- Palladium-catalyzed transformation of renewable oils into diesel components
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A size-controlled palladium nanoparticle catalyst prepared by adsorption of colloidal palladium nanoparticles on barium sulfate is efficient and highly selective in transforming vegetable oils into diesel-like fuel. Preliminary kinetic investigations using model compounds indicated that decarboxylation of aliphatic esters on palladium in a hydrogenrich atmosphere showed a zero-order rate. Hydrogen temperature-programmed desorption measurements revealed that the high-temperature desorption of hydrogen species might be the rate-determining step.
- Han, Junxing,Sun, Hui,Duan, Jinzhao,Ding, Yuqi,Lou, Hui,Zheng, Xiaoming
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Read Online
- Radical-based photoinactivation of fatty acid photodecarboxylases
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Fatty acid photodecarboxylases (FAP) are a recently discovered family of FAD-containing, light-activated enzymes, which convert fatty acids to n-alkanes/alkenes with potential applications in the manufacture of fine and speciality chemicals and fuels. Poor catalytic stability of FAPs is however a major limitation. Here, we describe a methodology to purify catalytically stable and homogeneous samples of recombinant Chlorella variabilis NC64A FAP (CvFAP) from Escherichia coli. We demonstrate however that blue light-exposure, which is required for photodecarboxylase activity, also leads to irreversible inactivation of the enzyme, especially in the absence of palmitate substrate. Photoinactivation is attributed to formation of protein based organic radicals, which were observed by EPR spectroscopy. To suppress photoinactivation, we prepared stable and catalytically active FAP in the dark. The steady-state kinetic parameters of CvFAP (kcat: 0.31 ± 0.06 s?1 and KM: 98.8 ± 53.3 μM) for conversion of palmitic acid to pentadecane were determined using gas chromatography. Methods described here should now enable studies of the catalytic mechanism and exploitation of FAPs in biotechnology.
- Hedison, Tobias M.,Heyes, Derren J.,Hoeven, Robin,Lakavath, Balaji,Sakuma, Michiyo,Scrutton, Nigel S.,Shanmugam, Muralidharan,Tilakaratna, Viranga
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Read Online
- New and Improved Methods for the Radical Decarboxylation of Acids
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Carboxylic acid esters derived from N-hydroxypyridine-2-thione undergo efficient radical chain decarboxylation to the corresponding nor-alkane on treatment with either tri-n-butylstannane or t-butylmercaptan; in the absence of these hydrogen atom donors a smooth decarboxylative rearrangement giving noralkyl 2-pyridyl sulphides is observed.
- Barton, Derek H. R.,Crich, David,Motherwell, William B.
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Read Online
- A Reconstructed Common Ancestor of the Fatty Acid Photo-decarboxylase Clade Shows Photo-decarboxylation Activity and Increased Thermostability
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Light-dependent enzymes are a rare type of biocatalyst with high potential for research and biotechnology. A recently discovered fatty acid photo-decarboxylase from Chlorella variabilis NC64A (CvFAP) converts fatty acids to the corresponding hydrocarbons only when irradiated with blue light (400 to 520 nm). To expand the available catalytic diversity for fatty acid decarboxylation, we reconstructed possible ancestral decarboxylases from a set of 12 extant sequences that were classified under the fatty acid decarboxylases clade within the glucose-methanol choline (GMC) oxidoreductase family. One of the resurrected enzymes (ANC1) showed activity in the decarboxylation of fatty acids, showing that the clade indeed contains several photo-decarboxylases. ANC1 has a 15 °C higher melting temperature (Tm) than the extant CvFAP. Its production yielded 12-fold more protein than this wild type decarboxylase, which offers practical advantages for the biochemical investigation of this photoenzyme. Homology modelling revealed amino acid substitutions to more hydrophilic residues at the surface and shorter flexible loops compared to the wild type. Using ancestral sequence reconstruction, we have expanded the existing pool of confirmed fatty acid photo-decarboxylases, providing access to a more robust catalyst for further development via directed evolution.
- Sun, Yue,Calderini, Elia,Kourist, Robert
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Read Online
- Light-Driven Enzymatic Decarboxylation of Dicarboxylic Acids
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Photodecarboxylase from Chlorella variabillis (CvFAP) is one of the three known light-activated enzymes that catalyzes the decarboxylation of fatty acids into the corresponding C1-shortened alkanes. Although the substrate scope of CvFAP has been altered by protein engineering and decoy molecules, it is still limited to mono-fatty acids. Our studies demonstrate for the first time that long chain dicarboxylic acids can be converted by CvFAP. Notably, the conversion of dicarboxylic acids to alkanes still represents a chemically very challenging reaction. Herein, the light-driven enzymatic decarboxylation of dicarboxylic acids to the corresponding (C2-shortened) alkanes using CvFAP is described. A series of dicarboxylic acids is decarboxylated into alkanes in good yields by means of this approach, even for the preparative scales. Reaction pathway studies show that mono-fatty acids are formed as the intermediate products before the final release of C2-shortened alkanes. In addition, the thermostability, storage stability, and recyclability of CvFAP for decarboxylation of dicarboxylic acids are well evaluated. These results represent an advancement over the current state-of-the-art.
- Chen, Bi-Shuang,Liu, Lan,Zeng, Yong-Yi,Zhang, Wuyuan
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p. 553 - 559
(2021/06/25)
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- Highly stable and selective catalytic deoxygenation of renewable bio-lipids over Ni/CeO2-Al2O3 for N-alkanes
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Ni-based catalysts are easy deactivated in bio-lipids deoxygenation due to metal aggregation and Ni leaching. They also suffer from the hydrocracking of C–C bonds due to strong acidity at high reaction temperature (≥ 300 ℃). Herein, a series of Ni/CeO2-Al2O3 catalysts with different Ce/Al ratio were prepared by one-pot sol-gel method. The characteristic results showed that an appropriate addition of Ce both increase the catalytic activity and stability in bio-lipids deoxygenation. The oxygen vacancies formed by Ce introduction weaken the strong interaction of Ni-Al, thus improving Ni sites dispersion. Additional, Ce-addition in NiCeAl system increases weak and medium acidity and decreases strong acidity, preventing the C–C bond cleavage of hydrocarbon. As the result, the Ni/CeAl-3.0 catalyst afforded a 97.1 % n-C17 yield at 99.9 % MO conversion under 2.5 MPa H2 at 300 ℃ for 6 h. Minor C15-16 alkanes (17 yield). After simple regeneration, n-C17 yield was recovered to 95 %. Furthermore, non-edible bio-lipids (JO and WCO) can be converted to C13-18 alkanes with 95.2 % and 93.8 % yields, respectively.
