JPS5859934A - Preparation of methacrolein - Google Patents

Abstract

PURPOSE:To prepare the titled compound safely, in high yield, without using toxic substance, by using a mixture of tert-butyl alcohol and isobutylene as a raw material, and carrying out the vapor-phase catalytic oxidation reaction of the raw material in the presence of a specific catalyst. CONSTITUTION:Methacrolein is prepared by the vapor-phase oxidation of a mixture of tert-butyl alcohol and isobutylene with molecular oxygen or a molecular oxygen-containing gas in the presence of a catalyst having the composition of formula (A is Co or Co and Ni; L is P, As or B; Q is K, Rb or Cs; X is Ti, Sn, Pb, Mg, etc.; a, b, c, d, e, f, g, and h represent the numbers of A, Fe, Bi, L, Q, Mo, X and O atoms, respectively, and when f is 12, then a is 2-15, b is 0.5-7, c is 0.1-4, d is 0-4, e is 0.01-1.0, g is 0-3 and h is defined by the atomic valences of other elements).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves the production of methacrolein tl-, which has a general composition of AaFebBl, by oxidizing a mixture of tertiary-butyl alcohol and imbutylene in the gas phase with molecular oxygen or a molecular oxygen-containing gas. LdQoMofxgOh (in the formula, A represents cobalt or cobalt and nickel, L is phosphorus,
represents at least one element selected from arsenic and boron; Q represents at least one element selected from potassium, rubidium and cesium; %X represents titanium, tin,
Represents at least one element selected from lead, magnesium, chromium, zinc, manganese, and tungsten, and a
* b+ Qs 6+ ep f+ g and h
are each A.

Fe, Bi, L'! and the number of atoms of 0. If f is 12, a is 2 to 15.1) is 0.5
~7. C is 0.1-4. (l is O-4, e is o, o 1
-1. o and g take values from 0 to 3. h is a value naturally determined by the valences of other elements. ) The present invention relates to a method for producing methacrolein, which is characterized by using the catalyst shown in (1).

Many methods for producing methacrolein by gas phase catalytic oxidation reactions have been proposed. However, most of these methods use isobutylene as a starting material.

Tertiary-butyl alcohol c is hereinafter referred to as TEA. )
A method for obtaining methacrolein by gas phase oxidation using as a starting material is described in JP-A-48-32814.

However, this method uses thallium oxide as one of the catalyst components, and its main feature is that it contains thallium.

As is well known, thallium oxide may easily undergo reduction in a reducing atmosphere and become a lower-order oxide or metal thallium and volatilize.

Thallium is a toxic substance that can cause mental disorders when absorbed into the human body through inhalation, adhesion, etc., and the industrial use of such a substance as a catalyst component may pose an extremely serious problem. .

The present inventors have conducted extensive studies on catalyst systems that do not use such toxic substances, and have found that methacrolein can be produced in extremely high yield from a mixture of TEA and isobutylene when a catalyst having the above composition is used. They discovered what could be done and completed the present invention.

In the present invention, the reaction rate of TEA reaches 100%.

The catalyst used in the present invention can be produced, for example, as follows.

suitable molybdates, e.g. compounds of iron, bismuth, cobalt soluble in aqueous solutions of ammonium molybdate;
If necessary, nickel compounds, potassium (and/or rubidium, cesium) compounds, and if necessary,
At least one compound selected from phosphoric acid, arsenic acid, or boric acid, and if necessary, water-soluble titanium, tin, lead,
At least one compound selected from magnesium, chromium, zinc, manganese, and tungsten compounds is added in the form of an aqueous solution. The resulting slurry suspension is evaporated to dryness as it is or with the addition of a suitable carrier material, and then calcined in the presence of air or oxygen at a high temperature, e.g., 400 to 800 DEG C., for 4 hours or more.

As a starting material for molybdenum, in addition to ammonium molybdate, molybdic acid or molybdenum trioxide can be used. Examples of water-soluble iron, bismuth, cobalt, nickel, potassium, rubidium, and cesium compounds include nickel nitrate.

Cobalt nitrate, ferric nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, bismuth nitrate, etc. can be used.

Water-soluble titanium, tin, lead, magnesium, chromium,
Examples of L, Manga, No 1-Tung, and Stellar compounds include titanium chloride, titanium nitrate, titanium oxide, tin chloride, tin nitrate, lead nitrate, magnesium nitrate, magnesium carbonate, chromium nitrate, chromic anhydride, zinc nitrate, and nitric acid. Manganese, ammonium tungstate, etc. can be used.

As the carrier material, silica gel, silica sol, diatomaceous material, alumina, carporundum, etc. are used.

Catalysts are generally used as granules or tablets in fixed beds, but can also be used in moving or fluidized beds.

Air is usually used as molecular oxygen, but pure oxygen may also be used. Further, oxygen may be diluted with an inert gas such as nitrogen or carbon dioxide.

