JPS6340459B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an absorption refrigerant composition used in absorption refrigerant chillers and heat pumps applied to air conditioning. Structure of conventional examples and their problems In general, an absorption refrigeration cycle is a closed circuit that contains an absorption refrigerant composition inside.By evaporating the liquefied refrigerant in an evaporator that is part of the circuit, an absorption refrigeration cycle is Removes heat and freezes. The refrigerant vapor vaporized in the evaporator comes into contact with a low refrigerant concentration solution in the absorber and is absorbed. A high refrigerant concentration solution that has absorbed refrigerant is
By receiving heat from an external heat source, refrigerant vapor is released. The vaporized refrigerant vapor is then condensed in a condenser and sent as liquefied refrigerant to an evaporator. The solution that has released the refrigerant vapor returns to the absorber as a low refrigerant concentration solution and absorbs the refrigerant vapor again. The highest possible effectiveness for such cooling and heating can only be achieved at high temperatures of the refrigerant-rich solution in the generator. However, although absorption refrigerant compositions using monochlorodifluoromethane (R22) as a refrigerant and N,N-dimethylformamide (DMF) or tetraethylene glycol dimethyl ether (TEGDME) as an absorbent have been proposed, these has an insufficient lifespan for practical use. One of the reasons for this is that when these are heated, R22 decomposes and produces products such as hydrochloric acid and hydrofluoric acid, which corrode the metals that make up the equipment, and the absorbent also decomposes at the same time, causing damage to the equipment. This is because it caused a fatal problem of deterioration of the physicochemical properties of the composition and was completely unacceptable. Such deterioration and decomposition reactions are extremely individual and complex depending on the constituent components and combinations, and therefore thermal stabilization at high temperatures is extremely difficult.
Therefore, although R22/DMF and R22/TEGDME absorption refrigerant compositions have superior physicochemical properties compared to other compositions, they are still not practical due to the drawbacks mentioned above. It has not yet become a reality. Purpose of the Invention The purpose of the present invention is to provide a composition that is highly stable at high temperatures so that absorption refrigerators, heat pumps, etc. can achieve the best effects against decomposition and deterioration of such absorption refrigerant compositions. It is about providing. Structure of the Invention The absorption refrigerant composition related to the present invention includes methane-based,
Fluorinated hydrocarbons such as ethane, amide,
A phosphonate compound and a phosphate compound are added to an absorption refrigerant composition consisting of a polar organic solvent such as a glycol ether organic solvent. DESCRIPTION OF THE EMBODIMENTS In general, the absorption refrigerant composition must have good thermal stability and sufficient stability against the action of coexisting metals in order to obtain maximum effectiveness. To this end, it is partially accepted to use the known antioxidants and the phosphonate compounds described. However, although the thermal stability of the composition was improved by using additives, there were some cases where sulfur formation was observed, or copper plating phenomenon on dissimilar metals was observed, so the results were not satisfactory. I haven't gotten used to it. This is because, for example, when a copper plating phenomenon occurs, sliding resistance increases in the moving parts of the refrigerator, resulting in an increase in machine loss. Therefore, from a practical point of view, it is expected to develop an absorbing refrigerant composition that has excellent thermal stability and has a rust-preventing effect on coexisting metals. In view of these points, the present inventors conducted various studies and succeeded in developing an absorption refrigerant composition that meets the above expectations by adding a phosphonate compound and a phosphate compound in a binary manner. That is, the composition of the present invention suppresses the products accompanying the decomposition of the refrigerant by adding two components;
It has excellent characteristics such as being able to withstand stable use at high temperatures, and suppressing the plating phenomenon by suppressing the catalytic action of coexisting metal ions (for example, copper). Therefore, it can be said that the absorption refrigerant composition according to the present invention has improved thermal stability and is sufficiently stable against the effects of coexisting metals. Fluorinated hydrocarbons according to the present invention include monochlorodifluoromethane, dichloromonofluoromethane (R21), trifluoromethane, monochlorotetrafluoroethane (R124), monochlorotrifluoroethane (R133), monochlorodifluoroethane and mixtures thereof, Includes all fluorinated hydrocarbons selected as refrigerants depending on the operating conditions of the absorption cycle. In addition, polar organic solvents include formamide, acetamide, monomethylformamide, monomethylacetamide, tetramethylurea, N-methylpyrrolidone, N,N-dimethylformamide, N,N
-Amide compounds having an -CON- bond in the molecule, such as -dimethylacetamide, (DMA), N-dimethylpropionamide (DMP), N,N-diethylformamide, and mixtures thereof, as well as ethylene glycol dimethyl ether, ethylene glycol diethyl Ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether (DEGDME), diethylene glycol, diethylene ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether (T ₃ EGDME), triethylene glycol diethyl ether, triethylene glycol dibutyl ether, TEGDME , tetraethylene glycol diethyl ether, and tetraethylene glycol dibutyl ether.
(OC ₂ H ₄ )nOR [n=1-4, R: alkyl group]
The organic solvents include the glycol ether compounds shown in and mixtures thereof, and include organic solvents selected in combination with refrigerants other than those listed. The phosphonate compounds and phosphate compounds mentioned above have the chemical formula (R ₁ O) (R ₂ O)
Denoted by PR ₃ and (R ₄ O) (R ₅ O) (R ₆ O) PO,
In the formula, R ₁ to _{R 6} each independently represent a hydrogen group, an alkyl group,
They are an alkenyl group, a phenyl group, an alkylphenyl group, an alkylene phenyl group, and an alkylene alkylphenyl group. In addition, these compounds are called trimethylphosphonate or trimethylphosphonate when all of R ₁ to R ₆ are substituted with a relative of the substituent, such as an alkyl group such as methyl. be done. Therefore, the phosphonate compounds and phosphate compounds according to the present invention include methyl, ethyl,
Alkyl groups having 1 to 18 carbon atoms such as isopropyl, butyl, 2-ethylhexyl, isooctyl, isodecyl, dodecyldecyl, tridecyl, lauryl, octadecyl and oleyl, and alkyl groups having 1 to 9 carbon atoms such as nonylphenyl and cresyl. This includes those composed of substituents such as alkylphenyl groups having Since in this case phosphorus is considered to be the active group with respect to stabilization, the size of the constituents R ₁ to R ₃ is not critical, for example in the case of phosphonate compounds, but depends on boiling point, melting point, solubility in organic solvents and toxicity. As long as we take into account, all of R ₁ to _{R 3} are the same or different, and the same applies to phosphate compounds as well, including all tri- or g-substances in which two are the same and the rest are different. This compound also includes mono. A stabilizing effect can be obtained by dually adding these to the absorption refrigerant composition, and the addition amount is preferably in the phosphorus concentration range of 0.05 to 0.5% by weight, and a more significant stabilizing effect is achieved at a phosphorus concentration of 0.05 to 0.2% by weight. shows. The novel absorption refrigerant composition according to the invention is a significantly more stabilized composition compared to conventional compositions. Even at high temperatures of 200° C. or higher, deterioration and decomposition of fluorinated hydrocarbons and organic solvents is suppressed, yellowing of the composition is slow and minimal, and it does not solidify into a tar-like black color. Furthermore, from the viewpoint of the lifespan of the composition, it is stabilized approximately 10 to 20 times, and a long lifespan when used in equipment can be expected. [Example 1] Mix R124 and TEGDME at a ratio of 2:1, add the compounds shown in Table 1, coexist with copper and stainless steel (SUS-304), seal in a Pyrex tube, and heat-resistant at 220℃. I conducted a test.

