Biodiesel was prepared by esterification of cottonseed oil crude fatty acids with methanol and with sulfuric acid as catalyst.Three fractions of the biodiesel (230—260℃
230—310℃ and 260—310℃) were collected by vacuum distillation at an absolute pressure of 2000 Pa.The densities
viscosities and solidifying points of the fractions were determined.At the same time
the composition of the biodiesel was analyzed with gas chromatography and mass spectrometry (GC-MS).It was found that the solidifying points of two fractions (230—260℃ and 230—310℃) met the national standard of 0# diesel
and the fraction of 260—310℃ could be used as fuel for low-speed engines.