The hydroformylation of olefins is one of the most important homogeneously catalyzed processes in industry to produce bulk chemicals. Despite the high catalytic activities and selectivity’s using rhodium-based homogeneous hydroformylation catalysts, catalyst recovery and recycling from the reaction mixture remain a challenging topic on a process level. Therefore, technical solutions involving alternate approaches with heterogeneous catalysts for the conversion of olefins into aldehydes have been considered and research activities have addressed the synthesis and development of heterogeneous rhodium-based hydroformylation catalysts. Different strategies were pursued by different groups of authors, such as the deposition of molecular rhodium complexes, metallic rhodium nanoparticles and single-atom catalysts on a solid support as well as rhodium complexes present in supported liquids. An overview of the recent developments made in the area of the heterogenization of homogeneous rhodium catalysts and their application in the hydroformylation of short-chain olefins is given. A special focus is laid on the mechanistic understanding of the heterogeneously catalyzed reactions at a molecular level in order to provide a guide for the future design of rhodium-based heterogeneous hydroformylation catalysts.

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Chapter 1: Metal carbenoids in organic synthesis The chapter describes the phenomena of metal carbenoid insertion reactions in two parts: Part A, and Part B. The study of N-tosylhydrazones as diazo precursor was commenced by Jose Barluenga in 2007,1 which demonstrated an in-situ generation of diazo species and trapping of that with low valent palladium catalyst (Scheme 1). Later, this palladium-carbenoid assumption was supported by few reports. Some of these discoveries were by D. F. Taber in 1986 followed by van Vranken in 1999 & 2001.2 These studies of palladium carbenes were supplemented by several groups in subsequent years. The consequent developments with N-tosylhydrazones as diazo source were very fruitful and produced exceptional chemical transformations in recent years. Though the precursor is also vastly customary for other metals such as Cu, Ni, Rh and Co, the primary focus has been given to Pd catalysis due to its wide utility and applicability. 1) Barluenga, J.; Moriel, P.; Valdes, C.; Aznar, F. Angew. Chem., Int. Ed. 2007, 46, 5587. 2) (a) Taber, D. F.; Amedio, J. C., Jr.; Sherrill, R. G. J. Org. Chem. 1986, 51, 3382. (b) Hoye, T. R.; Dinsmore, C. J.; Johnson, D. S.; Korkowski, P. F. J. Org. Chem. 1990, 55, 4518. (c) Greenman, K. L.; Carter, D. S.; Van Vranken, D. L Tetrahedron 2001, 57, 5219. 3) Palladium catalysed coupling of tosylhydrazones with aryl and heteroaryl halides in the absence of external ligands: synthesis of substituted olefins, Ojha, D. P.; Prabhu, K. R. J. Org. Chem., 2013, 78, 12136. Modes of reactivity of a metal-carbene Scheme 1 Cascade carbene migratory insertion process Part A: Ligand-free coupling of tosylhydrazones with aryl & heteroaryl halides In this part, Palladium catalysed cross-coupling reaction of hydrazones with aryl halides in absence of an external ligand is reported. The versatility of this coupling reaction has been demonstrated by showcasing the selectivity of coupling reaction in presence of hydroxyl and amine functional groups. This method allows synthesizing a variety of heterocyclic compounds, which are otherwise difficult to access from traditional methods. Application of the present methodology is validated in tandem reaction of ketones to the corresponding substituted olefins in a single pot experiment. Few examples are illustrated below in Scheme 2.3 Scheme 2: Scope of aryl halide coupling with tosylhydrazones Part B: Pd-catalysed Synthesis of Highly Branched Dienes The regioselective formation of highly branched dienes is a challenging task. Design and exploration of alternative working models to achieve such a regioselectivity to accomplish highly branched dienes is considered to be a historical advancement of Heck reaction to construct branched dienes. On the basis of the utility of carbene transfer reactions, in the reaction of hydrazones with Pd(II) under oxidative conditions, we envisioned obtaining a Pd-bis-carbene complex with α-hydrogens, which can lead to branched dienes. Herein, we report a novel Pd catalyzed selective coupling reaction of hydrazones in presence of tert-BuOLi and benzoquinone oxidant to form corresponding branched dienes (Scheme 3).4 The utility of the Pd catalyst for cross-coupling reactions for synthesizing branched conjugated dienes are rare. The reaction is very versatile and compatible with a variety of functional groups and is useful in synthesizing heterocyclic molecules. We anticipate that this Pd-catalyzed cross-coupling reaction will open new avenues for synthesizing useful compounds. 