DE1965176A1 - Process for the production of molybdenum and iron containing gels and their application - Google Patents

Description

The present invention relates to a process for the production of gel-like inorganic, solid and transparent Complexes of iron (III) ions and molybdate ions. The invention also relates to the use of these gels as optical filters and as precursors of a family of mixed oxides between the iron oxides and the molybdenum oxides.

The invention also relates to a method of application of certain Gels as precursors of oxidation catalysts during oxidation from primary alcohols to aldehydes and especially from methanol to formaldehyde.

Finally, the invention also relates to a method which uses these catalysts and to the

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drive won products.

It is well known in the art that the reaction between a soluble ferric salt and a soluble molybdate to precipitate and form a substance of the approximate formula Fe ₃ O ₅ , 3-4 MoO ₅ , ) f H ₃ O (xf <10), which in its natural state is known as ferrimolybdite and in which the atomic ratio Mo / Fe is between 1.5 and 1.95.

The composition of the artificial precipitation varies depending on the temperature. at which the precipitation reaction is carried out and depending on the molecular ratio Molybdenum / iron in the raw materials. At normal temperature, the Mo / Fe atomic ratio is between 1.5 and 1.7, these narrow limits apparently being a consequence of the crystalline structure of the compounds formed.

If one solutions of a known type from a soluble iron (III) salt and a soluble molybdate in which the atomic ratios Mo / Fe are below 1.5 or above 2, with one another lets react, the dejected composition has the tendency to emerge from the overall composition of the two reacting Remove solutions and feel the composition of hydrated Approach ferric molybdate or ferric molybdite. It is also known that a precipitate has a heterogeneity in the Passage of the solution through the precipitated mass is caused, so that the composition changes in the course of the precipitation.

It has now been found that it is possible to allow a solution of a soluble iron (III) salt and a solution of a soluble molybdate to react with one another in such a way that the precipitation is both partial and reversible in nature * the pasty mass ultimately obtained transforms itself more or less rapidly into an opaque substance and then into a transparent, hard and brittle substance. ^; v

00 98 34/1943 ^ "

The gels obtained by the process according to the invention are characterized by their transparency and their crystalline formlessness, which makes it possible to guarantee their homogeneity on a molecular scale. They can be obtained in a wide range of compositions, with iron and molybdenum being present in an atomic ratio of Mo / Fe between 0.4 and 5. It is also possible to partially remove the iron (III) ion in these substances by metal ions such as chromium, cobalt, nickel, manganese and also by scandium, yttrium and certain rare earth ions (elements with atomic numbers 57 to 71 including) and also to partially substitute the molybdenum ion with metal ions such as tungsten, ohrom, vanadium, uranium and manganese. Each of these substitutions can relate to 0 to 50 % of the iron atoms or molybdenum atoms involved in the conversion.

In the following, M denotes the element or elements that partially denotes iron and N denotes the element or elements, which partially replace the molybdenum.

These gels are prepared from aqueous solutions known per se of the reactants involved in the reaction. One uses generally those solutions in which the molybdenum and the other metals N are in anionic form and in one Total concentration between 0.1 and 2.5 gram atom per liter.

In the case of the sole use of molybdenum, it corresponds to a concentration of 72 to 360 g of molybdic anhydride MoO, per liter.

Any soluble salt in which molybdenum is anionic can be used to introduce molybdenum into these solutions Form is located, with the exception of the molybdates of alkali metals, such as lithium, sodium, potassium, which are generally a simple Favor precipitation and in the best case too opaque and hetero-

009834/1943 ~ ⁴ ~

lead to genetic gels.

It is therefore preferred to use ammonium salts, for example (Molybdate, heptamolybdate or paramolybdate, also dodecamolybdate), ammonia being added if necessary.

In the case of tungsten, chromium and manganese, the preferred masses are used anionic salts, i.e. salts in which the metals just mentioned are in the anionic part, preferably Ammonium salts such as tungstates, metatungstates or paratungstates of ammonium, chromates or bichromates of ammonium and manganates or permanganates of ammonium.

In the case of uranium and vanadium, the use of ammonium uranates, ammonium vanadates, and ammonium metavanadates not very comfortable; these elements are preferably introduced in the form of the uranyl and vanadyl cations, for example in Form of uranyin nitrate and vanadyl oxalate. These metals will generally introduced in the form of solutions which contain the molybdenum and optionally also ammonia; it but it is also possible to introduce the former into the solution containing iron before the two solutions are mixed. In the special case in which the gels are mixed with vanadyl ion, it is preferred to use the solution in a variable amount ) to be treated with an oxidizing substance, for example with hydrogen peroxide in an aqueous solution.

The metals present in cationic form (iron, cobalt, nickel, manganese, chromium, rare earths, etc.) can be introduced in the form of soluble salts, such as nitrate, chloride, acetate, formate, carbonate, bromide, oxalate or sulfate . However, it is preferred to use the nitrates which allow the gels to be obtained under the best conditions. The concentrations of the solutions are between 0> 3 g-ions of metal per liter and the degree of saturation} these solutions can, if necessary, be treated with a mineral acid,

009834/1943 -5-

- sheet 5 -

such as with nitric acid, sulfuric acid, formic acid, Perchloric acid, hydrochloric acid, hydrofluoric acid or any other strong acid.

It should also be noted that it is not possible to Introduce iron in the form of salts of divalent iron, since their reducing power in the solution is such that at The presence of, for example, an aqueous solution of ammonium molybdate caused the precipitation of "molybdenum blue" which makes the subsequent gel formation reaction very difficult.

According to a preferred embodiment of the process according to the invention, the solution, which contains the molybdenum and optionally other metals of the type listed above in anionic form (solution A), is placed in a trough and stirred vigorously using, for example, a paddle stirrer at 400 to 1500 revolutions per minute and in particular with 600 to 1100 revolutions per minute or another stirring system used, which makes it possible to generate a uniform turbulence in the liquid; turbines, mixers, oscillation stirrers, vibration stirrers or magnetic stirrers, which may be mentioned by way of example, can be used. The temperature of the solution is set to a value between the congelling of the solution and 30 ° C. and in particular between ⁰ ° C. and 15 ° C. The solution which contains the metals in cationic form (solution B), the temperature of which has previously been set within the same limits, is added to this solution.

Solution A can also be poured into solution B. Furthermore, both solution A and solution B can optionally be mixed with a soluble mineral salt of the ammonium chlorate, ammonium perchlorate or ammonium nitrate type before mixing, and also the mixture A + B.

After mixing solution A and B described above

009834/1943 _ ₆ _

three different types of reactions can take place, depending on the atomic ratio Mo / Fe in the mixture of solutions A and B, depending on the concentration of the solutions present, their pH value, their temperature and finally depending on the The rate at which one solution was added to the other. The first stage is always the formation of a colloidal suspension and the final stage in the formation of a clear, hard and brittle gel.

The first of these three types of reaction is then observed, when preparing gels which contain an atomic ratio of Mo / Fe between 0.4 and 1.5; if you look at these manufacturing methods If solutions with concentrations between 0.5 and 2 M are used, one first observes that a precipitate forms, which dissolves again very quickly and results in a transparent and slightly opalescent solution. This solution shows a viscosity increasing with time and temperature; it finally changes into an elastic and transparent one Gel around. This gel loses its elasticity when the Mo / Fe ratio exceeds 1.5, the gel then becomes hard and brittle.

It should be emphasized that with these atomic ratios the use of solutions with concentrations above 2 M will result in a reaction of the type described below.

The second type of reaction is observed when gels are prepared which have an atomic ratio of Mo / Fe between 1.5 and 5, the solutions having concentrations between 0.5 and 2 M; In this case, when the two solutions are mixed, in particular the simultaneous co-precipitation of ferric molybdite and molybdic anhydride MoO takes place. If the stirring of the pasty suspension obtained is continued, no spontaneous redissolution takes place as in the first type of reaction; the pasty Maese first transformed into an opaque hard and brittle, and then in a transparent substance which

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is also hard and brittle and which, with an obvious Mo / Fe ratio, is similar to that which is found in the first Response type received ^ um.

