JPH013152A - Method for producing glycol esters - 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 method for producing glycol esters, and more specifically, by recovering a specific catalyst and recycling it, deterioration and deactivation of the catalyst can be reduced. This invention relates to a method for efficiently producing glycol esters used as chemical intermediates and solvents.

[Prior art and problems to be solved by the invention] Conventionally, as a method for producing glycol esters, an olefin and oxygen are added to a carboxylic acid using a catalyst consisting of a palladium component, a nitrogen-containing oxide, and a metal halide. A method of introducing and reacting is known. (Japanese Patent Publication No. 45-32413, Japanese Patent Application Laid-open No. 51-82213, etc.) Furthermore, following this, hydrogen is introduced, nitric acid is added to the reduced palladium to prepare the catalyst liquid again, and the catalyst solution is supplied to the reaction. A method (Japanese Unexamined Patent Publication No. 177936/1983) has been proposed.

However, according to these methods, although the catalyst activity is sufficiently high at the beginning of the reaction, when the catalyst is recovered and used repeatedly, the activity of the catalyst gradually decreases, and it is also difficult to regenerate the catalyst, so the production efficiency of glycol esters is significantly reduced. The disadvantage was that it decreased.

[Means for solving problems]

After conducting intensive research to solve the problem of ridges,
It has been found that part of the added halogen generates organic halides during the reaction, which are removed from the reaction system in a subsequent distillation step, resulting in a decrease in the amount of halogen that acts as a catalyst.

Therefore, we have discovered that by replenishing this lost halogen, the activity of the catalyst does not decrease even if the catalyst is used repeatedly, and glycol esters can be obtained in high yield.
The present invention has now been completed.

That is, the present invention includes (A) a palladium component, (B) a metal component of groups rA, IB, UA, nB, VA, ■B, or ■ of the periodic table, (C) a halogen component, and (D) a nitrogen-containing oxide. When producing glycol esters by reacting a lower aliphatic carboxylic acid with an olefin in the presence of a catalyst containing oxygen and oxygen, ■ a step of introducing hydrogen to reduce the palladium catalyst after the reaction ■ the resulting reduced liquid Step of filtering the reduced palladium and the reaction solution ■ Distilling the reaction solution to separate lower aliphatic carboxylic acids and glycol esters (4) Lower aliphatic carboxylic acid is added to the reduced palladium obtained in step (2). Provided is a method for producing glycol esters, which comprises a step of adding an acid, the distillation residue obtained in step (1), a halogen ion source, and a nitric acid ion source to prepare a catalyst solution and introducing it into a reaction system. It is something.

The method of the present invention is to produce the target glycol ester by reacting a carboxylic acid, an olefin, and oxygen using the above-mentioned catalyst, and the carboxylic acid and olefin as reaction raw materials are used to react with the target glycol ester. Various types can be used depending on the type of class.

For example, as a carboxylic acid, the general formula RCOOH (wherein,
R represents a lower alkyl group. )・Old...(1) There are lower aliphatic carboxylic acids represented by the following, and specific compounds include acetic acid, propionic acid, a-acid, and isoacetic acid.

In addition, as an olefin, the general formula %formula%() (In the formula, R1-R4 are hydrogen and lower alkyl groups.

Indicates an aryl group or an alkenyl group. ) is an unsaturated compound having a carbon-carbon double bond represented by R,
is hydrogen or a lower alkyl group, and R2+ R3,R
Preferably, a is hydrogen, specifically ethylene,
There are α-olefins such as propylene and butene-1.

The oxygen is not limited to pure oxygen gas, and may be air or the like, or a mixed gas prepared by diluting oxygen with nitrogen, carbon dioxide, or a saturated hydrocarbon such as methane, ethane, or propane.

