Hydrogen peroxide fine chemical manufacture

Liquid-liquid reactions occur between two or more liquid phases whereby a system consisting of an organic and an aqueous phase is applied most frequently. Usually reaction takes place in one phase only. Phase-transfer catalysts are sometimes used to make transfer of a reactant to the reacting phase easier. Among typical liquid-liquid reactions utilized in fine chemicals manufacture are nitrations with mixtures of nitric and sulphuric acid, conventional hydroxylations performed with hydrogen peroxide, esterifications, alkylations, brominations, and iodinations. 

The subject of catalytic oxidation with hydrogen peroxide is an area in which many exciting new developments are taking place. The driving force behind these investigations is the need for cleaner processes, particularly in fine chemical manufacture, and shorter routes with higher product selectivity. In... 

Hydrogen peroxide is a large-scale manufactured chemical compound due to its application as a disinfectant and in bleaching, although it also has an important use as a reactant in many minor-scale fine-chemical productions. 

In bulk chemicals manufacture economic considerations usually dictate the use of molecular oxygen as the oxidant. In fine chemicals, on the other hand, other oxidants may be commercially feasible (see table 1). Indeed, other oxidants (e.g. 30% hydrogen peroxide) may even be preferred for reasons of selectivity and ease of handling, i.e. it is not a question of price per se but price/performance ratio. Although molecular oxygen is the least expensive oxidant it requires elaborate safety precautions, and the associated costs, in order to avoid working within explosion limits. 

The key to the success of the oxidation examples cited above is the ability of the catalysts used to exert proper kinetic control on the possible side reactions. Without it, thermodynamically favorable but undesired products such as CO2 and H2O are made instead. Controlling oxidation kinetics to stop at the desired oxygenated products is quite difficult, and has yet to be solved for many other systems. For instance, although many attempts have been made to develop a commercial process for the oxidation of propylene to propylene oxide, both the activity and the selectivity of the systems proposed to date, mostly based on silver catalysts, are still too low to be of industrial interest " propylene oxide is presently manufactured by processes based on chlorohydrin or hydrogen peroxide instead. In spite of these difficulties, though, recent advances in selective liquid phase oxidation of fine chemicals on supported metal catalysts have shown some promise, offering high yields (close to 100%) under mild reaction conditions." ... 

The heterogeneous epoxidation of compounds which contain carbon-carbon double bonds is an important industrial process in both the manufacture of fine chemicals and in the synthesis of natural products. A number of studies have demonstrated that alkenes can be readily epoxidised by hydrogen peroxide using the titanium silicalite TS-1 11 -3. However, it has been found that substitution of the alkene by electron withdrawing groups significantly decreases the reactivity of the carbon-carbon double bond since the decrease of the electron... 

This review examines the work carried out either in-house or via external research contracts by Solvay Interox into the area of heterogeneously activated aqueous hydrogen peroxide chemistry. The review is focused on the preparation and use of solid catalysts in the presence of H2O2 for the manufacture of fine chemical and pharmaceutical intermediates. 

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