INFRARED spectra, BENZENE, OPTICAL constants, ABSORPTION coefficients, and ORGANIC chemistry
Infrared spectroscopic results on benzene (C 6 H 6) ices from two recent papers, one published here, are compared to each other and to literature results from 60 years ago. Qualitative and quantitative differences are described, partly in terms of spectral resolution, and errors in one paper are identified that, once corrected, could bring the two recent publications into agreement with each other. A solution is provided for an unexplained disagreement with the literature noted by the authors of one paper. It is concluded that the only accurate, extensive set of IR absorption coefficients, band strengths, and optical constants now available for amorphous and crystalline benzene are those recently published here by the author and a colleague. Suggestions are made for future work to change this situation. • Laboratory results from two recent papers on benzene ices are compared. • Multiple tests suggest conflicting results and possible corrections to them. • The data can lead to determinations of molecular abundances in extraterrestrial ices. [ABSTRACT FROM AUTHOR]
Hydrodesulfurization is well established in the industry while costly and environmentally unfriendly due to CO 2 emissions and H 2 S production. An alternative, cost-effective desulfurization process remains unreported. Here, we demonstrate a desulfurization process for dibenzothiophene, one of the most well-known and recalcitrant sulfur-containing model compounds against catalytic desulfurization, under the regulation of methane instead of hydrogen over a combination of two catalysts, generating a new sulfur-containing product, CS 2 , as an important intermediate in organic chemistry and non-polar solvent with lower environmental impact than H 2 S. A catalytic mechanism is proposed and supported by extensive experimental and computational evidence. It is discovered that methane acts as a critical initiator and intensifies the direct desulfurization pathway, where two catalysts must work cooperatively and a surface sulfur transfer process is indispensable. This study explores an alternative desulfurization route with unique reaction pathways towards CS 2 formation, whose practical potential is also supported by the desulfurization performance over a series of real-world crude samples. [Display omitted] • Methane-regulated catalytic desulfurization of dibenzothiophene is realized. • Methane initiates a direct desulfurization pathway and ends up in final products. • Carbon disulfide is observed as an environmentally benign sulfur-containing product. • A dual catalyst system is designed and the mechanism is proposed and verified. • Real-world sample desulfurization practices confirm the technical feasibility. [ABSTRACT FROM AUTHOR]
The H 2 SO 4 -based imidazole ionic liquids performed as phase-separation catalysts for the esterification of trimethylolpropane and acrylic acids, exhibiting the best trimethylolpropane conversion (100%) and trimethylolpropane acrylate selectivity (86.4%). [Display omitted] • H 2 SO 4 -based ionic liquids were applied as catalysts for esterification of trimethylolpropane and acrylic acid. • A novel phase-separation catalytic process was observed during the reaction. • 100% of trimethylolpropane conversion and 86.4% of trimethylolpropane acrylate selectivity were achieved. • The phase-separated ionic liquids can be steadily reused. Trimethylolpropane acrylate (TMPTA) is becoming an important organic chemistry intermediate, but it's synthesis through the acid-catalyzed esterification of trimethylolpropane and acrylic acid is a challenge due to the poor activity and catalyst separation problems. In this work, a series of 1,3-propanesultone (PS)-functionalized imidazole ionic liquids (ILs) are prepared and evaluated as the acid catalysts for this reaction, including the catalytic performance comparison, optimization of reaction conditions, and the catalytic reusability. The obtained H 2 SO 4 -based IL ([IMPSH]HSO 4) caused a phase-separation catalytic process (reacted as a homogeneous catalyst, but precipitated at the end of reaction like a heterogeneous catalyst), presenting the best trimethylolpropane conversion (100%) and TMPTA selectivity (86.4%). Such catalytic performance is even better than that of homogeneous H 2 SO 4. Moreover, the catalyst can be steadily reused at least four times without obvious change in activity and its structure. The highly efficient and environmentally benign performance of [IMPSH]HSO 4 -catalyzed esterification of trimethylolpropane and acrylic acid make it possible to achieve industrial applications. [ABSTRACT FROM AUTHOR]
Kuterasiński, Ł., Kurowski, G., Jeleń, P., Sitarz, M., and Jodłowski, P.J.
Journal of Molecular Structure. Aug2022, Vol. 1261, pN.PAG-N.PAG. 1p.