- Ba, Wenxia,Cui, Huamin,Fu, Lin,Li, Yongfei,Liu, Yuejin
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- A General Approach to Intermolecular Olefin Hydroacylation through Light-Induced HAT Initiation: An Efficient Synthesis of Long-Chain Aliphatic Ketones and Functionalized Fatty Acids
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Herein, an operationally simple, environmentally benign and effective method for intermolecular radical hydroacylation of unactivated substrates by employing photo-induced hydrogen atom transfer (HAT) initiation is described. The use of commercially available and inexpensive photoinitiators (Ph2CO and NHPI) makes the process attractive. The olefin hydroacylation protocol applies to a wide array of substrates bearing numerous functional groups and many complex structural units. The reaction proves to be scalable (up to 5 g). Different functionalized fatty acids, petrochemicals and naturally occurring alkanes can be synthesized with this protocol. A radical chain mechanism is implicated in the process.
- Guin, Joyram,Paul, Subhasis
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p. 4412 - 4419
(2021/02/05)
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- Catalytic ketonization of palmitic acid over a series of transition metal oxides supported on zirconia oxide-based catalysts
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Modification of a ZrO2 based catalyst with selected transition metals dopants has shown promising improvement in the catalytic activity of palmitic acid ketonization. Small amounts of metal oxide deposition on the surface of the ZrO2 catalyst enhances the yield of palmitone (16-hentriacontanone) as the major product with pentadecane as the largest side product. This investigation explores the effects of addition of carefully chosen metal oxides (Fe2O3, NiO, MnO2, CeO2, CuO, CoO, Cr2O3, La2O3 and ZnO) as dopants on bulk ZrO2. The catalysts are prepared via a deposition-precipitation method followed by calcination at 550 °C and characterized by XRD, BET-surface area, TPD-CO2, TPD-NH3, FESEM, TEM and XPS. The screening of synthesized catalysts was carried out with 5% catalyst loading onto 15 g of pristine palmitic acid and the reaction carried out at 340 °C for 3 h. Preliminary studies show catalytic activity improvement with addition of dopants in the order of La2O3/ZrO2 CoO/ZrO2 MnO2/ZrO2 with the highest palmitic acid conversion of 92% and palmitone yield of 27.7% achieved using 5% MnO2/ZrO2 catalyst. Besides, NiO/ZrO2 exhibits high selectivity exclusively for pentadecane compared to other catalysts with maximum yield of 24.9% and conversion of 64.9% is observed. Therefore, the changes in physicochemical properties of the dopant added ZrO2 catalysts and their influence in palmitic acid ketonization reaction is discussed in detail. This journal is
- Aleem, S. A.,Asikin-Mijan, N.,Dolfi, A.,Hussain, A. S.,Sivasangar, S.,Taufiq-Yap, Y. H.,Voon, C. H.
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p. 31972 - 31982
(2021/12/01)
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- Recent trends for clean fuel production by deoxygenation of pure palmitic acid using Ni/C catalyst
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Deoxygenation of triglycerides is one of key processes making possible a convenient production of high quality automotive fuels components (sulfur-, oxygen- and aromatics-free). This reaction was studied over non noble metal catalysts 20wt%Ni/C and performed in batch reactor system (autoclave) by using pure palmitic acid, nhexane as a solvent and 200 psi pressure. The effect of different atmospheres (pure hydrogen, pure nitrogen, and mixture of 50 psi H2/150psiN2) and different temperature range (300 °C-350 °C) under a mixed atmosphere (50 psiH2/150psi N2) were studied in this paper. The main product was n-pentadecane (C15) which the catalyst Ni/C has lower cracking selectivity to light hydrocarbons. The total conversion of carboxylic groups of palmitic acid and the selectivity to C15 in case of pure nitrogen are (22.29% and 12.38%) respectively and in case of hydrogen they are (75.16% and 80.07%) respectively. In case of using H2/N2 as a mixture the total conversion and the selectivity are (81.18% and 75.32%) respectively for Ni/C catalyst. The total conversion increases from 81.18% to 99.99% by increase the temperature from 300 °C to 350 °C. The deoxygenation of palmitic acid over 20wt%Ni/C catalyst indicated that the high selectivity for n-alkane (C15) (75.32%) at 300 °C and reach maximum value (98.11%) at 350 °C. Analysis of liquid products by gas chromatography (GC) was used to determine n-alkane (C15) yield and other products (isomeres, olefins and dimers). Insights pertaining to the reaction scheme and an assessment of the reaction products as liquid transportation fuels are also provided in this contribution.
- Rashad, Ahmed M.,El Sharkawy, Heba M.,Ebiad, Mohamed A.,El sayed, Hessin A.,Tantawy, Ahmed H.,Hebash, Kaouser A.,El sabagh, Seham M.,Taman, Afaf R.
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p. 883 - 892
(2021/02/09)
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- Surfactant-Free Synthesis of Ultrafine Pt Nanoparticles on MoS2Nanosheets as Bifunctional Catalysts for the Hydrodeoxygenation of Bio-Oil
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Hydrodeoxygenation (HDO) of bio-oil is a crucial step for improving the bio-fuel quality, but developing highly dispersed Pt-based catalysts with high selectivity for target alkanes remains a great challenge. This study presents a fast surfactant-free method to prepare the MoS2-supported Pt catalyst for HDO. Ultrafine Pt nanoparticles with sizes of 5 nm can be readily grown on chemically exfoliated MoS2 nanosheets (NSs) via the direct microwave-assisted thermal reduction. The obtained Pt NPs/MoS2 composites show excellent catalytic performance in the conversion of palmitic acid, and the best selectivity (also the yield) of hexadecane and pentadecane is 80.56 and 19.43%, respectively.
- Fan, Xiaobin,Li, Yang,Liang, Junmei,Lin, Qianqian,Peng, Wenchao,Xu, Danyun,Zhang, Fengbao,Zhang, Qicheng
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p. 14710 - 14716
(2020/12/23)
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- An unconventional DCOx favored Co/N-C catalyst for efficient conversion of fatty acids and esters to liquid alkanes
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Cobalt (Co) catalysis has recently attracted significant attention in the field of biomass conversion. However, the fabrication of highly dispersive Co nanoparticles at high metal loading with selective facet exposure to achieve specific selectivity is still questionable. In this work, a nitrogen-doped carbon-supported Co catalyst is fabricated for efficient conversion of fatty acids and esters to liquid alkanes. Nitrogen-doping facilitates a highly uniform dispersion of Co nanoparticles even at a high Co loading of 10 wt% and after recycling for 5 runs. The Co/N-C catalyst affords an unconventional decarbonylation/decarboxylation (DCOx) dominant selectivity probably due to partial reduction of cobalt oxides to α-Co0 with only exposure of the (111) facet. Co-existence of Co and N-C leads to strong Lewis acidity and basicity, facilitating the interaction between catalyst and –COOH group, and some important acid-catalyzed step-reactions. The versatility of the Co/N-C catalyst is demonstrated through conversion of various fatty acids and esters.
- Li, Jiang,Liu, Jiaxing,Zhang, Junjie,Wan, Tong,Huang, Lei,Wang, Xintian,Pan, Runze,An, Zhidong,Vlachos, Dionisios G.
