Isobutyl acetate
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| General | |||||||||||||||||||
| Surname | Isobutyl acetate | ||||||||||||||||||
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| Molecular formula | C 6 H 12 O 2 | ||||||||||||||||||
| Brief description |
colorless liquid with a fruity odor |
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| properties | |||||||||||||||||||
| Molar mass | 116.16 g mol −1 | ||||||||||||||||||
| Physical state |
liquid |
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| density |
0.87 g cm −3 (20 ° C) |
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| Melting point |
−99 ° C |
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| boiling point |
118 ° C |
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| Vapor pressure |
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| solubility |
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| Refractive index |
1.3902 (20 ° C) |
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| MAK |
DFG : 100 ml m −3 or 480 mg m −3 |
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| 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 | |||||||||||||||||||
Isobutyl acetate (according to IUPAC nomenclature : 2-methylpropyl acetate , often also referred to as isobutyl acetate ) is an organic-chemical compound from the group of carboxylic acid esters . In addition to the isomeric acetic acid n -butyl ester, it is an excellent solvent for coating materials, printing inks , lacquers as well as numerous plastics and resins .
Occurrence
Isobutyl acetate is a fruit ester that is also found in bananas . However, it is only one of many nuances that make up the typical banana taste.
Bananas
Extraction and presentation
Isobutyl acetate is produced on an industrial scale by the acid-catalyzed esterification of acetic acid with isobutanol at temperatures of 110-120 ° C. in reaction columns.
In addition to mineral acids such as sulfuric acid , acidic ion exchange resins or zeolites are also suitable as catalysts . On a laboratory scale, p-toluenesulfonic acid is usually used as the catalyst .
properties
Physical Properties
Isobutyl acetate has a relative gas density of 4.01 (density ratio to dry air at the same temperature and pressure) and a relative density of the vapor-air mixture of 1.06 (density ratio to dry air at 20 ° C. and normal pressure). In addition, isobutyl acetate has a vapor pressure of 19.9 hPa at 20 ° C, 33.9 hPa at 30 ° C, 55.4 hPa at 40 ° C and 87.7 hPa at 50 ° C. The evaporation rate is 7.2. The compound forms an azeotropic mixture with water at 87.4 ° C. The miscibility with water is only slight. Only 0.67% by mass of ester dissolves in water at 20 ° C and only 1.65% by mass of water in the ester dissolves at 20 ° C.
Thermodynamic properties
The vapor pressure function results according to Antoine according to log 10 (P) = A− (B / (T + C)) (P in bar, T in K) with A = 4.53676, B = 1625.875 and C = −32.494 in the temperature range from 2529 to 391 K.
Compilation of the most important thermodynamic properties property Type Value [unit] Remarks Enthalpy of combustion Δ c H 0 liquid −3534 kJ mol −1 Heat capacity c p 240.2 J mol −1 K −1 (17 ° C) as a liquid Critical temperature T c 561.5 K Critical pressure p c 31.8 bar Enthalpy of evaporation Δ V H 0 35.9 kJ mol −1 at normal pressure boiling point
Chemical properties
Isobutyl acetate is a highly flammable liquid from the group of carboxylic acid esters . The ester is sparingly soluble in water, but it is readily soluble in common organic solvents. In addition, the liquid is highly volatile. Explosive reactions can occur with strong oxidizing agents . Isobutyl acetate also reacts violently with alkali hydroxides or potassium tert-butoxide .
use
Isobutyl acetate is used as an excellent solvent for coating materials, printing inks and paints . Furthermore, isobutyl acetate is a very good solvent for cellulose nitrate , rosin and some other natural resins , polystyrene , polyvinyl acetate , polyvinyl , polyacrylic acid and some copolymers of vinyl chloride . It also dissolves modified phenolic resins , urea and melamine resins , ketone and epoxy resins , as well as fats and oils . Post-chlorinated polyvinyl chloride and vinyl acetate , vinyl chloride, dicarboxylic acid copolymers are somewhat less soluble, as is chlorinated rubber . Natural rubber , cellulose ethers and polyvinyl butyrals only swell. Practically insoluble are u. a. Shellac , cellulose acetate , cellulose acetobutyrate , polyvinyl formal , polyvinyl carbazole and waxes . Isobutyl acetate can be used particularly well as a solvent for nitro lacquers in order to reduce the viscosity and increase the blending ability. Isobutyl acetate is usually sold commercially as a solvent mixture with 85% isobutyl acetate and 15% isobutanol. Isobutyl acetate is also used as a fragrance and has a penetrating smell of pineapple and banana.
safety instructions
The vapors of isobutyl acetate may form explosive mixtures with air. The substance is mainly absorbed through the respiratory tract and the skin . Ingestion or exposure leads to acute irritation of the eyes and respiratory tract. At higher concentrations, a disturbance of the central nervous system can occur. Chronic consequences can be irritating effects on mucous membranes and skin changes . However, reproductive toxicity and mutagenicity could be excluded. Insufficient information is available on carcinogenicity . Isobutyl acetate has a lower explosion limit (LEL) of approx. 1.25% by volume (60 g / cm 3 ) and an upper explosion limit (UEL) of approx. 10.5% by volume (510 g / cm 3 ) . The lower explosion point is 15 ° C. The ignition temperature is 420 ° C. The substance therefore falls into temperature class T2 and explosion group IIA. With a flash point of 18 ° C, isobutyl acetate is considered highly flammable.
See also
Web links
Individual evidence
- ↑ a b c d e f g h i j k l m n o p q Entry on isobutyl acetate in the GESTIS substance database of the IFA , accessed on July 11, 2019(JavaScript required) .
- ↑ a b Entry on butyl acetate. In: Römpp Online . Georg Thieme Verlag, accessed on July 11, 2019.
- ↑ 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. 3-308.
- ↑ Entry on Isobutyl acetate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on July 11, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .
- ^ A b Jaromir Lederer, Jiri Kolena, Jiri Hanika, Pavel Moravek, Quido Smejkal, Vladimir Macek, Wiekert Willem Levering, Oliver Bailer: Process and device for the production of butyl acetate and isobutyl acetate. In: www.patent-de.com. Sulzer Chemtech AG, Winterthur, CH, November 27, 2003, accessed on July 11, 2019 .
- ^ Klaus Schwetlick et al: Organikum . 24th edition. Wiley-VCH, Weinheim 2015, ISBN 978-3-527-33968-6 .
- ^ H. Cheung, RS Tanke, GP Torrence: Acetic Acid. In: Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag, Weinheim 2005, doi : 10.1002 / 14356007.a01_045 .
- ↑ a b D. Stoye: Solvents. In: Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag, Weinheim 2005, doi : 10.1002 / 14356007.a24_437
- ^ DR Stull: Vapor Pressure of Pure Substances Organic Compounds. In: Ind. Eng. Chem. 39, 1947, pp. 517-540.
- ↑ E. Schjanberg: The heats of combustion and the refraction data of some chlorine-substituted fatty acids and esters. In: Z. Phys. Chem. Abt. A. 172, 1935, pp. 197-233.
- ^ NS Kurnakov, NK Voskresenskaya: Calorimetry of liquid binary systems. In: Izv. Akad. Nauk SSSR, Otdel. Mat. I Estestv. Nauk. Ser. Khim. 1936, pp. 439-461.
- ↑ a b A. Nadezhdin In: Rep. Phys. 23, 1887, p. 708.
- ^ JH Mathews: The accurate measurement of heats of vaporization of liquids. In: J. Am. Chem. Soc. 48, 1926, pp. 562-576, doi: 10.1021 / ja01414a002 .