Chemistry. — “On the Condensation of Formaldehyde with some 
Unsaturated Compounds.” By H. J. Prins. (Communicated by 
Prof. J. BOgsrxkeEn). 
(Communicated in the meeting of May 3, 1919). 
Some time ago’) the author discussed the mutual condensation of 
unsaturated compounds, examining the condensation of formaldehyde 
with styrol, anethol, isosafrol, pinene, d. limonene, camphene and 
cedrene. The condensation was effected either by warming the compo- 
‘nents in acetic acid solution, or by sulphuric acid in an aqueous or 
acetic acid solution. For the aqueous solutions we availed ourselves 
of the 40°/, solution as supplied by the trade, the acetic acid solution 
was obtained by warming trioxymethylene in acetic acid with or 
without the presence of sulphuric acid. 
The aqueous and acetic acid solutions of sulphuric acid and formalde- 
hyde behave differently as regards certain compounds, styrol, cam- 
phene and cedrene react but extremely slowly or not at all with 
the aqueous solution whereas anethol and isasofrol do react. 
Contrary to isosafrol safrol does not affect an aqueous solution. 
It many be assumed, that the reaction begins with an addition of 
the CO group to the C=C group, so that primarily a four-ring 
is formed. 
REE. CCHR HCOSR.H.C=C. HR 
on, 
The four-ring can now: 
1. absorb water and form a 1.3 glycol: R.H.C—CHOH.R 
| 
H,COH 
2. absorb formaldehyde and form a methylene ether: 
R.HC—CH.R 
IN 
Ee: 10 
oe 
O—CH 
1) Chem. Weekbl. 10, 1003. (1913). 
ibid. 14, 982. (1917). 
4* 
