The demand for mixed alcohols has grown since ether compounds were banned as gasoline octane improvers in North America. Molybdenum-based catalysts in sulfide form are an attractive catalyst system for the conversion of synthesis gas to alcohols, due to their excellent resistance to sulfur poisoning and high activity for the water-gas shift reaction. The higher alcohols activity over these catalysts is low, due to the formation of hydrocarbons and CO2. Although a number of catalysts have been developed for this purpose, not any are used commercially at this time. The main objective of this Ph.D. research is to develop a catalyst system that is capable of selectively producing higher alcohols, particularly ethyl alcohols from synthesis gas. In the present series of studies, the investigation of an alkali-promoted trimetallic Co-Rh-Mo catalyst system has led to improvements in product stream composition. The effect of different loadings of active metal (Mo), alkali (K) promoter, and metal promoters (Co and Rh) on higher alcohol synthesis from synthesis gas were investigated using commercially available multi-walled carbon nanotubes (MWCNTs) as the catalyst support. The role of support on higher alcohols synthesis was also studied using different supports, such as ã-Al2O3, activated carbons with different textural characteristics, and MWCNTs. The catalysts were prepared using the incipient wetness impregnation method and extensively characterized in both oxide and sulfide phases using different techniques. Transmission electron microscopy (TEM) results revealed that the metal particles were uniformly distributed inside and outside of the carbon nanotubes, and that metal dispersions were higher on the alkali-promoted trimetallic catalyst supported on MWCNTs. The existence of promoted and un-promoted MoS2 sites was confirmed by diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) studies of adsorbed CO over sulfided catalysts. Temperature programmed reduction (TPR) tests showed that the addition of metal promoters improved the reduction behaviour of the catalysts. XRD patterns showed that alkali-promoted catalysts were less crystalline compared to that of the catalyst not promoted with K. The formation of Co (Rh)-Mo-S species was evident in the XANES spectra of bimetallic and trimetallic alkali-promoted MoS2 catalysts. The activity and selectivity of the catalysts were assessed in a fixed-bed micro-reactor using temperature, pressure, and gas hourly space velocity in the ranges of 275 to 350°C, 800 to 1400 psig (5.529.65 Mpa), and 2.4 to 4.2 m3 (STP)/(kg of cat.)/h, respectively. The Ni-promoted catalyst showed higher activity towards the formation of hydrocarbons over that of alcohols. The total alcohols space time yield (STY) and higher alcohols selectivities are significantly higher over the activated carbon-supported catalysts compared to those supported on alumina. With increased content of K, the formation of alcohols increased and hydrocarbons formation rate was suppressed. The total alcohols STY increased with increased Co content over the Co-promoted MoS2-K/MWCNTs catalysts, whereas, the maximum ethyl alcohol and higher alcohols selectivities were observed on the catalyst promoted with 4.5 wt % Co. Over the Rh-promoted MoS2-K/MWCNTs catalysts, the maximum total alcohol yield, ethanol selectivity, and higher alcohols selectivity were observed on the catalyst with 1.5 wt % Rh. The MWCNT-supported alkali-promoted trimetallic catalyst with 9 wt % K, 4.5 wt % Co, 1.5 wt % Rh, and 15 wt % Mo showed the maximum higher alcohols STY and selectivity compared to other catalysts investigated. The textural properties of the support, such as average pore diameter, pore volume and surface area, could significantly influence the extent of reduction, morphology, adsorption and has direct influence on the synthesis of mixed alcohols from synthesis gas. The optimum higher alcohols STY and selectivity were obtained over the Co-Rh-Mo-K/MWCNT catalyst at 330°C, 1320 psi (9.1 Mpa), 3.8 m3 (STP)/(kg of cat./h) using a H2 to CO molar ratio value of 1.25. To predict the reaction rate for higher alcohols synthesis, the power law model was used for the reaction between CO and H2 on the catalyst surface and the data of this study are well fitted by the model. The activation energies of ethanol and higher alcohols obtained over Co-Rh-Mo-K/MWCNTs were low compared to those values reported in the literature. The sulfided alkali-promoted trimetallic Co-Rh-Mo catalyst supported on MWCNTs was stable over a period of 720 h of continuous reaction.

The demand for mixed alcohols has grown since ether compounds were banned as gasoline octane improvers in North America. Molybdenum-based catalysts in sulfide form are an attractive catalyst system for the conversion of synthesis gas to alcohols, due to their excellent resistance to sulfur poisoning and high activity for the water-gas shift reaction. The higher alcohols activity over these catalysts is low, due to the formation of hydrocarbons and CO2. Although a number of catalysts have been developed for this purpose, not any are used commercially at this time. The main objective of this Ph.D. research is to develop a catalyst system that is capable of selectively producing higher alcohols, particularly ethyl alcohols from synthesis gas. In the present series of studies, the investigation of an alkali-promoted trimetallic Co-Rh-Mo catalyst system has led to improvements in product stream composition. The effect of different loadings of active metal (Mo), alkali (K) promoter, and metal promoters (Co and Rh) on higher alcohol synthesis from synthesis gas were investigated using commercially available multi-walled carbon nanotubes (MWCNTs) as the catalyst support. The role of support on higher alcohols synthesis was also studied using different supports, such as ã-Al2O3, activated carbons with different textural characteristics, and MWCNTs. The catalysts were prepared using the incipient wetness impregnation method and extensively characterized in both oxide and sulfide phases using different techniques. Transmission electron microscopy (TEM) results revealed that the metal particles were uniformly distributed inside and outside of the carbon nanotubes, and that metal dispersions were higher on the alkali-promoted trimetallic catalyst supported on MWCNTs. The existence of promoted and un-promoted MoS2 sites was confirmed by diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) studies of adsorbed CO over sulfided catalysts. Temperature programmed reduction (TPR) tests showed that the addition of metal promoters improved the reduction behaviour of the catalysts. XRD patterns showed that alkali-promoted catalysts were less crystalline compared to that of the catalyst not promoted with K. The formation of Co (Rh)-Mo-S species was evident in the XANES spectra of bimetallic and trimetallic alkali-promoted MoS2 catalysts. The activity and selectivity of the catalysts were assessed in a fixed-bed micro-reactor using temperature, pressure, and gas hourly space velocity in the ranges of 275 to 350°C, 800 to 1400 psig (5.529.65 Mpa), and 2.4 to 4.2 m3 (STP)/(kg of cat.)/h, respectively. The Ni-promoted catalyst showed higher activity towards the formation of hydrocarbons over that of alcohols. The total alcohols space time yield (STY) and higher alcohols selectivities are significantly higher over the activated carbon-supported catalysts compared to those supported on alumina. With increased content of K, the formation of alcohols increased and hydrocarbons formation rate was suppressed. The total alcohols STY increased with increased Co content over the Co-promoted MoS2-K/MWCNTs catalysts, whereas, the maximum ethyl alcohol and higher alcohols selectivities were observed on the catalyst promoted with 4.5 wt % Co. Over the Rh-promoted MoS2-K/MWCNTs catalysts, the maximum total alcohol yield, ethanol selectivity, and higher alcohols selectivity were observed on the catalyst with 1.5 wt % Rh. The MWCNT-supported alkali-promoted trimetallic catalyst with 9 wt % K, 4.5 wt % Co, 1.5 wt % Rh, and 15 wt % Mo showed the maximum higher alcohols STY and selectivity compared to other catalysts investigated. The textural properties of the support, such as average pore diameter, pore volume and surface area, could significantly influence the extent of reduction, morphology, adsorption and has direct influence on the synthesis of mixed alcohols from synthesis gas. The optimum higher alcohols STY and selectivity were obtained over the Co-Rh-Mo-K/MWCNT catalyst at 330°C, 1320 psi (9.1 Mpa), 3.8 m3 (STP)/(kg of cat./h) using a H2 to CO molar ratio value of 1.25. To predict the reaction rate for higher alcohols synthesis, the power law model was used for the reaction between CO and H2 on the catalyst surface and the data of this study are well fitted by the model. The activation energies of ethanol and higher alcohols obtained over Co-Rh-Mo-K/MWCNTs were low compared to those values reported in the literature. The sulfided alkali-promoted trimetallic Co-Rh-Mo catalyst supported on MWCNTs was stable over a period of 720 h of continuous reaction.

