Acetanilide
[CAS# 103-84-4]

Identification

• Classification: Organic raw materials >> Amino compound >> Cycloalkylamines, aromatic monoamines, aromatic polyamines and derivatives and salts
• Name: Acetanilide
• Synonyms: N-Phenylacetamide
• Molecular Formula: C₈H₉NO
• Molecular Weight: 135.16
• CAS Registry Number: 103-84-4
• EC Number: 203-150-7
• SMILES: CC(=O)NC1=CC=CC=C1

Properties

• Density: 1.121 g/mL (Expl.)
• Melting point: 113-115 °C (Expl.)
• Boiling point: 304 °C (Expl.)
• Flash point: 161 °C *Expl.)
• Water solubility: 5 g/L (25 °C)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302
• Safety Statements: P264-P270-P301+P317-P330-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Reproductive toxicity	Repr.	2	H361d
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H312
Specific target organ toxicity - single exposure	STOT SE	1	H370
Reproductive toxicity	Repr.	2	H361
Acute toxicity	Acute Tox.	4	H332
Specific target organ toxicity - single exposure	STOT SE	3	H336

Discovery and Applications

Acetanilide is an organic compound that belongs to the class of acylated anilines. It was first synthesized in the mid-19th century and became one of the earliest analgesic and antipyretic drugs used in medicine. Its molecular structure consists of an aniline group with an acetyl functional group, which enhances its stability and modifies its biological activity. The discovery of acetanilide marked a significant advancement in pharmaceutical chemistry and paved the way for the development of safer and more effective drugs.

Acetanilide was first introduced as a medicinal compound in the 1880s when it was found to possess fever-reducing and pain-relieving properties. Initially marketed under various trade names, it gained popularity as a treatment for fever and headaches. However, prolonged use revealed its toxic effects, including methemoglobinemia, a condition in which oxygen transport in the blood is impaired. These adverse effects led to the eventual replacement of acetanilide with its safer derivatives, such as paracetamol (acetaminophen), which remains a widely used analgesic and antipyretic today.

Despite its decline in pharmaceutical applications, acetanilide continues to be utilized in various industrial and chemical processes. It serves as a precursor in the synthesis of dyes, rubber accelerators, and stabilizers for cellulose esters. Its role in the production of azo dyes is particularly significant, as it provides the structural framework for many colorants used in textiles, plastics, and printing inks. The compound's ability to enhance the thermal stability of rubber has also made it an important additive in the manufacturing of vulcanized rubber products.

In the field of agriculture, acetanilide derivatives have been developed as herbicides, particularly in the control of weed growth in crops such as corn and soybeans. These derivatives exhibit selective action against undesirable plant species while minimizing harm to the cultivated crops. The herbicidal properties of acetanilide-based compounds have been extensively studied, leading to the development of improved formulations with enhanced efficacy and reduced environmental impact.

Acetanilide has also played a role in academic and industrial research. It is frequently used as a model compound in organic chemistry laboratories for studying amide functional groups and their reactions. Its reactivity and structural properties make it a valuable reference substance for experiments involving acetylation, hydrolysis, and reduction reactions.

Environmental and safety concerns regarding acetanilide and its derivatives have led to stringent regulations on their use. While acetanilide itself is no longer employed as a drug, its industrial applications continue under controlled conditions to ensure minimal exposure and environmental contamination. Researchers continue to explore alternative compounds that retain the beneficial properties of acetanilide while mitigating its toxic effects.

The legacy of acetanilide in pharmaceutical and industrial chemistry remains significant. Its discovery and widespread use in the late 19th and early 20th centuries contributed to the advancement of medicinal chemistry and the development of safer analgesic compounds. Although its direct medical applications have ceased, its role in chemical synthesis, materials science, and agricultural chemistry ensures its continued relevance in various scientific and industrial fields.

References

1954. ASCORBIC ACID IN AROMATIC HYDROXYLATION. III. EFFECT OF ASCORBIC ACID ON HYDROXYLATION OF ACETANILIDE, ANILINE AND ANTIPYRINE IN VIVO. The Journal of Pharmacology and Experimental Therapeutics, 111(2).
DOI: 10.1016/s0022-3565(25)11199-3

1964. Role of Some Hormones and Acetanilid on the Production of Lumbosacral Neuronal Inclusions in the Pigeon. Gerontologia, 9(2-3).
DOI: 10.1159/000211251

2024. Sequential two photon nonlinear absorption and optical limiting action of 3-nitroacetanilide (3NAA) embedded in polymeric nanofibers. Journal of Materials Science: Materials in Electronics, 35(22).
DOI: 10.1007/s10854-024-13423-5