Microporous aluminophosphate (AlPO-5) and titanium aluminophosphate (TAPO-5) molecular sieves, which are zeolite-like materials have been synthesized by direct hydrothermal method using two different templates; triethylamine (TEA) as organic base and tetraethylammonium hydroxide (TEAOH) as alkali base. XRD patterns confirmed that the TAPO-5 catalysts are identical with AFI structure but the crystallinity of the catalysts had decreased after the incorporation of titanium into the framework. Besides that, characterization of TAPO-5 catalysts using DRUV-Vis confirmed the coordination of titanium species and this evidenced also supported by the result 27Al MAS NMR. Catalytic performance of the TAPO-5 catalysts was tested in the oxidation of styrene to produce benzaldehyde and phenylacetaldehyde in the presence of hydrogen peroxide as oxidant. TAPO-5 catalysts showed higher activity in styrene oxidation compared to AlPO-5. Keywords: zeolite; aluminophosphate; titanium; organic template; styrene
N’-(5-nitro-2-oxoindolin-3-ylidene) thiophene-2-carbohydrazide (NH) was successfully synthesized as a ligand, then grafted onto the surface of mesoporous silica SBA-15via an aminopropyl bridge. The successful grafting of ligand NH onto the hybrid nanomaterial (SBA-15/APTES-NH) was confirmed by infrared spectroscopy. On excitation at 276 and 370 nm, the ligand NH and the hybrid nanomaterial SBA-15/APTES-NH showed a strong and narrow emission peak centered at 533 nm. By dispersing SBA-15/APTES-NH in an aqueous solution containing metal ions, the resulting solid materials showed a higher binding of NH sensing site to Fe3+ ions as compared to the others with a quench of the emission intensity up to 84%. This result showed that the hybrid nanomaterial is a potential chemosensor that requires development for the detection of metal ions.
Synthetic metalloporphyrins have long been recognized either as functional models or mimics of the cytochrome P-450 enzymes and they are versatile compounds with potential use in drug delivery, catalysis and electronics. In the present study, the metalloporphyrin, (meso-tetra-(p-sulfonatophenyl)-porphyrinato)copper, CuTSPP was synthesized in the reaction between free-base porphyrin, meso-tetra (p-sulfonatophenyl)porphyrin, H2TSPP and copper(II) acetate monohydrate. The materials were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible (UV-Vis) Spectroscopy, Proton Nuclear Magnetic Resonance (1H NMR) Spectroscopyand Mass Spectrometry (MS) analysis. The FTIR spectra of both free-base porphyrin and CuTSPP showed the appearance of three pronounced bands indicating the presence of the salt form (R-SO3Na) of the sulfonic acid group. Characterization of CuTSPP by UV-Vis spectroscopy confirmed that the insertion of copper into the free-base porphyrin was successful by the appearance of the Soret band and Q bands. The catalytic activity of CuTSPP was tested in the oxidation of 2,3,6-trimethylphenol (TMP) at 60 °C using hydrogen peroxide (H2O2) as oxidant. The reaction parameters including the reaction temperature and time have been optimized. The only product obtained by means of TMP oxidation with H2O2 using CuTSSP is 2,3,5-trimethylbenzoquinone (TMBQ), an important precursor for the industrial production of Vitamin E.
SBA-15 nanoporous silica was prepared by cooperative self-assembly of tetraethylorthosilicate precursor in the presence of poly(ethylene glycol)–block–poly(propylene glycol)–block–poly(ethylene glycol) copolymer surfactant and functionalized with (3-aminopropyl) triethoxysilane (APTES) via sol-gel reaction to obtain NH2-SBA-15. The metalloporphyrin, [meso-tetrakis-(p-chlorophenyl)porphyrinato]Zn(II) (ZnTClPP) was synthesized from the reaction of meso-tetrakis-(p-chlorophenyl) porphyrin (H2TClPP) using zinc acetate dihydrate as a metal source and then immobilized on SBA-15 surface. The material, NH2-SBA-15-ZnP was characterized by SAXS, FESEM and BET studies and showed a similar pattern as SBA-15 indicating that the mesoporous hexagonal structure of SBA-15 was still retained. Then, the material was applied to catalyze the epoxidation of limonene, using H2O2 / ammonium acetate at various temperatures and conditions. All the products formed from the epoxidation reaction were analyzed using GC-FID and GC-MS.
Rare earth elements (REEs) are the elements that have become extremely important to our world of technology owing to their unique physical and chemical properties, and widely used in advanced technology. Monazite is one of the mineral phosphate that contain a high amount of REEs including thorium and a small amount of uranium. In Malaysia, monazite is exist as by-product (‘amang’) from tin mining originated from Ipoh, Perak. The objective of this study is to determine the effects of the different particles size of raw and ground (milled) monazite on the physicochemical properties. The effectiveness of extraction and separation process of monazite was affected by the size of the particle. Based on the particle size distribution analysis, all the monazite samples were found to be present in the size range of 11-190 μm. The morphological and elemental composition of the monazite mineral have been characterized by field emission scanning electron microscope (FESEM) integrated with energy dispersive X-ray spectrometer (EDX). The FESEM micrographs of the monazite showed an irregular spherical structures with different sizes. The chemical composition and the mineral phases present in monazite were studied by wavelength-dispersive X-ray fluorescence spectrometer (WD-XRF) and X-ray diffraction (XRD). The XRF analysis confirmed the presence of the major REEs such as Ce, La and Nd elements in the mineral. XRD analysis also identified (Ce, La, Nd and Th)PO4 as the major phases along with quartz as minor phase. According to the FESEM-EDX and XRF analysis, smaller particle size of monazite gave higher content of REEs compare to raw monazite.
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