JPS59189936A - Preparation of hydrogenating catalyst of lower hydroxycarboxylic ester - Google Patents

Abstract

PURPOSE:To prepare the titled catalyst having excellent degree of conversion and selectivity, by mixing a silica gel having a specific particle size in an aqueous solution containing a copper/amine complex while applying reducing treatment to the obtained copper-containing silica gel. CONSTITUTION:A fine particulate silica gel having an average particle size of 200mum or less is mixed in an aqueous solution containing an amine complex of copper and the obtained copper-containing silica gel is subjected to reducing treatment to prepare the titled catalyst. This catalyst can efficiently prepare glycol from corresponding lower hydroxyarboxylic ester in excellent degree of conversion and selectivity in an industrially available manner as compared with a known catalyst such as a chromium-contaiing catalyst and can overcome pollution trouble accompanied by the use of the chromium-containing catalyst. In this catalyst, the content of copper supported by the silica gel can be adjusted by selecting the amounts of the copper/amine complex and the silica gel and the ratio of silica gel and copper may be about 1:(0.001-2.0) on a wt. basis.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a catalyst for the hydrogenation of lower hydroxycarboxylic acid esters.

Conventionally, a method for producing a corresponding glycol by hydrogenating a hydroxycarboxylic acid ester in the gas phase has been known, and various proposals have been made regarding catalysts for the hydrogenation.

For example, British Patent No. 575380 describes a copper-chromium catalyst as a hydrogenation catalyst.

It has been proposed to use a copper-silica catalyst obtained by melting copper oxide and silicon dioxide.

In the specification of US Patent No. 209315'9.

act such as chromium, molybdenum or tungsten
It has been proposed to use a copper catalyst containing ivating 5 ubstance -, (oxyalt acid salt).

Further, US Pat. No. 2,094,611 also discloses the use of a copper-chromium catalyst.

However, in the methods using these known hydrogenation catalysts, the hydrogenation reaction of higher hydroxycarboxylic acid esters is mainly targeted.

For example, the hydrogenation reaction may need to be carried out under high pressure of 10 atmospheres or more, or the catalyst system may be complex.

Furthermore, they have some drawbacks, such as the yield and selectivity of the target product not necessarily being sufficiently high.

Furthermore, the mainstream of known catalysts for hydrogenation of hydroxyl carboxylic acid esters is copper-chromium catalysts. However, the use of such ROM-containing catalysts poses problems from a practical point of view. In other words, to efficiently recover chromium from the used chromium-containing catalyst and to recover it so that no chromium remains in the 1B catalyst requires expensive and complicated operations. Although it is not impossible, it is extremely difficult and unsuitable for industrial implementation.

Chromium is highly toxic to the human body even in minute amounts, so 2.
．． In terms of environmental health, 1 because there is a possibility of serious pollution occurring.
Should be avoided. Thus, copper-chromium hydrogenation catalysts have a major drawback: the difficulty of disposing of the spent catalyst.

It is also known that various metals or metal compounds other than copper-chromium can be used as general hydrogenation catalysts. Examples of such metals or metal compounds include metals such as Raney nickel, nickel, cobalt, iron, platinum, haladium, and oxides and sulfides of these metals.

However, not all such generally known metals or metal compounds are equally useful in any hydrogenation reaction. In other words, unless a catalyst suitable for the specific hydrogenation reaction is selected according to the reaction conditions, etc., the specific hydrogenation reaction cannot be carried out efficiently. This is well known. moreover.

It is also well known that there are no established guidelines for selecting such suitable catalysts.

The present inventors conducted research with the aim of developing a catalyst for the hydrogenation of lower hydroquine carboxylic acid esters that exhibits a superior catalytic effect than the conventionally known catalysts mentioned above and does not contain chromium. It's here.

The result is an aqueous solution containing copper ammine complexes.

Mixing silica gel with a specific particle size 1. We discovered that by subjecting the resulting copper-containing silica gel to a reduction treatment, it is possible to produce a catalyst for the hydrogenation of lower hydroquine carboxylic acid esters that meets the purpose.

The present invention has now been completed.

That is, the present invention provides an aqueous solution containing a copper ammine complex,
This is done by mixing particulate silica gel with an average particle size of 200 μm or less and subjecting the resulting copper-containing silica gel to a reduction treatment. A method for producing a catalyst for hydrogenation of lower hydroxycarboxylic acid esters is provided.

The catalyst obtained by the production method of the present invention has a better conversion rate and selectivity than known catalysts such as chromium-containing catalysts, and can efficiently and industrially advantageously produce the corresponding glycol from lower hydroxycarboxylic acid ester. It is a catalyst that can overcome the above-mentioned pollution troubles associated with the use of chromium-containing catalysts.