4) Pd-catalyzed cross-coupling reactions of hydrazones: regioselective synthesis of highly branched dienes, Ojha, D. P.; Prabhu, K. R. J. Org. Chem., 2012, 77, 11027. 5) Furrow, M. E.; Myers, A. G. J. Am. Chem. Soc. 2004, 126, 5436. 6) Taber, D. F.; Guo, P.; Guo, N. J. Am. Chem. Soc. 2010, 132, 11179. Scheme 3: diene synthesis via bis-carbene insertion process Chapter 2: Tosylhydrazones: Role in modern day organic synthesis In recent days, hydrazone based reactions are focused on the donor-acceptor ability of the hydrazones or the in-situ generated diazo species (Scheme 4). This commenced with the Myers’s report in 2004,5 which simplifies the Barton vinyl halide preparation with a remarkable revision on synthesis of alkyl-silyl-hydrazones and its applications. Improved methods of using tosylhydrazones were demonstrated by Aggarwal in successive years. Cycloadditions were implemented by Douglass F. Taber. 6 This study was enriched in a quite fascinating way by several groups such as Jose Barluenga, with many reductive coupling reactions and 1, 3-dipolar reactions. Thomson, in a very interesting report shows the traceless petasis reaction with hydrazones and also worked in many other prospects such as three component reactions and the acid catalysed [3+3] sigmatropic reactions of hydrazones. 7 Wang has also impressed with very attractive transformations in the past decade. 8 7) Thomson, R. J. et al. Nat. Chem. 2009, 1, 494. 8) Xiao, Q.; Zhang, Y.; Wang, J. Acc. Chem. Res. 2012, 46, 236. 9) Regioselective Synthesis of vinyl halides, vinyl sulfones, and alkynes: A tandem intermolecular nucleophilic and electrophilic vinylation of tosylhydrazones, Ojha, D. P.; Prabhu, K. R. Org. Lett. 2015, 17, 18. Scheme 4: Trapping diazo species in intermolecular fashion Part A: Synthesis of vinyl halides Trapping diazo species in an intermolecular fashion by attack of two independent ions (a cation followed by an anion) in tandem at the carbene center is unprecedented. As part of our efforts on the utility of tosylhydrazones, herein we report a novel approach of using ambiphilic diazo species to perform a tandem attack of a nucleophile followed by an electrophile in an intermolecular fashion for synthesizing various types of vinyl halides. A few representative examples are shown in Scheme 5.9 Scheme5: Synthesis if vinyl halides Part B: Synthesis of vinyl sulfones Vinyl sulfones are potential synthetic targets due to their presence in biologically and pharmaceutically important molecules ranging from small natural metabolites to proteins, and have found widespread applications in biological research as covalent protease inhibitors. Vinyl sulfones represent one of the important sulfur containing functional groups in organic chemistry, which are generally synthesized through elimination reactions, oxidation of vinyl sulfides or witting reactions using multistep sequence. Following this technique, we were able to synthesize a variety of vinyl sulfones with rich mechanistic features in a single step. A few such examples are documented in Scheme 6.9 Scheme 6: synthesis of vinyl sulfones Part C: Synthesis of alkynes The functional group conversion to achieve alkyne frameworks are generally a difficult transformation. There are very few limited and tedious processes are available in literature, mainly containing multi-step procedures. Additionally these reactions are require harsh conditions. Considering all these factors, there is a need for developing methods to synthesize alkynes from common functional groups under mild reactions conditions. In a similar way, to introduce different halogens at the same carbon, we expected the eliminations of the leaving groups in tandem formed alkynes. After extensive screening studies, it was pleasing to find that the reaction of tosylhydrazones with NCS−BTEAC, NBS−TBAB, or NIS−TBAI combination in presence of K2CO3 in dioxane as solvent at 110 °C can furnish corresponding acetylene derivatives in good yields. Few examples are shown in Scheme 7.9 Scheme 7: Trapping diazo species in intermolecular fashion Chapter 3: Pd catalysed hydroboration This chapter shows a hydroboration study of terminal alkynes in a highly regioselective manner (Scheme 8). Organoboron derivatives have become essential intermediates in organic and medicinal chemistry. Pioneering contributions are made by Brown and Akira Suzuki, who both instigated the development of new synthetic tools for the introduction of boron atoms onto organic molecules. 10 10) (a) Barbeyron, R.; Benedetti, E.; Cossy, J.; Vasseur, J.-J.; Arseniyadis, S.; Smietana, M. Tetrahedron 2014, 70, 8431. (b) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457. 