JPS5861172A - Absorption refrigerant composition - Google Patents

Abstract

PURPOSE:To prepare an absorption refrigerant composition having excellent thermal stability at high temperature, and suitable for an absorption refrigerating machine, heat pump, etc., by adding a phosphonate compound to a mixture of a fluorohydrocarbon as a solvent and an amide-type organic solvent as an absorbent. CONSTITUTION:The objective composition is prepared by adding (A) a phosphonate compound[preferably an alkyl phosphonate of formula (R1-R3 are H, alkyl, phenyl, or alkylphenyl)]to (B) a fluorohydrocarbon (preferably dichloromonofluoromethane, monochlorotetrafluoroethane, etc.) as a solvent and (C) an amide-type organic solvent (preferably N,N-dimethyl-formamide, N,N-dimethylacetamide, etc.) as an absorbent. The amount of the component (A) is 0.05- 0.5wt% of the component (C) in terms of phosphorus concentration. EFFECT:There is little yellowing of the composition and no formation of tarry black solid even at a high temperature, and the life of the composition is longer than that of the conventional one by a factor of 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel absorption refrigerant composition with excellent thermal stability for use in absorption refrigerators, heat pumps, and the like.

For example, an absorption refrigeration cycle is a closed circuit that contains an absorption refrigerant composition, and an evaporator that is part of the circuit evaporates the liquefied refrigerant to remove heat from the outside and perform freezing. The refrigerant vapor vaporized in the evaporator comes into contact with a low refrigerant concentration solution in the absorber and is absorbed. The high refrigerant concentration solution that has absorbed the refrigerant receives heat from an external heat source, resulting in refrigerant vapor? j, release. 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.

For such cooling and heating, the highest possible effectiveness can only be achieved at high temperatures of the refrigerant-rich solution in the generator.

However, conventionally, monochlorodifluoroenone (
R22), N,N-dimethylformamide (D
Absorption refrigerant compositions using MF) have been proposed;
Absorption refrigerators and heat pumps using these compositions have not yet been put into practical use. One of the causes of this is that when the above composition is heated to a high temperature of about 120°C or higher, R2
2 decomposes, producing products such as hydrochloric acid and hydrofluoric acid, which corrode the metals that make up the equipment, and DMF also decomposes at the same time, damaging the equipment. This was because they could not tolerate the fatal problem of deterioration. R22Fi.

It is relatively stable among fluorinated hydrocarbons, and it is well known that DMF produces decomposition products such as amines when coexisting with metals, but when used as an absorption refrigerant composition, each Degradation and decomposition reactions occur at a rate that is faster and more complex than expected from the thermal stability of the compound. 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, R22/DMF
Despite the fact that absorbent refrigerant compositions have superior physicochemical properties compared to other compositions, they have not yet been put into practical use due to the drawbacks mentioned above.

The object of the present invention is to provide a composition that is highly stable at high temperatures and can sufficiently achieve the best effect in absorption refrigerators, heat pumps, etc. against decomposition and deterioration of such absorption refrigerant compositions. be.

The present invention relates to monochlorodifuno-olomethane (R21),
Dichloromonofluoromethane (R22), trifluoromethane (R23), monochlorotetrafluoroethane (
, R124), monochlorotrifluoro[J ethane (R1
33), monochlorodifluoroenone (R142) and mixtures thereof, etc., and fluorinated hydrocarbons as refrigerants, N,N-7'methylformamide (DMF), N,N-methylacetic acid, etc. ]・Amide (DMA), N,N-dimethylpropionamide (
DMP), N,N-diethyl,],)Lmamide (DE
F) and mixtures thereof! , 1. A stable compound consisting of an amide organic solvent as an absorbent of choice, and a phosphonate compound of choice for alkylphosphonates, allylargylphosphomono-1, allylphosphomonate, and mixtures thereof1. 11-6S7I/(or "J:l, L" absorption refrigerant composition).

