Butyl Ethanoate Synthesis Essay

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).

Names
Preferred IUPAC name
Systematic IUPAC name
Other names

n-Butyl acetate
Acetic acid n-butyl ester
Butile

Identifiers

CAS Number

3D model (JSmol)

AbbreviationsBuAcO
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard100.004.236
EC Number204-658-1
KEGG

PubChemCID

RTECS numberAF7350000
UNII
UN number1123

InChI

  • InChI=1S/C6H12O2/c1-3-4-5-8-6(2)7/h3-5H2,1-2H3 Y
    Key: DKPFZGUDAPQIHT-UHFFFAOYSA-N Y
  • InChI=1/C6H12O2/c1-3-4-5-8-6(2)7/h3-5H2,1-2H3

    Key: DKPFZGUDAPQIHT-UHFFFAOYAF

Properties

Chemical formula

C6H12O2
Molar mass116.16 g·mol−1
AppearanceColorless liquid
OdorFruity
Density0.8825 g/cm3 (20 °C)[1]
Melting point−78 °C (−108 °F; 195 K) [1]
Boiling point126.1 °C (259.0 °F; 399.2 K) at 760 mmHg[1]

Solubility in water

0.68 g/100 mL (20 °C)[1]
SolubilityMiscible in EtOH
Soluble in acetone, CHCl3[1]
log P1.82[1]
Vapor pressure
  • 0.1 kPa (−19 °C)
  • 1.66 kPa (24 °C)[1]
  • 44.5 kPa (100 °C)[2]

Henry's law
constant (kH)

0.281 L·atm/mol

Magnetic susceptibility (χ)

−77.47·10−6 cm3/mol
Thermal conductivity
  • 0.143 W/m·K (0 °C)
  • 0.136 W/m·K (25 °C)
  • 0.130 W/m·K (50 °C)
  • 0.116 W/m·K (100 °C)[1]

Refractive index (nD)

1.3941 (20 °C)[1]
Viscosity
  • 1.002 cP (0 °C)
  • 0.685 cP (25 °C)
  • 0.5 cP (50 °C)
  • 0.305 cP (100 °C)[1]
Structure

Dipole moment

1.87 D (24 °C)[1]
Thermochemistry

Specific
heat capacity (C)

225.11 J/mol·K[2]

Std enthalpy of
formation (ΔfH298)

−609.6 kJ/mol[2]

Std enthalpy of
combustion (ΔcH298)

3467 kJ/mol[2]
Hazards
Main hazardsFlammable
GHS pictograms[3]
GHS signal wordWarning

GHS hazard statements

H226, H336[3]

GHS precautionary statements

P261[3]
NFPA 704
Flash point22 °C (72 °F; 295 K)[4]

Autoignition
temperature

370 °C (698 °F; 643 K)[4]

Threshold limit value

150 ppm[1] (TWA), 200 ppm[1] (STEL)
Lethal dose or concentration (LD, LC):

LD50 (median dose)

10768 mg/kg (rats, oral)[4]

LC50 (median concentration)

160 ppm (rat, 4 hr)
2000 ppm (rat, 4 hr)
391 ppm (rat, 4 hr)
1242 ppm (mouse, 2 hr)[6]

LCLo (lowest published)

14,079 ppm (cat, 72 min)
13,872 ppm (guinea pig, 4 hr)[6]
US health exposure limits (NIOSH):

PEL (Permissible)

TWA 150 ppm (710 mg/m3)[4]

REL (Recommended)

TWA 150 ppm (710 mg/m3) ST 200 ppm (950 mg/m3)[5]

IDLH (Immediate danger)

1700 ppm[5]
Related compounds

Related acetates

Ethyl acetate
Propyl acetate
Amyl acetate

Related compounds

Butanol

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

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.

Production[edit]

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:[7]

Occurrence in nature[edit]

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.

References[edit]

External links[edit]

  1. ^ abcdefghijklmLide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0. 
  2. ^ 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)
  3. ^ abcSigma-Aldrich Co., Butyl acetate. Retrieved on 2014-06-28.
  4. ^ abcde"MSDS of n-Butyl acetate". https://www.fishersci.ca. Fisher Scientific. Retrieved 2014-06-28. 
  5. ^ ab"NIOSH Pocket Guide to Chemical Hazards #0072". National Institute for Occupational Safety and Health (NIOSH). 
  6. ^ ab"n-Butyl acetate". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH). 
  7. ^Acetic acid. (2003). In Ullman's encyclopedia of industrial chemistry (6th ed., Vol. 1, pp. 170-171). Weinheim, Germany: Wiley-VCH.

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