Synthesis of Caffeine from Tea Leaves Using Different Extraction Techniques and Its applications

Abstract

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class drug discovered by German chemist Friedrich Ferdinand Runge. The pure state of Caffeine is a bitter, white crystalline, which is mostly used in pharmaceutical industry as caffeine sodium benzoate.  Caffeine is the most widely used substance on the planet and is also one of the most researched in regards of how it affects the human body. In the present study Camellia sinensis   assameca tea leaves are collected for the extraction of caffeine and then it will be isolated directly from tea leaves. The extraction of caffeine was carried out in two stages, namely solid liquid extraction (SLE) and liquid extraction (LLE). In the SLE operation, distilled water is used. The solubility of caffeine in water varies based on temperature. The LLE process is carried by various solvents which include di-chloro methane (DCM), Chloroform, Methyl acetate and many others which have less solubility towards the aqueous phase. Based on the percentage content of the caffeine in the tae sample, end user application of caffeine and federal government regulations, the selection of the solvent was carried.

The Experimental study was carried in a batch operation using two solvents dichloride methane and chloroform. 3- levels of extraction periods 30min, 45min and 60 minutes, 3- levels of temperatures 40, 50 and 60^oC and 3-levels of mole ratios, i.e; water- tea leave weight ratio (Brew Ratio)(WTR) 10,15,20 are considered in the study. The procedure adopted for the analysis of caffeine uses the UV spectroscopy, which is calibrated in this section. Temperature is the parameter, which plays a crucial role in the extraction of caffeine as the solubility of the compound varies (increases) drastically at temperatures of 40^oC and 60^oC, the solubility of caffeine is 2.2 and 66.7 (% wt/wt) respectively. For lower WTR moles of ’15, the yield is lesser order and at temperatures beyond to 50^oC, there is drastic improvement of yield and is independent of extraction period. With higher water moles of 20, the caffeine yield is independent of extraction period for lower temperatures and is decreasing with time for higher temperatures of 60^oC. A maximum of 2.42g of caffeine can be formed for 100g of tea leaves for the case. For the DCM solvent, the better range of the parameters observed are WTR= 20 and temperature of 60^oC. In the selection of solvent for the extraction, various factors are to be accounted along with the yield, distribution coefficient other factors such as labour, health and environmental aspects.