Higher alcohols synthesized via CO hydrogenation reactions have been a topic of intense study both in industry and academia for over thirty years. A variety of transition metals and promoters have been used in catalysts for this reaction. MoS₂, in particular, is popular due to its low cost, resistance to sulfur poisoning, and ability to selectively produce higher alcohols over hydrocarbons. The bulk material has a rich history in hydrodesulfurization reactions (HDS), and as such, a great deal is known about the material's structure and reactivity. However, even with this deep body of knowledge about the bulk catalyst, no one has yet been able to implement an industrially viable variation of the catalyst to make higher alcohols. Supported MoS₂ has also been studied for the same purpose. Generally, supports are employed to improve catalyst productivity per gram of Mo by dispersing the metal and increasing the amount of catalytically active surface area. However, product selectivity may also be influenced by chemical properties of the supports. Specifically, gamma alumina has been shown to raise hydrocarbon formation due to intrinsic surface acidity. The effects of basic supports are reported on the CO hydrogenation reaction are reported. K promoted Mo is supported on two basic materials - commercial sepiolite (Si₁₂Mg₈O₃₀(OH)₄) and hydrotalcite-derived Mg/Al mixed metal oxides (MMO). The catalysts are reacted with syngas, and the resultant product selectivities are compared at isoconversions. Activated carbon supported Mo and bulk MoS₂ are also used as controls. It is shown that MMO provides a unique promotional effect by suppressing methanol formation and favoring higher alcohols. The specific role of MMO in the reaction is investigated by combining it in three different ways with Mo. 1) MMO is impregnated with Mo in the classic fashion. 2) Bare MMO or MMO/K is placed as a secondary bed downstream of the principle catalyst (K promoted Mo supported on MMO). 3) Bare MMO or MMO/K is mixed with the principle catalyst to make a homogeneous bed. It is shown that MMO by itself is somewhat inert in the reaction while MMO/K has some higher alcohol forming activity. More importantly however, it is shown that the MMO:Mo ratio has far greater effects on selectivity than the morphology of MoS₂. There is evidence however that MoS₂ morphology can affect activity. It is hypothesized that a greater degree of stacking in MoS₂ domains leads to reduced activity. The existence of coupling and homologation pathways are investigated by feeding methanol or ethanol into the syngas as it enters the catalyst bed. By comparing changes in the productivity of different higher alcohols with the liquid feed, it is shown that an MMO supported catalyst is much more reactive with methanol and somewhat more reactive with ethanol than its bulk MoS₂ counterpart. It is shown that for both the bulk and supported catalysts, the addition of a Cx alcohol results in the largest increase in Cx+1 products, suggesting that alcohol homologation is in fact the most favored route to higher alcohols by these materials.

The present thesis concerns catalytic conversion of syngas (H2+ CO) into a blend of methanol and higher alcohols, an attractive way of producing fuels and chemicals. This route has the potential to reduce the oil dependence in the transport sector and, with the use of biomass for the syngas generation, produce CO2-neutral fuels. Alkali promoted MoS2-based catalysts show a high selectivity to higher alcohols, while at the same time being coke resistant, sulfur tolerant and displaying high water-gas shift activity. This makes this type of catalyst especially suitable for being used with syngas derived from biomass or coal which typically has a low H2/CO-ratio. This thesis discusses various important aspects of higher alcohol synthesis using MoS2-based catalysts and is a summary of four scientific papers. The first part of the thesis gives an introduction to how syngas can be produced and converted into different fuels and chemicals. It is followed by an overview of higher alcohol synthesis and a description of MoS2-based catalysts. The topic alcohol for use in internal combustion engines ends the first part of the thesis. In the second part, the experimental part, the preparation of the MoS2-based catalysts and the characterization of them are handled. After describing the high-pressure alcohol reactor setup, the development of an on-line gas chromatographic system for higher alcohol synthesis with MoS2 catalysts is covered (Paper I). This method makes activity and selectivity studies of higher alcohol synthesis catalysts more accurate and detailed but also faster and easier. Virtually all products are very well separated and the established carbon material balance over the reactor closed well under all tested conditions. The method of trace level sulfur analysis is additionally described. Then the effect of operating conditions, space velocity and temperature on product distribution is highlighted (Paper II). It is shown that product selectivity is closely correlated with the CO conversion level and why it is difficult to combine both a high single pass conversion and high alcohol selectivity over this catalyst type. Correlations between formed products and formation pathways are additionally described and discussed. The CO2 pressure in the reactor increases as the CO conversion increases, however, CO2 influence on formation rates and product distribution is to a great extent unclear. By using a CO2-containing syngas feed the effect of CO2 was studied (Paper III). An often emphasized asset of MoS2-based catalysts is their sulfur tolerance. However, the use of sulfur-containing feed and/or catalyst potentially can lead to incorporation of unwanted organic sulfur compounds in the product. The last topic in this thesis covers the sulfur compounds produced and how their quantity is changed when the feed syngas contains H2S (Paper IV). The effect on catalyst activity and selectivity in the presence of H2S in the feed is also covered. / <p>QC 20150115</p>

A study of solid base catalysis was conducted in three main categories, namely condensation reactions of primary alcohols, alkylation reactions of dihydroxybenzene and hydrogenation reactions of phenol. Ethanol was converted into 1-butanol over alkali earth metal oxides and modified MgO catalysts (1-20 % yield). The MgO catalyst exhibits the highest reaction activity and 1-butanol selectivity amongst the catalysts studied. Reaction of various possible intermediates (acetaldehyde, crotonaldehyde, crotylalcohol, butanal) and ethanol over MgO (1 bar, 450 oC) revealed that the dimerisation reaction does not proceed primarily through the aldol condensation reaction. The reaction is proposed to proceed through a mechanism, previously proposed by Yang and Meng, in which a C-H bond in the -position in ethanol is activated by the basic metal oxide, and condenses with another molecule of ethanol, by dehydration to form 1-butanol. iv A self-condensation reaction of propanol was carried out at atmospheric pressure over MgO as catalyst. The reaction gave 2-methylpentanol and propionaldehyde as the major products. The introduction of hydrogen before and during the reaction enhanced the catalyst selectivity to 2- methylpentanol. The effect of possible reaction intermediates on the catalyst selectivity and the mechanism of the reaction were investigated over MgO and indicated the important role of hydrogen transfer in the reaction. The highest selectivity (69 %) was achieved in the presence of hydrogen at 450 oC with propanol conversion of 24 %. Condensation reactions of ethanol with butanol or propanol to higher alcohols were carried out at atmospheric pressure over various solid-base catalysts. The ability of ethanol to be activated at either the CH2 or CH3 units played a significant role in the formation of a wide range of long chain alcohols. The major products observed during the reaction between ethanol and butanol were 2-ethylbutanol, 1-hexanol and to a lesser extent 2-ethyhexanol. The main products in the reaction of ethanol and propanol were 2-methylbutanol, 1-pentanol and butanol. Trace amounts of 2- methylpentanol were also observed. The vapour phase alkylation of catechol over supported cesium catalysts gave good selectivity to guaiacol formation. The TPD studies of the catalysts used indicated that the results can be correlated with the presence of weak basic sites on the catalyst. The gas phase selective hydrogenation of phenol to cyclohexanone was investigated over palladium supported catalysts in order to clarify the influence of the support on products distribution. High selectivities towards cyclohexanone (about 86 %) were observed on palladium supported on high surface area titanium oxide supports. On the basis of the TPD studies, it has been suggested that the basic properties of the support strongly influence the adsorption-desorption of phenol and products, and are therefore responsible for the selectivity towards the reaction products

