JPH01265038A - Stabilization of bromine-containing fluorocarbon - Google Patents

Abstract

PURPOSE:To improve stability of bromine-containing fluorocarbon, useful as a blowing agent, aerosol, solvent, etc., to alcoholic hydroxyl group, by using an epoxy compound as a stabilizer. CONSTITUTION:In using (A) a bromine-containing fluorocarbon unstable to an alcoholic hydroxyl group, preferably dibromofluoromethane and (B) an alcoholic hydroxyl group-containing compound, the component A and the component B or a mixture thereof is blended with >=0.001wt.%, preferably 0.01-5.0wt.% based on the component A of an epoxy compound, preferably mono--diepoxide such as preferably 1,2-butylene oxide, propylene oxide, styrene oxide, diepoxybutane, etc. to suppress decomposition of the component A and to improve storage stability of polyol especially containing the component A as a blowing agent without exerting a bad influence on formation of polyurethane foam.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for stabilizing lower aliphatic halogenated hydrocarbons containing bromine and halogens other than bromine (hereinafter referred to as F1). It is something.

[Prior Art and Problems to be Solved by the Invention] It is known that bromine-containing fluorocarbons 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. Also, among halogens,
Bromine has an extremely low bonding energy with carbon compared to fluorine and chlorine, so bromine-molded fluorocarbons need to be more stable than conventional fluorocarbons that do not contain bromine.

Generally, Freon is often used in combination with an alcoholic hydroxyl group. For example, in a solvent, alcohol is added to increase the solubility [First, in a propellant, alcohol is added for the purpose of dissolving the 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 low foaming ratio, low viscosity of the raw material polyol, and yellowish browning of the product. These problems are even more severe in the case of bromine-containing chlorofluorocarbons.

[Means to Solve the Problem] In order to solve the above-mentioned problems, as a result of repeated studies on stabilizers for bromine millifluorocarbons, the present inventors found that an epoxy compound exhibits a powerful stabilizing effect. We have discovered that this can be done and have completed the present invention.

That is, the present invention relates to a method for stabilizing bromine-containing chlorofluorocarbons against alcoholic hydroxyl groups, which is characterized by containing an epoxy compound.

Examples of the epoxy compound in the present invention include known or well-known compounds, but usually ethylene oxide,
1.2-butylene oxide, propylene oxide,
Monoepoxides such as polyethylene oxide, cyclohexene oxide, glycidol, epichlorohydrin, phenylglycidyl ether, glycidyl methacrylate, allylglycidyl needle, methylglycidyl needle, or dieboxides such as jepoxybutane and vinylcyclohexene dioxide are preferably used. To be elected.

The bromine-containing chlorofluorocarbons used in the present invention include monobromotrichloromethane, dibro-dried dichloromethane, tribromomonochloromethane, monobromodichloromonofluoromethane, dibromomonochloromonofluoromethane, tripro-dried fluoromethane, monobromomonochlorodifluoromethane, and dibromomonochloromethane. Difluoromethane, monopromotrifluoromethane, monobromodichloromethane, dibromomonochloromethane, tribromomethane, monobromomonochloromonofluoromethane, dibromomonofluoromethane, monobromodifluoromethane, monobromomonochloromethane, dibromomethane, monobromomonofluoromethane , monobromomethane, dibromotetrafluoroethane, etc., and these can be used alone or as a mixture thereof.

A preferred bromine-containing fluorocarbon is a blowing agent.

It can be suitably used for propellants and solvent blades, and its boiling point is neither too low nor too high. From this point of view, dibromodifluoromethane is preferred.

When using the bromine-containing chlorofluorocarbon as a blowing agent in the present invention, water, methylene chloride, low-boiling hydrocarbons such as butane and hexane, inert gases such as air and nitrogen, trichlorofluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, etc. At least one kind selected from bromine-free fluorocarbons such as methane, tetrachlorodifluoroethane, trichlorotrifluoroethane, and dichlorotetrafluoroethane can be further used in combination.

Compounds containing alcoholic hydroxyl groups that decompose fluorocarbons include monohydric or polyhydric alcohols such as methanol, ethanol, propatool, ethylene glycol, propylene glycol, and glycerin, and polyisocyanates to form polyurethane. There are a variety of polyols for manufacturing. Examples of polyols include 2 or more 011 groups such as glycols, alkanolamines, glycerin, and sugars.
or polyether polyols made by reacting active hydrogen atom-containing compounds such as ethylene diamine with epoxides such as ethylene oxide, propylene oxide, epichlorohydrin, butylene oxide,
Alternatively, polybasic acids such as adipic acid and phthalic acid are reacted with polyhydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol, and polyester polyols are also available. It also includes other compounds and polyols for polyurethane obtained by reaction methods.

The content ratio of the epoxy compound in the present invention is not particularly limited, but is 0.001 wt% with respect to bromine-containing fluorocarbons.
Above, preferably 0. Old~5. Owt% is appropriate.

The epoxy compound can be added in advance to the bromine-containing fluorocarbon or alcohol, or to a mixture of bromine-containing fluorocarbon and alcohol. It is also possible to further add other stabilizers to the epoxy compound of the present invention.

For example, nitro compounds such as nitromethane and nitroethane, phenols such as 2,6-di-butyl-p-cresol and p-cresol, aromatic hydrocarbons such as α-methylstyrene, (meth)acrylic esters, etc. esters and phosphites such as dimethyl phosphite,
At least one type selected from Kasa can be used in combination.

[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. Prepare the following mixed solution as a sample, and add polyol EL-750ED I On weight 1□
1 part (manufactured by Asahi Olin Co., Ltd.) Catalyst Dabco 331J
2 Weight: 1" part (manufactured by Sankyo Air Protect Co., Ltd.) Foam stabilizer 511-193
2 Part for car (manufactured by Toshi Silicone Co., Ltd.) Pure water 4 Part by weight Bromine-containing Freon 12B, (CBr2F2) 4
A predetermined amount of a stabilizer is mixed with this, and the mixture is 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. When decomposition of fluorocarbon occurs, hydrogen chloride is generated, so the degree of decomposition can be determined by measuring the pl+ of the liquid after the test, and the stabilizing effect can be measured by the -Lyt degree of chromaticity.

After the heating test, the chromaticity of the sample is measured according to JIS K-69 old. That is, the chromaticity is expressed in Gardner by comparison with a standard solution. Further, 30 ml of an isopropyl alcohol aqueous solution (volume ratio of isopropyl alcohol/pure water = 10/6) is added to and mixed with 5 g of the sample liquid, and pu is measured.

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

[Effect of the invention] The bromine-containing fluorocarbon stabilized according to the method of the invention has the following properties:
It can be used as a blowing agent, aerosol or solvent, and is particularly effective in improving the storage stability of polyols containing bromine-containing fluorocarbons as a blowing agent. Normally, when polyurethane foam is formed by reacting polyisocyanates and polyols, the bromine-containing fluorocarbon and the polyol are often mixed in advance and stored for a long time. In this case, if the stabilized bromine-containing fluorocarbon of the present invention is used, decomposition of the bromine-containing fluorocarbon during storage can be suppressed without adversely affecting polyurethane foam formation.

Claims (1)

[Claims] (1) A method for stabilizing bromine-containing fluorocarbons against alcoholic hydroxyl groups, which comprises incorporating an epoxy compound.