Chiral 1,2-amino alcohols were synthesized via newly developed &ldquo / intramolecular unsaturation transfer&rdquo / using cyclohexanone, propargyl bromide, and various chiral amino alcohols as starting components. These amino alcohols can be potential chiral ligands for many asymmetric transformation reactions. Therefore, their effectiveness as chiral ligands in diethylzinc addition to benzaldehyde and N-diphenylphosphinoyl imines were tested. Various parameters including temperature, solvent, ligand amount etc. were screened for the synthesized chiral ligands. In diethylzinc addition to benzaldehyde high enantioselectivity could not be obtained. When N-diphenylphosphinoyl imines were used as substrate good ee values up to 80% were achieved.

<p>The first part of this thesis describes a synthetic strategythat provides all eight possible isomers of a given vic-aminoalcohol starting from vinylepoxides. The value of a generalroute is evident, as several isomers are needed ininvestigations of structure-activity relationships forpharmacologically active derivatives, and for optimizing theperformance of chiral ligands containing the amino alcoholmoiety.</p><p>Vinylepoxides, obtained in high enantiomeric excess, werering-opened both with inversion and retention ofstereochemistry, delivering two diastereomeric amino alcoholswith high regio- and stereoselectivity. Via ring-closure toaziridines and subsequent regioselective ring-opening withsuitable oxygen nucleophiles, the two remaining amino alcoholswere selectively achieved.</p><p>Within this study, two efficient protocols for theregioselective and stereospecific aminolysis of vinylepoxideshave been presented. Comparedto previous methods, theseprocedures use milder reaction conditions, shorter reactiontimes, generally give higher yields and are applicable to alarger set of substrates. Furthermore, the ring-closure ofvic-amino alcohols to the corresponding N-H vinylaziridines hasbeen investigated. Three routes have been found useful, whichone is preferred depends on substrate and scale.</p><p>In the second part of the thesis, the synthetic strategy isapplied on the synthesis of Sphingosine and its regio- andstereoisomers. Moreover, a rapid way of determining relativeconfiguration of vic-amino alcohols is described, which shouldbe of substantial use when amino alcohols are formed bydiastereoselective reactions.</p><p>amino alcohols, vinylepoxides, vinylaziridines, oxazolines,oxazolidinones, ring-opening, regioselective,diastereoselective, sphingosine, configuration, NMRspectroscopy.</p>

Sol-gel capillary microextraction (CME) is a new direction in solvent-free extraction and preconcentration of trace analytes. CME presents significant interest in environmental, pharmaceutical, petrochemical, biomedical, agricultural, food, flavor, and a host of other important areas. Sol-gel CME utilizes advanced material properties of organic-inorganic hybrid sol-gel polymers to perform efficient extraction and enrichment of target analytes from a variety of matrices. In this dissertation, two novel sol-gel coatings were developed for CME: (a) sol-gel benzyl-terminated dendrimer coating, and (b) sol-gel polytetrahydrofuran (poly-THF) coating. A detailed investigation was conducted to evaluate the performance of the newly developed sol-gel coatings in solvent-free extraction of a wide range of polar and nonpolar analytes. Sol-gel chemistry was used to chemically immobilize dendrimer- and poly-THF-based hybrid organic-inorganic coatings on fused silica capillary inner surface. The sol-gel coatings were created using a coating solution containing a sol-gel active organic component (dendrimer or poly-THF), a sol-gel precursor (methyltrimethoxysilane, MTMOS), a sol-gel catalyst (trifluoroacetic acid, TFA, 5% water) and a deactivating reagent (hexamethyldisilazane, HMDS). Sol-gel reactions were conducted inside a hydrothermally treated fused silica capillary for 60 min. A wall-bonded sol-gel coating was formed via condensation of silanol groups residing on the capillary inner surface with those on the sol-gel network fragments evolving in close vicinity of the capillary walls. Due to the strong chemical bonding with capillary inner walls, these sol-gel coatings showed excellent thermal and solvent stability in CME in hyphenation with gas chromatography (GC).

