JP2002167430A - Aliphatic polyester, method for producing the same, and method for making starch as resource - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novel aliphatic polyester from a starch as a starting material, a method for producing the polyester, and a method for making the starch as a resource. SOLUTION: The polyester represented by formula (I) [wherein R is hydrogen atom, an acetyl group or a 1-3C linear or branched alkyl group; (n) is an integer of 10-6,000] is produced by the step for obtaining D-glucose by the hydrolysis of the starch, the step for obtaining gluconolactone represented by formula (II) from D-glucose [wherein R is hydrogen atom, acetyl group or a 1-3C linear or branched alkyl group] and the step for the ring opening polymerization of gluconolactone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an aliphatic polyester, a method for producing an aliphatic polyester, and a method for recycling starch.

[0002]

2. Description of the Related Art Conventional general-purpose plastic products are polymer compounds synthesized from petroleum resources. That is, polymer compounds such as polyester, polystyrene, nylon, polyethylene, polyvinyl chloride, polyimide, and polycarbonate are all synthesized from petroleum. However, petroleum is a finite resource and is expected to eventually run out. Therefore, there is a strong demand for a technology for producing a general-purpose plastic product from a new raw material instead of petroleum, that is, a renewable raw material.

[0003] On the other hand, starch is a polymer compound obtained by dehydrative polymerization of D-glucose, and is an important polysaccharide together with cellulose. Starch is produced from potatoes, sweet potatoes, corn, etc., and its global production (corn yield) is about 400-500 million tons / year, which is the most produced and renewable resource among natural resources. is there. If general-purpose plastic products can be manufactured from starch, it is very promising as a new alternative to petroleum.

[0004]

An object of the present invention is to provide a novel aliphatic polyester obtained from starch as a raw material, a method for producing the same, and a method for recycling starch.

[0005]

SUMMARY OF THE INVENTION The present inventor has conducted intensive research and development in view of the recognition that new technology development is required in preparation for the future depletion of petroleum resources. Focusing on starch as, for the first time found that it is possible to synthesize an aliphatic polyester having a relatively large molecular weight from gluconolactone or a derivative thereof obtained from starch via D-glucose, and therefore capable of replacing conventional plastic products, The present invention has been made. And this opens the way to the efficient use of starch as a starting material to obtain high-quality plastics.

The aliphatic polyester which can achieve the above object is represented by the following general formula (1)

[0007]

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(Wherein R represents a hydrogen atom, an acetyl group, or a linear or branched alkyl group having 1 to 3 carbon atoms), and is characterized by having a structural unit represented by the formula: The degree of polymerization n is an integer of 3 to 20,000.

The method for producing the aliphatic polyester of the present invention, which can achieve the above object, is represented by the following general formula (I):

[0010]

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(Wherein R represents a hydrogen atom, an acetyl group, or a linear or branched alkyl group having 1 to 3 carbon atoms, and n represents an integer of 3 to 20,000). A method for producing an aromatic polyester, comprising the following general formula (II)

[0012]

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(Wherein R represents a hydrogen atom, an acetyl group, or a linear or branched alkyl group having 1 to 3 carbon atoms), and a step of ring-opening polymerizing gluconolactone represented by the formula: It is characterized by the following.

The method for producing an aliphatic polyester of the present invention comprises, among others, a step of (I) hydrolyzing starch to obtain D-glucose in that starch is used as a raw material instead of petroleum resources; The above-mentioned general formula (I)
Obtaining a gluconolactone represented by I), and
(iii) The gluconolactone preferably has a step of ring-opening polymerization.

