JPH0136826B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 3-picoline. Pyridine base is an important intermediate in the chemical industry, for example in the production of nicotinic acid or nicotinamide. Various methods for producing pyridine base are known. 2-Methyl-5-ethylpyridine is currently produced on a large scale from acetaldehyde or paraldehyde and ammonia in the presence of a wide variety of catalysts, such as ammonium salts, by fluid-phase processes. As a by-product, 2
- and 4-picoline are not formed at all. 2- and 4-picolines are currently produced from acetaldehyde and ammonia by gas-phase reactions at temperatures of about 400 DEG C. using aluminum silicate-based catalysts in fixed or fluidized beds. Pyridine always has greater significance as well as 3
- For the production of picoline gas phase reactions are used today, by adding formaldehyde to acetaldehyde, in favor of the production of 2- and 4-picolines. - Suppresses the production of picoline. This reaction also
It is carried out in a fixed bed or in a fluidized bed using aluminum silicate as a catalyst at a temperature of about 400°C. According to this process, the yield of 3-picoline, even when obtained in large quantities, reaches only 40 to 44%. At that time, a large amount of pyridine is produced as a by-product. It is also known that the reaction of unsaturated aldehydes, such as acrolein or crotonaldehyde, in place of saturated aldehydes can take place. These reactions take place in the gas phase at high temperatures and the yields are essentially as high as when using saturated aldehydes as starting materials. An object of the present invention is to provide a process for producing 3-picoline in a high yield and suppressing the production of pyridine as much as possible during the production. This objective is achieved according to the invention as follows. That is, starting material 1 consisting of acetaldehyde and/or acetaldehyde acetal and/or crotonaldehyde is mixed with starting material 2 consisting of formaldehyde and/or formaldehyde acetal and/or hexamethylenetetramine in a fluid aqueous phase. At a temperature of 180 to 280℃,
The reaction is carried out in a closed container in the presence of ammonia and/or ammonium ions and in the presence of an anion of an inorganic and/or organic salt whose dissociation constant at 20°C is 10 ⁶ to 10 ^-12 . let In the present invention, the term "acetaldehyde" refers to
The term "formaldehyde" also refers to polymers such as paraldehyde, and the term "formaldehyde" also refers to polymers such as trioxane. Preferably, the individual components of starting materials 1 and 2 are each involved alone in the reaction.
For example, starting material 1 is acetaldehyde or acetaldehyde acetal or crotonaldehyde, and starting material 2 is formaldehyde or formaldehyde acetal or hexamethylenetetramine. Inorganic and/or salts whose dissociation constant at 20°C is between 10 ⁶ and 10 ^-12 are important for the reaction.
In order to incorporate the anion of the organic salt into the reaction solution, the water-soluble alkali and/or ammonium salt of the corresponding acid may be added to the reaction solution. Examples of salts of the above-mentioned acids for use in the present invention are the sodium, potassium or ammonium salts of the following acids. Salts of pentaboric acids such as ammonium pentaborate, salts of carbonates such as ammonium carbonate, salts of phosphoric acids such as potassium dihydrogen phosphate, ammonium dihydrogen phosphate, dipotassium hydrogen phosphate or diammonium hydrogen phosphate, salts of sulfuric acids such as hydrogen sulfate. Sodium or ammonium sulphate, salts of fluoric acids such as sodium fluoride, ammonium fluoride or ammonium hydrogen difluoride, salts of hydrochloric acid such as ammonium chloride, salts of hydrobromic acid such as ammonium bromide, salts of heptamolybdic acid such as ammonium heptamolybdate. , salts of formic acid such as ammonium formate, salts of acetic acid such as sodium acetate or ammonium acetate, salts of propionic acid such as ammonium propionate, salts of lactate such as ammonium lactate, salts of tartaric acid such as disodium tartrate or disodium tartrate, adipic acid. salts of eg diammonium adipate, salts of benzoic acid eg sodium or ammonium benzoate, salts of phthalic acid eg diammonium phthalate, salts of terephthalic acid eg diammonium terephthalate, salts of nicotinic acid eg ammonium nicotinate, and salts of isonicotinic acid such as ammonium isonicotinate, acetaldehyde and/or acetaldehyde acetal and/or crotonaldehyde, formaldehyde and/or
Formaldehyde acetal and/or
The presence of ammonia and/or ammonium ions is essential for the production of 3-picoline from hexamethylenetetramine. If ammonia is used, it can be reacted in gaseous form or also in the form of an aqueous solution, which is sufficient if the alkali salts of the acids mentioned above are initially introduced. However, it is also possible to charge a mixture of alkali salts and ammonium salts.
If ammonia is not used, ammonium salts or mixtures of ammonium salts and alkali salts are used. If mutually immiscible liquid starting materials, such as paraldehyde, are used together with aqueous formaldehyde, a small amount of a homogenizing agent such as an alcohol or a cyclic ether is preferably added to the preformed 3-picoline. It is a good idea to aim for homogenization. Alternatively, immiscible liquid starting materials may be fed into the reactor with separate pumps. According to the invention, surprisingly, 3-picoline is obtained in yields of up to about 65%, while the formation of pyridine is almost completely suppressed (less than 1%).
In the case of 3-ethylpyridine, small amounts of 2,5-dimethylpyridine, 3,5-dimethylpyridine and 2-methyl-5-ethylpyridine are produced as by-products. The process of the invention is preferably carried out in a molar ratio of acetaldehyde and/or acetaldehyde acetal to formaldehyde and/or formaldehyde from 1:0.5 to 1.2, in particular from 1:0.8 to 1:1. If crotonaldehyde is used instead of acetaldehyde and/or acetaldehyde acetal, a suitable molar ratio of crotonaldehyde to formaldehyde and/or formaldehyde acetal is accordingly 1:1.
or move to a range of 1 to 2.4. If hexamethylenetetramine is used in place of formaldehyde and/or formaldehyde acetal, a suitable molar ratio of acetaldehyde and/or acetaldehyde acetal to hexamethylenetetramine is 1:0.083 to 1:0.2. move to the range of The reaction temperature is advantageously 180 to 280°C, particularly preferably 205 to 240°C, most preferably 225 to 235°C. Reaction takes place in fluid phase (aqueous phase)
The reaction is carried out in a closed vessel under the pressure generated by the given reaction temperature. During the reaction,
It is beneficial to stir the reaction system. The amount of ammonia and/or ammonium ions is between 0.5 and 3 mol of ammonia and/or ammonium ions per mole of starting material, preferably between 0.5 and 3 mol of ammonia and/or ammonium ions per mole of starting material.
The range is 2.0 mol. The amount of inorganic and/or organic acid anions ranges from 0.1 to 3 mol, preferably from 0.2 to 1.0 mol, per mole of starting material. The starting PH value of the aqueous reaction solution is preferably between 5.0 and 12.5. Preferably, the aldehyde is added in proportion to its consumption. Therefore, for example, the volume 2
For an operation in which 350 ml of aldehyde is charged into a container, continuous addition over a period of 30 to 90 minutes is suitable. When conducting under other conditions, the addition time may be selected accordingly. Once the desired reaction time has elapsed, the temperature is lowered to approximately room temperature and 3-picoline is obtained from the reaction mixture by known methods. One method is as follows. That is, the PH value of the aqueous phase is first brought to the alkaline range, and then the organic substances are removed from the aqueous reaction mixture using an organic solvent such as benzene,
Toluol, xylol, methylene chloride,
Extract with chloroform, ether, or similar substances. Remove the organic solvent by evaporation and
- Picoline is obtained by fractional distillation. Any other method for separating and obtaining the product can be used within the scope of the invention. One advantage of the novel process according to the invention is that the aqueous phase obtained after extraction of the reaction mixture with an organic solvent can be supplemented with ammonia and/or ammonium ions and used back into the reactor. . The aqueous salt phase consists of the amount of water originally present in the salt solution, the amount of unreacted ammonia and/or ammonium salt, the metal salt originally present depending on the conditions, and the release of the ammonium salt involved in the reaction. and 1 mole of water for each mole of starting material consumed by the reaction. The aqueous salt phase is concentrated by any known method such as evaporation to remove the water formed as a result of the condensation