The mechanism of selective oxidation of methane with hydrogen peroxide was studied for an H4PV1MO11O40 catalyst precursor, which has been reported to be the most active among various Keggin-type heteropolyacids and vanadium complexes in trifluoroacetic acid anhydride. The conversion vs. selectivity relationships, product reactivities with methane comparisons, and kinetic results all show that the first step, selective oxidation of methane into methanol or methyl trifluoroacetate, is rate-determining.
The addition of a radical scavenger significantly suppressed the oxidation, chlorocyclohexane was formed by the oxidation of cyclohexane in the presence of carbon tetrachloride, and the epoxidation of cis-stilbene proceeded without retaining the stereochemistry all indicate that the reaction includes a radical path. UV-vis data revealed that monoperoxomonovanadate is an active species, promoting the selective oxidation of methane to methanol or methyl trifluoroacetate.
Chemical Reactivity Between Methane with Hydrogen
Methane is used as a fuel in ovens, homes, water heaters, kilns, automobiles, turbines, and other applications. Methane is stored using activated carbon. When combined with liquid oxygen, refined liquid methane is used as rocket fuel in the BE-4 and Raptor engines.
Methane, as a major component of natural gas, is important for generating electricity by using it as a fuel in a gas turbine or steam generator. Methane emits less carbon dioxide per unit of heat released than other hydrocarbon fuels. Methane has the lowest heat of combustion of any hydrocarbon, at approximately 891 kJ/mol.
It does, however, produce more heat per mass (55.7 kJ/g) than any other organic molecule due to its relatively high hydrogen content, which accounts for 55% of the heat of combustion but only 25% of the molecular mass of methane. Methane is piped into homes in many cities for domestic heating and cooking. In this context, it is commonly referred to as natural gas, which has an energy content of 39 megajoules per cubic metre, or 1,000 BTU per standard cubic foot. Liquefied natural gas (LNG) is primarily methane (CH4) that has been converted into a liquid form for ease of storage or transportation.
Methane, as a liquid rocket fuel, has the advantage of producing smaller exhaust molecules than kerosene. This deposits less soot on the internal parts of rocket motors, making booster re-use easier. The lower the molecular weight of the exhaust, the greater the fraction of heat energy in the form of kinetic energy available for propulsion, and thus the greater the specific impulse of the rocket. The temperature range of liquid methane (91–112 K) is also nearly compatible with that of liquid oxygen (54–90 K).
Chlorination of Methane
When a methane and chlorine mixture is exposed to a flame, it explodes, releasing carbon and hydrogen chloride. This is an ineffective reaction! The reaction we’ll look at is a gentler one between methane and chlorine in the presence of ultraviolet light, which is typically sunlight. This is a good example of a photochemical reaction, which is one caused by light.
CH4 + Cl2 → CH3Cl + HCl
Chloromethane is an organic product. This is a substitution reaction because one of the hydrogen atoms in the methane has been replaced by a chlorine atom. The reaction, however, does not stop there, and all of the hydrogens in the methane can be replaced by chlorine atoms.
Chemical Properties of Methane
The Methane has a specific gravity of 0.554, making it lighter than air. In water, it is only slightly soluble. They burn quickly in air and emitting carbon dioxide and water vapour; the flame is pale, slightly luminous, and extremely hot. Methane has a boiling point of 162 °C (259.6 °F) and a melting point of 182.5 °C (296.5 °F). Methane is a very stable gas in general, but mixtures of methane and air with methane contents ranging from 5 to 14 percent by volume are explosive. Explosions of such mixtures have been common in coal mines and collieries, causing numerous mine disasters.
Uses of Methane
Methane is a significant source of hydrogen as well as some organic chemicals. At high temperatures, methane reacts with steam to produce carbon monoxide and hydrogen, the latter of which is used in the production of ammonia for fertilisers and explosives. Methanol, chloroform, carbon tetrachloride, and nitromethane are all valuable chemicals derived from methane. Incomplete methane combustion produces carbon black, which is widely used as a reinforcing agent in rubber used in automobile tyres.
Conclusion
Methane, as a liquid rocket fuel, has the advantage of producing smaller exhaust molecules than kerosene. The addition of a radical scavenger significantly suppressed the oxidation, chlorocyclohexane was formed by the oxidation of cyclohexane in the presence of carbon tetrachloride, and the epoxidation of cis-stilbene proceeded without retaining the stereochemistry all indicate that the reaction includes a radical path. Methane is used as a fuel in ovens, homes, water heaters, kilns, automobiles, turbines, and other applications. The lower the molecular weight of the exhaust, the greater the fraction of heat energy in the form of kinetic energy available for propulsion, and thus the greater the specific impulse of the rocket.