DE1518168A1 - Process for working up C9 aromatic mixtures with simultaneous recovery of toluene, ethylbenzene and cumene - Google Patents

Description

Process for the work-up of C9 aromatic mixtures with simultaneous Obtaining of toluene, ethylbenzene and cumene C9 aromatic fractions, how to get them from Reformathenzinen obtained by extraction and subsequent distillation exist from a large number of components listed in Table 1.

Table 1; Composition of technical C @ aromatic fractions ============================================= ============================ Compound b.p. at% content in the C9 aromatic fraction 760 Terr after ° C (1) (2) (3) (4) ====================================================================== =========================== o-xylene 144.4 5.4 0.6 -4.2 cumene 152.4 2.4 0.5 1.75 n-propyl benzene 159.2 7.1 6.2 9.6 6.75 m-ethyltoluene 161.3 17.4 23.1 18.5 20.2 p-ethyltoluene 162.0 8.9 13.4 8.9 8.1 mesitylene 164.7 8.8 13.1 5.2 7.25 o-ethyltolaal 165.2 8.1 12.2 11.2 6.75 pseudoumoles 169.4 22.8 30.9 26.7 27.3 Ischutylbenzene 172.8 0.2--0.75 sec-butylbenzene 173.3 0.1 - - -m-Isopropyltelnol 175.1 0.9 - - 3.0b) Hemimellitol 176.1 6.2 - 15.3a) 6.5 fital a-IaoBMpyitolOiel177.10,% - Indane 177 1.4 - - 3.1 e-Isoprepyltoluene 178.2 0.1 - - - =========================================================================== ====================== a) including C10 aromatics; b) including p-isopropyltoluene (1) R.B. Williams, S.H. Hastings et al. Anderson Jr., Analytic. C @ em. 24, 1916 (1952) (2) Yes.I. Lejtman, IN. Dijarov and M.S. Pevzner, Erdölchemie (Russian) 2, 242 (1962) (3) K.H. Wingerter, Chem, Techn. 14, 333 (1962) (4) Smeykal, H.G. Hauthal, W. Engler, Chem. Techn. 14, 732 (1962) From don tschalach C9 aromatic mixtures can be n by further distillative Processing fractions are used in which only a few of the compounds listed, possibly in Gamisch aii C8 or C10 aromatics, are also present in the technical production of o-xylene, C9 aromatic mixtures are obtained, which are not contain all of the connections listed in Table 1.

The distillative recovery of the technically particularly interesting Trimethylbenzenes from C9 aromatic fractions is produced by the presence of anthyltoluene and the Osopropyltoluenes very difficult.

It has now been found that C9 aromatic mixtures with simultaneous Extraction of toluene, ethylbenzene and cumel worked up and the disruptive ethyltoluene and isopropyltoluenes can be removed therefrom if these mixtures are in the presence a Friedel-Crafts catalyst treated with benzene and the reaction product subjected to fractional distillation after separation of the catalyst.

Dabes atellaa the equilibria ethyltoluene + benzene # toluene + Ethylbenzene isopropyltoluene + benzene # toluene + cumene a, and it arise from the interfering compounds in the C9 aromatic mixture are valuable and can be separated off Products toluene, ethylbenzene and cumene. The reaction mixture is allowed to settle won the main amount and duroh Auawaechen with 67mazer wom Reat don the catalyst. The preparation by distillation is then the. pure components With this mixture no difficulty is possible.

The reaction rate can be increased when using a mixture as a Cocatalyst an anhydrous hydrogen halide or one under the reaction conditions Hydrogen halide splitting end, in particular an alkyl halide, is added.

The process according to the invention for the preparation of C9 aromatic mixtures is expediently carried out in the temperature range from 0 to 150.degree. The jewcila necessary The reaction times differ mostly from the temperature and from the type and amount of the applied @catalyst. They are generally between 3 and 300 mins.

