122-40-7Relevant articles and documents
An amino-modified Zr-terephthalate metal-organic framework as an acid-base catalyst for cross-aldol condensation
Vermoortele, Frederik,Ameloot, Rob,Vimont, Alexandre,Serre, Christian,De Vos, Dirk
, p. 1521 - 1523 (2011)
After controlled pretreatment, some Zr-terephthalate metal-organic frameworks are highly selective catalysts for the cross-aldol condensation between benzaldehyde and heptanal. The proximity of Lewis acid and base sites in the amino-functionalized UiO-66(NH2) material further raises the reaction yields.
Hierarchical high-silica zeolites as superior base catalysts
Keller, Tobias C.,Isabettini, Stephane,Verboekend, Danny,Rodrigues, Elodie G.,Perez-Ramirez, Javier
, p. 677 - 684 (2014)
For more than four decades, the design of zeolite base catalysts has relied on the application of aluminium-rich frameworks exchanged with alkali metal cations (preferably Cs+). However, moderate activity associated with access and diffusion limitations, and high manufacturing costs associated with high caesium content (typically over 30%) have hampered their industrial implementation so far. Herein, we have discovered that high-silica USY zeolites outperform their Al-rich counterparts in a variety of base-catalysed reactions of relevance in the fine chemical industry, as well as in the upgrading of biofuels. The benefits of this class of materials are amplified upon the alleviation of diffusion constraints through the introduction of a network of intracrystalline mesopores by post-synthetic modification. For example, the resulting cation-free hierarchical USY provides an up to 30-fold Knoevenagel condensation activity compared to the benchmark Cs-X, and similar observations were made upon application in liquid-phase (nitro)aldol reactions. Moreover, in the gas-phase aldol condensation of propanal, high-silica zeolites provide superior activity, selectivity, and lifetime compared to caesium-containing zeolites and even a strong solid base such as MgO. We decouple the complex interplay between mesoporosity and intrinsic zeolitic properties such as crystallinity, and quantify the increase in catalyst effectiveness upon hierarchical structuring as a function of reactant size. The obtained results are a major step to resolve the drawbacks of zeolites catalysis and thereby revitalise their potential for industrial application.
Reconstructed Mg/Al hydrotalcite as a solid base catalyst for synthesis of jasminaldehyde
Sharma, Sumeet K.,Parikh, Parimal A.,Jasra, Raksh V.
, p. 34 - 42 (2010)
Reconstructed hydrotalcites (Mg/Al molar ratio = 3.5) of varied reconstruction time were synthesized and used as catalysts for solvent free condensation of 1-heptanal with benzaldehyde. Maximum conversion of 1-heptanal with higher selectivity to jasminaldehyde was obtained using reconstructed hydrotalcites of 8-12 h reconstruction time. Catalytic activity of reconstruction hydrotalcite was compared with as-synthesized and activated hydrotalcite of Mg/Al molar ratio 3.5 and significantly higher conversion of 1-heptanal was observed in case of reconstructed hydrotalcite of 8 h reconstruction time as a catalyst. Similar to the conversion, higher selectivity to jasminaldehyde was also obtained using reconstructed hydrotalcite. Effect of reconstruction time on conversion and selectivity to jasminaldehyde was studied by varying the reconstruction time of hydrotalcite from 0.5 to 72 h. Kinetic experiments were carried out to study the effect of stirring speed, benzaldehyde to 1-heptanal molar ratio, amount of catalyst and reaction temperature on the rate of reaction using reconstructed hydrotalcite as a catalyst.
Decoration of chitosan microspheres with inorganic oxide clusters: Rational design of hierarchically porous, stable and cooperative acid-base nanoreactors
Kadib, Abdelkrim El,Molvinger, Karine,Bousmina, Mosto,Brunel, Daniel
, p. 147 - 155 (2010)
One of the fundamental enzymatic catalyst assets, which is the most difficult to engineer in synthetic systems, is the coexistence of multifunctional sites and their synergetic cooperation. In this work, an efficient approach toward cooperative acid-base materials using natural matrices is proposed. Taking advantages from chitosan polysaccharide as nano-assembling system and on the supercritical drying technique to preserve their porosity, the mutual interactions between different glucosamine units and the Lewis acidic precursors (Ti, Zr, Al, Sn) allowed the preparation of hierarchically porous microspheres in which well-separated amino groups from chitosan are replicated with highly dispersed acidic inorganic oxides. This decoration at the nano-scale entails a notable improvement on the hydrothermal stability of the resulting organic-inorganic hybrid materials. The resulting acid-base hybrid materials are assessed for three carbon-carbon forming reactions (Henry condensation, Michael addition and jasminaldehyde synthesis) and systematically compared to the pure acidic inorganic oxide and basic chitosan microspheres. The bifunctional materials displayed interesting catalytic activity and selectivity, with respect to monofunctional ones, witnessing thus on the cooperative effect attainable in chitosan@inorganic oxide microspheres.