11) Pd-Catalysed regioselective borylation of alkynes: A ligand controlled synthesis of α- and β vinyl boronates (manuscript submitted). Scheme 8: possibility of site selectivity in hydroboration Part A: Pd-catalysed regioselective borylation of alkynes: A ligand controlled synthesis of α and β – vinyl boronates The metal catalyzed borylations of alkynes proceeds in a two-step process. Initially M-Bpin species undergo an addition onto the alkynes to generate organometallic species followed by quenching of the organometallic species with electrophiles. The addition M-Bpin species is regioselective governed by the steric and electronics factors of both metal complex as well as alkyne substituents. In this direction, a palladium catalysed α-selective borylation was achieved for terminal alkynes. A broad range of substrates were successfully borylated under optimized reaction conditions with very high selectivity. Interestingly, the selectivity was reversed to terminal site by using a NHC ligand. A few examples are shown in Scheme 9.11 Scheme 9: α & β-vinyl boronates Chapter 4: Pd/borane unit: Behavior towards isomerization vs reduction of alkenes This study presents a unique behaviour of palladium-boronate unit responsible for olefin chain walking and olefin reduction reactions (Scheme 10). The catalytic system stands efficient against both functionalized and unfunctionalized olefin isomerization as well as reductions. This study has been presented in two parts. Scheme 10: isomerization vs reduction Part A: Pd/ boronates or borane unit as efficient catalytic systems for olefin chain walk This study presents the behaviour of palladium-boronate unit responsible for olefin chain walking. The catalytic system is efficient for both functionalized and unfunctionalized olefin isomerizations (Scheme 11). Cycloisomerization of transient conjugated alkenes to synthesize heterocycles are prominent applications of this technique. The system describes a concept of olefin activation by coordination with Pd-borane complex, this complex assists in a facile [1,3]-hydride shift. This technique allows us to facilitate an isomerization in functionalized as well as unfunctionalized olefinic systems. Considering the substrates scope, the catalytic cycle tolerates various sensitive functional groups and shows good selectivity. In the following Scheme 11 few examples are depicted.12 12) Palladium/boron catalytic unit for olefin chain-walk (manuscript under preparation). Scheme 11: chain-walking of olefins. Part B: Palladium catalysed boronate promoted alkene reduction in water In this work, water has been employed as a source of hydrogen. The reduction of alkenes was achieved using Pd catalyst in presence of bis(pinacolato)diboron and H2O. In this aspect, the utility of water as hydrogen equivalent is the pertinent as well as beneficial with many advantages. Few representative examples are shown in Scheme 12.13 13) Pd-Catalysed homogeneous hydrogenation of olefins by using water as hydrogen source (manuscript under preparation). Scheme 12: synthesis of alkenes reduced products.

The influence of catalyst characteristics, i.e., acidity and porosity on the product distribution in the cracking of triglyceride-rich biomass under fluid catalytic cracking (FCC) conditions is reported. It has found that the degradation degree of triglyceride molecules is strongly dependent on the catalysts’ acidity. The higher density of acid sites enhances the conversion of triglycerides to lighter products such as gaseous products and gasoline-range hydrocarbons. The formation of gasolinerange aromatics and light olefins (propene and ethene) is favored in the medium pore channel of H-ZSM-5. On the other hand, heavier olefins such as gasoline-range and C4 olefins are formed preferentially in the large pore structure of zeolite Y based FCC catalyst (Midas-BSR). With both catalysts, triglyceride molecules are mainly converted to a mixture of hydrocarbons, which can be used as liquid fuels and platform chemicals. Hence, the utilization of the existing FCC units in conventional petroleum refineries for processing of triglyceride based feedstock, in particular waste cooking oil may open the way for production of renewable liquid fuels and chemicals in the near future. / Bài báo trình bày kết quả nghiên cứu khả năng tích hợp sản xuất nhiên liệu sinh học và hóa phẩm từ nguồn nguyên liệu tái tạo sinh khối giầu triglyceride bằng công nghệ cracking xúc tác tấng sôi (FCC) trong nhà máy lọc dầu. Kết quả nghiên cứu cho thấy xúc tác có ảnh hưởng mạnh đến hiệu quả chuyển hóa triglyceride thành hydrocarbon. Tính acid của xúc tác càng mạnh thì độ chuyển hóa càng cao và thu được nhiều sản phẩm nhẹ hơn như xăng và các olefin nhẹ. Xúc tác vi mao quản trung bình như H-ZSM-5 có độ chọn lọc cao với hợp chất vòng thơm thuộc phân đoạn xăng và olefin nhẹ như propylen và ethylen. Với kích thước vi mao quản lớn, xúc tác công nghiệp FCC dựa trên zeolite Y ưu tiên hình thành C4 olefins và các olefin trong phân đoạn xăng. Ở điều kiện phản ứng của quá trình FCC, triglyceride chuyển hóa hiệu quả thành hydrocarbon mà có thể sử dụng làm xăng sinh học cho động cơ và olefin nhẹ làm nguyên liệu cho tổng hợp hóa dầu.

