Properties And Application Of Four Hydroxyl Class Functionalized Modification Porous Materials

In order to improve the adsorption performance of porous adsorption materials,functional modification is an ideal approach which was developed quickly in recent years.There are a few research that design and preparation of functional modification materials aiming at specific structural features of active components from natural products.However,what kind of modified groups should be introduced,why were such groups,these problems have not been very good interpreted.So the traditional porous adsorption materials have some insufficient such as poor selectivity and low efficiency of separation and purification.Therefore,to improve the isolation and purification efficiency and selectivity absorption for active components from complex natural products,tailor design and preparation functional porous adsorption materials was proposed.It is a new opportunity to development separation and purification technology especially for active components from complex natural products.In this paper,polyphenols compounds were selected as the target components,which have structure characteristics of the polyphenols hydroxyl,polystyren(PS)was selected as matrices.Four hydroxyl class groups were introduced as modified groups based on structural characteristics of polyphenols hydroxyl,such as hydroxyl,phenol,resorcinol and hydroquinone.The structure–activity relationship of functional modified materials and adsorption performance was investigated in detail.The influencing factors of adsorption and separation rules about hydrogen bond and ?-? interaction were systematically analyzed.The influence of adsorption and separation rules about hydrophily and size exclusion effect on functional modified materials were discussed.The adsorption mechanism was carried on the deep discussion.The results showed that:(1)Chloromethylated-PS(X0)as matrix,the hydroxyl modified adsorbents were prepared by methyl chloride hydrolysis reaction under alkaline condition,where the aperture of adsorbents has no any change.Phenol,resorcinol and hydroquinone modified adsorbents were prepared by Friedel–Crafts catalyzed process,which can form different spatial structure on the functional modified porous adsorbents due to different modified group under same reaction mechanism.Meanwhile,the specific surface area was greatly increased.(2)Stibene glucoside(TSG)as polyphenols compound was selected as the model components,which was extracted from Polygonum multiflorum root.It was noted that the adsorption capacity and retention behavior of functional adsorbents to TSG depend on the specific surface area,hydrophilia,hydrogen bond,?-? interaction between adsorbent and absorbate,and better geometrical matching between absorbate and spatial structure of adsorbents micropore.In addition,the hydrophilia and better geometrical matching can make functional adsorbents exhibit excellent selective adsorption performance.The structure–activity relationship of functional modified materials and adsorption performance was established.(3)Adsorption mechanism of hydroxyl class functional modified materials was systematically analyzed about hydrogen bond and ?-? interaction.The results showed that adsorption kinetics of X1 and X2 follow the pseudo-second-order kinetic model,while X3 and X4 follow the pseudo-first-order kinetic model.The results also indicated that all equilibrium adsorption data best fit the Langmuir model.The positive values of ?H indicated that all the test adsorption processes are endothermic process.The negative values of ?G indicated that adsorption processes of X2 was exothermic,favorable and spontaneous.Others adsorption processes need additional energy.These results showed that hydrogen bond and ?-? interaction have little effect on adsorption kinetics and equilibrium adsorption,while geometrical of functional groups impacts on adsorption behavior of TSG.Meanwhile,TSG was separated successfully onto X2 and X4 adsorbents packed columns in a gradient eluent process.The purity of TSG was 10.9-fold increased from 8.12% to 88.53% with a recovery of 79.76%.(4)The factors influencing of pore structure and distribution were proposed in functional modified Friedel–Craft catalyst reaction due to post-polymerization crosslinking reaction.The results showed that new pore structure should be formed in post-polymerization crosslinking reaction within 4h,while it was not the only factor.Phenol and hydroquinone participate in Friedel-Craft catalyst reaction,where more pore structure should be produced.However,resorcinol participate in Friedel-Craft catalyst reaction against forming new pore structure.(5)(-)-Epigallocatechin gallate(EGCG)and caffeine(CAF)were chosen as model components which were extracted from green tea.The purpose of this work was to develop and assess adsorption behavior and adsorption mechanism about hydrophily and size exclusion effect.The results indicated that hydrophily was beneficial to contact between adsorbent and absorbate.Porosity and more specific surface area can improve adsorption capacity,especially for small molecule CAF has more influence.It was difficulty to separate and purify EGCG and CAF by hydrophily,hydrogen bond,and ?-? interaction.Only in this case,synergistic effect resulted from hydrophily and size exclusion effect could be obtained.Simultaneously,EGCG and CAF could be separated on the X4 adsorbents packed columns in a gradient eluent process.It is shown that the adsorption kinetics of EGCG and CAF followed the pseudo-second-order kinetic model on the X4 adsorbents.The results also indicated that the equilibrium adsorption data best fit the Langmuir model on X4 adsorbents.