KR20050094430A - Catalyst complex for catalysing esterification and transesterification reactions and process for esterification/transesterification using the same - Google Patents

Abstract

The present invention relates to a novel catalyst complex for catalysing esterification and trans-esterification reactions, comprising: (i) a polymeric titanium glycolate having the formula [TiO 4(CH2)4]nwherein n = 1 to 200; and (ii) an alkali metal glycolate; wherein the molar ratio of the polymeric titanium glycolate and the alkali metal glycolate is about 1.25:1 to about 100:1, preferably about 1.25:1 to about 10:1; and to a process for esterification of a dicarboxylic acid compound and an dialcoholic compound, followed by polycondensation to form a polyester.

Description

Catalyst complex for catalysing esterification and transesterification reactions and process for esterification / transesterification using the same

The present invention relates to catalyst complexes for esterification and transesterification reactions and to esterification / transesterification methods using the same.

Polyesters and copolyesters are known to represent polymeric materials having a variety of uses. They are preferably dicarboxylic compounds such as dicarboxylic acids, preferably aromatic acids such as terephthalic acid, and dihydroxy compounds such as ethylene glycol in the presence of a catalyst. It is obtained by reaction with.

Thermoplastic polyesters are very important polymeric materials that are produced in commercial quantities in large quantities. Linear thermoplastic polyesters such as polyethylene terephthalate (PET) are used in various forms. For example, they can be used in the form of synthetic fibers, which exhibit excellent resistance to most inorganic acids and excellent resistance to laundry solvents and surfactants. Thermoplastic polyesters are also used in large quantities as molding materials. Such materials are characterized by many desired properties such as hardness, strength, toughness, good chemical resistance and low moisture absorption.

For example, the production of polyesters, such as polyethylene terephthalate, by polycondensation of diols with alkyl or aryl diacids is described in Encyclopaedia of Polymer Science and Engineering, 2nd edition, Vol. 12, John Wiley and Sons, New York. It is well known in the art as described in (1988). Polyethylene terephthalate is generally a low molecular weight prepolymer [bis (hydroxyalkyl) by converting terephthalic acid and ethylene glycol in the presence of what is called a one-stage catalyst adduct or by transesterifying dimethyl terephthalate and ethylene glycol. Esters and oligomers] ([bis (hydroxyalkyl) ester and oligomers]). The prepolymer is then polycondensed by esterification and transesterification reactions to form a high molecular weight polyester. Since the transesterification is inherently a slow reaction, this requires keeping the reactants at elevated temperatures for an extended time, which is accompanied by pyrolysis, and the polycondensation step is generally catalyzed.

However, it is highly desirable to produce polyesters having high molecular weight and low yellowness at as high a speed as possible. Yellowness in polyesters is usually the result of polymer degradation and side reactions that occur during polymerization or down-stream processing. Thus yellowing in the synthesized polymers indicates not only the quality of the polymer produced, but also the processability of the polymer into shapes made for color sensitive applications such as fibers, films and certain cast parts. Although many catalysts for producing high molecular weight polyesters are known, they suffer from insufficiency in conversion, ease of use or the quality of the products produced by them. Antimony-containing compounds are widely used commercially as catalysts which provide a desirable combination of high reaction rate and low color. However, there is a significant need for finding antimony substitutes due to cost concerns and the difficulty of dealing with toxic antimony in ways that will not affect the environment.

Titanium-based compounds were often used to catalyze polycondensation reactions. These catalysts are non-toxic and their reactivity is superior to any of the antimony catalysts, but it has been shown to cause undesirable yellowing of the polymer obtained.

Some patents include methods for making polyesters and copolyesters, wherein titanium compounds and alkali metal compounds are used as catalysts. WO 98/56848 describes corecipitates as polycondensation catalysts. DE 195 13 056 A1 describes catalysts based on titanium dioxide or titanate compounds as precipitates. In addition, Japanese Patent Application No. 52148953 describes the production of polyesters by the use of specific complexes comprising titanium as a catalyst in the presence of alkali metal compounds.

