JPH0525872B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing diallyl carbonate, a polyhydric alcohol having an aromatic ring, by reacting a polyhydric alcohol having an aromatic ring with diallyl carbonate (hereinafter abbreviated as DAC) in the presence of a basic catalyst. The resulting diallyl carbonate, a polyhydric alcohol having an aromatic ring, is utilized in the production of transparent organic glasses with a higher refractive index, which are more useful than conventional aliphatic diallyl carbonates, by polymerization reactions, particularly cast polymerization. Conventionally, diallyl carbonate, a polyhydric alcohol, has been produced by a two-step synthesis method using the phosgene method or by the reaction of allyl chloroformate and polyhydric alcohol, but in both reactions, in order to remove the hydrochloric acid produced, is carried out in the presence of a base such as pyridine or caustic soda. In addition, the phosgene method is troublesome because the raw material phosgene is extremely poisonous and requires careful handling. In the present invention, allyl carbonate of a polyhydric alcohol having an aromatic ring can be obtained more easily and safely than conventional methods without the above-mentioned drawbacks. That is, the present invention involves reacting a polyhydric alcohol having an aromatic ring with diallyl carbonate in an amount of 5 to 40 times the mole of the polyhydric alcohol in the presence of a basic inorganic compound catalyst, and then removing unreacted components from the reaction solution. This is a method for producing allyl carbonate of a polyhydric alcohol having an aromatic ring, which is characterized by separating diallyl carbonate to obtain a reaction product, dissolving the reaction product in a soluble solvent, and then treating it with a decolorizing agent. The present invention will be explained in detail below. The polyhydric alcohol having an aromatic ring used in the present invention is a general term including its nuclear halogen-substituted alcohol, and any known alcohol can be used without particular limitation. Typical examples that can be suitably used are as follows. Specifically, for example, xylylene diol, bis(β-hydroxy-ethoxy)
benzene,

【formula】

Polyhydric alcohols having a benzene ring such as Polyhydric alcohols having two benzene rings, etc., are preferably used. DAC for polyhydric alcohols with aromatic rings
The usage ratio of is preferably 5 to 40 times by mole, particularly preferably 10 to 30 times by mole. If the amount of DAC used is too small, unreacted substances may remain, and the amount of half esters and oligomers shown below will increase, which is not good. Raw material: HOROH (in the formula, R: alcohol residue of polyhydric alcohol having an aromatic ring) Half ester:

[Formula] A: Allyl basis) Target product:

【formula】 Oligomer:

[Formula] Furthermore, if the amount of DAC used is too large, the amount of product produced per reactor volume decreases, which is industrially disadvantageous. As the basic catalyst used in the present invention, known catalysts can be used, but NaOH, Na ₂ CO ₃ , sodium alcoholate, organic bases, metallic sodium, basic ion exchange resins, etc. are suitable. The amount of catalyst to be used varies depending on the type of polyhydric alcohol having an aromatic ring used and the reaction conditions, so it cannot be absolutely limited, but it is 1 to 1 to 1 for the polyhydric alcohol used.
Preferably, it is used at 30 mol%. When the alcohol used is a primary alcohol, the amount of catalyst may be small, but when the alcohol is a secondary alcohol, the reactivity is slow, so it is necessary to use a large amount of catalyst. The reactions of the present invention are carried out in an inert gas atmosphere such as _N2 . If air is present, the CO ₂ gas in the air may deactivate the catalyst or cause it to become colored during the reaction. The reaction temperature is preferably 50 to 150°C, and the reaction is carried out at atmospheric pressure to 10 mmHg. In the reaction of the present invention, a polyhydric alcohol having an aromatic ring and DAC are reacted in the presence of a basic catalyst,
In order to obtain the target allyl carbonate of polyhydric alcohol having an aromatic ring, it is necessary to efficiently remove allyl alcohol (hereinafter abbreviated as AOH) produced by the reaction from the system. Next, in the present invention, unreacted diallyl carbonate is separated from the reaction solution containing the above reaction product to obtain a reaction product. Since the reaction product is generally obtained as a solid, it is necessary to decolorize it by dissolving it in a soluble solvent, such as an alcohol, and contacting the solution with a decolorizing agent, such as activated carbon. One specific example of the present invention is shown below. The reaction of the invention can be carried out in a vessel equipped with a stirrer and a distillation column to remove the allyl alcohol (AOH) produced. First, raw materials polyhydric alcohol having an aromatic ring and DAC are supplied in a desired molar ratio into a container. After replacing the inside of the container with inert gas, the catalyst is added. Under stirring, pressure 100
Start heating at ~150Torr. The produced AOH is efficiently distilled off and the reaction is completed in 1 to 2 hours. After the reaction is completed, the contents are cooled and washed with water to remove the basic catalyst from the system. Next, remove excess from the reaction solution.
By distilling off DAC under reduced pressure, a crude reactant, allyl carbonate of a polyhydric alcohol having an aromatic ring, is obtained. Next, an appropriate solvent such as alcohol is added to the crude reaction product, decolorized with activated carbon, and then recrystallized to produce an allyl carbonate product of a polyhydric alcohol with an aromatic ring, which is industrially valuable as a raw material for organic glass. is obtained. This crude reaction product is purified by conventional purification methods such as recrystallization. Refined products include

【formula】 As the main component,

It contains 5 to 18% of the dimer represented by the formula. The obtained allyl carbonate of polyhydric alcohol having an aromatic ring can be mixed alone with other diallyl compounds and polymerized into an organic glass with a high refractive index useful by known cast polymerization in the presence of peroxide. I can do it. The present invention will be specifically explained below based on Examples, but the present invention is not limited thereto. In addition, the degree of coloring of the liquid in the examples was expressed according to the Hazen platinum cobalt standard (APHA). Example 1 In an Erlenmeyer flask equipped with a thermometer, a stirrer, and a distillation column, at room temperature under an inert gas atmosphere, 2,2-bis(4-hydroxyethyloxy-
1.5 moles of 3,5-dibromophenyl)propane and
Added 27 moles of DAC and mixed well. Next, as a catalyst, use a basic inorganic compound shown in the catalyst column of Table 1.
0.079M (18% solution of allyl alcohol) was added, heated to 90°C under a pressure of 70 Torr, and reacted for 2 hours. Reacting with 3 moles of allyl alcohol produced
It was distilled off together with DAC. Next, cool the reaction solution and
The alkaline components were removed by washing with water. The reaction solution was heated under reduced pressure (90° C. x 30 Torr) to remove excess DAC. 1147.1g of product colored yellow as pot residue
(95.6% yield) was obtained. Next, 425 ml of toluene, 1000 ml of methanol, and 50 g of activated carbon were added to the above crude product, and the mixture was decolorized at 55° C. for 1 hour with stirring. After removing the activated carbon, the solution was cooled to 0°C and crystallized. The produced crystals were filtered and dried to obtain the products in yields shown in Table 1. When this product is analyzed by liquid chromatogram, I understood that it consists of Furthermore, it was found that the APHA of the 50% toluene solution of the product obtained in Table 1 No. 1 was No. 5, and it could be used as a raw material for organic glass. The refractive index of this polymer is as high as η _D ²⁰ 1.594, which is sufficiently higher than the refractive index η _D ²⁰ 1.495 of conventional diethylene glycol bisallyl carbonate, and can be a useful raw material for organic glass.

[Table] Shows compounds.
Example 2 The same procedure as in Example 1 was carried out except that 7 times the mole of DAC was used relative to 2,2bis(4-hydroxyethyloxy-3,5-dibromophenyl)propane. The composition of the product was increased in dimer as shown below. Allyl carbonate formula () 68% Dimer formula () 32% Comparative example 1 The same procedure as in Example 1 and No. 1 in Table 1 was carried out except that the activated carbon treatment was not performed. As a result, a 50% toluene solution of the resulting product
APHA was number 20 and was not transparent enough. Comparative Example 2 2.8 mol of tetraethylene glycol and 34 mol of DAC were added to a three-necked flask equipped with a thermometer, a stirrer, and a distillation column at room temperature under an inert gas atmosphere and mixed well. Next, 0.14 mol of NaOH powder was added as a catalyst, and the mixture was heated to 90° C. under a pressure of 70 Torr and reacted for 2 hours. The allyl alcohol produced was distilled off together with the reaction mark DAC. Next, the reaction solution was cooled and washed with water to remove alkaline components. Heat the reaction solution under reduced pressure (90℃ x 30Torr) to remove excess DAC.
By expelling the residue, 313.1 g (86.4% yield) of a colorless and transparent liquid product was obtained as a residue. The 50% toluene solution of this product had APHA number 0.

Claims (1)

[Claims] 1 A polyhydric alcohol having an aromatic ring and diallyl carbonate in an amount of 5 to 40 times the mole of the polyhydric alcohol are reacted in the presence of a basic inorganic compound catalyst, and then unreacted diallyl carbonate is separated from the reaction solution. A method for producing allyl carbonate of a polyhydric alcohol having an aromatic ring, which comprises obtaining a reaction product, dissolving the reaction product in a soluble solvent, and then treating the reaction product with a decolorizing agent.