Zurich, 17.11.2007
Synthesis of
Isopentyl Acetate
O
O
Tobias Langenegger
tobiasla@student.ethz.ch
05-918-362
D-Biol (chem.)
assisted by
Guo Xiaoqiang
Method
Esterification of isopentyl alcohol and glacial acetic acid catalysed by sulfuric acid.
Chemical equation
O
O
H2SO4
- H2O
+
OH
HO
O
Mechanism
O
OH
OH
H
OH
OH
OH
OH
HO
OH
+
O
HO
OH
H
HO
HO
OH
OH2
O
O
H
H
- H2O
O
O
+ H
O
O
Physical and safety data
substance
Mw
(g/mol)
density
(g/cm3)
mp
(°C)
bp
(°C)
nD20
Poison
CH
R-phrases
S-phrases
isopentyl
alcohol
88.15
0.81
-117
131
1.406
-
10, 20, 37,
66
46
glacied
acetic acid
60.05
1.151
17
117
1.371
3
10, 35
23, 26, 45
isopentyl
acetate
98.08
0.876
-78
142
1.400
5
10, 66
23, 25
H2SO4
98.08
1.836
10.4
279.6
-
2
35
26, 30, 45
NaHCO3
84.01
2.22
270
-
-
-
-
-
NaCl
58.44
2.17
801
-
-
-
-
-
MgSO4
120.37
2.66
-
-
-
-
-
-
Equipment
reflux:
distillation:
Preparation
Substance
isopentyl alcohol
glacied acetic acid
sulfuric acid
eq
1
2.537
cat.
n (mmol)
68.92
174.85
37.44
V (mL)
7.5
10
2
m (mg)
-
Experimental section
To a solution of 7.5 mL isopentyl alcohol and 10 mL glacial acetic acid, 2 mL
concentrated sulfuric acid was added drop by drop, while stirring. This solution then
was refluxed for an hour at 140 - 160 °C and after that cooled down to RT. It was
washed with water (20 mL), saturated NaHCO3 (3 x 20 mL) and saturated NaCl (20
mL) and dried over MgSO4 over night. The product was purified by distillation (110 –
130 °C) and characterized.
Yield
V
5.9 mL
m
5.1 g
n
39.7 mmol
Yield
57.6%
Characterisation
Peaks in IR spectrum
nD23.0 = 1.3989
(lit. 1.400)
~2950 cm-1
~1740 cm-1
~1230 cm-1
sat. C-H
C=O
C-O-C
Discussion
During my distillation, the process stopped and the vapour temperature decreased
(while the oil temperature was constant). After a while the temperature increased
again and more of the product could be collected. When this happened a second
time I stopped the distillation, although there was still some substance. Because this
reaction is reversible, we cannot get very high yield. It would be improved, if we
added water or alcohol as solvent (big excess).
Literature
https://www.discoverygate.com/
http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi
http://www.chemexper.com/
http://www.wikipedia.org
Attachment
-
Reference IR spectrum
Copy of the lab notebook
IR spectrum
Reference IR spectrum from
http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi