METHOD FOR PRODUCING ACETYLACETONATE FROM A HYDRATED OR ANHYDROUS CHEMICAL ELEMENT

Abstract

A process for the preparation of the hydrated and/or anhydrous acetylacetonate of a chemical element Me, where the chemical element Me is chosen from alkaline earth metals, transition metals and lanthanides, comprises a stage of reaction in an aqueous medium of the Me oxide or hydroxide introduced in the solid form and of acetylacetone, the acetylacetone being in excess with respect to the Me oxide or hydroxide.

Claims

1.-15. (canceled)

16. A process for the preparation of an acetylacetonate of a chemical element Me, the acetylacetonate being hydrated, anhydrous or both hydrated and anhydrous, where the chemical element Me is selected from the group consisting of alkaline earth metals, transition metals and lanthanides, comprising: reacting Me oxide or hydroxide in a solid form with acetylacetone, in an aqueous medium, the acetylacetone being in excess with respect to the Me oxide or hydroxide.

17. The process according to claim 16, wherein an acetylacetone/Me oxide or hydroxide molar ratio is greater than 2 when the Me oxide or hydroxide is divalent or greater than 3 when the Me oxide or hydroxide is trivalent.

18. The process according to claim 16, wherein the chemical element Me is selected from alkaline earth metals selected from the group consisting of magnesium, calcium, strontium and barium.

19. The process according to claim 16, wherein the chemical element Me is selected from transition metals selected from the group consisting of cobalt, nickel, copper and zinc.

20. The process according to claim 16, wherein the chemical element Me is selected from lanthanides selected from the group consisting of lanthanum, cerium, praseodymium and neodymium.

21. The process according to claim 16, wherein Me is selected from the group consisting of cobalt, magnesium, nickel, calcium, neodymium and zinc.

22. The process according to claim 19, wherein Me is cobalt and cobalt acetylacetonate dihydrate is obtained by reacting cobalt(II) hydroxide and acetylacetone in water.

23. The process according to claim 18, wherein Me is magnesium and magnesium acetylacetonate dihydrate is obtained by reacting magnesium(II) hydroxide or magnesium oxide and acetylacetone in water.

24. A continuous batchwise process for a synthesis of hydrated or anhydrous acetylacetonate of a chemical element Me, where the chemical element Me is selected from the group consisting of alkaline earth metals, transition metals and lanthanides, comprising: n steps of (i) reacting an Me oxide or hydroxide in a solid form with acetylacetone, in an aqueous medium, the acetylacetone being in excess with respect to the Me oxide or hydroxide; n steps of (i′) filtering the reaction mixture after each step (i); and n−1 steps of recovering a liquid filtrate comprising water, the excess acetylacetone and a fraction of dissolved Me acetylacetonate, and recycling the liquid filtrate to a next step (i), wherein n is greater than or equal to 2.

25. The continuous batchwise process according to claim 24, wherein, for each step (i), an acetylacetone/Me oxide or hydroxide molar ratio is greater than 2 when the Me oxide or hydroxide is divalent and greater than 3 when the Me oxide or hydroxide is trivalent.

26. The continuous batchwise process according to claim 24, wherein a weight of acetylacetone in an aqueous phase of the liquid filtrate is less than or equal to 15% of a weight of the aqueous phase.

27. The continuous batchwise process according to claim 24, wherein the chemical element Me is selected from the group consisting of cobalt, magnesium, nickel, calcium, neodymium and zinc.

28. The continuous batchwise process according to claim 24, wherein hydrated acetylacetonate of the chemical element Me recovered after each filtration step (i′) is dried.

29. A process for a preparation of hydrated or anhydrous acetylacetonate of a chemical element Me, where the chemical element Me is selected from the group consisting of alkaline earth metals, transition metals and lanthanides, the process comprising: reacting an Me oxide or hydroxide and acetylacetone, wherein Me acetylacetonate, a liquid filtrate containing acetylacetone in an aqueous phase, and a condensate are obtained, the liquid filtrate being capable of being used for a new preparation of acetylacetonate of the element Me.

30. The process according to claim 29, wherein the reacting step comprises a first stage of reacting the Me oxide or hydroxide in a solid form with acetylacetone, in an aqueous medium, the acetylacetone being in excess with respect to the Me oxide or hydroxide, and a second stage of filtering.

Description

EXAMPLES

[0065] The characterization tests used in the examples are as follows.

[0066] Mg Level by Complexometry in Magnesium Acetylacetonate

[0067] The magnesium contained in magnesium acetylacetonate is released into the aqueous phase by dissolving in acetone and then hydrolysed by a hydrochloric acid solution.

[0068] The manipulation consists of a quantitative determination of the magnesium ions (Mg.sup.2+) of the sample by EDTA in the presence of a coloured indicator: Eriochrome Black T (denoted EBT). The end of quantitative determination is detected by a Phototrode set at 660 nm.

[0069] At the start of quantitative determination, the EBT complexes with the magnesium ions present, which gives a purplish colour to the solution.

[0070] The magnesium ions complex preferentially with the EDTA. At the end of the quantitative determination, all the magnesium ions will have complexed with the EDTA. The coloured indicator (EBT) will thus recover its free form and its initial colour: bluish. This change in colour is monitored by the abovementioned Phototrode.

[0071] The total hardness corresponds to the amount of EDTA (denoted H2Y2-) used to reach the colour change.

[0072] Co Level by Complexometry in Cobalt Acetylacetonate

[0073] The cobalt contained in cobalt acetylacetonate is released into the aqueous phase by dissolving in acetone and then hydrolysed by a hydrochloric acid solution.

[0074] The manipulation consists of a quantitative determination of the cobalt ions of the sample by EDTA in the presence of a coloured indicator: Xylenol Orange. The end of quantitative determination is detected by the visual observation of a change in colour.

[0075] At the start of quantitative determination, the Xylenol Orange complexes with the cobalt ions present, which gave the solution a pinkish colour.

[0076] The cobalt ions complex preferentially with the EDTA. At the end of the quantitative determination, all the cobalt ions will have complexed with the EDTA. The coloured indicator (Xylenol Orange) will thus recover its free form and its initial colour: orange. This change in colour is monitored visually.

[0077] The total hardness corresponds to the amount of EDTA (denoted H2Y2-) used to reach the colour change.

[0078] Mg Level by Spectrophotometry in Magnesium Acetylacetonate

[0079] Magnesium acetylacetonate is hydrolysed in an acidified aqueous solution (for example with hydrochloric acid) under hot conditions. Once the magnesium acetylacetonate has completely dissolved, the solution thus obtained is analysed by ICP (Inductively Coupled Plasma) coupled to an atomic emission spectrophotometry (AES) detector. During its introduction into the ICP-AES, the elements present in the solution will be excited on contact with the plasma. During their return to their ground state, they will emit radiation, the wavelength of which will be representative of their chemical nature. Thus, by detecting the intensity of the radiation at the wavelength corresponding to magnesium, it will be possible to determine its content in the solution.

[0080] Co Level by Spectrophotometry in Cobalt Acetylacetonate

[0081] Cobalt acetylacetonate is hydrolysed in an acidified aqueous solution (for example with nitric acid). Once the cobalt acetylacetonate has completely dissolved by stirring, the solution thus obtained is analysed by ICP (Inductively Coupled Plasma) coupled to an atomic emission spectrophotometry (AES) detector. During its introduction into the ICP-AES, the elements present in the solution will be excited on contact with the plasma. During their return to their ground state, they will emit radiation, the wavelength of which will be representative of their chemical nature. Thus, by detecting the intensity of the radiation at the wavelength corresponding to cobalt, it will be possible to determine its content in the solution.

Example 1

[0082] Magnesium acetylacetonate dihydrate is synthesized.

[0083] The reaction is carried out starting from magnesium hydroxide and a molar excess of acetylacetone (acetylacetone/magnesium hydroxide molar ratio=6).

[0084] On conclusion of the reaction, the aqueous filtrate containing the excess acetylacetone and dissolved magnesium acetylacetonate is entirely recycled in a following synthesis. Thus, the operation is repeated 7 times.

[0085] The initial aqueous dilution is advantageously calculated in order to be able to retain a homogeneous aqueous phase for the filtrate. This limit is reached when the weight of acetylacetone in the water approaches 15%. When this limit is exceeded, a supernatant organic phase will appear in the filtrate. This situation can make the filtration more difficult. The experimental conditions are as follows:

[0086] Reaction 1:

[0087] The magnesium hydroxide is suspended in water in a 11 reactor and the acetylacetone is added in full with stirring to this aqueous suspension. The reaction time is 4 hours. Reaction very slightly exothermic (+10° C. the 1st half hour).

[0088] Raw water: 750 ml

[0089] +Magnesium hydroxide Mg(OH).sub.2: ˜19 g

[0090] (0.32 mol×58.32 g/mol×1/0.99 (purity)=18.85 g)

[0091] +Acetylacetone: ˜200 ml

[0092] (0.32 mol×6(acetylacetone/Mg)×100.12 g/mol×1/0.995 (purity)×1/0.975 (density)=198.15 ml)

[0093] Reaction 2:

[0094] The magnesium hydroxide is added in full to the filtrate of reaction 1 (first without stirring) and then the acetylacetone and the additional water (correction of the loss associated with the drying in so far as, in this example, there is no recycling of the condensate) are added with stirring to this suspension. The reaction time is 4 hours.

