JPH0543493A - Method for suppressing decomposition of hydrogen-containing halogenated hydrocarbon - Google Patents

Abstract

PURPOSE:To obtain a method for suppressing decomposition of hydrogen- containing fluorocarbon during preservation of hydrogen-containing fluorocarbon, in a process using a hydrogen-containing fluorocarbon or during use of a product for a long period of time. CONSTITUTION:A hydrogen-containing fluorocarbon is blended with (1) at least one nitro compound and (2) at least one cyclic nitrogen compound or (1) at least one nitro compound, (2) at least one cyclic nitrogen compound and (3) at least one selected from a group consisting of an epoxy compound and an unsaturated alcohol compound to suppress decomposition of a hydrogen- containing fluorocarbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing the decomposition of hydrogen-containing halogenated hydrocarbons, and more specifically, by adding a mixture of a nitro compound and a cyclic nitrogen compound to hydrogen-containing halogenated hydrocarbons, The present invention relates to a method of suppressing the decomposition of contained halogenated hydrocarbons.

[0002]

2. Description of the Related Art Halogenated hydrocarbons (hereinafter referred to as CFCs) completely substituted with fluorine and chlorine are
It depletes the ozone layer, which has led to limited use and production. Therefore, the development of new CFCs that can replace these is highly desired, and as a typical example thereof, hydrogen-containing halogenated hydrocarbons (hereinafter referred to as hydrogen-containing CFCs) that have no or little risk of ozone layer depletion are regarded as promising. There is. However, hydrogen-containing CFCs are generally said to be less stable than conventional CFCs.

As a method for stabilizing hydrogen-containing CFCs, a method of adding a hydrocarbon containing a nitro group (Japanese Patent Laid-Open No. HEI-1)
No. 129944), a method of adding a hydrocarbon containing a nitro group and an epoxy compound (JP-A-1-12).
No. 8945) has been proposed.

The above-mentioned publications disclose methods for stabilizing hydrogen-containing CFCs, which are unstable when used in the coexistence state with a compound having an alcoholic hydroxyl group. For example, a solvent or a propeller is used. A method for stabilizing hydrogen-containing CFCs in the coexistence of alcohol added to the component, and a method for stabilizing hydrogen-containing CFCs in the presence of polyol in the urethane raw material in urethane foaming using hydrogen-containing CFCs as a foaming agent are described. Has been done. Since hydrogen-containing CFCs are generally unstable, they are easily decomposed in the presence of water or a metal, or by the action of light, heat, etc., except when used in the presence of a compound having an alcoholic hydroxyl group. Therefore, the hydrogen-containing fluorocarbon is gradually decomposed not only during its storage but also during the process and the product using the hydrogen-containing fluorocarbon. However, the above-mentioned known method does not describe the effect of suppressing the decomposition under such a condition that the hydrogen-containing CFC is decomposed, and in fact, there is a case where such a decomposition effect is small. Therefore, there is a strong demand for the development of a new decomposition suppression method capable of maintaining a stable state even under the various conditions described above.

The present inventor has conducted intensive studies in view of the above-mentioned state of the art, and as a result, has found that a mixture of a nitro compound and a cyclic nitrogen compound in a hydrogen-containing CFC or a mixture of the mixture with another compound. When compounded as a stabilizer, hydrogen is used for a long period of time under various conditions, that is, during storage, during use, and under any condition of the product, regardless of the presence or absence of the compound having an alcoholic hydroxyl group. It was found that the effect of suppressing the decomposition of the contained CFCs is achieved.

That is, the present invention provides the following method for suppressing decomposition of hydrogen-containing halogenated hydrocarbons: 1 Hydrogen-containing halogenated hydrocarbon containing at least one of (1) nitro compound and (2) cyclic A method for suppressing decomposition of a hydrogen-containing halogenated hydrocarbon, which comprises blending at least one nitrogen compound (hereinafter, this combination may be referred to as a first composition). 2 At least one kind of nitro compound (1), at least one kind of cyclic nitrogen compound (2), and at least one kind selected from the group consisting of (3) epoxy compound and unsaturated alcohol compound are added to the hydrogen-containing halogenated hydrocarbon. A method for suppressing decomposition of a hydrogen-containing halogenated hydrocarbon characterized by being blended (hereinafter, this combination may be referred to as a second composition). In this specification, "%" and "parts" mean "wt%" and "parts by weight", respectively.