The gel obtained in this way has an intense green color, which may be slightly modified by the presence of other contingency elements. This gel is also crystallographically amorphous and contains in complex form the ions that are contained in the starting solutions, as well as further Water of crystallization of the salts and water that was added during the preparation of the solutions.

If the Mo / Fe ratio in the gels is above 1.6, those produced by reactions of the second type contain Gels after gel formation, solid particles made of molybdenum trioxide ) Hydrate.

It is possible to avoid this disadvantage by using solutions, the concentrations of which are preferably between 1 and 2.5 M is and by the solution containing the iron (III) ions and any other cations that may be present, slowly poured into the solution containing the molybdate ions and the other anions, the latter possibly being done beforehand cools to a temperature between the exact con-gel formation temperature and 15 ° 0. The opaque, hard one obtained in this way and the brittle mass is finally transformed into a transparent gel that no longer contains any solid particles in suspension.

The third type of reaction is found in the case in which dilute solutions (concentrations 0.5 M) are used, the Mo / Fe ratios being between 0.4 and 5. It then forms a colloidal suspension that does not sediment i he t and is not transformed into an opaque, hard and brittle gel, as was the case above.

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This colloidal suspension can, if it is quickly heated to the boiling point, turn into a homogeneous paste-like mass by evaporation, which is heated in a heating cabinet to a temperature between 40 and 120 ⁰ G and in particular to a ^{temperature of 50 to 90 0} O transformed into a transparent, hard and brittle gel, which is similar to the one obtained according to the two methods described above. It is to be noted that if the atomic ratio Mo / Fe in this product is above 2.5? the gel obtained contains some particles that did not react.

Those produced by one of the three types of reactions described Clear gels can be dehydrated, for example in a heating cabinet or with the help of another suitable device, within a period of 6 or more hours and at a temperature of 40 to 150 ° C. Their water content can thereby be reduced to a value of 0 to 10 percent by weight be reduced. The gels are transformed into new gels of brown-red color, which are also crystallographically amorphous and are transparent in the visible range and in the near infrared range.

In the above-mentioned gels, the Mo / Fe ratio can be arbitrarily if necessary, can be replaced by Mo / Fe + M, Mo + N / Pe or Mo + N / Fe + M.

The gels obtained in this way can advantageously be used as optical filters before or after their dehydration.

As an example, the accompanying FIG. 1 shows the curve of the optical transmittance of a gel in which the atomic ratio Mo / Fe is 1.5 and which was produced according to the present invention according to the first type of reaction of the type described above.

This gel lets the light rays in a wavelength range from 0.4 to 1.3 / u through.

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Sheet 9 -

Figure II shows the graph of the optical transmittance of the same gel after dehydration in a drying cabinet ^ within 24 hours at 60 ⁰ G. This gel makes the light beams in a range from 0.6 to 1.9 / & therethrough.

FIG. II also shows the curve of the optical transmittance of a gel which has an atomic ratio Mo / Fe of 1 and which has been dehydrated according to an analogous procedure. This latter gel leaves the light rays in a wavelength range of 0.55 to 2.5 M therethrough.

A second application consists in the thermal decomposition of the novel compounds obtained after the dehydrogenation Gels, this thermal decomposition being carried out in an oxidizing, neutral or reducing atmosphere and one obtains a family of mixed oxides from molybdenum oxides and iron oxides by this thermal decomposition.

Examples 1 to 8 illustrate these two first embodiments of the invention.

A third way of using these gels is to disintegrate them according to certain fixed modalities, whereby one an oxidation catalyst for the conversion of primary alcohols to aldehydes and in particular of methanol to formaldehyde , wins.

Oxidation catalysts are already known for the oxidative conversion of methanol to formaldehyde, which consist of oxides of iron and molybdenum and which are generally called iron molybdates; These are usually produced by reacting an iron (III) salt, which is soluble in water, with a likewise water-soluble molybdate, the reaction leading to precipitation and the reaction usually being carried out at a temperature of 40 to 90 ^° C leads, as well as starting from dilute solutions (0.02 to 0.5 M »molar). Bas after washing

009834/1943

and drying, precipitate product has a molar ratio MoO ^ / Fe ^ O, on, which is generally between 3 and 8 lies.

The composition of these catalysts is essentially contained within the limits in which the phases MoO ₂ and (MoO ₂ ,) exist simultaneously.

They can be mixed with oxides such as GoO, ITiO, MnO, Gr ₂ O-, GeOp, which are added in a ratio of 0.05 to 1 mol of oxide per

Mol Fe O, introduces.
2 3

In general, they are not self-supporting catalysts, but about those that are deposited on different supports, such as "for example on steel balls or Carborundum spheres, carriers that are known per se.

The manufacturing process of these catalysts brings a heterogeneity, be it Clunischer, physical or mechanical, in the passage of the solution through the catalytic mass.

In the most common manufacturing process, for example, the composition of the precipitate obtained moves away from that of the solution and approaches that of ferric molybdate hydrate or ferric molybdite (Fe ₃ O ₅ , 3 to 4-MoO ,, tf "HpQ), which makes it necessary to maintain molar ratios MoO ^ / Fe ^ O, in the initial reactants, which are much greater than in the product that is formed at the beginning of their precipitation reaction structural and textural aspects, which change in the course of the precipitation reaction.On the other hand, it contains potentially unbound iron oxide, which, due to its strong tendency to cause total combustion of the reactant, leads to a reduction in the activity and selectivity of the catalyst.

009834/1943 -11-

BAO

Another cause of this Hefcerogesiität "ordered in äex- Hinsufügung of additions to precipitate", for example, iron Crp O _5, or GoO. If you add ghromsal or cobalt salζ to the solution of the iron salt and cause a precipitation, each salt with the molybdate ions precipitates out at its own speed (so-called co-precipitation). If one mixes the precipitate (F-8p O ₃ , - y MoO ^), which one has partly received, with the precipitate CoMoO ^, HpO, which one has received on the other hand, then kneaded and calcined, this reaction takes place in the solid state between the two substances never complete «This heterogeneity results in a low activity and selectivity of the catalyst.

It generally follows from this that the catalysts of the prior art bring about a molar conversion of methanol to formaldehyde which is practically complete (99 %), but the yields of formaldehyde are only 90 to 91%. In the best case, the maximum yields are more than 95%

It has now surprisingly been found that, according to the present invention, it is possible to produce catalysts which are both more active and more selective than all the catalysts belonging to the prior art, working according to an analogous procedure, but from very special, adapted, homogeneous mixtures Iron molybdate phases and molybdenum oxide phases of the general formula Fe ₂ (MoO ^) ,, X "MoO-, where £ varies between 0 and 7, and in this formula the iron and molybdenum can be substituted by other atoms in the manner shown above, (partial substitution).

the
The homogeneity of these products is achieved in that concentrated solutions of metal salts are preferably mixed with vigorous stirring at a temperature between the temperature of the congel formation . 20 ° C and preferably between 0 and 15 ° C can react with each other and then the resulting

»12-

009834/1943

- sheet 12 -

The pasty mass first turns into an opaque, solid mass and finally into a transparent, hard and brittle substance can convert.

In addition, foreign ions introduced by the reactants are allowed to enter the catalyst Foreign ions such as nitrate ions or ammonium ions.

One generally proceeds in a way that is theirs is analogous to that described in the second type of reaction resulting in a gel.

The other two types of reactions leading to a gel are slightly more expensive and less convenient methods, namely with regard to the amount of water that must be removed by evaporation before thermal decomposition, wherein this thermal decomposition leads to the catalyst; the latter is also somewhat more fragile in the case just described mechanical terms; it is therefore preferred to carry out the procedure described above as the second method.

The metals introduced as cations (iron, cobalt, nickel, chromium, manganese, rare earths) that have a Playing role are introduced in the form of nitrate solutions, which have a gram atom number of metal per liter of more than 1 and preferably between 1.5 and 2.5.

In general, the solution containing the molybdenum in anionic form is placed in a trough in a manner known per se Way to a temperature of the beginning con-gelation of the solution and 20 ° C and mostly to a temperature between 0 and Cooled 15 ° C, in those cases in which solutions are used that contain 1.5 to 2.5 gram atom of molybdenum per liter contain.

