JPH0665183A - Purification of 3-cyano-3,5,5-trimethyl-1-cyclohexanone - Google Patents

Abstract

PURPOSE:To recover 3-cyano-3,5,5-trimethyl-1-cyclohexanone of remarkably high purity in a high yield by separating high-boiling impurities and a basic catalyst through the film evaporation method and avoiding decomposition of the subject compound due to the basic catalyst. CONSTITUTION:The method for separating and purifying 3-cyano-3,5,5- trimethyl-1-cyclohexanone synthesized through an addition reaction of hydrocyanic acid to isophorone in the presence of a basic catalyst by adding a high-boiling inert compound exhibiting a higher boiling point than 3-cyano-3,5,5-trimethyl-1- cyclohexanone and excellent in compatibility therewith, removing the basic catalyst and high-boiling impurities through a film evaporation column and subsequently separating and purifying the objective compound using the ordinary distillation column.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for separating and purifying 3-cyano-3,5,5-trimethyl-1-cyclohexanone obtained by addition reaction of hydrocyanic acid to isophorone using a basic catalyst. is there. 3-cyano-3,5,
5-Trimethyl-1-cyclohexanone is a useful substance as a raw material for 3-aminomethyl-3,5,5-trimethyl-1-cyclohexylamine.

[0002]

2. Description of the Related Art Conventionally, a method for producing 3-cyano-3,5,5-trimethyl-1-cyclohexanone using isophorone and hydrocyanic acid or a hydrocyanic acid compound as raw materials has been known.
For example, West German Patent No. 1240854 describes a method for producing 3-cyano-3,5,5-trimethyl-1-cyclohexanone by reacting isophorone with hydrocyanic acid using a methanol solution of an alkali metal hydroxide catalyst. Has been done. In this method, the reaction solution containing 3-cyano-3,5,5-trimethyl-1-cyclohexanone, as well as unreacted isophorone and an alkali catalyst is purified by distillation to obtain 0.5 to 1% HNO. ₃ It is described that a step of washing with an aqueous solution and separating and removing the alkali metal salt catalyst is necessary. Further, JP-B-57-116038 describes a method for producing 3-cyano-3,5,5-trimethyl-1-cyclohexanone by reacting isophorone and hydrocyanic acid in the presence of a basic catalyst and glycols. Has been done. This method describes a method in which after the reaction is completed, phosphoric acid is added to the reaction solution for neutralization, and then the neutralized salt is filtered and purified by distillation.

[0003]

In the prior art, for example, according to West German Patent No. 1240854, 3-cyano-3,5,5-trimethyl is produced by reacting isophorone with prussic acid or a prussic acid compound using an alkali catalyst. When -1-cyclohexanone was produced, it can be separated and purified by
It is necessary to perform an operation to remove the catalyst out of the system in the previous stage. As the method, an acidic aqueous solution is added to the reaction solution, and the reaction solution is washed with water to elute the alkali catalyst and / or the neutralized salt to the water phase side, and then 3-cyano-
In this method, only the organic phase containing 3,5,5-trimethyl-1-cyclohexanone, unreacted isophorone and a small amount of water is separated and sent to the distillation operation. Therefore, in addition to a washing process and a separation process of an aqueous phase and an organic phase, a treatment facility for wastewater containing a cyanide compound is required. In addition, separation and recovery of 3-cyano-3,5,5-trimethyl-1-cyclohexanone and isophorone which are dissolved in the water phase by washing with water, the high temperature reaction solution is once cooled with water, and heated again in the distillation step to recover the organic compound. There is a problem that the operation becomes complicated, such as the need to separate and collect water dissolved in the phase.

By the way, when 3-cyano-3,5,5-trimethyl-1-cyclohexanone is separated and purified by distillation, if the distillation operation is carried out in the presence of a basic catalyst, the basic catalyst becomes 3-cyano-3, 5,5-trimethyl-1-
It was found that it caused the decomposition of cyclohexanone to form isophorone and hydrocyanic acid, which significantly reduced the yield. Also, isophorone and 3-cyano-separated from the bottom of the distillation column
A mixture of an impurity having a higher boiling point than 3,5,5-trimethyl-1-cyclohexanone (hereinafter referred to as a high-boiling point impurity) and a basic catalyst (so-called bottom residue) solidifies even at 200 ° C., so that the distillation operation is performed. Is extremely difficult.