The following are examples of hydrogen-containing halogenated hydrocarbons to which the present invention is applied. Hydrogen-containing chlorofluorohydrocarbon (HCFC) ... Dichloromonofluoromethane (HCFC-21; hereinafter simply referred to as "2
1 ”), monochlorodifluoromethane (22), dichlorotrifluoroethane (123), monochlorotetrafluoroethane (124), dichloromonofluoroethane (141), monochlorodifluoroethane (142). Hydrogen-containing fluorohydrocarbon (HFC): difluoromethane (32), trifluoromethane (23), difluoroethane (152), trifluoroethane (143), tetrafluoroethane (134), heptafluoropropane (227), hexafluoropropane (236). When isomers exist in the above-mentioned hydrogen-containing halogenated hydrocarbon, each isomer alone or as a mixture of isomers can be a subject of the present invention.

Examples of the (1) nitro compound used in the method of the present invention are as follows. A. Aromatic nitro compounds: nitrobenzene, nitrotoluene (o-, m-, p-), chloronitrobenzene (o-, m-, p
-), Nitrobenzyl alcohol (o-, m-), 4-chloro-3-nitrobenzotrifluoride, m-dinitrobenzene, 2,4-dinitrofluorobenzene, 2,4-dinitrochlorobenzene, p-nitrophenetol , 3-nitrostyrene, 1,2,3-trichloro-4-nitrobenzene, nitrophenol (o-, m-, p-), nitroanisole (o-, m-, p-), fluoronitrobenzene (m-, p-
), 2-chloro-6-nitrotoluene, p-nitrophenetol, dinitrotoluene (2,4-, 2,6-,
3,4-), 2,4-dinitroanisole, 2,4-dinitrophenol, o-nitrobenzyl alcohol, 4-
Nitrocatechol etc. B. Aliphatic nitro compounds: nitromethane, nitroethane, nitropropane (1-, 2-), etc. Each of these nitro compounds may be used alone or
A mixture of two or more species can be used. Among these nitro compounds, nitrobenzene, nitromethane, nitrostyrene and nitrocatechol are more preferable.

Examples of the (2) cyclic nitrogen compound used in the method of the present invention are as follows. Methylpyrrole (N-, 2-, 3-), vinylpyridine (2-, 4)
-), N-methylmorpholine, benzotriazole and the like. These cyclic nitrogen compounds may be used alone or in combination of two or more. Among these cyclic nitrogen compounds, N-methylpyrrole and 4
-Vinylpyridine is more preferred.

In the first composition, usually (1) the nitro compound is 0.05 per 100 parts of the hydrogen-containing halogenated hydrocarbon.
About 5 parts and (2) about 0.05 to 5 parts of cyclic nitrogen compound (however, the total of both components is about 0.1 to 5 parts). A more preferable ratio is (1) the nitro compound 0.1 to 0.1 to 100 parts of the hydrogen-containing halogenated hydrocarbon.
It is about 5 parts and (2) the cyclic nitrogen compound is about 0.1 to 0.5 part (however, the total of both components is about 0.2 to 1 part). If the proportions of (1) nitro compound and (2) cyclic nitrogen compound are too low, the desired effect is not achieved, whereas if they are too high, further substantial improvement of the effect is observed. Absent.

In the second composition, (1) at least one kind of nitro compound and (2) at least one kind of cyclic nitrogen compound are further selected from the group consisting of (3) epoxy compound and unsaturated alcohol compound. At least 1 type is used together. Specific examples of these combined compounds (3) are shown below. Epoxy compound: 1,2-butylene oxide, isobutylene oxide, propylene oxide, epichlorohydrin, styrene oxide, glycidol and the like. Among these epoxy compounds, 1,2-butylene oxide and epichlorohydrin are more preferable. Unsaturated alcohol: propargyl alcohol, 3-methyl-1-buten-3-ol, 2-methyl-3-butyne-
3-all etc. Among these unsaturated alcohols, propargyl alcohol is more preferable. These combined compounds can be used alone or in combination of two or more kinds.

In the second composition, usually (1) the nitro compound is 0.05 per 100 parts of the hydrogen-containing halogenated hydrocarbon.
To about 5 parts, (2) about 0.05 to 5 parts of cyclic nitrogen compound and about 0.05 to 5 parts of combined compound (3) (however, 3
The total of the components is about 0.15 to 5 parts). A more preferable ratio is about 0.1 to 0.5 parts of (1) nitro compound with respect to 100 parts of hydrogen-containing halogenated hydrocarbon,
(2) The cyclic nitrogen compound is about 0.1 to 0.5 part and the combined compound (3) is about 0.1 to 1 part (however, the total of the three components is about 0.3 to 1 part). If the blending ratio of any one of these three components is too low, the desired effect is not achieved, while if it is too high, no substantial improvement in the effect is observed.