The solution, which contains molybdenum and possibly other metals in the anionic state, is then violent

009834/1943 -15-

Stir, using, for example, a plate stirrer with a speed of between 400 and 1500 revolutions per minute and in particular from 600 to 1100 revolutions per minute; you can do any other use a stirring system known per se, which makes it possible to maintain an equivalent turbulence in the liquid, For example, a turbine, a mixer, an oscillation stirrer, a vibration stirrer or a magnetic stirrer .

The solution, which contains the iron and optionally other metals in cationic form, is added in a controlled throughput to the solution which contains the ammonium molybdate, while maintaining a rate which is generally below 6300 ml per liter and hour and preferably between 200 and 3,000 ml per liter per hour. The temperature of the mixture is adjusted to a value between the temperature of the Con-gelation and 20 ⁰ C and preferably between 0 and 15 ° C. Occasionally, when all of the nitrate solution has not yet been added, a thickening of the resulting solution is observed, which can be achieved by adding a small amount of water or by accelerating the addition of the nitrate solution (this can be increased to 8000 ml per liter per hour) in the general can limit.

The suspension obtained in this way thickens within a period of time which is variable and which depends on the concentration of the reactants, on the temperature at the time of the reaction and the temperature afterwards, on the type and concentration of the additives added and on the rate of reheating of the product depends. This period of time varies from 1 to 60 minutes starting from the end of the addition of the reactants.

If it is no longer mechanically possible to use the suspension stir, so let them rest; it then hardens very quickly

009834/1943

■ and turns into a yellow-green product that has more or ■ is less opaque, hard and brittle.

Before this hardening takes place, it is possible in a manner known per se, for example by. Extrusion, spinning or Tableting to bring the product into any desired shape. The product can also be cast on a plate and after hardening, cut into pieces of the desired dimensions.

This product is then heated slowly to a temperature between 15 and 100 ⁰ G, and more particularly to such P between 25 and 60 ⁰ C. It transforms itself into a translucent gel with a more "or less intense green coloration, which is characterized by an optical light transmission curve that is analogous to that shown in Figure 1. The coloration of the product can be easily modified by the fact that the ( above) contingent additives are present; this gel, like the product from which it was created, is hard and brittle.

The duration of the conversion of the opaque product to gel is a function of the molybdenum content of the product, the content of additives and their nature, the concentration of the reactants before the reaction in water, and the temperature; this conversion can vary between a duration of 5 hours at 20 to 30 ⁰ O and a few minutes at 50 to 60 ⁰ O.

The gel derived from this reaction is then 6 hours or more, and usually 24 to 72 hours dried at a temperature between 40 and 150 ° C and in particular between 50 and 90 ° 0 in a drying cabinet long. The product is slowly dehydrated , its water content dropping from 60 to 80% by weight to one from 0 to 10 % by weight, and the conversion into a new gel takes place.

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»Sheet 15 -

finds that is comparable to that already described above and which is characterized by an optical light transmission curve analogous to that of FIG is. This new gel, which is also crystallographically amorphous, like the product from which it comes, is visible and transparent in the neighboring infrared range and brown-red in color. It sometimes has a surface with opaque fluorescence due to its ammonium nitrate content. After all, this new gel is hygroscopic, with one low rehydration in air keeps it its original Resumes green color; this new gel is called a "precatalyst".

You can also use this pre-catalyst by so-called lyophilization the paste-like suspension obtained before it hardens or also by lyophilizing gel parts. The water present in the product is then removed in vacuo at a low temperature as a result of evaporation.

The primary catalytic converter has the advantage of being easy to transport; its thermal decomposition can occur within a variable period of time after its production can be carried out without affecting the properties of the resulting catalyst are subject to modification.

* ■

The thermal decomposition of the pre-catalyst is carried out at a temperature between 300 and 500 ° C and in particular between 350 and 4-7O ⁰ G. It is possible to introduce the pre-catalyst directly to a furnace with variable temperature (350 to ⁰ 4-70 G) or to carry out calcination by incrementally increasing the temperature up to a value between 350 and 4-7O ⁰ G. This operation can be carried out directly in the catalytic reactor in which the catalyst is tested; the heating can also be carried out in any other device that allows sufficient thermal compensation »

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The thermal decomposition is carried out within a variable period of time depending on the type of heater used. For example, when working in a plague bed oven, it is preferable to choose a time of less than 6 hours and especially one from 1 to 5 hours.

The temperature that is measured directly in the pre-catalytic converter in the course of the decomposition should not exceed the value of ^ OO ⁰ G; Calcination temperatures that go beyond this can cause the catalyst to be deactivated later.

The catalyst obtained in this way is a pesticide with greenish-yellow to greenish color in the absence of additives; its color varies in the case of the content Additives depending on their type. Its mechanical resistance is good, its specific surface is between 0.5 and

20 m per gram; the best results are obtained when

ρ the surface of the catalysts between 4 and 12 m per gram amounts to.

The catalyst can be diluted with catalytically inert substances and have a suitably selected particle size. the Volume proportion of catalyst / thinner + catalyst can vary between 0.1 and 1. The granulometry of the thinner is advantageously chosen in a range which is adjacent to the particle size of the catalyst.

The inert diluents usually used have variable shapes or designs and can, for example, as spheres, Cylinders or rings are used. You can, for example, made of ceramic material, aluminum oxide, Silicon dioxide, silicoaluminates, also consist of glasses or silicon carbide.

The diluent particles can be mixed with the catalyst particles, they can also be in one or more beds arranged above or below the catalyst particles

00983A / 19A3 '-17-

- sheet 17 -

or also be interposed in a catalyst bed; in general, they are upstream of the catalyst bed tet or intermediary.

The suitable diluents, which are arranged in a certain spatial relationship to the catalyst bed, allow an improvement in thermal compensation in the catalytic converter. In addition, they allow the phenomena of abrasion or to limit the attrition of the catalytic bed and thus losses of catalyst charge in this bed.

The oxidation of methanol to formaldehyde is carried out in such a way that a mixture of methanol vapor and the gas containing the molecular oxygen is passed over the catalytic bed at any pressure, preferably at about atmospheric pressure, the catalytic bed at a temperature of 250 to 4 50 ⁰ C and preferably from 3OO to 4-00 ° 0 is preheated. The gas accompanying the oxygen can consist of nitrogen or any other inert gas to which gas of the type of water vapor or carbon dioxide gas has been added, if necessary. The proportions of inert gas and oxygen are indifferent; their selection depends primarily on the risk of explosion of the mixture with the methanol vapor. Air can advantageously be used instead of the nitrogen-oxygen mixture.

The proportions generally observed for the gaseous mixture of air and methanol vary between 3 and 15 % and in particular between 5 and 7 percent by volume of methanol / air; the mixture of methanol and air passes over the catalytic bed at an hourly volume rate, expressed in liters of gas mixture at normal pressure and normal temperature per liter of catalyst and per hour, which is between 3600 and 72000 and preferably between 24000 and 36000. This embodiment of the invention is further described in the following further below Examples 9 to 27th

00983 4/19 4 3 - ¹⁸ "

- sheet 18 -

The essence of the present invention will now be further elucidated by way of non-limiting examples. The values given in the accompanying figures for the optical light transmission and the percentages as a function of the wavelengths are expressed in / u.

Example 1;

500 ml of an aqueous solution 1 M / 7 (176.6 g per liter) of ammonium paramolybdate tetrahydrate are treated at a temperature of 20 ^° C. and with vigorous stirring with 500 ml of an aqueous 1 M (1 molar) solution (404 g per liter ) an : iron ( III) nitrate. ^ nonahydrate »aas also has a temperature of 20 ° G ', whereby the second-mentioned solution is poured into the first solution within 2 minutes. A colloidal suspension is formed, which is inside 2 minutes dissolves and converts to a transparent elastic gel with intense green color within 5 minutes.

This gel is dried in a drying cabinet at about 70 ° G for 24 hours; it creates a transparent product of brown-red color that is hard and brittle. The optical transmittance curve of this product is measured (curve b), with a Bedkmann-DK-2 apparatus is from 0.22 to 2.5 and Ai is abgebil- on the accompanying Figure II W det (sensitivity 20, and thickness of the Scale 1 mm).

The thermal decomposition of this product stream within 15 minutes in a nitrogen stream, and then carried out within 3 hours at a temperature of about 600 ⁰ G in a hydrogen. Selectively obtaining a mixed oxide of the formula FeMoO ^, whose crystalline structure in the reference Hunter (W), Rahmel (A) and Becker (K), Archives described for the iron and steel industry £ 1959 pages 435-439.

Example 2;

Treat 250 ml of an aqueous solution 1 M / 7 (1? 6.6 g /

009834/1943 -19-

Liter) of ammonium paramolybdate tetrahydrate, which is obtained under a violent Keep stirring at normal temperature, with 500 ml of one 1 M (404 g / liter) aqueous solution of iron (III) nitrate nonahydrate, which is also at normal temperature, the latter solution being poured into the former within 2 minutes. The resulting precipitate dissolves again as in example 1, whereby a mass is formed which turns into a brownish, elastic and transparent one Gel transformed.

This gel is dried for 24 hours in a drying cabinet at a temperature of about 70 ° C., resulting in a transparent gel The result is a product with a red color, which is hard and brittle.

The thermal decomposition of this product is first carried out for 15 minutes under a nitrogen stream and then for 4 hours under a hydrogen stream at a temperature of about 700 ⁰ C. The radiocrystalline graphic examination of this new substance shows that it is a phase with a spinel structure (Fe ₂ MoO ^), which is also described in the literature cited in Example 1. This mixed oxide is magnetic.

example 3 '

A gel-forming substance of the mixed phases with an atomic ratio Mo / Fe = 1.5 is produced as follows:

600 ml of an aqueous solution of 176.6 g / liter (1 M / 7) ammonium paramolybdate tetrahydrate, which is vigorously stirred at room temperature, are mixed with 400 ml of a 1 M (= 1 molar) aqueous solution (404 g / liter) of iron (III) nitrate nonahydrate, which is also at room temperature, is added, the second-mentioned solution being added to the first-mentioned solution within 2 minutes. The resulting colloidal suspension dissolves again and performs innerfealb of 15 minutes at 20 ⁰ C to a transparent gel, which is intensely colored green,

009834/194 3 ~ ² ° ~

The optical transmittance curve of this gel of a width of 5 mm became 0.22 and .2 with a Beckmann DK 2 apparatus 2.5 / u determines what corresponds to the curve shown in FIG (Sensitivity 20 and thickness of the scale 1 mm).

The transparent green gel is dried in a drying cabinet ^{at 60 ° C. within 48 hours.} This creates a transparent product, brown-red in color, which is hard and brittle. The optical transmittance test of a plate made of this gel with a thickness of 1 mm, using a Beckmann DK 2 apparatus, showed a light transmittance between 0.22 and 2.5 Mi which corresponds to curve a in the enclosed FIG. II (sensitivity 20 and thickness of Scale 1 mm).

The thermal decomposition of this new product, which was carried out in a stream of air within A hours at 600 ^° C., leads to the Fe ₂ (MoO ^,) phase, the crystalline structure of which has also already been described in the literature cited in Example 1.

Example 4-:

The obtained according to Example 3 brown-red transparent product is decomposed within 15 minutes in a nitrogen stream and then heated 4- hours under a gas mixture of nitrogen and hydrogen in a volume ratio of 50:50 at a temperature of about 600 ⁰ C. The hexagonal phase Fe ₂ Mo ^ Og is obtained, which is described in the Mc. Caroll (WH), Ward (E) and Katz (L) J.Am.Chem. Soc. 1956 £ 8 pages 2909-10 is described.

Example 5 »

In _{this example, the Fe 0} Mo, 0 _Q phase is produced using trivalent iron in chloride form:

To 300 ml of a 2M / 7 aqueous solution (353.2 g / liter) of

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- sheet 21 -

Ammonium paramolybdate tetrahydrate, which is kept at a temperature of about 10 ^° C. with simultaneous vigorous stirring, is added within JO minutes about 200 ml of a 2M aqueous solution (540.6 g / liter) of iron (III) chloride hexahydrate, which is then added has previously brought to a temperature of about 15 ^° C.

At the end of the addition of the reactants, a pasty suspension is obtained which is heated to a temperature of about 15 ° C., the mass taking on an opaque appearance with a yellow-greenish color; Through a ripening process within 5 hours at 50 ^° C., this product is transformed into a translucent gel of green color. After drying for 48 hours at 75 ° C in a drying oven, this gel turns into a transparent brown-red colored product, which has a yellowish powder on its surface, which consists mainly of ammonium chloride. From a mechanical point of view, this product shows very mediocre behavior.

The breakdown of this product is carried out by the method described in Example 4, in an oven at 600 ⁰ C. This gives a product without mechanical strength, which is partly composed of the hexagonal phase Fe ^ Mo, -O ^ g; it also contains molybdenum dioxide MoOp and the phase. FeMoO ₂ . , Substances all of which are described in the literature cited in Example 1.

Example 6:

Treating 500 mL of a 2.5 M / 7 aqueous solution (441.5 g / l) of Ammoniumparamolybdattetrahydrat that are considered at a temperature below 20 ⁰ C and with vigorous stirring, with 500 ml of a 2.5 M aqueous solution (1010 g / l) nitrate nonahydrate of iron (III) · has also maintained at a temperature below 20 ⁰ C, wherein the second-mentioned solution is poured within 30 minutes in the former. A sand-yellow colored suspension is formed which, when recovered,

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- sheet 22 -

warm to a temperature of about 20 ° G transformed into a mass.

This mass changes spontaneously within about an hour into a green, transparent, hard and brittle one Product which is then dehydrated in a drying cabinet at 70 ° C. for 24 hours. This gives you a new, transparent one Product with a brown-red color which is comparable to the product obtained according to Example 1.

This product, produced as just described, is thermally decomposed as shown in Example 1, whereby the Mixed oxide of the formula FeMoO ^, forms.

Example 7

1000 ml of a 0.5 M / 7 aqueous solution (88.3 g / l) of ammonium ^{paramolybdate tetrahydrate, which has been kept at a temperature below 20 0} O and with vigorous stirring, is treated with 1000 ml of a 0.5 M aqueous solution ( 202 g / l) of iron (III) nitrate nonahydrate, which has also been kept at a temperature below 20 ° 0, the "second-mentioned solution being poured into the first-mentioned within 30 minutes. A colloidal suspension is formed which progressively transforms into an opaque and pasty mass within 4 hours when heated to a temperature of about 90 ° 0. This opaque paste-like mass is then heated in a drying cabinet to a temperature of about 70 ° C, where it heats up within 48 hours converted into a transparent brown-red colored product which is comparable to that obtained according to Examples 1 to 6.

This product is also thermally decomposed as described in Example 1, the mixed oxide FeMoO ^ being formed.

Example 8:

This example shows the production of a mixed oxide

009834/1943

systems with partial cobalt substitution of the formula Fe ₂ _ _x Go _x (Mo0 ₄ ) ₅ , 0.4 MoO _$ with x = 0.19.

250 ml of a 2 M / 7 solution (353 ₅ 2 g / l) of ammonium paramolybdate tetrahydrate, which is kept at a temperature of about 10 ⁰ O and with vigorous stirring, were decomposed with a solution consisting of 133 ml of a 2 M solution of Iron (III) nitrate nonahydrate (808 g / l) and 14 ml (20 ° G) of a 2 M solution (582 g / l) of cobalt nitrate hexahydrate. This solution had previously been cooled to a temperature below 20 ° C. and then poured into the former solution at a relative rate of about 1200 ml per liter per hour.

A yellow-pink colored pasty suspension was formed, which spontaneously turned into a hard mass of the same color and then transformed into a clear gel that is yellow - pink in color.

This gel was dried for 48 hours in a drying oven at 60 ⁰ C, where it turns into a transparent gel of intense red color, then 4 hours at 600 ° C is thermally decomposed.

A product of sand-yellow color is obtained; radiocrystallographic analysis of this product shows that it is indeed the phase Fe ₀ Go (MoO ^,), whose X-ray diagram is comparable to that of Feg (MoO ^), with a slight variation in the neighboring parameters ; one also observes a few lines that are not very intense and correspond to the diagram of the molybdic anhydride MoO.

