Hydrolysis Of Acetonitrile Research Articles

The reaction behaviors of acetonitrile and ethyl acetate simultaneous degradation over Cu–Ce/ZSM–5 catalyst

Aiming at the coexistence of pollutants in the actual industrial process, the catalytic oxidation of acetonitrile and ethyl acetate mixture on the Cu–Ce/ZSM–5 catalyst was studied. The mutual inhibition effect during catalytic removal of acetonitrile and ethyl acetate mixture was observed. Acetonitrile showed a more obvious inhibitory effect on the conversion of ethyl acetate, and the introduction of ethyl acetate reduced the N2 selectivity of acetonitrile oxidation. The simulation results demonstrated acetonitrile could be preferentially adsorbed on Cu center of the catalyst surface, leading to significant inhibition of the initial conversion of ethyl acetate. In addition, the coexistence of ethyl acetate would weaken the hydrolysis of acetonitrile to generate carboxylic acid and –NHx species. As such, no enough adsorbed NHx species could be used to reduce the NOx produced by excessive oxidation of acetonitrile, resulting in a decreased in N2 selectivity. This study could provide reference on the application of catalysts for cyanide–containing waste gas degradation.

First cadmium coordination compound as an efficient flocculant for Congo red

• New Cd(II) coordination compound of 2-phenylimidazo[4,5- f ][1,10]phenanthroline was synthesized via hydrolysis of acetonitrile to acetate. • This compound proves to be the first coordination compound for rapid, specific and complete flocculation of Congo red. • The flocculation mechanism is rationally proposed based on various methods. A cadmium coordination compound, [Cd(pip) 2 (OAc) 2 ]·H 2 O (pip is 2-phenylimidazo[4,5- f ][1,10]phenanthroline), has been successfully synthesized hydrothermally through an in situ hydrolysis of acetonitrile to acetate, and structurally characterized. This compound was found to be able to flocculate Congo red (CR) rapidly and almost quantitatively at pH 7 with low dosage, representing the first coordination compound of such capability. Based on various criteria including infrared spectra, thin layer chromatography and zeta potential analysis, the flocculation mechanism has been proposed to involve displacement of acetate in the complex by CR anion and successive hydrogen bonding and bridging effect, different from the mechanism for traditional polyelectrolyte flocculants.

Intrinsic acetamide brush-off by polyurea biodendrimers.

The presence of genotoxic impurities in active pharmaceutical ingredients (APIs) is a major concern for the pharmaceutical industry. Acetamide is a common genotoxic byproduct found in synthetic routes of many APIs, mainly due to acetonitrile hydrolysis, and selective scavenging is a still a challenging task. Herein, as a proof-of-concept, we evaluate polyurea (PURE) biodendrimers as strategic nanopolymers to prepare safe drug nanoformulations from mixtures containing acetamide, using (S)-ibuprofen (IBF) as a model drug. Furthermore, computational molecular dynamics (MD) simulations were conducted to rationalize in vitro results and to identify the key intermolecular interactions within mixtures. Experimental data were corroborated by MD simulations which showed that acetamide, IBF and carboxyfluorescein interactions with PURE biodendrimers are mostly at the surface. Also, PURE nanoformulations appear to be driven by hydrogen bonding, electrostatic and hydrophobic interactions.

New Photochromic Salt Spiropyran with Benzyl Substituent

A new salt spiropyran of indoline series containing benzyl substituent in the 8'-position of the [2H]-chromene moiety of the molecule has been synthesized and studied. The structure of the obtained compound has been confirmed by methods 1H NMR and IR spectroscopy. The study of spectral characteristics and photochromic behavior of the target compound has shown that growing of its single crystal resulted in destruction on account of hydrolysis in acetonitrile. The 1H NMR spectra of the initial salt spiropyran and product of hydrolysis have been compared.

Exploring the Performance Improvement of Magnetocaloric Effect Based Gd-Exclusive Cluster Gd60.

