| Alkylated gasoline is clean and pollution-free,and is an excellent blending component for commercial gasoline.However,the existing catalysts used in the process of preparing alkylated gasoline are traditional strong acids such as concentrated sulfuric acid or hydrofluoric acid as catalysts,which,while producing a good effect,also bring huge pollution to the environment.Aiming at the shortcomings of the existing catalysts,this paper uses polyethylene glycol,polypropylene glycol,and polyetheramine containing longer polyether chains as precursors,and synthesized polyethylene glycol acidic ionic liquids,polypropylene glycol acidic ionic liquids,and Polyetheramine-type acidic ionic liquids were then applied to isobutane/isobutene alkylation reactions,respectively,to develop a new synthetic route for environmentally-friendly catalytic preparation of alkylated gasoline.It can be divided into the following three catalytic systems:Polyethylene glycol type acidic ionic liquid catalyst system:Polyethylene glycol with different polymerization degrees is used as the precursor,and it is first chlorinated by the SOC12 chlorination method,and then mixed with imidazole derivatives such as methylimidazole and butylimidazole,and quaternization reaction of amine derivatives such as triethylamine,and finally anionic exchange with trifluoromethanesulfonic acid to obtain polyethylene glycol acidic ionic liquids.Infrared,nuclear magnetic and other analytical methods were used to characterize the prepared ionic liquid.A series of synthesized polyether acidic ionic liquids were combined with CF3SO3H to form an acid-catalyzed system for catalyzing the alkylation of isobutane/isobutene.GC-MS and GC were used for qualitative and quantitative analysis of the reaction products.Through analysis and detection of the reaction products,it was finally determined that[Mim-PEG 1000-Mim][TfO]2/CF3SO3H was the optimal catalytic system.The reaction conditions were optimized,and the best reaction conditions were finally obtained:VTfOH:VIL=1:5,T=35?,t=20 min,RS=700 rads/min.The single reaction conversion rate was 93.17%,and the selectivity was as high as 96.44%.After the reaction,the product and the ionic liquid can be naturally separated.After the reaction,the[Mim-PEG 1000-Mim][TfO]2/CF3SO3H catalytic system is reused several times to explore its recycling effect.In the end,it was found that after 5 cycles,the catalyst was basically deactivated.Among them,the first three catalysis can still maintain a high catalytic activity,and after three times,the activity decreased rapidly.Through observation,it is found that the color of ionic liquids is constantly deepening during the cyclic catalysis process.This may be because the generated "red oil",that is,the acid-soluble oil is largely dissolved in the catalytic system,which has caused the catalytic capacity of the catalytic system to decrease continuously.Basically loses activity after cycling.Polypropylene glycol-type acidic ionic liquid catalyst system:Based on the tunable denaturation of ionic liquids,we choose polypropylene with low viscosity as the precursor,and also use the SOC12 chlorination method to chlorinate the hydroxyl groups at both ends,and Polyimide glycol-type ionic liquids are prepared by reacting imidazole and amine derivatives of several alkyl chains,and then compounded with trifluoromethanesulfonic acid to form a composite acid catalytic system and used for the alkylation reaction of isobutane/isobutylene.To investigate the effect of longer alkyl chains on the effect of catalytic alkylation.The structure and performance of the catalyst were characterized by means of infrared,nuclear magnetic.The reaction products were analyzed qualitatively and quantitatively by GC-MS and GC.Through analysis and detection of the reaction products,[Bim-PPG 2000-Bim][TfO]2/CF3SO3H was finally determined as the best catalytic system.The reaction conditions were optimized,and the best reaction conditions were finally obtained:VTfOH:VIL=3:10,T=45?,t=30 min,RS=600 rads/min.The single reaction conversion rate was 93.77%,and the selectivity was as high as 74.63%.After the reaction,the product and the ionic liquid can be naturally separated.After the reaction,the[Bim-PPG 2000-Bim][TfO]2/CF3SO3H catalytic system is reused for multiple cycles to explore its recycling effect.Finally,it was found that after 5 cycles,the catalyst was basically deactivated,and the first 5 catalysiss could still maintain a high catalytic activity,and after 5 times,the activity decreased rapidly.In terms of the viscosity and color of the ionic liquid after recycling,the viscosity decreases and the color deepens,which indicates that the reason for the rapid deactivation of the polypropylene glycol ionic liquid catalyst system is also the dissolution of a large amount of acid-soluble oil.Polyetheramine type ionic liquid catalyst system:Polyetheramine with different polymerization degrees is used as the parent,1,3-propanesulfonic acid lactone is used as the sulfonating agent,and trifluoromethanesulfonic acid is used as the anion supply agent.A series of polyetheramine-type ionic liquid catalysts.Their structures are analyzed and characterized by infrared,nuclear magnetic and other analytical methods,and their thermal stability is analyzed by thermogravimetry.At the same time,in order to verify the unique solubilizing effect of polyetheramine-type ionic liquids on the alkylation raw material gas,the ionic liquid after the reaction was photographed for the first time through a high-power microscope,and bubbles were observed to further verify its solubilization.Polyetheramine ionic liquid and CF3SO3H were then applied to the isobutane/isobutylene alkylation reaction.The alkylation reaction was performed in an autoclave,and the reaction products were qualitatively and quantitatively analyzed by GC-MS and GC.Finally,[PS-PEA 2000-PS][TfO]2/CF3SO3H was determined as the optimal catalytic system.Under the optimal reaction conditions of VTfOH:VIL=3:10,T=25?,normal pressure,t=25 min,RS=600 rads/min,the conversion rate of alkylation reaction can reach 99.57%,The selectivity can reach 86.63%.Polyetheramine ionic liquid catalyst system can reach 14 times for the first time and 5 times for regeneration cycle.In this paper,Three ionic liquid catalysts with different structures were synthesized,and they were combined with trifluoromethanesulfonic acid to form a catalytic system for catalyzing the isobutane/isobutene alkylation reaction.By analyzing and comparing the catalytic results,it was finally determined that the[PS-PEA 2000-PS][TfO]2/CF3SO3H catalytic system has the best catalytic effect.In addition,the recycling and recycling of the catalytic system,as well as the solubilization of the reactants and the natural separation from the products were also explored.The study has shown that polyether ionic liquids as catalysts can not only catalyze reactions well,but also reduce the amount of acid and increase the reuse rate of acids.They are also environmentally friendly and renewable.Therefore,by studying the polyether ionic liquid in the alkylation reaction,it has opened a new way for the application of the ionic liquid in the alkylation reaction. |
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