DE2150832A1 - Pyridine prodn - from acetaldehyde, ammonia and oxygen in vapour phase - Google Patents

Abstract

The reaction is carried out 300-550 degrees C in the presence of a condensation catalyst, pref. silica-alumina Picoline and higher condensation products formed besides pyridine are demethylated by oxidation so that the pyridine yield is increased. Methanol or isobutyraldehyde can be introduced into the mixture.

Description

Manufacture of pyridine The manufacture of pyridine and picolines conventionally takes place from a reaction mixture, the acetaldehyde, formaldehyde and ammonia, using suitable catalysts, the aldehydes represent the carbon source. As the commercial demand for pyridine increases is than that after Picolinen, it consequently makes economic sense that one tries to increase the pyridine-picoline product concentration in favor of pyridine.

Furthermore, considering the price of formaldehyde, it would be very advantageous to the need to bypass the use of formaldehyde or replace it with a to replace less expensive reactants. Of course, there could be even bigger economic ones Advantages are realized when unused portions of the reactants are used as substitutes serves for formaldehyde, recovered and in the cycle the subsequent ones Mixtures of reactants could be fed back. This is the case with the present not to practice conventional syntheses that make use of formaldehyde, and this constraint entails a considerable loss to industry.

According to the present invention, the aforementioned disadvantages become and other similar evils which will come to light have been overcome. These and a number of other advantages over the currently known technique can be seen more clearly from the following description.

According to the invention, pyridine is produced by adding acetaldehyde, ammonia and oxygen at elevated temperatures in the presence of a condensation catalyst implemented.

The condensation of these reactants is in a vapor phase and preferably in the presence of an inert diluent such as steam or nitrogen gas, or both, executed. The term "oxygen" as used herein is intended to like air also a considerable proportion of nitrogen-containing air, which is naturally as an inert diluent acts.

Under normal circumstances, that is, without the addition of oxygen or Air, the product mixture contains very little, if any, pyridine. Essentially then only 2-, 3-, 4-picoline together with higher condensation products, such as the Methyläthylpyridinen (MEP), formed, The presence of oxygen in the reaction mixture causes in situ oxidative demethylation of the picolines and the NEP on pyridine.

According to a second embodiment II of the present invention will Acetaldehyde, methanol and ammonia in the presence of oxygen or air among the conditions just given above, in which methanol is not present, co-condensed. The formaldehyde reactant currently used in the synthesis of pyridine is, as stated by the Ifand, replaced by the much cheaper methanol.

naturally oxidizes and demethylates that present in the reaction milk Oxygen in situ the picolines Ilnd higher condensation products that together be formed with pyridine. In contrast to the situation when using formaldehyde In addition, any unused ethanol can easily be recovered and be used again in the cycle. This, of course, means an essential one Savings.

According to a further embodiment III of the present invention acetaldehyde, ammonia, oxygen and isobutyraldehyde are among those given above Conditions converted to pyridine, with isobutyraldehyde being the more expensive Formaldehyde replaces and the oxygen reactant in situ replaces the picolines and higher condensation products, which are formed in addition to pyridine, demethylated by oxidation. This becomes natural the pyridine yield is significantly increased.

The embodiments II and III, which have just been described, are also best in the presence of an inert diluent such as N2, water vapor and the like. Although these are the preferred diluents belong to other inert diluents helium, argon and the like, as well as saturated hydrocarbons such as .iethan, athan, propane, etc.

The reaction according to any of the embodiments described above works best in the presence of a silica-alumina type rondensation catalyst carried out. Catalysts for the reactions according to the invention are generally suitable are the prior art aldehyde-ammonia condensation catalysts. To-typical aldehyde-ammonia condensation catalysts in the literature of the prior art are described include clays, silicas, silicic acid clays, Metal oxides such as ZrO2, MgO, TiO2, ThO2, CuO, ZnO, PbO and the like. Preferred However, the silica-alumina catalysts, which are either 13 or 25% by weight Al203 and 87 or 75 wt.% SiO2, and with other substances, in particular Oxides and fluorides are 'tged'. Such doping substances include zinc oxide, ZrO2, ThO2, BaO, CuO, lead oxide, cadmium oxide, MgO and fluoride, such as ZnF2, PbF2, CdF2, IIP, NH4F and the like. Other aldehyde-ammonia condensation catalysts im For the purposes of the present invention, the crystalline aluminosilicates, e.g. zeolites of the faujasite and itordenite families, occurring naturally or synthetically the latter also known as "molecular sieves".

