ACETOPHENONE

Acetophenone is an aromatic ketone with the formula C₆H₅COCH₃, appearing as a colorless, oily liquid with a sweet, floral odor reminiscent of orange blossom or almond.
From an industrial perspective, acetophenone is widely used as a precursor and intermediate in the manufacture of resins, plastics, pharmaceuticals, and fine chemicals, while also serving as a fragrance and flavor ingredient in perfumes, soaps, cosmetics, and detergents.
Overall, acetophenone is a multifunctional chemical bridging natural occurrence, fragrance and flavor design, pharmaceutical synthesis, and industrial chemistry, highlighting its versatility and importance across multiple scientific and commercial fields.

CAS Number: 98-86-2
EC Number: 202-708-7
Molecular Formula: C6H8O
Molecular Weight: 120.15 g/mol

Synonyms: Acetophenone, 1-Phenylethanone, Phenylethanone, Methyl phenyl ketone, Acetylbenzene, Hypnone, API (Acetophenone), Ethyl phenyl ketone (archaic), Benzoylmethane, 1-Phenyl-1-oxopropane (rare), Acetylbenzol, Phenyl methyl ketone, α-Oxoethylbenzene, α-Ketoethylbenzene, Phenylacetyl, Acetophenon (German spelling), Acétophénone (French spelling), Acetofenona (Spanish/Italian spelling), Phényléthanone, 1-Oxo-1-phenylethane, Acetylbenzolum, 1-Phenylacetone (often confused, used historically), NSC 8819 (registry), FEMA No. 2009 (flavor code), EINECS 202-708-7 (registry synonym), BRN 636113 (Beilstein registry), UNII: CHH8B74VVN (FDA code), PubChem Substance ID 24893836, ChemIDplus entry: 98-86-2, Aceto-phenone (variant spelling), Acétophénon (rare French variant), Benzoyl methane, Benzenecarbonylmethane, Ethylidene phenyl ketone, Acetylphenyl, PhCOCH₃ (formula shorthand), CH₃COPh (formula shorthand), 2-Oxo-2-phenylethane, Ethyl phenone (archaic), Phenacyl methyl, A.Phenone (abbreviation in some catalogues), 1-Phenylacetyl group (fragment synonym), FEMA Flavor Ingredient 2009, Acetophenonas (Latinized), HSDB 1391 (Hazardous Substances Data Bank ID), Acetylbenzenum (old pharma Latin), Phenyl-CO-CH₃ (descriptive shorthand), Acetyl-benzenone (variant name), Benzenemethylketone (variant registry), Acetylbenzyl ketone (rare synonym)

Acetophenone is an aromatic ketone with the formula C₆H₅COCH₃, appearing as a colorless, oily liquid with a sweet, floral odor reminiscent of orange blossom or almond.
Acetophenone is the simplest aromatic ketone, consisting of a phenyl group attached to a carbonyl group with a methyl substituent.

Acetophenone occurs naturally in some fruits and is widely used in the fragrance and flavor industry as a component of perfumes, soaps, and cosmetics due to its pleasant scent.
Industrially, Acetophenone serves as an important intermediate in the synthesis of pharmaceuticals, resins, and fine chemicals, and it has historically been employed as a hypnotic and sedative agent under the name Hypnone.
Although less common in modern therapeutics, acetophenone remains valuable as both a versatile chemical building block and a functional additive in consumer products.

Acetophenone is an aromatic ketone and the simplest representative of the acetylbenzenes, consisting of a phenyl ring attached to a carbonyl group with a methyl substituent.
Acetophenone appears as a colorless to slightly yellow, oily liquid with a characteristic sweet, floral, and almond-like odor that makes it a valuable compound in perfumery and flavoring applications.
Naturally, acetophenone is found in small amounts in fruits such as apple, apricot, banana, and also in certain essential oils including cherry and castoreum, contributing to their distinctive aromas.

From an industrial perspective, acetophenone is widely used as a precursor and intermediate in the manufacture of resins, plastics, and specialty chemicals.
Acetophenone is an important building block for the synthesis of pharmaceuticals, including certain hypnotics, anti-inflammatory agents, and other fine chemicals. 

Acetophenone's fragrance properties have made it a common additive in perfumes, soaps, cosmetics, and detergents, where it enhances floral and sweet notes.
In the flavor industry, Acetophenone is employed at low concentrations to impart a pleasant taste reminiscent of orange blossom, vanilla, or almond.

