Methanol, from methane

One possible route is to make formaldehyde direcdy from methane by partial oxidation. This process has been extensively studied (106—108). The incentive for such a process is reduction of raw material costs by avoiding the capital and expense of producing the methanol from methane. 

Zinc oxide has various uses but the most important is as co-catalyst with CuO supported on A1203 for low-pressure synthesis of methanol from methane.325... 

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 ... 

More recently, the direct synthesis of methanol from methane, using metallic gold as catalyst, was reported, involving a purported CH3-Au intermediate. Selenic acid was used as a stoichiometric oxidant as it is known to oxidize gold metal. Moderate turnovers (30) were achieved (Equation (6)).14... 

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. 

Note how the names of alcohols are obtained by replacing the final e of the name of the parent hydrocarbon by the suffix -ol. Thus, we get ethanol from ethane and methanol from methane. Alcohols can also be named by regarding the hydrocarbon chain as a group attached to the rest of the molecule. To name an alkane as a group, replace the ending by -yl, as in —CH3, methyl, and —CH2CH3, ethyl. Thus, CH,CH2OH is also called ethyl alcohol. 

We examine, as an example, the exergy vector diagram for methanol synthesis to estimate the minimum exergy loss thermodynamically required for the synthesis reaction of methanol from methane [Ref. 16.]. First, we consider a direct (single step) synthesis of methanol from methane through a coupled-and-coupling reaction consisting of the oxidation of methane (objective reaction) and the dissociation of water molecule (coupled reaction) shown, respectively, as follows ... 

Catalytica A catalytic process for making methanol from methane via methyl hydrogen sulfate. Both yield and selectivity are good, but the process requires the recycle of large quantities of sulfuric acid and so has proved uneconomic and has never been operated. The catalyst is a platinum compex. If a catalyst could be devised that would make the process a hundred times faster, the process might be economic. 

The methanotrophic bacteria have one known pathway for aerobic methane oxidation to CO2 31, 42,123). MMO catalyzes the first energetically difficult step in the formation of methanol from methane. The second step is catalyzed by methanol dehydrogenase (with a PQQ cofactor) and results in formation of formaldehyde, which is then converted by formaldehyde dehydrogenase (with no known cofactor) to formate. Finally, carbon dioxide is produced by formate dehydrogenase (with five different iron-sulfur clusters, a Mo-pterin cofactor, and an unusual flavin) 31, 42, 123). MMOs have a unique ability to oxidize a broad range 31,42,128,129) of hydrocarbons in addition to methane. One other system with a similar broad substrate utilization is the monoheme cytochrome P450 family, but in this case different isozymes show different specific activities (31). For soluble MMO, one single... 

Progress has also been achieved toward the direct oxidation of methane to acetic acid, for example, by Periana and coworkers, who used a Pd(II) catalyst in concentrated sulfuric acid at 180 °C [191-193]. The results of isotopic labeling experiments were consistent with a mechanism in which oxidation of methanol (from methane) generates a "CO" species that carbonylates a Pd-methyl species formed by C-H activation. 

A possible method for the production of methanol from methane is through chlorination to methyl chloride followed by hydrolysis to methanol. Because of the relative cheapness of the reactants, the chlorination of methane has been rather thoroughly studied. It has been shown that by the use of diluents for heat control, it is possible to control the chlorination to such a degree that preponderating proportions of any one of the chlorination products may be obtained 128 at will. 

Non-Thermal Plasma Direct Synthesis of Methanol from Methane and Carbon Dioxide... 

Similarly to the aforementioned reactions in the CH4-CO2 mixture, the reaction of methane and water vapor in thermal plasma leads to the production of syngas (H2, CO). Non-thermal plasma is also usually applied to produce the H2-CO mixture (see Chapter 10). As was demonstrated by Okazaki and Kishida (1999), application of non-thermal plasma permits the direct production of methanol from methane ... 

Methanotrophs are bacteria that grow using methane as their only food source. It may be possible to harness this capability and produce various chemicals (like methanol) from methane or to reduce the methane levels in the atmosphere. High levels of methane are believed to contribute to global warming. 

Olah and Prakash have reported a method of producing methanol from methane in a three-step system, in which formaldehyde is obtained initially in a quartz-mbe continuous-flow reactor. Formaldehyde is then transformed into formic acid on alkahne-earth oxides and finally methanol/formic acid is transformed into methanol methyl formate employing a WO3/AI2O3 catalyst. However, at the moment, only low yield to oxygenated products has been obtained. 

Beznis, N., Weekhuysen, B. and Bitter, J. (2010). Cu-ZSM-5 Zeolites for the Formation of Methanol from Methane and Oxygen Probing the Active Sites and Spectator Species, Catal. Lett., 138, pp. 14-22. 

Marrone, R, Cantwell, S. and Dalton, D. (2005). SCWO system designs for waste treatment Application to chemical weapons destruction, Ind. Eng. Chem. Res., 44, pp. 9030-9039. Brandvold, T. and Kocal, J. (2007). Process for the direct production of methanol from methane, US Patent 7288684 (UOP LLC). 

ICI Low-Pressure Methanol A process for making methanol from methane and steam. The methanol is... 

MeXTH [Methyl halides to Hydrocarbons] (X = Cl or Br) A general name for processes for converting methanol (from methane) to hydrocarbons via methyl halides. This has been proposed as an alternative to the MTO process, requiring less energy, but it has not yet been commercialized. An oxychlorination step is followed by reaction over a zeotype catalyst such as H-SAPO-34. 

Sergio R, Thornton JD. Synthesis of formaldehyde and methanol from methane and water in an electrical discharge two-phase reactor. J Appl Chem 1967 17 325—8. 

The production of syngas, used for the synthesis of methanol from methane, occurs via its partial oxidation (Eq. 19), steam reforming (Eq. 20) and CO2 reforming (Eq. 21), also called dry reforming ... 

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