KF/水滑石的合成及催化大豆油酯交换制备生物柴油

采用浸渍法制备了KF/水滑石固体碱催化剂,并将其用于催化大豆油与甲醇进行酯交换反应制备生物柴油;考察了催化剂制备条件和酯交换反应条件对生物柴油收率的影响,并对催化剂进行了XRD,TG-DTA,SEM表征。研究结果表明,KF/水滑石的最佳制备条件为:KF负载量(占水滑石的质量)80%、焙烧温度500℃、焙烧时间3 h。将此条件下制备的KF/水滑石催化剂用于大豆油与甲醇酯交换反应,最佳的反应条件为:催化剂用量(占大豆油的质量)2%,甲醇与大豆油的摩尔比12∶1,反应时间3 h,反应体系处于回流状态。在此条件下,生物柴油的收率高达90.4%。表征结果显示,KF/水滑石的催化活性与KF和水滑石在高温煅烧时相互作用形成新的晶相KMgF3和K3AlF6有关。

Preparation of Biodiesel from Soybean Oil by Transeterification over Synthesized KF/Hydrotalcite Catalyst

KF/hydrotalcite solid base catalyst was prepared by impregnation,characterized by means of XRD,TG-DTA and SEM,and then used in the transesterification of soybean oil and methanol to biodiesel.The effects of the catalyst preparation conditions and reaction conditions on the biodiesel yield were studied.The results showed that under the optimum catalyst preparation conditions of KF loading(based on the mass of hydrotalcite) 80%,calcination temperature 500 ℃ and calcination time 3 h,and the optimum transesterification conditions of KF/hydrotalcite catalyst dosage 2%(based on the mass of soybean oil),n(methanol)∶n(soybean oil) 12∶1 and reaction time 3 h in refluxing state,the yield of biodiesel could reach 90.4%.The characterization results indicated that the activity of the KF/hydrotalcite catalyst was related to the forming of the new crystalline phases of KMgF3 and K3AlF6due to the interaction between KF and hydrotalcite at high calcination temperature.