JPH01211539A - Stabilization of hydrogen-containing fluorocarbon - Google Patents

Abstract

PURPOSE:To improve the stability of a hydrogen-containing fluorocarbon against alcoholic hydroxyl group, by adding a combination of a compound such as styrene or vinyltoluene and acrylic acid or methacrylic acid to a hydrogen- containing fluorocarbon. CONSTITUTION:A lower aliphatic halogenated hydrocarbon containing fluorine, halogen other than fluorine and at least one hydrogen (i.e. hydrogen-containing fluorocarbon) is stabilized by adding preferably 0.01-5.0wt.% (based on the hydrogen-containing fluorocarbon) of a compound of formula (R<1>-R<4> are H or 1-3C hydrocarbon group) (e.g., alpha-methylstyrene or p-isopropenyltoluene) in combination with an acrylic acid ester or a methacrylic acid ester (preferably an ester containing at least one group selected from hydroxyl group, ether group and epoxy group). The fluorocarbon is especially effective in improving the storage stability of a polyol containing the hydrogen-containing fluorocarbon as a foaming agent.

Description

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

[Prior art and problems to be solved by the invention] 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. It is being 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.

Generally, Freon is often used in combination with an alcoholic hydroxyl group. For example, alcohol is added to a solvent to improve solubility, and to a propellant to dissolve a water-soluble active ingredient. 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] In order to solve the above-mentioned problems, as a result of repeated studies on stabilizers for hydrogen-containing fluorocarbons, the present inventors developed a compound represented by the following general formula (1) (hereinafter referred to as compound (1)) and acrylic esters or methacrylic esters, especially hydroxyl groups,
At least one selected from ether group and epoxy group
The present inventors have discovered that a remarkable stabilizing effect can be exerted by incorporating an acrylic ester or methacrylic ester containing a group of

(R1, R2, R3 and R4 are hydrogen or have 1 carbon atom
~3 hydrocarbon groups. ) That is, 1 the present invention contains the compound (1) and an acrylic ester or a methacrylic ester, particularly an acrylic ester or a methacrylic ester containing at least one group selected from a hydroxyl group, an ether group, and an epoxy group. The present invention relates to a method for stabilizing hydrogen-containing fluorocarbons against alcoholic hydroxyl groups.

Compound (1) in the present invention is exemplified by known or well-known compounds, but usually styrene, vinyltoluene, a-methylstyrene, p-isopropenyltoluene, p-isopropenyl-0-xylene, or p-isopropenyltoluene. Isopropenyl-a-ethylstyrene and the like are selected.

The alcohol component of the acrylic ester or methacrylic ester in the present invention preferably contains a hydroxyl group, an ether group, or an epoxy group in addition to the hydroxyl group that forms the ester with ffI. As these compounds.

Examples include known or well-known compounds, such as polyalkylene glycol (HO(RO)n!(,,F<:
alkylene group, n=1 to 9), a compound in which one of the hydroxyl groups of polyalkylene glycol is etherified (HO(R
O)nR', R': alkyl group) or alcohols having an epoxy group, such as glycidyl alcohol. In the case of a polyalkylene glycol having two hydroxyl groups, a diester may be formed with an acid, at least one of which is acrylic acid or methacrylic acid.

As the stabilizer of the present invention, monoesters of polyalkylene glycols are particularly preferred. i.e. 110 (RO)
nR', (R: alkylene group having 5 or less carbon atoms, R'
: Monoacrylic ester or monomethacrylic ester of hydrogen atom or alkyl group, n=1 to 9). For example, acrylates include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, diethylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, and the above methacrylates.

Acrylic esters or methacrylic esters in the present invention are considered to have a high stabilizing effect because they contain at least one hydroxyl group, ether group, or epoxy group, but acrylic esters or methacrylic esters that do not contain these groups Nisder methacrylate, such as an alkyl ester of acrylic acid or methacrylic acid, may also be used.

