JPH0733690A - Production of dialkylnaphthalene - Google Patents

Abstract

PURPOSE:To provide an efficient process for the production of dialkylnaphthalenes containing 1-4C alkyl groups and having gradually expanding application fields. CONSTITUTION:Naphthalene and/or a monoalkylnaphthalene containing 1-4C alkyl group, a polyalkylbenzene containing 1-4C alkyl groups and an olefin containing 2-4C alkyl groups or a lower alcohol containing 1-4C alkyl groups are simultaneously brought into contact with one or more kinds of solid acid catalysts selected from silica-titania, silica-alumina, alumina-boria and crystalline aluminosilicate having an inlet pore diameter of >=5.8Angstrom , the produced dialkylnaphthalenes are separated and recovered and the naphthalenes and polyalkylbenzenes other than dialkylnaphthalene are recycled to the reaction process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a dialkylnaphthalene having an alkyl group having 1 to 4 carbon atoms by transalkylation of naphthalene or a monoalkylnaphthalene having an alkyl group having 1 to 4 carbon atoms. .

[0002]

2. Description of the Related Art Regarding the alkylation of aromatic hydrocarbons with olefins or lower alcohols, various documents and patents disclose various catalysts and processes, but polycyclic aromatic hydrocarbons such as naphthalene or α- Alternatively, the direct methylation reaction of β-monoalkylnaphthalene with methanol has the drawbacks of low conversion activity and low selectivity to dimethylnaphthalene.

Further, Japanese Patent Publication No. 53-5293 discloses that
A method of reacting naphthalene with polymethylnaphthalene or polymethylbenzene in the presence of a silica-alumina catalyst to transmethylate to produce methylnaphthalene is described, but according to the example, α-
Alternatively, only β-monomethylnaphthalene has not been obtained for dimethylnaphthalene.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for efficiently producing a dialkylnaphthalene having an alkyl group having 1 to 4 carbon atoms, the use of which is expanding recently.

[0005]

The method for producing a dialkylnaphthalene having 1 to 4 carbon atoms in the alkyl group of the present invention comprises a naphthalene and / or a monoalkylnaphthalene having 1 to 4 carbon atoms in the alkyl group and an alkyl group. Silica-titania, silica-alumina, a polyalkylbenzene having 1 to 4 carbon atoms and an olefin having 2 to 4 carbon atoms in the alkyl group or a lower alcohol having 1 to 4 carbon atoms in the alkyl group are simultaneously added.
The resulting dialkylnaphthalene is separated and recovered by contacting it with one or more solid acid catalysts selected from the group consisting of alumina / boria and crystalline aluminosilicate having a pore size of 5.8 angstroms or more. Other than naphthalene and polyalkylbenzene are circulated in the reaction step.

In the case of producing dimethylnaphthalene using monomethylnaphthalene, polymethylbenzene and methanol, this process will be described with reference to FIG. 1. In the transalkylation reaction column 1, line 2 to monomethylnaphthalene (MMN), line 3 The circulating polymethylbenzene or the like and, if necessary, supplementary polymethylbenzene (PMB) are fed from the line 4 to bring them into contact with the catalyst. Methanol may be fed together with monomethylnaphthalene and polymethylbenzene, but as shown in FIG. 1, it is better to divide and feed from the line 12 into the catalyst layer of the reaction column 1. In this process, the molar ratio of monomethylnaphthalene and polymethylbenzene is preferably 1 or less. The reaction products are sent to the distillation column 5, and heavy components are fed from the line 6, trimethylnaphthalene (TMN) from the line 7, and dimethylnaphthalene (DM) which is a target substance from the line 8.
N), from line 9 unreacted monomethylnaphthalene (MM
N) and naphthalene (N), toluene (T), xylene (X), unreacted trimethylbenzene (TMB) and tetramethylbenzene (TEMB) are taken out from the line 10, and all components other than dimethylnaphthalene are taken from the line 3 Cycle to 1.

Among the raw materials, the monoalkylnaphthalene whose alkyl group has 1 to 4 carbon atoms may be either α-monoalkylnaphthalene or β-monoalkylnaphthalene, and one or a mixture of these and naphthalene may be used. Used as a raw material.

As the polyalkylbenzene having an alkyl group having 1 to 4 carbon atoms as an alkylating agent, one kind or a mixture of two or more kinds of dialkylbenzene, trialkylbenzene and tetraalkylbenzene is used.

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,
4. Silica / alumina, alumina / boria, or those in which Group 8 metal is supported, or the inlet pore diameter is 5.
Crystalline aluminosilicate of 8 Å or more,
Specifically, ZSM-5, mordenite, L-type zeolite, or Y-type zeolite, H-type or Ia, IIa,
Preferred are HY-type zeolite, silica-titania, alumina-boria, and mordenite, in which group 8 or rare earth elements are exchanged or supported. One or more solid acid catalysts selected from these are used.

The reaction temperature is 150 to 500 ° C, preferably 200 to 450 ° C. At 150 ° C or lower, the reaction activity tends to be low, and at 500 ° C or higher, the catalyst deterioration due to coke precipitation tends to increase. Reaction pressure is normal pressure to 5
0 Kg / cm ² G, preferably ^{2 to} 30 Kg / cm ² G
Is. Although the reaction proceeds even under normal pressure, it is desirable to carry out under a slight pressure so that the surface of the catalyst can be kept wet with the raw materials and products. The WHSV is 0.1 to 20 HR ^-1 , preferably 0.5 to 5 HR ^-1 .

Hydrogen does not have to coexist in the reaction system,
In order to suppress coke precipitation, it is desirable to make hydrogen coexist. H ₂ / reactant molar ratio is 1 to 20.

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

The production of dimethylnaphthalene by transalkylation of β-methylnaphthalene in Examples 1 to 11 and the regeneration of polymethylbenzene by methylation of toluene with methanol in Examples 12 to 17 will be specifically described below.

[0015]

Example 1 1.0 g of commercially available HY-type zeolite (SiO ₂ / Al ₂ O ₃ = 5.6) sized to 16 to 32 mesh
Was charged into a reactor having an inner diameter of 4 mmφ, and pretreatment was performed at 500 ° C. for 1 hour under air flow. Then set the reaction temperature to 43
Set to 0 ℃, β-methylnaphthalene and 1,2,4-
Trimethylbenzene (1: 1 mol) was added to WHSV = 2.8.
It was supplied so as to be HR ^-1 . The reaction pressure was atmospheric pressure.
Tables 1 and 2 show the reaction results obtained by analyzing the products 30 minutes after the start of the reaction using a gas chromatograph. The reaction results are shown for the case where unreacted substances are not recycled to the transalkylation reaction step.

[0016]

[Table 1]

[0017]

Example 2 (C ₂ H ₅ ) ₄ · SiO _{4 in 5} L of distilled water
50 cc, 230 cc of TiCl ₄ and 30 cc of concentrated hydrochloric acid were added, followed by 900 g of urea. This for 12 hours, 9
The mixture was heated to 5 to 98 ° C to cause precipitation. The precipitated product was filtered, dried overnight at 120 ° C., and then calcined in air at 500 ° C. for 3 hours. The composition of the catalyst thus obtained is T
The ratio of iO ₂ : SiO ₂ was 9: 1. Table 2 shows the results of the same tests as in Example 1 except that this catalyst was used and WHSV = 1.4 HR ⁻¹ .

[0018]

Example 3 Alumina hydrate was impregnated with boric acid so as to have a B ₂ O ₃ content of 15 wt%, dried at 130 ° C. for one day and then calcined in air at 500 ° C. for 1 hour. Shown this way results except that the _{Al 2 O 3 · B 2 O} 3 obtained was used as a catalyst was subjected to the same tests as in Example 2 in Table 2.

[0019]

Example 4 Table 2 shows the results of the same tests as in Example 2 except that commercially available SiO ₂ .Al ₂ O ₃ was used as a catalyst.

[0020]

Example 5 Table 2 shows the results of the same tests as in Example 2 except that a commercially available HY-type zeolite was used as a catalyst.

[0021]

Example 6 Example 5 except that the reaction temperature was 370 ° C.
Table 2 shows the result of a test similar to the above.

[0022]

Example 7 Example 5 except that the reaction temperature was 330 ° C.
Table 2 shows the result of a test similar to the above.

