MXPA96005500A - Catalytic composition for the oxidative ozonolisis of alquilpiridi - Google Patents

Abstract

The present invention relates to catalytic composition characterized in that it consists of vanadium, titanium, zirconium and molybdenum oxides having a molar ratio of V2O5 to TiO2 to ZrO2 of 1: 1: 2 to 1:12:25 and having a content of MoO3 of 0.54 to 2.6 weight percent with respect to V2

Description

CATALYTIC COMPOSITION FOR OXIDATIVE AMMONISM OF ALKYL PYRIDINE This invention relates to the catalytic compositions, their use in the oxidative ammonolysis of alkylpyridines and to a process for the production of cyanopyridines.

Preferably, the catalytic compositions are used for the oxidative ammonolysis of 3-methylpyridine and 2-methyl-5-ethylpyridine to the corresponding 3-cyanopyridine. 3-cyanopyridine is an intermediate for nicotinic acid or nicotinic acid amide which are essential B-complex vitamins. Oxidative ammonolysis of alkylpyridines is well known in the art. A great variety of catalytic systems has been described but until now a process that can adequately satisfy the needs of commercial processes on a technical scale has not been known. Reference is made to the certificate of inventors of USSR No. 891 142 which describes a catalyst for the ammonolysis of alkylpyridines consisting of the oxides of vanadium, tin and titanium. The maximum performance REF: 23425 achieved for the conversion of for example 2-methyl-5-ethylpyridine is 63%.

The main disadvantage of this catalytic composition is therefore its low activity and selectivity. From the Swiss patent 595 350, it is further known that 2-methyl-5-ethylpyridine can be converted to 3-cyanopyridine on a supported mixed oxide catalyst composed of vanadium, zirconium or titanium oxides and optionally tungsten. The yields obtained with this catalyst vary between 60% and 75%. This catalyst is also unsatisfactory due to its low selectivity and activity. A further disadvantage is the rather complicated process for producing this supported catalyst.

The object of the present invention is to provide catalytic compositions with additionally improved activity and catalytic performance and therefore to provide an improved process for the oxidative ammonolysis of alkylpyridines especially with respect to their selectivity and yield. The catalytic composition of the present invention according to claim 1 comprises the oxides of vanadium, zirconium, titanium and molybdenum having a molar ratio of V205 to Ti02 to Zr02 of 1: 1: 2 to 1:12:25 and a content of M0O3 from 0.54 to 2.6 weight percent with respect to V2O5.

A preferred catalyst composition has a molar ratio of V2O5 to TiO2 to Z2 from 1: 3: 4 to 1: 8: 16 and an M0O3 content of 0.54 to 1.15 weight percent with respect to V205.

In order to prepare the catalyst composition, the respective oxides can be used alone but it is also possible to use the precursor compounds which are ultimately converted into the oxides. Such precursor compounds are, for example: vanadium oxide, ammonium metavanadate; zirconium oxide, zirconyl chloride, titanium oxide, metatitanium acid, and for molybdenum oxide, ammonium molybdate.

The preparation of the catalyst composition can, as a rule, be carried out by mixing the compounds in a suitable milling device, making granules or tablets with the mixture and finally drying the granules or tablets at a temperature of about 100 ° C to 120 ° C. ° C in a stream of air. The catalyst is advantageously subjected to a thermal treatment in series at temperatures of up to 650 ° C.

The catalyst already prepared can then be charged to the reactor, where after an activation phase under reaction conditions, it is able to show its properties with respect to both, its high activity and selectivity, in large loads of the alkylpyridine and with respect to also to its long lifespan.

The catalytic composition of the present invention is especially suitable for the oxidative ammonolysis of alkylpyridines in the presence of ammonia, an oxygen-containing gas and if necessary water vapor. The preferred application of the catalyst composition is the conversion of 3-methylpyridine or 2-methyl-5-ethylpyridine to 3-cyanopyridine. It has been proven that the following process conditions are adequate.

