CS235566B1

CS235566B1 - Method of production of Csaromatic hydrocarbons

Info

Publication number: CS235566B1
Application number: CS518283A
Authority: CS
Inventors: Jozef Novansky; Pavol Hudec
Original assignee: Jozef Novansky; Pavol Hudec
Priority date: 1983-07-08
Filing date: 1983-07-08
Publication date: 1985-05-15

Abstract

Vynález sa týká sposobu výroby C8aromatických uhlovodíkov konverziou aromatickej suroviny na katalyzátore obsahujúcom aspoň jeden kov VI. a/alebo VIII. skupiny perlodickej sústavy, zeolit a pojivo při zvýšenej teplote a tlaku a za přítomnosti vodíka alebo vodík obsahujúceho plynu, pri ktorom sa súčasnej transalkylácii metylbenzénov, hydroalkylácii vyšších alkylbenzénov a hydrokrakovaniu nearomátov podrobuje aromatická frakcia, vriaca pri 140 až 215 °C, obsahujúca min. 60 % hmot. aromátov, pričom zdrojom tejto frakcie sú C9aromáty z produktov katalytického reformovania benzínov a/alebo z produktov izomerizácie Csaromátov a/alebo z produktov pyrolýzy a C9aromatické frakcie sa použijú celé alebo ich destilačné řezy, s výhodou medzi 150 a 195 °C.The invention relates to a method of producing C8 aromatic hydrocarbons by converting an aromatic raw material on a catalyst containing at least one VI metal. and/or VIII. perlodic system groups, zeolite and binder at elevated temperature and pressure and in the presence of hydrogen or hydrogen-containing gas, during which the aromatic fraction, boiling at 140 to 215 °C, containing min. 60% by weight aromatics, while the source of this fraction are C9 aromatics from the products of catalytic reforming of gasoline and/or from the isomerization products of Caromatics and/or from pyrolysis products and the C9 aromatic fraction is used whole or their distillation cuts, preferably between 150 and 195 °C.

Description

The present invention relates to a process for the production of an aromatic by subjecting a zeolite catalyst to a conversion of an aromatic feed, the base of which is the Csomomátov fraction of a gasoline reformer, an isomerization of a C5-aromatic, a pyrolysis, or a combination thereof, while simultaneously transalkylating the methylbenzene, hydrodealkylation of higher alkylbenzenes and hydrocracking of non-aromatics.

Cs aromatics are among the most important aromatic hydrocarbons in the petrochemical industry. Of these, p-xylene, which serves as a feedstock for the production of polystyrene materials and fibers, is of the utmost importance. The main source of Csaromátov is the reforming of gasoline. Thus, the total production of C 5 -acarates is limited by the amount and composition of the reformate produced, which is dependent on the total volume of crude oil processed.

If the requirements for Csaromates increase, the constant consumption of Csaromát may be covered by the process of disproportionation of toluene to benzene and xylenes (equal to 1) or by transalkylation of toluene with tri-methylbenzenes to xylenes (equation 2). subsequent disproportionation of the transalkylation of the primary products of these reactions results in a lower amount of higher alkylbenzenes, up to tetramethylbenzenes. which depends on the composition of the feedstock.

Disproportionation and transalkylation reactions utilize excess cheaper, and less chemically less utilized, toluene, and, in fact, petrochemically unused tri-methylbenzenes to produce the desired xylenes.

The disproportionation of toluene (equation 1) and the transalkylation of toluene with trimethylbenzenes (equation 2) are actually two extreme cases of advantageous processing of the aromatics Cz and Cana needed by Csaromates, and by conversion of toluene, about 55p. about 25 mol% of carbometates and 28 mol% of benzene, about 4 mol% of trimethylbenzenes and about 0.5 mol% of tetramethylbenzenes The addition of trimethylbenzenes to toluene increases the yield of Caaromats to 41 mol%. For example, 1 mol of benzene in the feedstock would only reduce the C9aromatic content of the products to as low as 24% by mol for pure trimethylbenzene as the substrate, and the content of tetramethylbenzenes and higher alkylbenzenes in the products would also increase.

The intermolecular transfer reactions of methyl groups require the presence of strong acid catalysts for their course. In the current period, zeolite catalysts are most suitable.

The present inventors describe the production of Ca-aromatics by disproportionation of pure toluene or by transalkylation of toluene with trimethylbenzenes in the presence of zeolite catalysts already in AO 212 946/1981.