A reação de transformação de MeOH em olefinas leves foi investigada sobre zeólitas HZSM-5 com razões SiO2/Al2O3 (SAR) iguais a 30, 80 e 280. As propriedades ácidas e texturais da amostra com SAR 30 foram modificadas por impregnação com ácido fosfórico. A caracterização físico-química das amostras foi realizada empregando-se as técnicas de FRX, fisissorção de N2, DRX, DTP de NH3 e IV com adsorção de piridina. O desempenho catalítico das mesmas foi comparado tanto em condições reacionais similares (mesma T, pressão parcial de MeOH e WHSV) como em condições de isoconversão. Verificou-se, que quanto maior a SAR da zeólita, menor a densidade total e a força dos sítios ácidos presentes, sendo este efeito mais significativo para os sítios de Brönsted. O efeito do aumento da SAR favoreceu a estabilidade catalítica e a formação de olefinas leves, principalmente propeno. No caso das amostras contendo fósforo, foi observada uma redução linear na área específica BET e no volume de microporos com o aumento do teor de fósforo. Estes resultados, aliados aos obtidos por DRX, sugerem que a redução mais significativa na área específica e no volume de microporos pode ser associada à redução na cristalinidade e à formação de espécies amorfas contendo fósforo, que bloqueariam a estrutura porosa da zeólita. Não se observou alteração significativa na força dos sítios fracos, enquanto a força dos sítios fortes diminuiu significativamente. As amostras apresentando menor SAR e menor teor de fósforo foram mais ativas. Por outro lado, em condições de isoconversão de 916%, a amostra mais seletiva à formação de olefinas foi aquela com maior SAR. Dentre as amostras impregnadas, aquela contendo 4% de fósforo foi a mais seletiva a propeno, enquanto a que continha 6% foi mais seletiva a eteno. A amostra com SAR igual a 280 foi investigada variando-se a temperatura de reação (400, 500 e 540C) e a pressão parcial de metanol (0,038; 0,083 e 0,123 atm), através de um planejamento experimental do tipo Box-Benhnken (32). O rendimento otimizado em olefinas leves foi alcançado a 480C e 0,08 atm. O modelo proposto descreveu bem os dados experimentais e evidenciou a existência de uma faixa ótima de temperatura para maximização do rendimento em propeno e eteno, o qual foi também afetado pela pressão parcial de MeOH na faixa estudada. Palavras-chave: ZSM-5, olefinas, propeno, eteno, processo MTO, fósforo. / The MeOH transformation into light olefins was investigated over HZSM-5 zeolites with SiO2/Al2O3 (SAR) = 30, 80 and 280. The acidic and textural properties of the SAR 30 were modified by impregnation with orthophosphoric acid. Textural characterization and physiochemical like FRX, fisisorption of N2, DRX, DTP of NH3 and IR with pyridine adsorption were used. The catalytic performance of the samples evaluated and compared at both isoconversion and iso-operacional. It was verified, that the increase in SAR of the zeolite reduced acid site density and strenght of the acid sites, particularly for the Brönsted acid sites, favoring the catalytic stability and the formation of light olefins, mainly propene. The characterizations indicated a linearr reduction in the specific BET surface area and in the microporous volume with the increase of the phosphorous incorporation. These results, together with over obtained by DRX, suggest that the most significant reduction in the specific area and in the microporos volume can be associated to the reduction in the cristalinity as well as to the formation of amorphous species containing phosphorous, that would block the zeolite porous structure . No significant alteration was observed in the strenght of the weak sites, although the strong acid sites strenght significantly decreased. The low SAR and slow phosphorous incorporation ware more active. On the other hand, at isoconversion conditions (916), the most selective samples to olefins formation were those with high SAR. Among the impregnated samples, the one containing 4% of phosphorous was more selective to olefins. The sample with SAR equal to 280 was investigated under different reaction temperature (400, 500 and 540C) and methanol partial pressure (0,038; 0,083 and 0,123 atm), following Box-Benhnken (32) experimental planning type. The optimized light olefins yield was reached at 480C and 0,08 atm. The proposed model described well the experimental data and evidenced the existence of a range of temperature for maximization of the propene and ethene, which was also affected by the partial pressure of methanol in the studied range.

