JPH01265039A - 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 a phenol 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 0.0005-2.0wt.%, preferably 0.001-1.0wt.% based on the component A of a phenol which may contain any of substitutent groups such as alkyl group, alkenyl group, alkoxy group, carboxy group, carbonyl group or halogen besides hydroxyl groups 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 bromine-containing fluorocarbons). It is.

[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 and produce aldehydes and ketones. There is. Furthermore, among halogens, bromine has extremely low bonding energy with carbon compared to fluorine and chlorine, so bromine-containing fluorocarbons need to be more stable than conventional bromine-free fluorocarbons.

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, 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 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 bromine-containing chlorofluorocarbons.

[Means for Solving the Problems] In order to solve the problems mentioned above, the present inventors investigated stabilizers for chlorofluorocarbons containing good wood, and as a result, the present inventors discovered that phenols are
The present invention was completed by discovering that a sound stabilizing effect can be exhibited.

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

In the present invention, phenols include phenols containing various substituents other than hydroxyl groups, such as alkyl groups, alkenyl groups, alkoxy groups, carboxyl groups, carbonyl groups, and halogens. For example, 2.6-G-t-
Butyl-p-cresol, 0-cresol, m-cresol, p-cresol, thymol, p-t-butylphenol, 〇-methoxyphenol, m-methoxyphenol, p-methoxyphenol, eugenol, isoeugenol, butylhydroxyanisole, These include monovalent phenols such as phenol and xylenol, or divalent phenols such as 1-butylcatechol, 2,5-di-1-amylhydroquinone, and 2,5-di-1-butylhydroquinone.

In the present invention, the cross-containing fluorocarbons include monobromotrichloromethane, dibromodichloromethane, tribromomonochloromethane, monobromodichloromonofluoromethane, dibromomonochloromonofluoromethane, tribromomonofluoromethane, monobromomonochlorodifluoromethane, Dibromodifluoromethane, monopromotrifluoromethane, monobromodichloromethane, dibromomonochloromethane, tribromomethane, monobromomonochloromonofluoromethane, dibromomonofluoromethane, monobromodifluoromethane, monobromomonochloromethane, dibromomethane, monobromomonofluoromethane Examples include methane, monobromomethane, dibromomonofluoromethane, and these can be used alone or as a mixture.

Preferred bromine-containing chlorofluorocarbons are those which can be suitably used as blowing agents, propellants, solvents, etc., and whose boiling points are 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, low-boiling hydrocarbons such as methylene chloride-5-butane and hexane, inert gases such as air and nitrogen, trichlorofluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, etc. At least one member selected from bromine-free fluorocarbons such as methane, tetrachlorodifluoroethane, trichlorotrifluoroethane, and dichlorobuthrafluoroethane can be further used in combination.

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 glycols and alkanolamines! Polynylene, which is made by reacting a compound with two or more former groups such as n, glycerin, and sugars, or a TT compound containing an active hydrogen atom such as ethylenediamine, with an epoxide such as ethylene oxide, propylene oxide, epichlorohydrin, and butylene oxide. Examples include delpolyol, polybasic acids such as adipic acid and phthalic acid, and polyhydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol, and polyester polyols. It also includes other compounds and polyols for polyurethane obtained by reaction methods.

The content ratio of phenols in the present invention is not particularly limited, but is from 0,0005 to
2. Owt, %, preferably 0.001-1. Owt
% is appropriate v1. Phenols 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 phenols of the present invention.

For example, nitro compounds such as nitromethane and nitroethane, aromatic hydrocarbons such as a-methylstyrene, 1.2-
At least one selected from epoxy compounds such as butylene oxide and propylene oxide, esters such as (meth)acrylic acid ester, and phosphites such as dimethyl phosphite 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 mixture as a sample and add polyol El, -750ED too heavy.
, part (manufactured by Asahi Olin Co., Ltd.) Catalyst Dabco 331J
2 ITT Kawabe Sankyo (manufactured by Air Protect Co., Ltd.) Foam stabilizer Sl+-1932 weight: 11 parts (manufactured by Toshi Silicone Co., Ltd.) Pure water 4
Bromine-containing CFC 12132 (CBr2Fz)
40 parts by weight of this was mixed with a predetermined amount of stabilizer, and this was sealed in a pressure-resistant glass container and heated to a temperature of 9 in a hot air circulation thermostat.
The temperature is maintained at 0° C. and a heating test is conducted for 31 hours. When CFC decomposes, hydrogen chloride is generated, so the pH of the liquid after the test is
By measuring H, the degree of decomposition can be determined, and the stabilizing effect can be measured based on the chromaticity of 10″ft.

After the heating test, the chromaticity of the sample is measured according to JIS K-69 old. That is, the chromaticity is expressed in degrees Gardner by comparison with the standard i$ solution. In addition, add isopropyl alcohol aqueous solution (isopropyl alcohol/
Add and mix 30 ml of pure water (volume ratio = In/6), pl
+ is measured.

The pl+ before the test was 11.5, and the chromaticity was Gardner 1.
It was below.

[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, the decomposition of the bromine-containing fluorocarbon during storage can be suppressed without adversely affecting the formation of polyurethane foam.

Claims (1)

[Claims] (1) characterized by containing phenols;
A method for stabilizing bromine-containing chlorofluorocarbons against alcoholic hydroxyl groups.