复旦大学：《有机化学实验 Organic chemistry lab》课程教学资源（实验讲义）Synthesis of ethyl benzoate

E Organic Chemistry Experiment Synthesis of ethyl benzoate Experimental Center for Chemical Education of Fudan University 三画日

Synthesis of ethyl benzoate Organic Chemistry Experiment Experimental Center for Chemical Education of Fudan University

月 Experimental Purpose 1. Understand the mechanism of esterification 2. Learn to use the oil-water separator 3. Master basic operations such as extraction drying, and distillation

Experimental Purpose 1. Understand the mechanism of esterification 2. Learn to use the oil-water separator 3. Master basic operations such as extraction, drying, and distillation

E Experimental Background Esterification is a common type of organic chemical reaction It is the reaction between alcohol and carboxylic acid or oxygen-containing inorganic acid to form ester and water The esterification reaction between carboxylic acid and alcohol is reversible, and the reaction is generally very slow Therefore concentrated sulfuric acid is often used as a catalyst, and the operation with water can be used to promote the reaction process

Experimental Background Esterification is a common type of organic chemical reaction. It is the reaction between alcohol and carboxylic acid or oxygen-containing inorganic acid to form ester and water. The esterification reaction between carboxylic acid and alcohol is reversible, and the reaction is generally very slow. Therefore, concentrated sulfuric acid is often used as a catalyst, and the operation with water can be used to promote the reaction process

)2 Experimental Mechanism H2so H2o H H H ⑨

Experimental Mechanism

月 Physical constant Benzoic acid fw 122 12 mp 122-123C Ethanol FW4607 bp 78oC d0789 n2013600 Ethyl Benzoate FW15018 bp 212C d 1.051 np 1.5068

Physical Constant

)2 Experimental Device x A△ Synthesis device Purification Device

Experimental Device Synthesis Device Purification Device

2 Synthetic Procedures 1. The device was set up as drawn and cyclohexane (5 mL) was added from the upper end of the oil-water separator. Benzoic acid(8.0 g), 95% ethanol (18mL) cyclohexane(15mL)and concentrated sulfuric acid (3 mL) was refluxed until that there were almost no drops of water. The water was discharged and continue heating until most of the ethanol and cyclohexane are distilled into the oil-water separator 2. The resulting mixture was put into cold water. Sodium carbonate was added to adjust the ph to 7 3. The aqueous layer was extracted with ether (20mL) and combined with the product layer. The organic phase was dried over anhydrous magnesium sulfate for 0.5h 4. Evaporate the ether Then use an air bath to heat the temperature to 140 C Replace the straight condenser with an air condenser and collect the 210-213 C fraction

Synthetic Procedures 1. The device was set up as drawn and cyclohexane (5 mL) was added from the upper end of the oil-water separator. Benzoic acid (8.0 g), 95% ethanol (18mL), cyclohexane (15mL) and concentrated sulfuric acid (3 mL) was refluxed until that there were almost no drops of water. The water was discharged and continue heating until most of the ethanol and cyclohexane are distilled into the oil-water separator. 2. The resulting mixture was put into cold water. Sodium carbonate was added to adjust the pH to 7. 3. The aqueous layer was extracted with ether (20mL) and combined with the product layer. The organic phase was dried over anhydrous magnesium sulfate for 0.5 h. 4. Evaporate the ether. Then use an air bath to heat the temperature to 140 ℃. Replace the straight condenser with an air condenser, and collect the 210-213 ℃ fraction

2 Attention 1. When heating to reflux, start the reflux slowly 2. When adding sodium carbonate powder to neutralize the acid, slowly add and stir 3. When distilling diethyl ether, avoid open flames, and connect a rubber tube to the drain pipe at the end of the pipe

Attention 1. When heating to reflux, start the reflux slowly！ 2. When adding sodium carbonate powder to neutralize the acid, slowly add and stir！ 3. When distilling diethyl ether, avoid open flames, and connect a rubber tube to the drain pipe at the end of the pipe！