Al2(SO4)3催化热解油转化生产酯类燃料

酸类、糖类等不稳定组分的存在是制约热解油直接用作生物燃料的主要因素。为了解决此问题,提出采用Al₂(SO₄)₃催化剂将这些不稳定成分酯化为燃料类化合物的途径。首先,分别以单模型化合物左旋葡萄糖或乙酸为原料,考察各种金属硫酸盐催化其转化制备乙酰丙酸乙酯或乙酸乙酯的能力,筛选出催化性能最好的催化剂;其次,以左旋葡萄糖和乙酸的模型混合物为原料,探究Al₂(SO₄)₃ 催化同时转化制备酯类的最佳反应条件;最后,以真实热解油为原料,验证Al₂(SO₄)₃在最佳反应条件下催化酯化的可行性。结果表明,酯化后热解油中大部分酸、糖、醛消失,同时产生大量的酯和缩醛,酯类和缩醛类占改性热解油总色谱面积的39.5%。Al₂(SO₄)₃能有效将热解油中的酸类、糖类等不稳定组分酯化为燃料类化合物,可为热解油转化制备生物燃料提供借鉴。

Production of esters fuel from pyrolysis oil using Al2(SO4)3 catalyst

In this paper, a way that using Al2[DK](SO4)3 catalyst to esterify those labile components (such as acids and sugars) in pyrolysis oil into fuel compounds was proposed considering that their presences were the main factor restricting pyrolysis oil''s direct use as biofuel. Firstly, various metal sulfates catalysts were screened for producing ethyl levulinate from model compound levoglucosan or for producing ethyl acetate from model compound acetic acid. Secondly, the optimal reaction conditions were investigated for producing esters from the model mixture of levoglucosan and acetic acid over Al2[DK](SO4)3 catalyst. Thirdly, the feasibility of producing esters from the real pyrolysis oil over Al2[DK](SO4)3 catalyst under the optimum reaction conditions was validated. The results showed the formation of significant amounts of esters and acetals accompanying the loss of labile acids, sugars and aldehydes. The esters and acetals accounted for 39.5% of the total GC-MS chromatographic area of the esterified pyrolysis oil. This indicated that Al2[DK](SO4)3 could effectively catalyse the esterification of those labile components in pyrolysis oil to fuel compounds, which could provide reference for producing biofuels from pyrolysis oil.