JP2507246B2 - Method for reactivating carbonic acid ester synthesis catalyst - Google Patents

Description

Detailed Description of the Invention

[0001]

[Industrial application] Carbonic acid esters are important as gasoline extenders, octane number improvers, organic solvents, and as a substitute for phosgene in the production of isocyanates, polycarbonates and various agricultural chemicals and pharmaceutical intermediates. It is a compound. The present invention relates to a method for reactivating a catalyst having triphenylphosphine and copper halide having reduced activity, which are used for the synthesis of a carbonic acid ester by reacting an alcohol with carbon monoxide and oxygen, on a carrier. Is.

[0002]

2. Description of the Related Art International Patent Application Publication No. WO87 / 07601 discloses that alcohol, carbon monoxide and oxygen are vapor-phased in the presence of a catalyst in which a copper halide is supported on a carrier (activated carbon, alumina, titania, silica, etc.). A method for producing a carbonic acid diester to be reacted has been proposed. As a method for reactivating a cupric chloride / activated carbon catalyst, the catalyst is dried under an inert gas atmosphere to remove water, and then the catalyst after drying is inactivated. A method of treatment with hydrogen halide gas diluted with gas or air is described.

Previously, the inventors of the present invention have found that a catalyst having triphenylphosphine and hydrogen halide supported thereon, for example, a general formula Cu (PPh ₃ ) _n X [PPh ₃ = P (C ₆ H ₅ ) ₃ ; x = Halogen; n = 1,
2 or 3] has proposed a catalyst for producing a carbonic acid ester in which activated carbon is loaded with a triphenylphosphine / copper complex (International Patent Application Publication WO 90/15791). No effect was observed even if the reactivation method of 1), that is, the method of drying the catalyst in an inert gas atmosphere and then treating the dried catalyst with an inert gas or a hydrogen halide gas diluted with air was applied. It was

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, a carrier is loaded with triphenylphosphine and copper halide, which have been used in the synthesis of carbonic acid ester by reacting an alcohol with carbon monoxide and oxygen and whose activity has been reduced. It is an object to provide a method for reactivating a catalyst.

[0005]

The method for reactivating a carbonic acid ester synthesis catalyst according to the present invention is a triphenylphosphine having a reduced activity used in the synthesis of a carbonic acid ester by reacting an alcohol with carbon monoxide and oxygen. And a catalyst in which copper halide is supported on a carrier is brought into contact with a hydrogen halide-containing gas in a reducing gas atmosphere, or is treated with a reducing gas in advance and then brought into contact with the hydrogen halide-containing gas. And

The treatment temperature for contacting the catalyst with reduced activity with the hydrogen halide-containing gas under a reducing gas atmosphere is 20.
The temperature is set to 0 to 300 ° C, preferably 200 to 270 ° C. Examples of the reducing gas include H ₂ and CO. A treatment time of 0.5 hours or more, usually about 0.5 to 3 hours is sufficient.

Examples of the hydrogen halide include hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, and aqueous solutions thereof. If hydrogen halide is produced under the processing conditions, halogen or an organic halogen compound is used. May be introduced. The amount of hydrogen halide in the gas is preferably about 0.1-5 mol%. The amount of reducing gas is preferably 1 to 80 mol%, particularly preferably 10 to 70 mol%. GHSV is 50
˜1000 h ⁻¹ , preferably 50 to 500 h ⁻¹ . It is preferable that water vapor be present during the treatment with the hydrogen halide-containing gas under a reducing gas atmosphere. The amount of water vapor in the gas is preferably 30 to 90%. If an aqueous solution of hydrogen halide is used as the hydrogen halide source, hydrogen halide and steam can be supplied at the same time. Further, an inert gas such as N ₂ , He or Ar may be present.

