KR101653026B1 - Method for preparing Ethylene glycol - Google Patents

Abstract

Examples of the present invention include a process for producing ethylene glycol in which a mixture containing polyethylene glycol having a weight average molecular weight of 190 g / mol or more and a reactant containing water are reacted to convert it into monoethylene glycol and diethylene glycol Thereby providing a method of converting low-priced polyethylene glycol into a mixture containing monoethylene glycol or diethylene glycol as a high value-added substance.

Description

TECHNICAL FIELD The present invention relates to a method for preparing ethylene glycol,

Examples of the present invention relate to a process for preparing ethylene glycol.

Examples of the ethylene glycol include Methylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG), polyethylene glycol And polyethylene glycol (PEG). Among these, monoethylene glycol occupies the most demand among ethylene glycol, and is used as a raw material for polyester fiber, polyethylene terephthalate (PET) plastic resin and automobile antifreeze.

Generally, as a method for producing such ethylene glycols, a method using ethylene oxide is widely known. For example, ethylene oxide produced by reacting ethylene with oxygen is reacted with water without a catalyst to produce ethylene glycol including monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, and the like. Dialkyl glycol, diethylene glycol, and triethylene glycol, respectively, by passing through a series of distillation columns after removing the water from the mixture through an evaporator. .

However, since the mixture containing polyethylene glycol remaining after recovering monoethylene glycol, diethylene glycol, and triethylene glycol from the ethylene glycol mixture prepared as described above is very limited in use, Or as fuel within the plant.

Conventionally, there has been a method of decomposing under supercritical conditions to utilize such polyethylene glycol. However, these methods have failed to obtain a significant amount of components such as monoethylene glycol and diethylene glycol, Polyethylene glycol is excessively decomposed to generate a large amount of impurities such as acidic compounds. In addition, since the reaction rate is very slow, an additional additive such as a catalyst is required. In this case, the production cost is increased and it is difficult to separate the additives such as catalyst after the reaction. Therefore, A method for producing ethylene glycol which can utilize a mixture of ethylene glycol and ethylene glycol to be used at high efficiency is required.

Examples of the present invention relate to a process for preparing ethylene glycol from which a monoethylene glycol and diethylene glycol can be obtained from a mixture containing polyethylene glycol.

In one example of the present invention, a reaction comprising a polyethylene glycol-containing mixture having a weight average molecular weight of 190 g / mol or more and water is carried out under a gas containing oxygen at a pressure of 40 to 100 bar and a temperature of 150 to 250 ° C And then converting the resulting product into monoethylene glycol and diethylene glycol.

In another example of the present invention, there is provided a process for producing a hydrolysis product of ethylene oxide, Firstly recovering monoethylene glycol and diethylene glycol from the hydrolysis product; And a reaction product comprising a mixture containing polyethylene glycol as a filtrate in the primary recovery step and a reaction product comprising reacting the reaction product at a pressure of 40 to 100 bar and a temperature of 150 to 250 캜 under a gas containing oxygen to produce monoethylene glycol And converting ethylene glycol to diethylene glycol and diethylene glycol.

The process for producing ethylene glycol according to the examples of the present invention is characterized in that a mixture containing low-priced polyethylene glycol is refined in a mixture containing monoethylene glycol and diethylene glycol as high-value substances You can switch.

Hereinafter, exemplary embodiments of the present invention will be described in more detail. In the following description of the present invention, a detailed description of known general functions or configurations will be omitted.

The process for producing ethylene glycol according to the present invention comprises reacting a reaction product comprising polyethylene glycol-containing mixture having a weight average molecular weight of 190 g / mol or more and water at a pressure of 40 to 100 bar and a pressure of 150 To 250 < 0 > C to convert the polyethylene glycol to monoethylene glycol and diethylene glycol. The examples of the present invention also show that the reaction of converting a mixture containing polyethylene glycol into monoethylene glycol and diethylene glycol is applied to the method of producing ethylene glycol, The creation can be increased.

