Simple and Fractional Distillation of Methanol and 1-Butanol
Organic Chemistry 250
Sarah Perez
Purpose
The purpose of this lab is to demonstrate the separation of a two-component liquid mixture based upon their difference in boiling point. The separating efficiency of simple and fractional distillation will be compared.
Introduction
Distillation is a laboratory technique used for separating and purifying liquids. There are two types of distillation of which both were used during this lab. Fractional distillation and simple distillation. Distillation basically separates the boiling points of two or more liquids, using heat. The liquid with the lower boiling point will evaporate first causing the vapor to pass through the condensing column where it will condense and trickle into the vials provided, this will be the methane. Heating further will cause the mixture to then trickle into vial two. And lastly butane which has the highest boiling point into vial three. The setup for a simple distillation and fractional distillation are very similar with one exception. Fractional distillation requires a special condenser which has coil in it and cools the mixture. Simple distillation is shown in Figure 1. Figure-1 SIMPLE DISTILLATION
A simple distillation apparatus consists of a boiling flask (round-bottom flask) attached to an adapter holding a thermometer (to determine the boiling temperature of the liquid). The adapter connects to a condenser into which cold water is constantly passed through. The condenser leads into a collection flask, or a vial, where the distillate will be collected.
The setup for fractional distillation is slightly different. Fractional distillation is essentially the same as simple distillation except that a fractionating column is placed between the boiling flask and the condenser, figure-2. This column was filled with coil, which improves the separation between the liquids being distilled. The liquids with a higher boiling point will tend to push towards the top of the fractionating column, while lower boiling liquids will stay towards the bottom, giving a better separation between the liquids. Fractional distillation takes longer continuously re-evaporate the liquid in the fractioning column. Figure -2 FRACTIONAL DISTILLATION
PROCEDURE
I.
i. Place the thermometer below the distillation head. ii. Add the liquid solution, no more than 2/3 volume in the round bottom flask. iii. Add 1-2 boiling chips to the flask. iv. Do not distill to dryness.
II. Add 30 mL (1:1) of methanol and 1- butanol in a 100 mL round bottom flask. The rate of distillation should not be greater than 1 mL/min: one drop/sec.
III. There will be 3 vials to collect the distillate:
A. Methanol at a low temperature
B. The mixture
C. 1-Butane at a high temperature IV.
D. Record the time, temperature, and test the GC after each collection.
NOTE: 2 experiments were done separately for the simple and fractional distillation.
Data
The simple distillation was just that, simple. The three vials needed for collection were filled in less than half the time that fractional distillation was completed. The temperatures were reached quicker therefore distillated quicker.
The fractional distillation on the other hand took a lot longer. Personally my experiment took even longer than normal because of faulty equipment, so to achieve all the vials the distillation took approximately 3 hours.
The temperature for methanol was 49◦ C, and it took approximately 2 hours and 25 minutes to collect the distillate.
The temperature for the mixture was 149◦ C, and it took approximately 2 hours and 40 minutes to collect distillate.
The temperature for 1– Butane was 240◦C, and it took about 3 hours to collect the distillate.
The GC was tested for collection and the peaks are all included.
Questions
In fractional distillation, liquid can be seen from the bottom of the distilling flask. What affect does this returning
