DD152325A1 - PROCESS FOR PREPARING TRIS-HYDROGEN-BIS-OXOMOLYBDAENE (V) -TRIS-PHOSPHATE - Google Patents

Abstract

The subject of the invention is a preparation process for H & ind3! & (MoO) & ind2! (PO & ind4!) & Ind3! XnH & ind2! O (H-MoP) from aqueous oxomolybdenum (V) cations and solutions containing phosphoric acid. H-MoP is e.g. usable for the preparation of heterogeneous catalysts and as inorganic ion exchangers. The aim of the invention is the production of H-MoP while avoiding the oxygen-excluding protective gas atmosphere and in a manner which is more resistant to atmospheric oxygen and thus storage-stable. The object of the invention is the development of a process by means of which it is possible to prepare storage-stable H-MoP from aqueous oxomolybdenum (V) cations and solutions containing phosphoric acid without protective gas. There is a molybdenum (VI) compound in aqueous phosphoric acid (atomic ratio Mo: P between 1: 2 and 1:10) with hydrazinium cations (atomic ratio Mo & expVI!: N & exp-II! Between 1: 0.5 and 1:10) reacted between 60 and 180 degrees C with crystal formation, the crystallization product formed separated from the solution, washed and dried.

Description

Inventor: Berlin, 24.07.1980

253/3040/111 dr. Gerhard Ladwig

-A-

Process for the preparation of tris-hydrogen-bis-oxomolybdenum (V). Tris-phosphate

Field of application of the invention;

The invention relates to a method for producing the hydrogen-oxomolybdän (V) -phosphates of the formula H 1 "(MoO) ₂ (PO.).,] .NH ₂ 0, where the crystal water content nil 0 of the air-dried at room temperature phosphate the value η is approximately equal to 4, from aqueous solution containing 0xomolybdenum (V) cations and phosphoric acid-containing solution, and this phosphate, hereinafter referred to as "H-HoP" for short, is usable, for example

for the preparation of molybdenum (V) and phosphorus (V) heterogeneous catalysts for selective hydrocarbon oxidations and ammoxidations, e.g. according to the patents DD-W? 113,210 and 125,676;

- For the preparation of the also according to DD-WP 113 210 and 125 676 usable group of metal derivatives of H-MoP with the general formula M ^ -KMoO) ₂ (PO.),! MH ₂ 0, with M = 1 metal ion equivalent and with 0 less than or equal to 3 (hereinafter referred to as "M-MoP" for short);

- As an inorganic ion exchanger;

- as a defined, air-stable molybdenum (V) protein chemical for a variety of Porschungs- and development purposes.

Characteristic of the known technical solutions

The phosphate H ₃ [CMoO) ₂ (PO ₄ ) J * nH ₂ O is known (G. LADWIG, Z. Chem. % 398 (1969); Message Bl., Chera Ges., DDR, T6, 77 (1969) Its crystalline water content, nHpO, is variable due to a zeolite-like framework crystal structure of the phosphate, which corresponds approximately to the value η for the phosphate dried in air at room temperature equal to 4 · The phosphate is pale yellow when pure.

Due to the zeolite-like structure of the framework and the presence of acidic hydrogen in the crystal lattice, this phosphate (H-MoP) is an Pest-form inorganic orbital ion exchanger from which ion exchange, including plague neutralization (see DD-WP II3 210 ), optionally corresponding M-Pormen (M-MoP) can be prepared with the above-mentioned general formula of the group of metal derivatives of H-MoP.

With regard to the preparation of the H-MoP itself, only one process principle has hitherto been mentioned in the literature (DD-WP 113 210, page 4, column 2, lines 44 to 51): Concentration of an aqueous MoO ^ ⁺ ions and excess Phosphoric acid, eg according to the atomic ratio Mo: P = 1: 7, containing solution under CO _? Atmosphere - ie in oxygen-exclusive protective gas atmosphere - for the purpose of crystallization of Η. Γ (Μοθ) ρ (ΡΟ.Κ 1 · nH ₂ O followed by filtration, washing and air-drying of the crystals.

