CN-122011224-A - Preparation method of environment-friendly sodium carboxymethyl starch

Abstract

The application provides a preparation method of environment-friendly sodium carboxymethyl starch, and relates to the technical field of starch ether preparation. The method comprises the steps of raw material pretreatment, alkalization, etherification auxiliary agent configuration and sectional etherification. The preparation method of sodium carboxymethyl starch provided by the application overcomes the defects of the traditional dry method and solvent method for producing sodium carboxymethyl starch, and the auxiliary agent and etherifying agent which are harmful to human bodies such as chloroacetic acid, methanol, isopropanol and quaternary ammonium salt are avoided in the whole preparation method, and the prepared medical and food grade sodium carboxymethyl starch is simultaneously suitable for industries such as medicine, food and biological products.

Inventors

• WANG GONGXIN
• YU DONGDONG
• WANG NING
• WANG ZITENG
• LI YONG

Assignees

• 山东光大赛路新材料科技有限公司

Dates

Publication Date

20260512

Application Date

20260121

Claims (9)

1. 1. The preparation method of the environment-friendly sodium carboxymethyl starch is characterized by comprising the following steps of: s1, raw material pretreatment, namely respectively crushing solid sodium hydroxide, anhydrous sodium sulfate and solid sodium chloroacetate, and dehydrating starch; s2, alkalizing, namely stirring and mixing the raw materials pretreated in the step S1 in a reaction kettle, heating to 40-43 ℃, and carrying out high-pressure atomization spraying to assist alkalization by absolute ethyl alcohol to obtain an alkalized product; s3, preparing an etherification auxiliary agent, namely uniformly mixing absolute ethyl alcohol and an epoxy active agent to obtain the etherification auxiliary agent; S4, etherification, namely heating the reaction kettle to 76 ℃, vacuumizing to-0.03 MPa, removing redundant water in the kettle, and continuously heating to carry out primary etherification; When the pressure in the kettle is reduced to below 0.3MPa, carrying out secondary etherification by high-pressure atomization spraying 1/3 of the total amount of etherification auxiliary agents; Spraying 2/3 of the total amount of the residual etherification auxiliary agent when the temperature rise of the reaction kettle is slow or the pressure stops rising, and carrying out three-stage etherification; Spraying the residual etherification auxiliary agent when the temperature rise of the reaction kettle is slow or the pressure stops rising, carrying out four-stage etherification, and ending the etherification reaction when the temperature is not raised any more and the pressure is reduced by 0.06-0.1 MPa; S5, post-treatment, namely desolventizing, dehydrating and crushing to obtain a finished product.
2. 2. The method according to claim 1, wherein in step S1, the starch is at least one of tapioca starch, corn starch, and potato starch.
3. 3. The method according to claim 1, wherein in step S1, the water content of the dehydrated starch in step S1 is 4 to 5%.
4. 4. The preparation method of claim 1, wherein in the step S1, the mass ratio of starch, solid sodium hydroxide, anhydrous sodium sulfate and solid sodium chloroacetate is 14 (1-1.4): 1.8-2.4): 6-6.4.
5. 5. The method according to claim 1, wherein in step S2, the alkalizing time is 40-60 min.
6. 6. The preparation method of claim 1, wherein in the step S2, the mass ratio of the absolute ethyl alcohol to the starch is (2.4-3.2) 14, and in the step S3, the mass ratio of the absolute ethyl alcohol to the starch is (2.4-2.8) 14.
7. 7. The preparation method according to claim 1, wherein in the step S3, the mass ratio of the epoxy active agent to the starch is (1-1.4): 14.
8. 8. The method according to claim 1, wherein in step S3, the epoxy activator is at least one selected from the group consisting of 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and trimethylolpropane triglycidyl ether.
9. 9. The preparation method according to claim 1, wherein in the step S4, in the first etherification process, the temperature is 80-83 ℃, the pressure is 0.3-0.35 mpa, and the rotation speed is 30-35 r/min; In the two-stage etherification process, the pressure and the rotating speed are kept unchanged, and the temperature is increased to 83-86 ℃; In the three-stage etherification process, the rotation speed is reduced to 22-28 r/min, the temperature is kept at 85-90 ℃, and the pressure is kept at 0.33-0.35 MPa; In the four-stage etherification process, the rotating speed is increased to 30-35 r/min, the reaction pressure is increased to 0.35-0.4 MPa after 20-25 min, the temperature reaches 90-93 ℃, the stirring reaction is continued, and the reaction is finished when the temperature is not increased any more and the pressure is reduced by 0.06-0.1 MPa.

