JPH04221342A - Acetic acid 3-ethoxybutyl ester compound and production thereof - Google Patents

Abstract

PURPOSE:To provide acetic acid 3-ethoxybutyl ester which is a new ester compound useful as a solvent, medium, etc.; to clarify the properties, e.g. physical properties and solvent characteristics, of the ester; and to provide a method for profitably produce the acetic acid 3-ethoxybutyl ester from 3-ethoxybutanol and ethyl acetate as raw materials. CONSTITUTION:A new ester compound, 3-ethoxybutyl acetate, was found. The 3-ethoxybutyl acetate can be profitably produced by reacting 3-ethoxybutanol with ethyl acetate in the presence of a porous strong acidic cation exchange resin under a liquid phase condition. The produced new ester compound was identified to be the 3-ethoxybutyl acetate by various kinds of analyses, and the properties of the ester were clarified by the measurement of the physical properties, the solvent characteristics, etc.

Description

Description: TECHNICAL FIELD The present invention relates to a novel ester compound and a method for producing the same. Specifically, the present invention relates to a novel 3-ethoxybutyl acetate useful as a solvent, a solvent, etc., and a method for producing 3-ethoxybutyl acetate using 3-ethoxybutanol and ethyl acetate as raw materials. [Prior Art] Conventionally, 3-
Methoxybutanol and acetic acid 3-methoxybutyl ester, which is an acetylated version of methoxybutanol, have been known. [0003] 3-ethoxybutanol is a similar compound, but there are only a few reports regarding this compound (West German Patent No. 579,651, West German Patent No. 599,836).
(issues, etc.) are not easily available. Furthermore, there has been no report on its ester, acetic acid 3-ethoxybutyl ester, and it was completely unknown until now. Problems to be Solved by the Invention The problems to be solved by the invention are to provide 3-ethoxybutyl acetate, to clarify its physical properties, solvent properties, and other properties; - To provide an industrially advantageous method for producing 3-ethoxybutyl acetate using ethoxybutanol and ethyl acetate as raw materials. [Means for Solving the Problems] The present inventors synthesized 3-ethoxybutanol based on the above patent, and further attempted to synthesize an ester compound thereof, and separated and purified 3-ethoxybutyl acetate. The identification was successful and the present invention was completed. The first aspect of the present invention is acetic acid 3-ethoxybutyl ester represented by the following structural formula 2. ##STR2## The second invention of the present invention provides acetic acid 3, which is characterized in that 3-ethoxybutanol and ethyl acetate are reacted under liquid phase conditions in the presence of a porous strongly acidic cation exchange resin. - A method for producing ethoxybutyl ester. The 3-ethoxybutyl acetate of the present invention is a new substance, and its physical properties, solvent properties, etc. have been measured for the first time and its properties have been clarified by the present invention. The 3-ethoxybutyl acetate of the present invention is a compound that has the characteristics of both an ether and an ester, and its properties as a solvent are classified as high boiling point solvents, and its ability to dissolve various synthetic resins is at a high level. It was revealed that it has physical properties that are comparable to those of 3-methoxybutyl acetate. Utilizing this resin-dissolving power, it is expected to be used as a solvent for paints, inks, resists, etc., and as a reaction solvent for various polymer syntheses. As a result of intensive research on the method of synthesizing the novel compound of the present invention, which is expected to have wide applications, we found that 3-ethoxybutanol, which had been synthesized and isolated by a conventional method, was esterified with acetic acid by a conventional method. can be synthesized,
