Acrylonitrile In Presence Research Articles

Photoinduced Tandem C−O Bond Reduction/Ketyl Radical Addition Reactions of α‐Keto‐N,O‐Acetals Enabled by Proton‐Coupled Electron Transfer

AbstractThe C10a‐acetoxylated tetrahydroazepino[1,2‐a]indole‐6,11‐diones are a class of tricyclic oxindoles that feature an α‐keto‐N,O‐acetal substructure, rendering them highly susceptible to SET reduction followed by fragmentation. In protic medium, they undergo a PCET‐assisted two‐step reduction including an interposed C−O bond cleavage that can be initiated photocatalytically as well as by cathodic reduction, and which generates nucleophilic ketyl radicals. In the presence of acrylonitrile and DIPEA as additional reactants, the photoinduced reaction unfolds as a tandem C−O bond reduction/ketyl radical conjugate addition, to furnish C10a‐reduced, C11‐cyanoethyl‐substituted tricyclic azepino‐[1,2‐a]indole derivatives with high stereoselectivity.

Acrylonitrile-Structured Ternary Co-oligomers of 4-Isopropenylphenol, Phenol, and Formaldehyde as Sorbents for Recovery of Uranyl Ions from Aqueous Systems

Triple co-oligomers of 4-isopropenylphenol, phenol and formaldehyde were synthesized and used for the first time as precursors in the structuring reaction in the presence of acrylonitrile and the initiator benzoyl peroxide. The yield of cross-linked copolymers is 84% (of theory). The use of hydrolyzed cross-linked copolymers is shown to be effective as sorbents for the extraction of UO22+ ions from model aqueous systems under batch conditions, and the degree of their sorption significantly depends on the medium pH, the initial concentration of UO22+ ions and the exposure time. The best results were achieved at pH 7 and 9, at which the degree of extraction of UO22+ ions from an aqueous solution with their initial concentration of 134 ± 0.5 mg L–1 is ~93.5% (room temperature, 24 h), while the sorption capacity of the cross-linked copolymer is ~210 mg g–1. The highest sorption capacity of the copolymer reaches 300 ± 30 mg g–1. The possibility of regeneration of the sorbent with mineral acid (НNO3, HCl) was revealed; the maximum degree of desorption of UO22+ ions is ~91%.

Novel bio-degradation shortcut for the treatment of acrylonitrile-containing wastewater using column bio-oxidation with Sulfurovum bacteria in activated sludge

Currently, there is a paucity of research focused on the column bio-oxidation of organic wastewater containing acrylonitrile. Consequently, it is imperative and meaningful to investigate the application of column bio-oxidation for the treatment of this specific type of wastewater. To initiate the study, microorganisms were enriched from activated sludge obtained from a chemical plant. These microorganisms were subsequently acclimated by introducing essential nutrients and optimizing reaction conditions such as the liquid-to-solid ratio, oxygen concentration, pH, and temperature. The resulting microbial consortium was then evaluated for its capacity to degrade acrylonitrile. The results show that at the solid to liquid ratio 3:40 (g/L), anaerobic environment (O2<5%), pH 7.5, 30 °C, nutrients (glucose 5 g, MgSO4·7H2O 0.5 g, KH2PO4 1.0 g, KNO3 1.0 g) and hydraulic retention time 96 h. The average removal rate of acrylonitrile can reach 86.95 %. The evolution of the microbial community was characterized by 16S rRNA gene analysis. It revealed that Sulfurovum gradually replaced other microorganisms as the dominant species over time in the response. In conjunction with the monitoring of elemental nitrogen during the reaction, it was found that Sulfurovum showed a two-step pathway in the process. In the first stage, Sulfurovum converted acrylonitrile as the nitrogen source to R-COOH and produced NH3/NH4- in the presence of acrylonitrile. In the second stage, Sulfurovum used exceed NO3- as the nitrogen source, enabled the nitrogen cycle to proceed.

