JPH0239556B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for an absorption refrigerator comprising a refrigerant and an absorbent. Conventionally, the most widely used composition for absorption refrigerators is a water or methanol lithium halide based composition. Water and methanol have the advantage of having a large latent heat of vaporization and a large coefficient of performance (COP). However, when lithium halides are used as absorbents, the compositions are generally highly viscous, corrosive to metals, and prone to crystallization. In addition, the condenser and absorber must be cooled by water. Aqueous ammonia systems are also used, but although ammonia has the advantage of having a latent heat of vaporization greater than that of methanol, it has the disadvantage of high pressure during operation, and the toxicity of ammonia has hindered the spread of absorption refrigerators. It's summery. Halogenated methane-dimethylformamide systems have also been used, but their coefficient of performance (COP) is low. Furthermore, the halogenated methane-tetraethylene glycol dimethyl ether system requires high pressure during operation. In addition, halogenated methane-furan derivative systems (US Pat. Nos. 4,072,027 and 4,172,043) are also known. However, none of the known compositions for absorption refrigerators containing these compositions has been found to be satisfactory in terms of performance. Under these circumstances, the present invention provides a novel composition for absorption refrigerators that has many advantages as described below. That is, according to the present invention, at least one fluorinated alcohol refrigerant having 2 to 10 carbon atoms, which is liquid at room temperature and can become a vapor under normal pressure or reduced pressure when heated, and There is provided a composition for an absorption refrigerator comprising at least one type of absorbent having a normal pressure boiling point and capable of absorbing the refrigerant. Examples of the fluorinated alcohol in the composition of the present invention include fluorinated primary, secondary, and tertiary alcohols represented by the following general formulas (), (), and (). That is, the following formula (), () or (): (In the formula, the group R ¹ —CH ₂ —,

[Formula] and

[In the formula, R ⁷ and n are the same as defined in formula (); R ⁸ is an alkyl group having 1 to 4 carbon atoms]

There is a polyethylene glycol dialkyl ether represented by Specific examples include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dipropyl ether, and tetraethylene glycol dipropyl ether. Examples of the cyclic ethers include furan derivatives such as those described in US Pat. No. 4,072,027 (tetrahydrofurfuryl alcohol, ethyltetrahydrofurfuryl ether, etc.). Examples of polyols include glycols and polyols.
_Examples include _C2-3 alkylene glycols and polyols having a valence of 3 or more. That is, examples of glycols include _C2-6 alkylene glycols, such as ethylene glycol and propylene _glycol . Poly
_Examples of _C2-3 alkylene glycols include diethylene glycol, triethylene glycol _, and the like represented by the formula (): H( _OCH2CH2 )nOH () (wherein n is an integer of 2 to 5). Examples of trivalent or higher polyols include glycerin, trimethylolpropane, hexanetriol, etc., and _C2-3 alkylene oxide adducts of these (for example, the number _of moles added is 1 to 12 moles). Esters include carboxylic acid esters, phosphoric acid esters, and boric acid esters. Examples of the carboxylic acid component in the carboxylic acid ester include the following. That is, there are aliphatic, alicyclic or aromatic mono- or polycarboxylic acids having C ₁ to ₃ (excluding the carbon atoms of the carboxyl group), specifically acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, These include adipic acid, tetrahydrophthalic acid, and phthalic acid. Also
Examples include C ₁ to ₈ (excluding carbon atoms of carboxyl group) oxycarboxylic acids, specifically glycolic acid, lactic acid, citric acid, tartaric acid, and the like. Hydroxy group-containing compounds constituting these carboxylic acids and esters include C ₁ to ₆ aliphatic, alicyclic, or aromatic alcohols, specifically methanol, ethanol, propanol, butanol, amyl alcohol, cyclohexanol, and benzyl. Alcohol, etc.; or the above-mentioned glycol monoalkyl ethers or the above-mentioned polyols. Specific examples of esters of these carboxylic acids and hydroxy compounds include lower alcohol esters of dicarboxylic acids such as dimethyl malonate and dimethyl oxalate; monocarboxylic acid esters such as amyl acetate and butyl propionate; ethylene glycol monomethyl ether acetate, and ethylene glycol monomethyl ether acetate. glycol monoethyl ether acetate,