It has also been found that it can be synthesized by a transesterification reaction between 3-ethoxybutanol and acetic acid ester. As the catalyst for the esterification reaction, sulfuric acid, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid, aluminum alcoholate, etc. can be used. Since this reaction is an equilibrium reaction, a method in which the reaction is carried out while removing produced water from the system is also carried out in order to shift the equilibrium. Benzene, toluene, etc. are used as entrainers that are azeotropic with water. For example, an acetic acid ester is synthesized by reactive distillation in the presence of toluene using a sulfuric acid catalyst at a reaction temperature of 135 to 165°C under normal pressure. - Ethoxybutyl ester can be separated and obtained. Another acetylation method, transesterification, is preferably used as a method for producing 3-ethoxybutyl acetate. Although there are no particular limitations on the acetic acid alkyl ester used in this transesterification reaction, it is preferable to use ethyl acetate because of the advantages described below. As a result of a more detailed study of the transesterification reaction between ethyl acetate and 3-ethoxybutanol, it was found that the transesterification reaction between ethyl acetate and 3-ethoxybutanol produces 3-ethoxybutyl acetate, which is useful as a new ester compound. It has been found that this reaction also produces ethanol as a by-product, and that this ethanol can be advantageously used in the synthesis reaction of 3-ethoxybutanol. [0013] When acetic acid is used as a raw material, expensive materials must be used for the esterification reaction equipment, and ethanol is an expensive raw material, which inevitably increases the cost of the product. This problem could be solved at once by using ethanol. The above transesterification reaction is generally an equilibrium reaction, and various measures have been taken to advance the reaction. However, as a result of intensive investigation into the unknown reaction of transesterification between ethyl acetate and 3-ethoxybutanol,
It was found that this transesterification reaction proceeded easily, and the equilibrium constant was surprisingly found to be 0.8 or more. This means that it is advantageous to increase the reaction rate. Considering that the equilibrium constant of ordinary acetate esters is 0.4 or less, it is said that it is advantageous to adopt transesterification reaction instead of acetic acid reaction with acetic acid in the production of acetic acid 3-ethoxybutyl ester. I have reached a conclusion. [0015] The transesterification reaction proceeds in the presence of a catalyst, and the same catalysts as those for the esterification reaction are used, and examples include sulfuric acid, hydrochloric acid, phosphoric acid, para-toluenesulfonic acid, aluminum alcoholate, titanium alcoholate, etc. . [0016] The reaction method can be a reactive distillation method in which the reaction proceeds while distilling off low-boiling alcohols, or a method can be used in which unreacted components are separated and recovered after the equilibrium reaction and returned to the reactor. . Furthermore, a method is also known in which the reaction is carried out using the above-mentioned catalyst while using an excess of low-boiling point ethyl acetate and distilling off the by-produced ethanol as an azeotrope of ethyl acetate. However, there are many difficulties in implementing these methods industrially. For example, since all of the above catalysts are homogeneous catalysts, a catalyst treatment step is required to remove the catalyst after the reaction and before purifying the desired product. The acid catalyst can be removed as a neutralized salt by adding an alkaline aqueous solution to the reaction solution, but adding water to the system will remove ethanol and 3-ethoxy which are soluble in water to varying degrees. Butanol, ethyl acetate, 3-acetic acid
Not only is the ethoxybutyl ester lost in the wastewater, but significant amounts of water are dissolved in the organic layer containing ethyl acetate, resulting in water-ethanol, water-ethyl acetate, water-ethanol-ethyl acetate, ethyl acetate-ethanol, etc. Boils are formed, making the recovery operation of ethyl acetate and ethanol very complicated. The alcoholate catalyst is either hydrolyzed with water or acid and removed as a hydroxide, or separated under reduced pressure using an evaporator or the like, but in this case as well, there are problems associated with water contamination as described above. Alcoholate catalysts also have the disadvantage that their activity is unstable, such as decomposition due to moisture. If ethyl acetate is used in excess, the by-product ethanol will be distilled out of the system in its entirety as an azeotrope of ethyl acetate. Requires extensive distillation operations. For example, it has been proposed to recover ethanol by a combination of pressurized distillation and normal pressure or reduced pressure distillation, but the operation is complicated. As a result of extensive studies, the inventors of the present invention found that by using a porous strongly acidic cation exchange resin, which is a heterogeneous solid