Separation by Chemical Extraction

Separation by Chemical Extraction

Abstract

p-Bromoaniline, m-toluic acid and phenanthrene were extracted from a stock solution using liquid-liquid extraction. 0.315g of p-Bromoaniline, 0.030g of crude phenanthrene, and 0.730g of crude phenanthrene were extracted, with percent yields of 31.5%, 51.5%, and 36.5%, respectively. Their melting range observations, thin layer chromatography, and recrystallization were performed to test their physical properties.

Procedure Reference

Refer to the Chemistry 232 Laboratory Manual pages 17-22.

Liquid-liquid Extraction

Table 1. Reagents for Extraction

Compound

MW (g/mol)

Used

moles

Physical and Safety Data

Stock Solution A - p-bromoaniline, phenanthrene

1 g/100 mL for p-bromoaniline, 2 g/100 mL for phenanthrene

100 mL

See Products Table

See Individual Compounds

Dichloromethane

CH2Cl2

84.93

Enough to rinse

-

Bp: 39.8-40 °C(lit.)

Mp: −97 °C(lit.)

Density: 1.325 g/mL at 25 °C(lit.)

Toxic, causes skin irritation, causes serious eye irritation, may cause respiratory irritation, may cause drowsiness or dizziness, suspected of causing cancer, causes damage to organs through prolonged or repeated exposure. Avoid breathing dust/fume/gas/mist/vapours/spray.

Use personal protective equipment as required. Dispose as halogenated waste.

Hydrochloric acid

HCl

36.46

3 x 30 mL

108g

2.96

Bp: >100 °C(lit.)

Density: 1.2 g/mL at 25 °C(lit.)

37% by weight in H20, concentration is 12M. Highly toxic, corrosive. May be corrosive to metals, causes severe skin burns and eye damage; may cause respiratory irritation. This is true of the 6M and 3M solutions. Dispose as acidic aqueous waste.

Sodium hydroxide

NaOH

40.00

~ 40 mL

~ 2.13

Mp: 318 °C(lit.)

D= 2.13 g/mL. Corrosive, toxic. Dispose in “basic aqueous waste” container.

Sodium sulfate, anhydrous,

Na2SO4

142.04

4.525 g

0.03186

Mp: 884 °C(lit.)

Density: 2.68 g/mL at 25 °C(lit.)

Hygroscopic. Wrap securely (when free of solvent) and dispose in landfill waste.

p-Bromoaniline

BrC6H4NH2

172.02

1 g

0.00581

Mp: 56-62 °C(lit.)

D=1.0g/100mL at 25°C. Toxic by inhalation, contact with skin, and when swallowed. Wear protective clothing.

White powder.

Phenanthrene

C14H10

178.23

2 g

0.01122

Bp: 340 °C(lit.)

Mp: 98-100 °C(lit.)

D=2.0g/mL. Harmful if swallowed, inhaled or absorbed through skin, eye and respiratory system. Irritant. Shiny white crystals.

m-Toluic acid

CH3C6H4CO2H

136.15

1 g

0.007345

Bp: 263 °C(lit.)

Mp: 107-113 °C(lit.)

Density: 1.054 g/mL at 25 °C(lit.)

Harmful if swallowed.

Table 2. Recrystallization of Phenanthrene

Compound

MW (g/mol)

Used

moles

Physical and Safety Data

Crude Phenanthrene

C14H10

178.23

1.005 g

0.005639

Bp: 340 °C(lit.)

Mp: 98-100 °C(lit.)

D=2.0g/mL. Harmful if swallowed, inhaled or absorbed through skin, eye and respiratory system. Irritant. White and shiny solid crystals

Ethanol (Ethyl alcohol),

C2H5OH

46.07

20 mL

15.8 g

0.3430

Bp: 78 °C(lit.)

Mp: −114 °C(lit.)

Density: 0.790 g/mL at 25 °C(lit.)

Flammable liquid; irritant. Excess consumption on may lead to social consequences. Dispose as non-halogenated waste.

Water H2O

18.02

Several drops

-

Mp: