formaldehyde - Sciencemadness Dot Org

BE ACTIONS OF FORMALDEHYDE WITH PHENOLS 171
On oxidation, the above formal is converted to the methylene ether-ester
of 5-nitrosalicyIic acid. Homologous methylene ethers or formate are also
obtained with numerous nitrophenols, including o-nitro-p-cresol and 4nitro-2-naphthol
13 .
Apparently the nitro group, -when present in the phenol nucleus, reduces
the tendency of the primary products to condense further, with formation
of methylene-linked products. The carboxyl group, as might be expected,
appears to function in the same maimer in some cases. Baeyer 6 obtained
a monomethylol derivative of gallic acid by reacting this compound with
formaldehyde in the presence of concentrated sulfuric acid 6 .
HO
HO -CO OH •+• CH30(aq) • HO
HO HO
HO CH2OH
COOH
Results similar to those observed with nitrophenols are also obtained
with 2,4-dichIorophenol. Zieglerand co-workers 59 obtained the methylene
ether of 2,4-dicHorosaligerdn on reaction of this phenol with formaldehyde
polymer* at 0°C for three days in a medium consisting of glacial acetic
acid to which a small amount of sulfuric acid had been added. The preformed
diehlorosaligenin was found to give the same formal when treated
•with cold concentrated hydrochloric acid and formaldehyde polymer*,
demonstrating the mechanism shown below:
H
O
CI
H
O
CI
+ CH30(p) >
G\( >CHsOH CI
+ CH20(p) —->
CI
CH2OH
4- H20
Poiyhydric Phenols. Methylol derivatives of di- or polyhydroxy phenols
are not readilv isolated since they react with considerable rapidity to
* Designated as "trioxymethylene"(?).