When the catalyst with reduced activity is treated with a reducing gas in advance and then brought into contact with a hydrogen halide-containing gas, the treating temperature with the reducing gas is 150 to 25.
0 ° C. is preferable, the treatment time is 0.5 to 2 hours, and the flow rate of the reducing gas is 0.1 to 5 Nl / hr (GHSV: 14 to 7).
14 hr ^-1 ) is good. The treatment with a reducing gas may be performed in the presence or absence of an inert gas such as N ₂ , He, Ar or the like. The catalyst thus treated with a reducing gas is then contacted with a hydrogen halide-containing gas. The treatment temperature with the hydrogen halide-containing gas is 200 to 300 ° C., preferably 200 to 2
The temperature is 70 ° C., and the treatment time may be about 0.5 to 3 hours.
The hydrogen halide-containing gas preferably has a hydrogen halide content of about 0.1 to 5 mol%,
As other components, it contains an inert gas such as N ₂ , He and Ar. Further, it may contain water vapor, and the content of water vapor in the gas is preferably 30 to 90 mol%. The GHSV is 50 to 1000 hr ^-1 , preferably 50 to 500 hr ^-1 .

The catalyst for carbonic acid ester production to which the present invention is applied comprises triphenylphosphine and copper halide supported on a carrier. 30m surface area as carrier
A porous carrier of ² / g or more is preferable, and examples thereof include activated carbon, titanium oxide, zirconium oxide, niobium oxide, silica, alumina and the like. Examples of the copper halide are copper chloride, copper bromide, copper iodide and the like. The content of copper halide in the catalyst is 2 to 10 w as copper in the copper halide with respect to the carrier.
About t% is preferable. The catalyst may be one prepared by sequentially loading triphenylphosphine and copper halide on a carrier, or a complex synthesized in advance from triphenylphosphine and copper halide, that is, the general formula Cu ( PPh ₃ ) _n X [PPh ₃ = P (C ₆ H ₅ ) ₃ ; x = halogen; n = 1,2 or 3] prepared by supporting a triphenylphosphine / copper complex represented by International patent application publication WO 90/15791). Further, it may be one in which a triphenylphosphine / copper complex is supported on a carrier and which is treated with halogen or hydrogen halide (Japanese Patent Application No. 3-35057). The triphenylphosphine / copper complex can be synthesized from cuprous chloride, cupric chloride and other copper halides and triphenylphosphine or its sodium salt. As a specific means, copper halide is dissolved in a solvent such as ethanol or methylene chloride, triphenylphosphine dissolved in a solvent such as ethanol or methylene chloride is added and reacted in an inert gas atmosphere, and then the solvent is added. Removal gives a copper complex. Supporting and immobilization of a copper complex on a carrier is carried out by dissolving the copper complex in a solvent such as chloroform and supporting the solution on the carrier, or by wetting with a solvent such as a lower alcohol, or in the absence of a solvent. It is carried out by physically mixing with the carrier to immobilize it on the carrier, and then treating and stabilizing it under an inert gas atmosphere.

In the present invention, a carbonic acid ester is synthesized by reacting an alcohol with carbon monoxide and oxygen using a catalyst having triphenylphosphine and copper halide supported on a carrier, and its activity is lowered by its use. The catalyst can be well reactivated. Reactivation of the catalyst may be carried out by switching the reaction step and the regeneration step in the case of a fixed bed type synthesis reaction, or by providing the reaction and regeneration step regions in the case of a moving bed or fluidized bed type synthesis reaction. it can.

As the alcohol as a reaction raw material, an aliphatic alcohol having 1 to 4 carbon atoms, an alicyclic alcohol or an aromatic alcohol is preferable. Monohydric alcohols such as methanol and ethanol are particularly preferable. As the reaction conditions for producing the carbonic acid ester, it is suitable that the reaction temperature is 70 to 200 ° C. and the reaction pressure is atmospheric pressure to 15 Kg / cm ² G. The ratio (molar ratio) of carbon monoxide and oxygen to alcohols such as methanol and ethanol is 1.2 each.
2 and 0.55 to 0.01 (CO / O ₂ ratio: 1/1 to
100/1) is good.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

[0013]

[Catalyst Preparation Example 1] 6.7 g of copper (II) chloride and 19.7 g of triphenylphosphine were each added to 100 m of ethanol.
It is dissolved in 1 l, mixed under a nitrogen atmosphere and mixed at about 70 ° C for about 1
Allowed to react for hours. The reaction product was separated by filtration, washed with warm ethanol and dried to obtain 16.3 g of a triphenylphosphine / copper (I) chloride complex. 2.6 g of the complex was mixed with 15 g of activated carbon in a small amount of ethanol to be immobilized, and then heat-treated at 250 ° C. under a nitrogen atmosphere to obtain a new catalyst (C
u3 wt% content) was prepared.