reaction. Replenishment of ammonia and/or ammonium salts is carried out by introducing gaseous ammonia into the aqueous solution at ambient temperature. In doing so, reformation of the ammonium salt with the acid present under the conditions takes place. Although the invention has been described as a discontinuous process, it is of course possible to carry it out as a continuous process within the scope of the invention. In one embodiment of a continuous method, the components involved in the reaction are continuously introduced into a suitable pressure reaction vessel and the reaction mixture is continuously removed therefrom. The reaction products are then separated, the aqueous salt phase is concentrated and the unreacted reactants are recycled into the reaction vessel, replacing the consumed amount. It is also possible to carry out a continuous process or in a reactor in which intimate mixing of the components involved in the reaction takes place under vigorous stirring, for example in a continuously stirred tank-type reactor. Example 1 1140 ml of an aqueous solution (PH8.35) of 3.40 mol of diammonium hydrogen phosphate was heated to 230°C in a volume 2 autoclave and stirred at 1500 rpm. In this solution, 117.7 g of acetaldehyde, hexamethylenetetramine,
A mixture of 49.8 g and 200 g of water was pumped in. (The calculated molar ratio is acetaldehyde:formaldehyde=1:0.78) The reaction pressure thereby varied between 33 and 39 atmospheres. After the addition of the adduct mixture is complete, the reaction mixture is
Stirred for an additional 10 minutes at 230°C, then cooled to room temperature. Finally, it was extracted three times with 100 ml each of methylene chloride and the combined methylene chloride extracts were subjected to gas chromatographic analysis. Upon consumption of the aldehyde, the following products were obtained in the indicated yields based on either the acetaldehyde charge (A) or the charge hexamethylenetetramine (F). Pyridine 1.0% (A), 3-picoline 59.4% (F), 3
-Ethylpyridine 22.8% (A), 2,5-lutidine
4.0% (A), 3,5-lutidine 0.7% (F), 2-methyl-5-ethylpyridine 1.8% (A). The aqueous phase after extraction had a pH of 9.2. All gas chromatographic analyzes were performed using internal standards and taking into account area correction factors. Example 2 1140 ml of a 3.40 molar aqueous solution of diammonium hydrogen phosphate (PH 8.35) was heated to 230° C. in a volume 2 autoclave and stirred at 1500 rpm. In this solution, 117.7 g of paraaldehyde, 49.8 g of hexamethylenetetramine were added continuously over a period of 60 minutes.
A mixture of 130 g of water, 120 g of ethanol was pumped into the tank. (The calculated molar ratio was acetaldehyde:formaldehyde=1:0.80) The reaction pressure thereby varied between 35 and 44 atm.
After the addition of the adduct mixture is complete, the reaction mixture is
Stirred for an additional 10 minutes at 230°C, then cooled to room temperature. Finally, it was extracted three times with 100 ml each of methylene chloride and the combined methylene chloride extracts were subjected to gas chromatographic analysis. As the aldehyde is consumed, the next product is the charged paraldehyde (A) or the charged hexamethylenetetramine.
It was obtained in the yield shown based on either (F). Pyridine 0.8% (A), 3-picoline 65.6% (F), 3-ethylpyridine 19.0% (A), 2,5-lutidine 3.4%
(A), 3,5-lutidine 0.8% (F), 2-methyl-5
- Ethylpyridine 2.8% (A). The aqueous phase after extraction had a pH of 9.4. Example 3 1140 ml of a 3.40 molar aqueous solution of diammonium hydrogen phosphate (PH 8.35) was heated to 220° C. in a volume 2 autoclave and stirred at 1500 rm. paraldehyde in this solution over a period of 59 minutes.
120.0g, hexamethylenetetramine 49.8g, water
A mixture consisting of 120 g and 120 g of ethanol was pumped in. (The calculated molar ratio is acetaldehyde:formaldehyde=1:0.79) The reaction pressure thereby varied between 26 and 44 atm.
After the addition of the starting mixture is complete, the reaction mixture is heated to 220 ml.
