Making Bromobutane from Butan-1-ol - Practice Questions - PDF

Here is the text from the images converted into a markdown format: **16/02/25** ### Unit 3 ### Making Bromobutane from Butan-1-ol The image shows the chemical reaction of Butan-1-ol and HBr creating 1-Bromobutane and H2O. The reaction is expressed as: $H-C-C-C-C-OH + HBr \longrightarrow H-C-C-C-C...

Here is the text from the images converted into a markdown format: **16/02/25** ### Unit 3 ### Making Bromobutane from Butan-1-ol The image shows the chemical reaction of Butan-1-ol and HBr creating 1-Bromobutane and H2O. The reaction is expressed as: $H-C-C-C-C-OH + HBr \longrightarrow H-C-C-C-C -Br + H_2O$ ### How is HBr made?! 1. HBr is not found in lab as its unstable & decomposes $(H_2/Br)$. 2. It is made by reaction $H_2SO_4 + NaBr$ $H_2SO_4 + NaBr \longrightarrow NaHSO_4 + HBr$ (50% dilute) ### Why dilute $H_2SO_4$? If concentrated $H_2SO_4$ is used the HBr will oxidise into $Br_2$ $H Br \longrightarrow Br_2$ $H_2SO_4$ & $NaBr$ is highly exothermic so it's added dropwise into mixture while cooling. A large heat produced. \* or else mixture will boil & products will lost. The image shows a diagram of the experimental apparatus in the form of a round bottom flask in a water and ice bath. * $H_2SO_4$ added via tap funnel * $H_2O$ out * Heat under reflux * Butan-1-ol and $NaBr$ inside the round bottom flask Date: \* Once $H_2SO_4$ is added the mixture is heated under reflux (provides activation energy). Once the reflux is done many impurities left other than main product 1-bromo but one. ### Impurities a. Ionic compounds $[NaBr / NaHSO_4]$ b. Acidic compounds $[H_2SO_4 / NaBr]$ c. $H_2O$ MP x boil \* so to remove them distillation done The diagram shows a distillation apparatus consisting of a round bottom flask with a thermometer and a condenser and reciever * $H_2O$ in * Thermometer, H2O out * Round bottom flask contains mixture * Reciever contains aq & 1-bromabutane \* When Heat A When heating anti-bumping granules are added to make sure mixture won't form large bubbles. If large bubble formed the mixture will splash out so yield will low $ \downarrow Yield = \frac{actual \downarrow }{theoridical}$ \* Anti-bumping granules ensure smooth boiling. Date: \* Distillation removes the ionic impurities $[have IMP]$ \* The distillate that's collected in reciever contains 1-bromabutane and acidic $H_2O$. This added is added to a seperating funnel The image shows a separating funnel with two phases, * $H_2O [1g/cm^3]$ * Bromobutane \*Tap The aqueous layer is removed. \* 1 bromobutone still contains drops of $H_2O & acid$ How to remove acidic impurities?