JPH02304033A - Hydrogenation dealkylation process - Google Patents

Abstract

PURPOSE:To obtain the objective substance in high yield and selectivity by using a catalyst composed of vanadium supported on alumina particles and contacting the catalyst with an alkylaromatic compound or a stock oil containing the compound in the presence of hydrogen. CONSTITUTION:An aromatic compound having high utility value can be produced by contacting (A) an alkylaromatic compound or a stock oil containing the compound with (B) a catalyst composed of alumina carrier and 0.1 to 30wt.% of vanadium in the presence of hydrogen at 450 to 680 deg.C (preferably 500 to 650 deg.C) under a hydrogen partial pressure of 2 to 30kg/cm<2>, thereby effecting hydrogenation dealkylation reaction of the starting compound. Vanadium is present in the catalyst in the form of an oxide such as V2O3 or V2O4 and forms a catalyst particle having a weight-average particle diameter of 25 to 250mum, a bulk density of 0.3 to 1.5g/cm<3> and a pore volume of 0.1 to 1.5m<3>/g by using gamma-alumina, etc., as a carrier. Preferably, the hydrogenation dealkylation process and the regeneration of the catalyst are alternately performed by using a pair of fluidized bed columns.

Description

[Detailed Description of the Invention] [Background of the Invention] Technical Field Heretofore, thermal methods and catalytic methods have been used to produce aromatic compounds with high utility value by alkyl hydrogenation of alkyl aromatic compounds. method is being carried out.

Thermal methods require harsh reaction conditions at high temperatures of 700°C or higher and high pressure, which requires the use of expensive heat-resistant abrasives and complicated equipment to prevent the temperature inside the reactor from rising due to reaction heat. Requires structure and manipulation.

In the catalytic method, the reaction can be carried out at a temperature lower than 700°C using a catalyst, but as far as the inventors know, conventional methods have various problems as described below. be.

A method using a catalyst in which chromium oxide, molybdenum oxide, or the like is supported on alumina or the like is industrially implemented as a membrane alkyl hydrogenation method such as toluene. However, the activity of these catalysts is not sufficient, and when the reaction temperature and hydrogen pressure are increased to obtain a high conversion rate, side reactions such as hydrogenolysis of aromatic rings increase.

Additionally, a method using a catalyst in which a transition metal component such as Rh5Pt or Ir is supported on alumina or the like is known, but these metal components are expensive and uneconomical, and their activity is unstable. . Further, there are also problems in that poisoning due to sulfur contained in the feedstock oil and deactivation due to coke precipitation are significant.

On the other hand, methods using solid acid catalysts such as silica, alumina, and zeolite are known, but their activity is not sufficient and they also have the disadvantage of causing many side reactions such as disproportionation of alkyl aromatic compounds and formation of coke. .

Alumina is also a known catalyst for hydrogenation membrane alkylation, but although the selectivity of the hydrogenation membrane alkyl reaction is high, the activity is not sufficiently high.

[Summary of the invention]

Summary> The present inventors have discovered that the problems of these conventional methods can be overcome.
As a result of research on the excellent hydrogenation membrane alkyl method,
We have discovered catalyst particles with excellent activity, selectivity, and economy.

That is, the membrane alkyl hydrogenation method for alkyl aromatic compounds according to the present invention is a method for hydrogenating alkyl aromatic compounds using a catalyst made of vanadium supported on alumina particles (vanadium content in terms of metal vanadium is 30% or less). Aromatic compounds or raw oil containing them in the presence of hydrogen 450 ~
It is characterized by dealkylation by contacting at 680°C.

Effect> According to the method of the present invention, in the hydrogenation film alkyl reaction of an alkyl aromatic compound or a raw material containing the same, the target aromatic compound or lower alkyl aromatic compound is heated under relatively mild conditions. It can be produced with high yield and high selectivity.

= 3- Furthermore, a major feature of the method of the present invention is that the method uses inferior-quality materials that contain large amounts of substances that poison the catalyst or that tend to cause process troubles such as coking when performing membrane alkyl hydrogenation. It became possible to process raw materials.

