Catalyst For Hydration Of Nitriles Research Articles

Amorphous Fe0.7Cu0.3Ox as a Bifunctional Catalyst for Selective Hydration of Nitriles to Amides in Water

Amorphous Fe_0.7Cu_0.3O_<i>x</i> as a Bifunctional Catalyst for Selective Hydration of Nitriles to Amides in Water

Ag-embedded manganese oxide octahedral molecular sieve (Ag-OMS-2) nano-rods as efficient heterogeneous catalysts for hydration of nitriles to amides in aqueous solution.

Silver-embedded manganese oxide octahedral molecular sieve (Ag-OMS-2) nano-rods were synthesized using a pre-incorporation approach, and unambiguously characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). A highly uniform distribution of Ag nanoparticles embedded in the porous structure of OMS-2, was found to be in favor of high catalytic activity of the composite for hydration of nitriles to corresponding amides in aqueous solution. By using a catalyst dosage of 30 mg per mmol of substrate, in the temperature range of 80-100 °C, and reaction times of 4-9 h, excellent yields (73-96%) of the desired amides (13 examples) were obtained. Also, the catalyst was easy to recycle, and showed a slight decrease in efficiency after six consecutive runs.

Structures of nickel chloride and thiolate complexes supported by PCN and POCOP pincer ligands and catalytic reactivity of the chloride complexes.

Nickel chloride and thiolate complexes supported by benzene-pyridine-based nonsymmetrical PCN pincer ligands, [2-(tBu2PO)-6-(2-pyrindinyl-4-R)-C6H3]NiX (R = H, CH3, CF3; X = Cl, SH, SPh), were synthesized and fully characterized. The structures of these complexes and the catalytic reactivity of the chloride complexes were investigated along with the related POCOP counterparts [2,6-(tBu2PO)2C6H3]NiX (X = Cl, SH). It was found that the composition and substitution of the pincer backbone evidently influence the structures and catalytic reactivity. The Ni-P and Ni-Cipso bond lengths in the PCN complexes are significantly shorter than those in the POCOP complex. The Ni-Cl and Ni-S bond lengths in the PCN complexes are longer than those in the POCOP complexes. An electron rich pyrindinyl ring in the PCN complexes makes the Ni-Cl bond longer. The Ni-N bond length is more sensitive to the auxiliary ligand compared with the Ni-P bond length in the PCN complexes. The PCN chloride complexes were found to be active catalysts for selective hydration of nitriles to primary amides in the presence of NaOH at 80 °C and the catalytic activity increases with the increase of electron richness of the pyridinyl ring. However, the corresponding POCOP counterpart is inactive under the same conditions.

Silica supported spinel structured cobalt ferrite multifunctional nanocatalyst for hydration of nitriles and oxidative decarboxylation of phenylacetic acids

The silica‐supported cobalt ferrite spinel nanocatalyst has been successfully synthesized by the coprecipitation method and extensively characterized by FTIR, XRD, SEM‐EDX, TEM, BET, VSM, XPS, TGA, and ICP‐AES analysis. The bands observed at 3435 cm−1(νOHof Si‐OH) and 1637 cm−1(γOHof Si‐OH) in the FTIR spectrum of the as‐synthesized nanocatalyst unambiguously tell the presence of silica support. Moreover, a very weak intensity and a medium intensity peak at 683 cm−1and 463 cm−1suggested intrinsic stretching vibrations of Fe‐O and Co‐O of cobalt ferrite, respectively. The XRD pattern confirms the formation of CoFe2O4spinel. The average crystallite size was found to be 5.4 nm as calculated by using the Debye–Scherrer equation based on the (220) plane while the average particle size was found to be 5.08 nm from TEM analysis. The crystalline nature of the nanocomposite was confirmed by the SAED pattern. The successful incorporation of CoFe2O4on the surface of silica was established by the BET surface area measurements. The silica‐supported cobalt ferrite nanocatalyst has been explored as a heterogeneous multifunctional catalyst for hydration of nitriles and oxidative decarboxylation of phenylacetic acids as well under mild reaction conditions with moderate to excellent isolated yield of the desired products (60–99%). The catalyst was magnetically recoverable within a time frame of ~90 s and reusable up to the fifth catalytic cycle without profound loss of activity. A magnetic hysteresis study was performed to elucidate the magnetic behavior of the catalyst. The saturation magnetization value of 39.785 emu/g with a coercivity value of 110.87 Oe and saturation remanence value of 5.185 emu/g clearly indicated the presence of a ferromagnetic component in the material.

Activated Mont K10-Carbon supported Fe2O3: A versatile catalyst for hydration of nitriles to amides and reduction of nitro compounds to amines in aqueous media

Activated Mont K10-Carbon supported Fe2O3: A versatile catalyst for hydration of nitriles to amides and reduction of nitro compounds to amines in aqueous media

Arene-ruthenium(II)-phosphine complexes: Green catalysts for hydration of nitriles under mild conditions

Three new arene-ruthenium(II) complexes were prepared by treating [{RuCl(µ-Cl)(η6-arene)}2] (η6-arene = p-cymene) dimer with tri(2-furyl)phosphine (PFu3) and 1,3,5-triaza-7-phosphaadamantane (PTA), respectively to obtain [RuCl2(η6-arene)PFu3] [Ru]-1, [RuCl(η6-arene)(PFu3)(PTA)]BF4[Ru]-2 and [RuCl(η6-arene)(PFu3)2]BF4[Ru]-3. All the complexes were structurally identified using analytical and spectroscopic methods including single-crystal X-ray studies. The effectiveness of resulting complexes as potential homogeneous catalysts for selective hydration of different nitriles into corresponding amides in aqueous medium and air atmosphere was explored. There was a remarkable difference in catalytic activity of the catalysts depending on the nature and number of phosphorus-donor ligands and sites available for catalysis. Experimental studies performed using structural analogues of efficient catalyst concluded a structural-activity relationship for the higher catalytic activity of [Ru]-1, being able to convert huge variety of aromatic, heteroaromatic and aliphatic nitriles. The use of eco-friendly water as a solvent, open atmosphere and avoidance of any organic solvent during the catalytic reactions prove the reported process to be truly green and sustainable.

Nanorod Manganese Oxide as an Efficient Heterogeneous Catalyst for Hydration of Nitriles into Amides

Hydration of nitriles has been practically used for the production of amides, wherein the homogeneous catalysts including acids/bases and metal complexes are generally employed. Here, we report tha...

A Heterogeneous Ruthenium dmso Complex Supported onto Silica Particles as a Recyclable Catalyst for the Efficient Hydration of Nitriles in Aqueous Medium.

In the present work, we describe an efficient method for the covalent anchoring of a Ru-dmso complex onto two types of supports: mesoporous silica particles (SP) and silica coated magnetic particles (MSNP). First, we have prepared and characterized the molecular complexes containing the bidentate pyridylpyrazole ligands pypz-Me and pypz-CH2COOEt, with the formula [RuIICl2(pypz-R)(dmso)2] (R = Me, 1; CH2COOEt, 2). Complex 2 was anchored onto the silica supports, yielding the heterogeneous systems SP@2 and MSNP@2 which were fully characterized by IR, UV-vis, SEM, TEM, TGA, and XPS techniques. Hydration of representative nitriles has been tested with the molecular complexes and their SP@2 and MSNP@2 heterogeneous counterparts, in aqueous medium under neutral conditions. The heterogeneous catalysts display high yields and excellent selectivity values. Both systems can be reused throughout several cycles for benzonitrile and acrylonitrile substrates, without any significant loss in reactivity. The MSNP@2 material can be easily recovered by a magnet, facilitating its reusability.

