Objective

To ascertain the solubility of crotonic acid in methanol, THF, benzene, ethanol, and toluene by NMR spectroscopy using dichloromethane as an internal standard.

Procedure

Saturated solutions of crotonic acid were prepare in methanol, THF, benzene, ethanol, and toluene solvents. The solutions were prepared by mixing together the solute and 1mL of the solvent into a vial. With subsequent additions of solute, with bouts of vortexing; which consisted of 2-3 minutes stints. Once the solution showed excess of solute, the vials were vortexed for 10 minutes. Solutions are then left to equilibriate. The supernatants from each saturated solutions was cautiously collected by decanting into separate vials. 100μL of the supernatants were dissolved into NMR tubes containing 700μLof deuterated chloroform (CDCl3) and 10μL of dichloroform; which is used as an internal standard for the NMR process. Proton NMR readings of the solutions are obtained with the use of a 300MHz instrument.

Results


Solvent
Solute
HNMR
Methanol
Crotonic acid
HNMR
THF
Crotonic acid
HNMR
Benzene
Crotonic acid
HNMR
Ethanol
Crotonic acid
HNMR
Toluene
Crotonic acid
HNMR

Using recently structured "Semi-automated measurement of solubility using NMR" spreadsheet, solubility of crotonic acid has been measured in five solvents.




Spreadsheet
Spreadsheet ONSC-EXP062B

Discussion


Based on the results from Exp064, I believe the DCM internal standard did evaporate. I have drawn up some new samples of crotonic acid in these solvents, and a new NMR analysis will be carried out using 1,2-dichloroethane as an internal standard with hopes to obtain better results.




Solvent
Solute
Internal standard
HNMR
Methanol
Crotonic acid
Dichloromethane

HNMR

THF
Crotonic acid
Dichloromethane

HNMR

Benzene
Crotonic acid
Dichloromethane

HNMR

Ethanol
Crotonic acid
Dichloromethane

HNMR

Toluene
Crotonic acid
Dichloromethane

HNMR


Conclusion

The solubility of crotonic acid has been determined in methanol, THF, benzene, ethanol, and toluene. The obtained data shows that crotonic acid is indeed capable of making 2M solutions for the Ugi product.

No solubility data existed for crotonic acid in literature using the Beilstein database

Log

(includes Observations)

2009-02-17

13:49 Added 1mL of methanol to a vial labeled "methanol" and capped it.
13:50 Added 1mL of THF solvent to a vial labeled "THF" and capped it.
13:52 Added 1mL of benzene to a vial labeled "benzene" and capped it.
13:55 Added 1mL of ethanol to a vial labeled "ethanol" and capped it.
13:56 Added 1mL of toluene solvent to a vial labeled "toluene" and capped it.
14:15 Added crotonic acid solute to "methanol" vial, and briefly vortexed the vial till no solute was seen dissolving into the solvent.
14:17 Added solute to "THF" vial and vortexed the vial briefly.
14:18 Added solute to "benzene" vial, and vortexed the vial till solute began to collect at the bottom of the vial.
14:20 Added solute to "ethanol" vial and vortexed the vial.
14:22 Added solute to "toluene" vial, and vortexed the vial till the solute no longer appeared to dissolve into solution.
14:25 It was observed that addition of crotonic acid to each solvent produced an endothermic reaction, as the temperature of the vials grew cold to the touch.
14:29 Vortexed all vials, checking periodically to see if the solutions became clear.
14:36 Added more solute to "benzene" vial and continued vortexing.
14:44 Added more solute to "THF", "methanol", and "ethanol" vials, as little solute was seen collecting within them.
14:49 Vortexed all vials for 10 minutes.
15:03 After the vials were vortexed, solute was observed to be undissolved at the bottoms of the vials, and they were left to equilibriate.
15:22 Supernatants from each vial was obtained and placed in new identically labeled vials.
15:25 5 NMR tubes and caps were cleanses using acetone, and then they were placed in a laboratory oven for quick evaporation of the solvent.
15:32 Added 700μL of deuterated chloroform to NMR tubes.
15:34 Added 10μL of dichloromethane to all NMR tubes.
15:37 NMR tubes were gently mixed.
15:42 Added 100μL of supernatant from "methanol" vial to NMR tube "1."
15:43 Added 100μL of supernatant from "THF" vial to NMR tube "2."
15:43 Added 100μL of supernatant from "benzene" vial to NMR tube "3."
15:44 Added 100μL of supernatant from "ethanol" vial to NMR tube "4."
15:55 Added 100μL of supernatant from "toluene" vial to NMR tube "5."
21:10 NMR tubes were mixed and HNMR readings for all samples was obtained.

