Preparation method of alkoxy hindered amine stabilizer

Abstract

The invention provides a preparation method of an alkoxy hindered amine stabilizer, and relates to the technical field of preparation of light stabilizers. The alkoxy hindered amine stabilizer is prepared from a triazine compound containing sterically hindered amine, an oxidizing agent, a catalyst and a solvent, wherein the reaction is divided into a first stage with a lower temperature and a second stage with a higher temperature. Preferably, the oxidizing agent is halogenated isocyanuric acid, and the catalyst is a supported catalyst with crown ether coordinated with a molybdenum source. The preparation method provided by the invention can realize high conversion rate of the triazine compound and high selectivity of the alkoxy hindered amine stabilizer.

Description

Technical Field

[0001] This invention belongs to the field of light stabilizer preparation technology, and relates to a method for preparing an alkoxy-hindered amine stabilizer. Background Technology

[0002] Traditional light stabilizers contain NH groups on their rings, exhibiting a certain degree of alkalinity, which limits their application in acidic resins, acidic compounding agents, and acidic environments. Low-alkalinity hindered amine light stabilizers (HALS), especially N-alkoxy HALS, combine the functions of light stabilizers and halogen-free flame retardants, and are widely used in materials such as polyethylene (PE) and polypropylene (PP), achieving good results with relatively small addition amounts. Currently, there are numerous reports on the preparation techniques of N-alkoxy HALS. Chinese patent CN115785069A discloses a method for preparing the hindered amine flame retardant NOR116, which involves preparing an N-cyclohexyloxy hindered amine compound (compound of formula 3) from compound 1 (containing an NH group) in two steps; Chinese patent CN106699639A discloses a method for synthesizing the light stabilizer HS-112, which involves preparing bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate in two steps, first oxidizing the NH group to a nitroxide radical, and then introducing an octyl group onto the nitroxide radical by oxidation; Chinese patent CN113354813A discloses a method for preparing the low-alkalinity hindered amine light stabilizer NOR371, which involves three steps: the first step is the oxidation of the NH group to a nitroxide radical, the second step is the conversion of the nitroxide radical to N-OH, and the third step is the conversion of the hydroxyl group to a propoxy group. The preparation of N-alkoxy HALS requires two or three steps, which is a long process and the yield of each step is not high enough, which will affect the yield of the final product.

[0003] Chinese patent CN110862342A discloses a method for preparing bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate. The method uses hindered amine light stabilizer 770 and octane as raw materials, and obtains the product through a one-step reaction in the presence of an oxidant and a supported molybdenum catalyst. The yield is approximately 94-98%, the purity is approximately 95%, the color is low, and there is no peroxide residue. Commercially available light stabilizers generally require a purity of 99% or higher; therefore, the purity of the product obtained by the above method is insufficient and further purification is necessary.

[0004] Therefore, the applicant believes that the existing preparation techniques for N-alkoxy HALS need further optimization and improvement. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for preparing an alkoxy-hindered amine stabilizer.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing an alkoxy-hindered amine stabilizer, wherein the alkoxy-hindered amine stabilizer has the structure shown in formula (1).

[0008]

[0009] Wherein, R1 is selected from C1-C24 alkyl, and R2 is selected from C5-C10 alkyl or C5-C7 cycloalkyl;

[0010] The preparation method is as follows: the raw material components containing the triazine compound, oxidant, catalyst and solvent R2H shown in formula (2) are reacted in a reaction vessel to obtain the alkoxy hindered amine stabilizer;

[0011]

[0012] The reaction consists of two stages. The reaction temperature of the first stage is 50-80℃, and the reaction temperature of the second stage is 1-5℃ lower than T1.

[0013] T1 is the boiling point of the solvent R2H at 1 standard atmosphere.

[0014] Preferably, the reaction temperature of the first stage is 60-70℃.

[0015] Preferably, the reaction time of the first stage is 1-3 hours, and the reaction time of the second stage is 2-3 hours.

