Thermodynamic Analysis and Experimental Study of Selective Dehydrogenation of 1,2-cyclohexanediol over Cu₂₊₁O/MgO Catalysts

• Main Authors: Haiou Wang, Qiusheng Yang, Yucong Song, Yanji Wang
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Sustainability
• Subjects: 1,2-cyclohexanediol; Cu₂₊₁O/MgO; dehydrogenation; 2-hydroxy cyclohexanone; 2-hydroxy-2-cyclohexen-1-one
• Online Access: https://www.mdpi.com/2071-1050/11/3/902

The dehydrogenation of 1,2-cyclohexanediol (CHD) helps in the effective utilization of not only fossil derivatives but also vicinal diols and polyols from sustainable biomass-derived resources. A thermodynamic analysis of CHD dehydrogenation was computed with density functional theory (DFT) calculation using Gaussian 09. The result indicates that CHD can be converted to 2-hydroxy cyclohexanone (HCO), 2-hydroxy-2-cyclohexen-1-one (HCEO) and pyrocatechol depending on the degree of dehydrogenation. HCO and HCEO are the stable products of the primary and secondary dehydrogenation. Experimentally, Cu/MgO catalysts were prepared using glucose as a reductant, and were characterized by SEM, TEM, XRD, XPS, TPR, BET and ICP. Furthermore, their catalytic performance regarding the oxygen-free dehydrogenation of CHD was investigated. The results indicate that the primary active crystalline phase of Cu/MgO was Cu₂₊₁O, and that the dehydrogenation products were mainly HCO and HCEO, in accordance with thermodynamic predictions. Upon optimizing the reaction conditions, the total selectivity of HCO and HCEO exceeded 90% and the conversion of CHD was approximately 95%.