We know how work or study about chemistry is expensive but we haven’t the choice:
When we make for the first time a new product within include the cost of all the equipment only the purification of the crude product notably by column chromatography is very expensive followed by the characterization of the product: RMN, GC-MS, IR, UV…all this equipments whose prices are such expensive.
To show you how just a L2 experiment for learn to students how manipulate in the lab, I have chosen an experiment I have made during my second year (L2) at the university of chemistry and after the description of the experiment, I have underline all which were essential for the achievement.
Synthesis of 2-chloro-2-methylpropan
Goal: 2-chloro-2-methylpropan (t-BuCl) was prepared by a first order nucleophilic substitution between hydrochloric acid and the 2-methylpropan-2-ol:
tBu-OH + HCl –> tBuCl + H2O
1) In a 250 mL separatory funnel, place 250 mL of tert-butanol and approximately 125 mL of concentrated hydrochloric acid.
2) Insert a stopper in the separatory funnel. Firmly hold the stopper in the ground-glass joint then invert the separator funnel
3) Shake the mixture vigorously from time to time for approximately ten minutes.
4) Allow the reaction to stand. Put the separatory funnel in a metallic ring. Rapidly, the liquid should separate into two non-miscible layers and the bottom aqueous layer should be limpid.
5) Remove the lower aqueous layer which is thrown in the sink under the hood.
6) Keep the upper layer which is the crude t-BuCl in the separator funnel.
7) Successively, wash the organic layer with 20 mL of a 5% NaOH aqueous solution.
8) Then with 20 mL of water.
9) Finally recover the t-BuCl in an Erlenmeyer-flask and dry it with calcium chloride.
10) After 15 minutes, the drying agent is removed by a liquid-solid decantation.
11) The crude dried t-BuCl is purified by distillation under atmospheric pressure.
Distillation gave a product in 62% yield with a boiling point of 50° and an experimental refractive index of 1.3835.
So, now I’m going to show you the retail of all the equipment required for an experiment of a L2 students for about three hours:
§ About safety for the students
goggles, lab coat and gloves
§§ About safety in the lab
Fire alarm, fire extinguisher, shower, rince off eye
§§§ About the bench
Fumehood, ramps, monkey bars, clamp and a sink with brush.
§§§§ About equipment
Spatula, stir bar, separatory funnel, metallic ring, beaker, erlenmeyer flask, a balance
§§§§§ About solvents-reagents
t-BuOH, HCl, NaOH, CaCl2, T-BuCl, H20. Of course always acetone to clean the flasks.
§§§§§§ Purification by distillation
Heating mantle, ice bath, round bottom flask, Vigreux column, ground glass thermometer, distillation head, Liebig condenser, distillation adapter. Reflux means heating and water flow which have a cost also !
Boiling point and refractive index.
Now, it’s easy to see how our chemistry is expensive and here I only show you a little experiment for learn to student about a basic manipulation. I can’t put the price it’s too difficult but you can imagine this little manipulation is already very expensive. Consequently, what about when we are researchers from 8 am to 8 pm at the lab with litres of eluent just for a purification, quantity of silica gel ….but we need that otherwise how work?