[0016] Preferably, the oxidant is selected from one or a combination of two or more of hydrogen peroxide, peracetic acid, tert-butyl hydrogen peroxide, hypochlorous acid, and haloisocyanuric acid.

[0017] More preferably, the oxidant is selected from haloisocyanuric acid.

[0018] Preferably, the catalyst is composed of a porous support and an active ingredient;

[0019] The active ingredient is a complex of a molybdenum source and a crown ether.

[0020] More preferably, the catalyst is prepared by adding the molybdenum source, the crown ether, and the porous support into an organic solvent, stirring the reaction for a certain time, collecting the solid, washing and drying it to obtain the catalyst.

[0021] More preferably, the molar ratio of the molybdenum source to the crown ether is 1:0.5-3;

[0022] The weight ratio of the molybdenum source to the porous carrier is 1:1-10;

[0023] The molybdenum source is selected from one or a combination of two or more of molybdenum trioxide and molybdate.

[0024] The crown ether is selected from 18-crown-6 and / or 15-crown-5.

[0025] More preferably, the stirring reaction is a room temperature reaction under normal pressure or a hydrothermal reaction at 100-180°C.

[0026] Preferably, the molar ratio of the triazine compound, the oxidant, and the solvent R2H is 1:5-10:10-40;

[0027] The catalyst weighs 0.1-3% of the weight of the triazine compound.

[0028] The beneficial effects of this invention are:

[0029] (1) In the preparation of the alkoxy-hindered amine stabilizer, the present invention uses a two-stage reaction at different temperatures, which is beneficial to improving the conversion rate of the triazine compound and the selectivity of the product - the alkoxy-hindered amine stabilizer shown in formula (1).

[0030] (2) The preferred oxidant of the present invention is haloisocyanuric acid, which has strong oxidizing power and good controllability. It is beneficial to the full oxidation of triazine compounds and solvents, while avoiding excessive oxidation. It has a good oxidation effect and is conducive to improving the conversion rate of triazine compounds and the selectivity of products.

[0031] (3) The active component of the catalyst of the present invention is preferably a complex of molybdenum source and crown ether. Crown ether, as a ligand of molybdenum source, improves the catalytic activity of molybdenum source and can further improve the conversion rate of triazine compound and the selectivity of product. Detailed Implementation

[0032] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0033] This invention proposes a method for preparing an alkoxy-hindered amine stabilizer, which has the structure shown in formula (1).

[0034]

[0035] Wherein, R1 is selected from C1-C24 alkyl, and R2 is selected from C5-C10 alkyl or C5-C7 cycloalkyl;

[0036] The preparation method is as follows: the raw material components containing the triazine compound shown in formula (2), oxidant, catalyst and solvent R2H are reacted in a reaction vessel to obtain alkoxy hindered amine stabilizer;

[0037]

[0038] The reaction consists of two stages. The first stage reaction temperature is 50-80℃, and the second stage reaction temperature is 1-5℃ lower than T1.

[0039] T1 is the boiling point of solvent R2H at 1 standard atmosphere.

[0040] The alkoxyhedral amine stabilizer of the present invention has a triazine intermediate structure with three 2,2,6,6-tetramethylpiperidine structures attached to an amino group. There is an R2O substituent at the 1 position of the piperidine, which makes the structure more symmetrical and has lower basicity. The R1 group can improve stability, flexibility and compatibility with polyolefins, etc.

[0041] The preparation method of this invention mainly involves three reactions: reaction ①, the oxidation reaction of NH groups by the oxidant; reaction ②, the partial oxidation reaction of solvent R2H by the oxidant; and reaction ③, the reaction between the oxidized R2H and the oxidized NH groups. The oxidation reactions of NH groups and solvent R2H have different reactivity; the oxidation reaction of solvent R2H is more difficult to occur than the oxidation reaction of NH groups. The preparation method of this invention divides the reaction into two stages. The first stage has a lower reaction temperature, which is conducive to the occurrence of reaction ①. The second stage has a higher reaction temperature, close to the boiling point of solvent R2H, increasing the reactivity of solvent R2H and thus favoring the occurrence of reactions ② and ③. This avoids the over-oxidation reaction in reaction ①, which could affect the reaction process or generate unnecessary impurities.