The amount of these reaction raw materials to be used may be determined by considering the type of target glycol ester, etc., and the charging molar ratio (charge ratio) of olefin to oxygen is usually 1.0 to 3.0. and preferably 1.6~
2.2, more preferably 1.8 to 2.0. If the charging molar ratio exceeds 3.0, deterioration of the catalyst will be promoted, and if it is less than 1.0, it will fall into the explosive range, which is not preferable.

Next, as mentioned above, the catalyst used in the present invention is (A),
It consists of components (B), (C), and (D), and the palladium component (A) here includes metal haladium as well as inorganic compounds such as sodium palladium chloride, palladium nitrate, palladium acetate, Examples include palladium chloride and palladium bromide, with metal palladium being particularly preferred. Although it is preferable to use these palladium components as they are, they can also be supported on a carrier such as activated carbon. There is no particular restriction on the amount of this palladium component, but it is usually desirable to add it in an amount of 0.001 to 10% by weight based on the solvent.

In addition, (B) components of periodic table 1A, IB, and IIA.

The metal components of group 11B, VA, 1B or 2 are used in a metallic state or as an inorganic compound, and preferred metals are alkali metals and alkaline earth metals.

Examples include copper, manganese, zinc, cobalt, and bismuth. Among these, particularly preferred metals are alkali metals and alkaline earth metals, with lithium being particularly preferred.

The amount of component (B) is usually 0.1 to 15 g atoms per 1 g atom of palladium,
Preferably from 0.2 to 15 gram atoms, particularly preferably 1
~10 gram atoms.

(C) The halogen component is used as an inorganic compound, and the halogen is preferably chlorine. The halogen component may be supplied in combination with the above components (A) and (B), for example, as a halide such as palladium, an alkali metal, or an alkaline earth metal. The amount of this halogen component is generally 0.1 to 15 gram atoms, preferably 0.2 to 5 gram atoms, particularly preferably 1 to 5 gram atoms, per 1 gram atom of palladium.

Next, (D) nitrogen-containing oxides include nitrogen oxides such as NO, NO2°N203, nitric acid, fuming nitric acid, nitrates and nitrites of alkali metals and alkaline earth metals, and alkyl nitrites. Examples include nitrite esters, among which nitrates such as nitric acid, lithium nitrate, and sodium nitrate, and nitrite esters such as ethyl nitrite and propyl nitrite are preferred.

The amount of nitrogen-containing oxide blended is usually 0.1 to 15 mol, preferably 0.2 to 5 mol, per gram atom of palladium.
mol, particularly preferably 1 to 3 mol.

In the present invention, a catalyst consisting of the above components (A) to (D) is dissolved in a lower aliphatic carboxylic acid as a reaction raw material and used as a catalyst solution. That is, the carboxylic acid as a reaction raw material is also used as a solvent.

Using the catalyst solution prepared in this way, carboxylic acid,
Glycol esters are produced by reacting olefins and oxygen. Although this reaction can be carried out under various conditions, the reaction temperature is usually 20 to 120°C, preferably 20 to 80°C.

When the reaction temperature exceeds 120°C, the selectivity decreases, which is not preferable. In addition, the reaction pressure is usually normal pressure to 1゜kg/
ca G, preferably normal pressure to 5 kg/cnG.

When the reaction pressure exceeds 10 kg/cJG, the selectivity decreases, which is not preferable.

The reaction system can be batchwise, semi-continuous or continuous, and the state of the reaction system can be either a liquid phase or a mixture of gas and liquid phases, and the state of the catalyst in the reaction system is Either a homogeneous system or a non-uniform system is possible, but a uniform system is preferable.

A diluent can be added to the reaction system, and for example, an inert solvent such as alcohol or ester, or an inert gas such as saturated hydrocarbon gas, cyclic saturated hydrocarbon gas, or nitrogen gas is used.

The basic structure of the glycol ester obtained by the method of the present invention is of the general formula (III) (R1) (R2)C-C(R3) (R4)500R
6 [In the formula, R+, R2+ R3, R4 correspond to the general formula (II) of the raw material olefin, R5, Rh corresponds to hydrogen or an acyl group (RCO-: this R is the general formula (II) of the lower aliphatic carboxylic acid) (corresponding to R in the formula), and hydrogen is O or 1. ], but may have substituents other than those mentioned above. Note that aldehydes, ketones, etc. are present as by-products of this reaction.

The present invention is carried out using the above raw materials and under the above conditions. FIG. 1 is a flow sheet showing an embodiment of the present invention. As is clear from the figure, an olefin and oxygen are introduced into a catalyst solution containing a raw material carboxylic acid to cause a reaction, and the following steps are carried out sequentially up to step (1). Next, Part ■
A catalyst solution is prepared in the process. In this case, the carboxylic acid used as the solvent may be the one separated in step (1), or a new raw material may be supplied.

After the catalyst solution is prepared in this manner, it is introduced into the reaction system.

By the way, the catalyst used in the method of the present invention can be separated and recovered as follows. First, after the reaction is completed, hydrogen is introduced into the reaction solution to reduce the palladium catalyst to metal palladium, which is then collected by filtration. The hydrogen that should be introduced here is not limited to pure hydrogen gas, but also hydrogen, nitrogen, and helium.

A mixed gas diluted with an inert gas such as methane, ethane, or propane may also be used. In addition, the conditions for introducing hydrogen are not particularly limited as long as they can sufficiently reduce the deteriorated palladium catalyst, but generally the temperature is preferably 20 to 150°C under normal pressure to pressurization. The temperature may be 20 to 80°C, and the time may be about 5 to 120 minutes.

On the other hand, the reaction solution after filtering off the reduced palladium is distilled to obtain products and unreacted raw materials, and the distillation 1] residue is recovered. Ni-MOC-R is used for the distillation residue.

MX (However, M is periodic table 1A, IB, HA.

R represents a lower alkyl group, and X represents a halogen. ) and metal halides, which are used as one of the catalyst components.

Note that the distillation residue may be recovered in solid form by completely distilling the reaction solution, but it is easier to handle if it is recovered in a form that is easy to flow while leaving a part of the product glycol ester. Become.

Further, the nitrogen-containing oxide added to the catalyst solution is consumed during the reaction and hydrogen reduction. Therefore, when metal nitrates are used, they are recovered together with metal halides as distillation residues. These may be recovered by extraction or crystallization instead of distillation. Furthermore, when a nitrite ester is used, the ester residue is recovered as alcohol by distillation. It may be recovered by extraction instead of distillation.

A halogen ion source and a nitrate ion source are added to the thus recovered reduced palladium and distillation residue, and a lower aliphatic carboxylic acid as a solvent is further added to prepare a catalyst solution. That is, the above-mentioned halogen ion source, nitric acid ion source, and solvent are added to the distillation residue and uniformly dissolved, and reduced palladium is added to the resulting solution and stirred to prepare a catalyst solution.

Note that the halogen ion source added to the recovered catalyst includes hydrogen chloride, hydrochloric acid, etc., and the amount added is equivalent to the deficiency in the catalyst concentration. Examples of the nitric acid ion source include fuming nitric acid, nitrogen oxides such as nitric acid NO, N02N203, etc., and the amount added is equivalent to the deficiency in the catalyst concentration.

The reason why there is a shortage of nitrate ions is that when the reaction solution is reduced with hydrogen, they become gases such as NO and NO2, which are removed from the reaction system.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (1) In a 200m2 four-eye glass flask equipped with a stirring blade, a cooler, a thermometer, and a gas inlet tube, 214 g of metallic palladium O, 0.187 g of lithium chloride,
0.148 g of lithium nitrate and 120++ l of acetic acid were added, and the flask was heated and stirred in a 60° C. oil bath to prepare a catalyst solution.

