An antioxidant with light stability and anti-thermal oxidative aging ability and a preparation method thereof

Abstract

The application discloses an antioxidant with light stability and heat-oxidation aging resistance and a preparation method thereof. The product contains a hindered phenol and a hindered amine structure, and simultaneously has an amide structure, so that the product has excellent compatibility in polyamide and can effectively improve the anti-aging performance of the polyamide.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic synthesis, and relates to a synthesis process of an antioxidant, and particularly relates to a synthesis method of 6-amino-N-(2,2,6,6-tetramethyl-4-piperidyl)-(ethyl-dodecyl) amide and 4-hydroxy-alpha,alpha-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidyl) amino] ethyl-dodecyl] benzamide compounds. BACKGROUND

[0002] As one of the five general-purpose engineering plastics, polyamide has a wide application in many fields, such as medical devices, electronics and electrical appliances, automobiles, machinery, textiles and the like. The polyamide raw material generally presents an opaque light white color, and after oxidation, it usually presents yellow, orange and severe reddish brown, which not only causes the appearance of the material to be poor, but also causes the performance of the material to be sharply attenuated. The addition of an antioxidant can effectively prolong the oxidation period of the polyamide material and reduce the performance loss of the polyamide material. Many companies including BASF, Dow and the like have developed antioxidants for polyamide, and there are polyamide heat-oxidation-resistant agents such as 1098, 1010 and 1076, and light stabilizers such as 445, 622 and 770, but there are few antioxidants with both heat-oxidation resistance and light stability.

[0003] He Liming, Zeng Jia and the like provide a bisphenol compound synthesized from 2,6-di-tert-butyl-phenol as a hindered phenol raw material, which needs to add various dehydrating agents, and the final efficiency is not higher than 70%. The steps are relatively complicated. At the same time, there are many types of organic solvents and other reaction participants, and the steps are complicated.

[0004] Liu Junli, Zhao Hingjiang and the like provide three synthesis methods of novel structural hindered phenol type antioxidants based on 3,5-di-tert-butyl-4-hydroxy-benzenepropanoic acid, which synthesize various monophenol, bisphenol and polyphenol antioxidants through organic solvents and aluminum isopropyl alcohol, and the overall method is relatively simple, but the method involves metal elements, which can cause the appearance of metal ion complexes and induce the intensification of oxidation reaction. The method only describes the synthesis of the antioxidant, and does not evaluate and compare the antioxidant capacity.

[0005] Li Keguo, Zhang Huijing and the like provide a synthesis method of a hindered amine light stabilizer containing a hindered phenol structure, which carries out the reaction by adding a supported catalyst MF / γ-Al2O3 and a supported tin tetrachloride catalyst. Compared with the previous synthesis route, the method has a good simplification, but the catalyst synthesized is prone to failure, the reaction temperature is relatively high, and a plurality of organic reagents are involved. SUMMARY

[0006] The present application aims at the current situation that no antioxidant has both light stability and anti-thermal oxidation stability, and provides a kind of 4-hydroxy-alpha, alpha-dimethyl-N-[6-[(2, 2, 6, 6-tetramethyl-4-piperidyl) amino] ethyl-dodecyl] benzamide compound and a synthesis method thereof, which has simple method, high yield, mild reaction condition and simple steps.

[0007] In one aspect, the present application provides an antioxidant with light stability and anti-thermal oxidation stability, which has the following structure:

[0008] Wherein n is an integer of 1-11, and R is independently selected from groups with electron-donating effect, such as methyl, disubstituted methyl, isobutyl, tert-butyl, preferably a tert-butyl group.

[0009] In another aspect, the present application also provides a preparation method of the antioxidant, which synthesis route comprises:

[0010] (1) acyl chloride reaction:

[0011]

[0012] (2) amide reaction of 4-amino-2, 2, 6, 6-tetramethylpiperidine:

[0013]

[0014] (3) synthesis reaction of 4-hydroxy-alpha, alpha-dimethyl-N-[6-[(2, 2, 6, 6-tetramethyl-4-piperidyl) amino] ethyl-dodecyl] benzamide compound:

[0015]

[0016] In the present application, the preparation method comprises the following steps: (1) synthesis of w-amino acyl chloride and p-hydroxybenzoyl chloride compound; (2) synthesis of 6-amino-N-(2, 2, 6, 6-tetramethyl-4-piperidyl)-(ethyl-dodecyl) amide; (3) synthesis of antioxidant.

[0017] Wherein:

[0018] The w-amino acid has the following structure Wherein n is the number of carbon atoms 1-11;

[0019] The w-amino acyl chloride has the following structure:

[0020] Wherein n is the number of carbon atoms 1-11;

[0021] The p-hydroxybenzoic acid compound has the following structure: wherein R is independently selected from groups having electron donating effect, such as methyl, disubstituted methyl, isobutyl, tert-butyl, preferably a tert-butyl group.

