Phenolphathalein 2019.04.19

Kinetic of degradation of phenolphthalein in basic media work well as shown in the previous experiment.

Goal

Check the kinetic at different temperatures.

Solutions

• solution A: NaOH 0.3M in water
• solution B: water
• solution C: phenolphthalein 3.02 g/L in MeOH / EtOH

Results at RT

Spectro	Experiment	A	B	C
1	1	4 mL	0 mL	40 µL
3	2	3 mL	1 mL	20 µL
1	3	2 mL	2 mL	20 µL
3	4	1 mL	3 mL	20 µL

• Experiment 1
• Experiment 2
• Experiment 3
• Experiment 4

The data were processed online on the following page.

An exponential regression has been applied for the 4 experiments for the 20 first points (10 minutes).

Experiment	[NaOH]	k	rmsd
1	0.300 M	0.2254	0.002836
2	0.225 M	0.1785	0.001378
3	0.150 M	0.1061	0.002469
4	0.075 M	0.05185	0.000847

Results at 40

Spectro	Experiment	A	B	C
5	1	4 mL	0 mL	100 µL
5	2	3 mL	1 mL	20 µL
5	3	2 mL	2 mL	20 µL
5	4	1 mL	3 mL	20 µL

• Experiment 1
• Experiment 2
• Experiment 3
• Experiment 4

The data was processed online on the following page.

An exponential regression has been applied for the 4 experiments for the 20 first points (10 minutes).

Experiment	[NaOH]	k	rmsd
1	0.300 M	0.5597	0.01147
2	0.225 M	0.4466	0.00160
3	0.150 M	0.2945	0.00235
4	0.075 M	0.1721	0.00265

Results at 10

Spectro	Experiment	A	B	C
2	1	4 mL	0 mL	100 µL
1	2	3 mL	1 mL	20 µL
4	3	2 mL	2 mL	20 µL
6	4	1 mL	3 mL	20 µL

• Experiment 1
• Experiment 2
• Experiment 3
• Experiment 4

Spectro	Experiment	[NaOH]	k	rmsd
2	1	0.300 M	0.2707	0.00196
1	2	0.225 M	0.1276	0.00104
4	3	0.150 M	0.0961	0.00398
6	4	0.075 M	0.0605	0.00128