N-Acetylsulphanilic acid

• CAS: 121-62-0
• Catalog Number: ACM121620
• Category: Main Products
• Molecular Weight: 215.22636
• Molecular Formula: C₈H₉NO₄S
• Synonyms: N-acetylsulphanilic acid;Acetyl sulphanilic acid ;4-(Acetylamino)benzenesulfonic acid;Benzenesulfonic acid, 4-(acetylamino)-;Einecs 204-487-2;N-Acetylsulfanilic acid;Acetanilide-p-sulfonic Acid
• IUPAC Name: 4-acetamidobenzenesulfonicacid
• Canonical SMILES: CC(=O)NC1=CC=C(C=C1)S(=O)(=O)O
• InChI Key: ZQPVMSLLKQTRMG-UHFFFAOYSA-N
• Density: 1.481g/cm³
• EC Number: 204-487-2
• Exact Mass: 215.02500

Case Study

Study on the Acid-Catalyzed Hydrolysis of N-Acetylsulphanilic Acid

Barnett J W, et al. Journal of the Chemical Society, 1972 (15), 2378-2381.

The hydrolysis rates of N-acetylsulphanilic acid were measured in H2SO4 at various acidities and temperatures. In H2SO4 (<75% w/w), the data fit well the criteria of Bunnett and Bunnett-Olsen for an A-2 mechanism. In more concentrated acids, the Arrhenius parameters indicate a transition to an A-1 mechanism, and the hydrolysis rate increases with increasing acidity.
· In Table 1, the pseudo-first-order rate constants of hydrolysis, kψ, of N-acetylsulphanilic acid in sulphuric acid at different temperatures are presented. The rate profiles demonstrate smooth curves with minimal variation, exhibiting a peak between 30 and 35% wlw, followed by a dip around 77% w/w H2SO4.
· Table 2 displays the Arrhenius parameters for the hydrolysis of N-acetylsulphanilic acid based on acidity levels. There is a slight rise in E and log& values within the peak region, but beyond the dip, these values escalate rapidly.
· At 70% w/w H2SO4, N-acetylsulphanilic acid is nearly entirely transformed into its conjugate acid based on the measured PKBH+ value. Therefore, above this acidity level, treating N-acetylsulphanilic acid as a potent base is warranted.
· Between 70-80% w/w H2SO4, two mechanisms occur simultaneously at comparable rates. The validity of the simplistic Arrhenius equation may be questionable in this scenario, potentially explaining the unusual values of Ea and log10A for N-acetylsulphanilic acid data in 75.7% w/w H2SO4.