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 is selected from alkoxy and aromatic hydrocarbon. The chemical composite stabilizer composition provided by the invention comprises the phenolic ester compound and the epoxy compound with specific structures, and the phenolic ester compound and the epoxy compound are synergistically applied to the refrigerating machine oil, so that excellent anti-oxidation and anti-hydrolysis stability can be shown; the stability performance of the working fluid for the refrigerating machine is improved; and the reliability 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; and refrigeration oil and refrigerant are used together in the refrigeration system. The type and component structure of the refrigeration oil should be changed and adjusted accordingly according to the changes in the refrigerant, so that the refrigeration oil composition has excellent compatibility, lubricity and stability to meet the requirements of the refrigeration system. Summary of the invention

[0003] 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 can improve the anti-oxidation and anti-hydrolysis stability of refrigeration oil.

[0004] 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.

[0005] 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;

[0006]

[0007] 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 is selected from alkoxy and aromatic hydrocarbon.

[0008] 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.

[0009] Optionally, in the structural compound represented by Formula 2, R6 is selected from C1 to C15 alkoxy groups.

[0010] 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 1:2 to 2:3.

[0011] Further optionally, the structural compound represented by Formula 1 comprises any one or more of the following compounds:

[0012]

[0013] Further optionally, the structural compound represented by Formula 2 comprises any one or more of the following compounds:

[0014]

[0015] As a second aspect of the present application, a method for preparing the composite stabilizer is provided, comprising:

[0016] 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;

[0017] Alkyl alcohol or aromatic hydrocarbon alcohol is reacted with epichlorohydrin in the presence of sodium hydroxide to generate a compound of structure shown in formula 2;

[0018] 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.

[0019] 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.

[0020] 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, metal deactivators, and anti-foaming agents.

[0021] 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.

[0022] The present application provides a chemical composite stabilizer composition, which comprises a phenolic ester compound and an epoxy compound of a specific structure. The synergistic use of the two compounds in refrigeration oil can exhibit excellent antioxidant and hydrolysis stability, thereby improving the stability of the working fluid for the refrigerator and the reliability life cycle of the refrigeration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] Figure 1-Figure 5Shown are the infrared spectra of Formula 1-1, Formula 1-2, Formula 1-3, Formula 2-1, and Formula 2-2, respectively. DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] At present, antioxidant BHT and acid scavenger E-10P are usually added to refrigeration oil to play the role of anti-oxidation and anti-hydrolysis, but the refrigeration oil added with the two reagents still has certain defects in performance indicators such as acid value, oxidation induction period, chromaticity, metal rod appearance, acid radical ions, etc., and has poor stability. 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

[0028] The 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 is selected from alkoxy and aromatic hydrocarbon.

[0031] The antioxidant in the present application is a high molecular weight phenolic ester antioxidant with a 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 free radical of the H atom and reacts with other free radicals to achieve the effect of consuming alkyl free radicals and peroxide free radicals. The acid scavenger in the present application is an epoxy compound with a structure shown in Formula 2. It can efficiently capture the acid radical ions generated during the operation of the refrigeration oil, and can also effectively terminate the generation of acid radical ions in coordination with the compound with the structure 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 is selected from C1-C15 alkoxy groups; in other embodiments of the present application, R6 is selected from C1-C15 straight-chain alkoxy groups, such as methoxy, ethoxy, heptoxy, octoxy, etc.

[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 1:2 to 2:3, for example 1:2, 3:5, 2:3, etc.; when the ratio is lower than the said range, the structural compound represented by Formula 2 accounts for a large proportion, the acid capture ability is strong, but the antioxidant ability is poor, and when it 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 the acid capture ability is poor. In the range of 1:2-2:3, the best antioxidant / acid capture ability can be achieved.

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

[0038]

[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] Alkyl alcohol or aromatic hydrocarbon alcohol is reacted with epichlorohydrin in the presence of sodium hydroxide 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 alkyl alcohol and aromatic hydrocarbon alcohol are determined according to the alkoxy group and aromatic hydrocarbon group selected by R6. For example, if n-heptyl alcohol and n-octanol are used as the reaction raw materials, R6 correspondingly selects C7H 15 O-alkoxy and C8H 17 O-.

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

[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] Alkyl alcohol or aromatic hydrocarbon alcohol reacts with epichlorohydrin under the catalysis of sodium hydroxide at 60-90°C. After the reaction is completed, the aqueous phase is extracted with dichloromethane and then the organic phases are combined and the solvent is removed by distillation under reduced pressure to generate a compound with the structure shown in formula 2.

[0051] 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.

