Final answer:
Procaine, a key component of Novocain, is an amino ester type of local anesthetic and is the correct answer as it differs structurally from amino amides like lignocaine, xylocaine, bupivacaine, and prilocaine.
Step-by-step explanation:
The local anesthetic that is not an amino amide type among the options given is procaine. Procaine is known as an amino ester local anesthetic. It is the key component of Novocain, a brand that was historically used in dental work and minor surgeries. Procaine is typically synthesized in the presence of sulfuric acid (H2SO4) as indicated in its preparation process. On the other hand, lignocaine, xylocaine, bupivacaine, and prilocaine are all considered amino amide local anesthetics, which have a different structural composition compared to amino esters like procaine.