MXPA06009959A - Process for the production of a polyester product from alkylene oxide and carboxylic acid - Google Patents

Abstract

A process to produce polyester product from alkylene oxide and carboxylic acid. More specifically this process relates to a process to produce polyethylene terephthalate where terephthalic acid and ethylene oxide are reacted to form a partially esterified terephthalic acid product and then the partially esterified product is further reacted with ethylene glycol to produce polyethylene terephthalate.

Description

PROCESS FOR THE PRODUCTION OF A POLYESTER PRODUCT FROM ALKYLENE OXIDE AND CARBOXYLIC ACID FIELD OF THE INVENTION This invention relates to a process for producing a polyester product from alkylene oxide and carboxylic acid. More specifically, this invention relates to a process for producing polyethylene terephthalate (PET) from ethylene oxide and terephthalic acid (TPA). Even more specifically, this process relates to a process for producing PET by reacting terephthalic acid and ethylene oxide in the presence of a catalyst and a solvent to form a partially esterified terephthalic acid product. The partially esterified terephthalic acid product is further reacted with a minimum amount of ethylene glycol to produce PET. BACKGROUND OF THE INVENTION Thermoplastic polyesters are stepwise growth polymers that are useful when made in high molecular weights. The first step in a common method for producing a polyester or copolyester, such as polyethylene terephthalate, is an esterification or ester exchange step wherein a diacid, typically terephthalic acid, or a diester, typically dimethyl terephthalate, reacts with an appropriate diol, typically ethylene glycol, to give a bis (hydroxyalkyl) ester and some oligomers. Water or alcohol is emitted at this stage and is usually removed by fractional distillation. In accordance with the object of making polyethylene terephthalate and other polyesters, a large amount of patent literature is devoted to describing processes for preparing suitable terephthalic / ethylene glycol mixtures as starting materials. In general, these inventions describe the specific mixing schemes with a solid of purified terephthalic acid and liquid ethylene glycol as starting materials. Additionally, there is a substantial body of literature devoted to producing a purified terephthalic acid in the powder form that is suitable for use in the production of PET. In the present invention, a process for producing polyethylene terephthalate from ethylene oxide and terephthalic acid is provided. The terephthalic acid and the ethylene oxide are reacted to form a partially esterified terephthalic acid product. The partially esterified terephthalic acid product for example is subsequently reacted with ethylene glycol in a conventional polyethylene terephthalic process or through the use of a tube reactor to produce polyethylene terephthalate. The use of ethylene oxide may be a preferred method over the use of ethylene glycol. In addition, less heat input may be required during esterification using ethylene oxide against the use of ethylene glycol. The polycondensation step can be conducted in one or more stages and can be completed with the addition of ethylene glycol, if necessary, in order to increase the proportion and to control the mol ratio. Suitable catalysts and additives can be added before or during the polycondensation. Possible catalysts include compounds based on Sb, Ge, Ti, Al, Sn and Zr or combinations thereof. BRIEF DESCRIPTION OF THE INVENTION It is an object of this invention to provide a process for producing a partially esterified carboxylic acid product by contacting in a reactor zone at least one carboxylic acid with at least one alkylene oxide in the presence of at least one solvent and at least one basic catalyst. It is another object of this invention to provide a process for producing a partially esterified terephthalic acid product by contacting in a reactor zone terephthalic acid and ethylene oxide in the presence of at least one solvent and at least one basic catalyst. . It is another object of this invention to provide a process for producing polyethylene terephthalate by contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of a solvent and a basic catalyst to produce a partially esterified terephthalic product.; and then by reacting the partially esterified terephthalic acid product with ethylene glycol to produce polyethylene terephthalate. In one embodiment of this invention, a process for producing a partially esterified carboxylic acid product is provided. The process comprises contacting in a reactor zone at least one carboxylic acid with at least one alkylene oxide in the presence of at least one solvent and at least one basic catalyst to produce the partially esterified carboxylic acid product.; wherein the alkylene oxide is present in a molar ratio ranging from about 0.5: 1 to less than 1: 1 of alkylene oxide to carboxylic acid. In another embodiment of this invention, a process for producing a partially esterified terephthalic acid product is provided. The process comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence with at least one solvent and at least one basic catalyst to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio ranging from about 0.5: 1 to less than 1: 1 from ethylene oxide to terephthalic acid. In another embodiment of this invention, a process for producing a partially esterified terephthalic acid product is provided. The process comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of at least one solvent and at least one basic catalyst to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio ranging from about 0.8: 1 to 1.2: 1 of ethylene oxide to terephthalic acid. In another embodiment of this invention, a process for producing polyethylene terephthalate is provided. The process comprises: (a) contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of a solvent and a basic catalyst to produce a partially esterified terephthalic acid product; wherein the ethylene oxide is present in less than 1: 1 molar ratio of ethylene oxide to terephthalic acid; (b) reacting the partially esterified terephthalic acid product with ethylene glycol to produce the polyethylene terephthalate.

