稀土复合固体酸催化合成棕榈酸生物柴油的研究

用溶胶凝胶法制备稀土复合固体酸催化剂SO₄^2-/TiO₂/Ce⁴⁺,将其用于棕榈酸与甲醇的加压酯化反应.考察了不同制备条件对催化剂性能的影响,并对其结构进行表征.结果表明,在Ce⁴⁺浓度0.05 mol/L、H₂SO₄浓度1.38 mol/L、煅烧温度450 ℃和煅烧时间3 h的制备条件下,催化剂活性最高.棕榈酸与甲醇的加压酯化反应最佳工艺条件为:醇酸物质的量之比10:1、反应温度110 ℃、反应时间30 min、催化剂用量3%,此时转化率可达到96.33%.催化剂在重复使用4次后,转化率仍在50%以上.

Biodiesel Production from Palmitic Acid Esterificatin with Rare Earth Composite Solid Acid as Catalysts

Solid acid catalyst modified with rare earth,SO₄^2-/TiO₂/Ce⁴⁺, was prepared by sol-gel method and used for the esterification of palmitic acid and methanol.The effects of different preparation conditions on the catalyst activity were investigated,and its structure was characterized.The results indicated that the highest catalyst activity was exhibited when Ce⁴⁺ concentration 0.05 mol/L,H₂SO₄ concentration 1.38 mol/L,calcination temperature 450 ℃ and calcination time 3 h.It was found that the optimum condition were molar ratio of methanol to palmic acid 10:1,reaction temperature 110 ℃,reaction time 30 min and catalyst amount 3%,respectively.The conversion of palmitic acid was 96.33% under these conditions.The conversion rate was still above 50% when the catalysts were reused for four times.