JP2009107964A - Method for producing 2-ethyl-2-propenal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently and commercially favorably producing 2-ethyl-2-propenal. <P>SOLUTION: This method for producing 2-ethyl-2-propenal comprises dropwisely adding 0.05 to 0.5 mole of an alkali metal or alkaline earth metal carbonate and/or bicarbonate to a 5 to 35°C mixture of 1.0 mole of n-butyl aldehyde and 0.9 to 1.5 mole of formaldehyde, or dropwisely adding 0.9 to 1.5 mole of formaldehyde and 0.05 to 0.5 mole of an alkali metal or alkaline earth metal carbonate and/or bicarbonate to 1.0 mole of 5 to 35°C n-butyl aldehyde, then heating the mixture to react in a whole refluxing state, and finally distilling the reaction solution, to produce a fraction containing 2-ethyl-2-propenal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for efficiently producing 2-ethyl-2-propenal, which is one of α-alkylacroleins.

2-Ethyl-2-propenal (2-ethylacrolein, hereinafter referred to as ECR) is a compound useful as various chemical raw materials, and is useful as a starting material for the production of pyridine or quinoline derivatives, as well as ditrimethylolpropane. (Hereinafter referred to as di-TMP) and the like. In particular, a method for efficiently synthesizing di-TMP by reacting trimethylolpropane (hereinafter referred to as TMP) and ECR is known (see Patent Document 1). di-TMP is a by-product of industrial production of TMP by aldol condensation and cross-kanitz allo reaction of normal butyraldehyde (hereinafter referred to as NBD) and formaldehyde (hereinafter referred to as HCHO) under a basic catalyst. The yield of di-TMP in this method is generally 5% or less based on the TMP yield (see Patent Document 2). When obtaining di-TMP, the reaction of ECR and TMP can be obtained much more efficiently.
As a method for obtaining α-alkylacrolein, various methods are known in which NBD and HCHO are reacted by Mannich reaction or aldol reaction in the presence of an organic amine as a catalyst or a reaction reagent (see Patent Documents 3 to 6). .
There is also known a method in which ECR is circulated in a method for producing TMP using an alkali metal or alkaline earth metal carbonate and / or bicarbonate without using an organic amine (see Patent Document 7). ).
JP-T 9-268150 Japanese Patent Laid-Open No. 2005-23067 JP 55-87735 A Japanese Patent Laid-Open No. 9-295956 Japanese Patent Laid-Open No. 11-209323 Special table 2001-506658 gazette JP-A-11-49708

  The method of efficiently obtaining ECR as a main product has the following problems. 2-Propenal, for example, if it is unsubstituted 2-propenal (acrolein) or 2-methyl-2-propenal (methacrolein), is produced industrially in large quantities by the gas phase oxidation reaction of propylene and isobutylene, respectively. ing. Similarly, ECR is thought to be obtained by gas phase oxidation of the corresponding 2-methyl-1-butene, but in practice, not only the methyl group directly bonded to the double bond but also the double bond Since the methylene part of the ethyl group at the α-position is also oxidized, ECR cannot be efficiently obtained as the main product. Further, 2-methyl-1-butene itself is not as easy as industrial materials and can be obtained in large quantities as much as propylene and isobutylene.

  As a method of obtaining α-alkylacrolein, a method of reacting NBD and HCHO by Mannich reaction or aldol reaction in the presence of an organic amine as a catalyst or as a reaction reagent is an expensive organic amine as a reaction reagent or a catalyst. When used as, it is necessary to have a step of distillation recovery after the reaction and reuse it, which is industrially complicated and disadvantageous. In addition, when ECR is used as a raw material for the next reaction, when organic amines are not used for the reaction, secondary materials are used, which is industrially disadvantageous. Moreover, since there is an amine-derived nitrogen content, nerves are required for detoxifying the waste liquid treatment after obtaining the ECR. Furthermore, in the case of the aldol reaction carried out so far, the ECR yield is generally about 20% based on the HCHO standard and cannot be industrially implemented as an ECR synthesis method.

  In the production method of TMP using an alkali metal or alkaline earth metal carbonate and / or bicarbonate without using organic amines, the ECR obtained by the method of reusing ECR is small. It cannot be industrially implemented as a method to obtain as a main product. An object of the present invention is to provide a method for producing ECR efficiently and industrially advantageously.

