Koffein er pænt vandopløsligt i kogende vand, så jeg vil råde dig til at droppe at lave nogle salte af det. (Du har vel hørt om kaffe ???)
Videre vil jeg foreslå at filtrere opløsningen og putte i køleskabet, med den enorme forskel på opløseligheden i kogende og koldt vand, er det helt sikkert muligt at krystallisere det direkte...
The Merck Index skrev:
Properties: Hexagonal prisms by sublimation, mp 238°. Odorless with bitter taste. Sublimes 178°. Fast sublimation is obtained at 160-165° under 1 mm press. at 5 mm distance. d418 1.23. pH of 1% soln 6.9. Absorption spectrum: Hartley, J. Chem. Soc. 87, 1802 (1905). One gram dissolves in 46 ml water, 5.5 ml water at 80°, 1.5 ml boiling water, 66 ml alcohol, 22 ml alcohol at 60°, 50 ml acetone, 5.5 ml chloroform, 530 ml ether, 100 ml benzene, 22 ml boiling benzene. Freely sol in pyrrole; in tetrahydrofuran contg about 4% water; also sol in ethyl acetate; slightly in petr ether. Soly in water is increased by alkali benzoates, cinnamates, citrates or salicylates. LD50 orally in mice, hamsters, rats, rabbits (mg/kg): 127, 230, 355, 246 (males); 137, 249, 247, 224 (females) (Palm).
