Hydroxyethyl cellulose is an important cellulose derivative. Due to the advantages of abundant raw material resources, renewable, biodegradable, non-toxic, good biocompatibility, and large yield, its research and application have attracted much attention. . Viscosity value is a very important performance index of hydroxyethyl cellulose. In this paper, hydroxyethyl cellulose with viscosity value above 5×104mPa·s and ash value less than 0.3% was prepared by liquid-phase synthesis method through alkalization and etherification two-step process.

The alkalization process is the preparation process of alkali cellulose. In this paper, two alkalization methods are used. The first method is to use acetone as a diluent. The cellulose raw material is directly basified in a certain concentration of sodium hydroxide aqueous solution. After the basification reaction is carried out, an etherifying agent is added to directly carry out the etherification reaction. The second method is that the cellulose raw material is alkalized in an aqueous solution of sodium hydroxide and urea, and the alkali cellulose prepared by this method must be squeezed to remove excess lye before the etherification reaction. The alkali cellulose prepared by different methods was analyzed by infrared spectroscopy and X-ray diffraction. According to the properties of the products prepared by the etherification reaction, the selection method is determined.

In order to determine the best etherification synthesis process, the reaction mechanism of antioxidant, lye and glacial acetic acid in the etherification reaction was analyzed first. Then formulate the experimental program of single factor reaction, determine the factors that have a greater impact on the performance of the prepared hydroxyethyl cellulose, and use the viscosity of the product’s 2% aqueous solution as a reference index. The experimental results show that factors such as the selected diluent amount, the amount of ethylene oxide added, the alkalization time, the temperature and time of the first reaction, the temperature and time of the second reaction all have a great influence on the performance of the product. An orthogonal experiment scheme with seven factors and three levels was drawn up, and the effect curve drawn from the experimental results could visually analyze the primary and secondary factors and the influence trend of each factor. In order to prepare products with higher viscosity values, an optimized experimental scheme was formulated, and the optimal scheme for preparing hydroxyethyl cellulose was finally determined through the experimental results.

The properties of the prepared high-viscosity hydroxyethyl cellulose were analyzed and tested, including the determination of viscosity, ash content, light transmittance, moisture content, etc., through infrared spectroscopy, nuclear magnetic resonance, gas chromatography, X-ray diffraction, Thermogravimetric-differential thermal analysis and other characterization methods are used to analyze and characterize the product’s structure, substituent uniformity, molar substitution degree, crystallinity, thermal stability, etc. The test methods refer to ASTM standards.

Hydroxyethyl cellulose, an important cellulose derivative, has attracted attention due to its abundant raw material resources, renewable, biodegradable, nontoxic, biocompatible, and high yield. The viscosity of hydroxyethyl cellulose is a very important indicator of its performance. The viscosity of the prepared hydroxyethyl cellulose is above 5×104mPa·s, and the ash content is less than 0.3%.

In this paper, high-viscosity hydroxyethyl cellulose was prepared by liquid-phase synthesis method through alkalization and etherification. The alkalization process is the preparation of alkali cellulose. Choose from two alkalization methods. One is that the cellulose material is directly alkalized with acetone as a diluent in an aqueous sodium hydroxide solution, and then undergoes an etherification reaction with an etherifying agent. The other is that the cellulosic material is alkalized in aqueous sodium hydroxide solution and urea. The excess alkali in the alkali cellulose must be removed before the reaction. In this paper, various alkali celluloses are studied by infrared spectroscopy and X-ray diffraction. Finally, the second method is adopted according to the properties of etherification products.

In order to determine the preparation steps of etherification, the reaction mechanism of antioxidant, alkali and glacial acetic acid in the process of eating was studied. The factors affecting the preparation of hydroxyethyl cellulose were determined by single factor experiment. Based on the viscosity value of the product in 2% aqueous solution. The experimental results show that the volume of diluent, the amount of ethylene oxide, the alkalization time, the temperature and time of the first and second rehydration have great influence on the product performance. The method of seven factors and three levels was adopted to determine the best preparation method.

We analyze the properties of the prepared hydroxyethyl cellulose, including viscosity, ash, light transmittance, moisture, etc. The structural characterization, substituent homogeneity, substitution molarity, crystallinity and thermal stability were discussed by infrared, nuclear magnetic resonance, gas chromatography, X-ray diffraction, DSC and DAT, and the test methods adopted ASTM standards.