n-Butanol or nbk or normal butanol is a primary product with a 4-carbon structure and the chemical formula C4H9OH. Its isomers include isobutanol, 2-butanol, and tert-butanol. , which have more than two carbon atoms and have significant solubility in water. n-Butanol occurs naturally as a minor product of the fermentation of sugars and other carbohydrates and is present in many foods and beverages. It is also a permitted artificial flavorant in the United States,used in butter, cream, fruit, whiskey, ice cream and ices, candy, baked goods and cordials. It is also used in a wide range of consumer products.