In other words, in the conventionally known hydrogenation membrane alkyl method,
Relatively high-purity alkyl aromatic compounds, such as toluene fraction extracted from reformed naphtha, are mainly used as feedstock oil, and they usually contain sulfur and nitrogen compounds, which are catalyst poisons, and impurities, which are the main cause of coke formation. Oils that contain large amounts of saturated hydrocarbons, such as dienes, olefins, and high-boiling polycyclic aromatic compounds, are either not used as feedstocks because they are unsuitable, or they are not used after the above substances have been removed at great cost in refining. It was either used or.

However, according to the method of the present invention, this problem has been solved in two ways. First, the catalyst used in the method of the present invention can exhibit high activity and selectivity even when raw material containing a large amount of the above-mentioned substances is used. Second, by using a reactor preferably consisting of a two-column fluidized bed, the catalyst can be continuously regenerated, making it possible to treat raw oils that produce a large amount of coke, and also achieving high catalyst activity and selectivity. properties can be maintained constant and continuous.

[Detailed description of the invention]

Catalyst> The catalyst used in the method of the present invention consists of vanadium and an alumina carrier. The content of vanadium as a metal is 0.0% in the catalyst particles. It is 1 to 30% by weight. When the vanadium content is less than 0.1% by weight, the activity of the catalyst is insufficient. If the amount exceeds 30% by weight, not only will the catalyst become expensive and uneconomical, but the pore structure of the carrier will be clogged with vanadium, resulting in insufficient activity, and especially when a fluidized bed is used, the catalyst particles will be The bulk specific gravity becomes too large, resulting in poor flow, which is undesirable.

Vanadium is usually an oxide such as V203 or V2O4
takes the form of The II3 form of V205 may be used, but it is not so preferred from the viewpoint of heat resistance of the catalyst particles. However, since the reaction is carried out under hydrogen pressure, even if it is initially in the form of V2O5, it is immediately reduced to a state with a low oxidation number under reaction condition F. Vanadium may also be in the form of its sulfides, salts or organic compounds.

The alumina support is preferably porous alumina, such as γ-alumina.

The catalyst particles preferably have a pore volume of 0.1 to 1.
5 crl/g, more preferably 0.2 to 1.2 cd
/g, later on. In addition, when a fluidized bed is used as the reaction device, in order to obtain good fluidity, the weight average diameter of the catalyst particles is 25 to 2507 zm, preferably 40 to 2507 zm.
120 μm, and the bulk density is 0. 3-1. ! 5g
/cd, preferably 0.4 to 1.3g/cd,
Preferably, it is substantially spherical.

In addition to vanadium, the catalyst used in the method of the present invention also includes Nt, Mo, and Pts Rhs Re.

Cr, Ca, etc. may be included in the form of a metal or oxide.

In addition, the alumina carrier is mainly composed of alumina, but in addition to alumina, in order to increase the thermal stability of the particles,
It may contain silica, titania, magnesia, oxides such as Ba5La, P, and the like.

The catalyst used in the method of the present invention can be prepared by supporting vanadium on an alumina carrier by a conventional method such as an impregnation method or a dipping method. For example, impregnation or immersion is performed with a solution of an inorganic salt such as (2) such as ammonium metavanadate, such as an oxalic acid aqueous solution, or an organic solution of (2) such as an organic compound such as acetylacetonate vanadium such as a toluene solution, followed by drying, thermal decomposition, hydrogen reduction, etc. It can be prepared by subjecting it to the following treatment.

Alternatively, vanadium may be supported by impregnating an alumina carrier with an oil containing vanadium, such as crude oil, atmospheric residual oil, vacuum residual oil, pitch, etc., and then thermally decomposing the oil.

In addition, there are also combinations of these, such as:
A mixed solution of acetylacetone vanadium in toluene, etc. and vacuum machine oil, etc. is thermally decomposed on alumina particles using, for example, a fluidized bed, and preferably all or part of the precipitated coke is decomposed using a molecular oxygen-containing gas (and/or) steam, etc. can be combusted or gasified to produce the catalyst used in the method of the invention.