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- Ni-Based heterogeneous catalysts for the transformation of fatty acids into higher yields of O-free hydrocarbons
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A series of novel catalytic materials were synthesized by changing the chemical compounds in the impregnation solutions. A rigid, aromatic and bidentate molecule 1,10-phenanthroline (PhN) was used as a ligand to bind Ni2+species prior to impregnation into a mesoporous KIT-5 support. Thein situsynthesized coordination compounds were impregnated into KIT-5 and the resulting materials exhibited better dispersion of metal species, being the best at a molar ratio Ni?:?PhN = 1?:?1. The materials were tested in the hydrodeoxygenation (HDO) of palmitic acid. We found that highly active and stable catalysts were obtained when using PhN as a chelating agent in the impregnation solution. The selectivity of these materials is remarkable since only O-free molecules were detected in the HDO products. Therefore, Ni-PhN complexes in combination with mesoporous SiO2can be further exploited for the catalytic transformation of biomass feedstocks.
- Aburto, Jorge,Gómez-Pérez, María Teresa,Gómora-Herrera, Diana,Valencia, Diego,Zenteno, Citlalli
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p. 3470 - 3480
(2020/06/25)
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- Conversion of palmitic acid to jet fuel components over Mo/H-ZSM-22 bi-functional catalysts with high carbon reservation
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The optimal preparation conditions of Mo/H-ZSM-22 bi-functional catalysts were obtained via the sublimation phenomenon of MoO3 at high calcination temperatures, which was beneficial for the well-dispersion of MoOx species with 5?10 nm particles. High reduction temperature enhanced the reduction from Mo6+ to Mo4+ and even from Mo4+ to Mo°, which would be beneficial for iso-alkanes formation with higher carbon reservation. Importantly, 89.3 % selectivity of C16 alkanes of which 61.7 % were iso-C16 alkanes were obtained with complete deoxygenation of palmitic acid, which was the highest selectivity of C16 alkanes over Mo/H-ZSM-22 bi-functional catalyst prepared at a calcination temperature of 550 °C and at a reduction temperature of 600 °C. The results would offer a novel candidate of bi-functional catalysts for upgrading of microalgae-based bio-oil to high-value jet fuel components with high selectivity of iso-alkanes and carbon reservation.
- Cao, Hongbin,Shi, Yanchun,Wu, Yulong,Yang, Mingde,Zhang, Jimei
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- Ni(4?Tbustb)3: A robust 16-electron Ni(0) olefin complex for catalysis
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Sixteen-electron Ni(0) complexes bearing trans-stilbene derivative ligands have been shown to display a high degree of stability toward oxidation in the solid state. A structural analysis of a unique family of tris Ni(0) stilbene complexes revealed a remarkable effect of the steric hindrance of the substituents at the para position of the stilbene unit to temperature, oxidation, and degradation in solution. From these analyses, Ni(4?tBustb)3 arose as a long-term air-, bench-. and temperature-stable Ni(0) complex. Importantly, Ni(4?tBustb)3 presents faster kinetic profiles and a broader scope as a Ni(0) source, thus outperforming the previously described Ni(4?CF3stb)3 in a variety of relevant Ni-catalyzed transformations.
- Nattmann, Lukas,Cornella, Josep
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supporting information
p. 3295 - 3300
(2020/10/12)
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- Production of Bio Hydrofined Diesel, Jet Fuel, and Carbon Monoxide from Fatty Acids Using a Silicon Nanowire Array-Supported Rhodium Nanoparticle Catalyst under Microwave Conditions
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Biodiesel was efficiently produced from biomass fatty acids using renewable gas H2 and a reusable heterogeneous catalyst under low-energy-consumption microwave conditions. As the decarboxylation of fatty acids to alkanes is an important transformation in the production of bio hydrofined diesel (BHD) and jet fuel, we herein report the development of a highly active and reusable Rh nanoparticle catalyst supported by a silicon nanowire array (SiNA-Rh) and its application in the decarboxylation of fatty acids to alkanes under mild conditions. More specifically, SiNA-Rh (500 mol ppm) selectively promoted the hydrogenative decarboxylation reaction at 200 °C under microwave irradiation (～40 W) in a H2 atmosphere (10 bar) to afford the corresponding alkanes in high yields selectively. The only coproduct observed was carbon monoxide, an important and essential staple for the chemical industry. Importantly, carbon dioxide formation was not observed. Moreover, the aldehydes were efficiently converted to alkanes by SiNA-Rh, and this catalyst was reused 20 times without any loss in catalytic activity. Finally, to investigate the effects of microwave irradiation on the enhancement of this chemical transformation based on the Si nanorod structures present in the SiNA-Rh catalyst, the effect of the microwave electric field and magnetic field in the microwave to the reaction was experimentally investigated, and the spatial distribution of the electric field intensity around the surface of the Si nanostructure was simulated using the finite element method.
- Baek, Heeyoel,Fujii, Takashi,Fujikawa, Shigenori,Kashimura, Keiichiro,Sato, Takuma,Tsubaki, Shuntaro,Uozumi, Yasuhiro,Wada, Yuji,Yamada, Yoichi M. A.
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p. 2148 - 2156
(2020/02/11)
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- Ultra-low loading of Ni in catalysts supported on mesoporous SiO2 and their performance in hydrodeoxygenation of palmitic acid
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We synthesized a series of new Ni catalysts supported on mesoporous silica KIT-5. The metal loading on this support was varied (0.9-7.0 wt% NiO). The catalysts were characterized by N2 physisorption, powder XRD, XRF spectrometry, UV-vis DRS, H2-TPR, HRTEM and FT-IR with CO. The mesoporous structure is maintained in all the catalytic materials. The increase in the Ni loading resulted in the formation of crystalline phases at the KIT-5 surface. The catalysts were tested in hydrodeoxygenation (HDO) of palmitic acid. The catalytic activity increased with the metal loading, reaching a maximum by using the catalyst with 1.8 wt% NiO. On the other hand, calculation of kinetic parameters indicated the effective utilization of catalytically active Ni particles in the HDO process. Formation of oxygen-free products was higher for the catalyst with higher metal loading in this series. These catalytic materials were compared with a series of Ni catalysts supported on carbon, finding that the Ni/KIT-5 catalysts were much more active in the HDO reaction. These new catalysts supported on the mesoporous silica KIT-5 exhibited high activity with low metal loadings. This feature makes them attractive for their application in the HDO of fatty acids.
- Valencia, Diego,Zenteno, Citlalli,Morales-Gil, Perla,Díaz-García, Leonardo,Gómora-Herrera, Diana,Palacios-González, Eduardo,Aburto, Jorge
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p. 2435 - 2441
(2020/02/20)
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- Hydrogenation of Alkenes Catalyzed by a Non-pincer Mn Complex
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Hydrogenation of substituted styrenes and unactivated aliphatic alkenes by molecular hydrogen has been achieved using a Mn catalyst with a non-pincer, picolylphosphine ligand. This is the second reported example of alkene hydrogenation catalyzed by a Mn complex. Mechanistic studies showed that a Mn hydride formed by H2 activation in the presence of a base is the catalytically active species. Based on experimental and DFT studies, H2 splitting is proposed to occur via a metal-ligand cooperative pathway involving deprotonation of the CH2 arm of the ligand, leading to pyridine dearomatization.
