Covalently Anchored Polymer Immobilized Co(II) Phthalocyanine as Efficient Catalyst for Oxidation of Mercaptans using Molecular Oxygen as Oxidant

Management of methyl mercaptan contained in waste gases - an overview

Methyl mercaptan is a typical volatile organosulfur pollutant contained in many gases emitted by urban waste treatment, various industries, natural gas handling, refining processes, and energy production. This work is a comprehensive overview of the scientific and practical aspects related to the management of methyl mercaptan pollution. The main techniques, including absorption, adsorption, oxidation, and biological treatments, are examined in detail. For each method, its capability as well as the technical advantages and drawbacks have been highlighted. The emerging methods developed for the removal of methyl mercaptan from natural gas are also reviewed. These methods are based on the catalytic conversion of CH3SH to hydrocarbons and H2S.

A light-facilitated drug delivery system from a pseudo-protein/hyaluronic acid nanocomplex with improved anti-tumor effects

Reduction-sensitive nanomedicine is a promising strategy to achieve controlled release of payloads in response to intracellular reductive milieu. However, endolysosomal sequestration of internalized carriers and insufficient redox potential in endolysosomes may delay the release of payloads and impact their therapeutic efficacy. Photochemical internalization (PCI), which takes advantage of light-induced endolysosomal rupture, is an effective technique for endosomal escape and cytosolic release of cargos. In this study, a biodegradable and reduction-sensitive nanocomplex was developed from arginine based poly(ester amide)s and hyaluronic acid (HA), and the PCI-photosensitizer AlPcS2a was conjugated to the surface of the nanocomplex (ArgPEA-ss-HA(AP)). This nanocomplex was used for the co-delivery of both PCI-photosensitizers and therapeutic agents to eliminate the biodistribution discrepancy resulting from the separated administration of free therapeutics. The PCI effect of the ArgPEA-ss-HA(AP) nanocomplex was validated in both monolayers and 3D spheroid models of MDA-MB-231 breast cancer cells. Synergism was detected between the PCI effect and doxorubicin-loaded nanocomplex in the inhibition of MDA-MB-231 cells. In addition, the ArgPEA-ss-HA(AP) nanocomplex also provided enhanced intratumoral penetration in 3D spheroids compared to free AlPcS2a. The in vivo results suggested that the conjugation of AlPCs2a in the nanocomplex enabled the consistent and preferential accumulation of both doxorubicin and AlPcS2a in tumor sites. A light-enhanced anti-tumor effect was observed for the doxorubicin-loaded nanocomplex at well-tolerable dosage. The ArgPEA-ss-HA(AP) nanocomplex, as a reduction-responsive delivery vehicle, can hold great potential to achieve spatio-temporally controllable anti-tumor effects.

Theoretical Studies of the Zeolite-Y Encapsulated Chlorine-Substituted Copper(II)phthalocyanine Complex on the Formation Glycidol from Allyl Alcohol

Density functional theory (DFT) used to study the encapsulation of copper(II)phthalocyanine and chlorine-substituted copper(II)phthalocyanine to a zeolite-Y framework. Changes occurring in the redox properties, as well as the red shift of the time-dependent DFT (TD-DFT) spectra, point out the influence of encapsulation on the geometric parameters of the complexes. Also, the TD-DFT calculations show good agreement with the energy changes occurred in the highest occupied molecular orbital and lowest unoccupied molecular orbital. DFT-based descriptors are used for scrutinizing the reactivity of the encapsulated complexes and a mechanism of the glycidol formation is proposed based on the energetics involved in the transformation.

Synthesis and characterization of graphene oxide supported cobalt (II) tetrasulfophthalocyanine as an efficient heterogeneous nanocatalyst for mercaptans oxidation from gasoline

