JPS61189237A - 1,1,1-trichloroethane composition - Google Patents

Abstract

PURPOSE:To stabilize the titled substance useful as a de-fatting detergents for various metallic parts, containing at least two stabilizers selected from an ether, an alcohol, a nitroalkane and an epoxide and a gallic ester. CONSTITUTION:The titled composition containing at least two stabilizers selected from the group consisting of an ether, an alcohol, a nitroalkane, and an epoxide and a gallic ester. The amounts of the stabilizers added are usually 0.1-9wt% ether such as dimethoxymethane, etc., 0.1-9wt% alcohol such as isobutyl alcohol, 0.01-3wt% nitroalkane such as nitromethane, etc. and 0.01-2wt% epoxide such as propylene oxide, etc. based on a 1,1,1-trichloroethane composition, the total amounts of the two stabilizers are 1-10wt%, and the mount of the gallic ester used is about 0.00005-0.05wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to stabilized 1,1,1-trichloroethane compositions.

More specifically, at least two stabilizers selected from the group consisting of ethers, alcohols, nitroalkanes, and epoxides and gallic acid esters are added to 1,1,1-trichloroethane in combination. The present invention relates to a stabilized 1,1,1-trichloroethane composition having the following characteristics.

[Prior art]

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

However, 1,1.1-)lichloroethane is susceptible to decomposition reactions induced by other chlorinated hydrocarbon solvents, such as trichlorethylene, and various metals such as 14f, rs, aluminum, zinc, and iron. It has disadvantages that are easy to cause.

This 1.1. i-) The decomposition reaction of lychloroethane upon contact with metal varies depending on the type of metal, but
Especially in the case of aluminum, in the presence of aluminum, 1.1.1-) Lichloroethane decomposes in a chain reaction while generating hydrogen chloride even at room temperature, and eventually corrodes the aluminum severely and turns black. It turns into a tar-like substance.

Therefore, when using 1,1.1-)lichloroethane for cleaning various metal parts, the decomposition reaction of 1,1.1-)lichloroethane induced by those metals is suppressed, and the cleaning target and i. Does not corrode the cleaning equipment; 1. i-
) Stabilization of lychloroethane is an essential requirement, and it has been proposed that many stabilizers such as ethers, nitriles, nitroalkanes, alcohols, ketones, and epoxides be added alone or in combination of two or more. has been done.

However, these stabilizer formulations have suppressed catalytic decomposition with various metals. ) is not necessarily satisfactory under conditions of repeated use over a long 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.

Phenol ever to improve this point.

Attempts have also been made to use phenols such as cresol, thymol, 2,6-tert-butyl p-cresol, methoxyphenol, and salicylic acid esters, aliphatic or alicyclic amines, and the like.

However, these are not very effective when added in small amounts, and when added in large amounts to obtain a sufficient effect, various problems such as coloring and odor of the liquid, formation of insoluble substances, and evaporation residues occur.

Particularly in recent years, items to be cleaned have become more diverse, and are not limited to metal products. For example, in cleaning ceramics and resin products, dry cleaning clothes, etc., coloring of the liquid with these stabilizers may cause back contamination of the items being cleaned. occurs and becomes 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-) Lichloroethane To prevent corrosion of objects to be cleaned and cleaning machines, etc., even if used at high temperatures for long periods of time,
Another object of the present invention is to provide a stabilizer suitable for preventing colored contamination of objects to be cleaned.

[Summary of the invention]

Therefore, the present inventors focused on the above points and conducted various studies, and as a result, the results were as follows: 1,1.1-)! The present invention was completed by adding a combination of at least two stabilizers selected from the group consisting of ethers, alcohols, nitroalkanes, and epoxides and gallic acid esters to J chloroethane.

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

1.4-dioxane, 1. He5-trioxane, 1.3
-Dioxolane, etc.

In addition, as the alcohol, aliphatic alcohols containing 1 to 6 carbon atoms in the molecule are preferable, and in particular, isobutyl alcohol, 5ea-butyl alcohol, tar
t-butyl alcohol, tθH-amyl alcohol, 2
-Methyl-3-butyn-2-ol and the like are preferred.

As the nitroalkanes, nitromethane, nitromethane and nitropropane are effective.

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

In addition to the above-mentioned known stabilizers, gallic acid esters must be added as stabilizers. Examples of the gallic acid esters include methyl gallate, ethyl gallate, propyl gallate, and amyl gallate.

