89-79-2Relevant academic research and scientific papers
Fe-Modified Zeolite BETA as an Active Catalyst for Intramolecular Prins Cyclization of Citronellal
Vrbková, Eva,Prejza, Tomá?,Lhotka, Miloslav,Vysko?ilová, Eli?ka,?erveny, Libor
, p. 1993 - 2003 (2021)
Abstract: Prins intramolecular cyclization of citronellal giving desired product isopulegol was performed using different modified zeolites BETA (Si/Al ratio 25, 38 and 75 modified with iron or zinc of 1, 5 or 10?wt.% by wet impregnation method). In case of materials BETA Si/Al 38 and 75 led material impregnation with metal to increase of material catalytic activity (accompanied with increase of amount of weak acid sites detected using temperature programmed desorption). Material BETA 38 with loading 1?wt.% of Fe provided 97% citronellal conversion and 94% selectivity of isopulegol formation (90?°C, toluene, 24?h). Graphic Abstract: [Figure not available: see fulltext.]
Fluorocyclization of Unsaturated Aldehydes to Five- or Six-membered Cyclic Fluoroalcohols
Hayashi, Eiji,Hara, Shoji,Shirato, Hiroyasu,Hatekeyama, Tsuyoshi,Fukuhara, Tsuyoshi,Yoneda, Norihiko
, p. 205 - 206 (1995)
In the presence of HF-Et3N complexes, the stereoselective cyclization of 5- and 6-alkenals takes place to give five- and six-membered cyclic fluoroalcohols, respectively.
Synthesis modulation as a tool to increase the catalytic activity of metal-organic frameworks: The unique case of UiO-66(Zr)
Vermoortele, Frederik,Bueken, Bart,Le Bars, Gaelle,Van De Voorde, Ben,Vandichel, Matthias,Houthoofd, Kristof,Vimont, Alexandre,Daturi, Marco,Waroquier, Michel,Van Speybroeck, Veronique,Kirschhock, Christine,De Vos, Dirk E.
, p. 11465 - 11468 (2013)
The catalytic activity of the zirconium terephthalate UiO-66(Zr) can be drastically increased by using a modulation approach. The combined use of trifluoroacetic acid and HCl during the synthesis results in a highly crystalline material, with partial substitution of terephthalates by trifluoroacetate. Thermal activation of the material leads not only to dehydroxylation of the hexanuclear Zr cluster but also to post-synthetic removal of the trifluoroacetate groups, resulting in a more open framework with a large number of open sites. Consequently, the material is a highly active catalyst for several Lewis acid catalyzed reactions.
One-pot conversion of citronellal into isopulegol epoxide on mesoporous titanium silicate
Guidotti,Moretti,Psaro,Ravasio
, p. 1789 - 1790 (2000)
Citronellal was converted into isopulegol epoxide in a one-pot two-step reaction achieving a 68% global yield on Ti-MCM-41 and designing a two-solvent catalytic system.
Tuning the surface properties of novel ternary iron(iii) fluoride-based catalysts using the template effect of the matrix
Guo, Ying,Lippitz, Andreas,Saftien, Paul,Unger, Wolfgang E. S.,Kemnitz, Erhard
, p. 5076 - 5085 (2015)
Sol-gel prepared ternary FeF3-MgF2 materials have become promising heterogeneous catalysts due to their porosity and surface Lewis/Bronsted acidity (bi-acidity). Despite the good catalytic performance, nanoscopic characterisations of this type of material are still missing and the key factors controlling the surface properties have not yet been identified, impeding both a better understanding and further development of ternary fluoride catalysts. In this study, we characterised the interaction between the bi-acidic component (FeF3) and the matrix (MgF2) on the nano-scale. For the first time, the formation pathway of FeF3-MgF2 was profiled and the template effect of MgF2 during the synthesis process was discovered. Based on these new insights two novel materials, FeF3-CaF2 and FeF3-SrF2, were established, revealing that with decreasing the atomic numbers (from Sr to Mg), the ternary fluorides exhibited increasing surface acidity and surface area but decreasing pore size. These systematic changes gave rise to a panel of catalysts with tuneable surface and bulk properties either by changing the matrix alkaline earth metal fluoride or by adjusting their ratios to Fe or both. The template effect of the alkaline earth metal fluoride matrix was identified as the most probable key factor determining the surface properties and further influencing the catalytic performance in ternary fluoride based catalysts, and paves the way to targeted design of next-generation catalysts with tunable properties. This journal is
Continuous synthesis of menthol from citronellal and citral over Ni-beta-zeolite-sepiolite composite catalyst
Er?nen, Kari,M?ki-Arvela, P?ivi,Martinez-Klimov, Mark,Muller, Joseph,Murzin, Dmitry Yu.,Peurla, Markus,Simakova, Irina,Vajglova, Zuzana
, (2022/04/03)
One-pot continuous synthesis of menthols both from citronellal and citral was investigated over 5 wt% Ni supported on H-Beta-38-sepiolite composite catalyst at 60–70 °C under 10–29 bar hydrogen pressure. A relatively high menthols yield of 53% and 49% and stereoselectivity to menthol of 71–76% and 72–74% were obtained from citronellal and citral respectively at the contact time 4.2 min, 70 °C and 20 bar. Citral conversion noticeably decreased with time-on-stream under 10 and 15 bar of hydrogen pressure accompanied by accumulation of citronellal, the primary hydrogenation product of citral, practically not affecting selectivity to menthol. A substantial amount of defuctionalization products observed during citral conversion, especially at the beginning of the reaction (ca. 1 h), indicated that all intermediates could contribute to formation of menthanes. Ni/H-Beta-38-sepiolite composite material prepared by extrusion was characterized by TEM, SEM, XPS, XRD, ICP-OES, N2 physisorption and FTIR techniques to perceive the interrelation between the physico-chemical and catalytic properties.
