JPS6133135A - Preparation of methacrolein and methacrylic acid - Google Patents

Abstract

PURPOSE:To obtain advantageously the titled compound, by using a specific catalyst consisting essentially of phosphorus, molybdenum and an alkali metal, etc. and oxygen in catalytically oxidizing isobutyl alcohol in the vapor phase with molecular oxygen. CONSTITUTION:Isobutyl alcohol is catalytically oxidized in the vapor phase with molecular oxygen in the presence of a catalyst expressed by the formula (X is alkali metal or/and Tl; Z is Zn, Al, Sb, S, In, U, Cd, Ca, Ag, Cr, Si, Ge, Co, Zr, Sn, Sr, Se, W, Ta, Ti, Fe, Te, Cu, Th, Pb, Nb, Ni, V, Ba, Bi, As, Be, B, Mg, Mn, Sm, La, Rh, Ru, Re, Pt or/and Pd; a-e are the atomic ratios of the respective elements; a is 0.01-8; c is 0.01-5; d is 0-20 when b is 12; e is the number of oxygen atoms required to satisfy the valence of the above-mentioned respective components) to keep the reaction system at a low temperature and obtain advantageously the titled compound in sufficient selectivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a method for producing methacrolein and methacrylic acid by subjecting isobutyl alcohol to gas phase catalytic oxidation using molecular oxygen.

[Conventional technology]

Conventionally, many proposals have been made regarding methods for producing methacrolein and methacrylic acid by gas-phase catalytic oxidation or gas-phase catalytic oxidative dehydrogenation using inbutylene, t-butyl alcohol, isobutyraldehyde, or isobutyric acid as a starting material.

However, there is still no known method for producing F. methacrolein and methacrylic acid using a vapor phase catalytic oxidation method starting from isobutyl alcohol.

[Problem that the invention seeks to solve]

The present inventors have previously invented a method for producing methacrolein and methacrylic acid by phase catalytic oxidation of isobutyl alcohol, but the selectivity is low, and it is desired to develop a further improved catalyst. There are n. The object of the present invention is to provide a catalyst which advantageously produces methacrolein and methacrylic acid while keeping the reaction temperature low.

[Means to solve the problem]

In the present invention, in producing methacrolein and methacrylic acid by vapor phase catalytic oxidation of butyl alcohol with molecular oxygen, the general formula % formula % (wherein, P, Mo and 0 are respectively n phosphorus, molybdenum and acid 511; kermanium, cobalt, zirconium,
Tin, strontium, selenium, tungsten, tantalum, titanium, iron, tellurium, copper, )IJium.

At least one element selected from the group consisting of lead, niobium, nickel, vanadium, barium, bismuth, arsenic, beryllium, borium, magnesium, manganese, samarium, lanthanum, rhodium, ruthenium, rhenium, platinum, and palladium shows.

However, a-, b, c, d, and 8 represent the atomic force of each element, and when b = 12, a = 0.01 to 8, c
= (L01~5, eL = 0~20,
e is the number of oxygen atoms necessary to titrate the valence of each of the above components. ) is a method for producing methacrolein and methacrylic acid, characterized in that it uses a catalyst represented by n.

In producing the catalyst used in the present invention, each element used as a catalyst raw material can be an oxide or an oxide that becomes an oxide when ignited.

In preparing the catalyst, any conventionally known method such as evaporation to dryness or precipitation can be used.

A carrier can be used in preparing the catalyst. As the carrier, rt, silica, alumina, silica-alumina, etc. are used.

When using the catalyst in the total gas phase catalytic oxidation according to the present invention, it is preferable to use isobutyl alcohol, which is a raw material, after diluting it with an inert gas.

Although pure oxygen gas or air can be used as the oxygen source for oxidation, air is industrially advantageous.

The oxygen concentration in the feed gas when carrying out the reaction can vary within a wide range, but is preferably between 5 and 20 volumes;
When the oxygen concentration is low, methacrolein is preferentially obtained, and when it is high, methacrylic acid is preferentially obtained.

The reaction pressure used ranges from normal pressure to several atmospheres.

The reaction temperature can vary within the range of 150-450°C. The reaction can be carried out in either a fluidized bed or a fixed bed.

