JPH02255668A - Production of lactone compound - Google Patents

Abstract

PURPOSE:To obtain lactone in suppressed side reaction and high selectivity by subjecting a diol having at least one primary hydroxyl group to vapor phase dehydrogenation reaction using a dehydrogenation catalyst consisting of copper, zinc and alkali metal. CONSTITUTION:A diol (e.g. 1,4-butane diol) having a primary hydroxyl group is subjected to vapor phase dehydrogenation reaction using a catalyst consisting of copper, zinc and alkali metal at 170300 deg.C to provide the lactone compound (e.g.; gamma-butylolactone) useful for solvent, chemical speciality raw material, resin raw material, etc. The above-mentioned catalyst consists of 20-60% (as copper oxide) zinc, 30-95% (as Zinc oxide) zinc and 10010000ppm alkali metal and is preferably prepared by absorbing an alkali metal ingredient as a diluted solution into a CuO-ZnO catalyst obtained by coprecipitation of copper salt and zinc salt, followed by filtration, water washing, drying, molding and calcining.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing lactone compounds.

The lactone compound produced by the production method of the present invention is a cyclic ester compound, and is used as a solvent, a raw material for fine chemicals, a raw material for resin, etc.

In particular, γ-butyrolactone, which is obtained through the dehydrogenation reaction of 1,4-butanediol, is an indispensable solvent used in the polymerization of polyimide and polyphenylene sulfide (pps), which are high-performance plastics that have grown rapidly in recent years. - Demand is rapidly increasing as a raw material for methylpyrrolidone.

[Prior Art] So far, as a method for producing a lactone compound, (1)
Cyclization reaction of carboxylic acids with hydroxyl groups, halogens, or double bonds (2) Oxidation reaction of cyclic ketones and cyclic ethers (3) Reduction reaction of cyclic acid anhydrides (4) Intramolecular hydrocarboxylation reaction of unsaturated alcohols (5) Methods such as dehydrogenation of diols are known [for example, Jerry Mar
Ch.

”Advanced Organlc Chcvlst
ry,” 2nd Editlon, McGRAW-old L
L KOGAKUSHA, LTD., (1977)].

The present invention relates to the diol dehydrogenation reaction described in (5) above.

Methods for preparing the corresponding lactones from diols in the presence of dehydrogenation catalysts are well known.

For example, Oka [Bull, Chem, Soc, Japan]
, Vol. 34.1.12, (1981)] evaluated various supports using a reduced copper catalyst, and A 10 (OH
) reported that compared to SiO2, MgO and ZnO supports are superior in terms of activity and selectivity.

However, even when the most excellent ZnO carrier is used, its selectivity is 95%, which is not industrially sufficient.

Low selectivity means that there are many by-products other than the target substance, and in addition to high raw material costs due to low reaction yields, it also means that the reaction mixture containing many by-products The drawback is that the refining costs to obtain a pure product are also high.

In view of this situation, in a method for producing a corresponding lactone by reacting a diol in the presence of a dehydrogenation catalyst,
We undertook this research with the aim of dramatically increasing that selectivity.

First, as a result of analyzing the conventionally known dehydrogenation reaction of diol using a copper-zinc catalyst, it became clear that the main side reaction was a dehydration reaction. It was hypothesized that this was caused by a trace amount of acid components contained in the water.

Therefore, the inventors of the present invention conducted intensive studies on a method for removing trace amounts of acidic content in the catalyst, and found that by adding a small amount of an alkali metal component, the dehydration reaction, which is a side reaction, can be significantly suppressed, and the lactone reaction, which is the main reaction, can be suppressed. It has been discovered that the selectivity of production is significantly improved, leading to the present invention.

[Object of the invention] The object of the present invention is to provide a gas-phase dehydrogenation reaction of diol,
In producing the corresponding lactones, the objective is to develop a technology that can produce lactones with high selectivity, mainly by suppressing side reactions such as dehydration reactions.

[Structure of the Invention] That is, 1 the present invention provides a method for producing a lactone compound by a gas phase dehydrogenation reaction of a diol having at least one primary hydroxyl group, wherein (a) copper, (b) zinc, and (C) an alkali. A method for producing a lactone compound characterized by using a dehydrogenation catalyst made of a metal.

The method for producing lactone according to the present invention will be described in detail below.

(Raw material diol) Considering the reaction mechanism of the raw material diol used in the method for producing a lactone compound of the present invention, at least one of the two hydroxyl groups must be a -grade hydroxyl group.

Further, the number of carbon atoms in the main chain between two hydroxyl groups needs to be 3 or more, preferably 4 or more, considering the stability of the lactone ring to be produced.

Particularly preferred is the case of four or five. Further, the main chain may have a substituent within a range that does not adversely affect the main reaction.

