KR20230166951A - Manufacturing method of acrylic acid and/or glycolide - Google Patents

Abstract

The present invention provides a method for producing acrylic acid and/or glycolide comprising the step of thermally decomposing a hydroxyalkanoate copolymer in the presence of a catalyst containing tin.

Description

{MANUFACTURING METHOD OF ACRYLIC ACID AND/OR GLYCOLIDE}

The present invention relates to a method for producing acrylic acid and/or glycolide by thermal decomposition of hydroxyalkanoate copolymer.

Plastics are inexpensive and durable materials that can be used to produce a variety of products that find use in a wide range of applications. Accordingly, the production of plastics has been increasing dramatically over the past few decades. Moreover, more than 50% of these plastics are used in single-use, disposable or short-lived products that are discarded within one year of manufacture, such as packaging, agricultural films, single-use consumer goods, etc. Additionally, due to the durability of polymers, significant amounts of plastic end up in landfills and natural habitats around the world, causing increasing environmental problems. Even biodegradable plastics can last for decades, depending on local environmental factors such as levels of UV exposure, temperature, and the presence of appropriate microorganisms.

Therefore, different solutions are being explored to reduce the economic and environmental impacts associated with the accumulation of plastics, from plastic decomposition to plastic recycling.

As an example, polyethylene terephthalate (PET) is the most closed-loop recycled plastic, where PET waste (mainly bottles) is collected, sorted, and recycled. They are pressed into batches, crushed, washed, cut into flakes, melted and extruded into pellets and offered for sale. However, these plastic recycling methods only apply to plastic articles containing only PET, requiring excessive prior sorting.

Additionally, another potential method for recycling plastics is chemical recycling, which allows recovering the chemical components of the polymer. The resulting monomer can be used to re-produce plastic articles after purification, so a chemical regeneration method is needed to recycle it.

The present invention is intended to provide a method for producing acrylic acid and/or glycolide in high yield and purity by thermally decomposing a hydroxyalkanoate copolymer.

According to one embodiment of the present invention, a method for producing acrylic acid and/or glycolide is provided, comprising the step of thermally decomposing a hydroxyalkanoate copolymer in the presence of a catalyst containing tin.

Hereinafter, a method for producing acrylic acid according to specific embodiments of the invention will be described in more detail.

Throughout this specification, unless otherwise specified, “include” or “contains” refers to the inclusion of a certain component (or component) without particular limitation, excluding the addition of other components (or components). cannot be interpreted as

In addition, unless it is specified that the steps constituting the manufacturing method described in this specification are sequential or continuous, or there is another special class, one step and other steps constituting one manufacturing method are performed in the order described in the specification. It is not interpreted as limited. Accordingly, the order of the structural steps of the manufacturing method can be changed within a range that can be easily understood by a person skilled in the art, and in this case, changes that are obvious to those skilled in the art are included in the scope of the present invention.

Throughout this specification, “polylactic acid prepolymer” refers to polylactic acid with a weight average molecular weight of 1,000 to 50,000 g/mol, which is obtained by oligomerizing lactic acid.

Throughout this specification, “poly(3-hydroxypropionate) prepolymer” refers to poly(3-hydroxypropionate) with a weight average molecular weight of 1,000 to 50,000 g/mol obtained by oligomerizing 3-hydroxypropionate. it means.

Additionally, unless otherwise stated herein, the weight average molecular weight of polylactic acid prepolymer, poly(3-hydroxypropionate) prepolymer, and copolymer can be measured using gel permeation chromatography (GPC). Specifically, the prepolymer or copolymer is dissolved in chloroform to a concentration of 2 mg/ml, then 20 μl is injected into GPC, and GPC analysis is performed at 40°C. At this time, the mobile phase of GPC uses chloroform and flows at a flow rate of 1.0 mL/min, the column uses two Agilent Mixed-Bs connected in series, and the detector uses an RI Detector. The Mw value is derived using a calibration curve formed using a polystyrene standard specimen. The weight average molecular weights of the polystyrene standard specimens were 2,000 g/mol, 10,000 g/mol, 30,000 g/mol, 70,000 g/mol, 200,000 g/mol, 700,000 g/mol, 2,000,000 g/mol, 4,000,000 g/mol, and 10,000,000. Nine types of g/mol were used.

In this specification, the terms primary and secondary are used to describe various processes, and the terms are used only for the purpose of distinguishing one component (process) from another component (process).

According to one embodiment of the invention, a method for producing acrylic acid and/or glycolide is provided, comprising the step of thermally decomposing a hydroxyalkanoate copolymer in the presence of a catalyst containing tin.

The present inventors completed the present invention by finding that acrylic acid and/or glycolide, which are recyclable monomers, can be recovered in high purity and yield when hydroxyalkanoate copolymer is thermally decomposed.

In addition, the hydroxyalkanoate copolymer is pyrolyzed and recycled into a recyclable monomer, making it environmentally friendly and economical, and the acrylic acid can be recycled into bio-absorbent resin (SAP) or bio-acrylate.

The method for producing acrylic acid and/or glycolide according to the embodiment includes melting the hydroxyalkanoate copolymer before thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin. Additional steps may be included. That is, the hydroxyalkanoate copolymer can be melted before the thermal decomposition, and this melting process can be performed in the presence of a catalyst containing the tin.

Before thermal decomposition of the hydroxyalkanoate copolymer, residual volatile substances and/or impurities introduced during recycling can be removed by melting. In addition, the melting increases the mobility of the copolymer so that it can be easily introduced into the thermal decomposition reactor, and by taking advantage of this, thermal decomposition can be carried out continuously in the future.

The melting may be performed at a temperature of 150°C or more and 250°C or less. For example, the melting temperature may be 150°C or higher, 180°C or higher, or 190°C or higher, and may be 250°C or lower, 230°C or lower, and 220°C or lower. If the melting temperature is too low, the hydroxyalkanoate copolymer may not melt, and if the melting temperature is too high, the hydroxyalkanoate copolymer may not melt but undergo thermal decomposition, thereby reducing the recovery rate of the monomer, Since there is no process to remove impurities before thermal decomposition, a lot of impurities may flow in, and bumping may occur due to a rapid increase in temperature.

Meanwhile, the melting may be carried out solvent free. For example, when the melting is performed without a solvent, the hydroxyalkanoate copolymer may be melted without being dissolved in the solvent. For example, no solvent other than the hydroxyalkanoate copolymer is added to the reactor, and the temperature applied to the reactor is directly transferred to the hydroxyalkanoate copolymer to melt it. When a solvent is added to the reactor, impurities may be formed in the process of thermally decomposing the hydroxyalkanoate copolymer, and a solvent removal process and an additional impurity removal process are required, making the process complicated or additional A device may be required. Additionally, side reactions may occur during the process of removing the solvent, reducing the recovery rate and purity of monomers. Additionally, there is a disadvantage in that economic efficiency is lowered due to the use of additional solvents.

In the method for producing acrylic acid and/or glycolide according to the above embodiment, the molten hydroxyalkanoate copolymer may be thermally decomposed in the presence of a catalyst containing the tin.

Meanwhile, the thermal decomposition may be carried out at a temperature of 200 ℃ or higher and 400 ℃ or lower, for example, 200 ℃ or higher, 205 ℃ or higher, 210 ℃ or higher, 215 ℃ or higher, 400 ℃ or lower, 350 ℃ or lower. If the thermal decomposition temperature is too low, thermal decomposition of the hydroxyalkanoate copolymer may not be achieved, and if the thermal decomposition temperature is too high, the operating cost of the thermal decomposition process may increase or a large amount of unexpected impurities may be generated.