catalyst, as a catalyst, problems of catalyst separation and reaction product liquid due to water contamination could be solved. It has been found that 3-ethoxybutyl acetate can be industrially advantageously produced by solving problems such as separation problems and variations in catalyst activity. [0022] Using a conventional gel-like strongly acidic cation exchange resin as a catalyst, or using a strongly acidic cation exchange resin directly as a catalyst in a conventionally known method that uses a high reaction temperature, has many practical problems such as deterioration of the catalyst. There is a problem with this. In other words, the catalytic activity of ordinary gel-like strongly acidic cation exchange resins is extremely low in a system where only organic substances, which are the raw materials and products used in the present invention, are present. In addition, all of the above-mentioned raw materials have the properties of a "solvent", and in such a system, the above-mentioned catalyst deteriorates significantly and is easily crushed in the reactor. The present inventors discovered that strong acidic cation exchange resins have large differences in catalytic activity and lifespan for transesterification reactions depending on their type, and that a porous cation exchange resin was used instead of the conventionally known gel-like strong acid cation exchange resin. We have discovered that by using a strongly acidic cation exchange resin, it is possible to achieve an extremely high yield and to conduct a stable reaction over a long period of time. The porous strongly acidic cation exchange resin used as a catalyst in the present invention has a skeleton made of styrene-divinylbenzene copolymer, and has many pores (micropores) with a pore diameter of several hundred to several thousand angstroms inside. It is distinguished from conventional gel-like resins in that it has a large internal surface area and pore capacity (porosity). The physical properties of the porous strongly acidic cation exchange resin can be changed significantly by changing the manufacturing conditions, but the catalyst used for the transesterification reaction between ethyl acetate and 3-ethoxybutanol should be at least 0.10 m2/g or more. surface area and 5%
A resin having the above porosity and a degree of crosslinking of 2 to 50 is preferably used. Note that if the degree of crosslinking is too low, the catalyst will have a short lifespan and will deteriorate in a relatively short period of time. Moreover, if the degree of crosslinking is too high, the activity will be low and it will not be practical. These porous strongly acidic cation exchange resins can be prepared by various known methods. for example,
When copolymerizing styrene and divinylbenzene to produce the base material for ion exchange resin, it does not participate in the polymerization and is a good solvent for the monomer, but it has no ability to swell the resulting copolymer. , or introducing sulfone groups into a porous base resin obtained by coexisting with a small non-solvent, such as an alcohol such as tertiary amyl alcohol or secondary butyl alcohol, or an aliphatic hydrocarbon such as isooctane or n-heptane. It can be prepared by In addition, when copolymerizing styrene and divinylbenzene, a linear polymer that does not participate in the polymerization, such as polystyrene, is allowed to coexist, and then this linear polymer is eluted from the copolymer. It can also be prepared by introducing a sulfone group into a base resin. By using the porous strongly acidic cation exchange resin described above as a catalyst, separation of the catalyst becomes unnecessary, water does not get mixed in, and continuous operation becomes very easy, allowing high conversion with a small amount of catalyst. 3-ethoxybutyl acetate can be industrially produced advantageously because the reaction can be carried out stably for a long period of time with almost no decrease in catalyst activity or physical collapse. became. In the present invention, if the molar ratio of ethyl acetate and 3-ethoxybutanol brought into contact with the porous strongly acidic cation exchange resin is not appropriate, the reaction rate will be affected, and the separation of unreacted substances, Since the cost of recovery increases, the ratio is usually 1:0.1 to 10, preferably 1:1 in order to obtain an appropriate space-time yield and reduce the amount of circulation for recovery.
A range of 0.2 to 5 is desirable. The by-produced ethanol is then processed into ethyl acetate and ethyl acetate in the subsequent separation process.