[0022] The p-hydroxybenzoyl chloride compound has the following structure: wherein R is independently selected from groups having electron donating effect, such as methyl, disubstituted methyl, isobutyl, tert-butyl, preferably a tert-butyl group.

[0023] The step (1) comprises the following steps: dissolving triphosgene in a small amount of triethylamine as an acid binding agent, mixing with w-amino acid or p-hydroxybenzoic acid compound, under the flow of inert gas and stirring, warming reaction, after the reaction is completed, performing vacuum distillation, and collecting the residue, which is w-amino acyl chloride and p-hydroxybenzoyl chloride compound.

[0024] The feeding ratio of each raw material in the step (1) is: w-amino acid / p-hydroxybenzoic acid compound: triphosgene: triethylamine = 30:10-15:3-6, and the w-amino acid / p-hydroxybenzoic acid compound is dissolved in THF solution.

[0025] In the present application, the concentration of the reaction solvent THF is 99.5% (AR analytical purity), the concentration of the triphosgene is 99%, the warming reaction temperature is 25-40°C, the reaction time is 2-3h, the vacuum distillation temperature is 50-60°C, the negative pressure intensity is 0.05-0.1MPa, the yield of the product w-amino acyl chloride and p-hydroxybenzoyl chloride compound is >92%, and the purity is ≥94%.

[0026] The step (2) comprises the following steps: diluting 4-amino-2,2,6,6-tetramethylpiperidine in THF to obtain a 4-amino-2,2,6,6-tetramethylpiperidine solution under inert gas protection, and dropping the w-amino acyl chloride prepared in the step (1) into the 4-amino-2,2,6,6-tetramethylpiperidine solution for reaction, the duration being 1-2h, the reaction time being 1-3h, and the stirring being maintained during the reaction, after the reaction is completed, performing vacuum distillation on the solution, and collecting the residue, which is 6-amino-N-(2,2,6,6-tetramethyl-4-piperidine)-(ethyl-dodecyl) amide.

[0027] The feeding ratio of each raw material in the step (2) is: w-amino acyl chloride: 4-amino-2,2,6,6-tetramethylpiperidine = 0.98-1.02:1, and the 4-amino-2,2,6,6-tetramethylpiperidine is dissolved in THF solution.

[0028] The time for dropping is 1-2h, the reaction temperature is 0-5℃, the reaction time is 1-3h, the temperature for the reduced pressure distillation is 50-60℃, the negative pressure intensity is 0.05-0.1MPa, the yield of the synthesis of 6-amino-N-(2,2,6,6-tetramethyl-4-piperidin)-(ethyl-dodecyl)amide is >93%, and the purity is >97%.

[0029] The step (3) comprises the following steps: diluting 6-amino-N-(2,2,6,6-tetramethyl-4-piperidin)-(ethyl-dodecyl)amide in THF, slowly dropping p-hydroxybenzoyl chloride compound into the reaction under the protection of inert gas, keeping stirring, performing reduced pressure distillation on the solution after the reaction is completed, and collecting the residue, which is 4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidin)amino]ethyl-dodecyl]benzamide compound.

[0030] The time for dropping is 1-2h, the reaction temperature is 0-5℃, the reaction time is 1-3h, the temperature for the reduced pressure distillation is 50-60℃, the negative pressure intensity is 0.05-0.1MPa, the yield of the synthesis of 6-amino-N-(2,2,6,6-tetramethyl-4-piperidin)-(ethyl-dodecyl)amide is >93%, and the purity is >97%.

[0031] The raw material feeding ratio in the step (3) is as follows: 6-amino-N-(2,2,6,6-tetramethyl-4-piperidin)-(ethyl-dodecyl)amide:p-hydroxybenzoyl chloride compound=1:1-1.05, and 6-amino-N-(2,2,6,6-tetramethyl-4-piperidin)-(ethyl-dodecyl)amide is dissolved or dispersed in THF solution.

[0032] The specific synthesis route of the present application is as follows:

[0033] The yield of the final product synthesized by the present application can be up to 95% or more, and the calculation method of the yield is as follows:

[0034]

[0035] Wherein I is the yield (%), m is the mass (g) of the product G prepared, n is the molar amount (mol) of the reactant F or D, and M is the molar mass (g / mol) of the product G.

[0036] Finally, the application also provides the application of the antioxidant in the polyamide composition, the polyamide composition includes PA6 and other polyamide brands, the synthetic antioxidant of the application is added in the mass fraction of about 0.05% to 0.55%, and the S9228 phosphite antioxidant is compounded in the range of 0.05 to 0.5%, wherein the preferred combination is that the antioxidant of the application is compounded with the S9228 antioxidant in the range of 0.2 to 0.4%, more preferably, the antioxidant of the application is compounded with the S9228 antioxidant in the range of 0.25% to 0.2%.

[0037] The application has the following advantages compared with the existing antioxidant:

[0038] 1) The synthetic route is relatively simple, and there is no significant waste liquid hazard;

[0039] 2) The yield is high, and the product collection rate can reach more than 95%;

[0040] 3) The reaction solvent is recycled;

[0041] 4) The antioxidant effect is significantly better than that of the existing antioxidant, and the yellowness index after thermal oxidative aging is obviously decreased. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The infrared spectrum of the product G in Example 5 of the application DETAILED DESCRIPTION

[0043] The synthesis method and performance of the 4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidyl) amino] ethyl-dodecyl] benzamide compound in the application will be further described below. The synthesis methods of 3,5-di-tert-butyl-4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidyl) amino] hexyl] benzamide, 3,5-di-tert-butyl-4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidyl) amino] nonyl] benzamide, and 3,5-di-tert-butyl-4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidyl) amino] dodecyl] benzamide are taken as examples.

[0044] It should be noted that the following examples of the application are only taken as examples of w-amino hexanoic acid, w-amino nonanoic acid, and w-aminododecanoic acid, and do not limit the specific implementation range of the application. In addition, after reading the content of the application, those skilled in the art can make various modifications or modifications to the application, and these equivalent forms also fall within the scope defined by the claims attached to the application.

[0045] The reagents, raw materials and the like involved in the present application are all common commercially available raw materials unless otherwise specified:

[0046] w-amino hexanoic acid / w-amino nonanoic acid / w-amino dodecanoic acid: Shanghai Aladdin Biochem Technology Co., Ltd., purity > 98%;

[0047] 3,5-di-tert-butyl-p-hydroxybenzoic acid: Shanghai Aladdin Biochem Technology Co., Ltd., purity > 98%;

[0048] Tetrahydrofuran: Shanghai Maikeling Biochemical Technology Co., Ltd., AR analytical pure, purity > 99%;

[0049] Triethylamine: Merck KGaA, AR analytical pure, purity > 99%;

[0050] Trifluoroacetic anhydride: Shanghai Aladdin Biochem Technology Co., Ltd., purity > 99%;

[0051] 4-amino-2,2,6,6-tetramethylpiperidine: Shanghai Aladdin Biochem Technology Co., Ltd., purity > 98%;

[0052] NaOH: National Pharmaceutical Group Co., Ltd., purity > 96%.

[0053] Example 1

[0054] (1) w-amino hexanoic acid (30 mmol, 3.93 g) and 3,5-di-tert-butyl-p-hydroxybenzoic acid (30 mmol, 7.5 g) were dispersed in THF (40 mL) solution, a small amount of triethylamine (3 mmol, 0.3 g) was added, trifluoroacetic anhydride (10 mmol, 2.97 g) was dissolved in THF solution (40 ml), and was dropped into the mixed solution using a constant pressure dropping funnel, inert gas was kept flowing and stirring during the reaction, the reaction time was 1 h, the reaction temperature was 25℃, after the reaction was completed, the residue was obtained by distillation under reduced pressure, which was w-amino hexanoyl chloride and 3,5-di-tert-butyl-p-hydroxybenzoyl chloride, the yield was > 89%, the purity was > 92%, the distillation temperature was 55℃, and the liquid after distillation was collected again under negative pressure and used as a solvent for subsequent experiments.

[0055] (2) 4-amino-2,2,6,6-tetramethylpiperidine (25 mmol, 3.9 g) was mixed with THF, w-amino hexanoyl chloride (25.5 mmol, 3.81 g) was slowly dropped into the mixed solution using a constant pressure dropping funnel, the reaction was continued for 1 h, the reaction temperature was 5℃, inert gas was kept flowing and stirring, the reaction was 1 h, after the reaction was completed, the residue was obtained by distillation under reduced pressure, which was 6-amino-N-(2,2,6,6-tetramethyl-4-piperidinyl)-hexanamide, the distillation temperature was 55℃, the yield was > 84.2%, the purity was > 89%. The liquid after distillation was collected again under negative pressure and used as a solvent for subsequent experiments.

[0056] (3) Dissolve 3,5-di-tert-butyl-4-hydroxy-benzoic acid (30 mmol, 7.5 g) in THF (40 mL), then slowly drop 6-amino-N-(2,2,6,6-tetramethyl-4-piperidinyl)-hexanamide (25 mmol, 6.725 g) in THF (40 mL) using a constant pressure dropping funnel for 1 h, maintaining inert gas flow and stirring during the reaction, the reaction time is 2 h, the reaction temperature is 5 °C, after the reaction is completed, the residue is obtained by distillation under reduced pressure, which is 3,5-di-tert-butyl-4-hydroxy-a,a-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidinyl)amino]hexyl]benzamide, the final product yield is > 90.4%, and the purity is > 93%.

[0057] Example 2

[0058] (1) Dissolve w-amino-dodecane acid (30 mmol, 6.45 g) and 3,5-di-tert-butyl-4-hydroxy-benzoic acid (30 mmol, 7.5 g) in THF (40 mL) respectively, add a small amount of triethylamine (4 mmol, 0.404 g), dissolve triphosgene (12 mmol, 3.56 g) in THF (40 mL), and drop the mixture solution using a constant pressure dropping funnel, maintaining inert gas flow and stirring during the reaction, the reaction time is 2.5 h, the reaction temperature is 30 °C, after the reaction is completed, the residue is obtained by distillation under reduced pressure, which is w-amino-dodecane acid chloride and 3,5-di-tert-butyl-4-hydroxy-benzoyl chloride, the yield is > 95%, and the purity is > 97%, the distillation temperature is 55 °C, and the liquid after distillation is collected under negative pressure for use as a solvent in subsequent experiments.

[0059] (2) Dissolve 4-amino-2,2,6,6-tetramethylpiperidine (25 mmol, 3.9 g) in THF, slowly drop w-amino-dodecane acid chloride (25.5 mmol, 6.43 g) into the mixture solution using a constant pressure dropping funnel for 1.5 h, the reaction temperature is 5 °C, maintaining inert gas flow and stirring during the reaction, the reaction time is 1 h, after the reaction is completed, the residue is obtained by distillation under reduced pressure, which is 6-amino-N-(2,2,6,6-tetramethyl-4-piperidinyl)-dodecane acid amide, the distillation temperature is 55 °C, the final yield is > 95%, and the purity is > 97.5%. The liquid after distillation is collected again under negative pressure for use as a solvent in subsequent experiments.

[0060] (3) 3,5-di-tert-butyl-4-hydroxy-a,a-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4- piperidinyl)amino]dodecyl]benzamide was obtained by dissolving 3,5-di-tert- butyl-4-hydroxybenzoyl chloride (25.5 mmol, 6.375 g) in THF (40 mL) and then slowly dropping w-amino-nonyl chloride (25.5 mmol, 4.88 g) into the solution using a constant pressure dropping funnel for 1 h while maintaining a flow of inert gas and stirring. The reaction time was 4 h and the reaction temperature was 3 °C. After completion, the residue was obtained by distillation under reduced pressure. The final product yield was >96% and the purity was >98%.

[0061] Example 3

[0062] (1) w-amino-nonyl acid (30 mmol, 5.19 g) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (30 mmol, 7.5 g) were each dispersed in a THF (40 mL) solution, a small amount of triethylamine (6 mmol, 0.6 g) was added, and triphosgene (10 mmol, 2.97 g) was dissolved in THF (40 mL) and dropped into the mixed solution using a constant pressure dropping funnel while maintaining a flow of inert gas and stirring. The reaction time was 3 h and the reaction temperature was 40 °C. After completion, the residue was obtained by distillation under reduced pressure. The yield was >78% and the purity was >81% for both w-amino-nonyl chloride and 3,5-di-tert-butyl-4-hydroxybenzoyl chloride. The distillation temperature was 55 °C. The liquid after distillation was collected again under reduced pressure and used as a solvent for subsequent experiments.

[0063] (2) 6-amino-N-(2,2,6,6-tetramethyl-4-piperidinyl)-nonyl amide was obtained by dissolving 4-amino-2,2,6,6-tetramethylpiperidine (25 mmol, 3.9 g) in THF and slowly dropping w-amino-nonyl chloride (25.5 mmol, 4.88 g) into the mixed solution using a constant pressure dropping funnel for 2 h while maintaining a flow of inert gas and stirring. The reaction temperature was 0 °C. The reaction time was 2 h. After completion, the residue was obtained by distillation under reduced pressure. The distillation temperature was 55 °C. The final yield was >91% and the purity was >89%. The liquid after distillation was collected again under reduced pressure and used as a solvent for subsequent experiments.

[0064] (3) 3,5-di-tert-butyl-4-hydroxy-a,a-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4- piperidinyl)amino]nonyl]benzamide was obtained by dissolving 3,5-di-tert-butyl-4- hydroxybenzoyl chloride (25.5 mmol, 6.375 g) in THF (40 mL) and then slowly dropping w-amino hexanoyl chloride (25.5 mmol, 3.81 g) into the mixture using a constant pressure dropping funnel for 2 h while maintaining a flow of inert gas and stirring, with a reaction time of 3 h and a reaction temperature of 0°C, after which the residue was obtained by distillation under reduced pressure, with a final product yield of >96.7% and a purity of >98.1%.

