Method for producing hydroxypropyl methylcellulose

A technology of hypromellose and production method, applied in chemical instruments and methods, mixers with rotary stirring devices, mixers, etc., can solve the problems of low reaction degree, high product yield, and high energy consumption for evaporation recovery , to achieve the effect of reducing energy consumption and high purity

Active Publication Date: 2017-08-29
美信佳中维药业股份有限公司
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

This method has low degree of side reactions and high product yield; but there is a problem of high energy consumption in evaporation and recovery in the solvent recovery link

Method used

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  • Method for producing hydroxypropyl methylcellulose
  • Method for producing hydroxypropyl methylcellulose
  • Method for producing hydroxypropyl methylcellulose

Examples

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Embodiment 1

[0033] 1. Pretreatment of cellulose raw materials

[0034] The refined cotton is crushed into refined cotton blocks with a diameter of about 1-3 cm by the cotton opener, and then enters the pulverizer, and is crushed into 60-100 mesh refined cotton powder by high-speed shearing.

[0035] The existing HPMC production process is to complete the pretreatment process of cellulose raw material - refined cotton through several steps such as opening, crushing, cyclone separation, bag dust removal and packaging.

[0036] The main source of pollution in this process is dust pollution, and the main source of dust is the tiny cellulose particles produced during the pulverization process, causing dust pollution in the air.

[0037] The dust generated in the two steps of unpacking and crushing in the whole pretreatment process is less. The opening step is to put the sheet-shaped refined cotton after manual unpacking on the opening machine, and tear it into loose pieces of 1-3 cm. This st...

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Abstract

The invention relates to a method for producing hydroxypropyl methylcellulose. The method comprises the following steps: 1) performing pretreatment, namely preparing 60-100-mesh cotton powder from purified cotton; 2) alkalifying, namely reacting the powder with alkali to produce alkali cellulose in a mixed solvent; 3) etherification, namely carrying out an etherification reaction among the alkali cellulose, epoxypropane and chloromethane; 4) neutralizing, namely neutralizing the residual alkali with an acid; 5) desolventizing, namely discharging the mixed system into a desolventizing kettle, adding hot water to the top while stirring, introducing water vapor from the bottom of the desolventizing kettle so as to form a solid-liquid-gas three phase; discharging and recovering most of the liquid solvent from a pipeline in the middle of the desolventizing kettle; and 6) performing post-treatment, namely finally centrifuging, granulating, drying, packaging, thereby obtaining the product. According to the method disclosed by the invention, since the recovered reactants participate in the separation process due to the added hot water, compared with the hydroxypropyl methylcellulose (HPMC) prepared by the conventional technical method, the product prepared by the method disclosed by the invention has the advantages that the purity of the crude product is high, and the treatment difficulty of the HPMC at the later stage is reduced.

Description

technical field [0001] The present invention relates to the production method of hypromellose. Background technique [0002] Most of the domestic HPMC production uses a toluene-isopropanol-water mixed system, and the pulverized refined cotton is produced by reacting with propylene oxide and methyl chloride under the action of alkali; a mixture of toluene and isopropanol will be produced during the production process. Gas; by-reaction products of methyl chloride and propylene oxide; waste water contains sodium chloride and sodium acetate. At present, the production process of domestic HPMC is basically: one-step slurry method, the general process steps are as follows: (1), pretreatment: the refined cotton is made into 60-100 mesh refined cotton powder; (2) alkalization: the Refined cotton powder reacts with alkali in the dispersion system of 8-10 times the mixed solvent to generate alkalized cellulose; (3), etherification: alkalized cellulose undergoes etherification reactio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B11/08B01J19/18B01J19/00B01F7/32B01F15/00B01F27/96
CPCB01J19/0066B01J19/18C08B11/08B01F27/96B01F35/41
Inventor 沈小红
Owner 美信佳中维药业股份有限公司
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