acetone

Structural formula
General
Surname	acetone
other names	Propan-2-one ( IUPAC ) Propanone 2-propanone Dimethyl ketone Acetonum (pharm.) Spiritus pyroaceticus ACETONE ( INCI )
Molecular formula	C 3 H 6 O
Brief description	colorless liquid with a sweet odor
External identifiers / databases
CAS number 67-64-1 EC number 200-662-2 ECHA InfoCard 100,000,602 PubChem 180 ChemSpider 175 Wikidata Q49546
properties
Molar mass	58.08 g mol −1
Physical state	liquid
density	0.79 g cm −3 (20 ° C)
Melting point	−95 ° C
boiling point	56 ° C
Vapor pressure	246 hPa (20 ° C) 378 hPa (30 ° C) 563 hPa (40 ° C) 815 hPa (50 ° C)
solubility	miscible with water and many organic solvents
Dipole moment	2.88 (3) D (9.6 x 10 -30  C · m )
Refractive index	1.3588 (20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 225-319-336 EUH: 066 P: 210-240-305 + 351 + 338-403 + 233
MAK	DFG / Switzerland: 500 ml m −3 or 1200 mg m −3
Toxicological data	5800 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Acetone or acetone [ at͡səˈtoːn ] is the common name for the organic-chemical compound propanone or dimethyl ketone . Acetone is a colorless liquid and is used as a polar, aprotic solvent and as a starting material for many syntheses in organic chemistry. With its structural feature of the carbonyl group (> C = O), which carries two methyl groups , it is the simplest ketone .

Extraction and presentation

Acetone was first produced in 1606 by Andreas Libavius by heating lead (II) acetate . In 1661 Robert Boyle was able to win it through the dry distillation of wood. It was first described in 1610 in the Tyrocinium Chymicum by Jean Beguin . Until the middle of the 20th century, the acetone-butanol-ethanol fermentation discovered and patented by Chaim Weizmann was an important process for the production of acetone as well. The anaerobic bacterium Clostridium acetobutylicum was used for industrial production .

The most important manufacturing process of acetone today is the cumene hydroperoxide process , which is also known as the Hock phenol synthesis :

Here benzene and propene are first converted into isopropylbenzene ( cumene ) by a Friedel-Crafts alkylation in an acid . This then reacts with oxygen in a radical reaction to form the hydroperoxide , which decomposes to phenol and acetone during acidic processing .

The dehydrogenation or oxydehydrogenation of isopropanol serves as a further manufacturing process .

Another way of producing acetone is to heat calcium acetate ( 1 ), where it breaks down into acetone ( 2 ) and calcium oxide ("lime salt distillation").

This process goes back to the above-mentioned historical synthesis by Libavius ​​in 1606.

properties

Acetone is a colorless, low-viscosity liquid with a characteristic, slightly sweet odor, highly flammable and forms an explosive mixture with air. The boiling point at normal pressure is 56 ° C. It is miscible with water and most organic solvents in all proportions. The acetone molecule shows keto-enol tautomerism ; its pK _s value is 20. acetone may be due to its polar carbonyl group with cations also form complex compounds.

The compound forms azeotropically boiling mixtures with a number of other solvents . The azeotropic compositions and boiling points can be found in the following table. No azeotropes are formed with water , ethanol , 1-propanol , 2-propanol , n-butanol , benzene , toluene , ethylbenzene , diethyl ether , ethyl acetate and acetonitrile .

Azeotropes with various solvents
solvent		n -pentane	n -hexane	n -heptane	Cyclohexane	Methanol	chloroform	Carbon tetrachloride	Diisopropyl ether	Methyl acetate
Content of acetone	in%	21st	59	90	67	88	22nd	89	61	50
boiling point	in ° C	32	50	56	53	55	64	56	54	55

Thermodynamic properties

According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in bar, T in K) with A = 4.42448, B = 1312.253 and C = −32.445 in the temperature range from 259.2 to 507.6 K.