Example 9:

To 500 ml of an aqueous solution of 353.2 g / l (2M / 7) of ammonium paramolybdate tetrahydrate, which is previously brought to a temperature cooled from 10 to 15 ° C and kept stirring at the same time, were at a relative speed of

-24-009834 / 1943

1600 ml per liter per hour 313 ml of an aqueous solution of 808 g / l (2 M) to iron (III) nitrate nonahydrate a temperature of 15 "to 25 ⁰ C added.

The resulting suspension was kept at a temperature of about 10 ° C., during which it turned into a mass. The spontaneous transformations to which this composition underwent resulted in a green colored, transparent, hard and brittle product in a period of 15 to 25 ° C, which was then dehydrated for three days in a drying cabinet at a temperature of 60 to 70 ° 0 . This gave a new product with a brownish-red color, which is transparent, hard and brittle, and which is in a variable period of time at temperatures between 4-00 and 4-50 ⁰ O under a gentle stream of air within 3 to 5 hours decomposed in an oven.

This gave a yellow-green colored solid which represents a catalyst in which the molar ratio ΜοΟ, / FepO, has the value 3.2, the weight yield being this substance is practically quantitative.

10 ml of this catalyst were placed in a catalytic reactor and the catalyst bed was ^{heated to a starting temperature of 315 O} 0. A gas mixture containing 6.5% by volume of methanol in air was then passed over the catalyst, a volume rate based on one hour (VVH) which, based on the gaseous volume, was a value of 20 ° 0 of 7200 h. The reaction temperature, which is measured at four points on the catalyst bed, varies between 317 and 322 ° C .; the duration of this experiment was 3 hours. A material balance drawn at the end of these three hours shows that the conversion of the methanol is 99.5% and the selectivity for formaldehyde is 96%, based on the converted products; from this it is calculated that the yield of formaldehyde, based on the methanol used, is 95.4%.

-25- 0 0 9 8 3 / ₊ / 1 S Ä 3

Sheet 25 -

Example 10;

6 ml of the catalyst prepared according to Example 9 were tested under the same conditions as set out above, with the modification that this time the volume rate per hour was 36,000 h " ¹ .

The previously heated to 35O ° O catalyst bed was heated in the course of the reaction to a temperature of 350-410 ⁰ G, wherein the duration of the experiment was 5 hours.

A material balance showed that 96 % of the methanol was converted, the selectivity for formaldehyde being 96.8 % . The formaldehyde yield, based on the methanol used, was determined to be 93 % .

Example 11;

To 500 ml of a 2 M / 7 aqueous solution (353 * 2 g / l) of ammonium paramolybdate tetrahydrate, which has previously been cooled to a temperature of 5 to 12 ° C and kept under vigorous stirring, were added at a relative rate of 1200 to 2400 ml per liter and hour 171 nil of a 2 M aqueous solution (808 g / l) of iron (III) nitrate nonahydrate was added, the temperature of which was between 15 and 25 ° C.

The product obtained after hardening and maturing was then dehydrated for 48 hours at 70 ° 0 in a drying cabinet and long decomposed thereon at an "air flow at a temperature between 400 and 450 ⁰ C for 4 hours in an oven.

A green-ash-colored solid was obtained, which was the catalyst in which the molar ratio MoO, / Fe 2 O, was 5.85; the weight yield was 96 %.

6 ml of this catalyst was placed in a reactor to create a catalyst bed that was first placed on

009834/1943 -26-

- sheet 26 -

heated a temperature of 350 ° C. Then one left over the • The catalyst paint a gas mixture that consists of 6.5% by volume Methanol and otherwise consisted of air, the volume rate per hour (V.V.H.) being 24,000 h- The reaction temperature varied between 414 and 438 ° C; the duration of the experiment lasted 5 hours.

A material balance showed that 99.7 % of methanol had been converted, the selectivity for formaldehyde being 94.4 % . The formaldehyde yield, based on the methanol used, was 94.1 %.

w Example 12:

A catalyst without any further additives, its molecular ratio ΜοΟ, ΑϋΓβρΟ ^) has the value 4, was on the following Way made:

1000 ecm of a 2M / 7 (353 * 2 g / l) solution of ammonium paramolybdate tetrahydrate, which had previously been cooled to 12 ° C and kept under vigorous stirring, was mixed with 500 ml of a 2 M solution (808 g / l) of iron (III) nitrate nonahydrate, which had a temperature of less than 20 ⁰ C, was added while maintaining a relative speed of 2500 ml per liter and hour.

w The product formed by the reaction between these two solutions after hardening (one otund at 20 ° C) and ripening (30 minutes at 45 ° 0) was dehydrated for 48 hours in a drying cabinet at 65 ° C and then in a fixed bed 4 hours maintained at a temperature between 400 and 45O ⁰ C under a gentle stream of air.

In this way, with a weight yield of 95> 264 g of catalyst, which was medium green in color and had a specific surface area of 7> 4 mg ~, the molecular composition of this catalyst corresponds to the formula

009834/1 9A3 " ²⁷ "

1 MoO ₅ .

6 ml of this catalyst were placed in a catalytic reactor and the catalyst bed was initially heated to a temperature of 350.degree. A gas mixture consisting of 6.7% by volume of methanol and the rest of air was then passed over the catalyst, the volume rate per hour being VVH 24-000 h ~. The reaction temperature varied between 421 and 4-3O ⁰ O, the duration of the experiment was 6 hours.

A material balance that was drawn at the end of this experiment showed that 99 * 8 % of the methanol used had been converted, the selectivity for formaldehyde being 9512 % ; consequently the formaldehyde yield was 95%

Example 13:

The catalyst of Example 32 was tested as described above under the same conditions after it had previously been heated it to 315 ^o C. The temperature of the catalyst during the experiment was 371 to 384 ° C. The material balance indicated that 99 ₅ 8% of the methanol used had been converted, the selectivity with respect to formaldehyde was ig 97 '6%. The formaldehyde yield was therefore 97> 4 %.

Example 14-:

A catalyst mixed with silicon carbide and 20 % By weight of active phase was prepared as follows:

20 g of the catalyst prepared according to Example 9 were mixed with 80 g of powdered silicon carbide, 91 g of Senegal rubber and 20 g of water. Mixing was continued until a homogeneous paste of a very hard consistency was obtained. This paste was then its mouth a diameter of 3 mm had extruded through an extruder, and the extrudate first dried for one hour at 120 ⁰ O, then 3 hours at 250 ° C and finally 1 hour at 420 ° 0 calcined.

009834/1 9A3 ~ ²⁸ ~

Then was added 6 ml of this catalyst in a catalytic reactor, which was previously heated to 35O ⁰ C. A gas mixture, which was composed of 6.5% by volume of methanol and the rest of air, was allowed to sweep over the catalyst at a volume rate per hour of 18,000 hours. The catalyst bed was kept at a temperature between 380 and 450 ^° C. during the course of the reaction; the duration of the experiment was 6 hours.

A material balance showed that 99.5 % of methanol had been converted with a selectivity for formaldehyde of 94 % . The formaldehyde yield was therefore 93.5%

Example 15

A catalyst in which some of the iron atoms are replaced by nickel atoms was prepared in the following way:

17 ml of a 2 M aqueous solution (582 g / l) of nickel nitrate hexahydrate were added to 196 ml of an aqueous solution of 808 g / l (2'M) of iron (III) nitrate nonahydrate. The solution thus obtained, the temperature of which was kept slightly below 20 ° C., was added at a relative rate of 1600 ml per liter and hour to 5OO ml of a 2 M / 7 aqueous solution (353.2 g / l) of ammonium paramolybdate tetrahydrate, the Temperature was below 15 ° G. The resulting by the reaction of these two solutions product was dehydrated after hardening and maturing for 28 hours at 70 ⁰ G in a drying oven and decomposes then 3 hours under a gentle stream of air at a temperature between 400 and 450 ⁰ G in the fixed bed.

In this way, a catalyst was obtained with a molecular ratio of MoO, / (Fe ₂ O, +0.5 NiO) of 4.7 and an atomic ratio of Ni / (Ni + Fe) of 0.08; the color of this catalyst was pale green.

6 ml of this catalyst were eingeceben in a catalytic reactor and heated to a temperature of about 35O ⁰ G.

009834/1943 " ²⁹ ~

- sheet 29 -

A gas mixture was passed over the catalyst which was composed of 6.6% by volume of methanol and the rest of air, the hourly volume velocity VVH
24,000 hours. The reaction temperature varied between 394 and 436 ⁰ O, the duration of the experiment was 6 hours.

The material balance carried out at the end of the experiment showed that 99.6 % of the methanol used had been converted, the selectivity for formaldehyde being 93 »9 % .
The yield, based on the methanol used, was
therefore 93 * 5%

Example 16:

A catalyst in which some of the iron atoms are replaced by manganese atoms was prepared in the following way:

17 ml of a 2 M aqueous solution (574 g / l) of manganese nitrate hexahydrate were added to 196 ml of a 2 M (= 2 molar) aqueous solution (808 g / l) of iron (III) nitrate nonahydrate. the
obtained solution, which you first to a temperature of
had cooled about 20 ° G, became 500 ml at a relative rate of 2400 ml per liter per hour
2 M / 7 aqueous solution (353.2 g / l) of ammonium paramolybdate tetrahydrate, which had a temperature of less than 15 ° 0, was added. The product that resulted from the reaction between these two solutions was after the hardening and the
Maturation at about 65 ° 0 in a drying cabinet for 48 hours and then dehydrated under a gentle stream of air at a temperature between 400 and 450 ⁰ O for 3 hours im
Plague bed moved.

In this way, a catalyst was obtained with a molecular ratio _{MoO 5 AFe 2} O ₅ + Mn ₂ O ₅ ) of 4.7, the atomic ratio Mn / (Mn + Fe; 0.08; its color is gray-beige.

-30- 009834/1943

6 ml of this catalyst were placed in a catalytic reactor and heated to a temperature of about 350.degree. A gas mixture was allowed to pass over this catalyst which contained 6.5 percent by volume of methanol and otherwise consisted of air, the hourly volume rate VVH being 24,000 hours " ^1. The reaction temperature varied between 426 and 444 ⁰ O; the duration of the experiment was 5 Hours.

The material balance showed that 99 % of the methanol used had been converted, the selectivity for formaldehyde being 96.3%. The formaldehyde yield was accordingly 95.4%.

example V ?:

A catalyst in which some of the iron atoms are replaced by cobalt atoms was prepared in the following way:

196 ml of a 2 M aqueous solution (808 g / l) of iron (III) nitrate nonahydrate were mixed with 17 ml of a 2 M aqueous solution (582 g / l) of cobalt nitrate hexahydrate. The resulting solution, which was first cooled to about 20 ° C., was then added at a relative rate of 2400 ml per liter per hour to 500 ml of a 2 M / 7 aqueous solution (353 »2 g / l) of ammonium paramolybdate tetrahydrate which one had set itself to a temperature between 10 and 15 ° 0. The product obtained by the reaction of the two solutions, after hardening and ^{maturing, was dehydrated for 28 hours in a drying oven at about 70 °} C. and then decomposed under a gentle stream of air for 3 hours at a temperature between 400 and 450 ^° C. in a fixed bed.

In this way, a catalyst is obtained with a molecular ratio MoOV (Fe ₉ O, + Co ₉ O,) of 4.7 with an atomic ratio of Co / (Co + Fe) of 0.08; the color of this catalyst is beige-maroon.

-31- 009834/1943

- sheet 31 -

6 ml of this catalyst were placed in a catalytic reactor and heated to a temperature of about 315 ⁰ O. A gas mixture with a content of 6.6 vol. Methanol (remainder air). The reaction temperature varied between 320 and 384 ° C.

95-5 % of the methanol was converted, the selectivity for formaldehyde being 97-9 % , which is a particularly high value. The yield of "formaldehyde" was accordingly 93.5%

Example 18:

A catalyst in which some of the iron atoms are replaced by ear atoms was produced in the following way:

17 ml of a 2 M aqueous solution (800.4 g / l) of chromium nitrate nonahydrate became 196 ml of a 2 M aqueous solution (808 g / l) added to iron (III) nitrate nonahydrate.

The solution obtained in this way was first cooled to about 20 ° C. and then at a relative speed from 1200 to 1600 ml per liter and hour in 500 ml one 2 M / 7 aqueous solution (353> 2 g / l) of ammonium paramolybdate poured.

The resulting by the reaction of these two solutions pasty mass was dehydrated and after curing and the tire within 48 hours in a drying cabinet at about 65 C subsequently within 3 hours under a gentle stream of air at a temperature between 400 and 450 ⁰ G in a fixed bed decomposed.

In this way, a catalyst is obtained with a molecular ratio MoO ^ Z (Fe ₂ O, + Gr ₂ O,) of 4.7 and an atomic ratio of Gr / (Fe + Cr) of 0.08; this catalyst has an ocher-brown color and a specific surface area of 5 m ² / 6-

00983A / 19A3 -32-

6 ml of this catalyst were placed in a catalytic reactor and heated to a temperature of about 315 ⁰ G. A gas mixture with a content of 6.5% by volume of methanol (remainder air) was passed over this catalyst at a volume rate per hour VVH of 24,000 h * ~. The reaction temperature varied between 328 and 380 ⁰ G; the duration of the experiment was 6 hours. Here, 99 »7 % of the methanol was converted with a selectivity for formaldehyde of 97 % . The yield of formaldehyde was therefore 96.7%

Example 19 «

To 500 ml of a 2 M / 7 aqueous solution (353 g / 1) of ammonium paramolybdate tetrahydrate, which has previously been cooled to a temperature of 10 to 15 ° C and kept with vigorous stirring, was at a relative rate of about 2400 ml per A solution was added liter and hour, which was composed of 163 ^ l of a 2 M (808 g / l) solution of iron (III) nitrate nonahydrate and 19 ml of a 2 M solution (574 g / l) of manganese nitrate tetrahydrate and which had previously been brought to a temperature of about 20 ^° C.

The product that had arisen from the reaction of these two solutions was, after its hardening and maturation, ^{dehydrated within 48 hours at a temperature of 70 °} C. in a drying cabinet and then under a stream of air in an oven for 4 hours at a temperature between 400 and 450 ⁰ C decomposed.

In this way, a light beige solid was obtained, which was the catalyst; its atomic ratio Mn / (Fe + Mn) is 0.105 and its molecular ratio MoO ^ / (Fe ₂ 0, + Mn ₂ O,) is 5 * 5

6 ml of this catalyst were placed in a catalytic reactor, wherein the catalyst bed is previously heated to a temperature

-33-0 0 9 8 3 A / 1 9 U 3

of 35O ° C had heated. A gas mixture which contained 6.6 percent by volume of methanol and the remainder of air was then passed over this catalyst at an hourly volume rate VVH of 24,000 hours. The reaction temperature varied between 412 and 444 ⁰ O; the duration of the experiment was 5 hours.

A material balance showed that 99.3 % of the methanol had been converted, the selectivity for formaldehyde, based on the converted product, being 97 % ; the yield of formaldehyde was therefore 96.3%

Example 20:

A catalyst which corresponds to the stoichiometric iron (III) molybdate of the formula Fe ₂ (MoO ^) X, but in which some of the iron ions are replaced by cobalt ions, was produced in the following manner:

To 500 ml of a 2 M / 7 aqueous solution (353 * 2 g / l) of ammonium paramolybdate tetrahydrate, which was previously cooled to a temperature of 10 to 15 ° C and kept under vigorous stirring, were added at a relative rate of about 1600 ml per liter and hour, a solution consisting of 287 ml a 2M solution (808 g / l) of iron (III) nitrate nonahydrate, and from 47 ml of a 2M solution (582 g / l) of cobalt nitrate hexahydrate composed which total solution had previously been cooled to a temperature of less than 20 0.

The mass obtained by reacting these two solutions was initially dehydrated after hardening and maturing at about 65 ° C. in a drying cabinet within 48 hours and then under a gentle stream of air at a temperature between 400 and 450 ⁰ O for 3 hours Fixed bed decomposes.

