دانلود رایگان مقاله تولید ایزوسورباید از سوربیتول بر متخلخل کاتالیزور زیرکونیوم فسفات

ABSTRACT

A porous zirconium phosphate catalyst prepared by hydrothermal method was studied for the dehydration of sorbitol to isosorbide under water-free conditions. Various characterization techniques such as XRD, Raman, SEM, NH3-TPD and Pyridine adsorption etc were conducted to determine the textural and acidic properties ofthe catalyst so as to build the relationship between catalytic performance and catalyst structure. In screening tests with other solid acids, the as-prepared ZrP sample exhibited the promising catalytic behavior for isosorbide production probably assigned to its high surface area, porous structure and the adequate Brönsted acid sites. Full sorbitol conversion with as high as 73% isosorbide selectivity could be obtained at mild conditions (210 ◦C, 2 h). Noticeably, the ZrP catalyst could be repeatedly used without any obvious deactivation. Generally, the ZrP catalyst studied in this work possessed a great potentiality as an efficient heterogeneous solid acid catalyst for isosorbide production to diminish the application of homogeneous mineral acid.

4. Conclusions

This work mainly investigated the catalytic dehydration of sorbitol to isosorbide over a porous ZrP catalyst under water free conditions. It was proposed that the isosorbide yield greatly affected by natures of acid sites and porous structure of the catalyst. A great number of Brönsted acid sites on the catalyst surface was more favorable for isosorbide formation compared to Lewis ones. Meanwhile,the porous structure ofthe catalyst promoted the accessibility of reactant molecules to acid sites. Therefore, a maximum yield of isosorbide as high as 73% could be achieved under an optimum condition of 210 ◦C and 2 h. Otherwise, ZrP was an recyclable catalyst without clear deactivation during five consecutive tests. The positive result in this work may shed light on the development of efficient catalysts for biomass conversion achieving the goal of synthesis of high-valued chemicals from renewable biomass and/or biomass-derived feedstocks.