Air is generally used as the gas that contains oxygen. Thus air offers the advantage that oxygen is already diluted with inert components. The partial pressure of the oxygen can be advantageously regulated by further dilution with a suitable inert gas, for example nitrogen, or by recycling part or most of the deficient gases oxidized.

Two advantages are offered over the state processes of the known material in the conversion of 3-methylpyridine, which according to the invention not only does not require the addition of water vapor, but also uses a practically stoichiometric amount or a small molar excess of ammonia. The gaseous feed of the reagents in the case of the oxidative ammonolysis of 3-methylpyridine is composed of a molar ratio of 3-methylpyridine to ammonia to air (calculated on the basis of oxygen) from 1: 1: 1.5 to 1: 8.5: 60 A preferred gaseous feed is composed of a molar ratio of 3-methylpyridine to ammonia to air (calculated on an oxygen basis) of 1: 1: 2 to 1: 4: 60.

The gaseous feed of the reagents in the case of the oxidative ammonolysis of 2-methyl-5-ethylpyridine is composed of a molar ratio of 2-methyl-5-ethylpyridine to ammonia to air (calculated for O2) and to water vapor of 1 : 20: 20: 60 to 1: 60: 70: 330.

The temperature in the reaction zone of the catalyst bed conveniently varies between 280 ° C and 400 ° C and preferably between 310 ° C and 380 ° C.

The characteristics of the catalytic composition also with respect to the lifetime allow the process to continuously burn on a large scale basis. The maximum yield obtained with 3-cyanopyridine when feeding up to 150 g per liter per hour of 3-methylpyridine catalyst reaches 99%, and with 2-methyl-5-ethylpyridine up to 120 g per liter per hour of catalyst reaches 85 %.

Examples Example 1 A mill of ball 36.4 g of vanadium pentoxide, 48.0 g of titanium dioxide, 197.2 g of zirconium dioxide and 0.42 g of molybdenum trioxide in the molar ratio V2O5: Ti? 2: Zr02 = 1 were crushed and mixed in a ball mill: 3: 8 and 1.15% by weight of M0O3 based on vanadium pentoxide. The mixture was molded in 5 x 5 mm granules and heat treated at a temperature of 100-120 ° C for 6 hours in an air flow. The catalyst obtained in the amount of 60 cm (82 g) was charged to a tubular reactor made of stainless steel (internal diameter of 20 mm, length of 1000 mm). A mixture of the reactants, consisting of 2-methyl-5-ethylpyridine, air, ammonia, water vapor was passed through the catalyst layer at a temperature of 340 ° C. The feed rate (gram per 1 liter of catalyst per 1 hour = 1 h) was: 2-methyl-5-ethylpyridine - 72 g / l_1, air - 1500 liters, ammonia - 228 g "h" and water - 583.3 gl "h ~ corresponding to a molar ratio of 2-methyl-5-ethylpyridine to oxygen to ammonia to water of 1: 47: 45: 108.

Thus, 21.6 g of 2-methyl-5-ethylpyridine were fed for more than 10 hours. The conversion was completed. 15.0 g of 3-cyanopyridine corresponding to a yield of 80.5% of theory were obtained. The total production of 3-cyanopyridine Example 2 a catalyst was used as described in Example 1. A mixture consisting of 3-methylpyridine, air and ammonia was passed through the catalyst at a temperature of 330 ° C. The feed rate (gram per 1 liter of catalyst per 1 hour = gl ~ h ~) was: 3-methylpyridine _ 84 gi '1, air - 2000 liters, ammonia -9.92 gl h corresponding to a molar ratio of 3- methylpyridine: 02: NH3 = 1: 40: 1.3. Thus, 25.5 g of 3-methylpyridine was fed for more than 10 hours. The conversion was completed. 26.8 g of 3-cyanopyridine corresponding to a yield of 95.0 mol% of the theoretical were obtained. The total production of 3-cyanopyridine was 89.2 gl ~ h "1.

