CH703845B1 - Production of aluminum phosphates with recovery of templates. - Google Patents

Abstract

The present invention relates to the preparation of alumino-phosphates with recovery of templates, comprising the steps of a) providing a reaction mixture of an aluminum source, a phosphate source and a template in water, b) reacting the starting materials under hydrothermal conditions in one Reactor to an alumino-phosphate, c) releasing the pressure in the reactor and collecting a template-escaping mixture from the reactor, which cools down under expansion and condenses, d) separating the template from the mixture, e) returning the template in step a), which results in a more cost-effective and environmentally friendly process, as re-obtaining templates alumo-phosphates can be obtained.

Description

The present invention relates to the production of aluminophosphates with the recovery of templates.

The structural classification of porous aluminophosphates is carried out according to the "Structure Commission of the International Zeolite Association" on the basis of their pore sizes in accordance with the IUPAC rules (International Union of Pure and Applied Chemistry). The crystalline substances are obtained in more than two hundred different compounds in two dozen different structures (topologies). Classified into small, medium and large pore compounds, they have pore sizes from 0.3 nm to 0.8 nm. During the synthesis, the characteristic pore size is influenced not only by the synthesis parameters such as pH, pressure and temperature but also by the organic structure-directing templates used.

Find use of aluminophosphates as absorbents, as active and selective catalyst components for processes in the refining of petroleum, in stationary and mobile exhaust gas cleaning, as well as in conversion reactions of oxygenates or aromatics, and much more.

The framework structures of the aluminophosphates are built up from regular, three-dimensional spatial networks with characteristic pores and channels that can be linked to one another in one, two or three dimensions. The calcined structures are made up of corner-linked tetrahedral units (AlO4, PO4, possibly SiO4), each consisting of aluminum and phosphorus coordinated four times by oxygen, and possibly silicon (SAPO). The tetrahedron units are referred to as primary structural units, the connection of which leads to the formation of secondary structural units (pores, channels, etc.).

In aluminophosphates, due to the balanced number of aluminum and phosphorus atoms, charge neutrality prevails. The isomorphic exchange of phosphorus with silicon creates excess negative charges in silico-aluminophosphates (SAPO), which are balanced out by the storage of additional cations in the pore and channel system. The degree of phosphorus-silicon exchange thus determines the number of cations required for compensation and thus the maximum loading of the compound with positively charged cations, e.g. Hydrogen or metal ions. By incorporating the cations, the catalytic properties of the aluminophosphates are determined and their activity and selectivity as catalyst components can be improved through targeted ion exchange.

Metal-exchanged aluminophosphates find various uses due to their diverse catalytic properties. Metal-exchanged aluminophosphates with silicon (SAPO), iron (FeAPO), titanium (TiAPO), chromium (CrAPO), manganese (MnAPO), gallium (GaAPO), zinc (ZnAPO), cobalt (CoAPO), nickel are known (NiAPO) and much more

[0007] Alumino-phosphates can be produced by various methods. Usually these are produced by hydrothermal crystallization, starting from reactive aluminum, phosphate or silicon sources (in the case of silico-aluminophosphates).

In the prior art, various processes for the production of aluminophosphates are known in which structure-directing templates are used. The desired structures can be obtained by adding templates.

DE 3 873 726 T2 describes a method for producing non-zeolitic molecular sieves, starting from preformed bodies made of alumina or silica-alumina with the addition of various oxides and organic templates. No. 4,440,871 describes a hydrothermal process for obtaining substituted alumino-phosphates, silico-alumino-phosphates, starting from silicon, aluminum and phosphorus in the presence of organic, structure-directing templates. According to EP 0 132 708, metal-exchanged aluminophosphates can be obtained in the presence of metals, aluminum and phosphorus sources by means of templates. EP 0 159 624 B2 also describes the preparation of metal-exchanged silico-alumino-phosphates by means of hydrothermal synthesis, starting from corresponding silicon, aluminum and phosphate sources and structure-directing templates.

[0010] Nitrogen-containing organic and inorganic substances are used as structure-directing templates, including quaternary ammonium cations, amines (primary, secondary, tertiary or cyclic), azines, imines or alkanolamines, etc. In addition, various metal complexes or ionic liquids can be used, which are both template and solvent at the same time.

Template molecules are embedded in the pores of the aluminophosphates and thus influence the size of the secondary structural units during synthesis. The use of the same template can lead to the formation of different aluminophosphate structures or the same structure can be obtained by using different templates.

In these methods, which are known from the prior art, however, it is disadvantageous that very large amounts of structure-directing templates have to be used. A large part of the template used remains in the mother liquor when the products are separated off, which is then discarded. Furthermore, the pore and framework system of the crystalline aluminophosphates still contains a lot of template, which first has to be removed in a further work step, which is costly by calcination at high temperatures (350 ° C-500 ° C) or absorption (EP 1 873 470 A2) .

There was therefore a need to provide a method for producing crystalline aluminophosphates by means of template synthesis, in which the consumption of organic structure-directing templates is low and can be recovered efficiently and inexpensively from the synthesis mixture with the template without additional effort .

[0014] The object of the present invention was therefore to provide a process for the preparation of aluminophosphates which enables the synthesis of crystalline aluminophosphates with little consumption of templates.

According to the invention this object is achieved by a process for the production of alumino-phosphates, comprising the steps of a) providing a reaction mixture of an aluminum source, a phosphate source and a template in water, b) reacting the starting materials under hydrothermal conditions Conditions in a reactor to form an alumino-phosphate, c) releasing the pressure in the reactor and collecting a template-containing mixture escaping from the reactor, which cools and condenses with expansion, d) separating the template from the mixture, e) recirculating the Templats in step a).

