JPS58126884A - Manufacture of carbonic alkylene - 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 The present invention relates to a method for producing alkylene carbonate by reacting alkylene oxide with carbon dioxide. Such reactions are well known to those skilled in the art. ◇Alkylene carbonates are useful as solvents or as raw materials for the corresponding glycols.

Several methods have been disclosed for the single step hydration of alkylene oxides to glycols in the presence of a catalyst and carbon dioxide. It is said that such a method makes it possible to reduce the amount of water used. Removal of excess water is a major expense in conventional hydration methods.

In this method, it has been proposed that carbon dioxide is not consumed or that hydration is carried out using alkylene carbonate as an intermediate.

US Patent No. 3,922,314 discloses a method for hydrating ethylene oxide to ethylene glycol. The process uses a catalyst-free aqueous ethylene oxide solution containing at least 8% by weight of ethylene oxide and at least 0.1% by weight of carbon dioxide (or U.S. Pat. No. 3,629,343). This is disclosed in the specification).

Alkylene oxide is hydrated to glycol under pressure. Preferred catalysts are alkali metal halides or #1
4 Ammonium metal hydroxide 1 Alkali metal recommended charcoal salt) or a further such method is disclosed in JP-A No. 45426 of 1980, in which a molybdenum compound and /or tungsten compounds are used with well-known catalysts such as alkali metal halides, quaternary ammonium or quaternary phosphonium salts, organic halides, and organic amines. The reaction in this method is carried out at 20 to 250°C and 9 times m (
gauge pressure).

The production of alkylene carbonate, in contrast to the hydration of glycols of alkylene oxide, is carried out in the considered prior art without the presence of water. A catalyst and reaction conditions similar to those described above for the hydration of alkylene acids are disclosed.

In U.S. Pat. No. 2,667,497, 15
0~250℃, 65~140kg/cffl (500
~2000 psi) using magnesium or calcium halides.

In U.S. Pat. No. 2,766,258, quaternary
Disclosed are methods using ammonium hydroxide, quaternary ammonium carbonate, and quaternary ammonium bicarbonate. The reaction of this method is carried out at a temperature of 100-225° C. and a pressure of 22-351 Yu/min (300-5000 psU).

In U.S. Patent No. 2,773,070 M11,
Temperature 100-225℃, 21ky/4 (00 psi
), quaternary ammonium halides are used.

In U.S. Patent No. 2,773,881 #1,
An amine is used as a catalyst in the reaction. This reaction is 10
It is carried out at 0-400°C and a pressure greater than 35 kg/d (500 psi).

U.S. Patent No. 2,994,705 by the same applicant;
No. 2,994,704 and No. 2,993,908, substantially the same conditions are used, namely at a temperature of 93.
Alkylene carbonates were converted to the corresponding oxiranes using organic phosphonium halides, organic sulfonium halides, and urea halodropalites as catalysts at ~260 °C and pressures of 8 to 212 kg/ci (gauge). A method of manufacturing from a product is shown.

In U.S. Pat. No. 3,535,341, a method is shown in which hydrazine or its halide is used as a catalyst for the reaction and the reaction is carried out at a temperature of 100 DEG to 250 DEG C. In US Pat. No. 4,233,221, anion exchange resins containing quaternary ammonium groups are shown as effective in gas phase reactions.

In JP-A No. 122,776 of FM355,
It is an organic antimony halide which allows the production of alkylene carbonate from room temperature to 120°C in a water-free mixture.

The reaction of an acclimatized alkylene to the corresponding alkylene carbonate is well known using a catalytic converter at lower temperatures and humidity than those previously used by those skilled in the art, and even in the presence of significant amounts of water. It was shown that it is possible to carry out the implementation. Hydrolysis of alkylene carbonate to glycol can be minimized and the main product is alkylene carbonate. Additionally, the relatively high temperatures traditionally used to produce glycols can instead be used to produce alkylene carbonates;
Moreover, large amounts of glycol, especially glycol with a relatively large molecular weight, are not produced. However, this is the case if the molar ratio of carbon dioxide to alkylene oxide is kept greater than about 1:1 and the partial pressure of carbon dioxide is greater than a preselected value.

The alkylene oxide is prepared in the presence of a suitable catalyst in an active cap at 20
Temperatures higher than 90°C, especially above 90°C, preferably 90°C
~170°C, water is present and the molar ratio of carbon dioxide to alkylene oxide is at least 1:1 and is large enough to provide the required partial pressure of carbon dioxide or selectivity to alkylene carbonate. In some cases, it can react with carbon dioxide to form alkylene carbonate. The pressure at which the reaction is carried out is about 10-200/d (gauge pressure), preferably 3
0~80kl? /cn1 (gauge pressure). Suitable catalysts include quaternary organic ammonium halides and quaternary organic phosphonium halides, organic sulfonium halides, and organic antimony halides, especially methyltriphenylphosphonium iodide, tetraethylammonium bromide, and tetraphenylantimonium bromide. At least one of a group of substances can be used. Corresponding carboxylates can also be used. The amount of catalyst used is generally about 0% per mole of alkylene oxide.
．． Up to 10 moles. Preferably it is 0.02 mol from o, o o i◎ Contrary to prior expectations, even if a considerable amount of water is present, there is no
It is also possible to be present in amounts greater than those used in hydration methods in the prior art. If possible, the production of large amounts of glycols, especially relatively high-molecular-weight glycols, would keep the molar ratio of carbon dioxide to alkylene oxide greater than 1:1;
This is also because it can be avoided by adjusting the partial pressure of carbon dioxide to 1111pjn so as to obtain the necessary selectivity to alkylene carbonate. The effective molar ratio of water to alkylene oxide is about 0.01:1 or more, preferably about 0.1:1.
1 to about 4=1, most preferably 0.1:1 to 2:1
However, this does not mean that it cannot contain even larger amounts of water. Addition of water also increases the rate of alkylene carbonate production.

Conventionally, those skilled in the art have generally understood the reaction of producing alkylene carbonate from alkylene oxide and carbon dioxide in a reaction time of 100 to 300
℃, particularly at temperatures of about 150-225°C. Although not generally detailed, in view of the prior art disclosures. The reaction was carried out substantially in the absence of water. For example, in U.S. Pat. No. 4,233,221, the reactants are compressed and dried by condensing water, so that the moisture content of the reactant gas is very low;
It becomes about 0.2 mol%. Since it was well known that the hydrolysis of carbonates is carried out at high temperatures and with catalysts that are also effective for the direct hydrolysis of alkylene oxides to glycols, one skilled in the art would know that if only carbonates were to be produced, then perhaps It seems that they were avoiding the use of water. Otherwise, hydrolysis to glycol would have been expected.

Here, we have shown that the reaction of alkylene oxide with carbon dioxide to produce alkylene carbonate can be carried out in the presence of water. Alkylene carbonate can be manufactured by minimizing losses due to hydrolysis to glycols, especially relatively high molecular weight glycols. Such methods include carbon dioxide, ethylene oxide, and water obtained by extracting ethylene oxide from a dilute aqueous solution using near-critical or supercritical carbon dioxide. It can also be applied to flows. This reaction can be carried out at lower temperatures than previously thought appropriate, i.e. above about 20° C., and can also be carried out with large capped glycols, especially #J! Significantly higher humidity, ie, above about 90° C., can also be used without producing secondary polymeric glycols. However, the molar ratio of carbon dioxide to alkylene fused is maintained greater than about 1:1, and the partial pressure of carbon dioxide is sufficient to provide the necessary selectivity to the alkylene carbonate.

This reaction can be carried out over a wide range of temperatures above about 20°C, especially about 9°C.
It can be carried out at temperatures above 0°C, in particular from 90 to 170°C. Higher temperatures are preferred since the rate of alkylene carbonate formation is increased.

Total pressure is not a particularly critical variable in this reaction. Typically, the total pressure will be in the range of about 10 to 200 Yu/cdt (gauge pressure). However, the partial pressure of carbon dioxide is very important.

