Ni/CaO-SiO2催化剂对β-O-4木质素模型化合物氢解产物分布的影响

Effect of Ni/CaO-SiO2 Catalyst on Hydrogenolysis Product Distributions of β-O-4 Lignin Model Compounds

采用均匀共沉淀法制备Ni/CaO-SiO2固体碱催化剂,选择2-(2-甲氧基苯氧基)-1-苯基乙醇作为典型β-O-4木质素模型化合物进行催化剂性能评价。考察了不同Ni、CaO质量分数的Ni/CaO-SiO2催化剂对β-O-4氢解转化反应的催化活性,探究其对β-O-4产物分布的影响。结果表明:Ni在β-O-4催化转化反应中起主导作用,Ni质量分数的增加有利于β-O-4的催化转化;不同质量分数的Ni、CaO均会对β-O-4的转化产物分布造成一定影响,随着Ni质量分数的增加,β-O-4转化产物种类增加,而CaO的添加会影响1-苯基乙醇的生成。考察不同载体的催化剂对β-O-4催化转化产物分布的影响,并结合XPS表征发现:其产物分布变化主要由Ni与CaO的相互作用引起,与载体无关。在此基础上,提出了Ni/SiO2与Ni/CaO-SiO2催化裂解β-O-4中C—O醚键可能的反应路径。

Ni/CaO-SiO2 solid base catalyst was prepared by deposition-precipitation(DP)method.2-(2-Methoxyphenoxy)-1-phenylethanol was used as a typical β-O-4 lignin model compound for catalyst performance evaluation.Catalytic activities of Ni/CaO-SiO2 catalysts with different mass fractions of Ni and CaO were investigated.In addition,their effects on the product distributions of β-O-4 hydrolysis were also investigated.Experimental results show that Ni plays a dominant role in the catalytic conversion of β-O-4,and high Ni mass fraction is beneficial to the catalytic conversion of β-O-4.Product distribution of β-O-4 hydrolysis is also affected by the mass ratio of Ni and CaO.As mass ratio of Ni increases,more β-O-4 hydrolysis products can be found;while CaO addition can affect the formation of 1-phenylethanol.It is also found that the interaction between Ni and CaO can significantly impact on hydrolysis product distribution,but carriers have very little impact on product distribution.In addition,the possible pathways of β-O-4 conversion over Ni/SiO 2 and Ni/CaO-SiO 2 were proposed.