JPH01128945A - Method for stabilizing hydrogen-containing fluorocarbon - Google Patents

Abstract

PURPOSE:To obtain the title stabilized compound, capable of exhibiting effects on storage stability of a polyol contained as a foaming agent and useful as foaming agents, aerosols, etc., by stabilizing a hydrogen-containing fluorocarbon against alcoholic OH using a specific stabilizer. CONSTITUTION:A stabilizer containing hydrocarbons having nitro group, e.g., nitrobenzene or nitropropane, and an epoxy compound, e.g., 1,2-butylene oxide or propylene oxide, is added to a mixture of a hydrogen-containing fluorocarbon, such as dichlorotrifluoroethane, (lower aliphatic halogenated hydrocarbon containing F, halogens other than F and at least one H) with an alcohol to stabilize the hydrogen-containing fluorocarbon against alcoholic OH. Furthermore, the stabilizer can be premixed with polyols in forming a polyurethane foam to suppress decomposition of the hydrogen-containing fluorocarbon during storage without exerting a bad influence in forming.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to lower aliphatic halogenated hydrocarbons (hereinafter simply referred to as hydrogen-containing fluorocarbons) containing fluorine and halogens other than fluorine, and containing at least one hydrogen. This relates to a method for stabilizing the

[Prior art and its problems] It is known that lower aliphatic halogenated hydrocarbons (hereinafter referred to as fluorocarbons) containing fluorine and halogens other than fluorine easily react with alcoholic hydroxyl groups and decompose. CFCs containing only fluorine are stable against alcoholic hydroxyl groups, but other CFCs, such as trichlorofluoromethane and trichlorotrifluoroethane, are said to decompose through reaction to produce aldehydes and ketones. Additionally, completely halogenated fluorocarbons have been pointed out to pose environmental problems to the ozone layer, and there is an urgent need to develop hydrogen-containing fluorocarbons. However, it has been pointed out that hydrogen-containing fluorocarbons are less stable than completely halogenated fluorocarbons, and there is a need to develop a stabilization method.

In general, fluorocarbons are often used in combination with alcoholic hydroxyl groups.9 For example, alcohol is added to solvents to increase solubility, and to propellants to dissolve water-soluble active ingredients. Furthermore, in polyurethane foaming using fluorocarbons as a foaming agent, the fluorocarbons come into contact with polyol, which is a raw material for polyurethane. In addition, there are many occasions when fluorocarbons are used in coexistence with alcoholic hydroxyl groups.

When decomposition of fluorocarbons occurs, for example, in aerosol products, it causes odor and coloring of the liquid due to oxidized alcohol, or corrosion of the container due to hydrogen halide, which is a decomposition product, and in polyurethane foaming, the amine catalyst Inactivation causes undesirable problems such as a decrease in expansion ratio, an increase in the viscosity of the raw material polyol, and a yellowish brown color in the product. These problems become even more significant in the case of hydrogen-containing fluorocarbons.

[Means for Solving the Problems 1] In order to solve the above-mentioned problems, as a result of repeated studies on stabilizers for hydrogen-containing chlorofluorocarbons, the present inventors have developed a solution that uses a hydrocarbon having a nitro group and an epoxy compound in combination. The present inventors have discovered that a remarkable stabilizing effect can be achieved by this, and have completed the present invention.

Specifically, the present invention relates to a method for stabilizing hydrogen-containing chlorofluorocarbons against alcoholic hydroxyl groups, which is characterized by containing a hydrocarbon having a nitro group and an epoxy compound.

Hydrocarbons having a nitro group in the present invention include:
Examples include known or well-known compounds, usually nitromethane, nitroethane, l-nitropropane, 2-nitropropane, nitrobenzene, dinitrobenzenes (0-
dinitrobenzene, m-dinitrobenzene and p-dinitrobenzene), trinitrobenzene, and the like. Examples of epoxy compounds include well-known and well-known compounds, but usually ethylene oxide, 1,2-butylene oxide, propylene oxide, styrene oxide, cyclohexene oxide, glycidol, epichlorohydrin, phenyl glycidyl ether, and glycidyl methacrylate. , allyl glycidyl ether,
Monoepoxides such as methyl glycidyl ether, or dieboxides such as jepoxybutane and vinylcyclohexene dioxide are preferably selected.

