Preparation Of Inorganic Mmtand Its Catalytic Properties Of Low Concentration Ethanol Dehydration To Ethylene

Ethylene is one of important fine chemicals for petrochemical industry andone country’s development level of petrochemical can be determined by theyield of ethylene. It is exigent to increase the output of ethylene for ourfast-developing country. With the shortage of natural resource, the soaring pricesof crude oil and the progress of bio-ethanol production technology. Productionof ethylene from ethanol dehydration over solid acid catalysts has sparked a lotof interests and replaced the main source of thermal cracking of oil.Different ratios of Al/Ni-PILCs were prepared by copolymerization andused as catalysts in the reforming of bioethanol (30vol%) dehydration toethylene. The structural and textural properties were determined by severaltechniques (XRD, FT-IR and BET). Structural characterizations show the BETsurface area and the interlayer spacing d(001)of Al/Ni-PILCs increased. Thesecatalysts have a very high activity and Al-PILC exhibited the highest catalyticactivity with91.2%ethylene selectivity at500℃.Al137+can not be distributed completely since the hydroxyl polymer can notbe replaced by other cations. Montmorillonite were modified by different kinds and concentrations of inorganic acid. A gradual change of the isotherm from H4to H3hysteresis loop is observed as the increasing concentration of sulfuric acid.The lamellar of montmorillonite had been delaminated and layers per stack wereproved existing with the sulfuric acid increasing to25%. Pore size distributionsshift from3.81to9.13nm and its BET surface area increased to335m2/g. Thelamellar structure and pore size distributions changed little after modified byphosphoric acid and hydrochloric acid, its BET surface area increased to132m2/g and246m2/g, respectively.Highly dispersed and highly selective catalysts were prepared by threesteps of acid treatment, ion-exchanging and impregnation method. The resultedcatalysts were initially characterized by a combination analysis of XRD, FT-IR,TG, NH3-TPD, TEM, and N2adsorption–desorption. Characterization resultsindicated that montmorillonite have “memory effect”, the sandwich structurewere delaminated on the acid treatment and was restored after theion-exchanging, resulting in the surface area to335m2/g, weak acid sites to0.178mmol/g and balance of Lewis and Bronsted acid sites. A significantimprovement on catalytic activity was observed in the dehydration of ethanol(30vol%) to ethylene on the synthesized PTMA-H2SO4-PILC catalyst, wherein93.2%conversion and99.1%selectivity of ethylene were achieved at300oC.