Oil baths are typically employed as heating elements when the temperature must be carefully controlled and when the reactants are flammable (and thus an open flame is not advised). In this case, an oil bath was likely employed since THF is flammable. The oil is heated on a hot plate and the temperature is monitored using a thermometer. Specialized equipment may include an immersion heating circulator, which evenly circulates heat throughout the vessel. Materials used in oil baths include medical paraffin, glycerol, silicon oil, cottonseed oil, or mineral oil. Disadvantages of using an oil bath include potentially spilling or spattering the oil and the extended amount of time needed to sufficiently heat the oil.

 

University of Wisconsin, Madison Department of Chemistry. http://www.chem.wisc.edu/areas/organic/orglab/tech/oilbath.htm (accessed April 4, 2014).

 

Gelosa, D.; Sliepcevich, A. Chemical Laboratory Techniques; Milan, Italy, 2002; pp 4-5.

 

 

Thin layer chromatography is used primarily in the identification of compounds.  Compounds move up the TLC plate based on polarity. Since the silica gel on the plate is highly polar, polar compounds adhere more strongly to the plate and move more slowly with the solvent up the plate (smaller retention factor, Rf). Conversely, nonpolar compounds have weaker interactions with the polar plate and stronger interactions with the comparatively more nonpolar solvent, moving farther up the plate (larger retention factor, Rf). Here, the reaction mixture was plated on 0.25 mm E. Merck silica gel plates (60F-254) and was visualized using an UV light. The solvent used was an acidic mixture of anisaldehyde, phosphomolybdic acid, or ceric ammonium molybdate, or basic aqueous potassium permangante (KMnO4), and heat.

 

Zubrick, J. W. The Organic Chem Lab Survival Manual: A Student’s Guide to Techniques, 9th ed.; Massachusetts, 2014; pp 223-233.

 

 

 

Liquid/liquid extraction is a technique typically performed using a separatory funnel where two liquids are insoluble in one another, one in which the product is soluble and one in which any impurities are soluble. In this reaction, the layers were water and ethyl acetate (4 portions) and the layer containing the purified (extracted) product was collected. Additionally, after the organic layers were combined, they were washed with brine (saturated salt water). Brine is typically used to break up any emulsions and extract water. Finally, the solution was dried over sodium sulfate, a drying agent.

 

Zubrick, J. W. The Organic Chem Lab Survival Manual: A Student’s Guide to Techniques, 9th ed.; Massachusetts, 2014; pp 128-135.

 

Massachusetts Institute of Technology Chemistry, http://ocw.mit.edu/courses/chemistry/5-301-chemistry-laboratory-techniques-january-iap-2012/labs/MIT5_301IAP12_Work_Handout.pdf  (accessed April 4, 2014).