A Carbon Molecular Sieve-based Catalyst with Encapsulated Ruthenium Nanoparticles for Bio-oil Stabilization and Upgrading

Pyrolysis oil derived from biomass (bio-oil) is regarded as a potential substitute for petroleum crude for producing environmentally friendly fuels of the future. However, pyrolysis oil upgrading still remains an issue due to its complex composition, low stability, high oxygen and water contents, and low hydrogen-to-carbon ratio. Although hydrogenation was proposed as a promising technology to improve properties of pyrolysis oil, attempts to synthesize a selective and active hydrogenation catalyst have so far been unsuccessful. A major challenge is in obtaining bio-oils with stable composition that can be processed further to fuels in biorefineries. This work proposes a novel design for bio-oil stabilization catalyst with molecular sieve properties. This material consists of ruthenium nanoparticles encapsulated in an ultramicroporous carbon framework much like "berries-in-a-muffin". The hypothesis is that the most reactive bio-oil molecules (aldehydes and ketones below 5 Å that cause oligomerization) will be able to enter the pores and be hydrogenated by the ruthenium catalyst to non-reactive molecules, while other bio-oil components will not be able to access the pores and participate in chemical reactions on active sites. The stabilized bio-oil would then be ready for further hydroprocessing to produce fuels. Multistep synthesis of a carbon molecular sieve containing ruthenium nanoparticles was successfully accomplished. Transmission electron microscopy revealed that metal nanoparticles are less than 3 nm in diameter and uniformly distributed within catalyst pellets. Carbon dioxide adsorption at 273 K coupled with nitrogen adsorption at 77 K indicated that carbon porous structure is made up of ultramicropores with the total pore volume of 0.18 cm3/g and surface area of 646 m2/g. 75% of the pore volume consists of pores less than 8 Å. Adsorption of probe molecules measured by means of a tapered element oscillating microbalance (TEOM) confirmed that the catalyst possesses molecular sieve properties acting as a 5Å-molecular sieve. Slit-like pores of the carbon framework are accessible to bio-oil model compounds with minimum dimensions of 3.4-4.1 Å, such as furfural, acetaldehyde, acetone, and anisole. Water molecules as well as molecules of cyclohexanone and tetrahydrofuran (minimum dimension of 5.3 Å) are unable to adsorb on catalyst pores effectively. Estimated polarizabilities of model compounds confirm that the observed adsorption behavior is explained solely by the molecular sieve effect and does not follow from differences in interaction of the probe molecules with the carbon support. The observed catalyst pore cutoff size of 5 Å is shown to correspond to an estimated molecular size distribution in corn cob-derived bio-oil, allowing desired molecular size selectivity. This work suggests potential applications of a developed molecular sieve-based catalytic system including selective hydrogenation of light aldehydes and ketones involved in bio-oil stability issue, and selective reforming of low molecular weight oxygenates in bio-oil yielding in situ hydrogen

MODELING OF RUNNING CUTTERS FOR SHAPING OF IMPROVED NONINVOLUTE TOOTH GEARS

The questions of tooling design for production of advanced gears are considered. Engineering is based on the special applied development of the mathematical theory of multiparametric mappings of space. In fulfilled engineering of gear cutting tools for shaping of noninvolute gears it is provided for exclusion of distorted profiling after tool regrinds. There are proposed calculation algorithms, which may be used in dataware of respective CAD/CAM systems of maintenance for tooling backup. Among developed tools there are assembled shaping cutters with prismatic and round cutters. Compensatory possibilities of proposed assembled shaping cutters are ensured by repositioning of shaped cutting edges after their regrindings: by linear displacement of prismatic shaped cutters and angular displacement of round ones respectively

SOME GENERALIZATIONS AND REPRESENTATIONS OF THE POSSIBILITIES OF MULTI-PARAMETRIC MAPPING OF AFFIN SPACE IN AN APPENDIX TO THE CURVOLINEAR FORMING AND TRANSMISSION MOVEMENT

The works of Prof. B. A. Perepelitsa from Kharkov Polytechnic Institute and his disciples to develop an applied methodology of multiparameter mappings in relation to the profiling and functioning of complex curvilinear objects and transmission mechanisms in mechanical engineering, mainly with examples of gears, are presented. The completed review is gratefully devoted to the 10th anniversary of Fiability & Durability Journal, which has repeatedly provided its platform to the authors to highlight this development of the wide Romanian, European and world scientific community

