Taking bacterial cellulose as raw materials, synthesize 2-hydroxy-3-sulfate propyate cellulose ether. The infrared spectrometer analyzes the product structure. Best process conditions for synthesis of base bacterial cellulose ether. The results showed that the exchange capacity of 2-hydroxy-3-sulfonic acid-based propyate bacterial ether synthesized under optimization conditions was 0.481mmol / g.
Keywords: bacterial cellulose; 2-hydroxyl-3-sulfonic acid-based gornemine cellulose ether; exchange capacity
Microbial synthetic bacterial cellulose is similar to plant cellulose in chemical composition and molecular structure. It is a straight polysaccharide connected by D-pyrarot glucose with β-1, 4-glycoside bonds. Compared with plant cellulose, bacterial cellulose has a better characteristic. It is an ultra -micro fiber net composed of ultra -micro fibers. It exists in the form of pure cellulose and has many unique functions. The aspects of acoustic equipment and oil mining have been widely used.
2-hydroxyl-3-sulfonate cellular cellulose ether is an important cellulose derivative that can be made of high water absorption materials. It can also be used as a solid purity for adsorption of heavy metal ions and protein as a cation. Feng Qingqin, Jie Zhefeng and other cellulose used in rice shell corn straw to prepare 2-hydroxyl-3-sulfate cellulose ether strong acid cationic exchanges. This article uses bacterial cellulose as raw materials, synthesizing 2-hydroxyl-3-sulfonic acid-based bacterial cellulose ether, and uses orthogonal experiments to study its best synthetic conditions and 2-hydroxyl-3-sulfa-sulfa sulfa prepared under this condition. The exchanging capacity of acid -based gornemine cellulose ether provides theoretical basis for the actual application of the material.
1. Experimental part
1.1 Reagents and instruments
Bacterial cellulose (self-made), sodium hydroxide, sodium carbonate, sodium bisulfite, dioxane, epichlorohydrin, acetone, ethanol, sodium carbonate, the above reagents are of analytical grade.
Incubator/drying box (Shanghai-Heng Technology Co., Ltd.); GQF-1 jet mill (Powder Center, Nanjing University of Science and Technology); Fourier infrared spectrometer (Germany); Agilent AAS-3510 atomic absorption spectrophotometer.
1.2 Preparation of 2-hydroxy-3-sulfopropyl bacterial cellulose ether
1.2.1 Synthesis of cross-linked bacterial cellulose
Add 10g of bacterial cellulose powder, 60mL of epichlorohydrin and 125mL of 2mol·L-1 NaOH solution into a three-necked flask equipped with a reflux condenser and a stirrer, heat to reflux for 1h, filter, and cross-wash with acetone and water to medium properties, and dried under vacuum at 60°C to obtain cross-linked bacterial cellulose.
1.2.2 Synthesis of sodium 3-chloro-2 hydroxypropanesulfonate
Weigh 104.0gNaHSO3 and dissolve it in 200mLH2O, and let it be saturated with SO2 gas. Heat up to 70-90°C with stirring, then add 160mL epichlorohydrin with a dropping funnel, and react at 85°C for 4h. The reaction product was cooled to below 5°C to crystallize the product, then suction filtered, washed, and dried to obtain a pale yellow crude product. The crude product was recrystallized with 1:1 ethanol to obtain white crystals.
1.2.3 Synthesis of 2-hydroxy-3-sulfopropyl bacterial cellulose ether
Add 2 g of cross-linked bacterial cellulose, a certain amount of 3-chloro-2-hydroxypropanesulfonate, 0.7 g of sodium carbonate, and 70 mL of dioxane aqueous solution into a three-necked flask equipped with a reflux condenser and a stirrer, nitrogen Under protection, control a certain temperature and stir to react for a certain period of time, filter, wash with acetone and water in turn to neutrality, and vacuum-dry at 60°C to obtain a light yellow solid.
1.3 Product structure analysis
FT-IR test: solid KBr tablet, test range: 500cm-1～4000cm-1.
1.4 Determination of exchange capacity
Take 1-2g of 2-hydroxy-3-sulfopropyl bacterial cellulose ether, add appropriate amount of distilled water to soak, then pour it into the exchange column with stirring, rinse with appropriate amount of distilled water, and then use about 100mL 5% Hydrochloric acid rinse, control the flow rate of 3mL per minute. Then wash with distilled water until it does not show acidity when tested by methyl orange, then elute with about 60mL of sodium chloride with a concentration of 1mol L-1, control the flow rate at about 3mL/min, and collect the effluent with an Erlenmeyer flask. Then wash the column with 50-80mL distilled water. The collected solution was titrated with 0.1mol·L-1 sodium hydroxide standard solution using phenolphthalein as indicator, and the number of milliliters of sodium hydroxide consumed was VNaOH.
2. Results and discussion
2.1 Structural characterization of cross-linked bacterial cellulose
Due to the introduction of new C—H, the cross-linked bacterial cellulose is 2922.98cm-1. The stretching vibration of C—H on the sugar ring is enhanced, and the characteristic absorption peaks of the hydroxyl groups at 1161.76cm-1 and 1061.58cm-1 of the spectral line a are weakened, which are the characteristic absorption peaks of hydroxyl groups in cellulose. At 3433.2cm-1, the vibrational absorption peak of the associated hydroxyl group still exists, but the relative intensity decreases, indicating that the hydroxyl group on the glucoside ring has not been completely substituted.
2.2 Structural characterization of sodium 3-chloro-2-hydroxypropanesulfonate
3525～3481cm-1 is the stretching vibration of association hydroxyl O—H bond, 2930.96cm-1 is the asymmetric stretching vibration of C—H, 2852.69cm is the symmetrical stretching vibration of C—H, 1227.3cm-1, 1054. 95cm-1 is the stretching vibration of S=O, 810.1cm-1 is the stretching vibration of C-O-S, and 727.4cm-1 is the stretching vibration of C—Cl, indicating that the target product is formed.
2.3 Structural characterization of 2-hydroxy-3-sulfopropyl bacterial cellulose ether
3431cm-1 is the O-H stretching vibration peak, 2917cm-1 is the saturated C-H stretching vibration peak, 1656cm-1 is the C-C stretching vibration peak, 1212~1020cm-1 is -SO2-antisymmetric and symmetric stretching vibration, 658cm-1 is the S-O bond stretching vibration.
2.4 Optimization of synthesis conditions for 2-hydroxy-3-sulfopropyl bacterial cellulose ether
In the experiment, the exchange capacity was used to test the quality of 2-hydroxy-3-sulfopropyl bacterial cellulose ether. The amount of 3-chloro-2 hydroxypropanesulfonate sodium added in the reaction, the concentration of dioxane aqueous solution, the reaction time and the temperature have done four factors and three levels of orthogonal experiments to analyze the effect of each factor on the bacterial cellulose xanthate. Influence of ester properties.
Orthogonal experiments show that the optimal combination of 4 factors is A2B1C3D. 1 Range analysis shows that the reaction temperature has the greatest influence on the adsorption performance of 2-hydroxy-3-sulfopropyl cellulose ether, and the range is 1. 914, followed by the concentration of time, dioxane, and the feeding amount of 3-chloro-2 hydroxypropanesulfonate sodium. The exchange capacity of 2-hydroxy-3-sulfopropyl bacterial cellulose ether prepared under optimized conditions was 0.481mmol/g, which was higher than that of similar SE-type cellulose strong acid cation exchange trees reported in the manual.
3. Conclusion
By modifying bacterial cellulose, 2-hydroxy-3-sulfonic acid propyl bacterial cellulose ether was synthesized, and its structure was characterized and its exchange capacity was measured. The following conclusions were drawn: 1) 2-hydroxy-3 – The optimal process conditions for the synthesis of sulfopropyl bacterial cellulose ether are: 2g cross-linked bacterial cellulose, 3.5g 3-chloro-2-hydroxypropanesulfonate sodium, 0.7g sodium carbonate and 7OmI30% dioxane Aqueous solution, reaction at 70°C under nitrogen protection for 1h, the 2-hydroxy-3-sulfonic acid propyl bacterial cellulose ether prepared under this condition has a higher exchange capacity; 2) 2-hydroxy-3-sulfonic acid group The exchange capacity of propyl bacterial cellulose ether is higher than that of the similar SE type cellulose strong acid cation exchange resin reported in the handbook.