JPS6345376B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing glycol diethers, specifically alkylene glycol diethers and/or polyalkylene glycol diethers (hereinafter referred to as (poly)alkylene glycol diethers). . As a conventional method for synthesizing (poly)alkylene glycol diethers, there is a method of the following formula (2) as described in "Autograph" 2(1), 27, (1978).

The method of formula (2) above is a method using metallic sodium, and metallic sodium is a water-prohibited substance that belongs to the second class of dangerous substances, and is a very dangerous substance. Since it is difficult to handle, it is not suitable as an industrial manufacturing method.

The present inventors have conducted various studies in order to find a method for producing (poly)alkylene glycol diethers safely, easily, with high yields, and which is suitable for industrial use, and as a result, the present invention has been achieved.

That is, the present invention is based on the general formula R ¹ -O-(AO)- _o H (1) (wherein, R ¹ is a hydrogen atom or a hydrocarbon group,
A is an ethylene group, a propylene group or an isopropylene group. n is an integer from 1 to 4. ) is reacted with an organic halide in the presence of an alkaline aqueous solution and a quaternary ammonium salt phase transfer catalyst. ) This is a method for producing alkylene glycol diethers.

The alkaline aqueous solution used in the present invention includes alkali metal hydroxides such as sodium hydroxide,
Potassium hydroxide; alkali metal carbonates such as sodium carbonate, potassium carbonate, and aqueous solutions of mixtures thereof; Among these, preferred are aqueous solutions of sodium hydroxide and potassium hydroxide.

The initial concentration of alkaline aqueous solution is usually 20~ by weight.
75%, preferably 30-60%. When the initial concentration of the alkaline aqueous solution is lower than 20%, the reaction rate is slow, separation of the reaction product becomes difficult, and the yield tends to decrease. In the present invention, the initial concentration refers to the concentration of alkali metal hydroxide or alkali metal carbonate relative to the total amount of water and alkali metal hydroxide or carbonate at the time of reaction initiation or charging.

Sodium hydroxide, potassium hydroxide, etc. in the alkaline aqueous solution are consumed as the reaction progresses, so sodium hydroxide, potassium hydroxide, etc. are continuously or intermittently replenished into the reaction system to maintain the above concentration. It is preferable to do so. The concentration of the alkaline aqueous solution can be checked by a method such as neutralization titration. In the present invention, the alkaline aqueous solution may be an aqueous solution obtained by separately adding sodium hydroxide or the like and water to the system.

Examples of phase transfer catalysts used in the present invention include "Phase Transfer Catalyst", co-authored by W. P. Weber and G. W. Gokel, co-translated by Iwao Tabuse and Takako Nishitani; Published by Kagaku Dojin Co., Ltd. (1978), pp. 7-16; Chemtech, No.
pp. 110-117, February issue (1980) and Ryohei Oda,
Examples include catalysts described in "Chemistry and Industry", Vol. 26, No. 6, pp. 322-327 (1973). Specific examples include quaternary ammonium salts.

The quaternary ammonium salt has ^the general formula R ² ₄ ^{N +} It may contain other atoms or atomic groups such as ether bonds, ester bonds, acid amide bonds, S, N, etc., or may have a benzene ring or a naphthalene ring. Other R ² is an alkyl group having 1 to 10 carbon atoms,
They are a benzyl group and a lower hydroxyalkyl group. X ^- is an anionic counterion e.g. halogen ion, (Cl ^- , Br ^- , I ^-, etc.), CH ₃ OSO ₃ ^- ,
C ₂ H ₅ OSO ₃ ^- HSO ₄ ^- , H ₂ PO ₄ ^- , CH ₃ CO ₂ ^- ,
CH ₃ C ₆ H ₄ SO ₃ ^- , NO ₃ ^- , CH ₃ SO ₃ ^- , etc. (preferably halogen ion, HSO ₄ ^- )].

A nitrogen ring-containing quaternary ammonium salt can also be used. Examples of the nitrogen ring include a pyridine ring, a picoline ring, a quinoline ring, an imidazoline ring and a morpholine ring.