Although temperatures range from about 300 ° C to about 550 ° C for all reactions of the invention are suitable, will give the best results in a temperature range of about 350 ° C to about 500 ° C. Though very Good results can be achieved at atmospheric pressure, negative or positive pressures with a corresponding reduction or

Increase in temperature can be applied.

Discussed below are those reactant ratios which for embodiment I of the present invention, that is, the acetaldehyde, Ammonia and oxygen reaction in the presence of an inert diluent, best fit. The ranges are based on the ole of each reactant and the inert one The following diluents per ol acetaldehyde reactant: Ammonia: about 0.2 to about 15.0 moles / mole acetaldehyde; Oxygen: about 0.1 to about 5.0 moles / mole Acetaldehyde; inert diluent: about 1.0 to about 25.0 moles / mole acetaldehyde.

If air is used instead of pure oxygen, the Amount of air used is regulated so that the oxygen-to-acetaldehyde molar ratio remains in the above range of about 0.1 to about 5.0 moles. The preferred molar amounts of reactants per mole of acetaldehyde are the following: Ammonia: about 0.5 to about 5.0 moles; Oxygen: about 0.2 to about 2.5 moles; inert diluent: about 1 to about 10.0 moles.

It is generally preferred that the molar concentration of the acetaldehyde in the total gaseous material that flows over the catalyst, about 30 to about Does not exceed 40%.

The residence time of the reactants over the catalyst can depend on on the temperature, the flow rate and whether the catalyst is in the fixed bed or the fluidized bed form, vary widely. In general residence times in the range from about 1 to about 60 seconds are used and at a fixed bed catalyst, the preferred range is between about 1 and about 15 seconds.

In the embodiment II of the present invention, that is the acetaldehyde, methanol, ammonia, oxygen (air) and inert diluent system, are the moles of each reactant used per mole of acetaldehyde in the following ranges: ammonia: about 0.2 to about 15 moles; Methanol: about 0.1 up to about 20 moles; Oxygen: about 0.1 to about 5.0 moles; inert diluent: about 1 to about 25 moles.

If air is used instead of pure oxygen, the The amount of air used is regulated in such a way that the oxygen-to-acetaldehyde molar ratio remains in the above range of about 0.1 to about 5.0 moles. If the invention carried out at high methanol levels, it is often expedient to do so in the absence of added diluent, such as steam or nitrogen, to work. The preferred molar amounts of the reactants per mole of acetaldehyde are as follows: Ammonia: about 0.5 to about 5.0 moles; Oxygen: about 0.2 to about 2.5 moles; Methanol: about 0.25 to about 5.0 moles; and inert diluent: about 1 to about 10.0 Mole.

When working in the absence of an inert diluent, the preferred concentration of ethanol is in the range of about 1 to about 15 moles per mole of acetaldehyde.

In embodiment III, i.e. the reaction of acetaldehyde, Isobutyraldehyde, ammonia and oxygen (air) in the presence of an inert diluent, are the moles of each reactant used per mole of acetaldehyde in the the following areas: Ammonia: about 0.2 to about 15 moles; Oxygen: about 0.1 to about 5.0 moles; Isobutyraldehyde: about 0.25 to about 10.0 ol; and inert Diluent: about 1 to about 25 moles.

If air is used instead of pure oxygen, the The amount of air used is regulated in such a way that the oxygen to acetaldehyde molar ratio remains in the above range of about 0.1 to about 5.0. The preferred molar amounts of the reactants 3e moles of acetaldehyde are the following: Ammonia: about 0.5 to about 5.0 moles; Oxygen: about 0.2 to about 2.5 moles; Isobutyraldehyde: about 0.5 to about 2.5 moles; and inert diluent: about 1 to about 10.0 Mole.