Stirred for an additional 10 minutes at 0C, then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each and gas chromatographic analysis of the combined methylene chloride extracts were performed. Upon consumption of the aldehyde, the following products were obtained in the indicated yields based on the charged paraldehyde (A) or the charged hexamethylenetetramine (F). Pyridine 0.3% (A), 3-picoline 51.4% (F), 3-ethylpyridine 6.0% (A), 2,5-lutidine 1.4% (A),
The aqueous phase after extraction had a pH of 9.3 with 2.7% (F) of 3,5-lutidine and 6.8% (A) of 2-methyl-5-ethylpyridine. Example 4 1140 ml of a 3.40 molar aqueous solution of diammonium hydrogen phosphate (PH 8.35) was heated to 230° C. in a volume 2 autoclave and stirred at 1500 rpm. A mixture of 117.7 g of acetaldehyde and 162.2 g of formaldehyde dimethyl acetal was pumped into this solution continuously over a period of 47 minutes. (Molar ratio=1:0.74) Thereby, the reaction pressure varied between 33 and 40 atm. After the addition of the starting mixture was complete, the reaction mixture was stirred at 230° C. for a further 10 minutes and then cooled to room temperature. Finally, two extractions with 100 ml of methylene chloride each and gas chromatographic analysis of the combined methylene chloride extracts were performed. Upon consumption of the aldehyde, the following products were obtained in the indicated yields based on the paraaldehyde (A) or formaldehyde dimethyl acetal (F) charged. Pyridine 0.9% (A), 3-picoline 51.2% (F), 3
-Ethylpyridine 24.6% (A), 2,5-lutidine
4.6% (A), 3,5-lutidine 0.8% (F), 2-methyl-5-ethylpyridine 3.9% (A) Example 5 1140 ml of a 3.40 mol aqueous solution of diammonium hydrogen phosphate (PH 8.35) , heated to 230°C in a volume 2 autoclave and stirred at 1500 rpm. A mixture of 117.7 g of paraldehyde and 162.2 g of formaldehyde dimethyl acetal was pumped into this solution continuously over a period of 64 minutes.
(The calculated molar ratio was acetaldehyde:formaldehyde=1:0.74) The reaction pressure thereby varied between 33 and 40 atmospheres. After the addition of the starting mixture was complete, the reaction mixture was stirred at 230° C. for an additional 10 minutes and then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each and gas chromatographic analysis of the combined methylene chloride extracts were performed. Upon consumption of the aldehyde, the following products were obtained in the indicated yields based on the initial paraldehyde (A) or the initial formaldehyde dimethyl acetal (F). Pyridine 1.0% (A), 3-picoline 53.6% (F), 3
-Ethylpyridine 23.9% (A), 2,5-lutidine
4.3% (A), 3,5-lutidine 0.6% (F), 2-methyl-5-ethylpyridine 2.5% (A) Example 6 855 ml of a 3.40 molar aqueous solution of diammonium hydrogen phosphate (PH 8.35) 230 in an autoclave of 2
℃ and stirred at 1500 rpm. In this solution, 160.0 g of acetaldehyde dimethyl acetal, 160.0 g of a 30% formaldehyde aqueous solution and 22.5 g of 3-picoline were continuously added over a period of 60 minutes.
g of the mixture was pumped in. (The molar ratio is acetaldehyde dimethyl acetal: formaldehyde = 1:0.94) Therefore, the reaction pressure is 33
It varied between ~39 atm. After the addition of the starting mixture was complete, the reaction mixture was stirred at 230° C. for a further 10 minutes and then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each and gas chromatographic analysis of the combined methylene chloride extracts were performed. Upon consumption of the aldehyde, the following products were obtained in the indicated yields based on the initial acetaldehyde dimethyl acetal (A) or the initial formaldehyde (F). Pyridine 1.1% (A), 3-picoline 54.9% (F) (no involvement in homogenization), 3-ethylpyridine 12.7%
(A), 2,5-lutidine 2.6% (A), 3,5-lutidine 1.2% (F), 2-methyl-5-ethylpyridine 0.6
%(A) Example 7 1140 ml of a 3.40 molar aqueous solution of diammonium hydrogen phosphate (PH 8.35) was added to
℃ and stirred at 1500 rpm. 160.0 g of acetaldehyde diethyl acetal, 106.6 g of a 30% formaldehyde aqueous solution, 50.0 g of 3-picoline and 50 g of ethanol were continuously pumped into this solution over a period of 59 minutes. (The molar ratio was acetaldehyde diethyl acetal:formaldehyde=1:0.80) The reaction pressure thereby varied between 33 and 42 atmospheres. After the addition of the educt mixture was complete, the reaction mixture was heated at 230 °C for an additional 10
Stirred for a minute, then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each time and gas chromatographic analysis of the combined methylene chloride extracts were performed. Upon consumption of the aldehyde, the following products were obtained in the indicated yields based on the acetaldehyde diethyl acetal (A) or the formaldehyde (F) charged. Pyridine 0.9% (A), 3-picoline 38.3% (F) (no involvement in homogenization), 3-ethylpyridine 24.6%
(A), 2,5-lutidine 4.6% (A), 3,5-lutidine 1.4% (F), 2-methyl-5-ethylpyridine 3.1
%(A) Example 8 Sodium hydrogen sulfate 157.4g and ammonia
1140 ml of aqueous solution containing 85.1 g (pH of solution =
10.8) was heated to 230°C in autoclave 2 and stirred at 1500 rpm. Continuously add 117.7 ml of acetaldehyde into this solution over a period of 65 minutes.