Mention may be made of esters of glycol monoalkyl ethers of monocarboxylic acids such as diethylene glycol monoethyl acetate. In addition to these, there are cyclic esters such as _{the C3-6} lactone butyrolactone. Examples of phosphoric acid esters include esters of the above-mentioned hydroxy group-containing compounds or phenols and phosphorus-containing acids such as phosphoric acid and polyphosphoric acid, such as triethyl phosphate, tributyl phosphate, triphenyl phosphate, and tricresyl phosphate; Examples include phosphoric acid or polyphosphoric acid ethylene oxide adducts (additional moles are, for example, 3 to 12 moles). Examples of boric acid esters include boric acid esters of the above-mentioned hydroxy group-containing compounds, such as boric triesters, specifically glycol ether triborates. Amides include the formula (): (In the formula, R ⁹ , R ¹⁰ V and R ¹¹ are carbon atoms or C ₁ to ₁₀
Amide compounds represented by (alkyl group, phenyl group), such as dimethylformamide, dimethylacetamide, diethylformamide, formamide, acetamide, acetanilide, etc.; Cyclic amides, such as lactams with C ₃ or more, preferably C ₄ to ₁₂ , specifically pyrrolidone , caprolactam, caprilactam, laurolactam, etc.; these lactams
C _{1-4 alkyl} substituent, specifically N-methyl-
Examples include 2 _- pyrrolidone, N-ethyl-2-pyrrolidone, etc.; and _C2-3 alkylene adducts of the above lactams (number of moles added, 1 to 10 moles). Examples of amines include aliphatic monoamines of C ₆ or more, preferably C ₇ to ₁₅ , such as primary amines such as heptylamine, secondary amines such as dihexylamine, and tertiary amines such as trioctylamine;
Aliphatic polyamines such as alkylene diamine, specifically trimethylene diamine, hexamethylene diamine, etc.; polyalkylene polyamines, such as triethylenetetramine of polyethylene polyamine with a degree of polymerization of 2 to 6; cyclohexylamine, dicyclohexylamine, isophorone diamine , alicyclic amines such as dicyclohexylmethanediamine; aromatic amines such as benzylamine, dibenzylamine, xylene diamine, etc.; morpholines, aminothiazoles, imidazoles, piperidines, pyrazoles, pyrazolines, piperazines, pyrrolidine Heterocyclic amines such as indoles, quinolines, etc.;
and hydroxyalkyl-substituted products or _C2-3 alkylene oxide adducts of these amines ₍ number of moles added from 1 to 10), such as diethylaminoethanol, morpholine monoethylene oxide, etc.; and alkanolamines, such as mono-, di-, or tri-ethanolamine. , propanolamine, butanolamine or diethylaminoethanol. Imides include _C4-10 dicarboxylic acid imides such _{as maleic} acid and succinimide, as well as N- _C1-4 alkyl substituted products, amino ( _{C2-6 alkyl} ) substituted products, and _{C2-4 alkyl} substituted products of these imides. Examples include hydroxyalkyl substituted products. Examples of ketones include cyclohexanone, isophorone acetylacetone, and acetonitrile acetone; examples of aldehydes include C ₆ to ₁₂ aldehydes, such as heptaldehyde; and examples of nitriles include C ₅ to ₁₂ nitriles, such as valeronitrile. Can be mentioned. The above absorbents are listed in descending order of absorption capacity for the refrigerant 2,2,2-trifluoro-ethanol: amides (including cyclic amides);
The order is phosphoric acid esters, ethers and polyols, alkanolamines, ketones, boric acid esters, carboxylic acid esters, aldehydes, and amines. On the other hand, the order of thermal stability is ethers, polyols, cyclic amides, alkanolamines, and carboxylic acid esters. In view of these properties, suitable absorbents for use in this invention are ethers, especially glycol ethers and cyclic amides. Preferred among the glycol ethers are polyethylene glycol monoalkyl ethers represented by the formula (). Also preferred among the cyclic amides is N-alkyl-2-pyrrolidone, particularly N-methyl-2-pyrrolidone. In the inventive combination, the fluorinated alcohol and absorbent contents of the refrigerant are not particularly critical and can vary within a wide range. That is, based on the weight of the composition, the refrigerant fluorinated alcohol typically contains 5
Compositions are used that contain up to 60% by weight, preferably 10 to 50% by weight, and usually 40 to 95% by weight, preferably 50 to 90% by weight of absorbent. The above absorbents (especially ethers and polyols)
When using this, adding an organic amine to it will have a corrosion inhibiting effect on metals (iron).