A disadvantage of this method is the technically very complicated work under oxygen-exclusive protective gas atmosphere until the presence of K-MoP crystals. It is particularly disadvantageous, however, that in the production of the H-MoP crystals according to the process, batches are produced which are unstable to atmospheric oxygen and thus not stable in storage. Thus, it has been found, until today inexplicably, that in the most painstaking manner produced by the above process

and isolated, although primarily pure, pale yellow H-MoP Curbgen in the normal. Storage in standard chemical bottles, that is, in the presence of air, proved to be unstable: they gradually turned green and then blue due to partial solid state oxygenation by the atmospheric oxygen and the resulting formation of the known Mo / Mo mixed valence interaction color.

Object of the invention

The aim of the invention is the production of H-MoP while avoiding the acid-excluding protective gas atmosphere and in relation to atmospheric oxygen resistant and thus storage-stable form.

T he technical task, which is solved by the invention

The invention has for its object to develop a method by which it is possible from aqueous oxomolybdenum (V) · cations and phosphoric acid-containing solution while avoiding the oxygen-excluding inert gas atmosphere H-MoP produce so that it is resistant to atmospheric oxygen and thus is stable in storage.

Features of the invention

A process for the preparation of tris-hydrogen-bis-oxomolybdenum (V) -tris-phosphate, HT (MoO) ₂ (PO.) -] - nllgO, from aqueous. Oxomolybdenum (V) cations and phosphoric acid-containing solution found. This process is characterized in that a molybdenum (VI) compound in aqueous phosphoric acid at an atomic ratio Mo: P between .1: 2 and 1:10 with hydrazinium cations NpH ₅ ⁺ and / or N ₂ Hg ²⁺ in a Atomic ratio Mo ^VI : ET between 1: 0.5 and 1: 10 at a temperature between 60 and 180 ⁰ C with crystallization, the resulting crystallization product, optionally after thermal evaporation, separated from the solution, washing, if necessary, if necessary, with treatment With

an acidic solution, and dried.

As the molybdenum (VT) compound, sodium molybdate, an ammonium molybdate, preferably ammonium s-heptamolybdate, molybdenum trioxide or its hydrates, dodecamolybdato-phosphoric acid hydrate or their ammonium salt and mixtures of such compounds can be advantageously used. Particularly advantageous is the commercial ammonium hepta molybdate of the formula (EH.) ^ Mo ₇ O ₂ -'4H ₂ O, which in addition to the advantage of ready availability also has the advantage of being well and rapidly soluble in aqueous excess phosphoric acid.

Hydrazinium monochloride, hydrazinium dichloride, hydrazinium phosphate and / or hydrazine hydrate can advantageously be used as hydrazinium cations.

In the context of the invention, the crystallization of the target phosphate (H-MoP) can also be carried out in the presence of previously added H-MoP seed crystals, and it is also possible to use mother liquors or wash waters from previous H-MoP preparation mixtures for subsequent inventive processes Use H-MoP production approaches to save material.

It may happen that, during its crystallization or thereafter, the target phosphate incorporates trace amounts of foreign cations from the solution from which it crystallizes into its crystal lattice; for example 1TH. ⁺ Ions when ammonium molybdate is used as the molybdenum (VI) compound in its preparation. On such a foreign cation content is easy to check qualitatively, and he - if he should interfere with the subsequent use of the phosphate - according to the invention be eliminated by the fact that before the end of washing the separated phosphate, a treatment of the phosphate is carried out with an acidic aqueous solution ,

_ 5 -

As a result of this treatment, the foreign cations which may be present in its crystal lattice are replaced by acidic hydrogen due to the ion exchange of the phosphate, resulting in the pure target phosphate. For this purpose, for example, aqueous solutions of phosphoric acid, hydrochloric acid, hydrazinium dichloride and / or hydrazinium monochloride / hydrochloric acid can be used as the treatment solutions according to the invention. For example, the treatment according to the invention can be carried out by dipping or washing the phosphate on a filter with the treating solution, or, for example, by introducing the phosphate as a filter cake into the treating solution and leaving or suspending it for a while.