As with the above-mentioned embodiment I, it is also with the embodiments II and III generally prefer that the molar concentration of acetaldehyde in the total gaseous material that flows over the catalyst, about 30 to about Does not exceed 40%.

The residence time of the reactants over the catalyst can be a function the temperature, the flow rate and whether the catalyst is in the fixed bed or the fluidized bed form is used, vary widely.

In general, residence times will range from about 1 to about Applied for 60 seconds and a fixed bed catalyst is the preferred range between 1 and 15 seconds.

In most cases, the order in which the reactants are added is not critical. In order to prevent the reactor from blocking, it is advisable to remove the aldehydes and preheat the ammonia to at least about 200 ° C before mixing. In general will the diluent (N2, water vapor, etc.) before mixing mixed with the ammonia with the aldehyde. When using water vapor as a diluent is used, it is appropriate to use an aqueous acetaldehyde solution as the charge (Embodiment I) or an aqueous solution of acetaldehyde and methanol as a feed (Version II) to be used. In embodiment III, in which the butyraldehyde and water are not miscible, it is advisable to use a mixed acetaldehyde / Use isobutyraldehyde feed and the water to the vaporized acetaldehyde / isobutyraldehyde stream to be added in the form of steam. After mixing the diluent, the aldehyde (and the methanol) becomes with ammonia at about 200 0C or above the combined gaseous mixture is then preheated to the reaction temperature and at a point just below the catalyst bed with the preheated oxygen (Air) mixed. The escaping gases are after going over the catalyst flowed, condensed into liquid form and analyzed by conventional methods.

Before the ingredients are mixed, the catalyst becomes ordinary for about 1 hour while a very slow flow of oxygen (air flow) over it flows, heated to the reaction temperature map. Immediately before letting the Aldehyde vapor leaves the ammonia together with the slow oxygen (air) stream Flow over the catalyst.

For a better understanding of the examples below and It is best to look at the types of catalysts used and tables gets to know the process of their production. The catalysts are through the Letters A to M designated.

Catalyst A 297 g of 70% HNO3 became a warm solution of 472.5 g NaSiO3.9H2O in 2 liters of water are added (part I). 134.0 g Al (NO3) 3 9H20, which in Excess water was dissolved with a solution of 3.65 g of zinc oxide about 15 ccm of 70% HN03 added (part II). For the manufacture of the catalyst the solution representing Part II (see above) quickly became with good agitation added to the warm, part I (see above) solution. After thorough Mixing the two parts, the whole solution was treated with NH4OH solution until until the pHz value of the solution had reached 9.5. After thorough mixing The resulting batch was allowed to settle and the precipitate then became filtered off.

After filtering, the solid became thoroughly two or three times washed with water and dried at 200 ° C. for 3 hours. The dried material was then calcined for 4 hours at 500 oC.

Catalyst B A solution was added to 33 g of catalyst P which contained 4.8 g of 49% HF solution in 125 cc of H20. After soaking for 4 hours, the solution sucked off and the catalyst washed with water and 16 hours dried at 125 ° C.

Catalyst C This catalyst is made by heating the catalyst B prepared for 16 hours in an oven regulated at 475 oC.

Catalyst D This catalyst was prepared by adding 168.53 g Silica clay (mesh size: 10/20; type 980, sold by the Davtson company Chemical Division of W.R. Grace & C °.) Containing 13% clay to one Solution of 14.54 g of 49% HF solution in 160 ccm of H2O was added.

The mixture was left to soak at room temperature for 3 hours stand long. After excess liquid was suctioned off, the catalyst became Heated to 165 ° C. overnight.

Catalyst E To 942 g pellets of silica-alumina (grade 980; 15% clay) that were 5.175 mm (1/8 ") in size became a solution of 106.5 g of a 49% HF solution in 550 ccm H20. After soaking for 6 hours at room temperature the excess liquid was poured off and the catalyst for 16 hours dried at 110 ° C. The dried catalyst was then 6 before use Calcined for hours at 525 ° C.

