Fast (>I2 kHz) magic-angle-spinning NMR with IH' 7AI cross-polarization quantitatively monitors several aluminous species in dealuminated zeolite Y; the non-framework matter contains 4-, 5-and 6-coordinated A1 and the *7AI signal at 30 ppm is an independent resonance probably due to 5-coordinated non-framework Al and not part of a second-order quadrupole lineshape as previously reported. Since ...

Synthesis and overexpression of a gene encoding Escherichia coli UDP-galactose 4-epimerase and engineered to facilitate cassette mutagenesis are described. General acid-base catalysis at the active site of this epimerase has been studied by kinetic and spectroscopic analysis of the wild-type enzyme and its specifically mutated forms Y149F, S124A, S124V, and S124T. The X-ray crystal structure of...

The manuscript is an update to the earlier Science of Synthesis contribution describing methods for the synthesis and new applications of thiocarbonyl S-oxides (sulfines) and thiocarbonyl S-imides. In general, thiocarbonyl S-oxides are more stable and in many instances they can be isolated in substance. The in situ generated thiocarbonyl S-imides are efficient ‘sulfur transferring agents’ via t...

T H E NATURE of pyridine adsorption by acidand base-saturated montmorillonite from Otay, California (A.P.I, no. H-24) was studied by infrared adsorption. The spectrum for chemisorbed pyridine was found to be distinctively different from physically adsorbed pyridine; the latter gave a spectrum very similar to liquid pyridine. Upon exposure of the clay films to pyridine at low vapor pressures, on...

a convenient and efficient direct protocol for the preparation of antibacterial azo dyes by the reaction of 2-naphthol with aromatic amines in the presence of catalytic amount of n-methyl-2-pyrrolidonium hydrogen sulfate ([h-nmp]hso4) was carried out under solvent free conditions. this method has some advantages such as: easy work-up and easy separation of catalyst from the reaction mixture. th...

In the present of methylimidazolium hydrogen sulfate, the synthesis of arylidene heterobicyclic pyrimidinones is studied by condensation of aromatic aldehyde, cyclopentanone, and urea or thiourea. Using solvent-free conditions, non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.

The chemistry of hypervalent iodine(III) compounds has gained great interest over the past 30 years. Hypervalent iodine(III) compounds show valuable ionic reactivity due to their high electrophilicity but also express radical reactivity as single electron oxidants for carbon and heteroatom radical generation. Looking at ionic chemistry, these iodine(III) reagents can act as electrophiles to eff...

In the present of methylimidazolium hydrogen sulfate, the synthesis of arylidene heterobicyclic pyrimidinones is studied by condensation of aromatic aldehyde, cyclopentanone, and urea or thiourea. Using solvent-free conditions, non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.

The kinetics and reaction network of hydrodemetallation (HDM) reactions and the pattern of metal deposition have been investigated using a model residuum oil, consisting of nickel porphyrins (Nietioporphyrin (Ni-EP), Ni-tetraphenylporphyrin (Ni-TPP), and Nitetra(3-methylphenyl)porphyrin (Ni-T3MPP)) dissolved in a clean (N and S free) mineral oil. Reactions were carried out over a commercial CoO...

-The acidic properties of acid-modified montmorillonite and vermiculite were determined by pyridine and ammonia adsorption to correlate with the alkylating and dehydrating activity of the activated samples. Treatment of the minerals with different concentrations of hydrochloric acid results in the variation of overall acidity and density of acidic sites. Infrared (IR) spectral and differential ...