[0042] Taking n-octane as an example, where n-octane serves as both a solvent and a reactant, and its boiling point at 1 atmosphere is 126°C, the reaction temperature for the second stage of the above reaction could be 121°C, 122°C, 123°C, 124°C, 125°C, etc. Similarly, taking cyclohexane as an example, where it serves as both a solvent and a reactant, and its boiling point at 1 atmosphere is 81°C, the reaction temperature for the second stage of the above reaction could be 76°C, 77°C, 78°C, 79°C, 80°C, etc.

[0043] The triazine compound shown in formula (2) above can be prepared by the reaction shown in formula (3).

[0044]

[0045] In this reaction, compound A is cyanuric chloride, and compound B can be N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, N-hexyl-2,2,6,6-tetramethyl-4-piperidinamine, N-octyl-2,2,6,6-tetramethyl-4-piperidinamine, N-cyclohexyl-2,2,6,6-tetramethyl-4-piperidinamine, etc., all of which can be obtained directly from the market. For the reaction shown in the above formula (3), the reaction can be carried out at 50-100℃. A basic compound (such as triethylamine, sodium carbonate, potassium carbonate, etc.) is used as an acid-binding agent to absorb the generated hydrogen chloride and promote the reaction towards the product. An appropriate excess of compound B can promote the complete reaction of compound A.

[0046] For the alkoxy-hindered amine stabilizer shown in formula (1) of the present invention, when R1 is butyl and R2 is octyl, it can be named 2,4,6-tris[(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)butylamino]-1,3,5-triazine; when R1 is propyl and R2 is cyclohexyl, it can be named 2,4,6-tris[(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)propylamino]-1,3,5-triazine.

[0047] In some embodiments, the reaction temperature of the first stage is 60-70°C, which is conducive to the progress of the above reaction ①, namely the oxidation reaction of solvent R2H. For example, the reaction temperature of the first stage can be 60°C, 62°C, 65°C, 68°C, 70°C, etc.

[0048] In some embodiments, the reaction time for the first stage is 1-3 hours, and the reaction time for the second stage is 2-3 hours. Since the reaction temperature in the second stage is higher, and the second stage is responsible for completing reactions ② and ③ above, if the reaction time is too long, it may lead to excessive impurity formation or over-oxidation of the solvent R2H, which is detrimental to improving the purity of the final product.

[0049] In some embodiments, the oxidant is selected from one or a combination of two or more of hydrogen peroxide, peracetic acid, tert-butyl hydroperoxide, hypochlorous acid, and haloisocyanuric acid. The oxidant can be added in the form of an aqueous solution, such as hydrogen peroxide, 50-70 wt% tert-butyl hydroperoxide, or 40-60 wt% haloisocyanuric acid. For oxidants such as hydrogen peroxide and tert-butyl hydroperoxide, if all the oxidant is added at the beginning, the concentration will be too high in the early stages and too low in the later stages, resulting in an uneven oxidation reaction process, such as over-oxidation in the early stages and under-oxidation in the later stages. Therefore, the oxidant is generally added dropwise or in batches.

[0050] Furthermore, the oxidant is selected from haloisocyanuric acid. Haloisocyanuric acid has strong oxidizing power and high controllability of oxidation, which is conducive to the full oxidation of triazine compounds and solvents while avoiding over-oxidation. It has a good oxidation effect, which is beneficial to improving the conversion rate of triazine compounds and the selectivity of products, and reducing the formation of impurities. Moreover, there is no need to use the method of dropwise addition or batch addition. It can be added directly at the beginning of the reaction, which optimizes the process. For example, the haloisocyanuric acid can be dichloroisocyanuric acid, trichloroisocyanuric acid, chlorobromoisocyanuric acid, etc., and is added in the form of an aqueous solution. In addition, in this invention, the reaction temperature of the preparation method is significantly different depending on the solvent R2H used and its boiling point. For example, when the solvent R2H is n-octane and cyclohexane, the reaction temperature of the second stage will differ by about 40°C. It is required that the oxidant has a suitable oxidation effect over a wide temperature range. Haloisocyanuric acid meets this requirement and can provide a continuous and stable oxidation effect.

