C factors pinpoint resource utilization in chemical industrial processes.

This Full Paper illustrates the use of the C factor (CO(2)/product mass ratio) as a parameter to evaluate the CO(2)-burden of a product. The C factor contains information of the total amount of CO(2) emitted in order to produce a product, and thus enables a direct comparison of different processes from a CO(2) aspect. We illustrate how this simple concept can be used to evaluate different resource types and processes. The C factors for different chemicals such as methanol, synfuels, and acetic acid are calculated for oil, coal, natural gas, and biomass. Based on these calculations, the combination of biomass and natural gas is an attractive alternative to coal, leading to products that have significantly lower C factors.

The renewable chemicals industry.

The possibilities for establishing a renewable chemicals industry featuring renewable resources as the dominant feedstock rather than fossil resources are discussed in this Concept. Such use of biomass can potentially be interesting from both an economical and ecological perspective. Simple and educational tools are introduced to allow initial estimates of which chemical processes could be viable. Specifically, fossil and renewables value chains are used to indicate where renewable feedstocks can be optimally valorized. Additionally, C factors are introduced that specify the amount of CO2 produced per kilogram of desired product to illustrate in which processes the use of renewable resources lead to the most substantial reduction of CO2 emissions. The steps towards a renewable chemicals industry will most likely involve intimate integration of biocatalytic and conventional catalytic processes to arrive at cost-competitive and environmentally friendly processes.

A molecular view of heterogeneous catalysis.

The establishment of a molecular view of heterogeneous catalysis has been hampered for a number of reasons. There are, however, recent developments, which show that we are now on the way towards reaching a molecular-scale picture of the way solids work as catalysts. By a combination of new theoretical methods, detailed experiments on model systems, and synthesis and in situ characterization of nano-structured catalysts, we are witnessing the first examples of complete atomic-scale insight into the structure and mechanism of surface-catalyzed reactions. This insight has already proven its value by enabling a rational design of new catalysts. We illustrate this important development in heterogeneous catalysis by highlighting recent examples of catalyst systems for which it has been possible to achieve such a detailed understanding. In particular, we emphasize examples where this progress has made it possible to propose entirely new catalysts, which have then been proven experimentally to exhibit improved performance in terms of catalytic activity or selectivity.

Generation of nanopores during desorption of NH3 from Mg(NH3)6Cl2.

It is shown that nanopores are formed during desorption of NH3 from Mg(NH3)6Cl2, which has been proposed as a hydrogen storage material. The system of nanopores facilitates the transport of desorbed ammonia away from the interior of large volumes of compacted storage material. DFT calculations show that there exists a continuous path from the initial Mg(NH3)6Cl2 material to MgCl2 that does not involve large-scale material transport. Accordingly, ammonia desorption from this system is facile.

Catalytic benzene alkylation over mesoporous zeolite single crystals: improving activity and selectivity with a new family of porous materials.

Mesoporous zeolite single-crystal catalysts are shown to be both more active and more selective than conventional zeolite catalysts in the alkylation of benzene with ethene. The superior catalytic properties are ascribed to improved mass transport in the mesoporous zeolite crystals. Thus, mesoporous zeolite single-crystal catalysts combine the high acidity, shape-selectivity, and hydrothermal stability of zeolites with the efficient mass transport that is typically achieved in mesoporous materials.