- Rahaman, S. M. Wahidur,Pandey, Dilip K.,Rivada-Wheelaghan, Orestes,Dubey, Abhishek,Fayzullin, Robert R.,Khusnutdinova, Julia R.
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p. 5912 - 5918
(2020/10/30)
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- Hexadecane Conversion on an Alumina–Nickel Catalyst
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Abstract: The conversion of hexadecane on a 4% Ni/Al2O3 catalyst in a temperature range of 20–300°C was studied using IR spectroscopy and catalytic methods. It was found that the dehydrogenation of hexadecane occurred at 20–100°C with the subsequent formation of aromatic products, but the rates of these processes were very low. As the reaction temperature was increased to 200°C, the 4% Ni/Al2O3 catalyst exhibited a maximum activity and high selectivity for the formation of 1-hexadecene, and aromatic compounds and cracking products were present in the reaction products. As the reaction temperature was further increased, the catalytic activity significantly decreased. This was due to the fact that polyaromatic deposits gradually accumulated on the catalyst surface in a temperature range of 200–300°C.
- Chesnokov,Chichkan,Paukshtis,Chesalov, Yu. A.,Krasnov
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p. 439 - 445
(2019/09/04)
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- Paving the way towards green catalytic materials for green fuels: Impact of chemical species on Mo-based catalysts for hydrodeoxygenation
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A series of Mo-based catalysts were synthesized by tuning the sulfidation temperature to produce mixtures of MoO3 and MoS2 as active phases for the hydrodeoxygenation (HDO) of palmitic acid. Differences in the oxidation states of Mo, and the chemical species present in the catalytic materials were determined by spectroscopic techniques. Palmitic acid was used as a fatty-acid model compound to test the performance of these catalysts. The catalytic performance was related to different chemical species formed within the materials. Sulfidation of these otherwise inactive catalysts significantly increased their performance. The catalytic activity remains optimal between the sulfidation temperatures of 100 °C and 200 °C, whereas the most active catalyst was obtained at 200 °C. The catalytic performance decreased significantly at 400 °C due to a higher proportion of sulfides formed in the materials. Furthermore, the relative proportion of MoO3 to MoS2 is essential to form highly active materials to produce O-free hydrocarbons from biomass feedstock. The transition from MoS2 to MoO3 reveals the importance of Mo-S and Mo-O catalytically active species needed for the HDO process and hence for biomass transformation. We conclude that transitioning from MoS2 to MoO3 catalysts is a step in the right direction to produce green fuels.
- Valencia, Diego,Díaz-García, Leonardo,Ramírez-Verduzco, Luis Felipe,Qamar, Amir,Moewes, Alexander,Aburto, Jorge
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p. 18292 - 18301
(2019/07/03)
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- Hydrodeoxygenation of Palmitic and Stearic Acids on Phosphide Catalysts Obtained In Situ in Reaction Medium
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Abstract: Unsupported phosphide catalysts of composition Ni2P and CoP are prepared in situ in the reaction medium from oil-soluble precursors in the course of hydrodeoxygenation of palmitic and stearic acids. The obtained catalysts are characterized by X-ray powder diffraction and X-ray photoelectron spectroscopy; they show high activity in the hydrodeoxygenation of model substrates. After 6 h of the hydrodeoxygenation reactions, the conversion of palmitic acid reaches 93 and 92% and the conversion of stearic acid is as high as 94 and 91% in the presence of nickel phosphide and cobalt phosphide, respectively. It is shown that the catalyst formed in situ can be isolated and recycled.
- Golubeva,Maksimov
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p. 1326 - 1330
(2019/12/30)
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- MANUFACTURING METHOD OF LINEAR HYDROCARBON
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PROBLEM TO BE SOLVED: To provide a manufacturing method of linear hydrocarbon capable of obtaining a constant amount or more of liner hydrocarbon (A) having the same carbon chain length as a raw material and a constant amount or more of linear hydrocarbon (B) having a carbon chain length smaller by one than the raw material at a constant ratio even under a condition of low pressure and low temperature. SOLUTION: There is provided a manufacturing method of linear hydrocarbon for providing 5 mol% or more of linear hydrocarbon (A) having the same carbon chain length as a raw material and 15 mol% or more of linear hydrocarbon (B) having a carbon chain length smaller by one than the raw material so that a molar ratio of between the linear hydrocarbon (A) and the linear hydrocarbon (B), (B/A) becomes 0.9 to 15 by contacting at least one kind of raw material selected from oil and fat or fatty acid and a catalyst in which palladium is carried by zeolite under a condition of a temperature of 250 to 300°C and pressure of 2 MPa or less under hydrogen atmosphere. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0034-0037
(2018/05/24)
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- Light-Driven Enzymatic Decarboxylation of Fatty Acids
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The photoenzymatic decarboxylation of fatty acids to alkanes is proposed as an alternative approach for the synthesis of biodiesel. By using a recently discovered photodecarboxylase from Chlorella variabilis NC64A (CvFAP) we demonstrate the irreversible preparation of alkanes from fatty acids and triglycerides. Several fatty acids and their triglycerides are converted by CvFAP in near-quantitative yield and exclusive selectivity upon illumination with blue light. Very promising turnover numbers of up to 8000 were achieved in this proof-of-concept study.
- Huijbers, Mieke M. E.,Zhang, Wuyuan,Tonin, Fabio,Hollmann, Frank
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supporting information
p. 13648 - 13651
(2018/09/21)
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- Methods to produce fuels
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The present disclosure generally relates to the catalytic conversion of alcohols into hydrocarbon ketones suitable for use as fuels. More specifically, the present disclosure relates to the catalytic conversion of a mixture of isopropanol-butanol-ethanol (IBE) or acetone-butanol-ethanol (ABE), into ketones suitable for use as fuels. The ABE or IBE mixtures may be obtained from the fermentation of biomass or sugars.
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Page/Page column 50; 51
(2018/02/28)
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- Insight into forced hydrogen re-arrangement and altered reaction pathways in a protocol for CO2 catalytic processing of oleic acid into C8-C15 alkanes
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A new vision of using carbon dioxide (CO2) catalytic processing of oleic acid into C8-C15 alkanes over a nano-nickel/zeolite catalyst is reported in this paper. The inherent and essential reasons which make this achievable are clearly resolved by using totally new catalytic reaction pathways of oleic acid transformation in a CO2 atmosphere. The yield of C8-C15 ingredients reaches 73.10 mol% in a CO2 atmosphere, which is much higher than the 49.67 mol% yield obtained in a hydrogen (H2) atmosphere. In the absence of an external H2 source, products which are similar to aviation fuel are generated where aromatization of propene (C3H6) oxidative dehydrogenation (ODH) involving CO2 and propane (C3H8) and hydrogen transfer reactions are found to account for hydrogen liberation in oleic acid and achieve its re-arrangement in the final alkane products. The reaction pathway in the CO2 atmosphere is significantly different from that in the H2 atmosphere, as shown by the presence of 8-heptadecene, γ-stearolactone, and 3-heptadecene as reaction intermediates, as well as a CO formation pathway. Because of the highly dispersed Ni metal center on the zeolite support, H2 spillover is observed in the H2 atmosphere, which inhibits the production of short-chain alkanes and reveals the inherent disadvantage of using H2. The CO2 processing of oleic acid described in this paper will significantly contribute to future CO2 utilization chemistry and provide an economical and promising approach for the production of sustainable alkane products which are similar to aviation fuel.