[0051] In some embodiments, the catalyst consists of a porous support and an active component;

[0052] The active ingredient is a complex of molybdenum source and crown ether.

[0053] Furthermore, the catalyst is prepared by adding a molybdenum source, crown ether, and porous support to an organic solvent, stirring the reaction for a certain time, collecting the solid, washing and drying it to obtain the catalyst.

[0054] This invention discovers that using crown ethers as ligands for the molybdenum source can enhance the catalytic activity of the molybdenum source, further improving the reaction rate, the conversion rate of triazine compounds, and / or the selectivity of the products, while reducing the formation of impurities. This may be related to the fact that the added oxidant is an aqueous solution, and the solvent R₂H is immiscible with water, resulting in two immiscible phases—an aqueous phase and an oil phase—existing in the reaction solution. Crown ethers act as phase transfer promoters, compensating for or offsetting the adverse effects of water on the molybdenum source as a catalyst. Using a porous support is beneficial for both the dispersion of active components and the recovery and reuse of the catalyst, improving the economics of the method. There are no particular limitations on the porous support; for example, it can be zeolite, mesoporous silica, activated carbon, copper foam, nickel foam, porous alumina, etc.

[0055] Furthermore, the molar ratio of the molybdenum source to the crown ether is 1:0.5-3; for example, the molar ratio of the molybdenum source to the crown ether can be any value or any value in between such as 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc., without any particular restriction; further still, the molar ratio of the molybdenum source to the crown ether can be 1:0.5-2.

[0056] The weight ratio of the molybdenum source to the porous support is 1:1-10; for example, the weight ratio of the molybdenum source to the porous support can be any value or any value between 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc., without any particular restriction; furthermore, the weight ratio of the molybdenum source to the porous support can be 1:2-7.

[0057] The molybdenum source is selected from one or more combinations of molybdenum trioxide and molybdate; for example, molybdate can be sodium molybdate, potassium molybdate, magnesium molybdate, etc.

[0058] The crown ether is selected from 18-crown-6 and / or 15-crown-5.

[0059] Furthermore, the stirring reaction is either a room temperature reaction under normal pressure or a hydrothermal reaction at 100-180℃. The hydrothermal reaction is more conducive to the formation of ligands with strong binding force between the molybdenum source and the crown ether, thereby improving the coordination effect of the crown ether on the molybdenum source.

[0060] In some embodiments, the molar ratio of the triazine compound, the oxidant, and the solvent R2H is 1:5-10:10-40; for example, the molar ratio of the triazine compound, the oxidant, and the solvent R2H can be any value or any value between 1:5:10, 1:5:20, 1:5:30, 1:5:40, 1:7:10, 1:7:20, 1:7:30, 1:7:40, 1:10:10, 1:10:20, 1:10:30, 1:10:40, etc., without any particular limitation;

[0061] The catalyst weight is 0.1-3% of the weight of the triazine compound. For example, the catalyst weight can be any value or any value between 0.5%, 1%, 1.5%, 2%, 2.5%, and 3% of the weight of the triazine compound, without particular limitation. When the catalyst is an unsupported catalyst, the catalyst weight can be 0.1-0.5% of the weight of the triazine compound; when the catalyst is a supported catalyst, the weight percentage needs to be increased, and the catalyst weight can be 1-3% of the weight of the triazine compound.

[0062] The technical solution of the present invention will be further described and explained below based on various preparation examples and embodiments.