〔Example〕

Hereinafter, a method for producing ilB of the catalyst according to the present invention and a reaction example using n+ will be specifically explained.

In the examples, the reaction rate of isobutyl alcohol and the selectivity of methacrolein and methacrylic acid produced are defined as follows.

Reaction rate of isobutyl alcohol (%) Number of moles of isobutyl alcohol supplied Selectivity of methacrolein (a) Number of moles of reacted isobutyl alcohol Selectivity of methacrylic brewing (b) Number of moles of methacrylic acid produced Examples and comparisons below Parts in the examples are parts by weight, and analysis was performed using gas chromatography.

Example 1 200 parts of ammonium molybdate was added to 1000 parts of water, and the mixture was heated and stirred. Next, 9 parts of 1[L of 85% phosphoric acid were added, and further 9.5 parts of potassium nitrate were added, and while stirring, the mixture was heated to evaporate to dryness, and then kept at 130° C. for 16 hours to dry.

After the obtained solid was completely finely pulverized, it was compressed into a bottom mold.
It was calcined at a°C for 4 hours to obtain a catalyst. The composition of elements other than oxygen and the carrier (the same applies hereinafter) of the obtained catalyst was PI Mo12
It was K1.

This catalyst was packed into a fixed bed reactor and maintained at 340°C.
A mixed gas with a composition of 5% isobutyl alcohol, 10% oxygen, 20% water vapor, and 65% nitrogen by volume total space velocity 240
The reaction was carried out at 0 hr"-'.

As a result, the reaction rate of isobutyl alcohol was 100%, the selectivity of methacrolein was 3.58%, and the selectivity of methacrylic acid was 1%.
It was 3%.

Example 2 200 parts of ammonium molybdate and 12 parts of gold ammonium metavanadate were added to 1000 parts of water and heated and stirred.

Next, 11.9 parts of 85% phosphoric acid were added, and 1α4 parts of potassium nitrate were further added, heated with stirring to evaporate to dryness, and further dried at 150° C. for 16 hours.

Obtained: rL7'C After the solid material was completely pulverized, it was compression molded.
ii It was calcined at 380° C. for 4 hours and used as a catalyst. The composition of the catalyst f' obtained was PHMo1l VIKB.

When the reaction was carried out under the same conditions as in Example 1, the reaction rate of isobutyl alcohol was 100%, the selectivity of methacrolein was 341%, and the selectivity of methacrylic acid was z.
It was 5%.

Example 3 200 parts of ammonium molybdate and 8 parts of ammonium metavanadate were added to 1000 parts of water and heated and stirred.

Next, 16.3 parts of 85% phosphoric acid and 1.8 parts of boric acid were added, followed by 91 parts of nitric acid steel. A solution dissolved in 30 parts of water was mixed, 5.5 parts of cesium nitrate was added, and the mixture was heated with stirring to evaporate to dryness, and further dried at 150° C. for 16 hours. After finely pulverizing the obtained isomorphic gold, compression molding is performed,
This f'L was calcined at 380°C for 4 hours to form a catalyst and L7m. Composition of the obtained nyt catalyst Fl Pl, s M 012 %80
It was u64E&308α3.

When the reaction was carried out under the same conditions as in Example 1, the reaction rate of isobutyl alcohol was 100%, the selectivity of methacrolein was 35.3%, and the selectivity of methacrylic acid was &6%.

Examples 4 to 25 Reaction results when isobutyl alcohol was reacted in the same manner as in Example 1 using the catalyst shown in Table 1 prepared according to Example 3 with one change in catalyst component vi. - As shown in the table.

Example 26 Using the catalyst prepared in Example 25, this catalyst was packed into a fixed bed reactor and maintained at 340°C.

A mixed gas with a composition of 4% isobutyl alcohol, 214% acid, 25% water vapor, and 57% nitrogen by volume is heated at a space velocity of 220%.
The reaction was carried out at 0 hr-''. As a result, the selectivity of isobutyl alcohol was 1a6%, the selectivity of methacrolein was 1a6%, and the selectivity of methacrylic acid was 32.1%.

