Every chemcials have special CAS number. Each CAS number has their own identity The CAS Number of a compound is a useful way to identify a chemical over its name. For example, the compound CAS 64-17-5 refers to ethanol. Ethanol is also known as ethyl alcohol, ethyl hydrate, absolute alcohol, grain alcohol or hydroxyethane. The CAS Number is the same for all these names. PAC Polyanionic cellulose CAS number is 9004-32-4.