[0063] Preparation Examples 1-3: Preparation of Triazine Compounds

[0064] Preparation Example 1

[0065] 0.1 mol cyanuric chloride, 100 ml butyl acetate, and 0.31 mol triethylamine were added to a reaction vessel. After dissolution, the temperature was controlled to not exceed 10 °C. A mixed solution of 0.303 mol N-butyl-2,2,6,6-tetramethyl-4-piperidinamine and 20 ml butyl acetate was added dropwise. After the addition was complete, the reaction continued for 6 h. The temperature was then raised to 50 °C and the reaction continued for 12 h. The temperature was then raised to 90 °C and the reaction continued for 12 h. High performance liquid chromatography showed that the cyanuric chloride was completely converted. The mixture was cooled to room temperature, filtered, and the organic solvent was removed from the filtrate to obtain the product, denoted as triazine compound A.

[0066] Preparation Example 2

[0067] 0.1 mol cyanuric chloride, 100 ml butyl acetate, and 0.31 mol triethylamine were added to a reaction vessel. After dissolution, the temperature was controlled to not exceed 10 °C. A mixed solution of 0.303 mol N-propyl-2,2,6,6-tetramethyl-4-piperidinamine and 20 ml butyl acetate was added dropwise. After the addition was complete, the reaction continued for 6 h. The temperature was then raised to 50 °C and the reaction continued for 12 h. The temperature was then raised to 90 °C and the reaction continued for 10 h. High performance liquid chromatography showed that the cyanuric chloride was completely converted. The mixture was cooled to room temperature, filtered, and the organic solvent was removed from the filtrate to obtain the product, which was denoted as triazine compound B.

[0068] Preparation Example 3

[0069] 0.1 mol cyanuric chloride, 100 ml butyl acetate, and 0.31 mol triethylamine were added to a reaction vessel. After dissolution, the temperature was controlled to not exceed 10 °C. A mixed solution of 0.303 mol N-octyl-2,2,6,6-tetramethyl-4-piperidinamine and 20 ml butyl acetate was added dropwise. After the addition was complete, the reaction was continued for 12 h. The temperature was then raised to 50 °C and the reaction was continued for another 12 h. The temperature was then raised to 90 °C and the reaction was continued for another 16 h. High performance liquid chromatography showed that the cyanuric chloride was completely converted. The mixture was cooled to room temperature, filtered, and the organic solvent was removed from the filtrate to obtain the product, denoted as triazine compound C.

[0070] Example 1

[0071] 0.1 mol of triazine compound A from Preparation Example 1, 70% aqueous solution of tert-butyl hydrogen peroxide (0.5 mol of tert-butyl hydrogen peroxide), 3 mol of n-octane, and nano-sized molybdenum trioxide (0.2% of the weight of triazine compound A) were added to a reaction vessel. The mixture was heated to 70°C under normal pressure and kept at that temperature for 2 h. Then, the temperature was rapidly increased to 122°C and kept at that temperature for 2 h. Part of the n-octane was removed under reduced pressure and the mixture was concentrated. After filtration, the remaining low-boiling substances were removed from the filtrate to obtain the product.

[0072] Example 2

[0073] The difference between this embodiment and Example 1 is that in Example 1, the 70% tert-butyl hydrogen peroxide aqueous solution is replaced with a 60% trichloroisocyanuric acid aqueous solution (0.5 mol of trichloroisocyanuric acid). The remaining steps remain unchanged.

[0074] Example 3

[0075] The difference between this embodiment and Embodiment 2 is that in Embodiment 2, nano-sized molybdenum trioxide is replaced with a supported catalyst, and the weight of the supported catalyst is 1.2% of the weight of triazine compound A. The remaining steps remain unchanged.

[0076] The preparation method of the supported catalyst is as follows: 0.1 mol of nano-sized molybdenum trioxide, 0.1 mol of 18-crown-6 and 72 g of porous alumina from Example 1 were added to 500 ml of butyl acetate and stirred at room temperature for 12 h. The solid was collected and washed twice with ultrapure water, and then vacuum dried overnight in an oven at 60 °C to obtain the supported catalyst.