That is, preferred diols include 1,4-diol represented by the following general formula (I) or 1,5-diol represented by general formula (II) ZZH HO-C-C-C-C-OH.l ) ZZH ZZZH HO-C-C-C-C-C-OH (IriZZZH [However, in the above general formulas (1) and (II), Z is a hydrogen atom, an alkyl group, an aryl group, a halogen atom, hydroxyl group,
represents an alkyloxy group, an aryloxy group, or an amino group, and may be the same or different.

Preferred specific diols include 1,4-butanediol,
These include 1,5-bentanediol, 1,6-hexanediol, 1,7-hebutanediol, 1,4-hexanediol, L,2,4-butanetriol, and the like.

(Dehydrogenation Catalyst) The dehydrogenation catalyst used in the method for producing a lactone compound of the present invention consists of three components: (a) copper, (b) zinc, and (c) an alkali metal.

As mentioned above, the dehydrogenation catalyst consisting of copper and zinc is
well known.

Therefore, the feature of the present invention is that an alkali metal component is further added to the copper-zinc catalyst.

The role of each component is as follows.

(a) Copper exhibits a catalytic action in the dehydrogenation reaction as reduced copper.

(b) Zinc acts as a carrier for copper in (1) as zinc oxide.

(c) Alkali metals are considered to exhibit side reaction suppressing effects.

The copper concentration (as reduced copper) in the dehydrogenation catalyst is between 5% and 7%.
It is preferable to use it in the range of 0%.

When it is lower than 5%, the reaction activity is low, and when it is higher than 70%, the mechanical strength of the catalyst is disadvantageously lowered.

Particularly preferred is a range of 20% to 60%.

On the other hand, the alkali metal to be added to the dehydrogenation catalyst is preferably lithium, sodium, or potassium from the viewpoint of side reaction suppressing effect and cost, and they may be used alone, or in combination of two or three. May be used together.

The amount of alkali metal added is determined depending on the type and amount of trace acid components in the copper-zinc catalyst, and therefore the alkali metal concentration in the catalyst is generally limited. That's difficult. However, the acid component (
Catalysts (including precursors that produce acid components during catalyst preparation and reaction) that are prepared with care are taken to avoid contamination (for example,
As shown in the Examples below, catalysts prepared by specialized catalyst manufacturers, etc.) usually contain an extremely small amount of acid component.

Therefore, it is often effective to add a small amount of alkali metal, and the alkali metal concentration in the dehydrogenation catalyst is usually in the range of 50 ppm to 50.000 ppm, more preferably 100 ppm to 10.00 ppm. ,000p
It is best to use it within the pm range.

If it is lower than 50 ppm, the effect of suppressing side reactions is small;
Moreover, if it is higher than 50,000 ppm, the catalyst activity will decrease, which is disadvantageous.

In addition, since zinc is thought to work as a carrier in the form of zinc oxide, the concentration of zinc oxide in the dehydrogenation catalyst is
It is preferable to use it in the range of 30% to 95%.

There are no particular restrictions on the form of the dehydrogenation catalyst as long as the gas phase reaction can be carried out.

Usually, it is a powder, granules, crumbs, lumps, or pellets.

In addition, a copper-zinc dehydrogenation catalyst is usually obtained by reducing a CuO-ZnO catalyst obtained by coprecipitation of a copper salt and a zinc salt, filtration, water washing, drying, molding, and calcination under a hydrogen stream. .

The alkali metal component, which is a feature of the present invention, may be added at any step of the series of catalyst preparation steps described above.

However, since the alkali metal component is added in a small amount and has high water solubility, it is preferably carried out after the water washing step and before the reduction step in the above series of catalyst preparations.

There are no particular restrictions on the method of adding the alkali metal component, but for example, a method of adding the required amount by absorbing a dilute solution of the alkali metal component into the catalyst after the water washing step and before the reduction step can be considered. .

In particular, the method of adding an alkali metal component to the CuO-ZnO catalyst obtained by calcination is more preferable since it is also effective for removing acid components generated during the calcination step.

(Reaction Conditions) The reaction conditions of the present invention are the same as those for conventional dehydrogenation reactions using copper-zinc catalysts.

The reaction temperature is usually in the range of 170°C to 300°C.

If it is lower than 170°C, the activity is low, and if it is higher than 300°C, there will be many side reactions and the catalyst life will be short, which is disadvantageous.

The reaction pressure is not limited to normal pressure, but may be reduced pressure or increased pressure, as long as the raw material diol and the product lactone are in a gaseous state under the reaction conditions.

However, unless there is a special advantage, it is preferable to carry out the reaction under pressure near normal pressure, which is inexpensive in terms of equipment. There are no particular restrictions on the type of reactor, and either a fluidized bed or a fixed bed may be used.

In order to maintain the activity of the reduced copper of the catalyst and to transport the raw materials and products (both gases), together with the raw material diol,
Hydrogen gas is introduced into the reactor.