Specific examples of quaternary ammonium salts include the following.

(a) Benzyl trialkylammonium salt (alkyl group usually has 1 to 8 carbon atoms, preferably 1 to 8 carbon atoms)
4) Benzyltrimethylammonium chloride, benzyltriethylammonium bromide, benzyltriethylammonium chloride, etc. (b) Tetraalkylammonium salt (alkyl group usually has 1 to 8 carbon atoms) Tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium hydrogen sulfate,
trioctylmethylammonium chloride,
trioctylethylammonium chloride,
Tricabrylmethylammonium chloride, etc. (c) Nitrogen ring-containing quaternary ammonium salt Alkyl pyridinium [alkyl group with 8 to 20 carbon atoms, (hereinafter the alkyl group in this item (c) refers to the same thing) ) For example, N-lauryl viridinium chloride, alkyl vicolinium salts (such as N-lauryl vicolinium chloride), alkylimidazolines and hydroxy lower alkylimidazolines (such as 1-hydroxyethyl-2-alkylimidazoline), etc. Quaternary ammonium Among salts, preferred ones are
Those described in (a) and (b).

In the general formula (1) representing (poly)alkylene glycols and/or (poly)alkylene glycol monoethers, R ¹ is a hydrogen atom or a hydrocarbon group. Hydrocarbon group has 1 or more carbon atoms
20 alkyl groups (methyl, ethyl, pentyl, octyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, etc.), alkenyl groups with 1 to 20 carbon atoms (allyl,
butenyl group, oleyl group, etc.), alkynyl group (acetylenyl group, etc.); aromatic hydrocarbon group such as aryl group (phenyl group, naphthyl group, etc.),
Aryl substituents such as aralkyl groups (benzyl group, phenethyl group, etc.), aralkenyl group (cinnamyl group) and substituted aryl groups such as alkaryl group (aryl group substituted with an alkyl group having 1 to 20 carbon atoms such as tolyl group and nonylphenyl group) ); and cycloalkyl groups (such as cyclohexyl group). Among these, preferred are hydrogen atoms, lower (C ₁ - C ₄ ) alkyl groups,
Alkenyl groups, alkynyl groups, aryl and aracyl groups are particularly preferred, and particularly preferred are hydrogen atom, methyl group, ethyl group, allyl group, butenyl group, acetylenyl group, phenyl group and benzyl group.

A is an ethylene group, a propylene group, or an isopropylene group [hereinafter referred to as a (substituted) alkylene group]. ]
and the n (substituted) alkylene groups may be the same or different. A (substituted) alkylene group forms an oxy (substituted) alkylene group together with an oxygen atom, but if there are two or more types of oxy (substituted) alkylene groups, the bonds between the oxy (substituted) alkylene groups can be either block or random bonds. But that's fine. Among the (substituted) alkylene groups, preferred are ethylene groups, propylene groups, and combinations thereof.

n may be an integer from 1 to 400, but the reaction solvent,
For many uses such as polymer solvents and gas absorbents, n is preferably 1 to 4.

Specific compounds include (poly)alkylene glycol monoethers [ethylene glycol monomethyl ether, propylene glycol monomethyl ether; diethylene glycol monomethyl ether, 1,2-butylene glycol-1-monomethyl ether; 1,2-butylene glycol-
2-monomethyl ether; ethylene glycol monoethyl ether, triethylene glycol monoethyl ether; ethylene glycol monophenyl ether; α-methoxyphenethyl alcohol; β-methoxyphenethyl alcohol, polyethylene glycol monostearyl ether (average molecular weight 4800 or 5500), polyethylene glycol monononyl phenyl ether (average molecular weight
6500)] and (poly)alkylene glycols [triethylene glycol, tetraethylene glycol, polyethylene glycol (average molecular weight 8000), etc.].

Examples of the organic halogen compounds used in the present invention include alkyl halides, alkenyl halides, and aralkyl halides. Halogens include chlorine, bromine and iodine.