Medically, acetophenone was historically used as one of the earliest synthetic hypnotics and sedatives under the name Hypnone.
Although Acetophenone has largely been replaced by safer and more effective modern drugs, this application underscores its pharmacological importance in the early development of therapeutic agents.
Today, acetophenone’s relevance in medicine is more as a synthetic intermediate rather than as a direct active drug.

Chemically, acetophenone is moderately volatile and combustible, with good solubility in organic solvents but limited solubility in water.
Acetophenone is generally stable under normal conditions, though it can undergo oxidation and photodegradation upon prolonged exposure to air and light, leading to the formation of benzoic acid and related compounds.
Because of its reactivity, acetophenone is an essential raw material in organic synthesis, particularly in Friedel–Crafts acylation reactions, and serves as a starting material for the production of heterocyclic compounds and substituted derivatives with diverse industrial applications.

In terms of safety and environmental aspects, acetophenone is considered to have relatively low acute toxicity, but it can cause skin, eye, and respiratory irritation upon contact or inhalation.
Prolonged exposure at high concentrations may have central nervous system effects such as drowsiness, headache, or nausea.
Environmentally, acetophenone is biodegradable to some extent, but care must still be taken in industrial use and disposal to prevent accumulation and contamination.

Overall, acetophenone is a multifunctional chemical bridging natural occurrence, fragrance and flavor design, pharmaceutical synthesis, and industrial chemistry.
Acetophenone's dual role as both a naturally occurring aromatic component and a synthetic intermediate highlights its versatility and importance across multiple scientific and commercial fields.

Market Overview of Acetophenone:
Acetophenone holds a significant place in both the chemical and consumer goods industries, serving as a versatile compound with applications across perfumery, flavors, pharmaceuticals, and polymer production.
Globally, the acetophenone market is driven primarily by demand in the fragrance and flavor sector, where its sweet, floral, and almond-like scent makes it valuable for perfumes, soaps, detergents, and cosmetics.

In addition to consumer goods, acetophenone is an essential intermediate in industrial chemistry, particularly in the synthesis of resins, plastics, and fine chemicals.
Acetophenone serves as a raw material for pharmaceutical agents, historically used as a sedative (Hypnone) and currently as a building block for modern drug molecules.

The market demand is further supported by Acetophenone's role in organic synthesis and specialty chemical manufacturing, including applications in coatings, inks, and agrochemicals.
Rapid industrial growth in Asia-Pacific (China, India) has made the region a key hub for acetophenone production, while Europe and North America continue to be strong markets for its use in perfumery, pharmaceuticals, and polymer industries.

The global acetophenone market is expected to grow steadily due to:
Rising demand in the personal care and cosmetics sector
Expanding pharmaceutical applications as an intermediate
Growing chemical and polymer industry requirements

However, the market faces restraints from regulatory pressures related to chemical safety, environmental persistence, and occupational exposure limits.
Despite this, acetophenone remains a strategic specialty chemical due to its unique dual role in consumer-oriented and industrial applications.

Uses of Acetophenone:
The fragrance industry widely uses acetophenone as a fragrance ingredient in perfumes, colognes, soaps, detergents, and cosmetics.
Acetophenone provides a sweet, floral, almond- or orange-blossom-like note, enhancing aromatic blends.

The food and beverage industry uses acetophenone as a flavoring agent at very low concentrations, contributing vanilla- or cherry-like undertones.
Pharmaceutical manufacturers historically used acetophenone as a sedative and hypnotic drug under the trade name Hypnone.

Modern pharmaceutical industries now primarily use acetophenone as an intermediate in drug synthesis, serving as a precursor to various active pharmaceutical ingredients (APIs).
Researchers recognize that acetophenone plays a role in the development of anti-inflammatory agents, anesthetics, and other therapeutic compounds.

The chemical industry uses acetophenone as a chemical intermediate in the manufacture of resins, plastics, and fine chemicals.
Industrial manufacturers use acetophenone in the production of styrene-based resins and polyester resins.

Organic chemists employ acetophenone as a starting material in organic synthesis, for example in the preparation of heterocycles, substituted ketones, and specialty chemicals.
The coating and agrochemical sectors apply acetophenone in coatings, inks, and agrochemicals as a building block.

Synthetic chemists utilize acetophenone in Friedel–Crafts acylation reactions as a standard substrate, while analytical chemists employ acetophenone as a reference compound in analytical chemistry due to its simple aromatic ketone structure.
Personal care product formulators include acetophenone in lotions, creams, and hair products for fragrance stabilization, and household product manufacturers sometimes incorporate acetophenone in household cleaning products to mask unpleasant chemical odors.

