This experiment is from the official website of Tianjin Agricultural College
Operation method
Experiments on the preparation of n-butyl ether Move Add 5.2 mL of n-butanol, 0.8 mL of concentrated sulfuric acid, and two grains of zeolite to a 50 mL two-necked flask, shake to mix well, and set up the device. The water distributor is filled with water to the stub and then 0.5 mL of water is released i.e. there is ( V-0.5 ) mL of water in the distributor. Begin to small fire heating, keep the liquid in the bottle slightly boiling, began to reflux, the temperature control in 134 ~ 135 ℃, to be the water distributor has been all filled with water when the reaction has been basically completed (about 1 hour), stop heating. Caveat 1. When adding, n-butanol and concentrated sulfuric acid are not fully shaken and mixed, the sulfuric acid is locally too concentrated, and it is easy to make the reaction solution turn black after heating. 2. According to the reaction formula, the amount of water generated is about 0.8 g, but the actual volume of water is slightly larger than the theoretical calculation, because there is a single molecule dehydration by-products generated. 3. This experiment utilizes the constant boiling mixture distillation method, using a water separator will be generated by the reaction of the water layer above the organic layer of continuous flow back to the reaction bottle, while the generated water is removed. In the reaction solution, n-butyl ether and water form a constant-boiling substance with a boiling point of 94.1 °C and 33.4 % water. n-Butanol and water formed a constant boiling substance with a boiling point of 93 °C and a water content of 45.5 %. n-Butyl ether and n-Butanol form a binary constant-boiling substance with a boiling point of 117.6 ℃ and a content of 82.5 % of n-Butanol. In addition, n-butyl ether can also form a ternary constant boiling substance with n-butanol and water, with a boiling point of 90.6 ℃, containing 34.6 % of n-butanol and 29.9 % of water. These water-containing constant-boiling substances are condensed and layered in the water separator. The upper layer is mainly n-butanol and n-butyl ether, and the lower layer is mainly water. The use of the water separator allows the organic matter in the upper layer of the separator to flow back into the reactor. 4. When the reaction starts to reflux, the temperature cannot reach 135 °C immediately because of the presence of the constant boiling material. However, as the water is vaporized, the temperature gradually rises, and finally reaches more than 135 ℃, that is, heating should be stopped. If the temperature rises too high, the reaction solution will be carbonized black, and a large number of by-products generated butene. 5. 50 % sulfuric acid preparation method: 20 mL of concentrated sulfuric acid is slowly added to 34 mL of water. 6. n-Butanol is soluble in 50 % sulfuric acid, while n-Butyl ether dissolves very little. For more product details, please visit Aladdin Scientific website.
After the reactants cooled down, the mixture together with the water in the water separator was poured into a dispensing funnel containing 7 mL of water, and shaken thoroughly.
After resting, the product crude n-butyl ether was separated and washed twice with 50% H2SO4 (3 mL x 2) and once with 5 mL of water. The organic layer was separated. Dry the product with anhydrous calcium chloride.
Pour the dried crude product into a round-bottomed flask for distillation (be careful not to pour calcium chloride into the flask!) , collect the fraction from 139 to 142 °C. Weigh the product, calculate the yield and determine the refractive index.