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Duc Chau Chem 237-517 TA: Alexander Holter Phase Transfer Catalysis The purpose of this lab was to see the effect of a phase transfer catalyst on a Sn2 reaction in dichloromethane. The methods were used during the experiment were isolation of the product by using TLC techniques and see the product under UV light. In this experiment, the naphtholate anions was move from aqueous to organic phase by using the phase transfer catalyst benzyl tri-n-butylammonium chloride. This is necessary for the reaction with allyl bromide to occur. The reaction was completed in 30 minutes. TLC was used to measure the amount of product formed throughout the experiment. Four-time intervals were measured on TLC plates including one at 0 minute, 5 minutes, 15 minutes, and 30 minutes. The measurement of Rf values and distance travelled are measured and recorded down below in Table 1. Sample # Solvent front T=0 T=5 T=15 T=30

Distance Travelled (cm) 3.2 2.9 1.7 1.7 0

Rf values 0.9 0.53 0.53 0

The sample at 0 minute had the largest Rf value of 0.9. The Rf value was found by using formula RF=(DX/DY). This shows that at sample 0 is not the spot for 2-napthol ether. Although the Rf is significantly larger than at t=15 and t=30, but the Rf is not constant. Therefore, this is due to errors. For the second TLC plate, syringe was used to extract the reaction vial from the bottom dichloromethane layer and dried with 0.5 grams of anhydrous calcium chloride. For the second plate, the same process was repeated. However, this part of the lab was not done in-lab, but the data was given on Ecampus. Below is a table of the recorded data from Ecampus including calculated Rf value.

Sample Vial 1 2 3 4 5

Rf 0 cm 0 cm 0.94 cm 0.30 cm, 0.95 cm 0.35 cm

Sample vial number 3 was proven to have the largest Rf value at 0.95 cm. Sample 4 was then used to obtain an IR spectrum because of its large value of RF value and its strongest TLC spot. Furthermore, it stayed constant throughout the reaction. Additionally, vial 3 and 4 have similar Rf value. Therefore, it is right to assumed that those two vials contained the 2-naphthol product. The mass of

fraction 3 and 4 were given to calculate the percent yield of the 2-naphthol product. Furthermore, judging from IR graph that was given on ecampus, fraction 4 IR spectrum have a very similar peak to 2naphthol at 3381 for fraction 4 while 3256 for 2=naphthol.

𝐴𝑐𝑡𝑢𝑎𝑙 𝑦𝑖𝑒𝑙𝑑

Yield of product= 𝑇ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑦𝑖𝑒𝑙𝑑 ∗ 100 Fraction 3=

0.030 𝑔𝑟𝑎𝑚𝑠 0..004 𝑔𝑟𝑎𝑚

Fraction 4= =

∗ 100 = 13.33%

0.030 𝑔𝑟𝑎𝑚𝑠 =6.67% 0..002 𝑔𝑟𝑎𝑚

There are many errors in this lab. One would be that the solvent was stirred too fast. Second, when putting the TLC plate into the chamber, it was moving around too much. Therefore, causing a disturbance on the TLC plate causing the solute not moving properly as shown in t=30 minutes that the solute did not move from its original line. Next time let the TLC plate sit in the chamber without any disturbance will help to avoid this problem in the future. However, this lab is determined to be successful in achieving the given objective of using a phase transfer catalyst to result in a Sn2 reaction in dichloromethane and observing the results....