Catalyst F To 223 g pellets of silica-alumina (grade 980; 15% clay), which were 3.175 mm in size, became a solution of 55 g of Pb (OOCCH3) 2: 3H2O given in 175 ccm H20. The catalyst was stirred for 1/2 hour, the excess Liquid was suctioned off and the catalyst was dried at 120 ° C. for 1 hour. A solution was added to the dried catalyst containing the lead acetate of 21.0 g of NH4F in 175 cc of H20. After 5 minutes of agitation under reduced Pressure was poured off the excess solution, and the pellets were washed with water Washed free of soluble salts. After drying overnight at 120 ° C calcined the pellets for 5 hours at 450 ° C.

Catalyst G This catalyst was made from Catalyst A as follows prepared: 22.2 g of catalyst A were quickly added to a solution Contained 1.90 g of 49% HF in 65 cc of water.

After standing at room temperature for 2 1/2 hours, the excess became The liquid was poured off and the catalyst was dried in the oven at 125 ° C., then was the catalyst is heated in an oven at 475 ° C. for 4 hours.

Catalyst H 6R3 g silica-alumina (mesh size: 10/20; Davison variety 980) containing 13% alumina was quickly added to a solution that was 5.95 g of 49% HF solution in 70 ccm of water. After standing for 5 hours at At room temperature, the excess liquid was poured off and the catalyst dried in an oven at about 1? 5 0C. Before its use was the catalyst in the reactor at the reaction temperature for 0.5 to 1.0 hours below one pre-treated with slow airflow.

Catalyst I 5), 58 g of silica-alumina (mesh size: 10/20; Davison variety 980), which contained 25 ffi clay, were quickly added to a solution which 4.6) g of 49% HF solution in 60 cc of water. The drying and catalyst pretreatment were the same as described under Catalyst H.

Catalyst K This catalyst was prepared in 2 parts as follows produced: Part 1 To 103.2 g of silica-alumina (mesh size: 10/20; Davison variety 980), which contained 25% alumina, a solution was added, the 6.5) g of 49% HF solution in 110 cc of water contained. After standing for 4 days at The excess liquid and the catalyst were decanted at room temperature Dried at 165 ° C. for 3.5 hours. After drying, the catalyst Calcined at 460 ° C. for 16 hours.

Part 2 To 81.2 g of the catalyst prepared in Part 1 was a Clear, filtered solution of 29.85 g of ZrO (NO3) 2.2H2O in 155 ccm of water. Man let the system stand for 1 hour at room temperature and then removed the Water using a rotary evaporator while the flask is in vacuum was gently heated. After finally drying for 48 hours at 130 ° C the impregnated catalyst was calcined at 450 ° C. for 6 hours.

Catalyst L 54.3 g silica-alumina (10/20 mesh; Davison variety 980) containing 13% alumina was added to a solution containing 3.1 g of 49% HF and 3.4) g Cu (NO3) 2.3H2O, dissolved in 50 ccm of water. The Co / HF solution was left soak the catalyst for 5 hours with occasional agitation.

After decanting the excess liquid, the catalyst became Dried for 16 hours at 165 ° C and then calinated for 5 hours at 455 ° C, Catalyst M 50.0 g of silica-alumina (10/20 mesh; Davison variety 980), the Containing 15% clay were added to 100 cc of a solution containing 5.0 g of thallium (I) acetate in 75 cc ethanol / 25 cc water. Then as long as NH4OH solution added until the solution turned brown. The solution was then heated in vacuo removed to 85 to 90 ° C. After drying for 16 hours at 150.degree. C., the catalyst became Calcined for 2.0 hours at 500 ° C.

The present invention is best illustrated by the following examples understandable, which in the case of a special and detailed description only are intended to be representative and not to unduly limit the scope of the invention should.

