JPS5867643A - Preparation of unsaturated acid - Google Patents

Abstract

PURPOSE:To obtain an unsaturated acid in high yield, by calcining a catalyst containing P, Mo and O packed in a reaction tube at a specific temperature while feeding air from one end of the reaction tube, and feeding a raw material gas contianing an unsaturated aldehyde and molecular oxygen from the other end of the reaction tube. CONSTITUTION:An unsaturated aldehyde, e.g. acrolein, in the vapor phase is catalytically oxidized to give the corresponding unsaturated acid, e.g. acrylic acid. In the process, a catalyst containing P, Mo O and an alkali metal, Al, Si, Fe, etc. is packed in a reaction tube, and the catalyst is calcined at 300- 500 deg.C while feeding air or air containing ammonia and/or steam thereto, and a raw material gas is then fed from the other end and reacted in the reaction tube. EFFECT:The catalytic activity is high in the inlet part of the air and gradually reduced to the outlet. However, the raw material gas proceeds in the reverse direction to balance the amount of the reacted raw material in all the catalytic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a method for producing the corresponding unsaturated carboxylic acid from an unsaturated aldehyde and molecular oxygen. ◎ Conventionally, various catalysts have been proposed for the gas phase catalytic oxidation of unsaturated aldehydes, including 1 phosphorus 1 molybdenum and oxygen. , catalysts have shown relatively good performance. Some of the inventors also worked with Tokko ShojO-λJO/js!
0-Kosoi Tei and others proposed a catalyst containing phosphorus, molybdenum, and oxygen. According to research by the present inventors, catalysts containing phosphorus, molybdenum, and oxygen can be fired without circulation, especially when fired under air flow. It exhibits significantly higher activity than other catalysts. However, when calcination is carried out on an industrial scale, a difference in activity occurs between the catalyst in the flowing gas section and the catalyst in the outlet section when the calcination is carried out under air circulation. In other words, if the population part has high activity, the outlet part will have low activity, and if the outlet part is set to have an appropriate activity, the catalyst in the inlet part will be over-calcined and deactivated. It has been found that catalysts with such non-uniform activity cannot be used on an industrial scale.

This is because water vapor, ammonia nitrogen oxide, and other gases or gaseous substances are generated from the catalyst during calcination during catalyst preparation. This is because they are exposed to concave air.

When using catalysts with different activities on an industrial scale,
Generally, a method is adopted in which the catalyst particles are mixed so that the aggregate of the catalyst particles appears to be uniform.The operation of mixing catalysts in this way is extremely complicated. ,
In the case of catalysts containing strong phosphorus and molybdenum, it is practically impossible to adopt this operating method. The present inventors have made it possible to industrially use catalysts containing phosphorus, molybdenum, and oxygen. As a result of research on a method of
By adopting a reaction method in which a raw material gas containing unsaturated aldehyde and molecular oxygen is supplied from the other end of the reaction tube after firing at a temperature of 5 ooc, unsaturated acids can be produced in high yield on an industrial scale. They discovered that the catalyst can be used for a long period of time and completed the present invention.In the method of the present invention, after the catalyst is filled into a reaction tube, it is fired while supplying air. The activity is large at the inlet, and the distribution gradually decreases toward the outlet.The raw material gas containing unsaturated aldehyde and molecular oxygen is in the opposite direction to the air during firing, resulting in a raw material gas with a high concentration of unsaturated aldehyde. is catalytically oxidized in the relatively low activity part, and as the concentration of monounsaturated aldehyde decreases, it is sequentially catalytically oxidized with the catalyst in the high activity part, and the reaction amount is averaged.For this reason, catalysts with different activities Unlike when particles are mixed and homogenized, highly active catalyst particles are not subjected to particularly severe conditions and react evenly over the entire area of one catalyst layer, so it is useful for improving yields and long-term use. Produces good results〇The second feature of the present invention is that it is fired in a reactor.The fact that firing is possible in a reactor is because the catalyst system, whose strength decreases with firing, can be filled before firing, which has a high strength. Powderization of the catalyst is prevented, and the effect is very large. In the method of the present invention, an unfired shaped catalyst containing components attributable to raw materials that are scattered by evaporation or decomposition can be used. In order to reduce the diffusion resistance within the calcined catalyst particles, substances that can be removed by evaporation, decomposition, or combustion are added, molded, filled into a reactor, and heated or calcined. It is also possible to reduce the decrease in the yield of the target product. The catalyst that can be used in the present invention is a catalyst for producing an unsaturated acid by oxidizing an unsaturated aldehyde containing phosphorus, molybdenum, and oxygen. , cesium, lithium, etc. 9 metals 1 Group II metals of the periodic table such as magnesium, calcium, strontium, barium, zinc, cadmium, aluminum, thallium, indium, silicon, titanium, vanadium chromium 1 manganese, iron , cobalt, nickel, aluminum, arsenic, selenium, zirconium, niobium 10 dium, palladium, tin, antimony 1 tellurium 1 tantalum, tungsten, copper, silver 1 lead, etc. 〇The raw material may be hydroxide, oxide, salt, chloride, or free acid. Examples of these are phosphoric acid, molybdic acid, phosphomolybdic acid, ammonium molybdate, ammonium phosphomolybdate monomolybdenum trioxide etc.