In the chemical industry and the like, usually, in the case of distillation purification of a substance which is easily affected by heat or a substance having a high boiling point, thin film distillation is carried out in which the compound is instantaneously evaporated at a high temperature. In this method, a condenser is built in the distillation apparatus under reduced pressure, and the treatment liquid inserted in a wet wall shape on the heating side of the tower wall,
By operating a cylindrical rotating body with a wiper etc. installed inside the device, it spreads out in a thin film on the wall surface to form a uniform treatment liquid film, which allows low boiling point components to evaporate in a short time and at the same time with the built-in condenser. It is a method using a device that condenses and takes out as a distillate, or a method using a distillation device that forms a thin film by centrifugal force.

However, even if a thin-film distillation method is performed in which such an evaporation surface is widened and treated in a short time, a basic catalyst is used to remove hydrocyanic acid into isophorone for the purpose of removing high-boiling impurities and basic catalyst. When the reaction solution obtained by the addition reaction of is subjected to a thin film distillation apparatus, 3-cyano-3,5,
Although 5-trimethyl-1-cyclohexanone and the light-boiling compound instantly evaporate, the amount of evaporation is so large that the liquid does not flow down on the wall surface of the column, and a continuous thin film cannot be formed on the wall surface. Therefore, the high boiling impurities and the basic catalyst stick to the wall surface. This state is extremely dangerous, and if left unattended, high-boiling impurities and basic catalyst will accumulate, and eventually wiper rotation will become impossible, leading to destruction of the device. Also, if this is tried to be avoided, the recovery rate of the reaction solution will decrease.

[0007]

[Means for Solving the Problems] In view of such a situation,
As a result of intensive studies to solve the problem, the present inventors found that
The method of the present invention has been found. That is, according to the present invention, 3-cyano-3,5,5-trimethyl-1-from a reaction solution obtained by an addition reaction of hydrocyanic acid to isophorone using a basic catalyst.
In a method for separating and purifying cyclohexanone, a thin-film distillation apparatus in which a high-boiling inert compound having a higher boiling point than 3-cyano-3,5,5-trimethyl-1-cyclohexanone and having good compatibility is made to coexist in a reaction solution. To remove the basic catalyst and high-boiling point impurities together with the high-boiling point inactive compound, and then introduce the unreacted material into a distillation column to purify 3-cyano-3,5,5-trimethyl-1-cyclohexanone. Is disclosed.

The basic catalyst used in the present invention includes sodium, potassium, barium, calcium,
Well-known basic catalysts such as hydroxides, cyanides, carbonates, oxides, alcoholates of alkali metals such as magnesium or alkaline earth metals, and alcoholates are used. As the thin film distillation apparatus, a stirring membrane type evaporation apparatus, a centrifugal type evaporation apparatus, a falling film type molecular distillation apparatus, a centrifugal type molecular distillation apparatus, etc. are used. With this treatment method, the basic catalyst and high-boiling-point impurities do not stick to the wall surface, and the liquid to be treated is continuously supplied to enable continuous purification operation.

In the method of the present invention, the high boiling point inactive compound coexisting in the liquid to be treated is 0.5 to 10 times (weight), preferably the total amount of the high boiling impurities and the basic catalyst in the liquid to be treated, preferably. Is used in an amount of 1 to 5 times. High boiling point inert compound is 0.5
If the amount is less than twice, the effect is poor, and if the amount is more than 10 times, it is not economically preferable. Also, 3-cyano-3,5,5-
Trimethyl-1-cyclohexanone, which has poor compatibility with high-boiling impurities and basic catalysts, is not preferable because it results in the high-boiling impurities and basic catalysts sticking to each other while flowing down on the heated wall surface.

