How does aspirin react with NaOH?

This article talks about the aspirin reaction with NaOH, its details, and related concepts with complete theoretical explanations.

Introduction:

Aspirin (2-acetoxybenzoic acid or acetylsalicylic acid) is one of the most common medications & chemical compounds found in any medical pharmacy or over-the-counter station. It has been a standard clinical pain reliever and fever reducer for more than a century. It has a white crystalline appearance belonging to nonsteroidal anti-inflammatory drugs (NSAIDs) and has a chemical formula of C₉H₈O₄.

It is chemically derived from salicylic acid, which is a benzoic acid. It is commonly prepared from acetic anhydride and salicylic acid. To be chemically specific, it is benzoic acid with its acylated alcohol function replaced in the ortho position (carboxylic acid is the first substituent in this molecule and the second is an ester group).

Medical Significance of Aspirin:

Aspirin is used to treat fever and mild to moderate pain from ailments such as headaches, toothaches, stomachaches, and persistent colds. This drug can be utilized to lessen pain and inflammation in ailments like arthritis. It also works great against cold and flu symptoms. Doctors also recommend this drug for managing pain after surgical and dental procedures as it also has pain-relieving properties (not a very strong ability but it is still there).

Aspirin is also a great anticoagulant. It has similar working as compared to heparin or warfarin, all of which slow down the process of clotting in our bodies. Aspirin can stop platelets or blood cells from clumping together to create clots. Modified versions of aspirin are used to treat stroke victims and lessen their chance of dying while undergoing a heart attack.

Aspirin Reaction with NaOH

The reaction between aspirin and a strong base like NaOH falls under the category of saponification reactions. It involves the hydrolysis of esters in the presence of a base. This hydrolysis results in the formation of an alcohol along with carboxylate salts.

The reaction between aspirin and NaOH yields ethanol (alcohol) and an aqueous sodium acetylsalicylate (aspirin sodium C₉H7NaO₄). This reaction is not relevant to any medical application of this drug but is more of a laboratory experiment. This reaction can also be termed saponification which is a kind of hydrolysis reaction.

C₉H₈O₄ + NaOH   → C₉H₇O₄Na + H₂O

Aspirin Reaction with NaOH can happen in two scenarios; one is the faster reaction which involves the deprotonation of the acidic proton in the carboxyl group resulting in sodium acetylsalicylate and water as shown above. The second scenario (which is less common) can result in a slower reaction involving saponification of ethyl function in acetylsalicylic acid from aspirin.

 C₉H₈O₄ + NaOH → C₇H₅H₃Na + C₂H₂O₂Na + H₂O

The acetyl function's saponification is the other. This is an ester function. It is the salicylate ester of acetic acid in the case of aspirin. The common term for 2-hydroxy-benzoic acid is salicylate. Therefore, sodium acetate and sodium salicylate are produced when the acetyl is saponified.

The first reaction can happen at room temperature in normal temperature settings in a laboratory while the second one requires external heating. Moreover, the first one requires little reaction time to commence while the second one is much time and takes more to complete.

When aspirin is allowed to dissolve in water, it experiences complete dissolution as water is a polar solvent and aspirin is a polar molecule as well with hydrophobic and hydrophilic parts in it. The polar parts undergo dissolution and let aspirin completely dissolve. The aspirin and water reaction is as follows:

C₉H₈O₄ + H₂O → C₉H₇O₄ + H₃O⁺

Significance and Implications:

The salt produced from this reaction; the Sodium acetylsalicylate is much more water soluble as compared to the acetylsalicylate itself. This property makes it very useful in many pharmaceutical production processes where the bioavailability of the compound is crucial. This reaction and its products are also used in industrial processes where pH stability is required and strict optimization is needed for certain food productions. 

Wrapping Up:

Aspirin is one of the most common drugs available to date. This drug blocks prostaglandins which are responsible for feeling pain, inflammation, and fever in our bodies. Moreover, aspirin can lower the risk of strokes and heart attack and improves blood flow to the heart and brain by preventing platelets in your blood from constricting and clotting your arteries. Aspirin reaction with NaOH leads to two possible scenarios and different products. At room temperature, the first reaction happens quickly and the second scenario is slower, both result in different products.