Facile heterogenization of homogeneous ferrocene catalyst on SBA-15 and its hydroxylation activity

Ferrocene-based conjugated microporous polymer and its multiwalled carbon nanotube composite for direct photocatalytic benzene hydroxylation to phenol

Ferrocene is used as a catalytically active site and building block to construct a new conjugated microporous polymer (CMP), named Fc-POP. A corresponding carbon nanotube composite (CNTs@Fc-POP) with tubular structure was obtained through the π-π interaction between multi-walled carbon nanotubes (MWCNTs) and reactive molecules. This innovative modification method of carbon nanotubes provides a way to construct functionalized carbon materials. The two materials can achieve high conversion and selectivity of benzene hydroxylation to phenol under light irradiation using hydrogen peroxide (H2O2) as an oxidant. Due to the synergistic effect between the carbon nanotubes and the ferrocene group, the incorporation of MWCNTs can improve the yield of phenol significantly. This work explores a new photocatalystic system and expands the related photocatalytic application of CNTs.

Tuning the Synthesis of Manganese Oxides Nanoparticles for Efficient Oxidation of Benzyl Alcohol

The liquid phase oxidation of benzyl alcohol is an important reaction for generating benzaldehyde and benzoic acid that are largely required in the perfumery and pharmaceutical industries. The current production systems suffer from either low conversion or over oxidation. From the viewpoint of economy efficiency and environmental demand, we are aiming to develop new high-performance and cost-effective catalysts based on manganese oxides that can allow the green aerobic oxidation of benzyl alcohol under mild conditions. It was found that the composition of the precursors has significant influence on the structure formation and surface property of the manganese oxide nanoparticles. In addition, the crystallinity of the resulting manganese nanoparticles was gradually improved upon increasing the calcination temperature; however, the specific surface area decreased obviously due to pore structure damage at higher calcination temperature. The sample calcined at the optimal temperature of 600 °C from the precursors without porogen was a Mn3O4-rich material with a small amount of Mn2O3, which could generate a significant amount of [Formula: see text] species on the surface that contributed to the high catalytic activity in the oxidation. Adding porogen with precursors during the synthesis, the obtained catalysts were mainly Mn2O3 crystalline, which showed relatively low activity in the oxidation. All prepared samples showed high selectivity for benzaldehyde and benzoic acid. The obtained catalysts are comparable to the commercial OMS-2 catalyst. The synthesis-structure-catalysis interaction has been addressed, which will help for the design of new high-performance selective oxidation catalysts.

Ferrocenated nanocatalysts derived from the decomposition of ferrocenium in basic solution and their aerobic activities for the rapid decolorization of methylene blue and the facile oxidation of phenylboronic acid

A strategic preparation of ferrocenated compounds as aerobic catalysts was successfully carried out for the decolorization of methylene blue and oxidation of phenylboronic acid without light irradiation and excess addition of hydrogen peroxide.

Preparation of Pd/Fe3O4 nanoparticles by use of Euphorbia stracheyi Boiss root extract: A magnetically recoverable catalyst for one-pot reductive amination of aldehydes at room temperature

We describe a method for supporting palladium nanoparticles on magnetic nanoparticles using Euphorbia stracheyi Boiss root extract as the natural source of reducing and stabilizing agent. The progress of the reaction was monitored using UV-visible spectroscopy. The nanocatalyst was characterized by FE-SEM, TEM, XRD, EDS, FT-IR spectroscopy and ICP. The nanocatalyst was applied as an efficient, magnetically recoverable, highly reusable and heterogeneous catalyst for one-pot reductive amination of aldehydes at room temperature. The nanocatalyst was easily recovered by applying an external magnet and reused several times without considerable loss of activity.

Organocatalysis: Key Trends in Green Synthetic Chemistry, Challenges, Scope towards Heterogenization, and Importance from Research and Industrial Point of View

This paper purports to review catalysis, particularly the organocatalysis and its origin, key trends, challenges, examples, scope, and importance. The definition of organocatalyst corresponds to a low molecular weight organic molecule which in stoichiometric amounts catalyzes a chemical reaction. In this review, the use of the term heterogenized organocatalyst will be exclusively confined to a catalytic system containing an organic molecule immobilized onto some sort of support material and is responsible for accelerating a chemical reaction. Firstly, a brief description of the field is provided putting it in a green and sustainable perspective of chemistry. Next, research findings on the use of organocatalysts on various inorganic supports including nano(porous)materials, nanoparticles, silica, and zeolite/zeolitic materials are scrutinized in brief. Then future scope, research directions, and academic and industrial applications will be outlined. A succinct account will summarize some of the research and developments in the field. This review tries to bring many outstanding researches together and shows the vitality of the organocatalysis through several aspects.

Heterogeneous Metal Catalysts for Oxidation Reactions

Oxidation reactions may be considered as the heart of chemical synthesis. However, the indiscriminate uses of harsh and corrosive chemicals in this endeavor are threating to the ecosystems, public health, and terrestrial, aquatic, and aerial flora and fauna. Heterogeneous catalysts with various supports are brought to the spotlight because of their excellent capabilities to accelerate the rate of chemical reactions with low cost. They also minimize the use of chemicals in industries and thus are friendly and green to the environment. However, heterogeneous oxidation catalysis are not comprehensively presented in literature. In this short review, we clearly depicted the current state of catalytic oxidation reactions in chemical industries with specific emphasis on heterogeneous catalysts. We outlined here both the synthesis and applications of important oxidation catalysts. We believe it would serve as a reference guide for the selection of oxidation catalysts for both industries and academics.

Efficient photodegradation of Acid Red B by immobilized ferrocene in the presence of UVA and H2O2

SiO2-C2H4-ferrocene (SiCFe) was synthesized by covalent grafting of ferrocene on functionalized silica gel with a -C2H4- linkage. On the basis of characterization by diffuse reflectance UV-vis spectra (DRS) and Fourier transform infrared spectra (FT-IR), ferrocene has been successfully anchored on the silica gel. Under UVA (lambdamax=365 nm) irradiation, the catalyst exhibited high photocatalytic activity in the degradation of Acid Red B (ARB), especially in the presence of H2O2. Meanwhile, the catalytic activity of SiCFe was maintained effectively even after reused for 4 times without any significant destruction of ferrocene. The influence of initial solution pH and wavelength of UV light on the catalyst's activity was also investigated. Electron spin resonance (ESR) studies revealed that both OH and HO2/O2- radicals were involved as the active species in the ARB degradation process. Furthermore, results of total organic carbon (TOC) and FT-IR analysis indicated that ARB degradation proceeded by the cleavage of NN, followed by hydroxylation and opening of phenyl rings to form aliphatic acids and further oxidization of the aliphatic acids to produce carbon dioxide and water. A possible reaction mechanism was proposed on the basis of all the information obtained under various experimental conditions.