Organic chemistry lab report - Simple distillation
Methods and Background
Data Acquisition/ Presentation
I. Relevant Equations
II. Simple Distillation of the Three Fractions
III. Gas Chromatographic Analysis of Simple Distillation Fractions
The purpose of this lab is to separate a mixture of ethyl acetate and butyl acetate using simple distillation to make three fractions: one containing pure EtOAc, one containing pure BuOAc, and one containing a mixture of both compounds. These fractions are then analyzed using gas chromatography to determine how efficient simple distillation is in separating the two liquids.
Boling point of any molecule is the temperature at which the pressure of the molecule equals the external vapor pressure. It depends on the molecular weight and the forces that hold the molecule together. Both EtOAc and BuOAc contain an ester group; however, BuOAc has higher molar mass than EtOAc. Hence, more energy is needed to break the intermolecular bonds and cause BuOAc to boil. Thus, BuOAc boils at 126oC whereas EtOAc boils at 77.1oC. Simple distillation takes advantage of the difference in boiling temperature at standard pressure conditions of the two volatile liquids.
In distillation, liquids are
The linear graph 1 is not a good representation of the separation of ethyl acetate and butyl acetate. Ideally slope of the graph should be divided into three parts. Area where fraction one was obtained should have a constant temperature. Area where fraction two was obtained should have a dramatic change in temperature indicated by a steep slope. This steep slope should signify the separation of BuOAc and EtOAc around 85oC, which is close to the boiling point of EtOAc (77.1oC). Area where fraction three was obtained should have a relatively constant temperature. This constant temperature should have been observed after 108oC.
Simple distillation separates less-volatile substance, like those that have lower equilibrium vapor pressure and high boiling point, from more-volatile substances. Thus, it isolates components of the mixtures into its pure form only if the differen
Gilbert, J.C., Experimental Organic Chemistry, Saunders Publishing, New York, 2006, 4th Ed, pp. 123-125; 127-130; 192-202.