JPS6314737A - Production of dialkylnaphthalene - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high efficiency, by trans-alkylating naphthalene or monoalkylnaphthalene in the presence of a solid acid catalyst, separating and recovering the objective dialkylnaphthalene and recycling the remaining part to the trans-alkylation step. CONSTITUTION:Naphthalene and/or a monoalkylnaphthalene are trans-alkylated by contacting with a polyalkylbenzene in the presence of a solid acid catalyst (especially preferably selected from HY zeolite, silica, titania, alumina, boria and mordenite), the produced dialkylnaphthalene is separated and recovered and the remaining polyalkylbenzene and naphthalenes other than dialkylnaphthalene are recycled to the trans-alkylation step. A benzene compound having reduced alkyl content by the trans-alkylation reaction may be regenerated by alkylation with olefin or lower alcohol and used as the polyalkylbenzene.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION INDUSTRIAL FIELD OF THE INVENTION The present invention relates to a method for producing dialkylnaphthalates by transalkylation of naphthalenes or monoalkylnaphthalenes.

Conventional technology Regarding the alkylation of aromatic hydrocarbons with olefins or lower alcohols, there are many literatures and patents that describe various catalysts.
Processes etc. are disclosed, but polycyclic aromatic hydrocarbons,
For example, the direct methylation reaction of naphthalene or .alpha.- or .beta.-monoalnaphthalene with methanol has the drawback of low conversion activity and low selectivity to dimethylnaphthalene.

Furthermore, the specification of Japanese Patent Publication No. 53-5293 describes a method for producing methylnaphthalene by reacting naphthalene with polymethylnaphthalene or polymethylbenzene in the presence of a silica-alumina catalyst and transmethylating it. According to the examples, only α- or β-monomethylnaphthalene was produced, and dimethylnaphthalene was not obtained.

The problem that the invention tries to solve! 4. An object of the present invention is to provide a method for efficiently producing dialkylnaphthalene, whose uses are recently expanding.

The method for producing dialkylnaphthalene of the present invention involves contacting naphthalene and/or monoalkylnaphthalene with polyalkylbenzene in the presence of a solid acid catalyst to carry out a transalkylation reaction, separating and recovering the dialkylnaphthalene produced, and It consists of recycling naphthalenes other than naphthalene and polyalkylbenzene to the transalkylation step.

Among the raw materials, the monoalkylnaphthalene may be either α-monoalkylnaphthalene or β-monoalkylnaphthalene, and those having an alkyl group having 1 to 4 carbon atoms are suitable. One or two of these and naphthalene
A mixture of more than one species is used as a raw material.

As the polyalkylbenzene which is the alkylating agent, one type or a mixture of two or more of dialkylbenzene, trialkylbenzene and tetraalkylbenzene is used. As the 14 prime number of the alkyl group of the polyargylbenzene, one having 1 to 4 is suitable.

The molar ratio of naphthalene and/or monoalkylnaphthalene to polyalkylbenzene is 0.2 to 5, preferably 0.
5 to 2.

As the solid acid catalyst, silica/titania, silica/alumina, alumina/boria, or a group II metal supported thereon, or a crystalline aluminosilicate with an inlet pore diameter of 5.8 angstroms or more, Specifically, ZSM-5, mordenite, L-type zeolite, or Y
Preferred are zeolites of the H type, such as Ia, Ila, group II, on which rare earth elements are exchanged or supported, particularly HY type zeolites, silica/titania, alumina/boria, or mordenite.

The reaction temperature is 150-500°C, preferably 200-45°C.
The temperature shall be 0°C. At 150°C or higher, the reaction activity tends to decrease, and at 500°C or higher, catalyst deterioration due to coke precipitation tends to increase.

The reaction pressure is normal pressure to 50Kg/cm2G, preferably 2 to
It is 30Kg/cm2G. Although the reaction proceeds under normal pressure, it is preferable to carry out the reaction under slight pressure so that the surface of the catalyst can be kept wet with raw materials and products.

wnsv is 0.1~20HR-1, preferably 0.5~
5HR-1.

Although it is not necessary to coexist hydrogen in the reaction system, it is preferable to coexist hydrogen in order to suppress coke precipitation.