Synthesis of jasminaldehyde by solid-liquid phase transfer catalysis without solvent, under microwave irradiation
Abenhaim,Ngoc Son,Loupy,Ba Hiep
, p. 1199 - 1205 (1994)
α-n-amylcinnamaldehyde (jasminaldehyde) was obtained with 82% yield by solid-liquid phase transfer catalysis without solvent within 3 days at room temperature. By use of domestic microwave irradiation, the same yield was obtained within 1 minute at a power of 600 W.
Amorphous metal-aluminophosphate catalysts for aldol condensation of n-heptanal and benzaldehyde to jasminaldehyde
Hamza,Nagaraju
, p. 209 - 215 (2015)
Amorphous aluminophosphate (AlP) and metal-aluminophosphates (MAlPs, where M = 2.5 mol% Cu, Zn, Cr, Fe, Ce, or Zr) were prepared by coprecipitation method. Their surface properties and catalytic activity for the synthesis of jasminaldehyde through the aldol condensation of n-heptanal and benzaldehyde were investigated. The nitrogen adsorption-desorption isotherms showed that the microporosity exhibited by the aluminophosphate was changed to a mesoporous and macroporous structure which depended on the metal incorporated, with a concomitant change in the surface area. Temperature-programmed desorption of NH3 and CO2 revealed that the materials possessed both acidic and basic sites. The acidic strength of the material was either increased or decreased depending on the nature of the metal. The basicity was increased compared to AlP. All the materials were X-ray amorphous and powder X-ray diffraction studies indicated the absence of metal oxide phases. The Fourier transform infrared analysis confirmed the presence of phosphate groups and also the absence of any M-O moieties in the materials. The selected organic reaction occurred only in the presence of the AlP and MAlPs. The selectivity for the jasminaldehyde product was up to 75% with a yield of 65%. The best conversion of n-heptanal with a high selectivity to jasminaldehyde was obtained with FeAlP as the catalyst, and this material was characterized to have less weak acid sites and more basic sites.
Design and synthesis of chitin synthase inhibitors as potent fungicides
Chen, Qi,Zhang, Ji-Wei,Chen, Lu-Lu,Yang, Jun,Yang, Xin-Ling,Ling, Yun,Yang, Qing
, p. 1232 - 1237 (2017/06/19)
Chitin is a structural component of fungal cell walls but is absent in vertebrates, mammals, and humans. Chitin synthase is thus an attractive molecular target for developing fungicides. Based on the structure of its donor substrate, UDP-N-acetyl-glucosamine, as well as the modelled structure of the bacterial chitin synthase NodC, we designed a novel scaffold which was then further optimized into a series of chitin synthase inhibitors. The most potent inhibitor, compound 13, exhibited high chitin synthase inhibitory activity with an IC50 value of 64.5?μmol/L. All of the inhibitors exhibited antifungal activities against the growth of agriculturally-destructive fungi, Fusarium graminearum, Botrytis cinerea, and Colletotrichum lagenarium. This work presents a new scaffold which can be used for the development of novel fungicides.
Bifunctional organocatalysts for the synthesis of jasminaldehyde and their derivatives
Ganga, Venkata Subba Rao,Abdi, Sayed H.R.,Kureshy, Rukhsana I.,Khan, Noor-Ul H.,Bajaj, Hari C.
, p. 950 - 955 (2017/08/04)
L-Proline in the presence of benzoic acid is found to be an effective catalytic system for the cross-aldol condensation of benzaldehyde with 1-heptanal under solvent free condition amongst the several amino acids screened for this reaction. Under the optimized reaction conditions, the desired product (e.g. jasminaldehyde) is formed up to 96% selectivity in one hour using the desired arylaldehyde: 1-alkanaldehyde ratio as low as 2:1 under controlled addition of 1-alkanaldehyde.