CATALYSTS, CYCLOHEXENE, ORGANIC chemistry, CHEMICAL reactions, CERIUM oxides, and CATALYTIC oxidation
• Ultrasonic impregnation of Co, Ce or Co-Pd active phase on γ-Al 2 O 3 is presented. • Ultrasounds influences higher metal distribution and smaller crystallites and grains. • Characterization methods indicate Co as Co 3 O 4 or CoAl 2 O 4 and Ce in the form of CeO 2. • The addition of Pd to Co/γ-Al 2 O 3 do not influence the status of cobalt. • Ultrasonic irradiation increases surface area and decreases pore size and pore volume. The oxidation of cyclohexene belongs to the most important reactions in organic chemistry and leads to the production of the precursors for surfactants, polymers, agrochemicals, and drugs. So far, however, due to a complex reaction mechanism, it was hard to find the catalyst of satisfactory properties. Attractive catalysts in this reaction could be sonochemically prepared Co, Ce, and Pd containing γ-Al 2 O 3 , which is the object of the undertaken research. What is more, this combination of metals in the oxide system has not been studied. The analysis of catalytic performance indicated that all studied catalysts were active in the catalytic oxidation of cyclohexene. For metal-containing alumina (Me=Co, Ce, Pd), the conversion of cyclohexene was 61–84%. The best catalyst was Co 5 Ce 5 /γ-Al 2 O 3 s , prepared via the sonochemically-assisted procedure. It was also shown that the application of ultrasonic irradiation during the preparation of samples enhanced metal distribution over alumina support, resulted in smaller crystallites of prepared materials, and caused higher surface area with simultaneous smaller both pore size and pore volume in comparison with counterparts prepared via the standard procedure. XRD, Ra, and DR..-UV–vis spectroscopies indicated the coexistence of Co as Co 3 O 4 and CoAl 2 O 4 spinel, however, Ce was found in the form of CeO 2. The addition of Pd to Co/γ-Al 2 O 3 did not influence the status of cobalt. [Display omitted] [ABSTRACT FROM AUTHOR]
Polyacrylamide-based waterborne microgels were prepared with copolymerized carboxylic acid and tertiary amine moieties. The colloidal gels were loaded with palladium nanoparticles and utilized for the Suzuki–Miyaura cross-coupling of amino acids and peptides. The thermoresponsive properties of the prepared microgels were characterized by means of photon correlation spectroscopy (PCS) at solvent conditions of the catalytic reaction. The localization and morphology of the incorporated nanoparticles were characterized with transmission electron microscopy (TEM). Palladium-catalyzed Suzuki–Miyaura cross-coupling of N α-Boc-4-iodophenylalanine and N α-Boc-7-bromotryptophan with phenylboronic acid was carried out under ambient atmosphere in water at 20, 37, and 60 °C, respectively. The properties of the thermoresponsive microgel showed a strong influence on the reactivity and selectivity towards the respective substrate. For the amine containing microgels, a recyclability for up to four cycles without loss in activity could be realized. Furthermore, the systems showed good catalytic activity regarding Suzuki–Miyaura cross-coupling of halogenated amino acids in selected tri- and tetrapeptides. [ABSTRACT FROM AUTHOR]
New Journal of Chemistry. 7/7/2022, Vol. 46 Issue 25, p12103-12119. 17p.
ORGANIC chemistry, MOLECULAR recognition, CHEMICAL reactions, METAL ions, IONS, RHODAMINES, and METHYLMERCURY
Alkyne is a versatile functional group in organic chemistry, and is able to undergo a wide variety of reactions and interactions. Featuring a reactive functional group, alkyne participates in many organic reactions and hence a sharp rise in the interest of utilizing the alkyne functionality has made it an inevitable synthon in a wide domain of purposes and one of such purposes is molecular recognition. On account of this, two pyridine-derived scaffolds, 5 and 7, containing identical molecular cores but different appendages, viz., terminal alkyne (5) and internally 1,3-conjugated alkyne units (7), are successfully synthesized. Both the compounds are subjected to metal ion sensing at the molecular level and are found to bind Cu2+ and Hg2+ ions with different functionalities. Compounds 5 and 7 interact with Cu2+ by the pyridine N and the two adjacent amide N's in a tripodal fashion, whereas they interact with Hg2+ by their respective open-end and closed-end alkyne units. The terminal alkynes in 5 undergo chemical reaction in the presence of Hg(ClO4)2·H2O and get converted to a ketone functionality, while the internally conjugated 1,3-dialkyne unit in 7 acts as a binding unit