微波条件下固体酸催化剂催化酯化生物油的研究

以乙醇和乙酸的酯化作为反应模型，考察固体酸催化剂阳离子交换树脂、SO₄²-/ZrO₂和分子筛在微波加热条件下的酯化活性。结果表明，三类固体酸催化剂的活性顺序为Amberlite树脂﹥SO₄²-/ZrO₂﹥HZSM-5，催化剂活性与酸度一致；酯化反应中水的含量对催化剂的活性有不同程度的影响，水含量较高时催化剂SO₄²-/ZrO₂酯化活性明显变差，而阳离子交换树脂仍具有较高的酯化活性。采用阳离子交换树脂对生物油进行微波催化酯化提质后，原生物油中含有的大量不同种类的羧酸被有效地转化成各种酯类，酯类化合物由原油中的4种增加到13种。与传统加热条件下生物油催化提质比较，生物油微波提质具有明显优势，提质后生物油组分得到优化。

Catalytic upgrading of bio-oil over solid acid catalysts under microwave heating

Esterification of acetic acid with ethanol under microwave heating was carried out by using three types of solid acid catalysts. The results showed that the activity of these catalysts follows the order of Amberlite resin >SO₄²-/ZrO₂ > HZSM-5. These catalysts are also different in their tolerance to water present in the bio-oil. The catalytic activity of SO₄²-/ZrO₂ decreases obviously with increasing water concentration in the reaction mixture, while Amberlite resin still exhibits a high catalytic activity in the presence of water. After catalytic upgrading of crude bio-oil under microwave heating with the cation exchange resin as the catalyst, most of the organic acids are converted into various esters through esterification with ethanol. Microwave heating is more effective than conventional heating and the components of bio-oil are then better upgraded under microwave heating.