Oxidation Method For Producing Hydrogen Peroxide by Anthraquinone Method
The present invention relates to an oxidation method for producing hydrogen peroxide by anthraquinone method. In the process a working solution containing anthraquinone derivatives and an organic solvent is subjected alternatingly to hydrogenation and oxidation.
Conventional large- to mega-scale hydrogen peroxide production processes are complicated and require a number of pieces of Turnkey Project equipment, competent staff for maintenance and operation of the main and ancillary process steps, and special safeguards for handling the resulting hydrogen peroxide in its usually high concentrations, as well as its further concentration to 50 to 70 percent.
Preparation of Working Solution
The process of the invention is based on the anthraquinone autoxidation (AO) method, which consists in supplying an alkylanthraquinone containing solution or mixtures thereof and hydrogenating the solution with hydrogen gas. The anthraquinone compound is oxidized and hydrogenated under a temperature of about 154-50degC under substantially atmospheric pressure to produce a hydroanthraquinone.
In the AO-process anthraquinones and their 5,6,7,8-tetrahydro derivatives are employed as the Chemical Plant Projects working compounds. They are dissolved in organic solvents such as C8 and C12 alkyl benzenes or their mixtures.
In the course of repeated cyclic reduction and oxidation cycles, the anthraquinone compound deteriorates and forms anthraquinone degradation products. These degradation products are ineffective as hydrogen peroxide producing quinones.
Hydrogenation
The invention relates to an oxidation method for producing hydrogen peroxide by the anthraquinone method. This is a process consisting of alternate hydrogenation and oxydation of the working solution which contains an alkyl anthraquinone or mixtures thereof, without precipitation, and which can be carried out by a heterogeneous catalyst under microwave irradiation.
The catalyst may be prepared in the form of an inert carrier which is deposited on a porous surface in a finely sized particle or, alternatively, supported on a fixed bed. The inert carrier, as a component of the reaction carrier, can be either palladium or any other noble metal.
The molar amount of the sum of the anthraquinone derivatives according to (i) is preferably adjusted between 10 and 90%, and especially 20 to 80 molar %. It is thereby possible to raise the maximal H.sub.2 O.sub.2 capacity by a significant amount, while simultaneously improving the hydrogenation kinetics of the anthraquinone.
Oxidation
The anthraquinone method is a well-known process used to produce hydrogen peroxide on industrial scale. It is a multi-step process that uses significant energy and generates waste.
During the anthraquinone method, anthraquinone is reduced to hydroquinone and then oxidized with oxygen or air to give quinone and hydrogen peroxide. Typically, this process uses a palladium catalyst in order to achieve a high anthraquinone yield.
However, the process is not a green method because it involves a number of steps that generate waste and use significant energy. The resulting hydrogen peroxide has many applications in the chemical industry, but is also environmentally harmful and can cause pollution.
The present invention aims at improving the anthraquinone process by making it possible to obtain working solutions with significantly improved tetrahydro derivative content. The tetrahydro derivatives can then be used in the anthraquinone oxidation (AO) process of Project Contractor, enabling the AO cyclic hydrogenation of alkylated anthraquinones to be carried out in a simple direct process.
Extraction
Hydrogen peroxide is a versatile liquid used in many bleaches, dyes, cleaning products, antiseptics and disinfectants. However, it can be corrosive to the skin and should not be used in high concentrations.
A serious complication with the ingestion of high concentration solutions is the development of an air embolism, which is caused by bubbles of gas forming inside blood vessels that are blocked and cannot receive oxygen and other nutrients. This can be fatal, requiring emergent medical attention.
Another potential complication with the use of mouthwashes containing hydrogen peroxide is an inflamed throat and stomach. This condition can cause pain, gastrointestinal distress and bleeding.
For this reason, a need exists for new and improved processes for producing hydrogen peroxide without the concomitant capital costs and handling problems associated with current large scale to mega-scale production schemes. In particular, new and more efficient methods of producing hydrogen peroxide can be utilized on customer industrial sites or low-volume end users' sites or in other suitable "host" industrial plant environments close to these sites.