JPH06293672A - Hexamethyltetralin purification method - Google Patents

Abstract

(57) [Summary] [Objective] Highly pure 1,1,3,4,4,6-hexamethyltetralin can be easily and highly purified from crude 1,1,3,4,4,6-hexamethyltetralin. It is intended to be purified and obtained at a recovery rate. [Structure] Crude 1,1,3 having a purity of 90 to 95% by weight
4,4,6-hexamethyltetralin is heated in methanol, melted and then cooled, and after adding a seed crystal at a liquid temperature of 45 to 60 ° C., cooling while continuously adding water,
Characterized by crystallization.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to 1, 1, 3, 4, 4, 6
-A method for purifying hexamethyltetralin (hereinafter referred to as HMT). 7 obtained by acetylating HMT
-Acetyl-1,1,3,4,4,6-hexamethyltetralin is used as a perfume for soaps and cosmetics.

[0002]

2. Description of the Related Art In Japanese Patent Publication No. 53-10057, HMT is produced from p-cymene, ethylene dichloride as a solvent is removed by distillation at atmospheric pressure, and then excess p-cymene is recovered under reduced pressure. , HMT with a pressure of 1 mmHg and a boiling point of 8
It is disclosed that a 0 to 90 degree colorless fraction (purity 95%) is obtained and recrystallized with an equal amount of isopropyl alcohol.

In Japanese Examined Patent Publication No. 63-64410, the solvent diethylene chloride is removed by distillation at atmospheric pressure, and then excess p-cymene is recovered under reduced pressure to obtain crude HMT having a purity of 85.7%. It is disclosed that this is recrystallized using isopropyl alcohol.

[0004]

However, in the conventional method, isopropyl alcohol is an easily soluble solvent for HMT, and the amount of its use is limited. Therefore, the purity of purified HMT is not always high, and the recovery rate is not good. Is enough.

In view of such circumstances, as a result of diligent studies on a method for purifying HMT, crude HMT is melted with methanol, seed crystals are added, and then water is continuously added and cooled for crystallization. As a result, they have found that HMT can be obtained with high purity and a good recovery rate, and the present invention has been completed.

[0006]

Means for Solving the Problems That is, according to the present invention, crude 1,1,3,4,4,6-hexamethyltetralin having a purity of 90 to 95% by weight is heated in methanol, melted and then cooled, Purification of 1,1,3,4,4,6-hexamethyltetralin, characterized in that after adding a seed crystal at a liquid temperature of 45 to 60 ° C., cooling is performed while continuously adding water and crystallization is performed. Is the law.

The crude HMT used in the present invention is not particularly limited, but it is, for example, obtained by reacting p-cymene with 2,3-dimethyl-1-butene or neohexene, and the reaction A material having a purity of about 90 to 95%, which is obtained by distilling the raw material and the reaction solvent from the liquid and distilling it if necessary, is used. When the purity is lower than this, while maintaining a high recovery rate of 90% or more,
It is difficult to obtain high purity HMT of 99% or more.

In the method of the present invention, methanol is a crude H
About 0.5 to 2.5 times the weight of MT, preferably about 1.0 to
It is used 2.0 times as much. Purified HMT if used in a small amount
Is not high, and if the purity is too high, the recovery rate of HMT deteriorates, which is not preferable. The crude HMT is mixed with methanol and then heated in methanol to melt and suspend. At this time, a part of HMT is dissolved.

The suspension is then gradually cooled. The cooling rate is usually about 1 to 10 minutes, preferably about 2 to 7 minutes. It is preferable to cool slowly because the purity is higher and the crystals are larger.
Too much time is naturally limited. Seed crystals of HMT are added at a cooling temperature of about 45-60 ° C, preferably about 50-55 ° C. If the temperature is too high, the seed crystals will dissolve, and if it is too low, the HMT crystals will precipitate rapidly, which is not preferable. The amount of seed crystals added was about 0.
It is 1 to 1% by weight. If the seed crystal is not added or the added amount is too small, the HMT crystal does not precipitate well.

After the seed crystals are added, water is continuously added. The amount of water added is about 1 to 10% by weight with respect to methanol, and this is continuously added over about 0.5 to 2 hours.
When the amount of water is larger than this, the precipitated crystals are aggregated, which is not preferable, and when the amount is small, the recovery rate of HMT becomes low. Further, if water containing about 1 to 10% by weight of water is used in advance instead of continuously adding water after the seed crystals are added, the precipitated crystals agglomerate, which is not preferable.

