Synthesis of 4-Tert-Butyl-Ortho-Xylene by Markus Arnoldini

Synthesis of 4-tert-Butyl-ortho-Xylene by Markus Arnoldini

Laboratory Report

Synthesis of

4-tert-Butyl-ortho-Xylene

(4-tert-Butyl-1,2-dimethylbenzene)

C CH3 HC C

H C 3 C CH C C H H3C CH3

by Markus Arnoldini

1 Synthesis of 4-tert-Butyl-ortho-Xylene by Markus Arnoldini

1. Method

Friedel-Crafts-Alkylation of ortho-Xylene with tert-Butylchloride as reactant and Iron(III)chloride as catalyst.

2. Reaction Equation

FeCl3 + (CH3)3C-Cl + HCl

3. Mechanism

CH3 CH3 FeCl3 H3C C Cl C H C CH H CH3 3 3

FeCl4 + HCl

4. Physical properties of the substances

tert-Butylchloride [1] molar weight 92.57 g/mol density 0.84 g/cm3 (20 ºC) melting point ~ -28 ºC boiling point ~ 51 ºC (1013 hPa) refraction index 1.3836 CH3 WGK 1 GK (CH) 4

H3C C Cl R-phrases R 11 (highly flammable) S-phrases S 9 (keep container in a well-ventilated place) CH3 S 16 (keep away from sources of ignition – no smoking) S 29 (must not get to the canalization)

Iron(III)chloride [1] molar weight 162.21 g/mol density 2.9 g/cm3 (20 ºC) melting point - boiling point - refraction index - WGK 1 GK (CH) 3 FeCl3 R-phrases R 22 (harmful if swallowed) R 38 (irritating to skin) R 41 (risk of serious eye damage) S-phrases S 26 (in case of contact with eyes rinse with a lot of water and seek medical help) S 39 (use safety goggles)

Sodium Hydrogencarbonate [1] molar weight 84.01 g/mol density 2.22 g/ cm3 O melting point 270 °C boiling point - C refraction index - WGK 1 HO O Na GK (CH) 5 R-phrases - S-phrases - Hydrochloric Acid (conc.) [1]

molar weight 36.46 g/mol density ~ 1.19 g/cm3 (20 ºC) melting point - boiling point - refraction index - WGK 1 GK (CH) 2 HCl R-phrases R 34 (causes burns) R 36 (irritates eyes) R 37 (irritates respiratory system) R 38 (irritates skin) S-phrases S 26 (in case of contact with eyes rinse with a lot of water and seek medical help)

ortho-Xylene [1] molar weight 106.17 g/mol density 0.88 g/cm3 (20 ºC) melting point -25 ºC boiling point 144.4 ºC (1013 hPa) refraction index - WGK 2 GK (CH) 4 R-phrases R 10 (flammable) R 20/21 (harmful by inhalation and contact with skin) R 38 (irritates skin) S-phrases S 25 (avoid contact with eyes)

4-tert-Butyl-ortho-Xylene [2] molar weight 162.27 g/mol density 0.868 g/cm3 melting point - boiling point 200-209 °C refraction index 1.499-1.5 WGK - GK (CH) - R-phrases - S-phrases S 23 (do not inhale gas/fumes/vapour/spray) S 24/25 (avoid contact with skin and eyes)

5. Experimental accomplishment

To a solution of 13.3 grams (0.124 moles) ortho-Xylene and 11.6 grams (0.124 moles) tert-Butylchloride, within 30 min at room temperature 0.25 grams of water- free Iron(III)chloride were added while stirring. Heavy HCl development occured, which was neutralized by a NaOH bath (see below). When no more HCl was formed, another 2.3 grams (0.025 moles) of tert-Butylchloride were added. The solution was stirred for 1 h at room temperature, then it was boiled for 15 min under reflux. After cooking the fluid was transferred into a seperatory funnel and washed two times with a saturated solution of NaHCO3, the lower (water) phase was separated off and trashed. Then the organic phase was dried with CaCl2, and then vacuum-distilled. After the distillation an amount of 9.24 grams (0.057 moles) of 4-tert-Butyl- ortho-Xylene was received, which is a yield of 45.56 %.

6. Experimental setup

HCl gas coming out

cooling water

reflux-cooler Thermometer

Beaker with NaOH solution

100 500 o C 200 150 AUS AUS 1000 750

7. Analytical results

Refraction index: nD = 1.4996

Peaks in IR spectrum: ~3220: C-H (aromatic) 2800-3000: C-H (aliphatic) 1580-1650: C-C (aromatic ring) 1350-1400: CH3 groups 800-830: C-C (aliphatic)

8. Sources

[1] http://ch.chemdat.info/mda/ch/de/ [2] http://www.inventory-loc.ethz.ch/search?for=ccd&pri=CHF&search_type=22 &search= 12+12+C+14.13+-5.37+C+11.70+-3.97+C+8.07+-7.47+C+9.28+- 9.57+C+8.07+-8.87+C+12.92+-7.47+C+11.70+-8.17+C+10.49+- 6.07+C+12.92+-6.07+C+11.70+-5.37+C+10.49+-7.47+C+9.28+- 8.17+1+9+1+2+10+1+3+12+1+4+12+1+5+12+1+6+7+2+6+9+1+7+11+1+8+ 10+1+8+11+2+9+10+2+11+12+1&submit22.x=38&submit22.y=9&submit22 =Exact+Search [3] meanings of R and S phrases from Reinhard Keese: “Grundoperationen der präparativen Organischen Chemie – Eine Einführung”, 2003, S 193-197