Lubricant from 1-decanol via oligomerization reaction over novel heterogeneous catalysts

Name: Snunkhaem Echaroj

keyword: Oligomerization

; Heterogeneous acid catalyst

; C13-NMR

; Micro-kinetic analysis

; Synthetic lubricant

Abstract: The oligomerization of olefins to heavier hydrocarbons with lubricant-like properties was investigated over different acid heterogeneous catalysts including Beta-38, Mordenite-20, HY-30 and tungstated-zirconia. Textural characterization was performed using N2 sorption technique and X-ray diffraction (XRD). Acidity of the catalysts were found using the temperature-programmed desorption (TPD) of NH3 Among the zeolite catalysts, HY-30 zeolite gave the highest amount of lubricant due to high acidity, large pore size and cage-like framework of catalyst. Operating parameters that have a significant effect on the formation of lubricant were reaction temperature and the amount of catalyst. Over HY-30 zeolite, an increase in temperature from 150 to 210 oC was found to increase 1-decene conversion from 60 to 87 wt% and amount of lubricant from 5 to 25 wt%. An increase in the amount of HY-30 used from 5 to 15 wt% resulted in an increase in conversion from 40 to 80 wt% and amount of lubricant from 1 to 18 wt%. An increase in conversion was accompanied by a reduction in viscosity index of the lubricant products. Investigation of oligomer structure using C13-NMR analysis revealed oligomers with low viscosity index consisting of high composition of short-chain branches. A reduction in viscosity index from 150 to 104 resulted in a rise in the amount of short-chain-branches from 28 to 48 %. Conversion of double-bond oligomers to saturated molecule via hydrogenation reaction over 1%Pt/Al2O3 catalyst was confirmed by using Fourier Transform Infrared Spectroscopy (FTIR). Catalyst modification can be performed to increase catalytic activity, pore size and reduce acidity of the catalysts. Three different methods were employed to modify zeolite catalysts including fluorination, ion-exchange of cation and Ni metal incipient impregnation. Modification of Beta-38 zeolite through the fluorination process resulted in an improvement in catalytic activity, but reduction in viscosity index of the oligomers. Ion-exchange was successfully performed to expand the pore of the Beta-38 zeolite causing the viscosity of the oligomer product to increase from 100 to 140. A micro-kinetic analysis of the oligomerization reaction over tungstated-zirconia catalyst was also conducted to study the mechanism of oligomerization of 1-decene. The optimal condition resulted in 1-decene conversion of 70 % and product consisting of 49 % dimers and 23 % trimers. Dimerization and trimerization reactions required apparent activation energy of 21 and 33 kJ/mol, respectively. Trimerization reaction was found to proceed through the combination of dimer and monomer molecules. According to the modeling equation, the dimerization reaction required two active sites at low temperature and three active sites at high temperature. For trimerization reaction three active sites were required at low temperature and four active sites at high temperature. The best modeling equation fitted appropriately with the experimental data

Thammasat University. Thammasat University Library

Address: BANGKOK

Email: preserv@tu.ac.th

Name: Malee Santikunaporn

Role: advisor

Created: 2016

Modified: 2021-07-29

Issued: 2021-07-29

วิทยานิพนธ์/Thesis

application/pdf

DOI: 10.14457/TU.the.2016.1328

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Engineering

Grantor: Thammasat University

©copyrights Thammasat University

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