Biphenyl-4,4′-dicarb­oxy­lic acid N,N-dimethyl­formamide monosolvate

Biphenyl-4,4′-dicarb­oxy­lic acid was recrystallized from N,N-dimethyl­formamide (DMF) yielding the title compound, C14H10O4·2C3H7NO. The acid mol­ecules are located on crystallographic centres of inversion and are hydrogen bonded to DMF mol­ecules. These hydrogen-bonded units form infinite chains although there is no inter­action between the methyl groups of neighboring DMF mol­ecules

Poly[tris­(μ-2-amino­benzene-1,4-dicarboxyl­ato)tetra­kis­(N,N-dimethyl­formamide)­diyttrium(III)]

The asymmetric unit of the title coordination polymer, [Y2(C8H5NO4)3(C3H7NO)4]n, contains one Y3+ ion, three half-mol­ecules of the 2-amino­benzene-1,4-dicarboxyl­ate (abz) dianion and two O-bonded N,N-dimethyl­formamide (DMF) mol­ecules. Each abz half-mol­ecule is completed by crystallographic inversion symmetry and its –NH2 group is disordered in each case [relative occupancies within the asymmetric unit = 0.462 (18):0.538 (18), 0.93 (2):0.07 (2) and 0.828 (16):0.172 (16)]. The combination of disorder and crystal symmetry means that each of the four C—H atoms of the benzene ring of each of the dianions bears a statistical fraction of an –NH2 group. The coordination geometry of the yttrium ion is a fairly regular YO8 square anti­prism arising from its coordination by two DMF mol­ecules, four monodentate abz dianions and one O,O-bidentate abz dianion. The polymeric building unit is a dimeric paddle-wheel with two metal ions linked by four bridging abz dianions. Further bridging linkages connect the dimers into a three-dimensional framework containing voids in which highly disordered DMF mol­ecules are presumed to reside

Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite

[EN] In this work, an extensive investigation of the preparation of a large body of desilicated ZSM-22 zeolites and their basic characterization is presented. We investigate the effects of the properties of the starting zeolite, and we employ mixtures of NaOH with CTAB or TBAOH as well as subsequent acid washings to create mesoporous zeolites. Scanning and transmission electron microscopy and nitrogen adsorption revealed that the cristal morphology of the starting zeolite appears to be the dominant parameter which influences the mesopore generation. Mesopores were effectively created within the rod-like commercial crystallites, whereas the thinner dimensions of the needle-shaped particles of the lab-made zeolite represent an obstacle for an intra-mesopore creation. The alkaline, surfactant-assisted or combined NaOH/TBAOH desilication methods resulted in mesopores with different shape and size from the commercial zeolite. The sequential acid washing generally resulted in increased micropore volume with respect to the desilicated samples. Elemental analysis showed that extra-framework Al species were generated upon the desilication treatments, which are eventually removed by the acid treatment. The acidity studied by FTIR demonstrated that this occurs without a marked modification of the Brønsted acidity, whereas the concentration of surface silanol hydroxyl groups is increased. The comparison between the total Al concentration and the amount of Al in acidic sites quantified by pyridine adsorption shows that the acidity was recovered after the acid washing and suggests that original non-acidic Al species in the starting materials may have a role in the formation of both Lewis and extra-framework species upon desilication.This publication is a part of the inGAP Centre of research-based Innovation, which receives financial support from the Norwegian Research Council under contract no. 174893. F.R and M.T.N thank to MINECO for financial support through projects MAT2015-71842-P and SEV-2012-0267. All the authors thank the Electron Microscopy Service of the Universitat Politecnica de Valencia.Del Campo Huertas, P.; Beato, P.; Rey Garcia, F.; Navarro, MT.; Olsbye, U.; Lillerud, K.; Svelle, S. (2018). Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite. Catalysis Today. 299:120-134. https://doi.org/10.1016/j.cattod.2017.04.042S12013429

Co-catalyst free ethene dimerization over Zr-based metal-organic framework (UiO-67) functionalized with Ni and bipyridine

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Modeling gas turbine materials’ hot corrosion degradation in combustion environments from H2‐rich syngas

Components of gas turbines (such as blades, vanes, combustor cans) exposed to combustion environments at high temperature are susceptible to hot corrosion attack. To successfully plan maintenance and to determine whether to operate in novel combustion modes (e.g., in integrated gasification combined cycles that incorporate pre-combustion carbon capture) predictions of hot corrosion component life must be made. In this paper, hot corrosion datasets relating to two alloys, MarM 509 (a cobalt-based superalloy), and Rene 80 (a nickel-based superalloy) form the basis of hot corrosion predictive lifetime models. The model framework is based on the two stages of incubation and propagation, with the transitions from incubation to propagation around the samples being based on Weibull statistics. The impact of a range of temperatures (including 700 and 900 °C), gas compositions (simulating the combustion of natural gas, H2-rich syngas, or partially cleaned syngas), and deposit chemistries/fluxes have been assessed. Predictions have been made including the expected damage spread for a range of different exposure conditions