Method for preparing 2,6-dimethyl-2-heptanol

Abstract

The invention discloses a method for preparing organic matter in the technical field of chemical industry, in particular a method for preparing 2,6-dimethyl-2-heptanol. The present invention uses benzylmagnesium chloride or benzylmagnesium bromide as an initiator to prepare methyl Grignard reagent, then carries out Grignard reaction with 2-methyl-2-hepten-6-one, and then catalyzes hydrogenation to synthesize 2 , 6-Dimethyl-2-heptanol. The initiator prepared in the present invention is relatively stable in properties and easy to store. Compared with commonly used initiators, it has the characteristics of fast initiation speed, strong versatility, small dosage, convenient storage, and low toxicity, and is especially suitable for large-scale production. Preparation of Reagent's Reagent. The preparation of the product of the present invention has more safety and higher product yield. The product of the invention can be widely used in the formula of daily chemical essence.

Description

technical field

[0001] The invention belongs to the technical field of chemical industry and relates to a preparation method of 2,6-dimethyl-2-heptanol. technical background

[0002] 2,6-Dimethyl-2-heptanol (2,6-Dimethyl-2-heptanol) has fresh lily-of-the-valley and citrus notes, and can be used in daily chemical fragrance formulas.

[0003] The main methods for preparing 2,6-dimethyl-2-heptanol are 6-methyl-5-hepten-2-one and methylmagnesium chloride or methylmagnesium bromide or methylmagnesium iodide. Based Grignard reagent reaction, and catalytic hydrogenation; or use 2-methyl-6-heptanone as raw material for Grignard reaction.

[0004]

[0005] Halogenated hydrocarbon reacts with metal magnesium in anhydrous ether or tetrahydrofuran to generate alkylmagnesium halide RMgX. This organic magnesium compound is called Grignard Reagent. Grignard reagents can undergo addition reactions with compounds such as aldehydes and ketones, and generate alcohols after hydrolysis. Thi...

Examples

Embodiment 1

[0025] Preparation of benzylmagnesium chloride: prepare 12.7g (0.1mol) of benzyl chloride and 60mL of tetrahydrofuran, stir for 5min and set aside. Add 2.4g (0.1mol) of freshly treated magnesium powder, 15mL tetrahydrofuran, and 15mL toluene into a clean and dry 250mL four-necked bottle. After stirring for 5 minutes, slowly raise the temperature to 60°C. After stabilization, slowly add 5% of the prepared Benzyl chloride, tetrahydrofuran mixture, the reaction exotherm is obvious, when the temperature no longer rises, it indicates that the reaction has been initiated. Continue to drop the remaining benzyl chloride and tetrahydrofuran mixture, the reaction is obviously exothermic, keep cooling during the process, the reaction temperature is controlled at 10-60°C, the drop is completed in about 6-8 hours, and the reaction is completed after continuing the reaction for 3 hours. Store the prepared initiator in a sealed reagent bottle for later use.

Embodiment 2

[0027] Preparation of benzyl magnesium bromide: prepare 17.1 g (0.1 mol) of benzyl bromide and 100 mL of tetrahydrofuran, stir for 5 min and set aside. Add 2.4g (0.1mol) of freshly treated magnesium powder, 30mL tetrahydrofuran, and 10mL toluene into a clean and dry 250mL four-neck bottle, stir for 5 minutes, then slowly raise the temperature to 60°C, and slowly add 5% of the prepared solution after stabilization The mixture of benzyl bromide and tetrahydrofuran, the reaction exotherm is obvious, and the reaction has been initiated when the temperature no longer rises. Continue to drop the remaining mixture of benzyl bromide and tetrahydrofuran, the reaction is obviously exothermic, keep cooling during the process, the reaction temperature is controlled at 10-60°C, the drop is completed after about 6-10 hours, and the reaction is completed after continuing the reaction for 3 hours. Store the prepared initiator in a sealed reagent bottle for later use.

