KR100757007B1 - Method for manufacturing polytetramethyleneetherglycol diester - Google Patents

Abstract

A method for preparing polytetramethylene ether glycol diester is provided to improve the uniformity of physical properties of polytetramethylene ether glycol diester by polymerizing tetrahydrofuran. A method for preparing polytetramethylene ether glycol diester comprises the step of polymerizing tetrahydrofuran in the presence of a carboxylic anhydride by using a catalyst selected from an aluminum silicate-based material such as leached soil, amorphous aluminum silicate, magnesium aluminum hydrosilicate, kaolin, halocite, etc. to prepare polytetramethylene ether glycol diester, wherein a polymerization reactor is divided into a main reactor and an auxiliary reactor and the main reactor and the auxiliary reactor are connected in serial or in parallel.

Description

Method for manufacturing polytetramethylene ether glycol diester {Method for Manufacturing Polytetramethyleneetherglycol diester}

1 is a basic process example of the continuous polymerization of tetrahydrofuran using the main reactor and the sub-reactor according to the present invention

<Brief description of the main parts of the drawing>

10: THF Storage Tank

11: THF pump

12: raw material mixing equipment

13: carboxylic anhydride

14: flow control valve

15: circulation pump

16: heat exchanger

17: main reactor

18: flow control valve

19: flow control valve

20: pressure regulating valve

22: flow control valve

23: flow control valve

24: circulation pump

25: heat exchanger

26: side reactor

27: flow control valve

28: flow control valve

29: pressure regulating valve

30: inline mixer

31: reservoir

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The present invention is a continuous polymerization of tetrahydrofuran (hereinafter referred to as "THF") using a catalyst in the presence of anhydrous carboxylic acid to form polytetramethyleneetherglycol diester (hereinafter referred to as "PTMEG-diester"). The method relates to a process for producing "PTMEG-diester" by continuously polymerizing "THF" in the presence of anhydrous carboxylic acid, and attaching a small side reactor to the main reactor to introduce "THF" for each part of the catalyst layer, or It is to provide an improved method of producing "PTMEG-diesters" of very uniform physical properties by running the main and subreactors in parallel or as necessary in series.

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"PTMEG-diester" is an intermediate of polytetramethyleneetherglycol (hereinafter referred to as "PTMEG") and can be easily converted to "PTMEG" by a known method, and "PTMEG" is made of spandex, artificial leather. It is a very versatile and useful polymer that is used as a main raw material in polyurethanes, thermoplastic polyesters, polyamides, and elastomers.

However, conventionally, such "PTMEG-diesters" are used in the presence of anhydrous carboxylic acid, bleaching earth-based and amorphous aluminum silicate, magnesium aluminum hydrosilicate, kaolin, and kaolin. It has been produced by continuous polymerization using an aluminum silicate-based catalyst such as Haloysite or a catalyst of a compound of another metal. In such a conventional process, the activity is continuously decreased according to the service life of the catalyst. Accordingly, there is an inevitable disadvantage that the physical properties of the "PTMEG-diester" are constantly changing.

As a catalyst for producing "PTMEG-diester" in the presence of anhydrous carboxylic acid,

1.Bleached earth catalysts have been disclosed in US Pat. Nos. 4,198,566, 4,243,799, 5,210,283, 6,362,312, 6,274,700, 7,041,752, and the like.

2. Zeolite catalysts are disclosed in US Pat. Nos. 4,303,782, 5,641,857, and the like.

3. Catalysts using aluminum silicate-based or other similar materials are described in U.S. Pat.Nos. 5,208,385, 5,210,283, 6,069,226, 6,207,793, 6,271,413, 6,455,711 and Japanese Patent Publication JP, 04-277522 A. And JP, 04-306228 A, and Korean Patent Nos. 0219792, 0219793, and the like, which are invented by the present inventors.

4. Other catalysts using metal compounds have been disclosed in US Pat. Nos. 5,149,862, 5,773,648, 6,211,401 and Japanese Patent Publication JP 2001-122957.

In most continuous polymerization processes using these catalysts, there is an inevitable disadvantage in that the activity is continuously decreased with the use of the catalyst, and thus the properties of the "PTMEG-diester" are continuously changed.

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Such "PTMEG-diesters" are prepared by polymerizing "THF" in the presence of anhydrous carboxylic acid in a continuous polymerization method. Conventional continuous polymerization uses aluminum silicate and another metal compound as catalysts. There is an inevitable disadvantage that the activity of the catalyst continuously decreases with the use period and the physical properties of the "PTMEG-diester" continuously change. In order to overcome this, it is necessary to introduce a process for producing an improved "PTMEG-diester" characterized.

