Concentrated hydrochloric acid 12n hcl

Acetonitrile (ACN) and concentrated hydrochloric acid (12N HCl) were purchased from Fisher Scientific (Pittsburgh, PA, USA) and used as supplied. Diglyme and dinitrophenylhydrazones of formaldehyde, acetaldehyde, acetone, acrolein, crotonaldehyde, propionaldehyde, and MEK were purchased from Sigma-Aldrich (St. Louis, MO, USA) and used as supplied. 2,4-Dinitrophenylhydrazine (DNPH) was purchased from BOC Sciences (Shirley, NY, USA). DNPH was recrystallized before use to remove water.^{23 (link)} In brief, 17 g DNPH was dissolved in 350 mL acetonitrile (ACN), heating at 70°C for 1 hour, and then cooled. Once at room temperature, the crystals were collected by vacuum filtration and stored in a desiccator.

Acetonitrile (ACN) and concentrated hydrochloric acid (12N HCl) were
purchased from Fisher Scientific (Pittsburgh, PA, USA) and used as supplied.
Diglyme and dinitrophenylhydrazones of formaldehyde, acetaldehyde,
crotonaldehyde, propionaldehyde, and MEK were purchased from Sigma-Aldrich (St.
Louis, MO, USA) and used as supplied. 2,4-Dinitrophenylhydrazine (DNPH) was
purchased from BOC Sciences (Shirley, NY, USA) and recrystallized before use to
remove water, which can affect the reactivity of DNPH with carbonyls (Risner and Martin, 1994 (link)). Recrystallization
was done by dissolving 17 g DNPH in 350 mL acetonitrile, heating this solution
at 70°C for 60 min., and then cooling to room temperature. The crystals
were collected via vacuum filtration, and then stored in a desiccator.