JPH05148179A - Production of 1,1,3,4,4,6-hexamethyl-7-acetyltetralin - Google Patents

Abstract

PURPOSE:To produce high-purity 1,1,3,4,4,6-hexamethyl-7-acetyltetralin in high yield by using acetic anhydride or acetic acid chloride as an acetylating agent and acetylating 1,1,3,4,4,6-hexamethyltetralin in the presence of an anhydrous aluminum halide. CONSTITUTION:In production of 1,1,3,4,4,6-hexamethyl-7-acetyltetralin by acetylating 1,1,3,4,4,6-hexamethyltetralin in the presence of an hydrous aluminum halide by using acetic anhydride or acetic acid chloride as an acetylating agent, a chlorinated aliphatic hydrocarbon or a nitro compound having 29.2 solubility parameter at 25 deg.C is used as a solvent. A molar ratio of the anhydrous aluminum halide to acetic anhydride or acetic acid chloride is <=1.95 or <=0.98, respectively, and the reaction is carried out at 0-25 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing 1,1,3,4,4,6-hexamethyl-7-acetyltetralin (hereinafter referred to as HAT) which is widely used as a musk fragrance.

[0002]

2. Description of the Related Art Produced by acetylating 1,1,3,4,4,6-hexamethyltetralin (hereinafter referred to as HMT) with acetic anhydride or acetic acid chloride as an acetylating agent in the presence of an aluminum halide catalyst. The method of doing is known. These known reaction conditions are summarized in Table 1.

[0003]

[Table 1] * 1 AlX ₃ / AcCl: halides / acetic acid chloride * 2 AlX ₃ / HMT: halides / H
MT * 3 EDC: 1,2-dichloroethane

[0004]

However, when HMT is acetylated by the above-mentioned conventional method, the desired HA
Other than T, 1,1,3,5-tetramethyl-3-isopropyl-6 in which the tetralin skeleton is isomerized to an indane skeleton
It was found that by-products mainly consisting of acetylindane (hereinafter referred to as INA) are produced. This INA is HAT
It is difficult to separate from HAT, and significantly reduces the value of HAT as a fragrance.

In view of such circumstances, the present inventors have made earnest studies on a method for suppressing side reactions and acetylating HMT to produce HAT in a high yield. As a result, the reaction conditions in the acetylation reaction, particularly the molar ratio and When the reaction temperature was within a certain range, it was found that the side reaction was suppressed and a high yield was obtained, and the present invention was completed.

[0006]

That is, according to the present invention, acetic anhydride or acetic acid chloride is used as an acetylating agent in the presence of an anhydrous aluminum halide catalyst, 1, 1, 3,
A method for producing 1,1,3,4,4,6-hexamethyl-7-acetyltetralin by acetylating 4,4,6-hexamethyltetralin, wherein chlorine having a solubility coefficient at 25 ° C of 9.2 or more is used. Characterized in that a modified aliphatic hydrocarbon or nitro compound is used as a solvent, and the molar ratio of anhydrous aluminum halide to acetic anhydride or acetic acid chloride is 1.95 or less or 0.98 or less, respectively, and the reaction is carried out at 0 to 25 ° C. 1,1,3,4,4,6-
It is a method for producing hexamethyl-7-acetyltetralin.

The anhydrous aluminum halide used in the present invention includes aluminum trichloride or aluminum tribromide.

1, 1, 3, 4, 4, used in the present invention
6-Hexamethyltetralin can be obtained, for example, by reacting P-cymene with 3,3-dimethyl-1-butene or 2,3-dimethyl-1-butene in the presence of a tertiary alkyl halide and an anhydrous aluminum halide.

In this reaction, the molar ratio of anhydrous aluminum halide to acetic acid chloride or acetic anhydride (Al
X ₃ / CH ₃ COCL, AlX ₃ / (CH ₃ CO)
₂ O) participates in side reactions such as isomerization, while the molar ratio of anhydrous aluminum halide to HMT (AlX ₃ / H
MT) is mainly responsible for the conversion of HMT.

Regarding the side reaction, the AlX ₃ / CH ₃ COCL molar ratio within the range disclosed in the above-mentioned prior art is 1.0.
Above, it is not possible to suppress side reactions such as isomerization regardless of the reaction temperature. The reason _{is, CH 3 COCL + AlCl 3 →} CH 3 CO + · AlCl 4 represented by the following reaction formula ^- if the aluminum halide is present - pretend not involved in the formation of (I) acetylation complexes (I) It is considered that a side reaction may occur.

When acetic acid chloride is used as the acetylating agent, the AlX ₃ / CH ₃ COCL molar ratio is 0.98 or less, preferably 0.95 or less. The molar ratio is 0.
When it is 98 or less, the isomerization rate can be about 0.5% or less, and when it is 0.95 or less, it can be about 0.1% or less. Inhibiting INA by-products also reduces the production of other by-products.

