Preparation Of Carbon-based Solid Acid Catalysts And Catalytic Performance Of Tetrahydrofuran Polymerization

Polytetrahydrofuran is a polyether diol containing two hydroxyl functional groups,polymerized by catalytic Tetrahydrofuran monomer,and the molecule has a linear structure.The average molecular weight of about 2000 Polytetrahydrofuran is mainly used to synthesize spandex.When the product is industrialized,fuming sulfuric acid,acetic anhydride-perchloric acid or Fluorosulfonic acid as initiators to promote the polymerization of Tetrahydrofuran.However,such processes have serious problems such as corrosion installation and excessive contamination.In order to overcome the limitation of homogeneous catalysis,people began to explore the catalysts for the polymerization of Tetrahydrofuran.In this thesis,Nafion modified carbon-based solid acids were prepared and characterized and the effects of solid acid catalyst structure,texture and acidity on the polymerization of Tetrahydrofuran were investigated.This paper mainly works from the following two aspects:(1)To study the preparation and catalytic THF polymerization of different Nafion modified glucose carbon-based solid acids;(2)Preparation of chitin doped Nafion-carbon-based solid acid and catalytic THF polymerization.Around the above two aspects,we researched the preparation of the modified Nafion glucose carbon-based solid acid and catalytic THF polymerization firstly.The effects of catalysts with different Nafion contents and different calcination temperature for the THF polymerization were investigated.Afterward introduced chitin by hydrothermal synthesis method,template method,impregnation method to prepared carbon-based solid acid catalysts and explored their catalytic performance for THF polymerization.All catalysts were characterized by N2 physical adsorption-desorption,X-ray diffraction(XRD),Fourier Transform infrared spectroscopy(FT-IR)and Acid titration.The results show the catalysts have a sulfonic acid group(-SO3H)that belongs to the amorphous carbon type.As the Nafion contents increasing,the acid contents increases,the yield of Polytetrahydrofuran tends to balance,and the relative molecular weight decreases.In addition,the increase of temperature also resulted in the decrease of acid quantity,the yield of Polytetrahydrofuran increased and the molecular weight decreased.The ratios of glucose/shell powder increased,the yield of Polytetrahydrofuran increased,molecular weight increased.However,the premise is the amount of shell powder isn't greater than the amount of glucose.The addition of shell powder has better catalytic activity for the THF polymerization than the catalyst without the shell,and the yield of the polymer is higher.It is concluded that doping chitin is an important method for regulating the acidity ofNafion modified glucose carbon-based solid acid.