Catalytic and electrocatalytic properties of intrazeolitically prepared iron phthalocyanine

Iron-phthalocyanine (FePc) has been successfully synthesised inside the pores of the NaY zeolite as evidenced by various physicochemical characterisation methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD), electron spin resonance spectroscopy (ESR), ultraviolet spectroscopy (UV), cyclic voltammetry (CV) and thermal methods of analysis. XRD analysis indicates the formation of FePc molecules inside the supercages. SEM pictures show that the original microporous nature of NaY is not affected by encapsulation of FePc. ESR spectrum shows two peaks with g values of 1.977 and 4.030 indicating the partial oxidation of FePc in the cavity, while IR spectra suggest that the molecule can undergo a saddle deformation inside the zeolite matrix. In UV-Vis spectrum, the Q band of the FePc molecule is shifted from 656 nm to 686 nm, although the soret band is less affected. Thermal analysis indicates that these molecules have enhanced thermal stability inside the zeolite cavities. Cyclic voltammetric studies show that the electrochemical behaviour of pure FePc is not much affected by the encapsulation. The encapsulated FePc molecules are found to catalyse the hydrocarbon oxidation reactions. In addition, modified electrodes prepared with this material indicate good electrocatalytic effects as demonstrated by a 260 mV shift in the peak potential for oxygen reduction in neutral medium. Considerable electrocatalytic behaviour is also observed for oxidation of hydrazine

Aromatization of n-hexane over platinum alkaline ETS-10

The performance of Pt impregnated alkali metal exchanged ETS-10 as a bifunctional catalyst for the reforming of n-hexane has been examined in the temperature range of 673K to 773K at atmospheric pressure. A comparison of the activity of the above catalysts at the same conditions with Pt-Al2O3 has also been carried out. Pt-(alkaline)-ETS-10 samples exhibit greater aromatization activities than the Pt-Al2O3

Studies on the synthesis of ETS-10 II. Use of organic templates

ETS-10 has been synthesized using titanosilicate gels and organic templating agents such as choline chloride [OHCH2CH2(CH3)3N+Cl−] and the bromide salt of hexaethyl diquat-5 [Br−(C2H5)3N+(CH2)5N+(C2H5)3Br−]. The influences of temperature and concentration of the ingredients on the kinetics of synthesis are reported. Physicochemical characterizations of the samples have been carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and differential thermogravimetric analysis (DTA)/thermogravimetric analysis (TGA), and adsorption of water, n-hexane and mesitylene. The catalytic activities of H-ETS-10 in the dehydration of n-butanol and in the isomerization of m-xylene and 1,3,5-trimethylbenzene are reported

Cu<SUP>2+</SUP>-perchlorophthalocyanine immobilized MCM-41: catalyst for oxidation of alkenes

The immobilization of copperperchlorophthalocyanine (CuCl<SUB>16</SUB>Pc) complex in the channels of HSi-MCM-41 molecular sieves has been carried out by (i) post-synthesis in the presence of 3-aminopropyltriethoxysilane (3-APTES) and (ii) impregnation in the absence of 3-APTES. The resulting host-guest samples were characterized by XRD, MAS-NMR, nitrogen adsorption, IR and cyclic voltammetry. Each sample showed an IR band at 1390 cm<SUP>&#8722;1</SUP> suggesting the presence of CuCl<SUB>16</SUB>Pc complex in the channels of HSi-MCM-41. The results of the alkene epoxidation in presence of (i) TBHP and (ii) O<SUB>2</SUB>/isobutyraldehyde are compared. The oxo-metal and acyl peroxy radical species that formed predominantly using isobutyraldehyde give a high yield of epoxide, as compared to the reaction using TBHP as the oxidant

A rapid method of synthesizing the titanium silicate ETS-10

The use of TiCl<SUB>4</SUB> as the source of Ti produces highly crystalline and pure ETS-10 samples within 16 h

Studies on the synthesis, characterization and catalytic properties of the large pore titanosilicate, ETS-10

The titanosilicate ETS-10 has been synthesized from titanosilicate gels in the presence and absence of seeds of ETS-4 and in the presence of an organic templating agent. The templates used were choline chloride [HOCH2CH2(CH3)3N+Cl−] and the bromide salt of hexaethyl diquat-5 [Br−(C2H5)3N+(CH2)5N+(C2H5)3Br−]. The influence of some synthesis parameters on the crystallization of ETS-10 in the presence and absence of seeds and templates has been investigated. The physico-chemical characterization of these synthesized materials has been carried out by XRD, SEM, IR, DTA/TGA and sorption of different probe molecules. The activities of the H-forms of the ETS-10 samples prepared by the different routes in catalyzing the dehydration of n-butanol, isomerization of m-xylene and 1,3,5-trimethyl benzene are reported

Beckmann rearrangement of cyclohexanone oxime over mesoporous Si-MCM-41 and Al-MCM-41 molecular sieves

Si-MCM-41 and Al-MCM-41 with different Al contents (Si/Al=43.9, 23.3 and 14.3) have been prepared using cetyl trimethylammonium bromide as an organic surfactant and characterised by XRD, MAS NMR and N2 sorption studies. The transformation of cyclohexanone oxime into &#949;-caprolactam has been studied over these molecular sieves. The influences of temperature and feed rate (WHSV) on the yield of caprolactam over the samples have been investigated at different times on stream. The studies reveal that activity and selectivity increase with Al content (investigated upto Si/Al=14) and maximum yield of &#949;-caprolactam is obtained at ~360 &#176;C

Synthesis of silver nanowires inside mesoporous MCM-41 host

Silver nanowires were prepared using template method inside the channels of MCM-41 by controlled reduction of AgNO3 with sodium borohydrate (NaBH4). Advantage of template method is that it provides good control over size and shape of the nanowires and nanomaterial with desired aspect ratio can be prepared. Silver nanowire formation inside the channels of MCM-41 is confirmed by TEM, which shows silver nanowires with diameter ~ 2.8 nm coincident with channel diameter of MCM-41. XRD pattern also shows presence of silver. Studies of optical properties of this heterostructure material Ag/MCM-41 reveals the presence of surface plasmon absorption peak of silver, which is red shifted compared with that of silver nanoparticles due to agglomeration of silver clusters inside the channels. Room temperature photoluminescence spectra exhibits interesting optical properties as observed for direct-band gap semiconductors

Studies on the synthesis of ETS-10 I. Influence of synthesis parameters and seed content

The influence of various parameters such as temperature, concentration of the ingredients and amount of seed used on the kinetics of the synthesis of the large-pore molecular sieve ETS-10 is reported in the paper. Detailed physicochemical characterizations of the samples have been carried out with instrumental techniques such as X-ray diffraction (XRD), scanning-electron microscopy (SEM), ultraviolet-visible (UV-VIS) spectroscopy, infrared (IR) spectroscopy nuclear magnetic resonance (NMR) and sorption of water, n-hexane and mesitylene