JPS6263528A - Production of p-xylene - Google Patents

Abstract

PURPOSE:To obtain p-xylene in high conversion, by modifying a catalyst containing a crystalline aluminosilicate with phosphorus oxide, etc., treating the modified catalyst with a silicic acid ester in liquid phase and methylating toluene in vapor phase in the presence of the above catalyst. CONSTITUTION:A catalyst containing crystalline aluminosilicate modified with phosphorus and/or its oxide (e.g. zeolite ZSM-5) is treated with a silicic acid ester in liquid phase. p-xylene is produced by methylating toluene with a methylation agent (e.g. methanol, dimethyl ether, etc.) in vapor phase in the presence of the above treated catalyst. The methylation is carried out at 300-700 deg.C and a weight-hour space velocity of 1-800/hr at a methylation agent/toluene molar ratio of 0.01/n-2/n (n is 2 when the methylation agent is dimethyl ether and is 1 otherwise). The methylation may be performed in the presence of hydrogen.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Application Field The present invention relates to a method for producing P-ginle, /. More specifically, the production of methyl The present invention relates to a method for producing P-xylene by converting it into P-xylene.

P-xylene is an extremely useful compound industrially because it can be derived from terephthalic acid or themphthalic dimethyl ester, which is a raw material for polyester.

Conventionally, P-xylene/ is obtained by separation and isomerization from a C8 aromatic hydrocarbon fraction, which is a petrochemical derivative, through °C, and it has been industrially produced in large quantities by this method. .

On the other hand, as a method for producing alkyl-substituted aromatic hydrocarbons such as P-xylene, there have recently been many methods (proposed) of alkylating aromatic hydrocarbons with various alkylating agents. As described in Japanese Patent No. 53-12816 (using crystalline aluminosilicate zeolite as a catalyst, toluene or ethylbenzene is converted into ethylene,
Ethyl alcohol, hydrogenated ethyl, diethyl ether, and other ethyl agents can be converted into ethyl toluene or diethylbenzene! ! - A method of manufacturing is disclosed. Although this method is excellent in that it can produce P-ethyltoluene or P-diethylbe/ze/ with relatively high selectivity, it is not suitable for producing xylenes, especially P-xylene/.

Further, JP-A-52-120292 discloses antimono, phosphorus, polyIj:/, and magnesium.

Toluene in the presence of a crystalline Jl aluminosilicate zeolite catalyst modified with various substances such as amorphous silica
A process for producing P-dialkylbenzene by alkylation with an alkylating agent having 4 carbon atoms is disclosed. The method for producing P-xylene according to the above proposal is as follows:
Although the ratio of xylene and the conversion rate of toluene to xyleno are less than 5 points compared to other methods, it is still within the range of 1) - xylene concentration and Conversion rate/conversion rate was not obtained.

In addition, the present inventors have also conducted research on an industrially advantageous method for producing iJ-diyanren by methylation of toluene. Dear,
We have already proposed a method in which both the toluene conversion rate and the P If the reaction is carried out using a nosilicate catalyst and the toluene conversion rate is set to a low value of about 1000 to 2000 ℃ by expressing the contact time, well, it is relatively P-17V/ Although a highly concentrated xyleno isomer mixture was obtained, when the reaction time was increased to increase the toluene conversion rate, the P-xylene concentration in the generated xyleno isomer mixture tended to decrease. .

(C1 Purpose of the Invention) Therefore, the present inventors have discovered that P-
Regarding the production method of xylene, we have discovered a production method that provides even higher P-xylene 9 degrees and a higher toluene conversion rate (as a result of extensive research, we have arrived at the present invention).

i) Structure and effect of the invention That is, the present invention is based on phosphorus and/or its molybdenum.
Methylating toluene with a methylating agent in the gas phase in the presence of a catalyst obtained by treatment with a silicate ester in the liquid phase containing a modified crystalline aluminosilicate zeolite catalyst. This is a method for producing P-xylene.

The present invention will be explained in more detail below.

