112-92-5Relevant articles and documents
Selective Hydrodeoxygenation of Vegetable Oils and Waste Cooking Oils to Green Diesel Using a Silica-Supported Ir–ReOx Bimetallic Catalyst
Liu, Sibao,Simonetti, Trent,Zheng, Weiqing,Saha, Basudeb
, p. 1446 - 1454 (2018)
High yields of diesel-range alkanes are prepared by hydrodeoxygenation of vegetable oils and waste cooking oils over ReOx-modified Ir/SiO2 catalysts under mild reaction conditions. The catalyst containing a Re/Ir molar ratio of 3 exhibits the best performance, achieving 79–85 wt % yield of diesel-range alkanes at 453 K and 2 MPa H2. The yield is nearly quantitative for the theoretical possible long-chain alkanes on the basis of weight of the converted oils. The catalyst retains comparable activity upon regeneration through calcination. Control experiments using probe molecules as model substrates suggest that C=C bonds of unsaturated triglycerides and free fatty acids are first hydrogenated to their corresponding saturated intermediates, which are then converted to aldehyde intermediates through hydrogenolysis of acyl C?O bonds and subsequently hydrogenated to fatty alcohols. Finally, long-chain alkanes without any carbon loss are formed by direct hydrogenolysis of the fatty alcohols. Small amounts of alkanes with one carbon fewer are also formed by decarbonylation of the aldehyde intermediates. A synergy between Ir and partially reduced ReOx sites is discussed to elucidate the high activity of Ir–ReOx/SiO2.
An unconventional DCOx favored Co/N-C catalyst for efficient conversion of fatty acids and esters to liquid alkanes
Li, Jiang,Liu, Jiaxing,Zhang, Junjie,Wan, Tong,Huang, Lei,Wang, Xintian,Pan, Runze,An, Zhidong,Vlachos, Dionisios G.
, (2020)
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.
Permeable composite membrane as a catalytically active contactor for hydrogenation reactions
Minyukova, T. P.,Shtertser, N. V.,Khassin, A. A.,Yurieva, T. M.
, p. 107 - 110,4 (2012)
The efficiency of using of the permeable composite membrane (PCM) is demonstrated in the 3-phase reaction of liquid substrate with gaseous hydrogen on solid catalyst (PCM acts as a catalytically active contactor) - hydrogenation of fatty acid triglyceride. PCM provides a good combination of the opposite requirements of mild internal diffusion restrictions, low hydraulic resistance, high thermal conductivity, well-developed gas-liquid interface and high catalyst loading in the reactor volume, and thus assures the control of the course of the catalytic reaction.
Highly Selective Hydrodecarbonylation of Oleic Acid into n-Heptadecane over a Supported Nickel/Zinc Oxide-Alumina Catalyst
Li, Guangci,Zhang, Feng,Chen, Lei,Zhang, Chuanhui,Huang, He,Li, Xuebing
, p. 2646 - 2653 (2015)
The production of second-generation biodiesel with triglycerides or their derivatives through hydroprocessing is considered as a promising approach to make transportation fuels. In this study, a series of Ni-based catalysts supported on basic composite oxides (MO-Al2O3, M=Mg, Ca, Ni, Cu, Zn) were prepared for the catalytic deoxygenation of oleic acid in the presence of H2. Ni/ZnO-Al2O3 exhibited the highest deoxygenation activity and alkane selectivity, which depended on its moderate basicity. Investigations of the reaction conditions, which include reaction time, reaction temperature, H2 pressure, and Ni loading, suggested that n-heptadecane was the predominant product and its content increased with reaction temperature. The reaction temperature was more important than H2 pressure in the catalytic deoxygenation of oleic acid. Additionally, the overall reaction pathways for the conversion of oleic acid were proposed based on the product distribution for different durations and reaction rates of stearic acid, 1-octadecanol, and stearyl stearate, in which the oxygen atoms in the oleic acid were mainly removed in the form of CO through a hydrogenation-dehydrogenation-decarbonylation reaction route. If glycerol trioleate was used instead of oleic acid, Ni/ZnO-Al2O3 exhibited a high hydrodecarbonylation activity and selectivity to n-heptadecane.
Influence of the operating conditions and kinetic analysis of the selective hydrogenation of oleic acid on Ru-Sn-B/Al2O3 catalysts
Sánchez, María A.,Pouilloux, Yannick,Mazzieri, Vanina A.,Pieck, Carlos L.