Additions of carbon-centered radicals to alkenes are useful method for cyclic compounds formation. Manganese(III)-based oxidative free-radical cyclizations, where the radicals are generated and terminated oxidatively, are established as efficient methods for the construction of cyclic molecule. Treatment of a mixture of dimedone, Mn(OAc)3, and Cu(OAc)2 in glacial acetic acid with homobenzonorbornadiene (80) (4h at 50 &amp / #61616 / C) gave furan derivative (107), dihydrofuran adduct (108), in addition to rearranged product (109) as a major product. The reaction run under the same reaction conditions without using Cu(II)acetate for 8h afforded dihydrofuran adduct (108) along with dihydrofuran (110), where no rearranged products could be formed. On the other hand, reflux of alkene 80 with a mixture of acetylacetone, Mn(OAc)3, and Cu(OAc)2 in glacial acetic acid (3h at 50 &amp / #61616 / C) gave oxidative product (131) and rearranged product (132) (major). The reaction run under the same reaction conditions without using Cu(II)acetate for 7h produced, in addition to the oxidative product 131, a dihydrofuran derivative (133). In a second system, we examined the oxidation of benzobarrelene 82 with Mn(OAc)3, and Cu(OAc)2 in glacial acetic acid (1h at 50 &amp / #61616 / C) in presence of dimedone resulted in the formation of five different products rearranged products (148, 149) and a dihydrofuran (109), besides, a mixture containing two major rearranged isomers (150/151). The same reaction was carried out under the same conditions in absence of Cu(II) for 9h and gave the isomeric mixture 150/151 exclusively, and the yield was reduced. The oxidative cyclization of acetylacetone with alkene 82 for 3h at 50 &amp / #61616 / C, afforded in addition to the dihydrofuran (132), two rearranged products (169, 170) and a mixture consisting of two isomers (171/ 172). The isomeric mixture was converted to one product by treatment with methanolic ammonia providing hydroxyl derivative which was oxidized by MnO2 to afford product 174 in a good yield. Additionally, we investigated the behavior of nitrogen bridge in the bicyclic system on the course of the reaction. Oxidation of N-carbethoxy-7-aza-2,3-benzonorbornadiene 83 with dimedone in the presence of Cu(OAc)2 as well as in its absence in glacial acetic acid (2h at 50 &amp / #61616 / C), rearranged product (189) was obtained as the sole product. Regarding the reaction of aza-derivative 83 with acetylacetone in the presence of Cu(OAc)2 (18 h at 50 &amp / #61616 / C), rearranged product 195 was resulted as sole product. The reaction of 83 was also run with out Cu(OAc)2 for 22h and gave the rearranged product 195.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The petrochemical industry is currently strongly based on the production of light olefins ethylene and propylene, which are mainly produced by hydrocarbons from oil. Due to the environmental appeal and unstable oil market scenario, alternative routes to the production of these olefins are being developed, meanly regarding the use of alcohol as raw material. In this context, ethanol is highlighted with Ethanol to Olefins Process (ETO), in which there is catalytic conversion via reactions of dehydration, oligomerization, cracking, isomerization, among others. This work aims to obtain ethylene and propylene from ethanol using ZSM-5 zeolite as catalyst in its acid form. The synthesis of this material was performed using non-conventional sources of silicon and aluminum, kaolin and silica extracted from rice husk ash, and in the absence of nitrogenous templates. The use of seeds was employed together with ethanol, which acts as cotemplate of the zeolitic structure, in different quantities, and in different silica/alumina ratios and crystallisation times. The influence of each of these variables was evaluated with the support of a full factorial experimental design on the final characteristics of the synthesized samples, such as relative crystallinity, chemical composition and textural properties. All samples presented the characteristic crystal structure of ZSM-5 as verified by both X-ray diffractograms and infrared spectra. However, samples with small amounts of seed and ethanol added to short periods of crystallization presented lower crystallinities and specific areas in comparison to other samples. On the other hand, the use of high quantities of seed can lead to the formation of quartz when the crystallization time is extended. With the catalytic tests of ethanol conversion into olefins it was possible to evaluate the influence of synthesis variables, the residence time and the concentration of ethanol in feed, proving the importance of all synthesis variables in the distribution of the reaction products The total conversion of ethanol was observed in all tests made, evidencing the high activity of hZSM-5 in the dehydration of ethanol to ethylene, being the propylene yield strongly influenced by the reaction temperature and characteristics of the catalitic material, with a maximum yield of 27% at 500 °C. The HZSM-5 presented high stability under reaction conditions while maintaining the production of ethylene for more than 40 hours of reaction, whereas the coke formation drastically reduces the production