Methanol converting methane

Spectroscopy of the PES for reactions of transition metal (M ) and metal oxide cations (MO ) is particularly interesting due to their rich and complex chemistry. Transition metal M+ can activate C—H bonds in hydrocarbons, including methane, and activate C—C bonds in alkanes [18-20] MO are excellent (and often selective) oxidants, capable of converting methane to methanol [21] and benzene to phenol [22-24]. Transition metal cations tend to be more reactive than the neutrals for two general reasons. First, most neutral transition metal atoms have a ground electronic state, and this... 

In 1990, Schroder and Schwarz reported that gas-phase FeO" " directly converts methane to methanol under thermal conditions [21]. The reaction is efficient, occuring at 20% of the collision rate, and is quite selective, producing methanol 40% of the time (FeOH+ + CH3 is the other major product). More recent experiments have shown that NiO and PtO also convert methane to methanol with good efficiency and selectivity [134]. Reactions of gas-phase transition metal oxides with methane thus provide a simple model system for the direct conversion of methane to methanol. These systems capture the essential chemistry, but do not have complicating contributions from solvent molecules, ligands, or multiple metal sites that are present in condensed-phase systems. 

DMO [Direct methane oxidation] A process for converting methane to methanol or synthetic liquid fuels. Under development by Catalytica in 1997. 

ICI Low Pressure Methanol A process for making methanol from methane and steam. The methanol is first converted to syngas by steam reforming at a relatively low pressure. The syngas is then converted to methanol over a copper-based catalyst ... 

This cycle, often referred to as the Shilov-cycle converts methane into methanol and chloromethane in homogeneous aqueous solution at mild temperatures of 100-120 °C (11). However, while Pt(II) (added to the reaction as PtCl ) serves as the catalyst, the system also requires Pt(IV) (in the form of PtCle-) as a stoichiometric oxidant. Clearly, this system impressively demonstrates functionalization of methane under mild homogeneous conditions, but is impractical due to the high cost of the stoichiometric oxidant used. A recent development by Catalytica Advanced Technology Inc., often referred to as the Catalytica system used platinum(II) complexes as catalysts to convert methane into methyl-bisulfate (12). The stoichiometric oxidant in this case is S03, dissolved in concentrated H2S04 solvent. This cycle is depicted in Scheme 3. 

In the 1980s, the oxidative coupling of methane to give ethylene and ethane was reported by Keller and Bhasin (8), whose discovery prompted numerous attempts to convert methane directly—and not only to ethylene and ethane (8), but also to methanol and formaldehyde (9) (Table I). Research on oxidative coupling of methane was motivated by results showing that the methane was... 

Methane to Methanol and/or Formaldehyde Recent research indicates that a catalyst system in the presence of H2SO4 can convert methane directly into methanol. Homogeneous catalyst systems show promise. Also, heterogeneous Fe-ZSM-5 catalysts are reported to be attractive for this chemistry. Novel plasma reactors to generate hydroxyl radicals are also being investigated. 

The multiprotein complex methane monooxygenase (MMO) serves meth-anotrophs to convert methane to methanol. It can be either soluble (sMMO) or membrane bound ( particulate , pMMO) and it typically consists of three components, a reductase (MMOR), a component termed protein B (MMOB) and a hydroxylase denoted MMOH. The nature of the metal cofactors in the latter component are reasonably well understood for sMMO as will be discussed in the non-heme iron section. For the pMMO of Methylococcus capsulatus an obligate requirement for copper was shown. As reported in reference 1 a trinuclear Cu(II) cluster was discussed128 but the number and coordination of coppers still is a matter of continuing investigation since then. 

This study indicates the possibility of selectively converting methane into formaldehyde without first going to methanol. 

Whatever the source of synthesis gas, it is the starting point for many industrial chemicals. Some examples to be discussed are the hydroformylation process for converting alkenes to aldehydes and alcohols, the Monsanto process for the production of acetic acid from methanol, the synthesis of methanol from methane, and the preparation of gasoline by the Mobil and Fischer-Tropsch methods. 