Furthermore, the method for recycling starch of the present invention, which can achieve the above object, comprises: (i) a step of hydrolyzing starch to obtain D-glucose; Formula (II)

[0016]

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(Wherein R represents a hydrogen atom, an acetyl group, or a linear or branched alkyl group having 1 to 3 carbon atoms), a step of obtaining a gluconolactone represented by the following formula:
And (iii) ring-opening polymerization of the gluconolactone to obtain the following general formula (I)

[0018]

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Wherein R represents a hydrogen atom, an acetyl group, or a linear or branched alkyl group having 1 to 3 carbon atoms, and n represents an integer of 3 to 20,000. And a step of obtaining an aromatic polyester.

Lactone is a compound having an intramolecular cyclic ester structure, and some of them give an aliphatic polyester by ring-opening polymerization. Such aliphatic polyesters are used in many industrial fields as plastic molded articles, films, hot melt adhesives and the like. As a lactone used as a raw material of the aliphatic polyester, for example, ε-caprolactone (Japanese Patent Laid-Open No.
JP-A-158172), δ-valerolactone, butyrolactone, etc. are known, but examples of obtaining an aliphatic polyester by ring-opening polymerization of gluconolactone represented by the above general formula (II) other than the present inventors Has not been found yet, and the aliphatic polyester represented by the general formula (I) of the present invention is a novel polymer compound.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The aliphatic polyester of the present invention comprises
It has a structure represented by the following general formula (I). And
The aliphatic polyester represented by the general formula (I)
It can be manufactured from starch.

[0022]

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(In the formula, R represents a hydrogen atom, an acetyl group, or a linear or branched alkyl group having 1 to 3 carbon atoms. N represents an integer of 3 to 20,000.) In I), R is a hydrogen atom, an acetyl group or an alkyl group having 1 to 3 carbon atoms. The alkyl group may be linear or branched. Further, the alkyl group may have a substituent. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, and an i-propyl group. R is preferably a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.

N represents the degree of polymerization and is an integer of 3 to 20,000.

The aliphatic polyester represented by the general formula (I) of the present invention can be obtained, for example, by ring-opening polymerization of gluconolactone represented by the following general formula (II).

[0026]

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(In the formula, R represents a hydrogen atom, an acetyl group, or a linear or branched alkyl group having 1 to 3 carbon atoms.) In the above general formula (II), R represents a hydrogen atom, acetyl Or an alkyl group having 1 to 3 carbon atoms. The alkyl group may be linear or branched. Further, the alkyl group may have a substituent. The aliphatic polyester represented by the general formula (I) is obtained by ring-opening polymerization of gluconolactone represented by the general formula (II),
R in I) corresponds to R in general formula (I).

The gluconolactone represented by the general formula (II) can be obtained from starch via D-glucose. Therefore, by establishing a method for synthesizing an aliphatic polyester using gluconolactone as a raw material, it becomes possible to synthesize an aliphatic polyester from starch, and a new route to starch recycling can be opened.

That is, the aliphatic polyester of the present invention comprises (i) a step of hydrolyzing starch to obtain D-glucose, and (ii) converting gluconolactone represented by the above general formula (II) from the D-glucose. It is preferable that the gluconolactone is produced through the following steps: (iii) ring-opening polymerization of the gluconolactone to obtain the aliphatic polyester represented by the general formula (I). This method for producing an aliphatic polyester is also a useful method for recycling starch.

The steps (i) to (iii) will be described below. Step (i) (starch → D-glucose) The conversion of starch into D-glucose is performed, for example, by a hydrolysis method using a dilute acid such as sulfuric acid, a hydrolysis method using an enzyme such as amylase / maltase, or using supercritical water. Examples include a hydrolysis method. The reaction conditions may be appropriately determined according to a known method. Step (ii) (D-glucose → gluconolactone) The following gluconolactone (II) -a can be obtained by brominating D-glucose (HSIsbell).
et.al., J. Res. Nat. Bur. Stand., 10 , pp. 337-356,193
3). Gluconolactone (II) -a is a compound of the above general formula (II) wherein R = H (D-Gluconic acid, δ-lacton)
e).