of propylene still in the early hours of reaction. / A indústria petroquímica atualmente está fortemente baseada na produção das olefinas leves eteno e propeno, que são principalmente produzidas através de hidrocarbonetos oriundos do petróleo. Em virtude do apelo ambiental e do instável cenário do mercado de petróleo, rotas alternativas para a produção destas olefinas estão sendo desenvolvidas, principalmente no que tange a utilização de álcoois como matéria-prima. Neste contexto, o etanol ganha destaque com o processo Ethanol to Olefins (ETO), no qual se tem conversão catalítica via reações de desidratação, oligomerização, craqueamento, isomerização, entre outras. O presente trabalho tem por objetivo a obtenção de eteno e propeno através de etanol empregando como catalisador a zeólita do tipo ZSM-5 na forma ácida. A síntese deste material foi realizada utilizando fontes não convencionais de silício e alumínio, o caulim e a sílica extraída da cinza da casca de arroz, e na ausência de direcionadores de estrutura nitrogenados. O emprego de sementes foi adotado juntamente com etanol, que atua como codirecionador da estrutura zeolítica, em diferentes quantidades, assim como em diferentes razões sílica/alumina e tempos de cristalização. A influência de cada uma destas variáveis foi avaliada com o auxílio do planejamento experimental fatorial completo nas características finais das amostras sintetizadas, como cristalinidade relativa, composição química e propriedades texturais. Todas as amostras obtidas apresentaram estrutura cristalina característica da ZSM-5, comprovada tanto nos difratogramas de Raios-X como nos espectros de absorção na região do Infravermelho. Entretanto, as amostras com pequenas quantidades de sementes e de etanol somadas a curtos períodos de cristalização apresentaram cristalinidades e áreas específicas reduzidas em relação às demais amostras. Em contrapartida, o emprego de elevadas quantidades de sementes pode levar a formação de quartzo quando o tempo de cristalização é prolongado. Com os testes catalíticos de conversão de etanol em olefinas foi possível avaliar a influência das variáveis de síntese, do tempo de residência e a concentração de etanol na alimentação, comprovando a importância de todas as variáveis de síntese na distribuição dos produtos da reação. A conversão total de etanol foi observada em todos os testes realizados, evidenciando a elevada atividade da HZSM-5 na desidratação de etanol a eteno, sendo o rendimento a propeno fortemente influenciado pela temperatura de reação e características do material catalítico, com máximo rendimento igual a 27% na temperatura de 500°C. A HZSM-5 apresentou elevada estabilidade nas condições de reação, mantendo a produção de eteno por mais de 40 horas de reação, enquanto que a formação de coque reduz drasticamente a produção de propeno ainda nas primeiras horas de reação.

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2016-10-21T11:11:40Z No. of bitstreams: 1 TeseJRSJ.pdf: 5314232 bytes, checksum: 9352e78958e9a2f45a12e9a77f564bdd (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:37:37Z (GMT) No. of bitstreams: 1 TeseJRSJ.pdf: 5314232 bytes, checksum: 9352e78958e9a2f45a12e9a77f564bdd (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:37:44Z (GMT) No. of bitstreams: 1 TeseJRSJ.pdf: 5314232 bytes, checksum: 9352e78958e9a2f45a12e9a77f564bdd (MD5) / Made available in DSpace on 2016-11-08T18:37:52Z (GMT). No. of bitstreams: 1 TeseJRSJ.pdf: 5314232 bytes, checksum: 9352e78958e9a2f45a12e9a77f564bdd (MD5) Previous issue date: 2015-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / It was studied the catalytic performance of ZSM-12 zeolites modified by desilication in the cracking of naphthenic hydrocarbons. ZSM-12 zeolites with nominal a SiO2/Al2O3 ratio were synthesized during 96 or 144 h under hydrothermal conditions and the obtained zeolites were treated with NaOH solutions under different conditions. The samples were characterized by thermogravimetric analysis (TA), X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 physisorption, temperature programmed desorption of ammonia (NH3-TPD), 27Al MAS NMR spectroscopy, energy-dispersive X-ray spectroscopy (EDX) and infrared spectroscopy (Py-FTIR). The treatment with NaOH solutions under mild conditions was more effective for the ZSM-12 zeolite synthesized during 96 h. For the HZ12-96-0,2 sample, obtained by treatment at 35 °C with 0.2 mol.L-1 NaOH solution during 15 min, it was verified an increase in the external surface area and the formation of mesopores in the range of 2 to 14 nm. On that zeolite occurred a higher yields to light olefins during the cracking of cyclohexane at 400 °C and also in the cracking of methyl and ethylcyclohexane at 450 °C. This result was mainly related to the higher density of acid sites exhibited by the HZ12-96-0,2 zeolite compared with the parent ZSM-12 one, as consequence of the applied alkaline treatment. It was also verified that the ZSM-12 zeolites modified by more severe alkaline treatment (0.5 or 1.0 mol.L-1 NaOH solution at 80 °C for 30 min) presented significant increase of the external surface area and mesopores volume. The catalytic cracking of cyclohexane, methylcyclohexane and ethylcyclohexane at 500 °C, as well