Hydrogenator
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A hydrogenator is a device used in chemistry (and chemical industry) to hydrogenate various chemical compounds, generally organic compounds, such as unsaturated oils.
Contents
General
Hydrogenators are devices constructed of hydrogen embrittlement-resistant metals, usually special types of stainless steel. They consist of a source of hydrogen, generally compressed hydrogen tanks. Various pressure gauges, either mechanical of electronic are used to display the pressure inside the reactor and gas cylinder. The reactor consists of a cylindrical or spherical (rarer) body, where metal catalysts are used to initiate the hydrogenation reaction. A compressor is used to achieve the desired pressure inside the reactor, while the temperature is regulated through a thermocouple.
Low pressure hydrogenators are more common and simpler to use, although they can't hydrogenate all chemical compounds.
Catalysts
As elemental hydrogen is nonreactive to most organic compounds, a catalyst is required to initiate the hydrogenation process. Common catalyst used in hydrogenators are transition metals (iron in the Haber-Bosch process), metal on carbon (Pd/C), noble metals (platinum, palladium, rhodium, ruthenium), nickel alloys (Raney nickel or Urushibara nickel), various coordination complexes of platinum metals (Wilkinson's catalyst, dichlorotris(triphenylphosphine)ruthenium(II)), alkoxides (t-BuOK, aluminium isopropoxide) etc.
Availability
Industrial entities sell various hydrogenators, though they're expensive.
DIY hydrogenator
A good hydrogenator is difficult to make as most OTC materials don't have both embrittlement resistance and good compression strength, necessary for achieving high pressures. For lower pressures, steel tanks can be used, although if the alloy is susceptible to embrittlement, it cannot be run for long time.
Low (or room) pressure hydrogenators can be made by using a source of hydrogen such as compressed hydrogen, various hydrides or Raney nickel and a glass container, such as Erlenmeyer or filter flask, and certain catalysts.
Projects
- Hydrogenate unsaturated oils
- Make cyclohexane from benzene
- Make ammonia (Haber-Bosch process)
Safety
As working with hydrogenators generally involves pressurized hydrogen, there is a risk of explosion in the event of an accident. Since hydrogen is very flammable, proper ventilation must be in place, for all types of hydrogenation.
Legality
Although the ownership of a hydrogenator is not illegal in most countries, their purchase may be monitored, due to their use in drug making. In US, hydrogenators are included in the DEA Special Surveillance List, in the equipment section, and their sale is monitored.
