The method of obtaining unsaturated nitriles and the catalyst to obtain

 

(57) Abstract:

The inventive unsaturated nitrile is Acrylonitrile, or Methacrylonitrile, or a mixture obtained by contacting the olefin is propylene, butylene, or a mixture thereof with ammonia and oxygen-containing gas in the vapor phase at a temperature of 300-600oC and at high pressure in the presence of a catalyst corresponding to the empirical formula: MoaBibFecCodNieCrfXgYiOkwhere X is phosphorus, or antimony, or a mixture thereof, Y is an alkaline metal or a mixture, a= 12-14, b= 1-5, C= 0.5 to 5, d, e=0.1 to 6, f=0,1-4, g=0,1-4, i=0,1-2, K - the number determined by the valency of all elements. The catalyst may be supported on a carrier selected from the group consisting of silicon dioxide, aluminium oxide, or their mixture. 2 s and 5 C.p. f-crystals. table 1.

This invention relates to the field of organic synthesis and concerns a method for obtaining unsaturated NITRILES, such as Acrylonitrile and Methacrylonitrile, as well as the catalyst used in this way.

Known methods for producing unsaturated NITRILES by oxidative ammoniuria olefins in the presence of catalysts (see patent USSR N 588906, publ. 1978, and A. S. USSR N 517320, namely Acrylonitrile and Methacrylonitrile, or mixtures thereof by conversion of olefin selected from the group consisting of propylene, isobutylene and mixtures of these substances in the vapor phase at a temperature of from 300o600oC and at high pressure specified olefin with oxygen-containing gas and ammonia in the presence of an oxide catalyst. The method according to the invention differs in that the process in the presence of a catalyst having the following empirical formula:

MoaBibFecCOdNieCrfXgYiOk< / BR>
in which "X" means phosphorus, antimony, or a mixture of,

"Y" means alkali metal or a mixture of,

from 12 to 14,

"b" from 1 to 5,

"C" is from 0.5 to 5,

"d" and "e" are each from 0.1 to 6,

"f" from 0.1 to 4,

"g" is from 0.1 to 4,

"i" is from 0.1 to 2 and

"K" the number determined by the valence of all other elements present.

In the process according to the invention as starting materials it is possible to apply the above olefins in a mixture with paraffin hydrocarbons, such as ethane, propane, butane and pentane. This makes it possible to use ordinary thread refineries without special separation, although the degree of conversion can glared, not having to process harmful effects.

The contacting of the olefin, ammonia and oxygen is preferably carried out in a fluidized bed of catalyst. In principle, the method according to the invention can be carried out continuously, and periodically using equipment of any type suitable for the implementation of catalytic processes in the vapor phase. The catalyst may be in the form of a stationary layer of large particles or in tablet form.

In the method according to the invention can be used with any source of oxygen. For economic reasons it is advantageous to use air as the oxygen-containing substances. The molar ratio of oxygen to olefin in the feed to the reactor, the raw materials should be in the range of from 0.2:1 to 3.0:1, preferably from 1.5:1 to 2.5:1.

The molar ratio of ammonia to olefin in the feed to the reactor feedstock may be from 0.5: 1 to 5.0:1, preferably from 0.9:1 to 1.3:1. The real upper bound for the relationship ammonia: olefin not, however it usually does not exceed 1.3: 1. When ammonia:olefin below the stoichiometric 1:1 can be formed of various oxide derivatives of the olefin. Outside the upper boundary of this area relationships can clicks the pages in this area forms a reduced number of target NITRILES. Within the specified area relations ammonia: olefin observed a maximum degree of conversion of ammonia. Usually neprevyshenie olefin and ammonia recycle back to the reactor.

In some cases, the water in the mixture fed to the reactor, improves the selectivity of the reaction to NITRILES. However, the addition of water in the feedstock is not necessary because the water formed in the reaction mixture during the reaction. Adding water in the source substance molar ratio of water to olefin may be above a 0.25:1, mainly from 1:1 to 4;1, preferably 10:1.