In particular, when an organic amine with a boiling point of 150° C. or less is used, the amine is mixed into the fluorinated alcohol evaporated from the generator, and the corrosion inhibition effect is obtained on the metals in the equipment from the generator to the evaporator. Furthermore, the addition of this amine relaxes the deaeration conditions, and it is possible to improve the drawback that under insufficient deaeration conditions, the vapor pressure changes significantly and it is difficult to operate as a refrigerator. The organic amine used in combination is preferably one having a boiling point of 150°C or less, particularly 50 to 130°C. Such amines include amines (having a boiling point 50°C or more higher than the boiling point of the refrigerant) used as the absorbent.
Among them, those with a boiling point of 150°C or less and amines with a lower boiling point than that are included. _{Examples of suitable amines include aliphatic amines such as C1-6 aliphatic} primary amines (methylamine, ethylamine,
Alkylamines such as propylamine, butylamine, amylamine, and alkoxyalkylamines such as 3 _- methoxypropylamine and 3-ethoxypropylamine); _C2-7 aliphatic secondary amines (dimethylamine, diethylamine, dipropylamine, etc.); _{C3-7 aliphatic} tertiary amines (trimethylamine, triethylamine, etc.); cycloaliphatic amines such as cyclohexylamine; and heterocyclic amines such as morpholine. The amount of these organic amines used varies depending on their boiling point, but is usually 0.05 to 10% by weight, preferably 0.1 to 5% by weight, based on the weight of the absorbent. In the case of low boiling point amines (e.g. boiling point below 100°C), a small amount (e.g. 0.05-1
% by weight), but those with high boiling points (e.g. boiling point
(100 to 150°C), it is preferable to use a relatively large amount (for example, 1 to 5% by weight). When using an amine as an absorbent, it can be used in a larger amount (5 to 100% by weight) than the above. Water can also be added to the compositions of the invention. The addition of water is effective in preventing corrosion on carbon steel, and the amount added is 0.08% based on the weight of the composition.
It is preferably about 0.5% by weight. The compositions of this invention optionally have thermal stability,
In order to improve corrosion prevention properties, additives such as stabilizers and corrosion inhibitors can be included. Such additives include antioxidants such as benzotriazole, mercaptobenzotriazole, hindered phenols (such as 2,6-di-t-butylphenol); phosphites (U.S. Pat. Nos. 4,072,027 and 3,459,660); Copper oxide (as described in US Pat. No. 2,582,306). The amount of these additives is usually less than 5% by weight based on the weight of the composition, preferably
It is 0.01 to 2% by weight. In addition, from another perspective, the present invention provides an absorption refrigeration system using a volatile refrigerant and an absorbent, which has 2 to 10 carbon atoms, is liquid at room temperature, and becomes vapor at normal pressure or reduced pressure when heated. The present invention provides an absorption refrigeration system that uses at least one type of refrigerant that is a water-soluble fluorinated alcohol and at least one type of absorbent that has a higher normal pressure boiling point than the refrigerant and is capable of absorbing the refrigerant. A conventional absorption refrigerator can be used when refrigerating the composition of the present invention. Absorption refrigerators generally have a basic circuit configuration as shown in Figure 1, where 1 is an absorption liquid that absorbs a refrigerant and is diluted (a composition produced when an absorbent absorbs a refrigerant).