Climate change is one of the biggest global threats of the 21st century. Fossil fuels constitute by far the most important energy source for transportation and the different governments are starting to take action to promote the use of cleaner fuels. Biomass-derived fuels are a promising alternative for diversifying fuel sources, reducing fossil fuel dependency and abating greenhouse gas emissions. The research interest has quickly shifted from first-generation biofuels, obtained from food commodities, to second-generation biofuels, produced from non-food resources. The subject of this PhD thesis is the production of second-generation biofuels via thermochemical conversion: biomass is first gasified to synthesis gas, a mixture of mainly H2 and CO; synthesis gas can then be catalytically converted to different fuels. This work summarizes six publications, which are focused on the synthesis gas conversion step. Two processes are principally examined in this summary. The first part of the PhD thesis is devoted to the synthesis of ethanol and higher alcohols, which can be used as fuel or fuel additives. The microemulsion technique is applied in the synthesis of molybdenum-based catalysts, achieving a yield enhancement. Methanol cofeeding is also studied as a way of boosting the production of longer alcohols, but a negative effect is obtained: the main outcome of methanol addition is an increase in methane production. The second part of the PhD thesis addresses wax hydroconversion, an essential upgrading step in the production of middle-distillate fuels via Fischer-Tropsch. Bifunctional catalysts consisting of noble metals supported on silica-alumina are considered. The deactivation of a platinum-based catalyst is investigated, sintering and coking being the main causes of decay. A comparison of platinum and palladium as catalyst metal function is also carried out, obtaining a fairly different catalytic performance of the materials in terms of conversion and selectivity, very likely due to dissimilar hydrogenation power of the metals. Finally, a kinetic model based on the Langmuir-Hinshelwood-Hougen-Watson formalism is proposed to describe the hydroconversion reactions, attaining a good fitting of the experimental data. / Klimatförändringarna är ett av de största globala hoten under det tjugoförsta århundradet. Fossila bränslen utgör den helt dominerande energikällan för transporter och många länder börjar stödja användning av renare bränslen. Bränslen baserade på biomassa är ett lovande alternativ för att diversifiera råvarorna, reducera beroendet av fossila råvaror och undvika växthusgaser. Forskningsintresset har snabbt skiftat från första generationens biobränslen som erhölls från mat-råvaror till andra generationens biobränslen producerade från icke ätbara-råvaror. Ämnet för denna doktorsavhandling är produktion av andra generationens biobränslen via termokemisk omvandling. Biomassa förgasas först till syntesgas, en blandning av i huvudsak vätgas och kolmoxid; syntesgasen kan sedan katalytiskt omvandlas till olika bränslen. Detta arbete sammanfattar sex publikationer som fokuserar på steget för syntesgasomvandling. Två processer är i huvudsak undersökta i denna sammanfattning. Den första delen av doktorsavhandlingen ägnas åt syntes av etanol och högre alkoholer som kan användas som bränsle eller bränsletillsatser. Mikroemulsionstekniken har använts vid framställningen av molybden-baserade katalysatorer, vilket gav en höjning av utbytet. Tillsatsen av metanol har också studerats som ett sätt att försöka få en högre koncentration av högre alkoholer, men en negativ effekt erhölls: huvudeffekten av metanoltillsatsen är en ökad metanproduktion. Den andra delen av doktorsavhandlingen handlar om vätebehandling av vaxer som ett viktigt upparbetningssteg vid framställning av mellandestillat från Fischer-Tropsch processen. Bifunktionella katalysatorer som består av ädelmetaller deponerade på silica-alumina valdes. Deaktiveringen av en platinabaserad katalysator undersöktes. Sintring och koksning var huvudorsakerna till deaktiveringen. En jämförelse mellan platina och palladium som funktionella metaller