2009-02-27

24:32 Added 1mL of methanol to a vial labeled "methanol" using a micropipette and capped it.
24:33 Micropipetted 1mL of THF into a vial labeled "THF" and capped it.
24:35 Added 1mL of benzene to a vial labeled "benzene" using a micropipette and capped it.
24:36 Added 1mL of ethanol to a vial labeled "ethanol" using a micropipette and capped it.
24:37 Micropipetted 1mL of toluene into a vial labeled "toluene" and capped it.
24:42 A spatula was cleaned using acetone.
24:48 Added crotonic acid to the methanol solvent and vortexed the vial. More solute was added to the vial if no undissolved solute remained after the stint of vortexing. This process was repeated until no more solute was observed to go into solution. It was observed that the process of mixing the solute and solvent together was an endothermic reaction, because the vials grew noticeably cold to the touch.
24:54 Added crotonic acid to the THF solvent and vortexed the vial. More solute was added to the vial if no undissolved solute remained after the stint of vortexing. This process was repeated until no more solute was observed to go into solution. It was observed that the process of mixing the solute and solvent together was an endothermic reaction, because the vials grew noticeably cold to the touch.
24:58 Added crotonic acid to the benzene solvent and vortexed the vial. More solute was added to the vial if no undissolved solute remained after the stint of vortexing. This process was repeated until no more solute was observed to go into solution. It was observed that the process of mixing the solute and solvent together was an endothermic reaction, because the vials grew noticeably cold to the touch.
1:02 Added crotonic acid to the ethanol solvent and vortexed the vial. More solute was added to the vial if no undissolved solute remained after the stint of vortexing. This process was repeated until no more solute was observed to go into solution. It was observed that the process of mixing the solute and solvent together was an endothermic reaction, because the vials grew noticeably cold to the touch.
1:06 Added crotonic acid to the toluene solvent and vortexed the vial. More solute was added to the vial if no undissolved solute remained after the stint of vortexing. This process was repeated until no more solute was observed to go into solution. It was observed that the process of mixing the solute and solvent together was an endothermic reaction, because the vials grew noticeably cold to the touch.
1:16 Vortexed all vials for a period of 10 minutes.
1:28 Vials were left to equilibriate.
1:30 5 NMR tubes were cleaned with acetone and evaporated in the laboratory oven.
1:38 5 NMR caps were cleaned with acetone and briefly evaporated in the oven.

2009-02-28

11:47 Decanted the supernatant from the saturated methanol solution into a new vial, labeled "sat. methanol."
11:49 Decanted the supernatant from the saturated THF solution into a new vial, labeled "sat. THF."
11:50 Decanted the supernatant from the saturated benzene solution into a new vial, labeled "sat. benzene."
11:51 Decanted the supernatant from the saturated ethanol solution into a new vial, labeled "sat. ethanol."
11:51 Decanted the supernatant from the saturated toluene solution into a new vial, labeled "sat. toluene."
12:03 Pipetted 700μL of deuterated chloroform into an NMR tube labeled "6" and capped it.
12:05
Pipetted 700μL of deuterated chloroform into an NMR tube labeled "7" and capped it.
12:05
Pipetted 700μL of deuterated chloroform into an NMR tube labeled "8" and capped it.
12:05 Pipetted 700μL of deuterated chloroform into an NMR tube labeled "9" and capped it.
12:06
Pipetted 700μL of deuterated chloroform into an NMR tube labeled "10" and capped it.
12:07
Pipetted 10μL of 1,2-dichloroethane into NMR tubes "6-10."
12:10 Pipetted 100μL of the supernatant from "sat. methanol" into NMR tube "6."
12:12
Pipetted 100μL of the supernatant from "sat. THF" into NMR tube "7."
12:13
Pipetted 100μL of the supernatant from "sat. benzene" into NMR tube "8."
12:14
Pipetted 100μL of the supernatant from "sat. ethanol" into NMR tube "9."
12:14
Pipetted 100μL of the supernatant from "sat. toluene" into NMR tube "10."
12:16 Briefly vortexed NMR tubes.
22:00 Obtained HNMR spectra of the solutions using 500MHz Varian instrument.


NMR tube sample #
Saturated solution solvent

6
methanol
7
THF
8
benzene
9
ethanol
10
toluene



Compound
Inchi Key
Inchi__
Crotonic acid
LDHQCZJRKDOVOX-NSCUHMNNBH
InChI=1/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/b3-2
Methanol
OKKJLVBELUTLKV-UHFFFAOYAX
InChI=1/CH4O/c1-2/h2H,1H3
THF
WYURNTSHIVDZCO-UHFFFAOYAI
InChI=1/C4H8O/c1-2-4-5-3-1/h1-4H2
Benzene
UHOVQNZJYSORNB-UHFFFAOYAH
InChI=1/C6H6/c1-2-4-6-5-3-1/h1-6H
Ethanol
LFQSCWFLJHTTHZ-UHFFFAOYAB
InChI=1/C2H6O/c1-2-3/h3H,2H2,1H3
Toluene
YXFVVABEGXRONW-UHFFFAOYAT
InChI=1/C7H8/c1-7-5-3-2-4-6-7/h2-6H,1H3
Dichloromethane
YMWUJEATGCHHMB-UHFFFAOYAG
InChI=1/CH2Cl2/c2-1-3/h1H2