As used herein, " polyethylene glycol " may mean ethylene glycol having a weight average molecular weight of at least 190 g / mol. That is, in the present specification, the polyethylene glycol does not include monoethylene glycol, diethylene glycol, and triethylene glycol having a weight average molecular weight of less than 190 g / mol. The type of polyethylene glycol is not limited as long as the weight average molecular weight falls within a range of 190 g / mol or more. Examples of the polyethylene glycol include tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, , Octaethylene glycol, or a mixture thereof. The examples of the present invention are not limited to those containing only the polyethylene glycol of the above-mentioned kind. In other examples, as the molecular weight of the polyethylene glycol is increased, the polyethylene glycol is advantageously hydrolyzed, The efficiency of the reaction of converting into glycols and diethylene glycol can be enhanced.

The mixture containing polyethylene glycol is not particularly limited as long as it contains polyethylene glycol. In one example of the present invention, the mixture containing polyethylene glycol may contain triethylene glycol.

The polyethylene glycol-containing mixture may be fed into the reactor to include polyethylene glycol in an amount of greater than 0 and less than or equal to 5 parts by weight based on 100 parts by weight of the total reactants participating in the reaction. However, the concentration of the polyethylene glycol is only an example and is not necessarily limited to the above range. For example, 0.001 to 5 parts by weight, 0.01 to 5 parts by weight, 0.1 to 3 parts by weight, or And polyethylene glycol at various concentrations ranging from 1 to 5 parts by weight. Also, the concentration of polyethylene glycol refers to the concentration based on the total reactant in a state where all the reactants are fed into the reactor in which the reaction proceeds, and does not mean the concentration in the individual solution before being introduced into the reactor.

In one example of the present invention, water may be contained in an amount of 95 wt% or more to less than 100 wt% based on the total reactants in order to increase the conversion efficiency of the reaction. The content of the water is not particularly limited, but may be, for example, 95 wt% or more and 99.9 wt% or less, 95 wt% or more and 99 wt% or less, or 95 wt% or more and 97 wt% or less. When water is contained in such a range, it is advantageous to control the concentration of polyethylene glycol in the reactant, reduce the decomposition of polyethylene glycol into a by-product such as an acidic compound, and react with monoethylene glycol and diethylene It is possible to increase the conversion to low molecular weight ethylene glycols including glycols.

The water content can be appropriately adjusted according to the concentration of polyethylene glycol in the reaction product, and the reaction rate can be appropriately controlled by controlling the concentration of the whole reaction product by controlling the water content. As described above, the concentration of polyethylene glycol means a concentration in a state in which all the reactants are put into the reactor, not the concentration prior to the introduction into the reactor.

The method for producing the polyethylene glycol-containing mixture is not particularly limited, and any suitable method known in the art may be employed. For example, mixtures containing polyethylene glycol may be prepared from ethylene oxide hydrolysis products. In these exemplary methods, monoethylene glycol and diethylene glycol can be firstly recovered from each product, and the filtrate left in the recovery process can be used as a mixture containing polyethylene glycol.

The process for producing ethylene glycol according to the present invention comprises reacting a reaction mixture containing polyethylene glycol and water at a pressure of from 40 to 100 bar and a temperature of from 150 to 250 ° C under an oxygen- have.

There is no limitation on the pressure range as long as it falls within the category of the above reaction conditions, but for example, the pressure may be 40 to 100 bar, 50 to 95 bar or 70 to 95 bar. The reaction temperature is not particularly limited as long as it is included in the above-mentioned range, but may be, for example, 150 to 250 ° C, 170 to 220 ° C or 170 to 200 ° C. When the reaction proceeds within the above-mentioned temperature range, the decomposition rate of polyethylene glycol is increased to increase the conversion, while monoethylene glycol and diethylene glycol are decomposed into byproducts such as formic acid, oxalic acid and glycolic acid Can be prevented. In addition, when the reaction proceeds within the above-mentioned pressure range, the degree of dissolution of oxygen contained in the gas contacting the reactant increases to increase the rate of decomposition reaction of polyethylene glycol, Can be increased.

In one example of the invention, the oxygen-containing gas may comprise, but is not limited to, from 21 vol% to 100 vol% oxygen. When the oxygen is contained in the above range, the concentration of oxygen dissolved in the reaction product under the reaction conditions described above can be increased, and the reaction in which polyethylene glycol is converted into monoethylene glycol and diethylene glycol can be promoted .

