JPS61191629A - Stabilized 1,1,1-trichloroethane composition - Google Patents

Abstract

PURPOSE:To provide the titled composition containing a specific stabilizer, a phenolic compound and a thiuram compound, usable for a long period at a high temperature without causing the corrosion of the washing material and the object to be cleaned nor causing the coloring of the object, and suitable for the dry cleaning of clothes. CONSTITUTION:A 1,1,1-trichloroethane composition is stabilized by the addition of (A) two more more kinds of stabilizers selected from (i) 0.1-9(wt)% ethers such as 1,4-dioxane, (ii) 0.1-9% alcohols such as sec-butyl alcohol, (iii) 0.01-2% nitroalkanes such as nitromethane, and (iv) 0.01-2% epoxides such as 1,2- butylene oxide, and (B) an assistant stabilizer consisting of 0.00001-0.1% phenols such as thymol and 0.00001-0.005% thiurams such as tetramethyl-thiuram monosulfide. The composition is useful for various cleaning systems and industrial solvents for the cleaning of metallic products and various industrial materials at a high temperature by vapor-washing or distillation recovery method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to stabilized 1,1.1-)lychloroethane compositions.

More specifically, 1.1.1-trichloroethane is mixed with a small amount of a stabilizer selected from the group consisting of 1-ethers, alcohols, nitroalkanes, and epoxides (combined with 2-trichloroethane, 7-enols, and thiurams). Stabilized 1, 1.1-) characterized by the addition of
The present invention relates to IJ chloroethane compositions.

[Prior art]

1,1.1-Trichloroethane has excellent dissolving power for various oils, is nonflammable, and is also less toxic to the human body than other chlorinated hydrocarbon solvents, so it can be used for degreasing and cleaning of various metal parts. Widely used as a solvent, dry cleaning solvent and other industrial solvents.

However, unlike other chlorinated hydrocarbon solvents such as trichlorethylene and perchlorethylene, t 1.1- )lychloroethane is aluminium-based.

It has the disadvantage of being susceptible to decomposition reactions induced by various metals such as zinc and iron.

This 1.1. The decomposition reaction of L-trichloroethane when it comes into contact with metal varies depending on the type of metal, but it is particularly noticeable in the case of aluminum.1.1.1-) Lichloroethane generates hydrogen chloride even at room temperature. However, the decomposition progresses in a chain reaction, eventually severely corroding the aluminum and leaving a blackish brown tar.
Changes into a liquid substance.

Therefore, 1.1.1-) When dichloroethane is used for cleaning various metal parts, the decomposition reaction of 1,1.1-trichloroethane induced by gold tliK is suppressed, and the cleaning items and cleaning equipment are 1.1 To prevent corrosion of
．． Stabilization of 1-trichloroethane is an essential requirement;
Traditionally, ethers, nitriles, nitroalkanes,
It has been proposed to add a number of stabilizers such as alcohols, ketones, and epoxides singly or in combination of two or more.

However, these stabilizer formulations suppressed catalytic decomposition with various metals1, 1.1-) Even with IJ dichlorothane, it is difficult to use it at high temperatures (boiling point) for long periods of time, such as various cleaning methods and steam cleaning methods that are used while recovering by distillation. This is not necessarily satisfactory under conditions of repeated use over a period of time.

That is, even if there is no problem during short-term use, during long-term use, the acid content generated in 1.1.1-) dichloroethane gradually accumulates, causing corrosion of the objects to be cleaned and the cleaning equipment.

In order to improve this point, attempts have been made to use 7 enols, amines, etc. in combination, but these also have little effect when added in small amounts, and in order to obtain a sufficient effect, it is necessary to add large amounts. This causes problems such as coloration and odor of the liquid, the formation of insoluble substances, and evaporation residues.

Particularly in recent years, the objects to be cleaned have diversified and are not limited to metal products. For example, in the cleaning of ceramics and resin products and the dry cleaning of clothing, the coloring of the liquid with these stabilizers is used to reverse dye the objects to be cleaned. This results in a fatal problem.

[Problem that the invention seeks to solve]

That is, the present invention is used for cleaning various industrial materials including metal products, dry cleaning of clothing, etc.
1.1-) It is an object of the present invention to provide a suitable stabilizer for dichloroethane so that it does not corrode the objects to be cleaned or cleaning machines, etc. even when used at high temperatures for a long period of time, and prevents the objects to be cleaned from being colored or contaminated. .

[Summary of the invention]

Therefore, the present inventors focused on the above points and conducted various studies, and found that 1.1.1-trichloroethane contains ethers,
A small amount of stabilizer selected from the group consisting of alcohols, nitroalkanes, and epoxides (both 1, i, and 1- stabilized by adding two types of stabilizers) is added to the IJ chloroethane composition with a small amount of phenols. By adding a combination of thiurams (1.1.1-)
They discovered that the stability of dichloroethane could be significantly improved and completed the present invention.

As the ethers used in the present invention, chain ethers and cyclic ethers having two or more oxygen atoms in the molecule are effective,
For example, dimethoxymethane, 1,2-dimethoxyethane,
2-methoxyethanol.

1.4-dioxane, 1. \5-Trio Φ Sun, 1.3
-Dioxolane, etc.

In addition, as the alcohol, aliphatic alcohols containing 1 to 6 carbon atoms in the molecule are desirable, especially diisobutyl alcohol, 5ec-7'yl alcohol, tart-
Butyl alcohol, tert-amyl alcohol, 2
-Methyl-3-butyn-2-ol and the like are preferred.