In addition, the thermal decomposition may be carried out at a pressure of more than 0.01 torr and less than 50 torr, for example, more than 0.01 torr, more than 0.05 torr, more than 0.1 torr, more than 0.5 torr, more than 1 torr, more than 2 torr, more than 4 torr, more than 5 torr. It may be more than torr, less than 50 torr, less than 40 torr, less than 30 torr, less than 20 torr, but it is not limited thereto. The lower the pyrolysis pressure, the easier it may be to separate and recover the finally produced bio-acrylic acid.

The difference between the melting temperature and the thermal decomposition temperature may be 20°C or more and 130°C or less, 30°C or more and 120°C or less, 40°C or more and 110°C or less, 50°C or more and 100°C or less, or 60°C or more and 90°C or less. Due to the small difference between the melting temperature and the pyrolysis temperature, that is, the melting temperature is high and the pyrolysis temperature is low, the continuous pyrolysis process is easy and has an energy saving effect, and bumping, etc. due to the rapid temperature rise between the melting and pyrolysis processes problems can be prevented.

Additionally, the thermal decomposition can be carried out solvent free. For example, when the thermal decomposition is carried out without a solvent, the hydroxyalkanoate copolymer may be thermally decomposed without being dissolved in the solvent. When a solvent is added to the reactor, impurities may be formed in the process of thermally decomposing the hydroxyalkanoate copolymer, and a solvent removal process and an additional impurity removal process are required, making the process complicated or requiring additional equipment. may be needed. Additionally, side reactions may occur during the process of removing the solvent, reducing the recovery rate and purity of monomers. Additionally, there is a disadvantage in that economic efficiency is lowered due to the use of additional solvents.

Additionally, the thermal decomposition may be performed in the presence of a catalyst containing tin. The tin-containing catalyst remains in a solid phase even after the thermal decomposition process, making it easy to separate from the acrylic acid and/or glycolide that is ultimately produced, allowing the acrylic acid and/or glycolide to be recovered at a high recovery rate and with high purity.

Catalysts containing tin include, for example, tin 2-ethylhexanoate (Tin(II) 2-ethylhexanoate), tin 2-methylhexanoate (Tin(II) 2-methylhexanoate), and tin 2-propylhexanoate. Tin(Ⅱ) 2-propylhexanoate, dioctyltin dilaurate, dihexyltin dilaurate, dibutyltin dilaurate, dipropyltin dilaurate (dipropyltin dilaurate), diethyltin dilaurate, dimethyltin dilaurate, dibutyltin bis(lauryl mercaptide), dimethyltin bis( Dimethyltin bis(lauryl mercaptide), Diethyltin bis(lauryl mercaptide), Dipropyltin bis(lauryl mercaptide) lauryl mercaptide)), Dihexyltin bis(lauryl mercaptide), Dioctyltin bis(lauryl mercaptide), Dimethyltin bis(lauryl mercaptide) Dimethyltin bis(isooctylmaleate)), Diethyltin bis(isooctylmaleate), Dipropyltin bis(isooctylmaleate), Dibutyltin bis( Isooctylmaleate) (Dibutyltin bis(isooctylmaleate)), Dihexyltin bis(isooctylmaleate) and Dioctyltin bis(isooctylmaleate) There may be more than one, but it is not limited thereto.

The tin catalyst may be used in an amount of 0.0001 parts by weight or more, 0.0010 parts by weight or more, 0.0100 parts by weight or more, or 0.1000 parts by weight or more, 10 parts by weight or less, 7 parts by weight or less, based on 100 parts by weight of the hydroxyalkanoate copolymer. It can be used in amounts of 5 parts by weight or less, 3 parts by weight or less, and 1 part by weight or less.

The method for producing acrylic acid and/or glycolide may be recycling biodegradable products containing the hydroxyalkanoate copolymer.

The hydroxyalkanoate copolymer is a biodegradable compound, and biodegradable products containing it are not particularly limited as long as they are general products containing biodegradable plastics, but include, for example, plastic bags, fibers, fabrics, food containers, toothbrushes, It may be a film, fishing net, or packaging material. In addition, the method for producing acrylic acid and/or glycolide according to the above embodiment recovers monomers such as acrylic acid and glycolide by thermally decomposing the biodegradable article containing the hydroxyalkanoate copolymer, thereby producing the biodegradable article. can be recycled. In addition, by polymerizing monomers such as acrylic acid and glycolide recovered through thermal decomposition to produce biodegradable plastic, it can be reused as biodegradable products.

In the method for producing acrylic acid and/or glycolide according to the above embodiment, the hydroxyalkanoate copolymer includes a repeating unit derived from 3-hydroxypropionic acid, a repeating unit derived from lactic acid or lactide, and a repeat derived from glycolic acid or glycolide. It may contain two or more types of repeating units selected from the group consisting of units. Additionally, in order to recover acrylic acid and/or glycolide in high purity and high yield, the hydroxyalkanoate copolymer may be 3-hydroxypropionate-lactide copolymer, glycolide-lactide copolymer, or 3- It may be a hydroxypropionate-glycolide copolymer.

In addition, the hydroxyalkanoate copolymer is two types selected from the group consisting of a block containing a repeating unit derived from 3-hydroxypropionic acid, a block containing a repeating unit derived from lactic acid or lactide, and a block containing a repeating unit derived from glycolic acid or glycolide. It may be a block copolymer containing the above blocks. Additionally, in order to recover acrylic acid and/or glycolide in high purity and high yield, the hydroxyalkanoate copolymer may be 3-hydroxypropionate-lactide block copolymer, glycolide-lactide block copolymer, or It may be a 3-hydroxypropionate-glycolide block copolymer.

In the method for producing acrylic acid and/or glycolide according to the above embodiment, the hydroxyalkanoate copolymer is the 3-hydroxypropionate-lactide copolymer,

In the step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing the tin, the 3-hydroxypropionate-lactide copolymer is thermally decomposed in the presence of the catalyst containing the tin to produce acrylic acid. can do.

Additionally, as described above, before the thermal decomposition, the 3-hydroxypropionate-lactide copolymer may be melted.

The 3-hydroxypropionate-lactide copolymer may be a block copolymer obtained by polymerizing polylactic acid prepolymer and poly(3-hydroxypropionate) prepolymer. The 3-hydroxypropionate-lactide copolymer exhibits the excellent tensile strength and elastic modulus characteristics of the polylactic acid prepolymer, while the poly(3-hydroxypropionate) prepolymer has a glass transition temperature (Tg). By increasing flexibility by lowering and improving mechanical properties such as impact strength, the brittleness of polylactic acid due to its poor elongation can be prevented.

The polylactic acid prepolymer may be manufactured by fermentation or polycondensation of lactic acid. The polylactic acid prepolymer may have a weight average molecular weight of 1,000 g/mol or more, or 5,000 g/mol or more, or 6,000 g/mol or more, or 8,000 g/mol or more, and 50,000 g/mol or less, or 30,000 g/mol or less, When it is desired to increase the crystallinity of the block containing repeating units derived from polylactic acid prepolymer in the final manufactured block copolymer, the polylactic acid prepolymer must be greater than 20,000 g/mol, or 22,000 g/mol or more, or 23,000 g/mol. It is preferable to have a high weight average molecular weight of more than or equal to 25,000 g/mol, and less than or equal to 50,000 g/mol, or less than or equal to 30,000 g/mol, or less than or equal to 28,000 g/mol, or less than or equal to 26,000 g/mol.

If the weight average molecular weight of the polylactic acid prepolymer is less than 20,000 g/mol, the polymer crystals are small and it is difficult to maintain the crystallinity of the polymer in the final manufactured block copolymer. If the weight average molecular weight of the polylactic acid prepolymer exceeds 50,000 g/mol, it is difficult to maintain the crystallinity of the polymer. During polymerization, the side reaction rate occurring within the prepolymer chain becomes faster than the reaction rate between polylactic acid prepolymers. Meanwhile, 'lactic acid' used in the present invention refers to L-lactic acid, D-lactic acid, or a mixture thereof.

