JPS5839680A - Synthesizing method of ketal derivative from glycerol allyl ether - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a monomer for raw material polymers used for preparing contact lenses, by forming a ketal derivative of allyl glycidyl ether and a ketone in the presence of an acidic catalyst at a greatly reduced cost. CONSTITUTION:Allyl glycidyl ether of formulaIis reacted with a ketone, e.g. acetone, of formula II in the presence or absence of a solvent in the presence of an acidic catalyst, preferably by adding a small amount of a polymerization inhibitor, e.g. hydroquinone monomethyl ether, thereto to give the aimed compound, e.g. the compound of formula III. Acetone, methyl ethyl ketone, cyclohexanone, etc. may be used as the ketone. The reaction temperature varies with the kinds of the ketone, and is 20-50 deg.C for the acetone and 30-60 deg.C for the methyl ethyl ketone. A Brphinsted acid, preferably silicotungstic acid or sulfuric acid, or a Lewis acid, preferably boron trifluoride ethyl etherate, may be used as the acidic catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for synthesizing ethers. This compound is used to make the raw material polymer for contact lens manufacturing! It is useful as one.

Conventionally, as a ketalized allyl ether, for example, allyl isopropylidene glycerol ether (hereinafter referred to as AL-PG) can be obtained by the synthesis method shown by the following reaction formula.
Isoprohyde(denta)cerol However, this synthesis method has the disadvantage that it requires a six-step process and therefore takes a long time to synthesize.

The present inventors have conducted extensive research to overcome the above-mentioned drawbacks, and have found that when using a method for synthesizing ketalized glycerol allyl ether, which involves reacting allyl glycidyl ether with a ketone in the presence of an acid catalyst, the above-mentioned method can be used. It was discovered that not only the disadvantages could be eliminated, but also a significant cost reduction could be achieved, and the present invention was completed.
The reaction formula for an example using E) is as follows.

υ ALGIIc That is, by directly reacting ALGI with a ketone such as acetone, methyl ethyl ketone, or cyclohexanone, AI, PG, 4-allyloxy-2-methyl-2
-ethyl-1,6-dioxymethyl (hereinafter referred to as ALMI), 2-allyloxymethylene-spiro (:4,5
) 1,4-Dioxadecane (hereinafter referred to as AllOH) and other ketalized glycerol-trO-ruallyl ethers are synthesized. This is a diagram showing the structural formula of the cholera compound.

AL PG ALMI LOH Examples of acid catalysts used in the present invention include Brønsted acids and Lewis acids. Preferred Brønsted acids include trifluoromethanesulfonic acid, nitungstic acid, and sulfuric acid; Preferred is a boron trisulfide ether complex. The amount of catalyst used varies depending on the type and type of ketone used as the starting material, but in the case of silicotungstic acid 26 hydrate, it is o, oos to 5 parts by weight of AUGIC.
parts, preferably 0.02 to 2 parts, and in the case of trifluoromethanesulfonic acid, 0.002 to 2 parts, preferably 0.
In the case of the boron trifluoride ethyl ether complex, the amount is 0.01 to 1 part, and in the case of the boron trifluoride ethyl ether complex, the amount is 0.01 to 5 parts, preferably 0.02 to 2 parts.

The amount of ketone is AI + GI [0.7 mole to 1 mole]
6 mol, preferably 2 mol to 10 mol is preferred.

If the amount of ketone is large, it will take too much time to concentrate the reactants, and if the amount is small, the reaction time will be longer.
This is not preferred because it increases the amount of by-products.

The reaction can be carried out in the presence or absence of a solvent. Examples of solvents that can be used include inert organic solvents such as nihexane, benzene, and xylene. When a solvent is not used, an excess of ketone can be used. Also, in order to suppress the polymerization of raw materials and products during the reaction, a small amount of a polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, or methoxyhydroquinone can be used. It is preferable to carry out the reaction by adding.

The reaction temperature varies depending on the type of ketone used; in the case of acetone, it is 10 to 60°, preferably 20 to 50°.
O1 is usually sufficient at room temperature, and harsh conditions are not necessary. In the case of methyl ethyl ketone, 10 to 77°0
, preferably 60 to 60°O, and in the case of cyclohexanone, 10 to 140°O, preferably 40 to 90°O.

The reaction time varies depending on the type of catalyst, the type and amount of the ketone, the reaction temperature, etc., but is usually 2 hours to 7 days.

As a result of research, the reaction in the present invention follows a process in which Lσ and ketone are consumed, the target substance and by-products are produced in equal amounts, and then the by-products disappear and finally only the target substance remains. It is something.

Next, examples of the synthesis method of the present invention will be given, but the present invention is not limited to these examples.

Example 1 (Synthesis of AL engineering pa) 0.59 silicotungstic acid was added to an 11-volume Erlenmeyer flask, and while stirring, 700 m4 of acetone and 0.0 m of hydroquinone monomethyl ether were added.
．． 2 g of the mixed solution was gradually added dropwise. After the dropwise addition was completed, stirring was continued for another 2 hours, and then anhydrous sodium charcoal was added to neutralize the mixture. Then, acetone was removed using a rotary evaporator, and 100 ml of water and 5 ml of n-hexane were added.
00 ml was added and shaken to perform separation and extraction. Add anhydrous sodium sulfate 1009 to the resulting n-hexane solution.
After adding and dehydrating, 10g of activated carbon was added and stirred.
I left it overnight. After separating the activated carbon, it is concentrated using a rotary evaporator, and the resulting residue is purified by distillation under reduced pressure to a boiling point of 50.
'O/4, 5mmH9, refractive index! 1fi0=1.4
447g of colorless transparent liquid of 314 was obtained (yield 46%).
). The obtained liquid was identified by infrared absorption spectrum and was confirmed to be AL-PG.

Example 2 (Synthesis of ALMK) 450 g of methyl ethyl ketone, 0.5 g of hydroquinone monomethyl ether and 1! l!
1.09 was added to an 11 volume round bottom flask, and AIIGK 3009 was added dropwise while stirring with a magnetic stirrer. After completion of the dropwise addition, the mixture was left to stand overnight, neutralized by adding anhydrous sodium carbonate, and further filtered.

Concentrate the p solution using a rotary evaporator, and the residue contains n-
After adding hexane 21 and washing four times with saturated brine, the n-hexane layer was separated, and after dehydration by adding 100 g of anhydrous sodium chloride, activated carbon 109 was further added and left overnight to decolorize.

After separating the activated carbon from p, the p liquid n-hexane was removed using a rotary evaporator, and the residue was purified by distillation under reduced pressure to give a boiling point of 70.5°O/4, 5 mmHg, and a refractive index of 0 np = 1.4363. 170 g of a colorless and transparent liquid was obtained (yield 34.7%). The obtained liquid was identified by infrared absorption spectrum and was confirmed to be ALMFi.

Example 6 (Synthesis of ALOH) 450 g of cyclohexanone in place of methyl ethyl ketone
The experiment was conducted in the same manner as in Example 2, except that cyclohexanone was separated and removed by distillation instead of the rotary evaporator, and the boiling point was 96°'O/1-
214 g of a colorless and transparent liquid with a diameter of 2 mm1i9, a refractive index of n:'=t, and a size of 4665 was obtained (yield: 68.4%).

The obtained liquid was identified by infrared absorption spectrum and was confirmed to be ALOH.

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Claims (1)

[Claims] 1. A method for synthesizing ketalized glycerol allyl ether, which comprises reacting allyl glycidyl ether with ten tons in the presence of an acid catalyst.