[0031]

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The following gluconolactone (II) -b can be obtained by acetylating gluconolactone (II) -a with zinc chloride and acetic anhydride (CLNelson, Carbohydrate).
hydr. Res., 106 , pp. 155-159, 1982). Gluconolactone
(II) -b is a compound wherein R = CH ₃ CO (D-Gluconic acid,
δ-lactone, 2,3,4,6-tetraacetate).

[0033]

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The following gluconolactone (II) -c is obtained by methylating D-glucose with dimethyl sulfate and sodium hydroxide, and then hydrolyzing the methyl glucoside with dilute hydrochloric acid to give 2,3,4,6-tetrafluoroethylene. -O-methyl-D-glucose (ESWest et al., Organic Syntheses Collect. Vo.
l. III, Wiley, New York, NY, pp. 800-803, 1955), which can be obtained by oxidation with pyridinium chlorochromate (R. Bihovsky et al., J. Org. Chem., 53) . , pp.4026-40
31,1988). Gluconolactone (II) -c has R = CH ₃ (D-Gluconic acid, 2,3,4,6-tetra-O-methyl, δ-
lactone).

[0035]

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The following gluconolactone (II) -d is converted from D-glucose through methyl-D-glucose into 1-methyl-2,3,4,6-tetra-O-ethyl-D-glucose (JSBrimacombe et al., Carbohydr. Res., 2 , p
167-169, 1966), which can be obtained by oxidation with tin tetrachloride and trimethylsilyl azide in methylene chloride (M. Goebel et al., Tetrahedron, 53 (9) , pp. 3123 ) .
~ 3134,1997). Gluconolactone (II) -d has the formula: R ＝ CH ₃
CH ₂ (D-Gluconic acid, 2,3,4,6-tetra-Oe
thyl, δ-lactone).

[0037]

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Other gluconolactones can be obtained in a similar manner. The reaction conditions for producing gluconolactone from D-glucose may be appropriately determined according to a known method or in accordance therewith. Step (iii) (gluconolactone → aliphatic polyester; ring-opening polymerization) In the present invention, an aliphatic polyester is generally synthesized by ring-opening polymerization of gluconolactone using a compound having a hydroxyl group as an initiator in the presence of a catalyst. I do. The initiator is used to open the gluconolactone, and the catalyst interacts with the ring-opened product and the polymerization proceeds. (Polymerization catalyst) In the present invention, the following metal compounds can be used as a polymerization catalyst in the ring-opening polymerization of gluconolactone. Specifically, monobutyltin oxide, dibutyltin oxide, tetra (acetate) tin, tri (acetate) butyltin, di (acetate) dibutyltin, acetate tributyltin, tri (acetate) phenyltin, di (methoxy) dibutyltin, methoxytributyltin, tri ( 2-ethylhexanoate) butyltin, di (2-ethylhexanoate) dibutyltin, di (laurate) dibutyltin, di (octanoate) tin, di (2,4-pentanedionate) tin, tin dichloride, tetrachloride Tin compounds such as tin, aluminum compounds such as tri (isopropoxy) aluminum, di (isopropoxy) ethylaluminum, isopropoxydiethylaluminum, aluminum chloride, di (butoxy) zinc, di (2,2- Methyl-3,
Zinc compounds such as 5-heptanedionate) zinc and zinc chloride, titanium compounds of tetra (butoxy) titanium, zirconium compounds of tetra (butoxy) zirconium, La, Nd, Sm, Er, Tm, Yb, Lu, etc. Organic rare earth compounds and the like can be used. These may be used alone or
More than one type may be used in combination.

