Hydroxybenzaldehydes
Hydroxybenzaldehydes | ||||||
Surname | 2-hydroxybenzaldehyde | 3-hydroxybenzaldehyde | 4-hydroxybenzaldehyde | |||
other names |
o -hydroxybenzaldehyde, 2-formylphenol, salicylaldehyde |
m -hydroxybenzaldehyde, 3-formylphenol |
p -hydroxybenzaldehyde, 4-formylphenol |
|||
Structural formula | ||||||
CAS number | 90-02-8 | 100-83-4 | 123-08-0 | |||
PubChem | 6998 | 101 | 126 | |||
Molecular formula | C 7 H 6 O 2 | |||||
Molar mass | 122.13 g mol −1 | |||||
Physical state | liquid | firmly | ||||
Melting point | −7 ° C | 104 ° C | 116-117 ° C | |||
boiling point | 197 ° C | 240 ° C | ||||
pK s value | 6.79 | 8.00 | 7.66 | |||
GHS labeling |
|
|
|
|||
H and P phrases | 302-315-319-335 | 315-319-335 | 315-319-335 | |||
no EUH phrases | no EUH phrases | no EUH phrases | ||||
261-302 + 352 305 + 351 + 338-321-405-501 |
261-305 + 351 + 338 | 261-305 + 351 + 338 |
In chemistry, hydroxybenzaldehydes form a group of substances that are derived from both benzaldehyde and phenol . The structure consists of a benzene ring with attached aldehyde (-CHO) and hydroxyl group (-OH) as substituents . Their different arrangements ( ortho , meta or para ) result in three constitutional isomers with the empirical formula C 7 H 6 O 2 . They are mainly to be regarded as derivatives of benzaldehyde. 2-Hydroxybenzaldehyde is known by its common name, salicylaldehyde .
properties
The hydroxybenzaldehydes have (9.99) is significantly lower compared to the phenolic pK s values ; the electron-withdrawing aldehyde group ( −M effect ) increases the acidity; the phenolic OH bond is increasingly polarized.
Individual evidence
- ↑ a b c Entry on salicylaldehyde in the GESTIS substance database of the IFA , accessed on August 19, 2012(JavaScript required) .
- ↑ a b c d e f CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
- ↑ Data sheet 3-Hydroxybenzaldehyde from Sigma-Aldrich , accessed on May 3, 2011 ( PDF ).
- ↑ Data sheet 4-Hydroxybenzaldehyde from Sigma-Aldrich , accessed on May 3, 2011 ( PDF ).