JPS5811035A - Stabilizing method for absorption type refrigerant composition - Google Patents

Abstract

PURPOSE:To stabilize an absorption refrigerant compsn. by adding epoxides to an absorption refrigerant compsn. consisting of ''Freon '' and tetraethylene glycol dimethylether. CONSTITUTION:Epoxides such as 1,2butyrene oxides are added to an absorption absorption refrigerant compsn. consisting of lower aliphat. chlorinated and fluorinated hydrocarbon such as trichlorofluoromethane, chlorodifluoromethane or the like and tetraethylene glycol dimethylether. Then, ''Freon '' which turns unstable by receiving the influenece of metals such as iron, copper or the like of the materials of refrigerating devices is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stabilizing an absorption refrigerant composition comprising a lower aliphatic chlorinated fluorinated hydrocarbon (hereinafter referred to as fluorocarbon) and tetraethylene glycol dimethyl ether.

Refrigerators are classified into compression type, absorption type, steam injection type, and adsorption type, among which compression type and absorption type are widely used on an industrial scale. In a compression type refrigerator, the refrigerant undergoes a cycle of evaporation, compression, condensation, and expansion and then undergoes refrigeration, while in an absorption type refrigerator, refrigeration is performed by a cycle of evaporation, absorption, regeneration, and condensation. Various types of fluorocarbons, such as dichlorodifluoromethane and chlorodifluoromethane, are used as refrigerants because they are less toxic, nonflammable, and inert to metals. In absorption refrigerators, when the refrigerant is chlorofluorocarbon, an organic absorbent such as tetraethylene glycol dimethyl ether is generally used as the absorbent.

According to recent studies by the present inventors, it has been found that decomposition of fluorocarbons, which was unthinkable in compression refrigerators, occurs in absorption refrigerators that use tetraethylene glycol dimethyl ether as an absorbent. . After further investigation, we found that the maximum temperature during refrigerant circulation is quite different between the compression type and the absorption type, and that the absorption type is affected by the absorbent. It was discovered that even active fluorocarbons become unstable due to the influence of iron, copper, aluminum, etc. used as materials for refrigeration equipment. The inventors of the present invention have conducted various studies to stabilize the fluorocarbon refrigerant under the coexistence of the absorbent and metal metals in the absorption refrigerator and at high temperatures, and have found that the addition of epoxides is effective. I was able to find out.

That is, the method of the present invention relates to a method for stabilizing an absorption refrigerant composition, which is characterized by adding epoxides to an absorption refrigerant composition consisting of fluorocarbons and tetraethylene glycol dimethyl ether. As a result of further studies, it was discovered that a combination of epoxides and phenols is more effective in achieving the above objective.

That is, the method of the present invention also provides a method for stabilizing an absorption refrigerant composition, which is characterized by adding epoxides and phenols to an absorption refrigerant composition consisting of fluorocarbons and tetraethylene glycol dimethyl ether.

The stabilized fluorocarbons include lower aliphatic chlorinated fluorinated hydrocarbons commonly used as refrigerants. ! l),
) dichlorofluoromethane, dichlorodifluoromethane, chlorotrifluoromethane, chlorodifluoromethane, trichlorotrifluoroethane, octafluorocyclobutane, and various azeotropic compositions such as chlorodifluoromethane and chloropentafluoroethane. Chlorodifluoromethane and the like are commonly used as absorption refrigerants. Organic solvents that absorb such fluorocarbons, so-called absorbers, absorb a large amount of fluorocarbons in absorbers.
For the regenerator, it is preferable to use a material that releases a large amount of fluorocarbons and whose solubility changes greatly depending on the operating conditions between the absorber and the regenerator, usually tetraethylene glycol dimethyl ether.

Table 1 below shows the stability of the refrigerant chlorodifluoromethane in the presence of the absorbent tetraethylene glycol dimethyl ether and iron, copper, and aluminum at a temperature of 170°C. In the absence of an absorbent, almost no decomposition of fluorocarbons occurs, and HOA + HF is generated by the decomposition of fluorocarbons.
The detected amounts of these are very small, less than 3 ppm and less than 1 ppm, respectively. However, it can be seen that the presence of an absorbent intensifies the decomposition of fluorocarbons. By the method of the present invention,
Decomposition could be suppressed by adding 1,2-butylene oxide as an epoxide, or by further adding 2,6-di-t-butyl-P-cresol as a phenol. Epoxides include at least one adjacent evolene oxide and 2,3-butylene oxide in seven molecules.

Epichlorohydrin, styrene oxide, butyl glycidyl ether & phenyl glycidyl ether, glycidol, etc. are preferred. A particularly preferred epoxide is 1,2-butylene oxide. The amount of such epoxides added can vary over a wide range, but is usually 0.01 to 50% by weight based on the refrigerant Freon.
The amount is preferably between 0.005 and 10% by weight. Phenols include phenol, cresol, butylphenol, thymol, 2゜6-di-t-butyl-
p-cresol, eugenol, ineugenol, θ
-Methoxyphenol, p-methoxyphenol, catechol.

Examples include t-butylcatechol, salicylic acid esters, bisphenol A or other phenol derivatives, preferably θ-methoxyphenol, eugenol,
t-butylcatechol, 2,6-di-t-butyl-p-
Cresol etc. Although the amount added can vary over a wide range, it is usually n, 005 to 005 for the refrigerant Freon.
! About 1.0% by weight is adopted, preferably n, o1~
1.0 weight t% is adopted. Such stabilizers.

The key is not to impede the purpose of the invention! Two or more types of 71 epoxides and two or more types of phenols can be used.

Next, embodiments of the present invention will be described in more detail, but it goes without saying that the present invention is not limited by such explanations.

<Refrigerant stability test> 1-1 Test equipment/test container 8US 516 pressure container internal volume 100
-1 Pressure resistance 100 b/car” G ・Thermostatic chamber Hot air forced circulation type, accuracy 170℃±1℃ 1-2 Test conditions/Temperature 170℃ ・Duration 7 days ・Refrigerant Freon 22 (chlorodifluoromethane) ・Absorbent Tetraethylene glycol dimethyl ether Refrigerant: Absorbent addition amount 50r:50F Coexisting metals Iron, copper, aluminum (25X 50X rL
5 tax) ・Stabilizer 1.2-butylene oxide or 1.2
-Butylene oxide/2゜6-di-t-butyl-p-fresol Under the above test equipment and conditions, HF was measured by the Alfluorone absorption 4 degree method, A g, N 01 was measured by the nephelometric method.
) HOj was measured and the degree of decomposition of Freon 22 was estimated. The test results are shown in Table 1 below.

Table 1

Claims (1)

[Scope of Claims] 1) A method for stabilizing an absorption refrigerant composition, which comprises adding epoxides to an absorption refrigerant composition comprising a lower aliphatic chlorinated fluorinated hydrocarbon and tetraethylene glycol dimethyl ether. 2) Epoxides and phenols in an absorption refrigerant composition consisting of lower aliphatic chlorinated fluorinated hydrocarbons and tetraethylene glycol dimethyl ether color? 1. A method for stabilizing an absorption refrigerant composition, the method comprising: