It is challenging to reveal the catalytic mechanism of Cu/ZnO catalysts with multivalent copper and improve the performance of CO2 hydrogenation to methanol. We synthesized Cu/ZnO catalysts with different Cu:Zn ratios using acetylacetone salts as the precursors, in which Cu, Cu2O, CuO coexist. The catalytic activity was significantly associated with the abundance of Cu+ active sites on the surface and the formation of more Cu+-ZnO interfaces. When the ratio of Cu:Zn = 5:4, the catalyst without reduction pretreatment showed good performance, with a CO2 conversion rate of 12.9%, methanol selectivity of 85.1%, and the space-time yield of 0.238 gMeOH gcat−1 h−1. It was suggested that Cu+ tends to closely bind with ZnO, and the preparation method leads to more Cu+-ZnO interfaces. The synergistic interaction between Cu+ and ZnO promoted the adsorption and dissociation of CO2 and H2, verifying its dual effect on CO2 and H2 and promoting CO2 hydrogenation to methanol. CuZnO Cu CO CuZn Zn precursors Cu2O O coexist Cu+ZnO interfaces 54, 54 5 4, 4 5:4 129 12 9 12.9% 851 85 1 85.1% spacetime space time 0238 0 238 0.23 gcat1 gcat gcat− h1 h h−1 H 5: 12.9 8 85.1 023 23 0.2 h− 12. 85. 02 2 0.

The catalytic performance of γ-Fe2O3 nanopowder was investigated in the acetone hydrodeoxygenation (HDO) reaction, an essential catalytic reaction in biomass valorization. Sequential reduction/oxidation thermal pre-treatments of the γ-Fe2O3 nanopowder induced significant structural and electronic modifications that directly impacted its catalytic performance. The co-existence of Fe3+/Fe2+/Fe0 sites led to different reaction pathways (C-C coupling, hydrogenolysis, hydrogenation, and (hydro)deoxygenation) that formed a wide range of products. The correlation of the catalytic and structural data provided a better understanding of C-O, C-C, and C-H bond activation under the HDO reactional stream in the presence of metallic and oxidized phases of iron. This study demonstrates the tunability of FeOx catalysts in the acetone HDO reaction to favor different reaction pathways and the formation of products. It highlights that tailoring active sites is crucial for developing selective and optimized catalysts for the HDO reaction. γFe2O3 γFeO γ Fe2O3 Fe O γ-Fe2O (HDO valorization reductionoxidation reduction oxidation pretreatments pre treatments coexistence co existence Fe3Fe2Fe0 FeFeFe Fe3 Fe2 Fe0 Fe3+/Fe2+/Fe CC C coupling hydrogenolysis hydrogenation hydro deoxygenation (hydro)deoxygenation products CO, CO O, C-O CC, C, C-C CH H iron γFe γFe2O FeO Fe2O Fe3Fe2Fe

Resumen Se sintetizaron cinco hidrotalcitas terciarias conteniendo dos cationes trivalentes: Fe3+ y Al3+, y un catión divalente Mg2+, Co2+, Ni2+ o Zn2+. Se mantuvo una proporción molar [M+3/(M3++M2+)] de 0,22 y una proporción molar de [Fe3+/Al3+] de 0,66; con la excepción de la hidrotalcita MgFeAl cuya proporción fue duplicada a 1,32. Los óxidos de estas hidrotalcitas fueron usados como soportes de la fase activa (Mo) promovida con Co. Hidrotalcitas, óxidos mixtos y sus precursores catalíticos fueron caracterizados por las técnicas de: análisis químico por fluorescencia de rayos X, medidas de superficie, difracción de rayos (DRX), desorción a temperatura programada (TPD-CO2), análisis elemental (C y S) y microscopía electrónica de transmisión de alta resolución. Todos los precursores catalíticos fueron probados en la reacción de hidrodesulfuración de dibenzotiofeno mostrando el siguiente orden de actividad: CoMo/γ-Al2O3 > CoMo/MgFeAl(0,66)> CoMo/MgFeAl(1,32)> CoMo/CoFeAl> CoMo/NiFeAl> CoMo/ZnFeAl. La actividad catalítica y la selectividad hacia la formación de productos de hidrogenación con respecto a la desulfuración directa (HID/DSD) se incrementó a medida que se incrementó la basicidad del catalizador. Estos resultados fueron asociados con la fracción de Mo (f Mo ) y la naturaleza del soporte. Es importante mencionar que los catalizadores: CoMo/MgFeAl(0,66) y CoMo/MgFeAl(1,32) mostraron la más alta selectividad hacia la ruta de hidrogenación comparado con el catalizador de referencia (CoMo/y-Al2O3). Adicionalmente, la actividad del catalizador CoMo/MgFeAL(0,66) hacia la ruta de HID fue la más alta, inclusive superando la actividad del CoMo/y-Al2O3.

