Uploaded July 2020 | Updated September 2026, 2 weeks ago
In this demonstration, the kinetics of a condensation reaction will be studied using a piece of equipment called HPLC. This stand for ‘High Pressure Liquid Chromatography’. This will be controlled remotely from my desk at Rugby School.
In this experiment, we will react an amine, isopropyl analine, with a carboxylic acid, propanoic acid. This reaction will be catalysed using a special chemical called a coupling agent. The one we will be using is called HATU. An acid chloride cannot be used in this case as it would react with the chromatography column.
You should be able to show that the reaction is first order with respect to the amine. You can do this in two ways:
1. Draw a graph of amine concentration vs time. Show that the half-life of amine concentration over time is constant.
2. Draw a graph of rate vs amine concentration. This should be a straight line through the origin with a positive gradient. This gradient is equal to the rate constant for the reaction.
It is easy to see how this experiment could be extended. For example, instead of using only one acid, several acids could be added at the same time to the same reaction mixture. This would be a convenient way in which to compare the reactivity of several different acids simultaneously.
Calibration Data:
Conc (mM); Amide Peak Area; Amine Peak Area
2.5; 1192; 1009
5; 2525; 2026
10; 5020; 4159
20; 9768; 7832
25; 11972; 9724
Condensation Experimental Data:
Time (s) Amine Peak Area Amide Peak Area
0; 9141; 0
279; 7047; 2997
525; 3904; 6213
763; 2556; 7559
998; 1886; 8404
1235; 1428; 8890
1472; 1125; 9221
1708; 898; 9383
1945; 734; 9579
2184; 600; 9666
2423; 501; 9753
2662; 426; 9893
In this demonstration, the kinetics of a condensation reaction will be studied using a piece of equipment called HPLC. This stand for ‘High Pressure Liquid Chromatography’. This will be controlled remotely from my desk at Rugby School.
In this experiment, we will react an amine, isopropyl analine, with a carboxylic acid, propanoic acid. This reaction will be catalysed using a special chemical called a coupling agent. The one we will be using is called HATU. An acid chloride cannot be used in this case as it would react with the chromatography column.
You should be able to show that the reaction is first order with respect to the amine. You can do this in two ways:
1. Draw a graph of amine concentration vs time. Show that the half-life of amine concentration over time is constant.
2. Draw a graph of rate vs amine concentration. This should be a straight line through the origin with a positive gradient. This gradient is equal to the rate constant for the reaction.
It is easy to see how this experiment could be extended. For example, instead of using only one acid, several acids could be added at the same time to the same reaction mixture. This would be a convenient way in which to compare the reactivity of several different acids simultaneously.
Calibration Data:
Conc (mM); Amide Peak Area; Amine Peak Area
2.5; 1192; 1009
5; 2525; 2026
10; 5020; 4159
20; 9768; 7832
25; 11972; 9724
Condensation Experimental Data:
Time (s) Amine Peak Area Amide Peak Area
0; 9141; 0
279; 7047; 2997
525; 3904; 6213
763; 2556; 7559
998; 1886; 8404
1235; 1428; 8890
1472; 1125; 9221
1708; 898; 9383
1945; 734; 9579
2184; 600; 9666
2423; 501; 9753
2662; 426; 9893
