Preparation method and application of dialkyl hydroxylamine salt

Abstract

The invention provides a preparation method and application of dialkyl hydroxylamine salt, and belongs to the technical field of synthetic materials. The dialkyl hydroxylamine is acidified, so that the stability of the compound is improved, the acting time of the dialkyl hydroxylamine salt as an antioxidant in the plastic is prolonged, unreacted organic alkali in the dialkyl hydroxylamine can be removed, the purification effect is achieved, and a certain smell can be removed. The acidification process disclosed by the invention is simple, the operability is high, the dialkyl hydroxylamine salt can be prepared at lower cost, and large-scale industrial production is realized.

Description

Technical Field

[0001] The invention belongs to the field of synthetic materials, and in particular relates to a preparation method and application of a dialkylhydroxylamine salt. Background Art

[0002] Dialkylhydroxylamine antioxidants have the functions of capturing free radicals and decomposing hydroperoxides. As a bifunctional antioxidant, they have been used in the processing and use of polymer materials. They have good color protection and can effectively inhibit the color change of materials during processing and use. At the same time, they have high compatibility and can be well mixed with other materials. In addition, dialkylhydroxylamine also has low volatility and stable high-temperature storage, ensuring that it can remain stable in high-temperature environments.

[0003] At present, high-end products of dialkylhydroxylamine antioxidants are completely dependent on imports, and the production process is almost monopolized by foreign countries. Although there are some domestic manufacturers producing dialkylhydroxylamine (bis(octadecyl)hydroxylamine), the hydroxylamine antioxidants produced domestically have the problem of excessive odor during actual use, and the antioxidant duration in plastics is also shorter than that of imported products. Patent CN113651730A discloses a method for synthesizing bis(octadecyl)hydroxylamine, but there is a problem that triethylamine hydrochloride cannot be completely removed, which leads to low yield, low product purity, and poor antioxidant effect. Therefore, it is very necessary to develop a safer, simpler, and higher purity preparation method for hydroxylamine antioxidants. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of strong odor, low purity, short lasting effect and the like of dialkylhydroxylamine antioxidants, by acidifying the dialkylhydroxylamine antioxidants, thereby greatly improving the antioxidant effect of the dialkylhydroxylamine and broadening its application field in modified plastics.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems: The present invention provides a method for preparing a dialkylhydroxylamine salt, comprising the following steps: (1) Preparation of dialkylhydroxylamine: dissolving hydroxylamine hydrochloride in a solvent, first adding an organic base to react, then adding a halogenated alkane to react, filtering after the reaction, washing with water, and drying to obtain dialkylhydroxylamine; (2) preparing dialkylhydroxylamine salt: mixing the dialkylhydroxylamine obtained in step (1), an acid and a solvent, stirring and reacting for a certain period of time, filtering, washing with water and drying to obtain a dialkylhydroxylamine salt; The molar ratio of each component is as follows: Hydroxylamine hydrochloride: 3-6; Organic base: 10-50; Halogenated alkanes: 6-12; Solvent: 15-150; Acid: 3-6.

[0006] Furthermore, the structural formula of the dialkylhydroxylamine salt is as follows: ; Wherein, the R group is hydrogen, a linear alkyl group or a cyclic alkyl group, X is an acid, n = 0-30, m = 0-30.

[0007] Furthermore, the organic base in step (1) is one or more of pyridine, 1,8-diazobispiro[5.4.0]undec-7-ene, 4-dimethylaminopyridine, N,N-dimethylethylamine, N,N-diethylmethylamine, N,N-dimethylaniline, triethylamine, and triethylenediamine.

[0008] Furthermore, the halogenated alkane in step (1) is XR, X = Cl, Br, I, and R is one or more of a straight-chain alkyl, branched-chain alkyl, or cyclic alkyl group having 1 to 30 carbon atoms.

[0009] Furthermore, the solvent in step (1) is one or more of benzene, toluene, xylene, trimethylbenzene, trifluorotoluene, ether, acetonitrile, dichloromethane, dichloroethane, chloroform, ethyl acetate, tetrahydrofuran, 1,4-dioxane, methyl dioxane, 1,3-dioxane, and propylene oxide.

[0010] Furthermore, the acid in step (2) is one or more of acetic acid, citric acid, tartaric acid, phosphoric acid, formic acid, propionic acid, butyric acid, succinic acid, oxalic acid, malic acid, lactic acid, acetic acid, hydrochloric acid, sulfuric acid, and carbonic acid.

