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Dalton Transactions (Cambridge, England... May 2023Nitriles, particularly acrylonitrile and acetonitrile, are versatile chemicals that are used in various fields, such as polymer synthesis and pharmaceutical production.... (Review)
Review
Nitriles, particularly acrylonitrile and acetonitrile, are versatile chemicals that are used in various fields, such as polymer synthesis and pharmaceutical production. For a long time, acrylonitrile has been produced propylene ammoxidation with acetonitrile as a byproduct. The depletion of crude reservoirs and the production of unconventional hydrocarbon resources (, shale gas) renders light alkanes (including propane, ethane, and methane) to be potential feedstocks in the syntheses of acrylonitrile and acetonitrile. In this review, the processes of transforming light hydrocarbons to nitriles are surveyed, the developments in nitrile synthesis from alkanes are discussed, and the existing challenges and plausible solutions are addressed.
PubMed: 36883519
DOI: 10.1039/d2dt03795e -
The Science of the Total Environment Mar 2021In this study the occurrence, morphology and identification of microplastics in Black Sea sediments collected at different depths (range 22-2131 m) were determined for...
In this study the occurrence, morphology and identification of microplastics in Black Sea sediments collected at different depths (range 22-2131 m) were determined for the first time. The study explored the advantages and limitations of using a non-invasive method consisting of filtration of the supernatant from the mixture of sediment with saturated NaCl solution followed by FTIR 2D imaging for the identification of natural and synthetic polymers. The proposed method confirmed its potential for clear identification of polyethylene, polypropylene, acrylonitrile, polyamides and cellulose-based fibers, but more difficulties when the filter substrate neighboring the fibers exhibits intense absorptions in the 1800-1000 cm range. Microplastics (MPs) were determined in 83% of the investigated sediment samples. The average abundance in all samples was 106.7 items/kg. The highest pollution occurred on the North-Western shelf where the abundance of MPs was 10 times higher than in sediments from the deep sea. The most abundant plastic polymers were polyethylene and polypropylene, followed by acrylate and acrylonitrile copolymers. Polyamide and cellulose-based textile fibers were also found. The most frequent microplastic colors observed were black, blue and clear/transparent, while fibers represented the dominant microplastics in sediments.
PubMed: 33341641
DOI: 10.1016/j.scitotenv.2020.143898 -
The Journal of Chemical Physics Jul 2023The ion-molecule reaction is one of the most important pathways for the formation of new interstellar chemical species. Herein, infrared spectra of cationic binary...
The ion-molecule reaction is one of the most important pathways for the formation of new interstellar chemical species. Herein, infrared spectra of cationic binary clusters of acrylonitrile (AN) with methanethiol (CH3SH) and dimethyl sulfide (CH3SCH3) are measured and compared to those previous studies of AN and methanol (CH3OH) or dimethyl ether (CH3OCH3). The results suggest that the ion-molecular reactions of AN with CH3SH and CH3SCH3 only yield products with S…HN H-bonded or S∴N hemibond structures, rather than the cyclic products as observed in AN-CH3OH and AN-CH3OCH3 studied previously. The Michael addition-cyclization reaction between acrylonitrile and sulfur-containing molecules does not occur due to the weaker acidity of CH bonds in sulfur-containing molecules, which results from their weaker hyperconjugation effect compared to oxygen-containing molecules. The reduced propensity for the proton transfer from the CH bonds hinders the formation of the Michael addition-cyclization product that follows.
Topics: Acrylonitrile; Gases; Protons; Sulfur
PubMed: 37417750
DOI: 10.1063/5.0154135 -
Chemical Science Oct 2020There is a widespread perception that the high level of selectivity witnessed in many Diels-Alder reactions is an intrinsic feature of the transformation. In contrast...
There is a widespread perception that the high level of selectivity witnessed in many Diels-Alder reactions is an intrinsic feature of the transformation. In contrast to expectations based upon this existing belief, the first experimental Diels-Alder reactions of a novel, deuterium-labeled 1,3-butadiene with commonly used mono-substituted alkenic dienophiles (acrolein, methyl vinyl ketone, acrylic acid, methyl acrylate, acrylamide and acrylonitrile) reveal kinetic : ratios close to 1 : 1. Maleonitrile, butenolide, α-methylene γ-butyrolactone, and -methylmaleimide behave differently, as does methyl vinyl ketone under Lewis acid catalysis. CBS-QB3 calculations incorporating solvent and temperature parameters give : product ratios that are in near quantitative agreement with these and earlier experimental findings. This work challenges the preconception of innate -selectivity by providing the first experimental evidence that the simplest Diels-Alder reactions are not -selective. Trends in behaviour are traced to steric and electronic effects in Diels-Alder transition structures, giving new insights into these fundamental processes.
PubMed: 34123213
DOI: 10.1039/d0sc04553e -
Respiratory Medicine Dec 2022Volatile organic compounds (VOCs) are associated with adverse respiratory outcomes at high occupational exposures. However, whether exposure levels found in the general...