[Example 2]

R124 and DMF were mixed at a ratio of 2:1, a phosphonate compound, a phosphate compound, copper and stainless steel were added, and a heat resistance test was conducted at 160°C. The results are shown in Table 2. As a result, the sample to which no phosphonate or phosphate compound was added turned black on the 10th day, and quantitative analysis of the amount of decomposed fluorine revealed that approximately 1 kg of R124 had been decomposed. In addition, at phosphorus concentrations such as samples where the amount of phosphonate and phosphate compounds added is 0.05% by weight or less, the amount of decomposed fluorine and the release of iron and copper ions are large, as seen in the change in the solution of the sample, and the addition effect is There was no such thing at all; in fact, the sample was worse. On the other hand, in the phosphorus concentration range of 0.05 to 0.2% by weight, as in samples , , , , etc., the color of the composition was yellowish and the effect was significant. Further sample,, etc. 0.2~0.5
At a phosphorus concentration of % by weight, the color of the composition is deep yellow or brown, and although there are some fluctuations in the decomposition of R124, an effective effect is obtained. However, the sample,
As in, when the phosphorus concentration exceeds 0.5% by weight,
There were considerable differences depending on the type of compound, and sometimes unfavorable effects appeared. Therefore, considering the influence of composition, price, etc.
At a phosphorus concentration of 1% by weight or more, the stabilizing effect found with the added amount cannot be expected. Preferably 0.05~
A sufficient stabilizing effect can be expected if it is added within a phosphorus concentration range of 0.5% by weight. Despite this, 0.05~
A phosphorus concentration of 0.2% by weight shows a significant stabilizing effect.

[Example 3]

Samples as shown in Table 3 were prepared in the same manner as in Example 1. Samples, 〓〓, 〓〓, 〓〓 are obtained by binary addition of phosphonate and phosphate compounds, and as comparative examples for each, samples 〓〓, 〓〓,
〓〓,. In addition to thermal stability as an evaluation method,
Added the effect of preventing copper plating. This method was carried out by measuring changes over time in the copper plating, in which copper ions are dissolved and liberated as the sample is heated, and adhere to the coexisting stainless steel and aluminum. As a result, although samples 〓〓, 〓〓, 〓〓, had excellent thermal stability, some of them had a fast copper plating speed on stainless steel, aluminum, etc., whereas samples 〓〓 , 〓〓, 〓〓 were excellent in both characteristics and showed a sufficient stabilizing effect. At the same time, quantitative analysis of A1, Fe, Cu, etc. was performed, and the increase in metal ions in the composition corresponded well with the quantitative analysis of free halogens and the qualitative and quantitative analysis of decomposition products by chromatography.

[Table] Effects of the Invention The present invention is a novel stabilized composition consisting of a fluorinated hydrocarbon, an organic solvent, and a phosphonate compound and a phosphate compound. Regardless of the situation, a sufficient stabilizing effect can be obtained.

Claims (1)

[Scope of Claims] 1. An absorption refrigerant composition consisting of a fluorinated hydrocarbon and a polar organic solvent has the chemical formula (R ₁ O) (R ₂ O) PR ₃
and (R ₄ O) (R ₅ O) (R ₆ O) PO. 2 The amount of the phosphonate compound and the phosphate compound added is such that the phosphorus concentration is 0.05.
The absorption refrigerant composition according to claim 1, characterized in that the content is 0.5 wt%.