Surprisingly, up to 50% of the template used can be recovered from the reaction mixture by letting down the pressure, and used again for the production of aluminophosphates.

The template contained in the mixture is separated from the condensate with separation, obtained and can be returned to step a) of the process according to the invention.

Under alumino-phosphates (general formula (AlPO4-n)) are understood in the context of the present invention microporous alumino-phosphates.

These are alumino-phosphates (AlPO) of the following type: AlPO-5, AlPO-8, AlPO-11, AlPO-16, AlPO-17, AlPO-18, AlPO-20, AlPO-31, AlPO- 34, AlPO-35, AlPO-36, AlPO-37, AlPO-40, AlPO-41, AlPO-42, AlPO-44, AlPO-47, AlPO-56. AlPO-5 is particularly preferred.

The term aluminum phosphate is used in the context of the present invention, according to the definition of the International Mineralogical Association (DS Coombs et al., Can. Mineralogist, 35, 1997, 1571), a crystalline substance from the group of aluminum Understood phosphates with a spatial network structure. The aluminum phosphates present are classified according to the IUPAC (International Union of Pure and Applied Chemistry) and the Structure Commission of the International Zeolite Association based on their pore size. The three-dimensional network structure has characteristic pores and channels that can be connected to one another in one, two or three dimensions via tetrahedra (AlO4, SiO4, PO4) linked to each other. The Al / P / Si tetrahedra are called primary building units, the connection of which leads to the formation of the typical framework structure.

Starting from alumino-phosphates, so-called silico-alumino-phosphates, which correspond to the general formula (SixAlyPz) O2 (anhydrous), are obtained by isomorphic exchange of phosphorus, for example with silicon.

Particularly suitable are aluminophosphates that have a partial replacement of phosphorus by silicon, with a Si / (Al + P) ratio of 0.01: 1 to 0.5: 1, preferably 0.02: 1 to 0.2: 1.

In one embodiment of the invention, microporous silico-alumino-phosphates (SAPO) of the following type can be used, SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO- 20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-48, SAPO-56. SAPO-5, SAPO-11, SAPO-34 are particularly preferred.

A part of the phosphorus of the inventive aluminophosphates can also be replaced by titanium, iron, manganese, copper, cobalt, chromium, zinc and / or nickel. These are usually referred to as, FeAPOs, TiAPOs, MnAPOs, CuAPOs, CoAPOs, CrAPOs, ZnAPOs, CoAPOs or NiAPOs. The types MAPO-5, MAPO-8, MAPO-11, MAPO-16, MAPO-17, MAPO-18, MAPO-20, MAPO-31, MAPO-34, MAPO-35, MAPO-36, MAPO are particularly suitable -37, MAPO-40, MAPO-41, MAPO-42, MAPO-44, MAPO-47, MAPO-48, MAPO-56 (with M = Ti, Fe, Mn, Cu, Co, Cr, Zn, Ni) .

In addition to silicon, the aluminophosphates according to the invention can also contain other metals. Ion exchange with titanium, iron, manganese, copper, cobalt, chromium, zinc and nickel has proven to be particularly advantageous. TiSAPO, FeSAPO, MnSAPO, CuSAPO, CoSAPO, CrSAPO, ZnSAPO, NiSAPO are particularly suitable.

According to the invention, the SAPOs can also be doped in which metal is built into the framework. Dopings with titanium, iron, manganese, copper, cobalt, chromium, zinc and nickel have proven to be particularly advantageous. FeAPSO, TiAPSO, MnAPSO, CuAPSO, CrAPSO, ZnAPSO, CoAPSO and NiAPSO are particularly suitable.

These can be present as microporous MAPSOs (M = Ti, Mn, Cu, Cr, Zn, Co, Ni), such as MAPSO-5, MAPSO-8, MAPSO-11, MAPSO-16, MAPSO-17, MAPSO- 18, MAPSO-20, MAPSO-31, MAPSO-34, MAPSO-35, MAPSO-36, MAPSO-37, MAPSO-40, MAPSO-41, MAPSO-42, MAPSO-44, MAPSO-47, MAPSO-56. MAPSO-5, MAPSO-11 or MAPSO-34 are particularly preferably used.

In an inventive alumino-phosphate can further contain at least one further metal, selected from the group containing silicon, titanium, iron, manganese, copper, cobalt, chromium, zinc and nickel. The incorporation of one or more other metals improves the adsorption properties of the aluminophosphates. These are usually referred to as SiMAPOs, FeMAPOs, TiMAPOs, MnMAPOs, CuMAPOs, CoMAPOs, CrMAPOs, ZnMAPOs or NiMAPOs.

Furthermore, zeolites can also be obtained by the process according to the invention. Zeolites in particular have cavities, in addition to channels that are characteristic of every zeolite. The zeolites are divided into different structures according to their topology. The zeolite framework contains open cavities in the form of channels and cages, which are normally filled with water molecules and additional framework cations that can be exchanged. There is an excess negative charge on an aluminum atom, which is compensated by cations. The interior of the pore system represents the catalytically active surface. The more aluminum and the less silicon a zeolite contains, the denser the negative charge in its lattice and the more polar its inner surface. The pore size and structure is determined by the parameters during production (ie the use and type of templates, pH, pressure, temperature, presence of seed crystals) by the Si / Al ratio, which determines most of the catalytic character of a zeolite .

