OXIDIZING AGENTS
CHEMICAL SYNTHESIS
Most organic chemists know m-chloro-peroxybenzoic acid as a versatile oxidant for selective oxidations from the laboratory. However, this reagent is expensive and too difficult to handle to be used on an industrial scale. An alternative oxidizing agent with similar reactivity that is suitable for industrial purposes is peracetic acid. For various numbers of oxidations also hydrogen peroxide can be used.
Hydrogen Peroxide
Hydrogen peroxide is an economical but powerful and environmentally friendly oxidizing agent that has found many uses in the chemical industry for the manufacture of organic compounds. Due to its low molecular weight, hydrogen peroxide is a more efficient oxidizing agent on a weight per weight basis than potassium dichromate or permanganate. It is a stable and safe chemical when handled correctly and offers the advantage of being soluble in water, in many organic solvents, or in the substrate itself. Last but not least, hydrogen peroxide has an environmentally friendly profile since it decomposes to just water and oxygen.
The various applications where hydrogen peroxide is used as the oxidizing agent of choice include the following examples in chemical synthesis:
- Propylene oxide (alkene epoxidation via HPPO process)
- Organic peroxide initiators (e.g. benzoyl peroxide, lauryl peroxide)
- Epoxidized soy bean oil plasticizers (fatty acid epoxidation)
- Flame retardants (bromination)
- Initiator for catalytic polymerization reactions (free radical source)
- Catechol production (hydroxylation)
- Preparation of pharmaceutical precursors (oxidation)
- Amine oxide surfactants (N-oxidation)
- Herbicide production (S-, N-oxidation)
- Percarboxylic acid production (e.g. peracetic acid)
Depending on the initial quality requirements for chemical synthesis applications, Evonik offers various hydrogen peroxide grades including technical and chlorate grades as well as high purity hydrogen peroxide grades under the brand names HYPROX® and PERSYNT®. Technical grade is frequently used in the synthesis of organic chemicals such as epoxides, organic peroxides and amine oxides. It is lightly stabilized for applications that are sensitive to residues or precipitates. Chlorate grade is formulated specially for hypochlorite control in chlorate cells and will not interfere with electrode performance.
Peracetic Acid
Peracetic acid in concentrations are used in chemical synthesis, bleaching, sanitization, disinfection and sterilization. They dissolve easily in water and decompose into non-toxic by-products. Evonik offers PERACLEAN® 35 and PERACLEAN® 40, high strength equilibrium peracetic acid grades which are the products of choice for chemical synthesis.
High strength PERACLEAN® grades offer unique properties as an oxidant:
- High oxidation power
- Selective reactions by nonradical pathways
- Safe and convenient liquid handling
- No transition metals involved
- No halogenated by-products
- Effluents are readily biodegradable
- Available ready-to-use in large quantities at a competitive price
PERACLEAN® 35 and PERACLEAN® 40 can be used for a wide range of oxidation reactions such as:
- Epoxidation of olefins
- Oxidation of thioethers to sulfoxides or sulfones
- Oxidation of tert. amines to amine oxides
- Oxidation of pyridines to pyridine oxides
- Baeyer-Villiger oxidation of acylbenzenes to o-acylphenols
Persulfates
Persulfates are used as oxidizing agents in the production of aldehydes, ketones, carboxylic acids, quinones and a variety of other compounds. In the pharmaceutical industry, sodium persulfate is used as a reagent for the production of antibiotics.