Compound stabilizer, preparation method thereof, refrigerating machine oil and working fluid composition for refrigerating machine

Abstract

The invention relates to the field of refrigerating systems, and discloses a compound stabilizer, a preparation method thereof, refrigerating machine oil and a working fluid composition for a refrigerating machine. The compound stabilizer comprises a compound with a structure as shown in a formula 1 and a compound with a structure as shown in a formula 2, wherein R1, R2, R4 and R5 are independently selected from hydrogen, alkyl, aromatic hydrocarbon, substituted alkyl and substituted aromatic hydrocarbon; r3 is selected from alkylene and aromatic hydrocarbon; a is the degree of polymerization and ranges from 2 to 10; and R6, R7 and R8 are independently selected from alkyl, aromatic hydrocarbon, substituted alkyl and substituted aromatic hydrocarbon. The invention provides a chemical stabilizer composition used in combination with an HFO refrigerant, the stabilizer composition comprises a phenolic ester compound and a phosphite ester compound with specific structures, and the phenolic ester compound and the phosphite ester compound are synergistically used in refrigerating machine oil to show excellent decomposition and oxidation resistance; therefore, the stability of the HFO refrigerant in the working fluid for the refrigerating machine is improved, and the reliable life cycle of a refrigerating system is prolonged. # imgabs0 #

Description

Technical Field

[0001] The present application relates to the field of refrigeration systems, and in particular to a composite stabilizer and a preparation method thereof, as well as a refrigeration oil and a working fluid composition for a refrigeration machine. Background Art

[0002] Refrigerant is the working substance that circulates in the refrigeration system. Through the vapor compression cycle, the refrigerant transfers heat from the low temperature side to the high temperature side. With the development of technology and the improvement of human cognition, refrigerants have undergone many changes, from CFC refrigerants to HCFC, and then to HFC, natural refrigerants, and HFO. The purpose is to find low GWP, ODP environmentally friendly, high safety performance, and economical refrigerants;

[0003] The GWP of R454B in HFO is lower than that of R410A in HFC, but double bonds are common in HFO components, and the chemical stability is poor. At extreme temperatures or with other compounds in the contaminated system, chemical reactions occur to produce unwanted byproducts, such as the generation of fluoric acid and trifluoroacetic acid by the refrigerant and the water in the system. When the refrigerant generates compounds with excess oxygen, oxidizing chemicals or free radicals, the refrigerant may degrade and reduce the reliability of the compressor. In the prior art, there are reports on the use of antioxidants 2,6-di-tert-butyl-4-di-tert-butylmethylphenol and acid scavenger CGE to improve the stability of HFOs such as R454B, but phenolic antioxidants are unstable under conditions of use above 100°C. Similarly, some terpene compound stabilizers also have the problem of being easily decomposed at high temperatures. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a composite stabilizer and a preparation method thereof, so that the composite stabilizer is adapted to HFO refrigerants and can solve the problems of HFO refrigerants due to the presence of unsaturated bonds, poor chemical stability, and easy decomposition and oxidation under high temperature and high pressure.

[0005] Another object of the present application is to provide a refrigeration oil and a working fluid composition for a refrigeration machine based on the composite stabilizer described in the present application.

[0006] In order to achieve all or part of the above objectives, as a first aspect of the present application, a composite stabilizer is provided, comprising a compound having a structure shown in Formula 1 and a compound having a structure shown in Formula 2;

[0007]

[0008] Among them, R1, R2, R4, and R5 are each independently selected from hydrogen, alkyl, aromatic hydrocarbon, substituted alkyl, and substituted aromatic hydrocarbon; R3 is selected from alkylene and aromatic hydrocarbon; a is the degree of polymerization, ranging from 2 to 10; R6, R7, and R8 are each independently selected from alkyl, aromatic hydrocarbon, substituted alkyl, and substituted aromatic hydrocarbon.

[0009] Optionally, in the structural compound represented by Formula 1, R1, R2, R4, and R5 are each independently selected from hydrogen, an alkyl group of C1 to C8; R3 is selected from an alkylene group of C1 to C4, and an aromatic hydrocarbon group; a is the degree of polymerization, ranging from 2 to 10.

[0010] Optionally, in the structural compound represented by Formula 2, R6, R7, and R8 are each independently selected from a hydrocarbon group of C6 to C18.

[0011] Optionally, the mass ratio of the compound having the structure represented by Formula 1 to the compound having the structure represented by Formula 2 is 1:3 to 3:4.

