JPS6348266B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention deals with low-quality β containing γ-picoline.
- This relates to a method for producing highly pure β-picoline by subjecting γ-picoline in picoline to a catalytic reaction. β-picoline is important as an intermediate raw material for agricultural medicines, and in recent years there has been a strong demand for β-picoline that does not contain γ-picoline. The conventional method for producing high-purity β-picoline is that the boiling points of γ-picoline and β-picoline are 143.1°C and 143.8°C.
Since they are very close to each other, it is impossible to separate the two by simple operations such as distillation, and methods are used to suppress the by-product of γ-picoline during production. For example, according to Japanese Patent Publication No. 47-44746, acrolein (hereinafter abbreviated as AL) and acetaldehyde (hereinafter abbreviated as AL)
When producing pyridine and β-picoline from AL/
When the molar ratio of AD is 1, the amount of γ-picoline produced is 0.04 for every 1 β-picoline produced by adding methanol to AD in equal moles, which is an improvement compared to when methanol is not added (0.42 in the case of no addition). However, it is still not satisfactory. Also
According to Chemiker-Zeitung 101 (1977) 377-384, when β-picoline and pyridine are produced from AL alone, the by-product of γ-picoline is small and
- It has been reported that γ-picoline is about 0.001 to 1 picoline, but it is not possible to completely suppress γ-picoline. Furthermore, in this case, acrolein, which has high reactivity, is used alone, which makes it difficult to handle, and there are also problems such as a large amount of carbon depositing on the catalyst during the reaction, and a rapid decline in catalyst activity. It's not a particularly good method. Based on the above-mentioned facts, the present inventor has conducted extensive studies on a method for directly producing high-purity β-picoline that does not contain γ-picoline from low-quality β-picoline that contains γ-picoline. It was discovered that there is a difference in reactivity between γ-picoline and β-picoline, and that γ-picoline reacts more easily than β-picoline when brought into contact with an oxygen-containing gas in the presence of a catalyst, which is the main component. , we have completed the present invention. That is, the present invention is a high-density polymerization method characterized in that γ-picoline is selectively removed by catalytically reacting β-picoline containing γ-picoline with an oxygen-containing gas in the gas phase in the presence of a catalyst containing vanadium as a main component. This is a method for producing pure β-picoline. The catalyst used in the present invention may be one containing vanadium as a main component, such as vanadium oxide (V ₂ O ₅ ) alone or the same compound containing chromium, silver,
A catalyst to which molybdenum, tungsten, etc. are added can be used. Vanadium compounds such as ammonium metavanadate, vanadyl chloride, meta- or pyrovanadic acid, vanadium oxalate, and vanadium oxide are used as catalyst constituent raw materials. Other additive metals include chromium nitrates, hydrochloride oxides, chromium compounds such as chromic acid, molybdenum compounds such as molybdic acid, ammonium molybdate, and molybdenum oxide, tungsten compounds such as tungstic acid, ammonium tungstate, and tungsten oxide, silver nitrate, Silver compounds such as silver acetate, silver lactate, and silver oxide are used. Although the catalyst according to the present invention can be used without a carrier or supported on a suitable carrier, it is more effective to use it supported on a carrier. Materials used as carriers include alumina, silica,
Silicon carbide, pumice, titanium oxide, etc. are suitable.
Although the amount of carrier varies depending on the type of carrier used, it is generally desirable to prepare the composition so that the carrier content is 95% or less, particularly 5 to 95% by weight. The catalyst is prepared by a common method used to prepare this type of catalyst. For example, oxalic acid is gradually added to ammonium metavanadate while heating an aqueous suspension to form a homogeneous solution. Add the carrier to this solution and concentrate while mixing well. After drying, the resulting cake is molded into an appropriate size and calcined at a temperature of 300 to 600°C to obtain a catalyst. Further, when various metals are added, preparations can be made according to the method described above. The catalyst according to the present invention can be used in either a fixed bed or a fluidized bed. γ- in β-picoline, the raw material used in the present invention
The picoline content is usually 10% or less, but it is not particularly regulated. The oxygen source may be pure oxygen, air with increased oxygen concentration, or air without added oxygen. For economic reasons, it is preferable to use air as the oxygen-containing gas. It is preferable to add water vapor to the raw material picoline together with an oxygen-containing gas in a reactor. Addition of steam not only increases the production of useful pyridine by dealkylating a portion of γ-picoline and β-picoline, but also has the effect of preventing explosions and ensuring safety. For safety reasons, if necessary, additionally known inert gases such as nitrogen, argon, etc. can be used as diluents. The supply ratio of oxygen to picolines is a molar ratio.
0.1 to 1.0, and when the oxygen molar ratio is large, the conversion rate of β-picoline increases, and the desired high purity β
- The gain rate of Picolin will be reduced. On the other hand, if this ratio is small, the rate of change of γ-picoline will decrease, so it is better to determine the molar ratio appropriately depending on the desired purity. The supply ratio of water to picoline is preferably 35 times or less in terms of molar ratio. A large molar ratio of water is desirable because it improves the recovery rate of converted picoline to useful pyridine, but it is not preferable to make it larger than necessary because the conversion rate of picoline decreases. The contact time of the raw material gas is 0.5 to 20 seconds. In the present invention, the reaction temperature suitable for producing high purity β-picoline is 300 to 500°C. Further, the reaction can be carried out without any particular pressure restrictions. The product liquid obtained by the reaction contains β-picoline and dealkylated pyridine, and highly pure β-picoline can be easily obtained from this by known methods such as distillation, and is further useful. Pyridine can also be recovered at the same time. According to the present invention, it is possible to apply the reaction conditions to low-quality β-picoline containing γ-picoline, particularly the oxygen/picoline supply ratio, and more preferably to the water/picoline supply ratio.
By appropriately selecting the supply ratio of picoline, etc., it is possible to selectively induce a large change rate of γ-picoline and obtain highly pure β-picoline that contains virtually no γ-picoline. Next, the present invention will be described in more detail with reference to Examples. Example 1 100 ml of water is added to 6.4 g of ammonium metavanadate, and while stirring vigorously, 5.4 g of oxalic acid is gradually added to completely dissolve the ammonium metavanadate. Next, add 15.7g of chromium nitrate and 20ml of water.
After completely dissolving, add to the oxalic acid solution of ammonium metavanadate. Further, 1.5 g of silver nitrate was dissolved in 20 ml of water, added to the mixture, and stirred well. Separately, spherical alumina (5 mmφ) used as a carrier is heated on a sand bath, and the catalyst component mixture is sprinkled little by little onto it to impregnate it. After drying the obtained catalyst at 120℃ for 1 hour
It was baked at 450°C in air for 3 hours. The composition ratio of the obtained catalyst is V ₁ Cr0.7Ag0.16O3.63
(15wt%) - Al ₂ O ₃ (85wt%). 60ml of the above catalyst is placed in a stainless steel U with an inner diameter of 27.2mmφ.
Filled in a shaped reaction tube, using β-picoline containing 2.5% γ-picoline, a mixed gas with a molar ratio of picoline:air:water of 1:3.5:15 was contacted for 9 seconds.
The reaction was carried out at a reaction temperature of 320°C. When the reaction crude liquid was analyzed by gas chromatography, there was no γ-picoline at all, and 29.1% of the charged picoline had changed.
Pyridine useful for altered picoline is 74.5
% was generated. Examples 2 to 4 The catalyst and picoline used in Example 1 were used, but only the reaction conditions were changed. The results were as shown in the table below.