The aqueous solution containing the copper ammine complex used in the present invention can be produced by a method known per se. For example, it can be produced by adding ammonia to an aqueous solution containing copper ions to make the aqueous solution alkaline. Also.

For example, + (I!) can also be produced by adding copper pieces to aqueous ammonia and passing air through the system.

The above-mentioned aqueous solution containing copper ions can be obtained by dissolving a water-soluble copper compound (including copper salt) in water. Examples of such copper compounds include, for example, copper nitrate, copper sulfate, and copper shialate.

Examples include copper chloride, copper carbonate, and copper acetate. The most preferred copper compound is cupric nitrate.

Advantageously, the silica gel used in the catalyst production method of the present invention needs to be fine particles with an average particle size of 200 μm or less. When silica gel having an average particle diameter of more than 200 μm is used, the amount of copper retained in the silica gel decreases, resulting in a significantly low activity of the resulting catalyst. Further, there is no need to set a special limit on the lower limit of the average particle diameter of silica gel.

It is good to have a thickness of up to about 1 mμ. A more preferable average particle size is about 5 mμ to about 150 μm/l.

Particulate silica gel prepared by any method is useful. Its preparation methods include dry methods such as decomposition of silicon halides and organosilicon compounds, heating reduction of silica sand and coke using an arc, vaporization, and post-oxidation of the silica.

Or a wet method that decomposes sthorium silicate with acid.

I can give an example.

An embodiment of the method for producing a catalyst according to the present invention will be described in detail below.

Water-bathable copper compounds such as those exemplified above 1. For example, nitric acid 2.
Copper is dissolved in water, and concentrated aqueous ammonia is added to the aqueous solution containing the 11 ions of Formation Group 1 in such a manner that the pH of the system becomes about 0 to 11, for example about 1 to about 12. Thus, a deep blue aqueous solution is formed. Fine particles or ultrafine silica gel having an average particle diameter of 200 m2/h or less are added to this deep blue aqueous solution, and the two are sufficiently mixed and brought into contact with each other. Mixing can be carried out under atmospheric or elevated pressure, at room temperature or under heated conditions, e.g.
50℃.

A temperature of about 40° C. to about 100° C. can be exemplified. Thus, a copper-containing silica gel in which multiple ions are supported on the silica gel is formed.
For example, a solid residue obtained by evaporating and drying a system containing silica gel containing 1 is thoroughly washed with water and dried to obtain 1.
Then, the catalyst of the present invention can be obtained by reduction treatment. Concentration treatment can be used instead of the above-mentioned evaporation to dryness. For example, it is also possible to evaporate the liquid at about half the volume, collect the solid residue from this concentrated system by, for example, filtration, and process it in the same manner as above to obtain the catalyst of the present invention.

The above-mentioned evaporation to dryness treatment and concentration treatment can be performed under atmospheric pressure conditions or under reduced pressure conditions. If these processes are still not completed,
It can be carried out at room temperature or under heated conditions, but at temperatures below 0°C.
It is preferable to employ heating conditions such as ˜90° C.

For example, the copper-containing silica gel that can be obtained as described above may be reduced in the presence of hydrogen according to a method known per se.

9 can be carried out by heat treatment. for example,
Approximately 150 to 500°C in hydrogen/air flow.

For convenience, reduction treatment conditions can be exemplified under temperature conditions of approximately 00° C. to approximately 400° C. for approximately 1 to approximately 15 hours. Prior to such a reduction treatment, a preliminary heating treatment can be employed. For example, silica gel containing 10 MF No. 11i1 is placed in air at a temperature of about 00°C to about 800°C, preferably about 00°C to about 700°C, for about 1 to about 10 hours. The preheating treatment conditions for the treatment can be exemplified. In the catalyst produced by the present invention.

The copper content that is supported in the silica gel can be prepared by appropriately selecting the amounts of the copper ammine complex and silica gel used for preparing the catalyst. That]- is
Preferably, the weight of silica gel (silicon dioxide): the weight of copper = ]: about 0.001, and more preferably about 2.0, more preferably 1: about 0.01 to]: about 1 It is about .0.

The catalyst produced in the present invention is produced by hydrogenating a lower hydroxycarboxylic acid ester in the gas phase.

It exhibits an extremely excellent effect as a catalyst for producing the corresponding glycol.