genomfördes också med resultatet att det var en ganska stor skillnad mellan materialens katalytiska egenskaper vilket gav olika omsättning och selektivitet, mycket sannolikt beroende på olika reaktionsmönster hos metallerna vid vätebehandling. Slutligen föreslås en kinetisk modell baserad på en Langmuir-Hinshelwood-Hougen-Watson modell för att beskriva reaktionerna vid vätebehandling. Denna modell ger en god anpassning till experimentella data. / El cambio climático es una de las mayores amenazas del siglo XXI. Los combustibles fósiles constituyen actualmente la fuente de energía más importante para el transporte, por lo que los diferentes gobiernos están empezando a tomar medidas para promover el uso de combustibles más limpios. Los combustibles derivados de biomasa son una alternativa prometedora para diversificar las fuentes de energía, reducir la dependencia de los combustibles fósiles y disminuir las emisiones de efecto invernadero. Los esfuerzos de los investigadores se han dirigido en los últimos años a los biocombustibles de segunda generación, producidos a partir de recursos no alimenticios. El tema de esta tesis de doctorado es la producción de biocombustibles de segunda generación mediante conversión termoquímica: en primer lugar, la biomasa se gasifica y convierte en gas de síntesis, una mezcla formada mayoritariamente por hidrógeno y monóxido de carbono; a continuación, el gas de síntesis puede transformarse en diversos biocombustibles. Este trabajo resume seis publicaciones, centradas en la etapa de conversión del gas de síntesis. Dos procesos se estudian con mayor detalle. En la primera parte de la tesis se investiga la producción de etanol y alcoholes largos, que pueden ser usados como combustible o como aditivos para combustible. La técnica de microemulsión se aplica en la síntesis de catalizadores basados en molibdeno, consiguiendo un incremento del rendimiento. Además, se introduce metanol en el sistema de reacción para intentar aumentar la producción de alcoholes más largos, pero los efectos obtenidos son negativos: la principal consecuencia es el incremento de la producción de metano. La segunda parte de la tesis estudia la hidroconversión de cera, una etapa esencial en la producción de destilados medios mediante Fischer-Tropsch. Los catalizadores estudiados son bifuncionales y consisten en metales nobles soportados en sílice-alúmina. La desactivación de un catalizador de platino se investiga, siendo la sinterización y la coquización las principales causas del problema. El uso de platino y paladio como componente metálico se compara, obteniendo resultados catalíticos bastante diferentes, tanto en conversión como en selectividad, probablemente debido a su diferente capacidad de hidrogenación. Finalmente, se propone un modelo cinético, basado en el formalismo de Langmuir-Hinshelwood-Hougen-Watson, que consigue un ajuste satisfactorio de los datos experimentales. / <p>QC 20160308</p>

The thermochemical process converts almost any kind of biomass to a desired final product, i.e. gaseous or liquid transportation fuels and chemicals. The transportation fuels obtained in this way are renewable biofuels, which are alternatives to fossil fuels. During the last few years, thermochemical plants for the production of bioethanol have been launched and another is under construction. A total of about 290 million liters of ethanol are expected to be processed per year, mostly using municipal solid waste. Considerable efforts have been made in order to find a more selective catalyst for the conversion of biomass-derived syngas to ethanol. The thesis is the summary of five publications. The first two publications (Papers I and II) review the state of the art of ethanol and higher alcohols production from biomass, as well as the current status of synthetic fuels production by other processes such as the Fischer-Tropsch synthesis. Paper III analyses the catalytic performance of a mesoporous Rh/MCM-41 (MCM-41 is a hexagonal mesoporous silica) in the synthesis of ethanol which is compared to a typical Rh/SiO2 catalyst. Exhaustive catalytic testing including the addition of water vapor and modifying the hydrogen partial pressure in the syngas feed-stream which, in addition to the catalyst characterization (XRD, BET, XPS, chemisorption, TEM and TPR) before and after the catalytic testing, have allowed concluding that some water vapor can be concentrated in