CS212915B1 - Method of preparation of the mixture of 3-phenylbutt-3-enylacetate and 4-acetoxy-2-phenylbutan-2-ol - Google Patents

Abstract

Process for the preparation of 3-phenylbut-3- phenylacetate, 3-phenylbut-2-enyl acetate, and 4-acetoxy-2-phenylbutan-2-ol for perfumery purposes. The purpose of the invention is to improve the composition Compositions suitable for fragrance compositions and enhancements their durability. This purpose is achieved by heating approximately equimolar mixture of α-methyl-atyrene and paraformaldehyde with acid acetic acid. The acid is used in an amount 1 to 5 moles per mole of methylstyrene and heating is carried out for 2 to 10 hours to 100-150 ° C. Then The mixture is isolated by distillation.

Description

The present invention relates to a process for preparing a mixture of 3-phenylbut-3-enyl acetate, 3-phenylbut-2-enyl acetate and 4-acetoxy-2-phanylbuten-2-ol for perfumery purposes by heating an approximately equimolar mixture of α-methylstyrene and paraformaldehyde and acetic acid. The mixture contains about 60 wt. % 3-phenylbut-3-enyl acetate, 20 wt. % Of 3-phenylbut-2-enyl acetate and 20 wt. 4-Acetoxy-2-phenylbutan-2-ol. Its aroma is reminiscent of geraniol and citronellol acetates and is suitable for use in pink and gerdenium complexes or as a substitute for phenylethyl acetate. In addition, it has excellent durability due to the presence of 4-acetoxy-2-phenylbutan-2-ol having excellent fixation properties.

In the known methods of obtaining a mixture of 3-phenylbut-3-enyl acetate and 3-phenylbut-2-enyl acetate, the procedure described in Ch.C. Priee, F.L. Benton and J. Schmidle in J.Amer. Chem. Soc. 71, 2860 (1949), consisting of heating 3-methylstyrene, paraformaldehyde and a large excess of acetic acid under reflux for 3 hours. Subsequently, some of the acetic acid was distilled off under normal pressure, replaced by the same amount of acetic anhydride, the mixture was heated to reflux for a further 3 hours and then distilled off. A total of 70% of theories is obtained. % of phenylbutenylacetates, of which about 75 wt. % By weight of 3-phenylbut-3-acylacatate (b.p. 135 ° C / 1.74 kPa; η θ »1.5233) and 25 wt. 3-phenylbut-2-enyl acetate (b.p. 144-145 ° C / 1.7 kPa; Πρ ° = 1.5335). The aim of this process was to obtain a maximum amount of both phenylbutenylacetates, used further for the production of phenylbutadiene by pyiolysis. The process is demanding in terms of apparatus dimensions (6 moles of acetic acid per 1 mol of CC-methylstyrene is used), handling and number of technological operations (reaction - distillation - replenishment - reaction - distillation) and consumption of acetic anhydride.

E.G.E. Hawkins and R.D. Thompson in J. Chem. Soc. 1961. 370. It is stated that by heating 118 g of α-methylstyrene, 36 g of paraformaldehyde and 333 ml of acetic acid to reflux for 1 hour, distilling off the acetic acid and fractionating, 6. g of o-methylstyrene, 48.4 g of 3- phenylbut-3-enyl acetate and 3-phenylbut-2-enyl acetate with minor amounts of the corresponding phenylbutenols and 4-phenyl-4-methyl-1,3-dioxane and 68.4 g of i-acetoxy-2-phenylbutan-2-ol ( b at 160 ° -165 ° C / 1.74 kPa; η ° = 1.5147). The molar ratios of the starting materials were the same as in J. Amer. Chem. Soc. 71. 2860 (1949), so again a large excess of acetic acid was used. A certain advantage would be the relatively short reaction time and simplicity in terms of handling and number of technological operations, but a significant disadvantage of this process from the numerical point of view is the composition of the reaction mixture after completion of the reaction, which contains relatively low odor determining phenylbenzenylacetates. phenylbutan-2-ol, whose utility value lies primarily in its fixation properties.