Free volume expansion in some polybutadiene–acrylonitrile rubbers: comparison between theory and experiments

The free volume dependence on temperature has been investigated in three butadiene-acrylonitrile copolymers and in a butadiene-acrylonitrile-isoprene terpolymer, above the glass transition in order to apply the lattice-hole model. Macroscopic behavior was highlighted by dilatometry; positron annihilation lifetime spectroscopy (PALS) was used to shed light on the free volume microstructure. Coupling of the two techniques allowed us to obtain the number density of holes under specific geometrical assumptions about the cavities. Comparison with the theoretical free volume fraction suggests hole shapes more similar to discs than to spheres, but with aspect ratio decreasing at increasing temperature. Such preferential growth in the radial direction is not influenced by the presence of acrylonitrile, contrarily to what recently found in butadiene-isoprene blends, where the increasing amount of isoprene makes such expansion less anisotropic. This article is protected by copyright. All rights reserved.

3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin.

Stability constants for the inclusion complexes of cyclohexylphthalimide 2 and adamantylphthalimide 3 with β-cyclodextrin (β-CD) were determined by 1H NMR titration, K = 190 ± 50 M−1, and K = 2600 ± 600 M−1, respectively. Photochemical reactivity of the inclusion complexes 2@β-CD and 3@β-CD was investigated, and we found out that β-CD does not affect the decarboxylation efficiency, while it affects the subsequent photochemical H-abstraction, resulting in different product distribution upon irradiation in the presence of β-CD. The formation of ternary complexes with acrylonitrile (AN) and 2@β-CD or 3@β-CD was also essayed by 1H NMR. Although the formation of such complexes was suggested, stability constants could not be determined. Irradiation of 2@β-CD in the presence of AN in aqueous solution where cycloadduct 7 was formed highly suggests that decarboxylation and [3 + 2] cycloaddition take place in the ternary complex, whereas such a reactivity from bulky adamantane 3 is less likely. This proof of principle that decarboxylation and cycloaddition can be performed in the β-CD cavity has a significant importance for the design of new supramolecular systems for the control of photoreactivity.

Ce(IV)-ion initiated grafting of 1,3 galactomannan biopolymer with acrylonitrile

Galactomannans based biopolymers are common constituents of ungerminated seeds of numerous leguminous plants present in endosperm of seeds. They are highly valuable in industries due to their ability to modify the flow behavior of aqueous solutions viz. thicken, suspend, gel, stabilize, swell and film formation. Consequently, they have diverse applications in food and non-food due to their biocompatibility, biodegradability, sustainability and abundance. Cassia occidentalis, an annual weed occurring throughout India is a rich source of seed galactomannans (∼30% endosperm). The gum derived from seed endosperm can be potentially utilized in a number of industries to replace the conventional expensive gums. However, the extracted gum has considerable disadvantages such as uncontrolled hydration, changes in viscosity during storage, pH-dependent solubility, lower shelf life etc, thereby, limiting their vast industrial applications. Intriguingly, these limitations can be overcome by functionalization of hydroxyl groups. Therefore, grafting onto C. occidentalis seed gum was carried out with acrylonitrile in presence of ceric ammonium nitrate under inert atmosphere. The reaction conditions were optimized by varying concentration of CAN, nitric acid, acrylonitrile, reaction temperature and time. The grafted gum was characterized using FTIR, TGA, DTG, X-Ray and SEM analysis.

Molecular Modeling of Mechanisms of Decomposition of Ruthenium Metathesis Catalysts by Acrylonitrile

We report a computational mechanistic study explaining the low stability of Hoveyda–Grubbs catalyst in the presence of acrylonitrile. We show the atomistic and energetic basis of why recently synth...

Sorption of Pb(II), Cu(II), Fe(II) and Cr(VI) metal ions onto cross-linked graft copolymers of chitosan with binary vinyl monomer mixtures