The use amount of the polymerization catalyst of the present invention may be determined as appropriate, but is usually 0.01 to 10% by weight, preferably 0.05% by weight or more and 5% by weight or less based on the total amount of gluconolactone and the polymerization initiator. It is. (Polymerization Initiator) In the present invention, the following alcohols can be used as the polymerization initiator in the ring-opening polymerization of gluconolactone. Specifically, methanol, ethanol,
1-propanol, 2-propanol, various butanols, monools such as phenol, ethylene glycol,
1,3-propanediol, 1,4-butanediol,
Diethylene glycol, 1,5-pentanediol,
Diols such as 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol and 1,10-decanediol, diols such as glycerin and trimethylolpropane, polyols such as neopentyl glycol and pentaerythritol are used. Can be used. These may be used alone or in combination of two or more.

The molar ratio between the polymerization initiator and gluconolactone used in the present invention can be appropriately selected according to the desired polymerization ratio of the aliphatic polyester. The molar ratio of the polymerization initiator to gluconolactone is usually from 1: 1 to 1: 500.
0, preferably 1: 1 to 1: 2000.

In the ring-opening polymerization of gluconolactone, a polymerization catalyst and a polymerization initiator are added to gluconolactone to carry out a polymerization reaction in the presence of an inert gas or under reduced pressure. The ring-opening polymerization of gluconolactone is preferably performed under a nitrogen atmosphere at normal pressure for convenience.

The reaction temperature and time for the ring-opening polymerization of gluconolactone can be arbitrarily selected. The reaction temperature is preferably 50 ° C. or higher, more preferably 100 ° C. or higher, since a sufficiently high reaction rate can be obtained. Particularly, the temperature is preferably 180 ° C. or lower. The reaction time can be arbitrarily selected, and the reaction can be performed within a range that does not affect the quality of the aliphatic polyester to be produced.

The ring-opening polymerization of gluconolactone can be carried out in a solvent. The solvent is gluconolactone, a polymerization catalyst, an inert solvent which does not react with the polymerization initiator, and it is preferable to use an aromatic or alicyclic hydrocarbon such as toluene, an aromatic hydrocarbon such as xylene, or hexane or cyclohexane. . These solvents are preferably substantially anhydrous. The reaction temperature is generally from 0 ° C to the boiling point of the solvent or lower, preferably from 0 to 30 ° C.

With regard to the molecular weight of the aliphatic polyester obtained by ring-opening polymerization of gluconolactone, gluconolactone having a hydroxyl group substituted tends to give a higher molecular weight under the same reaction conditions. Specifically, the weight average molecular weight of the aliphatic polyester is 3 in terms of polystyrene.
It is preferably at least 000, particularly preferably at least 10,000, more preferably at most 2,000,000, particularly preferably at most 14,000,000 in terms of polystyrene.

The aliphatic polyester according to the present invention thus obtained can be used as a substitute for a plastic material used in various fields. Then, by changing the weight average molecular weight, the contained functional group, and the like, it can be applied to many industrial fields. For example, an aliphatic polyester having a weight-average molecular weight of 500 to 5000 using glycol as a polymerization initiator is very useful as a raw material for polyurethane or a raw material for paints, taking advantage of having a hydroxyl group. Further, the aliphatic polyester having a weight average molecular weight of more than 50,000 has practical mechanical strength and can be used for plastic molded articles, films, hot melt adhesives and the like. Examples of the molding method include a compression molding method, an injection molding method, an extrusion molding method, a casting method, and transfer using a mold.

Further, the aliphatic polyester of the present invention includes:
Within the range not impairing the object of the present invention, other resin components, rubber components, heat stabilizers, weather stabilizers, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, nucleating agents, dyes, pigments, Natural oil, synthetic oil, wax and the like can be blended. The mixing ratio is not particularly limited, and may be appropriately determined.

[0047]

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. (Example 1) 500 parts by weight of starch (manufactured by Wako Pure Chemical Industries) was added to 4500 parts by weight of water and dissolved while heating. 5000 parts by weight of 3 mol / l sulfuric acid was added thereto, and 8
The mixture was reacted by stirring at 0 ° C. for 5 hours. After the reaction was completed, anhydrous sodium carbonate was added to neutralize the aqueous solution, and then an ion exchange resin column (Amberlite IR-120, manufactured by Organo Corporation) was used.
After passing through B), the solvent was distilled off. Then, the reaction mixture was separated and purified to obtain 300 parts by weight of D-glucose.