Compilation of the most important thermodynamic properties

property	Type	Value [unit]	Remarks
Standard enthalpy of formation	Δ f H 0 liquid Δ f H 0 gas	−249.4 kJ mol −1 −218.5 kJ mol −1	as a liquid as a gas
Enthalpy of combustion	Δ c H 0 gas	−1821.4 kJ mol −1
Heat capacity	c p	125.45 J mol −1 K −1 (25 ° C) 2.16 J g −1 K −1 (25 ° C) 75.02 J mol −1 K −1 (25 ° C ) 1.29 J g −1 K −1 (25 ° C)	as a liquid as a gas
Critical temperature	T c	508.15K
Critical pressure	p c	47.582 bar
Critical density	ρ c	4.63 mol·l −1
Acentric factor	ω c	0.30653
Enthalpy of fusion	Δ f H	5.72 kJ mol −1	at the melting point
Enthalpy of evaporation	Δ V H	29.1 kJ mol −1	at normal pressure boiling point

The temperature dependence of the evaporation enthalpy can be ^calculated according to the equation Δ _V H ⁰ = A e ^{(−βT _r )} (1 − T _r ) ^β (Δ _V H ⁰ in kJ / mol, T _r = (T / T _c ) reduced temperature ) with A = 46.95 kJ / mol, β = 0.2826 and T _c = 508.2 K in the temperature range between 298 K and 363 K. The specific heat capacity can be calculated in the temperature range between 5 ° C and 50 ° C via a linear function with c _p = 1.337 + 2.7752 · 10 ⁻³ · T (with c _p in kJ · kg ⁻¹ · K ⁻¹ and T in K) can be estimated.

• 

  Vapor pressure function of acetone

• 

  Temperature dependence of the heat of vaporization of acetone

• 

  Specific heat capacity of acetone

Safety-related parameters

Acetone forms highly flammable vapor-air mixtures. The compound has a flash point below −20 ° C. The explosion range is between 2.5 vol.% (60 g / m³) as the lower explosion limit (LEL) and 14.3 vol.% (345 g / m³) as the upper explosion limit (UEL). A correlation of the explosion limits with the vapor pressure function results in a lower explosion point of −23 ° C and an upper explosion point of 8 ° C. The explosion limits are pressure dependent. A reduction in pressure leads to a reduction in the explosion area. The lower explosion limit changes only slightly up to a pressure of 100 mbar and only increases at pressures below 100 mbar. The upper explosion limit decreases analogously with falling pressure.

Explosion limits under reduced pressure (measured at 100 ° C)
pressure	in mbar	1013	800	600	400	300	250	200	150	100	50	25th
Lower explosion limit (LEL)	in% by volume	2.2	2.2	2.3	2.3	2.4	2.4	2.5	2.6	2.7	3.6	5.0
	in g m −3	53	53	53	55	57	58	59	61	63	86	119
Upper explosion limit (UEL)	in% by volume	14.3	14.0	13.7	13.4	13.2	13.1	13.1	13.1	12.5	10.3	9.0
	in g m −3	345	338	331	324	319	316	316	316	302	249	217

Maximum explosion pressure under reduced pressure
pressure	in mbar	1013	800	600	400	300	200	100
Maximum explosion pressure (in bar)	at 20 ° C	9.3	7.5	5.5	3.6	2.7	1.8	0.8
	at 100 ° C	7.4		4.5

The maximum explosion pressure is 9.7 bar. As the temperature rises and the outlet pressure falls, the maximum explosion pressure falls. The limit gap width was determined to be 1.04 mm (50 ° C). This results in an assignment to explosion group IIA. With a minimum ignition energy of 1.15 mJ, vapor-air mixtures are extremely ignitable. The ignition temperature is 535 ° C. The substance therefore falls into temperature class T1. A sharp drop in the ignition temperature is observed under increased pressure. The electrical conductivity is rather low at 4.9 · 10 ⁻⁷ S · m ⁻¹ .

Ignition temperatures under increased pressure
pressure	in cash	1	2	4th	6.8	16.5
Ignition temperature	in ° C	535	345	290	265	250

Reactions (selection)

Iodination of acetone

A special reaction here is the iodination of acetone as a classic example of pseudo-zero order reaction kinetics . Since only the enol form can be iodinated, but acetone is almost 100% ketone, the 2-propenol concentration during the reaction can be regarded as constant. Its C = C double bond reacts with iodine , splitting off an iodide ion to form a mesomeric cation, which then transfers a proton to an iodide ion.

The establishment of the keto-enol equilibrium is acid (and also base) catalyzed. The iodination is therefore greatly accelerated by the resulting hydrogen iodide ( autocatalysis ).

Iodoform reaction

When adding base, however, the iodoform reaction takes place:

Formation of dibenzalacetone

Acetone reacts in the presence of benzaldehyde in an alkaline solution to form dibenzalacetone . The reaction takes place according to the general mechanism of aldol condensation .

Also benzalaniline be synthesized - it reacts aniline with the at-in alkaline solution acetone elimination of water to Schiff base ( azomethine ). Both dibenzalacetone and benzalaniline are valuable substances because they have very reactive double bonds that can be attacked by nucleophiles .