The target product, dialkylnaphthalene, is separated and recovered from the product obtained by transalkylation under the above conditions. Naphthalenes other than dialkylnaphthalene, such as naphthalene, monoalkylnaphthalene and trialkylnaphthalene, and polyalkylbenzene in the product are recycled to the transalkylation step.

When manufacturing dialkylnaphthalene by transalkylation as described above is carried out industrially, naphthalene and/or monoalkylnaphthalene is brought into contact with polyalkylbenzene in the presence of a solid acid catalyst to perform a transalkylation reaction to produce dialkylnaphthalene. Dialkylnaphthalene is separated and recovered, naphthalenes other than dialkylnaphthalene and polyalkylbenzenes are recycled to the transalkylation process, and the benzenes whose alkylnaphthalenes have decreased are alkylated with olefins or lower alcohols to spontaneously produce polyalkylbenzenes. 11: Dialkylnaphthalene can be efficiently produced from naphthalene and/or monoalkylnaphthalene and olefin or lower alcohol by circulating the mixture into the transalkylation reaction step described in 1.

This process will be explained with reference to FIG. 1 when dimethylnaphthalene is produced using monomethylnaphthalene and methanol as starting materials.
Circulating polymethylbenzene, etc. from line 3, and replenishing polymethylbenzene (1'MB) from line 4 as necessary
is brought into contact with the catalyst to carry out the transalkylation reaction described above.

The product is sent to the first distillation column 5, the heavy fraction is sent from line 6, trimethylnaphthalene (TMN) is sent from line 7, and the product is sent to the first distillation column 5.
Dimethylnaphthalene (DMN), the target product, from line 9, unreacted monomethylnaphthalene (MMN) and naphthalene (N) from line 9, and unreacted trimethylbenzene (TMB) and tetramethylbenzene (TEM) from line 10.
B), benzenes with reduced methyl groups from line 11,
Namely, benzene (B), toluene (T) and xylene (X
).

BTX in line 11 is sent to the alkylation reaction tower 13 together with methanol from line 12, and brought into contact with an alkylation catalyst to methylate xylene and trimethylbenzene (TM
B), 4ft of polymethylbenzene such as tetramethylbenzea (TEMB) is heated, gas and water are separated in the separator 14, and then distilled in the second distillation column 15, and from the bottom of the column through the line 16, lyxylene, trimethyl Benzene, tetramethylbenzene, etc. are extracted and recycled as circulating polymethylbenzene through line 3 to transalkylation reaction tower 1.

Benzene and toluene are extracted from the top of the second distillation column 15 and circulated through a line 17 to the alkylation reaction column 13.

Note that trimethylnaphthalene (TMN) from line 7 separated in the first distillation column 5, monomethylnaphthalene (MMN) and naphthalene (N) from line 9, and line IO
Trimethylbenzene (TMB) and tetramethylbenzene (TEM B ) from the reactor are also circulated through line 3 to the transalkylation reaction tower 1 and involved in the transalkylation reaction again.

Regarding the reaction conditions in the alkylation reaction tower 13, the same catalyst as used in the transalkylation reaction can be used.

The olefins used to alkylate benzenes with reduced alkyl groups have 2 to 4 carbon atoms, and the lower alcohols have carbon atoms! -4 are suitable.

The optimum reaction temperature varies depending on the catalyst used, for example HY
Type zeolite is 200-400"C, ZSM-5 is 300-500"C, but generally 150-500"C,
It is preferably 200 to 450°C. Below 150°C, the reaction activity tends to decrease, and above 500°C, catalyst deterioration due to coke precipitation tends to increase.

The reaction pressure is normal pressure to 50Kg/cm2G, preferably 2 to
It is 30Kg/cm2G. Although the reaction proceeds under normal pressure, it is preferable to carry out the reaction under slight pressure so that the surface of the catalyst can be kept wet with raw materials and products.

WH3V is 0.1~20HR-1, preferably 0.5~
5 HR-1.

It is desirable that hydrogen coexist in the reaction system, and the H2/reaction raw material molar ratio is 1 to 20.