In another embodiment of this invention, a process for producing a partially esterified terephthalic acid product is provided. The process comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of a xylene, oligomeric polyester or toluene and triethylamine to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio of 0.5: 1 to less than 1: 1 of ethylene oxide to terephthalic acid; wherein the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the ethylene oxide is in a liquid phase; wherein the reactor is operated at a temperature from about 120 ° C to about 280 ° C. In another embodiment of this invention, a process for producing a partially esterified terephthalic acid product is provided. The process comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the present of a xylene, oligomeric polyester or toluene and triethylamine to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio of 0.8: 1 to less than 1: 1 of ethylene oxide to terephthalic acid; wherein the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the ethylene oxide is in a liquid phase; and wherein the reactor is operated at a temperature from about 120 ° C to about 280 ° C. These objectives, and other objectives, will become more apparent to others with ordinary skill in the art after reading this description. DETAILED DESCRIPTION OF THE INVENTION In. One embodiment of this invention provides a process for producing a partially esterified carboxylic acid product. The process comprises contacting in a reactor zone at least one carboxylic acid with at least one ethylene oxide in the presence of a solvent and at least one basic catalyst to produce the partially esterified carboxylic acid product; wherein the alkylene oxide is present in a molar ratio ranging from about 0.5: 1 to less than 1: 1 of alkylene oxide to carboxylic acid. The alkylene oxides are selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide or mixtures thereof. Preferably, the ethylene oxide is ethylene oxide. Suitable carboxylic acids include any chemical compound that contains at least two carboxylic acid groups. For example, the carboxylic acids include aromatic dicarboxylic acids preferably having from 8 to 14 carbon atoms, preferably aliphatic dicarboxylic acids having from 4 to 12 carbon atoms, or preferably cycloaliphatic dicarboxylic acids having from 8 to 12 carbon atoms . Other examples of suitable carboxylic acids include, but are not limited to, terephthalic acid, isophthalic acid, trimellitic acid, naphthalene dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4'-dicarboxylic acid, diphenyl-3,4'-acid dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and mixtures thereof. Suitable solvents include, but are not limited to, toluene, xylene, methyl benzoate, ethyl benzoate, heptane, cyclohexane and other cyclic and acyclic hydrocarbons with 6 to 16 carbon atoms, benzene, methyl ethyl ketone, other ketones with 5 to 16 carbon atoms. to 7 carbon atoms such as methyl isopropyl ketone, 3-pentanone (diethyl ketone), 3,3-dimethyl-2-butanone, ethyl isopropyl ketone, methyl isopropyl ketone, 3-hexanone, 3-heptanone, di-isopropyl ketone, chlorobenzene and other chlorinated aromatic hydrocarbons, and oligomeric polyesters and the like, and mixtures thereof. Preferably, the solvent is oligomeric polyesters, xylene or toluene. A basic catalyst results in a pH greater than 8 when one gram of the catalyst is dissolved in 100 ml of water. Examples of suitable basic catalysts include, but are not limited to, primary, secondary and tertiary