In one example of the present invention, the reaction of converting a mixture containing polyethylene glycol to monoethylene glycol and diethylene glycol is carried out in a batch reactor, a semi-batch reactor, A continuous flow reactor, a continuous stirred-tank reactor, a plug flow reactor, and a bubble-column reactor. For example, it is possible to add a mixture containing polyethylene glycol and a reactant containing water to a reactor selected from the above range, and then pressurize and heat the mixture under the reaction conditions according to the present invention. However, The kind of the reactor is not limited.

In one example of the invention, the time for the reaction to proceed can be varied, but not limited, within the range of temperature and pressure conditions according to the present invention. For example, the reaction may be carried out for 1 to 10 hours, in which case it is possible to prevent the increase in the consumption of cost and energy due to the unnecessary progress of the reaction and to prevent the decomposition reaction from occurring excessively, can do.

In one example of the invention, a mixture containing polyethylene glycol and water is reacted with the reaction conditions according to the invention to recover monoethylene glycol and diethylene glycol from the resulting product Step < / RTI > Monoethylene glycol and diethylene glycol may be recovered at the same time or may be recovered through each of the different steps, and all known recovery methods may be used. For example, the product produced after the reaction may be introduced into a distillation column, followed by distillation of monoethylene glycol and diethylene glycol, respectively.

After the step of recovering monoethylene glycol and diethylene glycol from the product formed after the reaction as described above, the remaining filtrate or a condensate or a stream containing the filtrate may be mixed with a mixture containing polyethylene glycol and / And recycling the reactants, including water, to the reactor into which they are introduced. If such a recycle step is additionally included, it is possible to reduce the processing cost by recycling the monoethylene glycol and diethylene glycol and recycling the remaining filtrate, and by bringing the unconverted polyethylene glycol back into the reaction, It is possible to create higher added value. In addition, the method of recirculating the filtrate is not limited, and known methods can be suitably employed.

Another process for preparing ethylene glycol according to the present invention comprises the steps of: preparing a hydrolysis product of ethylene oxide; Firstly recovering monoethylene glycol and diethylene glycol from the hydrolysis product; And a reaction product comprising a mixture containing polyethylene glycol as a filtrate in the primary recovery step and a reaction product comprising reacting the reaction product at a pressure of 40 to 100 bar and a temperature of 150 to 250 캜 under a gas containing oxygen to produce monoethylene glycol And diethylene glycol.

In one example, the step of preparing the ethylene oxide hydrolyzate may be carried out by any method known in the related art from a method for producing ethylene glycol or a method for hydrolyzing ethylene oxide. For example, the step of preparing a typical ethylene oxide hydrolysis product may include a process involving hydrolysis, dehydration and purification distillation of ethylene oxide. In this example, ethylene is reacted with oxygen to produce a product comprising ethylene oxide, carbon dioxide, ethylene, oxygen, and water, and a hydrolysis product is prepared from the product comprising the ethylene oxide. The hydrolyzed ethylene oxide produced by the hydrolysis may be produced, for example, by the reaction of a large amount of water with ethylene oxide in a catalytic process or a non-catalytic process, Glycols, diethylene glycol, some triethylene glycols, and small amounts of polyethylene glycol, and the like. The ethylene oxide hydrolysis product may be subjected to a primary recovery step in which the ethylene oxide hydrolysis product is passed through a continuous distillation column under a pressurized or reduced pressure state to remove excess water and vacuum distillation with monoethylene glycol and diethylene glycol, respectively. In the primary recovery step, the remaining filtrate after recovering the monoethylene glycol and diethylene glycol contains polyethylene glycol. In one example of the present invention, the remaining filtrate, polyethylene glycol, Can be converted into monoethylene glycol and diethylene glycol by reacting the mixture containing the compound with water.

The mixture containing polyethylene glycol is not particularly limited as long as it is prepared from the ethylene oxide hydrolysis product, and may be the same as the mixture containing polyethylene glycol described in the first half of this specification.

In one example of the present invention, by using a mixture containing polyethylene glycol that has undergone a step of recovering monoethylene glycol and diethylene glycol from the ethylene oxide hydrolysis product as described above, monoethylene The side reaction in which a part of glycols and diethylene glycols are decomposed again during the reaction can be greatly reduced, thereby further improving the yield of monoethylene glycol and diethylene glycol.