, p. 552 - 558 (2013)
The influence of the operating conditions on the selectivity and activity of Ru-Sn-B/Al2O3 catalysts for the hydrogenation of oleic acid to oleyl alcohol was studied. It was found that the Ru-Sn-B/Al 2O3 catalyst is selective to oleyl alcohol while Ru or Ru-B/Al2O3 catalysts are not selective to produce oleyl alcohol. The electronic and catalytic properties of Ru are modified by the strong interaction between Sn and B. The incorporation of Sn leads to catalysts capable of producing oleyl alcohol. The experiments of oleic acid hydrogenation showed that an increase in reaction temperature leads to an increase in activity while the selectivity to oleyl alcohol goes through a maximum. This is because the reactions of hydrogenation of CC double bond have lower activation energies than hydrogenolytic reactions. The increase in operating pressure has a positive effect on conversion and a more important effect on selectivity. A very simple first order kinetic model is proposed and reasonably represents the results obtained. This model can be useful to compare catalyst performance more rationally.
Synergistic Interaction between Oxides of Copper and Iron for Production of Fatty Alcohols from Fatty Acids
Kandel, Kapil,Chaudhary, Umesh,Nelson, Nicholas C.,Slowing, Igor I.
, p. 6719 - 6723 (2015)
The selective hydrogenation of fatty acids to fatty alcohols can be achieved under moderate conditions (180 °C, 30 bar H2) by simultaneously supporting copper and iron oxides on mesoporous silica nanoparticles. The activity of the cosupported oxides is significantly higher than that of each supported metal oxide and of a physical mixture of both individually supported metal oxides. A strong interaction between both metal oxides is evident from dispersion, XRD, TPR, and acetic acid TPD measurements, which is likely responsible for the synergistic behavior of the catalyst. Copper oxide is reduced in situ to its metallic form and thereby activates hydrogen. It is proposed that hydrogen spills over to iron oxide where fatty acids bind and are selectively reduced to the alcohol.
Kinetics of hydrodeoxygenation of stearic acid using supported nickel catalysts: Effects of supports
Kumar, Pankaj,Yenumala, Sudhakara Reddy,Maity, Sunil K.,Shee, Debaprasad
, p. 28 - 38 (2014)
The hydrodeoxygenation of fatty acids derived from vegetable and microalgal oils is a novel process for production of liquid hydrocarbon fuels well-suited with existing internal combustion engines. The hydrodeoxygenation of stearic acid was investigated in a high pressure batch reactor using n-dodecane as solvent over nickel metal catalysts supported on SiO2, γ-Al2O3, and HZSM-5 in the temperature range of 533-563 K. Several supported nickel oxide catalysts with nickel loading up to 25 wt.% were prepared by incipient wetness impregnation method and reduced using hydrogen. The catalysts were then characterized by BET, TPR, H2 pulse chemisorption, TPD, XRD, and ICP-AES. Characterization studies revealed that only dispersed nickel oxide was present up to 15 wt.% nickel loading on γ-Al2O3. The acidity of the supports depends on nickel loading of oxidized catalysts and increases with increasing nickel loading up to 15 wt.%. n-Pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and l-octadecanol were identified as products of hydrodeoxygenation of stearic acid with n-heptadecane being primary product. The catalytic activity and selectivity to products for hydrodeoxygenation of stearic acid depends strongly on acidity of the supports. The maximum selectivity to n-heptadecane was observed with nickel supported γ-Al2O3 catalyst. A suitable reaction mechanism of hydrodeoxygenation of stearic acid was delineated based on products distribution. The conversion of stearic acid was increased with increasing reaction time, nickel loading on γ-Al2O 3, temperature, and catalyst loading. Complete conversion of stearic acid was accomplished with more than 80% selectivity to n-heptadecane at reasonable reaction temperature of 563 K after 240 min of reaction using 15 wt.% Ni/γ-Al2O3 catalyst. An empirical kinetic model was also developed to correlate the experimental data.
The selective hydrogenation of ethyl stearate to stearyl alcohol over Cu/Fe bimetallic catalysts
He, Limin,Li, Xiaoru,Lin, Weiwei,Li, Wei,Cheng, Haiyang,Yu, Yancun,Fujita, Shin-Ichiro,Arai, Masahiko,Zhao, Fengyu
, p. 143 - 149 (2014)
Bimetallic and monometallic catalysts including Cu and/or Fe species were prepared by a co-precipitation method and their catalytic performance was tested for the selective hydrogenation of ethyl stearate to stearyl alcohol. The bimetallic catalysts were observed to be even more active for this selective hydrogenation compared to the monometallic catalysts and their physical mixtures. With a bimetallic catalyst of Cu/Fe (4/1 in mole ratio) reduced at 200 °C, a selectivity to the alcohol reached to above 99% at a conversion of 97% in reaction for 4 h at 230°C, 3.0 MPa. Effects of composition and reduction temperature on the catalytic performance were studied and the properties of catalysts prepared under different conditions were examined by XRD, TPR, N2 physisorption, and SEM. The relationship of the performance with the properties of the catalysts was discussed, along with the conditions under which synergistic effects of Cu and Fe species appeared and caused the enhancement of the catalytic performance.