In the present invention, zeolites, which are the basis of the catalyst, can be used, but in general, the cation sites mainly contain hydrogen precursors such as hydrogen ions/or ammonium ions, and the silica/fluoride molar ratio is at least 10. Olite has a silica/alumina molar ratio of 15 to 5000.
, particularly preferably 20 to 3000°C, i! 11 HatakeIt is called a silica-based zeolite. Many such zeolite catalysts have been proposed in the past8.
Preferably, the catalyst of the present invention satisfies the silica/alumina molar ratio range as described above. ') IJ'A's ZS
Preferred examples include M-series heptaolide and Zeta-series zeolite developed by Inverial Chemical I/Tastry Limited. In particular, as an example of ZSM-based zeolite, ZSM-5 (U.S. Patent No. 3
702886), ZSM-11 (see US Pat. No. 3,709,979), ZSM-12 (see US Pat. No. 3,832,449), ZSM-35,
ZSM-38 and the like are preferred, and examples of the →zeta-based zeolaite include Zeta I (see Japanese Patent Application Laid-Open No. 51-67299) or Zeta-3 (Japanese Patent Laid-Open No. 51-67298).
Reference No. 8) is preferred.

In addition, heptaolide and L℃ TP-1 series zeolite discovered and already proposed by the present inventors (Japanese Unexamined Patent Publication No. 137500/1989
(Refer to the publication) can also be used. Kalo TP-1
The zeolite catalyst is a raw material mixture containing nithiol, alumina, alkali and water.

A zeolite catalyst obtained by heating an organic sulfur compound such as sulfides, sulfokinds, sulfo/s or thiophenols at a temperature and for a time sufficient to form crystalline aluminium/ion lithoseolite. . The method for producing Kalo TP-1 zeolite and its properties are described in detail in the above-mentioned specification of JP-A-Sho.

In the present invention, the use of ZSM5 shows the most excellent effect among the above-mentioned zeolites. It was treated with an acid ester at °C.

The K for modifying the crystalline aluminum 7-silicate zeolite with υ and/or its oxide is superior to the conventional modification method, and the crystalline aluminosilicate zeolite is 9E.
K, phosphorus compounds (e.g. phosphoric acid, phosphorous ammonium,
impregnated with a solution of
Filtration or something? It is best to evaporate the a medium, dry it, and then sinter it in an oxygen atmosphere. In this case, phosphorus and/or its oxide is phosphorus atom (U, 1 to 30) [t%, preferably 1 to 2 t%, per 1 weight of the crystalline aluminosilicate.
It is desirable that the content be 0%.

The silicate ester used in the present invention generally has the chemical formula 5l
(OR)4 (R is a methyl group or an ethyl group.

(lower alkyl groups such as propyl and butyl)
Those represented by are preferred. In order to treat the modified crystalline aluminosilicate with the silicate ester and obtain the effects of the present invention, the contact M between the silicate ester and the modified crystalline aluminosilicate may be carried out in a liquid phase.

That is, the modified crystalline alkinosilicate biolite is contained in a bath solution containing the silicate ester for a certain period of time at a temperature below the boiling point of the silicate ester, and then dried or evaporated. All you have to do is let it bake. At this time, factors that affect the catalytic performance include the concentration of the silicate ester solution, type I solvent, dispersion of the silicate ester on the summer crystalline aluminone silicade, impregnation time and temperature, and drying or calcination conditions, such as time,
Temperature, atmosphere, etc. may be mentioned, but these conditions vary widely depending on the en species of the crystalline aluminone licade, the amount of modification of phosphorus and/or its oxide, the type of silicate ester, etc., and cannot be specified. isn't it.

It is also possible to carry out the silicate ester treatment repeatedly in order to obtain the desired catalytic performance.

Further, in the present invention, it is preferable that the crystalline reminon ligated zeolite modified with phosphorus or its oxide is subjected to steam treatment before the silicate ester treatment. Such steam treatment
00゛C1 Preferably a temperature of 200-6oo℃, 0.1
~20 hours, preferably ~I5 treatment time, further Q
~10 kg7 dtG, preferably 0-5 kg/f
It is desirable to perform this at a water vapor partial pressure of f1G. Furthermore, the substance used in the steam treatment is not limited to water, and compounds that generate water at ℃ under the treatment conditions, such as various alcohols, or aqueous solutions thereof can also be used.

The modified olide-containing catalyst of the present invention may be in various forms (e.g., molded powder, pellets or tablets). It is also possible to use a mixture of natural fire-resistant inorganic gelatinized substances.

In that case, the content of the binder is 1 to 99% relative to the catalyst.
It is desirable that the content is 10 to 90 M%.

