38734-69-9Relevant articles and documents
Pd Nanoparticles Encapsulated in FER Zeolite through a Layer Reassembling Strategy as Shape-selective Hydrogenation Catalyst
Zhao, Zhenchao,Li, Yanlu,Feyen, Mathias,McGuire, Robert,Müller, Ulrich,Zhang, Weiping
, p. 2254 - 2259 (2018/03/21)
Noble metal nanoparticles (NPs) encapsulated in zeolites bearing distinct shape-selective properties at molecular level expand their new applications in catalysis. Here we report a synthesis strategy for the encapsulation of Pd NPs inside FER zeolite via a layer reassembling process. Pd precursors were introduced by swelling FER layers in RUB-36 through the surfactant cetyltrimethylammonium cations (CTA+) and then an ion-exchange process at ambient temperature. Pd@FER was formed with a uniform diameter distribution of Pd NPs at about 1.4 nm during the topotactic transformation from layered zeolite precursors to 3-dimensional zeolites followed by calcination. The as-prepared Pd@FER catalyst exhibits distinct shape-selective properties in hydrogenation reactions. It has relatively lower activity for 1-hexene and almost no activity for 1-phenyl-1-cyclohexene compared with Pd/RUB-37 catalyst prepared via wet impregnation due to the restrictions of channels in the FER zeolite. On the contrary, Pd@FER shows very high hydrogenation activity for benzaldehyde and very low activity for diphenylmethanone hydrogenation, while Pd/RUB-37 exhibits high hydrogenation activity for both benzaldehyde and diphenylmethanone. This synthesis strategy may be extended to other noble metals or two-dimensional layered zeolite systems for size-selective hydrogenation reactions.
With fluorescence of a process for the preparation of carboxylic acid ammonium salt (by machine translation)
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Paragraph 0041; 0042, (2016/10/20)
The present invention provides a fluorescent carboxylic acid ammonium salt preparation method, the steps are as follows: the carboxylic acid and organic amine dissolved in distilled water, under the protection of nitrogen disposal in the flask, ultrasonic oscillation to dissolve, in the 0 °C -30 °C, stirring reaction 12-36h, is the main component of the aqueous solution of the carboxylic acid ammonium salt mixture; with petroleum ether carboxylic acid ammonium salt mixture of the aqueous solution after washing three times, the aqueous phase under reduced pressure to obtain the spin vaporization with fluorescent carboxylic acid ammonium salt; carboxylic acid ammonium salt of the present invention, the preparation method is simple, high yield, has excellent fluorescence properties, the change of the at the same time, as the excitation wavelength, emission wavelength thereof is also changed, with excitation wavelength-dependent. The trivalent iron ions and has good identification, their iron ion concentration of reduced in the decrease of the strength and exhibits a linear relationship. (by machine translation)
Characterization of unstable products of flavin- and pterin-dependent enzymes by continuous-flow mass spectrometry
Roberts, Kenneth M.,Tormos, José R.,Fitzpatrick, Paul F.
, p. 2672 - 2679 (2014/05/20)
Continuous-flow mass spectrometry (CFMS) was used to monitor the products formed during the initial 0.25-20 s of the reactions catalyzed by the flavoprotein N-acetylpolyamine oxidase (PAO) and the pterin-dependent enzymes phenylalanine hydroxylase (PheH) and tyrosine hydroxylase (TyrH). N,N′-Dibenzyl-1,4-diaminobutane (DBDB) is a substrate for PAO for which amine oxidation is rate-limiting. CFMS of the reaction showed formation of an initial imine due to oxidation of an exo-carbon-nitrogen bond. Nonenzymatic hydrolysis of the imine formed benzaldehyde and N-benzyl-1,4-diaminobutane; the subsequent oxidation by PAO of the latter to an additional imine could also be followed. Measurement of the deuterium kinetic isotope effect on DBDB oxidation by CFMS yielded a value of 7.6 ± 0.3, in good agreement with a value of 6.7 ± 0.6 from steady-state kinetic analyses. In the PheH reaction, the transient formation of the 4a-hydroxypterin product was readily detected; tandem mass spectrometry confirmed attachment of the oxygen to C(4a). With wild-type TyrH, the 4a-hydroxypterin was also the product. In contrast, no product other than a dihydropterin could be detected in the reaction of the mutant protein E332A TyrH.
Preparation of 2-imidazolines
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, (2008/06/13)
A novel process for the preparation of 2-imidazolines by reacting 1,2-diamines with nitriles or carbonyl compounds in the gas phase at from 200° to 450° C. in the presence of an oxide or phosphate of a metal of group 3 or 4 of the periodic table and/or in the presence of silicon dioxide. The 2-imidazolines obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents and drugs.