- Xing, Shiyou,Lv, Pengmei,Yuan, Haoran,Yang, Lingmei,Wang, Zhongming,Yuan, Zhenhong,Chen, Yong
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supporting information
p. 4157 - 4168
(2017/09/07)
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- One-step hydroprocessing of fatty acids into renewable aromatic hydrocarbons over Ni/HZSM-5: Insights into the major reaction pathways
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For high caloricity and stability in bio-aviation fuels, a certain content of aromatic hydrocarbons (AHCs, 8-25 wt%) is crucial. Fatty acids, obtained from waste or inedible oils, are a renewable and economic feedstock for AHC production. Considerable amounts of AHCs, up to 64.61 wt%, were produced through the one-step hydroprocessing of fatty acids over Ni/HZSM-5 catalysts. Hydrogenation, hydrocracking, and aromatization constituted the principal AHC formation processes. At a lower temperature, fatty acids were first hydrosaturated and then hydrodeoxygenated at metal sites to form long-chain hydrocarbons. Alternatively, the unsaturated fatty acids could be directly deoxygenated at acid sites without first being saturated. The long-chain hydrocarbons were cracked into gases such as ethane, propane, and C6-C8 olefins over the catalysts' Br?nsted acid sites; these underwent Diels-Alder reactions on the catalysts' Lewis acid sites to form AHCs. C6-C8 olefins were determined as critical intermediates for AHC formation. As the Ni content in the catalyst increased, the Br?nsted-acid site density was reduced due to coverage by the metal nanoparticles. Good performance was achieved with a loading of 10 wt% Ni, where the Ni nanoparticles exhibited a polyhedral morphology which exposed more active sites for aromatization.
- Xing, Shiyou,Lv, Pengmei,Wang, Jiayan,Fu, Junying,Fan, Pei,Yang, Lingmei,Yang, Gaixiu,Yuan, Zhenhong,Chen, Yong
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p. 2961 - 2973
(2017/02/05)
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- Effect of precursor on the catalytic properties of Ni2P/SiO2 in methyl palmitate hydrodeoxygenation
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The effect of phosphorus precursor on the physicochemical and catalytic properties of silica-supported nickel phosphide catalysts in the hydrodeoxygenation (HDO) of aliphatic model compound methyl palmitate (C15H31COOCH3) has been considered. Nickel aceta
- Shamanaev, Ivan V.,Deliy, Irina V.,Aleksandrov, Pavel V.,Gerasimov, Evgeny Yu.,Pakharukova, Vera P.,Kodenev, Evgeny G.,Ayupov, Artem B.,Andreev, Andrey S.,Lapina, Olga B.,Bukhtiyarova, Galina A.
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p. 30372 - 30383
(2017/02/23)
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- Highly efficient conversion of fatty acids into fatty alcohols with a Zn over Ni catalyst in water
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A new route to convert fatty acids into fatty alcohols under hydrothermal conditions with a Zn reductant over an Ni catalyst is presented. The highest yield of fatty alcohols from fatty acids (81.4%) was achieved at 300 °C for 2 h with a water filling of 40%. The Zn and Ni used in this research were both commercially available powders, and thus this process provides a highly efficient and simple method for reducing fatty acids into fatty alcohols.
- Gao, Xia,Tong, Daming,Zhong, Heng,Jin, Binbin,Jin, Fangming,Zhang, Hua
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p. 27623 - 27626
(2016/04/04)
-
- Fischer–Tropsch synthesis with cobalt catalyst and zeolite multibed arrangement
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The role of zeolite in transformations of hydrocarbons produced from CO and H2 over a Fischer–Tropsch cobalt catalyst under the conditions of multibed arrangement of the cobalt catalyst and the zeolite has been determined. Hydrocarbon conversion over the HBeta zeolite occurs via the bimolecular mechanism, as evidenced by a low methane yield and a high yield of unsaturated gaseous and liquid hydrocarbons. The conversion over the CaA zeolite obeys the unimolecular mechanism, as evidenced by the formation of increased amounts of methane and saturated gaseous C2–C4 hydrocarbons.
- Asalieva, E. Yu.,Kul’chakovskaya,Sineva,Mordkovich,Bulychev
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p. 275 - 280
(2016/06/09)
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- Catalytic performance and deoxygenation path of methyl palmitate on Ni2P/SiO2 synthesized using the thermal decomposition of nickel hypophosphite
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In this paper, the catalytic performance and deoxygenation path of methyl palmitate on Ni2P/SiO2 catalysts were systematically studied in a continuous flow fixed-bed reactor. A series of Ni2P/SiO2 catalysts (with different molar ratios of P/Ni and Ni2P loadings) were synthesized at 300°C using the thermal decomposition of nickel hypophosphite. The increased molar ratio of P/Ni generates phosphate-rich nickel phosphide catalysts and increasing conversion. Interestingly, Ni2P/SiO2 showed significantly higher conversion of methyl palmitate in comparison with Ni/SiO2. Furthermore, an activation temperature higher than 500°C would significantly reduce the catalytic activity, as a result of the sintering of Ni2P. The pressure in a range of 3.0 to 0.5 MPa almost has no effect on the deoxygenation of methyl palmitate, but significantly affects the reaction path and product distribution. Finally, a possible deoxygenation path over Ni2P/SiO2 was proposed based on a GC-MS investigation.
- Guan, Qingxin,Han, Fei,Li, Wei
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p. 31308 - 31315
(2016/04/09)
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- Selective Catalytic Hydrogenolysis of Carbon-Carbon σ Bonds in Primary Aliphatic Alcohols over Supported Metals
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The selective scission of chemical bonds is always of great significance in organic chemistry. The cleavage of strong carbon-carbon σ bonds in the unstrained systems remains challenging. Here, we report the selective hydrogenolysis of carbon-carbon σ bonds in primary aliphatic alcohols catalyzed by supported metals under relatively mild conditions. In the case of 1-hexadecanol hydrogenolysis over Ru/TiO2 as a model reaction system, the selective scission of carbon-carbon bonds over carbon-oxygen bonds is observed, resulting in n-pentadecane as the dominant product with a small quantity of n-hexadecane. Theoretical calculations reveal that the 1-hexadecanol hydrogenolysis on flat Ru (0001) undergoes two parallel pathways: i.e. carbon-carbon bond scission to produce n-pentadecane and carbon-oxygen bond scission to produce n-hexadecane. The removal of adsorbed CO on a flat Ru (0001) surface is a crucial step for the 1-hexadecanol hydrogenolysis. It contributes to the largest energy barrier in n-pentadecane production and also retards the rate for n-hexadecane production by covering the active Ru (0001) surface. The knowledge presented in this work has significance not just for a fundamental understanding of strong carbon-carbon σ bond scission but also for practical biomass conversion to fuels and chemical feedstocks.