[0095] Filtrate reaction 1: ˜840 ml

[0096] Water: ˜40 ml (compensation for significant loss associated with the drying)

[0097] +Magnesium hydroxide Mg(OH).sub.2: ˜19 g

[0098] (0.32 mol×58.32 g/mol×1/0.99 (purity)=18.85 g)

[0099] +Acetylacetone: ˜70 ml (compensation for slight loss ˜4 ml associated with the drying)

[0100] (0.32 mol×2(acetylacetone/Mg)×100.12 g/mol×1/0.995 (purity)×1/0.975 (density)=66.05 ml)

[0101] Reaction 3:

[0102] The acetylacetone and the additional water are added to the filtrate from reaction 2 with stirring (the reverse, namely the filtrate to the acetylacetone and additional water, is also possible). The magnesium hydroxide is added in small portions to the water/acetylacetone reaction medium (slightly two-phase but well stirred at ˜500 rpm). The addition (by spatula) lasts between 10-15 min. The total reaction time (4 h) encompasses this addition time.

[0103] Filtrate reaction 2: ˜840 ml

[0104] Water: ˜40 ml

[0105] +Acetylacetone: ˜70 ml

[0106] +Magnesium hydroxide Mg(OH).sub.2: ˜19 g

[0107] Reaction 4:

[0108] Same protocol as reaction 3.

[0109] Filtrate reaction 3: ˜840 ml

[0110] Water: ˜40 ml

[0111] +Acetylacetone AAH: ˜70 ml

[0112] +Magnesium hydroxide Mg(OH).sub.2: ˜19 g

[0113] Reaction 5:

[0114] Same protocol as reaction 4.

[0115] Reaction 6:

[0116] Same protocol as reaction 5.

[0117] Reaction 7:

[0118] Same protocol as reaction 6.

[0119] Reaction 8:

[0120] Same protocol as reaction 7.

[0121] After each reaction, the filtration is carried out on a sintered glass (No. 3). The filtration of the white precipitate is quick and easy. The product is left for 15-20 minutes under a vacuum of approximately 150 mbar. The filtrate is clear and coloured golden-yellow with a slight odour of β-diketone. The pH of this filtrate, measured with pH paper, is approximately 6. The volume collected is ˜840 ml. No washing is carried out on the filter cake, the liquid filtrate being directly recovered for the following synthesis.

[0122] Drying

[0123] The magnesium acetylacetonate obtained is dried in order to obtain either an anhydrous form or a dihydrated form with, for the latter, less severe drying conditions.

[0124] Thus, for an anhydrous form, the conditions of the drying in an oven are a temperature of 50° C. under a vacuum of approximately 60 mbar regulated with slight nitrogen flushing, until a constant weight is obtained.

[0125] Thus, for a dihydrated form, the conditions of the drying in an oven are a temperature of 50° C. under a vacuum of approximately 500 mbar regulated with slight nitrogen flushing, until a constant weight is obtained.

[0126] The characterizations of the magnesium acetylacetonate obtained are given in Table 1.

TABLE-US-00001 TABLE 1 Regulated % Mg drying with ICP-AES slight nitrogen (optical % H.sub.2O flushing to emission Karl- Loss on stoving % C constant weight spectrometry) Complexometry Fischer (2 h at 100° C.) Microanalysis Reaction 3 50° C.-60 mbar 10.83 10.92 0.2 53.4 Reaction 7 50° C.-60 mbar 10.96 Anhydrous 10.92  0.00 53.98 MgAA.sub.2 (theory) Reaction 7  50° C.-500 mbar 9.44 14.2 MgAA.sub.2  9.40 13.94 46.46 dihydrate (theory)

[0127] The yield of magnesium acetylacetonate (anhydrous or dihydrate) calculated from the amount of magnesium hydroxide introduced is given for each reaction in Table 2. For example, the yield for reaction 7 is 96% (79.5 g of product obtained) if it is considered that the product is in the dihydrate form (258.55 g/mol). The theoretical level of magnesium is 9.40%. This yield illustrates the loss of magnesium acetylacetonate by dissolution in the filtrates and the advantage of recovering these filtrates.

TABLE-US-00002 TABLE 2 Yield (% by Reaction weight) 1 86 2 82 3 92 4 92 5 94 6 95 7 96 8 94

Example 2

[0128] Cobalt acetylacetonate dihydrate is synthesized.