The presence of bivalent or trivalent cations as the tetrahedral center in the zeolite structure gives the zeolite a negative charge in the form of so-called anion sites, in the vicinity of which the corresponding cation positions are located. The negative charge is compensated by the incorporation of cations into the pores of the zeolite material.

In a pure, non-ion-exchanged zeolite, these are usually H + ions, which induce Brönsted acid properties, but which can also be exchanged for other M <n +> ions in the lattice. In the classic Al-containing zeolites, these trivalent cations, which induce Brönsted acidity, are Al <3+> ions. Accordingly, pure silicates and titanium silicates contain no Brönsted acidity and no possibility of exchanging H <+> ions for other ions.

The zeolites are mainly differentiated according to the geometry of the cavities which are formed by the rigid network of the SiO4 / AlO4 tetrahedra. The entrances to the cavities are formed by 8, 10 or 12 rings, which are narrow, medium or wide-pored zeolites. Certain zeolites show a uniform structure, e.g. the ZSM-5 or the MFI topology, with linear or zigzag channels. In others, larger cavities connect behind the pore openings, e.g. for the Y or A zeolites with the topologies FAD and LTA.

According to a preferred embodiment of the zeolite according to the invention, it is selected from a group consisting of AEL, BEA, CHA, EUO, FAU, FER, KFI, LTA, LTL, MAZ, MOR, MEL, MTW, LEV, OFF, TON and CHA.

In principle, any zeolite can be used in the context of the present invention, in particular any 10- and 12-ring zeolite. According to the invention, however, zeolites are preferred which are selected from the group of topologies AEL, BEA, CHA, EUO, FAU, FER, KFI, LTA, LTL, MAZ, MFI, MOR, MEL, MTW, LEV, OFF, TON and CHA, the topologies BEA, MFI, FER, MOR, MTW and CHA are very particularly preferred.

According to the invention, “template” is understood to mean predominantly organic and inorganic nitrogen-containing compounds which are added to the reaction mixture as structure-directing agents (SDA) in order to obtain crystalline aluminophosphates. Structure-directing templates influence the formation of the crystal lattice during synthesis. They support crystal growth because the tetrahedral units (ALO4, PO4, SiO4) attach to the template molecules and thus form the precursor for the characteristic framework structure. Furthermore, the chemical potential is changed by adding a template, which means that the energy that has to be expended for lattice formation is reduced by the incorporation of the template during the synthesis. This energetic stabilization is achieved through interactions between the template and the tetrahedral units (such as hydrogen bonds, van der Waals forces, electrostatic and London interactions). The size, shape and chemical properties of the template thus have an effect on the resulting structure, since the template creates and stabilizes a special framework structure with pores and channels.

The influence of the template in the crystal formation of aluminophosphates further depends on its solubility and stability under the corresponding hydrothermal synthesis conditions. The structure-directing effect can be induced by added organic as well as inorganic molecules, which can be charge-neutral or ionic.

It is important to distinguish between “real” structure-directing templates such as the tetrapropylammonium cation, and those templates that only serve as “pore fillers”. Depending on the silicon content, with SAPOs, for example, the resulting crystal lattice can be stabilized via hydrophobic interactions with pore fillers such as long-chain, bifunctional amines, voluminous amines or alcohols.

Ammonium salts, quaternary ammonium salts, (primary, secondary, tertiary or cyclic) amines, alkanolamines, azines, diamines, heterocyclic nitrogen-containing substances, alkyl-substituted amines, alkanolamines, imines are used as templates.

The templates are selected from a group consisting of: tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, n-butylammonium, hydroxide, fluoride, chloride, bromide, iodide, nitrate, di -n-propylamine, tripropylamine, triethylamine, triethanolamine, diethanolamine, polyamines, 1,6-hexanediamine, 1,3-propanediamine, triethylenetetramine, hydroxide, fluoride, chloride, bromide, iodide, nitrate, piperidine, cyclohexylamine , 2-methylpyridine, N, N-dimethylbenzylamine, N, N-diethylethanolamine, dicyclohexylamine, N, N-dimethylethanolamine, choline, N, N'-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, N- Methyldiethanolamine, N-methylethanolamine, N-methylpiperidine, quinuclidine, N, N'-dimethyl-1,4-diazabicyclo [2,2,2] octanion, di-n-butylamine, neopentylamine, di-n-pentylamine, isopropylamine, t -Butylamine, n-butylamine, ethylenediamine, pyrrolidine, 2-imidazolidone, hexamethylimine, 4,4-dimethyl-4-azonia-tricyclo [5.2.2.02.6] undec-8-ene hydroxide (OSDA).

According to a preferred embodiment of the method according to the invention, however, triethylamine (TEA) is used as the template.

In addition, templates are also understood to mean other organic compounds such as polymers, alcohols (monohydric and polyhydric alcohols), ketones, polyethylene glycol or sulfur-containing compounds.

Under hydrothermal conditions is understood below that in a reactor at a pressure of 1 bar to 50 bar, preferably at 1 bar to 25 bar at a temperature of 50 to 300 ° C, preferably at 70 ° C to 250 ° C over a period of a few hours 1 h to 24 h up to several days 1 d to 10 d, the conversion of an aluminum source, a phosphate source and possibly a silicon source and possibly metals M (with M = Ti, Fe, Mn, Cu, Co, Cr, Zn, Ni) takes place together with organic structure-directing templates in an aqueous solution. By adding the templates, the desired pore and framework structure is "built around" the corresponding template molecules under the applied hydrothermal conditions, i.e. they act as crystallization nuclei. The framework structure can be further influenced by varying the hydrothermal conditions such as pressure and temperature.

