CS273820B1 - Treatment of bottomsfrom cyclohexanone - Google Patents

Abstract

The invention concerns a method of treatment of liquid resides from refining distillation of a cyclohexanone-cyclohexanol mixture occurring during catalytic oxidation of cyclohexanone. The essence of the invention is that these residues are heated with 0.5 to 5 % alkaline hydroxide to up to 260 degrees C while introducing water vapour at a pressure of 0.2 to 2 MPa with simultaneous distillation off of the shares boiling up to 260 degrees C through the distillation column. The heated organic phase is then separated by distillation under atmospheric or reduced pressure.

Description

(57) It addresses a process for the treatment of liquid residues from the refinery distillation of a cyclohexanone-cyclohexanol mixture resulting from the catalytic oxidation of cyclohexanone. The essence of the solution is that these residues are heated with 0.5 to 5% alkali hydroxide to a temperature of up to 260 ° C by introducing superheated water vapor at a pressure of 0.2 to 2 MPa while distilling off portions boiling up to 260 ° C through the distillation. column. The superheated organic phase is then separated by distillation at atmospheric or reduced pressure.

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CS 273 820 81

The invention solves the treatment of liquid residues from the refinery distillation of the cyclohexanone-cyclohexanol mixture resulting from the catalytic oxidation of cyclohexane.

In the production of cyclohexanone by catalytic oxidation of cyclohexane, a number of waste products arise from both the oxidation processes and the condensation reactions of the individual intermediates. Waste products containing acid, ester and lactone compounds can be processed to the corresponding acids and their esters. It is also known to treat wastes containing a mixture of alcohols. When rectifying the cyclohexanone-cyclohexanol mixture on the last rectification columns, unpleasantly odorous liquid residues, which are virtually neutral and free of carboxylic acid derivatives, are eliminated. These distillates contain 1 to 5% cyclohexanone, 1 to 10% cyclohexanol, 12 to 15% dicyclohexyl ether, 30 to 50% differently hydrogenated diphenyl ethers and biphenyls, 30 to 35% 2- (1-cyclohexenyl) cyclohexanone and about 5% unidentified, strongly odorous substances. Thus, it is a raw material containing a large number of otherwise difficult to obtain, differently hydrogenated diphenyl ethers and biphenyls, suitable as diluents and plasticizers for epoxy resins and as coalescents of polymer dispersions. However, a simple distillation separation, even on the most efficient columns, does not allow the removal of the penetrant odor products derived from 2- (1-cyclohexenyl) cyclohexanone and other unidentified substances. Therefore, these wastes are still disposed of by incineration. The literature describes a process for treating these wastes by hydrogenation to cyclohexane and methylcyclopentane (German Pat. No. 2,111,439). Furthermore, the use of waste products from cyclohexanone production as epoxy resin diluents (cf. No. 230 225) and as plasticizers (cf. No. 230 799) has been described. The direct use of the distillation residues from cyclohexanone production for this purpose is only possible in the production from phenol by hydrogenation and dehydrogenation, while in the production by oxidation of cyclohexane the direct use of the distillation residues is prevented by a penetrating and unpleasant odor.

It has been known that 2- (1-cyclohexenyl) cyclohexanone-di-nuclear cycloaliphatic ketones themselves can be hydrolytically cleaved at elevated temperature and pressure (German Pat. No. 927,888,

946 443) or, at atmospheric pressure, in admixture with less than 5% water (Brit. Pat. 1 086 077) or with more than 12% water (US Pat. 95 459).

We have worked out a process for processing said wastes into technically useful products, in particular dicyclohexyl ether, various hydrogenated products of diphenyl ethers and biphenyl and cyclohexanone. The process consists of introducing superheated water vapor at a pressure of 0.2 to 2 MPa in the presence of 0.5 to 5% alkaline hydroxide at a temperature of up to 260 ° C and simultaneously distilling off portions boiling up to 260 ° C through a distillation column. ° C, then the excess organic phase is separated by distillation at atmospheric or reduced pressure. In this alkaline refining with the introduction of superheated water vapor, the intensely odorous binuclear ketones are cleaved to cyclohexanone and the resulting organic phase exaggerated by water vapor is readily separable by distillation. The use of a distillation column prevents the entrainment of the dinuclear cycloaliphatic ketones before they are cleaved to cyclohexanone. The distillation column used should have at least two theoretical plates.

