阅读说明：本技术 一种1,2,2,6,6-五甲基哌啶醇的合成方法 (Synthetic method of 1,2,2,6, 6-pentamethylpiperidinol ) 是由 李斌栋 许洪训 李斌洪 王冉 于 2018-06-29 设计创作，主要内容包括：本发明公开了一种1,2,2,6,6-五甲基哌啶醇的合成方法。该方法以2,2,6,6-四甲基哌啶醇和甲醛为原料,在固体酸催化剂的条件下,回流反应2～8小时后,得到产品1,2,2,6,6-五甲基哌啶醇。本发明使用2,2,6,6-四甲基哌啶醇和甲醛作为初始原料,以固体酸为催化剂,催化效率高,操作简单,反应条件温和,产物的选择性和产率都较高,具有广阔的工业应用前景。(The invention discloses a synthesis method of 1,2,2,6, 6-pentamethylpiperidinol. The method comprises the steps of taking 2,2,6, 6-tetramethyl piperidinol and formaldehyde as raw materials, and obtaining a product 1,2,2,6,6-pentamethyl piperidinol after reflux reaction for 2-8 hours under the condition of a solid acid catalyst. The method uses 2,2,6, 6-tetramethyl piperidinol and formaldehyde as initial raw materials and solid acid as a catalyst, and has the advantages of high catalytic efficiency, simple operation, mild reaction conditions, high product selectivity and yield and wide industrial application prospect.)

1. A synthetic method of 1,2,2,6, 6-pentamethylpiperidinol is characterized in that 2,2,6, 6-tetramethylpiperidinol and formaldehyde are used as raw materials, solid acid is used as a catalyst, reflux reaction is carried out for 2-8 hours, and post-treatment is carried out to obtain the 1,2,2,6, 6-pentamethylpiperidinol, wherein the process route is as follows:

2. the method of synthesis according to claim 1, characterized in that it is carried out according to the following steps: adding raw materials of 2,2,6, 6-tetramethyl piperidinol and formaldehyde into a four-neck flask, then quickly adding solid acid, raising the temperature to 80-120 ℃, refluxing for 2 hours, cooling to 50-60 ℃, adding an extracting agent into a reaction system, then adjusting the pH value of the reaction system to 7-8 by using alkali, separating liquid, washing by using water, and finally carrying out reduced pressure distillation on a treated organic phase to obtain the 1,2,2,6,6-pentamethyl piperidinol.

3. A synthesis process according to claim 1 or 2, characterised in that the solid acid is a heteropolyacid, an acidic resin or a molecular sieve.

4. The synthesis method according to claim 1 or 2, wherein the mass ratio of the 2,2,6, 6-tetramethylpiperidinol to formaldehyde is 1: 1-1: 2.

5. The synthesis method according to claim 1 or 2, wherein the mass ratio of the 2,2,6, 6-tetramethylpiperidinol to the solid acid catalyst is 1:0.001 to 1: 0.005.

6. The synthesis method of claim 2, wherein the extractant is benzene, toluene, n-hexane or cyclohexane.

7. A synthesis process according to claim 1 or 2, characterized in that the base is potassium hydroxide, sodium hydroxide or calcium hydroxide.

Technical Field

The invention relates to a synthesis method of 1,2,2,6, 6-pentamethylpiperidinol, belonging to the technical field of organic synthetic chemistry.

Background

The English common name of 1,2,2,6, 6-pentamethylpiperidinol is 1,2,2,6, 6-pentamethyl-4-piperadino, and the structural formula is as follows:is an important intermediate for synthesizing the hindered amine light stabilizer. Due to the excellent characteristics of 1,2,2,6, 6-pentamethylpiperidinol, the 1,2,2,6, 6-pentamethylpiperidinol is widely applied to the field of amine-resistant light stabilizers, and the market demand of the 1,2,2,6, 6-pentamethylpiperidinol is getting larger in recent years, so that the addition value of the 1,2,2,6, 6-pentamethylpiperidinol is larger than that of the 2,2,6, 6-tetramethylpiperidinol, and therefore, a new method for synthesizing the 1,2,2,6, 6-pentamethylpiperidinol becomes a hotspot of chemist research. Existing 1,2,2,6, 6-pentamethineThe production process of the piperidine base alcohol comprises the following steps:

the method comprises the following steps:

reacting 2,2,6, 6-tetramethyl piperidine derivative with formaldehyde under the catalysis of sodium borohydride to generate the 1,2,2,6,6-pentamethyl piperidine derivative.

The method uses sodium borohydride, is expensive, has complicated post-treatment, generates a large amount of boric acid and derivatives thereof, and is not beneficial to industrial production.

The method 2 comprises the following steps:

reacting 2,2,6, 6-tetramethyl piperidinol with methyl iodide in methanol solution at room temperature to obtain 1,2,2,6,6-pentamethyl piperidinol.

The methyl iodide used in the method has low boiling point, is easy to volatilize into gas, is not beneficial to operation, is easy to decompose when exposed to sunlight, decomposes out iodine simple substance, threatens human health, and is not beneficial to industrial production.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method for synthesizing 1,2,2,6, 6-pentamethylpiperidinol, which is aimed at overcoming the disadvantages of the prior art.

The technical scheme for realizing the purpose of the invention is as follows:

the method takes 2,2,6, 6-tetramethyl piperidinol and formaldehyde as initial raw materials and solid acid as a catalyst to synthesize the 1,2,2,6,6-pentamethyl piperidinol. The production process comprises the following steps:

the method specifically comprises the following steps: adding raw materials of 2,2,6, 6-tetramethyl piperidinol and formaldehyde into a four-neck flask, then quickly adding solid acid, raising the temperature to 80-120 ℃, refluxing for 2 hours, cooling to 50-60 ℃, adding an extracting agent into a reaction system, then adjusting the pH value of the reaction system to 7-8 by using alkali, separating liquid, washing by using water, and finally carrying out reduced pressure distillation on a treated organic phase to obtain the 1,2,2,6,6-pentamethyl piperidinol.

According to the above production process, the solid acid is a heteropoly acid, an acidic resin or a molecular sieve.

According to the production process, the mass ratio of the 2,2,6, 6-tetramethyl piperidinol to the formaldehyde is 1: 1-1: 2.

According to the production process, the mass ratio of the 2,2,6, 6-tetramethyl piperidinol to the solid acid catalyst is 1: 0.001-1: 0.005.

According to the above production process, the extractant is benzene, toluene, n-hexane or cyclohexane, preferably benzene.

According to the above production process, the alkali is potassium hydroxide, sodium hydroxide or calcium hydroxide, preferably sodium hydroxide.

Compared with the prior art, the invention has the following advantages:

1. the method takes the solid acid as the catalyst, replaces the traditional process that formic acid and hydrogen halide are taken as the catalyst, avoids the over-strong acidity from corroding reaction equipment, and has the advantages of high catalytic efficiency, simple operation, mild reaction conditions, and higher selectivity and yield of the product.

2. The method has no complex post-treatment operation procedures, is simple in separation, saves energy, reduces consumption and has wide industrial application prospect.

Detailed Description

The present invention is described in detail below with reference to specific examples, but the use and purpose of these examples are only to illustrate the present invention, and do not constitute any limitation to the actual scope of the present invention in any form, and the scope of the present invention is not limited thereto.