The grain size of the crystalline aluminophosphates can be reduced by the additional action of microwave radiation, whereby nanoparticulate aluminophosphates are obtained.

A reactor according to the invention is, for example, a pressure-tight, heatable, cylindrical pressure vessel made of steel. The reactor can also be equipped with a stirrer shaft and stirrer elements. Optionally, the reactor has a lifting-and-lowering device.

The capacity of such a reactor is 1 liter to 200 liters, but can also be 1000 to 100,000 liters.

This can be operated at temperatures between 70 ° C to 250 ° C, for example via electrical heating, in an oil bath or in steam and at a pressure range from 1 bar to 100 bar. The reactor can, for example, be equipped with a high-pressure safety system with a quick release fastener, pressure-tight valves and a classic double jacket.

According to the invention, aluminum oxide, pseudoboehmite, sodium aluminate, aluminosilicates, etc. can be used as the aluminum source.

Furthermore, any phosphorus oxide, hydrogen / dihydrogen phosphate, phosphoric acid, etc. can be used in appropriate purity as the phosphate source in the process according to the invention. As well as metal phosphates MPO4 with M = Li, Na, K, Ca, Mg, Sr, B, Al, Ga, In, Tl, Si, Ge, Sn, Zn, Pb, Ti, Fe, Mn, Cu, Ag, Au , Pd, Pt, Co, Cr, Zn, Ni, Rh, Ru, Te, Tl.

The metal compounds used for the synthesis can be used as oxides, salts with inorganic or organic radicals, depending on the reaction mixture, so that good solubility is ensured.

In the method according to the invention, any silicon source, such as SiO2 powder, silica sols, aluminosilicates, etc. can be used.

A Malvern Mastersizer (obtained from Malvern Instruments GmbH, Germany) was used to determine the average particle size of the SiO2 powder. For the measurement, the SiO2 powder was presented in analytically pure n-hexane.

According to the invention, the SiO2 can also be used in a purity of 99.99%. It is of particular advantage that the use of silico-aluminophosphates gives rise to particularly high temperature stability at high temperatures.

According to a preferred embodiment of the method according to the invention, the SiO2 powder has a BET surface area of 35 m 2 / g to 70 m 2 / g. The SiO2 powder more preferably has a BET surface area of 40 m 2 / g to 65 m 2 / g, more preferably 45 m 2 / g to 55 m 2 / g. The high BET surface area of the SiO2 powder leads to an increased reactivity during the conversion to silico-aluminophosphates.

The BET surface area of the SiO2 powder is determined by means of adsorption of nitrogen in accordance with DIN 66 131 and DIN 66 132. A publication of the BET method can be found in J. Am. Chem. Soc. 60, 309 (1938).

According to a further advantageous development of the method according to the invention, the aluminum hydroxide powder has an average particle size of 10 μm to 200 μm, more preferably 20 μm to 150 μm and in particular 20 μm to 100 μm.

The recovery of the template from the reaction mixture takes place according to the invention by opening the hot, pressurized reactor. The hot, pressurized reaction mixture, containing template, gas, water, possibly solvent, possibly impurities, is transferred via a connection into a further reactor or a closed vessel in which the reaction mixture is collected, whereupon it cools and expands condensed out. In this way a solution of the reaction mixture is obtained in the further reactor which can be separated into its constituents. It is particularly advantageous that, due to the expansion of the reaction mixture under pressure, no further energy supply is necessary in order to obtain a solution and thus simply separate the template from the reaction mixture in the first reactor.

According to the invention, the solution obtained by condensation in the further reactor, containing template, water, optionally solvent, etc., is separated into the individual components so that the template can be used again in a further synthesis. It is particularly advantageous that, by opening the hot, pressurized reactor, the reaction mixture contained in the reaction mixture can be removed therefrom by cooling it down as a result of expansion (Joule-Thomson effect) and accumulating as a solution in another reactor . The composition of the “escaping” reaction mixture can be controlled. At the beginning, a pressurized reaction mixture is obtained, which consists mainly of template and organic more volatile constituents, the longer an open connection between the first reactor and the second reactor is maintained, the more water-containing the captured reaction mixture. It is therefore of particular advantage if the first reactor is only opened “briefly” depending on the amount of reaction mixture, since a template-containing solution is thus obtained in the further reactor. In particular, a longer open connection also increasingly carries impurities from the first reactor into the further reactor, which makes the separation in order to obtain pure template more difficult. The separation can possibly be omitted or is at least much simpler if less water is contained, whereby costs and resources can be saved.

It is advantageous that by removing the hot, pressurized reaction mixture, predominantly water and template are removed and the template is therefore obtained in pure form after the water component has been separated off. By-products or starting material residues contained in the reaction mixture remain in the reactor and are later obtained with the product and separated off in a separate step.

According to the invention, only part of the template-containing mixture is removed from the reactor. Just enough is removed that the product is still present as a suspension in the reactor so that it can be easily removed from the reactor, for example by pumping it off.

According to the invention, a template is used which is only partially soluble in water. It is of particular advantage if the template is insoluble in polar solvents. This has the advantage that recovery from the condensate is made easier, and time and costs can also be saved here. A simplified separation of the template from the condensate is possible, which can then be carried out for example by means of decanting.

The process according to the invention can be carried out at a pressure of 1 bar to 50 bar, the pressure conditions varying greatly depending on the desired structure of the aluminophosphate. A pressure range between 4 bar and 25 bar is particularly preferred, since the hydrothermal synthesis proceeds optimally under these pressure conditions.