[0012] Further optionally, the structural compound represented by Formula 1 comprises any one or more of the following compounds:

[0013]

[0014] Further optionally, the structural compound shown in Formula 2 comprises any one or more of the following compounds:

[0015]

[0016] As a second aspect of the present application, a method for preparing the composite stabilizer is provided, comprising:

[0017] Dialkylphenol, phenol or diaromatic phenol is reacted with methyl acrylate under the catalysis of sodium methoxide to generate a phenol ester intermediate, and the phenol ester intermediate and polyalkyl glycol / polyaromatic glycol are reacted with sodium dithionite to generate a compound of the structure shown in Formula 1;

[0018] Phosphorous acid reacts with alcohol under acidic or alkaline catalyst conditions to generate a compound of structure shown in formula 2;

[0019] The compound having the structure shown in Formula 1 and the compound having the structure shown in Formula 2 are mixed to obtain the composite stabilizer.

[0020] As a third aspect of the present application, a refrigeration oil is provided, comprising a base oil and the composite stabilizer described in any one of the schemes of the present application.

[0021] Optionally, the refrigeration oil includes a base oil, the composite stabilizer described in any one of the schemes of the present application, and one or more additives selected from anti-wear agents, acid scavengers, metal deactivators, and anti-foaming agents.

[0022] As a fourth aspect of the present application, a fluid composition for a refrigerator is provided, comprising a refrigerant and the refrigerator oil described in any one of the schemes of the present application.

[0023] The present application provides a chemical stabilizer composition used in combination with HFO refrigerants, especially R454B refrigerant. The stabilizer composition comprises a phenolic ester compound and a phosphite compound of a specific structure. The synergistic use of the two in refrigeration oil can exhibit excellent anti-decomposition and oxidation performance, thereby improving the stability of the HFO refrigerant in the working fluid of the refrigerator and the reliability life cycle of the refrigeration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application.

[0025] Figure 1-Figure 5 Shown are the infrared spectra of Formula 1-1, Formula 1-2, Formula 1-3, Formula 2-1, and Formula 2-2, respectively. DETAILED DESCRIPTION

[0026] The present application discloses a composite stabilizer and a preparation method thereof, as well as a refrigeration oil and a working fluid composition for a refrigeration machine. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all deemed to be included in this application. The products and processes described in this application have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the products and processes described herein without departing from the content, spirit and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] It should be noted that, in this article, if relational terms such as "first" and "second", "step 1" and "step 2", and "(1)" and "(2)" appear, they are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements. At the same time, the embodiments in this application and the features in the embodiments may be combined with each other without conflict.

[0028] HFO refrigerants generally have unsaturated bonds, poor chemical stability, and are easily decomposed under high temperature and high pressure. For example, R454B is a mixture of R32 and R1234yf, where R1234yf is CF3CF=CH2. At present, antioxidants BHT and acid scavengers E-10P are usually added to refrigeration oils to play an antioxidant and anti-hydrolysis role, but there are no additives for the easy decomposition of HFO refrigerants. Therefore, conventional refrigeration oils are still relatively poor in stability in terms of performance indicators such as acid value, oxidation induction period, chromaticity, metal rod appearance, and acid radical ions when used with HFO refrigerants. Based on this, in the first aspect of the present application, a composite stabilizer is provided, including a structural compound shown in Formula 1 and a structural compound shown in Formula 2;

[0029]

[0030] Among them, R1, R2, R4, and R5 are each independently selected from hydrogen, alkyl, aromatic hydrocarbon, substituted alkyl, and substituted aromatic hydrocarbon; R3 is selected from alkylene and aromatic hydrocarbon; a is the degree of polymerization, ranging from 2 to 10; R6, R7, and R8 are each independently selected from alkyl, aromatic hydrocarbon, substituted alkyl, and substituted aromatic hydrocarbon.

[0031] The antioxidant in the present application is a high molecular weight phenolic ester antioxidant of the structure shown in Formula 1. The compound contains two -OH groups. Compared with the monophenolic antioxidant BHT, it has a better antioxidant effect. Its mechanism of action is that the phenolic group loses the oxygen radical of the H atom and reacts with other free radicals to consume the alkyl radicals and peroxide radicals. The structural compound shown in Formula 2 in the present application is a phosphite, which has excellent reducibility and can effectively terminate and inhibit the decomposition and polymerization of unsaturated bond components in HFO refrigerants, such as the decomposition and polymerization of R1234yf in R454B, and can also improve the stability of refrigeration oil in synergy with the structural compound shown in Formula 1.

