formaldehyde - Sciencemadness Dot Org

134
FORMALDEHYDE
evolved and carbonization takes place; with more dilute solutions, formaldehyde
polymer is formed 113 .
Nitric Acid. At ordinary temperatures, nitric acid reacts violently
•with formaldehyde, oxidising it to carbon dioxide and water, with formation
of nitric oxide and a small amount of nitrogen- A mixture of pure nitric
acid and formaldehyde may not react at once, but bursts into almost explosive
action on being stimulated 114 .
Travagli and Torboli 108 claim that formaldehyde solution can be nitrated
with mixed acids at 5°C to give the dinitrate of methylene glycol:
CH2(OH)£ 4- 2HXOi -» CH2(ONO£)£ -f HaO
If the temperature is allowed to reach 10°C, there is danger of violent
decomposition. Methylene dinitrate separate? from the nitration mixture
as an upper layer and is fairly stable when purified by washing with water.
IT- is a liquid insoluble in water, but readily soluble in organic solvents.
It is claimed to have value as an explosive,
Xitrous Acid. Nitrous acid oxidises formaldehyde to carbon dioxide
and water, with liberation of nitrogen. This reaction is the basis for a
method of nitrite analysis 113 :
4HN03 + 3CHaO(aq) -+ 3C02 + SH20 + SN3
Hydfohalogen Acids. The primary reaction product of formaldehyde
and hydrochloric acid is probabh T chloromethanol:
CH2G(aq) + HC1 — CICHsOH
This product has never been isolated and its existence is purely hypothetical.
When an excess of hydrogen chloride is reacted with formaldehyde
solution, dichloromethyl ether is obtained 73 . The probable
mechanism of this reaction is:
CH20{aq) + HCl -> ClOHsOH
2C1CH20H -* C1CH30CH,C1 + H30
This product is obtained in an 85 per cent yield when hydrogen chloride is
passed into a solution of paraformaldehyde hi cold concentrated sulfuric
acid, the product separating as a clear, colorless upper layer 100 . When the
reaction mixture is warmed, decomposition reactions take place and little
or no diehloroether is produced. According to Schneider 100 , traces of
methylene chloride may be present in the products obtained under these
circumstances.
DicHoromethyl ether is a colorless liquid boiling at approximately 100°C.
It hydrolyzes on exposure to water or moist air, liberating hydrogen chloride
and formaldehyde. It is not miscible with water, but is completely