The fluorinated hydrocarbons listed in 11 Re hi are not limited to methane, ethane-based fluoride, and hydrogen. At least 11l-i1 or more J-0 hydrogen, at least 1
It contains a fluorinated hydrocarbon having more than one fluorine and one or more chlorine. Of course, it is also possible to use a 4-mer compound or a mixture. The choice is made depending on the operating conditions of the absorption cycle in this case, J:H, but particularly preferred is R21, as shown in the examples.
, R22, R23°R124, R133, R142. Particularly preferred are R22 and R124. Each of these fluorinated hydrocarbons is believed to exhibit excellent hydrogen bonding between one hydrogen within the molecule and the absorbent. Such hydrogen bonds increase the absorptive and dissolving power of the refrigerant. In addition, these fluorinated hydrocarbons have excellent equipment adaptability in terms of other physical and chemical properties.

Further, the amide organic solvent described above is DMF.

It is not limited to DMA, DMP and DEF, but includes those having at least one 2000N bond. Therefore, it is clear that formamide, acetamide, monomethylformamide, monomethylacetamide, tetramethylurea, N-methylpyrrolidone, and the like are included. Of course, a mixture of these may also be used. However, more preferred ones are DMF, DMA, DMP and D
There is EF engineering. Particularly preferred are DMF and DMA. and 7L et al.'s amide yarns are easy to form hydrogen bonds with the refrigerant and have a large ability to absorb and dissolve the refrigerant.

In addition, the phosphonate compound C mentioned above can be expressed by the chemical formula (R
IO) (R20) R5 (0) f+, denoted by P, J in philtrum
*R2 and R5 each independently represent a hydrogen group, an argyl group,
These include an alkenyl group, a phenyl group, an alkyltuunyl group, an alkenyl phenyl group, an alkylene argylphenyl group, an alkylene phenyl group, and an alkylene argylphenyl group. In this case, since the phosphonate is considered to be the active group with respect to stabilization, the constituents R,
R2 and R5,) are not critical to 11Fs. boiling point.

1.i! I! /,',1 *Considering solubility and toxicity in amide-based solvents (as long as 7, R,,
R2 and R3, 5-'' are the same or different, two are the same and the rest are different, or they can be used singly or 7' (- may be used in the plural. However, more than 1 -ma(2〈 is, as shown in the example, G2
-Ethylheginyl phospho-nit, dilauryl phosphonate.

Nododecylphosphonate. ditridecylphosphonate,
R, such as dodenrutridecylphosphonate-1, oleylphosphonate, di-n-butylhexylphosphonate, ethylphenylphosphonate, dimethylphenylphosphonate, and two alkyl groups in which R2 has 4 to 18 carbon atoms. and alkylphosphonates where R3 is a hydrogen group or an alkyl group, and R1 such as diphenylphosphonate, dinonylphenylphosphonate, phenylnonylphenylphosphonate, diphenylphosphonate, etc.
° Allylphosphonate, di-n-butylphenylphosphonate, dihexylphenylphosphonate, in which R2 has two alkylphenyl groups having a phenyl group or an alkyl group having 1 to 9 carbon atoms, and R5 is a hydrogen group;
R, , R such as dinonylphenylhexylphosphonate
Although it is an allyl alkylphosphonate in which 12 has at least one alkyl group, phenyl group, or alkylphenyl group, and R5 is a hydrogen group, it is not susceptible to thermal decomposition itself, and has a concentration of 1 unit per unit. Alkylphosphonates with wider tolerances are also preferred.

The absorption refrigerant composition of the present invention consisting of a fluorinated hydrocarbon, an amide organic solvent and a phosphonate compound (Ii are not particularly critical to each other. The amounts of refrigerant and absorbent are determined by the purpose of the equipment, as is well known. The phosphor concentration is mainly determined by the operating conditions used.The phosphone-1 compound should also be determined to such an extent that the thermodynamic and physicochemical properties of these compositions are not impaired.Thus, the phosphorus concentration should be 1% by weight. The above will have a negative effect on the IJe compound, not only will it not be possible to achieve an effect commensurate with the amount added, but will also increase the price.At a phosphorus a content of 0.5% to 1%, the phosphonate There are considerable differences depending on the molecular weight and structure of the compounds;
Some aralkyl phosphonates may even have negative effects. Therefore, a phosphorus concentration range of 0.05 to 0.6% by weight is preferable, and although a sufficient stabilizing effect can be expected in these ranges,
．． At a concentration of 2% by weight v1 shows a significant stabilizing effect.