Using FT-NMR DPX400 manufactured by Bruker, ¹³ C-NMR of synthesized D-glucose (100 MHz, internal standard DMSO-d
₆ ) was measured. The chemical shift δ (ppm) was as follows. D-glucose: ¹³ C-NMR (100 MHz, DMSO-d ₆ ) δ /
ppm α-form: 92.12, 73.04, 72.29, 71.80,
70.58, 61.20 β type: 96.79, 76.70, 76.59, 74.78,
70.30, 61.00 After saturating carbon dioxide to 8000 parts by weight of a 12% aqueous barium carbonate solution, 330 parts by weight of bromine and 300 parts by weight of D-glucose are added thereto, and the mixture is stirred at 25 ° C. for 30 minutes to obtain the following. Gluconolactone 250 represented by the chemical formula (II) -a
Parts by weight were obtained.

[0049]

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¹³ C—N of synthesized gluconolactone (II) -a
MR (100 MHz, internal standard DMSO-d ₆ ) was measured. The chemical shift δ (ppm) was as follows. Gluconolactone (II) -a: ¹³ C-NMR (100 MHz, DMSO-
d ₆ ) δ / ppm 171.88, 81.23, 73.79, 71.43, ₆
7.82, 60.14 100 parts by weight of gluconolactone (II) -a were added under nitrogen atmosphere.
The mixture was heated to 160 ° C., and 0.2 parts by weight of monobutyltin oxide as a polymerization catalyst and 0.5 parts by weight of diethylene glycol as a polymerization initiator were added thereto to synthesize an aliphatic polyester. The polymerization time was 4 hours.

The weight average molecular weight of the obtained aliphatic polyester was 450,000 in terms of polystyrene, and the average degree of polymerization was 25.
30.

For the synthesized aliphatic polyester, BI
IR was measured by the KBr tablet method using FT-IR FTS135 manufactured by ORAD. FIG. 1 shows the measurement results of IR. The wave number ν (cm ⁻¹ ) of the absorption band was as follows. Aliphatic polyester: ν / cm ⁻¹ 3460, 1750, 1230, 1040, 1140
1080 The ¹³ C-NMR (100 MHz, internal standard DMSO-d ₆ ) of the synthesized aliphatic polyester was measured. The chemical shift δ (ppm) was as follows. Aliphatic polyester: ¹³ C-NMR (100 MHz, DMSO-d ₆ )
δ / ppm 175.54, 81.27, 73.13, 72.62, 6
9.27, 62.68 From the above measurement results, it was confirmed that the desired aliphatic polyester was synthesized. (Example 2) 250 parts by weight of gluconolactone (II) -a obtained from starch in the same manner as in Example 1 was treated with zinc chloride (12
5 parts by weight) and a solution of acetic anhydride (1250 parts by weight), and reacted by stirring at room temperature for 40 minutes. Then, the reaction solution was poured into ice water and extracted with chloroform. After removing chloroform of the solvent, it is separated and purified by the following chemical formula (II)
460 parts by weight of gluconolactone represented by -b were obtained.

[0053]

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¹ H-NM of synthesized gluconolactone (II) -b
R (400 MHz, internal standard CDCl ₃ ) was measured. The chemical shift δ (ppm) was as follows. Gluconolactone (II) -b: ¹ H-NMR (400 MHz, CDC
l ₃ ) δ / ppm 2.07 (s, 3H), 2.09 (s, 3H), 2.10 (s,
3H), 2.15 (s, 3H), 4.26 (dd, 1H), 4.4
0 (dd, 1H), 4.65 to 4.68 (m, 1H), 5.22
(d, 1H), 5.41 (t, 1H), 5.57 (t, 1H) 100 parts by weight of gluconolactone (II) -b was heated to 160 ° C. under a nitrogen atmosphere, and triazine was added thereto as a polymerization catalyst. Aliphatic polyester was synthesized by adding 0.3 parts by weight of (isopropoxy) aluminum and 0.6 parts by weight of 1,4-butanediol as a polymerization initiator. The polymerization time was 4 hours.