Formation of diacetone alcohol

If two acetone molecules are allowed to dimerize in an aldol-like manner under the influence of basic reagents, diacetone alcohol is formed :

Formation of acetone peroxide

Acetone reacts with hydrogen peroxide to form acetone peroxide, which tends to detonate :

Reaction with chloroform

Acetone and chloroform must not be mixed in higher concentrations because a very violent reaction occurs in the presence of traces of alkaline substances, producing 1,1,1-trichloro-2-methyl-2-propanol . For this reason, too, chlorinated and non-chlorinated solvent waste should be collected separately in the laboratory.

use

Acetone is the starting material for numerous syntheses in the chemical industry. It is mainly used to manufacture polymethyl methacrylate (PMMA), colloquially known as acrylic glass or plexiglass. To do this, the acetone is first converted into acetone cyanohydrin by adding hydrocyanic acid , which easily splits off water in an acidic environment ( mesomeric stabilization of the double bond due to conjugation to the triple bond of the nitrile group). The resulting 2-methylpropenenitrile is converted to methyl methacrylate by adding a mixture of concentrated sulfuric acid and methanol , which is polymerized to acrylic glass in a further step.

Acetone is used industrially as a precursor for the production of diacetone alcohol by aldol addition and thus indirectly as a precursor for mesityl oxide and methyl isobutyl ketone .

Styrofoam , dissolved by a drop of acetone

Acetone is also used in small quantities as a useful solvent for resins , fats and oils, rosin , cellulose acetate, as well as nail polish remover and plastic glue. It is also used to remove contamination caused by construction foam, for example when cleaning PU foam guns. It dissolves many times its volume in ethyne (acetylene).

In some countries acetone is added in small proportions (1: 2000 - 1: 5000) to gasoline or diesel in order to achieve a more complete combustion of the fuel.

In photochemical circuit board production , acetone is used for the final degreasing of the circuit board before soldering.

Acetone-containing solutions are used in dentistry to clean prepared dentin surfaces and root canals .

biochemistry

Acetone is a ketone body formed in the liver that cannot be metabolized to any significant extent. It is therefore released through the lungs or, in exceptional cases , through the urine ( acetonuria , a symptom of diabetes mellitus ). Other ketone bodies are acetoacetic acid and 3-hydroxybutanoic acid . These can be processed in the metabolism and are involved in providing energy for the muscles.

toxicology

Acetone causes dryness on the skin as it degreases the skin. Therefore, you should grease the affected areas after contact. Inhalation of larger doses causes bronchial irritation, tiredness and headache. Very high doses have a narcotic effect .

Hexadeuteroacetone

Deuterated acetone

Deuterated acetone (empirical formula: C ₃ D ₆ O), also called acetone-d ₆ , is used as a solvent in nuclear magnetic resonance spectroscopy (NMR).

The physical properties are slightly different from the non-deuterated compound:

• Melting point: -93.8 ° C
• Boiling point: 55.5 ° C
• Density: 0.872 g / ml (25 ° C)
• Refractive index: 1.355 (20 ° C)

Web links

Wiktionary: Aceton  - explanations of meanings, word origins, synonyms, translations

