Selective C–C Bond Cleavage of Methylene-Linked Lignin Models and Kraft Lignin
Selective C–C Bond Cleavage of Methylene-Linked Lignin Models and Kraft Lignin
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DOI：
10.1021/acscatal.8b00200
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发表时间：
2018-06
期刊：
影响因子：
12.9
通讯作者：
Li Shuai;Jacob W. Sitison;Sunitha Sadula;Junhuan Ding;M. Thies;B. Saha
中科院分区：
文献类型：
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作者：
Li Shuai;Jacob W. Sitison;Sunitha Sadula;Junhuan Ding;M. Thies;B. Saha
生物炼制和造纸木质素，在此称为工业木质素，含有缩合的C-C单元间键。这些具有较高键解离能的稳固C-C键在氢解条件下难以破坏，氢解条件通常用于裂解生物质中天然木质素的C-O键或模型C-O连接化合物。因此，选择性单元间C-C裂解以释放用于高价值应用的芳族单体是一个挑战。我们报道了一种有效的催化体系，在温和的条件下选择性地裂解这样的C-C键。代表性的亚甲基连接的C-C模型二聚体使用商业CoS 2催化剂在合理的低温（250 °C）下在1.5小时内实现88%的主要两种芳族单体的产率。芳族单体在反应延长的时间后转化为非芳族产物。二聚体的单元间C-C键在芳环脱羟基时对裂解不起反应，而甲氧基对裂解几乎没有影响。β-1和5- 5C-...
Biorefinery and paper pulping lignins, referred hereto as technical lignins, contain condensed C–C interunit linkages. These robust C–C linkages with higher bond dissociation energies are difficult to disrupt under hydrogenolysis conditions, which are generally used for cleaving C–O bonds of native lignin in biomass or model C–O linked compounds. Thus, selective interunit C–C cleavage to release aromatic monomers for high-value applications is a challenge. We report an effective catalytic system to cleave such C–C bonds selectively under mild conditions. A representative methylene-linked C–C model dimer achieves 88% yield of mainly two aromatic monomers within 1.5 h at a reasonably low temperature (250 °C) using a commercial CoS2 catalyst. Aromatic monomers convert to nonaromatic products upon the reaction for a prolonged time. The interunit C–C bond of the dimer become unreactive to cleavage upon dehydroxylation of aromatic rings, while the methoxyl group has little effect on the cleavage. β-1 and 5-5 C–...