In the method for internal hydrogenation of alkyl groups, an alkyl aromatic compound or a raw material oil containing the same is heated to 450 to 60% hydrogen in the presence of hydrogen using the above catalyst.
Hydrogenation film alkyl is carried out at 80°C, preferably 500-650°C. The hydrogen partial pressure is usually 1 to 100 kg/(!J, preferably 1 to 50 kg/at, more preferably 2 to 3
0 kg/cm3.

Alkyl aromatic compounds are, for example, monocyclic or polycyclic aromatic compounds substituted with one or more alkyl groups, such as toluene, xylene, trimethylbenzene, indene, methylnaphthalene, dimethylnaphthalene, trimethylnaphthalene. , acenaphthene, etc. Feedstock oils containing alkyl aromatic compounds include, for example, catalytic cracking recycled oil, catalytic reforming oil, naphza cracking byproduct oil, coal tar, coal liquefied oil, and the like. These raw materials may include sulfur compounds such as thiophene and benzothiophene, nitrogen compounds such as pyridine and quinoline, and oxygen compounds such as phenol, benzofuran, dibenzofuran and the like.

In the method of the present invention, aromatic compounds such as benzene and naphthalene, as well as lower alkyl aromatic compounds having a smaller number of carbon atoms in the alkyl group than the raw materials, such as methylnaphthalene, can be produced from these raw materials in high yield by hydrogenation membrane alkyl reaction. It can be produced with high selectivity and high selectivity. In other words, the method of the present invention achieves a high yield under relatively mild reaction conditions, that is, relatively low temperature and low hydrogen pressure, due to the high activity of the catalyst used, and eliminates side reactions such as hydrogenolysis of aromatic rings and coke. It suppresses formation and disproportionation, has a high selectivity, and is resistant to catalyst poisoning due to impurities in the raw material and coke precipitation, so it can process a variety of feedstock oils, has high reactivity, and is economical. , exhibits many outstanding advantages.

As a preferred embodiment of the present invention, a two-column flow! One fluidized bed performs membrane alkyl hydrogenation of alkyl aromatics or feedstock oil containing them, and the other fluidized bed regenerates the catalyst with coke attached, and the catalyst particles between the two columns are Do a cycle. By this method, the method of the present invention can be carried out continuously, and in particular, it is possible to carry out effectively the hydrogenation membrane alkyl of poor quality feedstock oil which produces a lot of coke.

Regeneration of the catalyst is preferably carried out using an oxygen-containing gas such as oxygen,
Completely or partially gasifying and removing the coke on the catalyst with a gas such as air and/or steam containing one or more of CO2, hydrocarbons or hydrogen, preferably at a temperature of 600 to 1000'C. Consisting of

Example 1 Alumina particles (pore volume 0.96cnl/g, specific surface area 240i/g, weight average diameter 70μIn, bulk density 0.4
5 g/cni, substantially spherical) using 4 liters,
Vanadium was supported in the next step.

80 g of oxalic acid are dissolved in 1520 g of water, and then 39 g of ammonium metavanadate are dissolved in this solution.

This solution is impregnated into the pores of the above alumina particles,
Dry in air at 05°C for 1115 minutes. These particles were packed into a fluidized bed reactor with an inner diameter of 8 cm, and treated at 250°C for 1 hour while passing air to thermally decompose ammonium metavanadate, and then heated at 450°C for 3 hours for 60
Reduction treatment is performed with hydrogen at 0° C. for 1 hour. As a result, a catalyst containing 0.9% by weight of vanadium as a metal was obtained.

Catalysts containing 0.3% by weight, 7.8% by weight and 25.8% by weight of vanadium as metal were prepared by a similar method. Using these catalysts and alumina particles not carrying vanadium, a hydrogenation membrane alkyl reaction of β-methylnaphthalene was carried out in the fluidized bed reactor described above. The reaction conditions were a temperature of 600° C., a hydrogen partial pressure of 7.8 kg/cm, a contact time of about 8 seconds, and a raw material supply rate of about 1.2 kg/h. The reaction results are shown in Table 1. By the method of the present invention, membrane alkyl hydrogenation could be carried out in high yield and high selectivity.