It is an object of the present invention to provide a continuous polymerization method and process for producing "PTMEG-diesters" of uniform physical properties, more particularly uniform molecular weight distribution and uniform viscosity.

In order to compensate for the change in the properties of the "PTMEG-diester" which is a disadvantage of the prior art, the reaction time should be increased or the reaction temperature should be increased by increasing the reaction temperature to decrease the change in the physical properties. When the production is reduced, the increase in the reaction temperature decreases the conversion rate and the color is worse, there is a limit to increase the reaction time or increase the reaction temperature.

The present invention provides an improved process for overcoming this, by combining a small subreactor with the main reactor, separating the raw material "THF" from the reactor catalyst layer, preferably from two to four layers, or more preferably. Preferably it is separated into three layers, and put into each part, or by operating in parallel or in some cases in series it is an object to produce a more uniform "PTMEG-diester" of physical properties.

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According to the invention it is possible to produce "PTMEG-diesters" of very uniform physical properties.

In the continuous polymerization process, it is inevitable that the activity of the catalyst decreases as the service life of the catalyst elapses. As the catalyst activity decreases, the molecular weight distribution and viscosity of the "PTMEG-diester" increase. To compensate for this, the reaction time can be reduced by increasing the reaction time or raising the polymerization temperature to increase the reaction rate, but in the case of increasing the reaction time, the yield decreases, and when the reaction temperature is increased, the conversion rate is increased. And chromaticity is worse, there is a limit to increase the reaction temperature.

If the molecular weight distribution and viscosity of the "PTMEG-diester" are not uniform, the physical properties of the spandex may be changed during the production of the spandex, which is the main use of the "PTMEG," and thus, it is difficult to manufacture high-grade spandex. Change is required.
The molecular weight distribution and viscosity of "PTMEG-diester" at the same number average molecular weight are correlated, and uniform viscosity means uniform molecular weight distribution, and hereafter represents molecular weight distribution as viscosity.
In the present invention, it is possible to produce a "PTMET-diester" of uniform physical properties by combining a small side reactor for controlling the physical properties to the main reactor in parallel, and in some cases in series, 'FIG. 'Shows a basic process for explaining the contents of the present invention.
The polymerization of "THF" can be both batch and continuous polymerization, but the continuous polymerization according to the present invention, as shown in the continuous polymerization process of the 'FIG. 1', THF pump ( 11) After acetic anhydride (13) is mixed in the raw material mixing plant (12) with "THF" and carboxylic anhydride in an amount suitable for molecular weight control, the mixture (hereinafter referred to as "raw material") is a flow control valve ( 14) is continuously added to the main reactor 17 of the fixed catalyst filled with the catalyst. The main reactor 17 is filled with a catalyst therein, and is divided into parts into three layers. The reaction contents are continuously removed under an isothermal reaction in which the reaction heat is removed from the heat exchanger 16 of the main reactor using the circulation pump 15 of the main reactor and then circulated to the main reactor 17 to keep the reaction temperature constant. Diester ". At this time, if the "raw material" is dispersed in each of the catalyst bed parts of the main reactor 17 without changing the "raw material" input amount 14 to the main reactor 17, even if the amount of circulation of each part of the reaction time Adjustable Therefore, when it is necessary to adjust the viscosity without changing the amount of production, the flow rate for each part circulated to the main reactor is controlled by using the flow control valves 18 and 19.
As shown in the following formula, the number average molecular weight and molecular weight distribution, "PTMEG-diester" is a mixture of "PTMEG-diester" of various molecular weights (polymerization degree), its number of molecules (∑Ni) and individual molecules Depending on the molecular weight (Mi) of (i), even in the same number average molecular weight, the number of molecules and the molecular weight of each molecule may be changed. As a result, the molecular weight distribution changes and the molecular weight distribution and viscosity have a correlation. Means change. If the input amount of "raw material" into the main and sub-reactors 17 and 26 is not changed, and an appropriate amount of "raw material" is added to each part of the catalyst layer of the reactor, the average reaction time of the "raw material" in contact with the catalyst does not change, but each The reaction time of the "PTMEG-diester" molecule (i) is different, the number of molecules and the molecular weight of each molecule is different according to the reaction time, the molecular weight distribution and the resulting viscosity is changed. In the present invention, "PTMEG-diester" having a relatively uniform physical property is prepared by reducing the width of the molecular weight distribution and the change in viscosity under the number average molecular weight of the same "PTMEG-diester" by adding an appropriate amount of "raw material" for each catalytic layer part of the reactor. can do.

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Mn = ω / ΣNi = ΣMiNi / ΣNi

Molecular weight distribution (D) = Mw / Mn

here,

Mn: number average molecular weight ω: weight of the "PTMEG-diester" sample

i: each molecule of "PTMEG-diester"

ΣNi: total molar number of “PTMEG-diester” samples

Molecular weight of Ni: i Mi: molecular weight of i

Mw: weight average molecular weight

The polymerization reaction is an exothermic reaction. At the beginning of the reaction, hot water or low pressure steam is supplied to the heat exchangers 16 and 25 of the main and sub-reactors to warm up to the reaction temperature. Cooling water is supplied to 25) to continuously remove the heat of reaction.

In the sub-reactor 26, the " raw material " can be added to each part of each catalyst layer using the flow control valves 27 and 28 in the same manner as the main reactor 17 to control the viscosity. That is, the sub-reactor 26 may also be configured by dividing the catalyst layer into three parts, and adding a “raw material” to each part of each layer to adjust the viscosity. &Quot; Raw material " is continuously fed to the fixed catalyst subreactor 26 filled with 1/8 to 1/4 of the amount of catalyst in the main reactor 17, and the reaction contents are used with the circulation pump 24 of the subreactor. After the reaction heat is removed from the heat exchanger 25 of the sub-reactor, the reaction is circulated to the sub-reactor 26 to continuously react under an isothermal reaction to keep the reaction temperature constant. The subreactor 26 produces "PTMEG-diester" in parallel with the main reactor 17, and the pressure in the main reaction and subreaction systems is controlled using pressure control valves 20 and 29.

The "PTMEG-diesters" produced in the main reactor 17 and the subreactor 26 are mixed in the pipeline and transferred to the reservoir 31 via the inline mixer 30. At this time, the physical properties of the mixture is controlled by the sub-reactor 26 by calculating the number average molecular weight and viscosity of the "PTMEG-diester" which should be prepared in the sub-reactor 26 by the following equation. The reaction temperature of &lt; RTI ID = 0.0 &gt;) &lt; / RTI &gt; and the input amount 22 of " raw material " are mixed with &quot; PTMEG-diester &quot; produced in the main reactor 17 to obtain the required number average molecular weight and &quot; PTMEG-diester &quot; Manufacture.

μ2 = [μ3 x (Q1 + Q2)]-(μ1 x Q1)

here,

μ1, μ2: Viscosity (Cp) at 40 ° C. of “PTMEG-diesters” prepared in the main and subreactors.

μ3: viscosity required after mixing (Cp).

Q1, Q2: Production flow rate (kg / Hr) of "PTMEG-diesters" produced in the main and subreactors.

Q2 = Q1 x Mn2 x (Mn3-Mn1) / [Mn1 x (Mn2-Mn3)]

here,

Q1, Q2: Production flow rate (kg / Hr) of "PTMEG-diesters" produced in the main and subreactors.

Mn1, Mn2 : Number average molecular weight of "PTMEG-diester" prepared in main and secondary reactors.

Mn 3: Number average molecular weight required after mixing.

In addition, the relationship between the number average molecular weight and the viscosity of the "PTMEG-diester" produced in the same reactor can be expressed as shown below, by adjusting the viscosity constant (Kμ) uniformly within a certain range in each reactor It can maintain a uniform molecular weight and viscosity in the reactor, it can maintain a very uniform physical properties after mixing.

95 Kμ = Mn / μ ^0.493

here,

Mn: average molecular weight of "PTMEG-diester".

μ: viscosity at 40 ° C.

-Kμ: Viscosity constant, constant if reaction temperature, reaction time and activity of catalyst are constant.

In addition, when the viscosity of the "PTMEG-ester" produced in the main reactor 17 is high and the "PTMEG-ester" produced in the sub-reactor 26 is exceeded, the viscosity of the viscosity controlled by the sub-reactor 26 is exceeded. A series operation of the main reactor 17 and the subreactor 26 in which part or all of the "PTMEG-ester" manufactured in the main reactor 17 is introduced into the subreactor 26 using the flow control valve 23. Adjust it in the way. In some cases, when a part of "PTMEG-ester" produced in the main reactor 17 and an appropriate amount of "raw material" are introduced into the sub-reactor 26 using the flow regulating valve 22, the viscosity is very controlled. Become uniform.

