SU910572A1 - Process for producing 0-1,4-menthadiene - Google Patents

Description

(St) METHOD OF OBTAINING o-1, -MENTADIENE

one

The invention relates to the preparation of O-1, -mentadiene, which is used as a physiologically active substance and can be used in the production of fine chemicals for the production of valuable medicinal and fragrant substances.

A known method for producing o-1,4-mentadiene by reducing o-cymol with lithium in ethylenediamine in the presence of a proton-donor solvent.

The disadvantage of this method is the complexity, the complexity of the subsequent purification, the use of large quantities of ethylene diamine, as well as the low yield of the target product, amounting to wt.%,

There is also known a method for producing O-1,4-mentadien by reducing c-cymol with sodium in liquid ammonia in the presence of methyl alcohol. Output 6-1, -mentadiene in this case

is 25 wt.%. The disadvantage of this method is the use of large quantities of liquid ammonia and the need for deep cooling. -

Closest to the proposed method of obtaining o-1, -mentadiene by reduction of o-cymol with calcium hexahyamiamate in the presence of an alcoholic proton-donor solution of the bodies: primary, secondary or tertiary aliphatic alcohol. The process is carried out at a temperature from 0 to in an inert hydrocarbon solvent. Output

15 O-1, -mentadiene is 38 wt.%, Selectivity reaches 3%.

The purpose of the invention is to increase the selectivity of the process.

20

The goal is achieved by the described method of obtaining o-1,4-mentadien by reducing o-cymol with calcium hexahyammonium in the presence of an alcoholic proton-donor solvent — a mixture of isopropyl and isobutyl alcohols in a molar ratio of from 1: 1 to 5: 1 in an inert hydrocarbon solvent at 20 -25 C. Differences of the method - using as a proton alcohol donor a mixture of isopropyl and isobutyl alcohols in a molar ratio of from 1: 1 to 5: 1, as well as carrying out the process at 20-25 V tables The data on the method described are given (experiments 6, 7, 9-12), as well as data on the process in the presence of one of the alcohols - isopropyl or iso-butyl (experiments / 1- and data on carrying out the process in a known way (experiment 13) .Example: A solution of o-zimol (10 wt.h.) in a mixture of hexane 100 wt.h. isopropyl (19 wt.h.) and isobutyl (23 wt.h.) alcohols are mixed with 27 vih. Calcium calcium hexamylamine at 20–25 ° C and shaking. The mixture is kept at an ambient temperature for k hours. Then water (100 parts per hour) is added and the hexa extract is extracted. The extract is washed with water. dried over sodium sulfate. After distilling off the solvent, an oil is obtained with a yield of 80 wt. having nj5l, 4753 and containing 48 weight. o-1, 4-mentadiene By rectification in a vacuum on a column of 60 theoretical plates, O-1, -mentadiene is released in an amount of 3.5 volts. 90% purity, boiling point, n | ° 1 ,. The structure of the o-1,4-mntadiene proven spectroscopic methods. The substance is characterized by the absence of absorption at above 225 nm. IR spectrum, CM-I 3031, B70 |; cis-CH-CH-3 1) 68; 1432GSN278

37

2.0 1.0

1.0 2.0

187i

t8,55,51,5

18V1.5

9.58.51.5-cn-CHj; 1380; -CH (CHj, J. Spectrum RMPCcf, ppm): 0, S2 d; J 7 Hz; bn GOS (SN.U-1.60 C, zn GSn-s y-, 2.52 d. J 1 Hz 4H G2 CHj 2.89 m; 1 N CH, 5.50 KB; 2H G2. P r and and e p 2. The method is carried out as in example 1, but 37.5 parts by weight, isopropyl and 23 parts by weight of isobutyl alcohols are used.After treatment, the oil is obtained with a yield of 81% by weight, having n-1.47% and containing 51 wt.% o-1, -mentadiene. The distillation isolated 3.6 cpm, o-1,4-mentadiene, 95% purity, boiling point 68, (10 Mm),, t805. Pr and m p 3. The method is carried out according to Example 1, but 28 parts by weight of isopropyl alcohol and 11.5 parts by weight of isobutyl alcohol are used.Oil is obtained in 80% weight.1 having 1 point 1 containing 53.5% by weight -1, -men adiene. A distillation isolated 3.6 cc. O-1,4tmentadiene 99% pure, boiling point 68.5-69 ° C (10 mm, .. Example. Ciioco6 is carried out as in Example 1, but kj is used in i.p. of isopropyl and 11, .5 pb.i of isobutyl alcohols. 82% wt.p., having 1.750 and containing 49 wt% of o-1,4-mentadiene, are obtained from distillation. including o-1,4-mentadiene, purity, boiling point 67-68, (10 mm). P 1.4805. Thus, the method according to the invention makes it possible to increase the selectivity of the process. In addition, the process is simplified by conducting the reaction at room temperature, its duration is reduced, the yield of the desired product is exceeded. The resulting product has high physicochemical indicators.

Claims (1)

The method of obtaining o-1. -Mentadiene by reducing o-cymol to hexam | calcium nyakatom in the presence of an alcoholic proton-donor solvent in an inert hydrocarbon solvent, distinguishes (1rod | ol "tavl. This is because, in order to increase the selectivity of the process, a mixture of isopropyl and isobutyl alcohols in a molar ratio of from 1: 1 to 5: 1 is used as the alcoholic proton-donor solvent and the process is carried out at 20-25 C.