KR20200065724A - Improved method for producing polyoxyalkylene from hydroxy group-containing raw material - Google Patents

Abstract

The present invention relates to a production method capable of improving the quality of a raw material for a cement admixture by reducing impurities in conventional polyoxyalkylene production; and polyoxyalkylene produced by the method.

Description

IMPROVED METHOD FOR PRODUCING POLYOXYALKYLENE FROM HYDROXY GROUP-CONTAINING RAW MATERIAL}

The present invention relates to a production method capable of improving the quality of a cement admixture raw material by reducing impurities in the conventional production of polyoxyalkylene, and to a polyoxyalkylene produced by the method.

Cement admixtures are widely used in cement compositions such as cement paste, mortar, and concrete. When a cement admixture is used, it is possible to improve the fluidity of the cement composition, and the cement composition can be reduced, thereby improving the strength and durability of the cured product.

Recently, as a cement admixture, a cement admixture containing a polycarboxylic acid-based copolymer as a main component has been proposed, and this cement admixture can exhibit higher water-reducing performance than conventional lignin-based or naphthalene sulfonic acid-based. As a copolymer of a polycarboxylic acid-based admixture, a polycarboxylic acid-based copolymer comprising a structural unit derived from an unsaturated polyalkylene glycol ether (polyoxyalkylene) monomer and a structural unit derived from an unsaturated carboxylic acid monomer is known.

The unsaturated polyoxyalkylene used as a raw material for the admixture is generally prepared by addition polymerization of ethylene oxide to a raw alcohol containing a hydroxyl group.

The production mechanism of unsaturated polyoxyalkylene is as follows (for KOH catalyst).

Impurities of several hundred ppm are present in the raw alcohol, and the impurities are mostly water. In addition, a catalyst is introduced during the production of polyoxyalkylene (when the ethylene oxide is added), and a by-product is generated even when the catalyst is activated (activation or alkoxylation). Most of the by-products produced at this time are water or alcohol depending on the type of catalyst.

Mechanism of by-product formation during catalytic activity (when catalyst KOH and water are produced)

A side reaction in which polyethylene glycol (PEG) is formed by the addition reaction of the by-product and ethylene oxide produced in this way occurs in competition. It is generally called free-PEG because it does not participate in the reaction.

The polyethylene glycol produced in this way acts as a final impurity in the preparation of the admixture. It is known that even if only a small amount is contained, the physical properties of the admixture product are significantly reduced.

Conventional synthesis technology for polyoxyalkylene used as a material for admixture is a problem in which a large amount of polyethylene glycol, which is an impurity, is generated by carrying out an ethylene oxide addition reaction without post-treatment of by-products generated by catalyst activation or included in the raw material. Were holding.

In order to prevent this, there is a method of distilling (reduced pressure) after adding a catalyst together with a raw material, but it was difficult to remove by-products due to azeotropic problems.

CN 103642025 A

The present invention is to provide a polyoxyalkylene prepared by the method and a method for preparing a polyoxyalkylene capable of improving or improving the quality of the admixture raw material by reducing impurities in the conventional polyoxyalkylene production.

In the present invention, in order to solve the above problems, a method for minimizing the production of impurities in the product was sought. In particular, in order to minimize by-products generated by catalyst activation, which may be a source of impurities, a small amount of a catalyst and a raw material are reacted to generate an intermediate, and after additionally adding a catalyst, a material that becomes a source of impurities, such as water or Introduced the process of removing alcohol to solve the problems of the existing prior art.

The present invention

(a) first reacting ethylene oxide with a hydroxy group-containing raw material in the presence of a first amount of catalyst to produce an intermediate having a molecular weight of 200 to 600,

(b) additionally adding a second amount of catalyst to the intermediate,

(c) removing by-products, and

(d) A method for producing polyoxyalkylene, comprising the step of reacting ethylene oxide secondary addition.

In addition, the present invention provides a polyoxyalkylene produced by the above production method.

Unlike the prior art, the present invention introduces a process of generating an intermediate, adding an additional catalyst, and then dehydrating it under reduced pressure, thereby reducing the amount of the catalyst to be initially input as much as possible to produce a material (eg, water or alcohol) that becomes a raw material for impurities. After the primary suppression and obtaining a boiling point synergistic effect through the formation of an intermediate, the production of polyethylene glycol which is an impurity in the product by effectively removing the substance (for example, water or alcohol) that is a source of impurities secondarily through a dehydration process under reduced pressure Can greatly degrade.