2 is a generator for heating and separating refrigerant from the generator 1;
A condenser (3) cools the gaseous refrigerant flowing in from the condenser 2 into a liquid refrigerant, and (3) reduces the pressure of the liquid refrigerant in the condenser 2 with a pressure reducer 4 and vaporizes it by dispersing it under low pressure conditions to achieve the desired cooling function. 5 is an absorber that enables continuous cooling movement in the evaporator 3 by absorbing the refrigerant vaporized in the evaporator 3 with an absorption liquid; 6 is an absorber in which the refrigerant is separated and absorbed in the generator 1; a heat exchanger that exchanges heat between the absorbent liquid (concentrated liquid) with a high absorbent concentration sent to the absorber 5 and the absorbent liquid (dilute liquid) with a low absorbent concentration returned from the absorber 5 to the generator (1); 7 is an absorption liquid circulation pump, and 8 and 9 are an analyzer and a rectifier, respectively, which separate the refrigerant and the absorbent when the refrigerant and the absorbent are azeotroped. The refrigeration cycle in an absorption refrigerator that uses fluorinated alcohol as a refrigerant, as described above, involves the generation of refrigerant vapor from a dilute liquid (absorbent liquid with low absorbent concentration), condensation and liquefaction of the refrigerant vapor, depressurization, and evaporation (vaporization) of the liquefied refrigerant. ), absorption of refrigerant vapor into a concentrated liquid (absorbing liquid with high absorbent concentration), etc. is achieved by repeating the process. The concentrations of the concentrated and dilute liquids mentioned above depend on the type of absorbent used and also on the operating conditions, i.e. the heating temperature of the dilute liquid (temperature of the generator), the evaporation temperature of the refrigerant liquid (temperature in the evaporator). , is arbitrarily set according to the absorption temperature of the refrigerant (temperature inside the absorber). The use of the composition for an absorption refrigerator of the present invention as described above has the following advantages, as will be explained in detail in Examples below. (1) The composition does not azeotrope, and the absorbent
Since a material with a normal pressure boiling point higher than 50°C is used, an analyzer and a rectifier are not required in the absorption refrigerator. (2) Since it can be operated at low pressure, there is no risk of leakage of liquid or gas from inside the machine, and it is possible to reduce the strength of the equipment and simplify maintenance management. (3) High vapor pressure drop rate. (4) The low viscosity of the composition reduces circulation power. (5) Since the composition does not have crystallization properties, circulating power is reduced and heat transfer resistance is reduced. It can also be used in cold regions. (6) The composition has low corrosivity to iron. (7) The composition is non-toxic. Also, as a fluorinated alcohol, it has a boiling point of 120℃.
When the following fluorinated alcohols are used, the following advantages are also obtained in addition to the above-mentioned advantages. (1) The temperature at which the refrigerant is separated from the composition is not very high. (2) Since the temperature at which the refrigerant is condensed is not very low (40° to 60°C), air cooling is sufficient for cooling the condenser and absorber. (3) A high coefficient of performance (COP) can be obtained. Therefore, when such a fluorinated alcohol is used as a refrigerant, the refrigerant can be separated from the absorption liquid even if the heating temperature in the generator (1) is not very high.
Even if the cooling temperature in the condenser 2 is not very low, the refrigerant can be condensed and liquefied. For example, if the heating temperature required in the generator (1) is 80
If the refrigerant is separated from the absorption liquid at ~200°C, especially at 80~120°C, it becomes possible to drive the generator relatively easily using solar heat as the heat source. Since the refrigerant can be liquefied at a condensing temperature of 40 to 60℃, even an air-cooled condenser can function well as a condenser.
Since it is absorbed in the absorber at a temperature of ~60°C, an air-cooled cooler in the absorber is sufficient. While satisfying these conditions, the refrigerant can have a vaporization temperature of 5 to 10°C, has a large latent heat of vaporization, and is less toxic, so the range of use of air-cooled absorption refrigerators can be significantly increased. The absorption refrigerating assembly of the present invention can be applied to both air-cooled and water-cooled systems, and refrigeration systems using this assembly can be used in various applications such as air conditioning and air conditioning equipment for homes, buildings, factories, etc. Next, the present invention will be explained by examples, but the present invention is not limited thereto. Example 1 The concentration of 2,2,2-trifluoro-1-ethanol (hereinafter referred to as TFE) was 30% by weight, and the organic compounds of various absorbents shown in Table 1 below were 70% by weight.
The reflux boiling point of TFE in the composition was measured and Table 1
It was shown to. As is clear from Table 1, compounds such as amine, alkanolamine, amide, ether, ester, phosphate, borate, ketone, and aldehyde
It can be seen that it forms a complex with TFE and significantly raises the boiling point of TFE. In other words, these compounds have been shown to have significantly superior TFE absorption ability due to complex formation. It was confirmed that this boiling point increase was not due to azeotropy but to complex formation.

【table】

[Table] Example 2 The reflux boiling points of various fluorinated alcohols in a composition containing 65% by weight of 2-pyrrolidone and 35% by weight of various fluorinated alcohols are shown in Table 2. As is clear from this result, these fluorinated alcohols are
- It can be seen that the boiling point rises significantly in pyrrolidone and a complex is formed. It was confirmed that the boiling point increase in this case was not due to azeotropy but due to complex formation.

[Table] Reference Example 1 Figure 2 shows the vapor pressure temperature diagram of a composition consisting of 26.919% by weight of TFE as a refrigerant, 72.781% by weight of diethylene glycol monomethyl ether (hereinafter referred to as DME) as an absorbent, and 0.30% by weight of water. Indicated. Line A in Figure 2 shows the saturated vapor pressure of TFE at each temperature, and lines B ₁ , B ₂ , and B ₃ show the compositions with TFE/DME weight ratios of 30/70, 25/75, and 20/80, respectively. Although it is not shown in the figure, it is based on the values obtained by measuring the vapor pressure at each temperature.
It was also confirmed that the boiling point of TFE is 75°C and that of DME is approximately 196°C. However, in the absorption refrigeration cycle shown in Figure 1,
It was experimentally confirmed that an absorption refrigerator can be operated roughly as shown by the thick solid line when a composition of TFE/DME=27/73 (weight ratio) is enclosed and driven. That is, TFE flows into the generator (1) (second
Figure point a) An absorbent liquid (dilute liquid) with a low absorbent concentration with a TFE/DME weight ratio of 27/73 is generated, and this is approximately
It is heated to 117°C and TFE is vaporized and separated (point b in Figure 2) and sent to condenser 2. On the other hand, the absorbent concentration is approximately 81% by weight.
Absorbent liquid with high absorbent concentration (concentrated liquid)
is cooled through the heat exchanger 6 and flows into the absorber 5 (point c in Figure 2). TFE flowing into condenser 2
is cooled to about 5°C, liquefied, and supplied to the evaporator 3 at a pressure of about 19 mmHg via the pressure reducing device 4, and when vaporized there, it cools the objects around the evaporator 3 to about 5°C. Cooling. Vaporized TFE is absorbed in absorber 5
The inside of the evaporator 3 is maintained at approximately 19 mmHg, and the dilute liquid formed by absorbing TFE gas (point d in Figure 2) is absorbed in the heat exchanger 6. After exchanging heat with the concentrated liquid flowing into the vessel 5 and raising its temperature, it flows into the generator 1 again (point a in Figure 2). In such an absorption refrigeration cycle, the boiling point of TFE differs from that of DME by about 120°C, so azeotropy does not occur, and the analyzer 8 and rectifier 9 are used in the absorption refrigeration mechanism. No need for attachment,
Equipment configuration can be simplified. In addition, the characteristic feature of this invention is that the operating pressure of the absorption refrigerator is approximately 250 mmHg on the high pressure side where the generator 1 is located, and approximately 20 mmHg on the low pressure side where the evaporator 3 is located.
mmHg and all parts are lower than atmospheric pressure, and as with conventional ammonia-water systems and Freon-tetraethylene glycol dimethyl ether systems, the operating pressure is 10 to 20 Kg/cm ² on the high pressure side, and even on the low pressure side it is about 5
Unlike refrigerant systems that operate under high pressure conditions of Kg/ ^cm2 ,
There is no risk of liquid or gas leaking from the absorption refrigerator.
Furthermore, it is possible to reduce the strength of the structural equipment of the refrigeration machine and to simplify maintenance management. Furthermore, when the above composition is used, there is no crystallization of the absorption liquid under normal operating conditions of an absorption refrigerator, there is no extreme increase in viscosity, and operation in cold regions is not impossible. Also, condenser 2 and absorber 3
Since it can be air-cooled, there is no need for a water cooling mechanism or cooling tower like in conventional water-lithium bromide systems, making it possible to operate absorption chillers in areas with poor water conditions. In addition, in this example, the amount of
Although the experimental results are shown for an example in which the DME concentration difference is 8% by weight, this concentration and concentration difference are just one example, and it can be seen from the diagrams in Figure 2 that the same operation can be performed with other concentrations and concentration differences. This can be easily confirmed. Reference example 2 TFE26.838% by weight, DME72.562% by weight, water
0.299% by weight and 0.30% by weight of benzotriazole
A vapor pressure temperature diagram substantially the same as that in FIG. 2 was also obtained for the composition consisting of the following. Also, the amount of benzotriazole added is 0.03% by weight.
