Process for preparing hydroxy ethyl cellulose

A technology of hydroxyethyl cellulose and cellulose, applied in the field of polymer chemistry, can solve the problems of product uniformity and purity limitation, poor product uniformity and purity, easy to be destroyed by heating, etc., and achieve low price and good uniformity , the effect of easy operation

Inactive Publication Date: 2002-11-06
WUHAN UNIV
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Problems solved by technology

For a long time, heterogeneous reactions have been used in the industrial production of cellulose esters and ether derivatives, which limits the uniformity and purity of the products, especially for partially substituted cellulose derivatives.
So far, cellulose is only suitable for homogeneous derivatization reactions in a few nonaqueous solvents, but these are expensive, such as N,N-dimethylacetamide (DMAc) / lithium chloride (LiCl) and dimethyl sulfoxide (DMSO) / SO 2 / diethylamine two solvent systems
High-purity, high-uniformity, high-yield cellulose acyl esters, carbamates and sulfonate derivatives have been successfully synthesized in DMAc / LiCl solvent (C.L McCormick, et al., J.Polym.Sci., Polym.Lett.Ed., 1979,17,479), but its disadvantage is that DMAc is easily destroyed when heated in a strong alkaline solution (S.Langlois, et al., Bull.Soc.Chim.France, 1964 , 812), and heating is an essential condition for etherification with haloalkane as etherification agent
The homogeneity and purity of the product obtained by this method are poor

Method used

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Embodiment Construction

[0009] The technical scheme of the present invention is further described below in conjunction with specific embodiment:

[0010] 6 grams of sodium hydroxide (NaOH) and 4 grams of urea were dissolved in 90 grams of distilled water to form a 6wt% NaOH / 4wt% urea aqueous solution. Disperse 2 g of cellulose powder (CF-11, degree of polymerization DP = 220, Whatman, UK) in 98 g of the above-mentioned sodium hydroxide / urea aqueous solution, stir vigorously for 5 minutes, and then freeze in a refrigerator (0° C.) for 12 After 4 hours, stir and thaw in an ice-water bath at 4 °C to obtain a clear solution. Take 50 grams of the cellulose aqueous solution, add 1 mL of 2-chloroethanol dropwise directly in an ice-water bath at 4°C and stir for 1 hour. After the viscosity of the solution increases significantly, raise the temperature to 50°C and stir for 12 hours, then add it to glacial acetic acid and the reaction solution to pH=5-6 to stop the reaction. Pour the reaction solution into a...

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Abstract

During the preparation process, cellulose is dissolved completely in water solution with sodium hydroxide of 6 wt% and urea of 4 wt%, and is made to produce homogeneous hydroxyethylation with 2-chloroethanol in the water solution to produce water soluble hydroxyethyl cellulose. The cellulose has no obvious degradation during the reaction. The new process of preapring hydroxyethyl cellulose has low cost, no pollution, high product purity and good product homogeneity.

Description

technical field [0001] The invention relates to a preparation method of hydroxyethyl cellulose, in particular to a method for preparing hydroxyethyl cellulose by homogeneous hydroxyethylation in a sodium hydroxide / urea aqueous solution system, which belongs to the field of macromolecular chemistry. Background technique [0002] Due to the complex morphological structure of the coexistence of crystalline and amorphous regions in natural cellulose, as well as the influence of intramolecular and intermolecular hydrogen bonds, it is difficult to dissolve in common solvents for homogeneous derivatization reactions. For a long time, heterogeneous reactions have been used in the industrial production of cellulose esters and ether derivatives, which limits the uniformity and purity of products, especially partially substituted cellulose derivatives. So far, cellulose is only suitable for homogeneous derivatization reactions in a few nonaqueous solvents, but these are expensive, such...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B15/00
Inventor 周琪张俐娜
Owner WUHAN UNIV
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