BACKGROUND
Volatile organic compounds (VOCs) are associated with adverse respiratory outcomes at high occupational exposures. However, whether exposure levels found in the general population have similar effects is unknown.
METHODS
We analyzed data on 1342 adult participants in the 2011-2012 National Health and Nutrition Examination Survey aged ≥18 years old who had urinary VOC metabolites and spirometry measurements available. Linear regression models adjusting for covariates were fitted to estimate the associations of VOC exposures levels and spirometry outcomes, while accounting for survey design and sampling weights to generate nationally representative estimates.
RESULTS
The urinary metabolites for xylene, acrylamide, acrolein, 1,3-butadiene, cyanide, toluene, 1-bromopropane, acrylonitrile, propylene oxide, styrene, ethylbenzene, and crotonaldehyde in our analysis were all detected in >75% of participants. Forced expiratory volume in 1 s (FEV) to forced vital capacity (FVC) ratio % was lower with urinary metabolites of acrylamide (β: -2.65, 95% CI: -4.32, -0.98), acrylonitrile (β: -1.02, 95% CI: -2.01, -0.03), and styrene (β: -3.13, 95% CI: -5.35, -0.90). FEV% predicted was lower with the urinary metabolites of acrolein (β: -7.77, 95% CI: -13.29, -2.25), acrylonitrile (β: -2.05, 95% CI: -3.77, -0.34), propylene oxide (β: -2.90, 95% CI: -5.50, -0.32), and styrene (β: -4.41, 95% CI: -6.97, -1.85).
CONCLUSIONS
This is the first study of a representative sample of the U.S. adult population to reveal associations of acrylonitrile, propylene oxide, and styrene urinary metabolites with reduced lung function at non-occupational exposures. Results also support previous evidence of acrylamide and acrolein's association with adverse respiratory outcomes.
Topics: Adult; Humans; Adolescent; Volatile Organic Compounds; Nutrition Surveys; Acrylamide; Styrene; Lung
PubMed: 36399896
DOI: 10.1016/j.rmed.2022.107053 -
Journal of Colloid and Interface Science Dec 2022Silver nanoclusters of five atoms (Ag) display outstanding catalytic activities for the deactivation of radicals. Using 2,2-diphenyl-1‑picrylhydrazyl (DPPH) radical as...
Silver nanoclusters of five atoms (Ag) display outstanding catalytic activities for the deactivation of radicals. Using 2,2-diphenyl-1‑picrylhydrazyl (DPPH) radical as a model system, we observed a fast radical reduction to DPPH anions using only [Ag] 3 to 4 orders of magnitude less than [DPPH]. Moreover, nanoclusters remain stable at the end of the reaction, and can deactivate again DPPH radicals at the same rate, indicating that they act as anti-radical catalysts. The radical scavenger catalytic activity of Ag proceeds selectively through the oxidation of methanol (used to dissolve the radical) to formaldehyde, which is supported by DFT calculations. The obtained catalytic rate constants are almost 2 orders of magnitude higher than oxidases, and more than 4 orders of magnitude larger than graphene quantum dots. We also show that Ag not only catalyze the reduction of radicals but also their oxidation, promoting the inhibition of the autoxidation mechanisms of hydrocarbon polymers, which are very sensitive to the presence of radicals. For this purpose, thin films of two industrially relevant polymers (polyisoprene and acrylonitrile-butadienestyrene copolymer), were exposed to standard simulated photo-ageing conditions in the presence of Ag. Using Attenuated Total Reflection-FTIR and DFT modeling we observed that, although Ag nanoclusters, with ≈ 15% surface coverage, do not totally inhibit the oxidation, they favour a decomposition that yields inactive products, in contrast with the more detrimental ketone formation pathway. These results not only open new possibilities for developing a post-process inhibition of polymer degradation, for which nowadays there are no efficient procedures, but also, they could be used as very efficient dual-redox catalytic radical scavengers for different industrial or biomedical purposes.
Topics: Acrylonitrile; Anions; Biphenyl Compounds; Formaldehyde; Graphite; Ketones; Methanol; Oxidation-Reduction; Oxidoreductases; Polymers; Silver
PubMed: 35932680
DOI: 10.1016/j.jcis.2022.07.133 -
The Journal of Physical Chemistry. A Nov 2020The high-resolution absorption spectrum of 3-methoxyacrylonitrile (3MAN) was measured between 5.27 and 12.59 eV using a synchrotron-based Fourier-transform spectrometer....
