scholarly journals Highly selective synthesis of citronellal in water at multigram scale by Pd nanoparticles-catalyzed hydrogenation of citral

2021 ◽  
Author(s):  
DUVAL Marion ◽  
SAGORIN Gilles ◽  
Audrey Denicourt-Nowicki ◽  
Alain ROUCOUX
Keyword(s):  
Double Bond ◽  
Palladium Nanoparticles ◽  
Potassium Hydroxide ◽  
Pd Nanoparticles ◽  
Added Value ◽  
Selective Synthesis ◽  
Complete Conversion ◽  
Turnover Number ◽  
Reaction Conditions ◽  
Excellent Selectivity

The synthesis of citronellal, an added-value chemical for perfumery, was carried out by selective and green hydrogenation of citral into citronellal in water. Aqueous suspensions of spherical ammonium-capped palladium nanoparticles with sizes around 3nm selectively reduced the conjugated carbon-carbon double bond. An excellent selectivity of 95% in citronellal was achieved at complete conversion under mild reaction conditions on a realistic 2 g scale in water. The presence of potassium hydroxide proved crucial to control the selectivity and avoid other hydrogenation co-products. These optimized results were further extended to a 135 g substrate loading with a relevant turnover number (TON) of 10 000.

scholarly journals Pd Nanoparticles and Mixture of CO2/CO/O2 Applied in the Carbonylation of Aniline

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 877 ◽  
Author(s):  
Dominik Madej ◽  
Adrian Konopko ◽  
Piotr Piotrowski ◽  
Agnieszka Krogul-Sobczak
Keyword(s):  
Reaction Time ◽  
Palladium Nanoparticles ◽  
High Stability ◽  
Pd Nanoparticles ◽  
Active Species ◽  
Catalytic Cycle ◽  
Aliphatic Amines ◽  
Pyridine Ligand ◽  
Reaction Conditions ◽  
Derivatives Of

CO2 is a compound of high stability which proves useful in some organic syntheses as a solvent or component decreasing explosivity of gases. It is also a good carbonylating agent for aliphatic amines although not for aromatic ones, the latter being carbonylated with phosgene or, as in our previous works, with CO/O2 in the presence of Pd(II) complexes. In this work we have used the mixture of CO/O2 and CO2 for carbonylation of aniline to N,N’-diphenylurea. After optimization of the reaction conditions (56% of CO2 in CO2/CO mixture) we studied the activity of three kinds of pre-catalysts: (a) Pd(II) complexes, (b) Pdblack, and (c) palladium nanoparticles (PdNPs) in the presence of derivatives of pyridine (XnPy). The highest conversion of aniline (with selectivity towards N,N-diphenylurea ca. 90%) was observed for PdNPs. The results show that catalytic cycle involves Pd(0) stabilized by pyridine ligand as active species. Basing on this observation, we put the hypothesis that application of PdNPs instead of Pd(II) complex can efficiently reduce the reaction time.

scholarly journals Vicinal difunctionalization of carbon–carbon double bond for the platform synthesis of trifluoroalkyl amines

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ferenc Béke ◽  
Ádám Mészáros ◽  
Ágnes Tóth ◽  
Bence Béla Botlik ◽  
Zoltán Novák
Keyword(s):  
Double Bond ◽  
Transition Metal ◽  
High Efficiency ◽  
Chemical Nature ◽  
Synthetic Approach ◽  
Selective Synthesis ◽  
Reaction Conditions ◽  
Metal Free ◽  
Amine Compounds ◽  
Broad Scale

AbstractRegioselective vicinal diamination of carbon–carbon double bonds with two different amines is a synthetic challenge under transition metal-free conditions, especially for the synthesis of trifluoromethylated amines. However, the synthesis of ethylene diamines and fluorinated amine compounds is demanded, especially in the pharmaceutical sector. Herein, we demonstrate that the controllable double nucleophilic functionalization of an activated alkene synthon, originated from a trifluoropropenyliodonium salt with two distinct nucleophiles, enables the selective synthesis of trifluoromethylated ethylene amines and diamines on broad scale with high efficiency under mild reaction conditions. Considering the chemical nature of the reactants, our synthetic approach brings forth an efficient methodology and provides versatile access to highly fluorinated amines.