The weight average molecular weight of the aliphatic polyester obtained was 13.37 million in terms of polystyrene, and the average degree of polymerization was 3
960.

The IR of the synthesized aliphatic polyester was measured. FIG. 2 shows the measurement results of IR. The wave number ν (cm ⁻¹ ) of the absorption band was as follows. Aliphatic polyester: ν / cm ⁻¹ 1760, 1430, 1380, 1230, 1040 ¹³ C-NMR (100 MHz, internal standard CDCl ₃ ) of the synthesized aliphatic polyester was measured. The chemical shift δ (ppm) was as follows. Aliphatic polyester: ¹³ C-NMR (100 MHz, CDCl ₃ ) δ
/ Ppm 171.51, 170.47, 169.97, 169.4
1, 169.14, 78.86, 74.22, 71.00,
67.63, 62.13, 20.51, 20.47, 20.
26, 20.21 From the above measurement results, it was confirmed that the desired aliphatic polyester was synthesized. (Example 3) D obtained from starch in the same manner as in Example 1
Adding 300 parts by weight of glucose to 180 parts by weight of water,
Stirred at 5 ° C. To this, 3840 parts by weight of a carbon tetrachloride solution containing 1440 parts by weight of dimethyl sulfuric acid were added.
6960 parts by weight of a 10% aqueous sodium hydroxide solution were added. Thereafter, the reaction temperature was adjusted to 70 to 75 ° C., and 2,500 parts by weight of dimethyl sulfuric acid was added to the mixture, and the mixture was stirred and reacted for 30 minutes. Then, the reaction mixture was diluted with sufficient water and extracted with chloroform. After removing the solvent chloroform, 2
5000 parts by weight of N hydrochloric acid were added, and the mixture was heated and stirred for 1 hour. This was extracted with chloroform, and the solvent was removed to obtain a syrup-like product. This was washed with ether, crystallized, and further washed with ether to obtain 220 parts by weight of 2,3,4,6-tetra-O-methyl-D-glucose.

¹³ C-NMR (100 MHz, internal standard CD) of the synthesized 2,3,4,6-tetra-O-methyl-D-glucose
Cl ₃ ) was measured. The chemical shift δ (ppm) was as follows. 2,3,4,6-tetra-O-methyl-D-glucose: ¹³ C-NM
R (100 MHz, CDCl ₃ ) δ / ppm α form: 58.87, 59.19, 60.45, 60.89,
69.95, 71.30, 79.50, 81.95, 83.
12, 90.73 β type: 58.87, 59.23, 60.52, 60.81,
71.58, 74.39, 79.62, 84.82, 86.
38,97.14 To 2050 parts by weight of a dichloromethane solution containing 396 parts by weight of pyridinium chlorochromate, 1870 parts by weight of a dichloromethane solution containing 220 parts by weight of 2,3,4,6-tetra-O-methyl-D-glucose were added. Reflux for 8 hours. Then, the reaction mixture was diluted with ether and filtered with magnesium silicate. After removing the solvent, the residue was distilled under reduced pressure to obtain 190 parts by weight of gluconolactone represented by the following chemical formula (II) -c.

