CS252376B1 - Method of lindlar catalyst selectivation - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

CH 1 m ₃

Indispensable in the production of vitamin A by the Isler process or for the partial hydrogeination of 3,7-trimethyl-6-octen-1-in-3-ol, hereinafter referred to as dehydrolinalool of formula II and its esters of formula III. other fragrances widely used in housing chemistry.

cyclohexen- (1) -yl] -nonadiene- (2,7) -ine- (4J-diol- (1,6J), hereinafter referred to as C 6 -diol of formula I

On) wherein R is an aliphatic residue with a carbon number

C1 to C1.

The industrial partial hydrogenation of the compounds of formulas I, II, III is carried out by low-percentage palladium catalysts, which have the advantage of allowing the process to be carried out under low pressure. Most commonly, a Limdlar catalyst composed of 6% palladium, 6% lead on calcium carbonate or barium sulphate is used (Lndlar H., Helv. Chim. Acta 35, 446,: [1952], Isler 0, Huber W. Ronco A., Koxler M., Helv Chim Acta 30, [1947], No 6, 1 1ΐΐ-1 927, Helv Chim Acta 32, [1949], No 2 / 489-505].

A disadvantage of the Lindlar catalyst is the low selectivity and hence the need for selectivity by additional addition of tertiary bases such as pyridine or quinoline in hydrogenation. Such an addition is undesirable in many cases, such as in the manufacture of fragrances. In each case of using a Lindlar catalyst, high purity is required, which is difficult to achieve especially with Cd-tol, so purification procedures are required [US Pat. 730 239, 1958; SUI. U.S. Patent 385,829, 1959; Brit. pat. 887,556, 1958; AO č. However, even after the purification methods have been applied, catalyst consumption is high and the catalyst loses activity after a single use. This represents a high economic cost, since palladium catalysts are expensive, so that at least hydrogenation losses are noticeable.

The selectivization of a low percentage palladium catalyst without the addition of lead on the carrier (activated charcoal) is also carried out by the addition of alkaline lyes directly to the reaction medium, e.g. in the hydrogenation of dehydrolinalool of formula II or 3-methyl-1-butin-3-ol at a pressure of 0.3 to 0.5 MPa (Tedischi RJ, McMahon HC, Pawliak NS, AoOiN N. 4, Acad. Sci, 1967, 91) -107).

diverse nickel-based catalysts such as nickel borides or skeletal catalysts for the hydrogenation of Type I, II and III compounds do not provide compelling advantages, although they are cheaper than palladium catalysts, therefore palladium catalysts continue to be used industrially with maximum efforts to increase their efficiency (Brown CA) Brown HG, I. Am Chem Soc 85 853 (1963)).

METHOD FOR SELECTING A Lindlar Catalyst for Partial Hydrogenation of Triple Bonds of Formula (I, II, III) by Hydrogenating Lindlar Catalyst by Contacting the Lindlar Catalyst with a Petrol Solution of Technical Co-Diol Containing Alkali Residues After Alkaline Extraction and Ca 2 O The diol is hydrogenated at a pressure of 0.07 to 0.12 MPa at 10 to 40 ° C for 3 to 6 hours, under hydrodynamic conditions given by the Reynolds number Re 182 410, and then the catalyst is isolated.

Used six-blade stirrer type ON 69 1020 with a diameter d = 0.4 m, with a speed of 3.33 s ^-1 , a mixed liquid characterized by a specific gravity h - 769.8 kilograms. m ^-3 and viscosity = 2.2485. . 10 ^-3 Pa. s ^_1 .

An advantage of the process according to the invention is the use of 3 to 4 times smaller amounts of catalyst than in the prior art processes, its reuse, preferably in the manufacture of fragrances, where it removes contamination by additional selectivating agents. Another advantage is the high process selectivity in the hydrogenation of C0-diol, which results in a high yield of favorable vitamin A isomers.

The process according to the invention is illustrated by way of example without departing from the scope of the invention.

