Pores Of zeolite-Y Research Articles

Synthesis and characterization of NaY zeolite-encapsulated Mn-hydrazone Schiff base: an efficient and reusable catalyst for oxidation of olefins

The Mn-hydrazone Schiff base has been prepared, characterized, and encapsulated into NaY to prepare a new heterogeneous catalyst. Elemental analysis, UV-Vis, infrared spectroscopic analysis, diffuse reflectance spectroscopy, thermal analysis, small angle X-ray diffraction, and N2 sorption indicate the presence of Mn-hydrazone Schiff base within the nanocavity pores of zeolite-Y. The catalysts showed excellent catalytic efficiency in epoxidation with various olefinic compounds including cyclooctene, using tert-BuOOH as oxidant. Cyclooctene showed high conversion (97%) as well as epoxide selectivity (89%) with tert-BuOOH. Moreover, the encapsulated complex showed good recoverability without significant loss of activity and selectivity within successive runs.

Template synthesis and characterization of diaza dioxa macrocyclic nanosized cobalt(II) complex dispersed within nanocavity of zeolite-Y

Nanocavity microreactor containing 15- and 16-membered diaza dioxa Schiff-base cobalt(II) complexes “[Co(Et[15]N 2O 2)] 2+, [Co(Pr[16]N 2O 2)] 2+, [Co(Ph[15]N 2O 2)] 2+ and [Co(Ch[15]N 2O 2)] 2+” have been prepared by the template synthesis of diamine (1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene or 1,2-diaminocyclohexane) with [(1,3-bis(2-carboxyaldehydephenoxy)propane)cobalt] 2+;[Co(BCAPP)] 2+@NaY within the pores of zeolite-Y. The nanosized cobalt(II) complex were entrapped in the supercage of Y-zeolite by a three-step process in the liquid phase: (i) exchange of Co(II) ions with NaY in water solution, (ii) reaction of Co(II)–NaY with excess BCAPP in methanol; [Co(BCAPP)] 2+@NaY; (iii) template synthesis of [Co(BCAPP)] 2+@NaY with diamine. The new nanosized complex entrapped in the nanocavity of zeolite Y was characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV–Vis, XRD, BET, DRS, XPS, TGA).

Hydrogen adsorption in organic ion-exchanged zeolites

As the promising alternative to improve the hydrogen storage capacity, four types of organic ion-exchanged zeolite-Y (OZ) were synthesized and the hydrogen storage capacities were measured. By introducing the organic ions in the pores of zeolite-Y, the hydrogen uptake was increased to a measurable extent. OZ demonstrates impressive hydrogen storage capacity of 0.15–0.34 wt% at 298 K and 10 MPa, where the Na-Y zeolite has been reported to have no efficiencies. In this study, two organic molecules, pyridine hydrochloride and pyridinium chlorochromate, are tried to identify its unique role in hydrogen uptake. The effect of light ion exchange for the synthesis of OZ on the hydrogen uptake is also given. From these results, we could identify that OZ can be designed and synthesized for the efficient hydrogen storage materials.

Host (nanocavity of zeolite-Y)/guest (Mn(II), Co(II), Ni(II) and Cu(II) complexes of pentadendate Schiff-base ligand) nanocomposite materials (HGNM): application in the heterogeneous oxidation of cyclohexene