  As a result of intensive studies on the production method of ECR having the above-mentioned problems, the present inventors have found that a mixture of 1.0 mol NBD and 0.9 to 1.5 mol HCHO has a content of 0.01 to 0. .5 moles of alkali metal or alkaline earth metal carbonate and / or bicarbonate added, or 0.9 mole of NCHO at 5 to 35 ° C. with 0.9 to 1.5 moles of HCHO and 0 0.05 to 0.5 moles of alkali metal or alkaline earth metal carbonate and / or hydrogen carbonate was added dropwise, and then heated to complete reflux for reaction, followed by distillation, The inventors have found that ECR can be efficiently produced without using expensive side reagents such as amines, and have completed the present invention.

That is, the present invention relates to a method for producing 2-ethyl-2-propenal described in the following (A) to (F).
(A) Maintaining a mixture of normal butyraldehyde and formaldehyde at 5 to 35 ° C. and adding a base catalyst, or adding formaldehyde and a base catalyst in parallel to normal butyraldehyde held at 5 to 35 ° C. Then, the whole is refluxed by heating to complete the reaction, and then a 2-ethyl-2-propenal-containing fraction is obtained by distillation to obtain a fraction containing 2-ethyl-2-propenal.
(B) The method for producing 2-ethyl-2-propenal according to (A), wherein the base catalyst is an alkali metal or alkaline earth metal carbonate and / or bicarbonate.
(C) The method for producing 2-ethyl-2-propenal according to (A) to (B), wherein the base catalyst is added dropwise as an aqueous solution.
(D) 2-ethyl according to (A) to (C), wherein formaldehyde is 0.9 to 1.5 mol and the base catalyst is 0.05 to 0.5 mol with respect to 1.0 mol of normal butyraldehyde. -2-Propenal production method.
(E) The method for producing 2-ethyl-2-propenal according to (A) to (D), wherein the time for heating to complete the reaction is 0.5 to 3 hours.
(F) The method for producing 2-ethyl-2-propenal according to (A) to (E), wherein water is distilled together with 2-ethyl-2-propenal during distillation.

  According to the present invention, ECR can be efficiently produced from NBD and HCHO. In the method of the present invention, NBD, which is an unreacted raw material having a lower boiling point than the reaction product, can be recovered by distillation and recycled, so that the present invention is an industrially excellent method.

Hereinafter, the present invention will be described in more detail. The reaction formula of the method of the present invention is shown in Formula (1).

  As the NBD used in the present invention, a commercially available product is used as it is, or a product obtained by further purifying the commercially available product by distillation or the like.

  The form of HCHO used in the present invention is not limited as long as it is a normal industrial standard. That is, a formalin aqueous solution of each standard concentration or solid paraformaldehyde can be selected in a form most suitable for the production method. The amount of HCHO used (theoretical molar ratio = 1.0) is 0.9 to 1.5, preferably 0.95 to 1.1 in terms of molar ratio to 1 mol of NBD. When the amount of HCHO used for NBD is smaller than the range, the reaction is slow, and the amount of raw material recovery and by-products is increased, which is not preferable. If the amount of HCHO used is larger than the range, the amount of TMP and other by-products produced increases, which is not preferable.

The base catalyst in the present invention is an alkali metal, alkaline earth metal hydroxide, or carbonate such as sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, Examples thereof include lithium carbonate and sodium hydrogen carbonate. Preferably, alkali metal and / or alkaline earth metal carbonates and / or hydrogen carbonates, particularly preferably those containing alkali metal carbonate as a main component are used. . Sodium salts are common for industrial practice. The base catalyst may be a carbonate or a mixture with bicarbonate generally used as an industrial chemical. Further, it may be a bicarbonate produced by oxidizing or hydrolyzing a formate which is a by-product of TMP production, or a mixture with a carbonate. The addition method of the base catalyst may be added as powder, but it is easy to add as an aqueous solution. The usage-amount of a base catalyst is 0.05-0.5 by the molar ratio with respect to 1.0 mol NBD, Preferably it is 0.08-0.2. When the amount of the base catalyst used is smaller than the range, the reaction is slowed down, and the amount of raw material recovery and by-products is increased. When the amount of the base catalyst used is larger than the range, the amount of TMP and other by-products generated increases.

