377
edits
Lars Krause (talk | contribs) |
|||
Line 5: | Line 5: | ||
=== Origin and composition === | === Origin and composition === | ||
Due to the wide range of available catalysts and the large spectrum of reactions they can catalyse, the feedstock range for heterogeneous catalysis is significant. This ranges from biomass feedstocks such as lignocellulose | Due to the wide range of available catalysts and the large spectrum of reactions they can catalyse, the feedstock range for heterogeneous catalysis is significant. This ranges from biomass feedstocks such as lignocellulose, lignin, cellulose, sugars, and fatty acids, to products derived from biomass, such as glycerol and furfural.<ref name=":1" /> | ||
=== Pre-treatment === | === Pre-treatment === | ||
The pre-treatment of the feedstock for a heterogeneous catalysis is depending on the specific process and feedstock used. In principal the feedstock normally is a liquid or gas so for solid feedstocks a conversion process like a pyrolysis or gasification or a solution is needed. | |||
==Process and technologies== | ==Process and technologies== | ||
A wide range of processes and technologies can make use of heterogeneous catalysts. Examples are [[pyrolysis]], hydro-processing, [[oxidation]], amination, dehydration, [[hydrolysis]], (trans)esterification, and isomerisation.<ref name=":1" /> The most common heterogeneous catalysts are heterogeneous solid base catalysts and heterogeneous solid acid catalysts. Base catalysts have a high concentration of basic sites that ensures the catalytic activity, often from Ba, Ca, Mg, and Sr and can be mixed or doped. Soap formation is a recurring drawback of these systems. Acid catalysts get their activity either from Brønsted or Lewis acidity and are commonly zirconia, silica, zeolites or zeotype materials. Major advantages of heterogeneous catalysis is the ease of separation, recyclability and high selectivity.<ref name=":0" /> Current development for future heterogeneous catalytic systems are in metal-organic frameworks (MOFs), magnetic catalysts, and solid phase ionic liquids.<ref name=":1" /> | A wide range of processes and technologies can make use of heterogeneous catalysts. Examples are [[pyrolysis]], hydro-processing, [[oxidation]], amination, dehydration, [[hydrolysis]], (trans)esterification, and isomerisation.<ref name=":1" /> The most common heterogeneous catalysts are heterogeneous solid base catalysts and heterogeneous solid acid catalysts. Base catalysts have a high concentration of basic sites that ensures the catalytic activity, often from Ba, Ca, Mg, and Sr and can be mixed or doped. Soap formation is a recurring drawback of these systems. Acid catalysts get their activity either from Brønsted or Lewis acidity and are commonly zirconia, silica, zeolites or zeotype materials. Major advantages of heterogeneous catalysis is the ease of separation, recyclability and high selectivity.<ref name=":0" /> Current development for future heterogeneous catalytic systems are in metal-organic frameworks (MOFs), magnetic catalysts, and solid phase ionic liquids.<ref name=":1" /> | ||
==Product== | ==Product== | ||
Heterogeneous catalysis is widely used throughout chemistry and a plethora of products can be made. Heterogeneous catalysis is often used in the production of biodiesel<ref name=":0" />, but can also be employed in the [[pyrolysis]] process or in the production of many other value added chemicals.<ref name=":1" /> | Heterogeneous catalysis is widely used throughout chemistry and a plethora of products can be made. Heterogeneous catalysis is often used in the production of biodiesel<ref name=":0" />, but can also be employed in the [[pyrolysis]] process or in the production of many other value added chemicals.<ref name=":1" /> | ||
=== Post-treatment === | === Post-treatment === | ||
The post-treatment of the products of a heterogeneous catalysis is depending on the specific process and final products aimed for. | |||
==Technology providers== | ==Technology providers== |