The poly(3-hydroxypropionate) prepolymer may be manufactured by fermenting or condensation polymerization of 3-hydroxypropionate. The weight average molecular weight of the poly(3-hydroxypropionate) prepolymer is 1,000 g/mol or more, or 5,000 g/mol or more, or 8,000 g/mol or more, or 8,500 g/mol or more, and 50,000 g/mol or less, Alternatively, it may be 30,000 g/mol or less, and when it is desired to increase the crystallinity of the repeating unit derived from the poly(3-hydroxypropionate) prepolymer in the final manufactured block copolymer, the poly(3-hydroxypropionate) The prepolymer has a high weight average molecular weight of more than 20,000 g/mol, or more than 22,000 g/mol, or more than 25,000 g/mol, and less than or equal to 50,000 g/mol, or less than or equal to 30,000 g/mol, or less than or equal to 28,000 g/mol. desirable.

As explained in the polylactic acid prepolymer, if the weight average molecular weight of the poly(3-hydroxypropionate) prepolymer is 20,000 g/mol or less, the polymer crystals are small, making it difficult to maintain the crystallinity of the polymer in the final manufactured block copolymer. It is difficult, and if the weight average molecular weight of the poly(3-hydroxypropionate) prepolymer exceeds 50,000 g/mol, the side reaction rate occurring inside the prepolymer chain is higher than the reaction rate between poly(3-hydroxypropionate) prepolymers during polymerization. becomes faster.

That is, at least one of the polylactic acid prepolymer and the poly(3-hydroxypropionate) prepolymer may have a weight average molecular weight of more than 20,000 g/mol and less than or equal to 50,000 g/mol.

The 3-hydroxypropionate-lactide copolymer is a block copolymer in which polylactic acid prepolymer and poly(3-hydroxypropionate) prepolymer are polymerized, and in the block copolymer, the polylactic acid prepolymer and poly(3 -Hydroxypropionate) The weight ratio of the prepolymer is 95:5 to 50:50, 90:10 to 55:45, 90:10 to 60:40, 90:10 to 70:30, or 90:10 to 80:20. It can be. If too little of the poly(3-hydroxypropionate) prepolymer is included in the polylactic acid prepolymer, brittleness may increase, and the poly(3-hydroxypropionate) prepolymer may increase brittleness. If too much prepolymer is included, the molecular weight may be lowered and processability and heat stability may be reduced.

The 3-hydroxypropionate-lactide copolymer has a weight average molecular weight (Mw) measured using gel permeation chromatography (GPC) of 50,000 to 300,000 g/mol, more specifically 50,000. g/mol or more, 70,000 g/mol or more, or 100,000 g/mol or more, and has a weight average molecular weight of 300,000 g/mol or less, or 200,000 g/mol or less, or 150,000 g/mol or less. If the weight average molecular weight of 3-hydroxypropionate-lactide is too small, the overall mechanical properties may be significantly reduced, and if the weight average molecular weight is too large, the process may be difficult and processability and elongation may be low.

Meanwhile, the lactic acid and 3-hydroxypropionate may be plastic and biodegradable compounds produced from renewable sources by microbial fermentation, and polylactic acid prepolymer and poly(3-hydroxypropionate) formed by polymerizing them The block copolymer containing a prepolymer may also contain a large amount of bio raw materials while exhibiting environmental friendliness and biodegradability.

In addition, acrylic acid produced by thermally decomposing a copolymer containing the bio raw material may also contain a large amount of bio raw material.

Meanwhile, in the process of producing acrylic acid by thermally decomposing the 3-hydroxypropionate-lactide copolymer, the thermal decomposition may be performed at a temperature of 200 ° C. or higher and 350 ° C. or lower, for example, 200 ° C. or higher and 220 ° C. It may be 240 ℃ or higher, 260 ℃ or higher, and may be 350 ℃ or lower, 330 ℃ or lower, 310 ℃ or lower, or 290 ℃ or lower. If the thermal decomposition temperature is too low, thermal decomposition of the hydroxyalkanoate-lactide copolymer may not be achieved, and if the thermal decomposition temperature is too high, many unexpected impurities may be generated.

Additionally, in the thermal decomposition process, acid and phosphonium salt may be added after the tin catalyst is added. As the tin catalyst is added in the thermal decomposition process, the 3-hydroxypropionate-lactide copolymer is thermally decomposed to produce acrylic acid and lactide. After the acrylic acid and lactide are produced by adding the tin catalyst, when the acid and phosphonium salt are added, the lactide is converted to acrylic acid, and finally, only acrylic acid can be produced through a thermal decomposition process.

The acid can play a role in activating the carbonyl group of lactide, and can react with the phosphonium salt to produce acids such as bromic acid and hydrochloric acid, which can cause a ring-opening reaction of lactide and replace the hydroxy group with a halide group. there is.

In addition, the phosphonium salt reacts with the acid to produce acids such as bromic acid and hydrochloric acid, and replaces the hydroxy group of the ring-opening reacted lactide with a halide group to finally produce acrylic acid.

For example, after adding the tin catalyst, after 30 minutes or more, 40 minutes or more, 50 minutes or more, 1 hour or more, or 4 hours or less, 3 hours or less, or 2 hours or less, the acid and phosphonium salt may be added. If the acid and phosphonium salt are added too quickly after the tin catalyst is added, the 3-hydroxypropionate-lactide copolymer is thermally decomposed and the acid and phosphonium salt are added before acrylic acid and lactide are produced. Accordingly, other impurities other than acrylic acid may be generated, and if the acid and phosphonium salt are added after too much time has passed after the tin catalyst is added, the material produced by the thermal decomposition process is exposed to strong heat for a long time, so a side reaction occurs and the desired material is lost. You may not be able to get it.

The acid and the phosphonium salt may be added at the same time, the phosphonium salt may be added after the acid is added, or the acid may be added after the phosphonium salt is added, but is not limited thereto.

The acid is one selected from the group consisting of phosphoric acid, pyrophosphoric acid, metaphosphoric acid, polyphosphoric acid, phosphoric acid anhydride, phosphorous acid, hypophosphoric acid, sulfuric acid, nitric acid, silicic acid, hydrofluoric acid, boric acid, hydrochloric acid, perchloric acid, citric acid, tartaric acid, malic acid, and salts of these acids. It could be more than that.

The acid may be used in an amount of 0.0001 parts by weight or more, 0.0010 parts by weight, 0.0100 parts by weight, or 0.1000 parts by weight or less, 10 parts by weight or less, 7 parts by weight, based on 100 parts by weight of the 3-hydroxypropionate-lactide copolymer. It may be used in an amount of 100 parts or less, 5 parts by weight or less, 3 parts by weight or less, and 1 part by weight or less. If the amount of acid added is too small, it cannot function as an acid catalyst, and if the amount of acid added is too large, side reactions may occur.

The phosphonium salt may be a quaternary phosphonium salt. In addition, the phosphonium salt is, for example, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetraphenylphosphonium bromide, tetraphenylphosphonium chloride, dimethyldiphenylphosphonium bromide, dimethyldiphenylphosphonium chloride, methyl Triphenoxyphosphonium bromide, methyltriphenoxyphosphonium chloride, hexadecyltributylphosphonium bromide, hexadecyltributylphosphonium chloride, octyltributylphosphonium bromide, octyltributylphosphonium chloride, tetradecyltri Hexylphosphonium bromide, tetradecyltrihexylphosphonium chloride, tetrakis(hydroxymethyl)phosphonium bromide, tetrakis(hydroxymethyl)phosphonium chloride, tetraoctylphosphonium bromide, tetraoctylphosphonium chloride, tetramethylphosphonium It may be one or more selected from the group consisting of phonium bromide and tetramethylphosphonium chloride.

The phosphonium salt may be used in an amount of 0.0001 parts by weight or more, 0.0010 parts by weight, 0.0100 parts by weight, 0.1000 parts by weight or more, and 10 parts by weight or less, based on 100 parts by weight of the 3-hydroxypropionate-lactide copolymer. , may be used in amounts of 7 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, and 1 part by weight or less. If the amount of the phosphonium salt added is too small, acids such as bromic acid and hydrochloric acid may not be generated and conversion to acrylic acid may not be achieved, and if the amount of the phosphonium salt added is too large, side reactions may occur or it may be uneconomical.

Additionally, the weight ratio of the acid and phosphonium salt may be 1:0.1 to 10, 1:0.3 to 8, 1:0.5 to 6, 1:1.0 to 5, or 1:1.5 to 3. If the amount of phosphonium salt added compared to the above acid is too small, acids such as bromic acid and hydrochloric acid may not be generated and conversion to acrylic acid may not be achieved. If the amount of phosphonium salt added compared to the acid is too large, side reactions may occur or it is not economical. There is a problem that cannot be resolved.

Additionally, the weight ratio of the tin catalyst and phosphonium may be 1:0.1 to 10, 1:0.3 to 8, 1:0.5 to 6, 1:1.0 to 5, or 1:1.5 to 3.

Through the thermal decomposition, acrylic acid can be recovered through distillation, where the acrylic acid recovery rate is 30% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, for example, 40 to 99.9%. , 50 to 99.9%, 60 to 99.9%, 70 to 99.9%, 80 to 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99% , 90 to 99%, 40 to 97%, 50 to 97%, 60 to 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95% , 70 to 95%, 80 to 95%, or 90 to 95%. The recovery rate may be calculated on a weight basis.

The purity of the acrylic acid is 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, such as 40 to 99.9%, 50 to 99.9%, 60 to 99.9%, 70 to 99.9%, 80 to 90%. 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97%, 50 to 97%, 60 to Can be 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95%, or 90 to 95%. there is.

In the method for producing acrylic acid and/or glycolide according to the above embodiment, the hydroxyalkanoate copolymer is the 3-hydroxypropionate-lactide copolymer,

The step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin,

Preparing lactide by first thermally decomposing the 3-hydroxypropionate-lactide copolymer in the presence of a catalyst containing the tin; And it may include producing acrylic acid by secondary thermal decomposition of the first thermally decomposed hydroxyalkanoate-lactide copolymer.

Additionally, as described above, before the thermal decomposition, the 3-hydroxypropionate-lactide copolymer may be melted. After the 3-hydroxypropionate-lactide copolymer melting step, lactide can be produced by first thermal decomposition of the molten 3-hydroxypropionate-lactide copolymer. Additionally, acrylic acid can be produced by secondary thermal decomposition of the first thermally decomposed 3-hydroxypropionate-lactide copolymer. At this time, the first and second thermal decomposition can be performed under solvent-free conditions as described above.

The 3-hydroxypropionate-lactide copolymer is a block copolymer in which polylactic acid prepolymer and poly(3-hydroxypropionate) prepolymer are polymerized, and when this is first thermally decomposed, lactide is produced from the polylactic acid prepolymer. can be produced, and acrylic acid can be produced from the poly(3-hydroxypropionate) prepolymer when the first thermally decomposed block copolymer is secondarily thermally decomposed.

Meanwhile, in the process of producing lactide by primary thermal decomposition of the 3-hydroxypropionate-lactide copolymer in the presence of the catalyst containing the tin, the primary thermal decomposition is performed at a temperature of 200°C or more and 250°C or less. It can be done at a temperature, for example, 200 ℃ or higher, 210 ℃ or higher, 220 ℃ or higher, 250 ℃ or lower, 240 ℃ or lower, 230 ℃ or lower. If the first thermal decomposition temperature is too low, thermal decomposition of the hydroxyalkanoate-lactide copolymer may not be achieved, and if the first thermal decomposition temperature is too high, many unexpected impurities may be generated.

In addition, the first thermal decomposition may be performed at a pressure of more than 1 torr and less than 50 torr, for example, more than 1 torr, more than 2 torr, more than 4 torr, more than 5 torr, less than 50 torr, less than 40 torr, and less than 30 torr. It may be torr or less, 20 torr or less. If the primary pyrolysis pressure is too low, it may be difficult to recover the produced lactide, and if the primary pyrolysis pressure is too high, a large amount of energy is required, which may reduce economic efficiency. The first thermal decomposition may be performed under a catalyst containing tin.

Additionally, after the first thermal decomposition, the lactide can be separated by reduced pressure distillation. For example, since the first thermal decomposition is carried out under reduced pressure conditions at a pressure exceeding 1 torr, the lactide produced at this time can be recovered through reduced pressure distillation. Additionally, even if the first pyrolysis is not performed under reduced pressure conditions, the lactide can be recovered through distillation.

Acrylic acid can be produced by secondary thermal decomposition of the 3-hydroxypropionate-lactide copolymer remaining after the lactide is recovered.

Meanwhile, in the process of producing acrylic acid by secondary thermal decomposition of the first thermally decomposed hydroxyalkanoate-lactide copolymer, the secondary thermal decomposition may be performed at a temperature of 250 ° C. or higher and 300 ° C. or lower, for example It may be 250°C or higher, 260°C or higher, 270°C or higher, 280°C or higher, and may be 300°C or lower and 290°C or lower. If the secondary pyrolysis temperature is too low, the thermal decomposition of the first pyrolytic 3-hydroxypropionate-lactide copolymer may not occur, making it difficult to recover acrylic acid, and if the secondary pyrolysis temperature is too high, it may be difficult to recover acrylic acid. A lot of impurities may be generated.

The difference between the primary pyrolysis temperature and the secondary pyrolysis temperature may be 20 ℃ or higher and 100 ℃ or lower, for example, 20 ℃ or higher, 30 ℃ or higher, 50 ℃ or higher, 60 ℃ or higher, 100 ℃ or lower, 90 ℃ or higher. It may be below 80°C or below 70°C. If the difference between the first and second pyrolysis temperatures is too small, recovery of the acrylic acid may be difficult, and if the difference between the first and second pyrolysis temperatures is too large, many unexpected impurities may be generated. . Through the secondary thermal decomposition, acrylic acid can be recovered through distillation. At this time, the recovery rate of acrylic acid and lactide is 30% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, for example, 40 to 99.9%, 50 to 99.9%, 60 to 99.9%. , 70 to 99.9%, 80 to 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97% , 50 to 97%, 60 to 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95% , or it may be 90 to 95%. The recovery rate may be calculated on a weight basis.

The purity of the acrylic acid is 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, such as 40 to 99.9%, 50 to 99.9%, 60 to 99.9%, 70 to 99.9%, 80 to 90%. 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97%, 50 to 97%, 60 to Can be 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95%, or 90 to 95%. there is.

The purity of the lactide is at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, such as 40 to 99.9%, 50 to 99.9%, 60 to 99.9%, 70 to 99.9%, 80%. to 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97%, 50 to 97%, 60 to 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95%, or 90 to 95% You can.

In the method for producing acrylic acid and/or glycolide according to the above embodiment, the hydroxyalkanoate copolymer is a glycolide-lactide copolymer,

The step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin includes producing lactide and glycolide by thermally decomposing the glycolide-lactide copolymer in the presence of a catalyst containing tin. May include steps.

Additionally, as described above, before the thermal decomposition, the glycolide-lactide copolymer may be melted.

The glycolide-lactide copolymer is not particularly limited as long as it is a copolymer obtained by polymerizing glycolide monomer and lactide monomer, but for example, it may be a random copolymer obtained by polymerizing glycolide monomer and lactide monomer. Additionally, the glycolide-lactide copolymer may be a block copolymer including one or more polyglycolide blocks and one or more polylactide blocks. That is, the glycolide-lactide copolymer may be a block copolymer obtained by polymerizing polylactide prepolymer and polyglycolide prepolymer. As the glycolide-lactide copolymer contains the above-mentioned blocks, it can exhibit the environmental friendliness and biodegradability of polyglycolide and polylactide.

