Organic chemistry practical course (OCP1)
WS 04/05
529-0229-00
Assistant: Fabio Di Lena
Synthesis of
4-tert-butyl-o-xylene
Presented by
Moreno Wichert
Student of Interdisciplinary Natural Sciences (Biochem.-Phys.)
D-CHAB, ETH Zurich
Nuolen SZ
December 6, 2004
1. Method
Friedel-Crafts alkylation of o-xylene with tert-butyl chloride with FeCl3 as a catalyst.
(SE-1 reaction)
2. Chemical equation
CH3
H3C
C
CH3
FeCl3
+
+
RT
HCl
Cl
C4H9Cl
C8H10
92.57 g mol-1
106.17 g mol-1
162.20 g mol-1
36.46 g mol-1
C12H18
162.27 g mol-1
3. Mechanism
CH3
H3C
C
Cl
CH3
+
+
FeCl3
Cl
Cl
Fe
Cl
+
+
H
page 2
H+
Cl
4. Experimental accomplishment
0.5 g of FeCl31 were added to a solution of 3 g of tert-butyl chloride2 and 3.8 g o-xylene3. The
solution was then stirred for an hour and then refluxed for 20 minutes. The HCl4 gas flowing
out of the Dimroth condenser was captured in a beaker with 1 M NaOH5 and neutralized.
Finally, the solution was neutralized with a saturated NaHCO36 solution, washed with a saturated NaCl solution and dried with CaCl27. The product was then purified by distillation.
Physical and safety data of the substances
1)
FeCl3 ; M = 162.20 g mol-1 ; ρ = 1.43 g cm-3 ; melting point = -9 °C ; boiling point = 110 °C ; poison
class 3 ; WGK 2 ; risk phrases: R22-34-52-53 ; safety phrases: S26-36-37-39-45-61
2)
C4H9Cl ; M = 92.57 g mol-1 ; ρ = 0.84 g cm-3 ; melting point = -28 °C ; boiling point = 51 °C ;
poison class 4 ; WGK 1 ; risk phrases: R11 ; safety phrases: S7-9-16-29
3)
C8H10 ; M = 106.17 g mol-1 ; ρ = 0.88 g cm-3 ; melting point = -25 °C ; boiling point = 144 °C ;
poison class 4 ; WGK 2 ; risk phrases: R11-20-21-38 ; safety phrases: S25
4)
HCl ; M = 36.46 g mol-1 ; ρ = 1.06 g cm-3 ; melting point = - 40 °C ; boiling point = 84 °C ;
poison class 3 ; WGK 1 ; risk phrases: R34-36-37-38 ; safety phrases: S26 ; MAK = 8 mg m-3
5)
NaOH ; M = 40.00 g mol-1 ; ρ = 2.1 g cm-3 ; melting point = 318 °C ; boiling point = 1390 °C ;
poison class 2 ; WGK 1 ; risk phrases: R35 ; safety phrases: S26-37-39-45
6)
NaHCO3 ; M = 84.01 g mol-1 ; ρ = 2.22 g cm-3 ; melting point = 270 °C ; poison class 5 ; WGK 1 ;
safety phrases: S22-24-25
7)
CaCl2 ; M = 110.99 g mol-1 ; ρ = 1.06 g cm-3 ; melting point = 772 °C ; boiling point > 1600 °C ;
poison class 5 ; WGK 1 ; risk phrases: R36 ; safety phrases: S22-23-24
Distillation apparatus (with Claisen top)
Refluxing apparatus with Dimroth condenser
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5. Analytical results and characterization
Yield after distillation:
very low - we collected all the products of all members of the lab to make an IR!
Refractive index: 1.498
IR bands [cm-1]:
2963 (C-H stretch)
1507 (aromatic system in general)
1451 - 1140 (methyl groups)
820 (2 neighbouring aromatic C-H)
6. Literature
Bülle, Jan; Hüttermann, Aloys (2000): Das Basiswissen der organischen Chemie, Stuttgart
(Georg Thieme Verlag)
Streitwieser, A.; Heathcock, C. H.; Kosower, E. M. (1994): Organische Chemie (2. Auflage),
Weinheim (VCH Verlagsgesellschaft mbH)
www.uni-saarland.de/fak8/kazmaier/ PDF_files/Praktika/Bioskript%202002.pdf (page 16)
mannose.chem.uni-potsdam.de/GPOC/721328.pdf (page 7)
http://www.spec-online.de/
http://www.chemnetbase.com/scripts/pocweb.exe
http://www.experimentalchemie.de/03-b-11.htm
http://h105.ath.cx/fwe.de/gefahrstoffdaten.de/index.html
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