It was found that 0.5% by weight was effective. Reference example 3 TFE as refrigerant, N-methyl as absorbent
FIG. 3 shows vapor pressure temperature diagrams when 2-pyrrolidone is used at various concentrations. Line A in the figure is
Find the saturated vapor pressure of TFE at each temperature, and
B′ ₁ , B′ ₂ , and B′ ₃ have TFE/N-methyl-2-pyrrolidone weight ratios of 50/50, 40/60, and 40/60, respectively.
The values are shown based on the values obtained by measuring the vapor pressure of the 30/70 composition at various temperatures. Although not shown in the figure, the boiling point of TFE is 75℃, N-methyl-
It was also confirmed that the boiling point of 2-pyrrolidone is 202°C. However, in the absorption refrigeration cycle shown in Figure 1, the refrigerant
The weight ratio of TFE/N-methyl 2-pyrrolidone is
It was experimentally confirmed that the absorption refrigerator operates as shown by the thick solid line when the 48/52 composition is enclosed and operated. That is, TFE flows into generator 1 (third
Figure point a) A dilute solution with a weight ratio of TFE/N-methyl-2-pyrrolidone of 48/52 is produced, and this is heated to approximately 114°C.
The TFE is vaporized and separated (point b in Figure 3) and sent to the condenser 2. On the other hand, the concentrated liquid having an N-methyl-2-pyrrolidone concentration of approximately 60% by weight is cooled through a heat exchanger 6 and supplied to the absorber 5 (point C in Figure 3). The TFE that has flowed into the condenser 2 is cooled to about 50°C and liquefied, and is supplied to the evaporator 3 at a pressure of about 19 mmHg via the pressure reducing device 4, where it is vaporized.
The objects around the evaporator 3 are cooled to about 5°C. Since the vaporized TFE is absorbed by the concentrated liquid sprayed in the absorber 5, the inside of the evaporator 3 is maintained at approximately 19 mmHg, and the dilute liquid generated by absorbing the TFE gas (point d in Figure 3) is After exchanging heat with the concentrated liquid flowing into the absorber 5 in the heat exchanger 6 and raising the temperature, the liquid flows into the regenerator 1 again (point a in Figure 3). In such an absorption refrigeration cycle, there is a boiling point difference of approximately 130°C between the boiling points of TFE and N-methyl-2-pyrrolidone, as mentioned above, so azeotropy does not occur, and an analyzer is used in the absorption refrigeration machine configuration. 8 and rectifier 9 are no longer necessary, and the equipment configuration can be simplified. Furthermore, what is extremely characteristic about this invention is that the operating pressure of the absorption refrigerator is approximately 250 mmHg on the high pressure side where the generator 1 is located, and approximately 250 mmHg on the low pressure side where the evaporator 3 is located.
20mmHg, which is lower than atmospheric pressure in all parts, and even in conventional ammonia water systems and Freon-tetraethylene glycol dimethyl ether systems, where the operating pressure is 10 to 20Kg/cm2 on the high pressure side and about 5Kg/ ^cm2 on the low pressure side.
Unlike refrigerant systems that operate under high pressure conditions of Kg/ ^cm2 ,
There is no risk of liquid or gas leaking from the absorption refrigerator.
Furthermore, the strength of the components of the refrigerator can be reduced and maintenance management can be simplified. Furthermore, the composition of this example does not cause crystallization of the absorption liquid under normal operating conditions of an absorption refrigerator, does not cause an extreme increase in viscosity, and does not become impossible to operate in cold regions. Since the condenser 2 and absorber 3 can be air-cooled, there is no need for a water cooling mechanism or cooling tower like in conventional water-lithium bromide systems, making it possible to operate absorption chillers in areas with poor water conditions. be. In this example, N in the dilute solution and concentrated solution was
The experimental results are shown when the concentration difference of methyl-2-pyrrolidone is 8% by weight, but this concentration and concentration difference are just one example, and the diagram in Figure 3 shows that the same operation can be performed with other concentrations. This can be easily confirmed from Reference Example 4 TFE and DME were placed in a pressure-resistant glass tube with a breakable seal as shown in Figure 4 at a ratio of TFE/DMF = 25/75 (weight ratio), and 1% by weight of organic amines and metal pieces were added. (Piano wire), the cycle of cooling (-78°C) → degassing → 50°C was performed twice to degas the tube, and the glass tube was sealed. After that, it was left at a temperature of 175℃ for 3 weeks.