- Di, Lu,Yao, Sikai,Li, Mengru,Wu, Guangjun,Dai, Weili,Wang, Guichang,Li, Landong,Guan, Naijia
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p. 7199 - 7207
(2015/12/11)
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- Effective deoxygenation of fatty acids over Ni(OAc)2 in the absence of H2 and solvent
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Different metal acetate salts were systematically examined for the catalytic deoxygenation of stearic acid in the absence of H2 and solvent for the first time. Ni(OAc)2 exhibited the highest activity with 62% yield achieved at 350°C for 4.5 h with only 1 mol% (0.2 wt%) of the catalyst. Even with 0.25 mol% (0.05 wt%) catalyst, around 28% yield was achieved within 2 h at 350°C with 89% selectivity to C17 hydrocarbons. The activity based on C17 yields per Ni was 14.5 mol mol-1 h-1, considerably higher than that in previous reports. The catalytically active species were identified to be in situ generated Ni nanoparticles (8-10 nm) formed from the decomposition of the metal precursor with stearic acid as a stabilizer. A new reaction pathway of alkane formation from stearic acid via anhydride intermediate decarbonylation under an inert gas atmosphere was proposed. The excellent stability of the catalyst was demonstrated by re-adding a substrate to the system, during which the activity remained constant through four consecutive runs. The novel catalytic system was found to be applicable to a range of fatty acids and triglycerides with varying activities.
- Li, Wenjing,Gao, Yongjun,Yao, Siyu,Ma, Ding,Yan, Ning
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p. 4198 - 4205
(2015/08/11)
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- Catalytic Production of Branched Small Alkanes from Biohydrocarbons
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Squalane, C30 algae-derived branched hydrocarbon, was successfully converted to smaller hydrocarbons without skeletal isomerization and aromatization over ruthenium on ceria (Ru/CeO2). The internal CH2-CH2 bonds located between branches are preferably dissociated to give branched alkanes with very simple distribution as compared with conventional methods using metal-acid bifunctional catalysts.
- Oya, Shin-Ichi,Kanno, Daisuke,Watanabe, Hideo,Tamura, Masazumi,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 2472 - 2475
(2015/08/24)
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- Pd/Nb2O5/SiO2 catalyst for the direct hydrodeoxygenation of biomass-related compounds to liquid alkanes under mild conditions
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A simple Pd-loaded Nb2O5/SiO2 catalyst was prepared for the hydrodeoxygenation of biomass-related compounds to alkanes under mild conditions. Niobium oxide dispersed in silica (Nb2O5/SiO2) as the support was prepared by the sol-gel method and characterized by various techniques, including N2 adsorption, XRD, NH3 temperature-programmed desorption (TPD), TEM, and energy-dispersive X-ray spectroscopy (EDAX) atomic mapping. The characterization results showed that the niobium oxide species were amorphous and well dispersed in silica. Compared to commercial Nb2O5, Nb2O5/SiO2 has significantly more active niobium oxide species exposed on the surface. Under mild conditions (170°C, 2.5 MPa), Pd/10 %Nb2O5/SiO2 was effective for the hydrodeoxygenation reactions of 4-(2-furyl)-3-buten-2-one (aldol adduct of furfural with acetone), palmitic acid, tristearin, and diphenyl ether (model compounds of microalgae oils, vegetable oils, and lignin), which gave high yields (>94 %) of alkanes with little C-C bond cleavage. More importantly, owing to the significant promotion effect of NbOx species on C-O bond cleavage and the mild reaction conditions, the C-C cleavage was considerably restrained, and the catalyst showed an excellent activity and stability for the hydrodeoxygenation of palmitic acid with almost no decrease in hexadecane yield (94-95 %) in a 150 h time-on-stream test.
- Shao, Yi,Xia, Qineng,Liu, Xiaohui,Lu, Guanzhong,Wang, Yanqin
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p. 1761 - 1767
(2015/06/02)
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- Synthesis of bulk and supported nickel phosphide using microwave radiation for hydrodeoxygenation of methyl palmitate
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In this paper, we proposed a novel method for preparing bulk and supported Ni2P catalysts under mild conditions. Ni2P and Ni2P/SiO2 were synthesized from nickel hypophosphite precursors at 230 °C for 5 min using a CEM Discover microwave reactor, and the initial reaction temperature is about 202 °C. The catalysts were characterized using XRD, TEM, SEM, XPS, BET, carbon monoxide chemisorption, and the catalytic performance was tested for hydrodeoxygenation (HDO) of methyl palmitate in a fixed-bed reactor. Interestingly, microwave irradiation does not result in sintering of Ni2P particles. The principal products of the HDO reaction for both catalysts are pentadecane and hexadecane. Isomerization products were not detected, and other by-products content is very low (1%). The HDO results demonstrate that the catalyst prepared using a microwave has better activity than that prepared using calcination.
- Xue, Yinan,Guan, Qingxin,Li, Wei
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p. 53623 - 53628
(2015/06/30)
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- Catalytic deoxygenation of fatty acids: Elucidation of the inhibition process
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Catalytic deoxygenation of unsaturated fatty acids in the absence of H2 is known to suffer from significant catalyst inhibition. Thus far, no conclusive results have been reported on the cause of deactivation. Here we show that C-C double bonds present in the feed or the products dramatically reduce the deoxygenation activity of supported palladium catalysts. In the case of stearic acid deoxygenation the addition of 0.1 equivalents of a mono-unsaturated fatty acid or olefin already reduces the catalytic deoxygenation activity by 60%. This effect becomes more pronounced with an increasing number of double bonds. The inhibition is shown to be reversible in H2 atmosphere, indicating no significant contribution from irreversibly deposited hard coke. Furthermore, the type of support material has no apparent effect on catalyst inhibition. Hence we propose that initial catalyst inhibition proceeds through reversible adsorption of C-C double bonds on the palladium active sites.
- Hollak, Stefan A. W.,De Jong, Krijn P.,Van Es, Daan S.
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p. 2648 - 2655
(2015/04/14)
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- Hydrodeoxygenation of methyl palmitate over sulfided Mo/Al 2O3, CoMo/Al2O3 and NiMo/Al 2O3 catalysts
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The catalytic properties of sulfided Mo/Al2O3, CoMo/Al2O3 and NiMo/Al2O3 catalysts in the hydrodeoxygenation of methyl palmitate as a model compound for triglyceride feedstock were studied at 300°C and 3.5 MPa in the batch reactor using n-tetradecane, m-xylene and hydrotreated straight-run gas oil (HT-SRGO). The comparison of catalyst's performance in n-tetradecane allowed us to see that the sulfided Mo/Al2O3, CoMo/Al 2O3 and NiMo/Al2O3 catalysts revealed the same rate of the methyl palmitate conversion but the rate of the intermediate oxygenates conversion decreased in order: CoMoS/Al 2O3 > NiMoS/Al2O3 > MoS 2/Al2O3. A mixture of linear saturated and unsaturated C15 and C16 hydrocarbons was produced when the oxygenates were fully consumed. The main products obtained over the Mo/Al 2O3 and CoMo/Al2O3 catalysts were C16 hydrocarbons (C16/C15-16.1 and 2.79, respectively); however, C15 hydrocarbons were preferentially formed over the NiMo/Al2O3 catalyst (C16/C 15-0.65), highlighting the different contributions of the hydrodeoxygenation (HDO) and decarboxylation/decarbonylation (DeCOx) pathways during the hydroconversion of methyl palmitate over these catalysts. Investigating the solvent's influence on the activity of the CoMo/Al 2O3 and NiMo/Al2O3 catalysts in the methyl palmitate HDO revealed that the reaction rate was decreased in the following order: n-tetradecane > HT-SRGO > m-xylene. The aromatic compounds did not retard the methyl palmitate transformation, but inhibited the conversion of the intermediate oxygenates. Decreased C16/C 15 ratios were observed over both catalysts when m-xylene was used as the reaction medium instead of n-tetradecane.