Selective Semi-Hydrogenation of Terminal Alkynes Promoted by Bimetallic Cu-Pd Nanoparticles

Synthesis ◽  
2018 ◽  
Vol 51 (06) ◽  
pp. 1466-1472 ◽  
Author(s):  
Gabriel Radivoy ◽  
Eduardo Buxaderas ◽  
María Volpe
Keyword(s):  
Thermal Treatment ◽  
Palladium Nanoparticles ◽  
Weight Ratio ◽  
Pd Nanoparticles ◽  
Terminal Alkynes ◽  
Reaction Conditions ◽  
Mesostructured Silica ◽  
Bimetallic Nanocatalyst

The selective semi-hydrogenation of terminal alkynes was efficiently performed, under mild reaction conditions (H2 balloon, 110 °C), promoted by a bimetallic nanocatalyst composed of copper and palladium nanoparticles (5:1 weight ratio) supported on mesostructured silica (MCM-48). The Cu-PdNPS@MCM-48 catalyst, which demonstrated to be highly chemoselective towards the alkyne functionality, is readily prepared from commercial materials and can be recovered and reused after thermal treatment followed by reduction under H2 atmosphere.

scholarly journals Sustainable Approaches to the Synthesis of Metallophthalocyanines in Solution

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1760
Author(s):  
Gloria Zanotti ◽  
Patrizia Imperatori ◽  
Anna Maria Paoletti ◽  
Giovanna Pennesi
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Potassium Hydroxide ◽  
Production Cost ◽  
Added Value ◽  
Reaction Conditions ◽  
Transition Metal Cations ◽  
Tert Butyl ◽  
Whole Process ◽  
Reaction Media

This work aims to investigate more sustainable reaction conditions for the synthesis of metallophthalocyanines. Anisole, glycerol and their mixtures have been investigated as reaction media for the tetramerization of phthalonitriles. Acetates of three divalent first-transition metal cations, Co(II), Cu(II) and Zn(II), were used and several bases were tested, depending on the chosen substrates and reaction conditions, with a view to making the whole process more sustainable while ensuring its scalability. Unsubstituted phthalocyanines were synthesized to analyze the behavior of the different metal ions in terms of reactivity in the new reaction media, resulting in a general Cu > Co > Zn trend, while the nonpolar tetra-tert-butyl substitution was investigated to evaluate the synthesis of soluble derivatives in the new conditions. Furthermore, the potassium hydroxide (KOH)-aided statistical synthesis of the unsymmetrical 9(10), 16(17), 23(24)-tri-tert-butyl-2-iodophthalocyaninato zinc(II), starting from 4-tert-butylphthalonitrile and 4-iodophthalonitrile in a glycerol/anisole mixture, proceeded with a satisfactory 26% yield. Our results provide insights into the investigation of new reaction environments and the understanding of their strengths and weaknesses, with a view to further increasing the sustainability of the synthesis of metallomacrocycles with high added value while lowering their production cost.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

Some Analogs of 4-(2',4'-Difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic Acid: Synthesis and Antiinflammatory Activity

1995 ◽  
Vol 60 (6) ◽  
pp. 1026-1033 ◽  
Author(s):  
Miroslav Kuchař ◽  
Václav Vosátka ◽  
Marie Poppová ◽  
Eva Knězová ◽  
Vladimíra Panajotovová ◽  
...  
Keyword(s):  
Double Bond ◽  
Antiinflammatory Activity ◽  
Acid Synthesis ◽  
Reaction Conditions ◽  
Methyl Group ◽  
Oxobutanoic Acid

Analogs of 4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid (I, flobufen), containing a double bond (II, IV, V, VII, VIII) or a methyl group in position 3 (VI) were prepared. Their antiinflammatory activity was evaluated and compared with that of flobufen. None of the mentioned analogs reached the activity of the standard. Isomerization of the unsaturated derivatives is connected with a shift of the double bond, Z-E transformation or lactonization. Reaction conditions and spectra of the compounds prepared are described.