The novel absorption refrigerant composition according to the present invention is a composition that is significantly more stabilized than conventional compositions. Even at high temperatures of 20°C or higher, the deterioration and decomposition of fluorinated hydrocarbons and amide-based organic solvents is suppressed, and the composition is slow and minimal in appearance, and does not solidify into a tar-like black color. Furthermore, from the viewpoint of the lifespan of the composition, it is approximately three times more stable, and a long lifespan can be expected when used in equipment.

As described above, the present invention was able to overcome the deterioration and decomposition reaction unique to hydrocarbon and amide organic solvents by adding an appropriate amount of a phosphonate compound, and was able to provide a novel stabilized absorption refrigerant composition. .

[Example 1] R22 and DMF were mixed at a ratio of 1:1, and the following compounds were added to DMF by 15% by weight, and aluminum, copper, and stainless steel (SUS-304) were added to the coexistence of a Vilex tube. It was sealed and a heat resistance test was conducted at 140°C.

■Dodecyltridecylphosphonate 1■ 2,6. -Di-t-butyl-P-creso■ Triethylenetetramine■ 2-Nitropropane [Co., Ltd.] Di-cyclohexylamine nitrite■ β-
Naphthol ■ Hexamethyltetraamine The numbers from ■ to ■ are each sample number, and the same applies to the following examples. (2) is a compound mainly used in extreme pressure additives, (2) to (2) are well known as antioxidants, (2) to (2) are rust preventives, and (2) to (4) are well known as DMF stabilizers. -! In addition, a sample consisting only of conventional R22 and DMF was designated as ■.

As a result, sample ■ already turned brown on the 1st day and turned into a tar-like black solution by the 3rd day, and samples ■ to ■ showed similar discoloration compared to sample ■, and the deterioration was 11 times faster. On the third day, all of the samples had turned black, whereas sample (2) had only a brown color. on the other hand,
The aluminum of samples ■ to ■ was severely corroded in a porous shape and covered with a tar-like substance, and the copper and stainless steel were also completely blackened, but in sample ■, only the aluminum was blackened, and the copper and stainless steel There was no abnormality.

Thus, it has been found that such absorption refrigerant compositions exhibit no effect of well-known antioxidants, rust inhibitors and DMF stabilizers, and that only dodecyltridecylphosphonate produces a significant stabilizing effect.

[Example 2] R124 and DMA were mixed at a ratio of 1:2, 1.0% by weight of the compound shown below was added to the DMA, copper and stainless steel were made to coexist, and the mixture was filled into a Pyrex tube and heated to 160
A heat resistance test was conducted at ℃.

■ Dilaurylphosphonate O Dilaurylphosphonate 0 Di-n-butylphenylphosphonate 0 Phenyl-α-naphthylamine@2,2.4-)dimethyl-1,2-enehydroquinoline o 2.4-Dinitrotoluene O Metaphenylenediamine Om-nidro'niline o-o LIi antioxidant and o-O are known as dehalogenation inhibitors. Also, R124 and DMA
A sample consisting only of

As a result, sample O exhibited a yellow color at the second week, and became completely black at 8 weeks [1], and the copper and stainless steel were also blackened. Compared to sample O, samples O-O turned black at the same level or acceleration (1: L 7', T. On the other hand, samples There were no abnormalities, and the solution was colorless or only slightly yellowed.

Therefore, anti-oxidant and )-rogen desorption prevention methods were not only ineffective at all, but also had a negative effect.

This means that although each of the compositions of Jl et al. shows a stabilizing effect when used alone, when the composition is combined with 7L/ζ, the deterioration and decomposition reaction is different from that of bt. J(
This is probably because it is configured. In other words, since the constituent components and combinations are extremely individual and complex, it can be said that it is difficult to find a stabilizer that is effective for them. On the other hand, among the antioxidants, phosphonate compounds showed remarkable effects as in Example 1, and at this time,
All of the alkyl phosphonates, allyl phosphonates and allyl alkyl phosphonates were excellent.

[Example 3] R124 and DMA were mixed at a ratio of 1:3, a phosphonate compound, copper and stainless steel were added, and the mixture was heated at 200°C.
A heat resistance test was conducted for 7 days. The type and amount of the phosphonate compound are shown in Table 1.