the pores of the Rh/MCM-41 catalyst. The concentration of water-vapor promotes the occurrence of the water gas shift reaction, which in turn induces some secondary reactions that change the product distribution, as compared to results obtained from the typical Rh/SiO2 catalyst. These results have been verified in a wide range of syngas conversion levels (1-68 %) and for different catalyst activation procedures (catalyst reduction at 200 °C, 500 °C and no-reduction) as shown in Paper IV. Finally, similar insights about the use of mesoporous catalyst have been found over a Cu/MCM-41 catalyst, shown in Paper V. Also in Paper V, the effect of metal promoters (Fe and K) has been studied; a noticeable increase of ethanol reaction rate was found over Cu-Fe-K/MCM-41 catalyst as compared to Cu/MCM-41. / <p>QC 20161125</p>

Le CO2 est une source de carbone propre pour les réactions chimiques, nombreux chercheurs ont étudié l'utilisation du CO2. Les alcools supérieurs sont des additifs de carburant propres. La synthèse des alcools supérieurs à partir de l'hydrogénation du CO a également été étudiée par de nombreux chercheurs, mais il existe peu de littératures sur la synthèse des alcools supérieurs à partir de l'hydrogénation du CO2, qui est une réaction complexe et difficile. Les catalyseurs utilisés pour la synthèse des alcools supérieurs nécessitent au moins deux phases actives et une bonne synergie. Dans notre étude, nous avons étudié les catalyseurs spinelle basés sur Co. Cu. Fe et l'effet des supports (CNTs et TUD-1) et celui des promoteurs (K, Na, Cs) à la réaction de HAS. Nous avons trouvé que le catalyseur CuFe-précurseur-800 est favorable pour la synthèse d'hydrocarbures en C2+ et d'alcools supérieurs. Dans l'hydrogénation du CO2, Co agit comme catalyseur de méthanisation plutôt que comme catalyseur FT, en raison du mécanisme de réaction différent entre l'hydrogénation du CO et celle du CO2. Afin d'inhiber la formation d'hydrocarbures de quantités importante, il est préférable de choisir des catalyseurs sans Co dans la réaction d'hydrogénation du CO2. En comparant les fonctions des CNT et du TUD-1, nous avons constaté que le CNT est un support parfait pour la synthèse de produits à longue chaîne (alcools supérieurs et hydrocarbures C2+). Le support TUD-1 est plus adapté à la synthèse de produits à un seul carbone (méthane et méthanol) .L'addition d'alcalis en tant que promoteurs conduit non seulement à augmenter la conversion de CO2 et H2, mais augmente également la sélectivité des produits visés fortement, des alcools supérieurs. Le catalyseur 0.5K30CuFeCNTs possède une productivités les plus élevées (370.7 g ∙ kg-1 ∙ h-1) d'alcools supérieurs à 350 ° C et 50 bar. / CO2 is a clean carbon source for the chemical reactions, many researchers have studied the utilization of CO2. Higher alcohols are clean fuel additives. The synthesis of higher alcohols from CO hydrogenation has also been studied by many researchers, but there are few literatures about the synthesis of higher alcohols from CO2 hydrogenation, which is a complex and difficult reaction. The catalysts that used for higher alcohols synthesis need at least two active phases and goodcooperation. In our study, we tested the Co. Cu. Fe spinel-based catalysts and the effect of supports (CNTs and TUD-1) and promoters (K, Na, Cs) to the HAS reaction. We found that catalyst CuFe-precursor-800 is beneficial for the synthesis of C2+ hydrocarbons and higher alcohols. In the CO2 hydrogenation, Co acts as a methanation catalyst rather than acting as a FT catalyst, because of the different reaction mechanism between CO hydrogenation and CO2 hydrogenation. In order to inhibit the formation of huge amount of hydrocarbons, it is better to choose catalysts without Co in the CO2 hydrogenation reaction. Compared the functions of CNTs and TUD-1, we found that CNTs is a perfect support for the synthesis of long-chain products (higher alcohols and C2+ hydrocarbons). The TUD-1 support are more suitable for synthesis of single-carbon products (methane and methanol).The addition of alkalis as promoters does not only lead to increase the conversion of CO2 and H2, but also sharply increased the selectivity to the desired products, higher alcohols. The catalyst 0.5K30CuFeCNTs owns the highest productivities (370.7 g∙kg-1∙h-1) of higher alcohols at 350 °C and 50 bar.

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.