Fractionation of the organic phase pe yields a cyclohexanone fraction containing 60 to 85% cyclohexanone, mainly accompanied by cyclohexanol. The dicyclohexyl ether fraction has a concentration of 50 to 90% and contains various hydrogenated diphenyl ethers and biphenyls as accompanying substances. It is a colorless liquid, a faint camphorous odor boiling in the range of 225 to 255 ° C, suitable as a high-boiling solvent and coalescent.

Of the possible alkali hydroxides, sodium hydroxide is preferably the alkali, either in a pellet form or in an aqueous solution having a concentration of 30 to 50%. The optimum steam pressure is 0.4 to 1.2 MPa, the optimum batch temperature 160 to 240 ° C. The water vapor residue is a brown-black mass, solid at normal temperature, soluble in hydrocarbons.

The superheated steam can be subjected to the whole of the liquid residue resulting from the refining distillation of the cyclohexanone-cyclohexanol mixture or its individual fractions. .

CS 273 820 B1 2

The invention is further illustrated by the following non-limiting examples.

Example 1

The distillation residue from the final rectification of the cyclohexanene-cyclohexanol mixture from cyclohexanone production catalyzed by cyclohexane oxidation was a brown liquid of a sharp pungent, refractive index at 20 ° C 1.4860, viscosity at 20 ° C 9 mPa.s, density at 20 ° C 969 kg .m ³ .

000 g of this residue was heated at atmospheric pressure with 40 g of sodium hydroxide under a descending condenser distillation column. After reaching a temperature of 80 ^Q C was placed into the batch water vapor at a pressure of 0.4 MPa until the batch temperature had reached 240 ° C and a refractive index of the flowing fraction of 1.4930 at 20 ° C. A total of 1,445 g of an organic phase having a refractive index at 20 ° C of 1.4595 distilled. The residual dark brown color was 588 g.

The organic phase was distilled through the column first under atmospheric, then under reduced pressure.

Fractions the boiling point pressure amount refractive index C. Noc: 2 ° C kPa G at 20 ° C 1 do 155 101 121.5 1.4327 2 155 to 165 101 642.8 1,4525 3 165 to 219 101 135.5 1.4612 4 to 115 2.67 75.0 1.4615 5 115 to 125 2.67 280.7 1.4719 residue 185.5 1,4888

Fraction 1 has a sharp odor and is suitable as fuel oil. Fraction 2 is a mixture of cyclohexanone and cyclohexanol. Fractions 3 and 4 are intermediate fractions containing both cyclohexanone and dicyclic hexyl ether. Fraction 5 is a technical dicyclohexyl ether of 80% concentration, which contains various hydrogenated biphenyls and diphenyl ethers as accompanying substances. The rest is a brownish, clear liquid.

Example 2

Of the 2,000 g of the distillation residue of the same quality as in Example 1, 1,379 g of a yellowish liquid were distilled off at 90 to 150 ° C at a pressure of 2.67 kPa. The brownish residue having a viscosity of 26.2 mPa · s at 20 ° C is suitable as a saponification softener for polyA styrene paints.

To 1379 g of distillate was added 55 g of 50¾ aqueous sodium hydroxide solution and the mixture was heated under a descending condenser distillation column. After reaching a temperature of 100 ° C, steam was introduced into the batch at a pressure of 0.8 MPa until the temperature of the batch rose to 240 ° C and the organic phase ceased to pass with water. 1 042 g of an organic, slightly yellow colored phase was obtained which was distilled through the column.

Fractions the boiling point pressure amount refractive index C. Noc: 2 ° C kPa G at 20 ° C 1 do 155 101 69.4 1.4390 2 155 to 165 101 310.5 1,4535 3 165 to 220 101 139.0 1,4635 residue 519.0 1.4770

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CS 273 820 01

The residue of a light yellow color has a viscosity at 20 ° C of 5.36 mPa · s and is a good diluent and plasticizer for epoxy resins.

Claims (2)

PREVENTION OF THE INVENTION Process for the treatment of liquid residues from the refinery distillation of a cyclohexanone-cyclohexanol mixture, produced by catalytic oxidation of cyclohexanone, by heating in the presence of alkali hydroxide and water, characterized in that superheated steam at pressures of 0.2 to 2 MPa to distill off portions boiling up to 260 ° C, then the excess organic phase is separated by distillation at atmospheric or reduced pressure.