Fischer–Tropsch synthesis over CNT-supported cobalt catalyst: effect of magnetic field

In the present work, the cobalt catalysts supported on carbon nanotubes (CNTs) were prepared by impregnation method in the presence and absence of magnetic field. The prepared catalysts were employed to yield higher hydrocarbons via Fischer–Tropsch synthesis. It is explored that using magnetized water can effectively change the catalyst geometry in impregnation catalyst preparation method. For the preparation of different sizes of cobalt particles on the CNTs support, the physical properties of solvent (water) in impregnation process were changed using the magnetizing process. The results showed that the average particle sizes of impregnated cobalt nanoparticles were decreased by using magnetized water in impregnation step. In addition, in the magnetized treated cobalt catalyst, the cobalt particles mostly dispersed outside the tubes because the capillary forces decreased by reducing water surface tension. Furthermore, the experimental results showed that the probability of chain growth (α) and selectivity to heavier hydrocarbons increased in magnetized water treatment catalysts.     

Photodynamic Therapy with Zinc Phthalocyanine Inhibits the Stemness and Development of Colorectal Cancer: Time to Overcome the Challenging Barriers?

Photodynamic therapy (PDT) is a light-based cancer therapy approach that has shown promising results in treating various malignancies. Growing evidence indicates that cancer stem cells (CSCs) are implicated in tumor recurrence, metastasis, and cancer therapy resistance in colorectal cancer (CRC); thus, targeting these cells can ameliorate the prognosis of affected patients. Based on our bioinformatics results, SOX2 overexpression is significantly associated with inferior disease-specific survival and worsened the progression-free interval of CRC patients. Our results demonstrate that zinc phthalocyanine (ZnPc)-PDT with 12 J/cm² or 24 J/cm² irradiation can substantially decrease tumor migration via downregulating MMP9 and ROCK1 and inhibit the clonogenicity of SW480 cells via downregulating CD44 and SOX2. Despite inhibiting clonogenicity, ZnPc-PDT with 12 J/cm² irradiation fails to downregulate CD44 expression in SW480 cells. Our results indicate that ZnPc-PDT with 12 J/cm² or 24 J/cm² irradiation can substantially reduce the cell viability of SW480 cells and stimulate autophagy in the tumoral cells. Moreover, our results show that ZnPc-PDT with 12 J/cm² or 24 J/cm² irradiation can substantially arrest the cell cycle at the sub-G1 level, stimulate the intrinsic apoptosis pathway via upregulating caspase-3 and caspase-9 and downregulating Bcl-2. Indeed, our bioinformatics results show considerable interactions between the studied CSC-related genes with the studied migration- and apoptosis-related genes. Collectively, the current study highlights the potential role of ZnPc-PDT in inhibiting stemness and CRC development, which can ameliorate the prognosis of CRC patients.     

Magnetically recoverable lanthanum hydroxide as an efficient catalyst for Aerobic Oxidative Conversions of primary alcohols to the nitriles

Herein we report a novel magnetically recoverable lanthanum hydroxide nanoparticles for oxidative synthesis of nitriles directly from corresponding alcohols with ammonia as nitrogen source. The procedure for the preparation and characterization of La(OH)₃/Fe₃O₄ magnetic nanoparticles were investigated and the scope and generality of the method was explored for a series of structurally diverse primary alcohols with electron‐donating and electron‐withdrawing groups. The best result was observed when 5 mol% of La with respect to the benzyl alcohol was used at reflux condition under O₂ atmosphere. The La(OH)₃/Fe₃O₄ magnetic nanoparticles could be easily isolated from the reaction mixture with an external magnet and reused at least 5 times without significant loss in activity.     

New phosphonium molybdate-promoted green,fast and selective catalytic procedure for the synthesis of trisubstituted imidazoles

The compound 1,1′-(ethane,1,2-diyl)ditriphenylphosphonium hexamolybdate dimethylsulfoxide {C₂H₄[P(C₆H₅)₃]₂}{Mo₆O₁₉}·SO (CH₃)₂ ( I ) was prepared, and ¹H-NMR, ¹³C-NMR, Fourier transform-infrared, differential scanning calorimetry and single crystal X-ray diffraction analysis were used to characterize the titled compound. Crystallographic data showed that compound I crystallized in the monoclinic crystal system in C2/c space group. The compound ( I ) was used for selective synthesis of 2,4,5-tri aryl imidazole derivatives under solvent-free conditions efficiently. Because of hindrance of the catalyst, the yields of products for aldehydes bearing para substituents are higher than the aldehydes bearing ortho substituents, and for aromatic aldehydes with meta substituents are very low.     