As indicated above, the process temperature is from 300oC to 600oC. Preferably it can be from 380oC to 500oC, particularly preferably from 400oC to 480oC.

The pressure at which carry out the reaction, can be anything, preferably it may be about atmospheric or above, usually from 2 to 5 atmospheres.

The contact time is not limiting, it may be from 0.1 to 50 seconds. The optimum contact time depends on the type of reactive olefin, in General, preferably the contact time is from 1 to 15 seconds.

When implementing the method according to izobretenii. In industrial scale, it is preferable to carry out the process continuously, and recycling the unreacted olefin back to the reactor. Provides for periodic regeneration or reactivation of the catalyst, which may be performed, for example, by treating the catalyst with air at elevated temperature.

The reaction products can be conditioned by any known means. For example, it may be leaching of effluent gases from the reactor with cold water or a suitable solvent for separation of the reaction products. Such fluid to absorb the products of the reaction and neutralization neprevyshenie ammonia can be acidified water. The efficiency of the washing operation can be improved with the use of water as the drilling fluid by adding a wetting agent. In those cases, when the oxidizing agent is used molecular oxygen, the resulting mixture of products after removal from it of NITRILES can be treated to remove carbon dioxide, and the remaining unreacted olefin and oxygen recycle back to the reactor. In the case when the oxygen-containing substance use air, the mixture of reaction products, measures, hydrocarbon fraction for recycling unreacted olefin. In this case, the remaining gases can be neglected. It would also add a suitable inhibitor to prevent polymerization of unsaturated products during regeneration.

Above are empirical formula used in the method according to the invention catalyst. It is a mixture or possibly a complex of the oxides of molybdenum, bismuth, iron, cobalt, Nickel, chromium, phosphorus and/or antimony, or mixtures thereof, one or more alkali metals. Indices in empirical formula corresponding to the content of each component of the catalyst described above. Preferably "o" from 0.75 to 3.0, preferably "Y" means alkali metal other than sodium, preferably from 0.1 to 1.5.

The catalyst according to the invention mainly has a value of specific surface area by BET less than 100 m2/g, preferably from 20 m2/g to 50 m2/,

The catalyst according to the invention can be prepared by any known method. For example, it can be prepared by co-deposition components. Jointly deposited mass can then be dried and ground up for the DAMI. The catalyst can be molded by extrusion into pellets or molding of the balls in the oil. You can also mix the components of the catalyst carrier in suspension with subsequent drying or solutions of their compounds can be impregnated with devices such as silica gel.

Especially resistant to abrasion the shape of the catalyst may be prepared by adding the media to the catalytically active substance in two stages: first prepared and subjected to the heat treatment of the mixture of active catalyst components and up to 60 wt. of the total number of media, and then to powder form thermally treated catalyst add the rest of the media.

The alkali metal can be introduced into the catalyst in the oxide form or in the form of any salt, which, after annealing allows to obtain the oxide. The preferred salts are the nitrates, which are easily accessible and quickly soluble.

Bismuth can introduce the catalyst in the oxide form or in the form of any salt, after calcination which is formed oxide. Preferred water-soluble salts, which are easily dispersed in the mass of the catalyst and after heat treatment which form stable oxides. Most PR is giving nitrate of bismuth in molten metal nitrate.

For the introduction of the iron catalyst can be used any compound of iron, after calcination which is formed oxide. As for other elements, the preferred water-soluble salts due to the ease of their dispersion in the mass of the catalyst with a high degree of homogeneity. The most preferred ferric nitrate.

Similarly, you can enter in the catalyst of cobalt and Nickel.

To enter in the molybdenum catalyst, you can take any of its oxide, for example titanium dioxide, trioxide, pentakis or sesquioxide. Preferred is a salt of molybdenum, capable of hydrolysis or decomposition. The most preferred starting compound of molybdenum for the preparation of the catalyst is heptamolybdate ammonium.

Phosphorus can be introduced into the catalyst in the form of a salt of phosphoric acid, alkaline, alkaline earth metal or ammonium, but preferably the phosphorus in the phosphoric acid. Most preferably, phosphorus, and molybdenum in the form of phosphorus molybdenum acid.

