CS259886B2 - Method of synthetic modified material preparation on base of silicon dioxide and boron trioxide - Google Patents

Description

The invention relates to a process for preparing a synthetic modified material for; silica and boron dioxide.

With respect to the prior art, they are mentioned in the literature. various natural compact borosilicates, i.e., non-porous materials, in which the boron may be either in a planar or in a tetrahedron configuration. Various porous glasses are also known which are obtained by chemical attack of glassy materials. Depending on their odor, these materials may contain silica, alkaline substances, alumina and also barium oxide B2O3. However, up to now, it has not been possible to introduce boron into a zeolite structure, i.e., a crystalline structure with regular porosity as reported in the literature, see, for example, Breck, Zeolite Molecular Sieves, J. Wiley & Sons, New York, 1974, p. 322.

Only the procedure in which zeolites are impregnated with boric acid is known from the prior art. formed of aluminum and silicon oxides, as disclosed in U.S. Patent No. 4'049,573. In this case, boron does not become an integral part of the crystal lattice.

Also known is a process for the preparation of a synthetic modified silica base material of the general formula:

0.0001 - 1 Mn 0 _m . 1 SiO2 where M 'O _m is an oxide of one or more metals used as chemical elements modifying silica selected from the group consisting of chromium, beryllium, titanium, vanadium, manganese, iron, cobalt, zinc, zirconium, rhodium, silver, tin , antimony and boron. The process is carried out in an aqueous, alcoholic or aqueous-alcoholic solution by reacting a silica derivative or a tetraalkyl orthosilicate with a derivative of said modifying element having at least partially amphoteric character in the presence of a clathrating agent selected from the group consisting of tertiary amines, aminoalcohols and quaternary ammonium bases, optionally in the presence of minerals? a binder selected from the group consisting of alkali and alkaline earth metal hydroxides and halides and optionally in the presence of an inorganic base. This mixture is processed in a sealed environment for a period of up to 30 days at a temperature in the range of from 100 to 220 ° C and then processed in a conventional manner.

The essence of the process for the preparation of a synthetic modified material based on silica and boron oxide of the general formula:

(0 - 1) R ₂ O (0 - 1 C _{2 / n} O. B2O 3. X S ₁ O 2 in which

R is a portion of an used organic base from the group of tetraalkylammonium or nitrogen cations. amine-derived.

C is a cation such as H ⁺ , NH4 ⁺ or a valence metal,

X 'is a number equal to or greater than 4, preferably up to 1000; according to the invention, characterized in that the silica derivative is reacted; or a tetraalkyl orthosilicate with a boron derivative such as an acid. boronates, trialkyl borate, borates, in the presence of a chelating agent selected from the group consisting of tetraalkylammonium compounds and amine function compounds, under hydrothermal conditions in a closed environment at a pH in the range of from 1 to 5%. 9 to 14 and a temperature of 110 to 220 ° C for 1 to 30 days, optionally in the presence of a mineralization; an agent selected from the group consisting of hydroxides and halides of alkali metals and alkaline earth metals, the substance obtained is filtered, washed, dried and calcined at a temperature ranging from 400 to 90.0 ° C.

In a preferred embodiment of the invention, the silicon derivative is an organic silicon derivative, the boron derivative is an organic boron derivative, and it is also preferred that ethylphenediamine is used as the chelating agent.

The advantages of the process according to the invention are that, in this process, substances are obtained which are very stable both under the action of high temperatures and under the action of steam. The materials obtained according to the invention can be advantageously used for various catalytic reactions and for adsorption processes.

According to the present invention, a process has been found. in which bor. except that. it can, in addition, be able to form silicon, new materials having a crystalline, porous structure that can be defined and related to the zeolite structure.

The materials obtained by the process of the present invention, hereinafter referred to as "grants" for the sake of simplicity, can be characterized in their desirable form by the following composition:

(i0 - 1.) RzO. (0-1) C ₂ / _n O. B2O3. x SiQz in which it confuses.

