Benzoic acid is a common organic compound with the formula C6H5COOH. It is a white, crystalline solid that is used in a variety of applications, including as a food preservative, a pH adjuster in cosmetics, and a starting material for the synthesis of other chemicals. One method for preparing benzoic acid is through the oxidation of benzyl alcohol, which can be accomplished through the use of a number of different oxidizing agents.
In the laboratory, benzoic acid can be prepared by oxidation of benzyl alcohol using hydrogen peroxide as the oxidizing agent. The reaction can be carried out in the presence of an acid catalyst, such as sulfuric acid, to increase the rate of the reaction. The reaction can be carried out in aqueous solution, and the benzoic acid can be recovered from the reaction mixture by crystallization.
To perform the experiment, a solution of benzyl alcohol and sulfuric acid is prepared in a round-bottom flask. The flask is equipped with a reflux condenser and a magnetic stir bar, and the solution is heated to a temperature of about 50-60°C. A solution of hydrogen peroxide is then added slowly to the flask, and the reaction is allowed to proceed for a period of about 1-2 hours.
As the reaction proceeds, the benzyl alcohol is oxidized to benzoic acid, which forms white crystals in the reaction mixture. The reaction can be monitored using thin layer chromatography, which allows for the visualization of the reactants and products as the reaction progresses.
Once the reaction is complete, the benzoic acid crystals can be recovered by filtration and washed with cold water. The crystals can then be dried and weighed to determine the yield of the reaction. The purity of the benzoic acid can be determined by melting point analysis, which allows for the identification of impurities present in the crystals.
In conclusion, the preparation of benzoic acid from benzyl alcohol is a useful experiment for demonstrating the principles of oxidation and acid-catalyzed reactions. The yield and purity of the product can be determined through a variety of analytical techniques, allowing for the optimization of the reaction conditions and the development of efficient synthesis methods.
Benzoic acid preparation benzyl alcohol oxidation method
Results Observations - White flakes crystallization - Melting range: 92-97 degree C - Mass of filter paper: 0. Aim We aim to in this experiment to see if one of Magnesium, Magnesium Oxide, or Magnesium Carbonate can neutralise Hydrochloric Acid in an exothermic reaction to a PH of seven. Experiment 11 of Benzoic Acid, Experiments in General Chemistry, 4th ed. Ninhydrin is a powerful oxidizing agent which also known as triketohydrindene hydrate. This is seen in this experiment as a hydrogen on methyl benzoate is replaced with a nitronium ion. In addition to that, we use Na2O4 as a oxidizing agent. Although some vapors did escape, it was considerably less than in the first trial run.
Experiment 7
The reaction mixture is cooled in an ice bath. Third, some of the purified benzoic acid is redissolved in water and titrated against sodium hydroxide NaOH. By adding sodium carbonate, we will now test whether what obtained is benzoic acid or not, because one can observe bobbles if it is an acid. Then forming a hydrate that undergoes oxidation again by potassium permanganate, resulting in benzoic acid, the white crystals. Introduction Benzoic acid was first synthesized in the 16th century Oxidation Theory and Calculations In general, a primary alcohol can be oxidized to lend either aldehydes or carboxylic acids 2OH would be ethanol if R was CH 3. Also once the solution was finished refluxing, the solution was a brownish-orange colour and therefore the crystals were a dullish yellow colour versus being pure and white.
PREPARATION OF BENZOIC ACID
Residual benzyl alcohol is then rinsed down the condenser with a few millilitres of water and the reaction is allowed to continue until complete 10-15minutes. This document is the prior work of another student. First, it changed from dark purple to orange, then to light yellow, then to dark yellow, then burnt orange, and finally a brownish orange. The oxidation of primary alcohols to carboxylic acids is an important oxidation reaction in organic chemistry. This reaction provides an extremely sensitive test for amino acids. The average melting point for the first trial was 94 degrees Celsius, and 115 degrees Celsius for the second trial. In our particular experiment, we are oxidizing benzyl alcohol C 6H 5CH 2OH with permanganate MnO 4 -.
