Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 636-09-9, Whether you call it Diethyl Terephthalate, 1 -4-Benzenedicarboxylic Acid Diethyl Ester or Terephthalic Acid Diethyl Ester you can be assured the Diethyl Terephthalate products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.