My procedure
Measure out 3.81 g (25.0 mmol) of Vanillin into a 25 mL round-bottom flask. Add 5 mL of ethanol, stirring the flask to dissolve the vanillin. If it does not dissolve entirely, add up to another 5 mL ethanol.
Set up a ring stand holding a dropping funnel with the flask beneath it. Ensure that there is a gap between the funnel and the flask, or use a t-connector with one open end. This is to ensure an open system during the reaction.
Measure out 0.47 g (12.5 mmol) of Sodium Borohydride into a flask. Add 10 mL of Ethanol, ensure that the NaBH4 dissolves. Pour the NaBH4 solution into the dropping funnel.
Using a thermometer to measure the temperature of the solution while the reaction takes place. While stirring, add the NaBH4 solution dropwise to the Vanillin solution slowly, ensuring that the reaction temperature stays below 25 °C. If the temperature rises too quickly, place the flask in an ice bath.
After the NaBH4 has been completely added, continue to stir the solution for ten minutes, monitoring the temperature.
Under the hood, add 3M HCl dropwise to the solution, testing with pH paper until the pH of the solution is £ 6. Keep away from flames, as Hydrogen gas will be released. When the solution is suitably acidic, cool it in an ice bath.
Collect the precipitate by vacuum filtration. Use cold water to wash the product.
Allow the product to dry to constant mass (may take a few days), and measure the melting point.