JP2023061092A - Method for producing polycarbonate polyol - Google Patents

Abstract

To provide a method for producing a polycarbonate polyol that efficiently yields a polycarbonate polyol useful as a raw material for production of resins such as polyurethane and elastomers without using highly toxic phosgene and under relatively moderate conditions.SOLUTION: A method for producing a polycarbonate polyol causes a polyhydroxy compound to react with a predetermined fluorinated carbonate, with a ratio of the fluorinated carbonate of 0.3 mol or more and less than 1 mol to the polyhydroxy compound of 1 mol, in the presence of a catalyst.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing a polycarbonate polyol useful as a raw material for producing resins such as polyurethanes and elastomers.

Polycarbonate polyols used as raw materials for polyurethane production include, for example, transesterification of aliphatic polyhydroxy compounds such as 1,6-hexanediol with dialkyl carbonates and diaryl carbonates, as described in Patent Documents 1 and 2. Those produced by reaction are common.

On the other hand, as a method for producing a polycarbonate resin, Patent Document 3 discloses that a fluorine-containing carbonate is reacted with an aromatic dihydroxy compound such as bisphenol A to obtain a prepolymer, and the by-product fluorine-containing alcohol is discharged out of the reaction system. A method for solid-state polymerization is disclosed. According to Patent Document 3, according to this production method, a high-molecular-weight polycarbonate resin can be produced with good productivity by solid phase polymerization at a relatively low temperature without using phosgene, which is highly reactive but highly toxic. is described.

JP-A-2-158617 JP-A-2000-95854 WO2014/171367

In conventional methods for producing polycarbonate polyols, such as those described in Patent Documents 1 and 2, transesterification is an equilibrium reaction, so in order to improve reactivity, the reaction is carried out at a high temperature of about 200°C for a long time. I needed it. In addition, in order to promote the reaction, it is necessary to continuously remove alcohol, which is a by-product of the transesterification reaction, out of the reaction system. It had to be carried out under severe conditions such as high temperature, and had problems such as a large equipment burden.

In addition, in the production method described in Patent Document 3, a solid prepolymer for producing a polycarbonate resin by solid phase polymerization is obtained, and in order to facilitate the progress of the solid phase polymerization of the prepolymer, an aromatic dihydroxy compound is used. is reacted with an equimolar or more fluorine-containing carbonate.

Therefore, the present inventors focused on the amounts of the polyhydroxy compound and the fluorine-containing carbonate to be transesterified, and as a result, found a method for producing a polycarbonate polyol suitable for the production of polyurethane, which can solve the above problems. .

That is, the present invention provides a method for producing a polycarbonate polyol that efficiently obtains a polycarbonate polyol useful as a raw material for producing resins such as polyurethanes and elastomers under relatively mild conditions without using highly toxic phosgene. intended to provide

The present invention is based on the discovery that a polycarbonate polyol can be efficiently obtained under relatively mild conditions by reacting a predetermined amount of a polyhydroxy compound and a fluorine-containing carbonate.