The high-resolution absorption spectrum of 3-methoxyacrylonitrile (3MAN) was measured between 5.27 and 12.59 eV using a synchrotron-based Fourier-transform spectrometer. It was related to an absolute absorption cross-section scale. Complementary calculations at the DFT-MRCI/aug-cc-pVTZ level of theory document the vertical transition energies and oscillator strengths toward the first 19 states of both the and geometrical isomers of 3MAN. Comparisons with the experimental absorption spectrum reveal the similarities and differences between 3MAN, a bifunctional molecule, with acrylonitrile and methylvinylether, where only one functional group is present. As in acrylonitrile, several broad valence transitions were observed up to the ionization limit. They are likely associated with the extended π-system induced by the nitrile group but might also involve σσ* transitions close to the ionization limit. As in methylvinylether, Rydberg series converging to the ionization limit are absent. This is attributed to a difference in neutral and cationic geometry due to a 60° rotation of the methyl group.
PubMed: 33131274
DOI: 10.1021/acs.jpca.0c08974 -
Heliyon Dec 2022Ethylene-propylene grafted-maleic anhydride (EPR-g-MA) and a pure maleic anhydride (MA) were separately used to compound carboxylated acrylonitrile butadiene-rubber...
Ethylene-propylene grafted-maleic anhydride (EPR-g-MA) and a pure maleic anhydride (MA) were separately used to compound carboxylated acrylonitrile butadiene-rubber (XNBR) together with reduced graphene oxide (G) to form nanocomposites, by using melt compounding technique. The G-sheets in the presence of MA (GA samples) or EPR-g-MA (GB samples) generally increased the physico-mechanical properties including; crosslinking density, tensile strength and thermal degradation resistance etc., when compared with sample without MA or EPR-g-MA (GAO) and the virgin matrix. For the thermal degradation resistance measured by the char residue (%), by using thermal gravimetric analysis technique; GA1 (0.1 ph G and 0.5 ph MA) was 106.4% > XNBR and 58% > GAO (0.1 ph G) while that of GB1 (0.1 ph G and 0.5 ph EPR-g-MA) was 60% > XNBR and 22.2% > GAO respectively. Although, homogeneous dispersions of the G-sheets assisted by MA or EPR-g-MA was a factor, but the strong bonding (covalent, hydrogen and physical entanglements) occurring in GA and GB was observed to be the main contributing factor for these property enhancements. Thus, these nanostructured materials have exhibited multifunctional capabilities and could be used for advanced applications including high temperature (heat sinks), flame retardants, and structural applications.
PubMed: 36478802
DOI: 10.1016/j.heliyon.2022.e11974 -
Organic Letters May 2023The merger of two bifunctional moieties, 2-alkynylaniline and alkynylnitriles, in the presence of ZnBr offers the tunable synthesis of two biologically important motifs:...
The merger of two bifunctional moieties, 2-alkynylaniline and alkynylnitriles, in the presence of ZnBr offers the tunable synthesis of two biologically important motifs: acrylonitrile indoles and 3-cyanoquinolines. The group present on the terminal alkyne of 2-alkynylaniline regulates the reaction pathways, intra- versus intermolecular, which thereby adds stereoselectivity and regioselectivity in this protocol. The conversion of an acrylonitrile indole ring to quinoline is an intriguing synthetic utility of this methodology.
PubMed: 37126068
DOI: 10.1021/acs.orglett.3c00987 -
ChemistryOpen Oct 2022Antibiotic resistance is now a growing threat to human health, further exacerbated by the lack of new antibiotics. We describe the practical synthesis of a series of...
Antibiotic resistance is now a growing threat to human health, further exacerbated by the lack of new antibiotics. We describe the practical synthesis of a series of substituted polyamine succinamides and branched polyamines that are potential new antibiotics against both Gram-positive and Gram-negative bacteria, including MRSA and Pseudomonas aeruginosa. They are prepared via 1,4-Michael addition of acrylonitrile and then hydrogenation of the nitrile functional groups to primary amines. They are built upon the framework of the naturally occurring polyamines thermine (3.3.3, norspermine) and spermine (3.4.3), homo- and heterodimeric polyamine succinic amides. Linking two of the same or different polyamines together via amide bonds can be achieved by introducing a carboxylic acid group on the first polyamine, then coupling that released carboxylic acid to a free primary amine in the second polyamine. If the addition of positive charges on the amino groups along the polyamine chains are a key factor in their antimicrobial activity against Gram-negative bacteria, then increasing them will increase the antimicrobial activity. Synthesising polyamine amide dimers will increase the total net positive charge compared to their monomers. The design and practical synthesis of such homo- and hetero-dimers of linear polyamines, spermine and norspermine, are reported. Several of these compounds do not display significant antibacterial activity against Gram-positive or Gram-negative bacteria, including MRSA and Pseudomonas aeruginosa. However, the most charged analogue, a branched polyamine carrying eight positive charges at physiological pH, displays antibiofilm activity with a 50 % reduction in PAO1 at 16-32 μg mL .
Topics: Humans; Polyamines; Spermine; Gram-Negative Bacteria; Anti-Bacterial Agents; Gram-Positive Bacteria; Acrylonitrile; Amides; Carboxylic Acids
PubMed: 36284254
DOI: 10.1002/open.202200147