JPH045708B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a fluorochlorohydrocarbon composition, and more particularly to a composition comprising a fluorochlorohydrocarbon, a boron compound, and a phosphite ester. The composition of the present invention is useful as a working fluid, a heat transfer medium, a blowing agent in the production of plastic foam, and the like. Conventional technology and its problems Fluorochlorohydrocarbons (hereinafter referred to as fluorocarbons)
is widely used as a refrigerant in refrigerators. In the refrigeration cycle of a refrigerator, the refrigerant reaches a high temperature in the compressor. Freon is a stable compound, so it does not decompose under normal refrigeration cycle conditions, but if the condensation temperature is high or the evaporation temperature is low, the temperature rise in the compressor will be large and it may decompose. Recently, power generation using Rankine cycle using Freon has been put into practical use, but in the above-mentioned refrigerators and Rankine cycle, Freon comes into contact with lubricating oil and metal. In addition, pipes are filled with fluorocarbons and heat is transferred using its sensible heat and its evaporation and condensation processes, but even in such heat transfer equipment, fluorocarbons and metals are comes into contact. Furthermore, metals may also coexist when Freon is used as a blowing agent in the production of plastic foams such as polyurethane, polystyrene, polyethylene, polypropylene, polyvinyl chloride, and ethylene-vinyl acetate copolymers. In such cases, fluorocarbons are easily decomposed by the action of metals, and the degree of decomposition of fluorocarbons when they come into contact with lubricants and metals is greater than when only fluorocarbons and lubricants come into contact. becomes. In the usage of fluorocarbons as described above, when the decomposition of fluorocarbons and lubricating oil progresses under high temperatures, the thermodynamic properties of the former deteriorate and the lubricating performance of the latter also decreases, so the ability of fluorocarbons and Rankine cycles is reduced. descend. When fluorocarbons decompose, halogens are generated and corrode metals, and hydrogen is generated along with this metal corrosion, which also deteriorates the heat exchange characteristics of heat engines such as refrigerators. This also applies to the heat transfer equipment described above. In order to cope with the recent improvement in the performance of devices and equipment using fluorocarbons and the resulting rise in temperatures at which fluorocarbons are used, various methods for preventing decomposition of fluorocarbons and methods for removing decomposition products have been proposed. For example, in order to prevent the decomposition of fluorocarbons, there are methods of adding furan to fluorocarbons (Japanese Patent Publication No. 40-22374), methods of adding nitrous oxide (Japanese Patent Application Laid-open No. 48-49685), and phosphorous acid esters. (Japanese Unexamined Patent Publication No. 55-48277),
A method of adding dialkylbenzoerythritol diphosphite (Japanese Unexamined Patent Publication No. 70082/1982) has been proposed, and a method of adsorbing and removing decomposition products with an absorbent is also known. However, none of these methods can be said to be sufficiently effective and have not yet been able to satisfy the advanced functions currently required. That is, these additives cannot prevent the decomposition of fluorocarbons to a satisfactory degree, or cannot be used in heat transfer equipment (eg, heat pipes), foaming agents for plastics, and the like. Means for Solving the Problems In view of the above-mentioned problems of conventional fluorocarbon compositions, the present inventor has conducted various studies to obtain a fluorocarbon composition with better stability and various performances, and has identified The inventors have discovered that when a boron compound and a phosphite ester are used in combination, the decomposition of fluorocarbons is extremely effectively suppressed, and the present invention has been completed. That is, the present invention provides the following fluorochlorohydrocarbon composition: "(a) consisting of a fluorochlorohydrocarbon, a boron compound, and a phosphite ester; (b) the boron compound is boric acid, (c) the phosphite is a dialkyl phosphorite (provided that the alkyl group has 1 to 11 carbon atoms); ,
at least one selected from the group consisting of diphenyl phosphite and dialkylpentaerythster diphosphite (however, the alkyl group is a lower alkyl group), and (d) the blending ratio of the boron compound and the phosphite ester is 5:95 to 95:5, and the total amount of both compounds is 0.01 to 5% by weight of the fluorochlorohydrocarbon. In the present invention, fluorochlorohydrocarbon refers to a saturated aliphatic hydrocarbon in which at least one hydrogen is replaced by fluorine and at least one hydrogen is replaced by chlorine, and the number of carbon atoms is 1 to 6. , more preferably 1 or 2. Preferred specific examples of fluorochlorohydrocarbons include chlorodifluoromethane, dichlorodifluoromethane,
Examples include trichlorofluoromethane, chloropentafluoroethane, dichlorotetrafluoroethane, and trichlorotrifluoroethane, but the fluorochlorohydrocarbon used in the present invention is not limited to these. In the present invention, the boron compound is at least one selected from the group consisting of boric acid, triphenyl esters and trialkyl esters of boric acid, and alkyl esters of diphenylborinic acid.
Use seeds. When used in the form of an alkyl ester, an alkyl group having 1 to 5 carbon atoms is preferred. In the case of trialkyl esters, the alkyl groups may be the same or different. Preferred specific examples of boron compounds are as follows. Boric acid type...boric acid, triphenylborate;
trialkylborates having groups such as methyl, ethyl, n-propyl, and isopropyl as alkyl groups; Diphenylborinic acid: monoalkyl diphenylborinates having groups such as methyl, ethyl, n-propyl, and isopropyl as alkyl groups. In the present invention, the phosphite ester is
Dialkyl phosphites (wherein the alkyl group has 1 to 11 carbon atoms), diphenyl phosphites and dialkylpentaerythritol diphosphites (where the alkyl group is a lower alkyl group) are used. In the case of dialkyl esters, the alkyl groups may be the same or different. Preferred specific examples of dialkyl esters of phosphorous acid are shown below. Dialkyl esters...dimethyl phosphite, diethyl phosphite, di-n-propyl phosphite, diisopropyl phosphite, dibutyl phosphite, dilauryl phosphite, etc. Dialkylpentaerythritol phosphite...dimethylpentaerythritol diphosphite, diethylpentaerythritol diphosphite, di-n-propylpentaerythritol diphosphite, diisopropylpentaerythritol diphosphite, dibutylpentaerythritol diphosphite, etc. In the present invention, the blending ratio of the boron compound and the phosphite ester is 100 parts by weight in total,
The former is 5 to 95 parts by weight, while the latter is 95 to 5 parts by weight. When the amount of boron compound is less than 5 parts by weight and
If it exceeds 95 parts by weight, the desired effect will not be fully achieved. In the composition of the present invention, the total amount of the boron compound and phosphite used is in the range of about 0.01 to about 5% based on the weight of Freon. If the amount is less than about 0.01% by weight, the desired effect will not be fully achieved, whereas if it exceeds about 5% by weight, no significant improvement in the effect will be observed. The boron compound and phosphite ester may be added to the fluorocarbon as they are, or may be added after being dissolved in a suitable solvent. Suitable solvents for this purpose include those that can dissolve boron compounds and phosphite esters, can also dissolve in fluorocarbons without reacting with them, and are stable against heat, such as dioxane, methyl acrylate, etc. , tertiary butanol and the like. Effects of the Invention According to the present invention, the following effects are achieved. (1) It is more stable at high temperatures than fluorocarbon compositions containing known stabilizers. For example, when trichlorofluoromethane (Freon-11) is used as a working fluid, its use limit temperature can be raised by about 40°C by adding a boron compound and a phosphite. (2) Compared to known fluorocarbon compositions, lubricants and/or
It is also difficult to decompose under conditions of contact with metals. (3) Compared to known fluorocarbon compositions, it is less corrosive to metal parts of equipment and equipment. (4) It also exhibits excellent performance as a blowing agent for producing plastic foams such as polyurethane, polystyrene, polyethylene, polypropylene, polyvinyl chloride, and ethylene-vinyl acetate copolymers. Examples The features of the present invention will be further clarified by the following Examples and Comparative Examples. Examples 1 to 8 and Comparative Examples 1 to 7 A composition consisting of 2 g of trichlorofluoromethane and the additives shown in Table 1 was placed in a heat-resistant glass tube (inner diameter 6
mm, outer diameter 10 mm, length 250 mm), add 0.02 g of lubricating oil (JIS turbine oil No. 1) and steel pieces (JIS
SS41, 2mm x 5mm x 50mm) and sealed, 130
After heating at °C for a predetermined time, the appearance of the composition was observed, and the chlorine compounds present in the composition and the chlorine compounds adhering to the steel pieces were measured using an ion chromatograph. The results are shown in Table 1. The appearance of the composition was evaluated based on the following criteria. A... No change B... Colored yellow C... Colored brown

