Acetophenone

Acetophenone

Names
IUPAC name 1-phenylethanone
Other names Methyl phenyl ketone; Phenylethanone; Acetophenone
Identifiers
CAS Number	98-86-2 Y
Abbreviations	ACP
ChEBI	CHEBI:27632 Y
ChEMBL	ChEMBL274467 Y
ChemSpider	7132 Y
DrugBank	DB04619 Y
Jmol 3D model	Interactive image Interactive image
KEGG	C07113 Y
PubChem	7410
UNII	RK493WHV10 Y
InChI InChI=1S/C8H8O/c1-7(9)8-5-3-2-4-6-8/h2-6H,1H3 Y Key: KWOLFJPFCHCOCG-UHFFFAOYSA-N Y InChI=1/C8H8O/c1-7(9)8-5-3-2-4-6-8/h2-6H,1H3 Key: KWOLFJPFCHCOCG-UHFFFAOYAT
SMILES O=C(c1ccccc1)C CC(=O)c1ccccc1
Properties
Chemical formula	C8H8O
Molar mass	120.15 g·mol−1
Density	1.028 g/cm3
Melting point	19–20 °C (66–68 °F; 292–293 K)
Boiling point	202 °C (396 °F; 475 K)
Solubility in water	5.5 g/L at 25 °C 12.2 g/L at 80 °C
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Acetophenone is the organic compound with the formula C₆H₅C(O)CH₃. It is the simplest aromatic ketone. This colourless, viscous liquid is a precursor to useful resins and fragrances.

Production

Acetophenone can be obtained by a variety of methods. In industry, acetophenone is recovered as a by-product of the oxidation of ethylbenzene, which mainly gives ethylbenzene hydroperoxide for use in the production of propylene oxide.

Uses

Precursor to resins

Commercially significant resins are produced from treatment of acetophenone with formaldehyde and base. The resulting polymers are conventionally described with the formula [C₆H₅C(O)CH]_x(CH₂)_x]_n, resulting from aldol condensation. These substances are components of coatings and inks. Modified acetophenone-formaldehyde resins are produced by the hydrogenation of the aforementioned ketone-containing resins. The resulting polyol can be further crosslinked with diisocyanates. These modified resins are again found in coatings, inks, as well as adhesives.

Use in pharmaceutical and related areas

Acetophenone is a raw material for the synthesis of some pharmaceuticals, examples include dextropropoxyphene and phenylpropanolamine.

Niche uses

Acetophenone is an ingredient in fragrances that resemble almond, cherry, honeysuckle, jasmine, and strawberry. It is used in chewing gum. It is also listed as an approved excipient by the U.S. FDA. In a 1994 report released by five top cigarette companies in the U.S., acetophenone was listed as one of the 599 additives to cigarettes.

Laboratory reagent

In instructional laboratories, acetophenone is converted to styrene in a two-step process that illustrates the reduction of carbonyls and the dehydration of alcohols:

4 C₆H₅C(O)CH₃ + NaBH₄ + 4 H₂O → 4 C₆H₅CH(OH)CH₃ + NaOH + B(OH)₃ → C₆H₅CH=CH₂

A similar process is used industrially but the hydrogenation step to 1-phenylethanol is done over a copper catalyst.

C₆H₅CH(OH)CH₃ → C₆H₅CH=CH₂ + H₂O

Being prochiral, acetophenone is also a popular test substrate for asymmetric hydrogenation experiments.

Natural occurrence

Acetophenone occurs naturally in many foods including apple, cheese, apricot, banana, beef, and cauliflower. It is also a component of castoreum, the exudate from the castor sacs of the mature beaver.

Pharmacology

In the late 19th and early 20th centuries, acetophenone was used in medicine. It was marketed as a hypnotic and anticonvulsant under brand name Hypnone. The typical dosage was 0.12 to 0.3 milliliters. It was considered to have superior sedative effects to both paraldehyde and chloral hydrate. In humans, acetophenone is metabolized to benzoic acid, carbonic acid, and acetone. Hippuric acid occurs as an indirect metabolite and its quantity in urine may be used to confirm acetophenone exposure.

Toxicity

The LD₅₀ is 815 mg/kg (oral, rats). Acetophenone is currently listed as a Group D carcinogen (Not Classifiable as to Human Carcinogenicity), indicating that it does not produce carcinogenic effects in humans, although no studies on humans have ever been conducted on acetophenones' carcinogenic potential. Studies have shown that acetophenone causes chromosomal damage in hamsters.