JPH0124771B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for stabilizing lower aliphatic halogenated hydrocarbons containing fluorine and halogens other than fluorine. Lower aliphatic halogenated hydrocarbons containing fluorine and halogens other than fluorine (hereinafter referred to as front)
is known to easily react with alcoholic hydroxyl groups and decompose. Lower aliphatic halogenated hydrocarbons containing only fluorine are stable against alcoholic hydroxyl groups, but other fluorocarbons decompose through the following reaction to produce aldehydes and ketones. CCl ₃ F + CH ₃ OH → CHCl ₂ F + HCHO + HCl. Generally, Freon is often used in combination with an alcoholic hydroxyl group. For example, alcohol is added to a solvent to increase 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 opportunities for fluorocarbons to come into contact 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, and in polyurethane foaming, it causes inertness of amine-based contact. This decreases the foaming ratio and causes undesirable problems such as increased viscosity of the raw material polyol and yellowish brown color of the product.
For this reason, various stabilizers for fluorocarbons have been developed. For example, Japanese Patent Publication No. 39-23099 discloses α-methylstyrene, Japanese Patent Publication No. 47-625 discloses p-isopropenyltoluene, and Japanese Patent Publication No. 53-82708 discloses α-methylstyrene.
The publication proposes a combination of vinyltoluene and t-butylcatechol. According to studies conducted by the present inventors, it has been found that these conventional stabilizers do not necessarily have a sufficient stabilizing effect under severe conditions or for long-term stabilization. As a result of various studies on stabilizers with more stabilizing effects than conventional ones, the present inventors found that the general formula