Despite wide potential applications of Gd-clusters in magnetocaloric effect (MCE) owing to f7 electron configuration of Gd(III), the structural improvement in order to enhance MCE remains difficult. A new approach of the situ hydrolysis of acetonitrile is reported, and the slow release of small ligand CH3COO- is realized in the design and synthesis of high-nuclearity lanthanide clusters. A large lanthanide-exclusive cluster complex, [Gd60(CO3)8(CH3COO)12(μ2-OH)24(μ3-OH)96(H2O)56](NO3)15Br12(dmp)5·30CH3OH·20Hdmp (1-Gd60), was isolated under solvothermal conditions. To the best our knowledge, cluster 1 possesses the high metal/ligand ratio (magnetic density) and the largest magnetic entropy change (- Δ Smmax = 48.0 J kg-1 K-1 at 2 K for Δ H = 7 T) among previously reported high-nuclearity lanthanide clusters.

Counterion-Controlled Formation of an Octanuclear Uranyl Cage with cis-1,2-Cyclohexanedicarboxylate Ligands.

cis-1,2-Cyclohexanedicarboxylic acid ( c-chdcH2) was reacted with uranyl nitrate under (solvo-)hydrothermal conditions in the presence of different possible counterions. Two neutral complexes of 1:1 stoichiometry were obtained, [UO2( c-chdc)(DMF)] (1) and [UO2( c-chdc)(H2O)] (2), which crystallize as two-dimensional coordination polymers and do not include the additional cations present in solution. In contrast, the complex [NH4][PPh4][(UO2)8( c-chdc)9(H2O)6]·3H2O (3) crystallized in the presence of PPh4Br, ammonium cations being generated in situ from acetonitrile hydrolysis. This complex of 8:9 uranium:ligand stoichiometry contains an octanuclear anionic cage of D3 symmetry with a pseudo-cubic arrangement of uranium atoms. The ammonium cation is held within the cage through four hydrogen bonds with uranyl oxo groups directed inward. This cage complex is luminescent, although with a low quantum yield of 0.06, indicating limited potential as a photo-oxidant of included species.

Rapid naked-eye luminescence detection of carbonate ion through acetonitrile hydrolysis induced europium complexes

[Eu2(Hhpip)2(OAc)6] in DMSO shows a specific and prompt photoluminescence colour change in response to CO32−detectable with naked eyes.

Synthesis and Characterization of an Open and a Cyclic Polyaza Complexes of Copper(II) Having Caged Moiety; Cyclization Through Copper(II) Enhanced Hydrolysis from Nitrile to Amide

The preparation, X‐ray structure and properties of noncyclic (1) and cyclic (2) polyaza copper(II) complexes with caged moiety, and copper(II) enhanced hydrolysis of acetonitrile participated in the cyclization of 1 to 2 are reported. The average Cu‐N distances of complex 1 and 2 are somewhat shorter than those of square‐planar or square‐pyramidal complexes of analogue [14]‐membered ring copper(II) complexes. These results derived from the squeeze effect of caged moiety of bicyclononan. Reaction of formaldehyde and complex 1 in the presence of base in acetonitrile solution produced complex 2. In this catalytic route, coordination of acetonitrile onto Cu(II) ion, a Lewis acid, of complex 1 makes the electrophilicity of the carbon of nitrile increased. Absorption maximum of the complex 2 is shifted to somewhat shorter wavelength than that of the complex 1. It is supposed to the higher ligand field stabilization energy of complex 2, which has cyclized ligand, comparing that of the complex 1, which has open ligand. These complexes are stable against disproportionation in copper(I) state.

Potential Safety Hazards Associated with Using Acetonitrile and a Strong Aqueous Base

Acetonitrile, a common solvent in organic synthesis, can be hydrolyzed in the presence of a strong aqueous base, such as NaOH or KOH, which can propagate into a runaway reaction. For a process recently reviewed in our laboratory, a possible loss of cooling incident during the desired reaction was found to have the potential to self-heat to the onset temperature of this hydrolysis reaction. This base-catalyzed acetonitrile hydrolysis was determined to potentially escalate into a runaway reaction, where it could lead to secondary exothermic runaway reactions of the reaction mixture. The use of acetonitrile was preferred for the initial cyclization step. Thus, adequate removal of acetonitrile prior to the following step avoided the process safety hazard posed by the hydrolysis of the acetonitrile solvent. The findings presented in this work serve as an alert to chemists and engineers for the potential safety hazards when scaling up a process in which the solvent becomes a reactant.

