JPS588364B2 - Method for stabilizing 1,1,1↓-trichloroethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stabilizing 1,1,1-trichloroethane.

More specifically, 1.1-1-, which is characterized in that allyl glycidyl ether is added as a co-stabilizer when 1.1.1-trichloroethane is stabilized with a stabilizer.
This invention relates to a method for stabilizing trichloroethane.

1,1,1-Trichloroethane is used in many fields, mainly for degreasing and cleaning metals, due to its excellent properties of high dissolving power for oils and fats and low toxicity.

However, 1,1,1-trichloroethane is a saturated chlorinated hydrocarbon and has a unique molecular structure, and its stability and reactivity towards metals are 1.
There is a significant difference between 1,1-trichloroethane and trichlorethylene and perchlorethylene, which are used for similar purposes. In particular, when it comes into contact with aluminum and aluminum alloys, a decomposition reaction occurs immediately accompanied by the generation of hydrogen chloride gas, and at the same time It has a defect that severely corrodes aluminum and aluminum alloys.

For this reason, commercially available 1,1,1-trichloroethane usually contains several types of stabilizers in a total amount of 3 to 6 wt% based on 1,1,1-trichloroethane.
The reality is that it prevents corrosion against aluminum and aluminum alloys, and at the same time is stabilized against other metals such as iron, copper, and zinc.

Conventionally, many methods for stabilizing 1,1,1-trichloroethane have been proposed.

Typical examples include the addition of either cyclic or linear ethers such as 1,4-dioxane, 1,5-dioxolane, and 1,2-dimethoxyethane mainly for the purpose of corrosion protection for aluminum and its alloys. In addition, nitroalkanes such as nitromethane, nitroethane and 2-nitropropane, alcohols, amines, vic-monoepoxides, antioxidants and the like are often added as co-stabilizers.

However, even these combinations do not necessarily provide sufficient stability.

Further, although the use of phenyl glycidyl ether as a co-stabilizer is disclosed in Japanese Patent Publication No. 1047/1983, its effect is not sufficient.

As a result of research, the present inventors have found that by adding allyl glycidyl ether as a co-stabilizer in combination with other stabilizers, the desired 1,1,1-trichloroethane can be sufficiently stabilized. discover what can be achieved,
This has led to the present invention.

The allyl glycidyl ether of the present invention has an epoxide group and an ether group in its molecular structure, and not only has a stabilizing effect better than that of ordinary vie-monoepoxide, but also has a phenyl glycidyl ether. It has been found that it exhibits a much better stabilizing effect than glycidyl ether.

The amount of allyl glycidyl ether used as a co-stabilizer in the present invention is preferably 0.01 to 0.5 wt% based on 1.1.1-trichloroethane.
If the amount is less than 0.01 wt%, the effect cannot be maintained;
If the amount is more than 5 wt%, there is no problem in terms of effectiveness, but it is not economical because a greater effect cannot be expected.

The allyl glycidyl ether of the present invention may also contain other stabilizers, such as cyclic or linear ethers, 1,4-dioxane, 1
- It can be used in combination with 3-dioxolane, 1,2-dimethoxyethane, nitroalkanes, etc. Among them, preferred combinations are as follows.

The composition of the stabilizer for aluminum and its alloys is as follows: 3-methyl-1-butyn-3-ol and nitromethane are mixed into 3-methyl-1-butyn-3-ol to 1,1,1-trichloroethane. 2.0-5. It is desirable that the total amount of 3-methyl-1-butyn-3-ol and nitromethane be 3.0 to 5.0 wt%.

In this case, it is not economical to increase the amount of stabilizer added more than necessary, and it also promotes corrosion of metals other than aluminum.

1,1,1-trichloroethane to which 3-methyl-1-butyn-3-ol and nitromethane are added within the above range shows a nearly satisfactory stabilizing effect on aluminum and its alloys, but on iron, Satisfactory effects cannot be obtained against corrosion of copper, zinc, brass, etc.

By adding allyl glycidyl ether to this in an amount of 0.01 to 0.5 wL% based on 1.1.1-trichloroethane, the above drawbacks can be overcome.

Furthermore, by adding 1,2-butylene oxide as an acid acceptor, which is a known substance generally used as a stabilizer for 1,1,1-trichloroethane, in addition to the above three components, the effect can be further increased. It can be tightened.

The present invention will be explained below with reference to Examples.

Examples Stability against various metals Mild steel pieces, copper pieces, zinc pieces, and brass pieces (each 13 x 75 mm) with sufficiently polished surfaces were used as test pieces.

A 150 ml Erlenmeyer flask is charged with 50 ml of 1,1,1-trichloroethane to which a predetermined amount of stabilizer has been added, and one of each of the above test pieces is placed in the flask.

The specimen is placed in a flask so that both gas and liquid phases are present.

Attach a reflux condenser to the flask, heat it with a 100W light bulb, keep it in a boiling reflux state for 24 hours, and then observe the condition of the metal piece.

The condition of the metal piece was indicated by the following judgment symbol.

[Judgment symbol]

A No change B Discoloration or loss of luster C Corrosion is observed

Claims (1)

[Claims] 1. Stabilization of 1,1,1-trichloroethane characterized by adding 3-methyl-1-butyn-3-ol, nitromethane and allyl glycidyl ether to 1,1,1-trichloroethane method. 2 The amount of allyl glycidyl ether added is 1・1・1−
The method according to claim 1, wherein the amount is 0.01 to 0.5 wt% based on trichloroethane. 3 2.0 to 5.0 wt% of 3-methyl-1-butyn-3-ol and 0.1 to 2.0 wt% of nitromethane based on 1.1.1-trichloroethane. Owt%, and the total amount of both is 3.0 to 5. The method according to claim 1, wherein O wt % and allyl glycidyl ether are 0.01 to 0.5 wt %. 4 3-methyl-1- in 1,1,1-trichloroethane
7" A method for stabilizing 1,1,1-trichloroethane, characterized by adding tin-3-ol, ditromethane, 1,2-butylene oxide, and allyl glycidyl ether. 5 Addition amount of allyl glycidyl ether is 1・1・1−
5. The method according to claim 4, wherein the amount is 0.01 to 0.5 wt% based on trichloroethane. 6 2.0 to 5.0 wt % of 3-methyl-1-butyn-3-ol and 0.1 to 2.0 wt % of 3-methyl-1-butyn-3-ol and 0.1 to 2.0 wt % of 1.1.1-trichloroethane. %, and the total amount of both is 3.0 to 5.0 wt%, and the allyl glycidyl ether is 0.01 to 0.5 wt%.