The source of trimethylbenzenes in the refinery is C + 9aromatic fractions, which in addition to tri-methylbenzenes also contain a considerable amount of other Csaromates, mainly ethyl toluenes, and almost one third of their content, C 10+ aromatic compounds, in which the various types of aromatics are present. From these fractions, trimethylbenzenes can be obtained by distillation of such a concentration of trimethylbenzenes of up to 75% by weight, denoted as fractions of Csaromates, used for transalkylation with pure toluene for the production of Csaro- mates described in U.S. Pat. AO 212 946 (1981). The advantage of the process for the production of Csaromát's invention is the removal of the need to use pure toluene as the raw material for the transalkylation of toluene with trimethylbenzenes and, on the other hand, the most concentrated trimethylbenzenes of the C + 9aro-6 233568 math fraction. For the production of trans-alkylation of toluene with trimethylbenzene, only the C + 9 aromatic fraction containing other alkylbenzenes, in addition to trimethylbenzenes, can be used, whereby the required toluene for the transalkylation with trimethylbenzene is formed directly from the feedstock during the conversion of the feedstock.

The present inventors have found that, on the di-functional zeolite catalysts used for the transalkylation of methylbenzene, methyl group transfer, C2 alkyl groups and higher are unstable under conditions appropriate to the intermolecular transfer of the methyl groups; they are rapidly cleaved from the aromatic nucleus. In this way, ethyltoluenes are dealkylated to the desired toluene, while dimethylbenzenes are dealkylated to xylenes, propylbenzenes to benzene and the like. The C + 9 aromatic fractions are used for the transalkylation of either the whole as distillation residues from the gasoline reforming products, the C-aromatic isomerization products, and the benzene fraction of the pyrolysis products, generally in the range of 140 to 210 ° C, or more preferably up to 190 °. C, distillation free of the heaviest aromatics, which has a negative effect on the activity and viability of the catalyst. Furthermore, the inventors have found advantageous sources of light aromatic fractions which, in addition to toluene, optionally benzene, may also contain non-aromatics, C 7 aromatic aromatic esters may be C 5 -C 7 aromatics from the transalkylation process itself. It is also preferable to also recycle C + 9 analogs from the transalkylation products so that the celassurin can be transalkylated together with the recycled aromatic fractions of Cs and / or C 6 and / or C 9 and the desired Csaromates are isolated from the products. It is also preferable to remove C9 + aromatic recyclates from the transalkylation by distillation of the heaviest aromas boiling above 190 ° C.

SUMMARY OF THE INVENTION The present invention relates to a process for the preparation of Csaromates by simultaneous transalkylation of methylbenzenes, hydrodealkylation of alkylbenzenes and C2 + alkyls, and hydrocracking of non-aromatics in the presence of a difunctional zeolite catalyst containing 0.1 to 15% by weight of at least one metal. or 8 of the Periodic Table, 10 to 80% by weight of zeolite and 20 to 90% by weight of binder, at a temperature of 250 to 520 ° C, a pressure of 1.0 to 6.0 MPa, a space velocity of 0.5 to 8 h -1 in the presence of hydrogen or hydrogen-containing gas after hydrogen ratio: raw material 1 to 25: 1, wherein the base of the raw material for the transalkylate forms a C + 9 aromatic fraction from the reforming of the benzenes and / or the isomerization of Csaromate / or pyrolysis which may be used either as whole or as distillation residues boiling usually between 140 and 210 ° C, or more preferably fractions boiling between 140 and 190 ° C. Increasing the total production of Csaromates available for this basic feed add C7 and / or Cs aromatic fractions containing at least 40% by weight of aromatic hydrocarbons. It is also preferred to process the recyclates of C 8, C 7, and C 1-4 aromatic fractions from the transalkylation process itself.

In this way, the amount of "produced Csaromates" can be increased by treatment with C 18 aromatics together with the aromatic fractions of C 8, C 7 aromatics and recyclates of C 8, C 7 and C 9 aromatics.

The processes for producing Csaromatic hydrocarbons are exemplified by the following examples. Example 1

The Csaromate fraction boiling in the boiling range of 145 to 207 ° C, representing a distillation residue after redistillation of the product catalytic reforming of gasoline, has a temperature of 420 ° C, a pressure of 2.0 MPa, a velocity of 2.0 h "1 in the presence of hydrogen by hydrogen: raw material 10: 1 has undergone conversion on a catalyst containing 0.6% Pd on a mixture of 40% mordenite and 60% gamma-alumina (hot.%).