An efficient hydrogenation catalytic model hosted in a stable hyper-crosslinked porous-organic-polymer: From fatty acid to bio-based alkane diesel synthesis
Sarkar, Chitra,Shit, Subhash Chandra,Dao, Duy Quang,Lee, Jihyeon,Tran, Ngoc Han,Singuru, Ramana,An, Kwangjin,Nguyen, Dang Nam,Le, Quyet Van,Amaniampong, Prince Nana,Drif, Asmaa,Jerome, Francois,Huyen, Pham Thanh,Phan, Thi To Nga,Vo, Dai-Viet N.,Thanh Binh, Nguyen,Trinh, Quang Thang,Sherburne, Matthew P.,Mondal, John
, p. 2049 - 2068 (2020)
In this study, a Pd-based catalytic model over a nitrogen enriched fibrous Porous-Organic-Polymer (POP) is established to execute hydrodeoxygenation of various vegetable oils in producing potential large-scale renewable diesel. Here we report a cost-effective synthesis strategy for a new microporous hypercrosslinked POP through the FeCl3 assisted Friedel-Crafts alkylation reaction, followed by fabrication of Pd0-NPs (2-3 nm) using a solid gas phase hydrogenation route to deliver a novel catalytic system. This catalyst (called Pd@PPN) exhibits versatile catalytic performance for different types of vegetable oils including palm oil, soybean oil, sunflower oil and rapeseed oil to furnish long chain diesel range alkanes. The catalyst is comprehensively characterized using various spectroscopic tools and it shows high stability during five runs of recycling without leaching of Pd. Our results further reveal that a direct decarbonylation (DCN) pathway of fatty acids to produce alkanes with one fewer carbon is the dominant mechanism. Under optimized conditions, using stearic acid to represent the long linear carboxylic acids in the vegetable oils, up to 90% conversion with 83% selectivity of C17-alkane has been achieved on our fabricated catalyst. Density functional theory (DFT) calculations are performed to provide insights into the electronic properties of the catalyst, the mechanistic reaction pathway, the crucial role of the catalyst surface and the product selectivity trend. The strong interaction between the corrugated polymer-frame-structure and the Pd-NPs suggests the presence of high density step sites on the fabricated Pd-NP anchored within the cage of the polymer structure. DFT calculations also reveal the strong promotional effect of step sites and charge transfer in facilitating rate-limiting steps during the decarbonylation (DCN) pathway and removal of strongly bound intermediates formed during the process, therefore explaining the high activity of the fabricated Pd@PPN catayst for the hydrodeoxygenation (HDO) conversion to produce bio-based alkane diesel.
Spectroscopy and Reactivity of Dialkoxy Acenes
Brega, Valentina,Kanari, Sare Nur,Doherty, Connor T.,Che, Dante,Sharber, Seth A.,Thomas, Samuel W.
, p. 10400 - 10407 (2019)
Photochemical oxidation of acenes can benefit or impede their function, depending on the application. Although acenes with alkoxy substituents on reactive sites are important for applications as diverse as drug delivery and organic optoelectronics, the influence of chemical structure on their photochemical oxidation remains unknown. This paper therefore describes the synthesis, spectroscopic properties, and reactivity with singlet oxygen (1O2) of a series of dialkoxyacenes that vary in the number and types of fused rings in the (hetero)acene cores. Reductive alkylation of quinone precursors yielded target dialkoxyacenes with fused backbones ranging from benzodithiophene to tetracenothiophene. Trends of their experimental spectroscopic characteristics were consistent with time-dependent density functional theory (TD-DFT) calculations. NMR studies show that photochemically generated 1O2 oxidizes all but one of these acenes to the corresponding endoperoxides in organic solvent. The rates of these oxidations correlate with the number and types of fused arenes, with longer dialkoxyacenes generally oxidizing faster than shorter derivatives. Finally, irradiation of these acenes in acidic, oxidizing environments cleaves the ether bonds. This work impacts those working in organic optoelectronics, as well as those interested in harnessing photogenerated reactive oxygen species in functional materials.