After cooling to 50°C, it was connected to a vapor pressure measuring device, the breaker pull seal was mechanically broken, and the vapor pressure was measured. The results are shown in Table 3, and it was found that the vapor pressure was not much different from that obtained when the 5 degassing cycles were performed, indicating that sufficient degassing was achieved even if the degassing conditions were slightly insufficient. At the same time, the corrosion state of the metal piece was observed based on changes in its appearance, and it showed an excellent corrosion inhibiting effect on Pinois wire.

[Table] Example 7 Add 1% by weight of the following organic amine to a mixture of TFE/DME = 25/75 (weight ratio), and distill the TFE using a Claisen flask. The amount of organic amine in the sample was determined and shown in Table 4.

[Table] As shown above, amines with a boiling point of 15℃ or less are TFE
Since it is also contained in the distillate, it can be seen that corrosion of metals (especially iron) in equipment from the generator to the evaporator is suppressed.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the basic cycle of a general absorption refrigerator; Figure 2 is a vapor pressure temperature diagram when TFE is used as the refrigerant and DME is used as the absorbent; Figure 3 is a diagram of the vapor pressure and temperature of the refrigerant. Vapor pressure temperature diagram when TFE is used as the absorbent and N-methyl-2-pyrrolidone is used as the absorbent; and Figure 4 shows the pressure-resistant glass tube used in Reference Example 4 for the heat resistance and vapor pressure measurement test. Cross-sectional view of (10...Breakable seal part;
11...sample input and tube sealing part; 12...connecting part to vapor pressure measuring device).

Claims (1)

[Scope of Claims] 1. At least one fluorinated alcohol refrigerant having 2 to 10 carbon atoms, which is liquid at room temperature and can become a vapor under normal pressure or reduced pressure when heated, and a refrigerant with a higher temperature than the refrigerant. A composition for an absorption refrigerator comprising at least one absorbent having a normal pressure boiling point and capable of absorbing the refrigerant (excluding diethylene glycol monomethyl ether). 2 The fluorinated alcohol has the following formula (),
() or (): (wherein, the group is R ¹ -CH ₂ -[Formula] and [Formula] are halogen-substituted hydrocarbon groups having one or more fluorine atoms and 2 to 10 carbon atoms) The composition according to claim 1, which is an alcohol, a fluorinated secondary alcohol, or a fluorinated tertiary alcohol. 3 The fluorinated primary alcohol is 2,2,2-trifluoro-1-ethanol, 2-monochloro-
2,2-difluoro-1-ethanol, 2,2-
Difluoro-1-ethanol, 2-monofluoro-1-ethanol, 3,3,3,2,2-pentafluoro-1-propanol, 3,3,2,2,
-Tetrafluoro-1-propanol, 4,4,
4,3,3,2,2-heptafluoro-1-butanol, 4,4,4,3,2,2-hexafluoro-1-butanol, 5,5,4,4,3,3,
2,2-octafluoro-1-pentanol,
5,5,5,4,4,3,2,2-octafluoro-1-pentanol, 7,7,6,6,5,
5,4,4,3,3,2,2-dodecafluoro-
1-heptanol, 2-(1,1,1-trifluoroethyl)-1-hexanol, 8,8,7,
7,6,6,5,5,4,4,3,3-dodecafluoro-1-octanol, 2-(pentafluoroethyl)-1-hexanol, 2-(1,1,
1-trifluoroethyl)-2-fluoro-1-
Hexanol, 2-(pentafluoroethyl)-
2-Fluoro-1-hexanol, 7,7,7-
Trifluoro-1-heptanol, 6,6,6-
Trifluoro-1-hexanol, 2,2,3,
3-tetrafluoro-1-hexanol, 2,
2,3,3-tetrafluoro-1-heptanol, 2,2,3,3-tetrafluoro-1-octanol, 6,6-difluoro-1-hexanol, 7,7-difluoro-1-heptanol,
8,8-difluoro-1-octanol, 2-
(pentafluorophenyl)ethanol, 2,3,