R is an organic base product used to prepare this boralite,

C is a cation, for example H ⁺ , NH4 ⁺ or a metal cation of valency n,

x. is a number greater than or equal to 4, preferably greater than 1,000, and the values are different for each type. Improved thermal stability of these materials is achieved at higher SiQ2 / B2Q3 ratios.

It should be noted that in the state k.dy. when the boralite has been subjected to calcination (or annealing), the proportion of R20 in the final material in some cases, but not always, does not occur.

Of the boralites corresponding to the above general formula, in particular four types were synthetically prepared, hereinafter referred to as boralite A, boralite B, horalite C and boralite D, these boralites having a defined crystalline structure and their X-ray diffraction patterns corresponding to H ⁺ forms calcined at high temperatures (in the range of 450 to 750 ° C) they exhibit the distinctive lines specified in Tables I to IV below.

The presence of other cations instead of H ⁺ causes minor changes in spectrum, similar to conventional zeolites.

The infrared spectra show a characteristic band which depends on the amount of boron present and ranges from 910 to 925 cm ^-1 .

As mentioned above, the process for preparing boralites is based on the reaction of a silicon derivative, a boron derivative and a suitable chelating agent, under hydrothermal conditions at a pH of from 9 to 14, at a temperature of from 100 to 220 ° C and from 1 to 30 days.

Boralities of high purity can be prepared by a process using organic boron and silicon derivatives, such as trlalkyl borates and tetraalkyl ortho-silicates, and by performing a hydrothermal treatment in a Teflon or polypropylene, platinum or similar material, ensuring that the alkaline solution did not extract various impurities from the crystallization vessel.

The absence of impurities guarantees special properties of the final product, such as the hydrophobic character and the resulting loss of dehydration ability.

In cases where high purity is not absolutely necessary, cheaper raw materials can be used, for example in the case of boron. faorite, sodium borate and borax, and, in the case of silicon, colloidal silica, silica gel, sodium silicate, aerosol, and other materials, glass containers, stainless steel, and the like can be used for crystallization.

In this case, the boralities may contain impurities originating from the reactants or from the crystallization vessel. Commercially available silica contains, for example, up to 2,000 ppm of alumina, but it has been shown that alumina up to 10,000 ppm does not alter the structural and crystallographic properties, although other properties, such as hydrophobic character and ability dehydration.

As chelating agents, compounds containing amino, ketone, alcohol, acid and other functional groups can be used, and alkyl-alkali bases such as tetraalkylamino-6 hydroxides are most suitable. The choice of these compounds together with the choice of reactants has a decisive influence on the final form of the boralites.

In addition, a mineralizing agent such as an alkali metal or alkaline earth metal hydroxide or halide may be used.

Boralite A can be characterized in the anhydrous state by the following molar ratios of the individual oxides present:

(0 - 1) RaO: (0 - 1) C _{2 / n} O: B2O5:

: (8—30) S1O2 where is

R tetramethylammonium cation (TMA cation),

C can be H ⁺ , NH & lt ^; t ⁺ or a metal cation of valency n.

The X-ray diffraction pattern of the substance obtained by calculating Bonality A, in the H ⁺ form, has prominent lines, which are characterized in Table 1 below.

Boralite B can be characterized in the anhydrous state by the following molar ratios of the individual oxides present:

(0-1) R2O: (0-1) C _{2 / n} O: B2O3:

: (5-50) SiO2 where it means

R tetraethylammonium cation (TEA cation),

C may be H ⁺ , NHi ⁺ or a metal cation of valency n.

The X-ray diffraction pattern of the compound obtained by calcination of boralites-B, in the H ⁺ form, has the marked lines shown in Table 2 below.

Boralite C can be characterized by the following molar ratios of the individual oxides present in the anhydrous state:

[0 — 1] R20: (0-1) C11 _/ O: B2O3:

: (4—1000) S1O2 where it means

R is a tetraethylammonium or tetrapropylammonium or amine-derived nitrogen cation such as ethylenediamine,

G can be H ⁺ , NH 4 ⁺ or a metal cation of valency n.

In the following examples, in the embodiment of Example 5, this boron-modified silica is prepared, which corresponds to the boralite composition C specified above. The X-ray diffraction pattern of the substance obtained by calcination of boronite C in H ⁺ form has the marked lines shown in Table 3 below.

Boralite D can be characterized in the anhydrous state by the following molar ratios of the individual oxides present:

(0 - 1) RzO: (0 - 1) C, _{/ n} O: B2O3:

: (4-20) S1O2 where is

239888

R tetrabutylammonium cation ,,

C is H ⁺ , NH ' ¹ ' or a metal cation of valency n.

The X-ray diffraction pattern of the compound obtained by calcination of boralite -D in H- ⁺ form has the significant lines shown in Table 4 below.

Borality ¹ are very stable substances, as already mentioned, and Io only at high temperatures but also in the presence of steam.

These boralities prepared according to the process of the present invention, in particular boral A1. B, C and D can be used for catalytic reactions or adsorption processes, and these borates can be used as such in a prepared form or dispersed on a more or less inert carrier material, preferably in accordance with the invention. of the invention will be selected from the group consisting of silicas, aluminum oxides and clay materials. These compounds can be used for a variety of reactions, as will be illustrated and illustrated in the Examples.

In the following, practical examples of the process according to the invention are intended to illustrate the process without further limiting the scope of the present invention. Practical examples of the use of the materials prepared by the process of the invention will also be appended.

Example 1

This example will illustrate the preparation of Boralite A.

In a glass vessel (pyrex glass) maintained under carbon dioxide-free atmosphere, 132 grams of a 25% aqueous solution of tetramethylammonium hydroxide (concentration by weight) was charged to which 18.6 grams were added with stirring. boric acid.

After complete dissolution, 187.5 grams of tetraethyl orthosilicate was added with stirring.

The reaction mixture was then heated to 60 ° C with stirring, gradually forming a white, milky precipitate. Ethanol resulting from the hydrolysis of tetraethyl ortho-silicate was continuously removed.

After 12 hours, the alcohol was completely removed, after which 0.18 g of potassium hydroxide and distilled water were added to a total volume of about 300 ml. At this stage, the reaction mixture was transferred to a static autoclave lined with teflon and the hydrothermal treatment was then started at 145 ° C for 12 days. The product was allowed to cool to room temperature, collected on a filter, washed thoroughly with distilled water, and then dried at 120 ° C.

The product thus obtained consisted of crystals with an average size of approximately 0 ^ 1 to 0.5 'μτα ·.

A portion of the sample thus obtained was calcined at 750 ° C.

The product obtained can be characterized by the molar ratio of SiO2: B2O3 = 11. The X-ray diffraction pattern of the H ⁺ form corresponds to the data given in Table 1.

The infrared spectrum showed a characteristic band for mountains, which does not occur in conventional zeolites, in the region of 921 cm ^-1 .

Example 2

In this embodiment, the process of preparing boralite A using colloidal silica is illustrated.

In this example, the procedure was as in Example 1, including the order of operations, in which 210 grams of a 25% by weight tetramethylammonium ammonium oxide solution, 27 grams of boric acid IhBO: and 240 grams of colloidal oxide were placed in a glass vessel (pyrex glass). 40% by weight of silica.

The mixture was stirred for Γ hour while warming to 80 ^{° C} and then placed in a 1 liter titanium autoclave with a stirring unit. The hydrothermal treatment was carried out for 10 days at a temperature of 150 ° C and at a pressure that formed spontaneously in an autoclave.

This above process was obtained crystalline * product, which was collected on a filter ^1, washed, dried and calcined for 6 hours * při'teplotě 750 ° O. This product showed a X-ray diffraction pattern as shown in Table 1 below and an infrared band in the region of 917 cm ^-1 .

In addition, this product had the following characteristics:

actual-density 2,19 g / cnr ³ · (helium-method), acidity (pH pH 2,4 cesium ') * ratio · STOzu B2O5 12,3

Example 1 a-d 3 ’·

In this example, the process for preparing a porous crystalline boralite type * B will be illustrated.

According to this example, the conditions were the same as those used. in Example 2, 11 grams of a 25% by weight tetraethylammonium hydroxide solution, 12 grams of boric acid and 100 grams of a 40% colloidal silica solution were reacted.

Hydrothermal treatment was according to · the present example conducted for 9 days at teplotě- ^15D ° C Velim static autoclave for objemu- * ^{300! I} ml '· which was lined with Teflon. ¹

The result obtained is: The product ¹ after filtration, washing, drying and calcination consisted of spherical particles having an average diameter of 1.3 µm.

The product thus obtained showed a molar ratio of SiO2: B'O; - ~ 6.86. The X-ray spectrum of the H ⁺ form which was subjected to calcination at 550 ° C corresponded to the data in Table 2 below. The infrared spectrum showed a characteristic band at 921 mi ^-1 ,

The specific surface area, determined by nitrogen using the BET method, was 421 m² ^. / g, the pore volume was 0.18 cm-Vg, the actual density (helium method) was 2.32 g / cm ³ , the acidity (measured by the cesium chloride method) corresponded to a pH of 1.8.

Example 4

This Example illustrates the preparation of Horalite C. Following the same procedure as in Example 1, 90 grams of a 25% by weight tetrapropylammonium hydroxide solution, 37.5 grams of boric acid, 125 milliliters of distilled water, and the reaction is reacted. 62.4 grams of tetraethyl cricosilicate.

The mixture thus prepared was treated in a hyurothermal manner in the same autoclave used in Example 3 at 160 ° C for 11 days. After conventional processing into a h ⁺ form, the product particles had an olive shape with an average dimension ranging from 10 to 15 gm and a diffraction pattern corresponding to the values shown in Table 3 below. The infrared band appeared in the region of 920 cm ^-1 and the SiO2 ¹ : B2O3 molar ratio was 4.

Example 1 and 4 5

In this example, the same procedure was used as in Example 4, with 37.5 grams of orthoboric acid, 250 milliliters of water, 3 grams of potassium hydroxide, 180 grams of 25 wt% tetrapropylammonium hydride solution, 5 grams of potassium bromide respectively. and 124.8 grams of tetraethyl ortho-silicate.

Then, the mixture was placed in an autoclave of the same procedure as in Example 2, with a hydrothermal treatment carried out for 6 days at 175 degrees Celsius. After the usual processing into the H ⁺ form, a spherical particle product was obtained whose X-ray diffraction pattern corresponded to Horality C, and this X-ray diffraction pattern is shown in Table III. The infrared band appeared at 915 cm @ ¹ and the SiO2: B2O3 molar ratio was 11.2.

The actual density (as determined by the helium method) was 2.36 g / cm ³ , the specific surface area (determined by BET with nitrogen) was

377 m ² / g, pore volume 0.18 cm ³ / g and pore diameter ranging from 0.5 to 3 nm.

Example 6

In this example, the same procedure was used as in Example 4, with 30 grams of tetramethyl ortho-silicate, 14.6 grams of triethylborate, 1100 grams of water, 80 grams of tetrapropylammonium hydroxide (25% by weight) and 2 grams of potassium hydroxide respectively. . Crystallization was carried out for 6 days at 190 ° C, washing and subsequent operations were the same as in Example 4.

The X-ray spectrum of the H ⁺ form, calcined at 550 ° C, corresponded to the horality C, which is characterized in Table 3. The SiO 2: B 2 O 3 molar ratio was 17 and the BET specific surface area was 380 m ² / g.

Example 7

The preparation of boralite C will be illustrated in this example. The procedure was as in Example 4, with 130 grams of tetra-chloroboronate being reacted respectively. 15 grams of rotting acid, 250 milliliters of water, 70 grams of tetrapentylammonium hydroxide in 250 milliliters of water and 5 grams of potassium hydroxide in 50 milliliters of water.