amines, benzyltrialkyl ammonium hydroxide, alkyl / aryl ammonium hydroxide salts and tetraalkyl ammonium hydroxide salts. The basic catalyst may be triethylamine, tributylamine, trimethylamine, tripropylamine, tributylamine, diisopropylamine, diisopropylethylamine, tetramethyl ammonium hydroxide, benzyltrialkyl ammonium hydroxide, tetraalkyl ammonium hydroxide or mixtures thereof. Preferably, the basic catalyst is selected from the group consisting of triethylamine and tributylamine. Much more preferably, the basic catalyst is triethylamine. The carboxylic acid, alkylene oxide, solvent and basic catalyst can be charged to the reactor zone separately or mixed in any combination. Preferably, the basic catalyst and the ethylene oxide are added in the presence of the carboxylic acid. For the reactor zone, there are no special limitations in the way of construction. However, the reactor zone is subjected to an arrangement that allows contact of the alkylene oxygen, carboxylic acid and solvent and basic catalyst under the given process conditions. Generally, the reactor zone comprises at least one reactor. Preferably, the reactor zone comprises a plug flow reactor where the final temperature is from about 180 ° C to about 280 ° C in order to obtain the high reaction rates and close to the complete conversion of the ethylene oxide. Byproducts such as diethylene glycol (DEG), can be controlled by the addition of small amounts of water, and the water can be used to ensure the complete reaction of the ethylene oxide. The reaction of the carboxylic acid, alkylene oxide, solvent, and basic catalyst in the reactor zone is conducted at a temperature of about 120 ° C to about 280 ° C. Preferably, the reaction is conducted at a temperature of about 180 ° C to about 280 ° C. Generally the reaction is conducted at a pressure of about 100 psi to about 1500 psi. Preferably, the reaction is conducted at a pressure of about 300 psi to about 1500 psi. Most preferably the reaction is conducted at a pressure of about 500 psi. at approximately 1200 psi. In a preferred embodiment of this invention, the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the ethylene oxide is in the liquid phase. The substantial portion is defined as 90% by weight. The alkylene oxide is present in a molar ratio ranging from about 0.5: 1 to about 1.2: 1 of alkylene oxide to carboxylic acid. In another range the alkylene oxide is present in a molar ratio ranging from about 0.5: 1 to less than 1: 1. In another range, the alkylene oxide is present in a varying molar ratio, from about 0.8: 1 to less than 1: 1. In the embodiment when the ethylene oxide is ethylene oxide and the carboxylic acid is terephthalic acid and the solvent is toluene, the triethylamine is present in a concentration of about 0.5 to about 5 weight percent based on the weight of the terephthalic acid. Preferably, triethylamine is present in a concentration of about 1 to about 5 weight percent. Most preferably, triethylamine is present in a concentration of about 1 to about 3 weight percent. In this embodiment the partially esterified carboxylic acid product is known as a partially esterified terephthalic acid product. The conversion of terephthalic acid to a partially terephthalic acid product is defined as the percent conversion of the acid groups in the terephthalic acid to the ester groups. Typically, the conversion is between about 8% to about 60%. Preferably, the conversion is from about 30% to about 50%. Much more preferably, the conversion is from about 40% to about 50%.

