JPS5851995B2 - Stabilization method for 1,1,2↓-trichloro↓-1,2,2↓-trifluoroethane solvent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 1,1,2-trichloro-1,2,2-trifluoroethane (hereinafter referred to as Freon 113) and its mixed solvent.
By adding a nitro compound and glycidol to No. 3 and its mixed solvent, the decomposition of the solvent is prevented and the corrosion of metal materials is prevented.

In the present invention, the 1,1.2-1-lichloro-1,2゜2-trifluoroethane solvent refers to a mixed solvent containing Freon 113 and Freon 113, and the mixed solvent containing Freon 113 refers to Freon 113. Examples of organic solvents used for this purpose include lower aliphatic alcohols such as methanol, ethanol, and isopropanol;
Examples include compounds having a carbonyl group such as acetone and methyl ethyl ketone, and various halogenated hydrocarbons including methylene chloride.

Freon 113 and its mixed solvents have excellent properties such as nonflammability, low toxicity, and selective solubility in addition to excellent stability, so they can be used to clean objects such as plastics, elastomers, and metals. As a solvent that can effectively dissolve and remove target oils and other dirt without attacking the constituent materials, it can be used to clean films, magnetic tapes, electronic and electrical equipment such as printed circuit boards, relays and motors, and optical equipment such as lenses and watches. It is widely used for cleaning precision equipment, finishing cleaning in plastic processing, dry cleaning, etc.

As mentioned above, Freon 113 solvents are generally highly stable, so under normal usage conditions, it is not necessary to add stabilizers found in chlorinated solvents such as tetrachlorethylene, trichlorethylene, or 1,1°1-trichloroethane. is necessary.

However, if a large amount of water is mixed into the solvent when it comes into contact with various metals such as iron, aluminum, copper, and brass, it becomes difficult to maintain such stability for a long period of time, and the solvent is degraded by hydrolysis. Not only does it deteriorate, but the generated acid may corrode the object to be cleaned or the cleaning machine.

These trends are more pronounced for the mixed solvent than for the single Freon 113 solvent.

By the way, as a method to improve the stability of Freon 113-based solvents, conventionally, primary and secondary alkyl amines (Special Publications
0-13724), a mixture of propylene oxide and nitromethane (Japanese Patent Publication No. 45-12488),
Halogenated benzene (Japanese Patent Publication No. 45-32048)
Various stabilizers have been proposed, such as benzimidazole compounds (Japanese Patent Publication No. 49-37031) and mixtures of epoxides and olefins (Japanese Patent Publication No. 37031-1982).

However, these stabilizers were not necessarily satisfactory under severe conditions where water and metal coexist.

Therefore, the present inventors investigated various stabilizers to improve the stability of Freon 113 and its mixed solvent, and found that nitroalkanes having 1 to 6 carbon atoms such as nitromethane and/or nitroethane (hereinafter referred to as The inventors have discovered that a surprisingly high stabilizing effect can be achieved by adding a combination of both compounds (referred to as nitro compounds) and glycidol, and have arrived at the present invention.

That is, the present invention is a novel stabilization method characterized by adding a nitro compound, preferably nitromethane and/or nitroethane in combination with glycidol, to Freon 113 and its mixed solvent. The object of the present invention is to provide a method for stabilizing Freon 113 and its mixed solvent, which can maintain good stability even under severe conditions such as the coexistence of water.

When a nitro compound or glycidol is added to Freon 113 or a mixed solvent thereof, the stabilizing effect is small; or it does not exhibit any stabilizing effect at all, whereas simply adding them in combination results in a significant stabilizing effect. The fact that a stabilizing effect was observed is a completely unexpected result.

In the present invention, the proportion of the stabilizer added to Freon 113 and its mixed solvent is such that the nitro compound is o, oi to 3.0% by weight, preferably 0.1 to 2.0% by weight. Weight%, glycidol 0.001
~0.5% by weight, preferably 0.01-0.2% by weight, respectively, are suitable.

If the amount of the stabilizer added is less than the above range, no stabilizing effect will be observed, and if it is more than the above range, the properties of Freon 113 and its mixed solvent will be adversely affected, which is not preferable.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 9 Each combination of the nitro compound and glycidol shown in Table 1 was added to a glass container (inner diameter: 45mm, depth: 90mm) in an amount equivalent to 0.3% by weight to 30g of Freon 113 or its mixed solvent. of water (1.5% by weight in the case of a mixed solvent of Freon 113 and Improper Tool), put in a sufficient layer of metal pieces (40 mr IL x 20 m x 2 spaces), then seal tightly and leave at room temperature for 15 days. An immersion test was conducted.

The above results are shown in Table 1. Comparative Examples 1 to 8 0 to Freon 113 or its mixed solvent without adding stabilizer
．． Example 1 by adding water equivalent to 3% by weight (1.5% by weight in the case of a mixed solvent of Freon 113 and isopropanol)
Comparative Examples 1, 2, 6, and 7.8 in Table 2 show the results of tests conducted in the same manner as in Examples 1 to 9.

In addition, 0.3% was added to each of Freon 113 or a mixed solvent thereof to which a nitro compound or glycidol was added as a stabilizer, and Freon 113 or a mixed solvent thereof to which a nitro compound and alkylene oxide were added in combination.
Comparative Examples 3 and 4.5 in Table 2 show the results of a test in which water was added in an amount equivalent to % by weight.

Note that butylene oxide was added as the alkylene oxide.

Examples 10 to 19 A combination of a nitro compound and glycidol was added to a glass eggplant flask (inner volume 300 mA') equipped with a reflux condenser, and Freon 113 or its mixed solvent 20 was added.
Add water equivalent to 0CC and 0.3% by weight (1.5% by weight in the case of a mixed solvent of Freon 113 and Improper Tool), and place a sufficient layer of metal pieces (40 mm x 20 mrn x 2 mm).
) were installed in the gas phase and liquid phase, respectively, and heated to 48℃ at about 55℃.
The mixture was heated to reflux for an hour.

The above results are shown in Table 3.

Comparative Examples 9 to 16 0 to Freon 113 or its mixed solvent without adding stabilizer
．． Example 1 by adding water equivalent to 3% by weight (1.5% by weight in the case of a mixed solvent of Freon 113 and isopropanol)
Comparative Examples 9, 10, 14, 15゜16 in Table 4 show the results of tests conducted in the same manner as those for Nos. 0 to 19.

In addition, an amount of water equivalent to 0.3% by weight was added to each of Freon 113 and its mixed solvent to which a nitro compound or glycidol was added individually as a stabilizer, and Freon 113 and its mixed solvent to which a nitro compound and alkylene oxide were added in combination. The results were shown in Comparative Examples 10 and 11 in Table 4.

Note that butylene oxide was added as the alkylene oxide.

Claims (1)

[Claims] 11,1.2-) Lichloro-1.2.1,1,2-Trichloro-1 characterized by adding a nitro compound and glycidol to a 2-trifluoroethane solvent
22-1 Method for stabilizing refluoroethane solvent.