Research Of Catalytic Synthesis Of Oligo-Glycol Ethers From Coal-Derived Ethylene Glycol And Methanol

The energy characteristics of“coal richness,oil and gas shortage”of China determines that coal chemical industry plays a key role in national energy security.Ethylene glycol and methanol,the bulk chemicals of coal chemical,has been urgently needed to develop high value-added downstream products.Oligoethylene glycol ether has a large market gap as diesel additive,aprotic solvent,printing and dyeing auxiliaries,especially as a diesel fuel additive,it has prosperous outlook.This project is aimed to synthesize oligo-glycol ethers from ethylene glycol?EG?and methanol on fixed-bed reactor by solid acid catalysts.The main works are as follows:?1?Using ethylene glycol and methanol as raw materials directly to study the feasibility by testing reaction conditions,solid acid catalysts via method of lateral comparison using single factor test.The best effect among them was emerged by H?catalyst,where EG's conversion was up to 92.5%and ethylene glycol?di?methyl ether selectivity were 39.4%,while higher molecular weight products like di-and triethylene glycol?di?methyl ether selectivity were less than 0.5%at testing conditions.?2?The oligomeric glycol was synthesized from ethylene glycol,the solid acid catalyst was screened,the reaction conditions were tested by method of single factor,the catalysts was modified by different types and concentrations of salts of ammoniums and metals.It demonstrated that HY zeolite which was modified with 0.2mol/L?NH₄?₂SO₄ and then treated with 2.0wt%Cu exhibited the highest activity where the EG's conversion was 51.0%,and the total selectivity of di-and triethylene glycol were 80.8%at the temperature of 230?,pressure of 2.0 MPa,WHVS of 1.8h^-1,and carrier gas flow rate of 40 ml/min.?3?Synthesis of diethylene glycol?di?methyl ether from diethylene glycol and methanol.The catalysts were screened and the single-factor and orthogonal tests on the reaction conditions were carried out,and the time-on-stream test of 100-hour was performed.It eventually showed that A-2 resin has the highest activity where DEG's conversion was up to 81.3%,and total selectivity of diethylene glycol?di?methyl ether were 60.3%,time-on-stream test illustrated that the resin catalyst possess excellent stability.The optimal reacting conditions group is temperature of 160?,pressure of 2.5 MPa,WHVS of 1.8h^-1,the carrier gas flow rate of35ml/min,and the molar ratio of DEG/methanol was 6:1.?4?Using the mixture of the product of the second step and methanol as raw materials,took the conditions of the third step to perform the joint tests to synthesize the final product.It shows that the final conversion of EG was 99.9%,total selectivity of oligo-glycol ethers were71.5%in which glycol ethers,diethylene glycol ethers,triethylene glycol ethers account for51.9%,17.1%and 2.5%respectively,which still has much room for improving.The product was subjected to simulated rectification separation.The results demonstrate that the system have complex azeotropes.The pervaporation-rectification coupling maybe better purifying method.