In the case of continuous polymerization using an aluminum silicate catalyst in the presence of acetic anhydride, it is preferable that the reactant circulation is circulated from the top to the bottom, and the circulation amount is 2 to 4 times the volume of the main and subreactors (17, 26) per hour. The amount of is appropriate. In addition, an amount corresponding to 2 to 5% of the amount of the catalyst charged into the main reactor 17 is appropriate for the hourly input amount 14 of the "raw material" to the main reactor 17, and the same amount is produced as "PTMEG-diester". . In consideration of the boiling point of "THF", the reaction proceeds effectively at 20 ° C to 60 ° C, specifically 30 ° C to 55 ° C, and a reaction pressure of less than 6 gauge pressure (kg / cm ² g). Unreacted "THF" is recovered through an unreacted acetic anhydride (carboxylic anhydride) separation process and reused in the polymerization without purification. The "PTMEG-diester" polymerized by the process of the present invention can easily produce PTMEG via a known transetherification reaction.

"PTMEG-diester" produced in the process according to the present invention is represented by the following general formula, wherein n is an integer of 9 to 100, R1 and R2 are each an alkyl or alkyl group having 1 to 4 carbon atoms. Derivatives and may be the same or different from one another.

R1CO-O- (CH2-CH2-CH2-CH2-O) n-COR2

Next, the present invention will be described in detail with reference to the following examples, which are not intended to limit the scope of the present invention. Parts (%) used in the following examples means parts by weight (%).

(Example 1)

After the acid treatment according to Korean Patent No. 0219792, ammonium chloride treatment was used, and the catalyst was calcined at 650 ° C for 10 hours to prepare 96.49% "THF" of 99.8% purity and 3.51% acetic anhydride, and averaged at a reaction temperature of 46.5 ° C. After 16 hours of continuous polymerization, unreacted "THF" was analyzed by distillation at 180 ° C and 5 mbar Abs. The composition of the reactants was "PTMEG-Diacetate" 53% and unreacted "THF" 46.79%. The acetic anhydride was 0.21%, the number average molecular weight of "PTMEG- diacetate" was 1,696 g / g-mol, and the viscosity in 40 degreeC was 795 Cp (viscosity constant 610.3 by the formula K (micro) = Mn / (micro) ^0.493 ). The reactant and the same "THF" and acetic anhydride mixture were added to the small subreactor at a ratio of 10: 1, and the composition was continuously reacted at 46.5 ° C for 1 hour, and the composition was "PTMEG-Diacetate" 54.6 %, Unreacted "THF" 45.24%, unreacted acetic anhydride 0.16%, "PTMEG- diacetate" number average molecular weight was 1,698 g / g-mol, viscosity at 40 ℃ was 768 Cp (viscosity constant 621.5). This means that the viscosity at the same number-average molecular weight (1696) as the initial reactant is equivalent to 766 Cp (Kμ = 621.5 and Mn = 1696 calculated at the equation Kμ = Mn / μ ^0.493 ). It also means improvements.

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(Example 2)

In the same manner as in Example 1, "PTMEG- Diacetate", "THF" and the ratio of the acetic anhydride mixture, the reaction time and the reaction temperature were tested as follows.

division Mixing ratio Reaction time Reaction temperature (℃) Number average molecular weight change Viscosity change Viscosity constant change Acetic anhydride concentration (%) One 20: 1 One 44 +2 -14 5.4 3.56 2 10: 1.5 One 47.5 +5 -57 25.3 3.45 3 10: 1 3 47.5 0 -42 17.4 3.45 4 4: 1 5 47.5 +2 -59 24.2 3.45

In the present invention, in the production of polytetramethylene ether glycol diester by continuously polymerizing tetrahydrofuran using a catalyst in the presence of anhydrous carboxylic acid, tetrahydrofuran is added to each part of the catalyst layer by joining a small side reactor to the main reactor. It is effective to make polytetramethylene ether glycol diesters of very uniform physical properties by operating main and secondary reactors in parallel or as necessary in series.

Claims (5)

delete delete Polymerization of tetrahydrofuran in the presence of anhydrous carboxylic acid using a catalyst selected from a catalyst using aluminum silicate-based materials such as bleached earth and amorphous aluminum silicate, magnesium aluminium hydrosilicate, kaolin, and halosites In preparing the ester, a polymerization reactor is divided into a main reactor and a secondary reactor, and a polytetramethylene ether glycol diester is prepared by using the same in parallel or in series. The method of claim 3, wherein the main reactor divides the catalyst layer into two or four sites, and injects a mixture of tetrahydrofuran and carboxylic anhydride to each site to prepare polytetramethylene ether glycol diester. The method of claim 3, wherein the sub-reactor divides the catalyst layer into two or four sites and adds a mixture of tetrahydrofuran and carboxylic anhydride to each site to prepare polytetramethylene ether glycol diester.

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