(2) Add 24 m of propylene to the prepared catalyst solution while stirring.
j! Oxygen was introduced into the flask from the gas introduction tube at a rate of 12 mβ/min, and reacted for 2 hours.

(3) Then, stop introducing propylene and oxygen,
30mj of nitrogen! was introduced for 5 minutes at a rate of /min. Next, the introduction of nitrogen was stopped and hydrogen was introduced at 25 mj! /min for 1 hour to reduce the palladium component to metallic palladium. After stopping the introduction of hydrogen, add 30 m7 of nitrogen again!
was introduced for 5 minutes at a rate of /min.

(About 2 mβ of this supernatant liquid was sampled, and the product was analyzed and quantified by gas chromatography.) (4) After reduction, the reduced palladium was left in the flask,
The reaction solution was extracted while being filtered through a glass filter.

(5) The reaction solution extracted in (4) above was distilled under reduced pressure to separate acetic acid and the product.

(6) Add 0.15% hydrochloric acid (36%) to the distillation residue from (5) above.
g1 0.1.6 g of fuming nitric acid and 120 mA of acetic acid were added, and this was transferred to the flask in which the reduced palladium remained, heated in an oil bath at 60° C. and stirred to prepare a catalyst solution again. (About 2 mβ of this catalyst solution was sampled, and the remaining amount of the product was determined by gas chromatography.) The above steps (2) to (6) were then repeated. Table 1 shows the production amount and selectivity of the four reactions.

Table 1 1) PGMA: Propylene glycol monoacetate 2
) PGDA: Propylene glycol diacetate Comparative Example 1 The reaction was repeated in the same manner as in Example 1 except that hydrochloric acid (36%) was not used in step (6). Table 2 shows the production amount and selectivity of the three reactions.

Table 2 1) PGMA: Propylene glycol monoacetate 2
) PGDA: Propylene glycol diacetate Example 2 In Example 1, 0.18% of lithium chloride was added in step (1).
0.255 g instead of 7 g, and lithium nitrate O
, ], 484 δ generation ゎ9. Yu. , 2□8gm, Yoyo step (6) 7 Instead of hydrochloric acid, acetic acid solution of hydrogen chloride (2,9
The reaction was repeated as in Example 1, except that %>1.50 g and 0.25 g of fuming nitric acid was used instead of 0.16 g. Table 3 shows the production amount and selectivity of the five reactions.

Table 3 1) PGMA: Propylene glycol monoacetate 2
) PGD/l: Propylene glycol diacetate [Effects of the invention] As mentioned above, according to the present invention, when producing glycol esters, the reaction can be carried out continuously, and the catalyst does not deteriorate or deactivate. It can be reduced and continuously recycled.

Therefore, glycol esters such as ethylene glycol ester and propylene glycol ester, which are useful as chemicals, solvents, etc., can be obtained in high yield. Furthermore, this method is very effective in practice because the processing operation is extremely simple and there is little loss of palladium in the catalyst.

[Brief explanation of drawings]

FIG. 1 is a flow sheet of an embodiment of the present invention. Procedural amendment (voluntary) June 14, 1986

Claims (1)

[Claims] (A) Palladium component, (B) Periodic table I A, I B,
Group IIA, IIB, VA, VIIB or VIII metal components, (
When producing glycol esters by reacting a lower aliphatic carboxylic acid with an olefin in the presence of C) a halogen component, (D) a catalyst containing a nitrogen-containing oxide, and oxygen, (1) After the reaction, hydrogen is (2) A step of filtering the resulting reduced solution into reduced palladium and a reaction solution (3) A step of distilling the reaction solution to separate lower aliphatic carboxylic acids and glycol esters. (4) A lower aliphatic carboxylic acid, the distillation residue obtained in step (1), a halogen ion source, and a nitric acid ion source are added to the reduced palladium obtained in step (2) to prepare a catalyst solution and react. A method for producing glycol esters, comprising the step of introducing them into a system.