The hydrogen gas charging rate is usually 1 to 10.000 N L / Hr, preferably 10
to 1.000 NL/Hr.

Further, the hydrogen gas may contain a small amount of impurities (for example, N2, CH4, N20, etc.) as long as they do not adversely affect the reaction.

The raw material diol is usually charged into a reactor after being gasified.

There is no particular restriction on the feeding speed of diol, but usually,
1 to 10,0OONL/Hr for catalyst IL
, preferably 10 to 1.0 OONL/Hr (all calculated assuming the diol as a gas).

(Purification method) The lactone obtained by the present invention has extremely high reaction selectivity.
The purity of the lactone obtained by condensation is very high.

Therefore, there is no need for particular purification, and it can be used as is for industrial purposes.

However, higher purity lactones can be easily produced by further conventional purification methods such as distillation.

(Reactor) A gas phase reactor with a sample vaporization tube (made of stainless steel, catalyst layer inner diameter -5.15 cm, catalyst layer height -20 cm) was heated in a night bath, and 1,4-butanediol (
(hereinafter abbreviated as 1.4-BG) is vaporized in a sample vaporization tube and introduced into the catalyst layer by a carrier gas (hydrogen).

The reaction mixture gas passes through a cold water trap and then a dry ice/acetone trap to remove the main product gamma-butyrolactone (hereinafter abbreviated as GBL) and unreacted 1.4-BG.
, by-products such as tetrahydrofuran (hereinafter abbreviated as THF), water, etc. are captured in the trap.

(Catalyst pretreatment) After filling all the catalysts into the above reactor, they were heated under hydrogen flow (100%
NL/H), and was sufficiently reduced at 300° C. until no water was produced, and then the reaction (1,4-BG charging) was carried out.

(Evaluation) The product mixture captured by the trap was weighed and analyzed by gas chromatography to determine whether unreacted 1.4-BG
SGBL, THF, etc. were quantified, and the conversion rate and selectivity were calculated.

(Post-treatment) 1. After the charging of 4-BG was stopped and the liquid component captured in the trap no longer came out of the reactor, the catalyst was cooled to room temperature.

Thereafter, the carrier gas was replaced from hydrogen with nitrogen, the catalyst was taken out from the reactor, and the metal concentration in the catalyst was analyzed (measured by atomic absorption spectrometry after decomposition into hydrochloride).

The following can be considered as specific implementation B of the present invention.

(1) The method according to the claims, wherein the alkali metal is at least one element selected from lithium, sodium, or potassium.

(2) The alkali metal concentration in the dehydrogenation catalyst is 50 ppm
50.000 ppm or less.

(3) The alkali metal concentration in the dehydrogenation catalyst is 1100p
The method according to the claims, wherein the content of p is not less than 10.000 ppm.

(4) 1 in which the diol is represented by the following general formula (1),
4-diol or 1,5 represented by general formula (11)
-Diol ZZH HO-C-C-C-C-OH (1) ZZH ZZZH HO-C-C-C-C-C-OH (11) ZZZH [However, in the above general formula (1), (I+) , Z represent a hydrogen atom, an alkyl group, an aryl group, a norogen atom, a hydroxyl group, an alkyloxy group, an aryloxy group, or an amino group, and may be the same or different. How to describe the range.

(5) The method according to the claims, wherein the dehydrogenation catalyst is a dehydrogenation catalyst obtained by hydrogen reduction treatment of a composition obtained by a method of adding an alkali metal component to a CuO-ZnO catalyst.

EXAMPLES Examples and comparative examples are shown below to specifically explain the effects of the present invention, but the present invention is not limited to these examples.

[Comparative Example 1] As an example in which no alkali metal was added to the dehydrogenation catalyst, a reaction was carried out using a dehydrogenation catalyst consisting only of a shell and zinc.

As a dehydrogenation catalyst, a CuO/ZnO catalyst (manufactured by 8Ki Co., Ltd., N211.CuO-containing jil-48%, diameter 5mm 84mm pellets) was used at a reaction temperature of 220°C.
Assuming that the hydrogen charging rate is 2ONL/Hr and the 1.4-BG charging rate is 20mL/Hr (21,0g/H''),
The reaction was carried out at normal pressure.

After 8 hours of reaction, the products captured in the trap were analyzed and the following results were given.

1.4-BG conversion rate (hereinafter abbreviated as CBG) -100,
0 mol% GBL selectivity (hereinafter abbreviated as 5GBL) - 91.3 mol% THF selectivity (hereinafter abbreviated as 5THF) - 0,58 mol% In addition, the metal concentration in the catalyst after the reaction is as follows. there were.