[0014]

[Comparative Example 1] A catalyst prepared by loading the triphenylphosphine / copper (I) chloride complex obtained in Catalyst Preparation Example 1 on activated carbon (C
Dimethyl carbonate synthesis by reacting u3 wt% with methanol, O ₂ and CO (catalyst usage 3.5 g, reaction pressure 6 Kg / cm ² G, reaction temperature 140 to 150 ° C., GHS
V: methanol 500 hr ^-1, using a total of 1100hr ^-1), the catalyst activity is referred to as reduced catalyst (hereinafter deteriorated catalyst a to about 80% of fresh catalyst) was subjected to regeneration tested. 3.5 g of this deteriorated catalyst a was added to N of 0.3 Nl / hr.
₂ flow, temperature 250 ° C, atmospheric pressure 3% HCl / N ₂
Regeneration treatment was performed with a mixed gas of 0.2 Nl / hr for 2 hours. Table 1 shows the regeneration rate and the regeneration conditions of the catalytic activity (methanol conversion rate) when dimethyl carbonate was synthesized using this regenerated catalyst under the same reaction conditions as described above.

[0015]

[Comparative Example 2] As hydrogen halide, 3% HCl / N ₂
Instead of the mixed gas 0.2 Nl / hr, 3.6% hydrochloric acid water 1.
The deteriorated catalyst a was regenerated under the same conditions as in Comparative Example 1 except that 2 ml / hr was used. Table 1 shows the regeneration rate of catalyst activity and regeneration conditions when dimethyl carbonate synthesis was carried out under the same reaction conditions as in Comparative Example 1 using this regenerated catalyst.

[0016]

Example 1 3.5 g of the deteriorated catalyst a was passed under a flow of 0.3 Nl / hr of H _{2 at} a temperature of 250 ° C. and at an atmospheric pressure of 3% HCl / N.
₂ Regeneration treatment was carried out with a mixed gas of 0.2 Nl / hr for 2 hours. Using this regenerated catalyst, the same reaction conditions as in Comparative Example 1 (catalyst usage 3.5 g, reaction pressure 6 Kg / cm ² G, reaction temperature 14
0 to 150 ° C., GHSV: shows methanol 500 hr ^-1, the reproduction rate and the reproduction conditions of catalytic activity when the dimethyl carbonate synthesis was carried out a total of 1100hr ^-1) in Table 1.

[0017]

Example 2 As hydrogen halide, 3% HCl / N ₂
Instead of the mixed gas 0.2 Nl / hr, 3.6% hydrochloric acid water 1.
The deteriorated catalyst a was regenerated under the same conditions as in Example 1 except that 2 ml / hr was used. Table 1 shows the regeneration rate of catalyst activity and the regeneration conditions when dimethyl carbonate synthesis was carried out under the same reaction conditions as in Example 1 using this regenerated catalyst.

[0018]

Example 3 3.5 g of deteriorated catalyst a was regenerated for 2 hours with 1.2 ml / hr of 3.6% hydrochloric acid water at a temperature of 250 ° C. and atmospheric pressure under the flow of CO of 0.3 Nl / hr. Table 1 shows the regeneration rate and the regeneration condition of the catalytic activity (methanol conversion rate) when dimethyl carbonate was synthesized using this regenerated catalyst under the same reaction conditions as in Example 1.

