Oxidation of Benzaldehyde by Use of Permanganate - Lab Report Example

Oxidation of Benzaldehyde by use of Permanganate

Introduction

The purpose of this experiment is to investigate the oxidizing properties of potassium permanganate on an aldehyde. Oxidation is a process that has found widespread applications in organic chemistry. Oxidation processes are mainly involved during the production of carbonyl compounds, which are often found in substances such as aldehydes and ketones. For instance, the oxidation process induced by the permanganate easily converts the primary alcohols into products such as aldehydes, and in other cases, also lead to the production of carboxylic acids. Similarly, the secondary alcohols may also be converted to ketones.

Oxidizing agents vary in capabilities, where some of them have the strengths of splitting alkenes into different groups of carboxylic acids. The oxidizing materials may also have the strength of oxidizing the side chains of the aromatic compounds to form carboxylic acids. Oxidation is also an important procedure that is widely use in industrial applications. For instance, the process may lead to the production of synthetic fibers, which are majorly formed using carbolic acids. The acids are usually produced though oxidation processes which involve the use of simple organic compounds. An example of this phenomenon may be seen in the commercial production of polyester where oxidation of simple raw materials leads to the formation of terephthalic acid. Similarly, during the industrial production of Nylon, the raw material used for the process is the cyclohexane, which first undergoes oxidation to produce cyclohexanone (Gibson, 2016).

The oxidation also additionally produces cyclohexanone before reacting further to produce Adipic acids. In spite of the effectiveness of the two processes, the presence of strong catalysts which will utilize oxygen from the air during the oxidation process of the starting compounds is required. To oxidize a substance while using the oxygen from the atmosphere, the process requires high amounts of pressures. Hence, the investigation of oxidation process as per normal laboratory standards would prove to not only to be difficult to achieve, but also a dangerous exercise. Due to this, the presence of oxygen atoms within the chemical structure of the oxidizing agents is required when performing the laboratory experimentations. In organic chemistry, 2 of the most popular oxidizing compounds that have found the widest applications when conducting the laboratory experiments include Potassium Permanganate and the different compounds of chromium(VI) Oxide. Each of the two agents are highly reactive and are utilized for a wide range of oxidation applications.

For this experiment, the Potassium permanganate is the choice oxidizing agent used to convert the benzaldehyde compound into benzoic acid. The theory of the oxidization action entails the use of an ester group of the compound. The chemical reaction may not only be conducted in both basic and acidic states, but can also be performed in neutral conditions.

Procedure

To set up the procedure, a water sample (300 milliliter) that has been deionized is added into a beaker of about 200 milliliters. The water in the beaker is then boiled by immersing an electric heater into it. A 0.2 milliliter sample of benzaldehyde is then added into a vial with the aid of a glass pipette. From the 0.3 Molar of potassium permanganate, a sample of 6.5 milliliter is obtained. The obtained sample is then added into the vial. Using the drop bottle, four drops are then added in to the mixture from the 1 molar NaOH solution. The reaction container is then tightly sealed using a cap. The vial is then shaken until the purple colored appearance of the mixture starts changing to brown to mark the change of the MnO4 to MnO2. The sealed container is then positioned by means of a pair of tongs into the beaker having the heated water. The reaction should be monitored for 20 min after which the vial should be allowed to cool. A water bath with ice should then be made ready.

To isolate the produced compound, the vial is then left for 3 minutes while placed in the ice water. The solution should then be tested for the presence of any unreacted potassium permanganate. To determine this, a glass rod is inserted into the solution and then used to touch a filter paper (Ratnani, 2012). If a trace of pink color can be seen around the brown color of the spot, then this should be treated as a case of surplus permanganate. From the sodium sulfite solution, 2 -3 drops are obtained, before being added into the mixture to react with the excessive permanganate. The solution is then retested.

The Buchner funnel is then utilized to perform a vacuum filtration of the sodium benzoate from the brown residue that is manganese dioxide. The residue is then washed with warm water before being disposed of. The filtrate is then added into a test tube. Two drops are then obtained from the Sodium sulfite sample, and this is then added into the filtrate. A 2 milliliter sample of 1 molar HCl is then added to the Sodium Benzoate up to a point at which the pH of 1 is obtained. A precipitate should then start to form. The solution is then cooled in the ice water in order to enhance the formation of the benzoic acid. The produce is then isolated through the use of vacuum filtration. After being cleaned using 2 milliliter of water, the isolated produce is vacuum dried and set on the bench to dry.

Observations and Results

Error Analysis

Some of the possible causes of errors in this experiment could have been caused by human error. However, the theoretical expectations of the experiment matched the outcome of the practical. For instance, the changes in the color of the solution from purple to yellow were observed to mark the reduction of the sodium permanganate. Furthermore, the addition of sodium sulfite solution to the mixture clarified it as expected. Finally, the precipitate formation was also observed.

Discussion

Besides permanganate, there are some alternative organic chemicals that may be used in the creation of Benzoic acid. For instance, these include the oxidation of methylbenzene, which is normally applied in industrial productions. The other methods can include the use of benzyl alcohol and also by using benzyl chloride.

When producing sodium benzoate solution, it is important to ensure that no trace of permanganate is left. The reason for this is that it will lead to a Redox reaction once the hydrochloric acid intended to initiate the precipitation is added. Furthermore, it ensures that the filtrate is not contaminated with potassium permanganate.

Potassium permanganate has been identified to be a strong oxidizing agent that has the capability of oxidizing strong carbonic bonds. However, during this experiment, the benzene rings have not been affected because Potassium permanganate is not a strong oxidizing agent for alcohols, and the fact that the experiment is conducted in basic solution has also ensured that the strong oxidizing properties are limited.

In this procedure, the basic conditions have been preferred due to the fact that it facilitates an easy removal of the Sodium Benzoate that is formed through filtration since the compound dissolves in the solution of the mixture. Hence, this helps to separate it from Manganese Dioxide, which is insoluble (Hafner, Lehn & Rees, 2012). Consequently, the filtered product is acidified, which leads to production of satisfactory quantities of benzoic acid. The other reason for conducting the oxidation in basic conditions is due to the fact that in acidic condition, there results in very strong oxidization property of potassium permanganate. However, when used in basic conditions, only partial oxidization is achieved, hence ensuring that the carbon double bonds are not affected.

Some of the commercial products that contain benzoic acid include metal polish and tooth paste. On the other hand, products containing Sodium benzoate include vinegar and fruit juices.

Conclusion

In conclusion, potassium permanganate is an excellent oxidizing agent that can be used in the production of various products. For instance, benzoate acid can be cheaply produced in high yields under the laboratory conditions by using the oxidizing properties of potassium permanganate.