[0065] Example 4

[0066] (1) w-amino hexanoic acid (30 mmol, 3.93 g) and 3,5-di-tert-butyl-4- hydroxybenzoic acid (30 mmol, 7.5 g) were each dissolved in THF (40 mL), a small amount of triethylamine (3 mmol, 0.3 g) was added, and triphosgene (15 mmol, 4.45 g) was dissolved in THF (40 mL) and dropped into the mixture using a constant pressure dropping funnel, while maintaining a flow of inert gas and stirring, with a reaction time of 2 h and a reaction temperature of 30°C, after which the residue was obtained by distillation under reduced pressure, with a yield of >96% and a purity of >98%, with a distillation temperature of 55°C, and the liquid after distillation was collected again under reduced pressure and used as a solvent for subsequent experiments.

[0067] (2) 6-amino-N-(2,2,6,6-tetramethyl-4-piperidinyl)hexanamide was obtained by dissolving 4-amino-2,2,6,6-tetramethylpiperidine (25 mmol, 3.9 g) in THF and slowly dropping w-amino hexanoyl chloride (25.5 mmol, 3.81 g) into the mixture using a constant pressure dropping funnel for 1.5 h, with a reaction temperature of 0°C, while maintaining a flow of inert gas and stirring, with a reaction time of 3 h, after which the residue was obtained by distillation under reduced pressure, with a distillation temperature of 55°C, a final yield of >95%, and a purity of >97%. The liquid after distillation was collected again under reduced pressure and used as a solvent for subsequent experiments.

[0068] (3) Dissolve 3,5-di-tert-butyl-4-hydroxybenzoyl chloride (25.5 mmol, 6.375 g) in THF (40 mL), and then slowly add 6-amino-N-(2,2,6,6-tetramethyl-4-piperidine)-hexamethylenediamide (25 mmol, 6.725 g) in THF (40 mL) using a constant pressure dropping funnel for 1 h. During this period, keep the inert gas flowing and stirring. The reaction time is 2 h and the reaction temperature is 3 °C. After the reaction is completed, distill under reduced pressure to obtain the residue, which is 3,5-di-tert-butyl-4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidine)amino]hexyl]benzamide. The yield of the final product is >97% and the purity is >97%.

[0069] Example 5

[0070] (1) W-aminohexanoic acid (30 mmol, 3.93 g) and 3,5-di-tert-butyl-p-hydroxybenzoic acid (30 mmol, 7.5 g) were dispersed in THF (40 mL) solution respectively. A small amount of triethylamine (3 mmol, 0.3 g) was added. Triphosgene (12 mmol, 3.56 g) was dissolved in THF solution (40 mL) and added dropwise to the mixed solution using a constant pressure dropping funnel. During the reaction, inert gas was kept flowing and stirring was maintained. The reaction time was 2 h and the reaction temperature was 30 °C. After the reaction was completed, the residual liquid obtained by vacuum distillation was W-aminohexanoyl chloride and 3,5-di-tert-butyl-p-hydroxybenzoyl chloride. The yields of both were >98% and the purity was >98%. The distillation temperature was 55 °C. The liquid after distillation was collected again under negative pressure and used as a solvent for subsequent experiments.

[0071] (2) 4-Amino-2,2,6,6-Tetramethylpiperidine (25 mmol, 3.9 g) was mixed with THF. W-aminohexanoyl chloride (25.5 mmol, 3.81 g) was slowly added dropwise to the mixed solution using a constant-pressure dropping funnel for 1.5 h. The reaction temperature was 3 °C, with inert gas circulation and stirring maintained for 3 h. After completion, the residue was obtained by vacuum distillation, which was 6-amino-N-(2,2,6,6-tetramethyl-4-piperidine)-hexanoamide. The distillation temperature was 55 °C, and the final yield was >98.4%, with a purity >98.5%. The distilled liquid was collected again under negative pressure and used as a solvent for subsequent experiments.

[0072] (3) Dissolve 3,5-di-tert-butyl-p-hydroxybenzoyl chloride (25.5 mmol, 6.375 g) in THF (40 mL), and then slowly add a THF (40 mL) solution of 6-amino-N-(2,2,6,6-tetramethyl-4-piperidine)-hexamethylenediamide (25 mmol, 6.725 g) using a constant pressure dropping funnel for 1.5 h. During this period, keep the inert gas flowing and stirring. The reaction time is 4 h and the reaction temperature is 3 °C. After the reaction is completed, distill under reduced pressure to obtain the residue, which is 3,5-di-tert-butyl-4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidine)amino]hexyl]benzamide. The yield of the final product is >97.8% and the purity is >98.6%.

