Introduction

In the world of chemistry and medicine, there are several substances that have had a huge impact on our lives. One of these substances is acetylsalicylic acid, commonly known as aspirin. In 1853, chemist Charles Frederick Gerhardt first treated sodium salicylate with acetyl chloride to obtain acetylsalicylic acid. Since its discovery, aspirin has demonstrated its properties and has become an important part of the pharmaceutical industry.

In this article, we will start with an overview of the physical and chemical properties of acetylsalicylic acid, then the main reactions that reveal its chemical nature and applications.
Acetylsalicylic acid remains one of the most used drugs in medicine due to its action. It is used to reduce pain, antipyretic, prevent thrombosis and heart attacks and also as an anti-inflammatory agent.

Physical and Chemical Properties of Acetylsalicylic Acid

Acetylsalicylic acid (aspirin) is an acetic acid ester derivative of salicylic acid, with a chemical formula C9H8O4. It is odorless, small white needle-like crystals or light crystalline powder. Molecular weight of acetylsalicylic acid – 180.16 g/mol and a density 1.4 g/cm3 at 20°C. The melting point of this compound is 134-136 °C and the autoignition temperature 500°C. Acetylsalicylic acid is soluble in organic solvents such as ethanol (200 g/L at 20°C), diethyl ether (35,7 g/L at 20°C), chloroform (59 g/L at 20°C) and slightly soluble in water (3 g/L at 20°C).

Synthesis of Aspirin Lab

Synthesis of Acetylsalicylic Acid

One of the main methods of aspirin production is acetylation of salicylic acid. The process of acetylation occurs by replacing a hydroxyl group with an acetyl group, as a result, acetylsalicylic acid and acetic acid are formed. The reaction is carried out in the presence of an acid catalyst, most commonly a strong acid such as sulfuric acid or phosphoric acid are used.

A less common method for obtaining acetylsalicylic acid is the addition of hydrochloric acid to an aqueous solution of sodium acetylsalicylate. Acetylsalicylic acid is insoluble in water and precipitates as a white solid.

Chemical Properties of Acetylsalicylic Acid

Hydrolysis of acetylsalicylic acid

One of the fundamental chemical reactions of acetylsalicylic acid is hydrolysis. As a result of interaction with water, the acetyl group of aspirin decomposes with the formation of salicylic acid and acetic acid.

Reactions with alkalis

Acetylsalicylic acid reacts with alkaline hydrolysis to form acetylsalicylic acid. For example, the hydrolysis reaction of acetylsalicylic acid in the presence of sodium hydroxide solution.

Etherification of acetylsalicylic acid

Acetylsalicylic acid can participate in esterification reactions to form salicylic acid esters and acetates. For example, when acetylsalicylic acid reacts with methyl alcohol, methyl salicylate, methyl acetate and water are obtained.

Applications of Acetylsalicylic Acid

Acetylsalicylic acid is a key component of many medications designed to relieve pain, inflammation and fever. It is part of a combination of drugs for the treatment of various diseases.
This acid has a long history of use in medical practice. It is widely known for its analgesic, antipyretic and anti-inflammatory properties. The use of aspirin is due to its ability to inhibit the enzyme cyclooxygenase and block the synthesis of prostaglandins, mediators of inflammation.
Examples of medical uses of aspirin:

• Reduction of pain and antipyretic in fever.
• Prevention of thrombosis and heart attacks (at low doses).
• Prevention of stroke (at low doses).
• Treatment of rheumatoid arthritis and other inflammatory diseases.
• Help reduce hangover symptoms and reduce the chance of stroke and heart attack from stimulant use.
  A less common use of acetylsalicylic acid is in beauty products for skin cleansing and acne control.

Adverse Effects of Acetylsalicylic Acid

In addition to the positive effects of acetylsalicylic acid on the body is important to consider the side effects.

Gastrointestinal problems
With prolonged and excessive use of aspirin, it is possible to develop stomach and intestinal ulcers, as well as bleeding from the digestive organs.

Allergic reactions
Some people may develop an allergic reaction to acetylsalicylic acid, which can manifest as skin rashes, itching and even anaphylactic shock.

Effect on the nervous system
Large doses of acetylsalicylic acid are ototoxic and cause temporary tinnitus (ringing in the ears).

Children and pregnant women
It is not recommended to prescribe acetylsalicylic acid and preparations containing it to women in the first 3 months of pregnancy.
There is also data on possible danger of acetylsalicylic acid use in children to reduce fever in influenza, acute respiratory and other febrile diseases due to observed cases of Reye’s syndrome (hepatogenic encephalopathy).

Overdose
Aspirin overdose can be acute or chronic. Acute overdose has a mortality rate of 2%. Chronic overdose is more often fatal, with a mortality rate of 25%.

Safety Precautions

The following personal protective measures must be observed when working with acetylsalicylic acid:

• Use of safety goggles, mask and gloves to prevent contact with eyes, respiratory tract and skin.
• Clothing should cover most of the body to minimize possible contact with the substance.
• Work in a well-ventilated area or under a fume hood to avoid inhalation.

In case of an overdose of acetylsalicylic acid, the affected person is given activated charcoal, which reduces the absorption of aspirin. For moderate and severe poisoning, intravenous sodium bicarbonate solution is prescribed. In the absence of kidney damage, potassium salts are added to the solution.

Conclusion

Acetylsalicylic acid (aspirin) is a chemical compound with a rich history. In this article, we reviewed the basic properties, chemical reactions and practical applications of this substance, noting its importance in medicine and chemistry.
The use of acetylsalicylic acid in the medical field covers a wide range of possibilities, from anti-inflammatory and analgesic action to the prevention of cardiovascular diseases. The side effects of acetylsalicylic acid and precautions are also considered.

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