Solid State Synthesis of Hematite Nanoparticles from Doped Poly o-aminophenol (POAP)

Recyclable magnetically retrievable nanocatalysts for C–heteroatom bond formation reactions

During recent years, magnetic separation has proven to be a highly indispensable and sustainable tool for facile separation of catalysts from the reaction medium with the aid of only an external magnetic force that precludes the requirement of energy intensive, solvent based centrifugation or filtration techniques. Extensive research in the area of catalysis has clearly divulged that while designing any catalyst, the foremost features that need to be paid due attention to include high activity, ready recoverability and good reusability. Fortunately, the magnetic nanocatalysts involving a superparamagnetic core material that could comprise of iron oxides such as magnetite, maghemite or hematite or mixed ferrites (CoFe2O4, CuFe2O4) have offered bright prospects of designing the ideal catalysts by proving their efficacy as strong support material that could be further engineered with various tools of nanotechnology and efficiently catalyze various C–heterobond formation reactions. This chapter provides succinct overview of all the approaches utilized for fabricating different types of magnetic nanoparticles and strategies adopted for imparting them durability. The prime forte however remains to exclusively showcase the applications of the various types of magnetic nanocatalysts in C–O, C–N, C–S and miscellaneous (C–Se, C–Te) bond formation reactions which are anticipated to benefit the synthetic community on a broad spectrum by helping them rationalize and analyze the key features that need to be taken into account, while developing these magical nanostructured catalytic systems for boosting the green bond formation reactions/transformations.

A Surface Plasmon Resonance-Based Optical Fiber Probe Fabricated with Electropolymerized Molecular Imprinting Film for Melamine Detection

Molecularly imprinted polymer (MIP) films prepared by bulk polymerization suffer from numerous deficiencies, including poor mass transfer ability and difficulty in controlling reaction rate and film thickness, which usually result in poor repeatability. However, polymer film synthesized by electropolymerization methods benefit from high reproducibility, simplicity and rapidity of preparation. In the present study, an Au film served as the refractive index-sensitive metal film to couple with the light leaked out from optical fiber core and the electrode for electropolymerizing MIP film simultaneously. The manufactured probe exhibited satisfactory sensitivity and specificity. Furthermore, the surface morphology and functional groups of the synthesized MIP film were characterized by Atomic Force Microscopy (AFM) and Fourier transform infrared microspectroscopy (FTIR) for further insights into the adsorption and desorption processes. Given the low cost, label-free test, simple preparation process and fast response, this method has a potential application to monitor substances in complicated real samples for out-of-lab test in the future.

Novel and economic acid-base indicator based on (p-toluidine) oligomer: Synthesis; characterization and solvatochromism applications

A new (p-toluidine) oligomer (PTO) was facile synthesized and economically routed via chemical oxidative polymerization by potassium dichromate as an initiator in an acidic aqueous medium at room temperature. The characterization of (p-toluidine) oligomer (PTO) has been described by various techniques including Fourier transform infra-red (FTIR), UV-Visible measurements, Mass spectra, H NMR, and thermal gravimetric analysis (TGA). Solvatochromism of PTO was studied in different polaritiy solvents such as acetic acid, acetone, dimethyl formamide, ethanol, isopropanol, chloroform, p-xylene, dichloromethane and carbon teterachloride. The absorption bands were bathochromically shifted with increased polarity of the solvent (positive solvatochromism). PTO shows three isosbestic points at 333, 388 and 472nm in a binary mixture of acetone and chloroform. The deprotonation constants of PTO were found to be 3.1 and 5.8, based on spectrophotometric calculations. PTO was successfully used as an acid-base indicator; the acid solution color sharply turned from pink (acidic medium) to yellow (basic medium) at the end point.