The stabilizer component comprising the above-mentioned (1) nitro compound and (2) cyclic nitrogen compound, or (1) nitro compound, (2) cyclic nitrogen compound and combined compound (3) is a target hydrogen-containing compound. Depending on the purpose of use, use of fluorocarbons, other substances mixed with fluorocarbons, temperature conditions during storage, production, and product use, the timing for blending fluorocarbons, the blending means, etc. can be arbitrarily selected.

[0014]

EFFECTS OF THE INVENTION According to the method of the present invention, the stability of the hydrogen-containing CFC can be remarkably enhanced during storage, use, and production of the CFC. Further, the method of the present invention, even under conditions used in the coexistence state with a compound having an alcoholic hydroxyl group,
It is possible to suppress decomposition of hydrogen-containing CFCs. Therefore, the present invention is extremely useful in practice as a method for suppressing the decomposition of hydrogen-containing CFCs used as a foaming agent, a refrigerant, a cleaning agent, a propellant, a fire extinguishing agent, a solvent, a dry etching agent, etc.

[0015]

EXAMPLES Examples and comparative examples will be shown below to further clarify the characteristics of the present invention.

Example 1 The components were mixed in the proportions shown in Table 1 below to prepare a mixed solution for producing a rigid polyurethane. Table 1 Polyol 100 parts Catalyst 2 parts Foam stabilizer 2 parts Pure water 2 parts Foaming agent (CFC or CFC containing hydrogen) 40 parts Note: Polyol ... Trademark "RX-500", Sanyo Chemical Co., Ltd. Catalyst ... Trademark " U-CAT1000 ", manufactured by San Abbott Co., Ltd. Foam stabilizer ... Trademark" SH-193 ", manufactured by Toray Silicone Co., Ltd.

A predetermined amount of the stabilizer was mixed with the obtained mixed liquid, which was then sealed in a pressure vessel made of iron and kept at 60 ° C. in a constant temperature bath to carry out a heating test for one month. In heating test,
When the hydrogen-containing CFC or CFC is decomposed, a specific decomposed gas is generated. Therefore, the concentration thereof was measured by a gas chromatograph, and the hydrogen-containing CFC or CFC decomposition inhibitory ability during storage was judged.

Further, 102 parts of crude polyisocyanate (trademark "MR-100", manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts of the mixed solution obtained above, and urethane foam was produced by hand mixing, and then 1 day. Aged
Then, the urethane foam after aging for one day was cut into a 10 cm square and vacuum packed with an aluminum laminate pack. Next, the vacuum-packed urethane foam was crushed with a press, and the concentration of the decomposition gas generated by the exothermic reaction was measured by gas chromatography to determine the ability to suppress decomposition of hydrogen-containing CFCs or CFCs during the foam formation reaction.

Further, the urethane foam vacuum-packed in the same manner as above was kept at 90 ° C. in a constant temperature bath, and the decomposition gas concentration after heating for 2 weeks was measured by a gas chromatograph to measure hydrogen-containing CFCs or CFCs during aging. The ability to suppress the degradation of was determined.

Further, a storage test was conducted on the assumption of use as a refrigerant. That is, hydrogen-containing CFCs 123 were placed in a 100 ml pressure-resistant glass container containing iron, copper and aluminum test pieces (5 mm x 50 mm x 2 mm each) at the same time.
And paraffinic mineral oil mixture (80/20; weight ratio)
Put 100 g, Comparative Examples 5-8 and 3B of Table 3A
Add a predetermined amount of the stabilizer shown in Examples 1 to 9 in the table and
After heating for 2 weeks, the ability to suppress decomposition was judged.

