JPH09124602A - Production of 3,5-lutidine and 2,3,5-collidine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the above compound useful as an intermediate for agrochemicals, etc., in a high yield from inexpensive raw material. SOLUTION: Methacrolein is reacted with methylethyl ketone in an amount of <=10 times by mol equivalent based on methacrolein and ammonia or methylamine in the presence of an acid catalyst (e.g. sulfuric acid) having pKa value of <=6 and/or an ammonium salt (e.g. ammonium slat) at 150-350 deg.C in a liquid phase under high pressure to provide the objective 3,5-lutidine or 2,3,5- collidine. As an amount of each reagent used in reaction, methylethyl ketone is preferably used in an amount of 0.1-2 times by mole equivalent based on methacrolein and an acid catalyst is preferably used in an amount of 0.01-0.5mol equivalent based on the raw material and the ammonium salt is preferably used in an amount of 0.05-0.1mol equivalent based on the raw material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to pyridine compounds 3,5-lutidine and 2,3,5-collidine which are useful as intermediates for agricultural chemicals and the like.

[0002]

2. Prior Art and Problems to be Solved by the Invention
-Regarding the method for producing lutidine, methacrolein and acetaldehyde are used as raw materials, and a catalyst in which lead fluoride is supported on silica / alumina is used to react in a gas phase system (Japanese Patent Publication No. 40-6345). ,
A method of reacting with gaseous ammonia in the presence of ammonium chloride under high pressure in a liquid phase system (JP-A-47-6871) is known. On the other hand, as to the method for producing 2,3,5-collidine, a method for obtaining the compound in a single step from an aldehyde or a ketone such as methacrolein is not known.

The manufacturing method disclosed in Japanese Examined Patent Publication No. 40-6345 discloses a method in which, in addition to the objective 3,5-lutidine, 3
-Methylpyridine is produced in a large amount, and it cannot be said that 3,5-lutidine is efficiently produced. In addition, JP-A-47-687
Regarding the production of 3,5-alkylpyridines disclosed in Japanese Patent Publication No. 1, the yield is as low as 40% or less, and the use of gaseous ammonia restricts the materials used in the reactor. A fairly high pressure is required for the reaction.

An object of the present invention is to produce 3,5-lutidine and 2,3,5-collidine from methacrolein and methyl ethyl ketone in good yield.

[0005]

The present invention provides methacrolein and up to 10 molar equivalents of methyl ethyl ketone with ammonia or methylamine with respect to methacrolein.
3,5-lutidine and 2,3,5 characterized by the presence of an acid catalyst and / or an ammonium salt having a pKa value of 6 or less in the reaction in a liquid phase under high pressure at a temperature of 150 to 350 ° C. -A method for producing collidine.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The use ratio of methacrolein and methyl ethyl ketone, which are the reaction raw materials of the present invention, is such that methyl ethyl ketone is used in an amount up to 10 times, preferably 0.1 to 2 times the molar equivalent of methacrolein. . As a matter of course, 3,5 produced depending on the use ratio of the reaction raw materials
-The yields and production ratios of lutidine and 2,3,5-collidine are different.

The reaction is carried out at a temperature of 150 to 350 ° C.
It is preferable to carry out at a high pressure in the range of 10 to 100 atm when ammonia is used, and at 10 to 60 atm when methylamine is used. As the ammonia used in the reaction, 30% or less aqueous ammonia may be used as it is. The reaction time is 1-15 hours, preferably 2 depending on other reaction conditions.
-Varies in 8 hours.

In the present invention, a pK of 6 or less is used during the reaction.
An acid catalyst having an a value and / or an ammonium salt is present. As the acid catalyst having a pKa value of 6 or less, for example, sulfuric acid, hydrochloric acid, formic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and the like are preferable, and the addition amount is 0.01 to 0.5 with respect to the raw material. Molar equivalents are preferred. The type of ammonium salt to be added is preferably ammonium chloride, ammonium acetate, ammonium sulfate, hydroxylamine hydrochloride, or the like.
The addition amount is appropriately 0.01 to 0.5 molar equivalent, preferably 0.05 to 0.1 molar equivalent, based on the raw material. These acid catalysts or ammonium salts may be used alone or in combination. A polar solvent such as water, methanol or ethanol is required as a solvent during the reaction, and water is particularly preferable.

As a method for separating the products after the reaction, first, the ammonia remaining in the reaction solution is distilled off under reduced pressure, and 0.5 to 10 times the weight of the reaction solution, such as hexane and dichloromethane, is added. The compound is extracted with a solvent such as chloroform. Preferably this extraction is 2-10
Repeated times, water in the solvent is removed by a dehydrating agent such as magnesium sulfate which is equivalent to 0.0001-0.01 times the weight of the extraction solvent, and the dehydrating agent is removed by filtration. The solvent of the filtrate is preferably reduced to 100 torr or less under reduced pressure. 30-60
The solvent is distilled off by heating to a temperature range of ° C, and then 3,5-lutidine and 2,3,5-collidine are distilled off by distillation.

[0010]

The present invention will be described in more detail with reference to the following examples. Example 1 61 g of 40% methylamine aqueous solution was added to SUS.
After charging into an autoclave manufactured by the above, 14.0 g (0.20 mol) of methacrolein and 7.2 g (0.10 mol) of methyl ethyl ketone were added and mixed while cooling.
Further, after adding 19.8 g of 36% hydrochloric acid aqueous solution, the mixture was heated to 250 ° C., kept at that temperature at 30 kg / cm ^{2 for} 3 hours, and then cooled to 30 ° C. in a water bath.

