Caffeine

Caffeine, also known as trimethylxanthine, coffeine, theine, mateine, guaranine, methyltheobromine and 1,3,7-trimethylxanthine, is a xanthine alkaloid found naturally in such foods as coffee beans, tea, kola nuts, Yerba mate, guarana berries, and (in small amounts) cacao beans. For the plant, caffeine acts as a natural pesticide since it paralyzes and kills some of the insects that attempt to feed on the plant.

Physical properties

Pure caffeine occurs as odorless, white, fleecy masses, glistening needles or powder.

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• Boiling point: 178 °C (sublimes)
• Melting point: 238 °C
• Density: 1.2 g/cm³
• Volatility: 0.5%
• Vapor pressure: 101 kPa @ 178 °C
• pH: 6.9 (1% solution)
• Solubility in water: 2.17%
• Vapor density: 6.7 g/m³
• Molecular weight: 194.19 g/mol