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A diesel fuel desulfurized to 76 and 13 ppm sulfur in the aromatic fraction was analyzed with the objective of performing a speciation of the polycyclic aromatic sulfur heterocycles present. This provides information of importance to catalyst and process development. The analysis was based on selectively separating the sulfur from the non-sulfur aromatic compounds on a Pd II -containing liquid chromatographic phase, followed by identification and quantification using gas chromatography with mass-selective and sulfur-selective atomic emission detection. Several newly synthesized alkyldibenzothiophenes (mainly C 3 -and C 4 DBTs) could be quantified, and isomers with up to six alkyl carbon atoms could be detected in the diesel fuel. Besides confirmation that substituents in the 4 position of a dibenzothiophene lead to low rates of hydrodesulfurization (HDS), it is reported for the first time that a methyl group in the 1 position can also lead to a lower reactivity under HDS conditions, allowing such compounds to accumulate in the deeply desulfurized products. It is suggested that the nonplanarity of the aromatic system in such compounds is associated with this phenomenon.

The lowering of the legal concentration of sulfur in fuels (in the European Union from 150 ppm at present to 50 ppm in 2004) not only affects the concentration but also the pattern of the polycyclic aromatic sulfur heterocycles (PASH) in the fuels. This pattern was studied for 12 diesel samples, most of which have been desulfurized. A separation of the PASHs and the polycyclic aromatic hydrocarbons becomes necessary at such sulfur levels. An efficient liquid chromatographic method for this is presented and involves a Pd(II)-containing complex based on 2-amino-1-cyclopentene-1-dithiocarboxylate covalently bonded to silica. The resultant PASH fraction can be analyzed by gas chromatography/flameionization detection.

The ongoing global trend toward carbon dioxide emission reduction forced the automotive industry to design lighter and resource-efficient vehicle bodies, leading to the huge success of the press hardening process. [1][2][3][4][5] One reason for this success lies in the availability of thin-walled ultrahigh strength steel 22MnB5, which combines good formability and highest strength properties of 1500 MPa at a fully martensitic structure after press hardening at reasonable costs. [6,7] Since the first application in the automotive industry in 1986 as a side-impact beam, [8] the application field of 22MnB5 components increases continuously from B-pillar to roof rail reinforcement and other parts to enhance passenger safety. [9,10] The thermomechanical approach of press hardening allows the production of complex-shaped components with high dimensional accuracy, [11] excellent mechanical properties, and, at the same time, offers the opportunity for realizing tailored properties. [12,13] Although a time-temperature course of uniform austenitization and quenching in a cooled forming tool, Figure 1a, results in a homogenous fully martensitic structure with highest strength, a locally varying time-temperature course during the forming process, Figure 1b, enables the creation of a tailored distribution of microstructures, where mechanical properties are locally adjusted to perfectly meet the load profile, e.g., in case of crash-relevant components. [5,6] According to Ademaj et al., after uniform austenitization at 930 C but differential cooling of 22MnB5, zones following "route H" develop highest tensile strengths (1500 MPa) whereas zones following "route S" show lower tensile strength properties (614 MPa). [14] Both process strategies of Figure 1 are chosen for the current study with respect to the aforementioned investigations.This approach has been identified as a viable option to obtain lighter body structures through the ability to design load adapted structures and to combine contradictory requirements within one component. [14,15] A prominent example in car body structures is the B-pillar, in which the bottom section exhibits higher