When using the catalyst No. 11 obtained in the present invention, the lower hydroxycarboxylic acid ester that is the above-mentioned reaction raw material can be appropriately selected. Specific examples include methyl glycolate, ethyl glycolate, flohil glycolate, butyl glycolate, methyl lactate, ethyl lactate, propyl lactate, WLJe phthyl, methyl-α-hydroxyphylate, ethyl-α-hydroquine. Examples include lower hydroquine carboxylic acid esters such as butyrate and propyl-α-hydroquine butyrate.

When using the catalyst obtained according to the present invention, the preferable hydrogenation reaction conditions for lower hydroxycarboxylic acid ester are 1
It is as follows.

Reaction temperature "140~300℃, preferably 1.70~2
60°C, more preferably 180 to 230°C Contact time: 0.01 to 20 seconds, preferably 0.11 to 20 seconds
3 seconds reaction pressure crab 0. ]~200 atm, preferably coal 40
Molar ratio of atmospheric hydrogen/hydroxycarboxylic acid ester: 2 or more, preferably 10 to 500 The hydrogenation reaction is carried out using the catalyst obtained according to the present invention.

The reaction can be carried out in any manner in which hydrogen gas and lower hydroxycarboxylic acid ester are brought into contact with each other in the gas phase, and either a fixed catalyst bed method or a fluidized catalyst bed method can be adopted. Furthermore, the reaction can be carried out either batchwise or continuously.

Using the catalyst obtained according to the present invention, such K (low)
& Hydrogenation reaction of hydroxycarboxylic acid esters9 For example, it is possible to obtain ethylene glycol from glycolic acid ester, propylene glycol from lactic acid ester, and butanediol from α-hydroxybutylene 1. can.

The catalyst obtained by this method does not contain chromium, as is clear from its production method. Although it does not contain chromium, the catalyst obtained by the present invention is
The reaction of hydrogenating a lower hydroxycarboxylic acid ester to convert it into the corresponding glycol as described above can be efficiently achieved, and the desired product can be obtained with a high space-time yield (S T' y ). In addition, with many conventionally known catalysts, the target product could not be efficiently produced unless the hydrogenation reaction was carried out at a high pressure of 10 atmospheres or more, whereas when the catalyst obtained in the present invention was used.

Even if the hydrogenation reaction is carried out at a pressure lower than 10 atm,
Another advantage is that the desired object can be obtained efficiently.

Next, Examples, Comparative Examples, and Reference Examples of the present invention will be given.

Example 1 Nitric acid di@.trihydrate (cu(no3)2-3 +t2
o)]-01,2I in 300 tnl of water, add 300 ml of concentrated ammonia water, and p)
(approximately 11-12) to obtain a deep blue solution containing a copper ammine complex. To this deep blue solution, fine particle silica gel (manufactured by Fuji Devine Co., Ltd., 5YLOID) with an average particle size of 2.5μ was added.
150) After adding a suspension of 40I in 450 me of water.

Stirred at room temperature for several hours.

The temperature of the mixture was then raised to about 85°C to about 100°C to evaporate most of the water, and then heated to 120°C for 12 hours.
Dry for an hour. Wash dry items thoroughly with water.

It was dried again in air at 140° C. for 14 hours. The dried product was reduced at 350° C. for 2 to 3 hours in a hydrogen stream.

＼ The catalyst was manufactured in R-circumference. l1llI! The copper content of the medium was about 40 wt%, and the weight ratio of copper to silicon dioxide was about 0.67.

Reference Examples 1 to 3 5 ml of the catalyst prepared according to Example 1 was
Fill a stainless steel reaction tube with nmφ and length of 130 m+.

Catalytic hydrogenation reaction of ethyl glycolate, 5V2
The reaction was carried out at a predetermined temperature under the following conditions: 0000 Jar-1, reaction pressure 6 to 9/cnX-o, hydrogen/ethyl glycolate (molar ratio) 100. The results are shown in Table 1.

Table 1 Reference Example 4 The catalyst 5 me prepared in Example 1 had an inner diameter of 10 m and n+
φ.

A stainless steel reaction tube with a length of 130 mm was filled, and the catalytic hydrogenation reaction of ethyl lactate was carried out at eV 6000 hr.

Reaction pressure 61<y/a/l-G + hydrogen/ethyl lactate (
The reaction was carried out under the following conditions: molar ratio) 60 and reaction temperature 185°C. The results were that the conversion rate of ethyl lactate was 96.2% and the selectivity to propylene glycol was 90.5 L%.

Example 2 Cupric nitrate trihydrate 25311 was dissolved in 750-tnl water, and concentrated aqueous ammonia '750 tnl! was added to adjust the pH to about 11 to 12 to obtain a deep blue solution containing the copper ammine complex. In this deep blue solution, the average particle size lθ~2
A suspension of 0 mμ ultrafine silica gel 100I suspended in 1000 m water was added, followed by stirring at room temperature for several hours.

