東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back to Search results for [ null ]

Switch To: Labeled | MARC Mode | ISBD

Alcohol synthesis from carbon-monoxi...

Santiesteban, Jose Guadalupe,

Linked to FindBook

Google Book

Amazon

博客來

Alcohol synthesis from carbon-monoxide and hydrogen over molybdenum-disulfide based catalysts /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Alcohol synthesis from carbon-monoxide and hydrogen over molybdenum-disulfide based catalysts // Jose Guadalupe Santiesteban.
Author:	Santiesteban, Jose Guadalupe,
Description:	1 electronic resource (272 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 51-06, Section: B.
Contained By:	Dissertations Abstracts International51-06B.
Subject:	Chemistry. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=8921639
ISBN:	9798207813530

Alcohol synthesis from carbon-monoxide and hydrogen over molybdenum-disulfide based catalysts /
Santiesteban, Jose Guadalupe,

Alcohol synthesis from carbon-monoxide and hydrogen over molybdenum-disulfide based catalysts /Jose Guadalupe Santiesteban. - 1 electronic resource (272 pages)

Source: Dissertations Abstracts International, Volume: 51-06, Section: B.

The synthesis of linear C$\\sb1$-C$\\sb4$ alcohols from synthesis gas (CO + H$\\sb2$) over alkali-promoted MoS$\\sb2$-based catalysts has been studied. A large doping level of alkali was essential for the formation of alcohols rather than hydrocarbons over these catalysts. The indispensable presence of the alkali salt promoter for alcohol synthesis was due to the bifunctionality of the catalyst in which the alkali activates CO and MoS$\\sb2$ activates H$\\sb2$. Injection of $\\sp{13}$C-labeled CH$\\sb3$OH into the synthesis gas stream over alkali-promoted MoS$\\sb2$-based catalysts and analysis by $\\sp{13}$C NMR spectroscopy of the condensable products, accompanied by mass spectrometric analysis of light gaseous products, demonstrated that the alcohol chain growth occurred via a classical CO insertion mechanism, and that methane is a secondary product that is formed from an alkyl moiety generated from a C$\\sb1$-oxygenated precursor. The addition of cobalt to the alkali-doped MoS$\\sb2$ catalyst greatly enhanced the rate of the C$\\sb1$ $\o$ C$\\sb2$ growth step so that ethanol became the dominant product. The alkali-doped MoS$\\sb2$ catalysts prior to and after attaining their working state were fully characterized by XPS, XRD, STEM, and surface area measurements. Electron microscopy results indicated that the MoS$\\sb2$ portion of the catalyst consists of a semicrystalline hexagonal structure with regular lattice spacings (d(002) = 6.15 A) that indicate no intercalation of the alkali. The cesium salt in the best catalysts (10-20 wt% CsOOCH) is distributed as $\\approx$200 A diameter particles and also as a fine surface dispersion. The cesium particle agglomeration results from the low surface energy of MoS$\\sb2$ and is the cause of the large levels of cesium required for the optimal functioning of the catalyst. Pretreatment (400$\\sp\\circ$C, 2% H$\\sb2$/N$\\sb2$, 1 h) of the catalysts induces not only reduction of surface species such as Mo(VI) and SO$\\sb4\\sp{2-}$ detected on the fresh catalysts, but also dispersion of the cesium on the MoS$\\sb2$ surface. The oxidation states of S and Mo in the tested catalysts correspond to those of MoS$\\sb2$, i.e. Mo(IV) and S$\\sp{2-}$. XPS intensity equations were derived from geometrical models of the catalyst surface to determine the degree of dispersion and/or segregation of Cs on the MoS$\\sb2$ surface.

