676-63-1Relevant academic research and scientific papers
Catalytic Properties of the Aluminium Form of Zeolite Y modified with Trifluoromethane
Kowalak, Stanislaw
, p. 2035 - 2046 (1988)
Trifluoromethane has been used in a gaseous fluorination of the aluminium form of zeolite Y in order to avoid removal of aluminium during fluorine modification, which was observed previously for the procedure with NH4F aqueous solution.The samples modified with CHF3 showed an increase in catalytic activity for reactions involving acid sites; however, the maximum activity was reached for much lower fluorine content and it was slightly lower than that for samples fluorinated with NH4F.
A pronounce approach on the catalytic performance of mesoporous natural silica toward esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols
Said, Abd El-Aziz A.,Abd El-Wahab, Mohamed M. M.,El-Gamal, Nadia O.,Goda, Mohamed N.
, p. 257 - 268 (2021/12/14)
Catalytic esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols in the liquid phase over unmodified natural silica catalyst has been studied. The virgin and calcined catalysts were characterized by thermal analyses (Thermogravimetry (TG) and diffrential thermal analysis (DTA)), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and N2 sorption analyses. The acidity of natural silica catalysts was investigated using isopropyl alcohol dehydration and chemisorption of pyridine and dimethyl pyridine. The results indicated that most of the acidic sites are of Br?nsted type and of intermediate strength. The effect of different parameters such as reaction time, molar ratio, catalyst dosage, and calcination temperature was studied. Natural silica catalyst exhibited excellent catalytic performance with a selectivity of 100% to acetate esters formation. The maximum yields of isoamyl, benzyl, and cinnamyl acetate esters obtained in the batch conditions were 80, 81, and 83%, respectively. Whereas on adopting a simple distillation technique, these yields were successfully improved to higher values of 97, 98, and 90%, respectively. Experimental results manifested that the reaction followed Langmuir–Hinshelwood mechanism. Finally, the catalyst could be completely recycled without loss of its activity after four cycles of the esterification reactions.
A ZEOLITE CATALYST AND USE THEREOF FOR THE DEHYDROGENATION OF ALKANES
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Page/Page column 29-31, (2022/02/05)
The present invention relates to a zeolite catalyst, wherein the zeolite catalyst comprises a zeolitic material, wherein the framework of the zeolitic material comprises Y02 and X203, wherein Y is a tetravalent element and X is a trivalent element, wherein the Y : X molar ratio of Y and X contained in the framework of the zeolitic material is comprised in the range of from 500 to 10,000, and wherein the zeolite catalyst further comprises Pt which is supported on the zeolitic material. Furthermore, the present invention relates to a molding comprising the zeolite catalyst, as well as to processes for the preparation of the molding. The present invention also relates to a process for the dehydrogenation of alkanes using the inventive zeolite catalyst or molding, as well as to their respective use. In particular, the catalyst can be Pt/ZSM-5, Pt-Zn/ZSM-5, Pt-K/ZSM-5 or Pt-Zn-K / ZSM-5, with the zeolite exhibiting a Si/A I molar ratio of 850.
TfO-···H-O-H Interaction-Assisted Generation of a Silicon Cation from Allylsilanes: Access to Phenylallyl Ferrier Glycosides from Glycals
Addanki, Rupa Bai,Halder, Suvendu,Kancharla, Pavan K.
supporting information, p. 1465 - 1470 (2022/02/23)
We demonstrate here that the strained and bulky protonated 2,4,6-tri-tert-butylpyridine (TTBPy) triflate salt serves as a mild and efficient organocatalyst for the diastereoselective C-Ferrier glycosylation of various glycals. The importance of the role of the 1/2 H2O molecule trapped in the catalyst has been disclosed. The mechanism of action involves unique anionic triflate and H2O hydrogen-bond interactions that assist the activation of allylsilanes, providing unprecedented access to diastereoselective phenylallyl Ferrier glycosides.
Investigation on the Thermal Cracking and Interaction of Binary Mixture of N-Decane and Cyclohexane
Chen, Xuejiao,Pang, Weiqiang,Wang, Bo,Zhang, Ziduan,Zhou, Lingxiao,Zhu, Quan
, (2022/03/02)
Abstract: The investigation about the thermal cracking performance and interaction of different components in hydrocarbon fuels is of great significance for optimizing the formulation of high-performance hydrocarbon fuels. In this work, thermal cracking of n-decane, cyclohexane and their binary mixture were studied in a tubular reactor under different temperatures and pressures. The gas and liquid products were analyzed in detail with different gas chromatography. The main gas products of pure n-decane and cyclohexane are similar, and there is a certain difference in the main liquid products. For binary mixture, the overall conversion rate and gas yield are lower than their theoretical value. The cracking conversion rate of n-decane in binary mixture is lower than that in pure n-decane, but the opposite change occurs for cyclohexane, and the effect become more obvious as the increase of the reaction pressure. These experimental phenomena can be explained by bond dissociation energy and free radical reaction mechanism. The pressure affects the free radical reaction path, and high pressure is more conducive to bimolecular hydrogen abstraction reaction, which will lead to different product content. A law of interaction between the n-decane and cyclohexane was observed according to the experimental results. [Figure not available: see fulltext.]
