Study On Preparation Of Polyols Using Epoxidized Vegetable Oil With Catalysis Of Solid Phosphotungtsic Mesoporous Silica Sieves

On this basis of crisis of fossil fuels,it is important to develop environment-friendly and price-low biomass based chemicals to replace increasingly depleted chemical raw materials.The traditional polyols are based on petroleum material,it is nonrenewable,and its product can not be decomposed easily.It brings environmental pollution as well as fuel crisis.This thesis is focus on epoxidized soybean oil?ESBO?,with catalysis of phosphotungstic solid acid based mesoporous silica sieves HPW-MS and HPW/MS,ESBO were transferred to soybean oil-based polyols thorough hydroxyl.Catalyst preparation,effect on HPW loading in support versus conversion of polyols,effect on hydroxyl agents and effect on different traditional liquid catalysts had been studied.The research results are as following:?1?The phosphotungstic solid acid mesoporous silica sieves catalysts?HPW-MS and HPW/MS?were prepared by direct-synthesis and impregnation,respectively.HPW-MS and HPW/MS were characterized by FT-IR,N₂ adsorption-desorption,XRD,SEM,TEM,ICP-OES,NH₃-TPD and TG,as prepared HPW-MS and HPW/MS demonstrate characteristic peaks of HPW.Comparing to support,the catalysts remain mesoporous structure,HPW-MS have ideal BET surface of 736.1 m²/g,pore size of 5.5 nm and pore volume of 1.028 cm³/g;HPW/MS have BET surface of 535.2 m²/g,pore size of 5.3 nm and pore volume of 0.801 cm³/g.?2?The as-prepared HPW-MS and HPW/MS had been applied in hydroxyl model kinetic reaction of 1,2-Epoxydodecane?EDD?.In single factor experiments,effect on catalyst dosage,reactant ratio,reaction temperature and time versus conversion of EDD were discussed.In the kinetic study,the hydroxylated reaction of EDD meets up with the rule of second order kinetics reaction,and it demonstrates well linear realationship.The activation energy Ea=25.78 kJ/mol,the pre-experimental factor A=12083 s^-1.?3?The textural variation was studied between different HPW loading in HPW-MS and HPW/MS,and their performance in ESBO hydroxyl reaction were discussed.The effect on reactant ratio,time,catalyst usage and temperature were disscussed.The best protocol was obtained by single factor experiment:dosage of catalyst is 2 wt.%,reaction temperature is 65°C,reaction time is 3 h,reactant ratio of alcohol and ESBO is 11:1,the conversion of ESBO were 80.1%?HPW/MS?and 74.9%?HPW-MS?,respectively.The polyols were analyzed by FT-IR,MALDI-TOF,GPC,TG and DSC.In the recycle test of catalysts,HPW/MS presented obvious decreasing conversion after four times recycle,while HPW-MS still kept high conversion.Transesterified ESBO was prepared as raw material to synthesize methyl ester based polyols,it had a lower hydroxyl number than ESBO based polyols but lower viscosity,which is ideal material for preparing polyurethane based foam.?4?With catalysis of HPW-MS,hydroxyl agents were used as hydroxyl reagents to prepare soybean oil-based polyols.Me-Polyol presented biggest hydroxyl number,Et-Polyol was the second,the Ipa-Polyol was the last.TG results presented the polyols had higher decomposition temperature than starting material ESBO;GPC results showed Me-Polyol had most polymerization content,Et-Polyol was the second and Ipa-Polyol had least.?5?In comparison of liquid sulfuric acid,hydrochloric acid and phosphotungstic acid,these acid catalysts showed ideal performance in reaction and the polyols had high hydroxyl number.On the contrary,comparing to HPW-MS,it is easy to have side reaction using the liquid acid catalyst.With GPC analysis,the samples presented various range of molecular distributions,and the PDI values had decreasing range of H₂SO₄>HPW>HCl>HPW-MS.Comparing to the liquid acid catalysts,it seems there are less side reaction using solid HPW-MS as catalyst.