1 is a process flow diagram briefly showing a method for producing polyoxyalkylene according to the present invention.

The production method of polyoxyalkylene according to the present invention

(a) first reacting ethylene oxide with a hydroxy group-containing raw material in the presence of a first amount of catalyst to produce an intermediate having a molecular weight of 200 to 600,

(b) additionally adding a second amount of catalyst to the intermediate,

(c) removing by-products, and

(d) a second addition reaction of ethylene oxide.

The hydroxy group-containing raw material used to prepare polyoxyethylene in the method according to the present invention is 4-hydroxybutyl vinyl ether (HBVE) or hydroxyethyl vinyl ether (HEVE), 1,4-cyclohexanedimethanol mono Vinyl ether (CHDMVE), isobutenol (Isobutenol), isoprenol (Isoprenol), and methanol.

The catalyst may be an alkali metal, an alkali metal oxide, an alkali metal carbonate, an alkali metal hydroxide, or an alkali metal alkoxide, for example, KOH, NaOCH ₃ , Na.

The first amount of catalyst may be added at a rate of 100 ppm to 1000 ppm, or 200 to 500 ppm based on the raw material.

In the method of the present invention, when the amount of the catalyst input in step (a) is less than 100 ppm, reactivity may be lowered, and when it is more than 1000 ppm, the amount of impurities may be excessive.

According to the present invention, it is possible to primarily suppress the production of raw materials of impurities by reducing the amount of the catalyst to be initially injected.

As described above, in the present method, after generating the intermediate, a second amount of catalyst is additionally added.

The second amount of catalyst may be added at a rate of 1200 ppm to 2000 ppm, or 1400 to 1800 ppm based on the raw material.

In the method of the present invention, when the amount of the catalyst input in step (b) is less than 1200 ppm, reactivity may be lowered, and when it is more than 2000 ppm, the amount of impurities may be excessive. In the step (a), ethylene oxide may be added in an amount of 5 to 10 moles, or 7 to 10 moles, compared to 1 mole of the raw material.

The ethylene oxide addition reaction may be performed at a reaction temperature of 120 to 180 °C, or a reaction temperature of 140 to 170 °C, or 150 to 170 °C.

In the reaction of adding ethylene oxide, if the reaction temperature is less than 120°C, reactivity may decrease, and if it exceeds 180°C, there may be an explosion problem due to high reactivity, and heat control of the exothermic reaction may be difficult.

In addition, the ethylene oxide addition reaction may be performed at a reaction pressure of 0.1 to 6 kg/cm ² , or a reaction pressure of 3 to 5 kg/cm ² .

When the ethylene oxide addition reaction is less than 0.1 kg/cm ² , the reactivity may be deteriorated, when it is more than 6 kg/cm ² , there may be an explosion problem, and an exothermic reaction may occur excessively.

The intermediate produced through the primary addition reaction of ethylene oxide may have a molecular weight of 200 to 600, or a molecular weight of 250 to 500, or a molecular weight of 300 to 380. The intermediate is essentially the same as the final product, but is a substance with less ethylene oxide molar number (amount) than the final product.

In the method according to the present invention, it is possible to obtain a boiling point synergistic effect through the production of such an intermediate. Since the difference in boiling point between the intermediate and the by-product (substance that becomes the raw material of the impurity) is greater than the difference in boiling point between the raw material and the by-product, the by-product removal process can be more easily applied.

After addition of the catalyst, a by-product generated when the catalyst is activated may be water or alcohol.

The raw material removal process of such impurities can be carried out by distillation under reduced pressure. The distillation under reduced pressure may be performed under 30 to 50 mmHg for 1 to 2 hours.

After removing the material (for example, water or alcohol) that is a source of impurities through a dehydration process under reduced pressure, secondary ethylene oxide addition reaction is performed. By doing in this way, production of polyethylene glycol as an impurity in the final product can be significantly reduced.

In the step (d), ethylene oxide may be added in an amount of 20 to 115 moles or 30 to 80 moles compared to 1 mole of the raw material.

