JPH0441447A - Production of butanediol by irradiation of light - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a novel method for producing butanediol.

(Prior art) There are six types of isomers of butanediol, but most of them are manufactured as industrially useful intermediates for organic synthesis. In particular, 2,3-butanediol is used as a raw material for the synthesis of butadiene. It is an extremely important compound. 2,3-butanediol is also used as an antifreeze agent, wetting agent, or softening agent.

1,3-Butanediol is also used as a humectant, preservative or admixture. 1,4-Butanediol is extremely important as a raw material for polybutylene terephthalate ST fat, polyurethane rubber, and the like.

Currently, 2,3-butanediol is produced by using butene obtained through petrochemistry as a raw material, oxidizing it to butylene oxide in the presence of a catalyst, and then producing 2-butanol through hydration or sulfuric acid hydration reaction of butene. It is produced through an extremely complex multi-step process in which methyl ethyl ketone obtained through a dehydrogenation reaction is oxidized to diacetyl in the presence of a catalyst, and then reduced in the presence of a catalyst.

1.3-Butanediol is produced by using acetaldehyde obtained from the same reaction as the above-mentioned 2.3-butanediol, i.e., the hydrolysis reaction of butylene oxide, or from petrochemistry, to produce acetaldehydol, and then producing it in the presence of a catalyst. It is produced by reducing it.

1.4-Butanediol is 1, which is obtained by Reppe reaction using acetylene and formalin as raw materials.
It has been produced by hydrogenating 4-butynediol, but recently it has been produced by hydrogenating and hydrolyzing diacetoxybutene, which is obtained by acetoxylating in the presence of a catalyst using butadiene and acetic acid obtained in petrochemistry as raw materials. It is manufactured using a complex multi-stage process.

On the other hand, there are few studies on the method of producing butanediol directly from ethanol, and only a few cases have been reported. For example, in Japanese Patent Application Laid-open No. 59-128339,
It has been reported that when ethanol is irradiated with ultraviolet light (≧290 nm) from a high-pressure mercury lamp using colloidal zinc sulfide as a photocatalyst, acetaldehyde and 2,3-butanediol are produced along with hydrogen. The main product is hydrogen, and both the selectivity and yield of 2,3-butanediol production are extremely low. In addition, butanediol is produced by radiolysis of an aqueous ethanol solution, for example, in V.

D, Khim, Vys by Miiboroda et al.
, E++er (, 20, 22 (1986)), the selectivity and yield of butanediol production are both extremely low in this method as well.

(Problems to be Solved by the Invention) As described above, the conventional industrial method for producing butanediol is a complicated multi-step process using butene or butadiene obtained through petrochemistry as a raw material. Furthermore, the production method using ethanol as a raw material uses a photocatalyst, the reaction process is complicated, and both the selectivity and yield of butanediol production are extremely low. Therefore, an object of the present invention is to provide a new method for producing butanediol that can eliminate the drawbacks of the conventional production method and easily produce butanediol in a short time with high yield. do.

(Means for Solving the Problems) In order to solve the above problems, in the present invention, butanediol is produced by irradiating ethanol with light in the coexistence of hydrogen peroxide.

The present inventors have already developed a method for directly synthesizing ethylene glycol from methanol with high selectivity under light irradiation by effectively utilizing hydroxyl radicals (OH radicals) generated by photolysis of hydrogen peroxide as a reaction initiation species. (Japanese Patent Application Laid-Open Nos. 1-149743 and 1-266842). Based on this knowledge, the present inventors have conducted intensive studies on a method for producing butanediol that is more advantageous than the conventional method for producing butanediol. The present inventors have discovered that butanediol can be easily produced from ethanol with high selectivity and in a short time without using a photocatalyst at room temperature and pressure by a two-stage reaction, and the present invention has been achieved.

The reaction mechanism of the present invention can be expressed by the following reaction formula.

Light irradiation Hz O! '2 fight OH (+) 2CH,
C110H→C! l3C1[(Oll)C1l(Oll
)CH.

2CH2cm, OH->HOCB2CH! cn2cH,
OR(5) CH, CHOH+CHxCHtOB→CHs
CH(OH)CBzCIIJH (6) That is, hydrogen peroxide is efficiently decomposed by light irradiation to generate hydroxyl radicals (OH radicals), which are reaction initiation species (
Equation 1). This reaction initiating species abstracts hydrogen atoms from ethanol to generate σ-hydroxyethyl radicals (Formula 2) and β-hydroxyethyl radicals (Formula 3).

Two of each of the σ- and β-hydroxyethyl radicals thus generated combine to form 2,3-butanediol (formula 4) and 1,4-butanediol (formula 5), and a-hydroxyethyl radical and β-hydroxyethyl radical combine to form 1,3-butanediol (Formula 6)
Think of it as generating.

In the present invention, hydrogen peroxide containing 27% or more by volume of fishing rod can be used.

The ratio of ethanol and hydrogen peroxide can be arbitrarily determined, but preferably the ethanol/hydrogen peroxide ratio (volume ratio) is in the range of 5 to 200.

In the present invention, the reaction is usually carried out under a nitrogen atmosphere, but it may also be carried out under an inert gas atmosphere or an air atmosphere.

As the irradiation light in the method of the present invention, laser light with a wide wavelength range ranging from vacuum ultraviolet to ultraviolet to visible light, light from a mercury lamp, etc. can be used, but high-intensity ultraviolet laser light is preferably used.

Light irradiation is usually performed at room temperature, but may be performed under heating or cooling if necessary.

The light irradiation time is not particularly limited and varies depending on the irradiation conditions such as the type of light source, but it is preferable to carry out the reaction in a short time. Further, during light irradiation, it is desirable to sufficiently stir the mixture in order to carry out the reaction uniformly.