Nevý These disadvantages are reliably overcome by the process of preparing a mixture of 3-phenylbut-3-enyl acetate, 3-phenylbut-2-enyl acetate and 4-aethoxy-2-phenylbuten-2-ol for perfumery purposes by heating an approximately equimolar mixture of α-methylstyrene and paraformaldehyde and sweat according to the invention. Its nature is that acetic acid is used in an amount of 1 to 5 moles per mole of OC-methylstyrene and the heating is carried out for 2 to 10 times.

212 SIS hours at 100-150 ° C, whereupon the mixture is isolated by distillation. After distilling off the reaction water, unreacted acetic acid and a small amount of N-methylstyrene, vacuum distillation yielded a mixture of approximately 60% by weight. % 3-phenylbut-3-enyl acetate, 20 wt.

% Of 3-phenylbut-2-enyl acetate and 20 wt. 4-ethoxy-2-phenylbutan-2-ol, boiling in the range of 135-165 ° C, at 50 psi, useful in the perfume industry. An advantage of the process according to the invention is that the composition of the composition is far more advantageous for perfuming purposes than those known to date. Ecethanhydride is not used, and the amount of acetic acid is less than in the above described works. The fragrance properties of the composition of the invention resemble geranyl acetate, used to date for a variety of fragrance compositions. In a closed system, it is possible to raise the temperature above the boiling point and operate at elevated pressure. The procedure will be readily apparent from the description and the following examples of specific embodiments.

Example 1

A mixture of 1044 g (8.8 mol) o-methylstyrene, 318 g (10.6 mol) paraformaldehyde and 1593 g (26.5 mol) acetic acid was heated to reflux (120 ° C) for 8 hours. Thereafter, the reaction water, unreacted acetic acid and a very small amount of α-methylstyrene were distilled off, and a mixture of 580 g of 3-phenylbut-3-enyl acetate, 193 g of 3-phenylbut-2-enyl acetate and 258 g of 4-acetoxy-2 was obtained by vacuum distillation. phenylbutan-2-ol, boiling in the range of 135-165 ° C at 1.74 kPa, representing about 60% yield on < X-methylstyrene.

Example 2

The procedure was as in Example 1, except that the amount of acetic acid was reduced by no more than 1 mole per mole of X-methylstyrene and the reaction was carried out in an autoclave at 150 ° C for 2 hours. Vacuum distillation yielded a mixture of 575 g

3-phenylbut-3-enyl acetate, 193 g 3-phenylbut-2-enyl acetate and 258 g 4-acetoxy-2-phenylbutan-2-ol, boiling in the range 135-165 ° C at 1.74 kPa, giving a yield of 58 %.

Example 3

The procedure was the same as in Example 1, except that 5 mol of acetic acid was used per 1 mol of α-methylstyrene and the reaction was carried out at 110 ° C for 10 hours. Vacuum distillation yielded a mixture of 585 g of 3-phenylbut-3-enylaetate, 193 g

3-phenylbut-2-enyl acetate and 258 g of 4-acetoxy-2-phenylbutan-2-ol, boiling in the range of 135-165 [deg.] C. at 1.74 kPa, representing a yield of 62%.

Claims (1)

SUBJECT OF THE INVENTION A process for preparing a mixture of 3-phenylbut-3-anylacetate, 3-phenylbut-2-enylacetab and 4-acetoxy-2-phenylbutan-2-ol by heating an approximately equimolar mixture of α-methylstyrene and pareformaldehyde with acetic acid, characterized in that the acid is acetic acid is used in an amount of 1 to 5 moles per mole of OC-methylstyrene and heating is carried out for 2 to 10 hours at a temperature of 100 ° C to 150 ° C, after which the mixture is isolated by distillation.