[Table] Example 5 A commercially available catalyst containing 10% vanadium oxide (Harshaw V-0601T. Alumina carrier) was used, the same picoline used in Example 1 was used, the reaction temperature was 320°C, and the picoline:air The gases were reacted at a molar ratio of :water=1:2.4:16 for a contact time of 10 seconds. result,
13.4% of the charged picoline has changed, and the ratio of γ-picoline/β-picoline in the crude reaction solution is
It had dropped to 0.002.

[Claims]

1. α-picoline or substituted α-picoline, consisting of contacting aniline or substituted aniline with a crystalline zeolite catalyst and separating α-picoline or substituted α-picoline from the resulting product stream. -The manufacturing method of picoline. 2. The production method according to claim 1, wherein aniline is brought into contact with zeolite in the presence of ammonia. 3 The molar ratio of ammonia:aniline is 0.5:1~
The manufacturing method according to claim 2, wherein the ratio is 25:1. 4. A process according to any one of claims 1 to 3, wherein the zeolite has a silica:alumina ratio of at least 12:1 and a control index of 1 to 12. 5 Zeolite is ZSM-5, ZSM-11, ZSM-
35 or ZSM-38. 6. The production method according to any one of claims 1 to 5, wherein aniline is brought into contact with zeolite at a temperature of 200°C to 650°C, a pressure of 200 to 25000 kPa, and a space velocity of 0.1 to 50 weight hours. 7 A phenolic compound or a phenolic compound having a substituent group is combined with ammonia or an amine with a silica:alumina ratio of at least 12 and a control index of 1 to 12.