EXAMPLE

Hydrogenation of C20-diol

600 l of a gasoline solution containing 130 to 150 kg of C20 -tol, purified according to AO no. 227 942 by alkaline extraction without rinsing the alkaline salts with water of> 90 to 95% quality. In the solution thus prepared, 4-5 kg of Lindlar catalyst are added with the addition of 2 to 2.5 l quinoline. After multiple evacuations and flushing with nitrogen and then hydrogen, the reactor stirrer is started, and hydrogen is continuously fed to the autoclave with stirring at 0.07 to 0.12 MPa. The reaction temperature is maintained at 30-35 ° C. When 12,000 to 13,900 l of hydrogen were absorbed, the reactions were checked. Hydrogenation takes 3 to 5 hours. After completion of the hydrogelation, the reaction mixture is heated to 50 ° C and the catalyst used is filtered off. 3.7 to 4.7 kg of catalyst are obtained. The filtrate is concentrated on a film evaporator. The distillation residue consists of 3,7-dimethylated 1-9 - (2 ', 6', 6 ') -trimethylcyclohexene- (Γ) -yl-nomatri- (2,4,7) -diol- (1,6) in an amount 132 to 152 kg with a quality of 80 to 90% and used in the next step for the preparation of vitamin A-acetate.

Example 2

Hydrogenation of dehydnolinalylacetate

In 776 g of dehydrolinalylacetate with a content of 95% are dispersed 14 g of the selective Lindlar catalyst obtained from the production according to example no. 1. The suspension is placed in and after several evacuations and nitrogen, followed by hydrogen, stirring is started and hydrogen is added at a pressure of 1 bar. The temperature is maintained at 30 ° C + 5. When 94 L of hydrogen is absorbed, which takes about 3 hours, the hydrogenation is complete. The catalyst was filtered off and dried. 13.2 g of catalyst are obtained and can be used for further hydrogenation. The filtrate 780 g is rectified at 5 mm Hg to give 39 g of front fractions, 717 g of the main fraction, which is 98.5% limaly acetate, and 23 g of polymeric residue. The yield of linalyl acetate was 91.4% of theory.

The reuse of the catalyst b252376 has been tested 100 times, and its properties have not changed appreciably.

Example 1 and d 3

Hydrogenation of dehydrolinaloot

608 g of dehydrolinalool are mixed with 14 g of the selective Lindlar catalyst according to the process of Example 1 and hydrogenated as in Example 2 at 0 to 10 ° C. Hydrogenation lasts 5 hours. Linalool is obtained in a yield of 92 to 94% of theory. The catalyst is reusable.

Example 4

Hydrogenation of dehydrolinalylacetate by Lindlar catalyst

14 g of Lindlar catalyst are dispersed in 776 g of dehydrolinalylacetate containing 95% and hydrogenated as in Example 2. Hydrogenation takes 5 hours. The catalyst is filtered off and the filtrate is rectified at 5 mm Hg. Yield: 710 g of 91% quality linalyl acetate.

Claims (2)

Method of selectivity of Lindlar catalyst for partial hydrogenation of triple bonds in 3,7-dimethyl-9- (2,6,6) -trimethylcyclohexyne- (yl) -inonadiene- (2,7) -in- (4) -diol- (1) 6), entitled C20-diol of formula (I), 3,7-dimethyl-6-octen-yn-3-ol of formula (II) and its esters of formula (III), wherein R is an aliphatic radical having a carbon number of 1 to 4, ^CH V / ^CH 3 CHi CH ' C ^H 3 y ^CH 3 Z c = CH CH. (I) uCU-K (III) by hydrogenation using a Lindlar catalyst, characterized in that, for the first use, the Lindlar catalyst is contacted with a gasoline solution of technical C 2 -diol 10 containing alkali residues after alkaline extraction and C 2 -diol is hydrogenated under pressure 0.07 and 0.12 MPa at a temperature of 10 to 10 bar 40%, for 3 to 6 hours, under the hydrodynamic conditions given by the Reynolds number Re = 182 410 and subsequently the catalyst is isolated.