CS270181B1 - Process for preparing verbenol and verbenone by oxidizing K-pinene - Google Patents

Abstract

The solution relates to a method for preparing verbenol and verbenone by oxidizing cA-pinene with molecular oxygen at a temperature of 60 to 120 °C and a pressure of 0.01 to 0.5 MPa. The oxidation is catalyzed by a heterogeneous catalyst based on palladium supported on activated carbon in the presence of cobalt, manganese and bismuth compounds as activators, or zinc and cadmium compounds as coactivators. The amount of catalyst, based on <K-pinene, represents 0.01 to 0.1 wt. % Pd relative to <K-pinene, while the catalyst retains its original activity even after multiple uses. The solution can be used in the chemical industry.

Description

EN 270 181 B1 1

The present invention relates to a process for the oxidation of cr-pinene by molecular oxygen in the presence of heterogeneous catalysts.

Increased care for environmental protection requires more use of the stop to combat harmful insects in agriculture, forestry, and warehousing and biological damage control. Nowadays, there has been an overgrowth of some woodland pest, notably spruce bark beetle. A very effective means of catching it is a biological trap - a trap, equipped with a pheromone attractant. The most important component of the pheromone mixture is the terpene alcohol, verbenol, with the active ingredient being S-cis-verbenol.

Both verbenol and verbenone, produced by the oxidation of verbenol, have a pleasant odor and are also used as perfume ingredients in perfumery.

Both verbenone and verbenol contain some raatlines. The isolation procedures are costly and it is preferable to obtain the compounds by oxidizing o-pinene with oxygen, air or inorganic oxidizing agents,

Oxidation of e (-pinene with oxygen at 40 to 100 ° C in the absence of catalyst yields a very complicated reaction mixture (US Pat. No. 2,911,442 and US Pat. No. 2,862,882) containing e (-pinene oxide, verbenol, verbenone, hydroperoxides ( verbenes 1-, myrtenyl- and pinocamyl hydroperoxide), cis- and trans-3-pinene-2-ol, pinocarveol, pinocarvenone, myrtenal and myrtenol. The usefulness of verbenol and verbenone formation can be markedly enhanced by the use of suitable catalysts in the presence of benzaldehyde and cobalt acetate as catalyst in a water environment at 30 and 40 ° C (US Pat. No. 2,911,441), a 20-27% conversion of? -pinene was obtained. up to 40% yield, transverbenol 20-25% yield and verbenone in 14-19 $ yield relative to reacted o (-pinene).

It is also known to use cobalt palmitate as a catalyst in a pyridine environment at temperatures of 60 to 65 ° C. After a reaction time of 24 h and subsequent oxidation of the reaction mixture, the verbenone was recovered in 33% yield (Brit. Pat. No. 2,078,223). A partial reduction of the reaction time from 16 to 18 h can be achieved by initiating the reaction by adding peracetic acid in the sequential addition of catalyst (CSA 215 485).

By oxidation of β-pinene in chlorobenzene, catalyzed by palladium (II) chloride, or by CuO chlor in the presence of lithium, sodium, barium chloride, most preferably lithium, trans-verbenol and verbenone were obtained with 57% selectivity at 24% by weight. version! oC-pinene. In a similar procedure at 80 ° C in a water-organic solvent under the caustic conditions of PdCl 2 -CuCl 3 -HCl, respectively. PdCl 2 -CuCl 4 -HClO 2 is obtained by oxidation of α-pinene with air to obtain verbenone, verbenol, mono- and tricyclic alcohols and ketones.

The oxidation of olefin by inorganic oxidizing agents, e.g., chromium trioxide, PbO2, and manganese dioxide in pyridine, benzene, and ligoin is only of prominent importance. Oxidation with chromium trioxide in acetic acid gave verbenol in 10% yield (Berichte 61, 549). Other solvents include chloroform and tert-butanol. The S-cis-verbenol, the active component of the pheromone, is usually prepared by the multi-stage «<-pinene} synthesis. In the first stage, oc-pinene is oxidized with oxygen or with air to a mixture of oxidation products which are oxidized in chromium sulphate mixture to the so-called crude verbenone in the second stage. From this, the rectification yields a verbenone fraction greater than 90 which is selectively reduced to S-cis-verbenol.