The inventive conversion of the starting materials to aluminophosphates takes place preferably at a temperature of 120.degree. C. to 250.degree. C., the reaction is particularly preferably carried out at a temperature of 160.degree. C. to 200.degree. This has the advantage that the conversion rate is very high at the specified temperatures and the reaction time can be reduced depending on the desired structure.

According to the invention, after the reaction has taken place, the reactor is depressurized while it is still hot and under pressure. This can be done slowly or suddenly via a control unit (valve, regulator, valve, etc.). Depending on the volume of the reactor, the expansion can also take place step-by-step, only so much condensate is collected in another reactor that the product remaining in the reactor is still present as a suspension so that it can be easily obtained from the reactor, by means of pumping or via an outlet valve.

According to the invention, by letting down the reaction mixture in the reactor, more template than water is removed from the reaction mixture. This is given by the lower boiling point of the template component compared to that of the aqueous mother liquor. This means that enough water remains in the reactor so that the product is still present as a suspension. A particular advantage of removing the organic template from the reaction mixture is that the reaction mixture still mainly contains water as waste water. This makes the disposal of wastewater easier, cheaper and, above all, more environmentally friendly.

Depending on the batch size that is implemented in the reactor, about a quarter of the liquid contained therein is removed to about half of the liquid. It is important that the reaction product is still present as a suspension.

In one embodiment of the invention, due to the reaction conditions (high temperatures and high pressures) in the reactor, the expansion of the reactor means that the reaction mixture, containing a template, is collected as an escaping gas in a further reactor and is condensed out therein.

Furthermore, according to the invention, the expansion of the pressurized mixture results in a temperature change, as a result of which the hot, pressurized gas cools and condenses out in the further reactor. The strength and direction of the temperature change depends on the Joule-Thomson effect, which is described by the Joule-Thomson coefficient µJT. The expansion of the exiting gas results in cooling, whereby a solution containing condensate is obtained. With the equation

the Joule-Thomson effect can be described.

Depending on the temperature and the pressure of the condensate in the reactor, the expansion and retention of the condensate can be optimized with the aid of the µJT. While maintaining the enthalpy H, the gaseous condensate can be transferred from a volume V1 at T1 and a pressure ρ1 (in the reactor) to a further reactor in which a volume V2, a temperature T2 and a pressure ρ2 are present. So that the gas cannot build up kinetic energy, a transfer from V1 to V2 takes place through a connection piece between the reactor and the further reactor, via which the condensate-containing gas flows "by itself" through the connection piece to V2 starting from volume V1 due to the pressure ρ1. Volume work is done, with pressure equalization. The amount of energy released ρ1V1 therefore corresponds to the maximum temperature drop that the gas containing the condensate can experience. This also changes the internal energy U of the condensate due to the volume work performed. The work ρ2V2 required for this must be provided by the gas. The conservation of energy is used for this: The internal energy U of the gas changes due to the work performed and due to the law of conservation of energy U1 + ρ1V1 = U2 + ρ2V2. Since the internal energy depends on the temperature, it changes with the change in the temperature T1 and the pressure ρ1 in the reactor with cooling and expansion of the gas to T2 and ρ2. Therefore applies to the Joule-Thomson coefficient

or.

The Joule-Thomson coefficient can assume values μJT> 0 or μJT <0. With positive values, energy is given off to the environment in the form of heat; with negative values, the gas absorbs energy from the environment. In the present case, µJT> 0 must apply so that the gas can cool down and cool down in the further reactor.

By removing the hot, pressurized reaction mixture from the reactor and transferring it to a further reactor, the reactor cools down due to the expansion (Joule-Thomson effect). The mixture can possibly also be actively cooled in that the further reactor is cooled, or, for example, a heat exchanger is integrated, or by active cooling, e.g. Ice bath, dry ice, cold mixtures, etc., of the downstream additional reactor. Such cooling leads to the gaseous, hot reaction mixture cooling down more quickly and a solution of the reaction mixture containing template being obtained more quickly. It is particularly advantageous that the process can be carried out very quickly and therefore there are no long waiting times in the synthesis process before a new synthesis can be started or the remaining reaction mixture can be obtained as condensate.

It is particularly advantageous if the additional active cooling for the cooling process for cooling by the Joule-Thomson effect freezes out the water contained in the condensate. Temperatures from 0 ° C to about -5 ° C are used to freeze out the condensate. Since water already freezes out at higher temperatures (0 ° C), and the organic template contained in it only at lower temperatures, the condensate can be easily and simply separated into template and water, which means that a further separation step is unnecessary because of the freezing out of the condensate, any solids it may contain can also be separated off. However, temperatures that are too low are disadvantageous because at some point too much template is frozen out with it and can no longer be recovered.

The further reactor can be a heatable or alternatively coolable reactor which can be regulated to a certain temperature as a function of the temperature of the gas, so that an optimized condensation of the hot reaction mixture takes place in the further reactor. This can also be provided with a valve so that the gas supply from the reactor can be regulated. Furthermore, this can also have an outlet device such as a tap for the solution. Furthermore, the further reactor can also be connected to a purification device, or be in the form that the further reactor can be used as a separation device, for example a corresponding vessel for a rotary evaporator.

The purification can be carried out using mechanical methods, such as decanting, shaking, separating, distillation, extraction, etc. It is advantageous if the separation is simple, quick and efficient. Chromatography methods such as HPLC, or devices such as e.g. a rotary evaporator can be used, which enables the condensate to be separated with the aid of a vacuum. Further methods which can be used here are known to the person skilled in the art.

Are further purification steps necessary, e.g. To separate any solids, possibly unreacted starting materials, from the template, a further filtration step can take place so that pure template is obtained which is suitable for use in a further synthesis.

