DE1193040B - Process for the production of cyclohexanone - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

C07c

German class: 12 ο - 25

Number: 1193 040

File number: J19561IV b / 12 ο

Filing date: March 9, 1961

Open date: May 20, 1965

In the purification of cyclohexanone obtained by dehydrogenation of cyclohexanol by distillation falls from a distillation residue of higher-boiling condensation products, the consists mainly of Cyclöhexenylcyclohexanone. This binuclear by-product is commonly split into cyclohexanone by hydrolysis for economic reasons.

This hydrolysis was previously carried out by means of "aqueous inorganic and organic acids or aqueous Alkalis carried out These processes have the disadvantage that the hydrolysis catalyzing substances can only be partially regenerated and only with considerable expenditure of energy.

By the process of German patent 875 512 while cyclohexanone is obtained with a yield of 37 ° / ₀ of theory. According to the example of German patent specification 932 966 , 300 g of 91% pure cyclohexanone are obtained from 400 g of cyclohexenylcyclohexanone, with complete consumption of the starting product used, in addition to 100 g of a resinified residue, corresponding to a yield of 62%, calculated on the converted starting product. In contrast, the present invention relates to a process in which yields well over 70%, based on the converted starting product, are obtained and, moreover, the unconverted starting product is recovered and can therefore be recycled.

It has now been found that Cyclöhexenylcyclohexanon can be cleaved by hydrolysis with water in the presence of acidic medium at temperatures of about 100 ⁰ C advantageously, by acidic hydrolysis agent as strongly acidic sulfonated cation exchangers based on polystyrene used.

This process has the advantage over the previously known that the hydrolysis catalyst serving acidic cation exchanger is not changed and does not have to be regenerated. In addition, the yields of cyclohexanone are also higher than, for example, in the German process Patents 875 512 and 932 966.

The process according to the invention can be carried out batchwise by in an autoclave the cyclöhexenylcyclohexanone is heated together with water and the acidic cation exchanger will. The cyclohexanone is then released together with steam and not converted Cyclöhexenylcyclohexanon removed from the reaction space and the mixture through Extraction and distillation broken down in a known manner. A continuous working method should be according to the procedure for the production of cyclohexanone

Applicant:

Inventa A. G. for research

and patent exploitation, Lucerne (Switzerland)

Representative:

Dr.-Ing. Dr. jur. H. Mediger, patent attorney,

Munich 9, Aggensteinstr. 13th

Named as inventor:

Dr. Alfred Flam, Chur (Switzerland);

Dr. Kurt Kahr, Hambach (a. D. Weinstrasse)

Claimed priority:

Switzerland of March 10, 1960 (2697)

are explained in more detail on the basis of the figure. Into the column 2 with the ion exchanger is filled and the one consisting of the jacket 4, the inlet pipe 8 and the outlet pipe 7 Steam heater is provided, is introduced through line 1 and cyclöhexenylcyclohexanone sprayed through the nozzle 3 in the ion exchanger.

At the same time, water vapor is blown into the column through the line 5 and the nozzle 6. On the ion exchanger the Cyclöhexenylcyclohexanone is partially in the presence of water to cyclohexanone split. This cyclohexanone leaves together with the unreacted starting product and water vapor the column 2 through the line 8 and reaches the cooler 9, where the gaseous mixture condenses will. The condensate is passed through the line 10 into the water separator 11, where the water from the cyclohexanone-cyclohexenylcyclohexanone mixture is separated. The ketone mixture runs from the separator into the distillation column 13, where there is one is subjected to fractional distillation. The gaseous cyclohexanone leaves the column through line 14, is condensed in cooler 15 and can be removed through line 16 while the higher-boiling cyclohexenylcyclohexanone is returned to feed line 1 via line 17.

As strongly acidic sulfonated and crosslinked synthetic resins based on polystyrene z. B. the heat-resistant Commercial products such as "Amberlite JR-120", "Dowex 50" and "Permutit RS" can be used.

509 570/431

The reaction temperature should be 100 ⁰ C because below is of 100 ° C, the reaction rate is too small more. An upper temperature limit is given by the limited thermal stability of the ion exchangers. The abovementioned exchangers are advantageously used at temperatures from 105 to 130.degree.

example 1

100 g of cyclohexenylcyclohexanone are injected into a tube heated to 105 ° C. and activated with 295 g of activated cation exchanger "Amberlite JR-120" (sulfonated, crosslinked polystyrene resin) at three quarters of a height for 100 minutes, while at the same time into the lower part of the tube steam heated to 105 ° C is blown in. After the addition has ended, steam continues to be blown through for a quarter of an hour. The steam consumed corresponds to an amount of water of 4000 cm ³ . The vapor mixture emerging from the upper end of the tube is condensed, the condensate is saturated with sodium chloride and extracted with methylene chloride. 30.8 g of unreacted cyclohexenylcyclohexanone and 55.1 g of cyclohexanone are obtained from the extract by distillation. This corresponds to a yield of 72.3%, based on the converted starting product.

Example 2

300 g of activated cation exchanger “Permutit RS” are placed in the reaction tube 2 of the apparatus described above and shown in the figure for a continuous mode of operation. The tube is heated to 115 ⁰ C. 60 g of cyclohexenylcyclohexanone per hour are introduced through line 1 and at the same time 180 g of steam heated to 115 ° C. per hour are blown in through line 5. The reaction gases are condensed in the cooler 9, the water is separated from the condensate in the separator 11 and the organic phase is fractionated in the column 13

ίο distilled. Every hour this becomes out of the swamp Distillation column 10.8 g of cyclohexenylcyclohexanone via lines 17 and 1 into reaction tube 2 returned. At the same time, 38.1 g of cyclohexanone can be withdrawn from the cooler 15, which is a Yield of 70.5%, based on converted starting material.

Claims (2)

Patent claims: 1. Process for the production of cyclohexanone by hydrolytic cleavage of cyclohexenylcyclohexanone with water in the presence of an acidic agent at temperatures above 100 ° C, characterized in that the acidic hydrolysis agent is strongly acidic sulfonated he cation exchanger based on polystyrene is used. 2. The method according to claim 1, characterized in that temperatures of 105 to 130 ⁰ C are used. Considered publications:
German patent specifications No. 875 512, 932 966. 1 sheet of drawings 509 570/431 5.65 © Bundesdruckerei Berlin