An example of the vAIIII method is as follows: a phosphoric acid water joint solution is added to an aqueous solution of ammonium molybdate, and if necessary, compounds of other elements, such as acid, copper nitrate, ammonium metavanadate and saponified germanium are added. ,Ko! Idal: After adding silica, etc. 1 Heat, evaporate to dryness while stirring and dry. After crushing the cake, mold it. If necessary, a carrier can be added to the dry powder or the slurry before that. 0 In addition, It is also possible to add a substance that can be removed during the calcination process, such as stearic acid. ◎ After filling the catalyst obtained in this way into the reaction chamber, calcination is carried out while supplying air from one end. 〇 In the present invention The air used may be dry air. However, if the packing length of the catalyst packed in the reactor is large and the difference between the activity of the catalyst on the outlet side of the firing gas and the activity on the inlet side is too large, 1
Since the effects of the present invention may not be fully exhibited, in this case, preferable results can be obtained by using air containing 5% or less ammonia and/or water vapor as the firing gas.

The amount of air can be varied over a wide range, but the space velocity is 1.
00~10000 //H1- is suitable @The firing temperature varies slightly depending on the catalyst composition, but soo N5ooC
, preferably k13! It is rON1720C. For firing
The time required is preferably 7 to 30 hours.

When producing an unsaturated acid by the method of the present invention, it is supplied from the other end of the tube. As the raw material gas, a mixed gas of acrolene or monomethane and molecular oxygen, such as air, is used. Water vapor, carbon dioxide gas, etc. may be introduced as a diluent. In particular, the presence of water vapor has a positive effect on improving the unsaturated aldehyde conversion rate and unsaturated acid selectivity.
1% is appropriate, and 1 is particularly preferable. The reaction pressure can be changed from normal pressure to several atmospheres.
C is appropriate. The gas hourly space velocity varies depending on the reaction pressure and reaction temperature, but JOO~/Q000//Hr is suitable.6 Below, examples and comparative examples are given to explain the method of the present invention in more detail. The ratio is as follows. In addition, the part indicates the overlapping part.

Example 1 After adding and dissolving 117 parts of ammonium metavanadate -l! Attack I! l! 794 parts of kelma dioxide, then 736 parts of potassium nitrate and 3
7,741 parts of ferric nitrate was dissolved in 1,000 parts of pure water and 700 parts of pure water were added one after another, and the mixture was stirred while drying on the evaporation frame for 0/JOC%/A hours and then pulverized. A lubricant was mixed with this powder, which was then pressure-molded.〇While being supplied, the temperature was raised to yttoc at 4'07C/H and maintained for 1 hour.