• Entry for Acetone in the Consumer Product Information Database

Individual evidence

1. ↑ Entry on ACETONE in the CosIng database of the EU Commission, accessed on February 16, 2020.
2. ↑ ^{a b c d e f g h i j k l m n o} Entry on acetone in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
3. ↑ Peter B. Fleming, Robert E. McCarley: Chemistry of Polynuclear Metal Halides. IV. Electronic Spectra of Some Niobium and Tantalum M ₆ X ₁₂ ^{n +} Cluster Derivatives . In: Inorganic Chemistry . tape 9 , no. 6 , June 1970, p. 1347-1354 , doi : 10.1021 / ic50088a011 .
4. ↑ Entry on acetone. In: Römpp Online . Georg Thieme Verlag, accessed on November 10, 2014.
5. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Dipole Moments, pp. 9-52.
6. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-4.
7. ↑ Entry on Acetone in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
8. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 67-64-1 or acetone ), accessed on November 2, 2015.
9. ↑ chemgapedia.de , learning unit acetone synthesis.
10. ↑ ^{a b} I. M. Smallwood: Handbook of organic solvent properties. Arnold, London 1996, ISBN 0-340-64578-4 , pp. 27-29.
11. ↑ D. Ambrose, CHS Sprake, R. Townsend: Thermodynamic Properties of Organic Oxygen Compounds. XXXIII. The Vapor Pressure of Acetone. In: J. Chem. Thermodyn. 6, 1974, pp. 693-700, doi: 10.1016 / 0021-9614 (74) 90119-0 .
12. ↑ ^{a b} K. B. Wiberg, LS Crocker, KM Morgan: Thermochemical Studies of Carbonyl Compounds. 5. Enthalpies of Reduction of Carbonyl Groups. In: J. Am. Chem. Soc. 113, 1991, pp. 3447-3450, doi: 10.1021 / ja00009a033 .
13. ^ CB Miles, H. Hunt: Heats of Combustion. I. The Heat of Combustion of Acetone. In: J. Phys. Chem. 45, 1941, pp. 1346-1359; doi: 10.1021 / j150414a002 .
14. ↑ ^{a b c} R. Malhotra, LA Woolf: Thermodynamic Properties of Propanone (Acetone) at Temperatures from 278 K to 323 K and Pressures up to 400 Mpa. In: J. Chem. Thermodyn. 23, 1991, pp. 867-876, doi: 10.1016 / S0021-9614 (05) 80282-4 .
15. ↑ ^{a b} J. Chao: Thermodynamic Properties of Key Organic Oxygen Compounds in the Carbon Range C ₁ to C ₄ . Part 2. Ideal Gas Properties. In: J. Phys. Chem. Ref. Data . 15, 1986, pp. 1369-1436, doi: 10.1063 / 1.555769 .
16. ↑ ^{a b c} A. N. Campbell, RM Chatterjee: The critical constants and orthobaric densities of acetone, chloroform benzene, and carbon tetrachloride . In: Canadian Journal of Chemistry . 47, 1969, pp. 3893-3898, doi : 10.1139 / v69-646 .
17. ↑ J. Schmidt: Design of safety valves for multi-purpose systems according to ISO 4126-10. In: Chem. Ing. Techn. 83, 2011, pp. 796-812, doi: 10.1002 / cite.201000202 .
18. ↑ KK Kelley: The heats capacities of isopropyl alcohol and acetone from 16 to 298 ° K and the corresponding entropies and free energies. In: J. Am. Chem. Soc. 51, 1929, pp. 1145-1150, doi: 10.1021 / ja01379a022 .
19. ^ ^{A b} V. Majer, V. Svoboda: Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation. Blackwell Scientific Publications, Oxford 1985, p. 300.
20. ↑ ^{a b c d e} E. Brandes, W. Möller: Safety-related parameters. Volume 1: Flammable Liquids and Gases. Wirtschaftsverlag NW - Verlag für neue Wissenschaft, Bremerhaven 2003.
21. ↑ ^{a b c d} D. Pawel, E. Brandes: Final report on the research project, the dependence of safety parameters on the pressure below atmospheric pressure. ( Memento of December 2, 2013 in the Internet Archive ), Physikalisch-Technische Bundesanstalt (PTB), Braunschweig 1998.
22. ↑ JB Fenn: Lean Flammability Limit and Minimum Spark Ignition Energy. Commercial Fluids and Pure Hydrocarbons. In: Ind. Eng. Chem. 43, 1951, pp. 2865-2869; doi: 10.1021 / ie50504a057 .
23. ↑ HF Calcote, CA Gregory, CM Barnett, RB Gilmer: Spark Ignition - Effect of Molecular Structure. In: Ind. Eng. Chem. 44, 1952, pp. 2656-2662; doi: 10.1021 / ie50515a048 .
24. ↑ Technical rule for hazardous substances TRGS 727, BG RCI leaflet T033 Avoidance of ignition hazards due to electrostatic charges , status August 2016, Jedermann-Verlag Heidelberg, ISBN 978-3-86825-103-6 .
25. ^ FA Carey, RJ Sundberg: Organic Chemistry. Wiley-VCH Verlag, 2004, ISBN 3-527-29217-9 .
26. ↑ Lutz Roth, Ursula Weller: Hazardous Chemical Reactions , ISBN 3-609-73090-0 , ecomed security; 2005.
27. ↑ External identifiers of or database links for Deuterated Acetone : CAS number: 666-52-4, EC number: 211-563-9, ECHA InfoCard: 100.010.514 , PubChem : 522220 , ChemSpider : 455535 , Wikidata : Q1032873 .
28. ↑ Acetone-d6 data sheet from Sigma-Aldrich , accessed on August 31, 2019 ( PDF ).
29. ↑ Compared to 0.791 g / ml (25 ° C) for the nondeuterated compound. Acetone data sheet from Sigma-Aldrich , accessed on August 31, 2019 ( PDF ).