  The reaction temperature of NBD and HCHO of this invention is 5-35 degreeC, Preferably it is 15-30 degreeC. It is industrially disadvantageous to lower the reaction temperature during the addition duration below 5 ° C, and the reaction rate of NBD and HCHO is not sufficient. On the other hand, when the reaction temperature is higher than 35 ° C., by-products increase, which is not preferable. In this reaction, the order of addition of NBD, which is a reaction reagent, is important, and it is important that NBD is not brought into contact with the base catalyst in the state where HCHO is absent or insufficient. When heating is performed in a contact state between NBD and a base catalyst, NBDs react with each other. Therefore, NBD and a base catalyst must be dropped in the presence of excess HCHO, or HCHO, NBD, and a base catalyst must be contacted at the same time. For example, a method of adding an aqueous HCHO solution and a base catalyst mainly composed of carbonate to NBD in parallel, or a method of adding a base catalyst to a mixed aqueous solution of NBD and HCHO is used. As the reaction solvent, one or a plurality of organic solvents such as aliphatic ethers such as dioxane, tetrahydrofuran, diglyme and tetraglyme can be used as long as they are miscible with the reaction reagent. Water is used for. There is no particular limitation on the amount of solvent used, and only the amount of HCHO aqueous solution and base catalyst solution brought in may be used, or the solvent may be added to dilute, but high dilution is particularly industrial in terms of volumetric efficiency. Disadvantageous.

  When the addition of the base catalyst solution is completed, the reaction temperature is raised and aging is performed at a total reflux (heating until the temperature in the reaction kettle reaches 80 to 90 ° C). In order to maintain a predetermined reaction temperature and to prevent the escape of ECR and the like, the reaction system is maintained at a normal pressure or higher, usually under a pressure of 0.1 to 0.5 MPa. If necessary, pressurization may be performed with an inert gas such as nitrogen or argon. The time required for this aging step is 0.5 to 3 hours, preferably 1 to 2 hours. If the aging time is shorter than this range, the amount of ECR produced is not sufficient. Also, if the aging time is longer than this range, the ECR alteration may occur and the amount of ECR acquisition decreases.

  Since ECR is generated by dehydration reaction from alkanal in which 1 mol of HCHO is added to 1.0 mol of NBD, some alkanals are converted to ECR by dehydration reaction, so distillation recovery is recovery of ECR. This is a more advantageous method. The ECR distillation recovery is carried out while distilling water together with the ECR in order to increase the recovery rate until the top temperature is the boiling point of water at the operating pressure, that is, 100 ° C. if it is normal pressure. The bottom temperature of the distillation column when ECR is recovered by distillation is 80 ° C to 110 ° C, preferably 95 to 105 ° C. In the present invention, the reaction of NBD and HCHO and the distillation recovery of ECR may be performed in separate reactors or sequentially in the same reactor without distinction. In order to separate a small amount of NBD or the like having a boiling point lower than that of ECR, the number of distillation columns used for distillation recovery is increased to increase the separation efficiency.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, of course, this invention is not limited by these Examples.
[Gas chromatography analysis conditions]
Apparatus: HP-5890 (manufactured by Hewlett-Packard Company)
Column used: DB-1 (manufactured by Agilent Technologies)
Analysis conditions: injection temp. 250 ℃,
detection temp. 250 ℃
Column temperature: 60 ° C constant temperature for 6 minutes → Increased from 60 ° C to 250 ° C at 7 ° C / minute → 250 ° C constant temperature for 20 minutes Detector: Hydrogen flame ionization detector (FID)

Example 1
In a 500 mL Pyrex (registered trademark) flask equipped with a reflux condenser, a thermometer, and a stirrer, 122 g of a 40% formaldehyde aqueous solution (equivalent to 1.62 mol as HCHO) and 117 g (1.62 mol) of NBD were mixed and mixed. While maintaining the mixed solution at 0 ° C., a 20 wt% aqueous solution corresponding to 8.5 g (0.08 mol) of sodium carbonate was added dropwise over 10 minutes with a pump. Thereafter, the mixture was heated, the temperature controller was set to 120 ° C., and the mixture was heated with a mantle heater until the temperature of the reaction kettle reached 80 to 90 ° C., and was fully refluxed for 120 minutes. Then, it distilled under normal pressure and obtained the fraction isolate | separated into the organic phase 78g and the water phase 27g as a fraction to distillation tower top temperature 100 degreeC. As a result of GC analysis, 56 g (0.67 mol) of ECR was produced in the organic phase. This corresponds to a yield of 42 mol% based on the raw material NBD.