Pages 29-33 of Textile Praxis International 1, 1989 describe that catalysts containing equal molar amounts of titanium glycolate and alkali metalglycolates lead to polyesters of insufficient molecular weight. have.

It is therefore a first object of the present invention to catalyze esterification and transesterification reactions, overcoming the disadvantages mentioned in the prior art, in particular with improved polyester properties such as reduced yellowing coloration and increased molecular weight and the like. To provide a catalyst for synthesizing polyester at low catalyst concentration within a short reaction time.

It is a second object of the present invention to provide a process for producing a polyester using the novel catalyst composite.

The first object is,

1) a polymeric titanium glycolate having a structure of Formula 1,

[TiO ₂ (CH ₂ ) ₄ ] _n

In which n is a number from 1 to 200; And

2) an alkali metal glycolate, wherein the molar ratio of the polymeric titanium glycolate and the alkali metal glycolate is in the range of 1.25: 1 to 100: 1, preferably 1.25: 1 to 10: 1. It is achieved by providing a catalyst composite for the esterification / transesterification reaction catalyst characterized in that.

Preferably, the alkali metal of the alkali metal glycolate is sodium, and the chemical formula of glycolate is Na-O-CH ₂ -CH ₂ -OH.

More preferably, the total amount of metal of the catalyst composite in the mixture of esterification constituents, referred to as acid esterification constituents, is 1 to 70 ppm, preferably 10 to 50 ppm.

In order to achieve the second object, in order to prepare polyester using the above catalyst composite, it is usually achieved by first esterifying dicarboxylic acid with diol and then transesterifying. The catalyst complex is active in both. The carboxylic acid compound is a dicarboxylic acid of the formula HOOC-R-COOH, wherein R is a linear or branched alkylen group, arylene group arkenylene group ( alkenylen group) or a combination thereof.

Preferably R has 2 to 30, more preferably 4 to 15 carbon atoms.

Further, the carboxylic acid compound may include terephthalic acid, isophthalic acid, naphthalenic diacid, succinic acid, adipic acid, phthalic acid, and glue. It is preferably selected from the group consisting of tartaric acid (glutaric acid), oxalic acid, maleic acid and combinations thereof.

Most preferably, the carboxylic acid compound is terephthalic acid.

It is also preferred that the carboxylic acid compound is an oligomer having repeating units derived from carboxylic acid.

The alcoholic compound is alkylene glycol of the formula of HO-R'-OH, polyalkylene glycol of the formula of HO- [R "-O-] _n- H, or a combination thereof, wherein R 'is 2 to 10, preferably a linear or branched alkylene group having 2 to 4 carbon atoms, wherein R ″ is the same or different and is linear or branched, having 1 to 10, preferably 1 to 5 carbon atoms Alkylene group.

Further, the alcoholic compound may be ethylene glycol, propylene glycol, isopropylene glycol, butylene glycol, 1-methyl propylene glycol, 1-methyl propylene glycol, It may be selected from the group consisting of pentylene glycol, neopentylene glycol (neopentylene glycol) and combinations thereof.

In addition, in another specific embodiment, it is preferred that the process is carried out at a temperature of 150 to 500 ° C., preferably 250 to 300.

In another specific embodiment, the method is carried out under a pressure of 0.001 to 10 atmospheres.

Furthermore, the molar ratio of the alcoholic compound to the carboxylic acid compound may be in the range of 0.1: 1 to 10: 1, preferably 1: 1 to 3: 1.

The catalyst is referred to as the acid esterification component and is preferably present in the range of 1 to 70 ppm, preferably 10 to 50 ppm of the esterification components.

More advantageously, the process can be used for the preparation of polyethylene terephthalate.

