DataSheet1_Tungsten Promoted Ni/Al2O3 as a Noble-Metal-Free Catalyst for the Conversion of 5-Hydroxymethylfurfural to 1-Hydroxy-2,5-Hexanedione.PDF

The conversion of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) represented a typical route for high-value utilization of biomass. However, this reaction was often catalyzed by the noble metal catalyst. In this manuscript, W promoted Ni/Al2O3 was prepared as a noble-metal-free catalyst for this transformation. The catalysts were characterized by XRD, XPS, NH3-TPD, TEM, and EDS-mapping to study the influence of the introduction of W. There was an interaction between Ni and W, and strong acid sites were introduced by the addition of W. The W promoted Ni/Al2O3 showed good selectivity to HHD when used as a catalyst for the hydrogenation of HMF in water. The influences of the content of W, temperature, H2 pressure, reaction time, and acetic acid (AcOH) were studied. NiWOx/Al2O3-0.5 (mole ratio of W:Ni = 0.5) was found to be the most suitable catalyst. The high selectivity to HHD was ascribed to the acid sites introduced by W. This was proved by the fact that the selectivity to HHD was increased a lot when AcOH was added just using Ni/Al2O3 as catalysts. 59% yield of HHD was achieved on NiWOx/Al2O3-0.5 at 393 K, 4 MPa H2 reacting for 6 h, which was comparable to the noble metal catalyst, showing the potential application in the production of HHD from HMF.

5-羟甲基糠醛（5-hydroxymethylfurfural，HMF）转化为1-羟基-2,5-己二酮（1-hydroxy-2,5-hexanedione，HHD），是生物质高值化利用的典型路径之一。然而该反应通常需贵金属催化剂催化。本文制备了钨（W）改性的Ni/Al₂O₃催化剂，作为该转化反应的非贵金属催化剂。采用X射线衍射（X-ray Diffraction，XRD）、X射线光电子能谱（X-ray Photoelectron Spectroscopy，XPS）、氨气程序升温脱附（Ammonia Temperature-Programmed Desorption，NH₃-TPD）、透射电子显微镜（Transmission Electron Microscopy，TEM）以及能谱面扫描（Energy Dispersive Spectroscopy-mapping，EDS-mapping）对所制备的催化剂进行表征，以探究钨的引入对催化剂性能的影响。研究发现，镍与钨之间存在相互作用，且钨的添加可引入强酸位点。当该钨改性Ni/Al₂O₃催化剂用于水相体系中HMF的加氢反应时，对HHD展现出良好的选择性。本文考察了钨负载量、反应温度、氢气压力、反应时间以及乙酸（AcOH）对反应的影响。结果表明，当钨与镍的摩尔比为0.5时制备的NiWOₓ/Al₂O₃-0.5为最适宜的催化剂。该催化剂对HHD的高选择性源于钨引入的酸性位点，这一点可通过如下实验验证：仅以Ni/Al₂O₃作为催化剂时，添加乙酸可大幅提升HHD的选择性。在393 K、4 MPa氢气氛围下反应6 h，NiWOₓ/Al₂O₃-0.5可实现59%的HHD收率，其性能可与贵金属催化剂相媲美，展现出由HMF制备HHD的潜在应用前景。