Bertram Böhringer

New element organic frameworks viaSuzuki coupling with high adsorption capacity for hydrophobic molecules

We present new highly microporous element organic frameworks synthesized by the Pd catalyzed Suzuki coupling reaction. They show specific surface areas of up to 1380 m2 g−1 with a strong hydrophobic character. Thus, they are interesting for the adsorption of non-polar substances. By variation of the organic linkers, the modular concept of the materials in analogy to the metal–organic frameworks is demonstrated. The polymeric materials have thermal stability up to 573 K and show no decomposition in aqueous environment, allowing excellent handling and processing. They are accessible by a basic synthetic approach, and by their chemical and thermal stabilities they may provide adequate properties for applications in many fields, especially in adsorptive separation processes and storage of non-polar gases.

A new route to porous monolithic organic frameworks via cyclotrimerization

Cyclotrimerization of bifunctional acetyl compounds is used to obtain highly porous organic frameworks. Syntheses in solution induced by silicon tetrachloride result in highly disperse powders while syntheses in molten 4-toluene sulfonic acid result in polymeric monoliths with a hierarchical pore structure containing micro- and macropores allowing for direct impregnation of textiles with a porous polymer. The materials show specific BET surface areas up to 895 m2 g−1 and large pore volume (1.99 cm3 g−1) combined with a highly hydrophobic character. The amorphous materials are thermally stable below 300 °C in air and show no decomposition effects in aqueous environment. These outstanding properties in combination with the opportunity to generate shapes of any kind desired for an application render the materials as highly promising for application in air filtration systems and individual protection, as well as gas storage and separation.

Decomposition of 2-chloroethylethylsulfide on copper oxides to detoxify polymer-based spherical activated carbons from chemical warfare agents

For the decomposition of chemical warfare agents, a hybrid material concept was applied. This consists of a copper oxide-containing phase as a component with reactive functionality supported on polymer-based spherical activated carbon (PBSAC) as a component with adsorptive functionality. A corresponding hybrid material was prepared by impregnation of PBSAC with copper(II)nitrate and subsequent calcination at 673K. The copper phase exists predominantly as copper(I)oxide which is homogeneously distributed over the PBSAC particles. The hybrid material containing 16 wt.% copper on PBSAC is capable of self-detoxifying the mustard gas surrogate 2-chloroethylethylsulfide (CEES) at room temperature. The decomposition is related to the breakthrough behavior of the reactant CEES, which displaces the reaction product ethylvinylsulfide (EVS). This leads to a combined breakthrough of CEES and EVS. The decomposition of CEES is shown to occur catalytically over the copper-containing PBSAC material. Thus, the hybrid material can even be considered to be self-cleaning.

Supported ionic liquid phase (SILP) materials for removal of hazardous gas compounds – efficient and irreversible NH3 adsorption

Novel supported ionic liquid phase (SILP) gas purification materials have been developed to remove ammonia irreversibly from an ambient gas flow of nitrogen (1000 ppm NH3 in N2, wet and dry). In the applied SILP materials, thin films of imidazolium based ionic liquids and ionic solutions of metal complexes, namely [C8C1Im][NTf2], [C8C1Im][NTf2]/Cu(NTf2)2, [C8C1Im][NTf2]/Co(NTf2)2 and [CnC1Im]Cl/CuCl2 (n = 2, 4, 8), were dispersed onto the large surface area of polymer-based spherical activated carbon supports. For the [CnC1Im]Cl/CuCl2 (n = 2, 4, 8) based SILP materials the use of a humid gas flow significantly enhances NH3 absorption as demonstrated by a clear increase of breakthrough times. The irreversibility of the ammonia sorption and the broadband capability (e.g. Cl2, H2S and cyclohexane) of the prepared SILP absorber materials are reported and compared to typical standards for gas purification adsorber materials (ABEK regulations).