JPH0452259B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing allyl carbonate of an aromatic dihydric alcohol, and specifically, it is particularly useful as a raw material for transparent organic glass with a high refractive index.
The present invention relates to a method for producing purified allyl carbonate of aromatic dihydric alcohol. Conventionally, the phosgene method, allyl chloroformate method, transesterification method, etc. have been proposed as methods for producing allyl carbonate, which is a polyhydric alcohol, but in all cases, the product is allyl carbonate, which is an aliphatic alcohol, and distillation purification is not necessary. It was possible. On the other hand, in the method of producing allyl carbonate of a polyhydric alcohol having an aromatic ring by reaction with a polyhydric alcohol having an aromatic ring and diallyl carbonate, distillation purification is impossible due to the large molecular weight, and for example, recrystallization etc. Purification is required. However, such purification by recrystallization is accompanied by a decrease in the yield of aromatic dihydric alcohol carbonate, which is the target product, and a complicated process, which is industrially expensive and complicated. Therefore, in view of the above, the present inventors conducted extensive research on a method for simply purifying and producing allyl carbonate, a polyhydric alcohol having an aromatic ring. As a result, after the reaction product of aromatic dihydric alcohol and diallyl carbonate is treated under specific conditions, the reaction solution containing the reaction product is treated with a decolorizing agent, and finally, unreacted diallyl carbonate is separated. The present inventors have discovered that a well-purified allyl carbonate of an aromatic dihydric alcohol can be obtained by the method, and have thus come to provide the present invention. That is, the present invention provides HO(-R ₁ O)- _o (R ₁ is an alkylene group having 2 or 3 carbon atoms, n is an integer of 1 to 4)
It has two alcohol residues represented by on the same or different benzene rings (however, if the benzene ring is
In the presence of a basic alkali metal compound catalyst, using an excess of diallyl carbonate with respect to an aromatic dihydric alcohol (in which both benzene rings are bonded with a hydrocarbon group), the dihydric alcohol and diallyl carbonate are combined with each other in the presence of a basic alkali metal catalyst. are reacted, then the diallyl carbonate is removed to the extent that the reaction product does not precipitate, and the catalyst is removed.Then, the reaction solution containing the reaction product is treated with a decoloring agent, and the unreacted diallyl carbonate is separated. The present invention is characterized by a method for producing allyl carbonate of the above-mentioned aromatic dihydric alcohol. The aromatic dihydric alcohol used in the present invention is a general term including its nuclear halogen-substituted alcohols, and any known alcohol can be used without particular limitation. Typical examples that can be suitably used are as follows. Specifically, for example, bis(β-hydroxy-ethoxy)benzene,

[Formula] HOCH ₂ CH ₂ OCH ₂

【formula】

Dihydric alcohols having a benzene ring such as [Formula], Dihydric alcohols having two benzene rings are preferably used. The ratio of diallyl carbonate to the aromatic dihydric alcohol as mentioned above is generally 5 to 50 times, particularly 10 to 40 times by mole, in order to achieve a good reaction.
It is preferable to use a molar excess. That is,
When the amount of diallyl carbonate used is small, allyl carbonate of aromatic dihydric alcohol, which is the target product, can be used.

