JP2791328B2 - Method for producing dialkylnaphthalene - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transalkylation of a monoalkylnaphthalene having 1 to 4 carbon atoms of a naphthalene or an alkyl group by transalkylation of an alkyl group having 1 to 4 carbon atoms. The present invention relates to a method for producing dialkylnaphthalene. [0002] Various catalysts and processes have been disclosed in many literatures and patents for the alkylation of aromatic hydrocarbons with olefins or lower alcohols, but polycyclic aromatic hydrocarbons such as naphthalene Alternatively, the direct methylation reaction of α- or β-monoalkylnaphthalene with methanol has a drawback of low conversion activity and low selectivity to dimethylnaphthalene. In the specification of Japanese Patent Publication No. 53-5293,
A method for producing methylnaphthalene by transmethylating naphthalene with polymethylnaphthalene or polymethylbenzene in the presence of a silica-alumina catalyst is described.
Alternatively, dimethylnaphthalene was not obtained only with β-monomethylnaphthalene. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for efficiently producing a dialkylnaphthalene having an alkyl group having 1 to 4 carbon atoms, which has recently been used in various applications. According to the present invention, there is provided a method for producing a dialkylnaphthalene having 1 to 4 carbon atoms in an alkyl group, comprising the steps of: preparing naphthalene and / or a monoalkylnaphthalene having 1 to 4 carbon atoms in an alkyl group; A polyalkylbenzene having 1 to 4 carbon atoms in the alkyl group 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 simultaneously with silica-titania, silica-alumina,
The reaction is carried out by contacting with one or more solid acid catalysts selected from alumina-boria and a crystalline aluminosilicate having an inlet pore diameter of 5.8 angstroms or more, separating and recovering the dialkylnaphthalene formed, And circulating other naphthalenes and polyalkylbenzene to the reaction step. The process for producing dimethylnaphthalene using monomethylnaphthalene, polymethylbenzene and methanol will be described with reference to FIG. 1. In a transalkylation reaction column 1, monomethylnaphthalene (MMN), line 3 And circulating polymethylbenzene, etc., and if necessary, replenishment polymethylbenzene (PMB) from the line 4 to be brought into contact with the catalyst. Methanol may be fed together with monomethylnaphthalene and polymethylbenzene, but it is better to feed it separately from the line 12 to the catalyst layer of the reaction tower 1 as shown in FIG. In the case of this process, the molar ratio of monomethylnaphthalene to polymethylbenzene is preferably 1 or less. The reaction product is sent to a distillation column 5, heavy components are supplied from a line 6, trimethylnaphthalene (TMN) from a line 7, and dimethylnaphthalene (DM
N), unreacted monomethylnaphthalene (MM
N) and naphthalene (N), toluene (T), xylene (X), unreacted trimethylbenzene (TMB) and tetramethylbenzene (TEMB) are taken out of line 10, and all components other than dimethylnaphthalene are taken from line 3 to the reaction tower. Circulate to 1. Among the raw materials, the monoalkylnaphthalene having 1 to 4 carbon atoms in the alkyl group may be either α-monoalkylnaphthalene or β-monoalkylnaphthalene, and a mixture of one or more of these with 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 or a mixture of two or more of dialkylbenzene, trialkylbenzene and tetraalkylbenzene is used. The molar ratio of naphthalene and / or monoalkylnaphthalene to polyalkylbenzene is from 0.2 to 5, preferably from 0.5 to 2. [0010] As the solid acid catalyst, silica-titania,
4. Silica-alumina, alumina-boria, or those having a Group VIII metal supported thereon, or having an inlet pore diameter of 5.
8 Å or more crystalline aluminosilicate,
Specifically, it is ZSM-5, mordenite, L-type zeolite, or Y-type zeolite, and is H-type or Ia, IIa,
HY-type zeolites, silica-titania, alumina-boria, or mordenite are particularly preferable, such as those obtained by exchanging or supporting a group VIII or rare earth element. One or more solid acid catalysts selected from these are used. [0011] The reaction temperature is 150 to 500 ° C, preferably 200 to 450 ° C. At 150 ° C or lower, the reaction activity tends to decrease, and at 500 ° C or higher, catalyst deterioration due to coke deposition tends to increase. Reaction pressure is normal pressure to 5
0 kg / cm ² G, preferably ^{2 to} 30 kg / cm ² G
It is. Although the reaction proceeds even at normal pressure, it is desirable to perform the reaction under a slight pressure so that the catalyst surface 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 . Although hydrogen may not be allowed to coexist in the reaction system,
In order to suppress coke precipitation, it is desirable to make hydrogen coexist. The H ₂ / reaction raw material molar ratio is 1-20. The desired 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. 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 are specifically described below. Example 1 1.0 g of commercially available HY-type zeolite (SiO ₂ / Al ₂ O ₃ = 5.6) sized to 16-32 mesh
Was charged into a reactor having an inner diameter of 4 mmφ, and then subjected to a pretreatment for 1 hour at 500 ° C. in an air flow. Next, the reaction temperature was increased to 43.
0 ° C., β-methylnaphthalene and 1,2,4-
Trimethylbenzene (1: 1 mol) was converted to WHSV = 2.8.
Supplied to HR ^-1 . The reaction pressure was normal pressure.
The reaction results obtained by analyzing the product 30 minutes after the start of the reaction using a gas chromatograph are shown in Tables 1 and 2. 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 (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
It was heated to 5 to 98 ° C to precipitate. The precipitate was filtered, dried at 120 ° C. overnight and then calcined at 500 ° C. for 3 hours in air. The composition of the catalyst thus obtained is T
iO ₂ : SiO ₂ = 9: 1. Table 2 shows the results of the same test as in Example 1 except that this catalyst was used and WHSV was set to 1.4 HR ^-1 . Example 3 Boric acid was impregnated with alumina hydrate so that the B ₂ O ₃ content became 15 wt%, then dried at 130 ° C. overnight, and then at 500 ° C. for 1 hour in air. Fired. 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. 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. 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. Example 6 Example 5 except that the reaction temperature was 370 ° C.
Table 2 shows the results of the same tests. Example 7 Example 5 except that the reaction temperature was 330 ° C.
Table 2 shows the results of the same tests. Example 8 Using commercially available mordenite as a catalyst,
Table 2 shows the results of the same test as in Example 2 except that the reaction temperature was 460 ° C. EXAMPLE 9 HZS Synthesized According to Mobile Patent
Example 2 except that M-5 type zeolite was used as a catalyst.
Table 2 shows the results of the same tests. Example 10 A test similar to that of Example 2 except that 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 mol. Are shown in Table 2. EXAMPLE 11 A 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 was used at a ratio of 1: 1 mol. [Table 2] Example 12 Toluene was methylated with methanol. After using HY-type zeolite as a catalyst and performing the same pretreatment as in Example 1, toluene: methanol =
WHSV was supplied at a ratio of 2: 1 so as to be 1.0 HR ^-1 . The reaction pressure was normal pressure. The reaction results obtained by analyzing the product 30 minutes after the start of the reaction using a gas chromatograph are shown in Table 3. 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). [Table 3] Since the same catalyst can be used as the catalyst used in the transalkylation reaction and the catalyst used in the alkylation reaction, naphthalene and / or monoalkylnaphthalene, polyalkylbenzene and olefin or lower alcohol can be simultaneously used as a solid acid catalyst. To form dialkylnaphthalene by transalkylation reaction of naphthalene and / or monoalkylnaphthalene with polyalkylbenzene, and polyalkylene by reaction of olefins or lower alcohol with benzenes having reduced alkyl groups. The regeneration of the alkylbenzene can be performed 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 uses 450 ° C. HZ as 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%. According to the present invention, a dialkylnaphthalene is produced by a transalkylation reaction of naphthalene and / or a monoalkylnaphthalene with a polyalkylbenzene, and the resulting benzene and olefin or lower olefin having a reduced alkyl group. Regeneration of polyalkylbenzene by reaction with alcohol can be performed simultaneously in the same reaction tower. Further, dialkylnaphthalene can be produced with a higher selectivity than the conventional method.

[Brief description of the drawings] FIG. 1 is a diagram for explaining the method of the present invention.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C07C 2/86 C07C 2/86 6/12 6/12 // C07B 61/00 300 C07B 61/00 300

Claims (1)

(57) [Claims] Naphthalene and / or alkyl group having 1 to 4 carbon atoms
The monoalkylnaphthalene and the alkyl group have 1 to 1 carbon atoms
4 polyalkylbenzene and alkyl group having 2 to 2 carbon atoms
The olefin of 4 or the lower alcohol having 1 to 4 carbon atoms in the alkyl group is simultaneously selected from silica-titania, silica-alumina, alumina-boria and crystalline aluminosilicate having an inlet pore diameter of 5.8 angstroms or more. The reaction is carried out by contacting with one or more solid acid catalysts, the resulting dialkylnaphthalene is separated and recovered, and naphthalenes other than dialkylnaphthalene and polyalkylbenzene are circulated to the reaction step. Production methods of dialkylnaphthalenes of Nos. 1 to 4. 2. The method for producing a dialkylnaphthalene according to claim 1, wherein the crystalline aluminosilicate having an inlet pore diameter of 5.8 angstroms or more is selected from the group consisting of Y-type zeolite, ZSM-5, and mordenite.