[0032] In certain embodiments of the present application, in the structural compound shown in Formula 1, R1, R2, R4, and R5 are each independently selected from hydrogen, C1-C8 alkyl; R3 is selected from C1-C4 alkylene and aromatic hydrocarbon, and the alkylene and aromatic hydrocarbon can be substituents formed by losing one hydrogen each on different C, or losing two hydrogens on the same C; a is the degree of polymerization, ranging from 2-10. In some other embodiments of the present application, in the structural compound shown in Formula 1, R1, R2, R4, and R5 are each independently selected from C1-C8 straight-chain alkyl, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl; R3 is selected from C1-C4 straight-chain alkylene, such as methylene, ethylene, propylene, and butylene; a is the degree of polymerization, ranging from 2-10, such as 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0033] In certain embodiments of the present application, in the structural compound represented by Formula 2, R6, R7, and R8 are each independently selected from a C6-C18 hydrocarbon group, and the hydrocarbon group includes an aromatic hydrocarbon group, an alkane hydrocarbon group, an alkene hydrocarbon group, and an alkyne hydrocarbon group; in other embodiments of the present application, the aromatic hydrocarbon group is selected from a phenyl group or a phenyl group arbitrarily substituted with a C1-C5 alkyl group, and the alkane hydrocarbon group, the alkene hydrocarbon group, and the alkyne hydrocarbon group are straight-chain C6-C18 hydrocarbon groups.

[0034] In certain embodiments of the present application, the mass ratio of the structural compound represented by Formula 1 to the structural compound represented by Formula 2 is 1:3 to 3:4, for example, 1:3, 3:4, 2:3, etc.; when the ratio is lower than the said range, the structural compound represented by Formula 2 accounts for a large proportion, has a strong reducing ability, but has a poor antioxidant ability, and when the ratio is higher than this ratio, the structural compound represented by Formula 1 accounts for a large proportion, the stabilizer has a strong antioxidant ability, but a poor reducing ability, and the best antioxidant / reducing ability can be achieved within the range of 1:3 to 3:4.

[0035] In certain embodiments of the present application, the structural compound represented by Formula 1 comprises any one or more of the following compounds:

[0036]

[0037]

[0038] In certain embodiments of the present application, the structural compound represented by Formula 2 comprises any one or more of the following compounds:

[0039]

[0040] In a second aspect of the present application, a method for preparing the composite stabilizer is provided, comprising:

[0041] Dialkylphenol, phenol or diaromatic phenol is reacted with methyl acrylate under the catalysis of sodium methoxide to generate a phenol ester intermediate, and the phenol ester intermediate and polyalkyl glycol / polyaromatic glycol are reacted with sodium dithionite to generate a compound of the structure shown in Formula 1;

[0042] Phosphorous acid reacts with alcohol under acidic or alkaline catalyst conditions to generate a compound of structure shown in formula 2;

[0043] The compound having the structure shown in Formula 1 and the compound having the structure shown in Formula 2 are mixed to obtain the composite stabilizer.

[0044] Wherein, the alkyl substituents and aromatic substituents in the dialkylphenol and diaromatic phenol are determined according to R1, R2, R4, and R5, and these substituents are located at the 2nd and 6th positions of the benzene ring. For example, 2,6-dimethylphenol, 2-ethyl-6-methylphenol, and 2,6-diethylphenol are used as reaction raw materials, and R1, R2, R4, and R5 are respectively selected from methyl and ethyl. The polyalkylene glycol and polyaromatic glycol are determined according to the alkylene and aromatic hydrocarbon groups selected by R3. For example, polyethylene glycol and polypropylene glycol are used as reaction raw materials, and R3 is selected from propylene and ethylene. The value of the degree of polymerization is determined according to the degree of polymerization of the polyalkylene glycol and polyaromatic glycol reaction raw materials used.

[0045] The alcohol is determined according to the hydrocarbon groups selected by R6, R7, and R8. For example, if 3-methylphenol and n-dodecyl alcohol are used as the reaction raw materials, then R6, R7, and R8 are selected to be methyl-substituted phenyl and C12 straight-chain alkyl, respectively.