Embodiment 3

[0029] Preparation of 2,6-dimethyl-5-hepten-2-ol: Add 24g (1mol) of freshly treated magnesium powder and 240mL tetrahydrofuran into a clean, dry 1000mL four-necked flask, and stir at room temperature for 5min. Then add 10g of prepared benzylmagnesium bromide and 4g of benzyl bromide, and the reaction will start rapidly under stirring. After the initiation is complete, slowly feed in methyl chloride and react in a boiling state. The magnesium powder will disappear completely in about 3 to 6 hours. Continue Reaction 1h. Place the prepared four-neck flask of methylmagnesium chloride Grignard reagent in the cooling system, start stirring, and slowly add 126g (1mol) of 6-methyl-5-heptene-2- For ketone, the dropwise addition time is about 2 to 5 hours. After the dropwise addition, continue to react at room temperature for 1 hour. After the reaction, add 200mL of toluene, and recover tetrahydrofuran under normal pressure. After the recovery, slowly add 250g of 20% acetic acid solutio...

technical field

[0001] The invention belongs to the technical field of chemical industry and relates to a preparation method of 2,6-dimethyl-2-heptanol. technical background

[0002] 2,6-Dimethyl-2-heptanol (2,6-Dimethyl-2-heptanol) has fresh lily-of-the-valley and citrus notes, and can be used in daily chemical fragrance formulas.

[0003] The main methods for preparing 2,6-dimethyl-2-heptanol are 6-methyl-5-hepten-2-one and methylmagnesium chloride or methylmagnesium bromide or methylmagnesium iodide. Based Grignard reagent reaction, and catalytic hydrogenation; or use 2-methyl-6-heptanone as raw material for Grignard reaction.

[0004]

[0005] Halogenated hydrocarbon reacts with metal magnesium in anhydrous ether or tetrahydrofuran to generate alkylmagnesium halide RMgX. This organic magnesium compound is called Grignard Reagent. Grignard reagents can undergo addition reactions with compounds such as aldehydes and ketones, and generate alcohols after hydrolysis. Thi...

Examples

Embodiment 1

[0025] Preparation of benzylmagnesium chloride: prepare 12.7g (0.1mol) of benzyl chloride and 60mL of tetrahydrofuran, stir for 5min and set aside. Add 2.4g (0.1mol) of freshly treated magnesium powder, 15mL tetrahydrofuran, and 15mL toluene into a clean and dry 250mL four-necked bottle. After stirring for 5 minutes, slowly raise the temperature to 60°C. After stabilization, slowly add 5% of the prepared Benzyl chloride, tetrahydrofuran mixture, the reaction exotherm is obvious, when the temperature no longer rises, it indicates that the reaction has been initiated. Continue to drop the remaining benzyl chloride and tetrahydrofuran mixture, the reaction is obviously exothermic, keep cooling during the process, the reaction temperature is controlled at 10-60°C, the drop is completed in about 6-8 hours, and the reaction is completed after continuing the reaction for 3 hours. Store the prepared initiator in a sealed reagent bottle for later use.

Embodiment 2

[0027] Preparation of benzyl magnesium bromide: prepare 17.1 g (0.1 mol) of benzyl bromide and 100 mL of tetrahydrofuran, stir for 5 min and set aside. Add 2.4g (0.1mol) of freshly treated magnesium powder, 30mL tetrahydrofuran, and 10mL toluene into a clean and dry 250mL four-neck bottle, stir for 5 minutes, then slowly raise the temperature to 60°C, and slowly add 5% of the prepared solution after stabilization The mixture of benzyl bromide and tetrahydrofuran, the reaction exotherm is obvious, and the reaction has been initiated when the temperature no longer rises. Continue to drop the remaining mixture of benzyl bromide and tetrahydrofuran, the reaction is obviously exothermic, keep cooling during the process, the reaction temperature is controlled at 10-60°C, the drop is completed after about 6-10 hours, and the reaction is completed after continuing the reaction for 3 hours. Store the prepared initiator in a sealed reagent bottle for later use.

Embodiment 3

[0029] Preparation of 2,6-dimethyl-5-hepten-2-ol: Add 24g (1mol) of freshly treated magnesium powder and 240mL tetrahydrofuran into a clean, dry 1000mL four-necked flask, and stir at room temperature for 5min. Then add 10g of prepared benzylmagnesium bromide and 4g of benzyl bromide, and the reaction will start rapidly under stirring. After the initiation is complete, slowly feed in methyl chloride and react in a boiling state. The magnesium powder will disappear completely in about 3 to 6 hours. Continue Reaction 1h. Place the prepared four-neck flask of methylmagnesium chloride Grignard reagent in the cooling system, start stirring, and slowly add 126g (1mol) of 6-methyl-5-heptene-2- For ketone, the dropwise addition time is about 2 to 5 hours. After the dropwise addition, continue to react at room temperature for 1 hour. After the reaction, add 200mL of toluene, and recover tetrahydrofuran under normal pressure. After the recovery, slowly add 250g of 20% acetic acid solutio...

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