式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に、水素原子の一部もしくは全部がフッ素原子で置換された炭素原子数１～１２の含フッ素炭化水素基、又は、エーテル結合を含む前記含フッ素炭化水素基である。
［２］前記反応は、前記ポリヒドロキシ化合物と前記含フッ素カーボネートとのエステル交換反応であり、含フッ素アルコールを副生する、［１］に記載のポリカーボネートポリオールの製造方法。
［３］前記含フッ素アルコールは、２５℃の水中での酸解離定数（ｐＫａ）が１３以下である、［２］に記載のポリカーボネートポリオールの製造方法。
［４］前記ポリヒドロキシ化合物と前記含フッ素カーボネートとを反応させた後に、前記含フッ素アルコールを７０～１３０℃で減圧留去する、［２］又は［３］に記載のポリカーボネートポリオールの製造方法。
［５］前記ポリヒドロキシ化合物と前記含フッ素カーボネートとを、７０～１７０℃で反応させる、［１］～［４］のいずれかに記載のポリカーボネートポリオールの製造方法。
［６］前記含フッ素カーボネートは、前記式（１）における含フッ素炭化水素基がフルオロアルキル基である、［１］～［５］のいずれかに記載のポリカーボネートポリオールの製造方法。
［７］前記含フッ素カーボネートが、ビス（１，１，１－トリフルオロエチル）カーボネート、ビス（１，１，１，３，３，３－ヘキサフルオロイソプロピル）カーボネート及びビス（ペルフルオロ－ｔ－ブチル）カーボネートから選ばれる１種以上である、［１］～［６］のいずれかに記載のポリカーボネートポリオールの製造方法。
［８］前記ポリヒドロキシ化合物が、脂肪族ポリヒドロキシ化合物である、［１］～［７］のいずれかに記載のポリカーボネートポリオールの製造方法。
［９］前記脂肪族ポリヒドロキシ化合物が、飽和炭化水素ポリオール、ポリエーテルポリオール、ポリエステルポリオール、ポリオレフィンポリオール及びアクリルポリオールから選ばれる１種以上である、［８］に記載のポリカーボネートポリオールの製造方法。
［１０］前記触媒が、第三級アミンである、［１］～［９］のいずれかに記載のポリカーボネートポリオールの製造方法。
［１１］前記ポリカーボネートポリオールの重量平均分子量が３００～５００００である、［１］～［１０］のいずれかに記載のポリカーボネートポリオールの製造方法。 The present invention provides the following means.
[1] A polyhydroxy compound and a fluorine-containing carbonate represented by the following formula (1) are added at a ratio of 0.3 mol or more and less than 1 mol of the fluorine-containing carbonate to 1 mol of the polyhydroxy compound, and a catalyst A method for producing a polycarbonate polyol, which is reacted in the presence of.

In formula (1), R ¹ and R ² each independently contain a fluorine-containing hydrocarbon group having 1 to 12 carbon atoms in which some or all of the hydrogen atoms are substituted with fluorine atoms, or an ether bond. It is the fluorine-containing hydrocarbon group.
[2] The method for producing a polycarbonate polyol according to [1], wherein the reaction is a transesterification reaction between the polyhydroxy compound and the fluorine-containing carbonate to produce a fluorine-containing alcohol by-product.
[3] The method for producing a polycarbonate polyol according to [2], wherein the fluorine-containing alcohol has an acid dissociation constant (pKa) of 13 or less in water at 25°C.
[4] The method for producing a polycarbonate polyol according to [2] or [3], wherein after the polyhydroxy compound and the fluorine-containing carbonate are reacted, the fluorine-containing alcohol is distilled off under reduced pressure at 70 to 130°C.
[5] The method for producing a polycarbonate polyol according to any one of [1] to [4], wherein the polyhydroxy compound and the fluorine-containing carbonate are reacted at 70 to 170°C.
[6] The method for producing a polycarbonate polyol according to any one of [1] to [5], wherein the fluorinated hydrocarbon group in the formula (1) is a fluoroalkyl group.
[7] The fluorine-containing carbonate is bis(1,1,1-trifluoroethyl) carbonate, bis(1,1,1,3,3,3-hexafluoroisopropyl) carbonate and bis(perfluoro-t-butyl ) The method for producing a polycarbonate polyol according to any one of [1] to [6], which is one or more selected from carbonates.
[8] The method for producing a polycarbonate polyol according to any one of [1] to [7], wherein the polyhydroxy compound is an aliphatic polyhydroxy compound.
[9] The method for producing a polycarbonate polyol according to [8], wherein the aliphatic polyhydroxy compound is one or more selected from saturated hydrocarbon polyols, polyether polyols, polyester polyols, polyolefin polyols and acrylic polyols.
[10] The method for producing a polycarbonate polyol according to any one of [1] to [9], wherein the catalyst is a tertiary amine.
[11] The method for producing a polycarbonate polyol according to any one of [1] to [10], wherein the polycarbonate polyol has a weight average molecular weight of 300 to 50,000.

INDUSTRIAL APPLICABILITY According to the present invention, a polycarbonate polyol useful as a raw material for producing resins such as polyurethanes and elastomers can be efficiently produced under relatively mild conditions without using highly toxic phosgene.