Surprisingly, it has been found that the catalyst composites according to the invention can form polyesters in high yields within a short reaction time. Moreover, the catalyst composite according to the present invention prevents undesirable sulfur change of the formed polyester. The molecular weight of the polyester obtained falls within a higher range than for the antimony-derived catalyst composites and is therefore more suitable for industrial applications. Moreover, much higher molecular weights are obtained in the present invention than in the prior art (pages 29-33 of Textile Praxis International 1, 1989). In addition, only low catalyst concentrations are needed, so the total metal content in the polymer is low.

Polymeric titanium glycolate as the catalyst composite of the present invention has a structure of formula (2).

Wherein n is a number from 0 to 200.

The polymeric titanium glycolate insoluble in ethylene glycol may be dissolved by adding an alkali metal glycolate to form a complex between the titanium glycolate and the alkali metal glycolate. This catalyst composite can be used in solution or as a solid in the preparation of polyesters or copolyesters.

For example, the polymeric titanium glycolate may be prepared by converting titanium butylate and ethylene glycol. The alkali metal glycolate may be prepared by dissolving an elemental alkali metal in ethylene glycol. Titanium glycolate as a polymeric compound cannot be dissolved in ethylene glycol. By adding an ethylene glycol solution of an alkali metal glycolate to titanium glycolate, a complex is obtained that can be dissolved in ethylene glycol to obtain a clear catalyst solution. The complex compound may be precipitated by distillation of ethylene glycol, and may be used as a solid like the ethylene glycol solution.

Although the present invention is described in more detail in the following examples, aspects of the invention are not limited by these embodiments.

Example 1 Preparation of Titanium / Sodium Glycolate

1.1 Synthesis of Titanium Glycolate

A 500 mL three-necked flask with a stirrer, a gas inlet for nitrogen inlet and a distillation tube was charged with 68.0 g (0.2 mol) of titanium butyrate and 124.2 g (2.0 mol) of ethylene glycol. This clear solution was mixed by stirring for 5 minutes. The mixture was heated to 160 ° C. (temperature of the oil bath) while flowing nitrogen slowly. During heating, a white solid begins to precipitate. The n-butyl alcohol formed during the reaction was distilled off. The reaction time is about 9 hours. It is sometimes necessary to heat the temperature of the oil bath to 180 ° C. in order to obtain 59.3 g (0.8 mole) of the theoretical amount of n-butyl alcohol. The flask was sealed with a stopper and the reaction mixture was cooled overnight. 100 ml of ethyl acetate was added to the mixture and stirred for 5 minutes. The solid was filtered off through G3 frit and washed with 50 ml of ethyl acetate. The product was dried over phosphorus pentoxide in a desiccator and then dried at 60 ° C. under vacuum (0.1 mbar) for 3 hours. The yield was 33.5 g (0.199 mol / 99.7%).

1.2 Synthesis of Sodium Glycolate

In a 500 mL, three-necked flask with a stirrer, a high efficiency condenser and a nitrogen gas inlet, 155.18 g of ethylene glycol (MEG) was added and stirred for 15 minutes under the inflow of nitrogen. 11.5 g (0.5 mole) of elemental sodium was cut with a knife and divided into 0.5 g (0.02 mole) pieces. These pieces were carefully added to the MEG. The generation of small amounts of hydrogen gas can be observed. Subsequently, the mixture was carefully heated to 80 ° C. until the total amount of sodium was dissolved. This process can happen very quickly.

1.3 Synthesis of Titanium / Sodium-Glycolate Complex (where the ratio of minute amount is 2: 1)

0.2360 g (1.4 * 10 ^-3 moles) of titanium glycolate and 35 g in a 100 ml Erlenmeyer flask mounted with a ground in a stopper and placed on a magnetic stirrer (0.56 mole) of ethylene glycol was added. The mixture was heated to 120 ° C. and 5.9046 g (0.0590 g corresponds to 0.7 * 10 ⁻³ mol of sodium glycolate) of 1% by weight solution of sodium glycolate in ethylene glycol was added. The suspension turned into a clear solution within about 5 minutes.