[0073] Example 6

[0074] (1) W-aminohexanoic acid (30 mmol, 3.93 g) and 3,5-di-tert-butyl-p-hydroxybenzoic acid (30 mmol, 7.5 g) were dispersed in THF (40 mL) solution respectively. A small amount of triethylamine (6 mmol, 0.6 g) was added. Triphosgene (15 mmol, 4.45 g) was dissolved in THF solution (40 mL) and added dropwise to the mixed solution using a constant pressure dropping funnel. During the reaction, inert gas was kept flowing and stirring was maintained. The reaction time was 3 h and the reaction temperature was 40 °C. After the reaction was completed, the residual liquid obtained by vacuum distillation was W-aminohexanoyl chloride and 3,5-di-tert-butyl-p-hydroxybenzoyl chloride. The yield of both was >78.5% and the purity was >76.8%. The distillation temperature was 55 °C. The liquid after distillation was collected again under negative pressure and used as a solvent for subsequent experiments.

[0075] (2) 4-Amino-2,2,6,6-Tetramethylpiperidine (25 mmol, 3.9 g) was mixed with THF. W-aminohexanoyl chloride (25.5 mmol, 3.81 g) was slowly added dropwise to the mixed solution using a constant-pressure dropping funnel for 2 hours. The reaction temperature was 0°C, and inert gas was maintained while stirring. The reaction was continued for 3 hours. After completion, the residue was obtained by vacuum distillation, which was 6-amino-N-(2,2,6,6-tetramethyl-4-piperidine)-hexanoamide. The distillation temperature was 55°C, and the final yield was >93.2%, with a purity >96.4%. The distilled liquid was collected again under negative pressure and used as a solvent for subsequent experiments.

[0076] (3) Dissolve 3,5-di-tert-butyl-p-hydroxybenzoyl chloride (25.5 mmol, 6.375 g) in THF (40 mL), and then slowly add a THF (40 mL) solution of 6-amino-N-(2,2,6,6-tetramethyl-4-piperidine)-hexamethylenediamide (25 mmol, 6.725 g) using a constant pressure dropping funnel. Continue for 2 h, with inert gas circulation and stirring during the process. The reaction time is 4 h and the reaction temperature is 0 °C. After the reaction is completed, distill under reduced pressure to obtain the residue, which is 3,5-di-tert-butyl-4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidine)amino]hexyl]benzamide. The yield of the final product is >85.9% and the purity is >91%.

[0077] Comparative Example 1

[0078] 30 mmol (3.93 g) of ω-aminohexanoic acid was dispersed in a 40 mL THF solution. Triphosgene (15 mmol (4.45 g) was dissolved in a 40 mL THF solution and added dropwise to the mixture using a constant pressure dropping funnel. Inert gas was kept circulating and stirring was maintained during the reaction. The reaction time was 3 h and the reaction temperature was 40 °C. After the reaction was completed, the residue obtained by vacuum distillation was ω-aminohexanoyl chloride. The yields were all >78.5%, the purity was >76.8%, and the distillation temperature was 55 °C.

[0079] Comparative Example 2

[0080] 4-Amino-2,2,6,6-Tetramethylpiperidine (25 mmol, 3.9 g) was mixed with THF. ω-aminohexanoyl chloride (25.5 mmol, 3.81 g) was then mixed with the THF solution using a constant-pressure dropping funnel and reacted for 1.5 h at 3 °C. An inert gas flow and stirring were maintained for 3 h. After the reaction was complete, the residue was obtained by vacuum distillation, which yielded 6-amino-N-(2,2,6,6-tetramethyl-4-piperidine)-hexanoamide. The distillation temperature was 55 °C, and the final yield was >48.4%, with a purity >39.3%.

[0081] By comparison, it can be seen that the synthesis route and conditions in the examples can achieve the best product synthesis yield and purity.

[0082] To better illustrate the anti-aging ability of the antioxidants of this invention on polyamide materials, the following application examples are described. It should be noted that the antioxidants 1098, light stabilizer 770, and auxiliary antioxidant S9228 involved in this invention are all common commercial models. The thermo-oxidative aging process was carried out in a high-temperature oven, model ESPEC-PH(H)-202, and the yellowness index testing equipment was an integrating sphere colorimeter, model Hunterlab-VIS.

[0083] Application Example 1

[0084] The antioxidant synthesized in Example 2 was added to caprolactam, the raw material for PA6 synthesis, at a mass fraction of 0.5%. Distilled water at a mass ratio of 1.5:1 was added as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230°C and maintained at this temperature for 3 hours, then the temperature was raised to 260°C and maintained for 6 hours, while maintaining the pressure at 1.8 MPa at this temperature. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained, and samples were injection molded and subjected to optical testing after thermo-oxidative aging at 160°C for 4 hours.