Darbo tikslas - įvertinti aukštesniųjų alkoholių ir kitų fuzelio junginių bei fizikinių cheminių rodiklių kitimo tendencijas skirtingų gamintojų aluje. Darbe panaudoti metodai : Ca ir Zn tiriamuosiuose mėginiuose buvo nustatyti taikant atominės absorbcijos liepsnos spektrometrinį metodą. pH nustatytas pH-metru „Mettler Toledo 220”, pagal įrengimo gamintojo nurodymus, vadovaujantis prietaiso instrukcija.Sausosios medžiagos, alkoholio kiekis masės bei tūrio procentais nustatytas pagal LST 1572:2004 Alus. Etilo alkoholio koncentracijos, tikrojo ir pradinio ekstrakto nustatymas. Vikinaliniai diketonai ir kartumas nustatyti Europos aludarių konvencijos oficialiame leidinyje pateiktais metodais: VDK. Europos aludarių knvencijos leidinys, Analytica EBC 9.2.4.1 Vikinaliniai diketonai aluje. Spektroftometrinis metodas, 2000 m. 5-tas leidimas. Kartumas nustatytas metodu, pateiktu Europos aludarių konvencijos leidinyje, Analytica EBC 9.8 Alaus kartumas, 1997 m. 5-tas leidimas.Taip pat buvo atlikta matematinė statistinė duomenų analizė. Aukštesniųjų alkoholių nustatymas atliktas dujų chromatografijos metodu. Išvados. Aukštesniųjų alkoholių (acetaldehido, etilacetato, metanolio, propanolio, izobutanolio, izoamiloalkoholio) kiekiai aluje parodė, kad ryškesnėmis skonio bei aromato savybėmis pasižymi elio alus, o lager tipo aluje šių junginių kiekis mažesnis. Aukštesniųjų alkoholių bei kitų fuzelio junginių kiekis tirtame aluje kito priklausomai nuo alaus rūšies. Skirtingų rūšių alaus... [toliau žr. visą tekstą] / Tasks of work: To identify the higher alcohols and other fusel oil compounds in beer samples; Rate higher alcohols and other compounds changing tendencies in lager-type beers and ale-type beers; to determine the differences of physico-chemical parameters of different beer producers; to perform a comparative evaluation of the test samples safety. The methods used in experiment: content of the Ca(calcium) and Zn (zink) was investigated by atomic absorption flame spectrometry method; pH – with pH meter "Mettler Toledo 220, according to the manufacturer's instruction. Original extract, the amount of alcohol was determined in accordance with LST Beer 1572:2004. Ethyl alcohol concentration, real and original extract determination. Vikinal dicetones and bitterness set the Brewers Convention, Official Journal of the methods: EBC. Journal of European Brewers Convencion, Analytica EBC 9.2.4.1 Vikinal diketones in beer. Spektrofotometrical method, 2000. 5th edition. Set of bitterness method given the Journal Brewers Convention Journal, Analytica EBC 9.8 beer bitterness, 1997. 5 th edition. Higher alcohols and other fusel oil compounds was determine by gas chromatography method. Results: The higher alcohols in beer showed that the highest intensivity of flavor and aroma is in Ale- type of beer, and in lager-type beer these compounds content was found lower. Higher alcohols and other fusel oil compounds were depended on beer type. Physical chemical characteristics of beer were different... [to full text]

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 131-132). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 131-132). Also available on the Internet.

Thesis (Ph.D. in Biochemistry, Biomolecular Structure Program) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 135-146). Online version available via ProQuest Digital Dissertations.

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