Title:  p-Hydroxybenzaldehyde 
CAS Registry Number:  123-08-0 
Additional Names:  4-Formylphenol 
Molecular Formula:  C7H6O2 
Molecular Weight:  122.12 
Percent Composition:  C 68.85%, H 4.95%, O 26.20% 
Literature References:  Widely distributed in plants in very small amounts.  Obtained as a byproduct from the Reimer-Tiemann reaction for salicylaldehyde from phenol:  L. F. Fieser, M. Fieser, Organic Chemistry (Reinhold, New York, 3rd ed., 1956) p 681; cf. Reimer, Tiemann, Ber. 9, 824 (1876); Herzfeld, Tiemann, Ber. 10, 64 (1877). 
Properties:  Needles from water.  Slight, agreeable, aromatic odor, mp 116°.  Sublimes at atmospheric pressure without decomposition.  Reacts like a weak monobasic acid:  Ka at 25° = 2.2´10-8.  Dipole moment:  4.19.  Sparingly sol in cold water:  1.38 g/100 ml H2O at 30.5°; more sol in hot water.  Freely sol in alc, ether.  Slightly sol in benzene:  3.68 g/100 ml C6H6 at 65°. 
Melting point:  mp 116°   |