[0058]

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¹ H-NM of synthesized gluconolactone (II) -c
R (400 MHz, internal standard CDCl ₃ ) was measured. The chemical shift δ (ppm) was as follows. Gluconolactone (II) -c: ¹ H-NMR (400 MHz, CDC
l ₃ ) δ / ppm 3.41 (s, 3H), 3.51 (s, 3H), 3.53 (s,
3H), 3.57 (s, 3H), 3.10 to 3.90 (m, 5
H) 4.50 (ddd, 1H) Gluconolactone (II) -c 100 parts by weight was heated to 160 ° C under a nitrogen atmosphere, and here, 0.2 (parts by weight) of di (butoxy) zinc as a polymerization catalyst and polymerization initiation An aliphatic polyester was synthesized by adding 0.5 parts by weight of methanol as an agent. The polymerization time was 4 hours.

The weight average molecular weight of the obtained aliphatic polyester was 780,000 in terms of polystyrene, and the average degree of polymerization was 33.
30. (Example 4) D obtained from starch in the same manner as in Example 1
After adding 300 parts by weight of glucose to 1100 parts by weight of methanol containing hydrogen chloride (0.25% by weight), the mixture was refluxed for 72 hours to obtain 160 parts by weight of methyl-D-glucose.

¹³ C-NM of synthesized methyl-D-glucose
R (100 MHz, internal standard DMSO-d ₆ ) was measured. The chemical shift δ (ppm) was as follows. Methyl-D-glucose: ¹³ C-NMR (100 MHz, DMSO-d
₆ ) δ / ppm 99.57, 73.33, 72.49, 71.90, 70.
31, 60.54, 54.22 In 2900 parts by weight of dimethyl sulfoxide and 290 parts by weight of a 50% aqueous sodium hydroxide solution, 160 parts by weight of methyl-D-glucose were added to 540 parts by weight of ethyl bromide at room temperature.
For 1-methyl-2,3,4,6-tetra-
197 parts by weight of O-ethyl-D-glucose were obtained.

The synthesized 1-methyl-2,3,4,6-te
Of tra-O-ethyl-D-glucose ¹H-NMR (400MHz,
Internal standard CDCl_Three) Was measured. The chemical shift δ (ppm) is
It was as follows. 1-methyl-2,3,4,6-tetra-O-ethyl-D-glucose
Su:¹H-NMR (400 MHz, CDCl_Three) / Ppm 1.15-1.24 (m, 12H), 3.38 (s, 3H),
3.24 to 3.88 (m, 14H), 4.76 (d, 1H) 1-methyl-2,3,4,6-tetra-O-ethyl-D-
197 parts by weight of glucose and 18 of trimethylsilyl azide 18
5 parts by weight were dissolved in 1330 parts by weight of methylene chloride,
Methylene chloride solution containing 400 parts by weight of tin tetrachloride
640 parts by weight are slowly added dropwise and stirred at room temperature for 22 hours.
And reacted. After completion of the reaction, 1800 parts by weight of water was added,
Extracted with hexane. Then, the reaction mixture is
Separated and purified by chromatography and represented by the following chemical formula (II) -d
150 parts by weight of gluconolactone to be obtained.

[0063]

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¹ H-NM of synthesized gluconolactone (II) -d
R (400 MHz, internal standard CDCl ₃ ) was measured. The chemical shift δ (ppm) was as follows. Gluconolactone (II) -d: ¹ H-NMR (400 MHz, CDC
l ₃ ) δ / ppm 1.16 to 1.33 (m, 12H), 3.45 to 3.89
(m, 12H), 3.93 ( ABX 3 -dq, 1H), 4.3
100 parts by weight of 2 (dt, 1H) gluconolactone (II) -d were heated to 160 ° C. under a nitrogen atmosphere, and 0.4 parts by weight of tetra (butoxy) titanium as a polymerization catalyst and 1,8 parts as a polymerization initiator were added thereto. -Aliphatic polyester was synthesized by adding 0.6 parts by weight of octanediol. The polymerization time was 4 hours.

The weight average molecular weight of the obtained aliphatic polyester was 1.06 million in terms of polystyrene, and the average degree of polymerization was 3
660.