Novel adsorbents for sorption of Pb(II), Cu(II), Fe(II) and Cr(VI) metal ions from waste water were synthesized by simultaneous cross-linking and graft copolymerization of chitosan (Ch) with N-isopropyl acrylamide (NIPAM) and its binary comonomers acrylic acid, acrylamide and acrylonitrile in presence of azo-bis(isobutyronitrile) (AIBN) as free radical initiator and N,N′-methylene bisacrylamide (MBA) cross-linker. FTIR, XRD, SEM and TGA/DTA techniques were used to describe the structural aspects of cross-linked graft copolymers. The improvement in swelling properties of the synthesized hydrogels was utilized to explore their potential for sorption of toxic metal ions from aqueous solutions. Metal ion sorption by synthesized cross-linked adsorbents was studied as a function of the change in contact time, pH, temperature and concentration of metal ions from a solution of individual metal ions. Selective sorption of metal ions was performed by immersing polymeric samples in a solution containing four metal ions in the same concentration. Candidate polymers showed preferential sorption of metal ions in order of Cu(II)>Pb(II)>Fe(II)>Cr(VI) ions. Cross-Ch-g-poly(NIPAM-co-AAc), Cross-Ch-g-poly(NIPAM-co-AAm) and Cross-Ch-g-poly(NIPAM), showed best results for sorption of all ions from single and four component solutions.

Deamination and decarboxylation of L-thyroxine by Chloroamine-T (CAT) in acidic medium: A mechanistic and kineitc study

In this manuscript, we report a spectrophotometric study (at 25°C) of oxidation of L-thyroxine by Chloramine T and their mechanistic pathway. The reactions are first-order with respect to both LTX and CAT. Protonated Chloramine-T, TsNHCl, have been suggested as the reactive species of CAT. The Stochiometry of the reaction is 1 : 1. The main products, 2-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl] acetaldehyde was separated, and identified by column chromatography, TLC and FT-IR. The reaction fails to initiate polymerization in the presence of acrylonitrile under the experimental conditions employed. Investigations of the reaction at different temperatures allowed the determination of the activation parameters and a tentative reaction mechanism in good consistency with the kinetic results is discussed.

A Mechanistic Studies of Mn(II) Catalyzed Oxidation of a Gabapentin by Peroxomonosulphate in Aqueous Alkaline Medium

Abstract A mechanistic approach to the influence of Mn(II) catalyzed oxidative deamination of an anti-convulsant drug [GP] by peroxomonosulphate (PMS) at a constant ionic strength of 1.0 mol dm –3 have been studied, spectrophotometrically. The reaction shows first order dependence on [PMS] and [Mn(II)] and apparent less than unit order dependence each in [GP] and alkali concentrations. Influence of dielectric constant and ionic strength of the medium on the reaction rate have been evaluated. It was observed that the added sulphate ion, the reduction product of the oxidant, had insignificant effect on the reaction rate. The reaction stoichiometry and oxidation products deprotonated GP, SO4 2− and MnO2 have been identified and a suitable mechanism has been proposed. The reaction fails to initiate polymerization in the presence of acrylonitrile under the experimental conditions employed. In a composite equilibrium step, deprotanated GP binds to catalyst and form a complex C that subsequently decomposes with oxidant to yield the products. Investigations of the reaction at different temperatures allowed the determination of the activation parameters and a tentative reaction mechanism in good consistency with the kinetic results is discussed.

Acrylonitrile-contamination induced enhancement of formic acid electro-oxidation at platinum nanoparticles modified glassy carbon electrodes

Minute amount (∼1 ppm) of acrylonitrile (AcN), a possible contaminant, shows an unexpected enhancement for the direct electro-oxidation of formic acid (FAO) at Pt nanoparticles modified GC (nano-Pt/GC) electrodes. This is reflected by a remarkable increase of the current intensity of the direct oxidation peak (Ipd, at ca. 0.3 V) in the presence of AcN, concurrently with a significant decrease of the second (indirect) oxidation current (Ipind, at ca. 0.7 V), compared to that observed in the absence of AcN (i.e., at the unpoisoned Pt electrode). The extent of enhancement depends on the surface coverage (θ) of AcN at the surface of Pt nanoparticles. AcN is thought to favor the direct FAO by disturbing the contiguity of the Pt sites, which is necessary for CO adsorption. Furthermore, XPS measurements revealed a change in the electronic structure of Pt in presence of AcN, which has a favorable positive impact on the charge transfer during the direct FAO.

Catalyst usage of micro concentration of Mn(II) for the oxidation of biotin by peroxomonosulphate in aqueous medium:A mechanistic approach

In this paper provides the mechanistic investigation of Mn(II)-catalyzed oxidative of biotin (BTN) has been studied by peroxomonosulphate (PMS) in alkaline medium at 293–308K with a constant ionic strength. Such studies are much helpful in gaining an insight into the interaction of metal ions through the study of the mechanistic pathway of biotin in redox reactions. The stoichiometry of the reaction is 1:1 in the presence of catalyst. The reaction shows polymerization in the presence of acrylonitrile under the experimental conditions employed. Influence of dielectric constant and ionic strength of the medium on the reaction rate have been done. Manganese peroxide was proposed as the intermediate to explain the experimental observations. Temperature effect is noticeable in all these reactions and activation parameters have been determined. The effect of temperature was evaluated by Arrhenius equation and transition state theory, a mechanism was proposed based on the observation of the experimental results. It involves the formation of an activated complex, which decomposes to give the product. It is identified with the help of FTIR and TLC.

Polyacrylonitrile reinforced PVA based-polymeric networks: Structural, morphological, and mechanical aspects

Various bioengineering and industrial applications demand hard, tough, and mechanically strong polymeric blends. A novel combination of polyvinyl alcohol (PVA) and polyacrylonitrile was used to synthesize semi-IPNs using redox polymerization method in order to achieve desired property combinations in terms of toughness, generally not found in a single polymeric material. The synthesized end products in the form of polymer matrix were characterized by FTIR spectral analysis in order to confirm the incorporation of PAN into PVA, while the morphological aspects studied by AFM analysis showed fair compatibility between the component polymers exhibiting quite smooth surface and nanosize domains. Microhardness investigations were undertaken using the Vicker's indentation technique and the results were analyzed in terms of strain hardening phenomenon. Increase in surface hardness was observed as a result of variation of PVA content within the gel matrix whereas the presence of acrylonitrile as the second network was found to impart toughness as observed by the tensile strength measurements. POLYM. ENG. SCI., 54:2579–2586, 2014. © 2013 Society of Plastics Engineers

Microwave Assisted Synthesis of Polyacrylonitrile/Ferrite Nanocomposites

A microwave (MW) assisted green process to synthesize nanomagnetic polymer composites (NPCs) based on polyacrylonitrile (PAN) has been developed. The process involves 2,2-azobisisobutyronitrile initiated in-situ polymerization of acrylonitrile in presence of tween -20 stabilized ferrite nanoparticles (FNPs) under MW irradiation ranging 25 to 100 Watt over 10min. With MW power, the polymerization reaction has been progressed resulting in NPCs with enhanced rheovis- cosity and yield over PAN. The formation of NPCs has been ascertained through Fourier transformed infra-red spectra, X ray diffraction and atomic force microscopy .Vibrating sample magnetometry and simultaneous thermogravimetric-differential thermal analysis-differential thermogravimetry reveals the formation of thermally stable NPCs with saturation magnetization 70.0 emu/g.

Electrosynthesis of cyclopropanes at the electrolysis of solutions of methyl esters of Di- and trichloroacetatic acids in aprotic media in the presence of acrylonitrile

The potentiostatic (galvanostatic) electrolysis of methyl esters of trichloroacetic acid on mercury (steel) cathodes in the cathodic compartment of a diaphragm cell in the presence of acrylonitrile affords a mixture of two stereoisomers of methyl ester of 1-chloro-2-cyanocyclopropanecarboxylic acid. The process involves a stage of dehalogenation of the original methyl ester followed by the reaction of the formed anion with acrylonitrile and proceeds more efficiently on a mercury cathode in the dimethylformamide medium with the current efficiency of 94% and the substance yield of 25%. In contrast to methyl trichloroacetate, the electrolysis of methyl dichloroacetate proceeds by an indirect mechanism involving its deprotonation on the steel cathode and by the cleavage of the C-Cl bond on the mercury cathode. In both cases, the acrylonitrile addition leads to formation of the corresponding cyclopropane structures. Moreover, the process is the most efficient on the steel cathode in the MeCN medium. In the latter case, the current efficiency of methyl ester of 1-chloro-2-cyanocyclopropanecarboxylic acid is 31% and substance yield is 41%. Peculiarities of these processes are discussed.