[0019]

Example 4 3.5 g of the deteriorated catalyst a was regenerated for 1 hour with 1.2 ml / hr of 1.8% hydrochloric acid water at a temperature of 250 ° C. and atmospheric pressure under a flow of 2.4 Nl / hr of H ₂ . Table 1 shows the regeneration rate of catalyst activity and the regeneration conditions when dimethyl carbonate synthesis was carried out under the same reaction conditions as in Example 1 using this regenerated catalyst.

[0020]

Example 5 3.5 g of the deteriorated catalyst a was regenerated for 2 hours with 1.2 ml / hr of 0.5% hydrochloric acid water at a temperature of 250 ° C. and atmospheric pressure under a flow of 0.9 Nl / hr of H ₂ . Table 1 shows the regeneration rate of catalyst activity and the regeneration conditions when dimethyl carbonate synthesis was carried out under the same reaction conditions as in Example 1 using this regenerated catalyst.

[0021]

Example 6 Example 4 except that the regeneration temperature was 200 ° C.
In the same manner as above, 3.5 g of deteriorated catalyst a was treated. Table 1 shows the regeneration rate of catalyst activity and regeneration conditions when dimethyl carbonate synthesis was carried out under the same reaction conditions as in Example 1 using this treated catalyst.

[0022]

[Catalyst preparation example 2] 11.2 g of copper (II) bromide and 19.7 g of triphenylphosphine were each added to 100 parts of ethanol.
It was dissolved in ml, mixed under a nitrogen atmosphere, and reacted at about 70 ° C. for about 1 hour. The reaction product was separated by filtration, washed with warm ethanol and dried to obtain 18.6 g of triphenylphosphine / copper (I) bromide complex. 2.9 g of the complex was mixed with 15 g of activated carbon in a small amount of ethanol to be immobilized, and then heat-treated at 250 ° C. in a nitrogen atmosphere to obtain a new catalyst (C
u3 wt% content) was prepared.

[0023]

[Example 7] A catalyst in which the triphenylphosphine / copper (I) bromide complex obtained in Catalyst Preparation Example 2 was supported on activated carbon (C
Dimethyl carbonate synthesis by reacting u3 wt% with methanol, O ₂ and CO (catalyst usage 3.5 g, reaction pressure 6 Kg / cm ² G, reaction temperature 140 to 150 ° C., GHS
V: methanol 500 hr ^-1, a total 1100hr ^-1) catalytic activity using the makes a regeneration test about reduced catalyst to 80% (deteriorated catalyst b) of fresh catalyst. 3.5 g of this deteriorated catalyst b was passed under H ₂ flow of 0.3 Nl / hr at a temperature of 25
At 0 ° C. and atmospheric pressure, 3.6% hydrobromic acid water 1.2 ml / h
It was regenerated at r for 1 hour. Table 1 shows the regeneration rate of catalyst activity and the regeneration conditions when dimethyl carbonate synthesis was carried out under the same reaction conditions as above using this regenerated catalyst.

[0024]

[Catalyst Preparation Example 3] Triphenylphosphine 17.7 g-
Chloroform 50 ml solution and copper (II) chloride 6.0 g
-A 50 ml solution of ethanol was prepared. 8 g of the above triphenylphosphine-chloroform solution on 15 g of activated carbon
Was impregnated and dried at 100 ° C. under a nitrogen atmosphere. Next, 8 ml of the above copper (II) chloride-ethanol solution was impregnated and dried at 100 ° C. under a nitrogen atmosphere to obtain a new catalyst (Cu3 wt).
% Content) was prepared.

[0025]

[Example 8] A catalyst (C in which triphenylphosphine and copper (II) chloride obtained in Catalyst Preparation Example 3 were supported on activated carbon
u3 wt% contained), dimethyl carbonate synthesis in which methanol, O ₂ and CO are reacted (catalyst usage 3.5 g, reaction pressure 6 Kg / cm ² G, reaction temperature 140 to 150 ° C., GH
SV: Methanol 500 hr ^-1 , total 1100 hr ^-1 )
The regeneration test was conducted on the catalyst (degraded catalyst c) used in the above-mentioned catalyst whose catalyst activity was reduced to about 40% of the fresh catalyst. With 3.5 g of this deteriorated catalyst c under H ₂ flow of 0.3 Nl / hr,
1.8 ml / 3.6% hydrochloric acid water at a temperature of 250 ° C. and atmospheric pressure
It was regenerated for 2 hours by hr. Table 1 shows the regeneration rate and regeneration conditions of the catalytic activity (methanol conversion rate) when dimethyl carbonate synthesis was carried out under the same reaction conditions as above using this regenerated catalyst.
Shown in