for a Hg2+ ion. Both experimental studies and theoretical (DFT) calculations have converged on the result that terminal alkynes cannot function as a chemosensor for Hg2+ ions, although they can respond by functional group transformation, whereas cyclic internally conjugated alkynes can perform as potential Hg2+ sensors. The combination of Cu2+ and Hg2+ ions has been used to generate a molecular system exhibiting the OR logic operation. The limits of detection (LODs) of Cu2+ ions, obtained for 5 and 7, are 5.5 × 10−7 M and 5.2 × 10−7 M, respectively, and that of the Hg2+ ion for 7 is 4.4 × 10−7 M. The synthesized probes, as well as their complexes, are stable around neutral pH and the probes retain their sensitivity within a temperature window of 25–80 °C. This creates an avenue for differential recognition of multiple heavy metal ions simultaneously with similar molecular motifs. [ABSTRACT FROM AUTHOR]
ORGANIC chemistry, PINEAPPLE, CHEMICAL kinetics, WET chemistry, and RASPBERRY Pi
Ein Beitrag aus Kanada stellt eine schöne AR-App vor: B Developing a Simple and Cost-Effective Markerless Augmented Reality Tool for Chemistry Education b ( I J. Chem. Educ i . 2021, 98, 5, 1783-1788, https://pubs.acs.org/doi/full/10.1021/acs.jchemed.1c00173). Technologie inklusive Augmented (AR) und Virtual Reality (VR) Einen recht einfachen Versuchsaufbau zur Kolorimetrie stellen Lorean Madriz (email@example.com) et al. aus Argentinien vor: B Exploring Chemical Kinetics at Home in Times of Pandemic: Following the Bleaching of Food Dye Allura Red Using a Smartphone b ( I J. Chem. Educ i . 2021, 98, 6, 2117-212, https://pubs.acs.org/doi/full/10.1021/acs.jchemed.0c01427). BioSIM SP AR sp (https://ar.biosim.pt/) ist eine kostenlose Software zur Darstellung von 3D-Molekülen in einer AR-Umgebung: B Developing and Using BioSIM SP AR sp , an Augmented Reality Program to Visualize and Learn about Chemical Structures in a Virtual Environment on Any Internet-Connected Device b ( I J. Chem. Educ i . 2021, 98, 5, 1789-1794, https://pubs.acs.org/doi/10.1021/acs.jchemed.0c01317). [Extracted from the article]
Phthalides, an important class of bioactive natural products, are widely distributed in plants, fungi, lichens, and liverworts. Amon them, n -butylphthalide, a phthalide monomer, has been approved to cure ischemic stroke. Owing to their good bioactivities in anti-microbial, anti-inflammatory, anti-tumor, anti-diabetic, and other aspects, a large number of researches have been conducted on phthalides from nature materials. In recent years, hundreds of novel natural phthalides were obtained. This review provides profiles of the advances in the distribution, chemistry, and biological activities of natural phthalides in 2016–2022. [Display omitted] [ABSTRACT FROM AUTHOR]
Valletti, Nadia, Acar, Mert, Cucciniello, Raffaele, Magrini, Claudia, Budroni, Marcello A., Tatini, Duccio, Proto, Antonio, Marchettini, Nadia, Lo Nostro, Pierandrea, and Rossi, Federico
Journal of Molecular Liquids. Jul2022, Vol. 357, pN.PAG-N.PAG. 1p.
MEASUREMENT of viscosity, DIFFUSION coefficients, STABILITY constants, AQUEOUS solutions, ORGANIC chemistry, TEMPERATURE measurements, CARBONATE minerals, and GLYCERIN
[Display omitted] • Diffusivity, density and viscosity for GC in H 2 O were measured at 283.15 K–313.15 K. • The activation energy and the hydrodynamic parameters were calculated. • Data analysis suggests the formation of hydrogen bonded GC-GC dimers. • Formation constant, diffusivity and hydrodynamic radius were calculated for the dimer. Glycerol Carbonate (4-hydroxymethyl-2-oxo-1,3-dioxolane, GC) is an emerging green reactant for many organic chemistry applications. GC popularity stems from its high reactivity, which makes it attractive for many chemical transformations and for its easy synthesis from glycerol, a byproduct of biodiesel production. While extensive literature covers the synthesis and chemical reactivity of GC, its transport properties are poorly studied, especially in water. Here, we measured for the first time the diffusion coefficient of GC in water in the temperature range 283.15–313.15 K and for concentrations up to 0.1 M. By taking advantage of the Taylor Dispersion Analysis (TDA) we found D 0 = 9.53 ± 0.06 × 10 - 10 m2/s at 298.15 K and an activation energy for the diffusion process E a = 3.74 ± 0.09 kcal/mol. Density and dynamic viscosity were also measured in the same temperature interval to calculate the hydrodynamic radius of GC. Experimental data helped in assessing the structure of GC aggregates formed in aqueous solutions and provided an estimation of the equilibrium constant for the dimer formation. Our findings can be useful for studying the fate of GC in the environment and to improve its use for applications in aqueous media. [ABSTRACT FROM AUTHOR]
