JPS6021580B2 - Manufacturing method of methacrylonitrile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing methacrylonitrile by gas phase catalytic reaction of tertiary butanol, molecular oxygen and ammonia.

More specifically, the present invention relates to a method for producing methacrylonitrile by a gas phase catalytic reaction of tertiary butanol, molecular oxygen, and ammonia using a catalyst mainly composed of molybdenum, bismuth, antine, and nickel. isobden,
The production of methacrylonitrile by the reaction of molecular oxygen and ammonia, that is, the ammoxidation reaction of isobutene, is well known, and various catalysts have been reported as useful catalysts for this reaction.

For example, molybdenum bismuth described in Hakama Kosho 38-Shigeru 3611 and Samurai Kosho 39-10111.
Antimony-based catalyst and improvements thereof Samurai Kosho No. 39-26391, Hakama Kosho 48-15283
Examples include catalysts described in the above publication. However, there are almost no reports on a method for producing methacrylonitrile by ammoxidation reaction of tertiary butanol. Isobutene, a raw material for the synthesis of methacrylonitrile by the known ammoxidation reaction, is usually obtained by extracting only highly reactive isobutene from the residue from which butadiene is extracted from the C4 fraction obtained by cracking naphtha, that is, subvent B. It is obtained by absorbing sulfuric acid and dehydrating the resulting tertiary putanol.

Therefore, it would be economically advantageous if tertiary butanol, which is less expensive before dehydration, could be used as a raw material for methacrylonitrile synthesis than isobutene. Additionally, there is a possibility that Tarsia IJ-butanol can be obtained relatively inexpensively as a by-product of propylene oxide produced by the Halcon method. On the other hand, what is important in the synthesis of methacrylonitrile by gas phase catalytic ammoxidation reaction of tertiary butanol is that the dehydration reaction and ammoxidation reaction of tertiary IJ-butanol are efficiently carried out using the same catalyst. From this perspective, the present inventors have investigated various methods for producing methacrylonitrile through the ammoxidation reaction of tertiary butanol. It was discovered that the catalyst has the ability to efficiently proceed with the reaction and produce methacrylonitrile in high yield.

The present invention has been achieved based on such knowledge. That is, the present invention provides a method for combining Tarsia IJ-butanol with oxygen and ammonia, molybdenum, bismuth, antimony and nickel, and at least one element selected from the group consisting of sodium, potassium, rubidium and cesium, or further with phosphorus. This is a method for producing methacrylonitrile, which is characterized in that the reaction is carried out at high temperature using an oxide composition containing the following as a catalyst. The content of the constituent elements in the catalyst of the invention can vary over a wide range.

Preferably, the catalyst composition falls within the range expressed by the following empirical formula. M○, 2BIaSb state icPdAe○
f (However, A is at least one element selected from the group consisting of Na, K, Rb and CS, and the subscripts a, b,
c, d, e, f indicate atomic ratio; when Mo=12, a=
3~1fu b=1.5~15, c=1~IQ d=0~
5, e=0.3 to 5, and f are numbers corresponding to the oxides produced by the combination of the above components.

) The catalyst of the present invention can be produced by any known method.

As a raw material for the molybdenum component, molybdenum trioxide, molybdic acid, ammonium molybdate, etc. can be used.

As a raw material for the bismuth component, bismuth trioxide, bismuth nitrate, nitric oxide of metal bismuth, etc. can be used.

As raw materials for the antimony component, antimony trioxide, antimony tetroxide, antimony pentoxide, nitrate oxide of antimony metal, potic acid of antimony, organic acid salts, etc. can be used.

As the raw material for the nickel component, nickel oxides, hydroxides, nitrate oxides of metallic nickel, and the like can be used.

Phosphoric acid is preferably used as a raw material for the phosphorus component.

As raw materials for the sodium, potassium, rubidium, and cesium components, oxides, hydroxyl analogs, nitrates, and the like of each component can be used. The catalyst of the present invention can be produced by mixing these catalyst brides to a desired composition ratio, drying, and firing. Here, the conditions are important for imparting a predetermined activity to the catalyst.

The catalyst is heated to zero at a temperature of 400°C to 900°C in the presence of oxygen.
．． Preferably, the mixture is heated for 1 hour to 5 hours. Although the catalyst of the present invention can be used without a carrier, it is generally advantageous to include silica, alumina, titania, etc. as a carrier in an amount of 10 to 9% by weight based on the total catalyst weight.

The catalyst may be shaped into pellets and used in fixed bed reactions, or it may be shaped into fine particles and used in fluidized bed reactions.

The reaction of the present invention is carried out by sending a mixed gas of tertiary butarol, oxygen, and ammonia to the catalyst layer.

Air is preferably used as the oxygen source. Nitrogen, carbon dioxide, steam, saturated hydrocarbon, etc. can be used as a diluting gas if necessary. The gas supplied to the reactor preferably has an oxygen/tertiary butanol molar ratio of 1 to 5, particularly 2 to 4, and an ammonia/tertiary butanol molar ratio of 1 to 5, particularly preferably 1 to 2.

Part of the oxygen supplied is supplied with tertiary butanol.
A part or all of the ammonia to be fed downstream from the feed port may be fed upstream or downstream from the tertiary butt/oil feed port.

In some cases, this may increase the yield of the desired product. During the reaction, water vapor can be added for the purpose of suppressing combustion of ammonia, but this is hardly necessary in the present invention.

Even if added for this purpose, a water/tertiary butanol molar ratio of 2 or less is sufficient. The reaction temperature was 30
0 to 50 pi0, particularly 0 to 480 qo is preferred.

The reaction pressure may be either increased or reduced pressure, but it is practical to carry out the reaction under normal pressure or slightly increased pressure. The apparent contact time (the apparent resting volume of the catalyst divided by the gas volume V supplied per unit time under reaction conditions) is carried out with a sand of 0.5 to 2.

The reaction can be carried out in a fixed bed or in a fluidized bed.

The reaction of the present invention has a smaller calorific value than the ammo-oxidation reaction of isobutene, so the reaction operation is easier.

Furthermore, since the combustion of ammonia is small, it is easy to implement industrially. With the catalyst of the present invention, the dehydration reaction appears to be very remote.

No unreacted tertiary butanol is found in the reaction product gas, and in most cases isobutene is found. The catalyst system of the present invention also shows relatively good performance in the ammoxidation reaction of isobutene, but the yield is generally lower than that of tertiary.
The invention using butanol is better.

EXAMPLES Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited only to these Examples.

Example 1 The experimental formula is MO. 2Bi6S wide Ni6P,K,. oNyu2
7066. ,(Si02),.

A fixed bed catalyst was prepared as follows. Silica sol (Si020% by weight, Na200.04% by weight)
715.4 liters and 3.9 liters of phosphoric acid (total amount 85% by weight) were added.

(1) 72.0 g of ammonium paramolybdate was dissolved in 300 g of pure water and added to (1).

(0) 59.3 ml of nickel nitrate was added to (0) and mixed. (m) 3.5 hours of potassium nitrate was added to (m).

(N) Nitric acid (6% by weight) 5 parts of pure water and 20 parts of pure water were mixed, and 99.0 parts of bismuth nitrate was added and dissolved. this(
N) was added. (V) Finally, antimony trioxide 29.8
Added evening.

This was heated to dryness while thoroughly mixing. After baking the dried mass for 20 hours and 40 hours, water was added to mix it up and formed into a cylindrical shape of 2 mm x 2 mm. After drying, this was baked for 60 days and 4 hours. Examples 2 and 4~
12 A fixed bed catalyst whose empirical formula is shown in Table 1 was prepared in the same manner as the catalyst of Example 1.

Note that nitrates were used as raw materials for both the Rb component and the Cs component. Table 1 Example 3 The experimental formula is Mo, 2Bi6Sb, oNi6P, K, . oN
too. 27074. , (SiQ)7.

A fluidized bed catalyst was prepared as follows. Silica sol (Si020% by weight, Na200.04% by weight) 13
．． 4 kg was taken and 73 kg of phosphoric acid (85% content) was added thereto.

(1) 1.35k9 ammonium paramolybdate was dissolved in pure water and added to (1).

(b) 1.11k9 of nickel nitrate was added to (0) and mixed.

(m) Potassium nitrate was added to (m).

(W) Nitric acid (3% by weight) 5k9 to bismuth nitrate 1.
85k9 was added and dissolved, and this was added to (W). (V)
0.93k9 of antimony trioxide was taken and mixed well with (V). This suspension is dried using a mist drying device.
It was then mist-dried using a conventional method. The generated microspherical powder is
It was fired at 00°C for 2 hours, at 400°C for 2 hours, and finally at 60°C and 04 hours. This fluidized catalyst had enough strength to withstand industrial use. Comparative Examples 1-3 The catalysts of Comparative Example 1 and Comparative Example 2 whose empirical formulas are shown in Table 2 were prepared in the same manner as the catalyst of Example 1 and the catalysts of Comparative Example 3
Each of the catalysts was prepared in the same manner as the catalyst of Example 3.

Note that ferric nitrate was used as a raw material for the Fe component. 2 Test Methods and Activity Test Results The activity tests of the catalysts in Examples and Comparative Examples were carried out by the following method.

Test A: The inner diameter of the catalyst was 16 ◇ so that each catalyst was in contact with the
into a U-shaped reactor.

This is heated with a molten salt solution consisting of a mixture of equal amounts of sodium nitrite and potassium nitrate and maintained at a predetermined reaction temperature. Inject the reaction gas into this reactor for 1 hour (NTP conversion)
supply at the rate of

Test B A fluidized bed reactor with a catalyst flow section having an inner diameter of 2 inches and a height of 2 inches is filled with catalyst.

A reaction gas is supplied into this reactor so that the apparent linear gas velocity is 15 skin/sec. Table 3 shows the catalyst activity test results using these test methods.

Note that the yield of methacrylonitrile and the contact time are defined as follows.

Methacrylonitrile yield (%) Carbon weight of synthesized tertiary butanol XI
OONote that the yields of acetonitrile, hydrocyanic acid, and isobutene are also calculated based on the same machine and carbon weight as the methacrylonitrile yield.

Contact time [sec]

Claims (1)

[Claims] 1. Tertiary butanol, together with oxygen and ammonia, molybdenum, bismuth, antimony and nickel, and at least one element selected from the group consisting of sodium, potassium, rubidium and cesium, or further with phosphorus. 1. A method for producing methacrnylonitrile, which comprises reacting at high temperature using an oxide composition containing the oxide composition as a catalyst. 2 The catalyst has the empirical formula MO_1_2Bi_aSb_bNi
_cP_dA_eO_f (A is Na, K, Rb
At least one element selected from the group consisting of ~15,
c=1-10, d=0-5, e=0.3-5 and f=
The number corresponds to the oxide formed by combining each of the above components. ) Claim 1 is an oxide composition represented by
The method for producing methacrylonitrile described in Section 1.