Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, often an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogenation reduces double and triple bonds in hydrocarbons.
The pyrolysis process is the thermal decomposition of materials at elevated temperatures in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements pyro "fire", "heat", "fever" and lysis "separating".
In organic chemistry, an epoxide is a cyclic ether with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile.
Dehydrogenation is the chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At its simplest, it is useful way of converting alkanes, which are relatively inert and thus low-valued, to olefins, which are reactive and thus more valuable. Alkenes are precursors to aldehydes, alcohols, polymers, and aromatics. As a problematic reaction, the fouling and inactivation of many catalysts arises via coking, which is the dehydrogenative polymerization of organic substrates.
The Sabatier reaction or Sabatier process produces methane and water from a reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst. It was discovered by the French chemists Paul Sabatier and Jean-Baptiste Senderens in 1897. Optionally, ruthenium on alumina makes a more efficient catalyst. It is described by the following exothermic reaction.
Wilkinson's catalyst is the common name for chloridotris(triphenylphosphine)rhodium(I), a coordination complex of rhodium with the formula [RhCl(PPh3)3] (Ph = phenyl). It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in tetrahydrofuran or chlorinated solvents such as dichloromethane. The compound is widely used as a catalyst for hydrogenation of alkenes. It is named after chemist and Nobel laureate Sir Geoffrey Wilkinson, who first popularized its use.
Rhodium(III) oxide (or Rhodium sesquioxide) is the inorganic compound with the formula Rh2O3. It is a gray solid that is insoluble in ordinary solvents.
Deoxygenation is a chemical reaction involving the removal of oxygen atoms from a molecule. The term also refers to the removal of molecular oxygen (O2) from gases and solvents, a step in air-free technique and gas purifiers. As applied to organic compounds, deoxygenation is a component of fuels production as well a type of reaction employed in organic synthesis, e.g. of pharmaceuticals.
γ-Valerolactone (GVL) is an organic compound with the formula C5H8O2. This colourless liquid is one of the more common lactones. GVL is chiral but is usually used as the racemate. It is readily obtained from cellulosic biomass and is a potential fuel and green solvent.
Carbonylation refers to reactions that introduce carbon monoxide into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbonylation also refers to oxidation of protein side chains.
Reactive flash volatilization (RFV) is a chemical process that rapidly converts nonvolatile solids and liquids to volatile compounds by thermal decomposition for integration with catalytic chemistries.
Catalytic oxidation are processes that rely on catalysts to introduce oxygen into organic and inorganic compounds. Many applications, including the focus of this article, involve oxidation by oxygen. Such processes are conducted on a large scale for the remediation of pollutants, production of valuable chemicals, and the production of energy.
The OxFA process is a process to produce formic acid from biomass by catalytic oxidation using molecular oxygen or air. Polyoxometalates of the Keggin-type are used as catalysts.
Hydrodenitrogenation (HDN) is an industrial process for the removal of nitrogen from petroleum. Organonitrogen compounds, even though they occur at low levels, are undesirable because they cause poisoning of downstream catalysts. Furthermore, upon combustion, organonitrogen compounds generate NOx, a pollutant. HDN is effected as general hydroprocessing, which traditionally focuses on hydrodesulfurization (HDS) because sulfur compounds are even more problematic. To some extent, hydrodeoxygenation (HDO) is also effected.
Renewable hydrocarbon fuels via decarboxylation/decarbonylation. With an increasing demand for renewable fuels, extensive research is under way on the utilization of biomass as feedstock for the production of liquid transportation fuels. Using biomass is an attractive alternative, since biomass removes carbon dioxide from the atmosphere as it grows through photosynthesis, thus closing the carbon cycle and making biofuels carbon neutral when certain conditions are met. First generation biofuels such as biodiesel have important drawbacks, as they are normally derived from edible feedstock and are not fully compatible with standard diesel engines. Given that the majority of the problems associated with these fuels stem from their high oxygen content, methods to deoxygenate biomass-derived oils are currently being pursued. The ultimate goal is to convert inedible biomass feeds into hydrocarbon biofuels fully compatible with existing infrastructure. These so-called second generation biofuels can be used as drop-in substitutes for traditional petroleum-derived hydrocarbon fuels.
Mahdi Muhammad Abu-Omar is a Palestinian American chemist, currently the Duncan and Suzanne Mellichamp Professor of Green Chemistry in the Departments of Chemistry & Biochemistry and Chemical Engineering at University of California, Santa Barbara.
Clark Landis is an American chemist, whose research focuses on organic and inorganic chemistry. He is currently a Professor of Chemistry at the University of Wisconsin–Madison. He was awarded the ACS Award in Organometallic Chemistry in 2010, and is a fellow of the American Chemical Society and the American Association for the Advancement of Science.
Levoglucosenone is a bridged, unsaturated heterocyclic ketone formed from levoglucosan by loss of two molecules of water. It is the major component produced during the acid-catalysed pyrolysis of cellulose, D-glucose, and levoglucosan.
Dihydrolevoglucosenone (Cyrene) is a bicyclic, chiral, seven-membered heterocyclic cycloalkanone which is a waste derived and fully biodegradable aprotic dipolar solvent. It is a environmentally friendly alternative to dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP).
Hilkka Inkeri Kenttämaa is a researcher in organic and bioorganic mass spectrometry, and the Frank Brown Endowed Distinguished Professor of Chemistry at Purdue University. She is a pioneer in distonic radical cation research and laser-induced acoustic desorption.