Hydrogen-containing fluorocarbons in the present invention include tetrachloromonofluoroethane, trichlorodifluoroethane, dichlorotrifluoroethane, monochlorotetrafluoroethane, trichlorofluoroethane, dichlorodifluoroethane, chlorodifluoroethane, dichlorofluoroethane, chlorodifluoroethane, chlorofluoroethane, and the like. Can be mentioned. In addition, some of these fluorocarbons have isomers, but each isomer may be used alone or as a mixture of isomers. Furthermore, mixtures of hydrogen-containing fluorocarbons and hydrogen-free fluorocarbons may be used. It may also be a mixture of

In addition to the hydrogen-containing chlorofluorocarbons mentioned above, trifluoroethane, tetrafluoroethane, etc. containing only hydrogen and fluorine can also be stabilized by the present invention. Preferred hydrogen-containing fluorocarbons include blowing agents, propellants,
It can be suitably used as a solvent, has little effect on ozone layer destruction, and has a boiling point that is neither too low nor too high. From this point of view, ethane-based fluorocarbons are preferable to methane-based fluorocarbons, dichlorodifluoroethane is more preferable because it is easily available, and 1,1-dichloro-2,2,2-chlorofluorocarbons are particularly preferable because of its high stability.
Trifluoroethane is preferred.

Compounds containing alcoholic hydroxyl (□) that decompose fluorocarbons include monohydric or polyhydric alcohols such as methanol, ethanol, propatool, ethylene glycol, propylene glycol, and glycerin, and polyisocyanates. There are various polyols for producing polyurethane.Polyols include compounds having two or more OH groups such as glycols, alkanolamines, glycerin, and sugars, or active hydrogen compounds such as ethylenediamine. Polyether polyols are made by reacting atom-containing compounds with epoxides such as ethylene oxide, propylene oxide, epichlorohydrin, and butylene oxide, or polybasic acids such as adipic acid and phthalic acid are reacted with polybasic acids such as ethylene glycol, diethylene glycol, and propylene glycol. Examples include polyester polyols made by reacting alcohols with polyesters, etc. Also included are polyols for polyurethane obtained by other compounds and reaction methods.

The content ratio of the stabilizer in the present invention is not particularly limited, but in hydrocarbons having a nitro group, 0.001
~5.0 wt%, preferably 0.05-2. Owt%
is appropriate. Also, for epoxy compounds, 0.00
1-5. Owt%, preferably 0.01-2. Owt%
is appropriate. The stabilizer can be added in advance to the hydrogen-containing fluorocarbon or alcohol, or to a mixture of hydrogen-containing fluorocarbon and alcohol. It is also possible to mix and add the stabilizers of the present invention or to add other stabilizers.

[Examples] Hereinafter, the present invention will be specifically explained using Examples, but the present invention is not limited only to these Examples.

Examples and comparative examples are shown in the table. The following mixed liquid was prepared as a sample, and 4 parts by weight of pure water and 4 parts by weight of Freon 123 (CIC12CFs) were added.
0 parts by weight A predetermined amount of stabilizer is mixed with this, sealed in a pressure-resistant glass container, maintained at a temperature of 90°C in a hot air circulation thermostat, and subjected to a heating test for 3 days. Since hydrogen chloride is generated, the degree of decomposition can be determined by measuring the pH of the solution after the test, and the stabilizing effect can be measured by the degree of increase in chromaticity.

After the heating test, the chromaticity of the sample was determined according to JIS K-690.
Measure according to 1. That is, the chromaticity is expressed in Gardner by comparison with a standard solution. Additionally, 30 ml of isopropyl alcohol aqueous solution (volume ratio of isopropyl alcohol/pure water = 10/8) was added and mixed to 5 g of the sample solution, and the pH was adjusted.
Measure.

Note that the pH before the test was 11.5, and the chromaticity was Gardner 1 or less.

[Effect of the invention] Hydrogen-containing fluorocarbons stabilized according to the method of the invention have 1
Can be used as a blowing agent, aerosol or solvent, and is particularly effective in improving the storage stability of polyols containing hydrogen-containing fluorocarbons as a blowing agent.Usually, polyurethane foam is formed by reacting polyisocyanates and polyols. In many cases, hydrogen-containing fluorocarbons and polyols are mixed in advance and stored for a long time, in which case the stabilized hydrogen-containing fluorocarbons of the present invention can be used without adversely affecting polyurethane foam formation. Decomposition of hydrogen-containing fluorocarbons during storage can be suppressed.

Claims (1)

[Claims] (1) A method for stabilizing hydrogen-containing fluorocarbons against alcoholic hydroxyl groups, which comprises containing a hydrocarbon having a nitro group and an epoxy compound.