Resumo Cinco hidrotalcitas terciárias contendo Fe3+ e Al3+ e Mg2+, Co2+, Ni2+ ou Zn2+ como cátions divalentes foram sintetizadas. Uma razão molar [M+3/(M3++M2+)] de 0,22 e uma razão molar de [Fe3+/Al3+] de 0,66 foram mantidas; com exceção da hidrotalcita MgFeAl cuja razão molar foi dobrada. Os óxidos dessas hidrotalcitas foram utilizados como suportes da fase ativa (Mo) promovida com Co. Hidrotalcitas, óxidos mistos e seus precursores catalíticos foram caracterizados pelas técnicas de análise química por fluorescência de raios X, medições de superfície, difração de raios X (DRX), dessorção de temperatura programada (TPD-CO2), análise elementar (C e S) e microscopia eletrônica de transmissão de alta resolução. Todos os precursores catalíticos foram testados na reação de hidrodessulfuração do dibenzotiofeno apresentando a seguinte ordem de atividade: CoMo/γ-Al2O3 > CoMo/MgFeAl(0,66)> CoMo/MgFeAl(1,32)> CoMo/CoFeAl> CoMo/NiFeAl> Como/ZnFeAl. A atividade catalítica e a seletividade para a formação de produtos de hidrogenação com relação à dessulfuração direta (HID/DSD) aumentaram com o aumento da basicidade do catalisador. Esses resultados foram associados à fração de Mo (fMo) e à natureza do suporte. É importante mencionar que os catalisadores: CoMo/MgFeAl(0,66) e CoMo/MgFeAl(1,32) apresentaram a maior seletividade para a rota de hidrogenação em relação ao catalisador de referência. Adicionalmente, a atividade do catalisador CoMo/MgFeAL(0,66) em direção à via HID foi a mais alta, excedendo inclusive a atividade de CoMo/y-Al2O3.

Abstract Five tertiary hydrotalcites containing Fe3+ and Al3+ (M3+) as trivalent cations, and Mg2+, Co2+, Ni2+ or Zn2+ (M2+) as divalent cations were synthesized. A [M+3/(M3++M2+)] ratio of 0.22 and a [Fe3+/Al3+] ratio of 0.66 were kept for all synthesis with exception of a MgFeAl hydrotalcite whose [Fe3+/Al3+] ratio was duplicated to 1.32. The mixed oxides from these hydrotalcytes were used as supports of the active phase (Mo) promoting with Co. As-synthesized hydrotalcites, supports and their catalytic precursors were characterized by techniques such as chemical analysis by X-ray fluorescence, surface measurements, X-ray diffraction (XRD), CO2 temperature programmed desorption (CO2-TPD), elemental analysis (S and C) and high-resolution transmission electron microscopy (HRTEM). All catalytic precursors were tested in the reactions of dibenzothiophene hydrodesulfurization, showing the following order of activity: CoMo/ γ -Al2O3 > CoMo/MgFeAl(0.66)> CoMo/MgFeAl(1.32)> CoMo/CoFeAl> CoMo/NiFeAl> CoMo/ZnFeAl, The catalytic activity and selectivity towards the formation of hydrogenation products over direct desulfurization (HID/DSD) increased as the basicity of the catalyst increased. These results were associated to (f M ) Mo fraction and the nature of supports. It is important to mention that the catalysts: CoMo/MgFeAl(0.66) and CoMo/MgFeAl(1.32) showed the highest selectivity towards the hydrogenation route compared to the reference catalyst (CoMo/y-Al2O3). Additionally, the activity of the CoMo/MgFeAL(0.66) catalyst towards the HID pathway was the highest, even exceeding the activity of CoMo/y-Al2O3.