The partially esterified carboxylic acid product can be subsequently used to produce a polyester product. This can be achieved by transferring the partially esterified carboxylic acid product to a conventional type polyester process where esterification and oligomerization can be continued. As used herein, "conventional" process or apparatus with respect to polyester processing refers to a non-tube reactor or process, including, but not limited to, a stirred tank reactor process or apparatus. continuous (CSTR), a reactive distillation process or apparatus, separator, or rectification column or a tank process or apparatus with internal materials, screw or kneader. The partially esterified carboxylic acid product can also be directed to an unconventional tube reactor process' as described in U.S. Patent Application Serial No. 10 / 013,318 filed December 7, 2001 with an application No. 20020137877, incorporated herein by reference. The polyester ester product comprises at least one polyester. Examples of polyesters include, but are not limited to, polyethylene terephthalate (PET) homopolymers and copolymers; homopolymer and polyethylene naphthalate copolymers; homopolymer and copolymers of polyethylene isophthalate; homopolymer and polyethylene succinate copolymers; polyethylene adipate homopolymer and copolymer and ho opolyesters and copolyesters which are usually derived from 1,2-propanediol, and 1,2-butanediol and mixtures thereof. In another embodiment of this invention, a process for producing a partially esterified terephthalic acid product is provided. The process comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of at least one solvent and at least one basic catalyst to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio ranging from about 0.5: 1 to less than 1: 1 of ethylene oxide to terephthalic acid. These components and process steps have been previously described in this description. In another embodiment of this invention, a. process to produce a partially esterified terephthalic acid product. The process involves putting contact in a zone of. terephthalic acid reactor with ethylene oxide. in the presence of a solvent and at least one basic catalyst for producing the partially esterified terephthalic acid product; wherein the ethylene oxide is present in 0.8: 1 to 1.2: 1 molar ratio of ethylene oxide to terephthalic acid. These components and process steps have been previously described in this description. In another embodiment of this invention, a process for producing a partially esterified terephthalic acid product is provided. The process comprises: (a) contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of a solvent and a basic catalyst to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is presented in a molar ratio of about 0.5: 1 to less than 1: 1 of ethylene oxide to terephthalic acid; and (b) reacting the product-of partially esterified terephthalic acid with a diol to produce the polyethylene terephthalate. Step (a) has been previously discussed in this description. Step (b) can be achieved by transferring the partially esterified terephthalic acid product to a conventional PET process wherein the esterification and oligomerization can be continued. As used herein, "conventional" process or apparatus with respect to polyester processing refers to a non-pipe reactor or process, including, but not limited to, a continuous stirred tank reactor process or apparatus. (CSTR), a reactive distillation process or apparatus, separator, or rectification column, or a tank process or apparatus with internal materials, screw, or kneader. Suitable diols for producing copolymers comprise cycloaliphatic diols, preferably having about 6 to about 20 carbon atoms, or aliphatic diols, preferably having about 3 to about 20 carbon atoms. Examples of such diols include but are not limited to ethylene glycol (EG), diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, propane-1,3-diol, butane-1, -diol, pentane-1,5-diol, hexane- 1,6-diol, neopentyl glycol, 3-methylpentanediol-1- (2, 4), 2-methylpentanediol- (1,4), 2,2,4-trimethylpentanediol- (1,3), 2-ethylhexanediol- (1) , 3), 2, 2-diethylpropane-diol- (1,3), hexanediol- (1, 3), 1,4-di- (hydroxyethoxy) -benzene, 2,2-bis- (4-hydroxycyclohexyl) - propane, 2,4-dihydroxy-1,3,3-tetramethyl-cyclobutane, 2, 2,, -tetramethylcyclobutanediol, 2,2-bis- (3-hydroxyethoxyphenyl) -propane, 2, 2-bis- (4) -hydroxypropoxyphenyl) -propane, isosorbide, hydroquinone, BDS- (2, 2- (sulfonylbis) 4,1-phenyleneoxy)) bis (ethanol), and the like, and mixtures thereof. The polyesters can be prepared from one or more of the diols of the above type. Di-acids other than terephthalic acid may be included in the process, such as, but not limited to, isophthalic acid, phthalic acid (or anhydride), 2,6- or 2,7-naphthalene dicarboxylic acid, biphenyldicarboxylic acid and stilbenedicarboxylic acid. These acids can be added at any time during the process. Low levels of other additives may also be included in the process, such as ultraviolet absorbers, colorants, reheating agents, anti-tackifying / antiblocking agents, branching agents, processing aids, antioxidants, acetaldehyde and oxygen scavengers, fillers, and the similar ones. Branching agents are compounds that contain more than two carboxylic acids, more than two alcohol functions or a combination of both alcohol and carboxylic which totals more than two. Some