JP3919032B2 - Method for producing 4,4'-dioxydiphenylcyclohexane - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for industrially advantageously producing high-purity 4,4′-dioxydiphenylcyclohexane .
[0002]
[Prior art]
4,4′-Dioxydiphenylalkane is prepared by condensing phenol and a carbonyl compound such as a ketone or aldehyde in the presence of a mineral acid or a Friedel-Crafts catalyst to produce 4,4′-dioxydiphenylalkane. A method is known in which phenol is obtained as a 1: 1 adduct with phenol, and phenol is separated from the adduct by distillation (steam distillation or the like) or extraction. (For example, Japanese Patent Publication No. 36-4794).
[0003]
However, this method requires special means such as steam distillation through a relatively high temperature state, which not only makes the operation complicated, but also indicates that impurities and coloring components by-produced by the condensation reaction cannot be removed sufficiently. There are drawbacks.
On the other hand, Japanese Patent Application Laid-Open No. Sho 62-178534 describes a method for purifying bisphenols by recrystallization using a mixed solvent comprising an alcohol and an aromatic hydrocarbon. In this method, the desired 4,4′-dioxydiphenylalkane is once separated from the product, and then recrystallized, and requires an operation of distilling off the alcohol. The rate was lowered and was insufficient to remove impurities and coloring components.
[0004]
Furthermore, in JP-A-5-78270, in a purification method of bisphenols obtained as a bisphenol / phenol adduct in a known production method from ketones and phenols, the phenol is removed from the melting point of the bisphenol / phenol adduct under reduced pressure. A method for removal at low temperatures is described. This method has an advantage not involving an operation such as distillation, but cannot completely remove impurities, coloring components, and the like contained in the adduct .
[0005]
[Problems to be solved by the invention]
The present invention is intended to provide a method for producing the desired 4,4′-dioxydiphenylcyclohexane with high purity and high yield by an industrially advantageous method.
[0006]
[Means for Solving the Problems]
In the present invention, an organic solvent is added to an inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol obtained by condensing phenol and cyclohexanone in the presence of a mineral acid or a Friedel-Crafts catalyst. temperature to dissolve the clathrate compound of 4,4'-dioxy-diphenyl cyclohexane and phenol by cooling crystallization was separated in crystalline form, and then 4,4'-dioxy-diphenyl cyclohexane, which comprises vacuum drying It is a manufacturing method.
[0007]
A feature of the present invention is that, as described above, recrystallization treatment with an organic solvent is performed at the stage of the inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol obtained by the condensation reaction of phenol and cyclohexanone , This is a method for separating the desired 4,4′-dioxydiphenylcyclohexane by substantially removing phenol by drying under reduced pressure while the clathrate is in a crystalline state.
[0008]
On the other hand, for example, according to the above-mentioned Japanese Patent Application Laid-Open No. 5-78270, a method of recrystallizing with an organic solvent after removing phenol from an inclusion compound of 4,4′-dioxydiphenylalkane and phenol is considered. However, in this case, another problem that it is difficult to dissolve 4,4′-dioxydiphenylalkane in an organic solvent and formation of an addition compound with alcohol in which 4,4′-dioxydiphenylalkane is an organic solvent, In order to remove the alcohol, there is a problem that a distillation operation is required. Furthermore, this method causes a decrease in the yield of the target product, and is further insufficient for removing impurities and colored components.
[0009]
Hereinafter, the method of the present invention will be described in more detail.
In a preferred embodiment of the present invention, an inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol is slurried by subjecting excess phenol and cyclohexanone to a condensation reaction in the presence of a mineral acid or Friedel-Crafts catalyst. Get in. Next, the slurry-like condensation reaction solution is preferably neutralized to near neutrality with an alkali such as caustic alkali or alkali carbonate, and then an organic solvent, preferably an organic solvent selected from aromatic hydrocarbons or aliphatic alcohols. And then heated and dissolved, and then cooled and crystallized to separate crystals as clathrate compounds of 4,4′-dioxydiphenylcyclohexane and phenol. Finally, this is dried under reduced pressure in a crystalline state to substantially remove phenol to produce the desired 4,4′-dioxydiphenylcyclohexane .
[0010]
The condensation reaction of the present invention is carried out by a known method. Specifically, phenol and cyclohexanone, with phenol excess (2-8 times) with respect to the normal of cyclohexanone, hydrochloride, 100 ° C. from room temperature in the presence of a mineral acid catalyst such as sulfuric acid, preferably 40 It is carried out at 60 ° C. for 1 to several hours. This condensation reaction product is usually obtained as a slurry containing water and excess phenol in addition to the desired product.
[0011]
Next, a method of neutralizing the slurry-like condensation reaction liquid to near neutrality with an alkali such as a caustic soda aqueous solution is carried out by a method known per se.
Next, in the method for recrystallization treatment with an organic solvent which is one of the features of the present invention, the slurry neutralized with an alkali as described above is first selected from an organic solvent, preferably an aromatic hydrocarbon or an aliphatic alcohol. The resultant is mixed with the organic solvent and heated to a temperature of 50 to 100 ° C., preferably 75 to 95 ° C., and completely dissolved.
[0012]
The organic solvent used in the present invention is preferably selected from aromatic hydrocarbons or aliphatic alcohols, and specific examples of aromatic hydrocarbons include benzene, toluene, xylene, chlorobenzene and the like. In addition, examples of the aliphatic alcohol include methanol and ethanol.
[0013]
Next, the cooling crystallization treatment is accomplished by cooling the inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol as crystals by cooling to a temperature of about 0 to 50 ° C.