Tuning the structure and Zn(ii) sensing of lanthanide complexes with two phenylimidazophenanthrolines by acetonitrile hydrolysis

1D/0D lanthanide complexes of phenylimidazophenanthrolines were constructedviahydrolysis of acetonitrile, and0-Eushows prompt photoemission response to Zn2+.

Influence of the Acetamide from Acetonitrile Hydrolysis in Acid-Contained Mobile Phase on the Ultraviolet Detection in High Performance Liquid Chromatography

The paper presents the influence of acetamide on ultraviolet detection after generation of acetonitrile by hydrolysis in the presence of trifluoroacetic acid in the HPLC mobile phase. The acetonitrile, with added varying contents of trifluoroacetic acid and water, was determined by GC–MS at various times. The results showed that the concentration of acetamide increased approximately linearly with time. Using a mixed standard sample solution and a model mobile phase of acetonitrile-water-tri-fluoroacetic acid (25:75:0.3, v/v) after 0, 24 and 48 h, the influence of the hydrolyzate acetamide on HPLC detection was investigated at the wavelength of 205–220 nm. The results showed that the limit of detection (LOD) of standard sample lost about 30 % after the mobile phase was placed 48 h. It is suggested that the acid-containing mobile phase was placed no more than 24 h for HPLC trace analysis at the wavelength of 205–220 nm.

Effects of co-feeding with nitrogen-containing compounds on the performance of supported cobalt and iron catalysts in Fischer–Tropsch synthesis

The performance of supported cobalt and iron catalysts in low and high temperature Fischer–Tropsch synthesis was investigated in the presence of small amounts of ammonia in syngas. Ammonia was co-fed to the reactor either by in-situ hydrolysis of acetonitrile or by addition of aqueous ammonia.The addition of acetonitrile and ammonia resulted in significant irreversible deactivation of alumina supported cobalt catalysts. Lower methane and higher C5+ hydrocarbon selectivities were observed. Iron based catalysts did not show any noticeable deactivation in the presence of acetonitrile or ammonia. Moreover, Fischer–Tropsch reaction rate slightly increased after addition of the nitrogen-containing compounds to silica and alumina supported samples. Lower methane selectivity and higher C2–C4 olefin to paraffin ratio were observed in the presence of ammonia when the catalysts were reduced in hydrogen. Iron catalysts activated in carbon monoxide did not demonstrate any significant effect of ammonia on the selectivity. The catalytic data were explained by irreversible formation of inactive cobalt nitrides in cobalt catalysts and transformation of metallic iron and iron oxides in the presence of acetonitrile and ammonia into iron nitrides and iron carbides active in Fischer–Tropsch synthesis.

Spectroscopic Analyses on Reaction Intermediates Formed during Chlorination of Alkanes with NaOCl Catalyzed by a Nickel Complex

The spectroscopic, electrochemical, and crystallographic characterization of [((Me,H)PyTACN)Ni(II)(CH3CN)2](OTf)2 (1) ((Me,H)PyTACN = 1-(2-pyridylmethyl)-4,7-dimethyl-1,4,7-triazacyclononane, OTf = CF3SO3) is described together with its reactivity with NaOCl. 1 catalyzes the chlorination of alkanes with NaOCl, producing only a trace amount of oxygenated byproducts. The reaction was monitored spectroscopically and by high resolution electrospray-mass spectrometry (ESI-MS) with the aim to elucidate mechanistic aspects. NaOCl reacts with 1 in acetonitrile to form the transient species [(L)Ni(II)-OCl(S)](+) (A) (L = (Me,H)PyTACN, S = solvent), which was identified by ESI-MS. UV/vis absorption, electron paramagnetic resonance, and resonance Raman spectroscopy indicate that intermediate A decays to the complex [(L)Ni(III)-OH(S)](2+) (B) presumably through homolytic cleavage of the O-Cl bond, which liberates a Cl(•) atom. Hydrolysis of acetonitrile to acetic acid under the applied conditions results in the formation of [(L)Ni(III)-OOCCH3(S)](2+) (C), which undergoes subsequent reduction to [(L)Ni(II)-OOCCH3(S)](2+) (D), presumably via reaction with OCl(-) or ClO2(-). Subsequent addition of NaOCl to [(L)Ni(II)-OOCCH3(S)](+) (D) regenerates [(L)Ni(III)-OH(S)](2+) (B) to a much greater extent and at a faster rate. Addition of acids such as acetic and triflic acid enhances the rate and extent of formation of [(L)Ni(III)-OH(S)](2+) (B) from 1, suggesting that O-Cl homolytic cleavage is accelerated by protonation. Overall, these reactions generate Cl(•) atoms and ClO2 in a catalytic cycle where the nickel center alternates between Ni(II) and Ni(III). Chlorine atoms in turn react with the C-H bonds of alkanes, forming alkyl radicals that are trapped by Cl(•) to form alkyl chlorides.