examples of TPE processes are described in U.S. Patents 4,110,316, 4,235,844 and 4,230,818 incorporated herein by reference. In an alternative embodiment of this invention, the partially esterified terephthalic acid product is transferred to a tube reactor where esterification and oligomerization can be continued. The tube reactor process is described in the US application Serial No. 10 / 013,318 filed on December 7, 2001 with a publication # 20020137877 is incorporated herein by reference. Step (b) can be conducted in one of more steps and can be completed with added ethylene glycol. Suitable catalysts and additives can also be added before or during the polycondensation. Typical catalysts are compounds containing antimony (III) or titanium (IV). The ethylene glycol that is not reacted in the polyester product can be recycled to an earlier part of the process. EXAMPLES This invention can be further illustrated by the following examples of the preferred embodiments thereof, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise stated. indicate specifically. Example 1: Use of Different Basic Catalyst: Toluene (400 g), terephthalic acid (40 g) and a basic catalyst were added to a liter Hastelloy autoclave. The autoclave was purged and pressurized to 100 psi with nitrogen. The autoclave was heated to 260 ° C, and the pressure was then adjusted to 500 psi with nitrogen. Ethylene oxide (11.5 g) was added at one time to the autoclave from another pressure vessel which was maintained at 700 psi of nitrogen. The temperature of the reaction was maintained at 260 ° C for 30 minutes to produce the partially esterified terephthalic acid product. Then the partially esterified TPA product was cooled to room temperature. The resulting partially esterified product was filtered and the solid esterified TPA was weighed. Conversions for each of the examples are given in Table 1 and measured by 1H NMR. A 50% conversion of terephthalic acid would mean approximately a 100% yield based on ethylene oxide. TABLE 1 The selection of the basic catalyst has a significant effect on the conversion * of the TPA. The best catalyst for this process would be one that gives the best conversion while providing a low DEG product and low b *. The b * is one of the attributes of three colors measured on an instrument based on spectroscopic reflectance. An XE Ultra Scan Hunter instrument is typically the measuring device. Positive readings signify the degree of yellowness (or absorbance of blue light), while negative readings signify the degree of blueness. In general, tertiary amines (triethylamine, triphenylamine, triethanolamine, diisopropylethylamine, trimethylamine, tributylamine, and dimethyldodecylamine) in the above examples under these conditions give the best results. However, within these, there are clear differences. Trimethylamine, the least hindered amine gives the highest conversion, but also gives high color and SDR. Diisopropylethylamine, the most hindered amine in the group, gives very low conversion and high DEG. Triethanolamine, an amine that contains hydroxyl, also gives color and high DEG. The weakest base in this group, triphenylamine, gives almost no conversion. Moderately impaired aliphatic tertiary amines, triethylamine, tributylamine and dimethyldodecylamine, gave the best results with triethylamine, which is the best complete catalyst under these conditions. The unimpeded primary amine, benzylamine, gave reasonable conversion, but had very high DEG, and the hindered secondary amine, diisopropiamine, gave poor conversion. The base of tertiary ammonium hydroxide, benzyltrimethylammonium dioxide, gave good conversion, but the relatively high SDR. It is stated that the successful catalyst here has to be moderately hindered and clearly basic to give the desired properties of high conversion, low DEG and low b *. Example 2: PET Oligomer Prepared and Converted to Polymer Terephthalic acid (-60 g), toluene (600 g) and triethylamine (1.8 g) were added to a one liter Hastelloy autoclave. The autoclave was purged and pressurized to 500 psi with nitrogen. The autoclave was heated to 200 ° C, and the pressure was then adjusted to 1500 psi with nitrogen. Ethylene oxide (15.7 g) was added at one time to the autoclave from another pressure vessel which was maintained at 1700 psi of nitrogen. The reaction temperature was maintained at 200 ° C for 30 minutes and cooled to room temperature. A solid ester TPA was recovered by filtration. Table 2 shows the yield, conversion, b * and DEG% in mol of the oligomer formulation. TABLE 2 31. 9 grams of esterified oligomer of Example 2.3 were then combined with a catalyst. of titanium tetraisopropoxide. (35 ppm in the final polymer) in 3 g of EG. The mixture was heated by the following sequence: TABLE 3 A second example using Sb as the catalyst was completed using the same steps as shown in Table 3. The antimony oxide was dissolved in EG (3 g) and added to the oligomer. The concentration of antimony in the polymer was calculated to be 250 ppm. The polyethylene terephthalate was produced having the properties shown in Table 4. TABLE 4 Clearly, a high inherent inherent viscosity (IV) PET can be prepared from the partially esterified TPA product produced with ethylene oxide. Examples 3: Use of Different Temperatures, Pressures and Amounts of Et3N: Toluene (400 g) terephthalic acid was added (40 g) and triethylamine a, a liter Hastelloy autoclave.