The mixture was stirred at 60-80 ° C for 24 hours and then transferred to a 1 liter titanium autoclave equipped with a stirrer and treated for 12 days at 165 ° C. The product, calcined at 550 ° C, showed a X-ray diffraction pattern corresponding to Boirality C, which is shown in Table 3.

The SiO ² : B2O 3 molar ratio was 13.9. Example 1

The preparation of boralite C is illustrated in the same manner as in Example 4, with 88.7 grams of tetraethylammonium hydroixide (20 wt% solution), 4.15 grams of boric acid H3BO3 being reacted. 62.5 grams of tetraethyl ortho-silicate. Ethanol was distilled off from the clear solution thus obtained at 60-80 ° C without observing gel formation. The resulting mixture was. transferred to a 250 ml stainless steel autoclave, where the hydrothermal treatment was carried out for 10 days at 150 ° C.

Under the above conditions, a com259886 creamy gel was formed, which was suspended in 100 ml of distilled water, after which 2.5 grams of potassium hydroxide was added and the mixture was heated to 80 ° C with stirring, the water was evaporated and the volume adjusted to 250 milliliters. This process can optionally be repeated until the milky appearance of the gel is achieved.

The gel was again transferred to an autoclave for 15 days at 175 ° C, following the same procedure as in Example 4.

The X-ray diffraction pattern of the H ⁺ form of the product, calcined at 550 ° C, corresponded to the data in Table 3 below that corresponds to Borality C.

The SiO2: B2O3 ratio in the final product was 12.1.

Example 9

This example will illustrate the process of preparing boralite C from ethylenediamine.

In the same manner as in Example 2, 4.25 grams of sodium hydroxide, 120 milliliters of water, 6 grams of boric acid H3BO3, 85 grams of ethylenediamine and 50 grams of 40% by weight colloidal silica were reacted.

The hydrothermal treatment was performed at 175 ° C for 9 days in a 300 ml Teflon-lined autoclave.

The X-ray diffraction pattern of the H ⁺ form of the product, calcined at 550 ° C, corresponded to the data in Table 3 corresponding to Borality C. The S1O2: B2O3 molar ratio in the thus prepared product was 11.3.

Example 10

This procedure illustrates the preparation of Boralite D. Using the same procedure as in Example 1, 225 grams of a 40% by weight tetrabutylammonium hydroxide solution, 20 grams of boric acid, 200 grams of tetraethyl orthosilicate are reacted, 0.2 g of potassium hydroxide and, after distilling off the ethanol, distilled water was added to make up the volume to 1 liter.

The hydrothermal treatment was carried out in a titanium autoclave equipped with a stirrer for 12 hours at 165 ° C.

The thus obtained crystalline product in H ⁺ form, calcined at 550 ° C, was analyzed, with a diffraction pattern corresponding to borality D as shown in Table 4 below. The infrared spectrum showed a band at 919 cm ^-1 , which is characteristic of bor. The specific surface area (determined by BET by nitrogen) of this product was 415 m ² / g and the pore volume was 0.18 cm ³ / g.

The molar ratio of S1O2: B2O3 for this product was 4.8.

Example 11

In the same manner as in Example 10, 113 grams of 40% by weight tetrabutylammonium hydroxide, 10 grams of boric acid and 75 grams of 40% by weight colloidal silica were reacted.

The hydrothermal treatment was carried out for 12 days at 150 ^° C in a teflon lined autoclave.

The product thus obtained, which was in crystalline H ⁺ form, calcined at 550 ° C, had a molar ratio of S1O2: B2O3 of 10.4, and further showed the diffraction pattern of X-rays shown in Table 4. Infrared the spectrum showed a characteristic band at 918 centimeters ^-1 .

The specific surface area (determined by the BET method with nitrogen) of this product was 335 m ² / g and the pore volume corresponds to 0.155 cm ³ / / εν further examples will illustrate the use of synthetic modified silicon dioxide and boron oxide based materials reaction.