Different Al2O3 carriers were synthesized by co-precipitation and sol-gel method. From them, 4%NiO-20%MoO3/Al2O3 catalysts were prepared by incipient wetness impregnation. The catalysts were characterized by X-ray diffraction analysis (XRD), N2 adsorption-desorption, NH3 temperature programmed desorption (TPD) and H2-temperature programmed reduction (TPR) and subsequently used for selective hydrogenation of naphthalene to high-value tetralin. The results showed that Ni-Mo/so-ge Al2O3 (900) exhibited better catalytic performance than Ni Mo/commercial Al2O3, achieving 99.56% naphthalene conversion and 99.43% tetralin selectivity. AlO Al O Al2O coprecipitation co precipitation solgel sol gel method them 4%NiO20%MoO3/Al2O3 4NiO20MoO3Al2O3 NiOMoOAlO 4%NiO 20%MoO3/Al2O3 4 NiO 20 MoO3 MoO 4%NiO-20%MoO3/Al2O impregnation Xray X ray XRD, XRD , (XRD) N adsorptiondesorption, adsorptiondesorption adsorption desorption, adsorption-desorption NH TPD (TPD H2temperature Htemperature H2 H TPR (TPR highvalue high value NiMo/soge NiMosoge Mo/so ge Mo so 900 (900 Mocommercial commercial 9956 99 56 99.56 9943 43 99.43 selectivity NiO20 4%NiO20%MoO3/Al2O 4NiO20MoO3Al2O 4NiO 20MoO3Al2O3 MoOAlO 20%MoO3/Al2O 2 (XRD NiMo soge Moso 90 (90 995 9 5 99.5 994 99.4 NiO2 20MoO3Al2O (9 99. (

Abstract High-carbon structural steel wires were prestressed to various levels in a plasma hydrogenation environment and then pulled in a slow strain rate test (SSRT). The effect of plasma hydrogenation under different prestressing levels on the material's tensile response and hydrogen embrittlement was noted. It was found that the ultimate tensile strength (UTS), yield strength, and ductility of the steel wire samples are decreased by plasma hydrogenation and prestressing levels. The more drastic decrease in the UTS, yield strength, and ductility is found in the plasma hydrogenated prestressing steel to a higher prestressing level. Moreover, the hydrogen embrittlement index of the steel wire samples is significantly increased by plasma hydrogenation and prestressing level. The highly plasma hydrogenated prestressing steel wire samples exhibit complete brittle fracture. A mixed mode of fracture, i.e., ductile and brittle, was observed at the surface of the plasma hydrogenated prestressing steel wire samples at lower levels. The hydrogen embrittlement areas at the fracture surfaces of steel wire samples are observed to increase with plasma hydrogenation and prestressing levels. More severe hydrogen cracking and blistering resulted in the fracture surfaces of plasma-hydrogenated prestressing steel wire samples with higher levels. Highcarbon High carbon SSRT. SSRT . (SSRT) materials material s noted UTS , (UTS) level Moreover ie i e i.e. plasmahydrogenated (SSRT (UTS i.e

Abstract Glycerol has applications as a raw material in different industrial processes, however, its supply exceeds demand. An alternative to increase the added value of this feedstock is its conversion into high added-value chemical products through dehydration and hydrogenation reactions, from which 1,2-PDO and 1,3-PDO can be obtained. To develop catalysts that increase the conversion and selectivity of these processes, materials of 2% Pt and 10% WO3 supported on SBA-15 were studied. Two methods were used for incipient wetness impregnation: sequential impregnation, with impregnation steps for each species, and co-impregnation, with a single impregnation step for both species. From the analysis of XRD, XRF, N2 isotherms, SEM, EDS, FTIR, and pyridine FTIR spectroscopy, it was possible to observe the influence of these methods on the structural and textural properties. It was verified that the co-impregnation provided a better dispersion of the WO3 species on the surface of the SBA-15 and that the reduction process, for both methodologies employed, showed an improvement in the metallic dispersion. The better dispersion of WO3 species also resulted in a greater formation of Brønsted acid sites for the co-impregnation method, with a predominance of Lewis sites in the structure of the catalysts obtained by both methods. processes however demand addedvalue reactions 1,2PDO 12PDO PDO 1,2 1 2 1,3PDO 13PDO 1,3 3 10 WO SBA15 SBA 15 SBA-1 studied coimpregnation, coimpregnation co XRD XRF N isotherms SEM EDS spectroscopy properties process employed method 2PDO 12 1, 3PDO 13 SBA1 SBA-

