Distillation Using Gas Chromatography

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Distillation is a method used to separate compounds based on their differences in boiling points. This technique is favored when the compounds one wants to analyze have significantly different boiling points. During distillation, liquids are separated by heating, with the more volatile, lower boiling point liquid evaporating first. The vapors are then transported to a cooler part of the distillation column, and then condensed back to liquid. In distillation, the more volatile liquid with the lower boiling point would be collected first, followed by the liquid with the second lowest boiling point, and so on. To achieve good separation, a low rate of distillation and a high reflux ratio is needed. Simple and fractional distillations were used…show more content…
Using gas chromatography, the liquid mixture was identified and analyzed. For simple distillation, the mole fractions for hexane in vials 1, 2, 3, and 4 were 0.7533, 0.6366, 0.5459 and 0.2668, respectively. The mole fractions of heptane were 0.2467, 0.3634, 0.4542, and 0.7332, respectively. For fractional distillation, the mole fractions for hexane were 0.9116, 0.7916, 0.6759 and 0.03511, respectively. The mole fractions for heptane were 0.08838, 0.2084, 0.322687, and 0.96489. Fractional distillation resulted in better separation than simple distillation because it had a lower rate of distillation, greater insulation and higher reflux than simple distillation. The setup for simple distillation was easier than the setup for fractional distillation. This distillation method also had faster distillation times than fractional distillation. Simple distillation is best used when the liquids in a liquid mixture have large boiling point differences. However simple distillation results in poorer separation of the two liquid mixtures due to lack of insulation of the distillation column. Fractional distillation takes longer to perform than simple distillation mainly because setting up the fractionating column takes more time. Since there are more condensation cycles in fractional distillation than in simple distillation, the distillation process is slower. The advantage of fractional distillation is that better separation of liquids is achieved. Gas Chromatography was used to identify the unknown liquid components. Gas Chromatography is a sensitive technique that requires care to properly execute. If the injection of liquid into the micro syringe was too large, then it would be difficult to determine the amount of liquid sample in the fraction. The advantage of using gas chromatography was its quick speed and accuracy in analyzing the amount of each compound in a sample. A limitation to using gas chromatography for

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