Objective

To familiarize myself with the UV/VIS method of determining solubility, by obtaining the extension coefficient of 4-chlorobenzaldhyde.

Procedure

Weighed out 367mg (+or-) 1mg of 4-chlorobenzaldehyde into a one dram vial. Charged vial with methanol and vortexed for approxiametly for 20s. Used a transfer pipet to transfer saturated solution into a 10ml volumetric flask. Charge vial with more methanol and vortexed again to dissolve rest of the solute. Pipetted solution into 10ml flask. Repeated this sequence until all of the solute was dissolved. Added additional methanol to flask until 10ml was achieved. Created 3 dilutions of stock solution, 1:10, 1:100, 1:1000, made in that order. Each dilution was made by taking 1ml of previous solution and charging a 10ml volumetric flask with it. Then each flask was brought up to 10ml with the addition of methanol. Solutions were ran on a perkin-elmir UV/VIS instrument starting with the most dilute.

Results

UV/VIS data will be put on in the coming week. Please make sure to add the UV/Vis spectrum onto ChemSPider for future reference (http://www.chemspider.com/docs/Uploading_Spectra_onto_ChemSpider.htm). AJW.
However the extension coefficient was found to be 8970 mol-1 cm-1, at a wavelength max of 244nm.
The published value for max wavelenght was reported to be 255 nm. The extension coeffecient is also reported in the same paper to be 19100 mol-1 cm-1.

Discussion



Log

2008-11-20

13:30 Weighed out 376mg of 4-chlorobenzaldehyde into a tared one dram vial.
13:35 Charged one dram vial with methanol. Vortexed for 30s.
13:40 Cleaned out 4, 10ml volumetric flasks by rinsing with methanol.
13:45 Pipetted dissolved solution into a 10ml flaskA.
13:50 Added more methanol into one dram vial, vortexed for 30 seconds.
13:52 Pipetted dissoved solution into 10ml flaskA.
13:54 Added more methanol into one dram vial, vortexed for 30 seconds.
13:56 Pipetted final amounts of solution into 10ml flaskA.
13:57 Rinsed one dram vial with methanol.
13:58 Transferred to flaskA.
14:00 Brought flaskA to 10ml with methanol.
14:02 Labelled 3, 10ml volumetric flasks, 1:10, 1:100, 1:1000, B, C, and D, respectively.
14:05 Pippetted 1ml of stock solution from flaskA into flaskB.
14:08 Brought flaskB to 10ml with methanol.
14:09 Inverted flaskB many times.
14:13 Pipetted 1ml of flaskB solution into flaskC.
14:16 Brought flaskC to 10ml with methanol.
14:17 Inverted flaskC many times.
14:20 Pippetted 1ml of flaskC into flaskD.
14:23 Brought flaskD to 10ml with methanol.
14:24 Inverted flaskD, many times.
15:15 Ran the 1:1000 dilution on UV/VIS. name file here - for example 12D-UV1 JCB
15:20 Saved information onto flash drive.