Example 3 A catalyst was prepared from 36.4 g of vanadium pentoxide, 64.0 g of titanium dioxide, 98.6 g of zirconium dioxide and 0.2 g of M0O3 in the molar ratio V2? 5: Ti? 2: Zr02 = 1: 4: 4 and 0.54% by weight of M0O3 based on V2O5.

The catalyst was prepared by the method described in Example 1. The gaseous feed consisting of 2-methyl-5-ethylpyridine, air, ammonia and water vapor was passed through the catalyst bed (60 cm) at a temperature of 320. ° C. The feed rate (gram per 1 liter of catalyst per 1 hour = g h) was: 2-methyl-5-ethylpyridine- 72 gl "1h ~ 1 air - 1500 liters, ammonia - 228 gl" 1h ~ 1, water -700 gl -1h-i corresponding to a molar ratio of 2-methyl-5-ethylpyridine:? 2: NH3: H2? of 1: 47: 45: 130. Accordingly, 21.6 g of 2-methyl-5-ethylpyridine were fed for more than 10 hours. The conversion was completed. There were obtained 15.3 g of 3-cyanopyridine corresponding to a yield of 82.2% based on the feeding of 2-methyl-5-ethylpyridine. The total production of 3-cyanopyridine was 50.8 gl "h ~.

Example 4 A catalyst with a molar ratio of V2? S: Ti? 2: Zr? 2 = 1: 4: 4 and 0.90% by weight of M0O3 based on V2O5 was prepared according to example 1. A mixture consisting of 3-methylpyridine , air, ammonia was passed through the catalyst at a temperature of 330 ° C. The feeding speed (gram per 1 liter of catalyst per 1 hour = gl "1 !!" 1) was: 3-methylpyridine - 84 gl "1 !!" 1, air - 2000 liters, ammonia - 9.92 gl "h ~ corresponding to a molar ratio of 3-methylpyridine:? 2: NH3 of 1: 40: 1.3 Accordingly, 25.2 g of 3-methylpyridine were fed for more than 10 hours The conversion was complete. -cyanopyridine corresponding to a yield of 97.9% of the theoretical.The total production of 3-cyanopyridine was 91.0 gl "1!" 1.

Example 5 A catalyst with a molar ratio of V2O5: Ti02: Zr? 2 = 1: 4: 8 and 0.98% by weight of M0O3 based on V2O5 was prepared according to example 1. A mixture consisting of 2-methyl-5-ethylpyridine , air, ammonia and water vapor was passed through the catalyst at a temperature of 320 ° C. The feeding speed (gram per 1 liter of catalyst per 1 hour = gl "h) was: 2-methyl-5-ethylpyridine 72 gl -1h-1, air - 1500 liters, ammonia - 228 gl-1h-1 and water -700 gl -ih-i corresponding to a molar ratio of 2-methyl-5-ethylpyridine: 02: NH3: H20 1: 47: 45: 130. Accordingly, 21.6 g of 2-methyl-5-ethylpyridine were fed for more than 10 hours. The conversion was completed. 15.4 g of 3-cyanopyridine corresponding to a yield of 83% based on the feeding of 2-methyl-5-ethylpyridine were obtained. The total production of 3-cyanopyridine was 51.3 gl "h ~.

Example 6 A catalyst with a molar ratio of V2O5: TiO2: r02 = 1: 4: 8 and 1.15% by weight of M0O3 based on V2O5 was prepared according to example 1. A mixture consisting of 3-methylpyridine, air, ammonia was made pass through the catalyst at a temperature of 325 ° C. The feeding speed (gram per 1 liter of catalyst per 1 hour = gl "1]!" 1) was: 3-methylpyridine - 168 gl "1 ^ 1, air - 2000 liters, ammonia - 22.8 gl h" corresponding at a ratio of 3-methylpyridine:? 2: NÜ3: from 1: 40: 1.5. Accordingly, 50.4 g of 3-methylpyridine were fed for more than 10 hours. The conversion was completed. 55.8 g of 3-cyanopyridine corresponding to a yield of 99.0% of theory were obtained. The total production of 3-cyanopyridine Example 7 A catalyst with a molar ratio of V2? 5: Ti? 2: Zr? 2 = 1: 4: 8 and 1.15% by weight of M0O3 based on VL2O5 was prepared according to example 1. A mixture consisting of 3-methylpyridine , air, ammonia was passed through the catalyst at a temperature of 350 ° C. The feeding speed (gram per 1 liter of catalyst per 1 hour = gl "1 !!" 1) was: 3-methylpyridine - 218 gl "1h" 1, air - 2000 liters, ammonia - 30.35 gl "h" which correspond to a molar ratio of 3-methylpyridine:? 2: NH3 of 1: 16: 1.5. Accordingly, 65.5 g of 3-methylpyridine were fed for more than 10 hours. The conversion was completed. 75.2 g of 3-cyanopyridine corresponding to a yield of 99.0% of theory were obtained. The total production of 3-cyanopyridine was 241.7 gl "^" 1.

Example 8 1. 167 kg of vanadium pentoxide, 2,512 kg of titanium dioxide as metatitanic acid, 6,322 kg of zirconium dioxide and 12.4 kg of ammonium paramolybdate (molybdic acid) in the molar ratio V2Os: Ti02: Zr02 = 1: 4: 8 and 1.05% (NH) Mo O 4H O based on vanadium pentoxide was kneaded in a double-arm kneader and crushed and mixed in a ball mill. The mixture was molded into granules of approximately 3 x 3 mm and heat-treated at a temperature of 100-120 ° C for 6 hours. An amount of the catalyst obtained (1 liter, 1.50 kg) was charged into a tubular reactor made of stainless steel (inner diameter 21 mm, length 3 meters). A reagent mixture consisting of 3-methylpyridine, air, nitrogen and ammonia was passed through the catalyst at a temperature of 340 ° C. The feed rate (gram per 1 liter of catalyst per hour = gl "1h ~ 1) was: 3-methylpyridine - 80 gl ~ h" 1, air - 200 liters h "1, nitrogen 1200 liters h ~, ammonia - 37.5 gl "h ~ corresponding to a molar ratio of 3-methylpyridine to ammonia to oxygen of 1: 2.6: 2.2. Accordingly, 1920 g of 3-methylpyridine was fed for more than 24 hours. The conversion was 99%. 1910 g of 3-cyanopyridine corresponding to a yield of 89% were obtained. The total production of 3-cyanopyridine was 79.6 gl "h ~.

Example 9 An amount of the catalyst obtained from example 8 (985 cm3, 1.46 kg) was charged into a tubular reactor made of stainless steel (internal diameter 21 mm, length 3 meters). A reagent mixture consisting of 3-methylpyridine, air, recycled spent gas and ammonia was passed through the catalyst at a temperature of 345 ° C. The feed rate (gram per 1 liter of catalyst per hour = gf ~ h ") was: 3-methylpyridine 80 gl h", air 180 liters.h ", recycled spent gas 1200 liters.h ~, ammonia 52.5 gl" h ~ which correspond to a molar ratio of 3-methylpyridine to ammonia to oxygen of 1: 3.6: 2.0. Accordingly, 1890 g of 3-methylpyridine were fed for more than 24 hours. The conversion was 98.5%. 1850 g of 3-cyanopyridine corresponding to a yield of 88.5% were obtained. The total production of 3-cyanopyridine was 77 gl "h ~.

