Clays and catalysis: a promising future

1 Review 1.1 Overview 1.2 Solid-phase organic synthesis (SPOS) 1.3 Beyond conventional solid-phase organic synthesis 1.4 The review 1.5 Some definitions 1.6 Solid-supported reagents and scavengers 1.7 Multi-step use of solid-supported reagents and scavenging reagents 1.8 Conclusions and future perspective 2 Introduction to the tables 2.1 Organisation of tables (reagent and catalyst section) 2.2 Representative data entry (reagent and catalyst section) 2.3 Organisation of tables (scavenging agents section) 2.4 Representative data entry (scavenging agents section) 3 Tables of reagents and catalysts 4 Tables of scavengers 5 Other relevant reviews 5.1 Insoluble polymers 5.1.1 Structure and physical properties (insoluble polymers) 5.1.2 General (insoluble polymers) 5.1.3 Reactions (insoluble polymers) 5.1.4 Miscellaneous (insoluble polymers) 5.2 Soluble polymers 5.2.1 General (soluble polymers) 5.2.2 Reactions (soluble polymers) 5.3 Inorganic solids 5.3.1 Structure and physical properties (inorganic solids) 5.3.2 General (inorganic solids) 5.3.3 Reactions (inorganic solids) 5.3.4 Miscellaneous (inorganic solids) 5.4 Miscellaneous supports 5.4.1 Structure and physical properties (miscellaneous supports) 5.4.2 General (miscellaneous supports) 5.4.3 Reactions (miscellaneous supports) 5.4.4 Miscellaneous (miscellaneous supports) 5.5 Purification strategies 5.5.1 Various supports (purification strategies) 5.5.2 Insoluble polymers (purification strategies) 6 Acknowledgements 7 Abbreviations 8 References 1 Review

Multi-step organic synthesis using solid-supported reagents and scavengers: a new paradigm in chemical library generation

FeCl3–SiO2 as a reusable heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles via [2+3] cycloaddition of nitriles and sodium azide

Organic synthesis using clay and clay-supported catalysts

Catalysis has been an important field for polyurethane chemistry and many improvements have been accomplished in recent years. Some of the greatest challenges however still remain. There is not yet a satisfactory catalytic way for the direct oxidation of propene to propene oxide in spite of ruthless activities by all major players over decades. New methods of catalysts screening and improved tools for catalyst characterization may help to solve this problem in the near future. Catalyst development in the area of polyether synthesis has recently opened new routes to completely new products. New raw materials may become attractive and new polyether polyol structures will be accessible with new catalysts. The range of new polymers will open up new opportunities. In the field of isocyanates the optimization of all manufacturing steps (nitration, hydrogenation, phosgenation) is an ongoing process since commercial production started an incremental improvements are accomplished and implemented constantly. Major improvements for existing processes, including all their catalytic reaction steps, are not to be expected in the near future. Significant improvements seem only possible by alternative ways of isocyanate manufacturing. In this area, catalytic reactions and the modern tools of catalysts research will play a key-role. However, as for all new developments, they will have only a chance on realization on a commercial scale, if they are economically competitive to well established processes.

Trends in industrial catalysis in the polyurethane industry

A comparative study on H2SO4, HNO3 and HClO4 treated metakaolinite of a natural kaolinite as Friedel–Crafts alkylation catalyst

Natural Kaolinitic clays containing transition metals Fe and Ti in their lattice have been examined for their acidic properties and catalytic activity for the alkylation of benzene with benzyl chloride. Calcination of the clays at 550 °C and subsequent acid-activation using 2 M HCl (1 M = 1 mol dm−3) rendered the kaolinite surface highly acidic with very high acid amount. These clays exhibited high catalytic activity and selectivity for the conversion of benzyl chloride to diphenylmethane. Al(III), Fe(II), and Ti(II) ions exsolved from the lattice of kaolinites by acid activation relocate in the interlamellar space and boost the Bronsted acidity of coordinated hydroxo and proposed to initiate the alkylation. In fact kaolinites having structural transition metal, on acid activation exhibited higher acid amount and enhanced catalytic activity than kaolinites devoid of transition metals and recently studied alkylation catalysts such as synthetic TiO2–SiO2–Al2O3 and Fe2O3–SiO2–Al2O3. Natural kaolinitic clays ...

M. Lalithambika

Papers

A comparative study on H2SO4, HNO3 and HClO4 treated metakaolinite of a natural kaolinite as Friedel–Crafts alkylation catalyst

Acidic properties and catalytic activity of natural kaolinitic clays for Friedel-Crafts alkylation

Natural bentonite clay/dilute hno3 (40%)—a mild, efficient, and reusable catalyst/reagent system for selective mono nitration and benzylic oxidations

An easy synthesis of 4,4′-di- aminodiphenylmethanes. on natural kaolinites

Modified Clays as Efficient Acid–Base Catalyst Systems for Diazotization and Diazocoupling Reactions