English

ISBN: 9798207813530Subjects--Topical Terms:

516420
Chemistry.
Subjects--Index Terms:

Molybdenum silicide

Alcohol synthesis from carbon-monoxide and hydrogen over molybdenum-disulfide based catalysts /
LDR:03665nmm a22003973i 4500 001 2396254
005 20250522083218.5
006 m o d
007 cr|nu||||||||
008 251215s1989 miu||||||m |||||||eng d
020 $a 9798207813530
035 $a (MiAaPQD)AAI8921639
035 $a AAI8921639
040 $a MiAaPQD $b eng $c MiAaPQD $e rda
100 1 $a Santiesteban, Jose Guadalupe, $e author. $3 3765925
245 1 0 $a Alcohol synthesis from carbon-monoxide and hydrogen over molybdenum-disulfide based catalysts / $c Jose Guadalupe Santiesteban.
264 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 1989
300 $a 1 electronic resource (272 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 51-06, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
502 $b Ph.D. $c Lehigh University $d 1989.
520 $a The synthesis of linear C$\\sb1$-C$\\sb4$ alcohols from synthesis gas (CO + H$\\sb2$) over alkali-promoted MoS$\\sb2$-based catalysts has been studied. A large doping level of alkali was essential for the formation of alcohols rather than hydrocarbons over these catalysts. The indispensable presence of the alkali salt promoter for alcohol synthesis was due to the bifunctionality of the catalyst in which the alkali activates CO and MoS$\\sb2$ activates H$\\sb2$. Injection of $\\sp{13}$C-labeled CH$\\sb3$OH into the synthesis gas stream over alkali-promoted MoS$\\sb2$-based catalysts and analysis by $\\sp{13}$C NMR spectroscopy of the condensable products, accompanied by mass spectrometric analysis of light gaseous products, demonstrated that the alcohol chain growth occurred via a classical CO insertion mechanism, and that methane is a secondary product that is formed from an alkyl moiety generated from a C$\\sb1$-oxygenated precursor. The addition of cobalt to the alkali-doped MoS$\\sb2$ catalyst greatly enhanced the rate of the C$\\sb1$ $\o$ C$\\sb2$ growth step so that ethanol became the dominant product. The alkali-doped MoS$\\sb2$ catalysts prior to and after attaining their working state were fully characterized by XPS, XRD, STEM, and surface area measurements. Electron microscopy results indicated that the MoS$\\sb2$ portion of the catalyst consists of a semicrystalline hexagonal structure with regular lattice spacings (d(002) = 6.15 A) that indicate no intercalation of the alkali. The cesium salt in the best catalysts (10-20 wt% CsOOCH) is distributed as $\\approx$200 A diameter particles and also as a fine surface dispersion. The cesium particle agglomeration results from the low surface energy of MoS$\\sb2$ and is the cause of the large levels of cesium required for the optimal functioning of the catalyst. Pretreatment (400$\\sp\\circ$C, 2% H$\\sb2$/N$\\sb2$, 1 h) of the catalysts induces not only reduction of surface species such as Mo(VI) and SO$\\sb4\\sp{2-}$ detected on the fresh catalysts, but also dispersion of the cesium on the MoS$\\sb2$ surface. The oxidation states of S and Mo in the tested catalysts correspond to those of MoS$\\sb2$, i.e. Mo(IV) and S$\\sp{2-}$. XPS intensity equations were derived from geometrical models of the catalyst surface to determine the degree of dispersion and/or segregation of Cs on the MoS$\\sb2$ surface.
546 $a English
590 $a School code: 0105
650 4 $a Chemistry. $3 516420
650 4 $a Mental health. $3 534751
650 4 $a Mathematics. $3 515831
650 4 $a Radiology. $3 894545
650 4 $a Physical chemistry. $3 1981412
650 4 $a Medical imaging. $3 3172799
653 $a Molybdenum silicide
690 $a 0494
690 $a 0347
690 $a 0405
690 $a 0574
690 $a 0485
710 2 $a Lehigh University. $e degree granting institution. $3 3765926
773 0 $t Dissertations Abstracts International $g 51-06B.
790 $a 0105
791 $a Ph.D.
792 $a 1989
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=8921639