35836-73-8Relevant articles and documents
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Arnold,Danzig
, p. 892 (1957)
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On the synergistic catalytic properties of bimetallic mesoporous materials containing aluminum and zirconium: The prins cyclisation of citronellal
Telalovic, Selvedin,Ramanathan, Anand,Ng, Jeck Fei,Maheswari, Rajamanickam,Kwakernaak, Cees,Soulimani, Fouad,Brouwer, Hans C.,Chuah, Gaik Khuan,Weckhuysen, Bert M.,Hanefeld, Ulf
, p. 2077 - 2088 (2011)
Bimetallic three-dimensional amorphous mesoporous materials, Al-Zr-TUD-1 materials, were synthesised by using a surfactant-free, one-pot procedure employing triethanolamine (TEA) as a complexing reagent. The amount of aluminium and zirconium was varied in order to study the effect of these metals on the Bronsted and Lewis acidity, as well as on the resulting catalytic activity of the material. The materials were characterised by various techniques, including elemental analysis, X-ray diffraction, high-resolution TEM, N2 physisorption, temperature-programmed desorption (TPD) of NH3, and 27Al MAS NMR, XPS and FT-IR spectroscopy using pyridine and CO as probe molecules. Al-Zr-TUD-1 materials are mesoporous with surface areas ranging from 700-900am2 g-1, an average pore size of around 4anm and a pore volume of around 0.70acm3 g -1. The synthesised Al-Zr-TUD-1 materials were tested as catalyst materials in the Lewis acid catalysed Meerwein-Ponndorf-Verley reduction of 4-tert-butylcyclohexanone, the intermolecular Prins synthesis of nopol and in the intramolecular Prins cyclisation of citronellal. Although Al-Zr-TUD-1 catalysts possess a lower amount of acid sites than their monometallic counterparts, according to TPD of NH3, these materials outperformed those of the monometallic Al-TUD-1 as well as Zr-TUD-1 in the Prins cyclisation of citronellal. This proves the existence of synergistic properties of Al-Zr-TUD-1. Due to the intramolecular nature of the Prins cyclisation of citronellal, the hydrophilic surface of the catalyst as well as the presence of both Bronsted and Lewis acid sites synergy could be obtained with bimetallic Al-Zr-TUD-1. Besides spectroscopic investigation of the active sites of the catalyst material a thorough testing of the catalyst in different types of reactions is crucial in identifying its specific active sites.
Exploring the effect of acid modulators on MIL-101 (Cr) metal-organic framework catalysed olefin-aldehyde condensation: A sustainable approach for the selective synthesis of nopol
Kalidindi, Suresh Babu,Kanakikodi, Kempanna S.,Kulkarni, Bhavana B.,Maradur, Sanjeev P.,Rambhia, Dheer A.
supporting information, p. 726 - 738 (2022/01/22)
The development of efficient and sustainable strategies that evade the utilization of petroleum reserves is highly challenging yet inevitable today. In this regard, the conversion of pine tree-derived β-pinene to highly recognized nopol is particularly attractive owing to its widespread applications. Herein, we describe an approach that enables the selective synthesis of nopol based on the extraordinary activity of MIL-101(Cr). This remarkable activity of MIL-101(Cr) is attributed to its high specific surface area (SSA), accessible active sites in the mesopore architecture and unsaturated Cr3+ Lewis acid sites. We have established a good correlation between the superior catalytic performance and textural properties of the materials, which can be tuned by using different mineralizing agents. To realize the unprecedented catalytic activity, the influence of reaction parameters, solvent properties, and mineralizing agents has been investigated systematically. MIL-101(AA) (AA-acetic acid) showed the highest catalytic activity, which is superior to most of the reported materials for this transformation to date. The results of catalyst recycling and hot filtration experiments have emphasized that the catalyst is resistant towards leaching of active sites and retained its original catalytic activity beyond four recycles. An Eley-Rideal based model was used to study the reaction kinetics and establish a plausible reaction mechanism. The activation energy of the reaction was found to be 102 kJ mol-1 and the enthalpy of formaldehyde adsorption was -86.88 kJ mol-1. This approach opens up new avenues for the valorization of biomass-based molecules into useful chemicals.
One-Pot Absolute Stereochemical Identification of Alcohols via Guanidinium Sulfate Crystallization
Brummel, Beau R.,Lee, Kinsey G.,McMillen, Colin D.,Kolis, Joseph W.,Whitehead, Daniel C.
, p. 9622 - 9627 (2019/12/02)
A novel technique for the absolute stereochemical determination of alcohols has been developed that uses crystallization of guanidinium salts of organosulfates. The simple one-pot, two-step process leverages facile formation of guandinium organosulfate single crystals for the straightforward determination of the absolute stereochemistry of enantiopure alcohols by means of X-ray crystallography. The strong hydrogen bonding network drives the stability of the crystal lattice and allows for a diverse range of organic alcohol substrates to be analyzed.