Examples 1-15 The reactor used for these experiments was a 2.54 cm (1 inch) inside diameter, 15.24 cm long tube made of stainless steel with threads on both ends. That used as a catalyst Material was halfway in the reactor tube between two layers of glass beads inserted. The reactor was capped with threads cut into it and let them screw on both ends, locked. At one end The reactor had 2 opposing inlet holes drilled, and a third one Hole for the effluent was drilled at the other end. The reactant vapors were mixed outside and flowed through one of the two inlet openings directly into the bottom part of the reactor. The second inlet opening at the bottom of the reactor was used for the supply of hot oxygen (air). The reactor was through Immersion in a suitable heating medium kept at the desired temperature. In Table I below, embodiment I of the invention is used of the reactor just described.

Table 1 Synthesis of pyridine and picolines from acetaldehyde and Ammonia gas flow rates (STP) * temp. Mol / hour / 15 cc catalyst At- ° C catalyst AcH ** H2O NH3 air clearance analyzer 1 425 A 0.03769 0.2827 0.093 0.0493 2 425 A 0.03769 0.2827 0.0493 0.0830 5 425 À 0.02756 0.2067 0.0627 0.068 4 425 B. 0.02756 0.2067 0.0627 0.068 5 425 B 0.01798 0.1798 0.1017 0.068 6 425 B 0.0220 0.220 0.066 0.066 7 425 B 0.01786 0.1786 0.0761 0.0456 8 425 B 0.01505 0.1505 0.07522 0.07522 9 425 C 0.01505 0.1505 0.0451 0.1053 10 425 C 0.01505 0.1505 0.07522 0.07522 11 588 D 0.015 0.150 0.075 0.075 12 420 D 0.015 0.150 0.075 0.075 15 450 D 0.015 0.015 0.075 0.075 14 423 D 0.015 0.150 0.060 0.090 15 42n D 0.01627 0.1627 0.0325 0.1175 T a b e 1 1 e I - Continued yield in «x temp.

At ° C catalyst pyridine 2-picoline 3- and 4-game picoline 1 425 A 8.5 11.9 9.7 2 425 A 5.0 12.6 10.2 3 425 A 7.0 17.7 16.3 4 425 B 10.6 17.4 14.4 5 425 B 12.9 15.1 12.7 6 425 B 11.7 15.1 12.5 7 425 B 8, o 21.9 19.2 8 425 B 12.4 15.4 14.0 9 425 C 15.6 4.8 4.3 10 425 C 13.6 14.95 13.6 11 388 D 12.0. 12.1 11.4 12 420 D 7.8 15.3 22 13 450 D 3.1 12.7 19.35 14 423 D 9.6 12.3 14.65 15 423 D 13.1 ), 28 3.83 Yield: Calculated as the carbon utilization in mol%, i.e.

that the yield is the percentage of the total carbon in that Load goods that are based on the assumption that the other products are not be formed, ultimately in, every product device. Based on a stoichiometry, according to which either 1 mole of pyridine or 1 mole of picoline is formed from 3 moles of acetaldehyde, is the theoretical maximum yield (i.e. carbon utilization) for formation of pyridine 5/6 or 83.3%. The corresponding maximum value for each picoline is 100%.

** AcH = acetaldehyde + STP = normal temperature and pressure.

Examples 16-18 In Examples 16-18 below Table II, which further illustrates Embodiment I, is pure oxygen used instead of air. It became the same reactor as the one above Table I was used, but the procedure was changed as follows: One liquid mixture of acetaldehyde and water was released at a known rate evaporated and pure oxygen was using just before entering the reactor mixed with the hot vapors. The heated ammonia passed through the second inlet port entered the bottom part of the reactor and mixed with the oxygen, water vapor and acetaldehyde vapors before flowing over the catalyst. The Aell, H20 and NH2 flows were kept constant; and the oxygen flow was changed. Man let the process run continuously and withdrew from the different Oxygen levels each have an aliquot for analysis.

