The Catalytic Process Optimization Of H? Molecular Sieve In The Preparation Of 2-ethylanthraquinone

In this thesis,the synthesis of 2-ethylanthraquinone by one-step Friedel-Crafts acylation reaction from phthalic anhydride and ethylbenzene was carried out over different zeolite catalysts.Among all the investigated acidic zeolites,H?zeolite showed the best catalytic performance.Under the optimal reaction conditions?catalyst 11 wt%of the reactants,n?ethylbenzene?:n?phthalic anhydride?=5:1,reaction temperature200?,reaction time 3 h?,the conversion of phthalic anhydride was achieved 35.0%with 93.5%selectivity of 2-ethylanthraquinone when H?zeolite was employed as a catalyst.The effect of SiO₂/Al₂O₃ ratio of H?zeolites on the catalytic performance was investigated.Na?zeolites with different SiO₂/Al₂O₃ ratios were modified by NaOH solution.The structures and acidic properties of the modified zeolites were characterized by XRD,SEM,FT-IR,N₂ physical adsorption and desorption,²⁹Si MAS NMR,NH₃-TPD and Py-IR.The results showed that alkaline treatment not only improved acid sites density,but also generated more secondary mesoporous,which helped improve the diffusion ability of transition state and products as well as a higher catalytic performance.The conversion of phthalic anhydride was arrived at 37.8%with95.2%selectivity of 2-ethylanthraquinone under the optimal reaction conditions in the presence of alkali-treated H?.In the reusing experiments,the alkali-treated zeolite showed higher stability than that of parent zeolite.The conversion of phthalic anhydride and the selectivity of 2-ethylanthraquinone was slightly decreased when the third regenerated zeolite by calcination was used as a catalyst.H?zeolites modified by citric acid,tartaric acid and oxalic acid were studied and the effects of acid type,concentration of acid,treatment temperature,treatment time were optimized.Under the optimal modified conditons,the reaction conditions over citric acid-treated H?zeolite were also optimized.The experiment results showed that citric acid could remove extra-framework aluminum species and compensate the framework aluminum species,adjust the distribution of Br?nsted acid sites and Lewis acid sites,which resulted in a higher catalytic performance.The conversion of phthalic anhydride was arrived at 42.4%with 93.3%selectivity of 2-ethylanthraquinone under the optimal reaction conditions when the citric acid-treated H?zeolite was employed as a catalyst.In the reusing experiments,the citric acid-treated zeolite showed higher stability and ability of coke-resistance than that of parent zeolite.The conversion of phthalic anhydride and the selectivity of 2-ethylanthraquinone was slightly decreased when the fourth regenerated zeolite by calcination was used as a catalyst.