SU791736A1 - Method of preparing linalyl acetate from lavender oil - Google Patents

Description

one

The present invention relates to an improved process for the preparation of linalyl acetate, which is widely used in the cosmetic industry.

A known method of producing linalyl acetate from essential oils containing linalool (bua-de-roses, xo and coriander). The method of obtaining linalyl acetate from the oils of bua de roz and xo (the content of lino alool is about 85% without its impurities, esters) consists in treating these oils for 12 hours at a temperature of 14-22 With a mixture of 98-99% acetic acid and 85 % phosphoric acid. However, the authors do not indicate either the conditions for the isolation of the target product, nor its yield ±.

There is also known a method for producing linalideldetate from coriander oil (consisting in that coriander oil (65% linalool content, 5% linalyl acetate), is washed in isopropyl alcohol, and then linalool is separated by multiple distillation. The latter is acetylated and rectification gives linalyl acetate. The yield of linalyl acetate is 42.9% by weight or 66.5% based on the linalool C2 contained in the oil.

The disadvantage of this method is the large amount of wastewater containing isopropyl alcohol from the stage of saponification of coriander oil.

5 The closest technical solution is the method of obtaining linalyl acetate from lavender oil in a manner analogous to obtaining linalyl acetate from coriander oil in

10 four stages. Lavender oil

(linalyl acetate content is from 38 to 50%; linalool is from 28 to 40%) is o-oled in isopropyl alcohol, isopropyl alcohol is distilled off, the alkaline is poured off

5, the solution, saponified oil is neutralized and 95% linalool is separated by multiple distillation; Linalool is acetylated with acetic anhydride in toluene with distillation of a mixture of formed acetic acid and toluene, then linalyl acetate is isolated by distillation. The yield of the target product is 38% by weight and 47% by weight of the linolool and lin25 lyl acetate contained in the oil. 0.38 kg of sodium hydroxide and 0.62 kg of isopropyl alcohol are consumed to produce 1 kg of linalyl acetate. The amount of alkaline wastewater containing isopropyl alcohol and

30 sodium acetate, kg / kgrD

The disadvantages of this method are the large losses of oil during saponification, the large amount of wastewater, the multistage process and the low yield of the target product.

The aim of the invention is to increase the yield of the target product, simplify technology and reduce wastewater. This goal is achieved in that linalyl acetate is obtained from lavender essential oil using acetylation with acetic anhydride in toluene and isolation of linalyl acetate by distillation. A distinctive feature of this method is that lavender oil containing linalool is directly acetylated.

When rectification of acetylated lavender oil on a column with an efficiency of 6-7 tons. the initial fraction, the first and second intermediate, the commercial linalyl acetate fraction and the geranyl acetate fragment are separated. The first and second intermediate fractions contain linalool and linalyl acetate in a ratio of 3-3.5: 1.5 and 1-1.5: 3-4, respectively, as a result of this, the first intermediate fraction is attached to the original oil and sent to re-acetylation, and the second intermediate fraction is subjected to re-distillation on a column. The same efficiency to obtain an additional amount of commercial linalyl acetate. The initial fraction, the fraction with the smell of geranyl acetate and the bottoms residue are waste products.

For the distillation of acetylated lavender oil, columns with an efficiency of at least 4 TiT can be used.

The total yield of linalyl acetate is from 50 to 53% by weight and from 61.0 to 66% based on the oil linalool and linalyl acetate

The advantage of the method is an increase in the yield of linalyl acetate by 13–15%, a significant simplification of the technology (reduction of technological stages by half), reduction of wastewater.

The method is simple and during its development in production no special equipment is required.

Example. The acetylating mixture is prepared in a 1000-liter apparatus with a column and a reflux condenser of 246 kg of toluene, 193 kg of acetic anhydride (98%) and 0.4 kg of soda ash by heating up to 120 ° C and distilling some toluene with acetic acid.

Then load 350 kg of lavender oil with a content of 49% linalyl acetate and 31% linalool, heated to a temperature of 120 s and incubated for 45 minutes with a full return of the condensate. After aging, the mixture of acetic acid and toluene is distilled off at atmospheric

pressure, added to the apparatus of 246 kg of toluene. At the end of the distillation after cooling the reaction mass, another 100 kg of toluene is added and at a residual pressure of 100 mm Hg.

the acetic acid residues are distilled off and transferred to a vacuum distillation. The yield of acetylated lavender oil is 362 kg (103% by weight), containing -. esters of 72.8% per linalyl acetate.

 Acetylated lavender oil is subjected to vacuum distillation on a column with an efficiency of 6-7 tons. in the mode given in table.1.

As a result of vacuum rectification of the second intermediate fraction in the same mode and repeated acetylation of the first intermediate fraction, an additional 43.7 kg of linear alyl acetate is obtained. Total yield 53%

weight (66% based on linalool and linalyl acetate).

When using columns with efficiency of 4 tons. acetylated lavender oil is subjected to rectification in the mode shown in table 2.

Technical linalyl acetate (203 kg is again distilled on the same column in the mode given in Table 3.

When rectifying the second intermediate fractions in the same mode, as well as by acetylation and subsequent rectification of the first intermediate fraction, 54.6 kg of linalyl acetate are obtained.

The total yield of linalyl acetate is 50.1% by weight (61% based on the oil linalool and linalyl acetate).

Table 1

36.2 10 89-91 / 15

Initial

54.2 15 92-94 / 10

First intermediate

24.6 6.8 95-98 / 10

Second intermediate

4 Technical

linalyl acetate 20.3

11.9 groin geranyl acetate fractions

Cube remaining 27.9 current

Loss5,2

1.4815 Terpene hydrocarbons

1,4680 Linalool, linalyl acetate

1,4555 linalyl acetate, linalool

1.4550-1.4510 90-92% 6, 0 99-102 / 20

Namal linalyl acetate

1,4560-1,4665 Linalyl 3, 3 103-110 / 10 acetate, geranyl acetate, etc.

1,4820-1,4860

7.7 115/10

Claims (3)

The method of obtaining linalyl acetate from lavender essential oil using acetylation with acetic anhydride in toluene and isolating linalyl acetate by distillation, in order to increase the yield of the target product, simplify the process and reduce wastewater, linalool is directly acetylated. Table 3 Sources of information taken into account in the examination 1, the NDP Patent No. 51321, cl. 12о, 11 ,. published in 1966 2. The copyright certificate CCCf № 935777, cl. C 07 C 69/145, 952. 3. Instruments of the Leningrad Chemical and Food Aromatics Combine. Instructions for linalool acetylation, 1963 (prototype).