Development of an Innovative Method for Combating Blood-Sucking Diptera insects

This article describes an innovative method for regulating populations of blood-sucking Diptera that parasitize cows. This relates to the field of agriculture, namely to the means of protecting farm animals from insect bites, and can be used to protect farm animals from ectoparasites during the period of their grazing. To produce these products, the polymer was treated with an impregnating solution containing pyrethroid (2-26% by weight of the untreated polymer product), an inhibitor of arthropod detoxification enzyme systems (0.5-20.0%), a lubricant (0.1-3.0%) and an aliphatic ketone (5-90%). The method was simple in execution, and the insecticidal acaricidal polymer products obtained according to the method had a long shelf life of at least seven months. The products were resistant to environmental influences and did not lead to environmental pollution with excess active substances. Keywords: Ear tags, s-fenvalerate, piperonyl butoxide, Dipter

ICEM2010-40186 MACROPOROUS CATALYSTS FOR HYDROTHERMAL OXIDATION OF METALLORGANIC COMPLEXES AT LIQUID RADIOACTIVE WASTE TREATMENT

ABSTRACT One of the main problems of liquid radioactive waste (LRW) management is concerned with treatment of decontamination waters containing organic ligands. The organic ligands like oxalic, citric and ethylenediaminetetraacetic acids form stable complexes with radionuclides which puts restrictions on application of many technologies of LRW management. One of the ways of destruction of metallorganic complexes consists in using the catalytic oxidation. However, the heterophase catalytic oxidation is rather problematic due to formation of metal oxides on the catalyst surface and calmatation of meso-and micropores. A possible solution of the above problem can be found in synthesis of macroporous catalysts for oxidation having a regular macroporous structure. The present paper describes the template synthesis of macroporous metalloxide catalysts performed with using siloxane-acrylate microemulsions as templates. The method for impregnation of precious metals (PM) particles into the template, which enables one to produce PM nanoparticles of a specific size and immobilize them in the porous structure of the synthesized metalloxide catalysts, is presented. A possible mechanism of the synthesis of macroporous catalysts is suggested and the comparison of the electronic and photoncorrelation spectroscopy results obtained at different stages of catalysts synthesis was conducted

Untangling complexities of selective carbon-oxygen bond activation using multiscale modeling and quantum theory development

Vlachos, Dionisios G.Selective carbon-oxygen bond activation in C2+ molecules represents an essential part of the carbon-neutral, solar energy-based economy of the future. In biomass-mediated pathways, the initial CO2 reduction and C-C coupling are carried out through biochemical photosynthesis in photoautotrophic organisms. The resulting chemicals and bioproducts are typically over-oxygenated. Subsequently, selective C-O bond scission in fatty acids, glucose, glycerol, and furans is conducted to remove some of the excess oxygen. Despite a plethora of proposed heterogeneous catalysts, the C-O activation mechanism and peculiarities of catalyst reactivity remain poorly understood. ☐ In this thesis, we report the discovery of a radical-mediated C-O bond activation mechanism on the multifunctional Ru/RuOx catalyst that enabled 2-methyl furan production from furfural with up to 76% yield at temperatures <200oC. To the best of our knowledge, this was the first evidence of a low-temperature radical reduction mechanism in heterogeneous catalysis. The breakthrough was made possible by extensive exploration of various catalytic site architectures and reaction mechanisms using density functional theory, together with microkinetic modeling that showed agreement with experiment in both ultrahigh vacuum and liquid phase, thus bridging the pressure gap. ☐ Through collaborative experimental/computational work, we show the mechanism generality by identifying a wide range of reducible oxides that can catalyze the C-O bond scission on vacancies. Moreover, we find reactivity trends for saturated vs. unsaturated compounds to be fully consistent with computational predictions regarding the positive effect of conjugation on C-O bond scission rates. ☐ We obtain computational evidence that a similar mechanism is at play on 3-4 nm PtCo nanocrystals, covered with a CoOx monolayer, and is responsible for ultrahigh yields (99%) of 2,5-dimethylfuran from 5-(hydroxymethyl)furfural. The catalyst structure and the reaction mechanism are fully consistent with EXAFS, XANES, XRD, TEM, chemisorption, and reactivity data. ☐ Advancements in mechanistic understanding were made possible by development of first principles microkinetic models, specifically designed to simulate experiments involving isotopically labeled species and to predict mass fragmentation patterns. Initial work led to the discovery of the ring-opening deuteration mechanism that shed light on the roles of substituent groups and of solvent on deuteration rates of furanics. The mechanism was in stark contrast to the commonly known Brønsted acid-catalyzed mechanism. ☐ Over the course of our studies, we encountered challenges associated with reliable reaction rate predictions on metal oxide catalysts, revealing deficiencies of current quantum mechanical methods. To address them, we propose a non-empirical quantum-theoretical framework, aimed to describe electronic structure of such materials more accurately. Remarkably, the rigorous quantum theoretical basis of the method makes it applicable also to molecules and metals, demonstrating a consistently improved description of chemical bonding across the chemical compound space. The newly developed method holds promise to make first principles predictions in catalysis, especially metal oxide catalysis, more reliable and at minimal extra computational cost.University of Delaware, Department of Chemical and Biomolecular EngineeringPh.D