The polylactide prepolymer may be manufactured by fermentation or polycondensation of lactic acid. The polylactide prepolymer may have a weight average molecular weight of 1,000 g/mol or more, or 5,000 g/mol or more, or 6,000 g/mol or more, or 8,000 g/mol or more, and 50,000 g/mol or less, or 30,000 g/mol or less. In order to increase the crystallinity of the block containing repeating units derived from polylactide prepolymer in the final manufactured block copolymer, the polylactide prepolymer is greater than 20,000 g/mol, or more than 22,000 g/mol, or 23,000 g/mol. It is preferred to have a high weight average molecular weight of at least g/mol, or at least 25,000 g/mol, and at most 50,000 g/mol, or at most 30,000 g/mol, or at most 28,000 g/mol, or at most 26,000 g/mol.

If the weight average molecular weight of the polylactide prepolymer is 20,000 g/mol or less, the polymer crystals are small and it is difficult to maintain the crystallinity of the polymer in the final manufactured block copolymer, and the weight average molecular weight of the polylactide prepolymer is 50,000 g/mol. If it is exceeded, the rate of side reactions occurring inside the prepolymer chain becomes faster than the rate of reaction between polylactide prepolymers during polymerization. Meanwhile, 'lactic acid' used in the present invention refers to L-lactic acid, D-lactic acid, or a mixture thereof.

The polyglycolide prepolymer may be manufactured by fermenting or condensation polymerization of glycolide. The weight average molecular weight of the polyglycolide prepolymer may be 1,000 g/mol or more, or 5,000 g/mol or more, or 8,000 g/mol or more, or 8,500 g/mol or more, and 50,000 g/mol or less, or 30,000 g/mol or less. In the case where it is desired to increase the crystallinity of the repeating unit derived from the polyglycolide prepolymer in the final manufactured block copolymer, the polyglycolide prepolymer must be greater than 20,000 g/mol, or greater than 22,000 g/mol, or greater than 25,000 g/mol. and preferably has a high weight average molecular weight of 50,000 g/mol or less, or 30,000 g/mol or less, or 28,000 g/mol or less.

As explained in the polylactide prepolymer, if the weight average molecular weight of the polyglycolide prepolymer is 20,000 g/mol or less, the crystals of the polymer are small, making it difficult to maintain the crystallinity of the polymer in the final manufactured block copolymer. If the weight average molecular weight exceeds 50,000 g/mol, the side reaction rate that occurs inside the prepolymer chain becomes faster than the reaction rate between polyglycolide prepolymers during polymerization.

That is, at least one of the polylactide prepolymer and the polyglycolide prepolymer may have a weight average molecular weight of more than 20,000 g/mol and less than 50,000 g/mol.

The glycolide-lactide copolymer is a block copolymer in which polylactide prepolymer and polyglycolide prepolymer are polymerized, and the weight ratio of the polylactide prepolymer and polyglycolide prepolymer in the block copolymer is 90:10 to 30: It may be 70, 80:20 to 40:60, or 75:25 to 50:50. If too little of the polyglycolide prepolymer is included in the polylactide prepolymer, brittleness may increase, and if too much of the polyglycolide prepolymer is included in the polylactide prepolymer, the molecular weight is lowered, thereby improving processability and heat resistance. Stability may be reduced.

The glycolide-lactide copolymer has a weight average molecular weight (Mw) measured using gel permeation chromatography (GPC) of 20,000 to 300,000 g/mol, more specifically, 20,000 g/mol or more, 30,000 g/mol or more, 40,000 g/mol or more, 50,000 g/mol or more, 70,000 g/mol or more, or 100,000 g/mol or more, and 300,000 g/mol or less, or 200,000 g/mol or less, or 150,000 g/mol or less It has a weight average molecular weight of . If the weight average molecular weight of the glycolide-lactide copolymer is too small, the overall mechanical properties may be significantly reduced, and if the weight average molecular weight is too large, the process may be difficult and processability and elongation may be low.

In the method for producing lactide and glycolide according to the above embodiment, the glycolide-lactide copolymer is, for example, P2066 (lactide:glycolide = 65:35), P2191 (lactide:glycolide = 65:35) from Sigma-Aldrich. 50:50), P1941 (lactide:glycolide = 75:25), etc., or BD01128150 from BLD pharm.

Additionally, after the glycolide-lactide copolymer is melted, lactide and glycolide can be produced by thermally decomposing the melted glycolide-lactide copolymer. Likewise, the thermal decomposition can also be carried out without solvent.

Meanwhile, in the process of producing lactide and glycolide by thermally decomposing the glycolide-lactide copolymer in the presence of a catalyst containing the tin, the thermal decomposition may be performed at a temperature of 220 ° C. or higher and 350 ° C. or lower, e.g. For example, it may be 220°C or higher, 250°C or higher, 290°C or higher, and may be 350°C or lower, 330°C or lower, and 300°C or lower. If the thermal decomposition temperature is too low, thermal decomposition of the glycolide-lactide copolymer may not be achieved, and if the thermal decomposition temperature is too high, many unexpected impurities may be generated.

The difference between the melting temperature and the thermal decomposition temperature may be 20 ℃ or more and 150 ℃ or less, for example, 20 ℃ or more, 30 ℃ or more, 50 ℃ or more, 60 ℃ or more, 150 ℃ or less, 120 ℃ or less, 100 ℃ or less. , may be below 70°C. If the difference between the melting temperature and the pyrolysis temperature is too small, recovery of the lactide and glycolide may be difficult, and if the difference between the melting temperature and the pyrolysis temperature is too large, many unexpected impurities may be generated.

In addition, the thermal decomposition may be performed at a pressure of more than 1 torr and less than 50 torr, for example, more than 1 torr, more than 2 torr, more than 4 torr, more than 5 torr, less than 50 torr, less than 40 torr, less than 30 torr. , may be 20 torr or less, but is not limited thereto. For example, if the pyrolysis pressure is too low, it may be difficult to recover the produced lactide and glycolide, and if the pyrolysis pressure is too high, a large amount of energy is required, which may reduce economic efficiency.

After the step of producing lactide and glycolide by thermally decomposing the glycolide-lactide copolymer, the lactide and glycolide can be recovered through reduced pressure distillation.

For example, lactide and glycolide prepared by reducing the pressure to a pressure exceeding 1 torr after the thermal decomposition process can be recovered through reduced pressure distillation. Additionally, lactide and glycolide can be recovered through distillation even under normal pressure conditions.

The recovery rates of the lactide and glycolide are respectively 30% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, such as 40 to 99.9%, 50 to 99.9%, 60 to 99.9%. %, 70 to 99.9%, 80 to 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97 %, 50 to 97%, 60 to 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95 %, or 90 to 95%. The recovery rate may be calculated on a weight basis.

The purity of the lactide and glycolide is 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, such as 40 to 99.9%, 50 to 99.9%, 60 to 99.9%, 70 to 90%, respectively. 99.9%, 80 to 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97%, 50 to 97%, 60 to 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95%, or 90 It may be from 95% to 95%.

In the method for producing acrylic acid and/or glycolide according to the above embodiment, the hydroxyalkanoate copolymer is the 3-hydroxypropionate-glycolide copolymer,

In the step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin, the 3-hydroxypropionate-glycolide copolymer is thermally decomposed in the presence of a catalyst containing tin to produce acrylic acid and glycol. It may include the step of manufacturing a ride.

Additionally, as described above, before the thermal decomposition, the 3-hydroxypropionate-glycolide copolymer may be melted. Acrylic acid and glycolide can be produced by thermal decomposition of molten 3-hydroxypropionate-glycolide copolymer. At this time, the thermal decomposition can be performed under solvent-free conditions as described above.