[0011] Furthermore, in step (1), the temperature for the reaction with the organic base is 20-100°C, and the reaction time is 1-48 h; the temperature for the reaction with the halogenated alkane is 20-100°C, and the reaction time is 1-48 h.

[0012] Furthermore, the reaction temperature in step (2) is 20-100° C. and the reaction time is 1-48 h.

[0013] The invention also provides application of the dialkylhydroxylamine salt prepared by the preparation method in plastic anti-oxidation.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) Dialkylhydroxylamine is prepared into salts. The salts formed can cause an increase in the dissociation enthalpy of the trigger bond, thereby significantly improving the thermal properties and improving its stability during processing. Dialkylhydroxylamine is weakly alkaline and reacts with acidic compounds to generate dialkylhydroxylamine salts, which have more stable properties than unsalted dialkylhydroxylamine and thus have better processing stability. The persistence of the dialkylhydroxylamine salts is greatly improved compared to dialkylhydroxylamine.

[0015] (2) The present invention improves the stability of the compound by acidifying the dialkylhydroxylamine, thereby extending the action time of the dialkylhydroxylamine salt as an antioxidant in the plastic. At the same time, the unreacted organic base in the dialkylhydroxylamine can be removed to achieve the effect of purification, and a certain odor can be removed. The acidification process disclosed by the present invention is simple and has strong operability. The dialkylhydroxylamine salt can be prepared at a low cost and can be produced on a large scale in an industrialized manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the H NMR spectrum of the dialkylhydroxylamine acetate synthesized in Example 1 of the present invention.

[0017] Figure 2 This is the H-NMR spectrum of the dialkylhydroxylamine phosphate synthesized in Example 2 of the present invention. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The exemplary implementation modes of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0019] The embodiments of the present invention prepare dialkylhydroxylamine acidified with different acids, complete the preparation of dialkylhydroxylamine salts, and involve the use of dialkylhydroxylamine salts to perform antioxidant modification on polymers.

[0020] The embodiment of the present invention discloses a method for preparing a dialkylhydroxylamine salt, particularly the influence of different acids on dialkylhydroxylamine, and the adjustment of conditions such as reaction temperature and reaction time during the synthesis process. The present invention also relates to the modification of polymers using dialkylhydroxylamine salts, and some auxiliary agents commonly used in existing polymer modification preparation technologies, such as lubricants, auxiliary antioxidants, light stabilizers and heat stabilizers, can also be added. The amount, type and use method of the auxiliary agents are not particularly limited. Specific reference is made to the following examples.

[0021] Example 1 S1. The formula of dialkylhydroxylamine salt is:

[0022] S2. Preparation of dialkylhydroxylamine salts First, hydroxylamine hydrochloride was dissolved in dioxane solvent at 40°C and stirred for 0.5h. The solution was heated to 60°C, triethylamine was added and stirred for 1h, and then 1-bromooctadecane was added. The solution was heated to 100°C and stirred for 8h. After the reaction, the product was cooled and filtered, washed with water and dried to obtain a white powder product, i.e. dialkylhydroxylamine, with a yield of 81%.

[0023] The obtained dialkylhydroxylamine was dissolved in dichloromethane, acetic acid was added at room temperature, and the mixture was stirred for 8 hours. After the reaction, the mixture was washed with water and then with ethanol. After drying, a white powder product was obtained, which was dialkylhydroxylamine acetate, with a chemical formula of CH 3 (CH 2 ) 17 N(OH)(CH 2 ) 17 CH 3 ・CH 3 COOH, yield 92%, NMR data see Figure 1 , the data is as follows: 1 H NMR (400MHz, CDCl 3 , ppm): 0.87-0.89 (m, 6H), 1.25-1.29 (m, 60H), 1.34-1.63 (m, 11H), 1.75 (br, 1H), 3.28 (m, 1H).

[0024] S3. Dialkylhydroxylamine salt as antioxidant to modify HDPE HDPE (HS5820 Sinochem Quanzhou Petrochemical), dialkylhydroxylamine acetate in S2, auxiliary antioxidant 168, calcium stearate, zinc stearate and PPA additive were mixed in a mass ratio of 10000:1:1:3:1:2. The mixture was mixed evenly in a high-speed mixer and then added into a twin-screw extruder from a main feeding port. The set temperatures of the extruder from the feed zone to the die head were 60°C, 90°C, 130°C, 180°C, 200°C, 220°C, 220°C, 210°C, 190°C, 180°C, and the screw speed was 200r / min. Modified HDPE pellets were prepared by extrusion granulation.

[0025] Example 2 S1. The formula of dialkylhydroxylamine salt is:

[0026] S2. Preparation process of dialkylhydroxylamine salt First, hydroxylamine hydrochloride was dissolved in dioxane solvent at 40°C and stirred for 0.5h. The solution was heated to 60°C, triethylamine was added and stirred for 1h, and then 1-bromooctadecane was added. The solution was heated to 100°C and stirred for 8h. After the reaction, the product was cooled and filtered, washed with water and dried to obtain a white powder product, i.e. dialkylhydroxylamine, with a yield of 81%.

[0027] The obtained dialkylhydroxylamine was dissolved in dichloromethane, phosphoric acid was added at room temperature, and the mixture was stirred for 8 hours. After the reaction, the mixture was washed with water and then with ethanol. After drying, a white powder product was obtained, which was dialkylhydroxylamine phosphate, with a chemical formula of CH 3 (CH 2 ) 17 N(OH)(CH 2 ) 17 CH 3 ・H 3 PO 4 , yield 90%, NMR data see Figure 2 , the data is as follows: 1 H NMR (400MHz, CDCl 3 , ppm): 0.87-0.89 (m, 6H), 1.25-1.29 (m, 60H), 1.34-1.77 (m, 8H), 3.52-3.54 (m, 1H), 7.5 (s, 3H).

[0028] S3. Dialkylhydroxylamine salt as antioxidant to modify HDPE HDPE (HS5820 Sinochem Quanzhou Petrochemical), dialkylhydroxylamine phosphate in S2, auxiliary antioxidant 168, calcium stearate, zinc stearate and PPA additive were mixed in a mass ratio of 10000:1:1:3:1:2. The mixture was mixed evenly in a high-speed mixer and then added into a twin-screw extruder from a main feeding port. The set temperatures of the extruder from the feed zone to the die head were 60°C, 90°C, 130°C, 180°C, 200°C, 220°C, 220°C, 210°C, 190°C, 180°C, and the screw speed was 200r / min. Modified HDPE pellets were prepared by extrusion granulation.

[0029] Example 3 S1. The formula of dialkylhydroxylamine salt is:

[0030] S2. Preparation process of dialkylhydroxylamine salt First, hydroxylamine hydrochloride was dissolved in dioxane solvent at 40°C and stirred for 0.5h. The solution was heated to 60°C, triethylamine was added and stirred for 1h, and then 1-bromooctadecane was added. The solution was heated to 100°C and stirred for 8h. After the reaction, the product was cooled and filtered, washed with water and dried to obtain a white powder product, i.e. dialkylhydroxylamine, with a yield of 81%.

[0031] The obtained dialkylhydroxylamine was dissolved in dichloromethane, citric acid was added at room temperature, and the mixture was stirred for 8 hours. After the reaction, the mixture was washed with water and then with ethanol. After drying, a white powder product was obtained, which was dialkylhydroxylamine citrate, with a chemical formula of CH 3 (CH 2 ) 17 N(OH)(CH 2 ) 17 CH 3 ・C 6 H 8 O 7 , yield 90%, NMR data are as follows: 1 H NMR (400MHz, CDCl 3 , ppm): 0.86-0.88 (m, 6H), 1.25-1.34 (m, 60H), 1.51-1.80 (br,7H) 1.89 (m, 4H), 2.49 (m, 1H), 3.19-3.26 (m, 3H), 3.73-3.75(m, 1H), 6.67 (m, 1H).

[0032] S3. Dialkylhydroxylamine salt as antioxidant to modify HDPE HDPE (HS5820 Sinochem Quanzhou Petrochemical), dialkylhydroxylamine citrate in S2, auxiliary antioxidant 168, calcium stearate, zinc stearate and PPA additive were mixed in a mass ratio of 10000:1:1:3:1:2. The mixture was mixed evenly in a high-speed mixer and then added into a twin-screw extruder from a main feeding port. The set temperatures of the extruder from the feed zone to the die head were 60°C, 90°C, 130°C, 180°C, 200°C, 220°C, 220°C, 210°C, 190°C, 180°C, and the screw speed was 200r / min. Modified HDPE pellets were prepared by extrusion granulation.

