Researcher

Valentine Anyiam

Objective

Determination of the solubility of cinnamic acid in ethylene glycol, diethylene glycol and dichloromethane.

Procedure

Preparation of glycol solutions
Create two different mixtures, each containing 2g of cinnamic acid and one being filled with 11mL of ethylene glycol and the other being filled with 11mL of diethylene glycol. From there, choose one of the two methods described below:

Method A
Seal the solutions with a screw cap and place them within a water bath between 45-50C. After several minutes, take the solutions out of the water bath, invert and shake them a couple of times and then place them back in. Do this repeatedly after every couple of minutes. After the solutions have dissolved, take them out of the water bath and transfer the supernatants into a different test tube for each mixture. Then place these test tubes at room termperature. Then prepare these samples for NMR analysis.

Method B
Seal the top of both test tubes with para-film, poke a small hole in the center of each para-film and then suspend both test tubes within a bath of boiling water for several minutes. Then pipet out the supernatant into another test tube and keep this test tube at room temperature. Then prepare these samples for NMR analysis.

Preparation of Dichloromethane solution
Create another mixture with 2g of cinnamic acid and 11mL of dichloromethane within a test tube. Seal the top of this test tube with para-film, poke a small hole in the center of the para-film and then suspend it within a water bath between 40-45C for 1-2 minutes. Then pipet out the supernatant into another test tube and keep this test tube at room temperature. Then prepare the sample for NMR analysis.

Preparation of Samples for NMR Analysis
Pipet a small amount (less than 1mL) of CDCl3 into a small vial. Transfer a small amount (less than 1mL) of the supernatant into the vial and mix it with the CDCl3. Then transfer this mixture into an NMR tube and use this tube to take the NMR spectra of the sample.

Results

Solubility Sheet 1
The concentrations of cinnamic acid dissolved in ethylene glycol, diethylene glycol and dichloromethane were determined to be 0.382M, 0.862M, and 0.69M respectively from NMR analysis.
IMG_20120410_131755.jpg
Pic1: Samples 1 and 2 after being heated in boiling water and cooling at about 21C for a week

Discussion

Predicted
Method A was performed first during preparation of the glycol solutions containing cinnamic acid, however after heating the samples, transferring the supernatants of the samples into different test tubes and keeping these test tubes at room temperature, not much saturated solution seemed to have formed. Therefore the glycol solutions made within the first two test tubes were reused and applied with Method B in an attempt to achieve better results. After the solutions had heated, they were left to cool for a week. A week later, the test tube containing ethylene glycol, sample 1 seemed to have formed much precipitate, whereas a small amount of precipitate was also formed within the test tube containing diethylene glycol, sample 2, as shown in pic1. The NMR spectra of sample 2 was successfully analyzed and the results yielded a value of 0.862 M for the concentration of cinnamic acid in diethylene glycol. Technical difficulties arose when attempting to take the NMR spectra of sample 1. Another attempt will be made to analyze sample 1 at a another time. The NMR spectra of dichloromethane was successfully taken and results from the analysis yielded a value of 0.69 M for the concentration of cinnamic acid in dichloromethane. A second NMR sample of the ethylene glycol solution, sample 1, was prepared again later during the week and was successfully analyzed. The results yielded a value of 0.382 M for the concentration of cinnamic acid in ethylene glycol.

Conclusion

The solubility of cinnamic acid in ethylene glycol at 25C was determined to be 0.382M. The solubility of cinnamic acid in diethylene glycol at 25C was determined to be 0.862M. The solubility of cinnamic acid in dichloromethane at 25C was determined to be 0.69M. [New information discovered in EXP284, reveals these numbers to be unuseable due to the fact that these values were obtained after mixing the glycol solutions with CDCl3 solvent for NMR analysis. In EXP284, it was revealed that the glycol solutions are not fully miscible with CDCl solvent]