Specifically, examples of alkyl halides include halides having a straight chain or branched alkyl group having 20 to 20 carbon atoms (methyl chloride, ethyl bromide, isopropyl iodide, n-hexyl chloride, octyl bromide, 2-ethylhexyl bromide, chloride, stearyl chloride, etc.). As an alkenyl halide, carbon number is 1~
Examples include alkenyl halides having 20 straight-chain or branched alkenyl groups (allyl chloride, allyl bromide, allyl iodide, butenyl chloride, oleyl chloride, etc.). Aralkyl halides include benzyl chloride,
Examples include p-methylbenzyl bromide and α-methylbenzyl iode. Among these, preferred are alkyl halides, and particularly preferred are methyl chloride, ethyl bromide, and n-hexyl chloride.

The amount of the alkaline aqueous solution used in the present invention may be at least the stoichiometric amount per terminal hydroxyl group of the raw material (poly)alkylene glycols and/or (poly)alkylene glycol monoethers, but is preferably 1.5 times as much. The amount is preferably 2 to 5 times the mole or more, particularly preferably 2 to 5 times the mole. If the amount used is more than 5 times the mole, there will be no problem with the reaction itself, but excess alkali will remain, resulting in increased costs.

The amount of the phase transfer catalyst used is usually 0.1 to 30%, preferably 1 to 10%, based on the weight of the alkylene glycols and/or alkylene glycol monoethers. If the amount used is less than 0.1%, the reaction rate will be slow, and if it exceeds 30%, there will be no particular harm, but the cost will be high.

The amount of organic halide to be used is 0.8 to 10.0 times the mole, preferably 1.05 to 5.0 times the mole, particularly preferably 1.2 to 3.0 times the mole per terminal hydroxyl group of the (poly)alkylene glycols and/or (poly)alkylene glycol monoethers. It is twice the mole.

In carrying out the present invention, there are no particular restrictions on the order in which the components are added or added. For example, first (poly)alkylene glycol or/and (poly)alkylene glycol monoether,
Examples include a method in which an alkaline aqueous solution is charged, then a phase transfer catalyst is added, and a paid halide is added dropwise while stirring at a predetermined temperature, and a method in which all reaction components are charged at once. The alkaline aqueous solution and the phase transfer catalyst may not necessarily be added at the same time.
Either one may be added first and reacted to some extent, and then the other may be added.

The reaction temperature usually ranges from room temperature to 200℃,
Preferably it is 40°C to 150°C. At temperatures lower than room temperature, the reaction rate decreases, and at temperatures higher than 200°C, side reactions increase. The reaction time is usually 0.5 to 20 hours, preferably 2 to 10 hours. The reaction is carried out under pressure, under reduced pressure,
Although it can be carried out under any normal pressure, it is usually carried out under normal pressure or under increased pressure.

The reaction can be carried out without a solvent or in the presence of a solvent. When conducting in a solvent, the solvent is an aliphatic hydrocarbon (hexane, peptane, pentane, etc.),
Examples include aromatic hydrocarbons (toluene, xylene, benzene, etc.), nitrile solvents (acetonitrile, propionitrile, benzonitrile, etc.), ether solvents (diethyl ether, dipropyl ether, etc.), and mixtures thereof.

The end point of the reaction can be checked by gas chromatography.

After the reaction is completed, the organic layer is separated by filtration if necessary. (Poly)alkylene glycol diethers are obtained by distilling the separated organic layer (at normal pressure or reduced pressure). When distillation is difficult due to the high boiling point of the organic layer, after extraction with n-hexane,
-(Poly)alkylene glycol diethers are obtained by distilling off hexane under reduced pressure.

The present invention has the advantage that (poly)alkylene glycol diethers can be produced more safely and easily than conventional methods. Specifically, diethers can be produced with high reaction rate and high selectivity under relatively mild reaction conditions. Therefore, it is significant as an industrial manufacturing method. It is particularly useful as a method for producing low molecular weight (poly)alkylene glycol diethers.

The (poly)alkylene glycol diethers obtained in the present invention have two or more oxygen atoms in one molecule and can take a chelate coordination structure due to their donor properties, so they exhibit unique properties and have a low molecular weight. Those (for example, n is 1 to 20) are used as organic synthesis reaction solutions, as solvents for various polymers, and as gas absorbents. Moreover, those with high molecular weight (for example, n is 200 or more) are used as thickeners.