as the physicochemical characteristics of the MZ12-96-0,5 zeolite enhanced the formation of light olefins. The highest yield to light olefins was obtained on that zeolite during the cracking of ethylcyclohexane, which increased 9% when compared with the yield obtained on the not modified HZSM-12 zeolite. The selectivity to light olefins on the studied HZSM-12 zeolites was strongly influenced by presence of a side chain in the naphthenic ring (methyl or ethyl), as well as by the employed cracking operating conditions. / Estudou-se o desempenho de zeólitas ZSM-12 modificadas por dessilicalização no craqueamento de hidrocarbonetos naftênicos. Zeólitas ZSM-12 com razão SiO2/Al2O3 igual a 80 foram sintetizadas em 96 ou 144 h sob condições hidrotérmicas. As zeólitas ZSM-12 obtidas foram modificadas sob diferentes condições de tratamento alcalino com soluções de NaOH e posteriormente caracterizadas por termogravimetria, difratometria de raios X, microscopia eletrônica de varredura, fisissorção de nitrogênio, dessorção de amônia à temperatura programada, ressonância magnética nuclear do 27Al, espectroscopia de energia dispersiva de raios X e espectroscopia na região do infravermelho com adsorção de piridina. O tratamento alcalino, sob condições mais brandas, foi mais efetivo para a zeólita ZSM-12 sintetizada em menor tempo de cristalização (96 h). Para a zeólita HZ12-96-0,2, obtida por tratamento com solução de NaOH 0,2 mol.L-1 a 35 °C por 15 min, verificou-se um aumento na área superficial externa e distribuição de tamanho de mesoporos entre 2 e 14 nm. Nessa zeólita, ocorreu um maior rendimento a olefinas leves no craqueamento de cicloexano a 400 °C e, também, no craqueamento de metil- e etil-cicloexano realizado a 450 °C. Esse resultado foi relacionado, principalmente, com a maior concentração de sítios ácidos na zeólita HZ12- 96-0,2, em relação à zeólita HZSM-12 precursora, como consequência do tratamento alcalino. Verificou-se, também, que as zeólitas ZSM-12 modificadas por tratamento alcalino, sob condições mais severas (solução de NaOH 0,5 ou 1,0 mol.L-1 a 80 °C por 30 min), apresentaram aumento significativo de área superficial externa e volume de mesoporos. O craqueamento de cicloexano, metil- e etil-cicloexano realizado a 500 °C, assim como as características físicas e químicas da zeólita MZ12-96-0,5, favoreceram a formação de olefinas leves. O maior rendimento a olefinas leves ocorreu durante o craqueamento do etil-cicloexano sobre essa zeólita, com aumento desse rendimento em torno de 9% quando comparado ao rendimento obtido sobre a zeólita HZSM-12 não modificada. A seletividade a olefinas leves sobre as zeólitas HZSM-12 preparadas neste estudo sofreu forte influência da presença da cadeia lateral no anel naftênico (metil ou etil), assim como também das condições operacionais de craqueamento empregadas.

Made available in DSpace on 2014-12-17T15:01:51Z (GMT). No. of bitstreams: 1 JoseRS_TESE.pdf: 2480554 bytes, checksum: 063a0cad7c7f0aba30894e5fdff5f4a7 (MD5) Previous issue date: 2010-07-30 / The current natural gas production of 52 Mm3d-1 and the large projects for its expansion has been setting new boundaries for the Brazilian industry of oil and gas. So far, one of the biggest challenges regards to the logistics for gas transportation from offshore fields. Therefore, the transformation of natural gas into gasoline, diesel and/or olefins via Fischer-Tropsch synthesis would be an alternative to this matter. In this work, the production of hydrocarbons by Fischer-Tropsch synthesis in a slurry reactor was investigated and a perovskite-type catalyst (LayCu0,4Fe0,6O3 ? d) was used with y varying from 0 to 1 on a molar basis. In addition, Nb2O5 support was also applied in order to observe the selectivity of the produced hydrocarbons by the Fischer-Tropsch process. It is shown that the hydrogen conversion was influenced by the support as well as the different phases of the samples. The kinetic results for the CO2 production suffered great influence with the introduction of the Nb2O5 support throughout the series of samples studied. The catalysts allowed obtaining welldefined cuts of hydrocarbons in the range of C1-C6 and C17-C28, and these results were clearly influenced by the support and the lanthanum content. The higher olefin/paraffin ratio obtained was 1.8 when using a non-supported perovskite with y equal to 0.8. This would indicate the suitability of using this material for the production of olefins / A produ??o atual de 52 milh?es m?dia-1 de g?s natural e os grandes projetos para esta expans?o vem estabelecendo novas fronteiras para a ind?stria nacional de petr?leo e g?s, sendo um dos maiores desafios a log?stica para o transporte do g?s oriundo de campos offshore. Uma alternativa seria usar o g?s natural para a produ??o de gasolina, diesel e/ou olefinas atrav?s da s?ntese de Fischer-Tropsch. No desenvolvimento deste trabalho foi investigado a produ??o de hidrocarbonetos via s?ntese de Fischer-Tropsch em um reator slurry mediante uso de catalisadores do tipo perovskita, LayCu0,4Fe0,6O3?d, onde y sofreu varia??o de 0 at? 1 em base molar. A s?ntese dos catalisadores levou em considera??o o estudo da influ?ncia do teor de lant?nio e do suporte (Nb2O5) na atividade e seletividade da rea??o de Fischer-Tropsch, objetivando a produ??o de hidrocarbonetos. As convers?es de H2 foram sensivelmente influ?nciadas pela presen?a de fases existentes em cada amostra, assim como pelo suporte. Os resultados da cin?tica de produ??o de CO2 sofreram grandes influ?ncias com a introdu??o do suporte em toda a s?rie das amostras produzidas. Os catalisadores empregados permitiram a obten??o de cortes bem definidos de hidrocarbonetos na faixa de C1-C6 e C17-C28, sendo estes resultados claramente influenciados pelo suporte e pela varia??o do teor de lant?nio. A maior rela??o olefina/parafina obtida foi de 1,8 para a perovskita com y igual a 0,8 na amostra n?o suportada, viabilizando o uso deste material na produ??o de olefinas

