Synthesis of Tetraphenyloporphyrin and Its Purification by Column Chromatography Essay

Submitted By Tammy7724
Words: 576
Pages: 3

 In this lab, we use the silica TLC plates to check how the TPP spot moves from the starting line.
 We started heating the vial to 170 degree and inject the benzaldehyde and heated until 180 degree then inject the pyrrole and raised the temp. to 250 degree and heated for 15 mins. After 15 min. cool the vial to room temp. Then we add 0.3 ml of methylene chloride to the vial to dissolve the black product from the cap and wall.
 We performed a TLC test using 14:1 hexanes: ethyl acetate. We draw a starting line on the plate, and spot the plate. Wait for the spot to dry and put it in the solvent under the hood. After the TPP separate take out the TLC plate and draw the solvent mark and measured the length.
 We prepared the pipette to purify the mixture. We put a little cotton in the bottom and added the layer of sand, then the silica gel about 2/3 full and a thin layer of sand on top of it. After that we started to put our solvent until it drips out from the column and collect the liquid to 4 tubes (20 drops each) and start the metallation of TPP.
 After that we did another TLC test, first mix half of the porphyrin product with 10 drops cupric acetate solution. Shake it and heat it to 40 degree under the hood. Then spot the mixture on the plate and use 14:1 hexanes: ethyl acetate as the solvent run the test and measure the length and find the Rf values.
The experience worked and we got: Rf = 0.31 (total move 3.6 cm/ spot move 1.1 cm) for the first test and Rf = 0.38 (total move 3.2 cm/ spot move 1.2 cm) for the second test. Error
When we heat up the mixture of porphyrin and cupric acetate we did not cover the tube right away and I think some of the mixture evaporates in to the hood so the 2nd test had some difficulty to find the right result. In addition, when we heated the benzaldehyde and pyrrole mixture the temperature did not heat up to