The 3-hydroxypropionate-glycolide copolymer includes a block containing a repeating unit derived from 3-hydroxypropionate and a block containing a repeating unit derived from glycolide, and these blocks are directly bonded or ester bonded. , amide bond, urethane bond, or carbonate bond, it can compensate for the disadvantage of low elongation characteristics of biodegradable resins containing only polyglycolide. Additionally, these copolymers can have excellent biodegradability while complementing the mechanical properties of each homopolymer.

The 3-hydroxypropionate-glycolide copolymer includes a block containing a 3-hydroxypropionate-derived repeating unit represented by the following formula (2), and a glycolide-derived repeating unit represented by the following formula (3) It can contain blocks that contain it.

[Formula 2]

[Formula 3]

The repeating unit derived from 3-hydroxypropionate represented by Formula 2 has the advantage of excellent mechanical properties and a high elongation to break due to a glass transition temperature (Tg) as low as -20°C. Therefore, by chemically combining poly(3-hydroxypropionate) and polyglycolide to produce a block copolymer, a biodegradable material with excellent mechanical properties can be produced.

In addition, the repeating unit represented by Formula 2 and the repeating unit represented by Formula 3 may be linked by a direct bond, ester bond, amide bond, urethane bond, urea bond, or carbonate bond, for example, the hydroxyalkanoate -The glycolide copolymer may be a block copolymer represented by the following formula (1).

[Formula 1]

In Formula 1,

R ₁ and R ₂ are each independently hydrogen, N, O, S, or substituted or unsubstituted C _1-20 alkyl,

X _{1 and}

R' is each independently hydrogen, or C _1-20 alkyl,

L is a direct bond; Substituted or unsubstituted C _1-10 alkylene; Substituted or unsubstituted C _6-60 arylene; or a C _2-60 heteroarylene containing one or more heteroatoms selected from the group consisting of substituted or unsubstituted N, O, and S,

n and m may each independently be an integer from 1 to 10,000.

The n refers to the number of repetitions of the repeating unit derived from 3-hydroxypropionate, and when introduced within the above range, physical properties such as elongation can be adjusted while maintaining the inherent physical properties of polyglycolide. In addition, m refers to the number of repeats of the glycolide-derived repeating unit.

Additionally, X ₁ , X ₂ , and L may be a direct bond.

The above Chemical Formula 1 may be expressed as the following Chemical Formula 1-1.

[Formula 1-1]

In Formula 1-1 above,

n and m may be as described above.

Preferably, n is 10 to 700, m can be 10 to 700, and n is 20 or more, 30 or more, 40 or more, 50 or more, or 60 or more, and is 650 or less, 600 or less, 550 or less, 500 or less. , or may be 450 or less, and m may be 20 or more, 30 or more, 40 or more, 50 or more, or 60 or more, and may be 650 or less, 600 or less, 550 or less, 500 or less, or 450 or less.

The 3-hydroxypropionate-glycolide copolymer may have a weight average molecular weight of 10,000 g/mol or more and 500,000 g/mol or less. For example, the weight average molecular weight of the copolymer is 12,000 g/mol or more, 15,000 g/mol or more, 20,000 g/mol or more, 25,000 g/mol or more, or 30,000 g/mol or more, and 480,000 g/mol or less, It may be less than or equal to 460,000 g/mol, less than or equal to 440,000 g/mol, or less than or equal to 420,000 g/mol.

The 3-hydroxypropionate-glycolide copolymer may be a block copolymer obtained by ring-opening polymerization of a glycolide monomer in the presence of a poly(3-hydroxypropionate) initiator.

For example, the 3-hydroxypropionate-glycolide copolymer may be prepared by preparing poly(3-hydroxypropionate) (step 1); and preparing a block copolymer by ring-opening polymerizing a glycolide monomer in the presence of the poly(3-hydroxypropionate) initiator (step 2).

Step 1 is a step of preparing the poly(3-hydroxypropionate), wherein the poly(3-hydroxypropionate) refers to a homopolymer of 3-hydroxypropionic acid, and the n and Those prepared by adjusting the degree of polymerization taking into account the range of m can be used.

The poly(3-hydroxypropionate) initiator has a weight average molecular weight of 1,000 g/mol or more and 500,000 g/mol or less, 2,000 g/mol or more and 400,000 g/mol or less, 3,000 g/mol or more and 300,000 g/mol or less, It may be 4,000 g/mol or more and 200,000 g/mol or less, 5,000 g/mol or more and 100,000 g/mol or less, and 10,000 g/mol or more and 90,000 g/mol or less.

Step 2 may be a step of ring-opening polymerization of glycolide monomer using poly(3-hydroxypropionate) as an initiator. Step 2 can be carried out as bulk polymerization substantially without using a solvent. At this time, substantially not using a solvent may include the use of a small amount of solvent to dissolve the catalyst, for example, a maximum of less than 1 ml of solvent per kg of monomer used. By proceeding with step 2 as bulk polymerization, it becomes possible to omit the process for removing the solvent after polymerization, and decomposition or loss of the resin in this solvent removal process can also be suppressed.

The weight ratio of the poly(3-hydroxypropionate) initiator and glycolide monomer is 1:99 to 99:1, 5:95 to 90:10, 10:90 to 80:20, and 15:85 to 70:30. , or 20:80 to 50:50.

Meanwhile, since the glycolide ring-opening polymerization reaction is accompanied, it may be carried out in the presence of a glycolide ring-opening catalyst. For example, the ring-opening catalyst may be a catalyst represented by the following formula (4).

[Formula 4]

MA ¹ _p A ² _2-p

In Formula 4 above,

M is Al, Mg, Zn, Ca, Sn, Fe, Y, Sm, Lu, Ti or Zr,

p is an integer from 0 to 2,

A ¹ and A ² may each independently be an alkoxy or carboxyl group.

For example, the catalyst represented by Chemical Formula 4 may be tin(II) 2-ethylhexanoate (Sn(Oct) ₂ ).

Preparation of the 3-hydroxypropionate-glycolide copolymer may be performed at a temperature of 150 to 220 °C for 5 minutes to 10 hours or for 10 minutes to 1 hour.

In the process of producing acrylic acid and glycolide by thermally decomposing the 3-hydroxypropionate-glycolide copolymer in the presence of a catalyst containing the tin, the thermal decomposition may be performed at a temperature of 250 ° C. or higher and 400 ° C. or lower. , for example, may be 250°C or higher, 270°C or higher, 290°C or higher, and may be 400°C or lower, 370°C or lower, and 330°C or lower. If the thermal decomposition temperature is too low, thermal decomposition of the hydroxyalkanoate-glycolide copolymer may not be achieved, and if the thermal decomposition temperature is too high, many unexpected impurities may be generated.

The difference between the melting temperature and the thermal decomposition temperature may be 20 ℃ or more and 150 ℃ or less, for example, 20 ℃ or more, 30 ℃ or more, 50 ℃ or more, 60 ℃ or more, 150 ℃ or less, 120 ℃ or less, 100 ℃ or less. , may be below 70°C. If the difference between the melting temperature and the thermal decomposition temperature is too small, recovery of the acrylic acid and glycolide may be difficult, and if the difference between the melting temperature and the thermal decomposition temperature is too large, many unexpected impurities may be generated.

In addition, the thermal decomposition may be performed at a pressure of more than 1 torr and less than 50 torr, for example, more than 1 torr, more than 2 torr, more than 4 torr, more than 5 torr, less than 50 torr, less than 40 torr, less than 30 torr. , may be 20 torr or less, but is not limited thereto. For example, if the pyrolysis pressure is too low, it may be difficult to recover the produced acrylic acid and glycolide, and if the pyrolysis pressure is too high, a large amount of energy is required, which may reduce economic efficiency.

After the step of producing acrylic acid and glycolide by thermally decomposing the hydroxyalkanoate-glycolide copolymer, the acrylic acid and glycolide can be recovered through reduced pressure distillation.