In the present study, graphene oxide-supported cobalt (II) tetrasulfophthalocyanine (CoTsPc-GO) was synthesized using the incipient wetness impregnation assisted [Formula: see text]–[Formula: see text] assembling method. Applications for this material were investigated for ethyl mercaptan, [Formula: see text]-propyl mercaptan and [Formula: see text]-butyl mercaptan oxidation from fluid catalytic cracking (FCC) gasoline in a fixed bed reactor. The synthesized CoTsPc-GO catalysts were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy analysis, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDAX), thermogravimetric and differential thermal analysis (TGA-DTA), inductively coupled plasma optical emission spectroscopy (ICP-OES), and transmission electron microscopy (TEM). The effect of cobalt (II) tetrasulfophthalocyanine (CoTsPc) content (0–0.34 g), catalyst dosage (0.02–0.12 g) and temperature (30–40∘ C) on the performance of CoTsPc-GO catalysts were investigated during the Merox process. The stability and reusability of CoTsPc-GO catalyst for mercaptans oxidation were also tested. The obtained results revealed that the maximum mercaptan oxidation during the Merox process was obtained in CoTsPc-GO of 0.34 g, catalyst content of 0.1 g and a temperature of 40∘ C with ethyl mercaptan, [Formula: see text]-propyl mercaptan and [Formula: see text]-butyl mercaptan conversions of 99.9, 98.5 and 97.0%, respectively. The potential of CoTsPc-GO catalyst was investigated for further mercaptans oxidation. The results were compared to those obtained with an industrial impregnated active charcoal catalyst and a CoPc catalyst. The obtained results demonstrated the higher capability of CoTsPc-GO catalyst for mercaptans oxidation from FCC gasoline.

Iron phthalocyanine supported on amidoximated PAN fiber as effective catalyst for controllable hydrogen peroxide activation in oxidizing organic dyes

Iron(II) phthalocyanine was immobilized onto amidoximated polyacrylonitrile fiber to construct a bioinspired catalytic system for oxidizing organic dyes by H₂O₂ activation. The amidoxime groups greatly helped to anchor Iron(II) phthalocyanine molecules onto the fiber through coordination interaction, which has been confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy analyses. Electron spin resonance studies indicate that the catalytic process of physically anchored Iron(II) phthalocyanine performed via a hydroxyl radical pathway, while the catalyst bonded Iron(II) phthalocyanine through coordination effect could selectively catalyze the H₂O₂ decomposition to generate high-valent iron-oxo species. This may result from the amidoxime groups functioning as the axial fifth ligands to favor the heterolytic cleavage of the peroxide OO bond. This feature also enables the catalyst to only degrade the dyes adjacent to the catalytic active centers and enhances the efficient utilization of H₂O₂. In addition, this catalyst could effectively catalyze the mineralization of organic dyes and can be easily recycled without any loss of activity.

Sulfonated Co(II) phthalocyanines covalently anchored at organic polymers as catalyst for mild oxidation of mercaptans

Current work is devoted to covalent immobilization of sulfonated derivatives of cobalt phthalocyanines “Merox catalysts” on the surfaces of polypropylene and polyethylene terephthalate. Their catalytic activity in reaction of mild oxidation of sulfur compounds to disulfides with oxygen of the air was studied. Anchoring of the catalyst on this polymer prevents its leaching and promotes its efficient recovering and recycling without significant loss of catalytic activity.

A two in one approach: renewable support and enhanced catalysis for sweetening using chicken feather bound cobalt(ii) phthalocyanine under alkali free environment

Poultry waste chicken feathers, an inexpensive and abundantly available material has been used as a renewable support for immobilizing a cobalt phthalocyanine catalyst.

Photo-assisted oxidation of thiols to disulfides using cobalt “Nanorust” under visible light

A pyrolyzed cobalt based heterogeneous catalyst was found to be a more effective catalyst than the heterogenized CoPc@CeO₂ for oxidation of thiols to disulfides under visible light.

Photoelectrode characteristics of partially hydrolyzed aluminum phthalocyanine chloride/fullerene C₆₀ composite nanoparticles working in a water phase

Photoelectrochemical measurements were used to study the photoelectrode characteristics of composite nanoparticles composed of fullerene C₆₀ and partially hydrolyzed aluminum phthalocyanine chloride (AlPc). In cyclic voltammetry measurements, the electrodes coated with the composite nanoparticles were found to have photoanodic [electron donor: 2-mercaptoethanol (ME)] and photocathodic (electron acceptor: O₂) characteristics similar to those of the vapor-deposited p/n junction electrode. Their photoanodic features were further investigated with respect to the transient photocurrent response to light irradiation and the dependence on ME concentration (under potentiostatic conditions), from which it was noted that there was a decrease in the initial spiky photocathodic current and saturation of the steady-state photoanodic current at a higher ME concentration. Thus, the reaction kinetics was probably dominated by charge transport process. Moreover, external and internal quantum efficiency spectrum measurements indicated that the composite nanoparticles responded to the full spectrum of visible light (<880 nm) for both the photoanodic and photocathodic current. The present research will assist comprehension of photocatalytic behavior of the composite nanoparticles.