- Deliy, Irina V.,Vlasova, Evgenia N.,Nuzhdin, Alexey L.,Gerasimov, Evgeny Yu.,Bukhtiyarova, Galina A.
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p. 2242 - 2250
(2014/01/06)
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- Decarboxylation and further transformation of oleic acid over bifunctional, Pt/SAPO-11 catalyst and Pt/chloride Al2O3 catalysts
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Catalytic decarboxylation and further conversion of oleic acid to branched and aromatic hydrocarbons in a single process step, over Pt-SAPO-11 and Pt/chloride Al2O3 is presented. An increase of both reaction time and temperature increase the selectivity to heptadecane. Higher selectivity to heptadecane was observed in the presence of hydrogen. Decarboxylation of oleic acid was as high as ～98 wt% (selectivity for heptadecane >30%) at 325 C in the presence of hydrogen. Branched isomers, alkyl aromatics, like dodecyl benzene and cracked (17) paraffins were the other products.
- Ahmadi, Masoudeh,Macias, Eugenia E.,Jasinski, Jacek B.,Ratnasamy, Paul,Carreon, Moises A.
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- Manipulating catalytic pathways: Deoxygenation of palmitic acid on multifunctional catalysts
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The mechanism of the catalytic reduction of palmitic acid to n-pentadecane at 260 °C in the presence of hydrogen over catalysts combining multiple functions has been explored. The reaction involves rate-determining reduction of the carboxylic group of palmitic acid to give hexadecanal, which is catalyzed either solely by Ni or synergistically by Ni and the ZrO2 support. The latter route involves adsorption of the carboxylic acid group at an oxygen vacancy of ZrO2 and abstraction of the α-H with elimination of O to produce the ketene, which is in turn hydrogenated to the aldehyde over Ni sites. The aldehyde is subsequently decarbonylated to n-pentadecane on Ni. The rate of deoxygenation of palmitic acid is higher on Ni/ZrO2 than that on Ni/SiO2 or Ni/Al2O3, but is slower than that on H-zeolite-supported Ni. As the partial pressure of H2 is decreased, the overall deoxygenation rate decreases. In the absence of H 2, ketonization catalyzed by ZrO2 is the dominant reaction. Pd/C favors direct decarboxylation (-CO2), while Pt/C and Raney Ni catalyze the direct decarbonylation pathway (-CO). The rate of deoxygenation of palmitic acid (in units of mmol moltotal metal -1 h-1) decreases in the sequence r (Pt black)≈r(Pd black)>r(Raney Ni) in the absence of H2. In situ IR spectroscopy unequivocally shows the presence of adsorbed ketene (Ci?￡34;Ci?￡34;O) on the surface of ZrO2 during the reaction with palmitic acid at 260 °C in the presence or absence of H2. Biomass to biofuels: The conversion of palmitic acid to n-pentadecane over ZrO2 mainly proceeds by hydrogenation of the carboxylic acid group to give hexadecanal (rate-determining step), which is catalyzed either solely by Ni sites or synergistically by Ni sites and sites on the ZrO2 support (see scheme). In the absence of H2, ketonization is the dominant reaction catalyzed by ZrO 2. Copyright
- Peng, Baoxiang,Zhao, Chen,Kasakov, Stanislav,Foraita, Sebastian,Lercher, Johannes A.
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p. 4732 - 4741
(2013/05/22)
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- COMPOUNDS AND METHODS FOR THE PRODUCTION OF LONG CHAIN HYDROCARBONS FROM BIOLOGICAL SOURCES
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The present invention is directed to the preparation of oxygenated, unsaturated hydrocarbon compounds, such as derivatives of furfural or hydroxymethyl furfural produced by aldol condensation with a ketone or a ketoester, as well as methods of deoxidatively reducing those compounds with hydrogen under acidic conditions to provide saturated hydrocarbons useful as fuels.
- -
-
Paragraph 0093
(2013/03/28)
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- The hydrodeoxygenation of bioderived furans into alkanes
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The conversion of biomass into fuels and chemical feedstocks is one part of a drive to reduce the world's dependence on crude oil. For transportation fuels in particular, wholesale replacement of a fuel is logistically problematic, not least because of the infrastructure that is already in place. Here, we describe the catalytic defunctionalization of a series of biomass-derived molecules to provide linear alkanes suitable for use as transportation fuels. These biomass-derived molecules contain a variety of functional groups, including olefins, furan rings and carbonyl groups. We describe the removal of these in either a stepwise process or a one-pot process using common reagents and catalysts under mild reaction conditions to provide n-alkanes in good yields and with high selectivities. Our general synthetic approach is applicable to a range of precursors with different carbon content (chain length). This allows the selective generation of linear alkanes with carbon chain lengths between eight and sixteen carbons.
- Sutton, Andrew D.,Waldie, Fraser D.,Wu, Ruilian,Schlaf, Marcel,'Pete'Silks, Louis A.,Gordon, John C.
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p. 428 - 432
(2013/07/05)
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- Chloroform as a hydrogen atom donor in barton reductive decarboxylation reactions
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The utility of chloroform as both a solvent and a hydrogen atom donor in Barton reductive decarboxylation of a range of carboxylic acids was recently demonstrated (Ko, E. J. et al. Org. Lett. 2011, 13, 1944). In the present work, a combination of electronic structure calculations, direct dynamics calculations, and experimental studies was carried out to investigate how chloroform acts as a hydrogen atom donor in Barton reductive decarboxylations and to determine the scope of this process. The results from this study show that hydrogen atom transfer from chloroform occurs directly under kinetic control and is aided by a combination of polar effects and quantum mechanical tunneling. Chloroform acts as an effective hydrogen atom donor for primary, secondary, and tertiary alkyl radicals, although significant chlorination was also observed with unstrained tertiary carboxylic acids.
