KR100973247B1 - Depolymerization of Polytetramethylene glycol - Google Patents

Abstract

The present invention relates to a polytetramethylene glycol depolymerization method, and more specifically, to the polytetramethylene glycol depolymerization method, a tetrahydrofuran is prepared by depolymerizing polytetramethylene glycol at a temperature of 100 to 200 ° C. and a cation exchange resin catalyst. It relates to a polytetramethylene glycol depolymerization method comprising the same.

In the present invention described above, tetrahydrofuran is prepared by depolymerizing polytetramethylene glycol at a low temperature by using a cation exchange resin catalyst, so that the reaction occurs relatively stably when applied to the reaction process, and impurities do not flow into the tetrahydrofuran. The purity of is very high, the cation exchange resin catalyst is not adsorbed in the reactor, the workability of the reactor is significantly improved, the replacement of the cation exchange resin catalyst is also easy, there is no fear of contamination of the cation exchange resin catalyst. In addition, when the cation exchange resin catalyst disposal, there is a remarkable advantage that no separate pretreatment is required and the cost is also reduced.

Polytetramethylene glycol, tetrahydrofuran, depolymerization, cation exchange resin, yield, stability, continuous, batch

Description

Polytetramethylene glycol depolymerization method {Depolymerization of Polytetramethylene glycol}

The present invention relates to a polytetramethylene glycol depolymerization method, and more specifically, to the polytetramethylene glycol depolymerization method, a tetrahydrofuran is prepared by depolymerizing polytetramethylene glycol at a temperature of 100 to 200 ° C. and a cation exchange resin catalyst. It relates to a polytetramethylene glycol depolymerization method comprising the same.

In general, tetrahydrofuran is used in various fields such as a solvent of an organic compound or a raw material of polyol which is a raw material of polyurethane.

In addition, polymers have a range of molecular weights other than a single molecular weight. Polytetramethylene glycol (PTMG) also has a wide range of molecular weights, and may generate other ranges of unwanted molecular weight during manufacture, or polytetramethylene glycol (PTMG) may be mixed therewith. In addition, when treating low molecular weight polytetramethylene glycol (PTMG), such as oligomers, there are thermal decomposition or waste solution treatment to solve this problem, but the most economical method is again tetrahydrofuran (Tetrahydrofuran, THF) ) To recover.

Therefore, a method of preparing tetrahydrofuran (THF) by depolymerizing polytetramethylene glycol (PTMG) has been developed, among which a method using heteropoly acid, sulfuric acid, bleaching earth, silica alumina, and perfluoro Method using metal perfluoroalkylsulfonates, method using kaolin and amorphous silica or X-zeolite catalyst, method using a mixture of zirconia (ZrO ₂ ) and silica (SiO ₂ ) This is known.

Especially. Japanese Laid-Open Patent Publication No. 60-109584 discloses a method of using heteropolyacid as a catalyst for polytetramethylene glycol depolymerization. However, the manufacturing method has a disadvantage in that the activity of the catalyst is lowered due to the deterioration of the catalyst activity due to the water generated in the reaction step. glycol, PTMG) is adsorbed in the reactor, and the economic efficiency is low because of the high operating cost.

US Patent No. 4,115,408 discloses the use of sulfuric acid as a catalyst for polytetramethylene glycol depolymerization. However, the manufacturing method has a problem of corrosion, and also has a problem that must be neutralized during the sewage treatment of sulfuric acid after depolymerization.

In addition, U.S. Patent No. 4,363,924 discloses a method of using bleaching earth as a polytetramethylene glycol depolymerization catalyst. However, the preparation method has problems in activity and lifetime of the catalyst and should be further improved.

Japanese Laid-Open Patent Publication No. 62-257931 discloses a method of using silica-alumina as a polytetramethylene glycol depolymerization catalyst. However, the preparation method also has problems in activity and life of the catalyst and should be further improved.

International Publication No. 95/02625 discloses a method of using a perfluoroalkylsulfonate metal salt as a polytetramethylene glycol depolymerization catalyst. However, the manufacturing method is greatly economical due to the high cost of the catalyst.

German Patent No. 4,410,685 discloses a process using kaolin, amorphous silica, or X-zeolite as polytetramethylene glycol depolymerization catalyst. However, the preparation method also needs to be improved in activity and lifespan.