ALKENES, ORGANIC chemistry, ALKANES, HETEROARENES, NATURAL products, and ALCOHOL
Heteroarenes are important units in organic chemistry and are ubiquitous in natural products, pharmaceuticals, and numerous artificial molecules. Despite great efforts devoted to accessing heteroarenes, the development of new methods to efficiently produce heteroarenes remains a long-term interest. Recently, the strategy of radical-mediated heteroaryl migration has supplied a robust toolkit for the synthesis of a diversity of heteroaryl-containing compounds. This Account summarizes our recent achievements in this field and provides insight into the incorporation of heteroarenes into organic skeletons. 1 Introduction 2 Radical-Mediated Heteroarylation of Alkanes and Alkenes via Intramolecular Heteroaryl Migration 2.1 C(sp3)–H Heteroarylation via Intramolecular Heteroaryl Migration 2.2 Difunctionalization of Alkenes via Intramolecular Heteroaryl Migration 3 Intermolecular Difunctionalization of Alkenes via 'Docking-Migration' Strategy 3.1 Sulfone-Based Bifunctional Reagents for Difunctionalization of Alkenes by Docking Migration 3.2 Sulfone-Based Reagents for the Synthesis of N-Fused Heteroarenes by Docking Migration 3.3 Tertiary Alcohol Based Bifunctional Reagents for Difunctionalization of Alkenes by Docking Migration 3.4 Diaryl Ether Based Bifunctional Reagents for Difunctionalization of Alkenes by Docking Migration 3.5 Conclusion [ABSTRACT FROM AUTHOR]
In the Sharpless asymmetric epoxidation of chiral secondary allylic alcohols, one substrate enantiomer is predominantly converted to the anti‐epoxy alcohol. We herein report the first highly syn‐selective epoxidation of terminal allylic alcohols using a titanium salalen complex as catalyst, at room temperature, and aqueous hydrogen peroxide as oxidant. With enantiopure terminal allylic alcohols as substrates, the epoxy alcohols were obtained with up to 98 % yield and up to >99 : 1 dr (syn). Catalyst loadings as low as 1 mol % can be applied without eroding the syn‐diastereoselectivity. Modification of the allylic alcohol to an ether does not affect the diastereoselectivity either [>99 : 1 dr (syn)]. Inverting the catalyst configuration leads to the anti‐product, albeit at lower dr (ca. 20 : 1). The synthetic potential is demonstrated by a short, gram‐scale preparation of a tetrahydrofuran building block with three stereocenters, involving two titanium salalen catalyzed epoxidation steps. [ABSTRACT FROM AUTHOR]
Depressants are critical reagents for the selective separation of minerals in froth flotation. They serve a vital role in preferentially making the gangue minerals hydrophilic and prevent them from reporting to the mineral-rich froth phase. Current practice involves the use of inorganic depressants, which are toxic and non-biodegradable. Environmentally friendly, flexible and affordable flotation depressants are needed due to the depletion of easy-to-process high-grade ores as well as sustainability and environmental concerns. This paper discusses various organic depressants that have been adopted for selective depression of unwanted minerals in chalcopyrite flotation. The origin and chemistry, organic depressant-gangue minerals interaction mechanism, and the use of organic depressants in the most common chalcopyrite-flotation instances, including chalcopyrite separation from galena, molybdenite, sphalerite, pyrite, pyrrhotite, talc, serpentine and carbonaceous materials, are discussed. This review shows that organic depressants can partially or fully replace current inorganic depressants used in suppressing both sulfide and non-sulfide gangue minerals in chalcopyrite flotation. In this review, a well-detailed and well-referenced discussion is provided for the current state of organic depressants in chalcopyrite flotation, as well as a valuable discussion is provided to comparatively evaluate the depression performance of the various reported organic depressants. Finally, suggestions are made regarding future research challenges and directions. The recent advancements, developing features, and research prospects discussed in this article will provide a helpful reference for academics who want to delve deeper into the greening of chalcopyrite flotation process. [ABSTRACT FROM AUTHOR]
He, Xian, Qi, Jiayue, Chen, Menghao, Lv, Jiangbo, Xiao, Hang, Hu, Jianghuai, Zeng, Ke, and Yang, Gang
Polymer. Jun2022, Vol. 253, pN.PAG-N.PAG. 1p.