Table II Gas flow rates (STP) moles / hour / 40 ccm catalyst at- temp. catalyst game ° C sator ACH H2O NH3 O2 16 400 E 0.05194 0.5194 0.2597 0.0463 0.05194 0.5194 0.2597 0.060 0.05194 0.5194 0.2597 0.070 17 400 F 0.05194 0.5194 0.2597 0.005) 5 0.05194 0.5194 0.2597 0.0154 0.05194 0.5194 0.2597 0.0268 0.05194 0.5194 0.2597 0.0402 0.05194 0.5194 0.2597 0.0535 0.05194 0.5194 0.2597 0.067 18 400 E 0.05194 0.5194 0.2597 0.0402 0.05194 0.5194 0.259Y 0.0555 0.05194 0.5194 0.2597 0.067 0.05194 0.5194 0.2597 0.0803 0.05194 0.5194 0.2597 0.1071 T a b e 1 1 e II - continued yield in% * at temp. Kataly- Pyridine 2-Picoline) - and 4-Picospiel ° C sator lin 16 400 E 26.3 6.5 5.85 28.96 2.48 3.9 24.58 1.15 1.7 17 400 F 0.7 33.65 28.25 7.83 21.98 20.94 18.36 11.67 12.31 23.3 6.66 7.85 23.7 3.67 5.25 17.92 1.58 1.62 18 400 E 5.05 17.45 20.83 10.81 12.38 13.43 17.82 7.87 10.0 21.38 5.18 6.90 28.22 2.78 2.73 * Yield Calculated as carbon utilization in mol%, i.e.

that the yield is the percentage of all carbon in the Pressing load on the assumption that the other products are not are formed, ultimately into every product. Based on a stoichiometry, according to which either 1 mole of pyridine or 1 mole of picoline is formed from 5 moles of acetaldehyde, is the theoretical maximum yield (i.e. carbon utilization) for formation on pyridine 5/6 or 83,)%. The corresponding maximum value for each picoline is 100 %.

Examples 19 to 36 These examples illustrate the embodiment II. A liquid charge mixture containing acetaldehyde, methanol and water, is evaporated and with a controlled flow rate over a condensation catalyst passed, which is maintained at an elevated temperature. It became the one for them Examples 1 to 15 (see above) described reactor used, only that the evaporated Charge mix before being brought into contact with the heated catalyst became, was further mixed with a hot gas stream of ammonia and air. The reaction products are condensed in a flask cooled with ice water and according to conventional Methods analyzed. The reaction conditions are given in Table III below specified.

Table III Gas flow rates (STP) moles / hour / 15 ccm catalyst at temp.

clearance ° C AcH H2O MeOH NH3 Air 19 423 0.01527 0.1374 0.01527 0.0775 0.0775 20 423 0.01527 0.1374 0.01527 0.0775 0.0775 21 423 0.01527 0.07634 0.07634 0.07634 0.07634 22 423 0.01527 0.07634 0.07634 0.07634 0.07634 23 390 0.01527 0.07634 0.07634 0.04581 0.1069 24 378 0.01386 0.1237 0.01386 o, o693 o, o693 25 400 0.01386 0.1237 0.01386 0.04158 0.09702 26 378 0.01386 0.1237 0.01386 0.04158 0.09702 27 350 0.01386 0.1237 0.01386 0.04158 0.09702 28 350 0.01386 0.1237 0.01386 0.04158 0.09702 29 350 0.01386 0.1237 0.01386 0.04158 0.09702 30 350 0.01414 0.0707 0.0707 0.0424 0.0989 31 378 0.01414 0.0707 0.0707 0.0424 0.0989 32 350 0.01637 0.00 0.1512 0.0796 0.0477 33 378 0.01687 0.00 0.1558 0.0796 0.0477 34 378 0.01687 0.1518 0.01566 0.05145 0.1200 35 378 0.01386 0.1237 0.01386 0.0693 0.0693 36 378 0.01386 0.1237 0.01386 0.0693 0.0693 T a b e l l e III - continued with- cata- 100 x moles of product, which is produced in 3.0 hours. Yield in% * game lysa is won, for pyridine 2-picoline 3- and not around- pyridine 2-picoline 3- and 4-pico- Set 4-picoline in methanol in% 19 G 0.4728 0.1127 0.122 not measured 17.2 4.92 5.33 20 H 0.6973 0.0667 0.1304 "" 25.37 2.90 5.7 21 H 0.8216 0.0184 0.345 "" 12.8 0.34 6.45 22 J 0.8354 0.029 0.224 "" 13.0 0.54 4.2 23 J 1.04 trace 0.256 "" 16.2 lane 4.8 24 D 0.5612 0.1622 0.1251 13.9 23.6 8.18 6.31 25 D 0.5321 0.0156 0.0621 5.6 21.74 0.77 3.04 26 D 0.6118 0.0768 0.0657 12.6 25.68 3.87 3.31 27 D 0.4884 0.080 0.0435 40.35 22.7 4.45 2.42 28 J 0.4354 0.1463 0.0450 38 20.0 8.07 2.48 29 K 0.3927 0.1436 0.0553 44.9 18.5 8.12 3.13 30 K 0.603 0.177 0.114 61.8 18.2 6.43 4.12 31 K 0.732 0.129 0.132 36.8 16.7 3.5 3.62 32 K 0.3688a 0.1686a 0.096a 49.5 9.63 5.28 3.0 33 K 0.583b 0.100b 0.1184b 17.7 7.88 1.63 1.92 34 L 0.434 0.0292 0.0362 15.4 18.48 1.49 1.85 35 L 0.418 0.1695 0.1327 12.26 17.47 8.5 6.65 36 M 0.4745 0.129 0.0866 24.3 20.7 6.76 4.53 * Yield: The percent yields for Examples 19 up to and including 23 are, as defined in Tables I and II (see above), calculated as percent carbon utilization and based on the total number of Acetaldehyde and methanol contain carbon atoms that are actually the reactor are supplied, related. In Examples 24 to 36 inclusive are the Yields have been calculated based on the total amount of acetaldehyde that the Reactor was fed, together with only that amount of methanol that actually was consumed, was obtained. Based on a stoichiometry, according to the 2 mol Acetaldehyde react with 1 mole each of methanol and ammonia, is the theoretical Yield (carbon utilization) of pyridine 100%.

