超临界甲醇中复合金属氧化物催化木质素的解聚  

Depolymerization of Lignin Catalyzed by Complex Metal Oxide in Supercritical Methanol

作　　者：叶结旺 蒋剑春[1] 金贞福[2] 章卫钢[2] 张晓春[2] YE Jiewang1,2, JIANG Jianchun1, JIN Zhenfu2, ZHANG Weigang2, ZHANG Xiaochun 2(1.Institute of Chemical Indusnry of Forest Products, Chinese Academy of Foresnry （CAF） , Nanjing 210042, 2.Cooperative Innovation Center of Bamboo Resources and Efficient Utilization in Zhejiang Province, Zhejiang Agriculture ＆ Foresnry University, Lin＇an 311300, China)

机构地区：[1]中国林业科学研究院林产化学工业研究所,江苏南京210042 [2]浙江农林大学浙江省竹资源与高效利用协同创新中心,浙江临安311300

出　　处：《林产化学与工业》2018年第4期52-60,共9页Chemistry and Industry of Forest Products

基　　金：国家自然科学基金资助项目(31530010);中央级公益性科研院所基本科研业务费专项资金(CAFYBB2014ZD003);科技部中日双边合作项目(2016YFE0125800)

摘　　要：以类水滑石为前驱体制备了Cu/Ni掺杂的层状双金属氧化物(Cu/Ni-LDO)催化剂,探讨了超临界甲醇中,反应条件对Cu/Ni-LDO催化木质素解聚产物的影响。结果表明:在n(Cu)∶n(Ni)=1∶1,反应时间8 h,温度280℃,30%Cu0.5Ni0.5Mg3Al-LDO为催化剂的条件下,单体得率高达67.5%,而四氢呋喃(THF)不溶残渣和残炭的得率最少。采用GC-MS对木质素解聚的液体产物进行了定性和定量分析,结果显示环状化合物的得率为64.43%,非环状结构的产物只占10.65%,Cu/Ni-LDO催化剂能够有效断裂木质素结构单元间的连接键,但对芳环结构的断裂能力有限。Cu/Ni-LDO催化剂能够有效的抑制木质素解聚产物的成炭反应,并能显著地提高单体的收率。高温可以有效促进木质素解聚过程中的氢解和加氢反应,获得了更高的单体收率。温度对超临界甲醇木质素解聚反应有显著的影响,反应温度高于240℃时,单体的收率显著增加,THF不溶残渣和炭的得率则明显减少。催化剂循环使用3次后,木质素的降解率依然保持90%以上。通过XRD、ICP及N2吸/脱附实验分析表明Mg的浸出是催化剂失活的主要原因。Cu/Ni-LDO催化剂在超临界甲醇介质中能够有效地促进木质素解聚为小分子的单体化合物。Cu-Ni doped layered double oxide （LDO） catalysts were prepared from hydrotalcite-like precursors. The effects of reaction conditions on the catalytic lignin depolymerization productswere investigated in supercritical methanol. The results showed that in the condition of n （Cu） ∶ n （Ni）=1 ∶1, at 280 ℃ for 8 h,Cu 0.5 Ni 0.5 Mg 3Al-LDO used as catalyst with 30% dosage, the monomer yield from lignin depolymerization was up to 67.5%, while the yields of tetrahydrofuran（THF） insoluble residue and charwere least. The liquid phase product were qualitatively and quantitatively analyzed by GC-MS, and it was observed that the yield of the cyclic compound was 64.43%, and the acyclic product was only 10.65%, indicating Cu/Ni-LDO catalyst can effectively break the bonds between the lignin structural units, while with a lowactivity to break the aromatic ring structure.Charforming reactions in lignin depolymerization were effectively suppressed by Cu/Ni co-doped LDO catalyst, and the monomer yield was significantly improved. Hydrogenolysis and hydrogenation reaction in lignin depolymerization were promoted obviously at higher temperature,leading to a higher monomer yield. The supercritical temperature of methanol showed a significant effect on the depolymerization of lignin： When the reaction temperature was higher than 240 ℃, the yield of monomer increased significantly and the yields of insoluble residue and char decreasedon the other hand. The degradation rate of lignin remained above 90% after the catalyst was recycled for three times. XRD, ICP and N 2 adsorption and desorption experiments showed that leaching of Mg was the main cause for catalyst deactivation. Cu/Ni-LDO catalyst can effectively promote the depolymerization of lignin into small molecule monomer compounds in supercritical methanol medium.

关 键 词：木质素 解聚 层状双金属氧化物 超临界甲醇 加氢 

分 类 号：TQ35[化学工程] TK6[动力工程及工程热物理—生物能]