DE1618266C3 - Process for the preparation of 1,2,4-trimethyl-5-isopropylbenzene - Google Patents

Description

therefore added in portions during the reaction so that there was 1% AlCl ₁ in the reaction vessel.

The amounts of product obtained per hour were worked up together as in Example 1 and by gas chromatography analyzed.

Total yield of 1,2,4-trimethyl-5 (6) -isopropylbenzene 80 (20) after a reaction time of 60 hours: 35.4 kg corresponding to 98.5% of theory.

The advantages achieved with the invention are, in addition to a significant improvement in yield, in that the l, 2,4-trimethyl-5-isopropylbenzene produced in this way is free from durol, isodurol and others Isomerization resulting alkylbenzenes is. If the reaction conditions according to the invention are adhered to the 1,2,4-trimethyl-6-isopropylbenzene content can be reduced to 20% of the reaction product will.

Claims (1)

1 2 The pseidocumene used for the reaction Claim: shot can be varied within wide limits but conveniently around 50%. It can be commercial Process for the preparation of 1,2,4-trimethyl- customary anhydrous aluminum (III) chloride ver-5-isopropylbenzene by alkylating pseudo-5 are used; no special protective measures are necessary to keep the salt dry.
AICIj as a catalyst at temperatures up to 50 ⁰ C, characterized in that Example 1 pseudocumene with 0.5 to 1.2 percent by weight in a stirred vessel that is equipped with an intensive stirrer, AlCl ₃ presented and at temperatures between 15 io a thermometer with l / 10 ° division, up to and 50 ° C 0.17 to 0.25 mole propene / mole pseudo- to the bottom reaching gas line pipe and cooling cumene / hour up to a total amount von Schlangen was equipped, 240 g (2 mol) were introduced about 0.5 mol propene / mol pseudocumene. Submitted pseudocumene and heated to 30.degree. Then 1 percent by weight of AlCl _{3 was} added and the reaction started after the aluminum chloride-aromatic complex had formed. The propene was liquid introduced so that the Feed rate 0.17 moles of propylene per MoI pseudocumene per hour. (It is natural 20 also possible to introduce gaseous propene.) Through The invention relates to a process for producing cooling, the reaction temperature of 30 ⁰ C of l, 2,4-trimethyl-5-isopropylbenzene maintained by alkylene. There was no exhaust gas, the introduced pseudocumene with a deficit of propene was quantitatively implemented.
Propene in the presence of aluminum (III) chloride. The reaction was continued until 42 g (1 mol) The 1,2,4,5-tetraalkylbenzenes are valuable propylene that was introduced. products for the production of pyromellitic acid, after completion of the reaction, after 20 minutes as a raw material, for example for the production of tiger stirring of the liquid catalyst sludge water-soluble paint resins, high temperature resistant separated (the catalyst sludge was separated digen electrical insulating varnishes and hardeners for epoxy refurbished, the organic phase then the raw resin serves. - 3 ° product added), the organic phase with water. It is known that 1,2,4-trimethyl-5-isopropylbenzene is washed neutral and placed in a packed column distilled by alkylation and isomerization of pseudo. ^cumo1 TTm ^Pr u, ^Pen ^ ⁿ K ^Geg _C n ^nW K ^rt Γ. * ^eu £ ^htem ^ ₁ ¹ "" 1st fraction bp. _76omraHg : 168 to 169 ⁰ C 119 g to produce minium (ni) chloride at 80 to 90 C ¹ , _ p _seu documoD · (USA -PatentMhrift 3 132 18?) After this procedure 35 ₂ . ^l p _raction bp _{76 in} H _g : 220 to 222 ° C 160 g;
a mixture of intermediate fraction and residue 3 g results with a total yield of 60%. Tetraalkylbenzenes which, according to the information in the cited publication, consist of about 45% 1,2,4-trimethyl. The 160 g of fraction 2 correspond to 98.8% of 5-isopropylbenzene and about 15% durol. It prey on tetraalkylbenzenes. However, reaction and reaction can be determined by gas chromatography at 4 °. tion products were determined by gas chromatography to show that the production of 1,2,4-trimethyl-100-m-KapillarsäuIe (silicone oil DC 550) was checked (per-5-isopropylbenzene always from the formation of 1,2,4-trinine -Elmer F 6, FiD detector). It was found that methyl-6-isopropylbenzene is accompanied. In the process known from fraction 2 from l ^^ - trimethyl-S-isopropyl, the proportion of 1,2,4-tri-benzene and 1,2,4-trimethyl-6-isopropylbenzene in methyl-6-isopropylbenzene is in the Overall yield consisted of 45 weight ratio 80:20.
Tetraalkylbenzenes about 25%. Also contains. .
the mixture still has about 15% tsodurol. B e 1 s ρ 1 e I 2 According to the method of the French patent specification. 1,460,349 one obtains a mixture of 1,2,4-trimethyl- a thermometer, a 5-isopropylbenzene reaching to the bottom and other trimethylisopropyl- 50 gas inlet pipe and a cooling device for benzene isomers by alkylating pseudocumene to cool the contents of the flask with valve-controlled excess propene Was equipped in the presence of AlCl ₃ and drain, 1200 g (10 mol) as a catalyst, preferably at temperatures of. Pseudocumene presented. At 30 ⁰ C followed by 30 to 50 ° C. 1 weight percent of AlCl ₃ were suspended in pseudocumene The invention is based on the object, the 55 and within 2 hours 1221 (5.08 mol) of propene Yield of 1,2,4-trimethyl-5-isopropylbenzene to be introduced. increase and at the same time the amount and number of Ne- The rate of introduction was 0.25 mol to reduce benproducts. Propene per mole of pseudocumene per hour. Subsequent The method of the invention for making. ßend the feed of pseudocumene and the l, 2,4-trimethyl-5-isopropylbenzene was regulated by alkylation 60 decrease of product (50% pseudocumene + 50% of pseudocumene with propene in the presence of isopropylpseudocumene) so that in the dry AlCl ₃ As a catalyst at reaction vessel temperatures, an average residence time of 2 hours up to 50 ° C. is characterized in that it is obtained. Propene was submitted continuously with a Ge-pseudocumene with 0.5 to 1.2 weight percent AlCl ₃ speed of 0.25 mol propene / mol pseudocumene / and initiated at temperatures between 15 and 50 ° C for 65 hours. The reaction temperature was 0.17 to 0.25 mol propene / mol pseudocumene / hour 30 ° C. up to a total amount of about 0.5 mol of propene / the finely divided catalyst in the reaction vessel Mol pseudocumene initiates. was deducted with the removal and had to