Manganese (iii) acetylacetonate preparation method

FIELD: catalyst preparation methods.

SUBSTANCE: invention relates to preparation of manganese (III) acetylacetonate, which can be used as catalyst as well as vinyl monomer polymerization initiator. Method is implemented in aqueous medium with ammonium acetylacetonate freshly prepared by mixing acetylacetone with aqueous ammonia solution. Hydrogen peroxide is used as oxidant and sodium bicarbonate is additionally introduced into reaction mixture. Following consecutive operations are carried out: reaction of manganese (II) chloride tetrahydraye with sodium bicarbonate; separating thus formed manganese (II) bicarbonate in the form of paste; adding ammonia acetylacetonate and then hydrogen peroxide aqueous solution to the paste; and recovering manganese (III) acetylacetonate with yield 95%.

EFFECT: improved economical and environmental characteristics of process.

The invention relates to the production of acetylacetonate and manganese (III) - Tris(2,4-pentanedionato) manganese (III), which is used as a catalyst for the oxidation of alkyl compounds as a reagent for selective changes of chemical shift in NMR spectroscopy, as well as the initiator of polymerization of vinyl monomers, in particular styrene.

A method of obtaining manganese acetylacetonate (III) by reacting chloride tetrahydrate manganese (II), acetylacetone, sodium acetate and potassium permanganate /J.Phys / Chem., 62, 440 (1958)/.

This method allows the synthesis in the aquatic environment. The disadvantages of the method include low yield of the target product (manganese not more than 70%), the presence of the target product of several by-products that require a thorough cleaning and entails the presence of an unacceptably large for tonnage production quantities of liquid waste. These shortcomings virtually preclude the use of this method for industrial production of manganese acetylacetonate (III).

Also known is a method of obtaining manganese acetylacetonate (III) by reacting a hydroxide of manganese (III) with a 2-10-fold excess acetoacetate without solvent at 50 to 150° /U.S. Patent No. 3474464, 1968/.

The known method does not allow to obtain the target is not already installed, with significant output and refers to laboratory methods for producing manganese acetylacetonate (III).

In addition, a method of obtaining manganese acetylacetonate (III) interaction with potassium permanganate polutorakratnom excess acetylacetone /the Federal Republic of Germany Patent No. 2420775, 1975/.

This method can be used for the industrial production of manganese acetylacetonate (III), however, it requires the use of potassium permanganate, which is currently imported raw materials, in addition, the product yield for manganese is 86%.

The closest in technical essence of the present invention is a method of obtaining manganese acetylacetonate (III) the interaction of chloride tetrahydrate manganese (II)acetylacetonate ammonium and oxidizer - oxygen /the Federal Republic of Germany Patent No. 1039056, 1956/.

The interaction of the components is carried out in absolute ethanol or tetrahydrofuran, which, despite the high yield of the target product (manganese 95%), which allows its industrial getting complicated due to the need for disposal of contaminated organic solvents and dramatically increases the cost of the technology process, and also reduces its safety and environmental friendliness.

The technical problem of the invention is the development of an industrial method of producing manganese acetylacetonate (III) if the elimination of these shortcomings.

The technical result of the invention is to PR the industrial obtain the target product with high yield when using the cheapest available raw materials, as well as to improve safety and environmental friendliness of the process.

This technical result is achieved due to the fact that in the method of producing manganese acetylacetonate (III) the interaction of chloride tetrahydrate manganese (II)acetylacetonate ammonium and oxidant, the process is carried out in aqueous medium, using ammonium acetylacetonate freshly prepared by mixing of acetylacetone with an aqueous ammonia solution as the oxidant used the hydrogen peroxide and the reaction mixture was further added sodium bicarbonate, and consistently interact chloride tetrahydrate manganese (II) with sodium bicarbonate, the Department received carbonate manganese (II) in the form of paste, the introduction of ammonium acetylacetonate, the Department received acetylacetonate and manganese (II in paste form, the introduction of its acetylacetonate ammonia, and then the aqueous hydrogen peroxide solution, followed by separation of the obtained manganese acetylacetonate (III).

The process is carried out at room temperature without the use of organic solvents. When using the component ratio close to the stoichiometric yield of the product at each stage of the downloaded source components increases. Use aqueous solutions of the starting components having any time convenient for mixing Konz is Tracii.

Using acetylacetonate ammonia freshly prepared by mixing the ammonia and acetylacetone, using as the oxidant hydrogen peroxide, as well as the introduction of components into the product of the previous stage, which is a paste, allow in more environmentally acceptable conditions in terms of the water environment - not to reduce the yield of the target product in comparison with the closest analogue, i.e. save it to a level where you can use the method on an industrial scale.

An example of carrying out the invention

A solution of 50 g of tetrahydrate of manganese chloride (II) in 100 ml of water poured into a solution of 40 g of sodium bicarbonate in 400 ml of water and stirred at room temperature for 30 minutes the Precipitate is decanted and washed with water.

In the resulting paste containing 0,245 M carbonate of manganese, pour in a solution of ammonium acetylacetonate, which is previously obtained by blending 0,257 M acetylacetone and 25%ammonia solution in water to remove the oily layer. The mixture is stirred at room temperature for 30 minutes the Precipitate is decanted and washed with water.

In the resulting paste containing 0,237 M acetylacetonate manganese (II), pour in a solution of ammonium acetylacetonate, which is previously obtained by blending 0,245 M acetylacetone and 25%ammonia solution in water to remove the oily layer. Then,under stirring, was added dropwise over 45 min to 150 ml of 10%aqueous hydrogen peroxide solution and stirred for further at room temperature for 30 minutes the Precipitate is filtered off, washed with water, sucked off over a Buechner funnel and dried in air at 50°C for 1 hour.

The product yield (manganese) is 80 g (95%). The content of manganese acetylacetonate (III) of 99.9%. The composition of the product was confirmed by spectral analysis.

A method of producing manganese acetylacetonate (III) the interaction of chloride tetrahydrate manganese (II)acetylacetonate ammonium and oxidant, wherein the process is carried out in aqueous medium, using ammonium acetylacetonate, freshly prepared by mixing of acetylacetone with an aqueous ammonia solution as the oxidant used the hydrogen peroxide and the reaction mixture was further added sodium bicarbonate, and consistently interact chloride tetrahydrate manganese (II) with sodium bicarbonate, the Department received carbonate manganese (II) in the form of paste, the introduction of ammonium acetylacetonate, the Department received acetylacetonate and manganese (II) in the form of paste, introduction it acetylacetonate ammonia, and then the aqueous hydrogen peroxide solution, followed by separation of the obtained manganese acetylacetonate (III).