JPS5885826A - Stabilization method of methylene chloride - Google Patents

Abstract

PURPOSE:To prevent the decomposition of methylene chloride and further the corrosion of metal in the vapor and liquid phase parts in the washing step of the metal with steam, by adding a combination of methanol, an aliphatic amine, epoxide and phenol to the methylene oxide. CONSTITUTION:0.01-1.0wt% methanol, 0.005-0.5wt% aliphatic amine, e.g. diisobutylamine, 0.01-1.0wt% epoxide, e.g. propylene oxide, and 0.001-0.05wt% phenol, e.g. eugenol, are added to prevent the decomposition of methylene chloride. In particular, a stabilizer for the methylene chloride used in washing metal with steam is required to satisfy the above-mentioned combination, and the absence of even one component of the combination remarkably reduces the effect thereof.

Description

[Detailed description of the invention] This book concerns the method for stabilizing methylene chloride.

Specifically, it is a method for stabilizing methylene chloride in which methanol, 11-aliphatic amines, 4-oxides, and phenols are added to methylene chloride.

Chlorinated hydrocarbons are widely used as general Kll and #l agents. In general, pure chlorinated hydrocarbons are relatively stable compounds, but when industrially produced products come into contact with gold under the influence of light, air, moisture, oil, heat, etc., chlorine Hydrocarbons are divided into 4 parts. For this purpose, various stabilizers have been developed and used singly or in combination. However, since the decomposition mechanism of chlorinated hydrocarbons differs depending on the species per ml, there is no stabilizer that is effective against all chlorinated hydrocarbons, and we have developed combinations of stabilizers to be used depending on the type of chlorinated hydrocarbon. For example, even if stabilizers for unsaturated chlorinated hydrocarbons such as chlorethylene and trichlorethylene are used for saturated chlorinated hydrocarbons such as dichloroethane and trichlorethane, no stabilizing effect can be expected. Can not. Even among saturated chlorinated hydrocarbons, methyl chloroform, dichloroethane, [
It is not possible to use the same stabilizer because the decomposition mechanisms are different for each type of stabilizer, such as 7. Therefore, at present, appropriate combinations of stabilizers are developed depending on the type of each chlorinated hydrocarbon.

Among the above-mentioned chlorinated hydrocarbons, methylene chloride is relatively stable and has good stability compared to other chlorinated hydrocarbons, so there are few fields where it is necessary to add a stabilizer. However, when the methylene chloride is used as a solvent for steam cleaning of metals, the methylene chloride tends to decompose to some extent and the decomposed products tend to cause corrosion of metals.

We have conducted intensive research to develop a stabilizer that can stabilize methylene chloride during steam cleaning of metals with methylene chloride. As a result, the combination of methanol, aliphatic amines, nixides, and phenols very effectively prevents the decomposition of methylene chloride during steam cleaning of the metals, and when steam cleaning the metals, the gas phase and The present invention was completed by discovering that it is possible to prevent corrosion of metals present in the enemy phase.

The present invention is a method for stabilizing methylene chloride by adding methanol, aliphatic amines, epoxides, and phenols to methylene chloride.

The aliphatic amines used in the present invention may be any known aliphatic amines used as stabilizer components for other chlorinated hydrocarbons without particular limitation. In general, diisoalkylamines such as guitubutylamine and diinzolobylamine are the most effective, and are suitable because they do not have to worry about coloring caused by methylene chloride.

In addition, as the epoxides used in the present invention, known ones can be used without particular restriction. For example, propylene oxide,
Butylene oxide and the like are commonly used.

Furthermore, the phenols used in the present invention include, for example, phenol, thymol, catechol, noyalacresol, eugenol, and eugenol.

The amount of the stabilizer added in the present invention varies depending on the field of use of methylene chloride, the conditions of use, the type of stabilizer, etc., and is not limited to any particular part, but may be determined in advance as necessary.

Generally methanol is relative to methylene chloride.

0.00/~2.0% by weight, preferably o, oi~/,
0 parts by weight, and the aliphatic amines are O0θOno~ko, θweight t-, preferably Fio, oos~ with respect to methylene chloride.
It is sufficient to select from a range of -0.5 weight. Furthermore, it is sufficient to select from the range of epoxides FiO, 00/~ko, O weight-, preferably from the range of liO, 01~i, 0 weight iis. Yet again.

Phenols are O0θO7~O07 weight, preferably Fi
It may be added within the range of o, θO/ to o, os weight 5-.

Some of the stabilizer components in this invention are known as methylene chloride and other chlorinated hydrocarbon bulk stabilizers in combination with other components. However, as is clear from the table and the Examples and Comparative Examples described below, I# as a stabilizer for methylene chloride used for steam cleaning of metals can only be partially effective when the above-mentioned combination of components of the present invention is satisfied. However, when one component of this combination is missing and the round string combination is used, the reduction effect is significantly reduced. *It is not yet clear how the combination of the above-mentioned components of the cutout exhibits such an excellent stabilizing effect.

In order to explain the present invention more specifically, the present invention will be described below with reference to Examples and Comparative Examples, but the book is not limited to these Examples.

Examples and Comparative Examples Methylene chloride 2! ;Hitori shown in Table 1 for 081,
and an amount of stabilizer, and water to prepare the test solution.
1111IL, the test solution was placed in a 300 d round bottom flask, and a /QQMI Soxhlet extractor was attached to the round hawk flask. Similarly, inside the round-bottomed flask and the Noxleni extractor, there were zinc pieces with well-polished surfaces. A stability test of methylene chloride was carried out by heating the above round bottom flask on a water bath and boiling and refluxing methyl chloride for S days continuously. The test solution was extracted with distilled water, and the resulting aqueous phase was measured for -, and the surface condition of the zinc pieces in the round bottom flask and Soxhlet extractor was measured.
The results are also shown in the Ig/Table. The surface condition of the zinc piece was evaluated based on the following criteria.

O: The test piece did not change at all.

0: Cloudiness 9 is observed in a part of the test piece.

'Δ: Clear corrosion is observed in a part of the test piece.

X: Corrosion is observed over the entire surface of the test piece.

Claims (1)

[Claims] Adding methanol, aliphatic amines, tetraoxides, and phenols to methylene chloride is I! # Method for stabilizing methylene chloride as an image.