Title:
New synthetic methods to alter catalytic properties of supported K/MoS₂ catalysts for syngas conversion to higher alcohols

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dc.contributor.advisor Jones, Christopher W.
dc.contributor.advisor Agrawal, Pradeep K.
dc.contributor.author Okatsu, Hiroko
dc.contributor.committeeMember Sievers, Carsten
dc.contributor.committeeMember Sholl, David
dc.contributor.department Chemical Engineering
dc.date.accessioned 2013-09-19T13:03:33Z
dc.date.available 2013-09-19T13:03:33Z
dc.date.issued 2012-07-05
dc.description.abstract The purpose of this study is to develop catalysts for conversion of synthesis gas (H₂ and CO) to higher alcohols, primarily ethanol and propanol. Crude oil is consumed at a rate of more than 20 million barrels a day in the United States, mainly for producing fuels and chemical feedstocks. However, the total amount of crude oil is limited, and alternative ways of producing alcohols as precursors for chemical feedstocks are desirable. In this study, using a known K/MoS₂/metal oxide catalyst as the starting point, two different approaches were explored to improve catalytic properties: 1) Co promotion on K/MoS₂/mixed metal oxide (MMO) catalysts, and 2) Preparation of K/MoS₂/metal oxide catalysts with molybdenum carbide as a precursor, instead of molybdenum oxide. With respect to Co promotion on K/MoS₂/MMO catalysts, the effect of varying the Co content in the K/Mo-Co/MMO catalysts prepared by a co-impregnation method did not produce significant changes in catalytic acitivities or selectivities. It was due to the premature precipitation of cobalt molybdate during synthesis. Cobalt molybdate precipitation can generally be prevented by using water as a solvent, but this approach is not appropriate for this study because of the use of hydrotalcite-derived mixed metal oxide as the support. Co loadings on K/Mo/MMO-Co catalysts did not change selectivities significantly, either. However, they changed catalytic activities, represented by gas hourly space velocity (GHSV) required to obtain 8% conversion while maintaining high selectivities for higher alcohols. As a result, C ₂₊ alcohol productivities reached 0.01g(alcohol)/g(catalyst)/hr with Co loadings higher than 8%. With respect to using Mo2C as the precursor of Mo species instead of MoO3, comparisons between catalysts with different precursors for Mo species and different pretreatments were investigated. In this study, both K/Mo catalysts supported on MgO and α-Al₂O₃ showed similar tendencies of catalytic activities and selectivities. The highest C₂₊ alcohol selectivities and productivities were obtained on presulfided MoO₃ catalysts on both supports. In comparison of K/Mo ₂C catalysts with different pretreatments, higher C₂₊ alcohol selectivities and lower MeOH selectivities were obtained on presulfided catalysts compared to non-pretreated catalysts.
dc.description.degree M.S.
dc.identifier.uri http://hdl.handle.net/1853/48996
dc.language.iso en_US
dc.publisher Georgia Institute of Technology
dc.subject Molybdenum sulfide
dc.subject Molybdenum carbide
dc.subject Hydrotalcite-derived mixed metal oxide
dc.subject Cobalt
dc.subject Higher alcohols
dc.subject Syngas
dc.subject.lcsh Synthetic fuels
dc.subject.lcsh Gasoline, Synthetic
dc.subject.lcsh Catalysts
dc.subject.lcsh Ethanol as fuel
dc.subject.lcsh Propanols
dc.title New synthetic methods to alter catalytic properties of supported K/MoS₂ catalysts for syngas conversion to higher alcohols
dc.type Text
dc.type.genre Thesis
dspace.entity.type Publication
local.contributor.advisor Jones, Christopher W.
local.contributor.corporatename School of Chemical and Biomolecular Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 27088bc0-032b-40d1-b0a7-7f2f25b5bdeb
relation.isOrgUnitOfPublication 6cfa2dc6-c5bf-4f6b-99a2-57105d8f7a6f
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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