Odorless white powder or white glistening needles, usually melted together. Bitter taste. Solutions in water are neutral to litmus. Odorless.
ChEBI: A trimethylxanthine in which the three methyl groups are located at positions 1, 3, and 7. A purine alkaloid that occurs naturally in tea and coffee.
Caffeine crystallises from water or absolute EtOH. [Beilstein 26 III/IV 2338.]
Caffeine may be hygroscopic. Aqueous solutions (1.12 mg/mL) are stable for three weeks at 41° F if protected from light. In normal room lighting and at room temperature, solutions are stable for 3 days. Solutions of Caffeine in water, DMSO, 95% ethanol or acetone should be stable for 24 hours under normal lab conditions. REACTIVITY: Caffeine may react with strong oxidizing agents. Caffeine is also incompatible with iodine, silver salts and tannins. Caffeine is a very weak base. Caffeine is decomposed by strong solutions of caustic alkalis.
Flash point data for Caffeine are not available; however, Caffeine is probably combustible.
respiratory stimulant;adenosine receptors antagonist
NoDoz Caplets and
Chewable Tablets (Bristol-Myers Products).
Air & Water Reactions
Efflorescent in air. Water soluble.
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug and a reversible acetylcholinesterase inhibitor. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants.
In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness. Caffeine is a cardiac and respiratory stimulant; diuretic. Caffeine is toxic at sufficiently high doses.
Central nervous system stimulant. Antagonist at A 1 and A 2A adenosine receptors and inhibitor of cyclic nucleotide phosphodiesterases. Mobilises calcium from intracellular stores and inhibits benzodiazepine binding to GABA receptors.
white to light yellow crystal powder