[0077] Example 4

[0078] The difference between this embodiment and Embodiment 2 is that in Embodiment 2, nano-sized molybdenum trioxide is replaced with a supported catalyst, and the weight of the supported catalyst is 1.2% of the weight of triazine compound A. The remaining steps remain unchanged.

[0079] The preparation method of the supported catalyst is as follows: 0.1 mol sodium molybdate, 0.1 mol 18-crown-6 and 103 g porous alumina are added to 700 ml of ultrapure water. The container is sealed and placed in a hydrothermal environment at 110 ℃ for 4 h. After cooling, the solid is collected and washed twice with ultrapure water. Then it is vacuum dried in an oven at 60 ℃ overnight to obtain the supported catalyst.

[0080] Comparative Example 1

[0081] 0.1 mol of triazine compound A from Preparation Example 1, 70% aqueous solution of tert-butyl hydrogen peroxide (0.5 mol of tert-butyl hydrogen peroxide), 3 mol of n-octane, and nano-sized molybdenum trioxide (0.2% of the weight of triazine compound A) were added to a reaction vessel. The mixture was heated to 70°C under normal pressure and kept at that temperature for 4 hours. The temperature was then reduced and heated to 90°C to remove some of the n-octane for concentration. The mixture was filtered, and the remaining low-boiling substances were removed from the filtrate to obtain the product.

[0082] Comparative Example 2

[0083] The difference between this comparative example and Comparative Example 1 is that in Comparative Example 1, the process of heating to 70°C under normal pressure and holding the reaction at that temperature for 4 hours was changed to heating to 122°C under normal pressure and holding the reaction at that temperature for 4 hours. The remaining steps remain unchanged.

[0084] Comparative Example 3

[0085] The difference between this comparative example and Comparative Example 1 is that in Comparative Example 1, the process of heating to 70°C under normal pressure and holding the reaction at that temperature for 4 hours is changed to heating to 100°C under normal pressure and holding the reaction at that temperature for 4 hours. The remaining steps remain unchanged.

[0086] Example 5

[0087] 0.1 mol of triazine compound B from Preparation Example 2, 70% aqueous solution of dichloroisocyanuric acid (0.8 mol of dichloroisocyanuric acid), 2 mol of cyclohexane, and sodium molybdate (sodium molybdate weight is 0.4% of the weight of triazine compound B) were added to a reaction vessel. The mixture was heated to 60°C under normal pressure and kept at that temperature for 3 hours. Then, the temperature was rapidly increased to 78°C and kept at that temperature for 3 hours. Part of the cyclohexane was removed under reduced pressure and the mixture was concentrated. After filtration, the remaining low-boiling substances were removed from the filtrate to obtain the product.

[0088] Example 6

[0089] The difference between this embodiment and Embodiment 5 is that in Embodiment 5, the 70% dichloroisocyanuric acid aqueous solution is replaced with 70% hydrogen peroxide (0.8 mol of hydrogen peroxide), and the hydrogen peroxide is added dropwise over 1 hour. The remaining steps remain unchanged.

[0090] Example 7

[0091] The difference between this embodiment and Example 5 is that in Example 5, the sodium molybdate catalyst was replaced with a supported catalyst, and the weight of the supported catalyst was 1.5% of the weight of triazine compound B. The remaining steps remained unchanged.

[0092] The preparation method of the supported catalyst is as follows: 0.1 mol sodium molybdate, 0.15 mol 18-crown-6 and 100 g porous alumina are added to 1000 ml of ultrapure water. The container is sealed and placed in a hydrothermal reaction environment at 120 ℃ for 4 h. After cooling, the solid is collected and washed twice with ultrapure water. Then it is vacuum dried in an oven at 60 ℃ overnight to obtain the supported catalyst.

