Exp210

=Objective= To measure the solubility of certain organic solutes in methanol and ethanol by evaporating the solvent from there homogeneous, saturated solutions under reduced pressure at ambient temperature. For a justification of this project see [|here]. =Procedure= A saturated solution of 13 solutes was prepared in six solvents. After centrifuging, 300uL of the supernatant was transferred to two pre-weighed half dram vials. The vials were weighed again and placed in a speed-vac for 10min. The temperature and the vacuum inside the speed-vac was noted. After evaporation for an initial 10min, the vials were weighed and placed back in the speed-vac. After another run for 10min, they were weighed. This process was performed for a third time and each the weights of the vials were recorded in a google spreadsheet. With the information obtained concentration and densities of the saturated solutions were calculated. =Results= [|Spreadsheet] media type="googlespreadsheet" key="p8qCqj9hchQA4Pkdpd_ZlPQ" height="400" width="950" =Discussion= The difference in the weights of the vials after the first evaporation run, when a dry solid was obtained indicated the amount of solid dissolved in the solvent. According to the Merck index the solubility of vanillin in ethanol is 1:2 vanillin:ethanol and according to the document on [|Sigma-Aldrich], its solubility in ethanol is 50 mg/ml. The solubility of Crotonic acid in ethanol at 25°: 52.5% w/w; acetone: 53.0% w/w; toluene: 37.5% w/w. ([|Merck Index 14th Edn], 2006-2008) //**How do these values compare to what you found, after converting to the same units? JCB**//


 * //In this experiment the solubility of phenanthrene-9-carboxaldehyde is extremely high in methanol (>3 M) but it has repeatedly been found to be much less soluble (for one example of many see EXP169). How is that possible? JCB - Possible sample mix-up.//**


 * Also the value for 4-pyrenebutanoic acid is >2M in methanol, which is inconsistent with the results in EXP173 JCB**

//**Based on this mix-up and the very low vanillin measurements - all results in this experiment are flagged as DONOTUSE. JCB**//

=Conclusion= Due to apparent sample mix up results from this experiment are not valid.

=Log=

2008-10-17
12:30 Weighed 26 (1-26) vials and recorded them in the spreadsheet.

2008-10-22
14:00 Made up saturated solutions of the all solid samples in methanol in one dram vials labeled **1-1 to 13-1**. Vanillin took about 6min of vortexing to form a saturated solution in 700uL methanol. Vortexed Phenanthere-9-carboxaldehyde for 5min when, just to make sure that anymore of the solid would not dissolve in the solvent. Pyrene-4-butanoic acid was vortexed for 2min. Boc-methionine formed a gel..the solution became so thick that it could not be vortexed any further. 15:00 Benzaldehyde soluble in methanol in all proportions...found out by transferring 100uL methanol in to a 1dram vial....further added benzaldehyde to this vial in all 5mL of the aldehyde was added to the vial...there was no separation of layers at any point during the addition. 15:30 Cenrtrifuged the one dram vials excluding boc-methoinine and benzaldehyde. 16:15 Transferred 300uL of the supernatant from each vial to pre-weighed half dram vials labeled **1a, 2a, 3a, 4a, 9a, 10a, 11a, 12a, 13a, 14a, 15a,** and **16a**, soon after transferring the supernatant the vials were tightly capped. 16:45 Obtained a pic of the solutions and supernatants //**(name the pic here then report it in the results section - for example 210-picA)**// 17:00 The vials were carefully weighed again without caps. 18:07 Placed the vials in a speed-vac. 18:08 Turned on the vacuum and the rotor of the speed-vac. Time, temperature and vacuum readings recorded during the run were 18:18 Turned off the speed-vac and removed the vials reweighed the vials. 18:15 After weighing the vials were tightly capped and a pic was taken of these vials.
 * Time || Vacuum Reading || Temperature C ||
 * 18:08 || 1Atm || 23.9 ||
 * 18:10 || 150mTorr || 24.8 ||
 * 18:15 || 140mTorr || 25.5 ||
 * 18:18 || 125mTorr || 25.8 ||

2008-11-05
11:30 The vials were uncapped and placed in the speed-vac for 10min 11:39 Temp -24.6C (//**shouldn't be negative JCB**//), Vac - 5T 11:40 Removed from the speed-vac and weighed 12:45 Placed the vials again in the speed-vac for 10min 12:55 Temp 26.1, Vac 5T; removed from the speed vac and weighed the vials.

2008-10-23 **//(this should be a separate experiment - only include runs as part of the same experiments that were done in parallel)//**
14:20 Weighed out 10 half dram vials and labeled them **27a, 28a, 29a, 30a, 35a, 36a, 39a, 40a, 41a** and **42a**. 14:35 Prepared saturated solutions of vanillin, phenanthrene-9-carboxaldehyde, 4-pyrene butyric acid, crotonic acid and 4-chlorophenyl acetic acid in ethanol (700uL) in 5 one dram vials labeled **27-2, 29-2, 35-2, 39-2, and 41-2**. 15:00 Centrifuged the one dram vials containg saturated solutions, and transferred 300uL of the supernatant to the half dram vials labeled **27a, 28a, 29a, 30a, 35a, 36a, 39a, 40a, 41a** and **42a**, these vials were tightly capped. 15:20 Half dram vials were weighed without caps. ( **27a, 28a, 29a, 30a, 35a, 36a, 39a, 40a, 41a** and **42a**.) 15:30 After weighing these vials they were tightly capped.

2008-11-05
1:30 The vials were uncapped and placed in the speed-vac for 10min 11:39 Temp -24.6C, Vac - 5T 11:40 Removed from the speed-vac and weighed 12:45 Placed the vials again in the speed-vac for 10min 12:55 Temp 26.1, Vac 5T; removed from the speed vac and weighed the vials.

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