Containing a hydrocarbon compound (hereinafter referred to as compound A) represented by the formula (R ₁ , R ₂ and R ₃ are hydrogen or a hydrocarbon group having 1 to 3 carbon atoms), a phenol, and an epoxy compound. It was discovered that CFCs can be stabilized even more than conventional stabilizers. That is, the present invention relates to a method for stabilizing chlorofluorocarbons against alcoholic hydroxyl groups using a stabilizer system consisting of the compound A, phenols, and epoxy compounds. Compound A in the present invention may be exemplified by known or well-known compounds, but usually α-methylstyrene, P-isopropenyltoluene, P-isopropenyl-o-xylene, P-isopropyl-α-ethylstyrene, or Vinyltoluene and the like are preferably selected. Furthermore, as the phenols, phenols containing various substituents such as an alkyl group, an alkenyl group, an alkoxy group, a carboxyl group, a carbonyl group, and a halogen in addition to a hydroxyl group are also effective. For example, 2.6-di-t-butyl-P-cresol, o,m,p-cresol, thymol, pt-butylphenol, O,m,p-methoxyphenol, eugenol, isoeugenol, butylhydroxyanisole, phenol, Monovalent phenol such as xylenol or t-butylcatechol, 2,
5-di-t-amylhydroquinone, 2.5-di-
These include divalent phenols such as t-butylhydroquinone. Further, as the epoxy compound, 1,2-butylene oxide, propylene oxide, styrene oxide, phenyl glycidyl ether, glycidyl methacrylate, allyl glycidyl ether, methyl glycidyl ether, etc. are suitably selected. In the present invention, fluorocarbons refer to lower aliphatic halogenated hydrocarbons having 1 to 4 carbon atoms and containing fluorine and halogens other than fluorine, particularly fluorocarbons having 1 to 2 carbon atoms.
It is a lower aliphatic halogenated hydrocarbon. Halogens other than fluorine include chlorine and bromine. Specific fronts include trichlorofluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, trichlorotrifluoroethane, tetrachlorodifluoroethane, dichlorotetrafluoroethane, monochlorotetrafluoroethane, bromochlorodifluoromethane, bromotrifluoromethane, etc. be. Among them, fluorocarbons with the same or smaller number of fluorine atoms as chlorine and/or bromine, such as trichlorofluoromethane, dichlorodifluoromethane, trichlorotrifluoroethane, and tetrachlorodifluoroethane, are particularly easy to decompose and are The invention achieves these high stabilities. Compounds containing alcoholic hydroxyl groups that decompose CFCs include methanol, ethanol,
There are various polyols for producing polyurethane by reacting with monohydric or polyhydric alcohols such as propanol, ethylene glycol, propylene glycol, and glycerin, and polyisocyanates. Examples of polyols include:
Ethylene oxide, compounds with two or more OH groups such as glycols, alkanolamines, glycerin, and sugars, or compounds containing active hydrogen atoms such as ethylenediamine.
Polyester polyols are produced by reacting polyether polyols with epoxides such as propylene oxide, epichlorohydrin, and butylene oxide, or by reacting polybasic acids such as adipic acid and phthalic acid with polyhydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol. be. It also includes polyurethane polyols obtained by other compounds and reaction methods. The amount of stabilizer added in the present invention is not particularly limited, but in compound A,
0.001 to 6.0%, preferably 0.05 to 2.0%, 0.0005 to 1% for phenols, preferably 0.001
~0.5%, 0.001-5.0 for epoxy compounds
%, preferably 0.05-1.0%. The stabilizer of the present invention can be added in advance to fluorocarbons or alcohol, or to a mixture of fluorocarbons and alcohol. It is also possible to add further stabilizers to the stabilizer system of the present invention. The fluorocarbons stabilized according to the method of the present invention are effective, for example, on the storage stability of polyols containing fluorocarbons as blowing agents. Normally, when polyurethane foam is formed by reacting polyisocyanates and polyols, the fluorocarbons and polyols are often mixed in advance and stored for a long time. In this case, if the stabilized fluorocarbon of the present invention is used, decomposition of the fluorocarbon during storage can be suppressed without adversely affecting polyurethane foam formation. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited only to these Examples. Examples 1-30 and Comparative Examples 1-32. Prepare the following mixture as a sample: N,N,N',N'-tetrakis-2-hydroxypropylethylenediamine 100 parts by weight triethylenediamine (DABCO33LV)
2 〃 Water 4 〃 Freon 11 (CCl ₃ F) 40 〃 Mix this with a specified amount of stabilizer, put it in a pressure-resistant glass container, maintain the temperature at 90℃ in an air bath, and conduct a heating test for 72 hours. Do this. When fluorocarbon decomposes, hydrogen chloride is generated, so the degree of decomposition can be determined by examining the pH, and the stabilizing effect can be measured by the degree of increase in chromaticity. After the above heating test, the chromaticity of the sample liquid was determined according to JIS K-
Measure according to 6901. That is, the chromaticity is expressed in Gardner by comparison with a standard solution. Also, add 30 ml of isopropyl alcohol aqueous solution (volume ratio of isopropyl alcohol/pure water = 10/6) to 5 g of sample solution.
Add, mix, and measure the PH. In addition, the pH before the heating test was 11.4, and the chromaticity was Gardner 1 or less (APHA 10).

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[Table] Reference example Sample mixture containing stabilizer used in Example 1 above
After stirring 146g and 262g of crude MDI (methylene diisocyanate) at a liquid temperature of 20°C for 5 seconds, they were placed in a wooden box (20cm x 20cm x 20cm), and the reactivity (gel time) was measured and found to be 30 seconds. Example 1
The gel time was measured in the same manner as described above, except that 146 g of the stabilizer-containing sample mixture used in Comparative Example 33 was used instead of the stabilizer-containing sample mixture used in Comparative Example 33, and the gel time was 41 seconds.

Claims (1)

[Claims] 1 General formula [Formula] (R ₁ , R ₂ and R ₃ are hydrogen or a hydrocarbon group having 1 to 3 carbon atoms)
1. A method for stabilizing fluorocarbons against alcoholic hydroxyl groups, the method comprising containing a hydrocarbon compound represented by the following, a phenol, and an epoxy compound.