Fine chemicals are pure, single chemical substances that are commercially produced with chemical reactions for highly specialized applications. Fine chemicals produced can be categorized into active pharmaceutical ingredients and their intermediates, biocides, and specialty chemicals for technical applications.
In chemical technology, a distinction is made between bulk chemicals, which are produced in massive quantities by standardized reactions, and fine chemicals, which are custom-produced in smaller quantities for special uses. There is a very large number of fine chemicals that are produced, and thus the chemistries of producing them need to be flexible, whereas the atom economy is not as critical as for bulk chemicals. Owing to the small volume and often-changing chemistry, fine chemicals production is more expensive, generates more waste and requires a higher research investment per kilogram. However, fine chemicals are produced in industrial quantities unlike research chemicals, which are produced only in the laboratory.