Other items can be entered on the basis of the metal, which is oxidized with an oxidizing acid such as nitric, and then for prigotovlennyh substances as sources of catalyst components according to the invention. Any substance that contains the required components of the catalyst can be used, provided that when heated the total mass of the components of the catalytic mass in the above temperature range, these source materials will decompose to oxides.

The catalyst according to the invention can be used without a carrier. However, it can be done. In this case, it contains from 10 to 90 wt. from the total mass of the catalyst carrier. As a carrier you can use any well-known for these purposes, ingredients: silicon dioxide, aluminum oxide, aluminum silicate, zirconium dioxide, titanium dioxide, alund cuota, silicon carbide, inorganic phosphates such as aluminum phosphate, silicates, aluminates, borates, carbonates, and also substances such as pumice, montmorillonite, etc., i.e. substances which are stable in the conditions of the process.

The media can also add Aerosil. A preferred carrier is silica, which is added to the suspension of the preparation of the catalyst in the form of a Sol of silica or dusty silica. The preferred amount of the carrier in the catalyst is from 40 to 60 wt. from the total mass of the catalyst.

The activity of cat is abode. Typically, the catalytic mass is dried by spraying at a temperature of from 110oC to 350oC and then thermally treated Paladino for from one to twenty four hours or more at a temperature of from 260oC to 1000oC, preferably from 300 to 400 to 550-700oC.

Calcined catalyst can be within shorter time at a higher temperature. How quite a calcination in particular those or other conditions of calcination, determined by testing samples of the substance of the catalyst on the catalytic activity. The calcination is better to perform the camera is open, allowing access of air or oxygen to any amount of oxygen absorbed prokalavaemy mass, could be compensated.

Also used pre-treatment or activation of the catalyst prior to his work with reductant, such as ammonia, in the presence of a limited amount of air at a temperature of from 260oC to 540oC.

The catalyst according to the invention has a high activity upon receipt of unsaturated NITRILES at relatively low temperatures of reaction. He also has an increased service life. In addition, he has as. This catalyst has excellent stability under oxidizing conditions the recovery of the reaction, the underlying method according to the invention. This allows use in a method with a low air-to-olefin and high average hourly feed rate of the feedstock in the reactor. Catalyst provides efficient use of ammonia, which significantly reduces the amount of unreacted ammonia, outgoing wastewater from the reactor. This reduces the amount of sulfuric acid required to neutralize the ammonia in the wastewater.

Thus, the method according to the invention and used in the catalyst allows to improve the work of the section processing the reaction products leaving the reactor, as well as pollution control.

The fact that the reaction in the method according to the invention proceeds at relatively low temperatures, is conducive to enhancing the service life of the catalyst and minimizes the problem of wastewater, for example, allows you to do without afterburning.

However, despite the relatively low reaction temperature, receive a high degree of conversion of the original substances in the NITRILES per cycle 80% and above.

In addition, an important advantage is th its preparation.

The invention is explained in more detail below by examples.

Examples 1 to 8.

The catalysts used in examples of the present invention, were prepared by the method described below.

Example 1.

The nitrates of the metals in the following order were melted together at 70oC 400-ml beaker: Fe(NO3)39H2O (65,08 g), WITH(NO3)26H2O (121,89 g), Ni(NO3)26H2O (65,75), Bi(NO3)35H2O (65,24 g), KNO3(1.63 g)(NH4)6MoO244H2O (GMA) (184,85 g) was dissolved in 300 ml of distilled water followed by the addition CrO3(8,05 g). To this solution was added to the melt of metal nitrates, followed by 40% Zola silica (625 g). The obtained yellow suspension was heated under stirring at 90oC for 3 hours, then the suspension was spray dried. The resulting substance was denitrification at 270oC for 2 hours at 425oC for 2 hours and then was calcined at 580oC for 2 hours in air.

Example 2.

