EXP069-HaeJi Choi


To determine the solubility of 2-chloro-5-nitrobenzaldehyde and octadecyl amine in 5 different solvents. The solvents are methanol, ethanol, THF, acetonitrile, toluene by NMR.


Saturated solutions of 2-chloro-5-nitrobenzaldehyde and octadecyl aminewere made with methanol, ethanol, THF, acetonitrile, toluene. After the last addition of solute to the solvents, they were vortexed for 10min each to saturate the solutions. After centrifuging the vials the supernatants (100uL) were placed into NMR tubes containing 700μl of CDCl3. Proton NMR of the solutions were obtained on a 500MHz Varian Unity Inova instrument. The solubility of the isocyanide and the amine was determined using SAMS.

[Following on from JCB's remarks below, the same issue keeps coming up with each participant: how do you know that you have a saturated solution? Where are the data collected to verify saturation, what procedure did you use to prepare sat solns and was that procedure standard throughout all your work? At what temperature was the work conducted? What mixing times were tested? These are not pointless nitpicks, they are central to the project. BH]


2-chloro-5-nitrobenzaldehyde [also take a spectrum in CDCl3 and upload to ChemSpider JCB]
1 -methanol + 2-chloro-5-nitrobenzaldehyde - HNMR
2 -ethanol + 2-chloro-5-nitrobenzaldehyde - HNMR
3 -THF + 2-chloro-5-nitrobenzaldehyde - HNMR[too many peaks for this to be true JCB]
4 -acetonitrile + 2-chloro-5-nitrobenzaldehyde - HNMR
5 -toluene + 2-chloro-5-nitrobenzaldehyde - HNMR
octadecyl amine
6 -methanol + octadecyl amine - HNMR
7 -ethanol + octadecyl amine - HNMR
8 -THF + octadecyl amine - HNMR
9 -acetonitrile + octadecyl amine - HNMR
10 -toluene + octadecyl amine - HNMR


From the HNMR of sample #3, (THF + 2-chloro-5-nitrobenzaldehyde ) it is obvious that the sample has been contaminated with toluene (singlet at 2.33ppm and multiplets between 71.1-7.3ppm). Therefore the solubility obtained for this sample has been discarded.




11:41 Made up saturated solutions of 2-chloro-5-nitrobenzaldehyde in methanol, ethanol, THF, acetonitrile, and toluence.
11:49 Vortexed sample #1,2,3,4, and 5 for 10 minutes and added more solute if the solution was clear.
12:05 Made up saturated solutions of actadecyl amine in methanol, ethanol, THF, acetonitrile, and toluence.
12:16 Vortexed sample #6,7,8,9, and 10 for 5 minutes.
12:28 Added more solvents into sample #1,2,3, and 4 and vortexed for a minute.
12:35 Vortexed sample #1,2,3, and 4 for 10 minutes.
12:45 Placed it for 30 minutes.[You don't know that at 12:45 JCB]
13:08 Vortexed sample #2 for a second to make sure there's enough solvent in sample #2.
14:50 Centrifuged the saturated solutions sample #1,2,3,4,5, and 6 for 10 minutes.
15:00 Centrifuged the saturated solutions sample #7,8,9, and 10 for 3 minutes.
15:03 Added some acetronitrile in the sample #9.
15:05 Vortexed the sample #9 for 10 minutes.
15:15 Centrifuged the sample #9.
15:25 Poured out the liquid of the sample #1,2,4,5,6,8,9, and 10 into vial 1a,2a,4a,5a,6a,8a,9a, and 10a.
15:28 Added more toluene into the sample #3
15:29 Vortexed the sample #3 for 1 minute and let it sit for 15 minutes.[This breaks the 10 min vortex upon last addition rule JCB]
15:30 Added more ethanol to the sample #7 and vortexed for 5 minutes. [This breaks the 10 min vortex upon last addition rule JCB]
15:34 Added CDCL3 (700μl) into tubes labeled 1 through 10.
15:38 Centrifuged the sample #3 and #7 for 5 minutes.
15:39 Poured out the liquid of the sample #3 and #7 into vial 3a and 7a.[Not physically possible to centrifuge for 5 min then pour out one min later JCB]
15:40 Obtained a picture of the solutions.[Name the pics here, for example 69-pic1 JCB]
15:48 Added 100uL of the supernatant into 700μl and shaked it well for 5 minutes.
15:59 Obtained HNMR of the solutions.