[0033] Example 4 S1. The formula of dialkylhydroxylamine salt is:

[0034] S2. Preparation of dialkylhydroxylamine salts First, hydroxylamine hydrochloride was dissolved in dioxane solvent at 40°C and stirred for 0.5h. The solution was heated to 60°C, triethylamine was added and stirred for 1h, and then 1-bromooctadecane was added. The solution was heated to 100°C and stirred for 8h. After the reaction, the product was cooled and filtered, washed with water and dried to obtain a white powder product, i.e. dialkylhydroxylamine, with a yield of 81%.

[0035] The obtained dialkylhydroxylamine was dissolved in dichloromethane, tartaric acid was added at room temperature, and the mixture was stirred for 8 hours. After the reaction, the mixture was washed with water and then with ethanol. After drying, a white powder product was obtained, which was dialkylhydroxylamine tartrate, with a chemical formula of CH 3 (CH 2 ) 17 N(OH)(CH 2 ) 17 CH 3 ・C 4 H 6 O 6 , yield 87%, NMR data are as follows: 1 H NMR (400MHz, CDCl 3 , ppm): 0.87-0.89 (m, 6H), 1.25-1.28 (m, 60H), 1.67-1.75 (m, 11H), 1.87-1.89 (m, 2H), 3.22-3.27 (m, 2H).

[0036] S3. Dialkylhydroxylamine salt as antioxidant to modify HDPE HDPE (HS5820 Sinochem Quanzhou Petrochemical), dialkylhydroxylamine tartrate in S2, auxiliary antioxidant 168, calcium stearate, zinc stearate and PPA additive were mixed in a mass ratio of 10000:1:1:3:1:2. The mixture was mixed evenly in a high-speed mixer and then added into a twin-screw extruder from a main feeding port. The set temperatures of the extruder from the feed zone to the die head were 60°C, 90°C, 130°C, 180°C, 200°C, 220°C, 220°C, 210°C, 190°C, 180°C, and the screw speed was 200r / min. Modified HDPE pellets were prepared by extrusion granulation.

[0037] Comparative Example 1 S1. The formula of dialkylhydroxylamine salt is:

[0038] S2. Preparation process of dialkylhydroxylamine salt First, hydroxylamine hydrochloride was dissolved in dioxane solvent at 40°C and stirred for 0.5h. The solution was heated to 60°C, triethylamine was added and stirred for 1h, and then 1-bromooctadecane was added. The solution was heated to 100°C and stirred for 8h. After the reaction, the product was cooled and filtered, washed with water and dried to obtain a white powder product, i.e. dialkylhydroxylamine, with a yield of 81%.

[0039] The obtained dialkylhydroxylamine was dissolved in dichloromethane, and dodecylbenzenesulfonic acid was added at room temperature. The mixture was stirred for 8 hours. After the reaction, it was washed with water and then with ethanol. After drying, a white viscous substance was obtained, which was dialkylhydroxylamine dodecylbenzenesulfonate, with a chemical formula of CH 3 (CH 2 ) 17 N(OH)(CH 2 ) 17 CH 3 ・C 18 H 30 O 3 S, yield 83%, NMR data are as follows: 1 H NMR (400MHz, CDCl 3 , ppm): 0.79-0.89 (m, 14H), 1.12-1.28 (m, 76H), 1.42 (m, 3H), 1.75 (m,3H), 2.51 (m,1H), 3.25-3.29 (m,3H), 3.51-3.53 (m,1H),7.14-7.15(m,2H), 7.75-7.77(m,2H).

[0040] S3. Process of modifying HDPE with dialkylhydroxylamine salt as antioxidant HDPE (HS5820 Sinochem Quanzhou Petrochemical), dialkylhydroxylamine dodecylbenzene sulfonate in S2 of Example 5, auxiliary antioxidant 168, calcium stearate, zinc stearate, and PPA additive were mixed in a mass ratio of 10000:1:1:3:1:2. The mixture was mixed evenly in a high-speed mixer and then added to a twin-screw extruder from a main feeding port. The set temperature of the extruder from the feed zone to the die head was 60°C, 90°C, 130°C, 180°C, 200°C, 220°C, 220°C, 210°C, 190°C, 180°C, and the screw speed was 200r / min. Modified HDPE pellets were prepared by extrusion granulation.