After baking, the temperature of the reactor was lowered to OC. ◎Capacity: 13% methachlorene, % empty: 4t'Zf bomb, 10% water vapor.
%, nitrogen a & 7% raw material gas at a space velocity of 100/
/Hr after supplying air in the opposite direction to that during firing,
Gradually increased to 90 cm 5 m 0 methachlorolene conversion rate 11/
%, a slow methacrylic selectivity of 74%, and a single stream yield of methacrylic acid of 4.0%.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the raw material gas was supplied in the same direction as the dry air supply during firing in Example 1. As a result, the temperature of the catalyst layer near the raw material gas inlet became constantly high, and there was a risk of deterioration of the catalyst and damage to the reactor, so the reaction was immediately stopped. Comparative Example - Unfired catalyst obtained in Example 1 In the firing furnace, dry air is supplied at a space velocity of /000//H.
After raising the temperature with C/H, it was fired for 5 hours in JIOTC.After the firing was completed, it was taken out and charged into the reaction. Reaction temperature 9
The same raw material gas as in Example 1 was supplied at 0C. However, when the catalyst was taken out from the O reactor which could not be adjusted to the appropriate conditions by increasing the pressure, there were a large number of catalysts that were broken into small pieces □ Example Kobala ammonium tholybdate,? 0005f, 4
It was dissolved in 72,000 parts of DC pure water, and to this was added 94 parts of Jr.
Then, 317 parts of ammonium metavanadate was added. Further, an aqueous solution containing 6 parts of copper nitrate and cesium nitrate was added, and the mixture was kept at 1θC for 1 hour with stirring.
Saponified tin 10? The resulting slurry was evaporated to dryness, dried in □1 Joc for 74 hours, and then pulverized and pressure molded.

The obtained molded product has an inner diameter of 1117 m and a length of 6 m.
The reaction tube was filled with air containing 13% water vapor at a space velocity of /! The temperature was raised at the rate of JOC/H while being supplied at 00//H, and fired for 70 hours at JEIC.After the firing, it became humid and the volume was increased to 20% by volume.
% raw material gas [When the air was supplied at a space velocity of 100//H in the opposite direction to the air supplied during calcination, the methacrylate conversion rate S was 1% and the methacrylic selectivity was 1% at 5 oocc per reactor.
0%, methacrylic acid yield @ 6 times was obtained 〇Comparative example J The same procedure as in Example- was carried out except that the raw material gas was supplied in the same direction as the gas supplied during firing in Example-. . As a result, results were obtained with methacrylic acid conversion of 111% to 0%, methacrylic acid selectivity of 429%, and methacrylic acid single flow yield of S73%.The temperature of the catalyst layer at this time was measured 12 Figure 1
Figure ○/(F') The vertical axis indicates humidity, and the direction of the arrow 1 indicates the high temperature side. The horizontal axis 41 represents the length direction of the catalyst layer filled in the reaction tube. A% represents one end of the catalyst filling part and 8 parts represents the same end. The firing gas is supplied in the direction of A-4B, and the raw material gas is also the same as A-4B (supplied in the direction of Fl. Actual 1IAa is The humidity of the medium layer and @b indicate the reactor bath temperature at that time.In this way, in the reaction method of Comparative Example J, the reaction is mainly in the catalyst section filled at the inlet of the raw material gas. Example 6: It can be seen that the entire catalyst is not used equally. J: After dissolving part of ammonium paramolybdate in 1000 parts of pure water humidified with OC, 1 s of ammonium metavanadate was added and dissolved. Next, after mixing l!f% phosphoric acid/439., 4θ% arsenic acid 10/part, a mixed aqueous solution of copper nitrate/?/part and potassium nitrate/IIJg, and 344 parts titanium dioxide were mixed in order. at a temperature of 3
After holding for an hour with stirring, the resulting cake was evaporated to dryness. The resulting cake was dried at rt/30C for 16 hours, then ground and pressure molded.

The inner diameter of the obtained molded product is J′X! I! I/m, a reaction tube with a length of 6 m was filled with dry air at a space velocity of s, o o.