It is separated from 3-ethoxybutanol and 3-ethoxybutyl acetate and can be used as a raw material for the synthesis of 3-ethoxybutanol. The reactor used in the present invention is preferably a tubular reactor capable of being filled with a porous strongly acidic cation exchange resin. The flow of the raw material mixture to the reactor may be either a fixed bed laminar flow or counterflow piston flow type, or a fluidized bed counterflow complete mixing type, and the contact time is 0.2 to 5 hours, preferably 0.2 to 5 hours. Feed at a rate such that it lasts 5-3 hours. The temperature of the reactor is below 100℃, usually 20-90℃
, preferably kept at 30-80°C. At high temperatures of 100° C. or higher, deterioration of the catalyst and by-products of high-boiling substances become significant. Further, the reaction pressure only needs to be large enough to maintain the liquid phase, and usually normal pressure may be used, but the pressure may be increased to 5 kg/cm2 depending on the raw material composition and reaction temperature. The selectivity of 3-ethoxybutyl acetate in the present invention is very high (99% or more). [0030] The present invention will be explained below with reference to Examples, but the present invention is not limited thereto in any way. [Example 1] (Synthesis Example) (2) Alcohol addition reaction 223 g (3.2 mol) of crotonaldehyde and 620 g (13.5 mol) of ethanol are placed in a 2000 ml flask. The reaction apparatus is set in a bathtub cooled to -5°C, stirring is started, and the reaction raw materials are cooled. When the raw material reached a constant temperature, 50 to 60 ppm of sodium hydroxide as a catalyst was added to the total amount to start the reaction. As the sodium hydroxide catalyst, a 5% by weight aqueous sodium hydroxide solution was used. The reaction time was 4 hours. Analysis of the reaction solution showed that the reaction rate of crotonaldehyde was 97%. This reaction solution was poured into a packed column with a height of 40 cm for 50 min.
Distilled below torr to cut out low boiling and high boiling substances.60
213 g of 3-ethoxybutanal in % concentration were obtained. ■Hydrogenation reaction 213g of this concentrated liquid was added to a volume of 3
00ml autoclave in the presence of 2% by weight Raney nickel catalyst under hydrogen pressure of 100Kg/cm2G.
The reaction was carried out at a temperature of 120° C. for 1 hour. It was purified using the same distillation column as in (2) to obtain 125 g of 3-ethoxybutanol with a purity of 98%. ■ 125 g of 3-ethoxybutanol obtained in the acetylation reaction ■ and 1.5 times the mole of acetic acid were mixed with 0.5% sulfuric acid and toluene as an entrainer at a tower top temperature of 9.
The reaction was carried out at 0 to 110° C. while removing water to obtain a crude liquid material. This crude product was purified and distilled to obtain a material with 99.9% purity. (Analysis) The obtained substance was subjected to various analyzes to determine its structure. Infrared absorption spectrum analysis reveals that there are ether bonds and carboxyl groups. In gas chromatography mass spectrometry, C2H
5 O group, CH3 CO group, C2 H5 O (CH3
) It was revealed that it contains a CH group. From the above, it is presumed that in the same way that 3-methoxybutyl acetate is produced by the acetylation reaction of 3-methoxybutanol, 3-ethoxybutyl acetate is produced by the acetylation reaction of 3-ethoxybutanol. Ta. Furthermore, 1 H-
NMR analysis identified this material as acetic acid 3-ethoxybutyl ester. The positions and equivalent numbers of each hydrogen in Structural Formula 3 of acetic acid 3-ethoxybutyl ester below clearly matched the signal elements of the 1 H-NMR spectrum. NMR analysis (1H-NMR, solvent CDCl3) [Chemical formula 3] Signal No. Chemical shift δ Multiplicity Spin coupling constant Number of hydrogens Structural formula above
(ppm)
equivalent hydrogen

Location───────
──────────────────────────
──── 1 1.14
d J=7.1Hz
3H e
2 1.14
tJ=6.3Hz
3H g 3
1.68 q
J=6.2Hz 2H
c4 2.0
s
3H a
5 3.43
m
1H d 6
3.43 q
2H
f 7 4.