The molar ratio of carbon dioxide to alkylene oxide is at least about 1
:1, can be from 1:1 to 100:1. Usually a ratio greater than 1:1 is chosen, preferably from 1:1 to 10:1. The method of the present invention
When used with near-critical or supercritical carbon dioxide extraction of alkylene oxides, this ratio is 40
:1 to as large as 60:1.

It is of particular importance that under the conditions suitable for the process of the invention, water does not hydrolyze alkylene carbonate to glycols, especially glycols of relatively high molecular weight. It was found that the production of Glyfur can be suppressed by supplying a sufficient amount of carbon dioxide. A person skilled in the art could not have predicted such a result. This is because, in the presence of water and particularly at fairly high temperatures, as used herein, the prior art teaches that water will hydrolyze the alkylene oxide to glycol. In the presence of carbon dioxide, this reaction was thought to proceed by forming alkylene carbonate as an intermediate. For example, U.S. Pat. No. 4,26462
No. 4 and No. 4,117,250, together with U.S. Pat. No. 3,629,343. Judging from the reported quantitative yields of glycol, it does not seem that alkylene carbonate is found in significant amounts in these.

The acceptability of shiriro water has a certain relationship to other operating conditions and selectivity to alkylene carbonate produced.

As shown in the Examples below, effective amounts for direct hydration of alkylene oxides to glycols were determined at relatively low temperatures. Above about 90°C, especially from 90 to 170°C, it is preferred that the molar ratio of water to alkylene oxide is up to about 4:1, most preferably α1:1 to 2=1. The presence of water has a beneficial effect on the alkylene carbonate formation reaction rate, contrary to what would be expected. This effect is even greater when certain catalysts are used.

Particularly preferred catalysts are those in which the bond between the halide atom and the rest of the molecule is ionic rather than covalent, such as quaternary phosphonium octamide.

Catalysts useful in the process of the invention include many that are well known to those skilled in the art. There are many types of useful compounds, but one or more of the group consisting of organic quaternary ammonium octamides or organic quaternary phosphonium octamides, organic sulfonium halides, and organic antimony halides are preferred. included. Corresponding carboxylates can also be used. Examples of compounds that can be used are the following ammonium compounds: tetraethylammonium bromide and tetraethylammonium iodide. As a phosphonium compound,
Examples include methyltriphenylphosphonyl phosphonium bromide and methyltriphenylphosphonium bromide. Sulfonium compounds include trimethylsulfonium iodide and trimethylsulfonium bromide. Antimony compounds are highly effective in the absence of water, but appear to have negative effects when water is present. Typical compounds include tetraphenylantimony bromide and siliphenylantimony dichloride. Particularly preferred catalysts when water is present are methyltriphenylphosphonium dinitride and tetraethylammonium bromide. Among the halides, bromide and nickel are preferred.

The amount of catalyst is comparable to lids used in other methods,
Up to about 0.1 mol of catalyst, preferably 0.001 to 0.02 mol of catalyst, can be used per mole of alkylene oxide, although it is not impossible to use larger and smaller amounts. .

Heretofore, those skilled in the art have recognized that relatively high temperatures of 100° C. and above are suitable for producing alkylene carbonates when water is not present, and for producing alkylene glycols when water is available to hydrolyze alkylene oxides. However, in the method of the present invention, approximately 20°C
Higher temperatures are used, preferably above 90°C, especially from 90 to 170°C.

The reaction producing alkylene carbonate can be carried out in the presence of significant amounts of water. At the relatively high temperatures commonly used in the prior art, the formation of glycols is expected when water is present, and indeed this is the basis for some of the methods described above. As shown below, even when carried out at relatively high temperatures, hydrolysis can be minimized by controlling the molar ratio of carbon dioxide to alkylene oxide and the partial pressure of carbon dioxide. It is possible to produce alkylene carbonate.

The first five examples shown below demonstrate the formation of alkylene carbonate at temperatures below 90°C.