Ru (III) Schiff‐base complex anchored on nanosilica as an efficient and retrievable catalyst for hydration of nitriles

Transition metal catalyzed hydration of nitriles is an attractive methodology for amide synthesis, and hence recently attracted wide attention. It is one of the significant organic transformations as amides play a vital role in biological, pharmaceutical and industrial applications. In this work, we report the synthesis of a new solid supported Ru (III) Schiff base complex, Ru@imine‐nanoSiO2immobilized on nanosilica obtained from rice husk. The complex was characterized by FTIR, powder X‐ray diffraction, BET surface area measurement, UV–vis, SEM–EDX, TEM, ESR, X‐ray photoelectron spectroscopy and ICP‐AES analysis. Using Ru@imine‐nanoSiO2as the catalyst, the hydration of nitriles ini‐PrOH at 40 °C was studied which resulted in good isolated yields (60–99%). The catalyst can be recycled and reused up to 5thcycle without any loss in activity. The products were characterized by FTIR, GC–MS and1H‐NMR spectroscopy and compared with authentic samples.

Bifunctional organometallic catalysts for selective hydration of nitriles to amides

Bifunctional organometallic catalysts for selective hydration of nitriles to amides

Ru(ii)-dmso complexes containing azole-based ligands: synthesis, linkage isomerism and catalytic behaviour.

The reaction of cis,fac-[RuCl2(dmso-S)3(dmso-O)], 1, with different azole (L) ligands leads to new [RuCl2(L)(dmso-S)3] compounds (L = CH3-pz-H, 2; NO2-pz-H, 3; CF3-pz-H, 4 and Br-Hind, 5). Complexes 2-5 have been characterized by analytical, spectroscopic and electrochemical techniques as well as by monocrystal X-ray diffraction analysis. Upon oxidation to Ru(iii) the complexes undergo linkage isomerization of a S-bound dmso ligand and the corresponding kinetic rates as well as the thermodynamic properties have been determined for compound 2 and also for the previously described [Ru(II)Cl2(pypz-H)(dmso-S)2] (pypz-H = 2-(3-pyrazolyl)pyridine), 6, from cyclic voltammetries performed at different scan rates. The exposure of compound 2 to visible light in acetonitrile produces the substitution of one dmso ligand by a solvent molecule generating a new compound, 2'. The irradiation of solutions of compounds 2 and 6 in chloroform leads in both cases to the substitution of one dmso by a chlorido ligand in parallel to the oxidation of Ru(ii) to Ru(iii) generating complexes 2'' and 6' respectively. The reactivity of compounds 2-6 has been tested with regard to the hydration of nitriles in water as a solvent, displaying in all cases good performance and selectivity for the corresponding amides.

Poly(amic acid) salt-stabilized silver nanoparticles as efficient and recyclable quasi-homogeneous catalysts for the aqueous hydration of nitriles to amides

The reversible pH-response of the Ag–PAAS catalyst allows it to catalyze the selective hydration of various nitriles quasi-homogeneously in water and to be easily recovered by simply adjusting the pH value of the solution.

Ruthenium(II) complexes incorporating salicylaldiminato-functionalized N-heterocyclic carbene ligands as efficient and versatile catalysts for hydration of organonitriles

We describe a new synthetic procedure for synthesis of ruthenium(II) complexes containing salicylaldiminato functionalized mixed N-heterocyclic carbene (NHC) ligand and phosphine co-ligand. The complexes (3a–3d) have been obtained in good to excellent yields by transmetalation from the corresponding Ag–NHC complexes (2a–2d) as carbene transfer reagents. All the [Ru–NHC] complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. The ligands 1a–1d show their versatility by switching to be O,N,C-chelating in these ruthenium(II) complexes. The resulting complexes have been evaluated as potential catalysts for the selective hydration of nitriles to primary amides, and related amide bond forming reactions, in environmentally friendly medium. The reaction tolerated ether, hydroxyl, nitro, bromo, formyl, pyridyl, benzyl and alkyl functional groups. The catalyst was stable for weeks and could be recovered and reused more than six times without significant loss of activity.