It is not always necessary to dry the phosphate at the end of its preparation and workup according to the invention: If it is to be used further immediately, for example to produce (H-MoP) one of its abovementioned metal derivatives M-MoP by ion exchange in an aqueous medium , then the H-MoP can also be used as undried, moist filter cake. The process according to the invention makes it possible to produce the target phosphate HT (MoO) ₂ (PO.),] .N + nPLjO without any use of protective gas in a straightforward manner. The process starts from inexpensive, readily available and chemically insensitive molybdenum compounds and delivers the target phosphate not only in very high yield, but surprisingly in any case in an air-stable and thus storage-stable state. The latter, if one compares with the earlier observations, can not yet be scientifically explained, but may be related to the fact that according to the invention the crystallization of the phosphate is carried out in the presence of hydrazine cations.

embodiments

The invention will be explained in more detail by the following examples, but is not limited to these examples.

example 1

VI,

To a solution of 6.0 g (HH.) GMoI

85 percent Phosphoric acid (H-PO.) In 150 ml solution of 10 g

O and 16.5 ml of O became one

Add ₀ cCIo in 50 ml H ₉ O (Mo: P = 1: 7.15; VT TT

Mo ^va ": lf = 1: 5.6.) The mixed solution was heated in a normal atmosphere in the beaker (under H development blue coloration and finally browning of the solution took place) and then for some time on the water at 80-90 ⁰ C. The precipitate was precipitated, filtered off, treated with a solution of 10 ml of 85% phosphoric acid and 90 ml of H ₂ O, then washed with water and mi / acetone and washed on the filter Air dried at room temperature The pale yellow substance prepared and isolated in this way proved analytically and in terms of its material properties to be H ~ F (MoO) ₂ (PO.) ""] TiH ₉ O with η approximately equal to 4; it contained a qualitatively just detectable trace amount of HH. ⁺ Ions as foreign cations. The yield was 7.4 g, ie 77 % of theory.

Example 2

To a solution of 150 ml H ₉ O, 16.5 ml 85 percent. Phosphorus-

VI acid and 10 g of I HrCL were added 4.9 g Mo 0- (atonic ratios as in Example 1). The mixture was heated to boiling in a beaker initially covered with a watch glass and then uncovered until the molybdenum oxide dissolved completely and crystallization of a sufficient amount of precipitate had taken place. The crystallization product was worked up as in Example 1. This resulted in 2.9 g of air-dry, pure H _ [(MoO) ₂ (PO ^) ~ "| · ηΙΙ ₂ 0, corresponding to a yield of 30 % of theory.

Example 3

There were 65 »5 g Dodekamolybdatophosphorsäure-hydrate (H Μο | 2 ^? 0 ₄₀ · ^ 30Η ₂ 0) dissolved in 750 ml of H ₂ O, and to 162.5 ml 85 percent strength. Phosphoric acid and 100 g of Ii ₂ HgCl ₂ given (atomic ratios as in Example 1). This solution v / urde 5 h to about 85 ⁰ C. and then heated more strongly to the sand bath. This crystallization and concentration of the solution occurred until the formation of a crystal / liquid paste, which finally had a temperature of 15O ⁰ C showed. The cooled paste was then treated with 500 ml H ₂ O and the crystallization product was worked up as in Example 1. This resulted in 91.2 g of air-dry, pure H ^ F (MoO) ₂ (PO ₄ ) - "J TLhLO, corresponding to a yield of about 95 % of theory.

Examples 4, and 5

It became as in Example 1 of 6.0. g ΗΗ, heptamolybdate

VI II and also the atomic ratio Mo : Ή ~ = 1: 5 »6 maintained. However, the amount of phosphoric acid used was reduced according to the atomic ratio Mo: P = 1: 4 »O5 (Example 4) or 1: 5> 08 (Example 5), and the batch solution was first heated on the water bath and then heated to 16O ° C , The resulting paste was washed with 200 ml of H 2 O and 20 ml of 85 percent strength by weight. Phosphoric ver sets and stirred and then worked up the crystallization product as in Example 1. Yield of B7I. ⁺ P traces (ΜοΟ) ρ (0.) Τ j'nlipO: greater than 70 % (Example 4) or greater than 80 % (Example 5).