[0129] The reaction is carried out starting from cobalt(II) hydroxide and a molar excess of acetylacetone (acetylacetone/cobalt hydroxide molar ratio=6).

[0130] On conclusion of the first reaction, the aqueous filtrate containing the excess acetylacetone and dissolved cobalt acetylacetonate is entirely recycled in a following synthesis. Thus, the operation is repeated 3 times.

[0131] The initial aqueous dilution is advantageously calculated in order to be able to retain a homogeneous aqueous phase for the filtrate. This limit is reached when the weight of acetylacetone in the water approaches 15%. When this limit is exceeded, a supernatant organic phase will appear in the filtrate. This situation can make the filtration more difficult. The experimental conditions are as follows:

[0132] Reaction 1:

[0133] The cobalt hydroxide is suspended in water in a 11 reactor and the acetylacetone is added in full with stirring to this aqueous suspension. The reaction time is 4 hours. Slightly exothermic reaction.

[0134] Raw water: 750 ml

[0135] +Cobalt hydroxide Co(OH).sub.2: ˜30 g

[0136] (0.32 mol×92.95 g/mol×1/0.99 (purity)=30.04 g)

[0137] +Acetylacetone: ˜200 ml

[0138] (0.32 mol×6(acetylacetone/Co)×100.12 g/mol×1/0.995 (purity)×1/0.975 (density)=198.15 ml)

[0139] Reaction 2:

[0140] The Co(II) hydroxide is added in full to the filtrate of reaction 1 (suspended with stirring) and then the acetylacetone and the additional water (correction of the loss associated with the drying in so far as, in this example, there is no recycling of the condensate) are added with stirring to this suspension. The reaction time is 4 hours at ambient temperature with stirring (˜500 rpm).

[0141] Filtrate reaction 1: ˜840 ml

[0142] Water: ˜40 ml (compensation for significant loss associated with the drying)

[0143] +Cobalt hydroxide Co(OH).sub.2: ˜30 g

[0144] (0.32 mol×92.95 g/mol×1/0.99 (purity)=30.04 g)

[0145] +Acetylacetone: ˜70 ml (compensation for slight loss ˜4 ml associated with the drying in so far as, in this example, there is no recycling of the condensate)

[0146] (0.32 mol×2(acetylacetone/Co)×100.12 g/mol×1/0.995 (purity)×1/0.975 (density)=66.05 ml)

[0147] Reaction 3:

[0148] Same protocol as reaction 2.

[0149] Filtrate reaction 2: ˜840 ml

[0150] Water: ˜40 ml

[0151] +Cobalt hydroxide Co(OH).sub.2: ˜30 g

[0152] +Acetylacetone AAH: ˜70 ml

[0153] After each reaction, the filtration is carried out on a sintered glass (No. 3 or 4). The filtration of the salmon pink precipitate is quick and easy. The product is left for 15-20 minutes under bench vacuum. The filtrate is clear and coloured red with a slight odour of β-diketone. The pH of this filtrate is approximately 5 (pH paper). The volume collected is ˜840 ml. No washing and recovery of the filtrate for the following synthesis.

[0154] Drying

[0155] The cobalt acetylacetonate obtained is dried in order to obtain an anhydrous form. The conditions of drying in an oven are a temperature of 50° C. under a vacuum of approximately 250 mbar regulated with slight air or nitrogen flushing, to a constant weight.

[0156] The colour of the product obtained (salmon pink) makes it possible to observe that the product obtained is indeed cobalt acetylacetonate dihydrate.

[0157] The characterizations of the cobalt acetylacetonate obtained are given in Table 3.

TABLE-US-00003 TABLE 3 Regulated % Co drying with ICP-AES slight nitrogen (optical % H.sub.2O Appearance flushing to emission Loss on stoving Colour of constant weight spectrometry) Complexometry (4 h at 75-80° C.) the crystals Reaction 2 50° C.-250 mbar 20.16 20.08 12.0 salmon pink CoAA.sub.2 20.10 12.29 salmon pink dihydrate (theory) Anhydrous 22.92 0.00 burgundy CoAA.sub.2 purple (theory)

[0158] The yield of cobalt(II) acetylacetonate calculated from the amount of cobalt(II) hydroxide introduced is given for each reaction in Table 4. For example, the yield for reaction 3 is 97% (91 g of product obtained) if it is considered that the product is in the dihydrated form (293.18 g/mol). The theoretical level of cobalt is 20.10%.

TABLE-US-00004 TABLE 4 Yield (% by Reaction weight) 1 94 2 98 3 97