Description

Preparation method of environment-friendly sodium carboxymethyl starch Technical Field The application relates to the technical field of starch ether preparation methods, in particular to a preparation method of environment-friendly sodium carboxymethyl starch. Background Carboxymethyl starch (CMS) is a representative product of modified starch, is one of ether starch, and is commonly used as sodium salt, so that sodium carboxymethyl starch (CMS-Na) is also called, and is white or yellowish powder or fine particles in appearance, nontoxic, tasteless, difficult to mold, easy to dissolve in water, and stable to light and heat, and forms transparent liquid. Along with the gradual maturity and perfection of the technology for preparing carboxymethyl starch ether and the obvious advantage of the manufacturing cost compared with cellulose, the carboxymethyl starch ether is gradually replaced by carboxymethyl cellulose at present, and is applied to various fields such as papermaking, textile, printing and dyeing, medicine, wastewater treatment, mineral separation, casting, adhesives, cosmetics, building materials, foods, leather, oilfield development, daily chemical industry and the like. The sodium carboxymethyl starch is produced by dry method, water medium method or solvent method. The dry process has the advantages of less solvent addition, less pollution, short flow, low energy consumption and short preparation period, but the reaction raw materials are unevenly mixed, alkalized and agglomerated, and the reaction is unstable, so that the substitution degree of the final carboxymethyl starch is affected. Although the water medium method has simple process flow, the reaction is carried out in a pasting state, the system has high viscosity, the stirring and mixing are difficult, the substitution degree is lower due to the fact that the uniform reaction can not be carried out, and the washing desalting environmental protection treatment cost is high. The solvent method has the advantages of high substitution degree of the product, mild reaction and easy industrialized production, but has the problems of high solvent energy consumption, low conversion rate, high cost and environmental pollution. The patent CN103554282A discloses a preparation method of high-substituted sodium carboxymethyl starch, which comprises the processes of starch alkalization, starch etherification and deep purification, wherein the method comprehensively adopts a multi-step etherification reaction and high-temperature stirring technology, wherein the multi-step etherification reaction and high-temperature stirring technology is to sequentially and stepwise add reaction alkali and starch raw materials into a mixed multielement solvent to carry out an infiltration alkalization reaction, then spray the residual alkali liquor into a reaction system in a mist form in a sub-mode through pressurization under high-temperature stirring, and add an etherifying agent to carry out four etherification processes. Although the method solves the problems of incomplete alkalization and etherification and low conversion rate of the traditional solvent method, the method still has the advantages of high solvent consumption and uses chloroacetic acid which is harmful to human bodies as an etherifying agent, so that the sodium carboxymethyl cellulose prepared by the method can not be simultaneously applied to industries such as medicines, foods, biological products and the like. Disclosure of Invention Aiming at the defects of the prior art, the application provides a preparation method of environment-friendly sodium carboxymethyl starch, which overcomes the defects of sodium carboxymethyl starch produced by the traditional methods such as a dry method, a solvent method and the like, and avoids the use of auxiliary agents and etherifying agents which are harmful to human bodies such as chloroacetic acid, methanol, isopropanol, quaternary ammonium salt and the like in the whole preparation method, and the prepared medical and food-grade sodium carboxymethyl starch is simultaneously suitable for the industries such as medicines, foods, biological products and the like. In order to achieve the above purpose, the technical scheme adopted by the application is as follows: The preparation method of the environment-friendly sodium carboxymethyl starch comprises the following steps: s1, raw material pretreatment, namely respectively crushing solid sodium hydroxide, anhydrous sodium sulfate and solid sodium chloroacetate, and dehydrating starch; s2, alkalizing, namely stirring and mixing the raw materials pretreated in the step S1 in a reaction kettle, heating to 40-43 ℃, and carrying out high-pressure atomization spraying to assist alkalization by absolute ethyl alcohol to obtain an alkalized product; s3, preparing an etherification auxiliary agent, namely uniformly mixing absolute ethyl alcohol and an epoxy active agent to obtain the etherification auxiliary agent; S