Tables 2-A to 2-C show the kinds of foaming agents, the kinds of stabilizers, and the amount (parts) of the stabilizer added to 100 parts of the foaming agent. In addition, Tables 3-A to 3
-Table C shows the decomposition gas generation concentration (based on the blowing agent) at each test stage. Table 2-A Comparative example HCFC or HFC stabilizing agent Addition amount 1 11 None-2 11 Nitrobenzene 1.0 3 11 Nitromethane 1.0 4 11 4-Vinylpyridine 1.0 5 123 None-6123 Nitrobenzene 1. 0 7 123 Nitromethane 1.0 8 123 4-Vinylpyridine 1.0 9 11 Nitrobenzene 0.5 4-Vinylpyridine 0.5 10 11 Nitromethane 0.5 Benzotriazole 0.5 11 11 4-Nitrocatechol 0.5 N -Methylpyrrole 0.5

Table 2-B Example Examples Foaming agent stabilizing agent Addition amount 1 123 Nitrobenzene 0.2 4-Vinylpyridine 0.3 2 123 Nitromethane 0.2 Benzotriazole 0.3 3 123 4-Nitrocatechol 0. 2 N-methylpyrrole 0.3 4 123 nitrobenzene 0.1 4-vinylpyridine 0.3 propargyl alcohol 0.3 5 123 nitromethane 0.2 benzotriazole 0.3 3-methyl-1-buten-3-ol 0 .3 6 123 3-nitrostyrene 0.1 N-methylpyrrole 0.3 1,2-butylene oxide 0.5 7 123 m-nitrotoluene 0.1 N-methylmorpholine 0.3 epichlorohydrin 0.5

Table 2-C Example Examples Foaming agent stabilizing agent Addition amount 8 141b Nitrobenzene 0.2 4-Vinylpyridine 0.3 9 141b Nitromethane 0.2 Benzotriazole 0.3 10 141b 4-Nitrocatechol 0. 2 N-methylpyrrole 0.3 11 141b nitrobenzene 0.1 4-vinylpyridine 0.3 propargyl alcohol 0.3 12 141b nitromethane 0.2 benzotriazole 0.3 3-methyl-1-buten-3-ol 0 .3 13 141b 3-nitrostyrene 0.1 N-methylpyrrole 0.3 1,2-butylene oxide 0.5 14 141b m-nitrotoluene 0.1 N-methylmorpholine 0.3 epichlorohydrin 0.5

Table 3-A Decomposition gas production concentration (ppm) Comparative example During storage During reaction During aging During storage 1 20000 350 6400-2 2300 120 5800-3 5800 380 8500-4 3000 3000 220 6200-5 3600 470 4100 1100 6 170 70 1300 450 7 500 500 250 2900 250 8 250 250 180 1800 550 9 2200 120 5600-10 4900 400 8300-11 2500 2500 220 6200-Note: Comparative Examples 1 to 4 and 9 to 11 (using CFC-11).
Then, dichloromonofluoromethane (HCFC-21)
There has occurred. In Comparative Examples 5 to 8 (using HCFC-123), 1-chloro-2,2,2-trifluoroethane (HCFC-13
3a) occurred.

[0025] The 3-B Table decomposition gas generated Concentration (ppm) Example savings built during storage during aging in reaction 1 120 0 520 370 2 160 20 780 80 3 120 0 600 170 4 100 0 380 340 5 120 20 450 50 6 80 0 300 120 7 100 0 380 150 Note: In Examples 1 to 7 (using HCFC-123), 1-
Chloro-2,2,2-trifluoroethane (HCFC-
133a) occurred.

[0026] The 3-C Table decomposition gas generated Concentration (ppm) Example savings built in reactions during aging of 8 180 0 800 9 320 0 980 10 190 0 760 11 140 0 320 12 180 0 550 13 80 0 380 14 1200 340 Note: In Examples 8-14 (using HCFC-141b),
Mainly 1-chloro-1-fluoroethylene was generated.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Ide 1-1 Nishiichitsuya, Settsu-shi, Osaka Daikin Industries, Ltd. Yodogawa Manufacturing Co., Ltd. (72) Tatsumi Tsuchiya Nishiichitsuya 1-1, Settsu-shi, Osaka Daikin Industries Yodogawa Manufacturing Co., Ltd. (72) Inventor Katsuji Fujiwara 1-1 Nishiichitsuya, Settsu-shi, Osaka Daikin Industry Co., Ltd. Yodogawa Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A method for suppressing decomposition of a hydrogen-containing halogenated hydrocarbon, which comprises blending (1) at least one nitro compound and (2) at least one cyclic nitrogen compound into the hydrogen-containing halogenated hydrocarbon. . 2. The hydrogen-containing halogenated hydrocarbon is selected from the group consisting of (1) at least one nitro compound, (2) at least one cyclic nitrogen compound, (3) epoxy compound and unsaturated alcohol compound. A method for suppressing decomposition of hydrogen-containing halogenated hydrocarbon, comprising blending at least one kind.