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Preparation technology of hydroxypropyl methylcellulose ether (HPMC)

A technology for preparing hydroxypropyl methyl cellulose, which is applied in the production process of hydroxypropyl methyl cellulose ether (HPMC), can solve problems such as low efficiency, poor product controllability, and uneven substitution degree. Achieve stable operation, increase production efficiency, and shorten reaction time

Inactive Publication Date: 2012-12-05
新疆光大山河化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defects of uneven substitution degree, poor product controllability and low efficiency in the prior art, and provide a high-efficiency synthesis process with high reaction uniformity and controllable quality

Method used

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  • Preparation technology of hydroxypropyl methylcellulose ether (HPMC)

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Carry out following steps successively to prepare HPMC (traditional process):

[0024] (1) Prepare 8000Kg of solvent (toluene and isopropanol) of about 17:3, of which 100Kg is reserved for spraying; (2) Add 900Kg of caustic soda and 8000Kg of prepared solvent (toluene: isopropanol) into the reactor ≈17:3, save 1000Kg for spraying); (3) Heat up and stir, heat up to 75°C, keep the temperature for 40 minutes, then cool down to 22°C; (4) Add refined cotton (800Kg) into the reactor, spray, keep the temperature constant (<26°C) Stir for 140 minutes; (5) Add 350Kg of propylene oxide and 1000kg of methyl chloride respectively, and keep the temperature at 55°C and 85°C for 150 minutes and 180 minutes respectively; (6) Add 250Kg of acetic acid into the reactor, Neutralize. Neutralize for 30 minutes, measure the pH value to 6.5-7.5, and then discharge.

Embodiment 2

[0026] Carry out the following steps in order to prepare HPMC (new process), figure 1 Shown:

[0027] (1) Prepare 750Kg of solvent (mass ratio of toluene to isopropanol 3:1), 50Kg of which is reserved for spraying; (2) Open the feeding valve of the alkalization kettle, inject 700Kg of solvent, and close the valve; (3) Open the feeding Valve, add 75Kg of caustic soda, close the valve; (4) heat up to about 75°C, keep the temperature for 30 minutes and then cool down to about 25°C; (5) open the feeding valve, add 80Kg of refined cotton, and spray; (6) Under 0.5 kg pressure and 25°C temperature, alkalinize for 2 hours; (7) Press the material to the etherification kettle, add 95Kg of methyl chloride and 32Kg of propylene oxide; (8) Raise the temperature to 55°C and 85°C constant temperature for 120 minutes and 150 minutes; (9) Press the material to the recovery kettle and add 20kg of acetic acid for neutralization. Neutralize for 30 minutes, measure the pH value to 7±0.5, and the...

Embodiment 3

[0029] Carry out the following steps in order to prepare HPMC (new process), figure 1 Shown:

[0030] (1) Prepare 700Kg of solvent (mass ratio of toluene to isopropanol 4:1), 50Kg of which is reserved for spraying; (2) Open the feeding valve of the alkalization kettle, inject 650Kg of solvent, and close the valve; (3) Open the feeding Valve, add 70Kg of caustic soda, close the valve; (4) heat up to about 85°C, keep the temperature for 30 minutes and then cool down to about 10°C; (5) open the feeding valve, add 90Kg of refined cotton, and spray; (6) Under 0.5 kg pressure and 10°C temperature, alkalinize for 3 hours; (7) Press the material to etherification kettle, add 85Kg of methyl chloride and 38Kg of propylene oxide; (8) Raise the temperature to 55°C and 85°C constant temperature for 130 minutes and 140 minutes; (9) Press the material to the recovery kettle and add 18kg of acetic acid for neutralization. Neutralize for 40 minutes, measure the pH value to 6+0.5, and then di...

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Abstract

The invention relates to a preparation technology of hydroxypropyl methylcellulose ether (HPMC), belonging to the field of the fine chemical industry. The preparation technology comprises the following steps of: 1) independent alkalization: firstly adding 7-8 parts of caustic soda flakes into a diluting agent system in an alkalization kettle; then heating to increase temperature to 70-80DEG C and then decreasing temperature to 10-25DEG C; and finally adding 8-9 parts of refined cotton into the alkalization kettle and keeping the temperature to be constant at 10-25DEG C for 2-3 hours; and 2) two-step etherification: firstly, feeding alkalized materials in the alkalization kettle into an etherification kettle; then adding etherifying agent and increasing temperature to 53-58DEG C for first-step etherification; increasing temperature to 81-87DEG C for second-step etherification; and finally a proper amount of acetic acid into a reactor for neutralization to obtain the HPMC. Due to the preparation technology, the reaction uniformity is obviously improved; and compared with products which are obtained by adopting the traditional production method, the water retention rate of the HPMC prepared by adopting the technology is improved by more than 20 percent and the viscosity is improved by more than 30 percent.

Description

technical field [0001] The invention relates to a production process of hydroxypropyl methylcellulose ether (HPMC), which belongs to the field of fine chemicals. Background technique [0002] my country's cellulose derivatives industry started in the 1960s and has a history of more than 40 years. The development of HMPC in my country was relatively late. Wuxi Research Institute of Chemical Industry first carried out production process research in the 1970s. It was successfully prepared in the former Luzhou Chemical Plant in 1982, and the first production line was established in 1987. Compared with foreign countries, the number of cellulose ether manufacturers in my country is too large, the production capacity is greater than the demand, the scale and technical level of enterprises are quite different, there is a lack of investment in scientific research, and the progress of product updates is slow. With the rapid development of the fine chemical industry, people have highe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B11/08C08B1/08C08B1/10
Inventor 李振坤李军平付延雷田海滨
Owner 新疆光大山河化工科技有限公司
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