It is also preferred to use water vapor as a diluent.

The reaction of the present invention is usually carried out at a temperature of 250 to 450°C and under normal pressure to 10 atm.

In the present invention, for example, when air and steam are used, the contact time of the mixed raw material gas is 0.
It is 1 to 10 seconds.

The ratio of TEA, imbutylene, oxygen and water vapor contained in the mixed gas passed over the catalyst is 1 to 5 mol of oxygen and 1 mol of water vapor per 1 mol of total moles of TEA and imbutylene.
A proportion of ˜20 mol is suitable.

The present invention will be explained in more detail below with reference to Examples.

The reaction rate, selectivity, and single flow yield in Examples and Reference Examples shall comply with the following definitions.

Number of moles of supplied TBA or TBA and inphelene Number of moles of reacted TBA or TBA and inphelene Reference example 1 Ammonium paramolybdate 42.4F is dissolved in distilled water, nitric acid strength I70.28f is added and dissolved. While stirring this solution, an aqueous solution containing 40.2 f of cobalt nitrate, an aqueous solution containing 8.1 f of iron nitrate, and a dilute nitric acid solution containing 9.7 f of bismuth nitrate are added. 1.5.1 f of finely powdered silica gel is added to the resulting muddy suspension and evaporated to dryness with thorough stirring. The mixture is further heated at 300°C for 3 to 4 hours, cooled, and then pulverized.

The powder thus obtained is molded and then calcined at 650° C. for 4 hours or more under air circulation. This catalyst is expressed in atomic ratio as CO7F 81B 11K o, 1a M O12°
49.5. (The value for oxygen is omitted below as it is a value naturally determined by the valence of other elements.)
20 ml of this catalyst was packed into a reaction tube with an inner diameter of 18 mm, and a mixed gas consisting of 1 mol of TBA, 12.4 mol of air, and 10 mol of water vapor was charged into the reaction tube at a space velocity of 150 t-gas/
When the reaction was carried out at 330°C by feeding at t-cat/hr, the TEA reaction rate was 100%, the second methacrolein selectivity was 80.3%, and the methacrolein single flow yield was 80.3%. .

Reference Example 2 In Reference Example 1, cobal nitrate) 34.9f was substituted for copal nitrate) 40.2F, nickel nitrate 11.6F was substituted, rubidium nitrate 0.412 was substituted for potassium nitrate 0.282,
A catalyst was prepared in exactly the same manner as in Reference Example 1 except that fine powder silica gel 1541F was used in place of fine powder silica gel 13.1f to obtain a catalyst having the following composition.

C06N12FθI B11Rb0.14 M012 When the reaction was carried out under the same conditions as in Reference Example 1, the reaction rate of TEA was 100%, the selectivity of methacrolein was 82.1%, and the single flow yield of methacrolein was 8
It was 2.1%.

Reference Example 3 A catalyst prepared in the same manner as in Reference Example 2 except that cesium nitrate was used in place of rubidium nitrate 0.419 in Reference Example 2 (catalyst composition: Co6Ni2Fe, Bi).

Cs. ,,a MO12) was used to carry out the reaction under the same reaction conditions as in Reference Example 1.

The reaction results were as follows: TDA reaction rate was 100%, methacrolein selectivity was 80.5%, and single flow yield was 80.5%.

Reference Examples 4 to 14 Using catalysts prepared according to Reference Example 1 and having the compositions shown in Table 1, reactions were carried out under the same reaction conditions as in Reference Example 1.

The results are shown in Table-1.

The reaction rate of the mixture of and isobutylene was 98.0%, the selectivity of methacrolein was 1%, and the single flow yield of methacrolein was 79.5%.

Examples 2 to 14 Reactions were carried out in the same manner as in Example 1 using the catalysts used in Reference Examples 2 to 14 and a mixture of TBA and isobutylene in the mixing ratio shown in Table 2. The results are shown in Table-2.

Claims (1)

[Claims] When methacrolein is produced by oxidizing a mixture of tertiary butyl alcohol and imbutylene in the gas phase with molecular oxygen or a molecular oxygen-containing gas, the general composition is AaFebBl. LdQoMOfXgOhc In the formula, A represents cobalt or cobalt and nickel, L is phosphorus,
represents at least one element selected from arsenic and boron; Q represents at least one element selected from potassium, rubidium, and cesium; X represents titanium, tin,
Represents at least one element selected from lead, magnesium, chromium, zinc, manganese, and tungsten, a,
b, c, d, e, f, g and h are each A. If Of, which indicates the number of atoms of IFe, Bi, L, C1, Mo, X, and 0, is 12, a is 2 to 15
．． b is 0.5-7°C is 0.1-4. (i is O-4, e
is 0.01-1.0. g takes a value of 0 to 3. h is a value naturally determined by the valences of other elements. ) A method for producing methacrolein, characterized by using the catalyst shown in (a).