Pentanoic-d9 Acid is a deuterated compound of Pentanoic Acid. Pentanoic Acid has a CAS number of 109-52-4. Valeric acid, or pentanoic acid, is a straight chain alkyl carboxylic acid with the chemical formula CH3(CH2)3COOH. Like other low molecular weight carboxylic acids, it has a very unpleasant odor. It is found naturally in the perennial flowering plant valerian (Valeriana officinalis), from which it gets its name.