Structural parameters of zeolitic catalysts (faujasite NaX and NaY) with chemisorbed methyl groups by neutron diffraction and13C MAS NMR

'H MAS NMR Studies of Alumina-Supported Metal Oxide Catalysts

The interactions of two-dimensional vanadium oxide and molybdenum oxide overlayers with the surface hydroxyls of an alumina support were examined with 'H MAS NMR spectroscopy. The measurements demonstrated that these surface metal oxide overlayers are homogeneously distributed over the alumina surface and essentially titrate all the accessible surface hydroxyls at monolayer coverage. The invest...

31P CP/MAS NMR of polycrystalline and immobilized phosphines and catalysts with fast sample spinning

Cross-polarization (CP) at fast magic angle spinning (MAS) frequencies leads to a splitting of the Hartmann–Hahn (HH) matching profile into a centerband and additional bands of higher orders. The matching profiles differ with the substance categories. Therefore, signal intensity is usually lost, when e.g. the routine standard NH4H2PO4 is used for optimizing the 1H–31P HH match prior to measurin...

Reaction of functionalized anilines with dimethyl carbonate over NaY faujasite. 3. chemoselectivity toward mono-N-methylation.

In the presence of NaY faujasite, dimethyl carbonate (MeOCO(2)Me, DMC) is a highly chemoselective methylating agent of functionalized anilines such as aminophenols (1), aminobenzyl alcohols (2), aminobenzoic acids (3), and aminobenzamides (4). The reaction proceeds with the exclusive formation of N-methylanilines without any concurrent O-methylation or N-/O-methoxy carbonylation side processes....

Monitoring by in situ neutron diffraction of simultaneous dehydration and Ni2+ mobility in partially exchanged NaY zeolites

Structural investigations of poly(methyl methacrylate) by two-dimensional NMR

In the present paper a comprehensive microstructure analysis of PMMA based on the combination of one-dimensional and twodimensional (TOCSY, HSQC, and HMBC) NMR experiments is reported. To resolve complex resonance assignments, empirical chemical shift modeling supported by the 2D NMR spectroscopy has been done. Rigorous assignments of resonance signals have been done by investigating the one bo...