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Preparation for high-carboxyl-content oxalic acid starch

A high carboxyl and starch technology, applied in the field of carboxyl starch, can solve the problems of limiting the wide application of carboxyl starch, low carboxyl content, low oxidation degree of products, etc., and achieve the effect of easy industrial application, high degree of substitution, and mild reaction conditions

Inactive Publication Date: 2008-10-01
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] So far, although the preparation of carboxylated starch has been reported, it is mainly obtained by oxidizing starch, but the degree of oxidation of the product is low, and the carboxyl content is not higher than 4%. The molecular weight of oxidized starch prepared in acidic or alkaline medium decreases. Seriously, the carboxyl content is only effectively controlled by the feed ratio, which limits the wide application of carboxy starch in industry

Method used

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  • Preparation for high-carboxyl-content oxalic acid starch
  • Preparation for high-carboxyl-content oxalic acid starch
  • Preparation for high-carboxyl-content oxalic acid starch

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034]Weigh 50 grams of oxalic acid and dissolve it in 50 milliliters of dimethyl sulfoxide. After the oxalic acid is completely dissolved, move it to a ground flask, add 10 grams of dry starch with a particle size of 50 mesh, and then add 100 milliliters of benzene The solution was mixed with toluene (2:1, volume ratio), and 0.1 ml of pyridine was used as a catalyst for the reaction. Connect a water separator and a condenser, and react with magnetic stirring at a temperature of 100° C. for 18 hours. After the reaction, cool down, add 100 milliliters of ethanol and stir to obtain carboxyl starch precipitate, and the precipitate obtained after suction filtration is washed with 50% ethanol until the pH of the filtrate is 7. The obtained solid was dried at 95° C. for 24 hours, and its carboxyl content was measured to be 88%, with a yield of 85.3%.

[0035] figure 1 Be the infrared spectrogram of embodiment 1 gained oxalate starch; Wherein (a): starch; (b): oxalate starch. It c...

Embodiment 2

[0038] Weigh 50 grams of oxalic acid and dissolve it in 300 milliliters of dimethylformamide. After the oxalic acid is completely dissolved, move it to a ground flask, add 300 grams of dry starch with a particle size of 200 mesh, and then add 300 milliliters of benzene , 3 mL of pyridine was used as a catalyst for the reaction. Connect a water separator and a condenser, and react with magnetic stirring at a temperature of 100° C. for 72 hours. After the reaction, cool down, add 100 milliliters of ethanol and stir to obtain carboxyl starch precipitate, and the precipitate obtained after suction filtration is washed with 50% ethanol until the pH of the filtrate is 7. The obtained solid was dried at 90° C. for 24 hours, and its carboxyl content was measured to be 10.0%, with a yield of 83.5%.

Embodiment 3

[0040] Weigh 50 grams of oxalic acid and dissolve it in 150 milliliters of dimethylacetamide. After the oxalic acid is completely dissolved, move it to a ground flask, add 150 grams of dry starch with a particle size of 100 mesh, and then add 200 milliliters of toluene , 2 ml of concentrated sulfuric acid was used as a catalyst for the reaction. Connect a water separator and a condenser, and react with magnetic stirring at a temperature of 100° C. for 48 hours. After the reaction, cool down, add 100 milliliters of ethanol and stir to obtain carboxyl starch precipitate, and the precipitate obtained after suction filtration is washed with 50% ethanol until the pH of the filtrate is 7. The obtained solid was dried at 100° C. for 18 hours, and its carboxyl content was measured to be 19%, with a yield of 84.4%.

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Abstract

The invention relates to a method for preparing oxalic acid starch with high carboxyl content, which comprises the following steps: (1) 50 portions of oxalic acid measured by mass proportion is dissolved in 50 to 300 portions of polar solvent, then added with 10 to 300 portions of dry starch or gelatinized starch with a particle diameter of 50 to 200 meshes, then respectively added with 100 to 300 portions of organic solvent and 0.1 to 3 portions of catalyst, stirred for reaction for 2 to 72 hours at a temperature between 75 to 130 DEG C; (2) reacting products are cooled to room temperature, added with 100 to 300 portions of ethanol and stirred to obtain carboxyl starch precipitate; 50 percent of ethanol is separated for deposition and washed until the pH of filtering solution is 7; obtained solid is dried for 12 to 24 hours at 90 to 100 DEG C. The method has relatively mild reaction conditions, does not have special requirements for equipment technology, is convenient for industrial application and lowers production cost.

Description

technical field [0001] The invention belongs to the technical field of carboxyl starch, in particular to a method for preparing oxalate starch with high carboxyl content. Background technique [0002] Starch is a polysaccharide composed of a single type of sugar unit, which is naturally synthesized by plants. It is generally composed of amylose and amylopectin. It is the second largest natural polymer on the earth. Its output is second only to cellulose. It is rich in resources and price low. [0003] After physical and chemical modification, the performance of carboxylic Starch has been greatly improved compared with native starch, and its application fields are very wide. In particular, the carboxyl group has a good chelating effect on heavy metal ions, and can be widely used in the adsorption of metal ions and the treatment of industrial wastewater. Zhang Shuxuan et al. used highly cross-linked starch as a raw material to make modified products, which have a good remova...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B31/04
Inventor 张水洞张玉荣黄汉雄
Owner SOUTH CHINA UNIV OF TECH
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