4,5,6-pentafluorobenzyl alcohol, 2-(2,3-difluorophenyl)ethanol, 3,3,3-trifluoro-2-(2,3
3. The composition according to claim 2, which is 3,3,3-trifluoro-2-(2,2-difluorocyclohexyl)-1-propanol. 4 The fluorinated secondary alcohol is 4,4,3,3,
1,1,1-heptafluoro-2-butanol,
1,1,1-trifluoro-2-octanol,
1,1,1-trifluoro-2-nonanol,
6, 6, 5, 5, 5, 4, 4, 3, 3, 2, 2-
decafluoro-1-methyl-1-hequinol,
6, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2-
The composition according to claim 2, which is undecafluoro-1-methyl-1-hexanol or 2,2,3,3,4,4,5,5-octafluoro-1-methyl-1-pentanol. thing. 5 The fluorinated tertiary alcohol is 7,7,7,6,
6,5,5,4,4,3,3,2,2-tridecafluoro-1,1-dimethyl-1-heptanol, 2,2,3,3-tetrafluoro-1,1-
Dimethyl-1-propanol, 1,1,1-trifluoro-2-phenyl-2-propanol,
1,1,1,3,3,3-hexafluoro-2-
Phenyl-2-propanol or 1,1,3,
3,3-hexafluoro-2-(p-tolyl)-
The composition according to claim 2, which is 2-propanol. 6. The composition according to any one of claims 1 to 5, wherein the fluorinated alcohol has a boiling point of 120°C or less. 7. The composition according to claim 3, wherein the fluorinated primary alcohol is 2,2,2-trifluoro-1-ethanol. 8. The composition according to claim 1, wherein the absorbent is an organic compound having electron-donating properties. 9. The composition according to claim 8, wherein the absorbent is an ether, an ester, a polyol, an amide, an amine, an imide, a ketone, an aldehyde, or a nitrile. 10 Ethers are represented by the formula (): R ⁷ (OCH ₂ CH ₂ )nOH () or polyethylene glycol monoalkyl ethers are represented by the formula (): R ⁷ (OCH ₂ CH ₂ )nOR ⁸ () polyethylene glycol dialkyl ether (wherein R ⁷ and R ⁸ are alkyl groups having 1 to 4 carbon atoms; n is an integer of 2 to 5; however, when n is 2 in formula (), R ⁷ is a carbon atom 10. The composition according to claim 9, which is an alkyl group having a number of 2 to 4. 11 Polyethylene glycol monoalkyl ether is diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, tetraethylene glycol monomethyl ether or tetraethylene glycol monopropyl ether The composition according to claim 10. 12 Polyethylene glycol dialkyl ether is diethylene glycol dimethyl ether,
11. The composition according to claim 10, which is diethylene glycol diethyl ether, diethylene glycol dipropyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dipropyl ether or tetraethylene glycol dipropyl ether. 13. The composition according to claim 9, wherein the amide is an alkyl-substituted lactam having 3 or more carbon atoms. 14. The composition according to claim 13, wherein the alkyl-substituted lactam having 3 or more carbon atoms is N-methyl-2-pyrrolidone or N-ethyl-2-pyrrolidone. 15. The composition of claim 1 containing 5 to 60% fluorinated alcohol and 40 to 95% absorbent, based on the weight of the composition. 16. The composition of claim 1 containing 0.05-1.0% water based on the weight of the composition. 17 Boiling point of 0.05-10% based on the weight of absorbent
The composition according to claim 1, which contains an organic amine having a temperature of 150°C or less. 18 In an absorption refrigeration system using a volatile refrigerant and an absorbent, at least one fluorinated alcohol refrigerant having 2 to 10 carbon atoms and which is liquid at room temperature and can become a vapor at normal pressure or reduced pressure when heated; An absorption refrigeration system using at least one type of absorbent (excluding diethylene glycol monomethyl ether) having a normal pressure boiling point higher than that of the refrigerant and capable of absorbing the refrigerant.