[0041] Comparative Example 2 The preparation steps of dialkylhydroxylamine are the same as those of step S2 in Example 1; HDPE (HS5820 Sinochem Quanzhou Petrochemical), dialkylhydroxylamine, auxiliary antioxidant 168, calcium stearate, zinc stearate and PPA additive were mixed in a mass ratio of 10000:1:1:3:1:2. The mixture was mixed evenly in a high-speed mixer and then added into a twin-screw extruder from a main feeding port. The set temperatures of the extruder from the feed zone to the die head were 60°C, 90°C, 130°C, 180°C, 200°C, 220°C, 220°C, 210°C, 190°C, 180°C, and the screw speed was 200r / min. Modified HDPE pellets were prepared by extrusion granulation.

[0042] The modified HDPE prepared in Examples 1-4 and Comparative Examples 1-2 were repeatedly extruded through a twin-screw extruder, and the change in the yellowness index of the HDPE after multiple extrusions was measured to test the persistence of the dialkylhydroxylamine salt. The results are shown in Table 1.

[0043] Table 1 Yellowness index of modified HDPE prepared in Examples 1-4 and Comparative Examples 1-2 after multiple extrusions through a twin-screw extruder

[0044] The yellowness index of Examples 1-4 remains at a relatively low level after multiple extrusions, which proves that the dialkylhydroxylamine salt has a better antioxidant effect than the unsalified dialkylhydroxylamine.

[0045] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a dialkylhydroxylamine salt, characterized in that: The following steps are involved: (1) Preparation of dialkylhydroxylamine: dissolving hydroxylamine hydrochloride in a solvent, first adding an organic base to react, then adding a halogenated alkane to react, filtering after the reaction, washing with water, and drying to obtain dialkylhydroxylamine; (2) preparing dialkylhydroxylamine salt: mixing the dialkylhydroxylamine obtained in step (1), an acid and a solvent, stirring and reacting for a certain period of time, filtering, washing with water and drying to obtain a dialkylhydroxylamine salt; The molar ratio of each component is as follows: Hydroxylamine hydrochloride: 3-6; Organic base: 10-50; Halogenated alkanes: 6-12; Solvent: 15-150; Acid: 3-6.

2. The preparation method according to claim 1, characterized in that: The structural formula of the dialkylhydroxylamine salt is as follows: ； Wherein, the R group is hydrogen, a linear alkyl group or a cyclic alkyl group, X is an acid, n = 0-30, m = 0-30.

3. The preparation method according to claim 1, characterized in that: The organic base in step (1) is one or more of pyridine, 1,8-diazobispiro[5.4.0]undec-7-ene, 4-dimethylaminopyridine, N,N-dimethylethylamine, N,N-diethylmethylamine, N,N-dimethylaniline, triethylamine, and triethylenediamine.

4. The preparation method according to claim 1, characterized in that: The halogenated alkane in step (1) is XR, X = Cl, Br, I, and R is one or more of a straight-chain alkyl, branched-chain alkyl, or cyclic alkyl group having 1 to 30 carbon atoms.

5. The preparation method according to claim 1, characterized in that: The solvent in step (1) is one or more of benzene, toluene, xylene, trimethylbenzene, trifluorotoluene, ether, acetonitrile, dichloromethane, dichloroethane, chloroform, ethyl acetate, tetrahydrofuran, 1,4-dioxane, methyl dioxane, 1,3-dioxane, and propylene oxide.

6. The preparation method according to claim 1, characterized in that: The acid in step (2) is one or more of acetic acid, citric acid, tartaric acid, phosphoric acid, formic acid, propionic acid, butyric acid, succinic acid, oxalic acid, malic acid, lactic acid, acetic acid, hydrochloric acid, sulfuric acid, and carbonic acid.

7. The preparation method according to claim 1, characterized in that: In step (1), the temperature for the reaction with the organic base is 20-100°C, and the reaction time is 1-48 h; the temperature for the reaction with the halogenated alkane is 20-100°C, and the reaction time is 1-48 h.

8. The preparation method according to claim 1, characterized in that: The reaction temperature in step (2) is 20-100° C. and the reaction time is 1-48 h.

9. Application of the dialkylhydroxylamine salt obtained by the preparation method as claimed in claim 1 in plastic anti-oxidation.

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