chemsample-esterfication-methods

__**Esterification ~ (Peach - Benyl Ethanoate / Benzylacetate)** Conducted by: Student A + B__

First step is to clean your vessel, then add 4mL of acetic acid, 2.4mL of benzyl alcohol, and 10 drops of sulfuric acid(ignor 2 grams of silica beads). Place the vessel into the Mars microwave and allow mixture to heat to 120 degrees Celsius. Now let vessel cool for 20 minutes.

The girl in the picture is wafting to smell her ester, which is the appropriate way to do it. You don't want to stick your nose into the vessel! The picture to the right is what the sample looked like before it went into the microwave.

Dissolve any solids with water, if any. After this is complete you must add Sodium bicarbonate to your product. Now add 5mL Diethyl Ether to the separatory funnel. This gives you an organic and aquaous layer which will be seperated from one another exactly like the girl in the picture below is doing. As you add them together make sure to release the gases by twisting the knob! (look at picture below to find out where the knob is).
 * Note:** using lubricant on the cap will prevent leakage, although use a small amount because you could loose some of your organic layer.

Picture of the seperatory funnel and how it's used for the seperation of the organic layer.

Now you will remove the aqueous layer and add 5mL of Sodium Bicarbonate. Once again relase the gases and remove the aquaous layer. Now, add 5mL of Sodium Chloride to the seperated, organic layers. Place this sample into a weighed round bottom flask and put through the rotary evaporator to strip the product of the solvents and water.

Rotary evaporator pot (can touch to make sure its reacting). Weigh the final product and subtract them from one another to obtain your yield. Also you must run an IR and NMR test to see the functional groups present ... and the structure.

__**Esterification ~ (Orange - Octyl ethanoate / octyl acetate)** Conducted by: Student B__

1) Sample preparation - 4.0 mL acetic acid, 3.6 mL 1-octanol, and 10 drops conc. sulfuric acid, prepared in a microwave reaction vessel (tube). A magnetic stir bar was then added.

2) The sample was then placed into the microwave reaction vessel which ran as follows: heated to 120 C over 3 minutes, held constant for 5 minutes, and ramped down for 20 minutes.

3) The vessel was then removed from the microwave, and cooled for another 10 minutes, or so.

4) A prepared separatory flask (filled with 10 mL, 10 %, sodium bicarbonate) was used to neutralize the excess acetic acid in the compound.

5) Diethyl ether (5 mL) was added to the solution, and swirled / vented. The solution was then separated (organic, from acetic). This process was repeated twice more, for a total of 3 consecutive separations.

6) The combined organic layers were then returned to the separatory flask and washed with 5 mL of NaCl solution. The layers were again separated, and the solution was then ready to be run in our rotary evaporator unit.

7) Solution was run in rotary evaporator unit for approx. 10-15 minutes (done in order to remove any excess / or, remaining diethyl ether).

8) The compound was then weighed on a digital scale, and calculated for yield.

9) Note - that refractive index (RI) was not measured. Though, this was the next logical step. If time permits, I will go back and run it through the refractometer.

10) The product was then run through the IR protocol to obtain an IR spectra. See link - IR Protocol. 11) The product was also run through the NMR protocol to obtain an NMR spectra. See link - NMR Protocol.

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