Preparation, Characterization And Catalytic Application Of Sulfonated Polyaniline Solid Acid

Polyaniline (PANI) is a kind of polymer material with special optical and electrical properties. It is widely used in anti-shielding, anti-corrosive, antistatic, conductive and catalytic materials. In recent years, the application of modified polyaniline is a hot spot for researchers, especially in the field of catalysis and electrochemistry. Therefore,a new sulfonated polyaniline solid acid catalyst was prepared by using polyaniline as carbon source and nitrogen source as substrate,and its catalytic performance was studied. The main contents and results are as follows:1. The sulfonated hollow polyaniline solid acid catalyst was prepared by emulsion polymerization using polystyrene as the soft membrane plate, the aniline monomer as the carbon source and the nitrogen source, ammonium persulfate as the initiator and the solid SO3 as the sulfonating agent. The results show that the polyaniline solid acid has a smooth hollow core-shell structure when the amount of aniline monomer is 1 mmol and the amount of ammonium persulfate is 1: 1. At the same time, with the increase of the amount of aniline monomer and the increase of the sulfonation temperature, the hollow spherical polyaniline solid acid gradually ruptured and collapsed, and no longer had a complete hollow core-shell structure. By controlling the amount of aniline and concentrated sulfuric acid sulfonation temperature, the control of the morphology and particle size of polyaniline solid acid of hollow sphere was successfully achieved.2. The prepared hollow spherical polyaniline matrix was subjected to liquid sulfonation in a sulfonating agent. The sulfonation was carried out using solid SO3 in an organic solution of 1,2-dichloroethane. After sulfonation at room temperature for 1h,a sulfonated hollow sphere polyaniline solid acid catalyst was obtained. They were characterized by SEM, TEM, XRD, IR, XPS and TG. The results of IR and XPS show that the S/N ratio of polyaniline surface increases from 0.5 to 3.0 before sulfonation. The results of SEM, TEM and XRD show that the morphology of polyaniline after sulfonation is more regular and the surface of the hollow sphere is more complete and smooth,and no spherical collapse occurs. TG results show that the sulfonated polyaniline has good thermal stability at 25??250?.3. The effects of sulfonated hollow polyaniline solid acid (h-SPAN) on the indole group reaction were studied. The results showed that the yield of indol -based compounds was 70%?93.9% when the amount of catalyst was 20mmol%, the ratio of ethanol to water was 1: 9, the reaction temperature was 30?,the reaction time was 10?60min. After the catalyst was used four times,the yield was reduced to below 70%.4. The prepared sulfonated polyaniline-based activated carbon-based solid acid SPAN@AC was applied to the microwave synthesis of Schiff base probe reaction. The results showed that when the microwave power was 400W,the reaction time was 3?20min,the amount of catalyst (mole fraction)was 5%, the ethanol was used as the solvent,the yield of Schiff base was 80?93%,and the catalyst activity was repeated 5 times and the activity began to decrease, and indicating that the catalyst has good catalytic activity and stability.5. The solid acid SPAN@AC was applied to the catalytic reaction of the synthesis of cyclohexanone glycerol ketal. The results showed that when the molar ratio of cyclohexanone to glycerol was 1: 1.2 (0.1 mol of cyclohexanone), the mass fraction of catalyst was O.lg, the water carrying agent was 10 mL and the reaction time was 90 min. The yield reached 96.5% and the selectivity was greater than 98.0%. After 5 times of repeated use of the catalyst,the activity began to decrease.6. Through the investigation of the activity of catalyst h-SPAN and SPAN@AC, it is shown that both catalysts have good catalytic activity and stability. The catalyst h-SPAN is a super-hydrophilic solid acid and is suitable for the aqueous phase catalytic reaction. The catalyst SPAN@AC is a hydrophobic solid acid and can only be used as an organic phase catalyzed reaction.