¹³ C-NMR of synthesized aliphatic polyester
(100 MHz, internal standard CDCl ₃ ) was measured. The chemical shift δ (ppm) was as follows. Aliphatic polyester: ¹³ C-NMR (100 MHz, CDCl ₃ ) δ
/ Ppm 15.11, 15.28, 15.43, 15.56, 67.
05, 67.18, 67.45, 67.72, 68.64,
76.20, 78.22, 78.87, 81.31, 17
3.57 (Evaluation of Physical Properties) Various physical properties were evaluated using the aliphatic polyesters synthesized in Examples 1 to 4. Table 1 shows the results. As a reference example, a comparative study was performed using Cell Green (manufactured by Daicel Chemical Industries, polycaprolactone plastic, P-H7).

[0067]

[Table 1]

From the above results, each of the aliphatic polyesters synthesized in Examples 1 to 4 was obtained from Daicel Chemical's aliphatic polyester (PH
It has physical properties equivalent to or better than 7), and it can be seen that it can be sufficiently used as a substitute for a conventionally known plastic molded product.

[0069]

As described above, according to the present invention,
A high-molecular-weight aliphatic polyester can be produced by ring-opening polymerization of gluconolactone obtained from starch via D-glucose, and its physical properties such as mechanical strength are sufficient and used as a plastic molded product. be able to. In addition, this opens the way to the efficient use of starch as a source of high-quality plastics starting from starch instead of petroleum.

[Brief description of the drawings]

FIG. 1 is a diagram showing an infrared absorption spectrum of an aliphatic polyester synthesized in Example 1.

FIG. 2 is a view showing an infrared absorption spectrum of an aliphatic polyester synthesized in Example 2.

Claims (5)

[Claims] [Claim 1] The following general formula (1) (In the formula, R is a hydrogen atom, an acetyl group, or a group having 1 to 1 carbon atoms.
3 represents a linear or branched alkyl group. An aliphatic polyester having a structural unit represented by the formula: 2. The following general formula (I): (Wherein, R is a hydrogen atom, an acetyl group, or a
3 represents a linear or branched alkyl group. n represents an integer of 3 to 20,000. The aliphatic polyester according to claim 1, which is represented by the formula: 3. The following general formula (I): (In the formula, R is a hydrogen atom, an acetyl group, or a group having 1 to 1 carbon atoms.
3 represents a linear or branched alkyl group. n represents an integer of 3 to 20,000. A process for producing an aliphatic polyester represented by the following general formula (II): (Wherein, R is a hydrogen atom, an acetyl group, or a group having 1 to 1 carbon atoms)
3 represents a linear or branched alkyl group. A process for producing an aliphatic polyester, which comprises a step of ring-opening polymerization of gluconolactone represented by the formula (1). (4) a step of hydrolyzing starch to obtain D-glucose, and (ii) a step of preparing the following general formula (II) from the D-glucose: (Wherein, R is a hydrogen atom, an acetyl group, or a group having 1 to 1 carbon atoms)
3 represents a linear or branched alkyl group. A) obtaining a gluconolactone represented by:
The method for producing an aliphatic polyester according to claim 3, further comprising a step of subjecting the gluconolactone to ring-opening polymerization. 5. A method for reclaiming starch, comprising: (i) hydrolyzing starch to obtain D-glucose; (ii)
From the D-glucose, the following general formula (II): (Wherein, R is a hydrogen atom, an acetyl group, or a group having 1 to 1 carbon atoms)
3 represents a linear or branched alkyl group. A) obtaining a gluconolactone represented by:
The gluconolactone is subjected to ring-opening polymerization to give the following general formula (I): (In the formula, R is a hydrogen atom, an acetyl group, or a group having 1 to 1 carbon atoms.
3 represents a linear or branched alkyl group. n represents an integer of 3 to 20,000. A method for recycling starch comprising a step of obtaining an aliphatic polyester represented by the following formula: