Abstract: Acetanilide is the raw material of sulfonamides, which can be used as analgesics, antipyretics and preservatives. Used to make dye intermediates p-nitroacetanilide, p-nitroaniline and p-phenylenediamine. During the Second World War, it was widely used to make acetaminophen sulfonyl chloride. Acetanilide is also used to make thioacetamide. In industry, it can be used as rubber vulcanization accelerator, fiber fat coating stabilizer, hydrogen peroxide stabilizer and for synthesizing camphor. Health hazard: inhalation is irritating to upper respiratory tract. High dose intake can cause methemoglobinemia and bone marrow hyperplasia. Cyanosis will appear after repeated contact. Irritate the skin and cause dermatitis. Can inhibit the central nervous system and cardiovascular system, and a large number of contacts can cause dizziness and pallor. Acetanilide was synthesized from aniline, acetic anhydride and acetic acid. The effects of acetic anhydride dosage, acetic acid dosage and reaction time on the yield of acetanilide were investigated. The optimum technological conditions were determined: n (aniline): n (acetic acid): n (acetic anhydride) = 1:2.0:0.2, and the reaction time was 4.5 h. Under these conditions, the yield of acetanilide was 98.2% ~ 98.4%, and the purity was 99.58% ~ 99.82%. Key words: synthesis of acetanilide, aniline, acetic anhydride and acetic acid Preface: molecular formula: molecular weight 135 5438+0652 CASNo. 103-84-4 white shiny flaky crystals or white crystalline powder. Flammable. Tasteless. Stable and neutral in air. The relative density is1.2190 (15/4℃). The melting point is 1 14.3℃. The boiling point is 304℃. Flash point 173.9℃. The autoignition point is 546℃. Slightly soluble in cold water, soluble in hot water, methanol, ethanol, ether, chloroform, acetone, glycerol and benzene. Uses: The toxicity of dyes and pharmaceutical intermediates enters the body from the respiratory system and digestive system, which can inhibit the central nervous system and cardiovascular system. A lot of contact can cause dizziness and pallor. The oral LD50 of rats was 800 mg/kg. Production equipment should be sealed. Operators should wear protective equipment to avoid direct contact. Take a bath with warm water after work. Packaging, storage and transportation are packed in inner plastic bags, outer gunny bags or canvas bags, each with a net weight of 50 kg. Store in a cool, dry and ventilated place to prevent fire and moisture. It can be transported by car or train. Toxic chemicals are stored and transported according to regulations. 1. experimental purpose 1. Master the preparation principle and method of acetanilide 2. Further study the operation method of solid recrystallization and purification Keywords: recrystallization of acetanilide, thermal filtration of glacial acetic acid, practical difficulties in organic chemistry: synthesis principle and method of acetanilide II. Experimental principle acetanilide can be prepared by the reaction of aniline with acylating agents such as acetyl chloride, acetic anhydride or glacial acetic acid. Acetyl chloride and acetic anhydride react with aniline too violently, which is not suitable for laboratory use, while glacial acetic acid reacts with aniline smoothly, easily controlled and with the lowest price, so glacial acetic acid is used as acylating reagent in this experiment. The reaction formula is reversible and the yield is low. In order to reduce the occurrence of reverse reaction and obtain higher yield, the amount of acetic acid can be added. In addition, the temperature at the top of the tower is controlled at 105- 1 10 by fractional distillation, and the balance is effectively moved to the positive reaction direction by continuously discharging the generated water. Because aniline is easy to be oxidized, a small amount of zinc powder is added during the reaction to prevent aniline from being oxidized. Pure acetanilide is a white flaky crystal with a melting point of 1 14. It is slightly soluble in hot water, ethanol, ether, chloroform, acetone and other solvents, but hardly soluble in cold water, and can be recrystallized with hot water. 3. Experimental articles 1. Instruments: 50 ml round bottom flask, 50 ml conical flask, beaker, fractionator, hot bath funnel, 150℃ thermometer and a set of suction filtration device. 