Zinc titanate nanopowder: an advanced nanotechnology based recyclable heterogeneous catalyst for the one-pot selective synthesis of self-aggregated low-molecular mass acceptor―donor―acceptor―acceptor systems and acceptor―donor―acceptor triads

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 14; no. 5; pp. 1376 - 1387
• Main Authors: DAS, Paramita, BUTCHER, Ray J, MUKHOPADHYAY, Chhanda
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2012
• Subjects: Catalysis; Catalysts: preparations and properties; Chemistry; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Water; One pot reaction; Nanoparticle; Toxicity; Scale effect; Photoluminescence; Selectivity; Zinc Oxides; High temperature; Powder; Characterization; Metal oxides; Raman spectrometry; Nanopowder; Recycling; Chemical synthesis; Acid medium; Lewis acid; Scanning electron microscopy; Catalytic reaction; Titanium IV; Multicomponent reaction; Aldehyde; Ketone; X ray diffraction; High pressure; Titanium Oxides; Heterogeneous catalysis; Hydrogen cyanides; Extrapolation; Ultraviolet radiation; Sol gel process; Preparation; Laser; Green chemistry; Large scale; Triad; Catalyst; Nanotechnology; Zinc Titanates
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/c2gc16641k

Highly stable, environmentally benign ZnTiO sub(3) nanopowder has been prepared viaa sustainable sol-gel method. The nanopowder (90 nm) has been thoroughly characterized by SEM, XRD, EDS, Laser Raman, photoluminescence, UV and IR. The activity of the catalyst was probed through one-pot four-component reaction of aldehydes, ketones and two equivalent propanedinitriles in water without requiring any additives or anhydrous conditions. The reaction requires two different catalytic functions, i.e., an acidic one which is given by Ti(iv) ions and a basic one, given by the oxide ion incorporated within the ZnTiO sub(3) metal oxide framework. The advantages of this method lie in its simplicity, cost effectiveness, environmental friendliness, and easier scaling up for large scale synthesis without using high pressure, temperature and toxic chemicals. As water was used as a reaction medium and since we are particularly interested in the isolation of a non-aromatic intermediate, the elimination of poisonous HCN was prevented by the Lewis acid character of Ti super(4+) up to a sufficiently high temperature. Thus, this process can be considered as a "green" process. Elimination of HCN at higher temperatures still maintains "green" attributes as HCN can be trapped by the basic catalyst under such conditions. Spontaneous generation of low molecular mass self-aggregated organic materials, their one-dimensional packing, and interesting photophysical properties are reported.