Below, in Examples 1-11, the production of dimethylnaphthalene by transalkylation of β-methylnaphthalene, and in Examples 12-17, the regeneration of polymethylbenzene by methylation of toluene with methanol.
Explain physically.

[Example 1] Commercially available HY type zeolite (S ioz /A1203 = 5.6) sized to 16 to 32 mesh.

After filling a reactor with an inner diameter of 4 mmφ with Og, 50
The 1111+iii treatment was carried out for 1 hour at 0° C. with air circulation.

Next, the reaction temperature was set at 430°C, and β-methylnaphthalene and 1,2.4-trimethylbenzene (1:1 mol) were supplied so that WH3V = 2.8HR-1.The reaction pressure was normal pressure. Tables 1 and 2 show the reaction results obtained by analyzing the product 30 minutes after the start of the 0 reaction using a gas chromatograph.

The reaction results are shown for the case where unreacted substances and the like are not recycled to the transalkylation reaction step.

Table 1 [Example 2] Add (C2Hs)4 ・SiO + 50 cc to 5 liters of distilled water
, 230 cc of TiCl* and 30 cc of concentrated hydrochloric acid were added, followed by 900 g of urea. Do this for 12 hours, 95-9
It was heated to 8°C to cause precipitation. After filtering this precipitated product,
It was dried at 0°C for a day and night, and then fired in air at 500°C for 3 hours. The composition of the catalyst thus obtained was TiO2
:5iO2=9:1. Using this catalyst, WH
Table 2 shows the results of the same test as in Example 1 except that 3V=1.4HR-1.

[Example 3] l Alumina hydrate was impregnated with boric acid so that the B2O3 darkness was 15 wL%, and then dried at 130°C for a day and night, and then calcined in air at 500°C for 1 hour. Table 2 shows the results of the same test as in Example 2 except that the thus obtained Al2O3.B2O3 was used as a catalyst.

[Example 41 Table 2 shows the results of the same test as in Example 2 except that commercially available 5i02.A l 20 s was used as the catalyst.

[Example 5] Table 2 shows the results of a test similar to Example 2 except that a commercially available HY type zeolite was used as a catalyst.

[Example 6] Table 2 shows the results of the same test as in Example 5 except that the reaction temperature was 370°C.

[Example 71 Table 2 shows the results of the same test as in Example 5 except that the reaction temperature was 330°C.

[Example 8] Using commercially available mordenite as a catalyst, the degree of 1 reaction source was reduced to 4.
Table 2 shows the results of the same test as in Example 2 except that the temperature was 60°C.

[Example 91 Table 2 shows the results of the same test as in Example 2 except that H2SM-5 type zeolite synthesized according to the Mopil patent was used as the catalyst.

[Example 101 Results of the same test as in Example 2 except that commercially available HY type zeolite was used as the catalyst and xylene was used as the alkylating agent at a ratio of β-methylnaphthalene:xylene = 1:1 mole] are shown in Table 2.

[Example 11] Same procedure as Example 2 except that commercially available HY type zeolite was used as a catalyst and tetramethylbenzene was used as an alkylating agent in a ratio of β-methylnaphthalene:tetramethylbenzene=l=1 mole. The results of the test are shown in Table 2.

[Example 12] Toluene was methylated with methanol. Using HY type zeolite as a catalyst and performing the same pretreatment as in Example 1, toluene:methanol-Ay=2+l
It was supplied so that WH3V = 1.0HR-1 at a ratio of MoJlz(7). The reaction pressure was normal pressure.

Table 3 shows the reaction results obtained by analyzing the product 30 minutes after the start of the reaction using a gas chromatograph.

[Examples 13 to 17] RE (rare earth metal exchanged) Y-type zeolite (Example 13), LaY-type zeolite (Example 14), H2 as a catalyst
SM-5 (Example 15), A120a 1IB20a
(Example 16), Ti0z:5i02 (Example 1
Table 3 shows the results of a test similar to that of Example 12 using Example 7).

Table 3 When the process shown in Figure 1 is assembled based on the test results shown in Tables 2 and 3, the transalkylation step is carried out at 430°C using HY type zeolite as a catalyst, and the methylation process is carried out at 430°C. The process was carried out at 450℃ using H2SM- as a catalyst.
5 using polymethylbenzene:methanol-2:l (
molar ratio), the selectivity of dimethylnaphthalene to methanol is about 48%.

On the other hand, when monomethylbenzene is directly methylated with methanol, the selectivity of dimethylnaphthalene to methanol is only about 20%.

The catalyst used in the transalkylation reaction and the catalyst used in the alkylation reaction can be the same, so the first
The process illustrated in the figure can be simplified to
Alternatively, monoargylnaphthalene, polyalkylbenzene, and olefin or lower alcohol are brought into contact with a solid acid catalyst simultaneously to produce dimethylnaphthalene through a transalkylation reaction between naphthalene and/or monomethylnaphthalene and polyalkylbenzene, and the resulting product. Regeneration of polyalkylbenzene by reacting benzenes with reduced alkyl groups with olefins or lower alcohols can be simultaneously carried out in the same reaction column.

To explain this process with reference to FIG. 2, monomethylnaphthalene (MMN) is introduced into the transalkylation reaction column 1 from line 2, and recycled polymethylbenzene, etc. are fed from line 3.
and polymethylbenzene (supplied from line 4 as necessary)
PMB) is introduced and brought into contact with the catalyst.

Although methanol may be fed together with monomethylnaphthalene and polymethylbenzene, it is better to feed it in parts from line 12 to the catalyst bed of reaction column 1, as shown in the second factor.

In this process, the molar ratio of monomethylnaphthalene to polymethylbenzene is preferably 1 or less.

The reaction product is sent to distillation column 5, heavy components are sent from line 6, trimethylnaphthalene (TMN) is sent from line 7, and trimethylnaphthalene (TMN) is sent from line 8.
unreacted monomethylnaphthalene (MMN) and naphthalene (N) from line 9, toluene (T), xylene (X), unreacted trimethylbenzene (TMB) and tetra Methylbenzene (TEMn) is taken out, and all components other than dimethylnaphthalene are recycled through line 3 to reaction column 1.

Compared to the conventional method, dialkylnaphthalene can be produced with a higher selectivity.

[Brief explanation of the drawing]

Figure 1 shows a transalkylation reaction in which naphthalene and/or monoalkylnaphthalene is brought into contact with polyalkylbenzene in the presence of a solid acid catalyst, and benzenes with reduced alkyl groups are separated from the reaction product. The process of alkylating with an olefin or lower alcohol to regenerate polyalkylbenzene and circulating it into the transalkylation reaction step is exemplified for the case of producing dimethylnaphthalene using monomethylnaphthalene and methanol as starting materials, Ru. FIG. 2 exemplifies the case where the two-stage reaction described above is carried out in one reaction column.

Claims (1)

[Scope of Claims] 1 Naphthalene and/or monoalkylnaphthalene is brought into contact with polyalkylbenzene in the presence of a solid acid catalyst to carry out a transalkylation reaction, and the resulting dialkylnaphthalene is separated and recovered, and other than dialkylnaphthalene is A method for producing dialkylnaphthalene, which comprises circulating naphthalenes and polyalkylbenzene in a transalkylation step. 2. The dialkylnaphthalene according to claim 1, wherein the polyalkylbenzene used in the transalkylation reaction is a polyalkylbenzene regenerated by alkylating benzenes whose alkyl groups have been reduced by the transalkylation reaction with an olefin or lower alcohol. manufacturing method. 3. The method for producing dialkylnaphthalene according to claim 1 or 2, wherein the solid acid catalyst is selected from the group consisting of HY type zeolite, silica titania, alumina boria, and mordenite. 4 Naphthalene and/or monoalkylnaphthalene, polyalkylbenzene, and olefin or lower alcohol are brought into contact with a solid acid catalyst at the same time to react, and the resulting dialkylnaphthalene is separated and recovered, and naphthalenes other than dialkylnaphthalene and polyalkylbenzene are reacted. A method for producing dialkylnaphthalene, which comprises circulating dialkylnaphthalene in a reaction process. 5. The method for producing dialkylnaphthalene according to claim 4, wherein the solid acid catalyst is selected from the group consisting of HY type zeolite, silica titania, alumina boria, and mordenite.