The step of reacting the reactant containing polyethylene glycol and the water to convert it into monoethylene glycol and diethylene glycol is carried out in such a manner that the concentration of each of the reactants, the reaction temperature, the reaction pressure, the reactor, the reaction time And the like may also be the same as those described in the first half of this specification.

In one example, a step of recovering monoethylene glycol and diethylene glycol from the product formed after the step of reacting and converting the reactant comprising polyethylene glycol-containing mixture and water is further carried out . Further, the step of further recovering monoethylene glycol and diethylene glycol from the product formed after reacting the reactant comprising water and the mixture containing polyethylene glycol as described in the first half of the specification Any of the known recovery methods can be used.

For example, an additional step of recovering monoethylene glycol and diethylene glycol from the product formed after the reaction, according to the examples of the present invention, may be a process wherein the remaining filtrate after recovery is fed back to the reactor . In another example, a further step of recovering the monoethylene glycol and diethylene glycol is to recycle the product formed after the reaction to the recoverer of the step of primarily recovering the ethylene oxide hydrolysis product as described above . In this example, the addition of the equipment can be minimized, the remainder of the filtrate can be recycled to reduce the processing cost, and the unconverted polyethylene glycol can be added back into the reaction to create higher added value. In another example, the additional step of recovering monoethylene glycol and diethylene glycol may be a method of recovering the product produced after the reaction by transferring the product to an independent recovery device not previously used.

In the above examples, the method of performing the recovering step can not be employed in a variety of ways depending on the utility of the collection facility. For example, the method of moving the product or the filtrate to another apparatus, the type of the recovering apparatus, and the like are not limited, and known methods can be appropriately employed.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples. However, those skilled in the art will appreciate that the present invention is not limited thereto It will be appreciated that other variations and equivalent embodiments are possible. That is, the true technical protection scope of the present invention is not limited by the following embodiments, but should be determined by the technical idea of the appended claims.

Example  One

Water was added to a mixture containing tetraethylene glycol and tetraethylene glycol in a 300 ml high-pressure batch reactor to obtain a mixture containing 0.83% by weight of tetraethylene glycol, 3% by weight of triethylene glycol Was adjusted to be 0.24% by weight.

Air containing 21% of oxygen was introduced into the reactor into which the mixture was introduced, and the reaction was carried out at a temperature of 170 캜 and a pressure of 40 bar for 5 hours.

Example  2

The procedure of Example 1 was repeated except that the pressure was 50 bar.

Example  3

The same procedure as in Example 1 was carried out except that the pressure was increased to 92 bar.

Example  4

The same procedure as in Example 1 was carried out except that the pressure was adjusted to 40 bar and the temperature was adjusted to 190 캜.

Comparative Example  One

A 300 ml high pressure batch reactor was charged with a mixture comprising triethylene glycol and tetraethylene glycol. The concentration of the mixture was adjusted so that the concentration of triethylene glycol was 8.04% by weight and the concentration of tetraethylene glycol was 2.00% by weight.

The reactor charged with the mixture was subjected to a reaction at a temperature of 150 ° C and a pressure of 30 bar for 5 hours.

Comparative Example  2

The procedure of Comparative Example 1 was repeated except that the concentration of triethylene glycol was adjusted to 0.24% by weight and the concentration of tetraethylene glycol was adjusted to 0.83% by weight.

Comparative Example  3

The same procedure as in Comparative Example 2 was carried out except that the pressure was 5 bar.

Comparative Example  4

The reaction was carried out in the same manner as in Comparative Example 2 except that the pressure was 1 bar and the reaction was conducted at 100 占 폚.

Experimental Example  1: polyethylene Glycoll  Conversion rate and Monoethylene glycol  And Diethylene glycol Generation rate  evaluation

In order to investigate the conversion of polyethylene glycol to the production methods of Examples 1 to 4 and Comparative Examples 1 to 4, Gas Chromatography analysis of the products after the pressurization and heating reaction was carried out.

The GC analysis instrument was Hewlett-Packard 5890 series Ⅱ. The analysis conditions were as follows.

