home

[[image:utilizatioofcarbondioxide/co2_emissions_main.jpg width="389" height="164" align="right"]]
Carbon dioxide(CO₂) is an ideal synthetic feedstock since it is abundant, inexpensive, nontoxic and nonflammable. Its occurrence in the atmosphere is roughly 2.3 x10 12 t while about 1.4 x 10 14 t are stored in our oceans. Thus, CO₂ is a carbon source which is not only available in large amounts, but also has a regenerative character due to its integration in its natural cycle. The utilization of CO₂ as a building block for chemical reactions can be described as Green Chemistry. Only a few processes based on CO₂ as a raw material were realized in a technical scale so far.

Carbon dioxide (CO2) is available in almost infinite amounts in our atmosphere and oceans, but its utilisation as feedstock for the chemical industry is often prevented by its thermodynamic stability. Although it is estimated that nature uses CO2 to make over 200 billion tons of glucose by photosynthesis each year, synthetic chemists have had little success in developing efficient catalytic processes that exploit this attractive raw material. Only a few processes based on CO2 as a raw material were realised in a technical scale so far, such as the production of urea, methanol or salicylic acid.

In the present research, mainly catalytic reactions of a lactone platform chemical are described whose production is based on CO₂ as a feedstock. Based on its different functional groups, numerous reactions can be carried out starting from this molecule leading to versatile and interesting products: acids, alcohols or diols as well as aldehydes, amino acids or amines are formed in high yields. Furthermore, esters, silanes or even polymers are obtained using the δ-lactone as a building block. Thus, by applying efficient catalytic systems which lead to high selectivities, a new approach for the utilization of CO₂ as a reasonable feedstock for chemical reactions is described. Because of its thermodynamic stability and high oxidation state, its utilization has been realized in only few cases: the synthesis of urea, methanol, cyclic carbonates and salicylic acid are the most important processes which could be realized economically in this context. Other processes suffer from the high costs of CO₂ activation. Finally, a catalytic process was found to be the best way to overcome these difficulties.

The resulting δ-lactone is highly functional which leads to various reactivities. It has a carboxyl group, an internal carbon-carbon double bond and a further terminal carbon- carbon double bond. Up to now, the molecule itself did not find an application. Through further conversion with different bulk chemicals, several secondary products of potential industrial relevance have been synthesized mainly catalytically. These conversion reactions of the δ-lactone are discussed in the following sections demonstrating that CO₂ can be efficiently integrated as a building block for many organic substances.

__General Outline__
The following concepts will be covered: Next Page CO₂δ
 * 1) Synthesizing δ-lactone
 * 2) Conversion of δ-lactone
 * 3) Application of Green Chemistry