Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction

碩士 === 國立中正大學 === 化學工程研究所 === 107 === Biodiesel can be prepared from vegetable oil and methanol by transesterification, and the alkaline catalyst is usually added to catalyze the reaction. Its reaction is influenced by water in reactants because the triglyceride were be hydrolyzed to form long carbo...

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Main Authors: LIANG,LING-WEI, 梁玲瑋
Other Authors: CHANG,JEN-RAY
Format: Others
Language:zh-TW
Published: 2019
Online Access:http://ndltd.ncl.edu.tw/handle/bx8mwx
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spelling ndltd-TW-107CCU000630142019-10-30T05:41:07Z http://ndltd.ncl.edu.tw/handle/bx8mwx Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction 抑制轉酯化觸媒活性基流失之研究 LIANG,LING-WEI 梁玲瑋 碩士 國立中正大學 化學工程研究所 107 Biodiesel can be prepared from vegetable oil and methanol by transesterification, and the alkaline catalyst is usually added to catalyze the reaction. Its reaction is influenced by water in reactants because the triglyceride were be hydrolyzed to form long carbon chain free acids, then it can make saponification reaction with alkaline catalyst. Therefore, the conversion and the yield of biodiesel were be reduced, and the produce emulsification cause a problem in products that are difficult to separate and purify. In this study, the alkaline pellet catalysts, MgO/SiO2(Q30), were prepared by incorporating Mg(NO3)2 into granular SiO2(Q30) followed by calcination in air at 500℃. These catalysts were tested by soybean-oil transesterification with methanol at 200℃ with methanol to oil ratio (mole) of 6:1, respectively. Cycling test results indicated that conversion at 2nd cycle is at 87.6% and that at 5th cycle is 78.7% and the MgO leached amont is 41.8mg/kg. Catalyst deactivation is mainly caused by MgO leached in reaction, because MgO is easily dissociated, resulting in defects of the catalyst structure and degrad the activity. The catalyst deactivation, however, can be suppressed by the addition of B(OCH3)3 to reaction. From previous studies, we know that B(OCH3)3 contribute to the formation of the product FAME and can be recovered by azeotropy. Experiment result showed that the addition of 5Wt% of B(OCH3)3 to reaction system, no catalyst deactivation was observed, while only 0.1Wt% was added, conversion decreased about 87.2% at the 2nd cycle, because B(OCH3)3 can effectively reduce the Mg2+ loss from the catalyst MgO/SiO2 (Q30). Synchrotron XRPD and FT-IR showed that -OCH3 from B(OCH3)3 react with Mg2+ to form Mg(OCH3)2 on catalyst surface ,which increases catalyst hydrophobicity thereby greatly inhibiting the formation of Mg(OH)2 and the corresponding Mg2+ leaching. CHANG,JEN-RAY 張仁瑞 2019 學位論文 ; thesis 98 zh-TW
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language zh-TW
format Others
sources NDLTD
description 碩士 === 國立中正大學 === 化學工程研究所 === 107 === Biodiesel can be prepared from vegetable oil and methanol by transesterification, and the alkaline catalyst is usually added to catalyze the reaction. Its reaction is influenced by water in reactants because the triglyceride were be hydrolyzed to form long carbon chain free acids, then it can make saponification reaction with alkaline catalyst. Therefore, the conversion and the yield of biodiesel were be reduced, and the produce emulsification cause a problem in products that are difficult to separate and purify. In this study, the alkaline pellet catalysts, MgO/SiO2(Q30), were prepared by incorporating Mg(NO3)2 into granular SiO2(Q30) followed by calcination in air at 500℃. These catalysts were tested by soybean-oil transesterification with methanol at 200℃ with methanol to oil ratio (mole) of 6:1, respectively. Cycling test results indicated that conversion at 2nd cycle is at 87.6% and that at 5th cycle is 78.7% and the MgO leached amont is 41.8mg/kg. Catalyst deactivation is mainly caused by MgO leached in reaction, because MgO is easily dissociated, resulting in defects of the catalyst structure and degrad the activity. The catalyst deactivation, however, can be suppressed by the addition of B(OCH3)3 to reaction. From previous studies, we know that B(OCH3)3 contribute to the formation of the product FAME and can be recovered by azeotropy. Experiment result showed that the addition of 5Wt% of B(OCH3)3 to reaction system, no catalyst deactivation was observed, while only 0.1Wt% was added, conversion decreased about 87.2% at the 2nd cycle, because B(OCH3)3 can effectively reduce the Mg2+ loss from the catalyst MgO/SiO2 (Q30). Synchrotron XRPD and FT-IR showed that -OCH3 from B(OCH3)3 react with Mg2+ to form Mg(OCH3)2 on catalyst surface ,which increases catalyst hydrophobicity thereby greatly inhibiting the formation of Mg(OH)2 and the corresponding Mg2+ leaching.
author2 CHANG,JEN-RAY
author_facet CHANG,JEN-RAY
LIANG,LING-WEI
梁玲瑋
author LIANG,LING-WEI
梁玲瑋
spellingShingle LIANG,LING-WEI
梁玲瑋
Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction
author_sort LIANG,LING-WEI
title Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction
title_short Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction
title_full Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction
title_fullStr Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction
title_full_unstemmed Suppression of MgO/SiO2 Catalyst Deactivation in Vegetable Oil Transesterification Reaction
title_sort suppression of mgo/sio2 catalyst deactivation in vegetable oil transesterification reaction
publishDate 2019
url http://ndltd.ncl.edu.tw/handle/bx8mwx
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