Hieu Nguyen


To recrystallize salicylic acid [incorrect way to link to ChemSpider - see other experiments for examples JCB] in 1-octanol by using the vortex, centrifuge and pentane to wash the crystals. Specifically, the purpose of this method is to get a pure salicylic solid and a better percent yield.








12:10--Labeled 3 empty 10 mL test tube with screw cap as H1, H2, H3.
12:15--Measured the mass of an empty vial which is 11.7555 g and placed each test tube in the vial (because I cannot place the test tube on the analytic balance without using a vial to balance the test tube, therefore I measure the mass of both of the test tube and the vial and then subtracting the mass of the vial which is constant to calculate the mass of each test tube).
12:18--Transferred about 0.25 g of salicylic acid to each test tube using the analytic balance and the weighing paper.
12.21--Transferred 1-octanol to each test tube using a Pasteur pipet.
13:01--Heated all 3 test tubes in a hot bath using a hot plate at 130 Celsius Degree.
13:05--Observed that the compound is gradually dissolving.
13:07--All the solid is dissolved, placed all 3 test tubes in the Vortex Genie-2 to totally mix the solution and then immediately put them in the icebath.
13:25--Observed that there is only crystals formed in test tube H1.
13:30--Took off test tube H1 and placed it in a 6-holes centrifuge.
13:31--Turned on the centrifuge.
13:40--Turned off the centrifuge and took off the test tube.
13:42--Pipeted off as many supernatant as you can from the test tube without taking any crystals out of the test tube.
13:45--Washed the crystals with 1 mL of pentane (1st).
13:46--Vortex the test tube at level 4 for 30 seconds.
13:48--Centrifuge it again.
13:50--Took off the test tube from the centrifuge.
13:52--Pipet off the liquid in the test tube as many as you can.
13:53--Washed the crystals with pentane (2nd).
13:54--Vortex the test tube at level 4 for 30 seconds.
13:55-- Centrifuge it again.
13:56--Took off the test tube.
13:57--Pipet off the supernatant and wash the crystals with pentane (3rd).
13:58--Vortex the test tube at level 4.
13:59--Centrifuge it again.
14:00-Took off the test tube.
14:02--Check spot on TLC plate, no visible spot detected.
14:10--Observed that some crystals stick on the inner side of the test tube.
14:20--Used scupula to make all salicylic crystals come to the bottom of the test tube.
14:23--Pipet off as much liquid as possible.
14:25--Put the test tube on the hot bath at 120 Celsius Degree to make all remained pentane evaporate.
14:28--Used scupula to spread the crystals in the test tube to make the liquid easier to evaporate because the crystals were still wet after 3 minutes of heating.
14:29--Put the test tube in the hot bath at 115 Celsius Degree and let the crystals dry totally after 4 minutes of heating in a hot bath.
14:58-- Measure the melting point of the salicylic crystals to check the purity of the crystals.
15:02--Observed that the crystals started to melt at 159 Celsius Degree.