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Preparation method of hydroxypropyl methyl cellulose

A technology of hydroxypropyl methylcellulose and refined cotton is applied in the field of preparation of hydroxypropyl methylcellulose, which can solve the problems affecting the amount of etherifying agent, the degree of etherification reaction, the rise of initial concentration of etherifying agent, and the probability of occurrence of side reactions. Increase and other problems to achieve the effect of reducing the occurrence of side reactions, saving dosage, and avoiding useless consumption

Pending Publication Date: 2021-04-23
美信佳中维药业股份有限公司
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  • Summary
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the etherification process, methyl chloride and propylene oxide as etherification reagents will undergo side reactions and be consumed, thus affecting the amount of etherification agent and the degree of etherification reaction
The side reactions of etherification reagents include many kinds, some of which will occur when the etherification reagents are in excess, and the method of adding etherification reagents at one time in the prior art will cause the initial concentration of etherification reagents to rise to a higher level. value, resulting in an increase in the probability of the above-mentioned side reactions, affecting the etherification process

Method used

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  • Preparation method of hydroxypropyl methyl cellulose

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Effect test

Embodiment 1

[0033] Alkalinization: Add 100kg of toluene, 40kg of isopropanol, and 20kg of water into the alkali mixing kettle to mix and prepare a binary organic solvent, then add 80kg of sodium hydroxide to the binary organic solvent, dissolve and configure it to form a mixed lye, and mix the The lye is cooled to 25°C for later use. Add 120kg of refined cotton powder with a particle size of 80 meshes into the reaction kettle, then add the prepared mixed lye into the reaction kettle, control the reaction temperature at 20~35°C, and react for 3 hours under stirring to obtain alkalized refined Cotton powder.

[0034] Etherification: prepare 100kg of methyl chloride and 50kg of propylene oxide, take 25kg of propylene oxide and add it to the reaction kettle, react for 40min under the condition of temperature control at 30~50℃, then add 50kg of methyl chloride, and then raise the temperature to 70~90℃ °C for 60 minutes, after the above reaction process is completed, the temperature is lowered...

Embodiment 2

[0037] Alkalinization: Add 80kg of toluene, 50kg of isopropanol, and 20kg of water into the alkali mixing kettle to form a binary organic solvent, then add 60kg of sodium hydroxide to the binary organic solvent, dissolve and prepare a mixed lye, and mix the The lye is cooled to 25°C for later use. Add 100 kg of refined cotton powder with a particle size of 80 mesh into the reaction kettle, then add the prepared mixed lye into the reaction kettle, control the reaction temperature at 20~35°C, and react for 3 hours under stirring to obtain alkalized refined Cotton powder.

[0038]Etherification: prepare 90kg of methyl chloride and 30kg of propylene oxide, take 15kg of propylene oxide and add it to the reaction kettle, react for 30min under the condition of temperature control at 30~50℃, then add 45kg of methyl chloride, and then raise the temperature to 70~90℃ °C for 50 minutes, after the above reaction process is completed, the temperature is lowered to 25 °C, and the reaction ...

Embodiment 3

[0041] Alkalinization: Add 100kg of toluene, 40kg of isopropanol, and 20kg of water into the alkali mixing kettle to mix and prepare a binary organic solvent, then add 80kg of sodium hydroxide to the binary organic solvent, dissolve and configure it to form a mixed lye, and mix the The lye is cooled to 25°C for later use. Add 120kg of refined cotton powder with a particle size of 80 meshes into the reaction kettle, then add the prepared mixed lye into the reaction kettle, control the reaction temperature at 20~35°C, and react for 3 hours under stirring to obtain alkalized refined Cotton powder.

[0042] Etherification: prepare 105kg of methyl chloride and 45kg of propylene oxide, take 15kg of etherification agent and add it to the reaction kettle, react for 20min under the condition of temperature control at 30~50℃, then add 35kg of methyl chloride, and then raise the temperature to 70~90℃ °C for 40 minutes, after the above reaction process is completed, the temperature is lo...

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Abstract

The invention discloses a preparation method of hydroxypropyl methyl cellulose. Compared with an existing preparation method, the preparation method of hydroxypropyl methyl cellulose provided by the invention has the advantages that the etherification reaction process in the production and preparation process is improved, specifically, chloromethane and epoxypropane are used as etherification reagents, firstly, chloromethane and epoxypropane are uniformly mixed according to a preset ratio to prepare an etherification reagent, then the etherification reagent is gradually added into a reaction kettle in multiple periods to react with refined cotton powder, and each reaction period comprises low-temperature etherification and high-temperature etherification. By means of the scheme, a traditional etherifying agent feeding mode is changed in the etherifying process, the etherifying agent is divided into multiple parts to be fed along with the reaction period, the etherifying agent is made to be in a proper and average concentration level in the whole reaction process, side reactions are reduced, and meanwhile the reaction rate is made to be more uniform.

Description

technical field [0001] The invention relates to a preparation method of hydroxypropyl methylcellulose, which belongs to the field of preparation of hydroxypropyl methylcellulose. [0002] technical background [0003] Hydroxypropyl methylcellulose is a high-tech fine chemical product that is in short supply in China. It is the variety with the widest application and the best performance among all kinds of cellulose. Because the product has excellent thickening, emulsifying, protective colloid, and moisture retention properties, it is widely used in film coating of pharmaceutical preparations, sustained release agents and adhesives, petrochemicals, construction, ceramics, textiles, food, daily chemicals, and synthetic In industries such as resin, medicine, coating and electronics. In developed countries, HPMC is widely used in various industrial fields and daily life. It is called "industrial monosodium glutamate" and has become an indispensable chemical additive. [0004] I...

Claims

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Application Information

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IPC IPC(8): C08B11/08
CPCC08B11/08
Inventor 沈小红叶华
Owner 美信佳中维药业股份有限公司
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