[Table] As is clear from the results shown in Table 1, when a boron compound and a phosphite are used together,
The effect of suppressing the decomposition of chlorofluorocarbons is greater than when using known stabilizers. Example 9 and Comparative Examples 8 to 10 A heating test was conducted in the same manner as Comparative Examples 1, 2, and 6 and Example 1 except that the amounts of trichlorofluoromethane and lubricating oil were each 1 g. Table 2 shows the results after heating for 480 hours.

[Table] Example 10 and Comparative Examples 11-13 The amounts of trichlorofluoromethane and lubricating oil were each 1 g, and three types of metal pieces (Examples 1-5
Similar steel piece, 2mm x 5mm x 50mm Cu and 2mm
A heating test was conducted in the same manner as in Comparative Examples 1, 2, and 6 and Example 1, except that an Al piece measuring 5 mm x 50 mm was used. Table 3 shows the results after heating for a predetermined period of time.

【table】

Claims (1)

[Scope of Claims] 1 (a) consists of a fluorochlorohydrocarbon, a boron compound and a phosphite, (b) the boron compound is boric acid, triphenyl ester and trialkyl ester of boric acid, and alkyl ester of diphenylborinic acid (c) the phosphite is a dialkyl phosphorite (however, the alkyl group has 1 to 11 carbon atoms);
at least one selected from the group consisting of diphenyl phosphite and dialkyl pentaerythster diphosphite (however, the alkyl group is a lower alkyl group), and (d) the blending ratio of the boron compound and the phosphite ester is 5:95 to 95:5, and the total amount of both compounds is 0.01 to 5% by weight of the fluorochlorohydrocarbon.