Nitric acid fuming nitric acid at concentrations above 86%. Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as pigments in inks and dyes. Nitric acid is also commonly used as a strong oxidizing agent. Commercially available nitric acid is an azeotrope with water at a concentration of 68% HNO, which is the ordinary concentrated nitric acid of commerce. This
Sorbic acid Sorbic acid Sorbic acid, or 2,4-hexadienoic acid, is a natural organic compound used as a food preservative. It has the chemical formula CH(CH)COH. It is a colourless solid that is slightly soluble in water and sublimes readily. It was first isolated from the unripe berries of the "Sorbus aucuparia" (rowan tree), hence its name. The traditional route to sorbic acid involves condensation of malonic acid and trans-butenal. It can also be prepared from isomeric hexadienoic acids, which are available via a nickel-catalyzed reaction of allyl chloride, acetylene, and carbon monoxide. The route used commercially, however, is from crotonaldehyde and ketene.