Metal-centered oxidation decreases nitrile hydration activity of bioinspired (N2S3)Ru-PPh3 precatalysts

A series of ruthenium(II) nitrile hydration catalysts based on the pentadentate ligand 4,7-bis(2′-methyl-2′-mercaptopropyl)-1-thia-4,7-diazacyclononane and its sulfur-oxidized derivatives has been oxidized at the metal center yielding their ruthenium(III) counterparts. Metal-centered oxidation results in complete loss of nitrile hydration activity for the dithiolato (RS−/RS−) parent complex. The sulfur-oxidized thiolato/sulfinato (RS−,RSO2−) derivative displays a decrease in turnover number from 238±23 to 3±1 upon oxidation of Ru(II) to Ru(III). A similar decrease in turnover number from 242±23 to 7±3 is observed upon metal-centered oxidation of the sulfenato/sulfinato (RSO−, RSO2−) derivative. The inactive complex [(4,7-bis(2′-methyl-2′-mercaptopropyl)-1-thia-4,7-diazacyclononane)(triphenyl-phosphine)ruthenium(III)]hexafluorophosphate has been synthesized and characterized by electronic spectroscopy, electron paramagnetic resonance, and single crystal X-ray diffraction studies.

ChemInform Abstract: Metal‐Catalyzed Nitrile Hydration Reactions: The Specific Contribution of Ruthenium

AbstractReview: 160 refs.

ChemInform Abstract: An Efficient Ruthenium(IV) Catalyst for the Selective Hydration of Nitriles to Amides in Water under Mild Conditions.

A Ru(IV) catalyst able to promote the selective hydration of nitriles to amides in water, at low metal loadings and under mild conditions, is presented.

Investigation of binap-based hydroxyphosphine arene–ruthenium(ii) complexes as catalysts for nitrile hydration

The binap-based hydroxyphosphine-(η6-arene)–ruthenium(II) complexes [RuX{η6:κ1(P)-PPh2-binaphthyl}{PPh2(OH)}][OTf] (X = OTf (4), Cl (5)) have been evaluated as potential catalysts for the selective hydration of nitriles to primary amides. The triflate derivative 4 proved to be the most active, being able to hydrate a large variety of aromatic, heteroaromatic, α,β-unsaturated and aliphatic nitriles in pure water at 100 °C. The utility of complex 4 to promote the catalytic rearrangement of aldoximes has also been demonstrated. In addition, insights about the role played by the hydroxyphosphine ligand PPh2(OH) during the catalytic reactions are given.

ChemInform Abstract: Amberlyst A26 OH as a Recyclable Catalyst for Hydration of Nitriles and Water‐Based Synthesis of 4(1H)‐Quinazolinones from 2‐Aminobenzonitrile and Carbonyl Compounds.

Selective hydration of nitriles to primary amides as well the base-catalyzed synthesis of 2-substituted 4(1H)-quinazolinones via reaction of 2-aminobenzonitrile with carbonyl compounds using macroporous Amberlyst A26 OH in H2O–EtOH is described. The latter reaction proceeds via tandem hydration of 2-aminobenzonitrile, condensation of the in situ generated 2-aminobenzamide with carbonyl compounds, and cyclization of the imine intermediate to give the quinazolinone derivatives.

An efficient ruthenium(IV) catalyst for the selective hydration of nitriles to amides in water under mild conditions.

A Ru(IV) catalyst able to promote the selective hydration of nitriles to amides in water, at low metal loadings and under mild conditions, is presented.

Amberlyst A26 OH as a Recyclable Catalyst for Hydration of Nitriles and ­Water-Based Synthesis of 4(1H)-Quinazolinones from 2-Aminobenzonitrile and Carbonyl Compounds

Selective hydration of nitriles to primary amides as well the base-catalyzed synthesis of 2-substituted 4(1H)-quinazolinones via reaction of 2-aminobenzonitrile with carbonyl compounds using macroporous Amberlyst A26 OH in H2O–EtOH is described. The latter reaction proceeds via tandem hydration of 2-aminobenzonitrile, condensation of the in situ generated 2-aminobenzamide with carbonyl compounds, and cyclization of the imine intermediate to give the quinazolinone derivatives.