A NOVEL SPECTROPHOTOMETRIC METHOD FOR DETERMINING THE ACID NUMBER OF TALL OIL

A spectrophotometric procedure for the determination of the acid numbe r of tall oil has been developed. The procedure involves dissolution o f a known weight of tall oil sample in acetone followed by spectrophot ometric determination of total free fatty and resin acids in the solut ion after prior complexation of the acids with cupric ions. The total free fatty and resin acids values of tall oils, as determined by the s pectrophotometric procedure, correlate well with the acid numbers of t he tall oil samples. This correlation affords an alternative rapid met hod for determining the acid number of tall oil.