1. Drugs: aniline, glacial acetic acid, zinc powder, activated carbon 3. Experimental setup Figure 4. Physical constants: aniline: density 1.022g/ml, boiling point 184OC acetic acid: density 1.05g/ml, boiling point18ociv. A fractionating tower was installed in the round bottom flask, a thermometer at 150℃ was installed at the top of the tower, and a fractionating device was installed. Heat the round-bottomed flask with an electric heating jacket and keep the temperature between 100- 1 10℃ for about 60 minutes. When the water and part of acetic acid produced by the reaction are distilled off, the thermometer reading will drop, indicating that the reaction has been completed and heating can be stopped. While stirring, the reactants were poured into 100ml cold water, and after the reaction was cooled to separate out crystals, they were filtered and washed with cold water to obtain crude acetanilide. 2. Refinement of crude acetanilide. Boil the obtained crude acetanilide with 50 ml of water. When the oil is completely dissolved (if it cannot be completely dissolved, add an appropriate amount of water and record the volume of water added), stop heating, add 0. 1g activated carbon after cooling slightly, stir, continue to boil for 5- 10min for decolorization, filter while it is hot, and a large number of crystals will precipitate after cooling the filtrate, and then filter. Weigh and calculate the output. V. Precautions 1. The glass instrument used in the reaction must be dry. 2, the role of zinc powder is to prevent aniline oxidation, as long as a small amount. If too much is added, water-insoluble zinc hydroxide will appear. 3. The fractionation temperature should not be too high during the reaction to avoid evaporation of a large amount of acetic acid and reduce the yield. 4. During recrystallization, crystals may not precipitate. You can rub the beaker wall with a glass rod, or add seeds to precipitate the crystals. 5. Glacial acetic acid is highly irritating and should be taken in a fume hood. 6, shall not be added to the boiling solution of activated carbon, so as not to cause boiling. Intransitive verb note 1. Aniline stored for a long time should be redistilled before use because of its dark oxidation color. Because of the high boiling point of aniline, air condenser is used for condensation and vacuum distillation is used for distillation. 2. If the reaction solution is allowed to cool Abstract: Acetanilide is the raw material of sulfonamides, which can be used as analgesics, antipyretics and preservatives. Used to make dye intermediates p-nitroacetanilide, p-nitroaniline and p-phenylenediamine. During the Second World War, it was widely used to make acetaminophen sulfonyl chloride. Acetanilide is also used to make thioacetamide. In industry, it can be used as rubber vulcanization accelerator, fiber fat coating stabilizer, hydrogen peroxide stabilizer and for synthesizing camphor. Health hazard: inhalation is irritating to upper respiratory tract. High dose intake can cause methemoglobinemia and bone marrow hyperplasia. Cyanosis will appear after repeated contact. Irritate the skin and cause dermatitis. Can inhibit the central nervous system and cardiovascular system, and a large number of contacts can cause dizziness and pallor. Acetanilide was synthesized from aniline, acetic anhydride and acetic acid. The effects of acetic anhydride dosage, acetic acid dosage and reaction time on the yield of acetanilide were investigated. The optimum technological conditions were determined: n (aniline): n (acetic acid): n (acetic anhydride) = 1:2.0:0.2, and the reaction time was 4.5 h. Under these conditions, the yield of acetanilide was 98.2% ~ 98.4%, and the purity was 99.58% ~ 99.82%. Key words: synthesis of acetanilide, aniline, acetic anhydride and acetic acid Preface: molecular formula: molecular weight 135 5438+0652 CASNo. 103-84-4 white shiny flaky crystals or white crystalline powder. Flammable. Tasteless. Stable and neutral in air. The relative density is1.2190 (15/4℃). The melting point is 1 14.3℃. The boiling point is 304℃. Flash point 173.9℃. The autoignition point is 546℃. Slightly soluble in cold water, soluble in hot water, methanol, ethanol, ether, chloroform, acetone, glycerol and benzene. Uses: The toxicity of dyes and pharmaceutical intermediates enters the body from the respiratory system and digestive system, which can inhibit the central nervous system and cardiovascular system. A lot of contact can cause dizziness and pallor. The oral LD50 of rats was 800 mg/kg. Production equipment should be sealed. Operators should wear protective equipment to avoid direct contact. Take a bath with warm water after work. Packaging, storage and transportation are packed in inner plastic bags, outer gunny bags or canvas bags, each with a net weight of 50 kg. Store in a cool, dry and ventilated place to prevent fire and moisture. It can be transported by car or train. Toxic chemicals are stored and transported according to regulations. 