Fragrance & Flavor Industry:
The fragrance industry widely uses acetophenone as a fragrance ingredient in perfumes, colognes, soaps, detergents, and cosmetics.
Acetophenone provides a sweet, floral, almond- or orange-blossom-like note, enhancing aromatic blends.
The food and beverage industry uses acetophenone as a flavoring agent (at very low concentrations), contributing vanilla- or cherry-like undertones.

Pharmaceutical Applications:
Pharmaceutical manufacturers historically used acetophenone as a sedative and hypnotic drug under the trade name Hypnone.
Modern pharmaceutical industries now primarily use acetophenone as an intermediate in drug synthesis, serving as a precursor to various active pharmaceutical ingredients (APIs).
Researchers recognize that acetophenone plays a role in the development of anti-inflammatory agents, anesthetics, and other therapeutic compounds.

Industrial & Chemical Uses:
The chemical industry serves acetophenone as a chemical intermediate in the manufacture of resins, plastics, and fine chemicals.
Industrial manufacturers use acetophenone in the production of styrene-based resins and polyester resins.

Organic chemists employ acetophenone as a starting material in organic synthesis (e.g., heterocycles, substituted ketones, and specialty chemicals).
The coating and agrochemical sectors apply acetophenone in coatings, inks, and agrochemicals as a building block.

Research & Laboratory Uses:
Synthetic chemists utilize acetophenone in Friedel–Crafts acylation reactions as a standard substrate.
Analytical chemists employ acetophenone as a reference compound in analytical chemistry due to its simple aromatic ketone structure.

Consumer-Oriented Products:
Personal care product formulators include acetophenone in lotions, creams, and hair products for fragrance stabilization.
Household product manufacturers sometimes incorporate acetophenone in household cleaning products to mask unpleasant chemical odors.

Benefits of Acetophenone:
The fragrance industry benefits from acetophenone because it provides a stable, pleasant, and long-lasting sweet floral aroma that blends well with other fragrance ingredients.
The flavor industry benefits from acetophenone since it contributes delicate vanilla-, almond-, or cherry-like undertones at very low concentrations without overpowering the main flavor profile.

Pharmaceutical manufacturers value acetophenone because it acts as a versatile intermediate in drug synthesis, enabling the development of anti-inflammatory agents, anesthetics, and other therapeutic compounds.
Researchers benefit from acetophenone as it serves as a useful substrate in organic reactions and as a standard compound in analytical chemistry, supporting laboratory studies and reference analyses.

The chemical industry favors acetophenone because Acetophenone functions as a reliable building block in the production of resins, plastics, and specialty chemicals.
Industrial manufacturers benefit from acetophenone as it enhances the efficiency of polymer production, particularly for styrene-based and polyester resins.

Personal care product formulators appreciate acetophenone because it stabilizes fragrance systems and improves product consistency in lotions, creams, and cosmetics.
Household product manufacturers also benefit from acetophenone since it masks unpleasant chemical odors in cleaning products, thereby improving consumer acceptance.
Overall, industries across pharmaceuticals, fragrances, flavors, and chemicals benefit from acetophenone due to its versatility, stability, and ability to improve both product quality and industrial efficiency.

Production of Acetophenone:
The chemical industry produces acetophenone primarily through the Friedel–Crafts acylation reaction, in which benzene reacts with acetyl chloride or acetic anhydride in the presence of a Lewis acid catalyst such as aluminum chloride.
Industrial manufacturers also produce acetophenone as a by-product during the oxidation of ethylbenzene, a large-scale process used in the production of styrene.

Synthetic chemists can prepare acetophenone through the partial oxidation of cumene or through the hydrolysis of α-chloroacetophenone, although these methods are less common on an industrial scale.
Laboratories sometimes produce acetophenone via catalytic dehydrogenation of 1-phenylethanol, demonstrating its versatility in synthesis routes.

Large-scale producers favor the Friedel–Crafts pathway because Acetophenone provides high yield and economic efficiency, while the ethylbenzene oxidation route remains significant due to its integration with the styrene industry.
Researchers continually explore improved catalysts and greener methods to produce acetophenone in order to reduce environmental impact and improve selectivity.
Overall, the production of acetophenone reflects a balance between classical organic synthesis and modern industrial by-product utilization, ensuring both economic and practical availability of this valuable aromatic ketone.