-34- 009834/1943

- sheet 34 -

In this way, a catalyst is obtained which has an ocher-brown color and the formula Fe ₀ Co (MoO.,.) - ,, with χ = 0.28.

6 ml of this catalyst was placed in a catalytic reactor and heated to a temperature of about 350 ° C. One left Then brush a gas mixture over this catalyst, which was composed of 6.6% by volume of methanol, the remainder being air; the The catalyst bed had a temperature of 407 to 442 ° C; the "experiment lasted 5 hours.

The material balance showed that 99.8 % of the methanol used; w had been converted; the selectivity with respect to. Formaldehyde was 96 %. The yield of formaldehyde was therefore 95.8-

Example 21:

A catalyst in which the iron is (partially) replaced by chromium and cobalt at the same time was prepared according to the general procedure described above. The catalyst had the following molecular composition: MoO ₃ «80.31 % .; Fe ₂ O ₃ = 16.21 % ; Cr ₃ O ₃ - 0.73 % ; CoO = 2.75%.

6 ml of this catalyst were placed in a catalytic reactor, the catalytic bed had been previously heated to a temperature of 315 ⁰ C. A gas mixture composed of 6.7% by volume of methanol, the remainder being air, was passed over this catalyst, with a volume rate per hour, expressed in parts by volume of the gaseous reactant (TPN) per part by volume of catalyst and per hour of 24,000 h ~ was adhered to. The reaction temperature varied between 322 and 389 ^° C., the duration of the experiment was 6 hours. A material balance, which was drawn at the end of the experiment, showed that 99.3% of the methanol used had been converted, the selectivity with respect to formaldehyde being 97-3%; the

0098 3-4 / 19 * 3 " ³⁵ ~

The formaldehyde yield was accordingly 96.6 %.

Example 22:

A catalyst was produced in which the iron was partially replaced by ghrome and manganese; this catalyst has the following molecular composition, which is given as a percentage:
MoO ₅ = 81.47 % ; Fe ₂ O ₅ = 16.40%; Or ₃ O ₅ = 0.74% Mn ₂ O ₅ > 1.39%

This catalyst was tested under the same conditions as described in Example 21.

The material balance, which was carried out at the end of the experiment, showed that 97.7 % of methanol had been converted, the selectivity for formaldehyde being 97-9%. The formaldehyde yield was accordingly 95.6 %.

Example 23-

A catalyst that contains manganese and cobalt. That partially Replacing the iron was made according to the general procedure outlined above. This catalyst has the following molar composition, which is given as a percentage:

MoO ₅ - 80.46 % \ Fe ₂ O ₅ >> 17.05 % \ Mn ₂ O ₅ = 1.34%; GoO = 1.15% ♦

With this catalyst it is possible to convert more than 99.8% methanol, the selectivity with respect to formaldehyde being 97.5%. The yield of formaldehyde was therefore 97.3 % -

Example 24:

A catalyst is produced in which some of the molybdenum ions are replaced by vanadium ions:

Dissolve 1.86 g of vanadyl oxalate VO (G 0 ^) ₂ in 114 ml of a 2 M

-36- 009834 / 19A3

- sheet 36 -

Solution of ammonium paramolybdate tetrahydrate (353.2 g / l), whereby a liquid of dark blue color is formed. This liquid is treated with 8 ml of a solution of hydrogen peroxide to 110 parts by volume in order to make the solution oxidizing and to prevent this iron (III) salts from being reduced to iron (H) salts; here the solution takes on an intense red color; it is then cooled to 10 ⁰ C and treated with 60 ml of a 2M solution of iron (IH) nitrate (808 g / l), which have been previously cooled to a temperature of 15 ° C, while maintaining a relative speed of 5000 ml per liter and hour added. The resulting brick-red suspension, the color of which is a result of the formation of permolybdate ions MoO ^ -), is slowly heated within 30 minutes until the bulk of the solution has formed a reddish-colored gel. This is then within 3 days dried in a drying oven at 65 ° C. Within an hour, the product takes on its own green color again as a result of the decomposition of the permolybdate ions, with a progressive transformation as a result of the heating into a brown-red, hard and brittle gel If this product decomposes in the air within a period of 1 to 3 hours, a catalyst with the molar ratio is obtained

- ^ - 2— = 0.25 and the atomic ratio = 0.05

Mo0 _$ + 1/2 V ₂ O ₅ Mo + V

The catalyst yield is 96% by weight.

The catalyst produced in this way was tested in compliance with the standard process conditions already described above; the reaction temperature varied between 344 and 4-39 ⁰ C; the duration of the experiment was 6 hours.

The material balance, which was drawn at the end of the experiment, showed that 99 »6 % ! Ethanol had been converted, the selectivity with regard to formaldehyde being 92.9 % ; the

009834/1943 ~ ³⁷ ~

- Sheet 37 yield of formaldehyde is 92.5%

example 2 *? '·

At a relative speed of 2200 Priority ml per liter per hour 98 ml of a 2 M aqueous solution (808 g / l) of iron (III) nitrate nonahydrate, which had been previously adjusted to 20 ⁰ G, added to an aqueous solution , which in turn consists of 250 ml of a 2M / 7 aqueous solution of ammonium paramolybdate tetrahydrate (353.2 g / l) and 17 ml of a M / 2 aqueous solution of ammonium dichromate (126.05 g / l) ° C had been cooled. The reaction between the two solutions results in the formation of a yellow colored opalescent gel that is hard and brittle; this gel is transformed by drying for three days at 65 ° C into a new product, brown-red color, which is transparent, hard and brittle. Therefrom to obtain a catalyst with the molecular ratio by thermal decomposition under a gentle air flow within 3 hours at 4-20 ⁰ C.

₀ O, ρ

² 3 ^Or _a η 033

° ' ¹⁹ ' ^whose atomic ratio _{Mo + Gr}

■ ° ' ¹⁹ ' ^whose atomic ratio _{Mo + Gr} 3 3

reads.

The catalyst prepared in this way was tested under the standard reaction conditions shown in Example 23; the reaction temperature varied between 398 and 44-3 ° C; the experiment lasted 6 hours; the material balance showed that 9912% of the methanol had been converted, the selectivity for formaldehyde being 94.1 % ; the yield of formaldehyde is therefore 933%

Example 26;

At a relative speed of 3000 Priority ml per liter per hour 125 ml of a 2M aqueous solution (808 g / l)

009834/1943 -38-

ßAD ORlGfNAL

- sheet 38 '-

of iron (III) nitrate nonaliydrate, which has previously been ^{cooled to about 20 0} G, to an aqueous solution, which in turn is made up of 24-5 ml of a 2M / 7 aqueous solution of ammonium paramolybdate tetrahydrate (353.2 g / l) and from 5 ml of a 2M / 12 aqueous solution of ammonium metatungstate to 92.05 ° / o WO, and comprised a content of 503.8 g of salt per liter, which was 250 ml of the aqueous mixed solution to 10 to even 15 ° C set . The resulting suspension is slightly heated, becoming massive within 15 minutes. This mass changes within τοη one hour at 60 ° C spontaneously as a result of ripening into a green, transparent gel. This gel product is then dried for 3 days at 60 to 65 ° C., a new brown-red colored, transparent, hard and brittle product being formed. Thermal decomposition of this product under a gentle stream of air for 3 to 5 hours at 400 to 450 G gives a catalyst with the molecular ratio

Fe _p 0, V

- = - 2 = 0.25, and the atomic ratio = 0.02,

MoO ₂ + WO ₇ . Mon + W

3 3

the weight yield being practically quantitative.

6 ml of this catalyst are tested according to the conditions described in Example 23; the reaction temperature varies between 353 and 4-38 ⁰ G, the experiment lasts 6 hours. 99.5 % of methanol was converted, the selectivity to formaldehyde being 96.1%. The formaldehyde yield was accordingly 95.7 %

Example 27: ■

A catalyst in which molybdenum or iron is replaced by tungsten or .. Ghrom (partially) replaced, was manufactured in the following way:

A solution A was prepared from 110 ml of a 2M aqueous

-39-009834 / 1943

BATH ORIGINAL

- sheet 39 -

Solution of iron (III) nitrate nonahydrate (808 g / l) and 9.5 ml a 2M aqueous solution of chromium nitrate nonahydrate (800.4 g / l) consists. This solution A is cooled to 15 ° C. beforehand.