The high-boiling point inert compound having good compatibility with the liquid to be treated is a compound which can be seen uniformly when coexisting with the liquid to be treated and high-boiling impurities (hereinafter referred to as a residue) containing a basic catalyst. However, even if it is not completely dissolved, it may be in a finely dispersed state. As the high boiling point inactive compound having good compatibility, isophorone or 3-cyano-3,5,5-
It is preferable that even if 10% is added to trimethyl-1-cyclohexanone, a homogeneous solution can be obtained. Also 3-cyano-
The boiling point is higher than that of 3,5,5-trimethyl-1-cyclohexanone and the difference in boiling points is large, preferably 10 ° C.
It means a substance having the above boiling point difference. By taking a large difference in boiling point, it can be easily separated from 3-cyano-3,5,5-trimethyl-1-cyclohexanone in thin film distillation. Furthermore, even if it is entrained in the distillation column due to entrainment of droplets, 3-
It can be easily separated from cyano-3,5,5-trimethyl-1-cyclohexanone.

Specific examples of the high boiling point inert compound include:
Polyethylene glycol, polypropylene glycol,
Butyl benzyl phthalate (BBP), dioctyl phthalate (DOP), tricresyl phosphate (TC)
P) and the like. Particularly preferred compounds are polyethylene glycol (having a molecular weight of 400 to 1000), BBP and DOP. Also, a mixture of these may be used. As a method for allowing such a high boiling point inert compound to coexist in the liquid to be treated, it may be added to the supply pipe to the thin film distillation apparatus as shown in FIG. 2 or as shown in FIG. It may be added to the bottom of the distillation column or directly into the reactor, and any method is possible.

[0012]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. First, a method for selecting the high boiling point inactive compound used in the present invention will be described. 3-cyano-3,5 produced by reacting isophorone and hydrocyanic acid using a basic catalyst,
5-trimethyl-1-cyclohexanone reaction solution (isophorone 18.02% by weight, 3-cyano-3,5,5-trimethyl-1-cyclohexanone 80.9% by weight, high boiling impurities 1.0% by weight, other base 100 parts isophorone and 3-cyano-3;
12 mm of 5,5-trimethyl-1-cyclohexanone
Hg was evaporated and separated at 125 ° C. under reduced pressure to obtain 1.1 parts of a residue. Table 1 shows the results of visual observation of the mixed state of the reaction liquid and the residue, which were mixed with an equal weight of the high boiling point inactive compound.

As is clear from Table 1, polyethylene glycol 400 (average molecular weight 400), butylbenzyl phthalate and dioctyl phthalate have good solubility and are suitable as high boiling point inactive compounds.

[0014]

[Table 1]

FIG. 1 is a side view of a laboratory scale distillation apparatus used for conventional thin film distillation. In FIG. 1, 1 is a 3-cyano-3,5,5-trimethyl-1-cyclohexanone synthesis reaction liquid, which is a liquid to be treated, and is kept in a heated state. The outer wall of the distillation column 2 is heated by a mantle heater 3, and a rod-shaped condenser 4 capable of circulating cooling water or a heat medium for cooling is built in the vicinity of the center of the tower, and the lower part thereof is condensed by the condenser. It is connected to a receiver 5 for receiving the treated liquid of the rectified effluent. Further, a rotating body 7 having a cylindrical frame is installed outside the rod-shaped condenser so as to have a slight gap with the column wall, and is driven by a motor 6 during distillation. In addition, a rod-shaped wiper 8 having several obliquely cut grooves is fitted into the wiper frame via a spring.

When thin film distillation is performed using this apparatus, the solution 1 consisting of the liquid to be treated 3-cyano-3,5,5-trimethyl-1-cyclohexanone synthesis reaction liquid and the high-boiling inactive compound has a dropping rate. Is adjusted by a cock and introduced through the conduit 10. The introduced liquid flowing down along the tower wall in the form of a wet wall is slid by the wiper 8 fitted in the rotating body and uniformly spread out, and is instantly vaporized in the form of a thin film. The light boiling point isophorone and 3-cyano-3,5,5-trimethyl-1-cyclohexanone are condensed by the condenser 4 installed at the center, collected in the receiver 5, and taken out. Further, the basic catalyst and high-boiling point impurities contained in the liquid to be treated flow down the column wall together with the high-boiling point inactive compound, and flow into the receiver 9
To be collected.