A sample of the test catalyst was placed in a 130 cc cylinder manufactured by Pal Instrument Company. Samples of ethylene oxide and carbon dioxide were charged at -78°C by immersing the cylinder in a dry ice/acetone bath. The bomb was then closed and placed in a 36°C bath, allowing the internal temperature of the bomb to rise to 60°C and allowing the reaction to proceed. Stirring was performed with a magnetically driven disk. After an appropriate period of time, the cylinder was removed from the bath and its contents analyzed. The results of several such tests are shown in Table 1 below.

This example shows that if the temperature is low enough, the presence of water does not produce significant amounts of glycol. Furthermore, it has surprisingly been found that water has a positive effect on the selectivity to ethylene carbonate in the case of some catalysts.

On the other hand, in the case of other catalysts, this price seems to decrease.

Example 2 Effect of water on the catalyst - Various amounts of water were charged into the Pal cylinder and Example 1
The test was repeated. The results are as follows.

The data in Table 2 show that the presence of water generally does not affect the conversion of ethylene oxide to any appreciable extent. The selectivity to ethylene carbonate is reduced by the presence of water when catalyst C is used, and is greatly increased by the presence of water when catalyst C is used. Catalyst C is considered to be more suitable for reaction systems in which the amount of water present is not large.

The ratio of water to ethylene oxide is about 0.55:1, which should be compared to the theoretical ratio of 1:1 in the hydrolysis reaction. Although the catalyst appears to be less effective in the absence of water (see test M2), the performance of this catalyst is improved in the presence of water. It should be noted that in this example, the ratio of water to ethylene oxide was as high as 4:1 when using this catalyst.

Although the process of the present invention is particularly effective in the production of ethylene carbonate, it is also broadly applicable to other oxirane compounds, as shown in the following examples.

The test catalyst and water (if used) were charged to a k 130 cc Pal cylinder. Samples of propylene oxide and carbon dioxide were frozen at -78° by immersing the cylinder in a dry ice/acetone bath. Then close the cylinder and put it in a bath at 36°C until the internal temperature of the cylinder is 3°C.
0'UK rose and the reaction was made to be an additional hit. After an appropriate period of time, the cylinder was removed from the bath and its contents analyzed. (The results of several such tests are shown in Table 6.

*PO=@Propylene** PC=Propylene carbonate**** a = Tetraphenylantimony bromide b = Methyltriphenylphosphonium ester C- Tetraethylammonium bromide 4. ! The test of Example 6 was repeated using 1,2-butylene oxide instead of the propylene oxide. The results of several such tests are shown in Table 4.

Example 5 Test catalyst sample H! 0 and solvent (if used)
The mixture was then charged into a 300 ccll air-heated stainless steel autoclave manufactured by Autoclave Engineers, Inc. and equipped with a forced stirring device. Ethylene oxide and carbon difluoride were charged at -78°C while the autoclave was immersed in a dry ice/acetone bath. The autoclave was then closed, heated to the required reaction temperature, and after a suitable period of time, the autoclave was cooled and the contents analyzed. The results of several such tests are shown in Table 5.

The following examples demonstrate that, contrary to the prior art, high yields of alkylene carbonates can be produced at temperatures above about 90° C. in the presence of significant amounts of water, and the formation of relatively high molecular weight glycols is suppressed. It shows that it can be done.

A series of tests were carried out at temperatures above 90° C. in the presence of various amounts of water. Ethylene oxide, carbon dioxide, water and methyltriphenylphosphonium iodide dissolved in ethylene carbonate were continuously fed into a 1 liter electrically heated autoclave equipped with a stirrer. Liquid preform and unconverted vapor were continuously removed from the autoclave and separated in an external vapor-liquid separator. The composition of the liquid and vapor streams was determined by gas chromatography and the conversion and selectivity were calculated. The results are shown in Table 6. From this table, even when the reaction is carried out at temperatures as high as 170°C,
Although a high yield of ethylene carbonate can be obtained, it can be seen that the presence of water has a greater effect at 170'C than at 130°C. In fact, exams 4o and 4
The results of 1 indicate that conditions can be found in which glycol becomes the major product. In each test, CO,:
The molar ratio of EO is greater than 1:1.