When acetic anhydride is used as the acetylating agent, the AlX ₃ / (CH ₃ CO) ₂ O molar ratio is 1.
It is carried out at 95 or less, preferably 1.90 or less. This is assumed from the following equation. _{(CH 3 CO) 2 O +} 2AlCl 3 → CH 3 CO + · AlCl 4 - (I) + CH 3 as in the case of using the COAlCl ₂ acid chloride, about 0.5% isomerization rate, respectively, at most about 0.1% Can be

Since INA is difficult to separate from HAT and significantly reduces the value of HAT as a fragrance, it is desirable that the isomerization rate be about 0.5% or less, preferably 0.1% or less.

When acetic acid chloride is used as the acetylating agent, if the AlX ₃ / CH ₃ COCl molar ratio is 0.98 or less, there is no particular problem in terms of quality, but the smaller the molar ratio, the more the amount of acetic acid chloride used. Usually, the AlX ₃ / CH ₃ COCl molar ratio is set to 0.8 or more because it increases and becomes economical. When acetic anhydride is used, the AlX ₃ (CH ₃ CO) ₂ O molar ratio is 1.6 or more for the same reason. That is, it is usually performed in the following molar ratio range. 0.8 ≤ AlX ₃ / CH ₃ COCl ≤ 0.98, 1.6 ≤ AlX ₃ / (CH ₃ CO) ₂ O ≤ 1.95 This is an example performed using aluminum chloride,
It is clear from FIG. 1 showing the results of the comparative example.

On the other hand, regarding the conversion rate of HMT, when acetic acid chloride is used as the acetylating agent, AlX ₃ /
The HMT molar ratio is 1.0 or more, preferably 1.1 or more. HMT when AlX ₃ / HMT molar ratio is 1.1 or more
The conversion rate of 99% to 100%, and more than that
Even if 1X ₃ is used, improvement in conversion rate of HMT cannot be expected, and
Since the amount of IX ₃ and the acetylating agent used accordingly increases, the AlX / HMT molar ratio is usually 1.3 or less. That is, usually 1.0 ≦ AlX ₃ / HMT
≦ 1.3.

When acetic anhydride is used as the acetylating agent, Al is used for the same reason as when acetic acid chloride is used.
The X ₃ / HMT molar ratio is 2.0 or more, preferably 2.2 or more and 2.6 or less. That is, usually 2.0
≦ AlX ₃ /HMT≦2.6. These facts are clear from FIG. 2 showing the results of Examples and Comparative Examples conducted using aluminum chloride.

When the conversion is about 99% or more, the product HAT can be obtained from the reaction product by simple distillation, but below that, unreacted HAT needs to be separated by rectification.

The reaction temperature also has a great influence on side reactions and yields. When the reaction temperature exceeds 25 ° C, byproducts increase and the conversion rate of HMT also decreases. This means that the thermal stability of the acetylated complex (I) depends on the temperature, and the increase of by-products and the decrease of HMT conversion result from the free anhydrous aluminum halide due to the decomposition of the acetylated complex (I). It is estimated to be. Therefore, the reaction temperature is about 25 ° C. or lower, preferably 20 ° C. or lower. On the other hand, if the temperature is too low, the reaction rate and the solubility are lowered, so that it is preferably 0.
It is performed above ℃.

The solubility coefficient (abbreviated as SP) at 25 ° C. of the conventional so-called Friedel-Crafts reaction solvent is 9.2.
The above chlorinated aliphatic hydrocarbon or nitro compound is used as a reaction solvent. When the SP value is 9.2 or less, the reaction temperature (0 to 25 ° C) used in the method of the present invention
In the above, the reaction solution of anhydrous aluminum halide / acetic acid chloride or anhydrous aluminum halide / acetic anhydride is not uniform, and the acetyl complex (I) is not completely formed. Therefore, the reaction results deteriorate. By using a chlorinated aliphatic hydrocarbon or nitro compound having an SP value of 9.2 or more as a reaction solvent, complex formation is completed, the reaction system becomes uniform, and desired reaction results are obtained.

The solubility coefficient (SP value) at 25 ° C. is defined by the formula (1): SP = [(d / M) (ΔH-1.987T)] ^1/2 (1) d is the specific gravity at 25 ° C. (g / cc) M is the molecular weight, ΔH is the heat of vaporization at 25 ° C. (cal / g), T is 298.2 K), and the SP value at 25 ° C. is 9.2.
Specific examples of the above chlorinated aliphatic hydrocarbon or nitro compound include 1,2,3-trichloropropane (SP = 9.
5), chloroform (SP = 9.2) 1,2-dichloroethane (SP = 9.9), 1,1,2-trichloroethane (SP = 10),
Dichloromethane (SP = 9.9) and nitrobenzene (SP = 1
0).

