Sublimation caffeine from coffee

The separation of caffeine from coffee by entrainer sublimation... 

Your instructor has been given a new and simple entrainer sublimator that it is supposed to work quite well. You are to test it for him by separating caffeine from coffee. First you are to determine if anything can be sublimed from coffee. If there is any sublimate, you will try to identify it. 

Cuffeine is extracted from tea dust and during coffee roasting, caffeine sublimes. Caffeine has above all a centrally stimulant (analeptic) effect on the cerebrum, produces tachycardia and has a diuretic effect. 

Tea yields better-quality caffeine than that obtained from coffee. Caffeine from tea is relatively colorless, whereas the caffeine extracted from coffee is highly colored. About 25 mg of caffeine is isolated in either case. Sublimation removes much of the color from the tea and coffee samples. 

C8H10N4O2. An alkaloid occurring in tea, coffee and guarana, from which it may be prepared by extraction, It is also manufactured by the methylation of theobromine and by the condensation of cyanoacetic acid with urea. Crystallizes with H2O or anhydrous from organic solvents. M.p. (anhydrous) 235"C, sublimes at 176 C. Odourless, and with a very bitter taste. Caffeine acts as a stimulant and diuretic, and is a constituent of cola drinks, tea and coffee. 

Caffeine, mp 263°C, sublimes on heating and is more soluble than dimethylxanthines. Caffeine has a stimulating effect on the central nervous system. It is extracted from green coffee beans with liquid CO2 [151]. Caffeine is synthesized by methylation of xanthine, theophylline or theobromine with methyl iodide or dimethyl sulphate [149]. 

The caffeine obtained from tea or coffee can be purified by sublimation using the procedure described in Experiment 13A. At your instructor s option, you may combine your sample with another student s sample for sublimation. After sublimation, determine the weight of caffeine recovered and calculate the weight percentage recovery of the caffeine. Compare this value to the amount of crude sample obtained. At the instructor s option, determine the melting point of the purified caffeine. The melting point of pure caffeine is 236°C however, the observed melting point will be lower. Submit the sample to the instructor in a labeled vial unless it is to be used for infrared spectroscopy (recommended) or mass spectroscopy (also recommended). 

Attach your infrared spectra to your report and label the major peaks. If you determined the mass spectrum, try to identify the important fragment ion peaks (Technique 28). Include the melting point, if it was required. Report the weight percentage of the caffeine recovered from the tea or coffee sample before and after sublimation. 

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