Study Of Carbonylation Over Mordenite Molecular Sieve

Dimethyl ether can be used not only as a clean energy source but also as a chemical raw material to produce a series of chemical products.The carbonylation reaction over H-type mordenite(H-MOR)is the core process to produce ethanol wihch has a wide range of application prospects.In this dissertation,we mainly investigate the rapid deactivation of H-MOR during the dimethyl ether carbonylation process.To improve the catalytic activity and stability,the H-MOR catalysts are modified by post-treatment method and introduction of metal ions together with soft or hard template in the synthesis process.In the post-treatment modification process,acid treatment as well as alkali treatment and hydrothermal treatment are used.Both the acid treatment and alkali treatment can effectively increase the specific surface area and the mesopore pore volume of the molecular sieve,but the suface structure of the molecular seive is destroyed at the time,resulting in the reduction of the active center.Hence,the catalytic activity and stability are not improved.But the hydrothermal treatment at 300 0C significantly improved the catalyst stability.The spent catalyst which was post-treated by hydrothermal are characterized by TPO,and it has a much higher capacity for carbon deposition compared with the unmodified MOR.We add hydroxyethyl cellulose and carbon black as hard templating agents in the synthesis process of mordenite.The mordenite synthesized by adding 15 g of A type carbon black shows better carbonylation performance.It is found that the specific surface area,mesoporous pore volume and carbon capacity of the catalyst increase by adding hard tempate.MOR-E-Cu was synthesized by adding both the E soft templating agent and Cu ions,which significantly improves the stability of the catalyst.The reaction evaluation and characterization show that the amount of DME adsorption is significantly increased by the increase of mesopores volume,and the amount of CO adsorption is enhanced by introduction of Cu.Characterization of TPO and TG show that the capacity of carbon deposition over MOR-E-Cu is significantly enhanced,which is consistent with the improvement of catalytic stability.