[0052] 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, metal deactivators, and anti-foaming agents.

[0053] When the refrigeration oil is prepared, the total amount of base oil, composite stabilizer, anti-wear agent and metal deactivator is 100%, and the anti-foaming agent is additionally added on this basis.

[0054] In certain embodiments of the present application, the dosage of the composite stabilizer is at least 2%, and the optimal dosage is 2% to 5%. If the dosage is too low, the antioxidant and acid-trapping 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.

[0055] 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.

[0056] 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%;

[0057] 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%;

[0058] In certain embodiments of the present application, the antifoaming agent is selected from one or more of silicon-based antifoaming agents and non-silicon-based antifoaming agents. The silicon-based antifoaming agent may be dimethyl silicone oil; the non-silicon-based 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 may be 10 ppm to 100 ppm based on the total amount of the refrigeration oil and the antifoaming agent.

[0059] 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.

[0060] In certain embodiments of the present application, the refrigerant is selected from one or more saturated fluorocarbon (HFC) refrigerants, for example, preferably C1-C3 saturated fluorocarbons, more preferably C1-C2 saturated fluorocarbons. The refrigerant includes but is not limited to one or more of difluoromethane (R32), trifluoromethane (R23), pentafluoroethane (R125), 1,1,2,2-tetrafluoroethane (R134) and 1,1,1,2-tetrafluoroethane (R134a), which can be a single refrigerant or a mixed refrigerant. The content of refrigeration oil in the working fluid composition is not particularly limited. Relative to 100 parts by mass of refrigerant, it is preferred to use 1 to 500 parts by mass of refrigeration oil, and more preferably 2 to 400 parts by mass of refrigeration oil.

[0061] 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.

[0062] 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.

[0063] Example 1: Preparation of an exemplary compound of the structure shown in Formula 1

[0064] (1) Preparation of compound of formula 1-1

[0065] 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 .

[0066]

[0067] (2) Preparation of compound of formula 1-2

[0068] 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 .

[0069]

[0070] (3) Preparation of compound of formula 1-3

[0071] 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 .

[0072]

[0073] Example 2: Preparation of an exemplary compound of the structure compound represented by Formula 2

[0074] (1) Preparation of compound of formula 2-1

[0075] n-Heptanol and epichlorohydrin react with 0.1 mol / L sodium hydroxide as a catalyst, at a temperature of about 60 to 90°C, and stirred for 4 to 6 hours for a chemical reaction. After the reaction is completed, the mixture is separated, the aqueous phase is extracted with dichloromethane, the organic phases are combined and the solvent is removed by vacuum distillation to obtain a transparent liquid, which is the compound of formula 2-1. The infrared spectrum is shown in Figure 4 .

[0076]

[0077] (2) Preparation of compound of formula 2-2

[0078] n-Octanol and epichlorohydrin react with 0.1 mol / L sodium hydroxide as a catalyst, at a temperature of about 60 to 90°C, and stirred for 4 to 6 hours for a chemical reaction. After the reaction is completed, the mixture is separated, the aqueous phase is extracted with dichloromethane, the organic phases after extraction are combined, and the solvent is removed by vacuum distillation to obtain a transparent liquid, which is the compound of formula 2-2. The infrared spectrum is shown in Figure 5 .

[0079]

[0080] Example 3: Example composite stabilizer

[0081] 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;

[0082] Table 1

[0083] serial number name Compound of formula 1 Compound of formula 2 Mass ratio 1 Composite stabilizer A1 Formula 1-1 Formula 2-1 1 serving: 2 servings 2 Composite stabilizer A2 Formula 1-2 Formula 2-1 3 servings: 5 servings 3 Composite stabilizer A3 Formula 1-2 Formula 2-2 2 servings: 3 servings 4 Composite stabilizer A4 Formula 1-3 Formula 2-1 1 serving: 2 servings 5 Composite stabilizer A5 Formula 1-1 Formula 2-1 2 servings: 3 servings 6 Composite stabilizer A6 Formula 1-3 Formula 2-1 3 servings: 5 servings 7 Composite stabilizer A7 Formula 1-2 Formula 2-1 2 servings: 3 servings 8 Composite stabilizer A8 Formula 1-1 Formula 2-1 3 servings: 5 servings 9 Composite stabilizer A9 Formula 1-2 Formula 2-1 1 serving: 2 servings 10 Composite stabilizer A10 Formula 1-1 Formula 2-2 1 serving: 2 servings 11 Composite stabilizer A11 Formula 1-2 Formula 2-2 1 serving: 2 servings 12 Composite stabilizer A12 Formula 1-1 Formula 2-2 2 servings: 3 servings 13 Composite stabilizer A13 Formula 1-3 Formula 2-2 1 serving: 2 servings 14 Composite stabilizer A14 Formula 1-2 Formula 2-2 3 servings: 5 servings 15 Composite stabilizer A15 Formula 1-1 Formula 2-2 3 servings: 5 servings 16 Composite stabilizer A16 Formula 1-3 Formula 2-1 2 servings: 3 servings 17 Composite stabilizer A17 Formula 1-3 Formula 2-2 2 servings: 3 servings 18 Composite stabilizer A18 Formula 1-3 Formula 2-2 3 servings: 5 servings