Discrete and Polymeric Cu(II) Coordination Complexes with a Flexible bis-(pyridylpyrazole) Ligand: Structural Diversity and Unexpected Solvothermal Reactivity

Reported here is the synthesis and structural characterisation of five copper complexes derived from the bis-bidentate ligand 4,4′-methylenebis(1-(2-pyridyl)-3,5-dimethylpyrazole), L. Complex 1, [Cu2L(CH3COO)4(OH2)2]·6H2O, is a single stranded unsaturated helical species that forms a highly connected three-dimensional hydrogen-bonding network, whereas [Cu2L(NO3)4], 2, is a coordination polymer derived from [Cu2L] fragments linked together via bridging nitrate anions to yield undulating two-dimensional sheets with (6,3)-topology. Complexes 3, 4, and 5 co-crystallise within a single batch when L is reacted under solvothermal conditions with Cu(NO3)2·2.5H2O in acetonitrile, and each contains a co-ligand formed by either decomposition of the solvent or ligand. Complex 3, [Cu4(NO3)4(µ-CH3COO)2(µ-OH)2L2], forms an unusual discrete cyclic tetrameric species containing acetate co-ligands derived through acetonitrile hydrolysis; whereas complex 4, [CuL(C2O4)(NO3)], forms a one-dimensional coordination polymer containing bridging oxalate co-ligands, formed through hydrolysis and oxidation of acetonitrile. Complex 5, [Cu2L(µ-CN)2], is a two-dimensional coordination polymer with (6,3) topology where bridging between Cu(i) centres is furnished by cyanide co-ligands, suggesting a ligand decomposition pathway for its origin, and produced with concomitant reduction of the Cu(ii) starting reagent. Having initially obtained 3, 4, and 5 serendipitously each were then prepared as pure phases by careful adjustment and control of the reaction conditions (reactant stoichiometry, concentrations, and solvothermal temperature), details of which are discussed.

Facile Solvothermal Method for Fabricating Arrays of Vertically Oriented α-Fe2O3 Nanowires and Their Application in Photoelectrochemical Water Oxidation

The controlled growth of highly ordered, [211]-oriented FeOOH nanowire arrays on various substrates, such as Pt, W, Ti, and fluoride-doped tin oxide (FTO) glass, was achieved by a solvothermal method in aqueous acetonitrile solutions at 80-120 degrees C, following by annealing to form alpha-Fe2O3 nanowires with their [110] direction perpendicular to the substrate. Adjusting the reaction pH and temperature enables control of the nanowire length. In particular, the pH has a dramatic effect on the nanowire growth, with low pH resulting in the growth of longer wires because of the acid-catalyzed hydrolysis of acetonitrile. Photoactive hematite was prepared by diffusing Ti or Sn into the nanowires during thermal annealing. Processing parameters that influenced the photoelectrochemical performance of these nanowire arrays, including the annealing regime, temperature, and length of nanowires, are discussed in detail. The Ti- and Sn-doped one-dimensional [110)-oriented alpha-Fe2O3 nanowire arrays provide an effective pathway for electron transport, demonstrating increased photocurrents, up to 1.3 mA/cm(2) under air mass 1.5 global (AM 1.5G) illumination, in photoelectrochemical water oxidation.