Hydrogen-containing chlorofluorocarbons in the present invention include tetrachloromonofluoroethane, trichlorodifluoroethane, dichlorotrifluoroethane, monochlorotetrafluoroethane, trichlorofluoroethane, dichlorodifluoroethane, chlorotrifluoroethane, dichlorofluoroethane, chlorodifluoroethane, and chlorofluoroethane. Examples include. Also, among these CFCs,
Although some compounds have isomers, each of the isomers may be used alone or as a mixture of isomers. Furthermore, a mixture of these hydrogen-containing fluorocarbons and a mixture of hydrogen-free fluorocarbons may be used.

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- is particularly preferred because of its high stability.
Trifluoroethane is preferred.

Compounds containing alcoholic hydroxyl groups that decompose CFCs include methanol, ethanol, propatool,
There are various polyols for producing polyurethane by reacting with monohydric or polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin, and polyisocyanates. Examples of polyols include compounds having two or more 011 groups such as glycols, alkanolamines, glycerin, and sugars, or compounds containing active hydrogen atoms such as ethylenediamine, ethylene oxide, propylene oxide, epichlorohydrin, Examples include polyether polyols made by reacting epoxides such as butylene oxide, and polyester polyols made by reacting polybasic acids such as adipic acid and phthalic acid with polyhydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol. It also includes other compounds and polyols for polyurethane obtained by reaction methods.

The content ratio of the former compound (1) or acrylic acid ester or methacrylic acid ester, which is a stabilizer in the present invention, is not particularly limited, but is 0.5% relative to hydrogen-containing chlorofluorocarbon.
0.001 wt% or more, preferably 0.001 wt% or more. Old~5. Owt% is appropriate. The stabilizer can be added in advance to the hydrogen-containing fluorocarbon or alcohol, or to a mixture of the hydrogen-containing fluorocarbon and alcohol. In addition, the stabilizer of the present invention is
It is also possible to use a mixture of two or more kinds, or to use other stabilizers in addition to the stabilizer of the present invention.

[Example J] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

Examples and comparative examples are shown in the table. Prepare the following mixture as a sample.

Polyol EL-750ED I 00 parts by weight (manufactured by Asahi Olin Co., Ltd.) Catalyst Dabco 331. V
2 parts by weight (manufactured by Sankyo Air Products) Foam regulating agent 311-193 2
Parts by weight (manufactured by Toshi Silicone Co., Ltd.) Pure water 4 Parts by weight Freon 123 (C1lClxCFs)
40 parts by weight of this was mixed with a predetermined amount of stabilizer, sealed in a pressure-resistant glass container, and heated to 90°C in a hot air circulation thermostat.
and conduct a heating test for 3 days. When CFC decomposes, hydrogen chloride is generated, so the pl+ of the liquid after the test
By measuring this, the degree of decomposition can be determined, 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 - 690I.
Measure according to. That is, the chromaticity is expressed in Gardner by comparison with a standard solution.

In addition, add isopropyl alcohol aqueous solution to 5 g of sample solution (volume ratio of isopropyl alcohol/pure water = 10/6).
Add 30ml, mix and measure the pH.

The pl+ before the test was 11.5, and the chromaticity was Gardner l.
It was F.

[Effect of the invention] Hydrogen-containing fluorocarbons stabilized according to the method of the present invention are
It 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. Normally, when polyurethane foam is formed by reacting polyisocyanates and polyols, hydrogen-containing fluorocarbons and polyols are often mixed in advance and stored for a long time. In this case, by using the stabilized hydrogen-containing fluorocarbon of the present invention, decomposition of the hydrogen-containing fluorocarbon during storage can be suppressed without adversely affecting polyurethane foam formation.

Claims (2)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R^1, R^2, R^3 and R^4 are hydrogen or hydrocarbon groups with 1 to 3 carbon atoms.) 1. A method for stabilizing hydrogen-containing fluorocarbons against alcoholic hydroxyl groups, the method comprising the step of containing a compound containing alcoholic acid and an acrylic ester or methacrylic ester. (2) The method for stabilizing hydrogen-containing fluorocarbons according to claim 1, wherein the acrylic ester or methacrylic ester contains at least one group selected from a hydroxyl group, an ether group, and an epoxy group.