The disadvantages of the above processes are solved by the preparation of verbenol and verbenone by oxidation of α-pinene with molecular oxygen at a temperature of 60 to 120 ° C, a pressure of 0.01 to 0.5 MPa of the presence of a catalyst, the reaction being carried out in the presence of a heterogeneous catalyst at palladium-based charcoal palladium-containing 1 to 20 wt. based on the weight of < The catalyst is activated with compound cyanobalt, manganese and bismuth in a molar ratio to palladium of 2 to 9: optionally also compound and zinc in a molar ratio to palladium of 0.1 to 0.2: 1. 2 CS 270 181 B1

Activators are added to the palladium pd / C catalysts in the form of aqueous solutions or dilute acid solutions, from which the insoluble precipitates are precipitated in the presence of bases. The advantage of the process according to the invention is that it is only operated in an environment (without using a solvent at a relatively low concentration of the catalyst, whereby the catalyst retains the activity after multiple use. Another advantage is that the reaction time is significantly reduced.

The invention is illustrated by the following examples. Example 1

4.5 g of o-pinene and 0.05 g of Pd-Bi-Zn / C catalyst containing 5.4% by weight were weighed into a 50 cnP stainless steel reactor. % Pd, 8.3 wt. Bi and 0.46 wt. Zn. The entire system was suppressed with oxygen, refueled at 0.2 UPa, and the reactor aa placed in an oil bath, heated to 100 ° C for 5 minutes. The start of the reaction was counted from the moment the reactor was shaken, whereupon the reaction mixture was intensively mixed. the oxygen pressure consumed was automatically compensated by pumping the inert liquid, the volume of which, corresponding to the oxygen consumption, was recorded at certain time intervals after conversion to the reactor pressure. After consuming oxygen. the reaction was stopped (54 min) and the content of verbenol, verbenone and unreacted Z-pinene was determined in the reaction mixture after the catalyst had settled by gas-liquid chromatography, the internal standard method. With 31.4% con-version! o (-pinene was obtained verbenone 3 by 24.2% selectivity and verbenol with 58.9% selectivity. Example 2)

To the reactor, as described in Example 1, was weighed 4.5 g of <RTIgt; <<-pinene </RTI> and 0.1 g of Pd-Co-Cd / C catalyst containing 2.86% by weight. % Pd, 1.96 wt. Co and 0.7 wt. CD. At a temperature of 80 ° C and an oxygen pressure of 0.1 UPa, the same operating procedure was followed as in Example 1. At 48.2% conversion! o -pinene was obtained after 50 min by verbenone with 25.1% selectivity and verbenol with 67.8% selectivity. Example 3

220 g of eZ-piene and 1.5 g of Pd-Co-Cd / C catalyst containing 4.86% by weight were weighed into a 550 cnp stainless steel tower reactor. % Pd, 1.96 wt. Co and 0.7 wt. CD. The reactor was heated to 80 ° C by circulating water from the thermostat into the reactor jacket. Oxygen was blown into the bottom of the reactor through a glass frit at a pressure of 0.1 UPa. The pressure reactor was maintained at the desired value by a membrane manometer and the flow rate was maintained at 300 cm min. Samples of the reaction mixture (1-2 cm 3) were taken at certain time intervals using a sampling valve. Prior to sample collection, the capillary was flushed with nitrogen from a pressurized bottle. After 6 h, the reaction was complete and after the catalyst had settled, the reaction product was aspirated from the reactor and the catalyst was used for further oxidation. At 42.4 Ž kon-version! o (-pinene was obtained by verbenone with 28.2% selectivity and verbenol with 57.4% selectivity. After subsequent oxidation of the reaction product with chromosulphuric mixture, verbenone was obtained in 35.5% mole yield.

To the bubbled tower reactor described in Example 3, 220 g of fresh z-pinone was added to the catalyst used in the 4 oxidations. At a temperature of 85 ° C, an oxygen pressure of 0.1 MPa and a flow rate of 180 cm 2 / min, a verbone of 29.3% selectivity and a veronol of 60.6% selectivity on conversion was obtained after 6 h. Z-pinene 40.4% Example 5

To the bubbled tower reactor described in Example 3, 220 g of fresh p-pinene was added to the catalyst used in the 9 oxidations. Verbenone with 29.7% selectivity and verbenol with 58.5% selectivity at 44.4% conversion cZ- pinene.

Claims (2)

OBJECT OF THE INVENTION A process for the preparation of verbenol and verbenone by oxidation of X-pinene with molecular oxygen at a temperature of 60 to 120 ° C, a pressure of 0.01 to 0.5 MPa in the presence of a catalyst, characterized in that a heterogeneous palladium catalyst supported on activated carbon with containing 1 to 20% by weight of palladium based on the weight of the support in an amount of 0.01 to 0.1% by weight based on the weight of <K-pinene, is activated by cobalt, manganese and bismuth compounds in a molar ratio to palladium of 2 to 9: 1. 2. The process according to item 1, characterized in that the catalyst is activated with cadmium or zinc salts in a molar ratio to palladium of 1 to 2: 1.