For example, acrylic acid and glycolide prepared by reducing the pressure to more than 1 torr after the thermal decomposition process can be recovered through reduced pressure distillation. Additionally, acrylic acid and glycolide can be recovered through distillation even under normal pressure conditions.

The recovery rates of the acrylic acid and glycolide are respectively 30% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, such as 40 to 99.9%, 50 to 99.9%, 60 to 99.9%. , 70 to 99.9%, 80 to 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97% , 50 to 97%, 60 to 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95% , or it may be 90 to 95%. The recovery rate may be calculated on a weight basis.

The purity of the acrylic acid and glycolide is 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, such as 40 to 99.9%, 50 to 99.9%, 60 to 99.9%, 70 to 99.9%, respectively. %, 80 to 99.9%, 90 to 99.9%, 40 to 99%, 50 to 99%, 60 to 99%, 70 to 99%, 80 to 99%, 90 to 99%, 40 to 97%, 50 to 97 %, 60 to 97%, 70 to 97%, 80 to 97%, 90 to 97%, 40 to 95%, 50 to 95%, 60 to 95%, 70 to 95%, 80 to 95%, or 90 to It could be 95%.

According to the present invention, there is an environmentally friendly and economical method for producing acrylic acid and/or glycolide by thermally decomposing hydroxyalkanoate copolymers and converting them into recyclable acrylic acid and/or glycolide in high purity and high yield. can be provided.

The invention is explained in more detail in the following examples. However, the following examples only illustrate the present invention, and the content of the present invention is not limited by the following examples.

Preparation Example 1: Preparation of 3-hydroxypropionate-lactide block copolymer

(1) Production of polylactic acid prepolymer

25 g of 85% L-lactic acid aqueous solution was added to a 100 ml Schlenk flask in an oil bath and the pressure was reduced for 2 hours at 70°C and 50 mbar to remove moisture in L-lactic acid. Afterwards, based on 100 parts by weight of lactate, 0.4 parts by weight of p-toluenesulfonic acid (p-TSA) and 0.1 parts by weight of SnCl ₂ catalyst were respectively added, and a melt condensation polymerization reaction was performed at a temperature of 150° C. for 12 hours. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain a polylactic acid prepolymer (weight average molecular weight: 8,000 g/mol).

(2) Poly(3-hydroxypropionate) prepolymer production

Add 25 ml of 60% 3-hydroxypropionate aqueous solution to a 100 ml Schlenk flask in an oil bath, remove moisture in the 3-hydroxypropionate for 3 hours at 50 ℃ and 50 mbar, and then incubate at 70 ℃ and After oligomerization at 20 mbar for 2 hours, 0.4 parts by weight of p-toluenesulfonic acid (p-TSA) catalyst based on 100 parts by weight of 3-hydroxypropionate was added to the reaction flask, and incubated at a temperature of 110°C for 24 hours. A melt condensation reaction was performed. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain poly(3-hydroxypropionate) prepolymer (weight average molecular weight: 26,000 g/mol).

(3) Preparation of block copolymers

The polylactic acid prepolymer and the poly(3-hydroxypropionate) prepolymer were mixed in a 100 ml Schlenk flask in an oil bath at a weight ratio of 9:1, added to a total content of 30 g, and p-toluenesulfonic acid ( 90 mg of p-TSA) was added, and annealing was performed at 60°C for 3 hours. Afterwards, 3-hydroxypropionate-lactide block copolymer (weight average molecular weight: 130,000 g/mol) was prepared by solid-phase polymerization reaction using an evaporator and mixing at 150°C and 0.5 mbar for 24 hours.

Meanwhile, the weight average molecular weight of the polylactic acid prepolymer, poly(3-hydroxypropionate) prepolymer, and block copolymer was measured using gel permeation chromatography (GPC).

Preparation Example 2: Preparation of hydroxyalkanoate-glycolide copolymer

(1) Production of poly(3-hydroxypropionate)

Add 25 ml of 60% 3-hydroxypropionate aqueous solution to a 100 ml Schlenk flask in an oil bath, remove moisture in the 3-hydroxypropionate for 3 hours at 50 ℃ and 50 mbar, and then incubate at 70 ℃ and After oligomerization at 20 mbar for 2 hours, 0.4 parts by weight of p-toluenesulfonic acid (p-TSA) catalyst based on 100 parts by weight of 3-hydroxypropionate was added to the reaction flask, and incubated at a temperature of 110°C for 24 hours. A melt condensation reaction was performed. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain poly(3-hydroxypropionate) (weight average molecular weight: 26,000 g/mol).

(2) Block copolymer manufacturing

Add 20 g of glycolide, 5 g of poly(3-hydroxypropionate), and 20 mg of tin(II) 2-ethylhexanoate to a 500 mL Teflon-coated round flask and vacuum sufficiently. It was hung and vacuum dried at room temperature for 4 hours. Afterwards, the flask was placed in an oil bath pre-heated at 130°C, the temperature was raised to 220°C, and a ring-opening polymerization reaction was performed for 30 minutes. After the reaction was completed, the remaining monomers were removed through a devolatilization step of the product to obtain the final block copolymer (weight average molecular weight: 130,000 g/mol).

Meanwhile, the weight average molecular weight of the poly(3-hydroxypropionate) and block copolymer was measured using gel permeation chromatography (GPC).

<Examples and Comparative Examples>

Example 1

15 g of the 3-hydroxypropionate-lactide block copolymer prepared in Preparation Example 1 was added to the flask and dissolved by heating to 180°C. After confirming dissolution, 0.03 ml of tin 2-ethylhexanoate was added. Afterwards, the reaction temperature was raised to 220°C and stirred for 1 hour. Afterwards, 2.9 g of pyrophosphoric acid and 18 g of tetrabutylphosphonium bromide were added, stirred at 220°C for 1 hour, and then the temperature was raised to 290°C to recover distilled acrylic acid. After completion of the reaction, a total of 9 g of acrylic acid was recovered.

Example 2

15 g of the 3-hydroxypropionate-lactide block copolymer prepared in Preparation Example 1 was added to the flask and dissolved by heating to 180°C. After confirming dissolution, 0.03 ml of tin 2-ethylhexanoate was added. Afterwards, the reaction temperature was raised to 220°C, the reactor was reduced to 5 torr, the first thermal decomposition reaction was performed, and the lactide distilled out was recovered. Afterwards, the internal temperature of the reactor was raised to 290°C and stirred to proceed with a secondary thermal decomposition reaction, and acrylic acid and lactide distilled out were recovered. After completion of the reaction, a total of 9 g of lactide and 2 g of acrylic acid were recovered, respectively.

Example 3

15 g of the 3-hydroxypropionate-lactide block copolymer prepared in Preparation Example 1 was added to the flask and dissolved by heating to 180°C. After confirming dissolution, 0.03 ml of tin 2-ethylhexanoate was added. Thereafter, the reaction temperature was raised to 220°C and stirred at that temperature for 1 hour. After stirring, the pressure inside the reactor was reduced to 5 torr to recover lactide. Thereafter, the internal temperature of the reactor was raised to 290° C. to proceed with a secondary thermal decomposition reaction, and the distilled acrylic acid and lactide were recovered. After completion of the reaction, a total of 10 g of lactide and 2 g of acrylic acid were each recovered.

Example 4

15 g of glycolide-lactide copolymer (P1941, Sigma-aldrich, Lactide: glycolide = 75:25) was added to the flask and heated to 220°C to melt. After confirming melting, 0.03 ml of tin 2-ethylhexanoate was added. Afterwards, the reaction temperature was raised to 290°C, the reactor was reduced to 5 torr, and 3.0 g of glycolide (recovery: 79%) and 10.2 g of lactide (recovery: 91%) were recovered by distillation.

