invention which have a constant or essentially constant boiling point are referred to herein as "azeotropic mixtures".

Example 10 To illustrate the azeotropic properties of the inventive mixture under practical conditions in a vapor phase degreasing operation, about 81.3% by weight of 1,1,2-tIJ was added to a vapor phase degreaser Kuroro 1
．． 2.2-trifluoroethane (FC-113), approx.
A preferred azeotrope of the present invention was charged consisting of 3.1% by weight acetone, about 5.4% by weight commercially available isohexane, and about 0.2% by weight nitromethane. The mixture was evaluated for boiling point constancy or non-separability. The solvent is Baron Blake,
slee) in a refrigerated three-volume VPD (Series 5000-Model/16MLR-216). The bath salts were refluxed and the composition of the individual reservoirs was determined using a Hyurift Pancard 5890 gas chromatograph. Reflux is 2
The composition of this open face was monitored for 1 hour. For any mixture component, the maximum concentration difference between the reservoirs is 0.
Below 3%, the mixture was considered constant boiling or non-separable.

If the mixture is not azeotropic, the high boiling components will rapidly condense in the boiling catch and the rinse basin will empty.

As the data in Table ■ show, this did not occur. These results demonstrate that the compositions of the present invention do not segregate in commercial vapor degreasers, thereby avoiding potential safety, performance and handling problems. Preferred compositions tested also include AST
MD-56 (tag closed cup) and A
It was also found that srun-1310 (tag open cup) had no flash point.

Table Composition (wt%) Boiling reservoir acetone 13.05 12.86
12.87 Nitromethane (L20 0
．． 55 0.57FC-11381,3981,1
981,11 Commercially available isohexane 536
5.40 5.47 Action reservoir acetone 1. SO713,1543,1
2 Nitromethane 0.20 0.15
0.15FC-11381, 2881, 3381, 36
Commercially available isohexane S44・5.38
5.37 Rinse reservoir acetone 13.0B 13.13
13.22 Nitromethane 0.21
0.15 0.12FC-11381, 2981,
3481,28 Commercially available isohexane 5.43
5.39 5.38a) Analytical Criteria - Representative Initial Compositions of All Three Reservoirs Example 11 This example describes the use of a preferred azeotropic composition of the present invention for cleaning metal parts.

Cleaning was performed using a Brannon B-400 double steam degreaser. The first reservoir is used as a working surface and contains about 81.3% by weight of 1,-1,2-trichloro-1°2,2-trifluoroethane, about 13.2% by weight of acetone, about 54% by weight of acetone,
A solvent consisting of % commercially available isohexane and approximately 0.1% nitromethane by weight was used. The second reservoir was used as a rinse reservoir. The cooled cooling coils are lined up on the upper inner wall of the device and continue to be flushed with steam from the negative side.

Two types of dirt, 1.9 cm x 7.6 cm (%
I painted it on a metal coupon of ``X3''). These were 316 stainless steel and 1010 cold rolled steel. The stain was selected from the following two types of metal working fluids: Name Kozo Type □−→□h□→□ −−L ÷□−□□ −□−h□−
轡→-ri□--→U-K1--i-□Hocut71L
EF Horton & Co. Semi-synthetic Trir
nsol Master Chemical Co. Emulsifying metal coupons were polished to a clean new surface overall. The coupons were rinsed with deionized water, followed by methanol, and allowed to air dry for 10 minutes.

Four identical coupons were then dipped into each metal working fluid.

Cleaning tests were performed on these two coupons immediately after being immersed in metal working fluid. The other two coupons are 24
Tested after standing for a period of time. The parts were placed on a shelf in a stainless steel basket for cleaning. In the first step, the assembly was soaked in the working stop for 2 minutes, then transferred to the rinse basin for 2 minutes, and then solvent sprayed in the steam zone for 2 minutes.

The final step is to remain in this vapor zone for 1 minute.

The processed coupons were visually inspected for any remaining soil. A drain test was also conducted in which the coupons were immersed in water and drained for 10 seconds. During the 10 second drain period, the surface of the coupon was examined to see if the water film had broken. A coupon was considered to be generally clean if no residual dirt or breaks in the water film were visible on the coupon surface during the drain test. In the above method, with "316" stainless steel coupon fTrimsol metal working fluid and with 101
0" Cold Roll Steel - Pon f: Soiled with Hoc1Lt711 metal working fluid. All of these soiled coupons were cleaned with the preferred azeotropic composition of the present invention and evaluated for cleanliness as described above. All coupons were determined to be completely clean.

Claims (11)

[Claims] (1) An azeotrope-like composition consisting of trichlorotrifluoroethane, acetone, nitromethane and hexane. (2) The above trichlorotrifluoroethane is 1,1,2
-Trichloro-1,2,2-trifluoroethane, the azeotrope-like composition according to claim (1). (3) The azeotrope-like composition according to claim (2), wherein the hexane is n-hexane. (4) The azeotrope-like composition according to claim (2), wherein the hexane is 2-methylpentane. (5) The azeotrope-like composition according to claim (2), wherein the hexane is 3-methylpentane. (6) the hexane is 2,2-dimethylbutane;
An azeotrope-like composition according to claim (2). (7) the hexane is 2,3-dimethylbutane;
An azeotrope-like composition according to claim (2). (8) The azeotrope-like composition according to claim (2), wherein the hexane is isohexane. (9) 72.7 to 87.8% by weight of 1,1,2-trichloro-1,2,2-trifluoroethane, 10.0
from 0.005 to 16.6% by weight acetone, from 0.005 to 1
．． 5% by weight nitromethane and 0.2 to 10.6
An azeotrope-like composition according to claim 2, comprising % by weight of hexane. (10) 77.9 to 87.6% by weight of 1,1,2-
Trichloro-1,2,2-trifluoroethane, 10.
0 to 14.2% by weight acetone, 0.05 to 0
．． An azeotrope-like composition according to claim 2, comprising 9% by weight of nitromethane and 1.0 to 7.9% by weight of hexane. (11) 85.0 to 86.5% by weight of 1,1,2-
Trichloro-1,2,2-trifluoroethane, 12.
0 to 13.0% by weight acetone, 0.03 to 0
．． Claim (2) consisting of 5% by weight of nitromethane and 1.0 to 2.0% by weight of n-hexane.
The azeotrope-like composition described in Section 1.