1. experimental purpose 1. Master the preparation principle and method of acetanilide 2. Further study the operation method of solid recrystallization and purification Keywords: recrystallization of acetanilide, thermal filtration of glacial acetic acid, practical difficulties in organic chemistry: synthesis principle and method of acetanilide II. Experimental principle acetanilide can be prepared by the reaction of aniline with acylating agents such as acetyl chloride, acetic anhydride or glacial acetic acid. Acetyl chloride and acetic anhydride react with aniline too violently, which is not suitable for laboratory use, while glacial acetic acid reacts with aniline smoothly, easily controlled and with the lowest price, so glacial acetic acid is used as acylating reagent in this experiment. The reaction formula is reversible and the yield is low. In order to reduce the occurrence of reverse reaction and obtain higher yield, the amount of acetic acid can be added. In addition, the temperature at the top of the tower is controlled at 105- 1 10 by fractional distillation, and the balance is effectively moved to the positive reaction direction by continuously discharging the generated water. Because aniline is easy to be oxidized, a small amount of zinc powder is added during the reaction to prevent aniline from being oxidized. Pure acetanilide is a white flaky crystal with a melting point of 1 14. It is slightly soluble in hot water, ethanol, ether, chloroform, acetone and other solvents, but hardly soluble in cold water, and can be recrystallized with hot water. 3. Experimental articles 1. Instruments: 50 ml round bottom flask, 50 ml conical flask, beaker, fractionator, hot bath funnel, 150℃ thermometer and a set of suction filtration device. 1. Drugs: aniline, glacial acetic acid, zinc powder, activated carbon 3. Experimental setup Figure 4. Physical constants: aniline: density 1.022g/ml, boiling point 184OC acetic acid: density 1.05g/ml, boiling point18ociv. A fractionating tower was installed in the round bottom flask, a thermometer at 150℃ was installed at the top of the tower, and a fractionating device was installed. Heat the round-bottomed flask with an electric heating jacket and keep the temperature between 100- 1 10℃ for about 60 minutes. When the water and part of acetic acid produced by the reaction are distilled off, the thermometer reading will drop, indicating that the reaction has been completed and heating can be stopped. While stirring, the reactants were poured into 100ml cold water, and after the reaction was cooled to separate out crystals, they were filtered and washed with cold water to obtain crude acetanilide. 2. Refinement of crude acetanilide. Boil the obtained crude acetanilide with 50 ml of water. When the oil is completely dissolved (if it cannot be completely dissolved, add an appropriate amount of water and record the volume of water added), stop heating, add 0. 1g activated carbon after cooling slightly, stir, continue to boil for 5- 10min for decolorization, filter while it is hot, and a large number of crystals will precipitate after cooling the filtrate, and then filter. Weigh and calculate the output. V. Precautions 1. The glass instrument used in the reaction must be dry. 2, the role of zinc powder is to prevent aniline oxidation, as long as a small amount. If too much is added, water-insoluble zinc hydroxide will appear. 3. The fractionation temperature should not be too high during the reaction to avoid evaporation of a large amount of acetic acid and reduce the yield. 4. During recrystallization, crystals may not precipitate. You can rub the beaker wall with a glass rod, or add seeds to precipitate the crystals. 5. Glacial acetic acid is highly irritating and should be taken in a fume hood. 6, shall not be added to the boiling solution of activated carbon, so as not to cause boiling. Intransitive verb note 1. Aniline stored for a long time should be redistilled before use because of its dark oxidation color. Because of the high boiling point of aniline, air condenser is used for condensation and vacuum distillation is used for distillation. 2. If the reaction solution is allowed to cool, solid acetanilide will precipitate and stick to the flask wall, so it is not easy to pour out. 3. When filtering while it is hot, you can also use the suction filter. But the Buchner funnel and suction bottle must be preheated. The size of the filter paper should be appropriate, and the filtration process should be fast to avoid the crystallization of the product in the Buchner funnel. However, solid acetanilide has precipitation, which is not easy to pour out because it sticks to the flask wall. 3. When filtering while it is hot, you can also use the suction filter. But the Buchner funnel and suction bottle must be preheated. The size of the filter paper should be appropriate, and the filtration process should be fast to avoid the crystallization of the product in the Buchner funnel.