Example 5

15 g of glycolide-lactide copolymer (P2191, Sigma-aldrich, Lactide: glycolide = 50:50) was added to the flask and heated to 220°C to melt. After confirming melting, 0.03 ml of tin 2-ethylhexanoate was added. Afterwards, the reaction temperature was raised to 290°C, and the reactor was reduced to 5 torr to recover 6.2 g of distilled glycolide (recovery: 83%) and 6.5 g of lactide (recovery: 87%).

Example 6

15 g of the hydroxyalkanoate-glycolide copolymer prepared in Preparation Example 2 was added to the flask and melted by heating to 220°C. After confirming melting, 0.03 ml of tin 2-ethylhexanoate was added. Afterwards, the reaction temperature was raised to 290°C, the reactor was reduced to 5 torr, and the distilled glycolide and acrylic acid were recovered.

Comparative Example 1

10 g of lactide was added to a 100 ml 3-neck RB flask, and 2.9 g of solid pyrophosphoric acid and 18 g of tetrabutylphosphonium bromide were added at room temperature. Afterwards, the internal temperature was raised to 220°C, the reaction was performed, and acrylic acid distilled out after completion of the reaction was recovered.

Comparative Example 2

Add 20 g of polylactic acid pellets and dissolve by heating to 220°C. Then, add 0.03 ml of tin 2-octylate. At the same temperature, 16.3 g of distilled lactide (recovery rate: 81.5%) was recovered by reducing the pressure to 5 torr.

Comparative Example 3

5.0 g of poly(3-hydroxypropionic acid), 50 mg of pentamethyl diethylene triamine, and 10 mg of hydroquinone mono ethyl ether (MEHQ) were added to the flask and mixed by stirring. The reaction temperature was raised to 80°C and stirred for 2 hours. At this time, melting of poly(3-hydroxypropionic acid) was not observed. Afterwards, the temperature inside the reaction was heated to 290°C, and the acrylic acid distilled out was recovered. After completion of the reaction, a total of 3.8 g of acrylic acid was recovered (recovery rate: 76%).

evaluation

1. Recovery rate evaluation

The recovery rates (mol yield) of acrylic acid, lactide, and glycolide prepared in Examples and Comparative Examples were calculated, and the results are shown in Table 1 below. If it was not recovered, it was marked with ‘-’.

2. Purity evaluation

The purity of acrylic acid, lactic acid, and glycolide prepared in Examples and Comparative Examples was measured using ¹ H NMR (400 MHz, CDCl ₃ ), and the results are shown in Table 1 below.

Example
One Example
2 Example
3 Example
4 Example
5 Example
6 Comparative example
One Comparative example
2 Comparative example
3 Acrylic acid recovery rate (%) 69 67 67 - - 65 47 - 76 Acrylic acid purity (%) 99 99 99 - - 99 99 - 87 Acrylic acid and lactide recovery rates
(Acrylic acid:lactide weight ratio) - 73% (9:2) 80% (10:2) - - - - - - Lactide recovery rate (%) - - - 91 87 - - 82 - Lactide purity (%) - - - > 98 > 98 - - > 98 - Glycolide recovery rate (%) - - - 79 83 72 - - - Glycolide purity (%) - - - > 98 > 98 99 - - -

According to Table 1, it was confirmed that Example 1 had a high recovery rate and purity of acrylic acid, and that Examples 2 and 3 could recover lactide and acrylic acid with high purity and high yield, respectively. In addition, it was confirmed that Examples 4 and 5 recovered lactide with a recovery rate of 87% or more and glycolide with a recovery rate of 79% or more, and the purities of each exceeded 98%. Additionally, Example 6 confirmed that acrylic acid and glycolide were recovered with high purity and high yield, respectively.

Meanwhile, it was confirmed that Comparative Example 1 had a significantly low recovery rate of acrylic acid, and Comparative Example 2 only recovered lactide due to thermal decomposition of polylactic acid, but acrylic acid and/or glycolide could not be recovered. Additionally, in Comparative Example 3, it was confirmed that the polymer was not melted even though the polymer was heated at 80°C for 2 hours. When the polymer was thermally decomposed at 290°C, the pentamethyl diethylene triamine catalyst was also vaporized to produce acrylic acid and It was confirmed that the purity of acrylic acid was significantly reduced due to mixing.

Claims (19)

A method for producing acrylic acid and/or glycolide, comprising: thermally decomposing a hydroxyalkanoate copolymer in the presence of a catalyst containing tin.
According to paragraph 1,
Before the step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin,
A method for producing acrylic acid and/or glycolide, further comprising the step of melting the hydroxyalkanoate copolymer.
According to paragraph 2,
A method for producing acrylic acid and/or glycolide, wherein the melting is carried out solvent free.
According to paragraph 2,
A method for producing acrylic acid and/or glycolide, wherein the melting is performed at a temperature of 150°C or more and 250°C or less.
According to paragraph 1,
A method for producing acrylic acid and/or glycolide, wherein the thermal decomposition is carried out without a solvent.
According to paragraph 1,
The hydroxyalkanoate copolymer is acrylic acid, comprising two or more repeating units selected from the group consisting of repeating units derived from 3-hydroxypropionic acid, repeating units derived from lactic acid or lactide, and repeating units derived from glycolic acid or glycolide. and/or a process for producing glycolide.
According to paragraph 1,
The hydroxyalkanoate copolymer is 3-hydroxypropionate-lactide copolymer, glycolide-lactide copolymer, or 3-hydroxypropionate-glycolide copolymer. Acrylic acid and/or glycolide production method.
In clause 7,
The step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin,
A method for producing acrylic acid and/or glycolide, comprising: producing acrylic acid by thermally decomposing the 3-hydroxypropionate-lactide copolymer in the presence of a catalyst containing the tin.
According to clause 8,
A method for producing acrylic acid and/or glycolide, wherein the thermal decomposition is performed at a temperature of 200 ℃ or more and 350 ℃ or less.
According to clause 8,
A method for producing acrylic acid and/or glycolide, in which an acid and a phosphonium salt are added after the addition of a catalyst containing the tin.
In clause 7,
The step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin,
Preparing lactide by first thermally decomposing the 3-hydroxypropionate-lactide copolymer in the presence of a catalyst containing the tin; and
A method for producing acrylic acid and/or glycolide, comprising: producing acrylic acid by secondary thermal decomposition of the first thermally decomposed hydroxyalkanoate-lactide copolymer.
According to clause 11,
A method for producing acrylic acid and/or glycolide, wherein the first thermal decomposition is performed at a temperature of 200 ℃ or more and 250 ℃ or less.
According to clause 11,
A method for producing acrylic acid and/or glycolide, wherein the secondary thermal decomposition is performed at a temperature of 250 ℃ or more and 300 ℃ or less.
According to clause 11,
A method for producing acrylic acid and/or glycolide, wherein the difference between the first pyrolysis temperature and the second pyrolysis temperature is 20 ℃ or more and 100 ℃ or less.
In clause 7,
The step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin,
A method for producing acrylic acid and/or glycolide, comprising: producing lactide and glycolide by thermally decomposing the glycolide-lactide copolymer in the presence of a catalyst containing the tin.
According to clause 15,
A method for producing acrylic acid and/or glycolide, wherein the thermal decomposition is performed at a temperature of 220 ℃ or more and 350 ℃ or less.
In clause 7,
The step of thermally decomposing the hydroxyalkanoate copolymer in the presence of a catalyst containing tin,
A method for producing acrylic acid and/or glycolide, comprising: producing acrylic acid and glycolide by thermally decomposing the 3-hydroxypropionate-glycolide copolymer in the presence of a catalyst containing the tin.
According to clause 17,
A method for producing acrylic acid and/or glycolide, wherein the thermal decomposition is performed at a temperature of 250 ℃ or more and 400 ℃ or less.
According to paragraph 1,
The method for producing acrylic acid and/or glycolide is to recycle biodegradable articles containing the hydroxyalkanoate copolymer.