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Instruments and pharmaceuticals: Round bottom flask (100mL), thorn-shaped fractionating column, a condenser straight wetted tube, cylinder (10mL), thermometer (200?), beaker (250mL), suction flask, Buchner funnel, small pumps, heat funnel , electric sets Aniline, glacial acetic acid, zinc powder, activated carbon Experimental Procedure 1. Acylation: In 100ml round bottom flask, add 5 ml of freshly distilled aniline, 8.5ml glacial acetic acid and 0.1g of zinc powder. Now fitted fractionating column, a thermometer was installed at the top of the column, with a small cylinder collect the distilled water and acetic acid. Experimental setup Refer to Figure 16-9. With electric sets slowly heated to boiling reactants. Regulated voltage, when the temperature rose to about 105 ?distillation begins. Maintaining the temperature at about 105? about 30min, then the reaction between the basic distilled water. When the thermometer readings declining, then the reaction to reach the end, you can stop heating. 2. Crystallization filtration: add 100ml water in a beaker, and the reaction solution was poured into hot water to thin stream, while keep stirring, this time with fine particulate solid precipitated. After cooling, filtration, and the solid was washed with a small amount of cold water to give the white or yellow crude N-Acetylaniline. 3. Recrystallization: The crude N-Acetylaniline was transferred to a beaker, add 100ml of water, heated to boiling under stirring. Observe whether there is undissolved oil, if the additional water until fully dissolved oil droplets. Coolish, add 0.5g of activated carbon, and boiled 10min. In the heat activated carbon was removed by hot filtration funnel. The filtrate was poured into a beaker of heat. Then cool to room temperature with ice water, waiting to be completely precipitated crystals for filtration. Cake was washed twice with a small amount of cold water, pressed dry. The crystals were transferred to the surface of the dish, dry naturally after weighing, and calculating yield. Considerations: (1)reaction glassware must be dry. (2)zinc's role is to prevent the oxidation of aniline, just a small amount can be. Add too much, there will be a water-insoluble zinc hydroxide. (3)fractionating the reaction temperature is not so high that a large number of distilling off the acetic acid and reduce the yield. (4)recrystallization, the crystal may not precipitated, the beaker wall friction can be a glass rod or seed crystals are added to precipitate crystals. (5)glacial acetic acid with a strong irritant to be drawn in a fume hood. (6)must not in a boiling solution of activated carbon was added, in order to avoid bumping. Frankie is the freelance writer for e-commerce website in the chemistry. Guidechem.com is just a place for you to look for some chemicals. Our guidechem provide the most convenient conditions for the international buyers and let these leads benefit all the business people. Guidechem chemical B2B network provides information on china and global chemical market quotation and relative chemical Information. Guidechem Chemical Network providing the most complete information of the chemical industry.
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