JPH045245A - Production of p-xylene - Google Patents

Abstract

PURPOSE:To obtain p-xylene at a low cost by the oxidative dehydrogenation cyclization of isobutylene with O2 in the presence of a catalyst produced by adding B, P, S, Ti, etc., to an Mo-Bi-Fe system and supporting the obtained-O- containing composition on a carrier consisting of a silica-alumina and/or zeolite. CONSTITUTION:p-Xylene can be produced at a low cost by the oxidative dehydrogenation cyclization of isobutylene with molecular oxygen in the presence of a catalyst having a composition of formula (X is one or more elements selected from B, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, etc.; a to e are atomic ratio of each element and, when a=1, b=0.01-5, c=0.1-10, d=0-10 and e corresponds to the atomic valence of the above each component) and supported on a carrier consisting of a silica-alumina and/or a zeolite.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing paraxylene by oxidative dehydrocyclization of isobutylene.

[Conventional technology]

In recent years, the effective use of C4 fraction produced in the petrochemical industry has been actively carried out. Among them, several methods have been proposed for obtaining paraxylene using isobutylene as a raw material. For example, a method for producing paraxylene from isobutylene in the presence of a catalyst consisting of vanadium pentoxide and magnesium oxide (Japanese Unexamined Patent Publication No. 124035/1982).
, a method of oxidizing and dehydrocyclizing isobutylene in the presence of a catalyst consisting of a composite oxide of bismuth and cerium (Japanese Unexamined Patent Publication No. 53-2424) has been reported. However, these methods all have low yields of the target paraxylene, and are not industrially advantageous methods.

[Problem to be solved by the invention]

An object of the present invention is to provide a method for advantageously producing paraxylene by aqueous dehydrogenation of isobutylene.

[Means to solve the problem]

The present invention is based on the general formula % (where MO, Bi, Fe and O are respectively molybdenum, bismuth, iron and oxygen, or boron, phosphorus, sulfur,
At least one element selected from the elements consisting of titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, gallium, arsenic, tin, antimony, tellurium and cerium, a, b, c, (l and e
indicates the atomic ratio of each element, and when a = 1, b = α0
1 to 5, c=11.1 to 10, d=O to 10, and e
is the number of oxygen atoms necessary to satisfy the above-mentioned number of atoms of each component (4i), and in the presence of a catalyst using silica-alumina and/or zeolite as a carrier This is a method for producing para-xylene, which is characterized by catalytically reacting butylene with molecular oxygen.

The raw materials for the elements that are the catalyst components used in the preparation of the catalyst used in the button of the present invention are not particularly limited;
Oxides or hydroxides, chlorides, sulfates, and nitrates that can become oxides by ignition! ! Carbonates, ammonium salts or mixtures thereof are used.

In preparing the catalyst, known methods such as evaporation to dryness method, precipitation method, oxide mixing method, etc. can be used.

The catalyst component is used by being supported on a carrier. Silica-alumina and/or zeolite are used as carriers. Supporting method Fi is not particularly limited, but impregnation method, equilibrium adsorption method,
Known methods such as crosstalk method and coprecipitation method can be used.

At this time, the supporting ratio is based on 100 parts by weight of the catalyst component.
25 to 2000 parts by weight of carrier (preferably 50 to 100 parts by weight)
0 parts by weight).

When producing paraxylene using the catalyst of the present invention, molecular oxygen is added to isobutylene as a raw material, and an oxidative dehydrogenation reaction is performed in the presence of the catalyst.

The molar ratio of isobutylene to oxygen is preferably 1:α05-3. It is preferable to use the raw material gas after diluting it with an inert gas. Moreover, unreacted isobutylene can be recovered and used again. The molecular oxygen used for oxidation may be pure oxygen gas or air, but air is industrially advantageous.

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

The reaction temperature is preferably in the range of 300 to 700°C.

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

〔Effect of the invention〕

According to the method of the present invention, paraxylene can be advantageously obtained from isobutylene.

〔Example〕

In the Examples and Comparative Examples below, parts mean parts by weight, and the results were determined by analytical bagasse chromatography. Further, the reaction rate of isobutylene, mixed xylene selectivity, and disparate xylene selectivity are defined as follows.

Further, the contact time (W/F) was determined as follows.

