When I’ve researched “that old book smell” in the past, the words used to describe the aroma are “grass & vanilla.”
The folks at compoundchem.com–where they offer “everyday exploration of chemical compounds”–have broken it down a bit more:
‘Old book smell’ is derived from this chemical degradation. Modern, high quality papers will undergo chemical processing to remove lignin, but breakdown of cellulose in the paper can still occur (albeit at a much slower rate) due to the presence of acids in the surroundings. These reactions, referred to generally as ‘acid hydrolysis’, produce a wide range of volatile organic compounds, many of which are likely to contribute to the smell of old books. A selected number of compounds have had their contributions pinpointed: benzaldehyde adds an almond-like scent; vanillin adds a vanilla-like scent; ethyl benzene and toluene impart sweet odours; and 2-ethyl hexanol has a ‘slightly floral’ contribution. Other aldehydes and alcohols produced by these reactions have low odour thresholds and also contribute.
Well, they might have sucked the romance out, but they’ve replaced it with a fun infographic.
Actually, they’ve provided quite a long breakdown of both the old and new book aromas on their website. And they have a button where you can download a larger copy of the infographic suitable for printing. Proper credit is included on the graphic.