//while supplying at Hr/ at the rate of IC/H
◎Then, ice island% aq%
and air containing ammonia aO4%I at space velocity/0
00//Hr while increasing the temperature at a rate of JjC/Hr %J l Baked in OC for 11 hours, cooling down to 0C, volume of 1 month, air*'zg outside, and the composition of the attack from the steam room. Space velocity of raw material gas II 00
//Hr While supplying air in the opposite direction to the air supplied during calcination, the humidity was gradually raised to 29 kCO). At a temperature of The obtained □Continue the reaction and after tao time nlJ, the conversion rate to methacine zAJ
%, methacrylic acid selectivity f 41% 1 Same yield 114% was obtained □ Example Ammonium molybdate 5oooHe and 0 then zs% phosphoric acid dissolved in pure water zoooW1 heated to OC
After mixing 43 parts, 40% arsenic acid aqueous solution/41 parts was added.
After adding a mixed aqueous solution of 16 parts of potassium salt and cesium nitrate, 3 J of ammonium metavanadate was added.
L15% Then, antimony trioxide*1J8IS was added and evaporated to dryness while stirring.The resulting cake was pulverized and supported on a silica-alumina carrier.The resulting catalyst was packed into a reaction tube with a length of Jm. After a
Air containing S% water vapor at a space velocity of 900 //Hr
While supplying it! 1 at 53110C with rc/Hr
When the reaction was carried out in the same manner as in Example 3 and the reaction temperature was 3-00 after calcination for 0 hours, the conversion rate of methacrysene was obtained! A 10%% methacrylic acid selectivity S of 50% and a methacrylic acid yield of 7% were obtained ◎ Example S VI in which 3000 parts of rose molybdenum and ammonium was dissolved in 1000 parts of pure water heated to OC ! %S! Assault/4
Added 40 parts of arsenic acid and stirred thoroughly. 1. Added an aqueous solution of copper nitrate ZS, part Z and 714 parts of potassium nitrate and evaporated to dryness while stirring. The resulting cake After pulverizing and mixing with a lubricant, the material was press-molded. The obtained molded product was filled into a reaction tube with an inner diameter of 2.
5. .

While supplying at
The humidity was raised to C and held for an hour. Then, the supply of drying air is reduced to the space velocity / j 00 //Hr and the heating rate is reduced! The reaction was carried out in the same manner as in Example I, except that the temperature was raised to JlOC at tU/H and the temperature was increased to 1°C for 8 hours.
A methacrylic ea selection rate of g&1% and a yield of 30% were obtained.

Example 4 Ammonium paramolybdate! After dissolving 00 in pure water iooom, add a portion of ammonium metavanadate and dissolve it.Furthermore, add an aqueous solution of ferric nitrate qyo4I81S1
Next, 3.14 parts of water glass was added. The catalyst was quickly evaporated to dryness while stirring. After filling the obtained catalyst into a reaction tube with an inner diameter of 2 j m/m% and a length of 3 m, water vapor aOZ was added. % at a heating rate of 1°r/H while passing air at a space velocity of 00//H.
The temperature was raised to 40°C and maintained for 1 hour.

The following reaction was carried out in the same manner as in Example 1. However, methacrysene was used instead of methacrysene, and the reaction temperature was
The aerial velocity of 3C1 was set to 200//H. As a result, the acrylic acid conversion rate was 939%, and the acrylic acid selectivity was Smu01&
, the numerical value of acrylic sea bream yield watt% was obtained◎

[Brief explanation of the drawing]

The drawing shows the temperature distribution of the catalyst layer in the reaction of Comparative Example J, where the vertical axis is temperature and the horizontal axis is Oa, which represents the length of the catalyst layer.
is the temperature of the catalyst layer %b is the reactor bath humidity 0

Claims (1)

[Claims] (1) When producing a corresponding unsaturated acid by vapor phase catalytic oxidation of an unsaturated aldehyde, phosphorus, molybdenum and #I
Fill the reaction tube with a bulky catalyst and supply air from the end of the tube to 300~! A method for producing an unsaturated acid σ1 characterized by supplying a raw material gas containing an unsaturated aldehyde and molecular oxygen from the other end of the reaction tube after firing at r00c. Ammonia and/or
or containing water vapor f: The manufacturing method according to claim 1. (3) The catalyst is phosphorus, molybdenum% oxygen and alkali metals, metals from group Ⅰ of the periodic table, aluminum, thallium, indium, silicon, titanium, vanadium, lithium,
A catalyst consisting of at least one selected from manganese, iron, cobalt, nickel, germanium, arsenic, selenium, zirconium, niobium, tetradium, palladium, tin, antimony, tellurium, tantalum, one tungsten, one copper, one silver, and lead. The manufacturing method O according to claim 1 or 1, which is