Chromatography and Separation Techniques- Separating Liquids: Fractional Distillation

Separating Liquids: Fractional Distillation

Description: A liquid consisting of a 33 % v/V methanol/water is distilled. The distillate is tested for flammability, and it ignites. When the mixture is tested, no ignition occurs.

H₂O(CH₃OH) + Δ → H₂O(CH₃OH) + CH₃OH(g)

CH₃OH(g) → CH₃OH(l)

2CH₃OH(l) + 3O₂(g) → 2CO₂(g) +4H₂O(g)

Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry

Year: 1989 Vol: 3 Pages: pp 258 – 262

Keywords: Distillation, Methanol, Water, Boiling Point, Fractional Distillation

Rating:

Hazard: Medium

Flammable liquids
Acute toxicity- oral, inhalation, dermal
Specific target organ toxicity- single exposure- eyes
Electric shock hazard
Burn hazard
Use of reactive, flammable, or toxic reagents
Use of hot plate and open flame

Effectiveness: Good

Results are clearly observable without guidance
Good connection from demo to course material
Time to results is high
Low failure rate
Contrast between behaviors of system is good (high)
Strong effects are observed

Difficulty: Medium

Simple procedures
Some concerted manipulation
Use of scientific equipment
Use of flammable or toxic reagents
Reaction of demos at non-standard conditions

Safety Precautions:

Eye protection required
Gloves required
Thermal gloves or tongs recommended
Use UL-approved three-prong plug and outlet
Absorbent materials on hand
ABC fire extinguisher on hand
Perform in well-ventilated area
Avoid inhalation or other exposure to mists or vapors

Class: Distillations, Matters and Mixtures, Separation Techniques

Division: General, Analytical Chemistry

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