A reação de transformação de MeOH em olefinas leves foi investigada sobre zeólitas HZSM-5 com razões SiO2/Al2O3 (SAR) iguais a 30, 80 e 280. As propriedades ácidas e texturais da amostra com SAR 30 foram modificadas por impregnação com ácido fosfórico. A caracterização físico-química das amostras foi realizada empregando-se as técnicas de FRX, fisissorção de N2, DRX, DTP de NH3 e IV com adsorção de piridina. O desempenho catalítico das mesmas foi comparado tanto em condições reacionais similares (mesma T, pressão parcial de MeOH e WHSV) como em condições de isoconversão. Verificou-se, que quanto maior a SAR da zeólita, menor a densidade total e a força dos sítios ácidos presentes, sendo este efeito mais significativo para os sítios de Brönsted. O efeito do aumento da SAR favoreceu a estabilidade catalítica e a formação de olefinas leves, principalmente propeno. No caso das amostras contendo fósforo, foi observada uma redução linear na área específica BET e no volume de microporos com o aumento do teor de fósforo. Estes resultados, aliados aos obtidos por DRX, sugerem que a redução mais significativa na área específica e no volume de microporos pode ser associada à redução na cristalinidade e à formação de espécies amorfas contendo fósforo, que bloqueariam a estrutura porosa da zeólita. Não se observou alteração significativa na força dos sítios fracos, enquanto a força dos sítios fortes diminuiu significativamente. As amostras apresentando menor SAR e menor teor de fósforo foram mais ativas. Por outro lado, em condições de isoconversão de 916%, a amostra mais seletiva à formação de olefinas foi aquela com maior SAR. Dentre as amostras impregnadas, aquela contendo 4% de fósforo foi a mais seletiva a propeno, enquanto a que continha 6% foi mais seletiva a eteno. A amostra com SAR igual a 280 foi investigada variando-se a temperatura de reação (400, 500 e 540C) e a pressão parcial de metanol (0,038; 0,083 e 0,123 atm), através de um planejamento experimental do tipo Box-Benhnken (32). O rendimento otimizado em olefinas leves foi alcançado a 480C e 0,08 atm. O modelo proposto descreveu bem os dados experimentais e evidenciou a existência de uma faixa ótima de temperatura para maximização do rendimento em propeno e eteno, o qual foi também afetado pela pressão parcial de MeOH na faixa estudada. Palavras-chave: ZSM-5, olefinas, propeno, eteno, processo MTO, fósforo. / The MeOH transformation into light olefins was investigated over HZSM-5 zeolites with SiO2/Al2O3 (SAR) = 30, 80 and 280. The acidic and textural properties of the SAR 30 were modified by impregnation with orthophosphoric acid. Textural characterization and physiochemical like FRX, fisisorption of N2, DRX, DTP of NH3 and IR with pyridine adsorption were used. The catalytic performance of the samples evaluated and compared at both isoconversion and iso-operacional. It was verified, that the increase in SAR of the zeolite reduced acid site density and strenght of the acid sites, particularly for the Brönsted acid sites, favoring the catalytic stability and the formation of light olefins, mainly propene. The characterizations indicated a linearr reduction in the specific BET surface area and in the microporous volume with the increase of the phosphorous incorporation. These results, together with over obtained by DRX, suggest that the most significant reduction in the specific area and in the microporos volume can be associated to the reduction in the cristalinity as well as to the formation of amorphous species containing phosphorous, that would block the zeolite porous structure . No significant alteration was observed in the strenght of the weak sites, although the strong acid sites strenght significantly decreased. The low SAR and slow phosphorous incorporation ware more active. On the other hand, at isoconversion conditions (916), the most selective samples to olefins formation were those with high SAR. Among the impregnated samples, the one containing 4% of phosphorous was more selective to olefins. The sample with SAR equal to 280 was investigated under different reaction temperature (400, 500 and 540C) and methanol partial pressure (0,038; 0,083 and 0,123 atm), following Box-Benhnken (32) experimental planning type. The optimized light olefins yield was reached at 480C and 0,08 atm. The proposed model described well the experimental data and evidenced the existence of a range of temperature for maximization of the propene and ethene, which was also affected by the partial pressure of methanol in the studied range.