Controlled Sulfur Oxygenation of the Ruthenium Dithiolate (4,7-Bis-(2′-methyl-2′-mercaptopropyl)-1-thia-4,7-diazacyclononane)RuPPh3 under Limiting O2 Conditions Yields Thiolato/Sulfinato, Sulfenato/Sulfinato, and Bis-Sulfinato Derivatives

The ruthenium(II) dithiolate complex (bmmp-TASN)RuPPh(3) (1) reacts with O(2) under limiting conditions to yield isolable sulfur oxygenated derivatives as a function of reaction time. With this approach, a family of sulfur-oxygenates has been prepared and isolated without the need for O-atom transfer agents or column chromatography. Addition of 5 equiv of O(2) to 1 yields the thiolato/sulfinato complex (bmmp-O(2)-TASN)RuPPh(3) (2) in 70% yield within 5 min. Increasing the reaction time to 12 h yields the sulfenato/sulfinato derivative (bmmp-O(3)-TASN)RuPPh(3) (3) in 82% yield. Longer reaction times and/or additional O(2) exposure yield the bis-sulfinato complex (bmmp-O(4)-TASN)RuPPh(3) (4). All products remain in the Ru(II) oxidation state under the conditions employed. Stoichiometric hydrolysis of acetonitrile to acetamide by 2 and 3 is observed in mixed acetonitrile, methanol, PIPES buffer (pH = 7.0) mixtures. The Ru(III)/(II) reduction potential of -0.85 V (versus ferrocenium/ferrocene) for 1 shifts to -0.39 and -0.26 V for 2 and 3, respectively, because of the decreased donor ability of sulfur upon oxygenation. X-ray diffraction studies reveal a decrease in Ru-S bond distances upon oxygenation by 0.045(1) and 0.158(1) Å for the sulfenato and sulfinato donors, respectively. Conversely, sulfur-oxygenation increases the Ru-P bond distance by 0.061(1) Å from 1 to 2 and an additional 0.027(1) Å from 2 to 3. Density functional theory investigations using the BP86 and B3LYP functionals with a LANL2DZ basis set for Ru and the 6-31G(d) basis set for all other atoms reveal a direct correlation between the oxygenation level and the Ru-P distance with an increase of 0.031 Å per O-atom.

Mechanism of TBD-catalyzed hydrolysis of acetonitrile

1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) has recently been shown to be an effective organocatalyst for the hydrolysis reaction of acetonitrile. This reaction involves the acetamide-forming reaction of acetonitrile hydrolysis and the further hydrolysis of acetamide to form acetic acid and NH 3. Density functional theory (DFT) and Hartree–Fock (HF) methods were employed to comprehensively investigate these two hydrolysis steps to elucidate the TBD-catalyzation mechanism. Structures and energies of the reactants, intermediates, transition states and products along the reaction path were presented. Charge population and bond orders were given by natural bond orbital (NBO) analysis to clarify the computed atomic and molecular behaviors. The results showed that compared with the noncatalyzed reaction, the TBD-catalyzed process had significantly lower energy barriers in both the hydration steps and the isomerization steps. As a result, the whole reaction process could be accelerated and the TBD-catalyzation mechanism was clarified.

Synthesis and Structure of Novel RuII - N≡C - Me Complexes and their Activity Towards Nitrile Hydrolysis: An Examination of Ligand Effects