When a phase transfer catalyst is not used in the present invention, the reaction temperature becomes high and the reaction time becomes long. Moreover, in this case, a considerable amount of residual reactants remains and by-products are produced regardless of the reaction temperature. Hydrolysis reactions of organic halides are also likely to occur.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 194 g (1.0 mol) of triethylene glycol monoethyl ether and 50% aqueous potassium hydroxide solution in a Erlenmeyer flask equipped with a thermometer and a condenser.
224g and 10g of tetrabutylammonium bromide were charged and stirred with a magnetic stirrer at 40℃ for 30 minutes to produce 188g of ethyl bromide.
(1.5 mol) was added dropwise. 4 at the same temperature after the completion of dropping.
Allowed time to react. After the reaction, the reaction mixture was filtered, and the organic layer was separated and distilled under reduced pressure to obtain triethylene glycol diethyl ether with a yield of 85%.

Example 2 Ethylene glycol monomethyl ether was placed in a stainless steel autoclave equipped with a stirrer.
114g (1.5mol), 240g 50% sodium hydroxide
(3.0 mol) and 9.6 g (0.0450 mol) of triethylbenzylammonium chloride,
While stirring at 70°C, 98 g (1.94 mol) of methyl chloride was injected under pressure over a period of 3 hours. After the injection, the reaction was continued at the same temperature for an additional 1 hour. After the reaction is complete, filter, separate the organic layer, and distill at normal pressure.
Dimethyl ether of ethylene glycol was obtained with a yield of 90%.

Example 3 Ethylene glycol monomethyl ether in one Erlenmeyer flask equipped with a thermometer and condenser
1168g (2.21mol), 50% Sodium Hydroxide 3354
(4.42 mol) and 22 g of tetrabutylammonium hydrogen sulfate were charged, and while stirring with a magnetic stirrer, 336 g (6.63 mol) of methyl chloride was blown in at normal pressure over a period of 5 hours. After the blowing was completed, the reaction was further continued for 1 hour. After the reaction was completed, the organic layer was filtered, and the organic layer was separated and distilled under normal pressure to obtain ethylene glycol dimethyl ether in a yield of 90%.

Example 4 If the same procedure as in Example 1 was carried out using 1 mole of 2-ethylhexyloxydipropoxyethanol instead of triethylene glycol monoethyl ether, 2- as a fraction of 78-83°C/2 mmHg
Ethylhexyloxydipropoxyethoxyethyl was obtained with a yield of 74%, and when 1 mol of lauryloxytriethoxypropanol was used, 98-103
Lauryloxytriethoxypropoxyethyl was obtained in a yield of 74% as a fraction at °C/1.5 mmHg.

Furthermore, in Example 2, when 1 mol of dipropylene golicol was used instead of ethylene glycol monomethyl ether and 2.8 mol of octyl bromide was used instead of methyl chloride, the temperature was 138-153℃/2 mm.
Dipropylene golycol dioctyl ether was obtained as a Hg fraction with a yield of 65%.

When allyl bromide was used in place of methyl chloride in Example 3, ethylene glycol methyl allyl ether was obtained in a yield of 87%.

Claims (1)

[Claims] 1 General formula R ¹ —O—(AO)— _o H (1) (wherein R ¹ is a hydrogen atom or a hydrocarbon group, A
is an ethylene group, a propylene group or an isopropylene group. n is an integer from 1 to 4. ) is reacted with an organic halide in the presence of an alkaline aqueous solution and a quaternary ammonium salt phase transfer catalyst. ) Method for producing alkylene glycol diethers. 2. The production method according to claim 1, wherein the quaternary ammonium salt is a benzyltrialkylammonium salt or/and a tetrabutylammonium salt. 3 If the alkaline aqueous solution is sodium hydroxide or/
and an aqueous solution of potassium hydroxide. 4. The production method according to any one of claims 1 to 3, wherein the organic halide is an alkyl halide, an alkenyl halide, or an aralkyl halide.