Synthesis of Acetophenone:
Organic chemists synthesize acetophenone mainly by performing the Friedel–Crafts acylation reaction, where benzene reacts with acetyl chloride or acetic anhydride in the presence of a Lewis acid catalyst such as aluminum chloride.
Industrial manufacturers also synthesize acetophenone as a secondary product in the oxidation of ethylbenzene, which is a large-scale reaction used in the styrene industry.

Researchers demonstrate that acetophenone can be synthesized by the oxidation of ethylbenzene with oxygen over metal catalysts, producing acetophenone together with acetaldehyde.
Laboratory chemists synthesize acetophenone through alternative routes such as catalytic dehydrogenation of 1-phenylethanol or hydrolysis of α-chloroacetophenone, although these methods are less favorable for mass production.

The chemical industry synthesizes acetophenone using the Friedel–Crafts pathway because it provides high yields and straightforward processing. 
Synthetic chemists continue to explore greener methods for acetophenone synthesis by developing recyclable catalysts and solvent-free reactions, aiming to improve sustainability and reduce hazardous waste.
Overall, the synthesis of acetophenone combines classical organic reaction strategies with modern industrial approaches, highlighting its importance as both a laboratory compound and a large-scale industrial intermediate.

History of Acetophenone:
Chemists first identified acetophenone in the mid-19th century during the development of aromatic ketone chemistry.
Early researchers studied acetophenone as one of the simplest acetyl-substituted benzenes and recognized its unique sweet and floral odor, which led perfumers to adopt it quickly in fragrance formulations.

Pharmaceutical manufacturers began using acetophenone in the late 1800s as one of the earliest synthetic hypnotic and sedative agents under the name Hypnone.
Physicians prescribed Hypnone widely in the early 20th century, but later developments in pharmacology gradually replaced it with safer and more effective drugs.

The chemical industry incorporated acetophenone as an intermediate in resin and polymer synthesis during the early expansion of the plastics sector in the mid-20th century.
Researchers later confirmed Acetophenone's natural occurrence in certain fruits and essential oils, further supporting its use in flavor and fragrance applications.

Industrial producers expanded acetophenone production significantly in the second half of the 20th century, linking it to styrene manufacturing through the oxidation of ethylbenzene.
Modern chemists continue to study acetophenone both for its historical importance as a sedative and for its ongoing role as a versatile intermediate in pharmaceuticals, fragrances, and specialty chemicals.
Overall, the history of acetophenone reflects a transition from early medicinal use to broad industrial and consumer applications, illustrating its enduring significance in science and industry.

Handling and Storage of Acetophenone:
Handle acetophenone in well-ventilated areas, avoiding inhalation of vapors and direct contact with skin or eyes.
Use appropriate personal protective equipment (PPE), including gloves, goggles, and protective clothing.

Do not eat, drink, or smoke when handling the substance.
Store acetophenone in tightly closed containers made of compatible materials (glass, stainless steel, or lined steel).

Keep storage areas cool, dry, and well-ventilated.
Protect acetophenone from direct sunlight, heat sources, and open flames.
Keep away from incompatible substances such as strong oxidizing agents, acids, and alkali metals.

Stability and Reactivity of Acetophenone:

Chemical stability:
Stable under recommended storage and handling conditions.

Reactivity:
Acetophenone may undergo slow oxidation when exposed to air and light, producing benzoic acid and related compounds.

Conditions to avoid:
Excessive heat, open flames, prolonged light exposure, and contact with strong oxidizers.

Hazardous decomposition products:
Carbon oxides (CO, CO₂) may be released during thermal decomposition.

Incompatibility:
Avoid strong oxidizing agents, strong acids, and alkali metals.

First Aid Measures of Acetophenone:

Inhalation:
Move the exposed person to fresh air.
If breathing is difficult, administer oxygen and seek medical attention.

Skin contact:
Wash affected area thoroughly with soap and water. 
Remove contaminated clothing.
Seek medical advice if irritation develops.

Eye contact:
Flush immediately with plenty of water for at least 15 minutes while holding eyelids apart.
Seek medical attention.

Ingestion:
Rinse mouth with water.
Do not induce vomiting.

If conscious, give water to drink.
Seek immediate medical attention.

Firefighting Measures of Acetophenone:

Suitable extinguishing media:
Use dry chemical, foam, carbon dioxide (CO₂), or water spray.

Unsuitable media:
Do not use high-pressure water jets, as they may spread the liquid.

Hazards from combustion:
Fire or thermal decomposition may release irritating fumes and toxic gases such as carbon monoxide and carbon dioxide.

Protective equipment for firefighters:
Firefighters should wear self-contained breathing apparatus (SCBA) and full protective gear.

