Transformation Of 1,2,6-hexanetriol To 1,6-hexanediol And 1,2-pentanediol Over Ruthenium-based Catalysts By Catalytic Hydrogenolysis Process

As the renewable organic carbonaceous resource,biomass reserves are abundant in nature.Biomass-derived compounds have specific structural with a large amount of oxygen-containing groups,It is a huge challenge to make higher value-added oxygenated chemicals by the specific structural.1,2,6-hexanetriol is one of the important derivatives from 5-hydroxymethylfurfural?5-HMF?,Which mainly derived from corn cob,bagasse and other agricultural and forestry wastes and its industrial production has gradually matured.As a large agricultural production country,China can provide raw material for large-scale production of 1,2,6-hexanetriol.The development of downstream products of 1,2,6-hexanetriol has important research significance for the full utilization of 5-HMF.1,6-Hexanediol and 1,2-pentanediol are attractive in many polyol chemicals,they are widely used in the production of medicines,pesticides,polyurethanes.At the same time,it has important scientific research value for the preparation of 1,6-hexanediol and 1,2-pentanediol by using the biomass-based derivative 1,2,6-hexanetriol,In the current study,the 1,2,6-hexanetriol was employed as a model compound can better understand the behavior of selective dehydroxylation and carbon-carbon bond cleavage of polyols.1,2,6-hexanetriol has the same or similar C atom and O atom number as 1,6-hexanediol and 1,2-pentanediol,and the C/O and C/H ratios are similar.In this paper,the existing structure and composition of 1,2,6-hexanetriol are fully utilized,and the selective C-O bond and C-C bond are broken by catalytic hydrogenolysis,thereby realizing 1,6-hexanediol and 1,2-preparation.In this thesis,Ru/ZrO₂ catalytic hydrolysis of 1,2,6-hexanediol to prepare 1,6-hexanediol was studied.We make a exploration about the catalytic activity of different catalysts and the effect of different solid acids on the reaction.It was found that Ru/ZrO₂combined with phosphotungstic acid has good catalytic activity for the hydrogenolysis of 1,2,6-hexanetriol.At the same time,the conversion and selectivity of 1,6-hexanediol were also explored under differents experimental conditions.The highest selectivity to 1,6-hexanediol?49%?was obtained using the Ru/ZrO₂ which contained 5 wt%Ru and calcined at 350 degrees at 17%1,2,6-hexanediol conversion under 473 K and 2 MPa H₂,water as solvent,the main by-product is tetrahydropyran-2-methanol.Next,the stability of the reaction product was investigated in the same reaction system,and the results showed that 1,6-hexanediol was directly obtained by hydrogenolysis of 1,2,6-Hexanetriol.1,2,6-hexanetriol is converted into 1,2-pentanediol with the C-C bond cleavage catalyzed hydrogenolysis by Ru/C+Ni-ZSM-5 was also studied.The catalytic activity of different Ru-based catalysts combined with different metal ion-modified ZSM-5 were investigated.It was found that Ru/C+Ni-ZSM-5 showed higher activity than other Ru-based catalysts in the hydrogenolysis of 1,2,6-hexanetriol.The effects of reaction temperature,reaction pressure,reaction time were investigated.The results showed that which water was a solvent,4 MPa H₂,200 ? reaction time 4 h,related to 1,2,6-hexanetriol has a complete conversion and the selectivity of 1,2-Pentanediol was 88%.