π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position

2002 ◽  
Vol 67 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Petr Melša ◽  
Ctibor Mazal
Keyword(s):  
Double Bond ◽  
Carboxylic Acid ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure ◽  
Nitrile Imine ◽  
Facial Selectivity ◽  
Excellent Selectivity

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.

Size-dependent Hydrogen trapping in Palladium nanoparticles

2021 ◽  
Author(s):  
Wang Liu ◽  
Yann Magnin ◽  
Georg Daniel Förster ◽  
Julie Bourgon ◽  
Thomas Len ◽  
...  
Keyword(s):  
Experimental Study ◽  
Theoretical Approach ◽  
Palladium Nanoparticles ◽  
Hydrogen Absorption ◽  
Pd Nanoparticles ◽  
Hydrogen Trapping ◽  
Size Dependent

We report an experimental study, supported by a theoretical approach based on simulations, to explore the phenomenon of H trapping in small Pd nanoparticles. Hydrogen absorption/desorption of a series of...

scholarly journals Delignification of Cistus ladanifer Biomass by Organosolv and Alkali Processes

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1127
Author(s):  
Júnia Alves-Ferreira ◽  
Ana Lourenço ◽  
Francisca Morgado ◽  
Luís C. Duarte ◽  
Luísa B. Roseiro ◽  
...  
Keyword(s):  
Steam Distillation ◽  
Enzymatic Saccharification ◽  
Added Value ◽  
Cistus Ladanifer ◽  
Reaction Conditions ◽  
Zone Electrophoresis ◽  
Monomeric Composition ◽  
Capillary Zone ◽  
Soluble Lignin ◽  
Pretreated Biomass

Residues of Cistus ladanifer obtained after commercial steam distillation for essential oil production were evaluated to produce cellulose enriched solids and added-value lignin-derived compounds. The delignification of extracted (CLRext) and extracted and hydrothermally pretreated biomass (CLRtreat) was studied using two organosolv processes, ethanol/water mixtures (EO), and alkali-catalyzed glycerol (AGO), and by an alkali (sodium hydroxide) process (ASP) under different reaction conditions. The phenolic composition of soluble lignin was determined by capillary zone electrophoresis and by Py-GC/MS, which was also used to establish the monomeric composition of both the delignified solids and isolated lignin. The enzymatic saccharification of the delignified solids was also evaluated. The ASP (4% NaOH, 2 h) lead to both the highest delignification and enzymatic saccharification (87% and 79%, respectively). A delignification of 76% and enzymatic hydrolysis yields of 72% were obtained for AGO (4% NaOH) while EO processes led to lower delignification (maximum lignin removal 29%). The residual lignin in the delignified solids were enriched in G- and H-units, with S-units being preferentially removed. The main phenolics present in the ASP and AGO liquors were vanillic acid and epicatechin, while gallic acid was the main phenolic in the EO liquors. The results showed that C. ladanifer residues can be a biomass source for the production of lignin-derivatives and glucan-rich solids to be further used in bioconversion processes.

scholarly journals Synthesis of monodisperse Pd nanoparticles using a binary surfactant combination and sodium oleate as reductant

2021 ◽  
Author(s):  
Anna Pekkari ◽  
Xin Wen ◽  
Jessica Orrego Hernandez ◽  
Robson Rosa da Silva ◽  
Shun Kondo ◽  
...  
Keyword(s):  
Sodium Oleate ◽  
Palladium Nanoparticles ◽  
Pd Nanoparticles

Palladium nanoparticles (NPs) are relevant for a broad range of applications such as sensing and catalysis. This study presents the synthesis of monodisperse Pd nanoparticles (NPs) stabilized by sodium oleate...

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