As a result, sample O to which phosphone-1 was not added turned black on the 7th day, and quantitative analysis of free...logen revealed that approximately 16% of R124 had been decomposed.

Also, samples 0, 0, such as o, o, o, o, o, etc.
At a phosphorus concentration of 5% by weight or less, there was no addition or effect at all, and it was actually worse than Sample O.

-10,000, sample e-43,0-0,0~[phase] and O~@
In the phosphorus concentration range of 0.05 to 0.2 double digit %, the composition was slightly colored or yellowish, and the decomposition of R124 was 1% or less.

Further samples O2O~0 and O75: how 0.2
At a phosphorus concentration of ~0.5 wt:1:%, the color of the composition was yellow or brown, and the decomposition of R124 was around 10%, although there was some variation. However, when the phosphorus concentration exceeds O, S weight %, as in sample 0.0°0, there are considerable differences depending on the type of phosphonate compound, and sometimes unfavorable effects occur.

Therefore, when considering the influence of the composition and the price, a stabilizing effect commensurate with the amount added cannot be expected with a phosphorus concentration of 1% by weight or more. A sufficient stabilizing effect can be expected if the phosphorus concentration is preferably 0.05 to 0.5% by weight.

Nevertheless, a phosphorus concentration of 2% by weight at 0.05 Fe-Q showed a significant stabilizing effect.

Table 1] Example 4 R124 and DMA were demixed in a ratio of 1=2, a phosphonate compound, copper and stainless steel were added, and a heat resistance test was conducted.

The results are shown in Table 2. The numbers in Table 2 indicate the number of days from the start of the test until the composition turns yellow, and these color changes correspond to deterioration of the composition and are in good agreement with the relative lifespan of the composition. This is well known to the researchers concerned.

Therefore, the larger the number, the better the thermal stability, increasing the stability of the composition.

Table 2 shows that a sufficient stabilizing effect can be obtained in all temperature ranges, but at temperatures above 200°C
1. Approximately 3 times better than sample O~0 without adding any compound,
It is stable for very long periods at temperatures below that temperature.

11 Example 6] In the same manner as in Example 1, samples as shown in Table 3 were prepared.
~0 was created. In addition, samples not containing a phosphonate compound were designated as 0 to ■ corresponding to samples O-O containing the phosphonate-1 compound, and the ratios were determined from Table 3.

As a result, compared to samples 0 to 0, samples O-O according to the present invention exhibited slower or less coloring of the composition, indicating a sufficient stabilizing effect.

At the same time, quantitative analysis of Mu-12-Fe, Cu, etc. was conducted, and the increase in metal ions in the composition corresponded well with the quantitative analysis of free halogen and the qualitative and quantitative analysis of decomposition products by chromatography.

Therefore, the novel composition according to the present invention consisting of a fluorinated hydrocarbon, an amide organic solvent, and a phosphonate compound can be used regardless of the type of metal and the mixing ratio of the fluorinated hydrocarbon and the amide organic solvent. It showed a sufficient stabilizing effect.

Claims (5)

[Claims] (1) An absorption refrigerant composition comprising a fluorinated hydrocarbon, an amide organic solvent, and a phosphonate compound. (2) The fluorinated hydrocarbon is monochlorodifluoromethane. The absorption refrigerant composition according to claim 1, comprising dichloromonofluoromethane, trifluoromethane, monochlorotetrafluoroethane, monochlorotrifluoroethane, monochlorofluoroethane, or a mixture thereof. (3) The amide organic solvent is N,N-trimethylformamide, N,N-dimethylacetamide, or N. 3. The absorption refrigerant composition according to claim 1 or 2, comprising N-dimethylglobionamide, N,N-diethylformamide and mixtures thereof. (4) A patent in which the phosphonate compound is represented by the chemical formula % (0), in which R4+ R2 and R3 are each independently a hydrogen group, an alkyl group, a phenyl group, or an alkylphenyl group, and mixtures thereof. Claim 1. The absorption refrigerant composition according to item 2 or 3. (5) The absorption refrigerant composition according to any one of claims 1 to 4, which comprises a phosphonate compound based on an amide organic solvent in a phosphorus concentration of 0.06 to 0.5% by weight.