In addition, Japanese Patent Laid-Open No. 11-269262 discloses a method of using a mixture of zirconia (ZrO ₂ ) and silica (SiO ₂ ) as a polytetramethylene glycol depolymerization catalyst. However, the preparation method should also improve the activity and lifetime of the catalyst.

The manufacturing methods described above do not provide a clear method for applying to the commercialization process, and the yield and operating cost should be improved when the manufacturing methods are applied. Therefore, there is a need for developing a catalyst system for more efficient polytetramethylene glycol (PTMG) depolymerization.

Accordingly, the object of the present invention is to solve the problem of the lack of conventional commercialization process, the yield and the operating cost by solving the problem by adopting the cation exchange resin, the optimum amount of the cation exchange resin and the optimum of the quantitative reaction temperature, high reaction yield. It is an object of the present invention to provide a polytetramethylene glycol depolymerization method for depolymerizing polytetramethylene glycol safely and simply with tetrahydrofuran.

In order to solve the above object, the present invention provides a polytetramethylene glycol depolymerization method, comprising: polytetramethylene glycol depolymerized under a temperature of 100 to 200 ° C. and a cation exchange resin catalyst to produce tetrahydrofuran. A tetramethylene glycol depolymerization method is provided.

In addition, the amount of the cation exchange resin catalyst is characterized in that 1% by weight to 95% by weight.

In addition, the polytetramethylene glycol depolymerization method is characterized in that for producing the tetrahydrofuran through a continuous or batch process using the cation exchange resin.

Since the polytetramethylene glycol depolymerization method of the present invention uses a cation exchange resin catalyst to depolymerize polytetramethylene glycol at low temperature to produce tetrahydrofuran, the reaction occurs relatively stably when applied to the reaction process, and impurities are introduced. Since the purity of the tetrahydrofuran is very high, and the cation exchange resin catalyst is not adsorbed to the reactor, the workability of the reactor is greatly improved, and the cation exchange resin catalyst can be easily replaced to contaminate the cation exchange resin catalyst. There is no worry. In addition, when the cation exchange resin catalyst disposal, there is a remarkable advantage that no separate pretreatment is required and the cost is also reduced.

The present invention is a polytetramethylene glycol depolymerization method, wherein the polytetramethylene glycol depolymerization method includes depolymerizing polytetramethylene glycol at a temperature of 100 to 200 ° C. and a cation exchange resin catalyst to prepare tetrahydrofuran.

Specifically, the polytetramethylene glycol depolymerization reaction is a cation exchange resin having heating and high-efficiency reaction activity in order to produce the polymer tetratetramethylene glycol (PTMG) as a monomer tetrahydrofuran (THF) By using the catalyst of the tetrahydrofuran to significantly improve the yield and purity, the reaction process is maintained stably.

Here, in the polytetramethylene glycol depolymerization method, the polytetramethylene glycol is decomposed by heating in order to generate tetrahydrofuran, which is a product of a depolymerization reaction, that is, a polymer decomposes to form a monomer. At this time, since the reaction temperature is high and the stability is low, the cation exchange resin having a high-efficiency reaction activity is used as a reaction catalyst in the polytetramethylene glycol depolymerization to make the reaction stable and to improve the purity and yield of the produced tetrahydrofuran. do.

Through the reaction of the present invention, tetrahydrofuran having a purity of 99% or more can be obtained.

Polytetramethylene glycol used in the present invention is a polymer chain mixture each independently represented by the following formula (1):

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The polytetramethylene glycol has a n value of 2 to 70, and both ends thereof have a hydroxyl group, and a weight average molecular weight of about 250 to 5,000 is not particularly limited.

In addition, the cation exchange resin used in the present invention is a porous cation exchange resin or a gel type cation exchange resin, both types of ion exchange resin can be used.

The cation exchange resin is a styrene polymer, a copolymer of styrene polymer and divinylbenzene, a methacryl polymer, an acrylic copolymer, and a copolymer of phenol and formaldehyde The functional group is a sulfonate group (Sulonate), carboxylic acid (Carboxylic acid), chlorine ions, hydroxy group, etc. are all used.

In particular, the cation exchange resin is composed of a styrene polymer or a copolymer of a styrene polymer and divinylbenzene, and a functional group preferably includes a sulfonate group.

The cation exchange resin can be easily separated in the reaction system, it is economical to enable a continuous reaction. In addition, there is no need for regeneration or re-concentration, high selectivity of reaction, less by-products, and low corrosiveness of the device, making it easy to select materials.

