Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol

The strong growth of biodiesel production has led to a significant increase in glycerol, the by-product of the process. Therefore, this study focused into converting glycerol to high-value chemical which is 1,2-propanediol over heterogeneous catalyst. Metal supported catalyst was synthesized usin...

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Main Author:	Azri, Norsahida
Format:	Thesis
Language:	English
Published:	2021
Subjects:	Copper catalysts Dolomite Hydrogenolysis
Online Access:	http://psasir.upm.edu.my/id/eprint/92817/1/FS%202021%2039%20-%20IR.pdf
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spelling	my-upm-ir.928172022-06-01T07:56:55Z Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol 2021-07 Azri, Norsahida The strong growth of biodiesel production has led to a significant increase in glycerol, the by-product of the process. Therefore, this study focused into converting glycerol to high-value chemical which is 1,2-propanediol over heterogeneous catalyst. Metal supported catalyst was synthesized using wet impregnation method, later calcined, and subsequently reduced under 5%H2 environment. The metals investigated were copper (Cu), nickel (Ni), cobalt (Co), zink (Zn) and iron (Fe) while the supports used were dolomite (Dol), alumina (Al2O3), bentonite (Bent), montmorillonite (Mont), and talcum (Talc). Results showed that copper supported on dolomite (Cu/Dol) gave the best catalytic activity in glycerol hydrogenolysis. Henceforth, different loadings of copper on dolomite were synthesized. Cu/Dol catalyst calcined at 500 ºC and reduced at 600 ºC exhibited the highest glycerol conversion of 78.5% and 1,2-PDO selectivity of 79% at 200 ºC reaction temperature, 4 MPa H2, 10 h reaction time, 20wt% glycerol concentration, and 1 g catalyst dosage. After optimization study, it was demonstrated that the glycerol conversion and 1,2-PDO selectivity was increased with the increasing reaction temperature, hydrogen pressure, reaction time, catalyst dosage, glycerol concentration and copper metal loading up to their optimum value. The results were optimized at copper loading of 20wt%, 180 ºC reaction temperature, 2 MPa hydrogen pressure, 6 h reaction time, 20wt% glycerol concentration, and 1 g catalyst dosage with maximum glycerol conversion of 100% and 1,2-PDO selectivity of 92.2%. It can be concluded that the high performance of 20%Cu/Dol catalyst was attributed to its macroporous and crystalline features, composed of mixed crystalline phases with calcium, magnesium, oxygen as main components, good copper surface area, copper dispersion and thermal stability. Also, the good copper-dolomite interaction, including high metal reducibility (~291 ºC) and very importantly the presence of its high acid capacity (19528 μmol/g) with Lewis sites on the catalyst surface as the active reaction sites. In addition, the incorporation of copper to dolomite presented a promising reaction performance rather metallic copper and dolomite alone attributed to its improved acidity and metal reducibility. On subjecting the 20%Cu/Dol to reusability study in five reaction cycles, it maintained good performance in glycerol conversion but inferior in 1,2-PDO selectivity after the first use. The evidence indicated that the reduced 1,2-PDO selectivity was due to the coke formation and leaching of metal active sites (Cu, Ca dan Mg). The conversion of glycerol to 1,2-PDO followed the dehydration–hydrogenation pathway while reaction towards C–C cleavage with methanol as side product was minimal. Copper catalysts Dolomite Hydrogenolysis 2021-07 Thesis http://psasir.upm.edu.my/id/eprint/92817/ http://psasir.upm.edu.my/id/eprint/92817/1/FS%202021%2039%20-%20IR.pdf text en public doctoral Universiti Putra Malaysia Copper catalysts Dolomite Hydrogenolysis Ramli, Irmawati
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
advisor	Ramli, Irmawati
topic	Copper catalysts Dolomite Hydrogenolysis
spellingShingle	Copper catalysts Dolomite Hydrogenolysis Azri, Norsahida Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol
description	The strong growth of biodiesel production has led to a significant increase in glycerol, the by-product of the process. Therefore, this study focused into converting glycerol to high-value chemical which is 1,2-propanediol over heterogeneous catalyst. Metal supported catalyst was synthesized using wet impregnation method, later calcined, and subsequently reduced under 5%H2 environment. The metals investigated were copper (Cu), nickel (Ni), cobalt (Co), zink (Zn) and iron (Fe) while the supports used were dolomite (Dol), alumina (Al2O3), bentonite (Bent), montmorillonite (Mont), and talcum (Talc). Results showed that copper supported on dolomite (Cu/Dol) gave the best catalytic activity in glycerol hydrogenolysis. Henceforth, different loadings of copper on dolomite were synthesized. Cu/Dol catalyst calcined at 500 ºC and reduced at 600 ºC exhibited the highest glycerol conversion of 78.5% and 1,2-PDO selectivity of 79% at 200 ºC reaction temperature, 4 MPa H2, 10 h reaction time, 20wt% glycerol concentration, and 1 g catalyst dosage. After optimization study, it was demonstrated that the glycerol conversion and 1,2-PDO selectivity was increased with the increasing reaction temperature, hydrogen pressure, reaction time, catalyst dosage, glycerol concentration and copper metal loading up to their optimum value. The results were optimized at copper loading of 20wt%, 180 ºC reaction temperature, 2 MPa hydrogen pressure, 6 h reaction time, 20wt% glycerol concentration, and 1 g catalyst dosage with maximum glycerol conversion of 100% and 1,2-PDO selectivity of 92.2%. It can be concluded that the high performance of 20%Cu/Dol catalyst was attributed to its macroporous and crystalline features, composed of mixed crystalline phases with calcium, magnesium, oxygen as main components, good copper surface area, copper dispersion and thermal stability. Also, the good copper-dolomite interaction, including high metal reducibility (~291 ºC) and very importantly the presence of its high acid capacity (19528 μmol/g) with Lewis sites on the catalyst surface as the active reaction sites. In addition, the incorporation of copper to dolomite presented a promising reaction performance rather metallic copper and dolomite alone attributed to its improved acidity and metal reducibility. On subjecting the 20%Cu/Dol to reusability study in five reaction cycles, it maintained good performance in glycerol conversion but inferior in 1,2-PDO selectivity after the first use. The evidence indicated that the reduced 1,2-PDO selectivity was due to the coke formation and leaching of metal active sites (Cu, Ca dan Mg). The conversion of glycerol to 1,2-PDO followed the dehydration–hydrogenation pathway while reaction towards C–C cleavage with methanol as side product was minimal.
format	Thesis
qualification_level	Doctorate
author	Azri, Norsahida
author_facet	Azri, Norsahida
author_sort	Azri, Norsahida
title	Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol
title_short	Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol
title_full	Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol
title_fullStr	Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol
title_full_unstemmed	Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol
title_sort	development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol
granting_institution	Universiti Putra Malaysia
publishDate	2021
url	http://psasir.upm.edu.my/id/eprint/92817/1/FS%202021%2039%20-%20IR.pdf
_version_	1747813774190968832

Development of dolomite-supported copper catalysts for glycerol hydrogenolysis to 1,2-propanediol

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