Study On Synthesis Of Alkaline Mesoporous Molecular Sieves SBA-15 And The Catalyticalcoholysising Performance For Polycarbonate

Mesoporous materials are expected to improve the traditional acid-base catalytic system as a new template and catalyst,which are the focus of the current research direction.In this paper,BaO,SrO and CaO were supported on the mesoporous molecular sieve SBA-15.Different kinds of basic mesoporous materials were designed and synthesized.The reaction was carried out under the given conditions.polycarbonate material was alcoholysised.To achieve the recycling of mesoporous materials,Overcome the shortcomings of the traditional catalyst can not be reused,corrosion equipment,large amount of waste produce.The method can provide reference for the recycling process of waste polycarbonate materials for alkaline mesoporous materials,and provide a new process for the recovery of waste polycarbonate materials to recover high purity monomer.In this paper,the catalyst BaO-SBA-15,SrO-SBA-15 and CaO-SBA-15 were prepared by impregnation method with SBA-15 as the carrier by hydrothermal synthesis method.In addition,X-ray powder diffraction?XRD?,N2adsorption-desorption,Fourier transform infrared spectroscopy?FT-IR?,CO₂-programmed desorption?CO₂-TPD?and other technical means were used to characterize the prepared molecular sieves.The results show that SBA-15 has a high degree of ordered pore structure,better pore size and crystallinity,pore composition and properties are stable,and some alkaline components have existed on SBA-15,so that SBA-15 has Alkali catalytic activity.K₂O-CaO-SBA-15 was obtained by loadingdifferent amounts of K₂O on the carrier with CaO-SBA-15 as the carrier.X-ray powder diffraction?XRD?,N₂ adsorption-desorption,Fourier transform infrared spectroscopy(FT-IR and CO₂-temperature desorption?CO₂-TPD?were used to characterize the structure.The results show that when the K₂O loading increases,the order of SBA-15 will decrease,and when the K₂O loading exceeds 9%,the SBA-15 pore is blocked and the alkaline components Of the reunion,there is a larger crystal.At the same time,after the K2 O,the pore surface of CaO-SBA-15,compared with the surface area,the change of these pore faces is obvious.The basic strength of CaO-SBA-15 will also be greatly affected by the change in the amount of K₂O,depending on the temperature rise and desorption from the CO₂ process.The synthesized alkali modified zeolite was used as catalyst to catalyze the alcoholysis of PC methanol,and then the catalytic activity of molecular sieve was studied in depth.In addition,the recovery performance of the molecular sieve was also discussed.The effect of different reaction conditions on the alcoholysis reaction was investigated in detail.CaO-SBA-15 was screened out.The effect of different CaO loading on the alcoholysis of PC was investigated.The results showed that CaO-SBA-15 had better catalytic effect when CaO loading was 10%.In addition,the influence of the reaction time and the reaction temperature,the amount of THF and the amount of methanol on the alcoholysis reaction of PC were also analyzed.The orthogonal experiment was used to investigate the primary and secondary factors of four factors: the amount of catalyst> the amount of THF> the amount of methanol>temperature.The reaction conditions were as follows: n?methanol?: n?PC?= 8: 1,n?tetrahydrofuran?: n?PC?= 7: 1,reaction temperature 130 ?,reaction time 3 h,30%?the ratio of catalyst to raw material?,the conversion and yield were 98.7% and 96.8%,respectively.The structure of PC alcohol was analyzed by FT-IR.The results of molecular sieve recycling showed that the conversion of PC and the yield of BPA did not change significantly after 5 times of continuous use.XRD technique was used to characterize the CaO-SBA-15 before and after repeated use.It was confirmed that the chemical structure of CaO-SBA-15 did not change after 5 times,and the PC alcoholysis reaction under CaO-SBA-15 catalyzed The reaction mechanism was studied.The K₂O-CaO-SBA-15 modified mesoporous molecular sieves was used as catalyst to catalyze the alcoholysis of PC methanol,and the repeated reuseperformance of the molecular sieves was investigated.The effects of K₂O loading The results showed that the catalytic conditions of 9% K₂O-CaO-SBA-15 were the best.In addition,the effect of K₂O-CaO-SBA-15 on the PC alcoholysis reaction was also analyzed when the reaction time and temperature,the amount of THF and the amount of methanol were used.The optimum reaction conditions were as follows: reaction temperature was 100 ?,reaction time was 2h,n?methanol?: n?PC?= 8: 1,n?tetrahydrofuran?: n?PC?= 7: 1,20%,the conversion and yield were 100% and 97.5%,respectively.The results of K2O-CaO-SBA-15 cycle showed that the conversion of PC and the yield of BPA did not decrease significantly after 5 times of repeated use.The K₂O-CaO-SBA-15 was characterized by XRD technique.The results showed that the chemical structure of K₂O-CaO-SBA-15 did not change significantly before and after repeated use.The above research content is not reported in the literature.