Study On The Etherification Of Glycerol With Light Olefins

Every year, about300000tons of glycerol was produced as byproduct in the process ofbiodiesel and lipid production. Glycerol is undergoing the change from end product tochemical raw material. It is a challenge to develop a new way of making use of glyceroleffectively to reduce the cost of biodiesel production. The side product C4component hassurpassed3.0Mt/a during the process of petroleum catalytic pyrolysis and naphtha pyrolysisto produce ethylene.In this paper, glyceryl tert-butyl ethers were synthesized using glycerol and isobutylene asfeedstock. The factors, such as the mol ratio of material, temperature, pressure, reaction timeand stirring rate, which influencing the glyceryl tert-butyl ether product distribution and yieldwere studied. GC-MS and FT-IR were applied to analyze the product qualitatively andquantitatively. The optimized reaction conditions to synthetize glyceryl tert-butyl ethers were:glycerol: isobutylene=1:4(mol ratio), reaction temperature100℃, reaction time5h, theinitial pressure3MPa, stirring rate400r/min, which was catalyzed by the solid acid HYBZ-2catalyst (7%of the glycerol mass). The total yield of monoether (MTBG), diether (DTBG)and triether (TTBG) was63.4wt%under the optimal synthesis condition. The purifiedglyceryl tert-butyl ether was blended with normal diesel by10∶90（V/V）and15∶85（V/V）,respectively. The main specifications of the blending diesel, such as cetane number, density,viscosity, flash point and distillation characteristics were measured in order to evaluate thefeasibility of taking glyceryl tert-butyl ether as cleaning additives in diesel. The researchshowed that the physicochemical specifications of the blending diesel can meet theGB19147-2009standard, and diether (DTBG) and triether (TTBG) mixture was proved to bethe most proper blend component or additive in the diedel.The Preliminary thermodynamic data of MTBG, DTBG, TTBG was canalog omputedusing professional ChemBioOffice software. The Cp, Cv,△H,△S,△G, ZPE and△U thermodynamic data were obtained by GAMESS module; The formation heats of monoether(MTBG), diether (DTBG) and triether (TTBG) were computed by MOPAC modulerespectively. Thermodynamic data were valuable for the fundamental research, industrialapplication, engineering design, the preparation of the PDP technology package of GTBE.Moreover, the glycerol amyl ether synthesis from glycerol and isobutylene was studiedin this thesis. The results indicated that the yield of glycerol amyl ether was merely2.46%.Various efforts, such as optimizing reaction codition, selecting different acid catalysts,solvents,were failed to increase the yield, and the product distribution can not be improved.The reason maybe that there are three hydroxy groups in glycerol molecular structure, andisoamylene is bigger than isobutene in molecular dimension, so there is certain sterichindrance between hydroxy groups and isoamylene molecule.