Example 2
In a 500 mL Pyrex (registered trademark) flask equipped with a reflux condenser, a thermometer, a dropping funnel, and a stirrer, NBD 117 g (1.62 mol) was placed and maintained at 30 ° C. while maintaining a temperature of 30 ° C., 122 g (as HCHO) 1.62 mol) was added dropwise in 20 minutes. 5 minutes after the start of HCHO dropping, a 20 wt% aqueous solution corresponding to 8.5 g (0.08 mol) of sodium carbonate was added dropwise over 20 minutes using a pump. Thereafter, the mixture was heated to reflux the mixture for 120 minutes. Then, it distilled under normal pressure and obtained the fraction isolate | separated into the organic phase 76g and the water phase 23g as a fraction to distillation tower top temperature 100 degreeC. As a result of GC analysis, 58 g (0.69 mol) of ECR was produced in the organic phase. This corresponds to a yield of 42 mol% based on the raw material NBD.

Comparative Example 1 (added NBD and sodium carbonate to HCHO)
A 500 mL Pyrex (registered trademark) flask equipped with a reflux condenser, a thermometer, a dropping funnel, and a stirrer was charged with 122 g of a 40% formaldehyde aqueous solution (equivalent to 1.62 mol as HCHO) and maintained at 30 ° C. while maintaining 117 g of NBD. (1.62 mol) was added dropwise over 20 minutes. At the same time, a 20 wt% aqueous solution corresponding to 8.5 g (0.08 mol) of sodium carbonate was added dropwise by a pump over 2 minutes. Thereafter, the mixture was heated and fully refluxed for 120 minutes, and then distilled under normal pressure to obtain a fraction that was separated into 66 g of an organic phase and 23 g of an aqueous phase as a fraction having a distillation column top temperature of 100 ° C. As a result of GC analysis, 39 g (0.46 mol) of ECR was produced in the organic phase. This corresponds to a yield of 28 mol% based on the raw material NBD.

Comparative Example 2 (Adding HCHO, NBD, and sodium carbonate to water)
A 500 mL Pyrex (registered trademark) flask equipped with a reflux condenser, a thermometer, two dropping funnels, and a stirrer was charged with 31 g of water and maintained at 30 ° C. while maintaining 122 ° C. of 40% formaldehyde aqueous solution (1.62 as HCHO). 20 wt% aqueous solution corresponding to 117 g (1.62 mol) of NBD, 8.5 g (0.08 mol) of sodium carbonate, and 20 minutes in parallel with a pump. Thereafter, the mixture was heated and refluxed for 120 minutes, followed by distillation under normal pressure to obtain a fraction that was separated into 109 g of the organic phase and 39 g of the aqueous phase as a fraction having a distillation column top temperature of 100 ° C. As a result of GC analysis, 48 g (0.57 mol) of ECR was produced in the organic phase. This corresponds to a yield of 35 mol% based on the raw material NBD.

Comparative Example 3
After performing the same operation as in Example 2 except for total refluxing for 240 minutes, a fraction that was distilled under normal pressure and separated into a distillation column top temperature of 100 ° C. was separated into 64 g of organic phase and 22 g of aqueous phase. Obtained. As a result of GC analysis, 50 g (0.59 mol) of ECR was produced in the organic phase. This corresponds to a yield of 35 mol% based on the raw material NBD.

  ECR is a compound useful as various chemical raw materials, and is useful as a starting material for the production of pyridine or quinoline derivatives, and is also effectively used as a raw material for di-TMP and the like.

Claims (6)

  After maintaining a mixture of normal butyraldehyde and formaldehyde at 5 to 35 ° C. and adding a base catalyst, or after adding formaldehyde and a base catalyst in parallel to normal butyraldehyde maintained at 5 to 35 ° C., A method for producing 2-ethyl-2-propenal, which is heated to complete reflux to complete the reaction, followed by distillation to obtain a fraction containing 2-ethyl-2-propenal.   The method for producing 2-ethyl-2-propenal according to claim 1, wherein the base catalyst is an alkali metal or alkaline earth metal carbonate and / or bicarbonate.   The method for producing 2-ethyl-2-propenal according to claim 1, wherein the base catalyst is added dropwise as an aqueous solution.   The formaldehyde is 0.9 to 1.5 mol and the base catalyst is 0.05 to 0.5 mol with respect to 1.0 mol of normal butyraldehyde. Production method.   The method for producing 2-ethyl-2-propenal according to claim 1, wherein the time for heating to complete the reaction is 0.5 to 3 hours.   The method for producing 2-ethyl-2-propenal according to claims 1 to 5, wherein water is distilled together with 2-ethyl-2-propenal during distillation.