Methanol also known as methyl alcohol is the simplest alcohol very similar to ethanol but slightly sweeter than it. Methanol is used for producing biodiesel via transesterification reaction. Methanol is mainly used as feedstock for producing other chemicals. In general methanol is converted into formaldehyde and from there converted into products as diverse as plastics, plywood, paints and explosives. Methanol is used in internal combustion engine as fuel on a limited basis. One of the drawbacks of methanol as a fuel is its corrosivity to some metals including aluminium. Natural gas is the most economical and widely used feedstock for methanol production at a certain temperature and pressure, the methane component in natural gas reacts with steam on a nickel catalyst to produce syngas.
The carbon monoxide and hydrogen then react in the presence of a copper, zinc oxide and alumina catalyst to produce methanol.
The US Department of Energy has patented a technology for production of methanol from CO2. The method involves synthesizing methanol from CO2 in air using electric power. Firstly, a solution of potassium hydroxide (KOH) is formed on reacting potassium with water. This is an exothermic reaction that doesn’t need any help in getting started and produces hydrogen as by-product. KOH solutions are ideal for use in CO2 scrubbers. The CO2 that passes through reacts with KOH to form potassium carbonate or bicarbonate. The solution on electrolysis gets converted into reactive components of hydrogen, carbon and oxygen which can react further to form methanol.
Mitsui chemical of Japan has decided to construct a pilot plant for continued development of producing methanol from industrial CO2 effluent. The construction will be at the company’s Osaka facilities where some 150 to 160 tons of CO2 can be obtained. The new plant is based on the cooperative work of Mitsui and the Research Institute of Innovative Technology for the Earth in Kyoto, Japan. Mitsui has a nearly ten-year investment in the effort during the 1990s from which it is bringing a single unit photoelectrocatalyst hydrogen production technology. This process uses a highly efficient thin film, anatase titania photo catalyst that has a photon to current quantum efficiency of 60%.
The company has started commercial production of methanol from its pilot plant in May 2010. The pilot plant will produce 100 million tonnes of methanol per year as a base material for plastics from the CO2 released during ethylene production at their Osaka plant. According to an estimate, it can convert about 50% of the CO2 emitted from their plant into methanol. The process relies on hydrogen obtained from water photolysis and ultra high activity electro catalysts consisting of zinc and copper.