The methylation of the present invention uses a catalyst containing crystalline aluminosilicate theolite modified as described above,
Toluene and the methylating agent are brought into contact in the gas phase. The methylating agent used in this case may be one that is used for methylating the carbon of aromatic hydrocarbons on the +S, - membrane surface (for example, methanol).

Methyl chloride, methyl bromide, dimethyl ether and the like are preferred, with methanol and dimethyl ether being particularly preferred. At this time, the molar ratio of methyl and other agents/toluene was 0.01
/n to 2/n, preferably 0.05/n
A range of -1/n is desirable. (However, n is 2 in the case of dimethyl ether, and 1 in other cases.
represents. ) In the present invention, the catalyst is brought into contact with toluene and the methylating agent in the gas phase at a time when the overlapping hourly space velocity gl-(WHSV) is 0.
．． 1 to] 000 hr-'. Here, wHsv refers to zeolite units (&
) of toluene in unit time (hr)
Define it as (, y) minus six. Preferred WH8V
Values range from 1 to 800 hr-', especially from 2 to 500 hr
-' range. WH3Vfii is 0,1 hr-'
If it is smaller than this, the intended purpose of the present invention cannot be achieved. On the other hand, if the WH8V value exceeds 1000 hr-', the contact time is too short and the conversion rate of C. toluene decreases, which is industrially disadvantageous.

The reaction is advantageously carried out in a hydrogen stream F.

In this case, the amount of hydrogen supplied is preferably in the range of 0.1 to 10 expressed as a hydrogen/toluene molar ratio. Furthermore, an inert gas such as nitrogen may be used as a diluent.

The reaction may also be carried out at a temperature in the range of 300 to 700°C, especially at 400°C.
It is advantageously carried out in the range ˜600-°C. Further, the pressure may be reduced, normal pressure, or increased pressure, but it is usually carried out at normal pressure to increased pressure, for example, a pressure of 1 to 70 atmospheres.

The reaction of the present invention can be carried out in either a fixed bed system or a fluidized bed system. Furthermore, as already proposed by the present inventors and described in Japanese Patent Application Laid-Open No. 58-35128,
According to the present invention, there are many advantages when using a multistage reaction system consisting of a plurality of fixed catalyst beds connected in series and separated from each other. At a higher Toluev conversion compared to
It is possible to obtain a reaction product having a P-xylene concentration of % or more, which is industrially advantageous.

Furthermore, the catalyst used in the present invention has a simple preparation method and excellent reproducibility, and from this point of view as well, it has little industrial value.

The method of the present invention will be described below with reference to Examples and Example V].

In addition, each field used in the examples and examples is defined as follows.

Reference Example 1 As disclosed in U.S. Pat.
was synthesized. After baking the composite at 500°C for 16 hours 3
094Y5 Judai no Kuichicent NH4 (J water f8 Kin 30
Ino was exchanged for 24 hours at 01 and 80°C. After that, wash thoroughly with water, dry at 100℃, and then dry at 500℃ for 1 hour.
It was baked for 6 hours.

Then add 1001 phosphorus to 1001 phosphorus/7nium 2.548
,? The above 1 (type Z SM-5 powder xz, o & tjI: suspended in a solution containing
After standing overnight under K heating, the water was evaporated using a rotary evaporator. It was then heated at 200C for 4 hours, and then fired at 500C for 16 hours in an air stream. As a result, the catalyst has 5.0 in terms of phosphorus atoms for Z SM -5! Contains t% of phosphorus and/or its oxides.

After molding the above catalyst, it was pulverized into 10 to 20 meshes. Hereinafter, this catalyst sample will be referred to as catalyst A.

Catalyst A 1.0& was packed into an atmospheric fixed bed flow reactor, and a mixture having a water/methanol volume ratio of 1 was supplied at 500° C. under hydrogen atmosphere for 20 hours. The water/methanol mixture feed rate was 5y/hour, and the hydrogen feed rate was 22 NCc/min. After a long time, it reached 590'C g g L, memenol/toluene/ratio (moles)]15. The hydrogen/toluene ratio (mol) was I/1°wnsv, and the toluene/toluene methylation reaction was carried out in the range of 5 to 20 hr-'.