According to the invention, the condensate obtained is separated into the individual components. These consist of an aqueous phase and an organic phase which is immiscible or only partially miscible. The water component is separated off, as a result of which very pure template can be recovered, which can be used again without further purification in step a) of the process according to the invention.

According to the process according to the invention, a template that has already been recovered can also be used again and recovered. The number of recovery cycles is not limited. This makes the method particularly favorable, since the amount of fresh template that has to be supplied can be kept low.

Method part:

The methods and devices used are listed below, but these should not be understood as restrictive.

The X-ray diffractograms were measured with an X-ray diffractometer from Pananalytical using CuKα radiation.

The syntheses were carried out in a 2.0 l stirred vessel of type 3 and in an autoclave of the Kiloclave type (10 l) from Büchi AG (Switzerland) with maximum volume.

Embodiments:

The invention is explained in more detail below with the aid of examples that are not to be understood as limiting.

Example 1: Synthesis of AlPO-5 with recovery of template.

AlPO-5 was by means of hydrothermal synthesis starting from a molar gel composition in the ratio of 1.1 TEA: 1.0 Al2O3: 53 H2O: 1.0 P2O5 obtained. Here, 2000 g of the molar gel composition were converted to AlPO-5 at 185 ° C. in a 2.0 l Type 3 stirred vessel from Büchi AG over a period of 12 hours. The pressure in the autoclave was 18 bar. After the starting materials had been successfully converted, the autoclave was opened while still hot and under pressure, and connected to another, ice bath-cooled (0 ° C.), pressure vessel via a hose system. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the pressure vessel. The connection was opened for about 30 minutes so that about 50% of the reaction mixture, predominantly gaseous reaction mixture, escaped. A solution condensed out due to the relaxation and the active cooling through the ice bath. The solution mainly contained TEA, since water and other components only escape from the reactor later. The solution obtained was freed from residues of water by shaking and obtained as pure TEA. The proportion of the recovered TEA agent was 50% based on the amount used. The reaction product AlPO-5 obtained was pumped out of the reactor as a suspension, containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 86%. The product was examined for its crystallinity and purity by means of X-ray diffraction (XRD). It was found that the AlPO-5 obtained in this way had an X-ray crystallinity of 97%. The position of the reflections in the X-ray diffraction pattern clearly shows that AlPO-5 is of good quality and crystallinity.

Example 2: Synthesis of AlPO-5 using recovered template.

AlPO-5 was by means of hydrothermal synthesis starting from a molar gel composition in the ratio of 1.1 TEA: 1.0 Al2O3: 53 H2O: 1.0 P2O5 obtained. 50% of the TEA used was recovered TEA from a previous synthesis of AlPO-5. For the synthesis, 2000 g of the molar gel composition were placed in a 2.0 l stirred vessel of type 3 from Büchi AG at 185 ° C and 18 bar converted to AlPO-5 over a period of 12 h. After the starting materials had been successfully converted, the autoclave was opened while still hot and under pressure, and connected to another, ice bath-cooled (0 ° C.), pressure vessel via a hose system. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the pressure vessel. The connection was opened for about 30 minutes so that about 50% of the reaction mixture, predominantly gaseous reaction mixture, escaped. A solution condensed out due to the relaxation and the active cooling through the ice bath. The solution mainly contained TEA, since water and other components only escape from the reactor later. The solution obtained was freed from residues of water by shaking and obtained as pure TEA. The proportion of the recovered TEA agent was 50% based on the amount used. The reaction product AlPO-5 obtained was pumped out of the autoclave as a suspension, containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 87%. The product was examined for its crystallinity and purity by means of X-ray diffraction (XRD) and compared with an AlPO-5 which was synthesized and obtained only with fresh, unrecovered TEA. It was found that the AlPO-5 obtained in this way, despite the onset of recovered TEA, had the characteristic reflective layers and had an X-ray crystallinity of 98%. The position of the reflections in the X-ray diffraction pattern clearly shows that AlPO-5 is of good quality and crystallinity. The use of recovered TEA in the synthesis of AlPO-5 therefore does not have a negative effect on the product quality.

Example 3: Synthesis of FeAPO-5 with recovery of template.

FeAPO-5 was by means of hydrothermal synthesis starting from a molar gel composition in the ratio of 1.1 TEA: 0.9 Al2O3: 0.2 FeSO4: 53 H2O: 1.0 P2O5. In this case, 2000 g of the molar gel composition were converted to FeAPO-5 at 175 ° C. in a 2.0 l Type 3 stirred vessel from Büchi AG over a period of 12 h. The pressure in the autoclave was 18 bar. After the starting materials had been successfully converted, the autoclave was opened while still hot and under pressure and connected to a further, ice bath-cooled (0 ° C.) pressure vessel via a hose system. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the pressure vessel. The connection was opened for about 45 minutes so that about 50% of the reaction mixture, predominantly gaseous reaction mixture, escaped. A solution condensed out due to the relaxation and the active cooling through the ice bath. The solution mainly contained TEA, since water and other components only escape from the reactor later. The solution obtained was freed from residues of water by decanting and obtained as pure TEA.

The proportion of the recovered TEA agent was 50% based on the amount used. The reaction product FeAPO-5 obtained was pumped out of the autoclave as a suspension, containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 87%. The product was examined for its crystallinity and purity by means of X-ray diffractometry (XRD) and compared with a FeAPO-5 which was synthesized and obtained only with fresh, unrecovered TEA. It was found that the FeAPO-5 obtained had characteristic reflective positions and an X-ray crystallinity of 98%. The position of the reflections in the X-ray diffraction pattern clearly shows that FeAPO-5 is of good quality and crystallinity.

Example 4: Synthesis of FeAPO-5 Using Recovered Template.

FeAPO-5 was by means of hydrothermal synthesis starting from a molar gel composition in the ratio of 1.1 TEA: 0.9 Al2O3: 0.2 FeSO4: 53 H2O: 1.0 P2O5. 50% of the TEA used was TEA recovered from a previous synthesis of FeAPO-5. For the synthesis, 2000 g of the molar gel composition were converted to FeAPO-5 over a period of 12 h in a 2.0 l Type 3 stirred vessel from Büchi AG at 175 ° C. and 18 bar.

After the reactants had reacted successfully, the autoclave was opened while still hot and under pressure and connected to a further, ice bath-cooled (0 ° C.) pressure vessel via a hose system. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the pressure vessel. The connection was opened for about 30 minutes so that about 50% of the reaction mixture, predominantly gaseous reaction mixture, escaped. A solution condensed out due to the relaxation and the active cooling through the ice bath. The solution mainly contained TEA, since water and other components only escape from the reactor later. The solution obtained was freed from residues of water by decanting and obtained as pure TEA. The proportion of the recovered TEA agent was 50% based on the amount used.

The reaction product FeAPO-5 obtained was pumped out of the autoclave as a suspension containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 87%. The product was examined for its crystallinity and purity by means of X-ray diffractometry (XRD) and compared with an FeAPO-5, which was synthesized and obtained only with fresh, non-recovered TEA. It was found that the FeAPO-5 thus obtained, despite the onset of recovered TEA has the characteristic reflective layers and a radiographic crystallinity of 98%. The position of the reflections in the X-ray diffraction pattern clearly shows that FeAPO-5 is of good quality and crystallinity. The use of recovered TEA in the synthesis of FeAPO-5 therefore does not have a negative effect on the product quality.

Example 5: Synthesis of SAPO-34 with recovery of template.

SAPO-34 was by means of hydrothermal synthesis starting from a molar gel composition in the ratio of 1 iso-propylamine: 1 Al2O3: 1 P2O5: 0.4 SiO2: 40 H2O obtained. 2000 g of the molar gel composition were converted to SAPO-34 over a period of 48 hours at 165 ° C. in a 2.0 l Type 3 stirred vessel from Büchi AG. The pressure in the reactor was 15 bar. After the starting materials had been successfully converted, the autoclave was opened while still hot and under pressure and connected to a pressure-proof round-bottom flask which was cooled with an ice bath. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the pressure-tight round-bottomed flask. The connection was opened for about 40 minutes so that about 50% of the reaction mixture, predominantly gaseous reaction mixture, escaped. A solution condensed out due to the relaxation and the active cooling through the ice bath. The solution mainly contained water in addition to isopropylamine. The solution obtained was separated from residues of water by distillation and obtained as pure iso-propylamine. The proportion of the recovered agent isopropylamine was about 50% based on the amount used. The reaction product obtained, SAPO-34, was pumped out of the autoclave as a suspension, containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 90%. The product was examined for its crystallinity and purity by means of X-ray diffraction (XRD). It was found that the SAPO-34 obtained in this way had an X-ray crystallinity of 98%.

Example 6: Synthesis of SAPO-34 Using Recovered Template.

SAPO-34 was by means of hydrothermal synthesis starting from a molar gel composition in the ratio of 1 iso-propylamine: 1 Al2O3: 1 P2O5: 0.4 SiO2: 40 H2O: obtained. 50% of the iso-propylamine used was recovered template from a previous synthesis of SAPO-34. 2000 g of the molar gel composition were converted to SAPO-34 over a period of 48 hours at 165 ° C. in a 2.0 l Type 3 stirred vessel from Büchi AG. The pressure in the autoclave was 15 bar. After the reactants had been successfully converted, the autoclave was opened while still hot and under pressure and connected via a hose system to a pressure-proof round bottom flask which was cooled with an ice bath. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the round bottom flask. The connection was opened for about 40 minutes so that about 50% of the reaction mixture, predominantly gaseous reaction mixture, escaped. A solution condensed out due to the relaxation and the active cooling through the ice bath. The solution mainly contained water in addition to isopropylamine. The solution obtained was separated from residues of water by distillation and obtained as pure iso-propylamine. The proportion of the recovered agent isopropylamine was about 50% based on the amount used. The reaction product SAPO-34 obtained was pumped out of the reactor as a suspension, containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 83%. The product was examined for its crystallinity and purity by means of X-ray diffraction (XRD) and compared with a SAPO-34, which was synthesized and obtained only with fresh, unrecovered isopropylamine. It was found that the SAPO-34 obtained in this way had an X-ray crystallinity of 95%. The position of the reflections in the X-ray diffractogram clearly shows that SAPO-34 is of good quality and crystallinity. The use of recovered iso-propylamine in the synthesis of SAPO-34 therefore does not have a negative effect on product quality.

Example 7: Synthesis of ZSM-5 with recovery of template.

A sodium aluminate solution is prepared from aluminum oxide, NaOH, silicon dioxide, triethylamine and water. The molar composition of the mixture was 80 SiO2: 1 Al2O3: 3.6 Na2O: 7.2 TEA: 1168 H2O. The mixture was stirred until a homogeneous reaction mixture was obtained. The mixture (8 l) was placed in a Kiloclave (10 l) autoclave from Büchi and heated with stirring. The reaction mixture was stirred at a pressure of 15 bar at a temperature of 150 ° C. for 6 h. Then left to stand without further agitation at 150 ° C. until the desired crystallite size of ZSM-5 has been reached. The autoclave was then opened while still hot and under pressure and connected to a steel pressure vessel via a hose system which was cooled with an NaCl / ice bath mixture. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the pressure vessel. The autoclave was opened for about 20 minutes, so that about 50% of the reaction mixture, predominantly the gaseous reaction mixture, escaped. As a result of the relaxation and the active cooling by the ice bath, a solution condensed in the pressure vessel. The solution mainly contained water in addition to triethylamine. The solution obtained was separated from residues of water by shaking and obtained as pure triethylamine. The proportion of the recovered agent triethylamine was about 50% based on the amount used. The resulting reaction product ZSM-5 was pumped out of the autoclave as a suspension, containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 88%. The product was examined for its crystallinity and purity by means of X-ray diffraction (XRD) and with a ZSM-5. It was found that the ZSM-5 obtained had an X-ray crystallinity of 99%. The position of the reflections in the X-ray diffraction pattern clearly shows that the ZSM-5 is of good quality and crystallinity.

Example 8: Synthesis of ZSM-5 Using Recovered Template.

A sodium aluminate solution is prepared from aluminum oxide, NaOH, silicon dioxide, triethylamine (and water. The molar composition of the mixture was 80 SiO2: 1 Al2O3: 3.6 Na2O: 7.2 TEA: 1168 H2O. 50% of the TPABr used was recovered TPABr from a previous synthesis of ZSM-5. The mixture (8 l) was placed in a Kiloclave (10 l) autoclave from Büchi and heated while stirring. The reaction mixture was stirred at a pressure of 15 bar at a temperature of 150 ° C. for 6 h. Then left to stand at 150 ° C without further agitation until the desired crystallite size of ZSM-5 has been reached. The autoclave was then opened while still hot and under pressure, and connected to a steel pressure vessel via a hose system that was cooled with an NaCl ice bath mixture. Upon opening, the pressurized reaction mixture escaped from the autoclave and was collected in the pressure vessel. The autoclave was opened for about 20 minutes, so that about 50% of the reaction mixture, predominantly the gaseous reaction mixture, escaped. As a result of the relaxation and the active cooling by the ice bath, a solution condensed in the pressure vessel. The solution mainly contained water in addition to triethylamine. The solution obtained was separated from residues of water by shaking and obtained as pure triethylamine. The proportion of the recovered agent triethylamine was about 50% based on the amount used. The reaction product ZSM-5 obtained was pumped out of the reactor as a suspension, containing predominantly water, separated from impurities, dried and obtained. The yield based on the non-volatile oxides used was 88%. The product was examined for its crystallinity and purity by means of X-ray diffraction (XRD) and compared with a ZSM-5, which was synthesized and obtained only with fresh, unrecovered triethylamine. It was found that the ZSM-5 obtained in this way had an X-ray crystallinity of 95%. The position of the reflections in the X-ray diffractogram clearly shows that the ZSM-5 is of good quality and crystallinity. The use of recovered triethylamine in the synthesis of ZSM-5 therefore does not adversely affect product quality.

Claims (11)

A process for the preparation of aluminophosphates comprising the steps of a) providing a reaction mixture of an aluminum source, a phosphate source and a template in water, b) reacting the starting materials under hydrothermal conditions in a reactor to form an aluminophosphate, c) releasing the pressure in the reactor and collecting a templated mixture which escapes from the reactor, whereby it cools down under expansion and condenses out, d) separating the template from the mixture, e) returning the template in step a). 2. The method according to claim 1, characterized in that in addition an organic solvent is added to the reaction mixture. 3. The method according to claim 1 or 2, characterized in that the template is used as structure-directing agent. 4. The method according to claim 3, characterized in that the structure-directing agent is an organic nitrogen-containing agent is used, selected from the group consisting of, di-n-propylamine, tripropylamine, triethylamine, triethanolamine, diethanolamine, polyamines, 1,6-hexanediamine, 1,3-propanediamine, piperidine, cyclohexylamine, 2-methylpyridine, N, N-dimethylbenzylamine, N, N-diethylethanolamine, dicyclohexylamine, N, N-dimethylethanolamine, choline, N, N-dimethylpiperazine, 1,4-diazabicyclo [2 , 2,2] octane, N-methyldiethanolamine, N-methylethanolamine, N-methylpiperidine, quinuclidine, N, N-dimethyl-1,4-diazabicyclo [2,2,2] octanion, di-n-butylamine, neopentylamine, Di-n-pentylamine, isopropylamine, t-butylamine, n-butylamine, ethylenediamine, pyrrolidine, 2-imidazolidone, hexamethylimine, 4,4-dimethyl-4-azonia-tricyclo [5.2.2.02,6] undec-8-ene hydroxide OSDA. 5. The method according to claim 4, characterized in that the nitrogen-containing agent is insoluble in polar solvents. 6. The method according to claim 2, characterized in that the template is water-soluble and can be separated by extraction or distillation of water. 7. The method according to any one of the preceding claims 1 to 6, characterized in that the reaction is carried out at a pressure of 1 bar to 50 bar. 8. The method according to any one of the preceding claims 1 to 7, characterized in that the reaction is carried out at a temperature of 50 ° C to 300 ° C. 9. The method according to claim 8, characterized in that the escaping mixture is collected after expansion as the exiting gas in another reactor and condensed. 10. The method according to claim 9, characterized in that the condensate is separated into an aqueous and an organic phase. 11. The method according to claim 10, characterized in that the organic phase of the condensate is reused.