Accidental Release Measures of Acetophenone:

Personal precautions:
Wear PPE (gloves, goggles, protective clothing).
Avoid breathing vapors and prevent skin and eye contact.

Environmental precautions:
Prevent release into drains, surface water, or soil.
Acetophenone may be harmful to aquatic life.

Methods for cleaning up:
Contain the spill with inert absorbent materials (sand, vermiculite, or earth).
Transfer collected material to suitable labeled containers for disposal.

Ventilate the area and eliminate all ignition sources.
Dispose of waste according to local environmental regulations.

Exposure Controls / Personal Protection of Acetophenone:

Engineering controls:
Provide adequate general and local exhaust ventilation, especially in confined spaces.

Respiratory protection:
Use approved respirators if airborne concentrations exceed occupational exposure limits.

Hand protection:
Wear chemical-resistant gloves (nitrile, neoprene, or equivalent).

Eye protection:
Use safety goggles or a face shield to prevent splashes.

Skin/body protection:
Wear protective clothing such as a lab coat, apron, long sleeves, and closed footwear.

Hygiene measures:
Wash hands and exposed skin thoroughly after handling.
Do not eat, drink, or smoke when using acetophenone.

Identifiers of Acetophenone:
CAS Number: 98-86-2
EC Number (EINECS): 202-708-7
RTECS Number: AL4550000
UN Number (Transport): UN 1993 (classified as Flammable Liquid, N.O.S.)
IUPAC Name: 1-Phenylethanone
Molecular Formula: C₈H₈O
Molecular Weight: 120.15 g/mol
InChI Key: RWVYZUUZPJGHJG-UHFFFAOYSA-N
SMILES Notation: CC(=O)C1=CC=CC=C1

CAS Number: 98-86-2
EC Number (EINECS): 202-708-7
RTECS Number: AL4550000
UN Number (Transport): UN 1993 (classified as Flammable Liquid, N.O.S.)
IUPAC Name: 1-Phenylethanone
Molecular Formula: C₈H₈O
Molecular Weight: 120.15 g/mol
InChI (IUPAC): InChI=1S/C8H8O/c1-7(9)8-5-3-2-4-6-8/h2-6H,1H3
InChI Key: RWVYZUUZPJGHJG-UHFFFAOYSA-N
SMILES Notation: CC(=O)C1=CC=CC=C1
PubChem CID: 7410
ChemSpider ID: 7131
KEGG ID: C19134
Beilstein Registry Number: 636113
Merck Index: 14, 69

Properties of Acetophenone:
Appearance: Colorless to pale yellow oily liquid
Odor: Sweet, floral, almond- or orange-blossom-like odor
Molecular Formula: C₈H₈O
Molecular Weight: 120.15 g/mol
Density: ~1.028 g/cm³ at 20 °C
Melting Point: 19–20 °C
Boiling Point: 202 °C at 1 atm
Flash Point: 77 °C (closed cup)
Autoignition Temperature: ~615 °C
Vapor Pressure: ~0.4 mmHg at 25 °C
Vapor Density (Air = 1): ~4.1
Refractive Index: n²⁰ᴰ = 1.532–1.535
Viscosity: ~1.2 mPa·s at 25 °C
Solubility in Water: Slightly soluble (~6 g/L at 25 °C)
Solubility in Organic Solvents: Miscible with ethanol, ether, chloroform, acetone, and most organic solvents
Partition Coefficient (log P, octanol/water): 1.58
pKa (of conjugate acid): ~-5 (very weakly basic ketone carbonyl oxygen)
Stability: Stable under normal temperature and pressure, sensitive to light and air (may slowly oxidize).

State: Liquid at room temperature
Color: Colorless to pale yellow
Taste: Sweet, slightly floral (in trace concentrations)
Molar Volume: ~117.0 cm³/mol
Surface Tension: ~36 mN/m at 25 °C
Thermal Conductivity: ~0.147 W/m·K at 25 °C
Heat Capacity (Cp): ~1.72 J/g·K at 25 °C
Enthalpy of Vaporization: ~49 kJ/mol at boiling point
Dielectric Constant: ~17.4 at 20 °C
Index of Refraction (n²⁰ᴰ): 1.532–1.535
Henry’s Law Constant: ~4.7 × 10⁻⁶ atm·m³/mol (25 °C)
Critical Temperature (Tc): ~657 K (384 °C)
Critical Pressure (Pc): ~3.5 MPa
Odor Threshold: ~0.32 ppm (air)
Stability: Stable under normal storage conditions; slowly oxidizes on prolonged exposure to air and light.