Example 12

This example will illustrate the use of a synthetic modified silica-boron dioxide material obtained by the process of the present invention for the conversion of methyl tert-butyl ether.

3 milliliters of boralite A catalyst, prepared as described in Example 1, having a sieve passed through a sieve having a mesh size ranging from 19 to 100 per cm ² was charged into an electrically heated tubular reactor having an internal diameter of 8 millimeters.

Methyl tert-butyl ether was metered into the reactor using a metering pump, which was preheated by passing through a preheating zone.

A pressure control valve, calibrated to a pressure of 0.6 MPa, was placed downstream of the reactor, with an appropriately heated sampling device, which, after reducing the pressure, made it possible to feed the reactor effluent to the gas chromatographs.

Methyl tert-butyl ether was fed at the temperatures given in Table 5 with a flow rate of 6 cm ³ / h, i.e. the space velocity of the liquid phase was 2 h ^-1 . The results obtained are shown in Table no.

5.

5 9 8 8E

Example 13

The procedure was as in Example 12, with 3 milliliters of a boralite B catalyst prepared in Example 3 having a sieve having a mesh size of 100 to 400 per cm ² was charged into the same reactor. Thereafter, the same procedure as in Example 12 was carried out at a pressure of 0.6 MPa and the results shown in Table 6 below were obtained.

Example 14

This procedure was carried out in the same manner as in Example 12, with 2 milliliters of boralite C catalyst prepared as described in Example 4 having a mesh size of 6-19 mesh per cm ² was charged into the same reactor. In the same manner as in Example 12, methyl tert-butyl ether was fed for several hours to determine the constant catalytic activity during the process.

The process was carried out in a reactor at a temperature of 150 ^DEG C. and at a pressure of 0.6 MPa, the space velocity of the liquid phase being 2 h ^-1 . The results obtained are shown in Table 7 below.

Example 15

In this example, the same procedure was carried out as in Example 12, with 3 milliliters (i.e. 1.35 grams) of boralite D, prepared as described in Example 10, having a sieve having a mesh size ranging from 100 to 400 per cm ² .

Methyl tert-butyl ether was fed under the conditions outlined in Table 8 below, which also provides the results of this procedure.

§ •• Table 1

Boralite type A

Interplanar distance d (nm) Relative intensity

0,882 M 0.825 WITH 0,652 M 0.612 M 0,56.1 MW 0.532 W 0.442 MW 0.427 MW 0.409 MW 0.409 MW 0.402 MW 0.392 MW 0.383 M 0.347 W 0.342 W 0.327 MW 0.288 W 0.274 W 0.247 W

Comment:

VS - very strong S - strong

MW - moderate W = weak

With the change in the molar ratio of Sia: B2O3, the cation, slight changes in the calcination temperature of the calcination and the nature of the values present are observed.

Table 2

Boralite type B

Interplanar distance d (nm)

Relative intensity

1,123

0,652

0.598

0.408

0.390

0.346

0,326

0.305

0.298

0.265

0.205

WITH

W

W

MW

WITH

MW

MW

W

MW

W

W

Comment:

VS - very strong S ~ strong

MW = moderate W = weak

With the change in the SiO2: B2O3 molar ratio, the calcination temperature and the character of the cation present, slight changes in the tabulated values can be observed.

Table n. 3

Boralite type G

Interplanar distance d (nim) Relative intensity

1,109 VS 0.994 WITH 0,987 MW 0,666 W 0,633 MW 0.596 MW 0.567 MW 0.555 MW 0.533 W 0.500 W 0.495 w 0.458 w 0.434 w 0.424 MW 0.398 W 0.383 WITH 0.380 with 0.373 MW 0.370 M 0.363 MW 0.346 W 0.342 W 0.333 W 0.329 W 0.323 W 0.303 MW 0.297 MW 0.293 W 0.272 W 0.259 W 0.248 W 0.241 W 0.238 W 0.200 MW 0.198 MW

Comment:

VS - very strong § ~ t ~~ sílria.