In addition, a solution B is prepared, which is made up of 250 ml of a 2M / 7 aqueous solution of ammonium paramolybdate tetrahydrate (353 ^ 2 g / l) and 13 ml of a 2M / 12 solution of ammonium metatungstate with a content of 92.05 % WO, composed. This solution B is cooled to 10 ° C. beforehand.

Then the solution B is placed in a vessel, cooled to 0 ° 0 and then the solution A is added at a relative speed of 2000 ml per liter and hour. The resulting mixture is then gently heated; here will It is massive at a temperature of 15 ° G and turns into a gel of dark green color after ripening. This gel will then dried for 2 days at 70 ° 0; it creates a new gel of dark brown color that is transparent. The latter gel is finally thermally decomposed at 400 G within 3 hours, whereby a catalyst of the following molecular Composition obtained, where this information is expressed as a percentage:

⁰ M WO ₃ = 4.07 % \

6 ml of this catalyst are placed in a catalytic reactor and tested according to the process conditions of Example 23; this experiment lasts 8 hours, the reaction temperature varying between 300 and 376 ° C .; the material balance shows that 99.5 % of methanol was converted, the selectivity with respect to formaldehyde being 96.4%; the formaldehyde yield is accordingly 96 %.

-40- / claims; 009834/1943

Claims (22)

- Sheet 40 - claims 1.) Process for the production of a new transparent gel with a content of molybdenum and iron, characterized in that a solution of a molybdenum compound is allowed to react with the solution of an iron (III ^ compound while stirring that the concentrations of these solutions between 0 , 1 and 2.5 gram-atom per liter with respect to the molybdenum and between 0.3 gram-atom per liter and the degree of saturation with respect to the iron, that furthermore the reaction temperature is between the congelling temperature of the solutions and 30 ⁰ C, and the amounts the solutions used are chosen so that the atomic ratio Mo / JFe is between 0.4 and 5. 2.) The method according to claim 1, characterized in that in addition to the solution of the molybdenum compound and the Solution of the iron (III) compound a solution of at least one metal M also take part in the implementation leaves, where M stands for cobalt, nickel, manganese, bromine, scandium, yttrium and the rare earths (ordinal numbers 57 "to 71 including), and the amounts of the solutions used are chosen such that the atomic ratio M / (M + Fe) is below 0.5 and the atomic ratio Mo / (M + Fe) is between 0.4 and 5. 3.) The method according to claim 1, characterized in that one a \ isser the solution of the molybdenum compound and the g of the iron (III) compound also has a solution st a prebonding of at least one metal IC 'it would take part in the reaction, where K for chromium, l? ■ · -.:. ] '■ · ■ .-, τ--. Van.'iduniu uranium or chromium M = PhI; and uv . ■■ '"■ r Vn-. Li'r-jiC-./i ί Mir M sii.pi: v ^ ra ^ B - sheet 41 - and that such quantities of solutions are used that that Atomic ratio below 05 and the atomic ratio below 0.5 and the atomic ratio is between 0.4 and 5. 4.) Method according to claim 1, characterized in that apart from the solution containing molybdenum and apart from the solution containing iron, a solution of at least one compound at least one metal M in cationic form, where M for cobalt, nickel, manganese, chromium, scandium, Yttrium and the rare earths' (atomic numbers 57 to 71 including) and 'furthermore a solution of at least one compound of at least one metal K, which is for Chromium, tungsten, manganese, vanadium and uranium stands, whereby chromium, tungsten and manganese are in anionic form, can participate and that the amounts of the solutions used are chosen in such a way that the atomic ratios M Ή ■ and ■ each below 0.5 and the atomic ratio Mon + N
ratio ■ lie or lies between 0.4 and 5. 5.) Process according to Claims 1 to 4, characterized in that after the complete addition of the solutions obtained mixture heated to boiling temperature and after evaporation of at least part of the solvent heated in a drying apparatus to a temperature between 40 and 120 ° C. 6.) The method according to claim 1, characterized in that the molybdenum is in the form of an aqueous ammonium molybdate solution a concentration of 1 to 2.5 gram-atom per liter that you get the trivalent iron in the form of a aqueous iron nitrate solution with a concentration between 1 gram ion per liter and the saturation concentration begins and that the reaction temperature to a value -42- 00983 47 1943 ORIGINAL INSPECTED - Sheet 42 - between, the congealing temperature of the solutions and 20 ° G is set and the corresponding amounts of Solutions are selected so that the atomic ratio Mo / Fe is between 1.5 and 5. 7.) Process according to Claims 2 to 4, characterized in that that the molybdenum in the form of an aqueous solution of ammonium molybdate with a concentration of 1 to 2.5 gram-atom per liter, the trivalent iron in the form of an aqueous nitrate solution with a concentration between 1 gram of iron ion per liter and the degree of saturation that the reaction temperature sets in a value between the congelling temperature of the solutions and 20 ° C and that the corresponding amounts of the solutions chooses such that the atomic ratio 1.5 to 5. 8.) Process according to claims 6 or 7> characterized in that d,
lies. net that the B " ⁴ action temperature between 0 and 15 ° C 9) Process according to Claims 6 to 8, characterized in that that the solution containing the iron to the solution containing the molybdenum at a relative speed add from 200 to 3000 ml per liter and hour. 10.) Process according to Claims 1 to 9, characterized in that the solution containing the molybdenum compound contains ammonia beforehand. 11.) Process according to claims 1 to 10, characterized in that the solution containing the compound of trivalent iron, in advance an acid from the group nitric acid, sulfuric acid, hydrochloric acid , phosphoric acid, formic acid, perchloric acid and ETuor- 009834/194 3 adding hydrochloric acid. 12.) Process according to claims 1 to 11, characterized in that the product obtained from this mixing of the Molybdenum compound, the iron (III) compound and "optionally the compound of the metals M and N were formed is, a mineral salt of the group ammonium chloride, ammonium perchlorate and ammonium nitrate is added. 13.) Process according to Claims 1 to 12, characterized in that that you then the gel mass formed at a temperature between 40 and 150 ° C within a Dehydrated time sufficient to achieve a residual water content of less than 10% by weight. 14.) gels, characterized in that they according to the procedure of claims 1 to 12 are obtained. 15.) Dehydrated gels, characterized in that they according to the procedure of claim 13 are obtained. 16.) Use of the gels according to claims 14 and 15 as optical filters. I ?.) Use of the gels according to claims 14 · and 15 as Precursors for mixed oxides containing molybdenum and iron, these mixed oxides being obtained by thermal decomposition of these gels. 18.) Misschoxyde, characterized in that they are through thermal decomposition of the gels according to claims 14 and 15. 19.) Use of the according to one of claims 6 to 9 received on ⁽ ϊ <le for the production of catalysts for the «:.: ■% (]? '! Γϋ-' .-. NoΠUJu- vm catching up in AJueh ^ de by BAD OFUG1N ^AL - Sheet MA- - thermal decomposition of these gels, which is carried out at a temperature between 300 and 500 ^° C. and within a period of less than 6 hours. 20.) Use according to claim 19, characterized in that the gels are previously dehydrated according to claim 13. 21.) Use according to one of claims 19 or 20, characterized in that the gel by extrusion, Spinning, tablet formation, kneading or casting and dividing before drying and thermal decomposition machined to shape. 22.) Catalysts, characterized in that they are obtained according to one of claims 19 "to 21. 23) Catalysts according to claim 22, characterized in that that they are mixed with a catalytically inert phase. 2A-.) Use of the catalysts according to one of the claims 22 or 23 in the pure state or in a diluted state with a catalytically inert phase for the oxidation of alcohols to aldehydes. '25.) Use of the catalysts according to one of the claims 22 or 23 in the pure state or in a diluted state with a catalytically inert phase for the oxidation of methanol to formaldehyde. 9 J / ■ ·: I 1 9 - '. 3 ÖA ORIGINA Blank page