Thus, a wet cake of an inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol in the form of white crystals is obtained. This wet cake is usually a wet cake having a water content of 3 to 30% by weight, preferably 5 to 20% by weight.
[0014]
Here, the present inventors have found that it is preferable to add water in order to remove inorganic salts produced mainly by neutralization when necessary in the recrystallization treatment using the organic solvent. Thus, mainly inorganic salts can be dissolved in an aqueous solution and removed from the system. These waters can be added simultaneously with the organic solvent or before or after the organic solvent treatment.
[0015]
Next, the reduced-pressure drying of the clathrate compound, which is another feature of the present invention, is usually 1-100 mmHg, more industrially 5-50 mmHg, and a drying temperature of 90-180 ° C. Done in a range.
[0016]
The present inventors appropriately selected the degree of vacuum and the drying temperature of the above-mentioned reduced-pressure drying, and the crystals of the inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol did not melt, that is, remained in the crystal state. It was found that by holding it, only water and other low-boiling components and phenol were efficiently distilled out, and high-purity and high-quality 4,4′-dioxydiphenylcyclohexane was easily obtained.
[0017]
【The invention's effect】
According to the method of the present invention, the desired 4,4′-dioxydiphenyl-1,1-cyclohexane is easily produced with high purity and high yield, advantageously in industrial (operational and economical). be able to.
[0018]
【Example】
Hereinafter, the method of the present invention will be described in more detail with reference to examples. In the examples, “parts” means “parts by weight” unless otherwise specified.
[0019]
Example 1
270 parts of phenol and 44.1 parts of 35% hydrochloric acid are mixed and maintained at 45-50 ° C. 42.8 parts of cyclohexanone is dripped here over about 6 hours. Thereafter, the mixture is kept at 50 to 55 ° C. for 10 hours to complete the condensation reaction. The condensation product is a slurry of an inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol using excess phenol (including hydrochloric acid and water) as a solvent.
[0020]
The slurry is neutralized with 30 to 35 parts of a 47% aqueous sodium hydroxide solution until neutral, then 150 parts by volume of toluene and 150 parts by volume of water are added, and then the temperature is raised to 92 ° C. to dissolve the crystals.
Next, it cools to about 5 degreeC, a crystal | crystallization is precipitated (crystallization), It filters and wash | cleans using toluene and water, The wet cake of a white crystal | crystallization is obtained. This wet cake is a compound (inclusion compound) obtained by adding about 1 mol of phenol to 1 mol of 4,4′-dioxydiphenylcyclohexane.
[0021]
Toluene and phenol are recovered from the filtrate.
When the wet cake is dried under reduced pressure at a temperature of 120 ° C. and a reduced pressure of 40 mmHg, water and added phenol are distilled off without melting the crystals, and high-purity 4,4′-dioxydiphenylcyclohexane is obtained. (Yield: 95% with respect to cyclohexanone, purity 99%)
[0022]
Example 2
Mix 272.6 parts of phenol and 29.4 parts of 35% hydrochloric acid and maintain at 45-50 ° C. To this, 28.5 parts of cyclohexanone is added dropwise over about 6 hours. Thereafter, the mixture is kept at 50 to 55 ° C. for 10 hours to complete the condensation reaction. The condensation product is a slurry of an inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol using excess phenol (including hydrochloric acid and water) as a solvent.
[0023]
The slurry is neutralized with 15 to 20 parts of a 47% aqueous sodium hydroxide solution until neutral, then 150 parts by volume of toluene and 150 parts by volume of water are added, and then the temperature is raised to 92 ° C. to dissolve the crystals.
Next, it cools to about 5 degreeC, a crystal | crystallization is precipitated (crystallization), It filters and wash | cleans using toluene and water, The wet cake of a white crystal | crystallization is obtained. This wet cake is a compound (inclusion compound) obtained by adding about 1 mol of phenol to 1 mol of 4,4′-dioxydiphenylcyclohexane.
[0024]
Toluene and phenol are recovered from the filtrate.
When the wet cake is dried under reduced pressure at a temperature of 92 ° C. and a reduced pressure of 1 mmHg, water and added phenol are distilled off without melting the crystals, and high-purity 4,4′-dioxydiphenylcyclohexane is obtained. (Yield: 96% with respect to cyclohexanone, purity 99%)

Claims (5)

To an inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol obtained by condensing phenol and cyclohexanone in the presence of a mineral acid or a Friedel-Crafts catalyst, an organic solvent is added and dissolved by heating. A process for producing 4,4'-dioxydiphenylcyclohexane , characterized in that an inclusion compound of 4,4'-dioxydiphenylcyclohexane and phenol is separated in the form of crystals by cooling crystallization and then dried under reduced pressure. The inclusion compound of 4,4′-dioxydiphenylcyclohexane and phenol obtained by condensing phenol and cyclohexanone in the presence of a mineral acid or Friedel-Crafts catalyst is neutralized with alkali, and then the organic solvent is removed. in addition, heated and dissolved, the inclusion compounds of the cooling crystallization 4,4'-oxydiphenyl cyclohexane and phenol is separated in the form of crystals, then characterized by drying under reduced pressure 4,4-di Production method of oxydiphenylcyclohexane . The method for producing 4,4′-dioxydiphenylcyclohexane according to claim 1, wherein the organic solvent is selected from aromatic hydrocarbons or aliphatic alcohols. The method for producing 4,4'-dioxydiphenylcyclohexane according to any one of claims 1 to 3, wherein the drying under reduced pressure is carried out in a crystalline state. The method for producing 4,4'-dioxydiphenylcyclohexane according to any one of claims 1 to 4, wherein water is used together when the organic solvent is added.