The synthesis and isolation of new RuII–acetonitrile complexes, of general formula trans,fac-[Ru(bpea)(B)(MeCN)](BF4)2 (bpea = N,N-bis(2-pyridylmethyl)ethylamine; B = bpy, 2,2′-bipyridine, 4; B = dppe, 1,2-bis(diphenylphosphino)ethane, 5), together with a synthetic intermediate trans,fac-[Ru(NO3)(bpea)(dppe)](BF4), 6, are described. Ru(bpea)Cl3, 1, is used as the starting material for the synthesis of all complexes 2–6 presented in this paper, which are characterized by analytical, spectroscopic (IR, UV/Vis, 1D and 2D NMR), and electrochemical techniques (cyclic voltammetry). Furthermore, complexes 4, 5, and 6 have also been characterized in the solid state by single crystal X-ray diffraction analysis. Their structures show a distorted octahedral geometry where the bpea ligand binds in a facial mode, the bidentate ligands bpy and dppe bind in a chelate manner, and finally the MeCN or the NO3 – ligand occupy the sixth position of the octahedral Ru metal centre. The kinetics of the basic hydrolysis of the coordinated MeCN ligand for complexes 4 and 5 and for the related complex [Ru(phen)(MeCN)([9]aneS3)](BF4)2, 7, which contains the 1,4,7-trithiacyclonane ligand ([9]aneS3) and 1,10-phenanthroline (phen) is also described. Second-order rate constants for acetonitrile hydrolysis measured at 25°C of k = 1.01 × 10–3 M–1 s–1 for 4, 1.08 × 10–4 M–1 s–1 for 5, and 6.8 × 10–3 M–1 s–1 for 7, have been obtained through UV-vis spectroscopy. Activation parameters have also been determined over the temperature range 25.0–45.0°C and agree with a mechanism that involves an associative rate-determining step. Finally the electronic and steric influence of the auxiliary ligands on this reaction for the above and related complexes is discussed.

Cutinase activity in supercritical and organic media: water activity, solvation and acid–base effects

We performed a comparative study on the activity of Fusarium solani pisi cutinase immobilized on zeolites NaA and NaY, in n-hexane, acetonitrile, supercritical ethane (sc-ethane) and sc-CO 2, at two different water activity ( a W) values set by salt hydrate pairs in situ and at acid–base conditions fixed with solid-state buffers of aqueous p K a between 4.3 and 10.6. The reaction studied was the transesterification of vinyl butyrate by ( R,S)-2-phenyl-1-propanol. The transesterification activity of cutinase was highest and similar in sc-ethane and in n-hexane, about one order of magnitude lower in acetonitrile and even lower in sc-CO 2. Activity coefficients ( γ) generated for the two substrates indicated that they were better solvated in acetonitrile and thus less available for binding at the active site than in the other three solvents. γ data also suggested higher reaction rates in sc-ethane than in n-hexane, as observed, and provided evidence for a direct negative effect of sc-CO 2 on enzyme activity. Manipulation of the acid–base conditions of the media did not afford any improvement of the initial rates of transesterification relative to the blanks (no added acid–base buffer, only salt hydrate pair), except in the case of cutinase immobilized on zeolite NaA in sc-ethane at a W = 0.7. The poor performance of the blank in this case and the great improvement observed in the presence of a basic buffer suggest a deleterious acidic effect in the medium which, an experiment without additives confirmed, was not due to the known acidic character of the salt hydrate pair used to set a W = 0.7. In acetonitrile, increasing a W was accompanied by a decrease in initial rates of transesterification, unlike in the other solvents. There was considerable hydrolysis in acetonitrile, where initial rates of hydrolysis increased about 20-fold from a W = 0.2 to 0.7. Hydrolysis was less pronounced in sc-ethane and in n-hexane, and only at a W = 0.7, and in sc-CO 2 butyric acid was detected only at very long reaction times, in agreement with a generally low catalytic activity. Cutinase enantio-selectivity towards the alcohol substrate was low and unaffected by any manipulation of medium conditions.

On-line monitoring of the hydrolysis of acetonitrile in near-critical water using Raman spectroscopy

The hydrolysis of CH 3CN in near-critical water, without added catalyst, has been successfully monitored with on line Raman spectroscopy, up to 350 °C at 300 bar. Using a unique miniature high pressure and high temperature (HTHP) spectroscopic cell, in situ quantitative measurements with Raman spectroscopy have allowed the pseudo-first-order rate constant and the activation energy for the reaction to be calculated. The effects of temperature, pressure, density, dielectric constant, ionic product of water and initial CH 3CN concentration on the reaction rate have also been investigated. The reaction involves the formation of CH 3CONH 2 as an intermediate, and gives CH 3COOH as the final product. No other products have been detected in the effluent. Water plays the role of solvent, reactant and acid catalyst at the same time, whereas the reaction also shows an autocatalytic effect, due to CH 3COOH which accumulates in the system as the reaction progresses.