Sample selection procedure in daily trading volume processes

In this paper, we propose a procedure of selecting samples from a set of samples coming from Markovian processes of finite order and finite alphabet. Under the assumption of the existence of a law that prevails in at least q% of the samples of the collection, we show that the procedure allows to identify samples governed by the predominant law. The approach is based on a local metric between samples, which tends to zero when we compare samples of identical law and tends to infinity when comparing samples with different laws. The local metric allows to define a criterion which takes arbitrarily large values when the previous assumption about the existence of a predominant law does not hold. By means of this procedure, we map similarities and dissimilarities of some Brazilian stocks' daily trading volume dynamic.     

Threonine stabilizer‐controlled well‐dispersed small palladium nanoparticles on modified magnetic nanocatalyst for Heck cross‐coupling process in water

We report the synthesis of magnetically separable Fe₃O₄@Silica‐Threonine‐Pd⁰ magnetic nanoparticles with a core–shell structure. After synthesis of Fe₃O₄@Silica, threonine as an efficient stabilizer/ligand was bonded to the surface of Fe₃O₄@Silica. Then, palladium nanoparticles were generated on the threonine‐modified catalyst. The threonine stabilizer helps to generate palladium nanoparticles of small size (less than 4 nm) with high dispersity and uniformity. Magnetically separable Fe₃O₄@Silica‐Threonine‐Pd⁰ nanocatalyst was fully characterized using various techniques. This nanocatalyst efficiently catalysed the Heck cross‐coupling reaction of a variety of substrates in water medium as a green, safe and inexpensive solvent at 80°C. The Fe₃O₄@Silica‐Threonine‐Pd⁰ catalyst was used for at least eight successful consecutive runs with palladium leaching of only 0.05%.     

Evaluation of the reaction mechanism for photocatalytic degradation of organic pollutants with MIL-88A/BiOI structure under visible light irradiation

Research on Chemical Intermediates - In this study, we synthesized novel visible light photocatalyst MIL-88A/BiOI using depositing BiOI particles on the surface of a metal–organic framework...     

Uniformly dispersed copper nanoparticles onto the modified magnetically recoverable nanocatalyst for aqueous synthesis of primary amides

Magnetically recoverable and environmentally friendly Cu‐based heterogeneous catalyst has been synthesized for the one‐pot conversion of aldehydes to their corresponding primary amides. The Fe₃O₄@SiO₂ nanocomposites were prepared by synthesis of Fe₃O₄ magnetic nanoparticles (MNPs) which was then coated with a silica shell via Stöber method. Bi‐functional cysteine amino acid was covalently bonded onto the siliceous shell of nanocatalyst. The Cu^II ions were then loaded onto the modified surface of nanocatalyst. Finally, uniformly dispersed copper nanoparticles were achieved by reduction of Cu^II ions with NaBH₄. Amidation reaction of aryl halides with electron‐withdrawing or electron‐donating groups and hydroxylamine hydrochloride catalyzed with Fe₃O₄@SiO₂@Cysteine‐copper (FSC‐Cu) MNPs in aqueous condition gave an excellent yield of products. The FSC‐Cu MNPs could be easily isolated from the reaction mixture with an external magnet and reused at least 8 times without significant loss in activity.     

Using magnetized water as a solvent for a green,catalyst-free,and efficient protocol for the synthesis of pyrano[2,3-c]pyrazoles and pyrano[4′,3′:5,6]pyrazolo [2,3-d]pyrimidines

Research on Chemical Intermediates - A facile, eco-friendly, and highly efficient one-pot four-component protocol is demonstrated for the synthesis of the pyrano[2,3-c]pyrazole and...     

Efficient 2,4,6‐trichloro‐1,3,5‐triazine‐catalyzed synthesis of 2‐arylbenzothiazoles and bisbenzothiazoles by condensation of 2‐aminithiophenol with aldehydes under mild conditions

2,4,6‐Trichloro‐1,3,5‐triazine efficiently catalyzed the condensation reactions between 2‐aminothiophenol and aromatic aldehydes to afford 2‐arylbenzothiazolles in good‐to‐excellent yields. Simple and mild reaction conditions, the use of a cheap catalyst and easy work up, and isolation are notable features of this method. J. Heterocyclic Chem., (2011).