[0046] In certain embodiments of the present application, the preparation method includes but is not limited to selecting a suitable solvent, such as water, selecting a suitable reaction temperature and time, selecting a suitable protective gas protection, selecting a suitable reaction vessel and equipment, etc. according to the preparation needs.

[0047] In certain embodiments of the present application, the method for preparing the compound of the structure shown in Formula 1 comprises:

[0048] Dialkylphenol, phenol or diaromatic phenol is first reacted with sodium methoxide at 165°C under nitrogen protection, and then methyl acrylate is added to react at 140°C to generate a phenol ester intermediate. The phenol ester intermediate and polyalkyl glycol / polyaromatic glycol are reacted at 80°C under the catalysis of sodium dithionite to generate a structural compound shown in Formula 1.

[0049] In certain embodiments of the present application, the method for preparing the compound of the structure shown in Formula 2 comprises:

[0050] Phosphorous acid reacts with alcohol under the conditions of acidic or alkaline catalyst and nitrogen protection at 100-120° C. to generate a compound of the structure shown in formula 2;

[0051] In certain embodiments of the present application, the acidic catalyst is selected from an organic acid or an inorganic acid, such as sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, etc.; the alkaline catalyst is selected from an organic base or an inorganic base, such as sodium hydroxide, potassium hydroxide, etc.; the products synthesized under the two catalysts are the same, and the difference lies in the slight difference in the post-treatment steps.

[0052] In a third aspect of the present application, a refrigeration oil is provided, comprising a base oil and the composite stabilizer described in any one of the schemes of the present application.

[0053] In certain embodiments of the present application, the refrigeration oil includes a base oil, the composite stabilizer described in any one of the schemes of the present application, and one or more additives selected from anti-wear agents, acid scavengers, metal deactivators, and anti-foaming agents.

[0054] When the refrigeration oil is prepared, the total amount of base oil, acid scavenger, composite stabilizer, anti-wear agent and metal deactivator is 100%, and the anti-foaming agent is additionally added on this basis.

[0055] In certain embodiments of the present application, the dosage of the composite stabilizer is at least 1%, and the optimal dosage is 1% to 3%. If the dosage is too low, the antioxidant and anti-decomposition effects are not obvious, while if the dosage is too high, it will lead to side effects such as increased costs and difficulty in dissolving.

[0056] In certain embodiments of the present application, the base oil is a POE ester oil, which is a polyol ester formed by esterifying a polyol with an organic acid. The polyol is selected from one or more of pentaerythritol, dipentaerythritol, neopentyl glycol, trimethylolpropane, and trimethylolethane, and the organic acid is selected from one or more of C4-C18 straight or branched, saturated or unsaturated fatty acids, maleic anhydride, terephthalic acid, and adipic acid; further, the fatty acid is selected from one or more of n-butyric acid, 2-methylpropionic acid, n-pentanoic acid, 2-methylbutyric acid, n-hexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 3-ethylhexanoic acid, n-nonanoic acid, 2-methyloctanoic acid, 3-methyloctanoic acid, 4-methyloctanoic acid, 2-ethylheptanoic acid, 3-ethylheptanoic acid, 4-ethylheptanoic acid, and 3,5,5-trimethylhexanoic acid. The amount of base oil is based on the total amount of refrigeration oil (excluding antifoaming agent) and can be selected as 90wt% or more.

[0057] In certain embodiments of the present application, the anti-wear agent is selected from one or more of phosphate compounds, phosphite compounds, organic sulfides, phosphorus-nitrogen complex compounds, sulfur-phosphorus-nitrogen complex compounds, and organic chlorides, and the amount of the anti-wear agent is based on the total amount of the refrigeration oil (excluding the anti-foaming agent) and can be selected to be 0.1% to 2.0wt%;

[0058] In certain embodiments of the present application, the metal deactivator is selected from one or more of benzotriazole derivatives and thiadiazole derivatives, and the amount of the metal deactivator is based on the total amount of the refrigeration oil (excluding the antifoaming agent) and can be selected from 0.01wt% to 0.1wt%;

[0059] In certain embodiments of the present application, the acid scavenger is one or more of neodecanoic acid glycidyl ether and tert-butylphenyl glycidyl ether; based on the total amount of refrigeration oil (excluding antifoaming agent), the content of the acid scavenger is 0.1-2.0wt%;

[0060] In certain embodiments of the present application, the antifoaming agent is selected from one or more of silicon antifoaming agents and non-silicon antifoaming agents. The silicon antifoaming agent may be dimethyl silicone oil; the non-silicon antifoaming agent may be selected from one or more of homopolymers or copolymers of acrylates and homopolymers or copolymers of methacrylates. The amount of the antifoaming agent used is based on the total amount of the refrigeration oil and the antifoaming agent, and may be selected from 10ppm to 100ppm.