1 t
2H b The physical properties of the obtained acetic acid 3-ethoxybutyl ester were measured. Physical properties of acetic acid 3-ethoxybutyl ester [0037] In order to examine the compatibility of the obtained acetic acid 3-ethoxybutyl ester with various solvents, a typical solvent and acetic acid 3-ethoxybutyl ester were mixed at a volume ratio of 1/1. The mixture was placed in a test tube, mixed, and allowed to stand at room temperature to check mutual solubility. As a result, it was completely miscible with the following solvents. Methanol, ethanol, isopropanol, acetone, MIBK, butyl acetate, benzene, toluene, xylene, n-hexane, cyclohexane. The solubility of the obtained 3-ethoxybutyl acetate to various resins was investigated. Take 2g of resin in a 50ml Erlenmeyer flask, add 18ml of solvent,
The mixture was stirred while being kept at 25° C., and after 3 hours it was visually determined whether the resin had melted. The results are shown below in comparison with the case of 3-ethoxyethyl acetate (abbreviated as EGA). Acetic acid 3-ethoxybutyl ester is abbreviated as EBA. [Example 2] A porous strongly acidic cation exchange resin Diaion-PK212 (H type) (registered trademark) (crosslinking degree 6, Continuous operation was carried out using a catalyst with a surface area of 0.15 to 0.20 m2/g and a porosity of 10%. 25.1 wt % of fresh 3-ethoxybutanol was added to a stainless steel jacketed fixed bed tubular reactor filled with 100 ml of the above catalyst swollen with 3-ethoxybutanol at 65° C. and normal pressure. A mixture of 74.9 wt% ethyl acetate at a molar ratio of 1:4 was supplied at a rate of 200 l/hr. As a result of analyzing the reaction product liquid discharged from the reactor by gas chromatography using a conventional method, the composition was found to be 18.2 wt% acetic acid 3-ethoxybutyl ester, 5.2 wt% ethanol,
Ethyl acetate 64.8wt%, 3-ethoxybutanol 1
The content was 1.5 wt%, and the other content was 0.3 wt%. Therefore,
The reaction result was a reaction rate of 3-ethoxybutanol of 54.0%.
, the selectivity for acetic acid 3-ethoxybutyl ester was 99.0%. Although this continuous reaction was carried out for three months, almost no deterioration of the catalyst was observed. [Example 3] Diaion-PK216 (H type) (registered trademark), a porous strongly acidic cation exchange resin having a skeleton made of a styrene-divinylbenzene copolymer that had been sufficiently dried in advance (degree of crosslinking: 8, Continuous operation was carried out using a catalyst with a surface area of 0.15 to 0.20 m2/g and a porosity of 10%. [0042] A stainless steel jacketed fixed bed tubular reactor filled with 100 ml of the above catalyst swollen with 3-ethoxybutanol was heated with 3-ethoxybutanol at 65°C and normal pressure by backflow.
-Ethoxybutanol 87.0wt%, ethyl acetate 13
．． A 0 wt % mixed solution was supplied at a rate of 100 l/hr. The reaction product liquid discharged from the reactor was analyzed by gas chromatography using a conventional method, and the composition was found to be 14.6% by weight of 3-ethoxybutyl acetate and 4% by weight of ethanol.
2 wt%, ethyl acetate 4.9 wt%, 3-ethoxybutanol 76.1 wt%, and other 0.2 wt%. Therefore, the reaction results were 63.0% conversion of ethyl acetate and 99.0% selectivity of 3-ethoxybutyl acetate. Although this continuous reaction was carried out for three months, almost no deterioration of the catalyst was observed. Effects of the Invention The present invention provides a novel acetic acid 3-ethoxybutyl ester, and furthermore provides its physical properties,
Properties such as solvent properties were clarified. Moreover, the present invention provides 3
- Provides an industrially advantageous method for producing 3-ethoxybutyl acetate using ethoxybutanol and ethyl acetate as raw materials.

Claims (2)

[Claims] 1. Acetic acid 3-ethoxybutyl ester represented by the following structural formula 1. [Chemical formula 1] 2. A method for producing 3-ethoxybutyl acetate, which comprises reacting 3-ethoxybutanol and ethyl acetate under liquid phase conditions in the presence of a porous strongly acidic cation exchange resin.