Impact of composition and structural parameters on the catalytic activity of MFI type titanosilicalites
Bruk, Lev,Chernyshev, Vladimir,Khramov, Evgeny,Kravchenko, Galina,Kustov, Aleksander,Kustov, Leonid,Kuz'Micheva, Galina,Markova, Ekaterina,Pastukhova, Zhanna,Pirutko, Larisa
, p. 3439 - 3451 (2022/03/14)
Titanosilicalite of the MFI type was obtained via a hydrothermal method. Its initial and annealed at 75 °C (TS-1P(75)) and 500 °C (TS-1P(500)) forms were studied by X-ray powder diffraction (PXRD), X-ray absorption spectroscopy (XAS-method), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), temperature-programmed ammonia desorption (TPD NH3), and pyridine adsorption (Py). The full-profile Rietveld method allowed us to observe the presence of the organic template tetrapropylammonium hydroxide (TPAOH) in the framework voids, as well as to determine the silicate module (Si/Ti = 73.5) and the distribution of Ti4+ ions over the MFI-type structure sites (Ti atoms replace Si ones in two positions: T1 and T6). The coordination numbers of titanium (CNTi = 4.6 for TS-1P and TS-1P(75), CNTi = 3.8 for TS-1P(500)) were established by the XAS-method. The catalytic activity of titanosilicalites was found in the reactions of nitrous oxide decomposition (the maximal decomposition rate is demonstrated for the TS-1P(75) sample), allyl chloride epoxidation to epichlorohydrin (the best combination of all indicators was exhibited for the TS-1P sample) and propane conversion (maximum propane conversion, and butadiene and propylene selectivity were observed in both TS-1P(75) and TS-1P(500) samples). Mechanisms for the catalytic processes are proposed. The relationship between the catalytic properties and the composition (Si/Ti), Ti4+ ion distribution over the MFI-type structure sites, the local environment of titanium ions, and the number of acid sites in the titanosilicalites are discussed.
MWW TYPE ZEOLITE, METHOD FOR PRODUCING SAME, AND CRACKING CATALYST
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Paragraph 0142-0144, (2021/01/21)
Provided are the following: an MWW type zeolite which has many Br?nsted acid sites when in the form of a proton type and which is highly suitable as a cracking catalyst for cumene; a method for producing same; and an application of same. The present invention provides an MWW type zeolite in which the ratio (B/A) of the peak intensity (B) attributable to tetracoordinate aluminum relative to the peak intensity (A) attributable to hexacoordinate aluminum is 2 or more in 27Al MAS NMR, when measured as an ammonium type. The present invention also provides a method for producing an MWW type zeolite, the method having a step for carrying out a hydrothermal synthesis reaction in the presence of: a seed crystal of an MWW type zeolite containing no organic structure-directing agent; and a reaction mixture containing a silica source, an alumina source, an alkali source, an organic structure-directing agent, and water. The reaction mixture satisfies the following molar ratio: X/SiO20.15 (here, X denotes the number of moles of the organic structure-directing agent).
Selective Preparation of Olefins through Conversion of C2 and C3 Alcohols on NASICON-Type Phosphates
Ermilova, M. M.,Il’in, A. B.,Orekhova, N. V.,Yaroslavtsev, A. B.
, p. 693 - 700 (2021/07/26)
Abstract—: We have studied the catalytic activity of LiZr2(PO4)3-based NASICON-type phosphates for conversion of C2 and C3 aliphatic alcohols with the aim of selectively preparing C2–C4 olefins. Selectivity has been controlled via partial heterovalent substitutions of In3+ or Nb5+ for Zr4+ or Mo for phosphorus. We have investigated the structure and morphology of the synthesized catalysts. The nature of the dopants has been shown to play a key role in determining the selectivity of the catalysts studied. Partial In3+ substitution for Zr4+ improves the dehydrogenating properties of the materials, whereas partial substitutions of Nb5+ for Zr4+ and Mo6+ for P5+ improve their dehydrating properties. We have demonstrated the possibility of highly selective preparation of ethylene and butylenes from ethanol and of propylene from propanol-1 and propanol-2.
Sulfonated nanoporous activated carbons for catalytic isopropyl alcohol dehydration
Grishchenko, Liudmyla M.,Yatsymyrskiy, Andrii V.,Matushko, Igor P.,Klymchuk, Dmytro O.,Mischanchuk, Oleksandr V.,Boldyrieva, Olga Yu.,Diyuk, Vitaliy E.
, p. 1 - 16 (2021/08/16)
Sulfonation of nanoporous activated carbon (NAC) was performed in the different ways available within the synthetic organic chemistry armory for preparing solid acid catalysts of isopropyl alcohol dehydration (IDH). The sulfonated NACs, with from 0.15 to 1.0 mmol of sulfo groups per gram of NAC, have good catalytic performance. Sulfonated oligo- and poly(α-methylstyrene)s grafted on the oxidized NAC exhibited superior catalytic activity and high stability in the IDH reaction. Conversion of isopropyl alcohol to propene of about 100% was achieved with these catalysts at temperatures in the range of 140–170 °C. Most catalysts obtained are active in the IDH reaction; however, we observed that the propene yield depends on the method used for the NAC sulfonation.
Bridging the Gap: From Homogeneous to Heterogeneous Parahydrogen-induced Hyperpolarization and Beyond
Chekmenev, Eduard Y.,Goodson, Boyd M.,Bukhtiyarov, Valerii I.,Koptyug, Igor V.
, p. 710 - 715 (2021/04/14)
Demonstration of parahydrogen-induced polarization effects in hydrogenations catalyzed by heterogeneous catalysts instead of metal complexes in a homogeneous solution has opened an entirely new dimension for parahydrogen-based research, demonstrating its applicability not only for the production of catalyst-free hyperpolarized liquids and gases and long-lived non-equilibrium spin states for potential biomedical applications, but also for addressing challenges of modern fundamental and industrial catalysis including advanced mechanistic studies of catalytic reactions and operando NMR and MRI of reactors. This essay summarizes the progress achieved in this field by highlighting the research contributed to it by our colleague and friend Kirill V. Kovtunov whose scientific career ended unexpectedly and tragically at the age of 37. His role in this research was certainly crucial, further enhanced by a vast network of his contacts and collaborations at the national and international level.