The Friedel-Crafts catalyst is preferably used in amounts of 2 up to 15% by weight, based on the C9 aromatic mixture. Is particularly suitable the aluminum chloride. The use of boron trifluoride is also advantageous in combination with Fluerwazaer atoff. When using the same Katalyaatoroyateme the Aux et dadorch facilitates that both Katalyeatorkcaponenten at temperatures Above 30oC or can be removed in vapor form using a vacuum.

If hydrogen chloride or hydrogen hydrogen is used as co-catalysts, so these can be used in amounts of up to 1 mol pre 1 mol Friedel Grafts catalyst will. When using boron triflueride as a catalyst in the same amount as Theoretically not limited P to be cocatalyst, de hydrogen fluoride Temperatures below 20 ° C or a liquid phase when using overpressure forms.

The Bensolmengs that can be expediently derived from the C9 aromatic mixture from the equilibrium values of the renctienes determined by us It-hyltolual + Bansoli MOILWI + Xibylboml (X-2, 2) loopropyltolmol + Sonso ft3Luol + Owwlg <K-2. ) which are practically dependent on temperature. In general, the weight ratio of C9 aromatic mixture to benzene is chosen between 1: 0.5 and 1:10.

The method according to the invention for the preparation of C9-Are @@ tengemischen can be carried out batchwise or continuously. With continuous The use of a three- or five-part reactor cascade is recommended, in order to keep the dwell time trends low and thus the undesired transalkylation to suppress the trimethylbene sols.

Example 1: In a three-necked flask of 250 amij Iahalt, which with R is equipped with a reflux condenser and thermometer, an aromatic mixture is added from 30 g m / p-ethyltoluene and 30 g mesitylene, and set 88 g benzene ruz Nit Hilfe in a hot bath with a thermostat, the contents of the flask are reduced to a Bred temperature of 85 ° C. Then 7.5 g of anhydrous aluminum chloride are added in addition, vegetables under good rubane at 85 ° C react at regular intervals about 5 Z3 are taken from the reaction mixture for analysis samples. These will @ Immediately after sampling, treated as follows: Shake twice Amount of distilled water, dry over potassium carbonate and filtered. the Samples cordon finally determined by gas chromatography for their composition. The change in the composition of the aromatic mixture w the duration of the Veraucha Table 2 shows that the numerical data are based on mol%.

Eg 2t in yin 250 liter, inside enamelled agitator 30 kg of m / p-ethyltoluene and 30 kg of paeudoeumol and 88 kg of Bonmol M. Naoh are added Warming to 85 ° C., 7 kg of anhydrous aluminum bromide are added to the mixture.

After a reaction time of 180 minutes, the mixture has the following Composition: Benzene 54.1 Mel-% Toluene 14.2 "EthylbenMl14.0" m / p-lylel1.0 * * -xylene 0.2 "ethyl toluenes 1.5" mesitylene 4.2 "pseudo @ umel 10.8".

The Katalyaator is decomposed by adding 50 liters of water aqueous phase separated and the organic phase at 40 ° C for one hour with Mix 20 kg of finely powdered potassium oxide.

Table 2: Transalkylation of C9 aromatics with benzene ========================================= ================================ Reaction Benzel Toluene Ethylbenzene m / p-Xylene- o-Xylene m / p-Ethy time in toluene Minutes =========================================================================== ====================== 0 69.0 - - - - 15.5 5 68.4 0.5 0.6 - - 15.1 10 67.4 1.6 1.5 - - 13.5 15 66.7 2.7 2.5 - - 11.6 20 65.4 3.5 3.4 - - 11.5 30 62.2 6.4 6.2 0.2 - 9.2 45 60.8 8.1 7.9 0.2 - 7.5 60 57.0 11.2 10.9 0.3 - 5.5 90 56.0 12.6 12.2 0.4 - 3.5 120 55.6 13.1 13.1 0.6 0.1 2.5 180 54.8 14.0 13.8 0.8 0.1 1.5 240 54.4 13.8 13.8 1.0 0.2 1.5 === ============================================================================= ================== To Allowing the solids to settle, the liquid is poured into a still pumped. By distillation, 69 kg of benzene, 21 kg of toluene, 26 kg of ethylenenzene, 93%, 11 kg of mesitylene fraction, 75%, 21 kg of pseudocumene, more than 98%, was obtained.

