To determine which compound is not an artificial sweetener, we must first understand what each compound mentioned does:
Aspartame: A low-calorie artificial sweetener used in many sugar-free products, noted for its sweet taste.
Alitame: Another low-calorie artificial sweetener, known for being sweeter than aspartame and used in various food items.
Sucralose: A zero-calorie artificial sweetener, made from sugar, often used in drinks and food products.
Sodium benzoate: This compound is primarily used as a food preservative, not a sweetener. It helps prevent the growth of bacteria and fungus.
Based on these descriptions, sodium benzoate is the compound that is not an artificial sweetener. It is a preservative, separating it from the other compounds that are used for sweetening purposes.