The transformation was called an homologation reaction because essentially it consisted in going from one alcohol to an alcohol containing one carbon atom more than the starting material (Wender, Levine, and Orchin, 14). Tertiary alcohols reacted most rapidly, secondary alcohols less rapidly and primary alcohols only very slowly. It was of considerable importance to ascertain whether the olefin intermediate was essential and for this purpose, methanol and benzyl alcohol, neither of which can dehydrate to an olefin, were used in the reaction. Both compounds, contrary to other primary alcohols, reacted quite rapidly and gave the homologous alcohol of the methanol converted, about 40 mole per cent went to ethanol and with benzyl alcohol, a 30% yield of 2-phenylethanol was secured. In both examples, however, reduction products were also present of the methanol converted, 8 mole per cent went to methane and from benzyl alcohol, a 50 to 60% yield of toluene was secured. The conversion of methanol to methane appears to be the only case in which an appreciable quantity of hydrocarbon is secured from a purely aliphatic alcohol. The behavior of benzyl alcohol and its derivatives will be discussed later. 

One of your customers is a manufacturer of methanol. Her firm has several plants, with a huge production capacity. A methanol plant converts methane and water into methanol in two steps. In the first reformer reactor methane is converted into carbon monoxide and hydrogen (Figure 17-2). In the second synthesis reactor the carbon monoxide and part of... 

It is a mixed-function oxidase in which one atom of 02 is transferred to a substrate and the other forms water. The system converts methane to methanol in a process that is coupled to the oxidation of NADH, according to... 

To convert methane (see Fig. 1J), it is theoretically possible to adjust the oxygen content to obtain an effluent in which the H2/CO ratio is dose to 2. In practicC it is necessary to consider the losses resulting from the formation of methane during the synthesis of methanol, and aim for an H2/CO ratio of aroiod 2.25, which is ideal for this conversion. 

A two-step-reaction sequence describes the methanol synthesis. In the first step, steam reforming, a packed bed reactor (reformer) converts methane into a mixture of hydrogen and carbon monoxide (synthesis gas), according to Equation 3.5.1. Then, in the second step, a second packed-bed reactor (converter) converts the synthesis gas into methanol, as shown by Equation 3.5.2. 

Reduced cation oxidation states can drive reduction reactions of oxygenated adsorbates. Sputter-reduced surfaces of TiO2(001) readily converted formic acid into formaldehyde and methanol into methane and CO. 

The process objective can be described most simply as converting methane and water into methanol and hydrogen, and then purifying the methanol so that it meets specifications. The overall process stoichiometry is given by the following relationship ... 

Methane monooxygencises (MMOs) aire a group of enzjrmes which convert methane to methanol via a monooxygenaise pathway in which the dioxygen molecule is activated [66, 67, 68]. The overall reciction is given... 

The stability of carbanions follows the opposite sequence to that of carbonium ions, i.e., carbanions at primary carbon atoms are more stable than those at secondary or tertiary carbon atoms [144]. Thus, one would expect that it might be possible to convert methane and ethane with methanol. Unfortunately activation and/or proton abstraction from alkanes seems not to be possible to a significant extent, as attempts to react methanol with methane or ethane have up till now failed. Presumably, one needs to couple such experiments with oxidative dehydrogenation [145] in order to achieve feasible conversions. 

This is one question that X-ray answers better than any other method what shape does a molecule have Another important problem it can solve is the structure of a new imknown compound. There are bacteria in oil wells, for example, that use methane as an energy source. It is amazing that bacteria manage to convert methane into anything useful, and, of course, chemists really wanted to know how they did it. Then in 1979 it was found that the bacteria use a coenzyme, given the trivial name methoxatin , to oxidize methane to methanol. Methoxatin was a new compoimd with an unknown structure and could be obtained in only very small amounts. It proved exceptionally difficult to solve the structure by NMR but eventually methoxatin was found by X-ray crystallography to be a polycyclic tricarboxylic acid. This is a more complex molecule than hexanedioic acid but X-ray crystallographers routinely solve much more complex structures than this. 

Oxidation-reduction reactions Many organic compounds can be converted to other compounds by oxidation and reduction reactions. For example, suppose that you wish to convert methane, the main constituent of natural gas, to methanol, a common industrial solvent and raw material for making formaldehyde and methyl esters. The conversion of methane to methanol may be represented by the following equation, in which [O] represents oxygen from an agent such as copper(II) oxide, potassium dichromate, or sulfuric acid. 

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