Unreacted methylamine was distilled off from the reaction solution at room temperature under reduced pressure (200 torr). After degassing, the reaction solution was transferred to a separating funnel and extracted with 103.4 g of hexane. After separating the hexane layer and the aqueous layer, the aqueous layer was subsequently extracted with 96.4 g of dichloromethane. When the hexane layer and the dichloromethane layer were analyzed by gas chromatography, respectively, it was found that the extracted 3,5-lutidine and 2,3,5-collidine were contained in total of 2.47 g and 0.92 g, respectively. It was The yields were 23.0% and 7.9% based on methacrolein and methyl ethyl ketone, respectively.

[Example 2] 14.0 g of methacrolein
(0.20 mol), methyl ethyl ketone 14.2 g
(0.20 mol), 5.0 g of ammonium chloride (0.
(093 mol) and 60.2 g of water were charged into an SUS autoclave, and after sealing, 10.0 g of ammonia was added and mixed while cooling in a dry ice / acetone bath. After the addition was completed, the temperature was raised to 250 ° C and the temperature was raised to 68k.
After holding at g / cm ^{2 for} 8 hours, it was cooled to 30 ° C. in a water bath.

Unreacted ammonia was distilled off from the reaction solution at room temperature under reduced pressure (200 torr). After degassing, the reaction solution was transferred to a separating funnel and extracted with 100.7 g of hexane. After separating the hexane layer and the aqueous layer, the aqueous layer was subsequently extracted with 110.0 g of dichloromethane. When the hexane layer and the dichloromethane layer were analyzed by gas chromatography, respectively, it was found that the extracted 3,5-lutidine and 2,3,5-collidine were contained in total of 0.69 g and 1.68 g, respectively. It was The yields for methacrolein and methyl ethyl ketone were 6.4% and 6.9%, respectively.

[Example 3] 40% aqueous solution of methylamine 6
After charging 0.0 g into a SUS autoclave, 14.0 g (0.20 mol) of methacrolein while cooling.
Was mixed. Furthermore, after adding 9.8 g of 36% hydrochloric acid aqueous solution, the temperature is raised to 250 ° C. by heating to 35 kg.
/ Cm ² After holding for 3 hours, it was cooled to 30 ° C. in a water bath.

Unreacted methylamine was distilled off at room temperature under reduced pressure (200 torr). After degassing, the reaction solution was transferred to a separating funnel and extracted with 94.0 g of hexane. After separating the hexane layer and the aqueous layer, the aqueous layer was subsequently extracted with 96.7 g of dichloromethane. When the hexane layer and the dichloromethane layer were analyzed by gas chromatography, respectively, it was found that the total amount of the extracted 3,5-lutidine was 5.32 g. The yield based on methacrolein was 49.7%.

Comparative Example 1 The reaction and operation were carried out under the same conditions as in Example 3 except that the 36% aqueous hydrochloric acid solution was not added. When analyzed by gas chromatography, the yield of 3,5-lutidine based on methacrolein was 13.6%.

[Comparative Example 2] In Example 3, boric acid (pKa = 6.1) was used instead of 9.8 g of 36% hydrochloric acid aqueous solution.
The reaction and operation were carried out under the same conditions as in Example 3 except that was added. When analyzed by gas chromatography, the yield of 3,5-lutidine based on methacrolein was 15.9%.

Comparative Example 3 The reaction and operation were carried out under the same conditions as in Example 3 except that 3.6 g of ferric chloride was added instead of 9.8 g of 36% hydrochloric acid aqueous solution. When analyzed by gas chromatography, the yield of 3,5-lutidine based on methacrolein was 10.8%.

[Example 4] 29.3 g of methacrolein
(0.42 mol), p-toluenesulfonic acid 9.1 g
(0.048 mol) and 60 g of water made of SUS
After charging into the clave, and after sealing, dry ice / aceto
Add 10.0 g of ammonia while cooling in a bath
did. After the addition was completed, the temperature was raised to 250 ° C and the temperature was raised to 6
7kg / cm ^Two After 3 hours of holding in a water bath
Cooled to ° C.

Unreacted ammonia was distilled off from the reaction solution at room temperature under reduced pressure (200 torr). After degassing, the reaction solution was transferred to a separating funnel and extracted with 113.2 g of hexane. After separating the hexane layer and the aqueous layer, the aqueous layer was subsequently extracted with 104.4 g of dichloromethane. When the hexane layer and the dichloromethane layer were analyzed by gas chromatography, respectively, it was found that the extracted 3,5-lutidine was contained in a total amount of 4.83 g. The yield based on methacrolein was 22.5%.

[0021]

According to the present invention, by using ammonia or methylamine in an equivalent amount or more from inexpensive methacrolein and methyl ethyl ketone, the yield is 3,5.
-Lutidine and 2,3,5-collidine can be industrially synthesized.

Claims (1)

[Claims] 1. Methacrolein and 10 times molar equivalents of methyl ethyl ketone to methacrolein are reacted with ammonia or methylamine in the liquid phase under high pressure at a temperature of 150-350 ° C. and a pKa value of 6 or less is obtained. 3,5-lutidine and 2,3,5-characterized by the presence of an acid catalyst and / or ammonium salt having
Collidine production method.