Preparation method of 5-butylbenzotriazole

Abstract

The invention discloses a preparation method of 5-butylbenzotriazole, which comprises the following steps: reacting benzotriazole with an alkaline metal compound to obtain benzotriazole salt; the method comprises the following steps: reacting benzotriazole salt with 1-halobutane under the catalysis of a selective catalyst to obtain 5-butylbenzotriazole salt; and hydrolyzing the 5-butylbenzotriazole salt under an acidic condition, so as to obtain the 5-butylbenzotriazole. The preparation method comprises the following steps: self-polymerizing dopamine hydrochloride on the surface of chitosan powder to form polydopamine coated chitosan powder, adding urea, mixing, calcining, increasing the content of nitrogen element, forming an intermediate carrier, impregnating coordinated bimetal with the intermediate carrier, and finally forming the selective catalyst. The conversion rate of the benzotriazole sodium salt reaches 98.7%, the purity of the 5-butylbenzotriazole salt reaches 99.8%, and subsequent preparation of the 5-butylbenzotriazole is facilitated.

Description

Technical Field

[0001] The invention relates to the field of fine chemical materials, and in particular to a method for preparing 5-butylbenzotriazole. Background Art

[0002] Benzotriazole is an important fine chemical product, which can be obtained by the reaction of o-phenylenediamine and sodium nitrite. Add o-phenylenediamine into 50℃ water to dissolve, then add glacial acetic acid, cool to 5℃, add sodium nitrite and stir to react, raise the temperature to 70-80℃, leave at room temperature for 2h, cool, filter out crystals, wash with ice water, dry to obtain a crude product, distill the crude product under reduced pressure, collect the fraction at 201-204℃, and then recrystallize with benzene to obtain a product with a melting point of 96-97℃, with a yield of about 80%.

[0003] Benzotriazole is used in anti-rust oil (grease) products, mostly used in vapor phase corrosion inhibitors for copper and copper alloys, circulating water treatment agents, automotive antifreeze, photographic antifogging agents, polymer stabilizers, plant growth regulators, lubricant additives, ultraviolet absorbers, etc.

[0004] 5-Butylbenzotriazole is a derivative of benzotriazole. As a new corrosion inhibition material, it has a good corrosion inhibition effect on metals such as copper and silver. The existing preparation method is to obtain it through the reaction of benzotriazole salt with 1-halobutane, but it will form a mixture of 4-butylbenzotriazole and 5-butylbenzotriazole, and it is difficult to obtain pure 5-butylbenzotriazole. Summary of the invention

[0005] In order to solve the problems mentioned in the above background technology, the present invention provides a method for preparing 5-butylbenzotriazole.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing 5-butylbenzotriazole comprises the following steps: Benzotriazole reacts with an alkaline metal compound to obtain a benzotriazole salt; Benzotriazole salt and 1-halobutane are catalyzed by a selective catalyst to obtain 5-butylbenzotriazole salt; 5-Butylbenzotriazole salt is hydrolyzed under acidic conditions to obtain 5-butylbenzotriazole; The preparation method of the selective catalyst is as follows: Dispersing chitosan powder and dopamine hydrochloride in ammonia water, heating and stirring to react, drying after the reaction, grinding and mixing the dried product with urea, and calcining under a nitrogen atmosphere to obtain an intermediate carrier; 6,6'-dimethyl-2,2'-bipyridine and diphenyl-2-pyridylphosphine are dispersed in a toluene-ethanol mixed solvent to obtain a ligand solution, aluminum chloride and copper chloride are added to the ligand solution, heated and stirred for reaction, an intermediate carrier is added, stirring is continued, and drying is performed to obtain a selective catalyst.

[0007] Preferably, the mass ratio of the chitosan powder to dopamine hydrochloride is 4:(1-2).

[0008] Preferably, the mass ratio of the dried product to urea is 2:(0.2-0.4).

[0009] Preferably, the mass ratio of the 6,6'-dimethyl-2,2'-bipyridine to diphenyl-2-pyridylphosphine is (2-4): (0.5-1.5).

[0010] Preferably, the mass ratio of the aluminum chloride, copper chloride and intermediate carrier is (6-10): (1-3): (10-30).

[0011] Preferably, the alkaline metal compound is sodium hydroxide or potassium hydroxide, and the molar ratio of the benzotriazole to the alkaline metal compound is 1:(0.95-1.05).

[0012] Preferably, the 1-halobutane is 1-chlorobutane or 1-bromobutane, and the molar ratio of the benzotriazole salt to the 1-halobutane is 1:(0.95-1.05).

[0013] Preferably, the mass ratio of the selective catalyst to the benzotriazole salt is (0.01-0.15):1.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention forms polydopamine-coated chitosan powder by self-polymerization of dopamine hydrochloride on the surface of chitosan powder, adds urea and mixes and then calcines to increase the content of nitrogen element to form an intermediate carrier, and the intermediate carrier is impregnated with the coordinated bimetal to finally form a selective catalyst. By using the selective catalyst of the present invention, the conversion rate of sodium benzotriazole reaches 98.7%, and the purity of 5-butylbenzotriazole salt reaches 99.8%, which is convenient for the subsequent preparation of 5-butylbenzotriazole.

[0015] 2. The present invention regulates the structure of the bimetal through a double ligand (6,6'-dimethyl-2,2'-bipyridine, diphenyl-2-pyridylphosphine), and then loads it on a carrier to form a relatively unique pore structure and surface properties, forming a larger specific surface area and more active sites, greatly improving the efficiency and selectivity of the reaction. Due to the coordination environment of the bimetal, the metal ions form a certain interaction with each other, resulting in a synergistic effect, thereby improving the performance of the selective catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the reaction equation diagram of the present invention. DETAILED DESCRIPTION

[0017] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0018] Preparation Example 1 Disperse 40g chitosan powder and 15g dopamine hydrochloride in 300ml ammonia water (pH 9), stir at 40℃ for 6h, dry and take 20g product and mix with 3g urea, grind and mix thoroughly, and calcine at 400℃ for 4h under nitrogen atmosphere to obtain the intermediate carrier; Disperse 3 g of 6,6'-dimethyl-2,2'-bipyridine and 1 g of diphenyl-2-pyridinylphosphine in 100 ml of a toluene-ethanol mixed solvent (toluene:ethanol volume ratio 1:1) to obtain a ligand solution. Add 8 g of aluminum chloride and 2 g of copper chloride to the ligand solution, stir and react at 50°C for 3 h, add 20 g of the intermediate carrier, continue stirring for 2 h, and dry to obtain a catalyst.

[0019] Preparation Example 2 The difference between this preparation example and preparation example 1 is that 40 g of chitosan powder and 10 g of dopamine hydrochloride are dispersed in 300 ml of ammonia water (pH 9); The rest is exactly the same as Preparation Example 1.

[0020] Preparation Example 3 The difference between this preparation example and preparation example 1 is that 40 g of chitosan powder and 20 g of dopamine hydrochloride are dispersed in 300 ml of ammonia water (pH 9); The rest is exactly the same as Preparation Example 1.

[0021] Preparation Example 4 The difference between this preparation example and preparation example 1 is that after drying, 20 g of the product and 2 g of urea are thoroughly ground and mixed; The rest is exactly the same as Preparation Example 1.

[0022] Preparation Example 5 The difference between this preparation example and preparation example 1 is that after drying, 20 g of the product and 4 g of urea are thoroughly ground and mixed; The rest is exactly the same as Preparation Example 1.

[0023] Preparation Example 6 The difference between this preparation example and preparation example 1 is as follows: 2 g of 6,6'-dimethyl-2,2'-bipyridine and 1 g of diphenyl-2-pyridylphosphine are dispersed in 100 ml of a toluene-ethanol mixed solvent (toluene:ethanol volume ratio 1:1); The rest is exactly the same as Preparation Example 1.

[0024] Preparation Example 7 The difference between this preparation example and preparation example 1 is as follows: 4 g of 6,6'-dimethyl-2,2'-bipyridine and 1 g of diphenyl-2-pyridylphosphine are dispersed in 100 ml of a toluene-ethanol mixed solvent (toluene:ethanol volume ratio 1:1); The rest is exactly the same as Preparation Example 1.

[0025] Preparation Example 8 The difference between this preparation example and preparation example 1 is that 6 g of aluminum chloride and 2 g of copper chloride are added to the ligand solution; The rest is exactly the same as Preparation Example 1.

[0026] Preparation Example 9 The difference between this preparation example and preparation example 1 is that 10 g of aluminum chloride and 2 g of copper chloride are added to the ligand solution; The rest is exactly the same as Preparation Example 1.

[0027] Comparative Preparation Example 1 The difference between this comparative preparation example and preparation example 1 is that after drying, 20 g of the product and 0 g of urea are fully ground and mixed; The rest is exactly the same as Preparation Example 1.

[0028] Comparative Preparation Example 2 The difference between this comparative preparation example and preparation example 1 is as follows: 3 g of 6,6'-dimethyl-2,2'-bipyridine and 0 g of diphenyl-2-pyridylphosphine are dispersed in 100 ml of a toluene-ethanol mixed solvent (toluene:ethanol volume ratio 1:1); The rest is exactly the same as Preparation Example 1.

[0029] Comparative Preparation Example 3 The difference between this comparative preparation example and preparation example 1 is that 0 g of 6,6'-dimethyl-2,2'-bipyridine and 1 g of diphenyl-2-pyridylphosphine are dispersed in 100 ml of a toluene-ethanol mixed solvent (toluene:ethanol volume ratio 1:1); The rest is exactly the same as Preparation Example 1.

[0030] Comparative Preparation Example 4 The difference between this comparative preparation example and preparation example 1 is that 6 g of aluminum chloride and 0 g of copper chloride are added to the ligand solution; The rest is exactly the same as Preparation Example 1. Example 1

[0031] A method for preparing 5-butylbenzotriazole comprises the following steps: 119g of benzotriazole was dispersed in an appropriate amount of ethanol solution, 40g of sodium hydroxide was added, and the mixture was stirred at 60°C for 5h to obtain benzotriazole sodium salt; then 137g of 1-bromobutane and 5g of a selective catalyst (obtained in Preparation Example 1) were added, and the reaction was continued with stirring for 2h. Sampling was performed for detection, and the conversion rate of benzotriazole sodium salt was 98.7%, and the purity of 5-butylbenzotriazole salt was 99.8%. The mixture was filtered, ethanol was recovered, washed with water, and dried to obtain 5-butylbenzotriazole salt; 100g of 5-butylbenzotriazole salt, 80g of sulfuric acid, and 400g of water were evenly dispersed, and stirred at 60°C for 2h to obtain 5-butylbenzotriazole.

[0032] Examples 2-9 and Comparative Examples 1-4 The implementation conditions are the same as those in Example 1, except that the selective catalysts obtained from different preparation examples and comparative preparation examples are used. The results are shown in Table 1.

[0033] Table 1

[0034] According to Table 1, it can be seen from Examples 1-9 that when the selective catalyst prepared by the present invention is used for catalytic reaction, the conversion rate of benzotriazole sodium salt is above 93%, and the purity of 5-butylbenzotriazole salt is relatively high, all above 97%. In Example 1 with the best effect, the conversion rate of benzotriazole sodium salt reaches 98.7%, and the purity of 5-butylbenzotriazole salt reaches 99.8%.

[0035] It can be seen from Example 1 and Comparative Example 1 that without adding urea, the conversion rate of benzotriazole sodium salt is only 73.1%, and the purity of 5-butylbenzotriazole salt is only 85.5%, and the catalytic effect is significantly reduced.

[0036] It can be seen from Example 1, Comparative Examples 2 and 3 that without adding diphenyl-2-pyridinylphosphine, the conversion rate of benzotriazole sodium salt is only 58.5%, and the purity of 5-butylbenzotriazole salt is only 89.6%; Without adding 6,6'-dimethyl-2,2'-bipyridine, the conversion rate of benzotriazole sodium salt is only 39.6%, and the purity of 5-butylbenzotriazole salt is only 81.3%. It can be seen that whether it is the lack of 6,6'-dimethyl-2,2'-bipyridine or the lack of diphenyl-2-pyridinylphosphine, the catalytic performance of the selective catalyst is significantly reduced, but the simultaneous use of the two produces a significant synergistic enhancement effect.

[0037] It can be seen from Example 1 and Comparative Example 4 that without adding copper chloride, the conversion rate of sodium benzotriazole is only 79.6%, and the purity of 5-butylbenzotriazole salt is only 91.4%, and the catalytic performance is reduced to a certain extent.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing 5-butylbenzotriazole, characterized in that: The steps include: Benzotriazole reacts with an alkaline metal compound to obtain a benzotriazole salt; Benzotriazole salt and 1-halobutane are catalyzed by a selective catalyst to obtain 5-butylbenzotriazole salt; 5-Butylbenzotriazole salt is hydrolyzed under acidic conditions to obtain 5-butylbenzotriazole; The preparation method of the selective catalyst is as follows: Dispersing chitosan powder and dopamine hydrochloride in ammonia water, heating and stirring to react, drying after the reaction, grinding and mixing the dried product with urea, and calcining under a nitrogen atmosphere to obtain an intermediate carrier; 6,6'-dimethyl-2,2'-bipyridine and diphenyl-2-pyridylphosphine are dispersed in a toluene-ethanol mixed solvent to obtain a ligand solution, aluminum chloride and copper chloride are added to the ligand solution, heated and stirred for reaction, an intermediate carrier is added, stirring is continued, and drying is performed to obtain a selective catalyst.

2. A method for preparing 5-butylbenzotriazole according to claim 1, characterized in that, The mass ratio of the chitosan powder to dopamine hydrochloride is 4:(1-2).

3. A method for preparing 5-butylbenzotriazole according to claim 1, characterized in that, The mass ratio of the dried product to urea is 2:(0.2-0.4).

4. A method for preparing 5-butylbenzotriazole according to claim 1, characterized in that, The mass ratio of the 6,6'-dimethyl-2,2'-bipyridine to diphenyl-2-pyridylphosphine is (2-4): (0.5-1.5).

5. A method for preparing 5-butylbenzotriazole according to claim 1, characterized in that, The mass ratio of the aluminum chloride, copper chloride and intermediate carrier is (6-10): (1-3): (10-30).

6. A method for preparing 5-butylbenzotriazole according to claim 1, characterized in that, The alkaline metal compound is sodium hydroxide or potassium hydroxide, and the molar ratio of the benzotriazole to the alkaline metal compound is 1:(0.95-1.05).

7. A method for preparing 5-butylbenzotriazole according to claim 1, characterized in that, The 1-halobutane is 1-chlorobutane or 1-bromobutane, and the molar ratio of the benzotriazole salt to the 1-halobutane is 1:(0.95-1.05).

8. A method for preparing 5-butylbenzotriazole according to claim 1, characterized in that, The mass of the selective catalyst and the benzotriazole salt is (0.01-0.15):1.

Images