The nitrates of the metals were melted at 70oC 400-ml beaker in the following PEF), Bi(NO3)35H2O (65,20 g), KNO3(1.63 g). GMA (184,91 g) was dissolved in 300 ml of distilled water followed by the addition CrO3(6,24 g ) and 85% H3PO4and 85% H3PO4(1.86 g). To this solution was added to the melt of metal nitrates, followed by 40% Zola silica (625 g). The obtained yellow suspension was heated under stirring at 90oC for 3 hours, then the suspension was spray dried. The resulting substance was denitrification at 270oC for 2 hours at 425oC for 2 hours and was then calcined in air at 580oC within 2 hours.

Example 3.

The nitrates of the metals in the following order were melted together at 70oC 400-ml beaker: Fe(NO3)39H2O (65,1 g), With(NO3)26H2O (121,9 g), Ni(NO3)26H2O (65,6 g), Bi(NO3)25H2O (65,3 g), KNO3(1.6 g). GMA (184,9 g) was dissolved in 300 ml of distilled water followed by the addition CrO3(4.0 g) and 85% H3PO4(4,65 g). To this solution was added to the melt of metal nitrates, followed by 40% silica Sol (625 g). The obtained yellow suspension was heated under stirring at 90oC IS 270oC for 2 hours at 425oC for 2 hours and was then calcined in air at 580oC within 2 hours.

Example 4.

The nitrates of the metals were melted together at 70oC 400-ml beaker in the following order: Fe(NO3)39H2O (65,15 g), Co(NO3)26H2O (122,0 g), Ni(NO3)26H2O (63,3 g), Bi(NO3)35H2O (65,3 g), KNO3(8 g), Cs(NO3) (1.26 g). GMA (185,06 g) was dissolved in 300 ml of distilled water followed by the addition CrO3(a 4.03 g) and 85% H3PO4(4,65 g). The melt of metal nitrates was added to this solution, followed by 40% silica Sol (625 g). The obtained yellow suspension was heated at 90oC for 3 hours, then the suspension was spray dried. The resulting substance was denitrification at 270oC for 2 hours and 425oC for 2 hours and then was calcined at 580oC for 2 hours in air.

Example 5.

The nitrates of the metals were melted together at 70oC 400-ml beaker in the following order Fe(NO3)39H2O (62,21 g), With(NO3)26H2O (116,51 g), Ni(NO3)26H2O (62,68 g), Bi(NO3(of 3.85 g) and 85% H3PO4(4.44 g). To this solution was added to the melt of metal nitrates, followed by Sb2O3(11,22 g) and 40% silica Sol (625 g). The obtained yellow suspension was heated at 90oC for 3 hours, then the suspension was spray dried. The resulting substance was denitrification at 270oC for 2 hours and 425oC 2 hours and then was calcined at 580oC for 2 hours in air.

Example 6.

The nitrates of the metals were melted together at 70oC 400-ml beaker in the following order: Fe(NO3)39H2O (59.3 g), Co(NO3)26H2O (111,0 g), Ni(NO3)26H2O (59,7 g), Bi(NO3)35H2O (59,4 g), KNO3(1.5 g). GMA (168,4 g) was dissolved in 300 ml of distilled water followed by the addition CrO3(3.7 g) and 85% H3PO4(4.2-d). To this solution was added to the melt of metal nitrates, followed by Sb2O3(22,5 g) and 40% silica Sol (625 g). The obtained yellow suspension was heated at 90oC for 3 hours, then the suspension was spray dried. The resulting substance was denitrification at 270oC for 2 hours and 425oC Technorati metals were melted together at 70oC 400-ml beaker in the following order: Fe(NO3)39H2O (62,22 g), With(NO3)26H2O (116,54 g), Ni(NO3)26H2O (60,46 g), Bi(NO3)35H2O ( 62,38 g), KNO3(,78 g) and Cs(NO3) (1.20 g). GMA (176,75 g) was dissolved in 300 ml of distilled water followed by the addition CrO3(of 3.85 g) and 85% H3PO4(4.44 g). To the solution was added to the melt of metal nitrates, followed by Sb2O3(11,22 g) and 40% silica Sol (625 g). The obtained yellow suspension was heated at 90oC for 3 hours, then the suspension was spray dried. The resulting substance was denitrification at 270oC for 2 hours and 425oC for 2 hours and then was calcined at 580oC for 2 hours in air.