The autoclave was purged and pressurized with nitrogen. The autoclave was heated to the specified temperature and the pressure was increased to the desired level. Ethylene oxide (approximately 11. 5 g) was added at one time to the autoclave from another pressure vessel. The reaction temperature was maintained for 30 minutes and then the autoclave was cooled to room temperature. The resulting partially esterified TPA product stream was filtered and the solid was weighed. The conversions for each of the examples are given in the table below TABLE 5 Good conversions of the esterified TPA were obtained in this complete range of 150-260 ° C, 1-3% by weight of triethylamine and 500-1500 psi. The highest conversion with this experiment was obtained in the range of 175-200 ° C. At higher triethylamine levels the percent conversion was relatively insensitive to pressure. The most desirable temperatures from the continuation point of view for making the polymer from the oligomer is in the range of 250 to 280 ° C because it is the common range for the anterior part of the PET production process.

Claims (57)

1. CLAIMS 1. A process for producing a partially esterified carboxylic acid product, the process characterized in that it comprises contacting in a reactor zone at least one carboxylic acid with at least one alkylene oxide in the. presence of at least one solvent and at least one basic catalyst to produce the partially esterified carboxylic acid product; wherein the alkylene oxide is present in a molar ratio of about 0.5: 1 a. less than 1: 1 of alkylene oxide to carboxylic acid.
2. 2. The process according to claim 1, characterized in that the alkylene oxide is present in a molar ratio of about 0.8: 1 to less than 1: 1 of alkylene oxide to carboxylic acid.
3. 3. The process according to claim 1 or 2, characterized in that the alkylene oxide is at least one selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide and mixtures thereof.
4. 4. The process according to claim 3, characterized in that the carboxylic acid is at least one selected from the group consisting of terephthalic acid, isophthalic acid, trimellitic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4 acid, 4'-dicarboxylic acid, diphenyl-3,4'-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and mixtures thereof.
5. 5. The process according to claim 1 or 2, characterized in that the oxide, alkylene is ethylene oxide and the carboxylic acid is terephthalic acid.
6. The process according to claim 1, characterized in that the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the alkylene oxide is in the liquid phase.
7. The process according to claim 5, characterized in that the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the ethylene oxide is in the liquid phase.
8. 8. The process according to claim 6, characterized in that the alkylene oxide is. Ethylene oxide and the carboxylic acid is terephthalic acid.
9. 9. The process according to claim 7, characterized in that the reactor is operated at a temperature from about 120 ° C to about 280 ° C.
10. The process according to claim 6, characterized in that the reactor is operated at a temperature of about 120 ° C to about 280 ° C.
11. 11. The process according to claim 7, characterized in that the reactor is operated at a temperature of about 180 ° C to about 280 ° C.
12. 12. The process according to claim 6, characterized in that the reactor is operated at a temperature of about 180 ° C to about 280 ° C.
13. The process according to claims 1, 2, 4, 6, 7, 8, 9, 10, 11 or 12, characterized in that the basic catalyst is selected from the group consisting of benzyltrialkyl ammonium hydroxide, • tributylamine, triethylamine, trimethylamine, tripropylamine, tetraalkyl ammonium hydroxide and mixtures thereof.
14. The process according to claim 3, characterized in that the basic catalyst is selected from the group consisting of tributylamine, triethylamine, trimethylamine, tripropylamine, tetraalkyl ammonium hydroxide and mixtures thereof.
15. 15. The process according to claim 5, characterized in that the basic catalyst is selected from the group consisting of tributylamine, triethylamine, trimethylamine, tripropylamine, tetraalkyl ammonium hydroxide and mixtures thereof.
16. 16. The process according to claim 13, characterized in that the solvent comprises at least one selected from the group consisting of toluene and xylene.
17. 17. The process according to claim 13, characterized in that the solvent comprises at least one oligomeric polyester.