Example 27 Using the catalyst prepared in Example 25, this catalyst was packed into a fixed bed reactor, maintained at 340°C, and containing 4% isobutyl alcohol, 814% acid, 25% steam, and 57% nitrogen by volume.
A mixed gas of gold having a composition of was introduced at a space velocity of 1100 hr-1 and reacted. As a result, the reaction rate for inbutyl alcohol was over 100, the selectivity for methacrolein was 55%, and the selectivity for methacrylic acid was 31.0%.

Comparative Example 1 A total catalyst was prepared in the same manner as in Example 1 except that potassium nitrate was omitted. Obtained: n, yt The composition of the catalyst was PI Mo12.

When the reaction was carried out under the same conditions as those in Example 1, the reaction ratio of isobutyl alcohol was 4100%, the selectivity of methacrolein was 21.2%, and the selectivity of methacrylic acid was 4.5%.

Comparative Example 2 The entire catalyst was prepared in Example 3 except for ammonium molybdate. That is, 200 parts of ammonium metavanadate is added to 1000 parts of water, and the mixture is heated and stirred. Next, 369.6 parts of 85% phosphoric acid and 39.6 parts of boric acid are added, and then a solution of 206.5 parts of copper nitrate dissolved in 1000 parts of water is added, followed by 125 parts of cesium nitrate. While stirring, this mixture @*' was heated to evaporate to dryness, and further heated to 130°C for 16
Let dry for an hour. The subsequent operations followed Example 11C.

The set of n7c catalysts obtained is Pl, li vo, s Ou6
It was 4k30 sas.

The reaction was carried out under the same conditions as in Example 1 except that the total reaction temperature was 560°C under the reaction conditions in Example 1. The results were as follows: 98% of isobutyl alcohol anti-V5, 9.1% of methacrolein selectivity, and 9.1% of methacrolein selectivity. The acid selectivity was 2.8%.

Comparative example 3 A catalyst was prepared in Example 3 except for the phosphoric acid.

The composition of the obtained refined catalyst was Mo12Vα8Cuα4B (kl
It was pot 3.

What is the reaction temperature under the reaction conditions in Example 1? When the reaction was carried out under the same conditions as in Example 1 except that the temperature was 360°C, the reaction rate of isobutyl alcohol was 100 yen, the selectivity of methacrolein was 9% per step, and the selectivity of methacrylic acid was 5.1%. .

Comparative Example 4 A catalyst was prepared in Example 5 except that ammonium molybdate and hyric acid were removed.

That is, 200 parts of ammonium metavanadate is added to 1000 parts of water, and the mixture is heated and stirred. Next, 39.6 parts of boric acid is added, and a solution of 20 and 5 parts of copper nitrate dissolved in 1000 parts of water is mixed together, and 125 parts of cesium nitrate is added. This mixed solution was heated while stirring to evaporate to dryness, and further 13
It was dried at 0°C for 16 hours. The subsequent operations were in accordance with Example 1.

The composition of the obtained catalyst was Vα8011α4Bα5cso,
It was 3.

When the reaction was carried out under the same conditions as in Example 1 except that the reaction temperature was 360°C under the reaction conditions in Example 11C,
The reaction rate for isobutyl alcohol was 100%, the selectivity for methacrolein was 45%, and the selectivity for methacrylic acid was 1.2%.

Claims (1)

[Claims] In producing methacrolein and methacrylic acid by vapor phase catalytic oxidation of isobutyl alcohol with molecular oxygen, the general formula P_aMo_bX_cZ_dO_e (where P, Mo and O represent phosphorus, molybdenum and oxygen, respectively) is used. , X represents at least one element selected from the group consisting of alkali metals and thallium,
Z is zinc, aluminum, antimony, sulfur, indium, uranium, cadmium, calcium, silver, chromium,
Silica, germanium, cobalt, zirconium, tin, strontium, selenium, tungsten, tantalum,
Titanium, iron, tellurium, copper, thorium, lead, niobium, nickel, vanadium, barium, bismuth, arsenic, beryllium, boron, magnesium, manganese, samarium,
Indicates at least one element selected from the group consisting of lanthanum, rhodium, ruthenium, rhenium, platinum, and palladium. Moreover, a, b, c, d and e represent the atomic ratio of each element, and when b=12, a=0.01 to 8,
c=0.01-5, d=0-20, and e is the number of oxygen atoms necessary to satisfy the valences of each component. )
A method for producing methacrolein and methacrylic acid, characterized by using a catalyst represented by: