Study On The Transesterification Process Of Biodiesel Produced From Camptotheca Acuminata Seed Oil

Camptotheca acuminata is an important species for anti-cancer in China, and is a primary material for camptothecin extraction. The oil content of its seeds is 17.8%, however, during the extraction process of camptothecin, the seeds oil was often abandoned, which made the inefficient utilization of Camptotheca acuminata resource. In the present study, in order to improve the comprehensive utilization, the process of biodiesel production from Camptotheca acuminata seeds oil was studied, which can offer theoretical basis for the further exploiture of Camptotheca acuminata resource.In this study, Camptotheca acuminata seeds were selected as raw material, the process of seeds oil extraction by supercritical carbon dioxide was studied, and the influences of different parameters on transesterification process with alkali-catalysis and acid-catalysis were discussed, respectively, the optimum conditions were obtained.The results were as follows:1. Reversed phase high performance liquid chromatography with refractive index detection (RP-HPLC-RI) method for determination of biodeisel was establishedChromatographic column HIQ SIL C18W (250 mm×4.6 mm I.D., with pre-column 30 mm×4.6 mm I.D.), mobile phase methanol, flow rate 1 mL/min, injection volume 10μL, column temperature 40℃.Under the above conditions, the main fatty acid methyl esters in biodiesel product were determined, which were methyl linolenate, methyl linoleate, methyl oleate and methyl stearate.2. Supercritical carbon dioxide extraction conditions of Camptotheca acuminata seeds oil were optimized, the optimum extraction parameters were as follows:Extraction pressure 33 MPa, extraction temperature 45℃, extraction time 60 min, under this condition, the extraction yield was near to 13%.3. The effects of three principal variables, molar ratio of methanol to oil, amount of catalyst and reaction temperature on transesterification with KOH as an alkali-catalyst with the increasing of reaction time were studied, and the optimum parameters were obtained:Reaction temperature 60℃, amount of KOH catalyst 1% of oil weight, molar ratio of methanol to oil 8:1, conversion yield was over 90% when reaction time was 60 min.4. With H₂SO₄ as an acid-catalyst, four principal variables, molar ratio of methanol to oil, amount of catalyst, reaction temperature and reaction time, which affecting the convention yield of biodiesel were investigated, and the optimum parameters were obtained:Molar ratio of methanol to oil 15:1, reaction temperature 70℃, reaction time 40 min, amount of H₂SO₄ catalyst 3% of oil weight, the conversion yield was over 95%. 5. The main quality index of the biodiesel product from Camptotheca acuminata seeds oil were detected. Viscosity, flash point, sulfur contents, carbon residue, density and acid value were all reached the standard of tight diesel fuel in China, and also reached the standard DIN V51606 in German except flash point and sulfur contents.This research offers theoretical basis for improving the comprehensive utilization of Camptotheca acuminata resource, and it gives significant reference to resolve problems of energy shortage in China. It offers scientific basis and technical support for exploiture of Camptotheca acuminata biodiesel.