18. 18. The process according to claim 12, characterized in that the basic catalyst is triethylamine.
19. 19. The process according to claim 1, characterized in that the partially esterified carboxylic acid product is subsequently used to produce a polyester product.
20. 20. The process according to claim 1, characterized in that the carboxylic acid is at least one selected from the group consisting of terephthalic acid, isophthalic acid, trimellitic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl- 4,4'-dicarboxylic acid, diphenyl-3,4'-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and mixtures thereof.
21. 21. A process for producing a partially esterified terephthalic acid product, the process characterized in that it comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of at least one solvent and at least one basic catalyst for produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio of about 0.5: 1 to less than 1: 1 of ethylene oxide to terephthalic acid.
22. 22. The process according to claim 21, characterized in that the ethylene oxide is present in 0.8: 1 unless less than 1: 1 molar ratio of ethylene oxide to terephthalic acid.
23. 23. The process according to claim 22, characterized in that the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the ethylene oxide is in the liquid phase.
24. 24. The process according to claim 21, characterized in that the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the ethylene oxide is in the liquid phase.
25. 25. The process according to claim 24, characterized in that the reactor is operated at a temperature of about 120 ° C to about 280 ° C.
26. 26. The process according to claim 23, characterized in that the reactor is operated at a temperature from about 120 ° C to about 280 ° C.
27. 27. The process according to claim 24, characterized in that the reactor is operated at a temperature of about 180 ° C to about 280 ° C.
28. 28. The process according to claim 23, characterized in that the reactor is operated, at a temperature of about 180 ° C to about 280 ° C.
29. 29. The process according to claims 21, 22, 23, 24, 25, 26, 27 or 28, characterized in that the basic catalyst is selected from the group consisting of benzyltrialkyl ammonium hydroxide, tributylamine, triethylamine, trimethylamine, tripropylamine, tetraalkyl ammonium hydroxide and mixtures thereof.
30. 30. The process according to claim 29, characterized in that the solvent 'comprises at least one selected from the group consisting of toluene and xylene.
31. 31. The process according to claim 29, characterized in that the solvent comprises at least one oligomeric polyester.
32. 32. The process according to claim 28, characterized in that the basic catalyst is triethylamine.
33. 33. The process according to claim 21, characterized in that the partially esterified terephthalic acid product is subsequently used to produce polyethylene terephthalate.
34. 34. The process according to claim 21, characterized in that it further comprises reacting the partially esterified terephthalic acid product with a diol to produce polyethylene terephthalate.
35. 35. A process for producing a partially esterified terephthalic acid product, the process characterized in that it comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of a solvent and at least one basic catalyst to produce the product of partially esterified terephthalic acid; wherein the ethylene oxide is present in a molar ratio of about 0.8: 1 to 1.2: 1 of ethylene oxide to terephthalic acid.
36. 36. The process according to claim 35, characterized in that the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the alkylene oxide is in the liquid phase.
37. 37. The process according to claim 36, characterized in that the reactor is operated at a temperature of about 120 ° C to about 280 ° C.
38. 38. The process according to claim 36, characterized in that the reactor is operated at a temperature of about 180 ° C to about 280 ° C.
39. 39. The process according to claim 35, characterized in that it further comprises reacting the partially esterified terephthalic acid product with a diol to produce polyethylene terephthalate.
40. 40. The process according to claims 35, 36, 37, 38 or 39, characterized in that the basic catalyst is selected from the group consisting of benzyltrialkyl ammonium hydroxide, tributylamine, triethylamine, trimethylamine, tripropylamine, tetraalkyl ammonium hydroxide and mixtures thereof.
41. 41. The process according to claim 40, characterized in that the solvent is selected from the group consisting of toluene and xylene.
42. 42. The process according to claim 40, characterized in that the solvent comprises at least one oligomeric polyester.
43. 43. A process for producing polyethylene terephthalate, characterized in that the process comprises: (a) contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of a solvent and a basic catalyst to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio of about 0.5: 1 to less than 1: 1 of ethylene oxide to terephthalic acid; (b) reacting the partially esterified terephthalic acid product with a diol to produce the polyethylene terephthalate.
44. 44. The process according to claim 43, characterized in that the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of the ethylene oxide is in the liquid phase.
45. 45. The process according to claim 43, characterized in that the reactor is operated at a temperature of about 120 ° C to about 280 ° C.
46. 46. The process according to claim 45, characterized in that the reactor is operated at a temperature from about 180 ° C to about 280 ° C.
47. 47. The process according to claim 43, 44, 45 or 46, characterized in that the basic catalyst is selected from the group consisting of benzyltrialkyl ammonium hydroxide, tributylamine, triethylamine, trimethylamine, tripropylamine, tetraalkyl ammonium hydroxide and mixtures thereof. same.
48. 48. The process according to claim 47, characterized in that the solvent is at least one selected from the group consisting of toluene and xylene.
49. 49. The process according to claim 47, characterized in that the solvent comprises at least one oligomeric polyester.
50. 50. The process according to claim 49, characterized in that the basic catalyst is triethylamine.
51. 51. The process according to claim 44, characterized in that the reaction occurs in a tube reactor.
52. 52. The process according to claim 44, characterized in that the diol is selected from the group consisting of ethylene glycol (EG), diethylene glycol, triethylene glycol, 1-cyclohexane-dimethanol, propane-1,3-diol, butane-1, 4- diol, pentane-1,5-diol, hexane-1,6-diol, neopentyl glycol, 3-methylpentanediol- (2,), 2-methylpentanediol- (1,4), 2,2,4-trimethylpentane-diol- ( 1,3), 2-ethylhexanediol- (1, 3), 2, 2-diethylpropane-diol- (1, 3), hexanediol- (1, 3), 1,4-di- (hydroxyethoxy) -benzene, 2 , 2-bis- (4-hydroxycyclohexyl) -propane, -2,4-dihydroxy-1,3,3-tetramethyl-cyclobutane, 2, 2,4-tetramethylcyclobutanediol, 2,2-bis- (3- hydroxyethoxyphenyl) -propane, 2,2-bis- (4-hydroxypropoxyphenyl) -propane, isosorbide, hydroquinone, BDS- (2, 2- (sulfonylbis) 4,1-phenyleneoxy)) bis (ethanol), and mixtures thereof .
53. 53. The process according to claim 44, characterized in that the diol comprises ethylene glycol (EG).
54. 54. A process for reducing a partially esterified terephthalic acid product, the process characterized in that it comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of toluene and triethylamine to produce the product of partially terephthalic acid. esterified, wherein the ethylene oxide is present in a molar ratio of about 0.5: 1 to less than 1: 1 ethylene oxide to terephthalic acid, wherein the reactor zone comprises at least one reactor operated at a pressure such that a substantial portion of ethylene oxide is in a liquid phase, wherein the reactor is operated at a temperature of about 120 ° C to about 280 ° C
55. 55. A process for reducing a partially esterified terephthalic acid product, characterized in that the process comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of toluene and tri ethylamine to produce the partially esterified terephthalic acid product; wherein the ethylene oxide is present in a molar ratio of about 0.8: 1 to less than 1: 1"ethylene oxide to terephthalic acid, wherein the reactor zone comprises at least one reactor operated at a pressure such that a A substantial portion of ethylene oxide is in a liquid phase, and wherein the reactor is operated at a temperature of about 120 ° C to about 280 ° C.
56. 56. A process for producing a partially esterified terephthalic acid product, characterized in that the The process comprises contacting in a reactor zone terephthalic acid with ethylene oxide in the presence of toluene and triethylamine to produce the partially esterified terephthalic acid product, wherein the ethylene oxide is present in a molar ratio of about 0.8: 1. less than 1.2: 1 of ethylene oxide to terephthalic acid, wherein the reactor zone comprises at least one reactor operated at such a pressure and a substantial portion of ethylene oxide is in a liquid phase; and wherein the reactor is operated at a temperature from about 120 ° C to about 280 ° C.
57. 57. The process according to claim 54, 55 or 56, characterized in that it further comprises reacting the partially esterified terephthalic acid product with a diol to produce polyethylene terephthalate.