(a) 100 x moles of product generated in 2.0 hours.

(b) 100 x moles of product generated in 2.5 hours.

Examples 37-40 These examples were carried out essentially as in the examples 16 to 18 (see above) carried out, only that the charge Methanol was also contained acetaldehyde and water, the other reaction conditions are given in Table IV below.

Table IV Example Temp. Gas Flow Rates (STP) Catalyst No. ° C mol / hour / 40 ccm catalyst AcH H2O MeOH NH3 O2 37 400 0.0482 0.482 0.0241 0.24 0.0268 F 0.0536 38 400 0.04812 0.4812 0.024 0.2406 0.0133 F 0.0268 F 0.0401 39 400 0.045 0.45 0.09 0.24 0.0134 E 0.0268 0.0402 0.05356 0.067 0.0803 40 400 0.0508 0.4812 0.0221 0.240 0.402 E 0.0535 0.067 0.0803 T a b e l l e IV - Continuation of example 100 x moles of product, which in recovered, yield in% * No. 1.0 hours generated were unreacted methanol in% pyridine 2-picoline 3- and pyridine 20 picoline 3- and 4- 4-picoline lin 37 0.4088 0.2301 0.222 13.5 23.2 15.7 15.2 0.4945 0.0665 0.0991 9.61 27.9 4.5 6.71 38 0.304 0.321 0.30 13.17 16.72 15.62 0.336 0.260 0.28 14.62 13.87 14.6 0.616 0.101 0.143 26.9 5.3 7.52 39 0.198 0.103 0.135 48.5 10.62 6.62 8.71 0.3616 0.143 0.204 41.6 12.4 5.9 8.38 0.5616 0.1179 0.2105 46.2 19.8 4.98 8.90 0.7816 0.0726 0.198 44.2 27.2 3.03 8.27 0.884 0.0547 0.238 38.9 29.8 2.21 9.64 0.694 0.0449 0.142 36.6 23.1 1.8 5.68 40 0.294 0.1795 0.1255 48.9 13.02 9.53 6.67 0.614 0.0992 0.147 36.3 26.55 5.15 7.63 0.689 0.0439 0.100 36.7 29.8 2.27 5.2 0.662 0.0297 0.0678 32.2 28.4 1.52 3.49 * Yield: Calculated as in the case of Examples 24 to 36 (see above); compare the footnote, which follows Table III, Example 41 A mixture with a l: l molar ratio of isobutyraldehyde (i-BuH) and acetaldehyde (AcH) is known with Speed passed through a preheater, and the resulting ones are called Aldehydes are mixed with known amounts of water vapor, air and ammonia in such a way that that the molar ratio NH / aldehyde 5: 1, the molar ratio air / aldehyde 10: 1 and that Molar ratio of water vapor / aldehyde 10: 1. The mixture is then at 470 ° C passed over a silica-alumina-zinc oxide-HF catalyst in such a way that the Residence time over the catalyst is in the order of 7 to 8 seconds. The products are collected at 0 ° C. and analyzed by gas chromatography. the Results of the experiment are shown in Table V below.

