Researcher

Marshall Moritz

Objective

To generate a solubility-temperature curve for 4-nitrobenzaldehyde in acetonitrile, chloroform, THF, and toluene
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Procedure

Solutions of known concentration of 4-nitrobenzaldehyde in mixtures of solvents were made by weighing out a known amount--1 gram--of solvent in a tared half-dram vial. Weighed amounts of 4-nitrobenzaldehyde were added to each vial. Each vial was tightly capped and parafilmed. Vials were set in a thermostated water:ethylene glycol bath until the bath reached 48.0C. The bath was cooled, and the temperature at which each vial showed precipitate was recorded to create a solubility-temperature curve. An NMR spectra was taken of 4-nitrobenzaldehyde in non-saturated solutions to verify the concentration of the vials and ensure there was no evaporation. The solutions were dissolved in 500uL of CDCl3 and the NMR was taken on the 500MHz Varian instrument.

Results





Spreadsheet Exp130

Discussion


Conclusion


Log

2009-07-22
9:34--Mixtures of THF, toluene, acetonitrile, and chloroform were made in vials 1, 2, 3, 4, and 5. Each vial had approximately 0.5 grams of solvent.
10:36--After the solvent(s) were added, each vial was tightly capped and set aside.
10:41--After inputting the values into the computer, it was discovered that vials 1, 2, 3, and 4 were all almost exactly the same comcentration.
10:50--Various amounts of 4-nitrobenzaldehyde were weighed and carefully added to each vial. After the 4-nitrobenzaldehyde was added, each vial was tightly capped.
10:54--Vials 6, 7, and 8 were made up with varying amounts of the four solvents. Vial 8 was composed of random values for the amount of each solvent and vials 1-7 had targeted values for each solvent.
10:58--Various amounts of 4-nitrobenzaldehyde were weighed and carefully added to each remaining vial. After the 4-nitrobenzaldehyde was added, each vial was tightly capped.
11:05--All vials were covered with parafilm to prevent any potential evaporation.

2009-07-27
9:44--All vials were added to a thermostated 3:2 water:ethylene glycol bath and the bath was set to 48.0C.
10:16--The bath reached 48.0C, left vials in bath to equilibrate. At 48.0C, all vials showed saturated solutions. The following procedure describes the duration of the experiment: the bath was set to a temperature and the lid was removed from the bath so that all vials could be observed as the temperature fell. When the bath reached the desired temperature, it was left to equilibrate for approximately 5 minutes. After again looking for saturated solutions, the temperature of the bath could be lowered again.
10:31--All vials had clear, unsaturated solutions. The temperature was turned to 45.0C.
10:40--Vial 1 showed precipitate at 46.8C and was removed from the thermostated bath.
10:45--All remaining vials were still unsaturated, The temperature was turned to 35.0C.
10:56--All remaining vials were still unsaturated at 35.0C and the temperature was turned to 30.0C.
11:02--All remaining vials were unsaturated. The temperature was turned to 27.0C. This process continuted until vial 8 was removed at -20.6C.
11:30--Solution from vial 8 was added to an NMR tube with 500uL of CDCl3.
11:35--NMR of vial 8 was taken on the 500MHz Varian instrument to verify concentration and ensure no solvent evaporation.

References

Solubility of 4-nitrobenzaldehyde in non-aqueous solvents

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