-Detector: FID

-Capillary column: HP-FFAP 30 mX032 mm x 0.25 m

-Column flow: 1.2 ml / min

-Oven temperature: 40 占 폚, 3 min? 15 占 min? 210 占 폚, 11 min

Based on the above analysis results, the production rates of triethylene glycol and polyethylene glycol conversions and monoethylene glycol and diethylene glycol were evaluated and are shown in Tables 1 and 2 below.

(formula)

(TEG) conversion (%) of triethylene glycol = (A / B) X 100

A: The GCarea% of the reduced TEG after the pressurization and heating reaction.

B: GCarea% of TEG before the pressurization and heating reaction.

(PEG) conversion (%) of polyethylene glycol = (A / B) X 100

A: GCarea% of reduced PEG after pressurization and heating reaction

B: GCarea% of PEG before pressurization and heating reaction

(MEG) production ratio (%) of monoethylene glycol = (A / B) X 100

A: The GCarea% of the MEG produced after the pressurization and heating reaction

B: The GCarea% of MEG before the pressurization and heating reaction.

(DEG) production ratio (%) of diethylene glycol = (A / B) X 100

A: GCarea% of DEG produced after the second step

B: GCarea% of DEG before the second step

TEG Conversion Rate (%) PEG conversion (%) Example 1 1.21 14.52 Example 2 6.61 19.33 Example 3 13.33 23.15 Example 4 6.19 20.60 Comparative Example 1 0.12 1.23 Comparative Example 2 0.05 0.10 Comparative Example 3 0.00 0.00 Comparative Example 4 0.00 0.00

MEG generation rate (%) DEG Conversion Rate (%) Example 1 23.01 10.21 Example 2 7.12 3.61 Example 3 2.02 0.15 Example 4 5.00 1.21 Comparative Example 1 0.05 0.02 Comparative Example 2 0.00 0.00 Comparative Example 3 0.00 0.00 Comparative Example 4 0.00 0.00

As shown in Tables 1 and 2, in the examples performed by the method according to the present invention, the yields of monoethylene glycol and diethylene glycol were high. On the other hand, in the case of Comparative Examples 1 and 2 carried out at a pressure lower than the range of the pressure according to the present invention, lower polyethylene glycol conversion and lowering of the content of monoethylene glycol, diethylene glycol Comparative Example 3 in which the pressure range was significantly lower than the pressure range according to the present invention and Comparative Example 4 in which both the reaction temperature and the reaction pressure were lower than the range according to the present invention showed polyethylene glycol conversion and monoethylene The yield of glycols and diethylene glycol was very low.

Claims (17)

delete delete delete delete delete delete delete delete Preparing a hydrolysis product of ethylene oxide;
Firstly recovering monoethylene glycol and diethylene glycol from the hydrolysis product; And
Reacting the reaction mixture containing polyethylene glycol-containing water and the filtrate in the primary recovery step at a pressure of 40 to 100 bar and a temperature of 150 to 250 캜 under a gas containing oxygen to produce monoethylene glycol ≪ / RTI > and diethylene glycol,
Wherein the polyethylene glycol-containing mixture comprises polyethylene glycol in an amount of greater than 0 and less than or equal to 5 parts by weight based on 100 parts by weight of the total reactants.  The process according to claim 9, further comprising the step of recovering monoethylene glycol and diethylene glycol from the product produced after the step of reacting and converting the reactant comprising polyethylene glycol-containing mixture and water Of ethylene glycol. 11. The method of claim 10, wherein recovering the monoethylene glycol and diethylene glycol to be performed further comprises: And recycled to the recovery device of the primary recovery step. 11. The method according to claim 10, wherein the step of recovering the monoethylene glycol and diethylene glycol to be carried out further comprises a step of recovering the product by transferring the product to an independent recovery device ≪ / RTI > 10. The process for producing ethylene glycol according to claim 9, wherein the mixture containing polyethylene glycol comprises triethylene glycol. delete 10. The method of claim 9, wherein the water comprises from 95% by weight to less than 100% by weight based on the total reactants. 10. The method of producing ethylene glycol according to claim 9, wherein the oxygen-containing gas contains oxygen in an amount of from 21 vol% to 100 vol%. 10. A process according to claim 9, wherein the reaction is carried out in a batch reactor, a semi-batch reactor, a continuous stirred-tank reactor, a plug flow reactor and a bubble column reactor and a bubble-column reactor. < RTI ID = 0.0 > 8. < / RTI >