Ultrasound assisted the chemoselective 1,1-diacetate protection and deprotection of aldehydes catalyzed by poly(4-vinylpyridinium)hydrogen sulfate salt as a eco-benign,efficient and reusable solid acid catalyst

Poly(4-vinylpyridinium) hydrogen sulfate solid acid was found to be efficient catalyst for preparation of 1,1-diacetate using ultrasound irradiation at ambient temperature and neat condition. Deprotection of the resulting 1,1-diacetates were achieved using the same catalyst in methanol solvent under ultrasound irradiation at room temperature. This new method consistently has the advantage of excellent yields and short reaction times. Utilization of solvent free, simple reaction conditions, isolation, and purification makes this manipulation very interesting from an economic and environmental perspective. Further, the catalyst can be reused and recovered for several times.     

On the Diffusion Limit of a Semiconductor Boltzmann–Poisson System Without Micro-Reversible Process

This paper deals with the diffusion approximation of a semiconductor Boltzmann–Poisson system. The statistics of collisions we are considering here, is the Fermi–Dirac operator with the Pauli exclusion term and without the detailed balance principle. Our study generalizes, the result of Goudon and Mellet [11 Goudon , T. , Mellet , A. ( 2003 ). On fluid limit for the semiconductors Boltzmann equation . J. Diff. Eqs. 189 : 17 – 45 . [Google Scholar]], to the multi-dimensional case.     

One‐pot,fast cyclopropanation reaction of indandione with various aldehydes in the presence of cyanogen bromide and trimethylamine

A new, fast, and easy one‐pot cyclopropanation reaction of aromatic and aliphatic aldehydes with 1H‐indene‐1,3(2H)‐dione and cyanogen bromide (BrCN) was developed for synthesizing 3′‐(aryl[alkyl])‐dispiro[indan‐2,1′‐cyclopropane‐2′,2′′‐indan]‐1,1′′,3,3′′‐tetrone in excellent yields in a short time (about 15 s) under basic media. All structures were characterized using IR, ¹H NMR, and ¹³C NMR spectroscopy techniques.     

Soret motion of a charged spherical colloid

The thermophoretic motion of a charged spherical colloidal particle and its accompanying cloud of counterions and coions in a temperature gradient is studied theoretically. Using the Debye-Hückel approximation, the Soret drift velocity of a weakly charged colloid is calculated analytically. For highly charged colloids, the nonlinear system of electrokinetic equations is solved numerically, and the effects of high surface potential, dielectrophoresis, and convection are examined. Our results are in good agreement with some of the recent experiments on highly charged colloids without using adjustable parameters.     

Solid-phase synthesis of arylidene and alkylidene malonates,as versatile intermediates,catalyzed using mesoporous poly-melamine–formaldehyde as a nitrogen-rich porous organic polymer (POP)

Research on Chemical Intermediates - An efficient solid/slurry-state synthesis of arylidene and alkylidene malonates as versatile intermediates is developed in the presence of mesoporous...     

DFT Study of Adsorption of (4E,6E)-4-(4-Hydroxyphenyldiazenyl)-N-((furan-2-yl)methylene)benzenamine on BN(6,6-8) Nanotube

Russian Journal of Physical Chemistry A - In the current study, the adsorption properties of the molecule (4E,6E)-4-(4-hydroxyphenyldiazenyl)-N-((furan-2-yl)methylene)benzenamine (AZO) on...     

Detection of illicit material using neutron activation: weakness and solutions

Poisoning the illicit materials by a neutron absorber leads to false detection when the detection is relied on combined thermal neutron activation and fast neutron activation to identify the elements of interest. The use of adjacent transmission thermal neutron detector for verifying the presence of neutron poisons and to trigger an alarm was investigated experimentally and using MCNP calculations. The illicit material of high hydrogen content will affect the detector response in the presence or absence of poisons.     

Investigating neutron back scattering technique for the detection of oil water separation levels in horizontal gravity oil separators

Journal of Radioanalytical and Nuclear Chemistry - Neutron backscattering technique is investigated as an alternative way for measuring the level of water in the horizontal oil gravity separators....