KR0152176B1 - A reactor for manufacturing cellulose ether - Google Patents

Abstract

The present invention has a main stirrer (8) in the center of the cylindrical reactor to rotate and stir the raw materials and reactants, the lower part of the reactor is equipped with seven choppers (9), a vacuum device for reducing the reaction pressure in the reactor ( 2), other raw material cellulose inlet (1), sodium hydroxide aqueous solution (3) and inlet, catalyst reservoir (4) and inlet, dimethyl ether reservoir (5) and inlet, methane chloride reservoir (6) and inlet , An alkylene oxide reservoir (7) and an inlet are installed, and the outer periphery of the reactor is equipped with a cooling and heating device (10), a condenser (11) and a slurry transfer port (12) for cooling and recovery of low boiling point materials. The present invention relates to a reactor for synthesizing cellulose ethers.

Description

Reactor for the synthesis of substituted cellulose ether

1 is a block diagram of a reactor for synthesizing cellulose ether of the present invention.

* Explanation of symbols for main parts of the drawings

1: Inlet for finely pulverized cellulose (Pulp) to 0.35mm or less

2: Vacuum apparatus (1st and 2nd vacuum) 3: 50% sodium hydroxide reservoir (7 inlets)

4 catalyst storage 5 dimethyl ether storage

6: film methane storage room 7: alkylene oxide storage room

8: stirrer 9: chopper (7)

10: cooling and heating apparatus 11: condenser for recovery of cooler and low boiling point material

12: Slurry Transfer Hole

The present invention relates to a reactor used for the continuous production process of cellulose ethers in which substituents are uniformly distributed under appropriate reaction conditions.

Since the hydroxy groups present in each repeating unit of the cellulose, which is a natural polymer, have chemical activity, various substituents can be introduced. The properties of the cellulose ether change depending on the type of the substituted group. The characteristics of the cellulose ether also depend on how uniformly the substitution groups are distributed even when they have the same substitution group, and M.S. (Molecular Substitution) values and D.S. It depends on the value of (Degree of Substitution).

In order to obtain a homogeneous distribution of substituents and to have a high M.S. and D.S. value, the cellulose and alkali metal hydroxides must be effectively mixed in the synthesis of alkali cellulose to uniformly substitute the alkali metal to the cellulose. In order to make uniform alkali cellulose, it is important to introduce a reactor that can effectively mix cellulose and alkali metal hydroxides. After making homogeneous alkali cellulose and reacting with etherification agent under appropriate reaction conditions, the M.S.value and D.S.value can be increased.

In addition, various side reactions are generated because the reactivity of the alkylene oxide used in the preparation of hydroxyalkyl cellulose ether is very high. For example, alkylene oxide reacts with water or with other alkylene oxides to produce glycol ethers, and alkylene oxides react with etherification agents to produce ethers. Impurities generated by these side reactions must be removed during the purification of the final product, reducing the overall efficiency of the reaction and increasing the amount of alkylate oxides and etherification agents, resulting in cost increase.

The manufacturing process of such a cellulose ether and the reactor used for this process are already disclosed by various documents, and the matter disclosed by the patent document is as follows.

German Patent No. 765,441 discloses a process for the production of cellulose ethers in which an alkali cellulose and an etherification agent are produced in a reactor having a single screw or multi screw.

The manufacturing process of the polysaccharide ether according to US Patent No. 4,015,067 is as follows. With air removed in the stirrer, a mixed solution of cellulose, 50% sodium hydroxide aqueous solution, propylene oxide and methane chloride was injected for 30 minutes and stirred. This mixed solution is continuously transferred to a tubular reactor. The reactor is kept at 80 ° C. for reaction. M.S. of hydroxypropylmethylcellulose obtained at this time. Value is 0.17 and D.S. As the value is 1.74, the reaction efficiency of propylene oxide is 1.3%, and the reaction efficiency of methane chloride is 5.4%.

U.S. Patent Nos. 4,310,663 and 4,363,784 describe a continuous process for the preparation of hydroxyalkyl cellulose or mixed cellulose ethers and is an invention made using an apparatus consisting of three stirrers and tubular reactors. After mixing cellulose, alkali metal hydroxide, organic solvent, and etherification agent with each other using three stirrers and pumps, the reaction mixture solution is transferred to the tubular reactor using a metering pump to increase the reactor temperature. It reacts at -120 degreeC. When preparing hydroxyethyl cellulose using this continuous process, the reaction efficiency of ethylenoxide is 9.4%.

As described above, the manufacturing process of the disclosed patent has a general problem, in which cellulose and an aqueous sodium hydroxide solution are mixed using one or three stirrers, but no uniformly substituted sodium cellulose is produced, thus the reaction efficiency of the etherification agent. It was low, and the autonomous cost was high because the stirrer and the reactor were separately installed.