MW - moderate W = weak,

18 «

With the change, the ratio of S1O2: B2O3, the sludge temperature observed a slight change in the tabulated hours and the character of the cation present can be noted.

,. _; , _ř; '^^^^ aWTatoulka No. 4

Boralite type D

Intorplanar distance-d (nm) Relative intensity

1,112

1,000

0,667

0,636

0.597

0.556

0.499

0.459

0.434

0.383

0.370

0.362

0.346

0.333

0,304

0.297

0.250

0,248 '

0,200 '

VS

WITH

W

W

M

MW

MW

W

W

WITH

M

W

W w

w

MW

W

W

MW

Comment.

VS - very strong S = strong

MW = moderate W = weak

With a change in the molar ratio of S1O2: B2O3. a slight change in the tabulated values can be observed in the calcination temperature and the nature of the cation present.

Table 5 ^:

Catalyst: boralite type A pressure: 0.6 MPa liquid phase space velocity: 2 h ^-1

Number- experimental Temperature reactor (TC) Conversion of methyl tert-butyl ether (%) :, Acquired metlsaíMol ·. ' (%) Acquired isobuten (%) 1 200 14.5. 99.9 99.8 2 ' 225 22.7 99, .9 .. 99 *, 8 3 275 71.7 99 ', 8 99 ⁴ , 8 ' 4 305 99.1 99.7 99; 7 5 315 99.9. 99.7 99.7

Table 6

Catalyst: Boralite type B

pressure: 0.6 MPa Number attempt Temperature reactor (° C) Spatial speed (h-i) Conversion methylterc.- of butyl ether (%) Acquired methanol (%) Acquired isobutene ( ^10O / o) 1 160 2 93.7 99.8 99.3 2 170 2 99.3 99.1 99.0 3 170 4 98.2 99.6 99.1 4 150 4 96.1 99.9 99.6

Table 7

Catalyst: Boralite type C pressure: 0.6 MPa space velocity: 2 h ^-1 reactor temperature: 150 ° G

The attempt number

Conversion of methylterc.

Butyl ether (° / o)

Acquired imethanol (%)

Acquired isobutene (%)

Time interval (h)

1 1 97.6 99.7 99.4 2 2 95.9 99.9 , 99.5 3 5 96.9 99.9 99.6 4 24 94.5 99.9 99.6 5 25 96.8 99.9 99.7 6 26 95.8 99.9 99.7 Table 8 Catalyst: Boralite type D pressure: 0.6 MPa Number Temperature Spatial Conversion Acquired Acquired attempt reactor speed methylterc.- methanol isobuten (° C) (h-i) of butyl ether (%) (%) (%) 1 136 2 96.3 99.9 99.9 2 136 4 75.3 99.9 99.9 3 150 4 96.5 99.9 99.8

OBJECT OF INVENTION

Claims (4)

A process for preparing a synthetic modified silica-boron oxide-based material of general formula (0-1) R 20. (0-1) C _{2 / n} O.B ₂ O ₃ x S ₁ O ₂ in which it represents R is a portion of an used organic base from the group of tetraalkylammonium cations or an amine-derived nitrogen cation C is a cation H ⁺ , NH 4 + or a metal with a valency of n, x is a number equal to or greater than 4, preferably up to 1000, characterized in that the silicon dioxide or tetraalkyl orthosilicate derivative is reacted with a boron derivative, such as boric acid, trialkyl borate, borates, in the presence of a chelating agent selected from the group consisting of tetraalkylammonium and amine-function compounds, under closed hydrothermal conditions at a pH of between 9 and 14 and at a temperature between 110 and 220 ° C, for 1 to 30 days, optionally in the presence of a mineralizing agent selected from the group consisting of alkali and alkaline earth metal hydroxides and halides, filtered, washed, dried and calcined at a temperature in the range of 400 to 900 ° C. 2. The process of claim 1 wherein the silicon derivative is an organic silicon derivative. 3. The method of claim 1, wherein the boron derivative is an organic boron derivative. 4. The process of claim 1 wherein the chelating agent is ethylenediamine.