In the method of the present invention, the order of mixing the raw materials is not particularly limited, but the acetylated complex (I) must be completely formed in advance.

In the present invention, after completion of the reaction, washing and neutralization are carried out, and HAT is isolated and obtained by a usual method such as distillation or crystallization.

[0023]

Industrial Applicability According to the method of the present invention, side reactions are suppressed, purification is facilitated, and HAT can be obtained in a high yield as compared with the conventional methods.

[0024]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The HMT conversion rate and HAT used in the following examples
The yield and the isomerization rate are defined as follows. HMT conversion rate = [(raw material HMT-remaining HMT) / raw material HMT] × 100 (%) HAT yield = [produced HAT (mol) / raw material HMT (mol)] × 100 (%) isomerization rate = [by-product INA (mol) / formed HAT (mol)] × 100 (%)

Example 1 100 ml equipped with a stirrer, condenser and dropping funnel
Anhydrous aluminum chloride (AlCl ₃ ) in a round bottom flask
8.28 g (0.062 mol) and 1,57-dichloroethane (EDC) 16.57 g were charged and stirred vigorously. Acetic anhydride (Ac ₂ O) 3.53 g (0.0
(35 mol) while keeping the internal temperature at 15 ° C over 20 minutes, and stir at the same temperature until the reaction solution becomes uniform.
A Cl ₃ -Ac ₂ O complex was synthesized (AlCl ₃ / Ac ₂
O = 1.77).

Next, 5.53 g of HMT (0.026 mo
l) was dissolved in 5.53 g of the same amount of EDC to give an internal temperature of 1
While maintaining the temperature at 5 ° C, the reaction was performed dropwise over 3 hours (Ac
₂ O / HMT = 1.35, AlCl ₃ /HMT=2.3
8). Further, the mixture was stirred at the same temperature for 20 minutes. The reaction solution obtained was added dropwise to 21.8 g of water to stop the reaction, and thereafter,
Liquid separation was carried out by standing to obtain an organic layer, which was washed successively with 21.8 g of water and 20.7 g of a 1% aqueous alkali solution and 21.4 g of water.
The obtained organic layer was 72.6 g, and when the organic layer was analyzed by gas chromatography, the HMT conversion rate =
99.6%, HAT yield = 99.6%, isomerization rate = 0.
It was 02%.

Example 2 The reaction was carried out in exactly the same manner as in Example 1 except that the charged molar ratios of AlCl ₃ , Ac ₂ O and HMT in Example 1 were changed as shown in Table 2. The results obtained are shown in Table 2.

[0028]

[Table 2]

Example 3, Comparative Example 1 The reaction was carried out in exactly the same manner as in Example 1 except that the reaction temperature in Example 1 was changed as shown in Table 3. The results obtained are shown in Table 3.

[0030]

[Table 3]

Example 4 The reaction was carried out in exactly the same manner as in Example 1 except that the reaction solvent in Example 1 was changed as shown in Table 4. The results obtained are shown in Table 4.

[0032]

[Table 4]

Example 5 100 ml equipped with a stirrer, condenser and dropping funnel
4.17 g (0.031 m) of AlCl ₃ in the round bottom flask of
ol) and 20.8 g of EDC were charged and vigorously stirred. Acetic acid chloride (hereinafter abbreviated as AcCl) 2.7 in this suspension
While keeping 5 g (0.035 mol) at an internal temperature of 15 ° C,
The mixture was added dropwise over 20 minutes and stirred at the same temperature until the reaction solution became uniform to synthesize an AlCl ₃ -AcCl complex (AlC 3.
l ₃ /AcCl=0.89).

Next, 5.58 g of HMT (0.026 mo
The solution obtained by dissolving 1) with 5.58 g of the same amount of EDC was added dropwise for 3 hours while keeping the internal temperature at 15 ° C (A).
cCl / HMT = 1.35, AlCl ₃ / HMT = 1.
19). Further, the mixture was stirred at the same temperature for 20 minutes. The obtained reaction solution was added dropwise to 21.4 g of water to stop the reaction, and after the reaction was stopped, the solution was allowed to stand to perform liquid separation to obtain an organic layer. Water 21.8 g, 1% aqueous alkali solution 20.7 g, water It was washed successively with 21.4 g. The amount of the obtained organic layer was 53.1 g, and when the organic layer was analyzed by gas chromatography, HMT conversion rate = 100%, HAT yield = 99.8%, isomerization rate = 0.
It was 02%.

Example 6 The reaction was carried out in exactly the same manner as in Example 5 except that the charged molar ratios of AlCl ₃ , AcCl and HMT in Example 5 were changed as shown in Table 5, respectively. The results obtained are shown in Table 5.

[0036]

[Table 5]

Comparative Example 2 The reaction was carried out in exactly the same manner as in Example 1 except that the charged molar ratios of AlCl ₃ , AcCl and HMT in Example 1 were changed as shown in Table 6. The obtained results are shown in Table 6.

[0038]

[Table 6]

Comparative Example 3 A reaction was carried out in exactly the same manner as in Example 1 except that the reaction solvent and reaction temperature in Example 1 were changed as shown in Table 7. The results obtained are shown in Table 7.

[0040]

[Table 7] The SP value of each solvent was carbon tetrachloride (SP = 8.6) and monochlorobenzene (SP = 9.9). In the case of carbon tetrachloride, the recovery of the organic layer was insufficient due to poor liquid separation.

Comparative Example 4 A reaction was carried out in the same manner as in Example 5 except that the charged molar ratios of AlCl ₃ , AcCl and HMT in Example 5 were changed as shown in Table 8. The results obtained are shown in Table 8.

[0042]

[Table 8]

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a molar ratio of aluminum chloride to an acetylating agent and an isomerization rate.

FIG. 2 is a diagram showing the relationship between the molar ratio of aluminum chloride to the raw material HMT and the HMT conversion rate.

Claims (6)

[Claims] 1. Use of acetic anhydride as an acetylating agent in the presence of an anhydrous aluminum halide catalyst to give 1,1,3,3.
A method for producing 1,1,3,4,4,6-hexamethyl-7-acetyltetralin by acetylating 4,4,6-hexamethyltetralin, wherein chlorine having a solubility coefficient at 25 ° C of 9.2 or more is used. Using a modified aliphatic hydrocarbon or nitro compound as a solvent, the molar ratio of anhydrous aluminum halide to acetic anhydride is 1.95 or less,
Characterized by reacting at -25 ° C 1, 1, 3,
A method for producing 4,4,6-hexamethyl-7-acetyltetralin. 2. Acetic anhydride is used as the acetylating agent in the presence of an anhydrous aluminum halide catalyst to give 1,1,3,3.
A method for producing 1,1,3,4,4,6-hexamethyl-7-acetyltetralin by acetylating 4,4,6-hexamethyltetralin, wherein chlorine having a solubility coefficient at 25 ° C of 9.2 or more is used. Using a modified aliphatic hydrocarbon or nitro compound as a solvent, the molar ratio of anhydrous aluminum halide to acetic anhydride is 1.6 to 1.95,
The molar ratio of anhydrous aluminum halide to 1,1,3,4,4,6-hexamethyltetralin is 2.0-2.
6, the reaction is carried out at 0 to 25 ° C. 1,
A method for producing 1,3,4,4,6-hexamethyl-7-acetyltetralin. 3. Using acetic acid chloride as the acetylating agent, in the presence of an anhydrous aluminum halide catalyst, 1,
Acetylation of 1,3,4,4,6-hexamethyltetralin gives 1,1,3,4,4,6-hexamethyl-7
-In the method for producing acetyltetralin, 25 ° C
And a nitro compound having a solubility coefficient of 9.2 or more are used as a solvent, and the molar ratio of anhydrous aluminum halide to acetic acid chloride is 0.98.
In the following, the reaction is carried out at 0 to 25 ° C. 1,
A method for producing 1,3,4,4,6-hexamethyl-7-acetyltetralin. 4. Using acetic acid chloride as an acetylating agent in the presence of an anhydrous aluminum halide catalyst, 1,
Acetylation of 1,3,4,4,6-hexamethyltetralin gives 1,1,3,4,4,6-hexamethyl-7
-In the method for producing acetyltetralin, 25 ° C
And a nitro compound having a solubility coefficient of 9.2 or more as a solvent, the molar ratio of anhydrous aluminum halide to acetic acid chloride is 0.8 to
0.98, 1,1,3,4,4,6-hexamethyltetralin, the molar ratio of anhydrous aluminum halide is 1.0 to 1.3, and the reaction is performed at 0 to 25 ° C. A method for producing 1,3,4,4,6-hexamethyl-7-acetyltetralin. 5. A chlorinated aliphatic hydrocarbon or nitro compound having a solubility coefficient at 25 ° C. of 9.2 or more is 1, 2,
3-trichloropropane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, dichloromethane or nitrobenzene, 1, 1, 3, 4 according to claim 1, claim 2, claim 3 or claim 4. ，
A method for producing 4,6-hexamethyl-7-acetyltetralin. 6. The 1,1,3,4,4,6-hexamethyl-methyl ester according to claim 1, claim 2, claim 3 or claim 4, wherein the anhydrous aluminum halide is aluminum trichloride.
A method for producing 7-acetyltetralin.