Table 1fold (weight%)

non-aromatic BOD TO CsA IPB nPB 2JET0 LTMB Cio + A raw material 0,9 - - products 2,7 5,5 15,7 Example 2 From the aromatic fraction of Csaromates and the distillation residue from distillation of productcatalytic reforming of petrol, boiling in the boiling range 145 up to 207 ° C, a fraction boiling in 4.0 1.5 6.3 25.2 30.3 31.7 21.3 - 1.0 15.4 25.7 11.8 range 150 to 188 3C. This narrower fraction was converted at a temperature of 405 ° C, a pressure of 2.5 MPa, a space velocity of 3.0 h -1 and a molar ratio of hydrogen: feed of 15: 1 on the same catalyst as in Example 1. The composition of the feedstock and the liquid reaction products is shown in Table 1. 2.

Claims

Table 2Composition (w / w) NonaBE TO CeA IPB nPB 2JETO LTMB Cio + A raw material 0.2 - - products 1.4 5.3 23.8 Example 3 From the aromatic fraction of Caaromates, the distillation residue from isomerate, a distillate fraction boiling in the range of 145 to 185 ° C was obtained. This heavy aromatic fraction was mixed with a light aromatic fraction containing 1.8 0.5 5.6 37.2 34.3 20.4 37.3. - 0.1 4.3 24.7 3.2 51.2% toluene and 48.2 wt. 2: 1. The base was converted to the same catalyst as in Example 1, at 410 ° C, 2.0 MPa, 2.5 hr -1, and hydrogen: crude molar ratio. at 10: 1. The composition of the feedstock and liquid reaction products is shown in Table 3. Table 3Composition (w / w) NARA.BE TO CeA nPB 2JET0 2JTMB Cio + A Raw 13.5 - Products 5.0 7.8 Example 4 From Products The transalkylation of the C9 aromatic of Example 1 was followed by distillation of a boiling point boiling range of 55 to 115 ° C, representing the recycle of the Cza Ce aromatics from the process. This fraction contained 26.1. benzene, 64.6% toluene and 9.3% non-aromatic C6-Ce. From the C9aromatic fraction 21.7 0.9 3.4 25.6 29.8 5.1 28.6 38.3 - 2.0 17.3 1.0 varudo distillation fraction 188 ° C, and mixed with the recycle in a 2: 1 weight ratio. This mixture was converted in the same manner as in Example 1, at 420 ° C, 2.5 MPa, 3.0 h -1 and hydrogen: raw material 15: 1. The composition of the raw and liquid reaction products is vtab. 4. Table 4 composition (wt%) nearom.BE TO CeA nPB 2JETO 2JTMB Cio + A raw material 2,9 8,2 products 2,1 10,2 Explanations: BE - benzene TO - toluene CeA - aromatics C8 20,3 1 , 5 4,1 21,7 31,0 10,3 36,5 33,5 - 3,3 13,1 1,2 nPB - n-propylbenzeneIPB - isopropylbenzeneJETO - ethyltoluenes2JTMB - trimethylbenzenesCioA - aromas Cio and above

CLAIMS 1. A process for producing Cearomatic hydrocarbons by converting an aromatic feedstock to a catalyst comprising 0.1 to 15% by weight of at least one of the metals of Group 6 and / or 8 of the Periodic Table, 10 to 80% by weight of zeolite and 20 to 90 % wt. binders, at a temperature of 250 to 520 cc, a pressure of 1.0 to 6.0 MPa, an inventive speed of 0.5 to 8 h ': in the presence of hydrogen or hydrogen containing gas in the hydrogen: molar ratio of 1 to 25: 1 characterized in that the simultaneous trans-alkylation of methylbenzenes, hydrodealkylated higher alkylbenzenes and hydrocracked aromatics is subjected to an aromatic fraction, boiling in the boiling range of 140 to 215 ° C, containing at least 60% by weight, with the source of this aromatic fraction being C9 aromatics from products of catalytic reforming of naphtha and / or isomerization products of Cearomates and / or pyrolysis products, and C9 + aromatic fractions are used in whole or in distillation thereof, preferably between 150 and 195 ° C.

2. Process according to claim 1, characterized in that an aromatic fraction boiling in a boiling range of between 50 and 135 boiling in 10 boiling points is added to the aromatic fraction boiling in the boiling range between 140 and 215 ° C. % C, containing at least 40 wt. C6 and / or C2 aromatic hydrocarbons, in an amount of at most 3 parts of the easier aromatic fraction per part of the aromatic fraction 140 to 215 ° C.

3. Process according to claim 1, characterized in that recyclates of aromatic fractions of Cs and / or C7 and / or C9 + are added to the aromatic fraction boiling in the boiling range between 140 and 215 [deg.] C. from the products of the process. maximum in quantities that correspond to their creation in the process.