CS253436B1 - Spfisab production of flkenes, alkadienes and their derivatives of alkyne hydrogenates - Google Patents

Abstract

A method for the selective hydrogenation of alkynes and their derivatives to the corresponding alkadienes and alkenes at a temperature of 0 — 20 °C at normal or only slightly elevated pressure in the presence of a solvent and palladium chloride as a catalyst and pyridine bases, preferably quinoline as a hydrogenation deactivator, is described.

Description

The invention relates to a process for the production of alkenes, alkadienes and their derivatives by selective hydrogenation of the respective alkynes.

The selective hydrogenation of 3,7-dimethyl-6-octen-1-yn-3-ol (dehydrolinalol] to 3,7-dimethyl-1,6-octadien-3-ol (linalool) is known. It is carried out on palladium Lindlar catalysts. of the liquid phase, at low temperatures under low hydrogen pressure, i.e. a low rate of hydrogenation, in order not to pre-hydrogenate the double bond to the corresponding alkane.

Basic information about the application of Pd catalyst supported on ^one type of calcium carbonate in the presence of lead salts such dezaktlvátorov described (H. Lindlar: Helv. Ichi. Acta 35, 446/1952 /).

According to the above information, it is recommended to adjust the selectivity of hydrogenation by nitrogenous bases, e.g. quinoline. Despite these known data, another method of selectively) hydrogenating acetylenic bonds (Distlllers Co. Ltd. English Pat. No. 888 999), including the catalyst, is protected. In this process, dehydrolinalool is selectively hydrogenated in 30 wt. isopropanol solution. After hydrogenation at 20 ° C, 97.5% linalool was obtained from 98% dehydrolinalol. The protected catalyst is also deactivated by the lead salt (lead acetate). Furthermore, it is recommended to hydrogenate (NSR Pat. 1 115 238) in the cyclohexane solution also to Pd, by deactivating it with zinc acetate and in the presence of pyridine. The temperature of hydrogenation is 10 to 20 ^C C

In each known case of this type, calcium carbonate, rarely barium, is used as the catalyst support (Tal. Pat. No. 692,799).

Further information (English Pat. 810 913) also protects this method of hydrogenation on a Pd / CaCO3 catalyst in the deactivation of lead-quinoline. To increase selectivity, reduce catalyst consumption, the application of quinoline is emphasized. A hydrogen pressure of 101.3 kPa is used in all cases.

Despite the commonly used method of hydrogenating acetylenic carbinols on a Lindlar type catalyst, this method is difficult due to frequent catalyst deactivation, moreover, the need to completely remove the toxic lead salts from the product and to ensure that they do not reach wastewater and contaminate the intermediates and products.

The present invention provides a process for the production of alkenes, alkadienes and derivatives thereof, preferably 3,7-dimethyl-1,6-octadien-3-ol, by selective hydrogenation of the alkynes in the liquid phase on a palladium metal at temperatures of -20 to 50 ° C, with preferably 0 to 20 ° C, at a nominal or slightly elevated pressure at which the selective hydrogenation by hydrogen and / or hydrogen-containing gas, preferably in the presence of a solvent, is carried out in the presence of palladium halides and pyridine bases, preferably quinoline, is formed "in situ" directly in the reaction system, palladium and products are isolated from the reaction mixture by rectification.

Hydrogenated substrates are substances containing in the molecule acetylenic bond, double bonds conjugated or unconjugated and other functional groups (aryl, halogen, hydroxy, keto).

The catalyst used for this process is preferably palladium (II) chloride, which is in situ reduced by hydrogen. Deactivating bases are added liquid to the reaction medium. Optimally, C6 to C12 hydrocarbons are used as solvents in hydrogenation.

The advantage of hydrogenation according to the present invention is high selectivity, with high selectivity of the catalyst in the process of hydrogenating the triple bond of alkynes, alkadiene alkene and other derivatives. An important advantage of this process of hydrogenation is the simple preparation of the catalyst which is formed "in situ" in the reaction system without the use of reducing components in the liquid state. Further advantages are evident from the exemplary embodiments.

