JPH07330692A - Stabilization of monoethanolamine - Google Patents

Abstract

PURPOSE:To industrially and profitably stabilize the amine so that the deterioration of the amine can extremely be reduced, even when a solvent containing the amine is used as a detergent for a long time under heating, by adding an oxidation-preventing agent to the (solvent containing) monoethanolamine. CONSTITUTION:Monoethanolamine or a solvent containing the monoethanolamine is mixed with an antioxidizing agent to stabilize the amine. The antioxidizing agent includes 2,6-di-t-butyl-p-cresol and butylated hydroxyanisol, and is preferably added in an amount of 0.0001-0.1 pt.wt. per 100 pts.wt. of the solvent containing the monoethanolamine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stabilizing method for suppressing deterioration of monoethanolamine when using monoethanolamine or a solvent containing monoethanolamine as a detergent.

[0002]

2. Description of the Related Art Conventionally, fluorocarbon and chlorine-based cleaning agents have been used as cleaning agents for cleaning electronic parts, degreasing metal parts and molds and resin cleaning, paint stripping agents, plant cleaning and the like.
However, various developments of non-halogen type cleaning agents have been studied due to environmental problems and the like. Among them, monoethanolamine is rich in detergency and has no toxicity, so that monoethanolamine is used as a detergent alone or as a mixture with other solvents.

[0003]

However, there is a problem that the monoethanolamine is deteriorated when the monoethanolamine or the solvent containing the monoethanolamine is used as a cleaning agent for a long time under heating. An object of the present invention is to provide a method for stabilizing monoethanolamine that solves the above problems.

[0004]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above problems. As a result, it was revealed that the cause of deterioration of monoethanolamine or a solvent containing monoethanolamine under heating for a long time is that monoethanolamine is oxidized by oxygen in the air. Further, they have found that when an antioxidant is added to a monoethanolamine or a solvent containing monoethanolamine and used, deterioration can be remarkably suppressed even when used for a long time under heating, and the present invention has been reached. That is, the present invention is a method for stabilizing a monoethanolamine-containing solvent, which comprises adding an antioxidant to the monoethanolamine-containing solvent.

The present invention will be described in detail below. In the present invention, examples of the solvent of the monoethanolamine-containing solvent include, in addition to water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-
Pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1-nonanol, 3 , 5,5-Trimethyl-1-hexanol, 1-decanol, 1-undecanol, 1-dodecanol, allyl alcohol, propargyl alcohol, benzyl alcohol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methyl Cyclohexanol, 4-methylcyclohexanol, α
-Alcohols such as terpineol and abietinol.

1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-
Butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 2-ethyl-1 , 3-
Polyhydric alcohols such as hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, 2-ethyl-2- (hydroxymethyl) -1,3-propanediol, 1,2,6-hexanetriol .

2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, 2 -Phenoxyethanol, 2- (benzyloxy) ethanol, 3-methyl-3-methoxy-1-butanol, 3-methoxy-1-butanol, 4-methyl-4-methoxy
-2- Pentanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, etc. having an ether bond in the molecule Kind.

Dioxane, furan, tetrahydrofuran, tetrahydropyran, 1,2-dimethoxyethane, 1,2-
Ethers such as diethoxyethane, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether and glycerin ether.

4-methoxy-4-methyl-2-pentanone, 4-
Hydroxy-4-methyl-2-pentanone, 2-methyl-4-pentanone, 2-butanone, ketones such as acetone, 4-methoxy-4-methyl-2-pentyl acetate, 3-methoxy-3
-Esters such as methyl-1-butyl acetate, 3-methoxy-1-butyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate.

Acetonitrile, propionitrile, N, N-
Nitrogen-containing compounds such as dimethylaniline, formamide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N, N-dimethylacetamide, 2-pyrrolidone and N-methylpyrrolidone.

Examples thereof include ureas such as tetramethylurea and 1,3-dimethyl-2-imidazolidone, and sulfur-containing compounds such as thiophene, tetrahydrothiophene, dimethylsulfoxide and sulfolane.

When monoethanolamine and another solvent are also used as a mixed solvent, the mixing ratio may be determined according to the required performance of the solvent, and they can be mixed and used at an arbitrary ratio.

The antioxidants used in the method of the present invention are:
Antioxidants commonly used for petroleum products can be used.
Examples of these are 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole (BHA), 2,6-di-t-
Butyl-4-ethylphenol, stearyl-β- (3,5-di
-t-Butyl-4-hydroxyphenyl) monophenolic antioxidants such as propionate.

2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl-6)
-t-butylphenol), 4,4'-thiobis- (3-methyl-6)
-t-Butylphenol), 4,4'-butylidenebis- (3-methyl-6-t-butylphenol) and other bisphenol antioxidants.

1,1,3-tris- (2-methyl-4-hydroxy-5)
-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6
-Tris- (3,5-di-t-butyl-4-hydroxybenzyl)
Benzene, tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis- [3,3'-bis (4'-hydroxy-3'- t-Butylphenyl) Butyric acid] Polymeric phenolic antioxidants such as glycol esters.

Sulfur type antioxidants such as dilauryl thiodipropionate, dimyristyl thiodipropionate and distearyl thiodipropionate.

Triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene bis- (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, cyclic neopentane tetra Irbis- (octadecylphosphite), tris (nonylphenyl) phosphite, tris (mono and / or dinonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10-dihydro-9-oxa-10- Phosphaphenanthrene-10-oxide, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide , 10- Decyloxy-9,10-
Phosphorus antioxidants such as dihydro-9-oxa-10-phosphaphenanthrene.

Nn-butyl-p-aminophenol, di-sec
-Butyl-p-phenylenediamine, 4,4'-tetramethyl
-Di-aminodiphenylmethane, α-naphthylamine,
Examples thereof include nitrogen-based antioxidants such as N-phenyl-α-naphthylamine, N, N′-disalicylidene-1,2-propylenediamine, phenothiazine and lecithin.

Of these antioxidants, phenolic antioxidants are preferred. The amount of these antioxidants added is 0.0001 to 1 part by weight, preferably 0.001 part by weight, relative to 100 parts by weight of the monoethanolamine or the solvent containing the monoethanolamine.
It is in the range of 05 to 0.5 parts by weight, more preferably 0.001 to 0.1 parts by weight. If the addition amount of the antioxidant is less than this range, the deterioration preventing effect of the monoethanolamine-containing solvent is small, and if it is more than this range, there is a deterioration preventing effect of the monoethanolamine-containing solvent, but the antioxidant is It causes coloring and uses a large amount of expensive antioxidant, which is economically disadvantageous. These antioxidants are
It may be added in advance to a monoethanolamine or a solvent containing monoethanolamine, or may be added on-site when used as a detergent.

[0020]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Example 1 300 m equipped with a stirrer, a reflux condenser, a thermometer and an air inlet tube
l Add monoethanolamine (abbreviated as MEA) 7
0 g, dimethyl sulfoxide 30 g and 2,6-di-t-butyl-p-
30 ppm of cresol (hereinafter abbreviated as BHT) was added, and the mixture was heated at 75 ° C for 5 days while stirring in an air atmosphere. When this liquid was analyzed by ion chromatography, MEA decomposition products were found to be produced in an area ratio of 4 ppm.

Comparative Example 1 Example 1 except that BHT was not used in Example 1.
When an experiment was conducted in the same manner as above, the decomposition products of MEA were
It produced 130 ppm.

Example 2 An experiment was conducted in the same manner as in Example 1 except that butylated hydroxyanisole was used instead of BHT in Example 1, and the decomposition product of MEA was produced in an area ratio of 10 ppm.

Example 3 An experiment was conducted in the same manner as in Example 1 except that 2,6-di-t-butyl-4-ethylphenol was used instead of BHT in Example 1, and the decomposition product of MEA was found to be The area ratio was 8 ppm.

Example 4 2,2'-methylene-bis-in place of BHT in Example 1
An experiment was conducted in the same manner as in Example 1 except that (4-methyl-6-t-butylphenol) was used. As a result, a decomposition product of MEA was produced in an area ratio of 11 ppm.

Example 5 4,4'-Butylidene bis-in place of BHT in Example 1
An experiment was conducted in the same manner as in Example 1 except that (3-methyl-6-t-butylphenol) was used, and as a result, a decomposition product of MEA was produced in an area ratio of 5 ppm.

Example 6 1,1,3-tris- (2-methyl) was used instead of BHT in Example 1.
An experiment was conducted in the same manner as in Example 1 except that -4-hydroxy-5-t-butylphenyl) butane was used, and as a result, a decomposition product of MEA was produced in an area ratio of 6 ppm.

Example 7 Instead of BHT in Example 1, tetrakis- [methylene
-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane was used. An experiment was conducted in the same manner as in Example 1, where the decomposition product of MEA had an area ratio of 8 ppm. Was being generated.

Example 8 An experiment was conducted in the same manner as in Example 1 except that dilaurylthiodipropionate was used instead of BHT in Example 1, and the decomposition product of MEA was 21 ppm in area ratio. .

Example 9 An experiment was conducted in the same manner as in Example 1 except that phenyldiisodecyl phosphite was used instead of BHT in Example 1, and as a result, a decomposition product of MEA was produced in an area ratio of 25 ppm.

Example 10 An experiment was conducted in the same manner as in Example 1 except that di-sec-butyl-p-phenylenediamine was used instead of BHT in Example 1, and the decomposition product of MEA was expressed in area ratio. It produced 31 ppm.

Example 11 An experiment was conducted in the same manner as in Example 1 except that dimethyl sulfoxide was not used in Example 1, and as a result, a decomposition product of MEA was produced in an area ratio of 11 ppm.

Comparative Example 2 When an experiment was conducted in the same manner as in Example 11 except that BHT was not used in Example 11, a decomposition product of MEA was produced in an area ratio of 190 ppm.

[0034]

According to the method of the present invention, even if a monoethanolamine or a solvent containing monoethanolamine is used as a cleaning agent for a long time under heating, deterioration can be remarkably suppressed, which is extremely advantageous industrially and economically. Becomes

Claims (1)

[Claims] 1. A method for stabilizing monoethanolamine, which comprises adding an antioxidant to monoethanolamine or a solvent containing monoethanolamine.