Alkyl gallic acid esters such as lauryl gallate are effective.

The amounts of the above stabilizers added vary depending on the conditions of use, but are usually 1 to 9 wt% of ethers α and 11 to 9 vt% of alcohols to the 1,1.1-)lichloroethane composition.
, nitroalkanes α01-3 wt%, epoxides [L01-2 wt%, and the total amount of at least two or more of these known stabilizers is used in the range of 1-10 wt%, and ester gallates is o, o o o
About 5 wt% of O s to fl O is used. The more suitable addition amount for practical use is the total amount of the above-mentioned known stabilizers, or 1.5 to 5.
In wt%, gallic acid esters α0001 to α005
It is 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, gallic acid esters, which are especially effective when added in small amounts, have the effect of suppressing to some extent the production of acid components in 1.1.1-) Lichloroethane even when used alone. The Friedel-Crafts type decomposition reaction cannot be prevented at all, and the composition of the present invention provides excellent stabilization due to a large synergistic effect for the first time, improving the overall practical performance of 1,1゜1-trichloroethane. It is something that will be done. Furthermore, attempts have been made to add 2,6-sheeter to the composition of the present invention.
It is also possible to use stabilizers other than phenols, such as t-butyl-p-cresol.

〔Effect of the invention〕

The 1,1,1-trichloroethane composition obtained by the present invention is suitable for use in steam cleaning used at high temperatures, various cleaning methods used during distillation recovery, dry cleaning, etc., but it can also be used in other industrial solvents. It is a suitable composition that can be widely used as a cleaning agent, does not corrode objects to be cleaned, cleaning machines, etc., and does not cause coloring or contamination 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 chloroethane was evaluated using the following three test methods.

Note that 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 usability at high temperatures. Furthermore, Test-3 is a stability test against color change of the liquid.

<Test-1> A sample soi and an aluminum test piece whose surface was cleaned (material: J.K. 5H4000,
A1100F, dimensions: 501ntnX 50wa
m x 1 m) IJ plate (90 mm φ x 20 s
ia) and scratch the surface of the aluminum piece by rubbing it with a knife.

The scratches are approximately Q in depth and 1 am thick, spaced approximately 3 times apart.
After this, three pieces were attached at right angles to this, and after 10 minutes, the state of corrosion of the scratches on the aluminum piece was observed.

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

◎...No change at all.・ 0: Some parts are slightly discolored.

△・・・Slightly corroded.

×: Significant corrosion.

Test-2> The test is carried out in accordance with the method specified in the accelerated oxidation test of J.Eng. SK 1600.

500 equipped with a reflux condenser and an oxygen introduction tube for sample 200d
- Place in a hard glass Erlenmeyer flask.

Two pieces of mild steel (
Immerse one side (dimensions: 211 JI x 6 x 20 x 20 x 21 x 21 x 21 x 20 x 21 x 20 x 21 x 20 x 40 x 10 x 10 x 10 x 10 x 100 x 100 x 100 x 100 mm) of the pipe (material: J Engineering SG 4501.5200) into the sample, and connect the other side ((dimensions: 21 uI x 13 x 50 x) to the oxygen introduction tube. Hang it in the vapor layer above the sample liquid level.

Adjust the tip of the oxygen introduction tube (3ms + φ) so that it is within 6W from the bottom of the Erlenmeyer flask, and pass water-saturated oxygen bubbles at room temperature at a rate of 10 to 12 bubbles per minute using a 150W frosted light bulb. 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.

◎...No change at all.

○...The gloss is slightly reduced.

△...Slight corrosion is observed.

×...Significant corrosion.

Test-3> Transfer 100 ml of the sample to a hard glass test tube with a stopper (30 m
mφ x 250 mm) and irradiated it with light using a 100 W mercury lamp located 9 m from the side of the test tube in a constant temperature water bath at 30°C. After 18 hours, the sample was taken out and the chromaticity (APHA) was measured. did.

Note that APHA was determined based on the chromaticity of J-K5-KOlol.

Examples 1-10. Comparative Examples 1 to 19 1, 1.1-) Regarding the results of evaluating the stability of lychloroethane using the above three test methods, Examples 1 to 1
0 is shown in Table-1, and Comparative Examples 1 to 19 are shown in Table-2.

Claims (1)

[Claims] A stabilized 1,1,1-trichloroethane composition comprising at least two stabilizers selected from the group consisting of ethers, alcohols, nitroalkanes, and epoxides and gallic acid esters. .