DE1083259B - Process for the preparation of cyclooctenones - Google Patents

Description

Process for the preparation of cyclooctenones It has been found that one obtains cyclooctenones if one receives cyclooctanolone- (1,4) and / or cyclooctanolone- (1,5) treated in the presence of dehydrating catalysts at elevated temperature.

The reactions can be represented by the following formulas: Since, as is known, predictions about the mode of reaction of 8-ring compounds are fundamentally impossible, since it is already known from many examples that the 8-ring tends to isomerizations and unforeseeable rearrangements when exposed to high temperatures or different reagents, it was surprising that with the present processes at elevated temperature and under the action of dehydrating catalysts, a completely uniform reaction method was found, which leads to the valuable new unsaturated 8-ring ketones, which represent a new valuable group of substances due to their constitution. This new, simple way could only be developed through the use of the new cyclooctanolones as starting materials.

The starting materials for the process can be cyclooctanolone- (1,4) and / or Cyclooctanolon- (l, 5) use, for example, according to Patent 1029 368 can be obtained in the oxidation of cyclooctane with molecular oxygen, if the residues are removed after the cyclooctanol and cyclooctanone have been distilled off the resulting oxidation mixture is stirred with water and the 1,4- and 1,5-cyclooctanolone from the aqueous layer, e.g. B. by salting out, isolated as a mixture. The mixture can be separated into the two components if you get it with the same volume a hydrocarbon fraction boiling up to about 200 ° C and the dissolved 1,4-Cyclooctanolone after separating off the undissolved 1,5-cyclooctanolone the hydrocarbon solution wins through evaporation.

The two new compounds can, if desired, e.g. B. by Recrystallization, to be further purified.

Another way of obtaining the cyclooctanolone- (1,4) is the catalytic one Dehydrogenation of cyclooctanediol- (1,4) under mild reaction conditions at temperatures ratures around 150 to 2000 C. The new starting materials can be used either as a mixture or individually be implemented by the process according to the invention.

The elimination of water is generally carried out at an elevated temperature at 150 to 400 "C, preferably at 200 to 300 ° C, and expediently below normal or reduced pressure, e.g. B. at 300 to 400 mm Hg executed.

The usual dehydrating catalysts are used such as acids, acid salts or ansolvo acids, e.g. B. phosphoric acid, silica, sodium or potassium bisulfate, the salts of phosphoric acid, anhydrous boric acid and primary, secondary and tertiary boron phosphates, alumina, concentrated sulfuric acid, zinc chloride and oxalic acid. The catalysts can be applied by themselves or on suitable supports be used. Suitable carriers are e.g. B. activated carbon, silica gel and pumice stone.

The reaction can be carried out in the presence of suitable solvents or Diluents, e.g. B. hydrocarbons such as toluene, xylene and cyclooctane, in which the catalysts can be dissolved or suspended, are carried out.

The elimination of water can both in the gas phase with fixed Catalyst as well as in the liquid phase, e.g. B. in the trickle process or in the sump phase, are executed. It is preferable to work in the gas phase, the starting materials, z. B. Cyclooctanolon- (1,4) and / or Cyclooctanolon- (1,5), melted in a burette and then dripped into an evaporator. The vapors of the raw materials can be carried out by a carrier gas, e.g. B. nitrogen or hydrocarbons, via the Lead catalyst.

When working in the sump phase, you can use the dehydrating Catalysts in the melted Suspend starting materials or dissolve and heat them, advantageously while stirring at the same time. In the continuous implementation of the sump phase process, it is advantageous to the resulting Cyclooctenones continuously to be distilled off from the reaction vessel and at the same time the same Add amount of fresh starting materials to the reaction vessel.

In the trickle process, it is advantageous to start with the starting materials to be heated in a preheater before being transferred to a gerigneten reaction tower the fixed catalyst can be trickled.