[0085] Application Example 2

[0086] The antioxidant synthesized in Example 3 was added to caprolactam, the raw material for PA6 synthesis, at a mass fraction of 0.05%. Distilled water at a mass ratio of 1.5:1 was added as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230°C and maintained at this temperature for 3 hours, then the temperature was raised to 260°C and maintained for 6 hours, while maintaining the pressure at 1.8 MPa at this temperature. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained, and samples were injection molded and subjected to optical testing after thermo-oxidative aging at 160°C for 4 hours.

[0087] Application Example 3

[0088] The antioxidant synthesized in Example 5 was added to caprolactam, the raw material for PA6 synthesis, at a mass fraction of 0.25%. Distilled water at a mass ratio of 1.5:1 was added as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230°C and maintained at this temperature for 3 hours, then the temperature was raised to 260°C and maintained for 6 hours, while maintaining the pressure at 1.8 MPa at this temperature. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained, and samples were injection molded and subjected to optical testing after thermo-oxidative aging at 160°C for 4 hours.

[0089] Application Example 4

[0090] The antioxidant synthesized in Example 5 was added to caprolactam, the raw material for PA6 synthesis, at a mass fraction of 0.25%. 0.2% by mass of auxiliary antioxidant S9228 was added, along with distilled water at a mass ratio of 1.5:1 as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230°C and maintained at this temperature for 3 hours; then the temperature was raised to 260°C and maintained for 6 hours, while the pressure was maintained at 1.8 MPa. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained and injection molded into samples. After thermo-oxidative aging at 160°C for 4 hours, optical testing was performed.

[0091] Application Example 5

[0092] Antioxidant 1098 was added to caprolactam, the monomer raw material for PA6 synthesis, at a mass fraction of 0.25%. Distilled water at a mass ratio of 1.5:1 was added as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230℃ and maintained at this temperature for 3 hours, then the temperature was raised to 260℃ and maintained for 6 hours, while the pressure was maintained at 1.8 MPa at this temperature. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained, and samples were injection molded and subjected to optical testing after thermo-oxidative aging at 160℃ for 4 hours.

[0093] Application Example 6

[0094] Light stabilizer 770 was added to caprolactam, the monomer raw material for PA6 synthesis, at a mass fraction of 0.25%. Distilled water at a mass ratio of 1.5:1 was added as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230℃ and maintained at this temperature for 3 hours, then the temperature was raised to 260℃ and maintained for 6 hours, while the pressure was maintained at 1.8 MPa at this temperature. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained, and samples were injection molded and subjected to optical testing after thermo-oxidative aging at 160℃ for 4 hours.

[0095] Application Example 7

[0096] Antioxidant 1098 and light stabilizer 770 were added to caprolactam, the monomer raw material for PA6 synthesis, at a mass fraction of 0.25%. Distilled water at a mass ratio of 1.5:1 was added as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230℃ and maintained at this temperature for 3 hours, then the temperature was raised to 260℃ and maintained for 6 hours, while maintaining the pressure at 1.8 MPa. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained, and samples were injection molded and subjected to optical testing after thermo-oxidative aging at 160℃ for 4 hours.

[0097] Application Example 8

[0098] Antioxidant 1098 and light stabilizer 770 were added to caprolactam, the monomer raw material for PA6 synthesis, at a mass fraction of 0.25%. 0.2% by mass of auxiliary antioxidant S9228 was added, along with distilled water at a mass ratio of 1.5:1 as a catalyst and pressure feeder. The reaction steps were as follows: the temperature was raised to 230℃ and maintained at this temperature for 3 hours, then raised to 260℃ and maintained for 6 hours, while maintaining a pressure of 1.8 MPa at this temperature. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained and injection molded into samples. After thermo-oxidative aging at 160℃ for 4 hours, optical testing was performed.

[0099] Application Example 9

[0100] Polyamide monomer raw materials and distilled water (mass ratio 1.5:1, used as catalyst and pressure feeder) were added to a reaction vessel. The reaction steps were as follows: the temperature was raised to 230℃ and maintained at this temperature for 3 hours, then the temperature was raised to 260℃ and maintained for 6 hours, while the pressure was maintained at 1.8 MPa at this temperature. The reaction was terminated after the temperature was lowered to room temperature. PA6 polymer was obtained, and samples were injection molded and subjected to optical testing after thermo-oxidative aging at 160℃ for 4 hours.

[0101] The table below compares the amount of antioxidants added and the performance test results in different application examples:

[0102] Amount of addition Antioxidant of the present invention 1098 770 S9228 Yellowness index Application Example 1 0.50％ 7.28 Application Example 2 0.05％ 8.06 Application Example 3 0.25％ 5.81 Application Example 4 0.25％ 0.20％ 3.44 Application Example 5 0.25％ 7.74 Application Example 6 0.25％ 12.33 Application Example 7 0.25％ 0.25％ 5.68 Application Example 8 0.25％ 0.25％ 0.20％ 4.65 Application Example 9 17.93

[0103] It can be seen that, with the same mass percentage of added antioxidants, the antioxidant provided by this invention is more effective than 1098, and its effect is almost equivalent to that of 1098 and light stabilizer 770 under synergistic action, and its effect is even better after being compounded with S9228.

