Indian chemists have developed porous solid acids that can be a safe replacement for conventional liquid acids used in catalysis of many industrially important reactions.
In recent years, the chemical industry has been looking at solid acids with increasing interest. It is believed that they will become a relatively “clean” replacement for conventional liquid acids as catalysts, which are used in many chemical processes – from the cracking of oil and the destruction of plastics to the synthesis of fuels from atmospheric carbon dioxide. These substances include, say, crystalline aluminum (III) oxides or zeolites.
However, if zeolites exhibit the desired acidic properties, then their structure is far from ideal. An effective heterogeneous catalyst requires maximum surface area and must be porous, like aluminas, which, in turn, are not very acidic. The best option should combine both pronounced acidity and porous structure – such materials are sometimes called “amorphous zeolites”.
A similar substance was obtained by the team of Vivek Polshettiwar from the Tata Institute for Basic Research in Mumbai. They report this in an article published in the journal Nature Communications. Laboratory experiments have shown that such an “amorphous zeolite” is indeed capable of catalyzing the conversion of carbon dioxide into fuel (dimethyl ether), and plastic waste into useful hydrocarbons.
The authors used a method with the deposition of microemulsion droplets on the surface of a soft substrate and polymerization. This made it possible to obtain an amorphous zeolite with a porous structure, demonstrating pronounced acidic properties. The catalytic ability of this material was found to be higher than that of the best existing samples of conventional zeolites and aluminosilicates. Scientists are confident that soon the new technology will provide materials for practical use on a large scale.