Example 10 An amount of the catalyst obtained from example 8 (135 cm, 160 g) was heat treated at 620 ° C for 6 hours. This was loaded into a tubular reactor made of stainless steel (internal diameter 21 mm, length 1000 mm). A mixture of reagents, which consisted of 3-methylpyridine, air, nitrogen and ammonia, was passed through the catalyst at a temperature of 375 ° C. The feeding rate was: 3-methylpyridine 11 gh "(81 gl h = gram per 1 liter of catalyst per hour), air 30 liters. H, nitrogen 285 liters.h", ammonia 4 gh corresponding to a molar ratio of 3 -methylpyridine to ammonia to oxygen of 1: 2: 2.6. Accordingly, 264 g of 3-methylpyridine were fed for more than 24 hours. The conversion was 99%. 261 g of 3-cyanopyridine corresponding to a yield of 89% were obtained. The total production of 3-cyanopyridine was 80 gl "h". l abia 1 Oxidative ammonolysis of 2-methyl-5-ethylpyridine (MEP) 1 1 1 i 4 10 1.15 72 1500 228 583.3 320 100 80 7 50.0 12 4 12 0.54 72 1500 228 700 320 100 79.0 48 9 13 5 16 0.90 76 1500 228 700 320 100 78.5 51 7 14 3 8 0.90 126.6 1500 228 1000 340 100 78.5 85.2 4 8 0.90 134.7 1500 228 1000 360 100 78.0 90.0 16 1 1 6 1.15 72 1500 228 700 320 100 62.0 42.5 17 4 18 090 72 1500 228 700 320 100 74.0 50 8 18 1 6 2 0 54 72 1500 228 700 340 100 67.0 46 0 Table II 19 1 10 8 0.90 84 2000 11.4 325 100 82.0 77.0 1 6 2 0.54 84 2000 11.4 330 100 90.0 84.6 21 4 10 1.15 84 2000 11.4 330 100 94.0 88.4 22 4 12 0.54 84 2000 11.4 325 100 95.0 89.3 23 5 16 0.90 84 2000 11.4 330 100 92.5 86.6 24 4 8 0 90 126 2000 17.1 330 100 99.2 139.9 4 8 090 136 2000 19.7 3501 100 99.0 151.3 It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention, as above, property is claimed as contained in the following

Claims (8)

1. Catalytic composition characterized in that it consists of the oxides of vanadium, titanium, zirconium and molybdenum having a molar ratio of V0s to Ti02 to Zr02 from 1: 1: 2 to 1:12:25 and having an M0O3 content of 0.54 to 2.6 percent by weight with respect to V2Os.

2. Catalyst composition according to claim 1, characterized in that it has a molar ratio of V2Os to Ti02 to Zr02 of 1: 3: 4 to 1: 8: 16 and having an M0O3 content of 0.54 to 1.15% by weight with respect to the V205

3. The use of the catalytic composition according to claim 1 or 2 for the oxidative ammonolysis of alkylpyridines.

4. The use of the catalytic composition according to claim 3 for the oxidative ammonolysis of 3-methylpyridine and 2-methyl-5-ethylpyridine.

5. Process for the preparation of cyanopyridines by the oxidative ammonolysis of alkylpyridines, characterized in that the alkylpyridine together with ammonia, an oxygen-containing gas and if necessary steam is passed through the catalytic composition described in claim 1 or 2 at a temperature from 280 ° C to 400 ° C.

Process according to claim 5 for the preparation of 3-cyanopyridine by the oxidative ammonolysis of 3-methylpyridine, characterized in that 3-methylpyridine, ammonia and an oxygen-containing gas (calculated for 0) in a molar ratio of 1: 1: 1.5 a 1: 8.5: 60 is passed through a catalytic composition as described in claim 1 or 2 at a temperature of 310 to 380 ° C.

7. Process according to claim 6, characterized in that the molar ratio of the 3-methylpyridine, ammonia, and the oxygen-containing gas is from 1: 1: 2 to 1: 4: 60.

8. Process according to claim 5 for the preparation of 3-cyanopyridine by the oxidative ammonolysis of 2-methyl-5-ethylpyridine, characterized in that 2-methyl-5-ethylpyridine, ammonia, an oxygen-containing gas (calculated for 02) and water vapor in a molar ratio of 1: 20: 20: 60 to 1: 60: 70: 330 is passed through a catalytic composition as described in claim 1 or 2 at a temperature of 310 to 380 ° C.