Method for preparing C6-site selective carboxylation cellulose by using air as oxidizing agent

A cellulose and selective technology, applied in the field of preparation of oxidized cellulose, can solve the problems of reduced equipment corrosion, high production risk, explosiveness, etc. Effect

Active Publication Date: 2017-04-26
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

NaClO / NaClO 2 The disadvantages of being an oxidizing agent are: corrosive and explosive gases are released when encountering acid; the equipment is severely corroded; strong oxidizing properties easily lead to severe degradation of cellulose; the control of the degree of oxidation is unsatisfactory; the cost is high
In the patent CN201410186699, under the catalysis of sulfate or halide salt, adding H 2 o 2 The method of oxidizing alkali pretreated cellulose as an oxidant, although the oxidation reaction conditions are mild and the corrosion of equipment is reduced, the disadvantages are: 6 Oxidation selectivity is low, while H 2 o 2 There is a risk of explosion
[0008] In summary, the current constraints on C 6 One of the bottlenecks in the large-scale industrialization of position-selective carboxylated cellulose is that the oxidant has serious corrosion to equipment, high cost, and high production risk. Therefore, it is necessary to seek a more environmentally friendly, low-cost, and mild reaction condition. Oxidant solves the technical problems mentioned above

Method used

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  • Method for preparing C6-site selective carboxylation cellulose by using air as oxidizing agent
  • Method for preparing C6-site selective carboxylation cellulose by using air as oxidizing agent
  • Method for preparing C6-site selective carboxylation cellulose by using air as oxidizing agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] (1) Soak 5 g of absolute-dry bleached softwood kraft pulp in a 0.5M sodium hydroxide solution, perform an alkaline pretreatment for 20 minutes, and then wash the cellulose to reduce the pH to 9.5;

[0047] (2) Prepare Na with a total concentration of 0.1M at a molar ratio of 6:4 2 CO 3 / NaHCO 3 200 mL of buffer solution. Dissolve 0.1g TEMPO, 0.25g iron nitrate nonahydrate, and 0.07g potassium chloride in the prepared buffer solution. Then add the above-mentioned alkaline pretreated cellulose into the buffer solution to form a suspension. At room temperature, air is blown into the reaction solution as an oxidant, and the reaction is stirred for 12 hours. The oxygen / primary hydroxyl molar ratio is 3;

[0048] (3) Filter the above reaction stock solution, filter and wash the insoluble oxidized cellulose product with deionized water until neutral, collect and dry to constant weight, and grind into powder. The yield of carboxylated cellulose was 95%, the content of carbo...

Embodiment 2

[0050] (1) Soak 5 g of absolute-dry bleached softwood kraft pulp in a 0.5M sodium hydroxide solution, perform an alkaline pretreatment for 20 minutes, and then wash the cellulose to reduce the pH to 9.5;

[0051] (2) Prepare Na with a total concentration of 0.1M at a molar ratio of 6:4 2 CO 3 / NaHCO 3 200 mL of buffer solution. Dissolve 0.1 g of 4-acetylamino-TEMPO, 0.25 g of iron nitrate nonahydrate, and 0.07 g of potassium chloride in the prepared buffer solution. Then add the above-mentioned alkaline pretreated cellulose into the buffer solution to form a suspension. At room temperature, air is blown into the reaction solution as an oxidant, and the reaction is stirred for 8 hours. The oxygen / primary hydroxyl molar ratio is 2;

[0052] (3) Filter the above reaction stock solution, filter and wash the insoluble oxidized cellulose product with deionized water until neutral, collect and dry to constant weight, and grind into powder. The yield of carboxylated cellulose was ...

Embodiment 3

[0054] (1) Soak 5 g of absolute dry bleached cotton pulp in a 0.5M sodium hydroxide solution, perform an alkaline pretreatment for 30 minutes, and then wash the cellulose to reduce the pH to 9.5;

[0055] (2) Prepare Na with a total concentration of 0.1M at a molar ratio of 6:4 2 CO 3 / NaHCO 3 200 mL of buffer solution. Dissolve 0.1 g of 4-acetylamino-TEMPO, 0.25 g of iron nitrate nonahydrate, and 0.07 g of potassium chloride in the prepared buffer solution. Then add the above-mentioned alkaline pretreated cellulose into the buffer solution to form a suspension. At room temperature, air is blown into the reaction solution as an oxidant, and the reaction is stirred for 12 hours. The oxygen / primary hydroxyl molar ratio is 3;

[0056] (3) Filter the above reaction stock solution, filter and wash the insoluble oxidized cellulose product with deionized water until neutral, collect and dry to constant weight, and grind into powder. The yield of carboxylated cellulose was 96%, th...

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Abstract

The invention provides a method for preparing C6-site selective carboxylation cellulose by using air as an oxidizing agent. The oxidization method is characterized in that a TEMPO derivative and metallic nitrate are utilized as a co-catalyst, potassium chloride is utilized as a promoter, and the air is utilized as a main oxidizing agent to achieve selective oxidation of cellulose primary hydroxyl group. Compared with a traditional cellulose selective oxidization method, the method has the advantages of being economical, environment-friendly, small in equipment corrosion, safe to operate, low in cellulose degradation degree, complete in carboxylation, free of aldehyde group, and the like.

Description

technical field [0001] The invention relates to a preparation method of oxidized cellulose, in particular to a method for oxidizing cellulose and its derivatives under the catalysis of metal nitrate, using air as an oxidizing agent. 6 Selective oxidation of primary hydroxyl to prepare carboxylated cellulose. Background technique [0002] Cellulose is widely derived from plants, tunicates and bacteria. Through photosynthesis, about 75 to 100 billion tons of cellulose are synthesized every year, making it the world's largest natural polymer material. There are three main methods of cellulose modification: etherification, esterification and oxidation. At present, the research and commercialization of etherification and esterification of cellulose are relatively common in China, but the research on the preparation process of oxidative modified cellulose is very weak. [0003] Oxidized cellulose has the characteristics of good biocompatibility, biodegradability, environmental f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B15/04C08B15/02
CPCC08B15/02C08B15/04
Inventor 郑超何光文崔乾王鹏从鑫董科黎源华卫琦
Owner WANHUA CHEM GRP CO LTD
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