Example 3; In a three-hand flask with a volume of 250 cm3, which is equipped with a stirrer, The reflux condenser, thermometer and gas inlet tube are used to give 80 g of benzene and 19 g of anhydrous aluminum chloride. The mixture is saturated with dry hydrogen chloride, heated to 80 ° C., 90 g of a C9 aromatic mixture heated to 80 ° C. (composition; 0.5% o-xylene, 3.5% cumene, 6.0% n-propylbenzene, 24.0% m / p-ethyltoluene, 5% o-ethyltoluene, 14.0% Me @ itylene, 39.0% P @ eudocumol, 6.5% Hemimeltitel) see below and IU * the mixture below react with stirring at 80 ° C.

Samples of the reaction mixture are taken at regular intervals } 5 cm3 accepted, processed and analyzed as described in Example 1 will. The change in the composition of the aromatic geaiaohea over the course of time of the experiment can be seen from Table 3, preceded by the numerical data relate to mol%.

3e In sinon three-necked flask of 10 liter capacity, with agitator, If the fluid cooler and thermometer are provided, 2340 g of benzene and 220 g of anhydrous are added Aluminum chloride and 2000 g of a C9 aromatic fraction of the following composition; 3% cumene, 20% n-propylbenzene, 46% @ / p-ethyltoluene, 85% o-ethylteoluene, 6% mesitylone, 16% paeudeeumel and 1% lemimellitol. The mixture is allowed to stir for 180 minutes with good stirring auf) 5CerhitatAfter the reaction has ended, the mterePhMe (545g) is separated from the Gemiaeh, which connects an additionof @ represents aluminum chloride and aromatics. The addition connection can be used for other Reactions are used as a catalyst. The upper Table 3: Re-alkylation of C9-Arommton with Bensol =========================================== ============================ React.- Ben- To- ethyl- m / p- o- cumene n- m / p- o-time zol l @@ l benzene xylene xylene Propyl Ethyl Eth in benzene toluene @ol Minmten ======================================= ================================= 0 58.0 - - - 0.2 1.5 2.5 10.0 2.5 56.4 1.5 1.4 - 0.2 1.5 2.5 8.7 2, 10 55.4 3.2 3.0 - 0.2 1.5 2.5 7.2 2.15 51.6 6.2 6.0 - 0.2 1.5 2.5 5.0 1.20 50.5 7.0 7.0 0.1 0.2 1.5 2.5 4.7 1.30 49.6 9.0 8.8 0.2 0.1 1.5 2.5 2.5 0.45 49.2 9.5 9. 5 0.2 0.1 1.5 2.5 1.7 0.5 60 487.7 10.5 10.3 0.2 0.1 1.5 2.5 1.0 0.75 48.6 10.4 10.4 0 , 3 0.1 1.5 2.5 1.0 0.90 48.9 10.2 10.4 0.4 01, 1.5 2.5 1.0 0.120 48.5 10.1 10.4 0.6 0.1 1.5 2.5 1.0 0. ------------------------------------ --------------------------------- phase becomes ait 2 liters of agear, 2 liters of 5% aqueous soda long and again with the shaken out the same amount of water and dried with t. The purified mixture (4606 g) is attached to a vacuum jacket 1 m long with wire coils from the Measuring eyes 2 x 2 mm is filled, distilled with a reflux ratio of 20: 1.

The following praction has been obtained: 1795 g of benzene.

655 g teluene, 735 g ethylbenzene, 60 g cumene, 390 g n-propylbenzene, 410 g of 94.8% trimethylbenzene.