Cu - 42% Znm 46% Li - Not detected (detection limit 0.01%) Na - 16ppm K - 11ppm As described above, when using a catalyst to which no alkali metal component is added, the selectivity to GBL is 91° It was found that the selectivity to THF, which is a side reaction product, was as low as 3 mol%, and as high as 0.58%.

[Example 1] Instead of using the CuO/ZnO catalyst as is, it was immersed in a 0.10% KOH aqueous solution for 10 seconds.
The same experiment as in Comparative Example 1 was repeated, and the following results were obtained.

Cape C 100.0 mol% G S -96.3 mol% GBL STHF-0.24 mol% K -110 pm As described above, when a catalyst containing a potassium component is used, the selectivity to GBL is 96.0 mol%. It was found that the selectivity to THF, which is a side reaction product, was suppressed to 0.24%.

[Example 2] The same experiment as in Example 1 was repeated except that the concentration of the KOH aqueous solution was changed to 0.33%, and the following results were obtained.

C-100.0 mol% G SGBL 99.6 mol% 5 THE-0.13 mol% K -320 ppm [Reference Example 1 Same as Example 1 except that water was used instead of the 0.10% KOH aqueous solution. Similar experiments were repeated and the following results were obtained.

C-100,0 mol% G SGBL-91,4 mol% 5THE-0,57 mol% Li-Not detected (detection limit 0.0 ippm) Na-16p
pm K -11 ppm [Example 3] The same experiment as Comparative Example 1 was repeated except that instead of using the CuO/ZnO catalyst as it was, it was immersed in a 0.30% NaOH aqueous solution for 10 seconds, and the following results were obtained. I got it.

C-100,0 mol% G SGBL-99,7 mol% 5THF-0,10 mol% NNa-250pp [Example 4] Instead of using CuO/ZnO catalyst as it is, 0,30% LiOH aqueous solution The same experiment as in Comparative Example 1 was repeated except that the sample was immersed in water for 10 seconds, and the following results were obtained.

CBG -100,0mol% 5GBL 99.8mol% 5THE-0,07mol% Li -110pDm [Example 5] Instead of using the CuO/ZnO catalyst as it is, 0.42%KOH The same experiment as Comparative Example 1 was repeated except that the sample was immersed in the ethanol solution for 10 seconds, and the following results were obtained.

C 100.0 mol% G SGBL-97.2 mol% 5THF-0.18 mol% K -17Qppm [Example 1 Instead of using the CuO/ZnO catalyst as it was, 0.10% KOH aqueous solution Except for 10 seconds of soaking in
The same experiment as in Comparative Example 1 was repeated, and the following results were obtained.

C-100,0 mol% G SGBL-96,0 mol% S -r HF-0, 24 mol% Cu-37% Zn-40% Lf-0,1 plp pmNa-18p p ■8pm [Example 2] KOH The same experiment as in Example 1 was repeated except that the concentration of the aqueous solution was changed to 0.33%, and the following results were obtained.

C-100,0 mol% G S -99,6 mol% BL S -0,13 mol% HF Cu-38% Z n-40% Li-0,3 ppm Na = 20 ppm K = 290 ppm [Reference Example 1] 0 The same experiment as in Example 1 was repeated except that water was used instead of the 10% KOH aqueous solution, and the following results were obtained.

C-100.0 mol% G SGBL-91.6 mol% s, HF-0.56 mol% Cu ball 37% Zn 41% Li-undetectable Na"w 16 ppm K = 11 ppm [Example 3] Cu O/ The same experiment as Comparative Example 1 was repeated, except that instead of using the Z n O catalyst as it was, it was immersed in a 0.30% NaOH aqueous solution for 10 seconds, and the following results were obtained.

C-100.0 mol% G 5GBL-99.7 mol% 5THF-0.10 mol% Cu-38% Zn 40% Li-Q, ippm Na=270ppm K-13ppm [Example 4] Cu O/Z The same experiment as in Comparative Example 1 was repeated, except that instead of using the n 2 O catalyst as it was, it was immersed in a 0.30% LiOH aqueous solution for 10 seconds, and the following results were obtained.

C-100,0 mol% G SGBL-93 5 mol% 5THF-0,22 mol% Cu=38% Zn=41% Li=260ppm Na-18ppm K-12ppm [Example 5] CuO/ZnO The same experiment as Comparative Example 1 was repeated, except that instead of using the catalyst as it was, it was immersed in a 0.42% KOH ethanol solution for 10 seconds, and the following results were obtained.

CBG ■1oo, o mol% 5GBL-93.5 mol% 5THF-0.22 mol% Cu-37%ppm Zn-41%ppm Li coat 1. Oppm Between Na18E) pm K -150ppm

Claims (1)

[Claims] A method for producing a lactone compound by gas phase dehydrogenation of a diol having at least one primary hydroxyl group, comprising: (a) copper, (b) zinc, and (c) an alkali metal. A method for producing a lactone compound, characterized by using a catalyst.