When the molar ratio of CO,:EO is less than 1:1, distinctly different results are obtained, as can be seen from the examples below.

Practice 7 The experimental procedure of Example 6 was repeated to reproduce the CO snow:EO ratio carving test 33. However, the pressure is 25kli'/ff1 (gauge pressure)
The molar ratio of co, :EO was varied from 2.0 to α5. When this molar ratio was 2, a selectivity to ethylene carbonate (EC) of 652% and a selectivity to ethylene glycol (MEG) of 36% was obtained.
In the case of this ratio 05, diethylene glycol (DEG
) is important with a selectivity of 1.4%, but CO,:E
When the O ratio was 2, the selectivity of DRG detected in the product was only 0.8%. From this it is concluded that the molar ratio of CO2:EO is an important factor when it is desired to react saponified alkylene with carbon dioxide in the presence of water to produce alkylene carbonate rather than glycol. To obtain such results, the COI:EO molar ratio should be greater than about 1. The most noisy ratio is selected depending on the amount of water present and the operating temperature.

Example 8 CO! Impact of Partial Pressure 601 The importance of partial pressure can be understood from the results of tests conducted by varying the absolute pressure and partial pressure according to the method of Example 6.

As can be seen from this table, if the partial pressure of carbon dioxide is not kept high enough, a significant amount of glycol will be produced in this reaction, which is undesirable when koji pickling of ethylene carbonate is desired. be. Therefore, temperature, H
, O:EOO ratio, and 001 partial pressure should be adjusted to obtain the required alkylene carbonate selectivity. For example, the molar ratio of water and ethylene oxide in the feedstock is 1:
1, and when the reaction temperature is 160°C, the partial pressure of carbon dioxide should be set to 65 to maximize the amount of ethylene carbonate produced! ? /CI! It should be more than that.

Example 9) (,0: Effect of EOO ratio Example 60
In a series of tests following the procedure, the amount of water was varied and the results in Table 8 were obtained.

According to calculations of reaction rate constants, an increase in the conversion of labeled ethylene from 92% to 97.5% corresponds to an approximately 4-fold increase in the reaction rate.

Thus, surprisingly, the addition of water to a water-free feedstock significantly increases the reaction rate, while the reaction product is still primarily ethylene carbonate.

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Claims (1)

[Claims] A method for producing alkylene carbonate by the reaction of an alkylene oxide with carbon dioxide in the presence of an active lid catalyst and water, the reaction being carried out at a temperature of about 20° C. or higher for at least about carried out at a molar ratio of carbon dioxide to alkylene oxide of about 1:1, a molar ratio of water to alkylene oxide greater than about 1:1, and a carbon dioxide partial pressure sufficient to give the desired selectivity to alkylene carbonate. By,
An improved method characterized by controlling the selectivity to alkylene carbonate and suppressing the production of relatively high molecular weight glycols. (2) The method according to claim 1, wherein the reaction temperature is about 90°C or higher. (3) The method of claim 2, wherein the reaction temperature is about 90°C to about 170°C. (4) The molar ratio of water and alkylene oxide is about 0.01
3. The method of claim 2, wherein: 1 to about 4:1. (5) The molar ratio of water and alkylene oxide is about Q.01
7. The method of claim 6, wherein: 1 to about 2=1. (6) Claim 1, wherein the catalyst is at least one of the group consisting of organic quaternary ammonium halides, organic quaternary phosphonium halides, organic sulfonium halides, and organic antimony halides. The method described in section. (7) The method according to claim 5, wherein the catalyst is an organic quaternary phosphonium halide. (8) The method according to claim 6, wherein the catalyst is methyltriphenylphosphonium iodide. (9) The catalyst is about 0.1 per mole of alkylene oxide.
2. A method according to claim 1, wherein the amount is up to 0 mol. 00 The method of claim 1, wherein the alkylene carbonate is ethylene carbonate.