Example 2 Synthesis of Polyethyleneterephthalate

In a 2 liter reactor equipped with a stirrer and a torque measurement unit, a predetermined amount of a solution of 778.09 g (4.68 moles) of terephthalic acid, 377.90 g (6.09 moles) of ethylene glycol and a catalyst in ethylene glycol, e.g. The catalyst composite mentioned in Example 1.3 was charged. The temperature was raised to 235 ° C. within 60 minutes and the pressure increased to 9 bar. The pressure was then lowered to atmospheric pressure within 1 hour and 30 minutes and the condensate collected in the flask. After the end of the pre-esterification reaction, the temperature was increased to 260 ° C. within 30 minutes. The temperature was kept at 260 ° C. for 30 minutes and the pressure was reduced to 7 mbar. Subsequently, the temperature was raised to 275 ° C. within 10 minutes and the pressure was lowered below 10 ⁻² mbar. At this time, the measurement of time for polycondensation was started. The temperature was maintained at 275 ° C. until a torque of a given stirrer (7.5 Nm ≡ about 24,000 g / mol) was obtained. After the polycondensation process and granulation, the condensate can be collected using an ice bath. All products were used for analysis of conversion in terms of number average molecular weight and color after completion of crystallization of polyethylene terephthalate via intrinsic viscosity.

The number of examples, the catalyst systems used to polymerize the master batch, the L ^* , a ^* and b ^* color numbers of the polymer product, the time taken for the polycondensation and the number average molecular weights are shown in Table 1 below. Where the CIE color scale (CIE, CIE, Commission Internationale de l'Eclarirage, International commission on Illumination) is as follows;

L ^* (lightness) axis-0 is black, 100 is white

a ^* (red-green) axis-positive values are red; Negative numbers are green and 0 is medium

b ^* (blue) axis-positive values are yellow; Negative numbers are blue and 0 is medium

Example Catalyst-ppm (1) L ^* a ^* b ^* Polycondensation time Molecular weight M _n (g / mol) One 300ppm Sb ₂ Ac ₃ 81.1 -1.9 -0.8 1 hour 39 minutes 23,200 2 300 ppm Ti glycolate 78.4 -1.3 8.7 1 hour 38 minutes 23,100 3 300 ppm Ti glycolate 150 ppm Na glycolate 81.0 -1.6 4.3 1 hour 56 minutes 23,900 4 409 ppm Ti glycolate 40.9 ppm Na glycolate 80.5 -1.1 3.2 1 hour 24 minutes 24,100 5 20ppm Sb ₂ Ac ₃ 81.7 -1.7 -0.2 3 hours 30 minutes 20,600 6 20 ppm Ti glycolate 83.9 -2.1 2.2 2 hours 26 minutes 24,000 7 50 ppm Ti glycolate 40 ppm Na glycolate 83.1 -2.8 4.0 1 hour 25 minutes 24,200 8 40 ppm Ti glycolate 30 ppm Na glycolate 83.7 -2.2 1.2 1 hour 22 minutes 23,500 9 30 ppm Ti glycolate 20 ppm Na glycolate 82.6 -2.6 1.0 1 hour 27 minutes 24,400 10 20 ppm Ti glycolate 10 ppm Na glycolate 85.3 -2.3 0.9 1 hour 34 minutes 24,000  (1) Regarding the esterified component, here terephthalic acid

By using the catalyst system titanium / sodium-glycolate in various compositions (Examples 3, 4, and 7 to 10), 300 ppm of the antimony catalyst typically used for polycondensation (for terephthalic acid, It was confirmed that the time required for polycondensation in the case of 1) was the same. In the case of lower catalyst concentration (Example 5), the polyester obtained as the antimony catalyst had a molecular weight of 20,600 g / mol and the time required for polycondensation was 3 hours 30 minutes, whereas the titanium glycolate catalyst (Example 6) The molecular weight using 2) was 24,000 g / mol and the time taken for polycondensation was shorter (2 hours 26 minutes). Table 1 shows the use of the catalyst composite at lower concentrations (Examples 7 to 10). The time taken for polycondensation was reduced, and the molecular weight was further increased compared to using 300 ppm antimony catalyst. The yellow color in the case of polyethylene terephthalate is very high by using pure titanium glycolate (Example 2, b ^* value 8.7), but using a titanium / sodium-glycolate catalyst system (Example 3, 4 and 7 to 10) or by reducing the catalyst concentration (Example 6).

