2912: Aldehyde; cyclic polymer of aldehyde; paraformaldehyde

291211: Methanal (formaldehyde) 291212: Ethanal (acetaldehyde) 291213: Butanal (butyraldehyde, normal isomer) 291219: Acyclic aldehydes w/out other oxygen function, nes 291221: Benzaldehyde 291229: Cyclic aldehydes w/out other oxygen function, nes 291230: Aldehyde-alcohols 291241: Vanillin(4-hydroxy-3-methoxybenzaldehyde) 291242: Ethylvanillin(3-ethoxy-4-hydroxybenzaldehyde) 291249: Aldehyde-ethers, aldehyde-phenols & aldehydes w oth oxygen function, 291250: Cyclic polymers of aldehyde 291260: Paraformaldehyde 2912: Aldehyde; cyclic polymer of aldehyde; paraformaldehyde