Log

2012-04-03

11:20- 2.007g of cinnamic acid were weighed out and poured into a test tube labeled test tube EG, sample1.
11:22- 2.002g of cinnamic acid were weighed out and poured into a test tube labeled test tube DEG, sample2.
11:24- 2.002g of cinnamic acid were weighed out and poured into a test tube labeled test tube DCM, sample3.
11:28- 11mL of ethylene glycol were added to the cinnamic acid in test tube EG. The test tube was then then capped with a screw cap.
11:31- The Buchi 461 Water Bath was turned on and set to 45C. The current temperature of the water bath was at 16C.
11:38- 11mL of diethylene glycol were added to the cinnamic acid in test tube DEG. The test tube was then capped with a screw cap.
11:43- Temperature of the Buchi 461 Water Bath is at 40C.
11:58- Temperature of the Buchi 461 Water Bath is at 49C. Test tubes EG and DEG were covered with para-film and then placed inside the water bath.
12:07- Temperature of the Buchi 461 Water Bath is at 50C. Test tube EG was taken out of the water bath, inverted and shaken a couple of times, and then placed back in.
12:14- Temperature of the Buchi 461 Water Bath is still at 50C. Test tube DEG was taken out of the water bath, inverted and shaken a couple of times, and then placed back in.
12:19- Test tube EG was taken out of the water bath, inverted and shaken a couple of times again, and then placed back in.
12:28- 11mL of dichloromethane were added to the cinnamic acid in test tube DCM.
12:33- Para-film was sealed on top of test tube DCM and a small hole was punctured within the center of the para-film.
12:36- A beaker full of warm water was set on top of a hot plate to be used as a water bath for boiling. The hot plate was turned to a setting of 2, and the temperature was at 34C.
12:40- Once the temperature reached 45C, the hot plate was turned off and test tube DCM was suspended within the water bath. A few seconds later, the dichlormethane mixture started to boil and the cinnamic acid started to dissolve.
12:41- Much of the solid remained on the top layer of the mixture. Test tube DCM was taken out of the bath at 45C. A few milliliters of the supernatant on the bottom layer of the tube was pipetted out and into a different test tube which was labeled test tube C. This test tube was then capped with a screw cap. Test tube DCM is to be discarded later.
12:43- Another beaker was filled with warm water to be used as a water bath at room temperature. The current temperature of this water bath was 27C.
12:45- Test tube C was placed inside the water bath with the temperature still at 27C.
12:48- Temperature of Buchi 461 Water Bath is still 50C. Test tube EG was taken out of the Water Bath. A few milliliters of the supernatant on top was poured into another test tube which was labeled test tube A. Test tube EG was set aside on a rack for the moment.
12:50- Test tube DEG was taken out of the Water Bath and a few milliliters of the supernatant on top was poured into another test tube which was labeled test tube B. Test tube DEG was set aside on a rack with test tube EG for the moment.
12:51- Test tubes A and B were placed within the room temperature water bath with test tube C. The temperature of this water bath was at 25C.
13:11- Temperature of room temperature water at 24C.
14:28- Test tubes A and B did not seem to have much saturated solution within them.
14:30- The hot plate below the water bath for boiling, was turned back on to a setting of 3. The temperature of the water bath was at 30C.
14:35- Temperature of the water bath for boiling was at 40C. Test tubes EG and DEG were placed within the water bath.
14:40- Setting of the hot plate was then increased to 9. The test tubes were left within the water bath so that the water could boil.
14:45- Temperature of room temperature water bath was at 20C.
14:52- Warm water was poured into the room temperature water bath until the temperature rose back up to 25C.
14:58- Less than 1mL of CDCl3 was pipetted into a small vial. Less than 1mL of the supernatant from test tube C was pipetted into and mixed within the test tube containing CDCl3. A few milliliters of this new solution were then pipetted into an NMR tube.
15:10- The NMR tube was taken down to the NMR machine on the first floor.
15:15- An NMR spectra was taken of the solution. The spectra was given the name exp277_c_hnmr. Data from exp277_c_hnmr was saved within a flash drive.
15:20- NMR data for exp277_c_hnmr was transferred onto a computer from the flash drive and converted into a jdx file.
15:25- The jdx file for exp277_c_hnmr was uploaded onto wikispaces and onto the solubility sheet.
15:40- Water bath for boiling had reached its boiling point and was turned off.

2012-04-10

13:17- Temperature of water bath containing test tubes EG and DEG was at 21C. Pic1 of samples 1 and 2 was taken. Much more precipitate seems to have formed within the solution in test tube EG, sample 1.
13:41- Less than 1mL of CDCl3 was pipetted into a small vial and was then mixed with less than 1mL of the supernatant from test tube DEG. This mixture was then transferred into a clean NMR tube which was capped with a red cap.
13:44- Another NMR tube was washed and cleaned with acetone and was then air dried before being used.
13:46- Less than 1mL of CDCl3 was pipetted into another small vial and was then mixed with less than 1mL of the supernatant from test tube EG. This mixture was then transferred into the NMR tube that was just cleaned and was then capped with a blue cap (NMR spectra may display traces of acetone).
14:06- An NMR spectra was taken of the sample containing diethylene glycol and was named EXP277B1_DEG. Data from EXP277B1_DEG was saved within a flash drive.
14:16- Problems arose when attempting to take the NMR spectra of the sample containing ethylene glycol, A1NMR1. Another attempt will be made to analyze the ethylene glycol solution at a another time.

2012-04-11

10:42- NMR data for EXP277B1_DEG was transferred from the flash drive onto a computer and converted into a jdx file.
10:45- The jdx file for EXP277B1_DEG was uploaded onto wikispaces and added onto the solubility sheet.

2012-04-13

10:30- Prepared a second NMR sample of the ethylene glycol solution, sample 1. Less than 1mL of CDCl3 was mixed with a slightly smaller amount of the liquid from sample 1.
10:36- Ran NMR spectra of the sample, A2NMR1.
10:38- Saved the data from A2NMR1 on a flash drive so that it could be uploaded on a computer.
10:44- Transferred data from A2NMR1 onto a computer and converted it into a jdx file.
14:00- Uploaded the jdx file for A2NMR1 onto wikispaces and added it onto the solubility sheet.