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]

Orientador: Eduardo Augusto Caldas Batista / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-19T16:55:35Z (GMT). No. of bitstreams: 1 Ferreira_MarcelaCravo_M.pdf: 3959927 bytes, checksum: bd67f499a341015a91495d52b9e90d61 (MD5) Previous issue date: 2012 / Resumo: O óleo fúsel é um resíduo obtido das destilarias de etanol carburante, constituído por uma mistura de álcoois superiores, como álcool isoamílico, álcool isobutílico, dentre outros. Esses álcoois são classificados como congêneres da fermentação alcoólica e devem ser retirados na coluna de retificação, pois tendem a se acumular na mesma. Em países onde há uma grande produção de etanol combustível, como o Brasil, alternativas para a utilização dos resíduos gerados nesse processo são de grande importância para tornar a produção de etanol menos poluidora e mais rentável. O baixo preço do óleo fúsel e seu elevado teor de álcool isoamílico, além do elevado volume de óleo fúsel produzido pelo Brasil anualmente, justificam o desenvolvimento de tecnologias para o fracionamento dessa mistura. Sob o ponto de vista técnico-econômico, a utilização do álcool isoamílico presente no óleo fúsel como precursor de ésteres de aroma, bem como ésteres lubrificantes, torna-se uma alternativa atrativa. Sendo assim, o objetivo desse trabalho foi estudar o processo de destilação industrial do óleo fúsel para obtenção do álcool isoamílico utilizando o simulador Aspen Plus. Em uma primeira etapa, foram realizados experimentos em uma coluna de destilação piloto e os resultados obtidos foram comparados com os simulados para o mesmo processo, indicando boa concordância entre os dados. Em seguida, foram analisadas, por cromatografia gasosa amostras de óleo fúsel coletadas em usinas de etanol carburante, para a caracterização dessa mistura. Posteriormente realizou-se uma investigação do equilíbrio de fases, Equilíbrio Líquido-Vapor (ELV) e Equilíbrio Líquido-Líquido (ELL), dos componentes envolvidos nessa mistura, sendo realizado o ajuste de alguns parâmetros. Foram realizados estudos preliminares da mistura binária Água/Álcool Isoamílico e da mistura ternária Água/Álcool Isoamílico/Etanol que embasaram as propostas de configuração para o sistema multicomponente. Com o auxílio da ferramenta de planejamento experimental, foram definidos parâmetros operacionais e construtivos para as duas configurações propostas. Duas novas composições de alimentação foram testadas, o que permitiu o desenvolvimento de uma última planta de purificação do óleo fúsel. Esta configuração resultou em uma recuperação de 99,52 % de álcool isoamílico e em um consumo total de 0,8311 kg de vapor por kg de produto contendo os isômeros álcool isoamílico (81,80 % m/m) e álcool amílico ativo (17,81 % m/m) / Abstract: Fusel oil is a byproduct obtained from fuel ethanol distilleries, composed by a mixture of high alcohols like isoamyl alcohol, isobutanol, among others. These alcohols are classified as congeners of alcoholic fermentation and they must be withdrawn from rectifying column because they tend to accumulate in this column. In countries where there is a large production of fuel ethanol, like Brazil, alternatives for the use of byproducts generated in this process are of great importance to make the ethanol production less polluting and more profitable. The low price of fusel oil and its high content of isoamyl alcohol, besides the high volume of fusel oil produced annually, justify the development of technologies to separate this mixture. From the technical-economic point of view, the use of isoamyl alcohol as a precursor of esters of aroma and lubricant becomes an attractive alternative. Thus, this work aimed to study the industrial distillation process of fusel oil to obtain isoamyl alcohol using Aspen Plus simulator. In a first step, experiments were performed in a pilot distillation column and the results were compared with those simulated for the same process, indicating good agreement between the data. Then, samples of fusel oil collected in industrial mills were analyzed by gas chromatography in order to characterize this mixture. Later an investigation was carried out of phase equilibria, Vapor-Liquid Equilibrium (VLE) and Liquid-Liquid Equilibrium (ELL) for the components involved in this mixture, and some parameters were adjusted. Preliminary studies of the binary mixture Water/Isoamyl Alcohol and the ternary mixture Water/Isoamyl Alcohol/Ethanol were conducted and, based on them, configurations for the multicomponent system were proposed. With the aid of the tool of experimental design, some operational and constructive parameters were defined for the two proposed configurations. Two new compositions of feed stream were tested, which allowed the development of one last purification plant of fusel oil. This configuration resulted in a recovery of 99.52 % of isoamyl alcohol and in a total consumption of 0.8311 kg steam per kg of product containing the isomers isoamyl alcohol (81.80 % w/w) and active amyl alcohol (17.81 % w/w) / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos