Xanthydrol

9-Hydroxyxanthene; xanthen-9-ol; C₁₃H₁₀O₂ = 198.2 (90-46-0)

Content, minimum 90.0%.

White or pale-yellow powder, very slightly soluble in water, soluble in ethanol (96%) and in glacial acetic acid.

It is also available as a methanolic solution containing 90 g/L to 110 g/L of xanthydrol.

Melting point, about 123°.

AssayIn a 250 mL flask dissolve 0.300 g in 3 mL of methanol or use 3.0 mL of solution. Add 50 mL of glacial acetic acid and, dropwise with shaking, 25 mL of a 20 g/L solution of urea. Allow to stand for 12 hours, collect the precipitate on a sintered-glass filter (16) (2.1.2), wash with 20 mL of ethanol (96%), dry in an oven at 100° to 105° and weigh.

1 g of precipitate is equivalent to 0.9429 g of xanthydrol.

Store protected from light. If a methanolic solution is used, store in small sealed ampoules and filter before use if necessary.