In addition, for the description of the secondary ethylene oxide addition reaction, refer to the description of the ethylene oxide addition reaction described above.

According to another aspect of the present invention, a polyoxyalkylene produced by the above production method may be provided. The polyoxyalkylene may have Formula 1 below.

[Formula 1]

In the above formula,

R ¹ is an alkylene group having 2 to 10 carbon atoms,

R ² is hydrogen or an alkyl group having 1 to 20 carbon atoms,

m is 2 to 10,

n is 2 to 6,

k is 0 or 1,

l is 1 to 120.

According to an embodiment, in the above formula, m is 2, n is 4, R ¹ is C ₂ H ₄ , l is 20 to 55, and R ² may be H.

In the present invention, polyoxyalkylene as a concrete admixture raw material is mentioned, but the use of polyoxyalkylene is not limited to this, and may be used for other uses such as a surfactant.

Hereinafter, the operation and effect of the invention will be described in more detail through specific examples of the invention. However, this is provided as an example of the invention, and the scope of the invention is not limited in any way.

Example

Example 1

100 g (0.86 mol) of HBVE (4-hydroxybutyl vinyl ether) as a raw material and 0.04 g of NaOCH ₃ as a catalyst were added to the reactor, heated to 150° C. under stirring, and 245 g of ethylene oxide was added to about 160° C. The primary addition reaction of ethylene oxide is performed under the temperature of and a pressure of about 4 kg/cm ² . Thereafter, after lowering the temperature of the reactor to 60° C., 0.16 g of NaOCH ₃ is further added as a catalyst. Distillation under reduced pressure at 20 mmHg for 1 hour at the same temperature to remove by-products. Subsequently, the temperature of the reactor was raised to 150° C., and 1723 g of ethylene oxide was added to conduct unsaturated secondary addition reaction of ethylene oxide under a temperature of about 160° C. and a pressure of about 4 kg/cm ² to produce unsaturated polyoxyalkylene. do.

Example 2

Unsaturated polyoxyalkylene was produced as in Example 1, except that 0.04 g of KOH was added as a catalyst.

Comparative Example 1

100 g (0.86 mol) of HBVE (4-hydroxybutyl vinyl ether) as a raw material and 0.20 g of KOH as a catalyst were added to the reactor, then heated to 150°C under stirring, and 1967.2 g of ethylene oxide was added to about 160°C. Ethylene oxide addition reaction is performed under temperature and a pressure of about 4 kg/cm ² to obtain unsaturated polyoxyalkylene.

The amounts of impurities produced in Examples 1 and 2 and Comparative Example 1 are shown in Table 1 below.

* The amount of impurities produced is based on the weight of the final product.

From Table 1, it can be seen that when the polyoxyalkylene is prepared by the method according to the present invention, the content of impurities is greatly reduced.

Claims (7)

(a) first reacting ethylene oxide with a hydroxy group-containing raw material in the presence of a first amount of catalyst to produce an intermediate having a molecular weight of 200 to 600,
(b) additionally adding a second amount of catalyst to the intermediate,
(c) removing by-products,
(d) a method for producing polyoxyalkylene, comprising the step of reacting ethylene oxide with a secondary addition. The method of claim 1, wherein the first amount of the catalyst is added at a rate of 100 to 1000 ppm based on the raw material. The method of claim 1 or 2, wherein the second amount of catalyst is added at a rate of 1200 to 2000 ppm based on the raw material. The method of claim 1 or 2, wherein in the step (a), ethylene oxide is added in an amount of 5 to 10 moles compared to 1 mole of the raw material. The method of claim 1 or 2, wherein in the step (c), ethylene oxide is added in an amount of 20 to 115 moles compared to 1 mole of raw materials. The method according to claim 1 or 2, wherein the catalyst is selected from the group consisting of alkali metals, alkali metal oxides, alkali metal carbonates, alkali metal hydroxides, and alkali metal alkoxides. The method according to claim 1 or 2, wherein the hydroxy group-containing raw material is 4-hydroxybutyl vinyl ether (HBVE), hydroxyethyl vinyl ether (HEVE), 1,4-cyclohexanedimethanol monovinyl ether (CHDMVE). ), isobutenol, isoprenol and is selected from the group consisting of methanol.

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