Topic
Selectivity
About: Selectivity is a research topic. Over the lifetime, 9445 publications have been published within this topic receiving 227360 citations.
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TL;DR: In this article, the authors tried to improve both the selectivity and the permeation rates for the separation of 1-methylnaphthalene from dodecane using aqueous surfactant membranes.
5 citations
Patent•
31 Oct 2012
TL;DR: In this article, super hydrophobic nano-sized complex oxide material is used as catalyst to apply to a solvent-free hydrocarbon selective oxidation reaction and high conversion rate and selectivity of organic oxygen-contained compounds (alcohol, ketone, aldehyde, and acid) are obtained simultaneously.
Abstract: Disclosed is a hydrocarbon catalyzed selective oxidation method. Super hydrophobic nano-sized complex oxide material is used as catalyst to apply to a solvent-free hydrocarbon selective oxidation reaction. Due to the super hydrophobic property of the material, absorption of substrate and desorption of product are facilitated, and high conversion rate and selectivity of organic oxygen-contained compounds (alcohol, ketone, aldehyde, and (or) acid) are obtained simultaneously.
5 citations
TL;DR: In this paper, the interactions of piperidine, 3,5-dimethylpiperidine and pyridine with a reduced Ni/SiO 2 sample have been studied as a function of the temperature, using magnetic measurements, infrared spectroscopy and catalytic activity changes in the hydrogenation of 1,3 butadiene.
Abstract: The interactions of piperidine, 3,5-dimethylpiperidine and pyridine with a reduced Ni/SiO 2 sample have been studied as a function of the temperature, using magnetic measurements, infrared spectroscopy and catalytic activity changes in the hydrogenation of 1,3 butadiene. The three cyclic nitrogen-containing compounds (CNCC) are adsorbed at room temperature without cracking of the molecule: the bond number (number of nickel atoms demagnetized by the adsorption of one adsorbate molecule) is equal to 2,4 and 6 for piperidine, 3,5-dimethylpiperidine and pyridine respectively. For the first two CNCC, the increase of the adsorption temperature considerably increases the bond number; at 373 K, it reaches values of 12 for piperidine and 24 for 3,5-dimethylpiperidine. These values show that a complete cracking of the two molecules does not occur. In the case of pyridine adsorption, a constant bond number close to 7 was observed in the 298–373 K temperature range. Regeneration of the poisoned catalysts was performed by vacuum treatments at increasing temperature. During this process the insertion of nitrogen and carbon atoms in the metal lattice has been evidenced. Regeneration under flowing hydrogen was more efficient than treatment under vacuum. Concerning the hydrogenation of 1,3-butadiene, the addition of CNCC leads to a decrease of the catalytic activity associated with an increase of the selectivity for partial hydrogenation. By contrast with the introduction of ammonia, these effects are permanent, i.e., changes in catalytic activity and selectivity are maintained even after the removal of the CNCC from the feed. The increase in the selectivity in partial hydrogenation of 1,3-butadiene was explained by an electron enrichment of the metallic sites in the presence of cyclic nitrogen-containing compounds.
5 citations
Patent•
09 Jun 2010
TL;DR: In this paper, a process for preparing 1,1,1-trifluoroethane (HFC-143a) features the gas phase reaction between HF and HCC-140a under the existence of fluorinating Cr-base catalyst at 150-280deg.
Abstract: A process for preparing 1,1,1-trifluoroethane (HFC-143a) features the gas-phase reaction between HF and 1,1,1-trichloroethane (HCC-140a) under the existence of fluorinating Cr-base catalyst at 150-280deg.C. It has high output rate and selectivity.
5 citations
TL;DR: In this paper, the selectivity of 4-chloro-2-nitrophenol on 5% Pd/C catalyst was achieved in 5 h. At a conversion ratio of 87%, 96% selectivity was achieved.
5 citations