[0026]

Example 9 Catalyst 3.5 prepared according to Catalyst Preparation Example 1
g was treated with 1.0 wt / hr of 3.5 wt% hydrochloric acid in a nitrogen atmosphere at 250 ° C. for 3 hours. The catalyst is methanol,
Dimethyl carbonate synthesis in which O ₂ and CO are reacted (catalyst usage 3.5 g, reaction pressure 6.5 Kg / cm ² G, reaction temperature 140 to 145 ° C., GHSV: methanol 500 h
The regeneration test was carried out on a catalyst (degraded catalyst d) whose catalytic activity was reduced to about 30% of the fresh catalyst by using r ⁻¹ , total of 1100 hr ⁻¹ ). This deteriorated catalyst d3.5 g
Regeneration treatment was carried out for 2 hours with 1.2 ml / hr of 0.5% hydrochloric acid water at a temperature of 250 ° C. and atmospheric pressure under a flow of 9 Nl / hr of H ₂ . Table 1 shows the regeneration rate of catalyst activity (methanol conversion rate) and regeneration conditions when dimethyl carbonate synthesis was carried out under the same reaction conditions as the above-mentioned reaction conditions using this regenerated catalyst.

[Table 1]

As is clear from Comparative Examples 1 and 2, even if the deteriorated catalyst is brought into contact with the hydrogen halide-containing gas in an inert gas (N ₂ ) atmosphere, the catalytic activity is not regenerated at all. On the other hand, when the deteriorated catalyst is brought into contact with the hydrogen halide-containing gas under a reducing gas (H ₂ , CO) atmosphere, it is regenerated well.

[0028]

[Example 10] 3.5 g of the deteriorated catalyst a used in Example 1
Was treated with CO (GHSV = 86h ⁻¹ ) at 0.3 Nl / hr for 1 hour at 250 ° C. to reduce it in advance, and then at a regeneration temperature of 250 ° C. under atmospheric pressure, 3% HCl / N ₂ mixed gas 0 .5 Nl / hr (GHSV = 71 h ⁻¹ : HCl = 1.
2%, N ₂ = 98.8%) for 3 hours. When this treated catalyst was used to synthesize dimethyl carbonate under the same reaction conditions as above, the regeneration rate of the catalytic activity was 55%. It was also found that re-activation was achieved even if the catalyst was previously treated with a reducing gas and then contacted with a hydrogen halide-containing gas.

[0029]

EFFECTS OF THE INVENTION The catalyst composed of triphenylphosphine and copper halide whose activity has been lowered in the synthesis of carbonic acid ester can be reactivated, and carbonic acid ester synthesis can be effectively carried out by the combination of the reaction step and the regeneration step. be able to.

Claims (3)

(57) [Claims] 1. A catalyst comprising triphenylphosphine and copper halide, the activity of which has been reduced in the synthesis of a carbonic acid ester by reacting an alcohol with carbon monoxide and oxygen, on a carrier under a reducing gas atmosphere. A method for reactivating a carbonic acid ester synthesis catalyst, which comprises contacting with a hydrogen halide-containing gas at 1, or after being previously treated with a reducing gas and then contacting with a hydrogen halide-containing gas. 2. The method for reactivating a carbonic acid ester synthesis catalyst according to claim 1, wherein the contact temperature with the hydrogen halide-containing gas is 200 to 300 ° C. 3. The method for reactivating a carbonic acid ester synthesis catalyst according to claim 1, wherein the contact with the hydrogen halide-containing gas is carried out in the presence of steam.