NUCLEOPHILIC reactions, NUCLEOPHILIC substitution reactions, BENZENEDICARBONITRILE, ORGANIC chemistry, CHEMICAL reactions, BISPHENOL A, SCHIFF bases, and SOLVENTS
Nucleophilic reactions, as extensive and easily implementable reactions in organic chemistry, play a significant role in the molecular design of organic compounds and polymer materials. In current sustainable development strategies, nucleophilic reactions are also being shifted towards green chemistry. In this paper, phthalonitrile (PN) resin, a thermoset prepared by nucleophilic substitution reaction, was selected for a case study to investigate the application and reusability of the 'green solvent' dimethyl carbonate (DMC) in the nucleophilic substitution reaction. This research employed naturally existing vanillin and tyramine for the synthesis of a fully bio-based bisphenol bearing a Schiff base structure (VTBP). Then VTBP was converted to a novel bio-based PN (VTPN) through a nucleophilic substitution reaction in DMC, and the DMC was recovered and reused through a rotary evaporation. The structure, curing behavior, and performance of the cured resin of the synthesized VTPN were characterized. The results suggest that the Schiff base may promote and participate in the crosslinking of nitrile, with a relatively high performance achieved under moderate curing conditions. This study provides a new green implementation scheme for high-performance polymers prepared through nucleophilic reactions, as well as for the high-performance and efficient utilization of widely existing bio-based aldehydes and amines. [Display omitted] • Bio-based phthalonitrile resin was synthesized in green solvent dimethylcarbonate. • Dimethylcarbonate was recovered and reused in the synthesis. • Imine unit was proved to promote the polymerization of phthalonitrile. [ABSTRACT FROM AUTHOR]
COPPER catalysts, ORGANIC chemistry, and PHARMACEUTICAL chemistry
Sulfondiimines, which contain a tetrasubstituted sulfur centre bearing two nitrogens and two carbon substituents, are a class of underexplored scaffolds in organic chemistry. Fascinated by some unique yet intriguing properties, sulfondiimines appear as leads in discovery industry, but the lack of efficient synthetic approaches holds back their further uptake by medicinal chemistry. Herein, a general and practical copper‐catalyzed Chan‐Lam coupling of NH‐diaryl sulfondiimines with arylboronic acids is presented. A simple copper catalyst efficiently facilitated the highly chemoselective construction of C−N bond, allowing the preparation of a variety of N‐arylated diaryl sulfondiimines in good yields under mild and environmentally benign conditions. An array of protecting groups on imine moieties were well tolerated, offering diversified accesses to NH,NAr‐diaryl sulfondiimines, a class of versatile building blocks. Moreover, an aza‐analogue of an EphB4 inhibitor featuring a sulfondiimine‐based pharmacophore was generated employing our Chan‐Lam coupling as the key step. [ABSTRACT FROM AUTHOR]
Feofanov, Mikhail, Sharapa, Dmitry I., and Akhmetov, Vladimir
Green Chemistry. 6/21/2022, Vol. 24 Issue 12, p4761-4765. 5p.
ORGANIC synthesis, ALKYNES, HYDROXYLATION, ALUMINUM oxide, and SUPERHEAVY elements
The discovery and development of new synthetic methods exploiting earth-abundant-element-based catalysts is an important goal in contemporary synthetic organic chemistry, which faces increasingly stringent requirements of sustainability. In this work, we disclose alumina-mediated propargylic C–H activation inducing a challenging transformation of readily available alkynes into a valuable 1,3-diene moiety under unprecedentedly mild conditions. Combining DFT-investigation and synthetic observations, we demonstrate that partial hydroxylation of alumina's surface might play an essential role in this process. [ABSTRACT FROM AUTHOR]
Green Chemistry. 6/21/2022, Vol. 24 Issue 12, p4952-4957. 6p.
ROSE bengal, KETONES, ALDEHYDES, ORGANIC chemistry, and AROMATIC aldehydes
Knoevenagel condensation is widely used in organic synthetic chemistry and several reaction conditions have been demonstrated. These reactions in neutral medium are challenging. In this report, we present a sustainable and greener method for Knoevenagel condensation reaction between carbonyl compounds (both aldehydes and ketones) and active methylene compounds using rose bengal as a photosensitizer in an aqueous medium. This protocol works smoothly for aromatic aldehydes and ketones containing both electron-donating and electron-withdrawing substituents. [ABSTRACT FROM AUTHOR]