The hydrogenation of α-oximinoketones in methanol/HCl afforded α-aminoketones, which were applied without purification to the synthesis of 4-imidazolin-2-ones and 2-thiones, including chiral derivatives. The latter two series were obtained in high yields by a heteroannulation reaction of α-aminoketones with isocyanates and isothiocyanates, respectively. A double condensation of the α-aminoketones with two mol equivalents of the isocyanates produced a series of 4,5-dialkyl-N,3-diaryl-2-oxo-2,3-dihydro-1H-imidazole-1-carboxamides. With isothiocyanates, a single condensation reaction furnished a series of 4,5-dialkyl-1-aryl-1H-imidazole-2(3H)-thiones, which underwent alkylation with alkyl halides to form the corresponding 1-aryl-2-thioalkyl-1H imidazoles in high yields.

Abstract ASTM A 182 F22 steel, used in components subsea for oil extraction, are previously buttered with ductile metal such as Inconel 625, before being welded to steel pipes similar to ASTM A36 steels. The thermal buttering weld cycle provides the formation of high hardness micro-phases and carbides at the interface between F22 steel and the buttering with Inconel, which when in contact with hydrogen, originating from the cathodic protection applied to these equipment, can lead to the embrittlement of this region, causing fragile fractures. In this work, ASTM A 182 F22 steel, buttered with Inconel 625 and welded to A36 steel, submitted to post-weld heat treatment without hydrogenation and subjected to cathodic protection for hydrogen permeation were submitted to fracture toughness test. The welds and buttering were done using GMAW process with AWS ERNiCrMo-3 wire as filler and buttering metal and a mixture of Ar and He as shield gas. The results indicated a 56% of area reduction, and 15% in the elongation values in the tensile tests, in addition to a 13.3% reduction in the CTOD value, for welded joints subjected to hydrogen permeation, which showed a quasi-cleavage fracture mechanism.

A new methodology for immobilizing a triazolium salt onto polyethylene glycols (PEG) was developed. The immobilization is a two-step reaction, involving the tosylation of PEGs followed by a neat reaction between the PEG tosylates and the triazole. It is a high-yielding reaction conducted under mild conditions with a simple workup procedure. Hence, the salt 1-benzyl-4-phenyl-1H-1,2,3-triazolium iodide was immobilised onto PEGs of varying chain lengths (PEG300_8000) to yield various polymeric ionic liquids (PILs). All the PIL compounds were characterised by spectroscopic analysis and utilised as homogeneous metal-free organocatalysts for the transfer hydrogenation of ketones to alcohols in isopropanol as solvent and hydrogen source. The metal-free PIL catalysts showed activity for transforming acetophenone to 1-phenyl alcohol at up to 87% conversion. The representative PEG600 system was recycled three times with minimal loss in activity. The mechanism of a possible catalyst leaching was investigated using computational calculations. The results reveal that the promoter, isopropanol, also promotes the leaching of the triazole from the PEG backbone.

Resumen Productos de Knoevenagel diversamente sustituidos fueron sometidos a reducción con una solución de NaBH4 en MeOH/p-dioxano a 70 oC. A través de este proceso, se alcanzó la reducción selectiva de sus dobles enlaces C=C en todos los casos. Las condiciones de reducción establecidas toleró una variedad de grupos funcionales, aunque productos simples de condensación aldólica o de Claisen-Schmidt mostraron menos selectividad hacia la reducción del doble enlace C=C, y por el contrario, condujo específicamente a la reducción de los grupos C=O. Adicionalmente, la selectividad de nuestras condiciones de reducción mediadas por NaBH4 fue comparada con la clásica hidrogenación catalítica mediada por Raney-Nickel para encontrar algunas similitudes y diferencias. Así mismo, se propuso una secuencia de pasos mecanísticos, con el fin de intentar explicar el proceso de reducción selectiva mediada por NaBH4.

Abstract Diversely substituted Knoevenagel products were subjected to reduction with NaBH4 in MeOH/p-dioxane solution at 70 oC. Selectively reduction of their C=C double bond was achieved in all cases. Reduction conditions tolerated a variety of functional groups although simple aldolic or Claisen-Schmidt products showed to be less selective toward C=C reduction and on the contrary C=O bond was reduced under these reaction conditions. Additionally, selectivity of the NaBH4-mediated chemical reduction was compared with the classical Raney-Nickel-mediated catalytic hydrogenation in order to find similarities and differences. Moreover, trying to explain the selective NaBH4-mediated reductive process a plausible mechanistic pathway was proposed in this regard.

This work reports the synthesis, structure and catalytic activity of a novel ruthenium(II) complex, [RuCl(dppb)(44bipy)(4-pic)]PF6 (where dppb = 1,4-bis(diphenylphosphine)butane; 44bipy = 4,4’-dimethyl-2,2’-dipyridyl; 4-pic = 4-picoline). The molecular structure and catalytic activity were studied by Fourier transform infrared (FTIR), UV-Vis and nuclear magnetic resonance (NMR) spectroscopies, cyclic voltammetry, and X-ray crystallography, while the electronic structure was investigated by density-functional theory (DFT) and time dependent DFT (TD-DFT) methods. Electrochemical studies showed the substitution of the chlorido ligand from the precursor by the 4-pic ligand, exhibiting the RuII/RuIII process at 1.21 V. The structure of the compound was optimized using DFT simulations and showed data similar to the X-ray structure. The UV-Vis absorption spectrum showed a good agreement with TD-DFT simulations. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were determined at the Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level. The study of the catalytic activity in the transfer hydrogenation of ketones by the 1H NMR showed efficient transfer hydrogenation reaction at 60 ºC, employing acetophenone as substrate and resulting in a high conversion. The formation of two ruthenium-hydride species was observed.

RESUMO A produção de álcoois pela hidrogenação do CO na presença de um catalisador, normalmente Cu/ZnO/Al2O3, em pressões de 50-100 bar e temperaturas na faixa de 220 a 300 °C, é uma importante rota de produção do metanol. Neste cenário, um novo catalisador foi sintetizado substituindo o ZnO por Nb2O5, que por sua vez, trata-se de uma matéria prima nacional com propriedades semicondutoras semelhantes ao óxido de zinco, sendo pouco investigada até o momento. Deste modo, esta pesquisa tem como objetivo avaliar o desempenho do catalisador Cu/Nb2O5/Al2O3 na reação hidrogenação do CO para produção de álcoois de cadeia curta, em especial o metanol. A síntese do catalisador foi feita via impregnação úmida, e seguiu a mesma proporção (% mássica) do catalisador comercial Hifuel R120 Cu/ZnO/Al2O3, sendo sua composição baseada na seguinte relação 18,7/50,5/30,8, respectivamente. O catalisador foi peletizado e caracterizado pelas técnicas de Fissisorção de N2, Difração de Raios X, Microscopia Eletrônica de Varredura, Microscopia Eletrônica de Transmissão, Dessorção a Temperatura Programada de NH3 e Distribuição de tamanhos de partículas por DLS. Os ensaios reacionais foram conduzidos a 250 ºC e 40 bar, usando uma mistura sintética de H2:CO (White Martins, 99%) de 2:1 em uma unidade experimental, sendo o produto líquido obtido, analisado por cromatografia gasosa e espectroscopia de infravermelho por transformada de Fourier (FTIR). O catalisador apresentou bons resultados na reação de hidrogenação do CO, produzindo principalmente álcoois de cadeia curta, o desempenho do catalisador foi comparado ao do Cu-ZnO-Al, sintetizado neste trabalho para comparação. Além disso, os resultados indicam que é possível atuar no preparo do catalisador ou nas condições reacionais para torná-lo mais seletivo ao metanol e obter uma maior conversão do gás de síntese.

ABSTRACT The production of alcohols by hydrogenation of CO in the presence of a catalyst, normally Cu/ZnO/Al2O3, at pressures of 50-100 bar and temperatures in the range of 220 to 300 ° C, is an important route for methanol production. In this scenario, a new catalyst was synthesized replacing ZnO by Nb2O5. This catalyst is a national raw material with semiconductor properties similar to zinc oxide, which has been little investigated so far. This research aims to evaluate the performance of the Cu/Nb2O5/Al2O3 catalyst in the hydrogenation reaction of CO for the production of short-chain alcohols, in particular or in methanol. The catalyst synthesis was made via wet impregnation, and followed the same proportion (% metric) of the commercial catalyst Hifuel R120 Cu/ZnO/Al2O3, with its specific composition in the following ratio 18,7/50,5/30,8, respectively. The catalyst was pelletized and characterized by the N2 physisorption, X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, Programmed Temperature Desorption and Size Distribution by DLS techniques. Clinical trials were conducted at 250 ºC and 40 bar, using a 2:1 mixture of H2:CO (White Martins, 99%) in an experimental unit the liquid product were analyzed by gas chromatography and infrared spectroscopy Fourier transform (FTIR). The catalyst shows good results in the hydrogenation reaction of CO, producing mainly short chain alcohols, the catalyst performance was compared to Cu-ZnO-Al, synthesized in this work. In addition, the results that can be performed in the preparation of the catalyst or in the reaction conditions to select the most selected filter for methanol and obtain a greater change in the recording gas.

We have prepared several pyrazolyl palladium and nickel complexes ([(L1)PdCl2](1), [(L2) PdCl2](2), [(L3) PdCl2](3), [(L1) NiBr2](4), [(L2) NiBr2](5) and [(L3) NiBr2](6)) by reacting 3,5-dimethyMH-pyrazole (L1), 3,5-di-ferf-butyl-1ZÏ-pyrazole (L2) and 5-ferrocenyl-1Zf-pyrazole(L3) with [PdCl2(NCMe)2] or [NiBr2(DME)] to afford mononuclear palladium and nickel complexes, respectively. These complexes were then investigated as pre-catalysts in the hydrogenation of 2,4-hexadienoic acid (sorbic acid). The active catalysts from these complexes demonstrate significant activities under mild experimental conditions. Additionally, the active catalysts show that the hydrogenation of sorbic acid proceeds in a sequential manner, where the less hindered C=C bond (4-hexenoic acid) is preferentially reduced over the more hindered C=C bond (2-hexenoic acid).

Abstract The synthesis of poly(L-glutamic acid) (PG) was investigated. Reduction of poly(benzyl-L-glutamate) by the palladium/charcoal catalyst proved to be an effective method for obtaining polyglutamic acid pure and particularly exhibiting in the α-helix secondary structure. The structure of this synthetic polypeptide was assessed by infrared spectroscopy, gel permeation chromatography, proton nuclear magnetic resonance spectroscopy, temperature-modulated differential scanning calorimetry and wide-angle powder X-ray diffraction methods. The α-helical PG was, for the first time, combined with multi-walled carbon nanotubes (MWCNTs). The obtained PG was demonstrated to be a promising matrix to disperse MWCNTs, forming MWCNT/PG biocomposites.

ABSTRACT The purpose of this study was to evaluate on the catalytic activity nanostructured systems of ruthenium and rhodium stabilized in ionic liquids derived from imidazole: IL1= butylmethyllimidazole tetrafluoroborate [BMIM][BF4] and IL2= butylmethylimidazole hexafluorophosphate [BMIM][PF6] in the biphasic hydrogenation of eugenol under mild reaction conditions T= 80°C, P= 100psi during 4 hours. The metallic nanoparticles (NPs-M) were synthesized using the ligand hydrogenation displacement reaction for the ruthenium III tris(acetylacetonate), [Ru(acac)3], and bis-μ-cloro-di(1,5-ciclooctadieno) dirhodium(I), [Rh(COD)Cl]2, showing a mean particle size between (2.0±_0.2) nm and (4.0±0.2) nm. The nanostructured systems Rh/IL2, Ru/IL2 and Ru/IL1 show similar activities and different from the Rh/IL1 system. On the other hand, the systems stabilized in the IL1 were more selective towards the formation of the 2-methoxy-4-propylphenol than the systems stabilized in the IL2. Nevertheless, in general, the catalysts were good for hydrogenating eugenol, resulting in Rh/IL1 nanoparticles less reactive than Rh/IL2, Ru/IL1 and Ru/IL2.