Researcher

Sozit Kurtu

Objective

To determine the solubility of cinnamic acid in methanol by making solutions of known concentration at slightly below room temperature (~20-22C) in order to support or refute the results obtained in experiments 176 and 177.

Procedure

Results

Calculations
Measurements
EXP178-1.jpg
EXP178chart1 - Scatter plot of flask size (mL) vs. measured concentration (M) of the 1.3M solution.

EXP178-2.jpg
EXP178chart2 - Scatter plot of flask size (mL) vs. measured concentration (M) of the 1.4M solution.

EXP178-3.jpg
EXP178chart3 - Scatter plot of flask size (mL) vs. measured concentration (M) of the saturated solution.

Flask Size (mL)
1.3M
1.4M
saturated
10
1.32
1.38
-
5
1.29
1.44
1.203
2
1.35
1.41
1.280
1
1.32
1.40
1.349
mean
1.32
1.40
1.277

rsz_EXP178pic1.JPG
EXP178pic1 - Right to left: 1.3M, 1.4M, 1.5M solutions directly after sonication.

EXP178pic2.JPG
EXP178pic2 - Right to left: 1.3M, 1.4M, 1.5M solutions ~24hrs after sonication.

Discussion

There was error up to +/- ~4%, which may be indicative of inherent error in volumetric flask usage. Unfortunately, the experiment was interrupted before measurements could be taken a second time. .

Conclusion

While the solubility of cinnamic acid in methanol was found to be slightly higher than reported, it still agreed with literature values.

Log

2010-09-21

11:41 - Measured cinnamic acid for 1.3M, 1.4M, and 1.5M as per the calculations above, by taring the flask and inserting cinnamic acid directly into flask using a narrow spatula. Did not fill to volumetric line due to errors that might occur during sonication. Sonicated to dissolution and then filled to avoid overshooting the line (as dissolution would change the volume), as noted below as 'sonicated flask X' and 'added methanol to flask X'.
12:08 - Added methanol to flask 1.
12:10 - Sonicated flask 1.
12:12 - Added methanol to flask 1.
12:13 - Sonicated flask 1.
12:17 - Heated flask 1 for 1.5 min at 40C to hasten dissolution.
12:19 - Sonicated flask 1.
12:22 - Removed flask 1. Sonicated flask 2.
12:24 - Added methanol to flask 2.
12:25 - Lab was measured to be 20C. Sonicated flask 2.
12:30 - Removed flask 2. During this procedure, it was not necessary that flask 2 be heated beyond trivial heating during the sonication process.
12:35 - Sonicated flask 3.
12:37 - Added methanol to flask 3.
12:38 - Sonicated flask 3.
12:40 - Removed flask 3. During this procedure, it was not necessary that flask 2 be heated beyond trivial heating during the sonication process.
12:44 - Put flasks 1, 2, and 3 in 22C bath. All flasks were translucent yellow prior to cooling, indicating dissolution.
13:37 - Removed flasks from bath. Tubes 1 and 2 remained clear. Tube 3 contained precipitate. See EXP178pic1.

2010-09-22

10:53 - Took picture of flasks that had been stored overnight.
10:55 - Measured temperature of lab and foudn it to be 22C..
10:57 - Weighed 10-mL flasks 1 and 2. Excluded flask 3 from the 10-mL measurement, because after decanting supernatant, I was not confident of 100% transfer. However, sample 3 was used for subsequent measurements.
11:05 - Weighed 5-mL flasks.
11:07 - Transfered to 5-mL flasks and weighed them.
11:16 - Repeated process with 2-mL and 1-mL. Because there were only 2 1-mL flasks, I cleaned and reused flask 1 for sample 3.
11:31 - Cleaned flasks and dried them using nitrogen.
11:49 - Measured weight of methanol in each flask.