In addition to [formula] , unreacted substances may remain,

【formula】

This is undesirable because it increases half esters and oligomers as represented by the formula (in the above formula, R: alcohol residue of aromatic dihydric alcohol, A: allyl group). Furthermore, if the amount of diallyl carbonate used is too large, the amount of the desired product produced per reactor volume will be reduced, which is industrially disadvantageous. The basic alkali metal compound catalyst used in the present invention generally includes NaOH, KOH, Na ₂ CO ₃ ,
Known products such as NaHCO ₃ and K ₂ CO ₃ are preferably used because they have little coloration, but especially
Generally 1mmφ for caustic alkalis such as NaOH and KOH
Powders with the following small particle sizes are suitable. The amount of the basic alkali metal compound catalyst to be used cannot be absolutely limited because it varies depending on the type of aromatic dihydric alcohol used and the reaction conditions, but it is preferably used in an amount of 1 to 30 mol% based on the dihydric alcohol used. It is. In addition, when the alcohol used is a primary alcohol, the amount of catalyst may be small, but when the alcohol used is a secondary alcohol, the reactivity is slow, so it is necessary to increase the amount of catalyst. The reaction of the present invention is preferably carried out in an inert gas atmosphere such as N ₂ gas, because if air is present, the catalyst may be deactivated by CO ₂ gas in the air or may become colored during the reaction. Further, the reaction temperature is generally preferably 50 to 150°C, and the reaction is carried out at a pressure of atmospheric pressure to 10 mmHg. Furthermore, in the present invention, in order to complete the reaction to obtain the target allyl carbonate of aromatic dihydric alcohol, it is preferable to efficiently remove allyl alcohol produced at the same time from the system. The reaction of the invention can therefore be carried out, for example, in a vessel equipped with a stirrer and a distillation column for removing the allyl alcohol formed. When allyl alcohol produced from the reaction system is removed using a distillation column as described above, a portion of diallyl carbonate during the reaction is also distilled off. However, since a considerable amount of diallyl carbonate remains in the reaction solution after the reaction is completed, sufficient decolorization cannot be achieved even if the reaction solution is previously treated with a decolorizing agent. Therefore, in general, after removing excess diallyl carbonate from the above reaction solution, the resulting yellow-colored crude product is dissolved in an organic solvent such as alcohol, treated with a decolorizing agent, and then recrystallized. It is purified by However, as mentioned above,
Such a purification method by recrystallization causes a decrease in the yield of aromatic dihydric alcohol carbonate, which is the target product, and complicates the process, making it industrially expensive and complicated. On the other hand, in the present invention, in order to obtain allyl carbonate of an aromatic dihydric alcohol that is simply and efficiently purified, the excess diallyl carbonate that is generally used is added to It is extremely important to remove at a rate of 70%, preferably between 20 and 50%. That is, according to the present invention, after removing unreacted diallyl carbonate from the reaction solution containing the reaction product to an extent that the reaction product does not precipitate, and further treating the reaction solution containing the reaction product with a decolorizing agent. By separating unreacted residual diallyl carbonate, the desired product, allyl carbonate of dihydric alcohol having an aromatic ring, is obtained without coloring. The catalyst used in the reaction accelerates the hydrolysis of the product and must be removed after the reaction. The removal method is not particularly limited,
Immediately after the reaction or after removing unreacted diallyl carbonate from the reaction solution to such an extent that no reaction product is precipitated, it is removed by washing with water, filtration, or the like. Furthermore, the reaction product may be subjected to dehydration treatment if necessary. The colored matter in the reaction product of the present invention and the cause of the coloring cannot be clearly determined. Therefore, although the method of decolorization treatment in the present invention is not absolutely determined,
Known methods generally used for decolorizing liquid materials may be employed without particular limitation. For example, there are methods of treatment with a decolorizing agent such as activated carbon and decolorizing resin, or a method of treatment with a superagent, but the method of treatment with activated carbon is particularly effective. Decolorization conditions may be appropriately determined by taking into consideration the reaction raw materials and reaction solution in advance. Generally, when activated carbon is used, 1 to 20% of the product is added to the reaction solution.
The treatment may be carried out by adding % by weight and stirring at room temperature or under heating, or by passing the reaction solution through a column packed with activated carbon. The desired product can be obtained by subsequently separating the remaining unreacted diallyl carbonate from the reaction solution treated with the decolorizing agent. The allyl carbonate is generally separated by distillation under reduced pressure under heating. The allyl carbonate of the aromatic dihydric alcohol of the present invention thus obtained, alone or in combination with other diallyl compounds, is generally produced into a transparent material with a high refractive index by known cast polymerization in the presence of peroxide. Organic glass can be obtained. Examples will be shown below, but the present invention is not particularly limited thereto. In addition, the degree of coloring in the examples was expressed according to the Hazen platinum cobalt standard (APHA). Example 1 Into a three-necked flask equipped with a thermometer, a stirrer, and a distillation column, at room temperature under an inert gas atmosphere, 2,2-bis(4-hydroxyethyloxy-
948 g of 3,5-dibromophenyl)propane and 3834 g of diallyl carbonate (hereinafter abbreviated as DAC) were added and mixed well. Next, 6.0 g of caustic soda powder was added as a catalyst, and the mixture was heated at a pressure of 70 Torr.
The mixture was heated to 90°C and reacted for 1 hour. The allyl alcohol produced was distilled off together with DAC during the reaction. Thereafter, the degree of vacuum was gradually increased and the mixture was further heated to 90° C. for 1 hour at a pressure of 30 Torr to expel 10% of the added DAC. Next, the reaction solution was cooled and the alkali components were removed by washing with water, and then 70 g of activated carbon was added and decolorized at 60° C. for 1 hour while stirring. After removing the activated carbon, excess DAC was distilled off by heating under reduced pressure (starting from 90°C x 30 Torr and ending at 95°C x 1 Torr).
1069 g (89.1% yield) of product was obtained as bottoms. When this product is analyzed using high performance liquid chromatography, I understood that it consists of Furthermore, APHA in 50% toluene solution of this
was No. 5, and it was found that it could be sufficiently used as an organic glass raw material. The refractive index of this polymer is as high as n ²⁰ _D 1.594, which is sufficiently higher than that of conventional diethylene glycol bisallyl carbonate, n ²⁰ _D 1.495, and can be used as a useful raw material for organic glass. Example 2 560 g of DAC and 4.8 g of caustic soda powder were charged into the reactor in the same manner as in Example 1. The reaction was then carried out at 90° C. under a reduced pressure of 70 Torr for 2.5 hours. Reacting the generated allyl alcohol
It was distilled off together with DAC. Thereafter, the reaction was further carried out at 90° C. for 2 hours under a reduced pressure of 25 Torr. At that time, 60% of the added DAC was distilled off. After cooling the reaction solution and removing the alkali component by washing with water, 60 g of activated carbon was added and decolorized at 60° C. for 1 hour with stirring. After removing the activated carbon, remove excess heat and pressure (starting from 90°C x 30 Torr and ending at 95°C x 1 Torr).
DAC was distilled off. 406 g (81.7% yield) of product was obtained as bottoms. The APHA of the product was number 10 and had the following composition. Dimer 8% The refractive index of the product polymer was n ²⁰ _D 1.583. Example 3 1534 g of DAC and 2.4 g of caustic soda powder were charged into the reactor in the same manner as in Example 1. The reaction was then carried out at 90° C. for 2 hours under a vacuum of 70 Torr. Reacting the generated allyl alcohol
It was distilled off together with DAC. Thereafter, the reaction was further carried out for 1 hour at 90° C. under a reduced pressure of 40 Torr. At that time, 20% of the added DAC was distilled off. After cooling the reaction solution and removing the alkali component by washing with water, 70 g of activated carbon was added and decolorized at 60° C. for 1 hour with stirring. After removing the activated carbon, remove excess heat and pressure (starting from 90°C x 30 Torr and ending at 95°C x 1 Torr).
DAC was distilled off. 423 g (84.7% yield) of product was obtained as bottoms. The APHA of the product was number 10 and had the following composition. Dimer 11% The product polymer also had a refractive index n ²⁰ _D 1.588. Example 4 1500 g of DAC and 2.3 g of caustic soda powder were charged into a reactor in the same manner as in Example 1. The reaction was then carried out at 93° C. under a vacuum of 68 Torr for 1.5 hours. Reacting the generated allyl alcohol
It was distilled off together with DAC. Thereafter, the reaction was further carried out for 1.5 hours at 95° C. under a reduced pressure of 36 Torr. that time,
30% of the added DAC was distilled off. After cooling the reaction solution and removing the alkali component by washing with water, 60 g of activated carbon was added and decolorized at 60° C. for 1 hour with stirring.
After removing activated carbon, heat and reduce pressure (90℃ x 30Torr)
(starting from 95°C x 1 Torr)
DAC was distilled off. 452 g (87.0% yield) of product was obtained as bottoms. The APHA of the product was number 10 and had the following composition. Dimer 14% The product polymer also had a refractive index n ²⁰ _D 1.582. Example 5 1.4-bis(hydroxyethyloxy)benzene
297 g, DAC 3834 g, and caustic soda powder 12.0 g were charged into the reactor in the same manner as in Example 1. The reaction was then carried out at 89° C. for 1 hour under a vacuum of 66 Torr. Reacting the generated allyl alcohol
It was distilled off together with DAC. Thereafter, the reaction was further carried out for 2 hours at 89°C under a reduced pressure of 30 Torr. At that time, 30% of the added DAC was distilled off. After cooling the reaction solution and removing the alkali component by washing with water, 70 g of activated carbon was added and decolorized at 60° C. for 1 hour with stirring. After removing activated carbon, heat and reduce pressure (90℃
Excess DAC was distilled off starting at ×30 Torr and ending at 95°C ×1 Torr). Product 512g (93.2
% yield) was obtained as a bottom residue. of the product
APHA was number 5 and had the following composition. Dimer 12% The product polymer also had a refractive index n ²⁰ _D 1.54. Example 6 475 g of 2,2-bis(4-hydroxyethyloxyphenyl)propane, 3834 g of DAC, and 12.0 g of caustic soda powder were charged into a reactor in the same manner as in Example 1. The reaction was then carried out at 90° C. for 1 hour under a vacuum of 70 Torr. Reacting the generated allyl alcohol
It was distilled off together with DAC. Thereafter, the reaction was further carried out for 1 hour at 90° C. under a reduced pressure of 30 Torr. At that time, 25% of the added DAC was distilled off. Cool the reaction solution,
After removing alkaline components by washing with water, activated carbon 70
g was added thereto and decolorized at 60° C. for 1 hour while stirring. After removing the activated carbon, remove excess DAC by heating and depressurizing (starting from 90°C x 30 Torr and ending at 95°C x 1 Torr).
was removed. 668 g (91.9% yield) of product was obtained as bottoms. The APHA of the product is number 10,
And it had the following composition. Dimer 11% The refractive index of this polymer was n ²⁰ _D 1.554. Example 7 1530 g of DAC and 4.8 g of powdered caustic soda were charged into the reactor in the same manner as in Example 1. After carrying out the reaction and post-treatment in the same manner as in Example 1, excess
DAC was distilled off to obtain 438 g (90.9% yield) of product as bottoms. The APHA of the generated portion is number 5,
And it had the following composition. and Dimer 12% The refractive index of the product polymer was n ²⁰ _D 1.593. Example 8 In the same manner as in Example 1, raw alcohol,
DAC and powdered caustic soda were charged into the reactor. The reaction was then carried out at 120° C. and a vacuum of 90 Torr for 1 hour. The allyl alcohol produced was distilled off together with DAC during the reaction. After that, at 120℃ and under a reduced pressure of 70Torr,
The reaction was continued for an additional hour. At that time, added
25% of DAC was distilled off. Thereafter, post-treatment was carried out in the same manner as in Example 1, and 1098 g of product (91.5%
yield) was obtained as a residue. The APHA of the product is 5
and had the following composition. Dimer 14% The product polymer also had a refractive index n ²⁰ _D 1.594. Example 9 4000 g of DAC and 2.8 g of powdered caustic soda were charged into a reactor in the same manner as in Example 1. The reaction and post-treatment were carried out in the same manner as in Example 2, and 496 g (88.6% yield) of the product was obtained as a bottom residue. The APHA of the product was number 5 and had the following composition. Dimer 7% Also, the refractive index of the product polymer was n ²⁰ _D 1.595. Example 10 Into a three-neck flask equipped with a thermometer, a stirrer and a distillation column, 2,2-
948 g of bis(4-hydroxyethyloxy-3,5-dibromophenyl)propane and 3834 g of diallyl carbonate (hereinafter abbreviated as DAC) were added and mixed well. Next, 6.0 g of caustic soda powder was added as a catalyst, heated to 90° C. under a pressure of 70 Torr, and reacted for 1 hour. The allyl alcohol produced was distilled off together with DAC during the reaction. Thereafter, the degree of vacuum was gradually increased, and the mixture was further heated to 90° C. for 1 hour at a pressure of 30 Torr to expel 30% of the added DAC. Next, the reaction solution was cooled and the alkali component of the catalyst was removed by filtration using filter paper, and then 70 g of activated carbon was added and decolorized at 60° C. for 1 hour with stirring. After removing the activated carbon, excess DAC was distilled off by heating under reduced pressure (starting from 90°C x 30 Torr and ending at 95°C x 1 Torr). 1145 g (95.4%) of product was obtained as bottoms. The APHA of this 50% toluene solution is 5
It was my turn. Comparative Example 1 Everything was carried out in the same manner as in Example 1, except that the DAC was expelled to 5% of the DAC used. 1065 g (88.8% yield) of the product was obtained, and the APHA of this product was good at number 5, but the composition analyzed by high performance liquid chromatography was It turns out that it is. From this result, it is clear that if the amount of DAC expelled is small, non-polymerizable raw materials and half esters remain in the product, which is not suitable as a monomer for polymerization. Comparative Example 2 In Example 1, everything was carried out in the same manner as in Example 1 except that the DAC was expelled to 90% of the DAC used, but the liquid separation condition when removing the alkaline component by water washing deteriorated. . 840 g (70% yield) of product was obtained. of this
APHA was number 30. From these results, if we push out the DAC too much,
It is clear that the monomer is not suitable as a monomer for organic glass because the liquid separation condition during water washing becomes poor, possibly due to the increase in the viscosity of the system, causing a decrease in yield and coloring of the product. Comparative Example 3 In Example 1, except that 0.075 mol of CH ₂ =CHCH ₂ ONa (20 wt% solution of allyl alcohol) was used as a catalyst instead of powdered caustic soda.
It was carried out in the same manner as in Example 1. Product 1093g (91.1
% yield) was obtained as a bottom residue. When this product is analyzed using a high performance liquid chromatograph, I understood that it consists of Also, the APHP of this item was number 30. From this result, it is clear that basic organic catalysts produce colored products and are not suitable as raw materials for organic glass. Comparative Example 4 The same procedure as in Example 1 was carried out except that the decolorization treatment with activated carbon was removed. The APHA of the resulting 50% toluene solution of the product was No. 20, and the transparency was insufficient.

Claims (1)

[Claims] 1 HO(-R ₁ O)- _o (R ₁ is an alkylene group having 2 or 3 carbon atoms, n is an integer of 1 to 4) having two alcohol residues on the same or different benzene rings (However, in the case of two benzene rings, both benzene rings are bonded with a hydrocarbon group) In the presence of a basic alkali metal compound catalyst using an excess of diallyl carbonate relative to the aromatic dihydric alcohol, The dihydric alcohol and diallyl carbonate are reacted, and then the diallyl carbonate is removed to an extent that the reaction product does not precipitate, and the catalyst is removed.Then, the reaction solution containing the reaction product is treated with a decolorizing agent, and then unreacted A method for producing allyl carbonate of an aromatic dihydric alcohol, which comprises separating diallyl carbonate.