In addition, impurities are not introduced, and the cation exchange resin catalyst is not adsorbed to the reactor, thereby improving the workability of the reactor, and the replacement of the cation exchange resin catalyst is also easy, so that the cation exchange resin catalyst is not contaminated. In addition, the disposal of the cation exchange resin catalyst does not require a separate pretreatment and cost is reduced.

The degree of crosslinking of the cation exchange resin is directly related to the size of the micropore. The cation exchange resin having large pores and low crosslinking degree has a high reaction rate and thermal stability because large molecules can diffuse into the cation exchange resin. Relatively good. Particle size also affects the reaction rate as much as the degree of crosslinking. Small particles of cation exchange resins have a fast reaction rate, but the particle size should be such that there is no obstacle in operation.

In addition, the amount of the cation exchange resin catalyst is characterized in that 1% by weight to 95% by weight.

When the amount of the cation exchange resin catalyst is less than the above range, the reaction does not proceed, and when it exceeds the above range, there is no meaning because there is no change in yield depending on the cation exchange resin content. That is, for example, since the yield when the content of the cation exchange resin is 95% by weight and the yield when 99% by weight is the same, only the cost is wasted in the process.

   The temperature during the depolymerization reaction of the cation exchange resin used in the present invention is 100 to 200 ℃. If the temperature is less than 100 ℃, the reaction does not occur, if the reaction temperature exceeds 200 ℃ due to the thermal stability of the ion exchange functional group of the cation exchange resin, the catalytic performance is deteriorated, the reaction occurs violently, depolymerization is less, Purity is lowered by the inflow of substances that are not completely depolymerized in the form of steam. In addition, the functional material of the cation exchange resin is incorporated into tetrahydrofuran, which is not preferable.

In addition, the polytetramethylene glycol depolymerization method is characterized in that for producing the tetrahydrofuran through a continuous or batch process using the cation exchange resin.

When the tetrahydrofuran is manufactured in a continuous process using the cation exchange resin, the polytetramethylene glycol is continuously supplied, and thus the cation exchange resin is efficiently used, and the cation exchange resin is used as a batch type. When the tetrahydrofuran is produced by the process, since the storage tank is sufficient, there is an advantage of recovering the produced tetrahydrofuran at a large capacity.

Hereinafter, the present invention will be described in detail by way of examples.

However, the following examples are illustrative of the present invention, and the contents of the present invention are not limited by the following examples. Abbreviations used in the examples are as follows.

THF: Tetrahydrofuran

PTMG: Polytetramethylene glycol

GC: Gas Chromatography

FID: Flame Ionization Detector

Example  One

PTMG used a weight average molecular weight of 1850. Cation exchange resin is a copolymer of porous styrene and divinylbenzene, and the functional group is sulfonate.

At room temperature, the reactor was pressurized and depressurized with nitrogen, 1,000 g of PTMG and 20 wt% of cation exchange resin were added thereto, and the temperature was raised to 120 ° C. THF yield was 200 g / h, the purity was 99.97% by GC / FID confirmed.

Example  2

1,000 g of the same kind of PTMG and 1% by weight of cation exchange resin were added to the same apparatus as in Example 1, and the temperature was raised to 130 ° C. The yield of THF is 32g / h, the purity was confirmed by GC / FID 99.91%.

Example  3

1,000 g of the same kind of PTMG and 10% by weight of the cation exchange resin were added to the same apparatus as in Example 1, and the temperature was raised to 130 ° C. The yield of THF is 90g / h, the purity was confirmed by GC / FID 99.96%.

Example  4

1,000 g of the same kind of PTMG and 20% by weight of the cation exchange resin were added to the same apparatus as in Example 1, and the temperature was raised to 140 ° C. The yield of THF is 940g / h, the purity was confirmed by GC / FID 99.93%

Example  5

1,000 g of the same kind of PTMG and 20% by weight of the cation exchange resin were added to the same apparatus as in Example 1, and the temperature was raised to 200 ° C. The yield of THF is 685g / h, the purity was confirmed by GC / FID 99.79%.

Example  6

1,000 g of the same kind of PTMG and 20% by weight of a cation exchange resin were added to the same apparatus as in Example 1, and PTMG was continuously supplied at a rate of 0.8 kg / h while maintaining the temperature after raising the temperature to 140 ° C. The yield of THF is 912g / h, the purity was confirmed by GC / FID 99.92%.

Comparative example  One

1,000 g of the same kind of PTMG and 20% by weight of cation exchange resin were added to the same apparatus as in Example 1, and the temperature was raised to 90 ° C. As a result, THF could not be obtained, and it was confirmed that the reaction did not occur.

Comparative example  2

1,000 g of the same kind of PTMG and 0.8% by weight of cation exchange resin were added to the same apparatus as in Example 1, and the temperature was raised to 130 ° C. As a result, THF could not be obtained, and it was confirmed that the reaction did not occur.

Comparative example  3

1,000 g of the same kind of PTMG and 20% by weight of the cation exchange resin were added to the same apparatus as in Example 1, and the temperature was raised to 210 ° C. The yield of THF is 430g / h, the purity was confirmed by GC / FID 97.86%.

Comparative example  4

1,000 g of the same kind of PTMG and 10 wt% of X-zeolite were added to the same apparatus as in Example 1, and the temperature was raised to 130 ° C. The yield of THF is 29g / h, the purity was confirmed by GC / FID 99.90%.

Comparative example  5

1,000 g of the same kind of PTMG and 10% by weight of bleached earth were added to the same apparatus as in Example 1, and the temperature was raised to 130 ° C. The yield of THF is 32g / h, the purity was confirmed by GC / FID 99.89%.

Comparative example  6

In the same apparatus as in Example 1, 1,000 wt% of the same kind of PTMG, a mixture of zirconia (ZrO ₂ ) and silica (SiO ₂ ) was added thereto, and the temperature was raised to 170 ° C. The yield of THF is 30g / h, the purity was confirmed by GC / FID 99.69%.

Reaction temperature catalyst input THF  water THF  Generation rate Example 1 120 DEG C Cation Exchange Resin 20 wt% 99.97% 200 g / h Example 2 130 ℃ Cation Exchange Resin 1 wt% 99.91% 32 g / h Example 3 130 ℃ Cation Exchange Resin 10 wt% 99.96% 90 g / h Example 4 140 ℃ Cation Exchange Resin 20 wt% 99.93% 940 g / h Example 5 200 ℃ Cation Exchange Resin 20 wt% 99.79% 685 g / h Example 6 140 ℃ Cation Exchange Resin 10 wt% 99.92% 912 g / h Comparative Example 1 90 ° C Cation Exchange Resin 20 wt% - - Comparative Example 2 130 ℃ Cation Exchange Resin 0.8 wt% - - Comparative Example 3 210 ℃ Cation Exchange Resin 20 wt% 97.86% 430 g / h Comparative Example 4 130 ℃ X-zeolite 10 wt% 99.90% 29g / h Comparative Example 5 130 ℃ Bleached soil 10 wt% 99.89% 32g / h Comparative Example 6 170 ℃ Of ZrO ₂ and SiO ₂
mixture 10 wt% 99.69% 30 g / h

In Example 1 and Example 4, when the 20% by weight of the cation exchange resin is used at a relatively low temperature, the generation rate of THF is very high, and Example 5 has a high generation rate of THF even at a relatively high temperature. However, in Comparative Example 3, the generation rate of THF is large but the purity of THF is slightly low. Comparing Example 2 with Comparative Example 2, it can be seen that the reaction is not started until the amount of the cation exchange resin, which is a catalyst, exceeds 1% by weight. In Example 3 and Example 6, the amount of cation exchange resin as a catalyst is 10% by weight, so it can be seen that the THF production rate is high. It can be seen that in Comparative Example 1, the reaction temperature is low and the depolymerization reaction is not started. Comparative Examples 4 to 6 have a lower THF generation rate than the cation exchange resin catalyst despite the high content of the catalyst.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (3)

A styrene polymer having a sulfonate group or a functional group of chlorine ions as a cation exchange resin catalyst at a temperature of 100 to 200 ° C and a polytetramethylene glycol, a copolymer of styrene polymer and divinylbenzene, a methacryl polymer, an acrylic copolymer, and A polytetramethylene glycol depolymerization method comprising depolymerizing under a catalyst of any one or two or more of copolymers of phenol and formaldehyde to produce tetrahydrofuran. The polytetramethylene glycol depolymerization method according to claim 1, wherein the amount of the cation exchange resin catalyst is 1 wt% to 95 wt%. The polytetramethylene glycol depolymerization method according to claim 1, wherein the polytetramethylene glycol depolymerization method produces the tetrahydrofuran through a continuous or batch process using the cation exchange resin.