[0061] The refrigeration oil provided in the present application usually exists in the form of a working fluid composition for a refrigerator mixed with a refrigerant in a refrigeration system. Therefore, in the fourth aspect of the present application, a fluid composition for a refrigerator is provided, comprising a refrigerant and the refrigeration oil described in any one of the schemes of the present application.

[0062] In certain embodiments of the present application, the refrigerant is selected from one or more HFO refrigerants, including but not limited to 1,2,3,3,3-pentafluoro-1-propylene, 1,2,3,3-tetrafluoro-1-propylene, 1,3,3,3-tetrafluoro-1-propylene, 2,3,3-trifluoro-1-propylene, 1,1,2-trifluoro-1-propylene, 1,3,3-trifluoro-1-propylene, 1,1,2,3,4-pentafluoro-2-butene, 3,3,4,4-tetrafluoro-1-butene, 1,1,1,2-tetrafluoro-2-butene, 1,1,1,2,3,4,4,5,5,5-decafluoro-2-pentene, etc. The content of the refrigeration oil in the working fluid composition is not particularly limited. Relative to 100 parts by mass of the refrigerant, preferably 1 to 500 parts by mass of the refrigeration oil is used, and more preferably 2 to 400 parts by mass of the refrigeration oil is used.

[0063] In each group of comparative experiments provided in this application, unless otherwise specified, other experimental conditions, materials, etc. are kept consistent except for the differences indicated in each group, so as to provide comparability. In addition, all materials used in this application can be purchased through commercial channels.

[0064] The following further describes a composite stabilizer and a preparation method thereof, as well as a refrigeration oil and a working fluid composition for a refrigeration machine provided in the present application.

[0065] Example 1: Preparation of an exemplary compound of the structure shown in Formula 1

[0066] (1) Preparation of compound of formula 1-1

[0067] 2,6-Dimethylphenol and 2 mol / L sodium methoxide were placed in a round-bottom flask. Under nitrogen protection, the reaction temperature of the mixture was set at 165°C for 1.0 hour. Then, methyl acrylate was added and stirred at 140°C for 2 hours to obtain a phenol ester intermediate. Polypropylene glycol and catalyst sodium dithionite were added to the flask and stirred at 80°C for 1 hour. The product was obtained by rotary evaporation. Its infrared spectrum is shown in FIG. Figure 1 .

[0068]

[0069] (2) Preparation of compound of formula 1-2

[0070] 2-Ethyl-6-methylphenol and 2 mol / L sodium methoxide were placed in a round-bottom flask. Under nitrogen protection, the reaction temperature of the mixture was set at 165°C for 1.0 hour. Then, methyl acrylate was added and stirred at 140°C for 2 hours to obtain a phenol ester intermediate. Polyethylene glycol and catalyst sodium dithionite were added to the flask and stirred at 80°C for 1 hour. The product was obtained by rotary evaporation. Its infrared spectrum is shown in FIG. Figure 2 .

[0071]

[0072] (3) Preparation of compound of formula 1-3

[0073] 2,6-Diethylphenol and 2 mol / L sodium methoxide were placed in a round-bottom flask. Under nitrogen protection, the reaction temperature of the mixture was set at 165°C for 1.0 hour. Then, methyl acrylate was added and stirred at 140°C for 2 hours to obtain a phenol ester intermediate. Polyethylene glycol and catalyst sodium dithionite were added to the flask and stirred at 80°C for 1 hour. The product was obtained by rotary evaporation. Its infrared spectrum is shown in FIG. Figure 3 .

[0074]

[0075] Example 2: Preparation of an exemplary compound of the structure compound represented by Formula 2

[0076] (1) Preparation of compound of formula 2-1

[0077] Phosphorous acid (H3PO3) and 3-methylphenol (m-methylphenol) react in the presence of p-toluenesulfonic acid as a catalyst under nitrogen protection at a temperature of 100-120°C for 4-8 hours to generate 3-methyltriphenylphosphite (the structural compound shown in Formula 2-1). The infrared spectrum is shown in Figure 4 .

