Modification Of The Sulfonated Polystyrene Resin And Its Catalytic Synthesis Of N-Butyl Acetate

N-Butyl acetate is an industrially important basic organic chemical, widely used in paints, varnishes, perfumes, etc. Traditional industrial synthesis of butyl acetate uses concentrated H2SO4as catalyst, but there are many deficiencies in the method:many side reactions, equipment corrosion, product purity not high, post-processing complicated and serious environmental pollution. Therefore, safe and environmentally friendly catalysts (such as solid acid) become the focus of the research in recent years. Compare to concentrated sulfuric acid catalyst, sulfonated polystyrene resin have been widely studied as catalysts for the synthesis of esters. But the resin tends to be inactivated when it exchanges the ions of raw material. The acid strength of resin is lower than the concentrated sulfuric acid. And the resin can become power in the condition of continuous production. All these problem greatly restrict the large-scale industrial applications of the resin.In this thesis, the macroporous sulfonic resin was selected as the carrier to prepare modified resin by the liquid-solid solvent method in ethanol solution of tin tetrachloride to improve resin’s ability. And the optimum process conditions of synthesizing n-butyl acetate by the modified resin were studied.The synthesis of n-butyl acetate has been studied as an example. The effects of the modification time, SnCl4dosage, washing method, and water separation on the activity of catalyst for esterification were studied. The optimal preparation conditions for the modified resin are as follows:D001-CC as the resin, modification temperature of78.3℃,10.71%(volume fraction) of the ethanol solution of tin tetrachloride, and modification time of6h. FTIR、XRF and XRD techniques were used to characterize the catalyst. Results show that SnCl4reacts with a-SO3H group of the resin to form a new Lewis acid center. In the conditions of continuous water separation, the modified resin has a better catalytic activity. When the resin and modified resin were treated by the aqueous solution which had metal ions, the catalytic activity of the modified resin were not change. The result proves that the modified resin is not inactivated when it encounters metal ions.The process conditions of n-butyl acetate synthesis catalyzed were studied by the modified resin. By the single factor and orthogonal experiments, the optimum conditions for the synthesis are as follows:the molar ratio of acetic and butanol is1:1.5, the reaction temperature is115℃, the amount of catalyst is6g/mol(HAc), reaction time is80min, and the acetic acid conversion can reach99.01%. In the conditions of continuous water separation, the catalytic activity of the modified resin can keep stable and highly active. Acetic acid conversion can reach98.56%in70minutes and the catalyst can be reused at least10times. Based on this research, the process of catalytic distillation of butyl acetate synthesis with modified resin was studied. The appropriate results are obtained when the mole ratio of raw materials (Bu:Ac) is1.3, the reaction time is50min, and the acetic acid conversion rate approximate97.8%.This result provides some basis data for the industrial production.