[0023]

Example 8 Using commercially available mordenite as a catalyst,
Table 2 shows the results of the same tests as in Example 2 except that the reaction temperature was 460 ° C.

[0024]

Example 9 HZS Synthesized According to Mobile's Patent
Example 2 except that M-5 type zeolite was used as a catalyst
Table 2 shows the result of a test similar to the above.

[0025]

Example 10 The same test as in Example 2 was conducted except that a commercially available HY-type zeolite was used as a catalyst and xylene was used as an alkylating agent in a ratio of β-methylnaphthalene: xylene = 1: 1. The results are shown in Table 2.

[0026]

Example 11 Commercially available HY-type zeolite was used as a catalyst, tetramethylbenzene was used as an alkylating agent, and β-
Table 2 shows the results of the same test as in Example 2 except that methylnaphthalene: tetramethylbenzene = 1: 1 mol was used.

[0027]

[Table 2]

[0028]

Example 12 Toluene was methylated with methanol. Using HY zeolite as a catalyst and performing the same pretreatment as in Example 1, toluene: methanol =
It was supplied so that WHSV = 1.0 HR ⁻¹ at a ratio of 2: 1. The reaction pressure was atmospheric pressure. Table 3 shows the reaction results obtained by analyzing the product 30 minutes after the start of the reaction using a gas chromatograph.

[0029]

Examples 13 to 17 RE (rare earth metal exchange) Y-type zeolite (Example 13), LaY-type zeolite (Example 14), HZSM-5 (Example 15), Al
₂ O ₃ .B ₂ O ₃ (Example 16), TiO ₂ : SiO ₂
Table 3 shows the results of the same test as in Example 12 using (Example 17).

[0030]

[Table 3]

As the catalyst used in the transalkylation reaction and the catalyst used in the alkylation reaction can be the same, naphthalene and / or monoalkylnaphthalene, polyalkylbenzene and olefin or lower alcohol are simultaneously added to the solid acid catalyst. By contacting it with naphthene and / or monoalkylnaphthalene and polyalkylbenzene to form a dialkylnaphthalene, and the resulting alkyl group-reduced benzenes and olefins or lower alcohols The regeneration of alkylbenzene can be carried out simultaneously in the same reaction column.

When the process shown in FIG. 1 is assembled based on the test results shown in Tables 2 and 3, the transalkylation step uses HY type zeolite as a catalyst at 430 ° C., and the methylation step takes 450 ° C. HZ as a catalyst
Using SM-5, polymethylbenzene: methanol =
When the ratio is 2: 1 (molar ratio), the selectivity of dimethylnaphthalene to methanol is about 48%.

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

[0034]

INDUSTRIAL APPLICABILITY In the present invention, the production of dialkylnaphthalene by the transalkylation reaction of naphthalene and / or monoalkylnaphthalene with polyalkylbenzene, and the resulting benzenes with reduced alkyl groups and olefins or lower alcohols The regeneration of polyalkylbenzene by the reaction can be carried out simultaneously in the same reaction tower. Further, dialkylnaphthalene can be produced with a high selectivity as compared with the conventional method.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a method of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C07C 2/86 6/12 // C07B 61/00 300

Claims (2)

[Claims] 1. A monoalkylnaphthalene having naphthalene and / or an alkyl group having 1 to 4 carbon atoms, a polyalkylbenzene having an alkyl group having 1 to 4 carbon atoms, and an olefin or an alkyl group having an alkyl group having 2 to 4 carbon atoms. Has 1 carbon
4 to 4 lower alcohols are simultaneously contacted with one or more solid acid catalysts selected from silica / titania, silica / alumina, alumina / boria and crystalline aluminosilicates having an entrance pore size of 5.8 Å or more to react. And the generated dialkylnaphthalene is separated.
A method for producing a dialkylnaphthalene having an alkyl group having 1 to 4 carbon atoms, which comprises recovering and recycling naphthalenes other than dialkylnaphthalene and polyalkylbenzene in a reaction step. 2. A crystalline aluminosilicate having an inlet pore diameter of 5.8 Å or more is Y-type zeolite, ZS.
The method for producing a dialkylnaphthalene according to claim 1, which is selected from the group consisting of M-5 and mordenite.