Example 8.

The nitrates of the metals were melted together at 70oC 400-ml beaker in the following order: Fe(NO3)29H2O (59.3 g), Co(NO3)26H2O (111,0 g), Ni(NO3)26H2O (57.6 g), Bi(NO3)35H2O (59,4 g), KNO3(0.7 g), and Cs(NO3) (1.2 g). GMA (168,3 g) was dissolved in 300 ml of distilled water followed by the addition CrO3(3.7 g) and 85% H3PO4oC for 3 hours, then the suspension was spray dried. The resulting substance was denitrification at 270oC for 2 hours and 425oC for 2 hours and then was calcined at 580oC for 2 hours in air.

In these examples, the degree of conversion to the unsaturated nitrile is defined as follows.

Mole percent conversion per pass (PEP) in unsaturated nitrile is equal to (moles obtained nitrile product/total moles of olefin converted to all products) x 100.

The reaction of oxidative amination performed in the presence of catalyst compositions prepared by the method of examples 1-8, and using propylene as hydrocarbons, are summarized in Table 1. Each reaction was carried out in a reactor with a fluidized bed volume of 40 cm3. Each catalyst was originally restored by NH3/N2at 440oC for 10 minutes. After a stabilization period of approximately 40 hours samples were collected.

Resulting from the flow reactor was collected in scrubbers bubble type containing a cold solution of HCl. Scorevideo), and composition of the flue gas was determined at the end of the run using a gas chromatograph PerKin-Elmer Model 154, equipped with a gas analyzer with the separation column.

At the end of the mileage of all regeneration wash liquid was diluted to approximately 200 grams with distilled water. A weighted amount of MEK was used as internal standard 50 gram aliquot share diluted solution.

6 Microlitre sample were analyzed in a gas chromatograph 5710 Hewlett-Packard, equipped with a flame ionization detector and rbpk" column. The amount of HCN was determined by titration with AgNO3.

1 1. The method of obtaining the unsaturated nitrile is Acrylonitrile or Methacrylonitrile or mixtures thereof by contacting the olefin selected from the group consisting of propylene, butylene, or a mixture thereof, with ammonia and oxygen-containing gas in the vapor phase at 300 600C and increased pressure in the presence of the oxide catalyst, characterized in that the contacting is carried out in the presence of a catalyst having the following empirical formula MoaBibFecCodNieCrfXgYiOk,1 0;4 k number determined by the valency of all elements.2 2. The method according to p. 1, wherein the process is carried out at 430 S.2 3. The method according to p. 1, wherein the used catalyst supported on a carrier selected from the group consisting of silicon dioxide, aluminium oxide, or their mixture.2 4. The method according to p. 3, characterized in that as the carrier used aluminum dioxide.2 5. The method according to p. 3, characterized in that the number of media is 50% by weight of the catalyst.2 6. Catalyst to obtain unsaturated NITRILES by oxidative aminirovaniya olefins comprising oxygen-containing compounds of molybdenum, bismuth, iron, cobalt, Nickel, phosphorus or antimony, one or more alkali metal, characterized in that it additionally contains chromium and composition of the catalyst corresponds to the empirical formula MoaBibFecCodNieCrfXgYiOk,1 where X is phosphorus or antimony or a mixture thereof;4 Y alkali metal or a mixture thereof;a 4 12 14;4 b 1 5;4 c 0,5 5,0;4 d, e 0,1 6,0;4 f 0,1 4,0;4 g 0,1 4,0;4 i 0,1 2,0;4 k the number determined by the valency of all elements.2 7. The catalyst p. 6, characterized in that it further comprises a carrier selected from the group comprising silicon dioxide, aluminium oxide or cm

 

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