| Biodiesel, which is derived from animal fat and vegetable oil bytransesterification with methanol, has attracted considerable attention recently as arenewable, biodegradable, and nontoxic fuel. In this paper, the technologies ofpreparing biodiesel by the transesterification of vegetable oil with methanol, usingdifferent catalysts were studied. The main contents and results are as follows:Firstly, biodiesel was prepared by transesterification of soybean oil with methanol,using NaOH as catalyst. The effect of the methanol/oil mole ratio,catalyst dosage,reaction time and temperature on the yield were studied. The chemical composition ofobtained product was analyzed by GC. The optimum conditions for transesterificationwere:n(methanol):n(soybean oil)=6:1, reaction temperature 60℃, reaction time 2h andamount of catalyst 1.0%(based on the oil weight).Under above conditions, the yield ofbiodiesel was 98.5%. Solid base catalyst K2O/ Zr-MCM-41 has been prepared byimpregnation methods and characterized by XRD techniques.Soybean oilester-exchange reactions catalyzed by solid base catalyst were studied. The yield ofglycerol over 95.8% was attained. The new technology features simplicity, reusablecatalyst and zero pollution.Secondly, one water-stable ionic liquid 1-(3-sulfonic acid) propyl-imidazolehydrosulfate with an alkane sulfonic acid group was prepared. Preparation of biodieselfrom soybean oil catalyzed by ionic liquid was studied. Effects of ionic liquid dosage,mole ratio of methanol to soybean oil and reaction temperature and reaction time on transesterification and stability of ionic liquid were investigated. Under optimaltransesterification conditions: n(methanol): n(soybean oil)=12:1, temperature 120℃and time 8h, amount of catalyst ionic liquid 4.0％of the oil weight, mass fraction offatty acid methyl ester could reach 96.5％. The ionic liquid was stable and could bereused. Under the optimum conditions, when the catalyst was repeatedly used for 6times, the yield ofbiodiesel reached to 90％.At last, take into account the difficulty of separateness between ionic liquid andglycerol, which is the byproduct of preparing biodiesel, acetic acid was put into theblending of ionic liquid and glycerol to product glycerol triacetate. The ionic liquidwas separated and reused. The effect of material proportion, reaction temperature andreaction time were investigated. The optimum conditions were obtained as follows:n(glycerol): n(acetic acid)=1:8, reaction temperature 80～90℃, reaction time 6h.Repeated use of the ionic liquid was investigated. Under the optimum conditions,when the catalyst was repeatedly used for 6 times, the yield of glycerol triacetatereached to 90％.
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