In addition, U.S. Patent No. 4,015,067 cannot be a complete continuous process because the temperature must be controlled when transferring to a tubular reactor (US Patent No. 4,310,663), and U.S. Patent Nos. 4,310,663 and 4,363,784 are uniform nit due to low efficiency of the stirrer. In order to make fume cellulose, the reaction solution was forced to be mixed by using a pump. In both patents, the reaction efficiency was low because the reaction temperature was reacted at only one temperature while using methane chloride and propylene oxide as etherification agents.

In order to solve this problem, in the present invention, a main stirrer and seven choppers are introduced into the reactor to effectively mix the reactants and react in the reactor. In addition, the aqueous solution of sodium hydroxide was sprayed around seven choppers, and the internal pressure of the reactor was reduced at the first and second reduced pressures, so that the spraying was easily carried out when the aqueous sodium hydroxide solution and the etherification agent were added, thereby spreading the entire reactor evenly. And the reaction temperature was adjusted in two stages to increase the reaction efficiency.

Hereinafter will be described in detail with reference to the accompanying drawings the configuration of the reactor of the present invention.

In the center of the cylindrical reactor there is a main stirrer (8) to rotate and stir the raw materials and reactants, the lower part of the reactor is equipped with seven choppers (9), the vacuum device (2) for reducing the reaction pressure in the reactor Cellulose inlet (1), sodium hydroxide aqueous solution (3) and inlet catalyst reservoir (4) and inlet, dimethyl ether reservoir (5) and inlet, methane chloride reservoir (6) and inlet, alkylene oxide A reservoir 7 and an inlet are installed, and a condenser 11 and a slurry conveyance port 12 for cooling and heating apparatus 10 and cooling and recovery of low boiling point materials are mounted outside the reactor.

Hereinafter, a method of preparing cellulose ether using the reactor of the present invention is as follows.

(a) Put cellulose (1 in FIG. 1) finely pulverized to 0.35 mm or less into a reactor and firstly depressurize (70 in 2) to 70-80 torr to remove tksthh; (b) 50% aqueous sodium hydroxide solution (3 in FIG. 1) and 1-5% by weight of catalyst (4 on the first side) are injected into the reactor, followed by vigorous stirring for 30 to 50 minutes (8, 9) to prepare sodium cellulose; (c) Secondary pressure reduction (2 in FIG. 1) at 70 to 80 torr, followed by 3 minutes in order of dimethyl ether (5 in FIG. 1), methane chloride (6 in FIG. 1), and alkylene oxide (7 in FIG. 1). Input by; (d) maintaining the internal temperature of the reactor at 62 to 68 DEG C for 35 to 45 minutes to conduct a first reaction; (e) raising the internal temperature of the reactor to 85 to 95 ° C. to react the secondary reaction for 35 to 45 minutes to synthesize cellulose ether in a two step reaction; (f) Low boiling point dimethyl ether and unreacted methane chloride are recovered and reused (11 in Fig. 1).

Claims (5)

In the center of the cylindrical reactor there is a main stirrer (8) to rotate and stir the raw materials and reactants, the lower part of the reactor is equipped with seven choppers (9), the vacuum device (2) for reducing the reaction pressure in the reactor Cellulose inlet (1), sodium hydroxide solution reservoir (3) and inlet, catalyst reservoir (4) and inlet, dimethyl ether reservoir (5) and inlet, methane chloride reservoir (6) and inlet, alkylene An oxide reservoir (7) and an inlet are installed, and the outer periphery of the reactor is equipped with a cooling and heating device (10), a condenser (11) and a slurry transfer port (12) for cooling and recovery of low boiling point materials. Reactor for Synthesizing Cellulose Ether 2. The cellulose according to claim 1, wherein the vacuum apparatus 2 is characterized in that the internal pressure of the reactor is first reduced or second reduced to facilitate spraying when the aqueous solution of sodium hydroxide and the etherifying agent are added, so as to spread evenly throughout the reactor. Reactor for ether synthesis The reactor for synthesizing cellulose ethers according to claim 1, wherein the seven choppers 9 are for effectively mixing and reacting reactants. The reactor for synthesizing cellulose ethers according to claim 1, wherein sodium hydroxide is sprayed around seven choppers. Cellulose (1) finely pulverized to 0.35 mm or less is placed in a reactor to remove oxygen by first depressurizing (2) to 70 to 80 torr; Sodium cellulose was prepared by injecting 50% aqueous sodium hydroxide solution (3) and 1-5% by weight of catalyst (4) into the reactor, followed by vigorous stirring (8,9) for 30-50 minutes; Secondary depressurization (2) to 70 to 80 torr, followed by 3 minute intervals in the order of dimethyl ether (5), methane chloride (6) and alkylene oxide (7); Maintaining the internal temperature of the reactor at 62 to 68 ° C. for 35 to 45 minutes to conduct a first reaction; Raising the reactor internal temperature to 85 to 95 ° C. to react the secondary reaction for 35 to 45 minutes to synthesize cellulose ether in a two step reaction; How to use a reactor for synthesizing cellulose ethers, characterized by recovering and reusing (11) low-boiling substances dimethyl ether and unreacted methane chloride