A catalyst containing 38% by weight of vanadium was similarly prepared and a similar reaction experiment was conducted, but the fluidity was not good and the reaction results were as follows: naphthalene yield: 25.9 mol%, naphthalene selectivity: 91.7. It was mol%.

Example 2 A catalyst with a vanadium content of 7.3% by weight obtained in the same manner as in Example 1 and nickel, which is already known to have hydrogenation membrane alkyl activity, were added to the alumina support used in Example 1. A membrane alkyl hydrogenation experiment of β-methylnaphthalene was conducted using the same apparatus as in Example 1 using a catalyst supported at 7.2% by weight.

The reaction conditions were a temperature of 600°C and a hydrogen partial pressure of 8. 0kg/
ctl, contact time approximately 8 seconds, raw material supply rate approximately 1.2 kg
/h.

The reaction results are shown in Table 2. By the method of the present invention, membrane alkyl hydrogenation could be carried out with high yield and selectivity.

-12= Example 3 A fluidized bed regenerator having an inner diameter of 2.8 am was connected to the same fluidized bed reactor as in Example 1, so that catalyst particles were circulated between both fluidized beds.

As a catalyst, 4.5 liters of catalyst particles having a vanadium content of 2.8% by weight, prepared in the same manner as in Example 1, were used.

The reactor contains about 2.4 NTIl/h of hydrogen and about 1.0 NTIl/h of catalytic cracking circulating oil as a feedstock. ．． 2kg/h, 60
0°C, hydrogen partial pressure7. Membrane alkyl hydride was carried out at a pressure of 5 kg/cm and a contact time of about 15 seconds. The regenerator contains 0.55N'rI pneumatically diluted with nitrogen to an oxygen concentration of approximately 4% by volume.
The coke-adhered catalyst was regenerated at 740° C. under approximately the same pressure as that of the reactor by supplying about 130 g/h of steam and about 130 g/+1 of steam. Table 3 shows the compositions of the raw oil and produced oil. By the method of the present invention, membrane alkyl hydrogenation could be carried out continuously by directly using feedstock oil containing sulfur and nitrogen compounds.

Table 1 Table 2 Table 3 Catalytic cracking circulating oil composition Naphthalene Weight% 6.4 Methylnaphthalene 〃14.5 Dimethylnaphthalene 〃 24.4 Trimethylnaphthalene 〃6.9 Total
100. O8 content weight%
0. 2N content Weight ppm 210 Table 4 Produced oil composition Naphthalene Weight% 67.4 Methylnaphthalene 〃 8゜9 Dimethylnaphthalene 〃 0.8 Trimethylnaphthalene
〃0.6 Benzene, toluene, xylene 〃17
．． 0+,

Claims (1)

[Claims] 1. A catalyst consisting of vanadium supported on alumina particles (however, the vanadium content in terms of metal vanadium is 3.
A method for hydrogenation membrane alkylation, characterized in that dealkylation is carried out by contacting an alkyl aromatic compound or a feedstock oil containing the same with an alkyl aromatic compound or a feedstock oil containing the same in the presence of hydrogen at 450 to 680°C. 2. The catalyst has a weight average diameter of 25 to 250 μm and a bulk density of 0.3.
~1.5g/cm^3, pore volume 0.1-1.5cm^
3/g, the hydrogenation membrane alkylation step is carried out in a fluidized bed reaction zone of catalyst particles for hydrogenation membrane alkylation, and the catalyst on which the coke produced in this step is precipitated is extracted from the reaction zone, 2. The hydrogenation membrane alkylation method according to claim 1, wherein the particles are regenerated in a fluidized bed state in a separate reaction zone, and the treated particles are returned to the hydrogenation membrane alkylation step.