• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1597-1605
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• 2014

Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.386-392
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• 1991

Whole cells of Methylosinus trichosporium OB3b, the obligate methylotroph, were used to produce propylene oxide from propane. This strain has methane monooxygenase, which catalyzes the conversion methane to methanol and can catalyze also the conversion propane to propylene oxide. Optimal condition for the production of propylene oxide was investigated in resting-whole cell system. The optimal pH and temperature was 7.0 and $35^{\circ}C$ respectively. The end product, propylene oxide, didn't inhibit the production of propylene oxide and was not further metabolized in reaction mixture. The addition of methane metabolites (methanol, formaldehde and formic acid) to the reaction mixture stimulated formation of propylene oxide by $3{\sim}4$ times, and methanol was the most effective especially. Under the optimal conditions, the 14.2 mM of propylene oxide was produced after incubation of 60 min. and the conversion ratio of propane to propylene oxide was approximately 8%.

• Clean Technology
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• v.22 no.3
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• pp.196-202
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• 2016

In this study, ceria- based catalysts were prepared for dimethyl carbonate (DMC) synthesis and reaction conditions were evaluated for finding the optimal reaction route. In order to find optimal catalysts for DMC synthesis, calcination temperature and Cu(II) impregnation amount were evaluated. The oxidative carbonylation using methanol, carbon monoxide and oxygen and the direct synthesis using methanol and carbon dioxide were introduced for producing DMC. Following the law of Le Chatelier, the dehydration reaction was applied for enhancing the reactivity (methanol conversion) as removing water during the reaction. 2-cyanopyridine, as a chemical dehydration agent, was used. In the case of the oxidative carbonylation, methanol conversion rate increased from 15.1% to 38.7% and the DMC selectivity increased from 0% to 98.8%. In the case of the direct synthesis, methanol conversion rate increased from 1.0% to 77.8% and the DMC selectivity increased from 41.2% to 100.0%.

• Journal of the Korean Applied Science and Technology
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• v.23 no.3
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• pp.223-229
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• 2006

Methanol and formaldehyde were produced directly by the partial oxidation of methane over mixed oxide catalysts. The catalysts were composed of Mo and Bi with late-transition metals, such as Mn, Fe, and Co. The reaction was carried out at $450^{\circ}C$, 50 bar in a fixed-bed differential reactor. The prepared catalysts were characterized by $O_2-TPD$ and BET apparatus. Among the catalysts used, the catalyst composed of 1:1:2.5 molar ratio of Mo:Bi:Mn showed the best methane conversion and methanol selectivity. The change in ratio of methane to oxygen affected at the conversion and selectivity, and the most proper ratio was 10:1.5. Methane conversion, methanol and formaldehyde selectivities increased with the surface areas of the catalysts. From the $O_2-TPD$ result, it was found that the oxygen species responsible for this reaction might be the lattice oxygen species desorbed at high temperature around $800^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.93-103
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• 2006

Biogas is a byproduct after anaerobic digestion of organic materials and has been used as an energy source for heating and generating electricity. Demands of methanol for fuel mixed with gasoline and reactant in biodiesel production are steadily being increased. In this review, we summarized recent advancements in direct partial oxidation of methane to methanol with the brief history of methanol synthesis. The steam reforming and the catalytic oxidation of methane to methanol were compared, the former of which are mainly used in industrial scale and the latter in a stage of research and development. On the basis of this review, the possibility of methanol conversion from biogas was proposed in the aspects of the technological feasibility and the economical practicability.

• KSBB Journal
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• v.13 no.4
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• pp.391-398
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• 1998

The effect of culture medium copper availability on the specific growth rate(${\mu}$) and carbon conversion efficiency (CCE) was sutided for an obligatory methanotroph Methylosinus trichosporium OB3b under various combinations of carbon and nitrogen sources. Methane or methanol was used as a carbon source, and nitrate or ammonium was used as a nitrogen source. Medium copper availability determined the intracellular location or kind of methane monooxygenase (MMO), cell-membrane (particulate or pMMO) when copper was present and cytoplasm (soluble or sMMO) when copper was deficient. When methane was used as a carbon source, copper-containing medium exhibited higher ${\mu}$ and CCE than copper-free medium regardless of the kind of nitrogen source. When methanol was used as a carbon source, however, the effect of copper disappeared. Ammonium gave the higher ${\mu}$ and CCE than nitrate for both methane and methanol. Those observation suggest that there exist an important difference in energy utilization efficiency for methane assimilation between sMMO and pMMO.

• Korean Journal of Materials Research
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• v.9 no.8
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• pp.798-803
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• 1999

This study has been focused on the influence of Fe(III) incorporation into framework of SAPO-34(FeAPSO-34s;/su/Fe = 40,20 and 5) on the catalytic performance of methanol conversion. By rapid crystallization method, the XRD,SEM,ICP,TG-DTA, and BET sufrace areas. With an increase in the Fe content incorporated to the framework, the crystallinity identified from the intensity of XRD peaks slightly decreased and the particle size observed from SEM photographs decreased also. On the other hand, the acid sites in crystal decreased kin the Fe-incorporated samples, and the selectivity to ethylene for FeAPSO-34 catalyst on methanol conversion was enhanced compared with the nonmetal incorporated(SAPO-34)

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.283-290
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• 2004

The single-step process for conversion of syngas to DME give higher conversion than the syngas-to-methanol process. This arises because of a synergy among the three simultaneous reaction, methanol synthesis, methanol dehydration and water gas shift reaction, in the process. we would find the optimal condition of the process which these advantages. The optimal condition of DME synthesis reaction over a commercial $Cu/Zn/Al_2O_3$ catalyst and Hybrid catalyst in a fixed bed reactor. The syngas-to-dimethyl ether conversion was examined on various reaction condition (Temperature 473~553K, $H_2/CO$ ratio 1~3, Pressure 30'50atm, GHSV 1000~4000).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.493-498
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• 2004

The complex permittivities of methanol measured from 0.2 to 2.0 ㎓ using an open-ended coaxial probe revealed the large deviation from the given data in literature. In this paper, it was investigated whether the given or measured complex permittivity is similar to the real value of our methanol used for experiment. The FDTD method was applied to confirm the effect of our conversion model excluding the effect of sufficiently small measurement error. The complex permittivities reconverted from the computed reflection coefficient by employing our improved conversion model were not similar to the given value but measured value. These results assured the accuracy and stability of our measurement-and-conversion process.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.181-188
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• 2013

The effect of transition metal ion exchange into UZM-9 zeolite with LTA framework on its deactivation in methanol-to-olefin (MTO) conversion was discussed. The ion exchange of copper, cobalt, nickel, and iron did not induce any notable change in the crystallinity, crystal morphology, and acidity of UZM-9. The small cage entrance of UZM-9 caused the high selectivity to lower olefins in the MTO conversion, while its large cages allowed the rapid further cyclecondensation of active intermediates, polymethylbenzenes including hexamethylbenzene, resulting in a rapid deactivation. The UZM-9 containing copper and cobalt ions showed considerably slow deactivations. The interaction between transition metal ions and polymethylbenzene cation radicals, the active intermediates, generated in the MTO conversion stabilized the radicals and slowed down the deactivation of UZM-9.