[0084] Experimental example:

[0085] (1) Kinematic viscosity measurement

[0086] According to ASTM D 445-2009, the kinematic viscosity of petroleum products was measured at 40°C and 100°C for refrigeration oil.

[0087] (2) Stability test

[0088] 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 R32), 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.

[0089] (3) Chromaticity test

[0090] 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.

[0091] (4) Acid ion test

[0092] 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.

[0093] (5) Oxidation stability test

[0094] 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.

[0095] (6) Refrigerating machine oil and refrigerating machine working fluid composition

[0096] ① Experimental group of this application:

[0097] The raw material alcohol in the base oil is pentaerythritol and neopentyl glycol, the organic acid is maleic anhydride, n-butyric acid and isononanoic acid, and the base oil is synthetic ester POE oil;

[0098] The additives in refrigeration oil are as follows:

[0099] Additive A: composite stabilizer of Table 1;

[0100] Additive B: antifoaming agent 2-methylsilane;

[0101] Additive C: metal deactivator Irgamet 39;

[0102] Additive D: anti-wear agent T306;

[0103] The refrigerant is R32.

[0104] ②Control group:

[0105] The raw material alcohol in the base oil is pentaerythritol and neopentyl glycol, the organic acid is maleic anhydride, n-butyric acid and isononanoic acid, and the base oil is synthetic ester POE oil;

[0106] The additives in refrigeration oil are as follows:

[0107] Antioxidant additive: BHT;

[0108] Acid capture additive: E-10P;

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

[0110] Additive C: metal deactivator Irgamet 39;

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

[0112] The refrigerant is R32.

[0113] Table 2 Experimental groups 1-6 and their performance parameters

[0114]

[0115] Table 3 Control groups 1-8 and their performance parameters

[0116]

[0117] 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 added with conventional antioxidant BHT and / or acid scavenger E-10P, both of which have similar effects to the compounds of Formula 1 and Formula 2 of the present application, but are obviously inferior to the experimental group added with the composite stabilizer of the present application in terms of various indicators:

[0118] Among them, the appearance of the metal rods of the control groups 1-3 were all grade 2a, while the grades of the experimental groups were all grade 1; the acid values ​​of the control groups 1-3 were 0.15-0.2 mgKOH / g, while the acid values ​​of the experimental groups were all below 0.1 mgKOH / g; the oxidation induction period of the control groups 1-3 was generally around 20 minutes, while the oxidation induction period of the experimental groups was almost all above 30 minutes, and the highest could reach 38 minutes; the chromaticity values ​​of the control groups 1-3 were 3.0-3.5, while the chromaticity values ​​of the experimental groups were 1.0-1.5; the acid radical ions of the control groups 1-3 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, and have a more excellent effect than the conventional composite of similar functional substances.

[0119] Control group 4, control group 5, control group 7 and control group 8 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 it is the control group 4 with a ratio of the two compounds lower than 1:2 to 2:3 of the present application, or the control group 5 with a ratio higher than 1:2 to 2:3 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 7 is less than 2%, and the antioxidant and acid-trapping effects are not obvious due to the low addition amount. The total dosage of control group 8 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.

[0120] The scheme of control group 6 is to not add any antioxidants and acid scavengers. According to its various indicators, its antioxidant and anti-hydrolysis stability are the worst among all the schemes.

[0121] The comparison of the above schemes shows that adding the composite stabilizer of the present application can improve the anti-oxidation and anti-hydrolysis stability of refrigeration oil, and its effect is better than the composite of similar substances.

[0122] 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; and R6 is selected from alkoxy and 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 is selected from C1-C15 alkoxy groups.

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 1:2 to 2:

3.

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; Alkyl alcohol or aromatic hydrocarbon alcohol is reacted with epichlorohydrin in the presence of sodium hydroxide 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, metal deactivators, and anti-foaming agents, wherein the amount of the composite stabilizer is at least 2%.

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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