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said Example, A various deformation | transformation or a change is possible within the scope of the invention as described in a claim, and such a modification or change It goes without saying that the examples also fall within the scope of the present invention.

Therefore, the present invention is effective in providing a catalyst complex for esterification and transesterification reaction and an esterification / transesterification method using the same.

Claims (15)

1) a polymeric titanium glycolate having a structure of Formula 1, [Formula 1] [TiO ₂ (CH ₂ ) ₄ ] _n In which n is a number from 1 to 200; And 2) an alkali metal glycolate, wherein the molar ratio of the polymeric titanium glycolate and the alkali metal glycolate is in the range of 1.25: 1 to 100: 1, preferably 1.25: 1 to 10: 1. A catalyst composite for an esterification / transesterification reaction catalyst, characterized in that. The method of claim 1, Alkali metal of the alkali metal glycolate is sodium, the chemical formula of the glycolate is Na-O-CH ₂ -CH ₂ -OH, characterized in that the catalyst complex for esterification / transesterification reaction catalyst. The method according to claim 1 or 2, Catalysts for esterification / transesterification reaction catalysts, characterized as acid esterification constituents, wherein the total amount of metal in the catalyst complex in the mixture of esterification constituents is 1 to 70 ppm, preferably 10 to 50 ppm. Complex. In the esterification method, The carboxylic acid compound is a dicarboxylic acid of the formula HOOC-R-COOH, Wherein R is a linear or branched alkylen group, an arylene group, an alkenylene group, or a combination thereof, and any one of claims 1 to 3 Using the catalyst complex according to claim 8 for esterifying the carboxylic acid compound and the alcoholic compound. The method of claim 4, wherein R has 2 to 30, more preferably 4 to 15 carbon atoms. The method according to claim 4 or 5, Said carboxylic acid compound is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene diacid, succinic acid, adipic acid, phthalic acid, glutaric acid, oxalic acid, maleic acid and combinations thereof. The method of claim 6, And said carboxylic acid compound is terephthalic acid. The method according to claim 4 or 5, The carboxylic acid compound is an oligomer having repeating units derived from carboxylic acid. The method according to any one of claims 4 to 8, tkdrl alcoholic compounds are alkylene glycols of the formula HO-R'-OH, polyalkylene glycols of the formula HO- [R "-O-] _n- H, or a combination thereof, wherein R 'is 2 to 10, preferably a linear or branched alkylene group having 2 to 4 carbon atoms, wherein R ″ is the same or different and is linear or branched, having 1 to 10, preferably 1 to 5 carbon atoms Characterized in that the alkylene group. The method of claim 9, And the alcoholic compound is selected from the group consisting of ethylene glycol, propylene glycol, isopropylene glycol, butylene glycol, 1-methylpropylene glycol, pentylene glycol, neopentylene glycol and combinations thereof. The method according to any one of claims 4 to 10, Characterized in that the process is carried out at a temperature of 150 to 500 ° C, preferably 250 to 300 ° C. The method according to any one of claims 4 to 11, wherein Characterized in that the method is carried out at a pressure of 0.001 to 10 atmospheres. The method according to any one of claims 4 to 12, The molar ratio of the alcoholic compound to the carboxylic acid compound is in the range of 0.1: 1 to 10: 1, preferably 1: 1 to 3: 1. The method according to any one of claims 4 to 13, Process referred to as acid esterification component, characterized in that the catalyst in the mixture of esterification components is present in the range of 1 to 70 ppm, preferably 10 to 50 ppm. The method according to any one of claims 4 to 14, characterized in that a polyethylene terephthalate is prepared.