Synthesis and characterization of polyacrylonitrile pregelled starch graft copolymers using ferrous sulfate‐hydrogen peroxide redox initiation system as surface sizing agent

AbstractA graft copolymer was synthesized by graft copolymerization of starch with styrene (St) and butyl acrylate (BA), using ferrous sulfate‐hydrogen peroxide redox initiation system. The starch was pregelled in the presence of acrylonitrile (AN) in aqueous alkali at high temperature before graft polymerization. Major factors affecting the polymerization reaction were investigated. It was found that a graft copolymer with higher percentage conversion (PC), graft efficiency (GE) and graft percentage (GP) was obtained by controlling the initiator concentration, concentration, and ratio of monomers and polymerization temperature. The optimum conditions were as follows: H2O2 concentration, 12%; monomer concentration, 120%; St/BA ratio, 1 : 1; polymerization temperature, 65°C. Fourier transform infrared spectroscopy and NMR analyses were used to gain information on the structure of the products. It was demonstrated that St, BA, and AN had been successfully grafted onto starch and CN had been saponified into CONH2 and COO− to a certain degree when pregelling. Scanning electron microscope micrographs showed the coarse structure and broad network. The graft polymerization took place on the surface of starch granule and led to amorphization of the starch structure. Graft polymer had better thermal stability and was endowed with pseudo‐plasticity. It was observed that the starch graft copolymer offers good properties such as water resistance as surface‐sizing agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Effect of solvents on cyanoethylation of cotton cellulose and its properties

AbstractThe cyanoethylation of cotton fabric was carried out using aqueous sodium hydroxide with acrylonitrile in presence of solvents like acetone and ethanol in different concentrations. The modified cellulose was investigated with vertical wicking test, X‐ray diffraction (XRD), thermogravimetry‐differential thermal analysis (TG/DTA), and atomic force microscopy (AFM). The wicking height was increased for the modified cellulose. Modified cellulose had increase in crystallinity index with reduction of crystallite size. The thermal stability of the modified cellulose was also increased. The images produced using AFM technique revealed that there is appreciable difference in the surface roughness between scoured, mercerized, cyanoethylated and solvent treated samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

ChemInform Abstract: Synthesis of C-1 Spirocyclopropyl Sugars from Anomeric Diazides.

Abstract The photolysis of peracetylated glucopyranosylidene diazide in the presence of acrylonitrile in excess yields four C-1 spirocyclopropyl sugars in a 65% combined yield. This unprecedented synthesis of bis C,C-glycosides is supposed to inlvolve anomeric carbene intermediates.

Combination of AlCl3, Ionic Liquid, and Microwaves: An Efficient Method for Dehydration and 1,3-Dipolar Cycloaddition: An Unusual Observation in the Presence of Acrylonitrile

Use of a combination of ionic liquids in the presence of aluminium chloride and microwave irradiation was shown to be a very efficient and high-yielding method for the dehydration of aldoximes and also for 1,3-dipolar cycloadditions. Surprisingly, the presence of acrylonitrile rendered an unusual formation of substituted amide.

High Water Absorbents from Lignocelluloses. Part III: Upgrading the Utilization of Old Newspaper [ONP] in Agronomic Application

A study of converting ONP into hydrogel was undertaken to develop a new approach in effective utilization of waste paper. This hydrogel was prepared using environmental friendly process based on graft polymerization reaction with acrylonitrile in presence of redox system initiator. The prepared hydrogel was evaluated as soil conditioner from the properties of the treated sandy soil, e.g., bulk density and porosity, volume distribution of pores, water holding pores and fine capillary pores, available moisture, air field porosity and water stable structural units, in comparison to those hydrogels previously prepared from sugar-cane bagasse and with conventional soil conditioners (organic fertilizer and bentonite). Enhancing the behavior of the prepared ONP hydrogel as soil conditioner in the agronomic application, through plant transplanting in sandy soil was also investigated. The evaluation was performed by measuring seed germination and plant moisture stress of Squash (Cucurbita pepo) plant.