Example 1 Catalyst A10.9 was packed into a fixed bed pressure distribution two-way wide device.
0 (1'c; temperature ratio of water/methanol is 1 under hydrogen flow)
The mixture was fed for 20 hours. The water/methanol mixture supply rate is #50y/min, and the hydrogen supply rate is 22ONcc/min.
Met. Catalyst that underwent the above 7KA gas treatment? See below
Call it H.

Catalyst B2& was impregnated in 50 ml of an isooctane solution containing silicon modified ethyl 5aj and maintained at a reflux temperature of 1 for 24 hours. The sample was then washed once and twice with 20 ml of ink.

After drying, it was dried for 24 hours at 100°C under a stream of cold air.

Water sample 1/'kt pressure fixed bed flow Nitanshi δ device is filled,
N, the temperature rose to 590'C under the air flow. Next, a methylation reaction of toluene was carried out under the same conditions as in Reference Example 1.

Example 2 The treatment described in Example 1 was applied to catalyst B for 5 minutes.
Toluene methylation reaction 16 was carried out under the same conditions as described in Reference Example 1 using a catalyst prepared by repeated application at ℃.

Reference example 1. 'J! : The results of Examples 1 and 2 are listed in Table 1 above. Table 2 also shows a comparison of other characteristic values when the toluene/' conversion rate was 11%. The results in Tables 1 and 2 demonstrate that the silicate ester treatment of the present invention significantly increases QP-xylene concentration without reducing toluene conversion.

Table 1 Table 2 Reference Example 2 Trimethyl linoate 0.5431 in Tolue/10011/
H-type ZSM-5 powder synthesized in Reference Example 1 was added to the solution containing t2.tt. o, 9fti! ! Made it muddy. This was left overnight while being heated to 70°C, and then the toluene was evaporated using a rotary evaporator. It was then heated at 200°C for 4 hours, and then fired at 500°C for 16 hours in an air stream. As a result, the catalyst has 1 heavy t in terms of phosphorus atoms for ZSM-5.
% of phosphorus and/or its oxides.

After the above-mentioned molding, it was pulverized into 10 to 20 meshes. This catalyst sample will be referred to as catalyst C hereinafter.

Catalyst CI& was packed into an atmospheric fixed bed flow reactor, and the methylation reaction of toluene/ was carried out under the same conditions as described in Reference Example 1.

Example 3 The ethyl silicate treatment described in Example 1 was carried out on Catalyst C, and the methylation reaction of toluene at °C was carried out under the same conditions as described in Reference Example 1 using the catalyst -cfAst.

Example 4 The silicate ester-treated tt catalyst C described in Example 1 was repeated twice and treated with 141AL catalyst under the same conditions as described in Example IK. A methylation reaction was performed.

Reference example 2. The results of Examples 3 and 4 are listed in Table 3 below. Table 4 also shows a comparison of other characteristic values when the toluene conversion rate is 13%.

Table 3 Table 4 Procedural amendment January 1985/, p day

Claims (1)

[Claims] 1. By treating a crystalline aluminosilicate-containing catalyst modified with phosphorus and/or its oxide with a silicate ester in the liquid phase, in the presence of the resulting catalyst, the gas phase A method for producing P-xylene, which comprises methylating toluene using a methylating agent. 2. The method for producing P-xylene according to item 1, wherein the crystalline aluminosilicate zeolite is zeolite ZSM-5. 3. The method for producing P-xylene according to item 1, wherein the crystalline aluminosilicate-containing catalyst contains 0.1 to 30% by weight of phosphorus and/or its oxide in terms of phosphorus atoms. 4. The method for producing P-xylene according to item 1, wherein the methylating agent is methanol and/or dimethyl ether. 5. The methylation is carried out at a weight hourly space velocity (WHSV) of 1 to 8.
2. The method for producing P-xylene according to item 1, which is carried out within a range of 00 hr^-^1. 6. The method for producing P-xylene according to item 1, wherein the methylation is carried out at a temperature in the range of 300 to 700°C. 7. P- according to item 1, wherein the methylation is carried out in the presence of hydrogen.
Method for producing xylene. 8. The methylation is carried out at a hydrogen/toluene molar ratio of 0.1 to 1.
8. The method for producing P-xylene according to item 7, which is carried out within a range of 0. 9. The methylation is carried out at a molar ratio of methylating agent/toluene of 0.
01/n to 2/n (where n is 2 when the methylating agent is dimethyl ether, and 1 in other cases.)
The method for producing P-xylene according to item 1, which is carried out within the following range.