The reaction product obtained consists of an organic and an aqueous phase. The aqueous layer can be, for. B. by decanting, separate and win the cyclooctenones from the organic phase by distillation. It it is advantageous to remove the organic phase prior to distillation, e.g. B. by water washing, to clean. After a short forerun, the distillation gives a colorless one Liquid that can be identified as pure cyclooctenone. If you use as the starting material cyclooctanolone (1.5) with a melting point of 99 to 1000 C, in this way, 82 to 84 ° C. are obtained on distillation of the reaction product at b.p. pure cycloocten- (4) -one; from cyclooctanolone- (1,4) with a melting point of 58 Up to 59 ° C, pure cycloocten- (3) -one is obtained in the same way at Kr.16 86 to 87 ° C.

The Cyclooctenones, of which only the Cycloocten- (3) -one, called Granatal, from Ber. German Chem.

Ges., Vol. 26, 1893, p. 2738, and Vol. 44, 1911, p. 3423, is known, can be converted into pharmaceuticals by carbonylation, which are Distinguish the effect of increasing bile flow.

The parts mentioned in the examples are parts by weight.

Example 1 100 parts of cyclooctanolone- (1.5) from melting point 99 to 100 "C, which was obtained according to the example of patent 1,029,368, becomes 110 Divide sodium bisulfate slowly to 200 bis in a flask with a descending condenser 210 "C. The resulting mixture of water and cyclooctenone distilled during 3 hours about. The distillate is taken up in ether and separated from the water of reaction and washed with water.

The ether layer is separated off and dried over sodium sulfate. After the ether has been distilled off, 84 parts of crude cycloocten- (4) -one remain, from the 72 parts of pure cycloocten- (4) -one by fractionation of bp 2086 to 880 C. The yield is 83010 of theory.

Example 2 An electrically heated, vertical reaction furnace is filled with a silica-phosphoric acid catalyst in the form of 6 mm strands. - Above the furnace is equipped with an evaporator. 50 parts / hour cyclooctanolone- (1.5) from a melting point of 99 to 1000 C are made from a burette in a molten state put in the evaporator, evaporated at 2500 C, passed into the upper part of the furnace and passed over the catalyst at 2500 C. The reaction product is from the lower Part of the furnace removed and collected in a separator. After the separation of the water becomes the thin organic phase, which is still dark in color, washed with water. After the water has been separated off, it is dried over sodium sulfate and distilled. 2660 parts are obtained from the product collected in 70 hours pure, colorless cycloocten- (4) -one of Bp.11 82 to 84 "C. This yield corresponds to 8701, the theory.

Example 3 100 parts of cyclooctanolone- (1,4) from melting point 58 to 59 "C with 100 parts of potassium bisulfate in a flask with a descending condenser slowly heated to 240C. The resulting mixture of water and cycloocten- (3) -one distilled over within 2 hours, leaving a black residue in the flask remain. The distillate is absorbed in ether, the ethereal layer with water washed neutral and dried over sodium sulfate. After distilling off the Ether remains 61 parts of a crude product, from which one can by fractionation at Kr.16 86 to 87 "C 54 parts of pure cycloocten- (3) -one are obtained. Yield corresponds 6201o the theory.

Example 4 As described in Example 2, 50 parts per hour Cyclooctanolone- (1,4) (melting point 58 to 59 ° C) implemented. The starting material is evaporated at 2200 C and passed over the catalyst at 2500 C by means of nitrogen. The reaction product is worked up as described in Example 2. You get from the discharge of 1550 parts of 1230 parts of pure cycloocten- (3) -one collected in 36 hours from Kr.16 86 to 870 C. That corresponds to a yield of 7801, the theory.

Claims (1)

PATENT CLAIM: Process for the preparation of cyclooctenones, thereby characterized in that one cyclooctanolone (1> 4) and / or cyclooctanolone (1.5) in a known manner with dehydrating catalysts at elevated temperature treated. References considered: J. Am. Chem. Soc., Vol. 61, 1939, 5. 1957 to 1961; Vol. 76, 1954, pp. 3628 to 3630; Vol. 77, 1955, pp.5423 and 5424. Helv. Chim. Acta, Vol. XXXV, 1952, pp. 1598 to 1615.