Transition metal (M = Mn(II), Co(II), Ni(II) and Cu(II)) complexes with pentadendate Schiff-base ligand; N,N′-bis(salicylidene)-2,6-pyridinediaminato, H2 [sal-2,6-py]; was entrapped in the nanocavity of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of bis(salicylaldiminato)metal(II); [M(sal)2]-NaY; in the supercages of the zeolite, and (ii) in situ Schiff condensation of the metal(II) precursor complex with the corresponding 2,6-pyridinediamine; [M(sal-2,6-py)]-NaY. The new materials were characterised by several techniques: chemical analysis, spectroscopic methods (DRS, BET, FTIR and UV/Vis), conductometric and magnetic measurements. Analysis of the data indicates that the M(II) complexes are encapsulated in the nanodimensional pores of zeolite-Y and exhibit different from those of the free complexes, which can arise from distortions caused by steric effects due to the presence of sodium cations, or from interactions with the zeolite matrix. The Host–Guest Nanocomposite Materials (HGNM); [M(sal-2,6-py)]-NaY; catalyzes the oxidation of cyclohexene with tert-butylhydroperoxide (TBHP). Oxidation of cyclohexene with HGNM gave 2-cyclohexene-1-one, 2-cyclohexene-1-ol and 1-(tert-butylperoxy)-2-cyclohexene. [Mn(sal-2,6-py)]-NaY shows significantly higher catalytic activity than other catalysts.

Synthesis, characterization and liquid phase oxidation of cyclohexanol using tert-butylhydroperoxide over host (zeolite-Y)/guest (copper(II) complexes of 12- and 13-membered diaza dioxa Schiff-base macrocyclic ligand) nanocomposite materials (HGNM)

Nanocavity microreactor containing 12- and 13-membered diaza dioxa Schiff-base copper(II) complexes have been prepared by the one-pot template synthesis of (1,8-diamino-3,6-dioxaoctane)copper(II) with bifunctional diketone within the pores of zeolite-Y. The copper(II) complexes were entrapped in the supercage of Y-zeolite by a two-step process in the liquid phase: (i) inclusion of a copper(II) precursor complex, [Cu(1,8-diamino-3,6-dioxaoctane)] 2+-NaY and (ii) template condensation of the copper(II) precursor complex with the bifunctional diketone. Encapsulated copper(II) complex is catalytically very efficient as compared to other neat complexes for oxidation of cyclohexanol with tert-butylhydroperoxide (TBHP) as oxidant and is stable to be recycled without much deterioration.

NO trapping in biological systems with a functionalized zeolite network

Zeolite-Y powder has been functionalized with ferric iron-diethyldithiocarbamate complexes and applied to trap nitric oxide radicals in liquids and biological systems. The complexes have been assembled in situ in the pores of zeolite-Y and act as traps for nitric oxide radicals. The resulting mononitrosyl-iron complexes form a mixture of diamagnetic ferric and paramagnetic ferrous complexes. The yield of trapped NO may be determined ex situ using electron paramagnetic resonance. The material may be anchored on solid surfaces, mixed into a composite or compressed into small pellets. The material was used to detect endogenous NO in endothelial cell cultures and spinach leaves. The sensitivity of the functionalized zeolite is significantly better than that achieved in conventional trapping of NO with iron-diethyldithiocarbamate complexes.

Synthesis, characterization and catalytic activity of copper(II) complexes of 14-membered macrocyclic ligand; 3,10-dialkyl-dibenzo-1,3,5,8,10,12-hexaazacyclotetradecanel/zeolite encapsulated nanocomposite materials

Nanodimensional microreactor containing (3,10-dialkyl-dibenzo-1,3,5,8,10,12-hexaazacyclotetradecane)copper(II) complexes have been prepared by the one-pot template synthesis of formaldehyde and 1,2-phenylenediamine (1,2-phen) with alkyl and benzyl amine within the pores of zeolite-Y. The copper(II) complexes were entrapped in the supercage of Y-zeolite by a two-step process in the liquid phase: (i) inclusion of a copper(II) precursor complex, [Cu(1,2-phen) 2] 2+-NaY, and (ii) template condensation of the copper(II) precursor complex with the formaldehyde and amine. The spectra of the neat and encapsulated complexes show that the four secondary nitrogen atoms are coordinated to the copper(II) ion. Encapsulated copper(II) complex is catalytically very efficient as compared to other neat complexes for the partial oxidation of benzyl alcohol with hydrogen peroxide as oxidant and is stable to be recycled without much deterioration.