In this paper is described the optimization of the esterification reaction of butyl acetate synthesis catalyzed by Candida antarctica lipase B (Novozym 435). The reaction parameters temperature, substrate molar ratio, enzyme content, and added water, and their responses measured as conversion yields, were evaluated using central composite design and response surface methodology. The best acid concentration for the reaction without enzyme inactivation was determined to be 0.3 M. The optimal conditions for butyl acetate synthesis were found to be temperature of 40 °C; substrate molar ratio of 3:1 butanol:acetic acid; enzyme content of 7.5% of substrate wt.; added water 0.25% of substrate wt. Under these conditions, over 90% of conversion was obtained in 2.5 h. Enzyme reuse was tested performing three different treatments before each batch: washing the enzyme system with either n-hexane or water, or suspending the immobilized enzyme in water for 24 h. Direct enzyme reuse or washing with water produced a rapid decrease on enzyme activity, while washing with n-hexane allowed enzyme to be reused for 6 reactions cycles keeping around 70% of its activity. This fast and high yield of conversion represents a large improvement to previously reported results.
For other uses, see Butyl acetate (disambiguation).
|Preferred IUPAC name|
|Systematic IUPAC name|
|Other names |
3D model (JSmol)
|Molar mass||116.16 g·mol−1|
|Density||0.8825 g/cm3 (20 °C)|
|Melting point||−78 °C (−108 °F; 195 K) |
|Boiling point||126.1 °C (259.0 °F; 399.2 K) at 760 mmHg|
Solubility in water
|0.68 g/100 mL (20 °C)|
|Solubility||Miscible in EtOH|
Soluble in acetone, CHCl3
Magnetic susceptibility (χ)
Refractive index (nD)
|1.3941 (20 °C)|
|1.87 D (24 °C)|
Std enthalpy of
Std enthalpy of
|GHS signal word||Warning|
GHS hazard statements
GHS precautionary statements
|Flash point||22 °C (72 °F; 295 K)|
|370 °C (698 °F; 643 K)|
Threshold limit value
|150 ppm (TWA), 200 ppm (STEL)|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|10768 mg/kg (rats, oral)|
LC50 (median concentration)
|160 ppm (rat, 4 hr)|
2000 ppm (rat, 4 hr)
391 ppm (rat, 4 hr)
1242 ppm (mouse, 2 hr)
LCLo (lowest published)
|14,079 ppm (cat, 72 min)|
13,872 ppm (guinea pig, 4 hr)
|US health exposure limits (NIOSH):|
|TWA 150 ppm (710 mg/m3)|
|TWA 150 ppm (710 mg/m3) ST 200 ppm (950 mg/m3)|
IDLH (Immediate danger)
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 ?)|
n-Butyl acetate, also known as butyl ethanoate, is an ester which is a colorless flammable liquid at room temperature. Butyl acetate is found in many types of fruit, where along with other chemicals it imparts characteristic flavors and has a sweet smell of banana or apple. It is used as a synthetic fruit flavoring in foods such as candy, ice cream, cheeses, and baked goods. Butyl acetate is often used as a high-boiling solvent of moderate polarity.
The other three isomers of butyl acetate are: isobutyl acetate, tert-butyl acetate, and sec-butyl acetate.
Butyl acetates are commonly manufactured by the Fischer esterification of butanol (or its isomer to make an isomer of butyl acetate) and acetic acid with the presence of catalytic sulfuric acid under reflux conditions with the following reaction:
Occurrence in nature
Apples, especially of the Red Delicious variety, are flavored in part by this chemical. The alarm pheromones emitted by the Koschevnikov gland of honey bees contain butyl acetate.
- ^ abcdefghijklmLide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
- ^ abcdAcetic acid, butyl ester in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD), http://webbook.nist.gov (retrieved 2014-06-28)
- ^ abcSigma-Aldrich Co., Butyl acetate. Retrieved on 2014-06-28.
- ^ abcde"MSDS of n-Butyl acetate". https://www.fishersci.ca. Fisher Scientific. Retrieved 2014-06-28.
- ^ ab"NIOSH Pocket Guide to Chemical Hazards #0072". National Institute for Occupational Safety and Health (NIOSH).
- ^ ab"n-Butyl acetate". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^Acetic acid. (2003). In Ullman's encyclopedia of industrial chemistry (6th ed., Vol. 1, pp. 170-171). Weinheim, Germany: Wiley-VCH.