[0093] Comparative Example 4

[0094] The difference between this comparative example and Example 7 is that in Example 7, 18-crown-6 was replaced with an equimolar amount of EDTA-Na. The remaining steps remained unchanged.

[0095] Example 8

[0096] The difference between this embodiment and Example 7 is that in Example 7, triazine compound B is replaced with an equimolar amount of triazine compound C from Preparation Example 3. All other steps remain unchanged.

[0097] The conversion rates, product selectivity, and actual product yields of the triazine compounds in Examples 1-8 and Comparative Examples 1-4 are shown in Table 1 below.

[0098] Actual product yield = triazine compound conversion × product selectivity

[0099] Table 1

[0100]

[0101] Therefore, the results above show that the reaction using a combination of low and high temperatures is more favorable for the conversion of triazine compounds and the selectivity of the products; the oxidation effect of haloisocyanuric acid is better than that of hydrogen peroxide and tert-butyl hydrogen peroxide; crown ether as a molybdenum source catalyst improves the catalytic effect and is beneficial to the conversion of triazine compounds and the selectivity of the products.

[0102] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an alkoxy-hindered amine stabilizer, characterized in that, The alkoxy-hindered amine stabilizer has the structure shown in formula (1). Wherein, R1 is selected from C1-C24 alkyl, and R2 is selected from C5-C10 alkyl or C5-C7 cycloalkyl; The preparation method is as follows: the raw material components containing the triazine compound, oxidant, catalyst and solvent R2H shown in formula (2) are reacted in a reaction vessel to obtain the alkoxy hindered amine stabilizer; The reaction consists of two stages. The reaction temperature of the first stage is 50-80℃, and the reaction temperature of the second stage is 1-5℃ lower than T1. T1 is the boiling point of the solvent R2H at 1 standard atmosphere.

2. The method for preparing the alkoxy-hindered amine stabilizer according to claim 1, characterized in that, The reaction temperature in the first stage is 60-70℃.

3. The method for preparing the alkoxy-hindered amine stabilizer according to claim 1, characterized in that, The reaction time for the first stage is 1-3 hours, and the reaction time for the second stage is 2-3 hours.

4. The method for preparing the alkoxy-hindered amine stabilizer according to claim 1, characterized in that, The oxidant is selected from one or a combination of two or more of hydrogen peroxide, peracetic acid, tert-butyl hydrogen peroxide, hypochlorous acid, and haloisocyanuric acid.

5. The method for preparing the alkoxy-hindered amine stabilizer according to claim 4, characterized in that, The oxidant is selected from haloisocyanuric acid.

6. The method for preparing the alkoxy-hindered amine stabilizer according to claim 1, characterized in that, The catalyst is composed of a porous support and an active ingredient; The active ingredient is a complex of a molybdenum source and a crown ether.

7. The method for preparing the alkoxy-hindered amine stabilizer according to claim 6, characterized in that, The catalyst is prepared by adding the molybdenum source, the crown ether, and the porous support into an organic solvent, stirring the reaction for a certain time, collecting the solid, washing and drying it to obtain the catalyst.

8. The method for preparing the alkoxy-hindered amine stabilizer according to claim 7, characterized in that, The molar ratio of the molybdenum source to the crown ether is 1:0.5-3; The weight ratio of the molybdenum source to the porous carrier is 1:1-10; The molybdenum source is selected from one or a combination of two or more of molybdenum trioxide and molybdate. The crown ether is selected from 18-crown-6 and / or 15-crown-5.

9. The method for preparing the alkoxy-hindered amine stabilizer according to claim 7, characterized in that, The stirring reaction is a room temperature reaction under normal pressure or a hydrothermal reaction at 100-180℃.

10. The method for preparing the alkoxy-hindered amine stabilizer according to claim 1, characterized in that, The molar ratio of the triazine compound, the oxidant, and the solvent R2H is 1:5-10:10-40; The catalyst weighs 0.1-3% of the weight of the triazine compound.

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