Since the liquid collected in the receiver 5 does not contain a basic catalyst, 3-cyano-3,
It is possible to obtain 3-cyano-3,5,5-trimethyl-1-cyclohexanone at a high recovery rate without decomposing 5,5-trimethyl-1-cyclohexanone. 2 and 3 show examples of industrial embodiments. 2 and 3
11 is 3-cyano-3,5,5-trimethyl-1-
It is a cyclohexanone synthesis reactor, and the reaction liquid is directly supplied to the thin film distillation column 12. The liquid separated in the thin film distillation column 12 is introduced into the distillation column 13, and isophorone and 3-cyano-
3,5,5-Trimethyl-1-cyclohexanone is separated by distillation. The high boiling point inert compound is added to the site shown in the figure.

In FIG. 3, a small amount of high-boiling point impurities and high-boiling point inactive compounds, which have been evaporated and / or entrained and mixed in the distillation column 3, are taken from the bottom of the column, and are labeled with 3-cyano-3,5,5-trimethyl-. Thin film distillation column 12 with part of 1-hexanone
An embodiment in the case of circulating to is shown.

[0019]

Example 1 A reaction solution of 3-cyano-3,5,5-trimethyl-1-cyclohexanone prepared by reacting isophorone with hydrocyanic acid using sodium hydroxide as a basic catalyst (18.02% by weight of isophorone, 3-cyano-3,
5,5-trimethyl-1-cyclohexanone 80.9% by weight, high-boiling impurities 1.0% by weight, other basic catalysts 0.
Polyethylene glycol 400 (average molecular weight 400) 3 g (corresponding to 1.5 times the amount of the residue) was added to 180 g (containing 08% by weight), and the mixture was heated and mixed at 80 ° C. to dissolve. Using the apparatus shown in FIG. 1, this solution was placed under a reduced pressure of 12 torr through the inlet pipe 10 and the condenser was kept at 60 ° C., and the wall temperature was about 200 ° C.
Was dropped into the column to perform thin film distillation.

The treatment time was 2 hours, and 177.3 g of an oily mixture of isophorone and 3-cyano-3,5,5-trimethyl-1-cyclohexanone was obtained from the rectification fraction receiver 5. (Recovery rate 99.6%) Its composition is isophorone 1
8.2% by weight, 3-cyano-3,5,5-trimethyl-
It was 81.8% by weight of 1-cyclohexanone. Also,
The color was colorless and transparent, and polyethylene glycol and basic catalyst were not detected.

The undistilled high boiling cut content obtained from the receiver 9 was 5.7 g, and its composition was about 53% by weight of polyethylene glycol 400 and about 3 of isophorone.
% By weight, about 10% by weight of 3-cyano-3,5,5-trimethyl-1-cyclohexanone, and about 34% by weight.

[0022]

Example 2 Thin film distillation was performed in the same manner as in Example 1 except that butylbenzyl phthalate was used instead of polyethylene glycol 400 used in Example 1 and the addition amount was 5 g. From the rectification fraction receiver 5, oily isophorone and 3-cyano-
176.8 g of a mixture of 3,5,5-trimethyl-1-cyclohexanone was obtained. (Recovery rate 99.3%) The composition is isophorone 18.3% by weight, 3-cyano-
3,5,5-trimethyl-1-cyclohexanone 81.
It was 7% by weight. The color was colorless and transparent, and butylbenzyl phthalate and basic catalyst were not detected.

The undistilled high boiling cut content obtained from the receiver 9 was 8.2 g, and the composition was about 61% by weight of butylbenzyl phthalate and about 1% by weight of isophorone.
3-Cyano-3,5,5-trimethyl-1-cyclohexanone was about 14% by weight, and the other was about 24% by weight.