[0104] The above-described embodiments are only some specific embodiments involved in this experiment. The content of this invention is not limited to the above embodiments. The route of this invention can be modified and varied in various ways. However, it should be noted that modifications such as alterations, disassembly, replacement, and combination of the synthesis steps should still be included within the scope of this invention.

Claims

1. An antioxidant with light stability and anti-thermal oxidative aging ability, having the structure shown below: wherein n is an integer from 1 to 11, wherein R is independently selected from the group of electron donating groups methyl, isobutyl, tert-butyl.

2. The method for preparing the antioxidant as described in claim 1, characterized in that, The method comprises: (1) acyl chloride reaction: (2) amidation reaction of 4-amino-2,2,6,6-tetramethylpiperidine: (3) synthesis reaction of 4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidyl) amino] ethyl-dodecyl] benzamide compound:

3. The production method according to claim 2, wherein The step (1) comprises the following steps: dissolving triphosgene in a small amount of triethylamine as an acid binding agent with w-amino acid or p-hydroxybenzoic acid compound as a solvent of tetrahydrofuran, under the flow of inert gas and stirring, warming reaction, after the reaction is completed, vacuum distillation is carried out, and the residue is collected, which is w-amino acyl chloride and p-hydroxybenzoyl chloride compound.

4. The production method according to claim 3, wherein The feeding ratio of each raw material in the step (1) is: w-amino acid / p-hydroxybenzoic acid compound: triphosgene: triethylamine = 30:10-15:3-6, respectively, w-amino acid / p-hydroxybenzoic acid compound is dissolved in THF solution; And / or, the warming reaction temperature is 25-40℃, the reaction time is 2-3h; the vacuum distillation temperature is 50-60℃, and the negative pressure intensity is 0.05-0.1MPa.

5. The production method according to any one of claims 2 to 4, wherein The step (2) comprises the following steps: diluting 4-amino-2,2,6,6-tetramethylpiperidine in THF to obtain 4-amino-2,2,6,6-tetramethylpiperidine solution under inert gas protection, and dropping w-amino acyl chloride prepared in step (1) into 4-amino-2,2,6,6-tetramethylpiperidine solution for reaction, the duration is 1-2h, the reaction time is 1-3h, stirring is maintained during the reaction, after the reaction is completed, the solution is vacuum distilled, and the residue is collected, which is 6-amino-N-(2,2,6,6-tetramethyl-4-piperidyl)-(ethyl-dodecyl) amide.

6. The production method according to claim 5, wherein The feeding ratio of each raw material in the step (2) is: w-amino acyl chloride: 4-amino-2,2,6,6-tetramethylpiperidine = 0.98-1.02:1, 4-amino-2,2,6,6-tetramethylpiperidine is dissolved in THF solution; and / or, the dropping time is 1-2h, the reaction temperature is 0-5℃, the reaction time is 1-3h, the vacuum distillation temperature is 50-60℃, and the negative pressure intensity is 0.05-0.1Mpa.

7. The production method according to any one of claims 2 to 4, wherein The step (3) comprises the following steps: diluting 6-amino-N-(2,2,6,6-tetramethyl-4-piperidyl)-(ethyl-dodecyl) amide in THF, and slowly dropping p-hydroxybenzoyl chloride compound into the reaction under inert gas protection, stirring is maintained, after the reaction is completed, the solution is vacuum distilled, and the residue is collected, which is 4-hydroxy-α,α-dimethyl-N-[6-[(2,2,6,6-tetramethyl-4-piperidyl) amino] ethyl-dodecyl] benzamide compound.

8. The production method according to claim 7, wherein The dropping time is 1-2h, the reaction temperature is 0-5℃, the reaction time is 2-4h, the vacuum distillation temperature is 50-60℃, and the negative pressure intensity is 0.05-0.1Mpa.

9. The production method according to claim 7, wherein The raw material ratio in the step (3) is 6-amino-N-(2,2,6,6-tetramethyl-4-piperidinyl)-(ethyl-dodecyl)amide: p-hydroxybenzoyl chloride = 1:1-1.

05.

10. The antioxidant with light stability and thermal-oxidative aging resistance ability according to claim 1 or the antioxidant with light stability and thermal-oxidative aging resistance ability prepared by the preparation method according to any one of claims 2-9 is applied in a polyamide composition, wherein the polyamide composition comprises polyamide and 0.05-0.55% by mass of the antioxidant with light stability and thermal-oxidative aging resistance ability according to claim 1 or the antioxidant with light stability and thermal-oxidative aging resistance ability prepared by the preparation method according to any one of claims 2-9.

Images