180 Mr Dunlop, Note on the effect of heating 
Note on the effect of heating paraformaldehyde with a trace of | 
sulphuric acid. By J. G. M. DuNntop, M.A., Gonville and Caius 
College. 
| 
[Read 24 February 1913.] | 
PRATESI (Gaz. XIv. 139) described a polymeric variety of | 
formaldehyde, soluble in alcohol and other solvents, and to which | 
he gave the name a trioxymethylene. This he prepared by | 
heating paraformaldehyde (trioxymethylene) with a trace of | | 
concentrated sulphuric acid for some hours in a sealed tube at ; 
115°C. The a trioxymethylene was described as condensing in | 
the cooler portion of the tube in long needles. 
The present author, having occasion to require a strong solution 
of formaldehyde in alcohol (in which paraformaldehyde is in- 
soluble), began to prepare « trioxymethylene in this way. . 
For convenience it was thought desirable to use a tube about | 
60 cm. long, bent in the middle into a right angle, so that the end 
containing the paraformaldehyde and sulphuric acid could be | 
heated in a tube furnace, the a trioxymethylene being condensed 
in the other limb, which was immersed in a beaker of water. 
The distillate was found to consist of a very mobile liquid, | 
which when distilled gave two fractions, one distilling at 33°C. | 
and the other at about 100°C. 
The more volatile fraction had an ethereal odour, and did not | 
react with sodium bisulphite. On investigation it was found to 
be methyl formate, and this was confirmed by comparison with a 
specimen of this ester, the boiling point and density being | 
identical. On hydrolysis with moist lead oxide it yielded lead 
formate and methyl alcohol. 
The yield of methyl formate is very variable, and depends on | 
the amount of sulphuric acid and also on the temperature. With 
about six drops of acid to ten grams of trioxymethylene, a yield of | 
about one to two grams of ester appears to be usual. In an ex- | 
periment in which about five grams of acid to ten grams of trioxy- 
methylene were taken, great charring took place, and practically 
no ester was formed. 
The reaction appears to take place by an intermolecular | 
exchange of linkages thus: 
C=6 H,C—o 
————— 
H_C_H  H CH, ie He cover 
| | 
O O 