Example 6

Vl,

! 120 g (iHJrMo ^"x 0 _o percent strength .'4Ho0, 1500 ml H ₀ O, 330 ml 85 H and 65 g H ₂ H ₅ Cl (Mo: P = 1: 7.15; Mo-N. = 1. : 2.8) were converted to a crystal / liquid slurry by final heating to ~ 140 ° C. The slurry was filtered to give the crystallization product after short incubation

treated with water by stirring with a solution of 51 g of NpHgp in 500 ml HpO, then filtered, washed with water and with acetone and dried in air. This gave 182 g of air-dry, pure, IT-free H _ [(MoO) p (PO.) ^ J · ηΗρΟ, corresponding to a yield of 95 % d. Th.

Examples 7 and 8

The procedure was analogous to Example 6. The atomic ratio Mo: P = 1: 7 »15 was maintained. However, it was assumed that a) 240 g (ITH) r Mo ₇ O * 4H _o 0, b) the employed ._ 4 ο ί 24 ^ VT -TT

H ₂ H ₅ Cl corresponding to the atomic ratio Mo: 1T = 1: 2.0

(Example 7) or 1: 1.0 (Example 8) reduced and c) the treatment of the crystallization product not with a using KgHgCl ₂ , but under 1: 1 stb * chiometric use of ITpH ₁ -Cl and hydrochloric acid produced Solution made. The result was air-dry, pure target product 317 g (Example 7) or 347 g (Example 8) H ("(MoO) ₂ (PO ₄ ) J · ηΗ ₂ 0, corresponding to a yield _{V of} 83 % and 91 %, respectively .

The (pale yellow) H _ [(MoO) ₂ (PO.) -] * Dl-I ₂ O produced according to all Examples 1 to 8 above proved to be indefinitely stable in an air-dry state at room temperature with normal storage in chemical bottles compared to aerated acid.

Example 9

The preparation and processing of H ₃ [(MoO) ₂ (PO.) - ItLH ₂ O was repeated according to Example 8, except that the target crystallization product was not treated with an HpH ₁ -Cl / HCl solution and finally was air-dried, but as a wet cake in a HaIICO - transferred solution, and therein by ileutralisations ion exchange in the metal derivative ITa ₀ H _n r J (MoO) ₀ (PO,) ~ 1 × _ιήΗ ο was converted 0th

Claims (1)

223 004 Erf in d tmp; g to pr uc h 1. A process for the preparation of tris-hydrogen-bis-oxomolybdenum (V) tris-phosphate, H [(MoO) ₂ (PO.) ₃ ] · ηΗ ₂ Ο, from aqueous Ox ornolybdän (V) cations and phosphoric acid-containing Solution, characterized in that a molybdenum (VI) - 'compound in aqueous phosphoric acid at an atomic ratio Mo: P between 1: 2 and 1:10 with hydrazinium cations W ₀ H _n and / or U ₀ Hc ^{2+ b with} an atomic ratio Mo ^VI : ET ¹¹ 2 5 2 b between 1: 0.5 and 1:10 at a temperature between 60 and 180 ⁰ C to crystallize, the resulting crystallization product, optionally after thermal evaporation, separated from the solution, washed, optionally with treatment with an acidic solution, and dried , A process according to item 1, characterized in that the lilybdenum (VI) compound used is IT sodium molybdate, an ammonium molybdate, preferably ammonium heptamolybdate, molybdenum trioxide or its hydrates, dodecamolybdato-phosphoric acid hydrate or its ammonium salt, and mixtures of such compounds. Process according to item 1, characterized in that hydrazine monochloride, hydrazinium dichloride, hydrazinium phosphate and / or hydrazine hydrate are used as hydrazinium cations. AO
-S 4 · Method according to item 1, characterized in that the acidic treatment solution used is an aqueous solution of phosphoric acid, hydrochloric acid, hydrazinium dichloride and / or hydrazinium monochloride in hydrochloric acid.