Crude HMT is added to methanol, stirred and heated to about 70 ° C. to melt and suspend HMT. Then, the mixture is cooled at a rate of 1 ° C for about 1 to 10 minutes, preferably 1 ° C for about 2 to 7 minutes, and seed crystals are added when the temperature reaches 45 to 60 ° C, preferably 50 to 55 ° C. Then, a predetermined amount of water is added over about 0.5 to 2 hours, further cooled, and finally cooled to about 0 to 20 ° C. This temperature is not particularly limited, but is a temperature at which crystals hardly precipitate.

The precipitated crystals are separated by filtration or centrifugation. Separated crystals contain about 1 of methanol or water.
It is preferable to wash with 10% by weight of methanol,
Crystals of higher purity can be obtained. It is preferable that the washing is performed by repulping the HMT using methanol or hydrous methanol in an amount of 1 to 1.5 times the weight of the HMT, and filtering.
This washing is usually performed twice in order to increase the purity.
After washing and drying, the product HMT is obtained.

In the method of the present invention, it is possible to obtain clean crystals by slowly stirring and growing the crystals. However, if stirring is slow, the crystals will settle to the bottom. Then, cooling and crystallization are performed. Although it is difficult to recover the second crystals from the filtrate after the crystal separation, a high purity HMT can be recovered by carrying out the method of the present invention on a product obtained by distilling and separating the tar content. it can. By repeating the method of the present invention, HMT having a purity of 99.9% or more can be obtained.

[0014]

According to the method of the present invention, highly pure 1,1,
3,4,4,6-hexamethyltetralin can be easily purified and obtained with a high recovery rate.

[0015]

The present invention will be described in detail below with reference to Examples.
The invention is not limited to these examples only.

Example 1 HMT64 having a purity of 92.7% obtained by reacting p-cymene with 2,3-dimethyl-1-butene and distilling the product.
3 g and 643 g of methanol were added into a 3 liter separable flask equipped with a stirrer and a condenser. Next, after heating and holding at 70 ° C. for 30 minutes, the temperature was lowered at a rate of 1 ° C. for 2 minutes, and when the temperature reached 55 ° C., 1.3 g of HMT seed crystal was added. 16 g of water (methanol 2.
5% by weight) was added over 1 hour. Then, it cooled at the same rate and cooled to 15 degreeC. After holding at 15 ° C for 30 minutes, suction filtration was performed with a Nutsche. After filtration, the pulp was washed twice with 450 g of methanol containing 5.0% by weight of water.
The stirring at this time was vigorous because the HMT and the solvent were separated into two layers.

The crystals were taken out and dried using a vacuum pump. The amount of HMT obtained is 548g and the purity is 99.5%.
And the recovery rate of HMT was 92.1%.

Example 2 70 g of HMT having a purity of 93.2%, methanol 136.5
g and water 3.5 g (2.5% by weight of methanol) were used, and the same procedure as in Example 1 was performed. HMT yield is 57g
The purity is 99.7%, and the HMT recovery rate is 87.3.
%Met.

Example 3 70 g of HMT having a purity of 93.2%, 133 g of methanol,
Example 1 was repeated except that 7 g of water (5.0% by weight of methanol) was used. The amount of HMT obtained was 59.4 g, the purity was 99.3%, and the recovery of HMT was 90.5%.

Comparative Example 1 The procedure of Example 1 was repeated except that 70 g of HMT having a purity of 93.2% and 140 g of methanol were used and water was not continuously added. The amount of HMT obtained was 55 g, the purity was 99.6%, and the HMT recovery rate was 84.0%.

Comparative Example 2 Example 2 was repeated except that HMT having a purity of 81.5% was used. The amount of HMT obtained was 34.1 g and the purity was 95.2.
%, And the recovery rate of HMT was 83.2%.

Claims (4)

[Claims] 1. Crude 1,1, having a purity of 90 to 95% by weight.
3,4,4,6-Hexamethyltetralin is heated in methanol, melted and then cooled, and a seed crystal is added at a liquid temperature of 45 to 60 ° C., and then water is continuously added and cooled to perform crystallization. 1, 1, 3, 4, 4, 6 characterized by
-A method for purifying hexamethyltetralin. 2. The amount of water added is 1 to 1 with respect to methanol.
It is 0% by weight, 1, 1, 3, 4, 4, 6 according to claim 1.
-A method for purifying hexamethyltetralin. 3. The amount of seed crystals added is roughly 1, 1, 3, 4,
The method for purifying 1,1,3,4,4,6-hexamethyltetralin according to claim 1, which is 0.1 to 1% by weight of 4,6-hexamethyltetralin. 4. The crystallized crystals are treated with methanol or water in an amount of 1 to 1.
A method for purifying 1,1,3,4,4,6-hexamethyltetralin, which comprises washing with 10% by weight of methanol.