Effective nitroalkanes include nitromethane, nitroethane, and nitropropane.

Epoxides are not particularly limited, but preferred examples include propylene oxide, 1,2-butylene oxide, epichlorohydrin, and methyl glycidyl ether.

In the present invention, in addition to the above stabilizers, phenols and thiurams must be added.

As the phenols used in the present invention, monohydric and dihydric phenols and their derivatives are effective, such as phenol, thymol, z6-di-tert-7''thyl-p
-Cresol, methoxyphenol, catechol, 2.
Examples include 5-di-tert-amylhydroquinone, and more preferably 2,6-di-tert-butyl-p-cresol.

Furthermore, as the thiurams, tetramethyl-thiuram monosulfide, tetramethylnithiuram cisulfide, tetraethyruthiuram disulfide, etc. can be used.

The amount of the above stabilizer added varies depending on the conditions of use, but usually 1.1.1-) 0.00% of the ethers are added to the dichloroethane composition. ．． 1-9wt%, alcohol 11-9wt1
．． Nitroalkanes α01~s wt'4 @ epoxides 1101~2 wtl, and the total amount of at least two of these main stabilizers is in the range of 1 to 10 wt%, and the co-stabilizer phenol The kind is (LO
OO1~(L 1 wtes and thiurams are 100
005~(LO1wtts is used).

Practically speaking, the more suitable amount of stabilizers to be added is that the total of the above main stabilizers is 1.5 to 5 wtl, and the amount of phenols (LOO05
~(101wtl, f urams are α0001~lo0
Al at 5 wt%.

If the amount of these stabilizers added is outside the above range, the effects of the present invention cannot be achieved.

In the present invention, phenols and thiurams, which are particularly effective when added in small amounts, are 1.1.1-
)Although the production of acid components in dichloroethane can be suppressed to some extent, it is caused by metals such as aluminum7.
The U-Delkraft type decomposition reaction cannot be prevented, and excellent stabilization can be obtained only by using it in combination with the main stabilizer of the present invention due to the large additive effect. The performance is perfect. It is also possible to use other stabilizers in combination with the composition of the present invention.

〔Effect of the invention〕

The 1, 1.1-) dichloroethane composition obtained by the present invention is suitably used for steam cleaning used at high temperatures, various cleaning methods used during distillation recovery, dry cleaning, etc. It is a suitable composition that can be widely used as a cleaning agent and does not corrode objects to be cleaned or cleaning machines, etc., and does not cause coloring or staining of objects to be cleaned.

〔Example〕

Next, the present invention will be explained in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

1, 1.1-) The stability of IJ dichlorothane was evaluated using the following three test methods.

Test-1 is a stability test against Friedel-Crafts type condensation decomposition caused by aluminum, and Test-2 is a stability test against oxidative decomposition, which is a measure of long-term use at high temperatures. Furthermore, Test-5 is a stability test against color change of the liquid.

Test-1〉 Sample 50- and a surface-cleaned aluminum test piece (material: H40 from JIS
00, A 1100F, dimensions: 50 mX 50 a
m X I IuI) in a Petri dish (90fiφ×201
11ml) and scratch the surface of the aluminum piece with a knife.

The scratches were approximately 5 deep (Ll-) at approximately equal intervals, and 3 more at right angles to this, and after 10 minutes,
Observe the state of corrosion on the scratches on the aluminum piece.

The criteria for judging scratches on aluminum pieces shall be marked as shown below.

◎...No change at all.

○: Partially discolored.

Δ... Slight corrosion.

X: Significant corrosion.

Test-2> The test is carried out in accordance with the method specified for the 160G accelerated oxidation test in J Engineering 8.

Sample 200-500 equipped with a reflux condenser and oxygen inlet tube
- Place in a hard glass Erlenmeyer flask.

One (dimensions: 2 w x 6 al x 20 m) of two mild steel pieces (material: JIS G 4051. El 200) that had been thoroughly polished, thoroughly washed, and dried was immersed in the sample, and the other (dimensions: 21 as x 15 aua
X 50 m) is connected to the oxygen introduction tube and suspended in the vapor layer above the sample liquid level.

Adjust the tip of the oxygen introduction tube (3 mm φ) so that it is within 6 mm from the bottom of the Erlenmeyer flask, and let water-saturated oxygen bubbles at room temperature pass through at a rate of 10 to 12 bubbles per minute.
Heat with a 50 W frosted light bulb and adjust the flow rate of cooling water so that the sample condenses at less than half the height of the reflux condenser.

Refluxing was carried out for 48 hours, and after cooling to room temperature, the mild steel piece was taken out and its appearance was inspected, and at the same time, the acid content generated in the test liquid was measured by titration.

The appearance criteria for mild steel slabs are shown as follows.

◎・・・Complete (No change.

○...The gloss is slightly reduced.

Δ...Slight corrosion is observed.

×...Significant corrosion.

Test-3〉 Sample 100- was placed in a hard glass test tube with a stopper (30III
Iφ O APHA is: fXB-K (defined according to the chromaticity of MOI.

Examples 1-8. Comparative Examples 1 to 20 1, 1.1-) +7 Regarding the results of evaluating the stability of chloroethane using the above three test methods Example 1
-8 are shown in Table-1, and Comparative Examples 1-20 are shown in Table-2.

Claims (1)

[Claims] A stabilized 1,1,1-trichloroethane composition characterized by containing at least two stabilizers selected from the group consisting of ethers, alcohols, nitroalkanes, and epoxides, and phenols and thiurams. thing.