JPS6340460B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an absorption refrigerant composition used in absorption refrigerators 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, absorption refrigerant compositions using monochlorodifluoromethane (R22) as a refrigerant and N,N-dimethylformamide (DMP) or tetraethylene glycol dimethyl ether (TEGDME) as an absorbent have been proposed, but 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 complicated depending on the constituent components and their combinations, so 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 phosphite 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 partly accepted to use known antioxidants and the phophite compounds described. However, although the thermal stability of the composition was improved by using additives, there were cases where sludge was formed or copper plating phenomenon occurred on dissimilar metals, so the results were not satisfactory. Not blooming. 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 mechanical 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 phosphite compound and a phosphate compound in a binary manner. That is, by adding two elements, the composition of the present invention can withstand stable use at high temperatures by suppressing products caused by decomposition of the refrigerant, and can suppress the catalytic action of coexisting metal ions (e.g., copper). It has excellent features such as suppressing the plating phenomenon by suppressing 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 with -CON- bonds in the molecule, such as -dimethylacetamide (DMA), N-dimethylpropionamide (DMP), N,N-diethylformamide, etc., 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, Chemical formula R such as tetraethylene glycol diethyl ether and tetraethylene glycol dibutyl ether
(OC ₂ H ₄ )nOR [n=1-4, R: alkyl group]
Organic solvents including the glycol ether compounds shown in and mixtures thereof and selected in combination with refrigerants other than those described above are included. The phosphite compounds and phosphate compounds mentioned above have the chemical formula (R ₁ O) (R ₂ O)
It is represented by (R ₃₀ )P and (R ₄ O) (R ₅ O) (R ₆ O) PO, and R ₁ to R ₆ in the formula are each independently a hydrogen group, an alkyl group, an alkenyl group, a phenyl group, They are an alkylphenyl group, an alkylphenyl group, an alkylenealkylphenyl group, an alkylenephenyl group, and an alkylenealkylphenyl group. In addition, these compounds are characterized by the structural form of phosphorus relative to oxygen and the type of substituent, for example, when all of R ₁ to _{R 6} are substituted with an alkyl group such as methyl, each is replaced with trimethyl phosphite or trimethyl phosphite. It is called Hate. Therefore, the phosphite compounds and phosphate compounds related to the present invention are:
Alkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, isopropyl, butyl, 2-ethylhexyl, isooctyl, isodecyl, dodecyldecyl, tridecyl, lauryl, octadecyl and oleyl, and 1 to 9 carbon atoms such as nonylphenyl and cresyl. It includes those composed of substituents such as alkylphenyl groups having an alkyl group. 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 phosphite compounds, but depends on the 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 all of the substances in trees or gs where two are the same and the rest are different are included,
The same applies to phosphate compounds, and this compound further 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 approximately 10 to 20 times more stable and can be expected to have a long lifespan when used in equipment. [Example 1] Mix R22 and DMA at a ratio of 1:1, add the compounds shown in Table 1, and mix copper, stainless steel (SUS-
304) and sealed in a Pyrex tube,
A heat resistance test was conducted at 160℃.

[Example 2]

R22 and DEGDME were mixed at a ratio of 2:1, a phosphite compound, a phosphate compound, copper and stainless steel were added, and a heat resistance test was conducted at 220°C. The results are shown in Table 2. As a result, the sample to which no phosphite or phosphate compound was added turned brown on the 60th day, and quantitative analysis of the amount of decomposed fluorine revealed that 6 mg of R22 had been decomposed. In addition, as seen in the change in the solution of the sample, at a phosphorus concentration where the amount of phosphite and phosphate compound added is 0.05% by weight or less, as in the sample,
There was a large amount of decomposed fluorine and a large amount of iron and copper ions were released, so there was no effect of the addition at all, and it was actually worse than the sample.
On the other hand, 0.05~0.2 like the sample etc.
In the weight percent phosphorus concentration range, the color of the composition was slightly yellowish and the effect was significant. Furthermore, at a phosphorus concentration of 0.2 to 0.5% by weight, as in the sample, the color of the composition was yellow, and although there were some fluctuations in the decomposition of R22, an effective effect was obtained. However, when the phosphorus concentration exceeded 0.5% by weight, as in the sample, considerable differences appeared depending on the type of compound, and sometimes undesirable 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 0.05-0.5
A sufficient stabilizing effect can be expected if the phosphorus concentration is added within the range of weight percent. Nevertheless, 0.05-0.2
Phosphorus concentrations of % by weight show a significant stabilizing effect.

[Example 3]

Samples as shown in Table 3 were prepared in the same manner as in Example 1. The sample 〓〓〓〓〓〓 was obtained by binary addition of phosphite and a phosphate compound, and as a comparative example for each, the sample 〓〓〓〓〓〓〓 was prepared by adding only the phosphite compound. In addition to thermal stability, the effectiveness of preventing copper plating was also evaluated as an evaluation method. 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.

[Table] As a result, although the samples 〓〓〓〓〓〓 had excellent thermal stability, some of them had a fast copper plating speed on stainless steel, aluminum, etc., whereas the samples 〓〓〓〓 〓〓〓 was excellent in both properties and showed a sufficient stabilizing effect. At the same time, quantitative analysis of Al, 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. Effects of the Invention A novel stabilized composition according to the present invention consisting of a fluorinated hydrocarbon, an organic solvent, and a phosphite compound and a phosphate compound, regardless of the type of metal and the mixing ratio of the fluorinated hydrocarbon and the organic solvent. , a sufficient stabilizing effect can be obtained.

Claims (1)

[Claims] 1. An absorption refrigerant composition comprising a fluorinated hydrocarbon and a polar organic solvent has the chemical formula (R ₁ O) (R ₂ O)
An absorption refrigerant composition characterized in that (R ₃ O) P, a phosphite compound represented by (R ₄ O) (R ₅ O) (R ₆ O) PO, and a phosphate compound are added dually. 2 The amount of the phosphite compound and the phosphate compound added is such that the phosphorus concentration is 0.05, respectively, with respect to the composition.
The absorption refrigerant composition according to claim 1, characterized in that the content is 0.5 wt%.