Example 1

A 0.001 part (w / w) palladium (II) chloride and 3.853 parts (30 wt. 3,7-dimethyl-6-octen-1-yn-3-ol (dehydrolinalool), 0.5% w / w; quinoline and the remainder being solvent decane. The entire apparatus is evacuated five times and purged five times with hydrogen after evacuation. After warming to 0 ° C, the actual measurement is started. The overpressure is maintained at a constant nitrogen pressure and maintained at 5 kPa. According to the hydrogen uptake rate, the completion of the selective hydrogenation of the acetylene group to the olefinic group is monitored. After hydrogenation of the triple bond to the double bond, the rate of hydrogen consumption was reduced 10-fold. After the palladium is filtered off, the product is analyzed. The total conversion of dehydrolinalool is 100 percent; selectivity to linalool 98.9% and selectivity to dihydrolinalool 1.2%. Example 2

The procedure is the same as in Example 1 except that hexane is used as the solvent. The conversion of dehydrolinalool is 100%, the selectivity to linalool 98.4%, and the selectivity to dihydrolinalool 1.6 percent.

EXAMPLE 1 a d 3

The procedure is the same as in Example 1, except that isopropyl alcohol is used as the solvent. The conversion of dehydrolinalool is 100%, the selectivity to linalool 97.7% and the selectivity to dihydrolinalool 2.3%.

Example 4

The procedure was carried out in the same manner as in Example 1, except that the hydrogenation mixture contained 0.1 wt. quinoline. The hydrogenation rate of the triple bond was reduced (the reaction was completed in 3 hours in Annex 1, in 4 hours in Annex 4). Conversion 100%, selectivity to linalool 98.9% and selectivity to dihydrolinalool 1.1%.

Example 5

The procedure is as in Example 1, at a temperature of 15 ° C. The reaction was complete in 2 hours. The hydrogenation rate of the double bond is reduced 7-fold. Conversion 98.8%, selectivity to linalool 97.7% and selectivity to dihydrolinalool 2.3%.

Example 6

The procedure was carried out in the same manner as in Example 1, except that the hydrogenation mixture contained 0.5 wt. pyridine. Conversion 100%, selectivity to linalool 95.2% and selectivity to dihydrolinalool 4.8%.

Example 1 and d 7

The procedure is the same as in the SUBJECT

Claims (1)

SUBJECT Preparation of olefins, diolefins and derivatives thereof, preferably 3,7-dimethyl-1,6-octadiene-3-ol, selective hydrogenation of alkynes in the liquid phase on the metal Pd at temperatures of 20 to 50 ^Q C, preferably 0 to 20 ° C , at normal or slightly elevated pressure, characterized in that the selective hydrogenation under the action of hydrogen and / or hydrogen of the facing 1, the hydrogenation mixture containing only 30% by weight of the hydrogenation mixture. % Of 3,7-dimethyl-6-octen-1-yn-3-ol and 70 wt. decane. (Reference experiment without partial deactivation with nitrogen bases. Hydrogenation was complete in 6 hours. The hydrogenation rate of the triple and double bonds is the same. Conversion 97%, selectivity to linalool 83.6% and selectivity to dihydrolinalool 15.7% (prehydrogenated to alkane) ). example The procedure was carried out in the same manner as in Example 1, except that the hydrogenation mixture contained 30 wt. % Of 1-octine, 0.5 wt. quinoline and 69.5 wt. decane. Conversion 99.2%, selectivity to 1-octene 97.2% and selectivity to octane 2.8%. Example 9 The procedure was carried out in the same manner as in Example 1, except that the hydrogenation mixture contained 30 wt. 6-Octen-1-in, 0.5 wt. quinoline and 69.5 wt. decane. Conversion 98.5 percent, selectivity to 1,6-octadiene 97.2% and selectivity to 2-octene 1.9%. The gas reaching the gas, preferably in the presence of a solvent, is carried out in the presence of palladium halides and pyridine bases, preferably quinoline, whereby the catalyst is formed in situ in the reaction system, the palladium and the products are isolated by rectification.