(Function) According to the present invention, hydrogen peroxide is efficiently decomposed by irradiation with light, preferably ultraviolet laser light having characteristics such as monochromaticity and high intensity, and hydroxyl radicals (OH radicals), which are the starting species of the reaction, are highly Generate with density. In order to efficiently react the hydroxyl radicals (OH radicals) thus generated with ethanol, sufficient stirring is performed at room temperature or under heating or cooling. As a result, ethanol and the generated hydroxyl radical (O
Through efficient reaction of H radical) and efficient dimerization reaction of a-hydroxyethyl radical, butanediol containing 2,3-butanediol as the main product is produced with high selectivity.

(Example) The present invention will be explained in more detail based on examples.

Example 1 Pyrex glass laser photochemical reaction vessel equipped with a synthetic quartz laser light entrance window (volume: 91.5 mL)
Inner diameter: 35.5 mm, length near 0 m+a) was charged with 64 mA (1.09 mall) of ethanol, and stirred for about 15 minutes under nitrogen aeration. Next, while stirring the ethanol, laser f-light (wavelength: 248 nm, pulse energy: 340 mJ) from a KrF excimer laser was applied.
/pulse, oscillation frequency: 16BZ) was irradiated at room temperature.

Simultaneously with the start of irradiation, 30% hydrogen peroxide was added to the ethanol at a rate of 3.4 rnl per hour.

Laser light irradiation was stopped 8 minutes after starting irradiation,
The reaction solution was analyzed. As a result, 2.3-butanediol 1.50 mmol 1.3-butanediol 0.2
5 mmol, 1.

0.21 mmoA of 4-butanediol was produced. At this time, the selectivity for all butanediol production was 980%, and the quantum yield was 0.37. In addition, the main product 2,
The selectivity for producing 3-butanediol was 75.2%, and the quantum yield was 0.29. On the other hand, although the production of hydrogen, methane, carbon oxide, etc. was observed, the amount of these produced was extremely small.

Example 2 Pyrex glass laser photochemical reaction vessel (volume: 91.5 mA) equipped with a synthetic quartz laser light entrance window
, inner diameter +35.5 mm, length near 0 mm) was charged with 64 ml (1,09 mon) of ethanol, and stirred for about 15 minutes under nitrogen aeration. Next, while stirring the ethanol,
Ray f*C wavelength from KrF excimer laser: 248 nm, pulse energy: 340rnJ/
Pulse, oscillation frequency: 16 Hx) was irradiated at room temperature. Simultaneously with the start of irradiation, 30% hydrogen peroxide was added to the ethanol at a rate of 3.4 ml per hour. The laser beam irradiation was terminated 68 minutes after the start of the irradiation, and the reaction solution was analyzed. As a result, 2.3-butanediol 13゜41mmoQ, 1.3-butanediol 3.89
mllon, 1,4-butanediol 0.80mm
oα was generated.

The selectivity for total butanediol production at this time was 89.8%.
, the quantum yield was 0.41. In addition, the selectivity for the production of 2,3-butanediol, the main product, was 66.5% and the quantum yield was 0.30, while the production of hydrogen, methane, carbon oxide, etc. was observed. However, the amount produced was extremely small.

Examples 3 to 5 Pyrex glass laser photochemical reaction vessel (volume: 91.5 m1) equipped with a synthetic quartz laser light entrance window
1. Inner diameter: 35-5 fill, length = 70+aa
+) to ethanol 64,61.56 mff1 (1,09
, 1°04, 0.96 mon) and stirred for about 15 minutes under nitrogen aeration. Next, while stirring the ethanol, it was irradiated with laser light (wavelength: 248 nm, pulse energy: 332 mJ/pulse, oscillation frequency: 16 B) from a KrF echimmer laser at room temperature.At the same time as the irradiation was started, 30% peroxide 5 hydrogen water per hour
．． were added to ethanol at a rate of 4, 8.1, and 14.7 ml, respectively. The laser beam irradiation was terminated 68 minutes after the start of the irradiation, and the reaction solution was analyzed.

Table 1 shows the results regarding the amount of 2,3-butanediol produced, the quantum yield of 2,3-butanediol and total butanediol production, and their selectivity in Examples 3 to 5. Although the production of hydrogen, methane, carbon oxide, etc. was observed, the amount of these produced was extremely small.

Table Results of Examples 3-5 Example 6 Ethanol 225 mA (3,84 mo
1) was added, and the ethanol was stirred for about 30 minutes under nitrogen gas. Next, while stirring the ethanol, it was irradiated with light (mainly at a wavelength of 253° and 7 nm) from a 120 W low-pressure mercury lamp at room temperature. Simultaneously with the start of irradiation, 30% hydrogen peroxide was added to the ethanol at a rate of 5.0 mA per hour. The light irradiation was terminated 7 hours after the start of the irradiation, and the reaction solution was analyzed. As a result, 2,3-butanediol 0.13mg+oaS1.3-butanediol 0.01mmall, 1,4-butanediol 0.
01 mmol was produced. At this time, the selectivity for all butanediol production was 71.8%, and the quantum yield was 0.001.

(Effects of the Invention) According to the present invention, by irradiating ethanol with light in the coexistence of hydrogen peroxide, 2 , 3-butanediol can be produced. Therefore, the method of the present invention has extremely great significance as a new method for producing butanediol.

In addition, in a situation where petroleum resources are expected to be depleted worldwide in the future, there is a method to easily produce industrially useful organic synthetic intermediates such as butanediol from raw materials other than petroleum derivatives such as ethanol. There is a strong desire for the development of
From this point of view as well, the present invention has great significance.

Claims (1)

[Claims] A method for producing butanediol, which comprises irradiating ethanol with light in the coexistence of hydrogen peroxide.