Turn on the sand bath right away after entering the lab keeping the temperature under 40 degrees. Phosphoric acid will be used however the measurement does not need to be exact. Amount of cyclohexanol used however must be exact, this can be done by taking rb flash 30 mL beaker upright then balance set it to zero. Measure about 2.0 grams of cyclohexanol using a pipet. Then use a buret in the hood to add 85% phosphoric acid (0.5 mL). Set up fractional distillation, can be done by using black plastic connector. Heat it up at a slow constant rate rather than a fast rate, the drops should be about 20-30 seconds per drop. Do it until only 10% is left. In the vial, there should be 2 phases of liquid which are water and cyclohexene. Pipet the contents of the vial into a test tube adding water (~1 mL). Mix the two liquids and then remove the lower aqueous layer and place it in a waste beaker. Add 1M sodium hydroxide (1 mL) then mix well to remove bottom layer again. Then add brine (1-2 mL) to mix and remove lower aqueous layer once again and place in the waste beaker after. Using a dry pipet, transfer organic layer, it is organic because there should not be any more water in the liquid. Add several spheres of calcium chloride and mix it well but not crushing the spheres. Repeat it until the spheres are no longer clumping together. Transfer the dried product then sign up for GC / IR analysis. Calculate the percent yield showing hand-written calculations on a separate piece of lab notebook paper. Chemical test will need to be done to distinguish alkenes from alkanes. Run the test reactions on the product that was formed and the cyclohexane. Dichloromethane is toxic so when using avoid touching. Rinse if it touched. Bromine is reddish-orange and it reacts with alkene to form a colorless dibromide. The solution will decolorize until all of the alkene has been reacted. Take cyclohexene (0.5 mL) and cyclohexane (0.5 mL) adding together, then take 3% solution of bromine in dichloromethane and add 3 to 4 drops. For potassium permanganate which is purplish color, add cyclohexene (0.3 mL) and cyclohexane (0.3 mL) together then drop about 2 or 3 drops of an aqueous solution containing 1 percent potassium permanganate and 10% sulfuric acid. Things to look out for in this lab is cyclohexene as it is very flammable. Handle phosphoric acid with care it is very corrosive to tissue. If the skin touches phosphoric acid even a little, immediately wash the contaminated area with water using soap. Clean up spills using sodium bicarbonate in the hood and rinse all the apparatus in the waste hood with a small amount of acetone. Dispose it in the organic liquid waste container after. Make sure to save copper wire, sponge, and aluminum foil for future use.
Recent comments