Example 5; 420 are placed in a 2 liter stirrer autoclave g benzene, 360 g of a C9 aromatic mixture (composition; 3% cumene, 20% n-propylbenzene, 54% ethyl toluene, 6% mesitylene, 16% pseudecumel, 1% top), 360 g anhydrous fluorine and 36 g of bertrifluoride. The mixture is heated to 40 ° C and the products are left together for 2 hours react. Then the Antorklev is slowly relaxed, using hydrogen fluoride and Boron trifluoride escape in gaseous form. Both products are caught in a cold trap. To completely remove hydrogen fluoride and boron triflueride, 1 bead is used A gentle stream of nitrogen through the reaction mixture for 1 hour. Num will the autoclave is cooled and emptied. The reaction mixture becomes a fractionated Subjected to distillation, the following fractions being obtained: 320 g Basol, 125 g 140 g ethylbenzene, 15 g cumene, 75 g n-propylbenzene, 80 g 96% vox trimethylkenzene.

Example 6 The transalkylation is carried out in a reactor cascade. D @ REaktorkaskade consists of three glass tubes, each 40 cm long and 6 cm in diameter. The lower end of the first reaction column is connected to a metering pump. In the upper part there is an outlet for the reaction product, which is lower in the dam Zends doa second pipe roa f The same way are the second and third pipe @@ connected to each other. At the top of the third tube, the product leaves the Appa rature. The connecting pipes between the individual pipes are ardaet in this way that 1 liter of reaction product is present in each of these.

The entire apparatus is in a heated to 805C Bath.

Dural addition of 150 g of anhydrous aluminum chloride to 300 @ e heated C9 aromatic mixture, a catalyst mixture is produced and one third of each this mixture is added to the individual reactions br. Dansch becomes with the help of the Dosing pump 1 liter pre Stune oin Qemiaohea, daa in equal parts by weight a C9 aromatic fraction and benzene, pumped into the reaction cascade (composition the aromatic fraction: 3% cumene, 20% n-propylbenzene, 46% m / p-ethylteluene, 8% o-ethyltolnol, 6% mesitylene, 16% pseudo @ umel, 1% hemimelitel). The one that leaves the reaction cascade The product is mixed with the same volume of water and 5% aqueous sodium hydroxide solution and washed again with water and 20 kg of the purified over caloium chloride getro a Product are in a column with 30 theoretical plates and a bubble content of 40 liters distilled. The following fratcones are obtained: 6570 g of benzene 4020 g teoluene 4455 g ethylbenzene 295 g Caml 2050 g n-propylbenzel 2400 95.5% Trimethylbenzene.

The trimethylbenzene contains 35.5% mesitylene, 50% p @ eudocumel ans to 9 Homimlliiolo

Claims (6)

Claims: 1. Process for working up C9 aromatic mixtures with simultaneous recovery of toluene, ethylbenzel and cumene, characterized in that that the mixtures are treated in the presence of a Priedel-Craftz catalyst ait benzene and the reaction product after separation of the catalyst of a fractionated Subjects to distillation. 2. Verfahron according to Anspraoh 1, characterized in that the reaction agemisoh as cocatalyst an anhydrous halogenated water or one under the reaction conditions Eliminate hydrogen halide compound, in particular an alkyl halide was added will. 3. The method according to claim 1 and 2, characterized in that the Reaction is carried out at temperatures between 0 ° and 150'00. 4. The method according to claim 1 to 39, characterized in that da8 ale Friedel-Crafte catalyst aluminum chloride and, as hydrogen halide, hydrogen chloride be used. 5. The method according to claim 1 to 3, characterized daduroh that as Friedel-Crafts catalyst bertrifluoride and, as halogenated hydrogen, hydrogen fluoride be used. 6. The method according to claim 1 to 5, characterized in that aB dan Weight @ ratio of the above C9 aromatic mixture to benzene selected between 1: 0.5 and 1:10 will.