T a b e l l e V At gas flow rate (STP) 100 x moles of product, which was generated in game temp. mol / hour / 50 ccm catalyst 1.75 hours ° C AcH iBuH H2O NH3 Air Pyridine 2-Picoline 3- and 4-Picoline 41 470 0.06275 0.06275 0.6275 0.6275 0.6275 0.310 0.280 0.81 At temp. Yield in% * game ° C pyridine 2-picoline 3- and 4-picoline 41 470 2.35 2.55 7.37 * The yield is as the carbon utilization in percent based on the total amount of carbon fed to the reactor (AcH + i-BuH), calculated.

From the above examples in Tables I to V including it can be seen that the embodiments I, II and III of the present Invention very effective ways of producing pyridine in substantial percentages Yields without the need to use formaldehyde can be opened. Using of methanol (cf.

Embodiment II) improve those recovered in a substantial amount Proportion of unconverted methanol for recirculation the economy and performance of the present invention is considerable when compared with the Compares the evils that arise when using formaldehyde as a reactant.

For those skilled in the art it is obvious that when performing Changes and modifications can be made to the present invention, without the spirit of the invention and of course without the scope of the invention, as defined in the appended claims.

Claims (1)

P a t e n t a n s p r u c h e Verf method for the production of pyridine, characterized in that that you get acetaldehyde, ammonia and oxygen in the presence of a condensation catalyst Reacts at elevated temperatures and the resulting pyridine wins, wherein said oxygen in situ picolines and higher condensation products that together formed with pyridine, oxidatively demethylated, so that the pyridine yield is improved. 2. The method according to claim 1, characterized in that methanol added to the reaction mixture. 5. The method according to claim 1, characterized in that isobutyraldehyde zupetzt the reaction mixture. 4. The method according to claim 1, characterized in that an inert Diluent is present in the reaction medium. 5. The method according to claim 4, characterized in that the inert The diluent is water vapor. 6. The method according to claim 1, characterized in that the condensation catalyst is an aldehyde-ammonia catalyst. 7. The method according to claim 6> characterized in that the The condensation catalyst is a silica-alumina catalyst. 8. The method according to claim 1, characterized in that the Implementation can take place in a vapor phase. 9. The method according to claim 1, characterized in that the reaction temperature is in the range of about 300 ° C to about 550 ° C, 10. The method of claim 1, characterized in that the reaction temperature is in the range of about 350 ° C up to about 500 ° C. 11. The method according to claim 2, characterized in that one does not converted methanol wins and can be recycled. 12. The method according to claim 1, characterized in that the ammonia concentration about 0.2 to about 15.0 moles per mole of acetaldehyde and the oxygen concentration about 0.1 to about 5.0 moles per mole of acetaldehyde. 13. The method according to claim 2, characterized in that the ammonia concentration about 0.2 to about 15.0 moles per mole of acetaldehyde, the concentration of oxygen about 0.1 to about 5.0 moles per mole of Aceta) denyd and the methanol concentration about 0.1 to about 20 moles. 14. The method according to claim 3, characterized in that the ammonia concentration about 0.2 to about 15.0 moles per mole of acetaldehyde, the oxygen concentration about 0.1 to about 5.0 moles per mole of acetaldehyde and the isobutyraldehyde concentration about 0.25 to about 10.0 moles.