[0024]

Example 3 Thin film distillation was carried out in the same manner as in Example 1 except that dioctyl phthalate was used instead of polyethylene glycol 400 used in Example 1 and the addition amount was 7 g.
From the rectification fraction receiver 5, oily isophorone and 3-cyano-3,
Mixture 1 of 5,5-trimethyl-1-cyclohexanone
75.3 g was obtained. (Recovery rate 98.5%) The composition is isophorone 18.4% by weight, 3-cyano-
3,5,5-trimethyl-1-cyclohexanone 81.
It was 6% by weight. The color was colorless and transparent, and dioctyl phthalate and basic catalyst were not detected.

The undistilled high boiling cut content obtained from the receiver 9 was 11.7 g, and the composition was about 60% by weight of dioctyl phthalate and about 2% by weight of isophorone.
-Cyano-3,5,5-trimethyl-1-cyclohexanone was about 22% by weight, and the other was about 16% by weight.

[0026]

Comparative Example 1 Thin film distillation was performed in the same manner as in Example 1. However, it was performed without adding polyethylene glycol 400. High boiling impurities and basic catalyst cling to the wall surface of the tower, and the wiper rotation failed, and it had to be interrupted.

[0027]

Comparative Example 2 The procedure of Comparative Example 1 was repeated. However, the conditions were selected such that the reaction liquid supply rate was increased and the wall surface of the tower did not stick. (Treatment time was set to 1 hour.) From the rectification fraction receiver 5, oily isophorone and 3-cyano-3,
Mixture 1 of 5,5-trimethyl-1-cyclohexanone
45.3 g was obtained. The recovery rate was remarkably lowered to 81.6%.

[0028]

Comparative Example 3 Polyethylene glycol 400 in Example 1
Instead of heat medium (Neo SK-OIL L-400)
Thin film distillation was carried out in the same manner as in Example 1 except that the amount added was 10 g. The high boiling impurities and the basic catalyst partially sticked to the wall surface of the tower, causing the rotation failure of the wiper, so that the thin film distillation could not be continued stably.

[0029]

According to the method of the present invention, in separating and purifying 3-cyano-3,5,5-trimethyl-1-cyclohexanone produced by reacting isophorone with hydrocyanic acid using a basic catalyst, There is no need to remove the catalyst in the water washing process, no facility for filtering water is required, and almost no water is brought into the distillation separation system, so there is no need for water separation and recovery, and because the liquid to be treated is washed with water. There is no need to cool down. Furthermore, after isolating and removing high boiling impurities and basic catalyst by thin film distillation, isophorone and 3-cyano-3,
Since 5,5-trimethyl-1-cyclohexanone is separated by distillation, the distillation operation is easy and the reduction in recovery rate due to decomposition can be minimized, which is extremely valuable industrially.

[Brief description of drawings]

FIG. 1 is a side view of a thin film distillation apparatus that can be used when carrying out the method of the present invention.

FIG. 2 is an example of an embodiment for industrially carrying out the present invention.

FIG. 3 is an example of an embodiment in which the present invention is industrially carried out.

[Explanation of symbols]

1 liquid to be treated 2 thin film distillation column 3 mantle heater 4 condenser 5 rectification fraction receiver 6 motor 7 rotor 8 wiper 9 high boiling point fraction receiver 10 conduit 11 3-cyano-3,5,5-trimethyl-1-cyclohexanone Synthesis reactor 12 Thin-film distillation column 13 Distillation column

Claims (1)

[Claims] 1. From the reaction solution obtained by the addition reaction of hydrocyanic acid to isophorone using a basic catalyst, 3-cyano-3,
In the method for separating and purifying 5,5-trimethyl-1-cyclohexanone, a high-boiling inert compound having a higher boiling point than 3-cyano-3,5,5-trimethyl-1-cyclohexanone and having good compatibility is reacted. The basic catalyst and high boiling point impurities are removed together with the high boiling point inactive compound by using the thin film distillation apparatus together with the liquid, and then introduced into a distillation column to separate unreacted materials and 3-cyano-3,5,5- Trimethyl-
A method for purifying 1-cyclohexanone.