[0078]

[0079] (2) Preparation of compound of formula 2-2

[0080] n-Dodecanol and phosphorous acid react under the condition of p-toluenesulfonic acid as catalyst at a temperature of 100-120°C for 4-8 hours to generate a compound of the structure shown in formula 2-2. The infrared spectrum is shown in Figure 5 .

[0081]

[0082] Example 3: Example composite stabilizer

[0083] The compounds prepared in Example 1 and Example 2 were mixed to prepare the composite stabilizer of the present application, as shown in Table 1 below;

[0084] Table 1

[0085]

[0086]

[0087] Experimental example:

[0088] (1) Stability test

[0089] According to JIS K2211-09 (autoclave test), this test method adds a certain amount of distilled water to the refrigeration oil, mixes evenly until the water content is 1000ppm, takes 30g of the water-containing refrigeration oil and adds it to the autoclave, seals in the catalyst (iron rod, copper rod, aluminum rod), uses a vacuum pump to evacuate the air in the autoclave, and then seals in 15g of refrigerant (such as R454B), and keeps it at 150℃ for 168h. Determine and calculate the acid value (mg KOH / g) of the oil sample after the test and observe whether the metal appearance changes.

[0090] (2) Chromaticity test

[0091] Refer to GB / T 6540 and use the ASTM standard color chart to compare the oil sample with the standard numbers arranged and numbered from very light gray to very dark red. The standard color that is most consistent with the color of the oil is the standard number of the oil.

[0092] (3) Acid ion test

[0093] Referring to the method of ASHRAE Standard 1997-2007, which uses the amount of free fluoride as an indicator, the oil samples after use were analyzed for acid radical ion F using ion chromatograph IC-DIONEX500, detector: conductivity detector, chromatographic column Anion AS15, mobile phase 1.7mM NaHCO3 / 1.8mMNa2CO3. - PO4 3- Content test.

[0094] (4) Oxidation stability test

[0095] With reference to ASTM D 6186-98, the oxidation induction period of lubricating oil was determined by pressure differential scanning calorimetry (PDSC) to test the oxidation induction period of refrigerating machine oil. The test pressure was 3.5 MPa. The sample weight was 3.0 ± 0.2 mg. Oxygen with a purity of > 99.5% was used. The oxygen flow rate was 100 ml / min.

[0096] (5) Refrigerating machine oil and refrigerating machine working fluid composition

[0097] ① Experimental group of this application:

[0098] The raw material alcohol in the base oil is pentaerythritol and dipentaerythritol, the organic acid is isovaleric acid, adipic acid and isooctanoic acid, and the base oil is synthetic ester POE oil;

[0099] The additives in refrigeration oil are as follows:

[0100] Additive A: composite stabilizer of Table 1;

[0101] Additive B: antifoaming agent 2-methylsilane;

[0102] Additive C: metal deactivator Irgamet 39;

[0103] Additive D: anti-wear agent T306;

[0104] Additive E: acid scavenger E-10P;

[0105] The refrigerant is R454B.

[0106] ②Control group:

[0107] The raw material alcohol in the base oil is pentaerythritol and dipentaerythritol, the organic acid is isovaleric acid, adipic acid and isooctanoic acid, and the base oil is synthetic ester POE oil;

[0108] The additives in refrigeration oil are as follows:

[0109] Additive B: antifoaming agent 2-methylsilane;

[0110] Additive C: metal deactivator Irgamet 39;

[0111] Additive D: anti-wear agent T306;

[0112] Additive E: Acid scavenger E-10P

[0113] The refrigerant is R454B.

[0114] Table 2 Experimental groups 1-6 and their performance parameters

[0115]

[0116]

[0117] Table 3 Control groups 1-8 and their performance parameters

[0118]

[0119] Combining the data in Table 2 and Table 3, it can be seen that the refrigeration oil used in Control Groups 1 to 3 is a solution in which the composite stabilizer of the present application is not added, or only one compound in the composite stabilizer is added. From the perspective of various indicators, it is obviously inferior to the experimental group with the composite stabilizer of the present application:

[0120] Among them, the appearance of the metal rods of the control groups 1-3 were all above grade 2a, while the grades of the experimental groups were all grade 1a; the acid values ​​of the control groups 1-3 were 0.20-0.32 mgKOH / g, while the acid values ​​of the experimental groups were all below 0.1 mgKOH / g; except for the control group 2 which reached about 30 minutes due to the use of the structural compound shown in formula 1 of the present application, the oxidation induction period of the control groups 1-3 was less than 20 minutes, while the oxidation induction period of the experimental groups was more than 35 minutes, and the highest could reach 39 minutes; the chromaticity values ​​of the control groups 1-3 were 2.0-3.0, while the chromaticity values ​​of the experimental groups were all 1.0; although the acid scavengers were added to the control groups 1-3, the acid radical ions were generally higher, while the acid radical ions of the experimental groups were all 0; the above indicators fully illustrate that the two compounds in the composite stabilizer of the present application have a synergistic effect, strong antioxidant ability, and can effectively reduce the decomposition of the acidic components and refrigerants in the refrigeration oil composition.

[0121] Control group 4, control group 5, control group 6 and control group 7 are all schemes that do not meet the optimal ratio and dosage of the present application in terms of the ratio or total amount of the two compounds. It can be seen that whether the ratio of the two compounds is lower than the control group 6 of 1:3 to 3:4 of the present application, or higher than the control group 7 of 1:3 to 3:4 of the present application, it only reaches the same standard of the present application in very few indicators, but most of the performance indicators are still poor. The total dosage of control group 4 is less than 2%, and the antioxidant and anti-decomposition effects are not obvious due to the low addition amount. The total dosage of control group 5 is higher than 5%, and the various indicators are comparable to the present application in terms of performance, but this will lead to side effects such as increased costs and difficulty in dissolving.

[0122] The comparison of the above schemes shows that the addition of the two compounds in the composite stabilizer of the present application has a synergistic effect, exhibits better antioxidant performance, small chromaticity value, small acid value, and better overall performance.

[0123] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A composite stabilizer, characterized in that: Including the structural compound shown in Formula 1 and the structural compound shown in Formula 2; R1, R2, R4, and R5 are each independently selected from hydrogen, alkyl, aromatic hydrocarbon, substituted alkyl, and substituted aromatic hydrocarbon; R3 is selected from alkylene and aromatic hydrocarbon; a is the degree of polymerization, ranging from 2 to 10; R6, R7, and R8 are each independently selected from alkyl, aromatic hydrocarbon, substituted alkyl, and substituted aromatic hydrocarbon.

2. The composite stabilizer according to claim 1, characterized in that In the structural compound represented by formula 1, R1, R2, R4, and R5 are independently selected from hydrogen and C1-C8 alkyl groups; R3 is selected from C1-C4 alkylene groups and aromatic hydrocarbon groups; a is the degree of polymerization, ranging from 2-10.

3. The composite stabilizer according to claim 1, characterized in that R6, R7, and R8 are each independently selected from a C6 to C18 hydrocarbon group.

4. The composite stabilizer according to claim 1, characterized in that The mass ratio of the compound represented by formula 1 to the compound represented by formula 2 is 1:3 to 3:

4.

5. The composite stabilizer according to any one of claims 1 to 4, characterized in that: The structural compound represented by Formula 1 includes any one or more of the following compounds:

6. The composite stabilizer according to any one of claims 1 to 4, characterized in that: The structural compound shown in Formula 2 includes any one or more of the following compounds:

7. The method for preparing the composite stabilizer according to claim 1, characterized in that: include: Dialkylphenol, phenol or diaromatic phenol is reacted with methyl acrylate under the catalysis of sodium methoxide to generate a phenol ester intermediate, and the phenol ester intermediate and polyalkyl glycol / polyaromatic glycol are reacted with sodium dithionite to generate a compound of the structure shown in Formula 1; Phosphorous acid reacts with alcohol under acidic or alkaline catalyst conditions to generate a compound of structure shown in formula 2; The compound having the structure shown in Formula 1 and the compound having the structure shown in Formula 2 are mixed to obtain the composite stabilizer.

8. A refrigeration oil, characterized in that: The invention comprises a base oil and the composite stabilizer according to any one of claims 1 to 6.

9. The refrigerating machine oil according to claim 8, characterized in that The invention comprises base oil, the composite stabilizer according to any one of claims 1 to 6, and one or more additives selected from anti-wear agents, acid scavengers, metal deactivators, and anti-foaming agents, wherein the amount of the composite stabilizer is at least 1%.

10. A fluid composition for a refrigerator, characterized in that: The invention comprises a refrigerant and the refrigerating machine oil according to claim 8 or 9.

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