g and formaldehyde dimethyl acetal
171.0 g of the mixture was injected with a pump. (The calculated molar ratio is acetaldehyde: formaldehyde = 1:0.80) Therefore, the reaction pressure is 43 to 45
Varying between atmospheric pressures. After the addition of the educt mixture was complete, the reaction mixture was stirred at 230 °C for an additional 10 min.
It was then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each time and gas chromatographic analysis of the combined methylene chloride extracts were performed. As the aldehyde was consumed, a yield was obtained based on the charged acetaldehyde (A) or the charged formaldehyde dimethyl acetal (F). Pyridine 2.1%, 3-picoline 53.4% (F), 3
-Ethylpyridine 17.7% (A), 2,5-lutidine
6.8% (A), 3,5-lutidine 1.0% (F), 2-methyl-5-ethylpyridine 3.5% (A) Example 9 1140 ml of an aqueous solution containing 155.1 g of potassium dihydrogen phosphate and 85.1 g of ammonia ( PH of solution=
10.95) was heated to 230°C in a second autoclave and stirred at 1500 rpm. Continuously add 117.7 ml of acetaldehyde into this solution over a period of 65 minutes.
g and formaldehyde dimethyl acetal
171.0 g of the mixture was injected with a pump. (The calculated molar ratio is acetaldehyde:formaldehyde=1:0.80) The pressure of the reaction mixture thereby varied between 47 and 52 atmospheres. After the addition of the starting mixture is complete, the reaction mixture is
Stirred for an additional 10 minutes at 230°C, then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each time and gas chromatographic analysis of the combined methylene chloride extracts were carried out. Upon consumption of the aldehyde, the following products were obtained in the indicated yields based on the aldehyde (A) or formaldehyde dimethyl acetal (F) charged. Pyridine 1.3% (A), 3-picoline 19.3% (F), 3
-Ethylpyridine 32.9% (A), 2,5-lutidine
9.3% (A), 3,5-lutidine 0.4% (F), 2-methyl-5-ethylpyridine 20.8% (A) Example 10 3.40 molar aqueous solution of ammonium acetate (PH
7.55) 230℃ in 1140ml autoclave 2
and stirred at 1500 rpm. In this solution,
Paraaldehyde 96.0 continuously for 51 minutes
g, hexamethylenetetramine 39.8g, water 104g
A mixture consisting of 100 g of ethanol and 100 g of ethanol was injected with a pump. (The calculated molar ratio was acetaldehyde:formaldehyde=1:0.80) The reaction pressure thereby varied between 25 and 32 atmospheres. After the addition of the starting mixture was complete, the reaction mixture was stirred at 230° C. for a further 10 minutes and then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each time and gas chromatographic analysis of the combined methylene chloride extracts were carried out. As the aldehyde was consumed, the following product was obtained in the yield shown based on the paraaldehyde (A) or hexamethylenetetramine (F) charged. Pyridine 1.0% (A), 3-picoline 56.3% (F), 3
-Ethylpyridine 18.5% (A), 2,5-lutidine
5.1% (A), 3,5-lutidine 0.6% (F), 2-methyl-5-ethylpyridine 2.7% (A) Example 11 1140 ml of a 3.40 mol aqueous solution of diammonium hydrogen phosphate (PH 8.35) 220 in an autoclave of 2
℃ and stirred at 1500 rpm. A mixture of 200.0 g of acetaldehyde diethyl acetal and 105.5 g of formaldehyde dimethyl acetal was pumped into this solution continuously over a period of 55 minutes. (The calculated molar ratio is acetaldehyde: formaldehyde =
1:0.80) whereby the reaction pressure varied between 37 and 38 atm. After the addition of the aldehyde mixture was complete, the reaction mixture was stirred at 220° C. for a further 10 minutes and then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each time and gas chromatographic analysis of the combined methylene chloride extracts were carried out. Upon consumption of the aldehyde, the following products were obtained in yields based on the starting acetaldehyde diethyl acetal (A) or the starting formaldehyde dimethyl acetal (F). Pyridine 1.0% (A), 3-picoline 35.7% (F), 3
-Ethylpyridine 34.4% (A), 2,5-lutidine
7.4% (A), 3,5-lutidine 0.3% (F), 2-methyl-5-ethylpyridine 10.6% (A) Example 12 1140 ml of a 3.40 mol aqueous solution of diammonium hydrogen phosphate (PH 8.4) 230 in an autoclave of 2
℃ and stirred at 1500 rpm. 237.0 g of acetaldehyde diethyl acetal was continuously fed into this solution using the first pump, and a mixture consisting of 38.8 g of hexamethylenetetramine and 103 g of water was continuously fed using the second pump over a period of 60 minutes.
(The calculated molar ratio was acetaldehyde:formaldehyde=1:0.85) The reaction pressure thereby varied from 32 to 42 atmospheres. After the addition of the aldehyde mixture was complete, the reaction mixture was further stirred at 230° C. for 10 minutes and then cooled to room temperature. Finally, three extractions with 100 ml of methylene chloride each time and gas chromatographic analysis of the combined methylene chloride extracts were carried out. As the aldehyde was consumed, a yield was obtained based on the charged acetaldehyde diethyl acetal (A) or the charged hexamethylenetetramine (F). Pyridine 0.9% (A), 3-picoline 57.7% (F), 3
-Ethylpyridine 15.6% (A), 2,5-lutidine
2.9% (A), 3,5-lutidine 1.3% (F), 2-methyl-5-ethylpyridine 1.2% (A) Example 13 Aqueous solution containing 397.1 g of dipotassium hydrogen phosphate and 42.6 g of ammonia (solution PH=11.8)
1140 ml was heated to 230°C in a second autoclave and stirred at 1500 rpm. 117.2 g of acetaldehyde was continuously added to this solution over a period of 63 minutes.
and 30.2% aqueous solution of formaldehyde 213.3
g was injected with a pump. (Molar ratio = 1:0.81) Thereby, the reaction pressure varied between 35 and 33 atm. After the addition of the aldehyde mixture was complete, the reaction mixture was further stirred at 230° C. for 10 minutes and then cooled to room temperature. Finally, the organic phase formed is separated and the aqueous phase is
The extracts were extracted twice with 100 ml of methylene chloride and combined with the above organic phase, and the separated aqueous phase was further shaken with 60 ml of methylene chloride. As a result of gas chromatographic analysis of the combined five organic matter layers, the following products were found to be produced as the aldehyde was consumed, with the yield shown based on the charged acetaldehyde (A) or the charged formaldehyde (F). obtained at a rate. Pyridine 1.7% (A), 3-picoline 46.4% (F), 3
-Ethylpyridine 10.4% (A), 2,5-lutidine
4.2% (A), 3,5-lutidine 2.9% (F), 2-methyl-5-ethylpyridine 1.0% (A) All gas chromatographic analyzes used internal standards and took into account the area correction factor. carried out. Examples 14-17 Examples 14 to 17 were carried out in principle in the same manner as Example 13. The results are shown below. 【table】

Claims (1)

[Scope of Claims] 1 Educt 1 consisting of acetaldehyde and/or acetaldehyde acetal and/or crotonaldehyde together with educt 2 consisting of formaldehyde and/or formaldehyde acetal and (or) hexamethylenetetramine, in a fluid aqueous phase at a temperature of 180 to 280 °C in a closed container in the presence of ammonia and/or ammonium ions, the dissociation constant of the salt at 20 °C is from ¹⁰ to 10 ^-12 A method for producing 3-picoline, which comprises reacting in the presence of an anion of an inorganic and/or organic salt. 2. Acetaldehyde as it is or in the form of its derivative, and formaldehyde as it is or in the form of its derivative, in a molar ratio ranging from 1:0.5 to 1:1.2. Method of Section 1. 3 The anion of the inorganic and/or organic salt is combined with the corresponding water-soluble alkali and/or
Claim 1 or 2, characterized in that the ammonium salt is introduced into the reaction solution in the form of an ammonium salt.
Section method. 4. The method according to any one of claims 1 to 3, characterized in that the reaction is carried out at a temperature of 205 to 240°C. 5. The method according to any one of claims 1 to 3, characterized in that the salt concentration in the aqueous solution is used at a concentration of 0.3 to 10 mol/.