The temperature of the mixture was then raised to about 85° C. to about 100° C. to evaporate most of the water, and then dried at 120° C. for 16 hours. Wash dry items thoroughly with water.

After drying again at 120°C for 24 hours, it was dried at 200°C in a hydrogen stream.
A catalyst was prepared by reduction treatment at ℃ for 12 hours.

The copper content of the catalyst was about 40 wt%, and the weight ratio of copper to silicon dioxide was about 0.67.

Reference Examples 5 to 7 The sample a5 prepared according to Example 2 had an inner diameter of 10 mmφ,
A stainless steel reaction tube with a length of 130 mm was filled, and the catalytic hydrogenation reaction of ethyl glycolate was carried out at a reaction pressure of 6 to 9/cn.
I・0. It was carried out at a predetermined temperature under the conditions of SV 200001+r-1, hydrogen/ethyl glycolate (molar ratio) 1oo. The results are shown in Table 2.

Table 2 Example 3 Cupric nitrate trihydrate 50/l at 150 rnI! 200 rNJ of concentrated ammonia water was added thereto to adjust the pH to about 11 to 12 to obtain a deep blue solution containing a copper ammine complex. In this deep blue solution,
Add 19.2 g of 0μ microparticle silica gel and leave it at room temperature for several hours! I worshiped it.

The temperature of the mixture was then raised to about 85° C. to about 100° C. to evaporate most of the water, and then dried at ]20° C. for 16 hours. Wash dry items thoroughly with water.

After drying again at 120°C for 24 hours, it was dried at 200°C in a hydrogen stream.
A catalyst was prepared by reduction treatment at ℃ for 12 hours.

The copper content of the catalyst was about 40 wt% and the copper to silicon dioxide weight ratio was about 0.67.

Reference Examples 8 and 9 Catalyst 25me prepared in Example 3 with an inner diameter of 19.4 mm
φ.

A stainless steel reaction tube with a length of 'i'00ηlll- was filled with one reaction pressure of 20K9/cnl・G, Sv
A hydrogenation reaction of ethyl glycolate was carried out at a predetermined temperature under the conditions of 20,000 hr-3 and hydrogen/ethyl glycolate (molar ratio) 100. The results are shown in Table 3.

Table 3 Comparative Example 1 A catalyst B was prepared in the same manner as in Example 1, except that silica gel 19.219 with an average particle size of 250 μm was used instead of silica gel with an average particle size of 100 μm. The copper content of the catalyst was about 4 Qwt%, and the weight ratio of copper to silicon dioxide was about 0.67. Reference Examples 10 to 12 5 ml of the catalyst prepared according to Comparative Example 1! inner diameter 10mm
φ.

Length "r': Fill a stainless steel reaction tube with SOmn+ 9 reaction pressure 6 K9/cnl・(J, 5V2000
0hr-1, hydrogen/ethyl glycolate (molar ratio)] 0
0, given i? A catalytic hydrogenation reaction of ethyl glycolate was carried out at n'1 degree. The results are shown in Table 4.

Table 4 Comparative Example 2 Nitric acid No. 2 lil (cu(No3)2.3H20)
24.22 f: 220m1! A solution of 7 g of zinc nitrate [Zn(NO3)26H20] 29, dissolved in 270 ml of water was mixed therewith.

Then ammonium chromate ((NH4)2- cro
4) A solution obtained by dissolving 45.62 in 1.40 ml of water was mixed to obtain a brown precipitate. Add ammonia to this precipitate solution to adjust the pH to 7, stir for 1 to 2 hours, age, and pass through 11 Ti.
It was dried at 0°C for 15 hours. The dried product was put little by little into a container kept at about 400° C. to carry out thermal decomposition. At this time, the catalyst changed from brown to black. Next, this blackened catalyst was subjected to reflux treatment I441 with hydrogen at 200° C. for 51 tX to obtain a jjlil-chromium qti lead-based catalyst.

Reference Examples 13-15 5ml of the catalyst prepared according to Comparative Example 2! A catalytic hydrogenation reaction of ethyl glycolate was carried out under the same conditions as in Reference Examples L to 3. The results are shown in Table 5.

Table 5

Claims (1)

[Claims] In an aqueous solution containing a copper ammine complex, an average particle size of 200
It is characterized by mixing fine particles of silica gel with a particle size of less than μ and subjecting the resulting copper-containing silica gel to a reduction treatment. A method for producing a catalyst for hydrogenation of lower hydroxycarboxylic acid esters.