Qualitative Analysis - Aldehydes In this assignmentyou will be given an unknown compound for which you will need to determine its chemical structure. This unknown will contain an aldehyde functional group but may also contain other functional groups as well. The tools you will have available to perform this analysis include 1S functional group testsIR and NMR spectroscopy, plus other useful data
1. Stuart Virtual Chemical and select Qualitative Analysis - Aldehyders from the list of assignments in the electronic workbook. After cmtering the organic laboratory, go to the stockroom by clicking inside the Stockroom window. Next, select a round bottom flask and place it on the cork ring on the stockroom counter. On the reagent shelf you will find two or more compounds that serve as practice unknowns and another bottle that is your assigned unknown. The practice unknowns can be used to gain proficiency with the functional group tests and IR and NMR spectra interpretation. When you are ready to analyze your unknown, click on the unknown bottle and add it to the round bottom flask. Click on the green Return to Lab arrow to rectum to the laboratory.
2. The round bottom flask containing the unknown should now be on the cork ring on the lab bench. The boiling point and C-H analysis for the unknown are listed on the chalkboard. If the unknown is a solid, the melting point can be measured by clicking on the melting point apparatus by the reagent shelf and dragging the melting point tube to the unknown in the Task. The melting point will be displayed on the red LED, which can be enlarged by mousing over the apparatus. It will also be useful to know the polarity of the unknown by performing a TLC measurementRecord all of this information in the data table below. Data Table CH Analysis Meling Point co Boiling Point (o TLC (R)
3. To collect an IR spectrum of your unknown, click on the IRS spectrometer located underneath the laboratory clock and drag the salt plate icon to the flask on the lab bench. A window containing the IR spectrum for your product should now open. Identify the relevant peaks in the IR spectrum and record the position and associated functional group for each in the IR table below. The IR spectrum can also be saved to the lab book for later analysis. IR List position (em ")& functional group 4.
4. To collect a 'NMR spectrum of your unknown, click on the NMR magnet located to the right of the chalkboard and drag the NMR sample tube to the filesk on the lab bench. A window containing the NMR spectrum for your unknown should now open. You can zoom into various portions of the AMR spectrum by clicking and dragging over the desired area. The Zoom Oar button is used to zoom back out to view the full spectrum dentify all of the peaks in the NMR spectrum and record the chemical shil, the splitting, and the number of hydrogens for cash peak in the AMR table on the reverse side. The NMR spectrum can also be saved to the lab book for later analysis