AgNPs encapsulated by an amine-functionalized polymer nanocatalyst for CO2 fixation as a carboxylic acid and the oxidation of cyclohexane under ambient conditions

2020 ◽  
Vol 44 (14) ◽  
pp. 5448-5456 ◽  
Author(s):  
Noor Salam ◽  
Priyanka Paul ◽  
Swarbhanu Ghosh ◽  
Usha Mandi ◽  
Aslam Khan ◽  
...  

A novel catalyst comprising Ag NPs grafted to a porous polystyrene material was synthesized for the production of valuable propiolic acid derivatives via CO2 (1 atm) incorporation, and the oxidation of cyclohexane under ambient reaction conditions.

2019 ◽  
Vol 43 (22) ◽  
pp. 8669-8676 ◽  
Author(s):  
Dharmesh J. Shah ◽  
Anuj S. Sharma ◽  
Akshara P. Shah ◽  
Vinay S. Sharma ◽  
Mohd Athar ◽  
...  

Silver nanoparticles supported on microcrystalline cellulose (Ag NPs@MCC), an active catalyst, has been discovered for the direct carbonylation of terminal alkynes with CO2 into carboxylic acid under mild and sustainable reaction conditions.


2019 ◽  
Author(s):  
Jiang Wang ◽  
Brian P. Cary ◽  
Peyton Beyer ◽  
Samuel H. Gellman ◽  
Daniel Weix

A new strategy for the synthesis of ketones is presented based upon the decarboxylative coupling of N-hydroxyphthalimide (NHP) esters with S-2-pyridyl thioesters. The reactions are selective for the cross-coupled product because NHP esters act as radical donors and the thioesters act as acyl donors. The reaction conditions are general and mild, with over 40 examples presented, including larger fragments and the 20-mer peptide Exendin(9-39) on solid support.


Author(s):  
Katharina A. E. Meyer ◽  
Arman Nejad

The cis–trans-isomerism of the propiolic acid monomer (HCC–COOH) is examined with linear Raman jet spectroscopy, yielding the first environment-free vibrational band centres of a higher-energy cis-rotamer beyond formic acid (HCOOH) in addition to all fundamentals and a large number of hot and combination/overtone bands of the trans-conformer.


2016 ◽  
Vol 18 (17) ◽  
pp. 4611-4615 ◽  
Author(s):  
Shiyao Liu ◽  
Naoki Suematsu ◽  
Keiji Maruoka ◽  
Seiji Shirakawa

An efficient synthesis of cyclic carbonates from epoxides and CO2 under mild reaction conditions was achieved via the use of a designed bifunctional quaternary phosphonium iodide catalyst.


Synlett ◽  
2020 ◽  
Vol 32 (01) ◽  
pp. 45-50
Author(s):  
Udo Nubbemeyer ◽  
Analuisa Nava ◽  
Lukas Trippe ◽  
Andrea Frank ◽  
Lars Andernach ◽  
...  

AbstractStarting from methyl cycloheptatrienyl-1-carboxylate, 6-acylation was successfully achieved employing glutaryl chloride in the presence of AlCl3 under controlled reaction conditions to furnish keto carboxylic acid product. After protection of this keto carboxylic acid as tert-butyl ester, reagent-controlled enantioselective reductions delivered configuration-defined methyl-6-hydroxylalkyl cycloheptatriene-1-carboxylates with up to 80% ee. Whereas simple NaBH4 reduction of the keto carboxylic acid and subsequent lactonization afforded a methyl-6-tetrahydropyranonyl cycloheptatriene-1-carboxylate. Resolution using chiral HPLC delivered the product enantiomers with up to >99% ee Finally, ECD analyses enabled structure elucidation. The products are used as key intermediates in enantioselective 6,11-methylene-lipoxin B4 syntheses.


1997 ◽  
Vol 481 ◽  
Author(s):  
Michael F. Bell ◽  
Georges Dénès ◽  
Zhimeng Zhu

ABSTRACTPrecipitation reactions from aqueous solutions of calcium nitrate and tin(II) fluoride result in the formation of two metastable phases, depending on the reaction conditions. Crystalline CaSn2F6 and the microcrystalline Ca1-xSnxF2 solid solution are obtained, the latter crystallizing in the cubic fluorite (CaF2) type with total Ca/Sn disorder. Both phases are fluoride ion conductors. Electrical conductivity measurements versus temperature and bulk density measurements show that both phases are far from thermodynamic equilibrium at ambient conditions, and thus are metastable. Both decompose to a mixture of SnF2 and CaF2 at high temperature. In addition, CaSn2F6 is chemically unstable in an aqueous medium, in which it looses SnF2 to give the microcrystalline Ca1-xSnxF2 solid solution.


2020 ◽  
Vol 61 (23) ◽  
pp. 151966 ◽  
Author(s):  
Nam-Kyun Kim ◽  
Hiromitsu Sogawa ◽  
Toshikazu Takata

2011 ◽  
Vol 284-286 ◽  
pp. 2374-2379 ◽  
Author(s):  
Shui Jin Yang ◽  
Yong Kui Huang ◽  
Li Yu

A novel catalyst, H4SiW12O40/SiO2was synthesized by a sol-gel technique, and characterized by FT-IR and XRD. Catalytic application of H4SiW12O40/SiO2for synthesis of acetals and ketals were tested. The variation of different reaction parameters, such as mole ratio of aldehyde/ketone to alcohols, catalyst dosage and reaction time on the yield of acetals and ketals were also studied. The results reveal that the H4SiW12O40/SiO2catalysis generally results in good yields of acetals and ketals under mild reaction conditions and the high activity and stability of the catalyst is well retained on recycling.


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