Sulfonated Hyper-cross-linked Porous Polyacetylene Networks as Versatile Heterogeneous Acid Catalysts
Sekerová, Lada,B?ezinová, Pavlína,Do, Thuy Tran,Vysko?ilová, Eli?ka,Krupka, Ji?í,?erveny, Libor,Havelková, Lucie,Bashta, Bogdana,Sedlá?ek, Jan
, p. 1075 - 1084 (2020/01/03)
Two highly sulfonated micro/mesoporous polymers, P(1,3-DEB)-SO3H and P(1,4-DEB)-SO3H, with permanent porosity, the specific surface area about 550 m2 ? g?1 and the content of SO3H groups of 2.7 mmol ? g?1 were prepared as new acid Porous Polymer Catalysts, PPCs. The PPCs were achieved by easy sulfonation of parent hyper-cross-linked micro/mesoporous polyacetylene-type networks resulting from a chain-growth homopolymerization of 1,3- and 1,4-diethynylbenzenes. New PPCs are reported as highly active and reusable heterogeneous catalysts of esterification of fatty acids with methanol and ethanol, Prins cyclization of aldehydes with isoprenol and intramolecular Prins cyclization of citronellal to isopulegol. The catalytic activity of the micro/mesoporous PPCs (TON values up to 522 mol ? mol?1) was higher than that of commercial polymer-based heterogeneous catalyst Amberlyst 15 possessing gel texture without permanent pores and that of p-toluenesulfonic acid applied as a homogeneous catalyst.
Method for preparing L-menthol by adopting modified homogeneous catalyst
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Paragraph 0038-0040; 0059-0066, (2020/03/09)
The invention discloses a method for preparing L-menthol by adopting a modified homogeneous catalyst. The method comprises the following steps: preparing a modified homogeneous catalyst, preparing isopulegol, preparing D, L-menthol, and preparing L-menthol; wherein a ligand is prepared from 2, 6-dimethylpyridine and a ketone compound by using the modified homogeneous catalyst, the ligand is reacted with alkyl aluminum to obtain an organic aluminum compound, and L-menthol is prepared by chemically inducing chiral resolution of D, L-menthol. According to the method, the organic aluminum compoundis used as the catalyst of the ring-closure reaction of citronellal, so that the yield of isopulegol is increased, the selectivity on product isopulegol is high, and the used organic aluminum catalyst is easy to synthesize, high in stereoselectivity to reaction and easy to crystallize and recover; D, L-menthol is split by a chemical induction method, the method is simple to operate, the reactionyield of each step is high, the reaction conditions are stable, the product cannot be partially racemized, and the product loss is small.
Synthesis of: P-menthane-3,8-diol from citronellal over lignin-derived carbon acid catalysts
Abudula, Abuliti,Chaihad, Nichaboon,Du, Xiao,Guan, Guoqing,Hao, Xiaogang,Kurnia, Irwan,Li, Shasha,Prakoso, Tirto,Yoshida, Akihiro
supporting information, p. 10441 - 10447 (2020/07/14)
p-Menthane-3,8-diol (PMD) is receiving growing attention as a natural mosquito repellent with lower toxicity compared to the widely-used N,N-diethyl m-toluamide (DEET). In this study, sustainable carbon acid catalysts derived from alkaline lignin (AL) were prepared for synthesizing PMD from a popular chemical (±)-citronellal in an environmentally friendly solvent of water. The catalytic performances of the AL-derived carbon acid catalysts prepared at different pyrolysis temperatures were better than those of other catalysts such as carbon black and H-USY. In particular, when the AL pyrolyzed at 500 °C was used as the carbon acid catalyst, the conversion of (±)-citronellal was as high as 97% with a high PMD yield of 86%, indicating that waste alkaline lignin from pulp and paper industries can be used as a source of acid catalysts. It is found that the formation of PMD is preferred over catalysts with weaker acid sites, whereas isopulegol was more easily formed over stronger acid sites. Moreover, the reaction route of the citronellal cyclization-hydration reaction was more dominant via the carbocation-hydration pathway rather than the isopulegol hydration route on the weaker carbon acid catalyst. This journal is
Continuous flow synthesis of menthol: Via tandem cyclisation-hydrogenation of citronellal catalysed by scrap catalytic converters
Zuliani, Alessio,Cova, Camilla Maria,Manno, Roberta,Sebastian, Victor,Romero, Antonio A.,Luque, Rafael
, p. 379 - 387 (2020/02/13)
A continuous flow synthesis of menthol starting from citronellal catalysed by scrap catalytic converters is reported. The reaction was conducted in a tandem system connecting in series two catalytic systems, with the first having Lewis acid properties (favouring the cyclisation of citronellal to isopulegols) and the second having hydrogenation catalytic activity (catalysing the hydrogenation of isopulegols to menthols). A Lewis acid catalyst was prepared by supporting iron oxide nanoparticles over a waste material, i.e. the ceramic core of scrap catalytic converters (SCATs) via a microwave assisted method. Most importantly, SCATs, containing a low residual noble metal content, could be directly employed in the second step as hydrogenation catalysts. The reaction was performed studying the influence on the yield and selectivity to (-)-menthol of various reaction parameters (T, p and flow rate). Under the best reaction conditions (at a flow rate of 0.1 mL min-1 and at 373 K and 413 K for cyclisation and hydrogenation steps respectively) a conversion of >99% of (+)-citronellal to (-)-menthol with 77% final yield was achieved.
