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Learn how to propose a synthesis pathway for a specific compound, develop detailed lab procedures, propose spectral data, work efficiently in a team, and write a proposal.
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Lecture 12a Proposal
Introduction • Learning Goals • Research information in the literature using Scifinder, Reaxys, etc. that helps to propose a pathway to the synthesis of a compound assigned to you and your partner by the instructor. • Propose detailed procedures (which substitutes for your pre-lab minus the safety data) to be followed in the lab based on the work that was previously been performed in the field. • Propose spectral data and physical properties based on published data either by locating the actual data or something very similar. • Apply the lab techniques introduced in Chem 30XL courses. • Learn on how to work efficiently in a team (for most parts). • Writing a proposal. • Giving an oral presentation.
Structure of the Proposal I • Abstract • It briefly states the goal of the project (1-2 sentences). • Introduction • It shows that the students performed literature search and evaluated different procedures/approached for their feasibility to be used in Chem 30CL. • One alternate procedure for each step has to be shown and briefly discussed (the best strategy is a plan B here). • Discussion • Discussion the basic idea of the synthetic approach chosen for the lab. • It shows the key step of the mechanism of the reaction as carried out in the lab.
Structure of the Proposal II • Experimental • The exact amounts of reactants used (g and mol) • The exact amounts of solvent (mL) • The exact reaction conditions (temperature, time, etc.) • The exact techniques used (reflux, microwave, grinding, etc.) • A detailed account on how to monitor the progress of the reaction i.e., TLC (mobile phase, etc.) • Expected observations i.e., color change, evolution of gas, precipitation, etc. • A detailed account of the workup/isolation of the crude product • Purification steps • Recrystallization: solvent or solvent mixture (including the proposed ratio) • Flash chromatography: mobile and stationary phase • Include detailed safety information for all compounds used in the experiment
Structure of the Proposal III • Characterization • Melting point • Infrared spectroscopy • UV-Vis spectroscopy • 1H-NMR spectroscopy • 13C-NMR spectroscopy • Mass spectrometry • Note that the melting point cannot easily be extrapolated from other compounds because minor changes in the structure can have a significant impact on the way the molecules arrange in the crystal. • If the exact compound cannot be found, a very similar compound should be used as reference and the expected differences be rationalized in the infrared, NMR and UV-Vis spectrum of the compound because trends can be predicted in this type of data. • Spectra that have been simulated with Chemdraw, ACD software or Spartan are not acceptable here. Note that these programs cannot account properly for the ferrocene part.
Structure of the Proposal IV • Reference Section • Follow the same guidelines like the report • A copy of the key references (synthesis and spectroscopy) have to be attached to the proposal, properly labeled (numbered) and organized • Simulated spectra ≠ literature spectra
Limitations in the Lab • Note that there many limitations to the work performed in Chem 30CL • Time: four meetings with 3-4 hours each, this means that no overnight reactions are allowed, particularly those requiring reflux. • Hazards: chemicals that are very difficult to handle or are dangerous will not be provided in Chem 30 CL i.e., BuLi, LDA, LiAlH4, NaH, DMSO, chlorinated solvents, very dry solvents, etc. • Techniques: the lab is not able to provide a setup for strict inert gas techniques (Schlenk techniques), however basic inert gas technique i.e., nitrogen balloon is doable. • Cost: expensive catalysts i.e., Ru-based, etc. are not available.
Chemicals and Equipment • The following chemicals are usually provided: • Substituted benzaldehydes (X=Hal, OR, NO2, Alkyl, etc.) • Standard solvents i.e., hexane, ethanol, methanol, ethyl acetate, THF, diethyl ether, etc. • Compounds like potassium hydroxide, glacial acetic acid, Aliquat 336, Adogen 464, etc. • A microwave will be provided as well. If you plan to use it, make sure to get trained on it first by your TA.
Other Considerations • The proposal should only be seven (7!) pages long • Both group members have an obligation to contribute to the proposal (the in-lab work and the presentation) equally because they will receive the same grade for the proposal. • The proposal has to be submitted in a proper report folder like the Jacobsen paper, possess a proper title and the name and email addresses of the students on the front page. • The proposal has to be submitted in a proper folder to the instructor by February 26, 2016 at 12:00 pm. • The proposal (one per group) has to be submitted to www.turnitin.com by February 26, 2016 at 12:00 pm as well. Failure to do so will result in an automatic 5-point deduction. • The experimental work for the project will be conducted during week 9 (March 1 through March 4). The students generally will only be allowed to attend their own lab meeting! Only one student of each group will be allowed in the lab at a given time. • The oral presentation showing the results will take place on March 8, 2016 (starting at 1 pm probably) in YH 6086 (tentatively). You and your partner have to sign up for it in the instructor’s office asap after the instructor announce that the projects are available.