formaldehyde - Sciencemadness Dot Org

22S FORMALDEHYDE
Since strongly acidic catalysts are required, it is also possible that a rnethykJ
derivative is primarily formed by reaction of formaldehyde with acid and
that it is thi- intermediate which add? to the unsaturated linkage,
CH2o - nsoi —> HOGHa-Hso*
\ / \ /
C=C - HOCH-HSO, > C C—
HSO4 CH2OH
Hydrolysis of the above product would give a 1,3-glycol, whereas cleavage
of acid would lead to the formation of an unsaturated alcohol:
\ / \ /
C C— 4- HoO • C C— + H3S04
/ll /\ I
HSO< CH«GH O CH£OH
H
\ / \ /
C C— * C=C H- HSOr
/I I / I
SSO4 CH2OH CH2OH
Although the production of unsaturated aleohols by the action of formaldehyde
on limonene and pinene was clearly demonstrated by Kriewitz 43 in
1S99, it was not until 1917 that Prins 51,5 - made the first really comprehensive
study of the reactions of formaldehyde with ethylenic hydrocarbons. Priiis
studied reactions of formaldehyde with styrene, anethole, pinene, ef-limonene,
camphene and cedrene in the presence of sulfuric acid, using water,
glacial acetic, or formic acid as solvent. In general, the most satisfactory
results were obtained in the acid solvents. In aqueous media, the products
were generally isolated as formaJs of 1,3-glycoIs or unsaturated alcohols.
whereas acetic or formic esters were usually obtained when the corresponding
acids were employed as solvents,
By reaction of formaldehyde with styrene in glacial acetic acid containing
approximately 13 per cent by weight of concentrated sulfuric acid at 40
to 50°C, Prins obtained the diacetate of a phenyl propylene glycol. Prins
did not determine the exact structure of this glycol but proposed the
alternative formulas C6H5CHOHCH2CH2OH and CeHsCH(CHaOHu.
Fourneau and co-workers 19 have since demonstrated that Prins' glycol was
C6H5CHOHCH2CH2OH. They also.obtained cmnamyl alcohol, CeH5CH:
CH*CH2OH, as a by-product of the hydrolysis of the diacetate. Prins
claimed to have isolated a fonr-membered cyclic ether from formaldehyde-