The proton N M R second moment and spin-lattice relaxation time for tetrapropylammonium bromide and iodide have been measured over a wide temperature range. A solid-solid phase transition related to the onset of cation tumbling was found for both salts and confirmed by DTA. In the low temperature phases methyl group reorientation was evidenced. For iodide a dynamic nonequivalence of the methyl ...

The Kirkendall effect was utilized to synthesize mesoporous silicalite-1 zeolite nanocrystals without the involvement of additional templates. The mesopore size as well as the particle size can be easily controlled by nanoscale Kirkendall growth via significantly reducing the amount of water or tetrapropylammonium hydroxide, which were used in large quantities in conventional methods. The Kirke...

The fast growing family of organic-inorganic hybrid compounds has recently been attracting increased attention owing to the remarkable functional properties (magnetic, multiferroic, optoelectronic, photovoltaic) displayed by some of its members. Here we show that these compounds can also have great potential in the until now unexplored field of solid-state cooling by presenting giant barocalori...

‘H magic angle spinning nuclear magnetic resonance (MAS NMR) measurements on ZSM-5 synthesized with tetrapropylammonium ions as structure-directing template, calcined and hydrogen exchanged, indicate high concentrations of silanol groups (up to 4.6~ 10zo SiOH g-‘)_ ‘H NMR, “Na and % MAS NMR studies of zeolites ZSM-5 with different Si/Al ratios support a model which attributes the majority of th...

a new polymorph crystalline silica composition having uniform pore dimensions were synthesized by calcining a crystalline hydrated alkyl-ammonium silicate. the pore dimensions approximately were 6 angstrom for silicalite-1 and 11 angstrom for silicalite-2 units. the silicalite-1 was prepared hydrothermally at a ph of about 10 from a reaction mixture consist of water, amorphous silica and a quat...