- Ho, Junming,Zheng, Jingjing,Meana-Paneda, Ruben,Truhlar, Donald G.,Ko, Eun Jung,Savage, G. Paul,Williams, Craig M.,Coote, Michelle L.,Tsanaktsidis, John
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p. 6677 - 6687
(2013/07/26)
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- Silver-catalyzed decarboxylative fluorination of aliphatic carboxylic acids in aqueous solution
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Although fluorinated compounds have found widespread applications in the chemical and materials industries, general and site-specific C(sp3)-F bond formations are still a challenging task. We report here that with the catalysis of AgNO3, various aliphatic carboxylic acids undergo efficient decarboxylative fluorination with SELECTFLUOR reagent in aqueous solution, leading to the synthesis of the corresponding alkyl fluorides in satisfactory yields under mild conditions. This radical fluorination method is not only efficient and general but also chemoselective and functional-group- compatible, thus making it highly practical in the synthesis of fluorinated molecules. A mechanism involvinig Ag(III)-mediated single electron transfer followed by fluorine atom transfer is proposed for this catalytic fluorodecarboxylation.
- Yin, Feng,Wang, Zhentao,Li, Zhaodong,Li, Chaozhong
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supporting information; experimental part
p. 10401 - 10404
(2012/08/08)
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- DEOXYGENATION OF FATTY ACIDS FOR PREPARATION OF HYDROCARBONS
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Embodiments of methods for making renewable diesel by deoxygenating fatty acids to produce hydrocarbons are disclosed. Fatty acids are exposed to a catalyst selected from a) M1 /M2 /M3O2 where M1 is a transition metal, a transition metal oxide, or a combination thereof, wherein the transition metal is Fe, Mn, Mo, V, or W, M2 is Pt, PtO, PtO2, or a combination thereof, and M3 is Ti or Zr, or b) Pt/Ge or Pt/Sn on carbon, and the catalyst decarboxylates at least 10% of the fatty acids. Deoxygenation is performed without added hydrogen and at less than 100 psi. Disclosed embodiments of the catalysts deoxygenate at least 10% of fatty acids in a fatty acid feed, and remain capable of deoxygenating fatty acids for at least 200 minutes to more than 350 hours.
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Page/Page column 36; 39
(2012/02/15)
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- Molybdenum carbide-catalyzed conversion of renewable oils into diesel-like hydrocarbons
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In the paper, we report for the first time that the conversion of renewable oils into diesel-like hydrocarbon mixtures can be realized on molybdenum carbides with high activity and selectivity. The molybdenum carbide catalyst exhibited much better resistance to leaching than noble metals and could be reused consecutively for sixteen times without deactivation. Mechanism investigations indicated that molybdenum carbide and palladium showed different reaction selectivities and it was speculated that the level of difficulty in acyl-to-alkyl rearrangement of surface acyl intermediates on molybdenum carbide and palladium resulted in the different product selectivity. Copyright
- Han, Junxing,Duan, Jinzhao,Chen, Ping,Lou, Hui,Zheng, Xiaoming
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experimental part
p. 2577 - 2583
(2011/12/01)
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- Differentiating C-Br and C-Cl bond activation by using solvent polarity: Applications to orthogonal alkyl-alkyl negishi reactions
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A pot to share: A Calkyl-Cl bond can be rendered "dormant" or "active" in the Negishi alkyl-alkyl cross-coupling by a simple solvent polarity "switch" (see scheme). Adjustment from a 1:2 to a 2:1 solvent ratio of dimethylimidazolidinone: tetrahydrofuran enables orthogonal alkyl-alkyl Negishi cross-coupling strategies to be carried out on bifunctional bromochloroalkanes in one pot at room temperature.
- Hadei, Niloufar,Achonduh, George T.,Valente, Cory,O'Brien, Christopher J.,Organ, Michael G.
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supporting information; experimental part
p. 3896 - 3899
(2011/06/24)
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- Facile regio- and stereoselective hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition metal complexes: Selective hydrogenation of alkynes with formic acid
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A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt3)4 (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt 3)4, but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Bronsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.
- Shen, Ruwei,Chen, Tieqiao,Zhao, Yalei,Qiu, Renhua,Zhou, Yongbo,Yin, Shuangfeng,Wang, Xiangbo,Goto, Midori,Han, Li-Biao
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supporting information; experimental part
p. 17037 - 17044
(2011/12/04)
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- Reducing the cost, smell, and toxicity of the Barton reductive decarboxylation: Chloroform as the hydrogen atom source
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When used as solvent, chloroform was found to act as a hydrogen atom donor in Barton reductive decarboxylation reactions. Chloroform offers a substantial practical advantage over pre-existing hydrogen atom donors.
- Ko, Eun Jung,Williams, Craig M.,Savage, G. Paul,Tsanaktsidis, John
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supporting information
p. 1944 - 1947
(2015/02/18)
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- Hydrothermal decarboxylation and hydrogenation of fatty acids over Pt/C
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We report herein on the conversion of saturated and unsaturated fatty acids to alkanes over Pt/C in high-temperature water. The reactions were done with no added H2. The saturated fatty acids (stearic, palmitic, and lauric acid) gave the corresponding decarboxylation products (n-alkanes) with greater than 90% selectivity, and the formation rates were independent of the fatty acid carbon number. The unsaturated fatty acids (oleic and linoleic acid) exhibited low selectivities to the decarboxylation product. Rather, the main pathway was hydrogenation to from stearic acid, the corresponding saturated fatty acid. This compound then underwent decarboxylation to form heptadecane. On the basis of these results, it appears that this reaction system promotes in situ H 2 formation. This hydrothermal decarboxylation route represents a new path for using renewable resources to make molecules with value as liquid transportation fuels.
- Fu, Jie,Lu, Xiuyang,Savage, Phillip E.
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experimental part
p. 481 - 486
(2012/02/14)
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- Hydrocarbon production from decarboxylation of fatty acid without hydrogen
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Decarboxylation of oleic acid without hydrogen was carried out using hydrotalcites with three different MgO contents (30, 63 and 70 wt%). Effect of MgO content in hydrotalcites and reaction temperatures on the decarboxylation performance in terms of oleic
- Na, Jeong-Geol,Yi, Bo Eun,Kim, Ju Nam,Yi, Kwang Bok,Park, Sung-Youl,Park, Jong-Ho,Kim, Jong-Nam,Ko, Chang Hyun
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experimental part
p. 44 - 48
(2010/12/25)
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- Efficient heterogeneous dual catalyst systems for alkane metathesis
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A fully heterogeneous and highly efficient dual catalyst system for alkane metathesis (AM) has been developed. The system is comprised of an alumina-supported iridium pincer catalyst for alkane dehydrogenation/olefin hydrogenation and a second heterogeneous olefin metathesis catalyst. The iridium catalysts bear basic functional groups on the aromatic backbone of the pincer ligand and are strongly adsorbed on Lewis acid sites on alumina. The heterogeneous systems exhibit higher lifetimes and productivities relative to the corresponding homogeneous systems as catalyst/catalyst interactions and bimolecular decomposition reactions are inhibited. Additionally, using a two-pot device, the supported Ir catalysts and metathesis catalysts can be physically separated and run at different temperatures. This system with isolated catalysts shows very high turnover numbers and is selective for the formation of high molecular weight alkanes.
- Huang, Zheng,Rolfe, Eleanor,Carson, Emily C.,Brookhart, Maurice,Goldman, Alan S,El-Khalafy, Sahar H.,Roy MacArthur, Amy H.
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experimental part
p. 125 - 135
(2010/06/20)
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