Catalyst amount W (?) Contact time (W/F) = gas flow rate F (rnoL/kx) Example 1 50 parts of ammonium molybdate was added to 200 m of water and stirred with heating (Liquid A). Separately, add 60 parts of nitric acid and 5 parts of nitric acid to 200 parts of water.
After adding 0 parts and making it uniform, 41.2 parts of bismuth nitrate, 1050 parts of ferric nitrate, and 82.4 parts of nickel nitrate were added and dissolved (CB solution).

After adding Solution B to Solution A to form a slurry, 100 parts of pellet-shaped silica-alumina was added and evaporated to dryness while stirring with heating.

The obtained solid product was dried at 120°C, and then heat-treated at 600°C for 4 hours, and the book was used as a catalyst.

Composition of elements other than oxygen of the obtained catalyst (the same applies hereinafter) and carrier, M Of B 163 F e6. g Ni,
/s i 02-kL, O, this catalyst was packed into a reactor, and a mixed gas of 54% isobutylene, 2.54% oxygen, 10% water vapor, and 82.54% nitrogen (volume) was heated to a reaction temperature of 50%.
The reaction was carried out at 0° C. and a contact time of 24 (g·h/mot). When all the products were collected and analyzed by gas chromatography,
The reaction rate for isobutylene is 57.24, the selectivity for mixed xylenes is 1 & 7 excellent, the selectivity for para-xylene is 14.44, and other products include methacrolein, methacrylic acid, acetone, acetic acid, isobutane, co, co, toluene and ethylbenzene. etc. were obtained.

Example 2 A reaction was carried out under the same reaction conditions as in Example 1, except that the catalyst of Example 1 was used and the reaction temperature was 400°C. As a result, the y-response of isobutylene was 59.0%, the selectivity of mixed xylene was 27.24, and the selectivity of para-xylene was iK2[lo*.

Example 3 Using the catalyst of Example 1, the contact time was 12 (t-h/mo
The reaction was carried out under the same reaction conditions as in Example 1, except that the reaction conditions were as follows. As a result, the reaction rate of inbutylene was 4[11qb
The selectivity for mixed xylene was 2.52 scratches, and the selectivity for para-xylene was 1a84.

Example 4 A catalyst having a composition of Mol B161 Fel was prepared according to Example IK. This catalyst was supported on a silica-alumina carrier at a loading rate of 60 arc. At this time, the support * (the same applies hereinafter) is defined as follows.

Weight of heat-treated catalyst component + weight of carrier Using this catalyst, contact time was 30 (t-h/mot)
The reaction was carried out under the same reaction conditions as in Example 1, except for the following. As a result, the reaction rate of inbutylene was 54.9%, the selectivity of mixed xylene was 1&2qk, and the selectivity of para-xylene was 14.
．． It was 04.

Example 5 According to Example 1, MOL Bi (LI Fel pHJ
A catalyst having a composition of V was prepared. This catalyst was supported at a support ratio of 404 using a 1=1 mixture of silica-alumina and H-type mordenite as a support. Using this catalyst, a reaction was carried out under the same reaction conditions as in Example 4. As a result, the reaction of isobutylene was $6t4, the selectivity of mixed xylene was 14.311%, and the selectivity of para-xylene was 119%.

Examples 6-8 Catalysts shown in Table 1 were prepared according to Example 1.

Table 1 A reaction was carried out under the same reaction conditions as in Example 4 using these catalysts. The results are shown in Table 2.

Table 2 Comparative Example 1 A catalyst identical to Example 4 was prepared except that the silica-alumina carrier was omitted. A reaction was carried out using this catalyst under the same reaction conditions as in Example 4. As a result, the reaction rate of isobutylene was 2&54, the selectivity of mixed xylene was t94, and the selectivity of para-xylene was 4.34.

Reactions were carried out under various reaction conditions. As a result, the reaction rate of isobutylene was 4α24, the selective superposition of mixed xylene was 1, and the selectivity of para-xylene was 4.34.

Claims (1)

[Claims] General formula MO_aBi_bFe_cX_dO_e (wherein MO, Bi, Fe and O are molybdenum, bismuth, iron and oxygen, respectively, X is boron, phosphorus, sulfur,
At least one element selected from the elements consisting of titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, gallium, arsenic, tin, antimony, tellurium and cerium, a, b, c, d and e are Indicates the atomic ratio of each element, when a = 1, b = 0.01 to 5, c = 0
．． 1 to 10, d = 0 to 10, and e is the number of oxygen atoms necessary to satisfy the valence of each of the above components), and the carrier is silica-alumina and/or Alternatively, a method for producing baraxylene, which comprises catalytically reacting isobutylene with molecular oxygen in the presence of a catalyst using zeolite.