Definitions and meanings of the terms and expressions used in this specification are shown below.
"Acid dissociation constant (pKa)" is a value determined by a neutralization titration method.
The "hydroxyl value" is determined by measurement according to JIS K1557-1:2007 B method (automatic potentiometric titration method).
The "hydroxyl value equivalent molecular weight" is a value calculated from the formula of 56100×(number of hydroxyl groups in one molecule)/(hydroxyl value).
"Number average molecular weight" (hereinafter referred to as "Mn") and "weight average molecular weight" (hereinafter referred to as "Mw") are based on a calibration curve prepared using a standard polystyrene sample, gel It is a polystyrene equivalent molecular weight determined by permeation chromatography (GPC). "Molecular weight distribution" means the ratio of Mw to Mn (Mw/Mn). Specifically, it is measured by the method described in Examples below.
"(Meth)acrylate" is a generic term for acrylate and methacrylate. Similarly, "(meth)acrylic acid" is a generic term for acrylic acid and methacrylic acid.

In the method for producing a polycarbonate polyol of the present invention, a polyhydroxy compound and a fluorine-containing carbonate represented by the following formula (1) are combined in an amount of 0.3 mol or more and less than 1 mol of the fluorinated carbonate per 1 mol of the polyhydroxy compound. in the presence of a catalyst.

In formula (1), R ¹ and R ² each independently contain a fluorine-containing hydrocarbon group having 1 to 12 carbon atoms in which some or all of the hydrogen atoms are substituted with fluorine atoms, or an ether bond. It is the fluorine-containing hydrocarbon group.

In the present invention, rather than the highly toxic phosgene, dialkyl carbonate, or diaryl carbonate used in the conventional method, a fluorine-containing carbonate is used, and by reacting a predetermined amount with a polyhydroxy compound, relatively mild conditions, a polycarbonate polyol can be obtained efficiently.

[Polyhydroxy compound]
The polyhydroxy compound, which is a raw material for producing the polycarbonate polyol of the present invention, is a compound having two or more hydroxyl groups. A polyhydroxy compound may be used individually by 1 type, or may use 2 or more types together.
The polyhydroxy compound may be an aliphatic polyhydroxy compound or an aromatic polyhydroxy compound. Aliphatic polyhydroxy compounds are preferred when producing polycarbonate polyols used as raw materials for flexible polyurethanes, elastomers, and the like.

Examples of aliphatic polyhydroxy compounds include saturated hydrocarbon polyols, cycloaliphatic hydrocarbon polyols, polyether polyols, polyester polyols, polyolefin polyols, and acrylic polyols. An aliphatic polyhydroxy compound may be used individually by 1 type, or may use 2 or more types together. Among these, one or more selected from saturated hydrocarbon polyols, cycloaliphatic hydrocarbon polyols, polyether polyols, polyester polyols, polyolefin polyols and acrylic polyols are preferred.

Specific examples of saturated hydrocarbon polyols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1, 8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2- ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 2-methyl- 1,8-octanediol, glycerin, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol, sorbitol and the like.
Specific examples of cycloaliphatic hydrocarbon polyols include 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-dimethylolcyclohexane, 2,2′-bis-(4-hydroxycyclohexyl)propane, 2 , 2,4,4-tetramethylcyclobutane-1,3-diol and the like.
Specific examples of polyether polyols include diglycerin, dipentaerythritol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol and the like.
Polyester polyols include, for example, polycondensation of polyhydric alcohol and polycarboxylic acid, polycondensation of hydroxycarboxylic acid, polymerization of cyclic ester (lactone), polyaddition of cyclic ether to polycarboxylic anhydride, polyethylene terephthalate and polyester polyols obtained by the transesterification reaction of.
Specific examples of polyolefin polyols include butadiene polyol.
Examples of acrylic polyols include copolymers of hydroxyalkyl (meth)acrylates and (meth)acrylic acid esters.

Examples of polyether polyol include polypropylene glycol obtained by ring-opening polymerization of propylene oxide in the presence of an alkali catalyst or a double metal cyanide complex catalyst using a low-molecular-weight polypropylene glycol as an initiator to increase the molecular weight. Alternatively, a polymer having a desired molecular weight may be produced and used.

As the aromatic polyhydroxy compound, for example, an aromatic dihydroxy compound having two phenolic hydroxyl groups is preferable. Specifically, bisphenol A, bisphenol AF, hydroquinone, 4,4′-dihydroxybiphenyl, 9,9-bis(4-hydroxyphenyl)fluorene, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl) thioether, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ketone and the like. These may be used individually by 1 type, or may use 2 or more types together.

[Fluorinated carbonate]
The fluorine-containing carbonate to be reacted with the polyhydroxy compound is a compound represented by the following formula (1).

In formula (1), R ¹ and R ² each independently contain a fluorine-containing hydrocarbon group having 1 to 12 carbon atoms in which some or all of the hydrogen atoms are substituted with fluorine atoms, or an ether bond. It is the fluorine-containing hydrocarbon group.
The fluorine-containing hydrocarbon group may have a chain structure or a cyclic structure.
The number of carbon atoms in the fluorine-containing hydrocarbon group is preferably 1-10, more preferably 3-8.

Specific examples of fluorine-containing carbonates include bis(1,1,1-trifluoroethyl) carbonate, bis(1,1,1,3,3,3-hexafluoroisopropyl) carbonate, bis(1,1,1 ,3,3,4,4,4-octafluoro-sec-butyl) carbonate, bis(1,1,1,2,2,4,4,5,5,5-decafluoro-3-pentyl) carbonate , bis(perfluoro-t-butyl) carbonate, bis(2,2,3,3,4,4,5,5-octafluorocyclopentyl) carbonate, bis(2,2,3,3,4,4,5 ,5,6,6-decafluorocyclohexyl)carbonate, bis(perfluorophenyl)carbonate, bis(m-trifluoromethylphenyl)carbonate, bis(o-trifluoromethylphenyl)carbonate, bis(p-trifluoromethylphenyl)carbonate ) carbonate and the like.

The reaction between the polyhydroxy compound and the fluorine-containing carbonate in the production method of the present invention is a polycondensation by transesterification reaction, and it is preferable that the fluorine-containing alcohol is eliminated and a by-product is produced. ¹ OH and R ² OH are preferred.
The fluorine-containing alcohol that is eliminated in the transesterification reaction is preferably a secondary or tertiary fluorine-containing alcohol having a fluoroalkyl group bonded to the α carbon from the viewpoint of promoting the reaction, and from the viewpoint of the stability of the fluorine-containing carbonate. Secondary fluorine-containing alcohols are more preferred from. However, an alcohol in which a fluorine atom is directly bonded to the α carbon is not preferable because it is likely to cause a decomposition reaction accompanied by a dehydrofluorination reaction.

The by-produced fluorine-containing alcohol preferably has an acid dissociation constant (pKa) in water at 25° C. of 13 or less, more preferably 12.5 or less, still more preferably 12 or less, from the viewpoint of promoting the transesterification reaction. Even more preferably, it is 11 or less. Moreover, the pKa of the fluorine-containing alcohol is preferably 5 or more from the viewpoint of the availability of the fluorine-containing carbonate.
When the pKa of the fluorine-containing alcohol is 13 or less, progress of the transesterification reaction is less likely to be inhibited even if the fluorine-containing alcohol is present in the reaction system during the transesterification reaction. Therefore, the production reaction of the polycarbonate polyol proceeds without discharging the fluorine-containing alcohol out of the reaction system during the reaction.

From the viewpoint of reducing the operational burden and production cost in the polycarbonate polyol production process, the fluorine-containing alcohol by-produced by the transesterification reaction is preferably 70 to 130 ° C. after reacting the polyhydroxy compound and the fluorine-containing carbonate. It is more preferably distilled off under reduced pressure at a temperature within the range of 75 to 120°C, more preferably 80 to 110°C.
By distilling off the fluorine-containing alcohol after the transesterification reaction, the reaction can be carried out under relatively mild conditions of normal pressure and 170° C. or lower, and the operation and equipment load during the reaction can be reduced.
From the viewpoint of improving the production efficiency of the polycarbonate polyol, the by-produced fluorine-containing alcohol may be discharged out of the reaction system during the reaction, although this causes an operational burden.

The absolute pressure for distilling off the fluorine-containing alcohol under reduced pressure is preferably 15 kPa or less, more preferably 10 kPa or less, and even more preferably 5 kPa or less. The temperature is preferably 70 to 130°C, more preferably 70 to 120°C, still more preferably 80 to 120°C, from the viewpoint of reducing production costs.

The by-produced fluorine-containing alcohol preferably has a relatively low boiling point in order to be distilled off. From this point of view, the fluorine-containing hydrocarbon group in the above formula (1) is preferably a part of hydrogen atoms. It is also a fluoroalkyl group or a cyclofluoroalkyl group in which all or all of the hydrogen atoms are substituted with fluorine atoms, and more preferably a fluoroalkyl group in which some or all of the hydrogen atoms are substituted with fluorine atoms.
Examples of fluorine-containing alcohols include 1,1,1-trifluoroethanol (pKa=12.4), 1,1,1,3,3,3-hexafluoroisopropanol (pKa=9.4), 1, 1,1,3,3,4,4,4-octafluoro-sec-butanol (pKa=9.5), 1,1,1,2,2,4,4,5,5,5-decafluoro -3-pentanol (pKa = 10.6), perfluoro(t-butyl) alcohol (pKa = 5.3), 2,2,3,3,4,4,5,5-octafluorocyclopentanol ( pKa=7.4), 2,2,3,3,4,4,5,5,6,6-decafluorocyclohexanol (pKa=6.8).

Among the above specific examples, the fluorine-containing carbonate is preferably bis(1,1,1-trifluoroethyl) carbonate, bis(1,1,1,3,3,3-hexafluoroisopropyl) carbonate, bis (1,1,1,3,3,4,4,4-octafluoro-sec-butyl) carbonate, bis(1,1,1,2,2,4,4,5,5,5-decafluoro -3-pentyl) carbonate, bis(perfluoro-t-butyl) carbonate, bis(2,2,3,3,4,4,5,5-octafluorocyclopentyl) carbonate and bis(2,2,3,3 , 4,4,5,5,6,6-decafluorocyclohexyl) carbonate, more preferably bis(1,1,1-trifluoroethyl) carbonate, bis(1,1 , 1,3,3,3-hexafluoroisopropyl) carbonate and bis(perfluoro-t-butyl) carbonate, and from the viewpoint of availability, bis(1,1,1,3 ,3,3-hexafluoroisopropyl)carbonate is particularly preferred.

A fluorine-containing carbonate can be produced, for example, by a known method such as reacting a fluorine-containing alcohol (R ¹ OH and R ² OH) with phosgene as a raw material, and is described in International Publication No. 2018/211953. It can be produced by a method of irradiating light using a halogenated hydrocarbon and oxygen such as The latter method is more preferable because it can be produced safely and efficiently without using highly toxic phosgene.
As the fluorine-containing alcohol, which is a raw material for producing the fluorine-containing carbonate, the fluorine-containing alcohol by-produced in the production method of the present invention can be recycled and used.

[catalyst]
In the production method of the present invention, a catalyst is used to promote the transesterification reaction between the polyhydroxy compound and the fluorine-containing carbonate. Preferred examples of the catalyst include basic transesterification catalysts such as nitrogen-containing compounds, alkali metal compounds, Group 2 element (magnesium or alkaline earth metal) compounds. A catalyst may be used individually by 1 type, or may use 2 or more types together.

Specific examples of nitrogen-containing compounds include tertiary amines such as triethylamine, tripropylamine, tributylamine, triisoamylamine, trihexylamine, triheptylamine, trioctylamine, tridodecylamine, and triethylenediamine; ,3,3-tetramethylguanidine; 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole compounds such as benzimidazole, pyridine, 2,6-dimethylpyridine, 2,4,6-trimethylpyridine, N - monocyclic heterocyclic compounds such as methylmorpholine; 1,5-diazabicyclo[4.3.0]non-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, etc. Cyclic heterocyclic compounds; quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide.

Specific examples of alkali metal compounds include sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, sodium hydrogen carbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, sodium acetate, potassium acetate, cesium acetate, Lithium Acetate, Sodium Stearate, Potassium Stearate, Cesium Stearate, Lithium Stearate, Sodium Borohydride, Sodium Phenylborohydride, Sodium Phenylborohydride, Sodium Benzoate, Potassium Benzoate, Cesium Benzoate, Lithium Benzoate, Disodium hydrogen phosphate, dipotassium hydrogen phosphate, disodium phenyl phosphate, sodium gluconate, sodium phenoxide, potassium phenoxide, cesium phenoxide, lithium phenoxide and the like.

Specific examples of Group 2 element compounds include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium hydrogen carbonate, calcium hydrogen carbonate, strontium hydrogen carbonate, barium hydrogen carbonate, magnesium carbonate, calcium carbonate, and carbonate. Strontium, barium carbonate, magnesium acetate, calcium acetate, strontium acetate, barium acetate, magnesium stearate, calcium stearate, calcium benzoate, magnesium phenylphosphate and the like.
Among these, tertiary amines are preferable from the viewpoints of easiness of control of suppression of thickening by increasing the molecular weight, and ease of obtaining a polycarbonate polyol having a narrow molecular weight distribution.

The amount of the catalyst used in the reaction between the polyhydroxy compound and the fluorine-containing carbonate is preferably from 0.01 to 0.01 with respect to a total of 100 parts by mass of the polyhydroxy compound and the fluorine-containing carbonate, from the viewpoint of appropriately promoting the transesterification reaction. 10 parts by mass, more preferably 0.05 to 8 parts by mass, still more preferably 0.1 to 5 parts by mass.

The basic transesterification catalyst is preferably removed or deactivated as necessary after the reaction between the polyhydroxy compound and the fluorine-containing carbonate. The removal or deactivation treatment can be carried out by a known method for removing or deactivating a basic catalyst. An adsorption method using an adsorbent such as clay can be applied. A neutralization method using an organic acid or a mineral acid can also be applied, and the neutralization method and the adsorption method may be used in combination.

[Reaction conditions]
In the production method of the present invention, the fluorine-containing carbonate is added in an amount of 0.3 mol or more and less than 1 mol, preferably 0.35 to 0.99 mol, more preferably 0.4 to 0.4 mol, per 1 mol of the polyhydroxy compound. It is reacted in a proportion of 98 mol.
If the fluorine-containing carbonate is less than 0.3 mol with respect to 1 mol of the polyhydroxy compound, the resulting polycarbonate polyol tends to have a high molecular weight and becomes difficult to control the reaction due to increased viscosity. difficult to remove. On the other hand, if the amount of the fluorine-containing carbonate is 1 mol or more, the hydroxyl groups of the polyhydroxy compound are blocked with the fluorine-containing hydrocarbon groups of the fluorine-containing carbonate, making it impossible to obtain a polycarbonate polyol.

The reaction temperature between the polyhydroxy compound and the fluorine-containing carbonate is preferably 70 to 170° C., more preferably 80 to 170° C., from the viewpoint of sufficiently promoting polycondensation due to transesterification and suppressing side reactions such as decarboxylation. 160°C, more preferably 90 to 150°C.
The reaction time is preferably 1 to 24 hours, more preferably 2 to 20 hours, and still more preferably 3 to 18 hours, from the viewpoints of an appropriate degree of polymerization and suppression of coloration due to heat history of the resulting polycarbonate polyol.
Although the reaction temperature may be constant, it is also preferable to raise the temperature of the reaction system in the middle from the viewpoint of homogenizing the reaction system and promoting the reaction. For example, the polyhydroxy compound, the fluorine-containing carbonate and the catalyst are stirred and mixed at 70 to 100° C. for about 1 to 5 hours to sufficiently homogenize the reaction system, and then the temperature is raised to 100 to 170° C., The reaction may be allowed to proceed.

As described above, in the production method of the present invention, the fluorine-containing alcohol that is eliminated by polycondensation due to the transesterification reaction proceeds without being removed from the reaction system during the reaction. reactions can be carried out.

[Polycarbonate polyol]
The polycarbonate polyol obtained by the production method of the present invention preferably has a weight-average molecular weight (Mw) of 300 to 50,000, more preferably 300 to 50,000, from the viewpoint of usefulness as a raw material for producing resins such as polyurethanes and elastomers, viscosity that is easy to handle, and the like. It is preferably 350 to 40,000, more preferably 400 to 30,000.

According to the production method of the present invention, a polycarbonate polyol can be easily produced as a block polymer in which polyhydroxy compounds are linked by carbonate bonds. Therefore, the production method of the present invention is useful in designing the structure of polycarbonate polyols, which are raw materials for producing resins such as polyurethanes and elastomers having desired physical properties.
Polycarbonate polyols obtained by the production method of the present invention are useful, for example, for producing polyurethanes, elastomers, and the like having excellent tensile properties.

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples.

[Production of Polycarbonate Polyol]
In Examples 1-3, polycarbonate polyols were prepared.
Details of methods for measuring various physical properties, raw materials and materials used are as follows.

〔Measuring method〕
(Number average molecular weight, weight average molecular weight and molecular weight distribution)
The number average molecular weight (Mn) and weight average molecular weight (Mw) are measured by gel permeation chromatography (GPC) under the following conditions (converted to polystyrene), and the molecular weight distribution (Mw/Mn) is calculated from these values. bottom. Examples 1 and 2 were measured under condition 1 below, and examples 3 and 4 were measured under condition 2 below.
<Condition 1>
・Equipment used: “HLC-8220GPC” manufactured by Tosoh Corporation ・Column used: “TSKgel (registered trademark; hereinafter the same.) SuperHZ4000” two are connected in series, manufactured by Tosoh Corporation ・Eluent: concentration 0.1 mol /L of triethylamine in tetrahydrofuran Flow rate: 0.35 mL/min Detector: Differential refractive index (RI) and ultraviolet absorption (UV)
・Column temperature: 40°C
・ Sample concentration: 0.05 g / TFH 10 mL
・Sample injection volume: 20 μL
<Condition 2>
・Equipment used: "HLC-8320GPC", manufactured by Tosoh Corporation ・Column used: Two "TSKgel SuperHZ4000" and two "TSKgel SuperHZ2500" connected in series, both manufactured by Tosoh Corporation ・Eluent: Tetrahydrofuran ・Flow rate: 0 .35 mL/min Detectors: RI and UV
・Column temperature: 40°C
・ Sample concentration: 0.05 g / TFH 10 mL
・Sample injection volume: 20 μL

(hydroxyl value)
The hydroxyl value was measured according to JIS K1557-1:2007 B method (automatic potentiometric titration method).

(amount of water)
The water content was measured in accordance with JIS K1557-2:2007 B method.

[Raw materials and materials used]
BHFC: bis (1,1,1,3,3,3-hexafluoroisopropyl) carbonate; fluorinated carbonate synthesized in Synthesis Example 1 below 1,6-hexanediol; manufactured by Tokyo Chemical Industry Co., Ltd. PPG (1): Polypropylene glycol obtained by ring-opening polymerization of propylene oxide in the presence of a zinc hexacyanocobaltate complex using polypropylene glycol having a molecular weight of about 1000 as an initiator; hydroxyl value 56.0 mgKOH/g, hydroxyl value equivalent molecular weight 2000, water content 30ppm
· PTMG: polytetramethylene oxide 650; manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Mn 800, Mw 1000, Mw / Mn 1.25
・ DABCO: 1,4-diazabicyclo [2.2.2] octane (also known as triethylenediamine); manufactured by Tokyo Chemical Industry Co., Ltd. ・ KW600: Synthetic magnesium silicate; “Kyoward (registered trademark) 600”, Kyowa Chemical Industry Manufactured by Co., Ltd. KW700SL: Synthetic aluminum silicate; "Kyoward (registered trademark) 700SL", manufactured by Kyowa Chemical Industry Co., Ltd.

(Synthesis example 1)
Synthesis of BHFC was performed with reference to the method described in WO2018/211953.
To 1 mol part of chloroform, 1 mol part of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 1.5 mol part of pyridine are added, and while stirring and mixing, oxygen is added at 20 ° C. The gas was bubbled at a flow rate of 0.5 L/min, and irradiated with light from a 20 W low-pressure mercury lamp at 30°C. After reacting for 10 hours, chloroform, hydrochloric acid and water were added to separate the layers, and the organic phase was dried over anhydrous sodium sulfate and purified by distillation to obtain BHFC (yield 65%).

[Example 1]
25 g (69.1 mmol) of BHFC, 16 g (135.6 mmol) of 1,6-hexanediol, and 0.8 g (7 mmol) of DABCO as a catalyst were added to a 300 mL three-necked flask equipped with a thermometer, Liebig condenser and a fractionating Vigreux. ) was charged and stirred at 90° C. under normal pressure with a magnetic stirrer for 3 hours, then heated to 130° C. and reacted for 14 hours.
Then, the by-produced fluorine-containing alcohol was distilled off under reduced pressure at 90° C. and 1.3 kPa to obtain polycarbonate polyol (1) (product) having terminal hydroxyl groups (Mn 291, Mw 452, Mw/Mn 1.0). 55).
Incidentally, ¹ H NMR measurement of the deuterated chloroform solution showed that the product did not contain BHFC (chemical shift (δ) 5.56 ppm) and HFIP (δ 4.37 ppm), and that the distillate was HFIP ( δ 4.37 ppm).

[Example 2]
In the reactor of Example 1, the Liebig condenser tube and the fractionating tube Vigreux were replaced with a glass bent calcium tube filled with calcium chloride. A three-necked flask was charged with 5 g (13.8 mmol) of BHFC, 30.4 g (15.2 mmol) of PPG (1), and 0.8 g (7 mmol) of DABCO as a catalyst. After stirring for 1 hour, the temperature was raised to 130° C. and the mixture was reacted for 7 hours.
Then, the by-produced fluorine-containing alcohol was distilled off under reduced pressure at 90° C. and 1.3 kPa to obtain polycarbonate polyol (2) having terminal hydroxyl groups (Mn 4000, Mw 5200, Mw/Mn 1.30).

[Example 3]
In the same reactor as in Example 2, 50 g (138 mmol) of BHFC, 102 g (146 mmol) of PTMG, and 1.06 g (9.5 mmol) of DABCO as a catalyst were charged in a three-necked flask, and magnetically reacted at 90°C under normal pressure. After stirring with a stirrer for 3 hours, the mixture was heated to 130° C. and reacted for 6 hours.
Then, the by-produced fluorine-containing alcohol is distilled off under reduced pressure at 90° C. and 1.3 kPa, and KW600 and KW700SL as alkaline adsorbents are added to the residual liquid at 5 parts by weight each per 100 parts by weight of the residual liquid, After stirring at 90°C for 30 minutes, filter paper No. Pressure filtration was performed using 5C to obtain polycarbonate polyol (3) (product) having terminal hydroxyl groups (hydroxyl value: 23.0 mgKOH/g, Mn: 3800, Mw: 7800, Mw/Mn: 2.05).
¹ H NMR measurement of the deuterated chloroform solution confirmed that the product did not contain BHFC and HFIP. ¹³ C NMR measurement also confirmed the presence of carbonate groups (δ 115.92 ppm and 65.05 ppm).

[Example 4]
In the same reactor as in Example 2, 6.1 g (69 mmol) of ethylene carbonate, 51 g (73 mmol) of PTMG, and 1.06 g (9.5 mmol) of DABCO as a catalyst were charged in a three-necked flask, and the reaction was carried out at 90°C under normal pressure. After stirring with a magnetic stirrer for 3 hours, the mixture was heated to 130° C. and reacted for 6 hours.
Next, the alcohol is distilled off under reduced pressure at 90° C. and 1.3 kPa, and KW600 and KW700SL as alkaline adsorbents are added to the residual liquid at 5 parts by weight each per 100 parts by weight of the residual liquid, and the mixture is heated at 90° C. for 30 minutes. After stirring, filter paper no. The product was filtered under pressure using 5C (hydroxyl value 150 mgKOH/g, Mn 900, Mw 1100, Mw/Mn 1.22).
It was confirmed that under the same conditions as in Example 3, when ethylene carbonate was used in place of BHFC, the reaction hardly proceeded.

[Manufacture of Polyurethane]
A polyurethane was produced using the polycarbonate polyol (3) obtained in Example 3, and its tensile properties were measured and evaluated.
The details of the raw materials used in the method of measuring and evaluating tensile properties and the production of polyurethane are as follows.

[Measurement evaluation of tensile properties]
A test piece was prepared from the polyurethane film according to JIS K7311: 1995, and a tensile test (temperature 23 ° C., relative humidity 50%, tensile speed 300 mm / min) was performed, and tensile strength (breaking strength) was obtained as tensile properties. [MPa], stress at 50% elongation [MPa] and elongation [%] were measured.

[Raw materials used]
· 1,4-butanediol; manufactured by Tokyo Chemical Industry Co., Ltd. · PPG (2): Obtained by ring-opening polymerization of propylene oxide in the presence of a zinc hexacyanocobaltate complex using polypropylene glycol having a molecular weight of about 1000 as an initiator. Polypropylene glycol; hydroxyl value 27.9 mgKOH / g, hydroxyl value equivalent molecular weight 4000
・ “Neostan (registered trademark) U-100”; manufactured by Nitto Kasei Co., Ltd., dibutyltin compound curing catalyst ・ “Duranate (registered trademark) D101”: hexamethylene diisocyanate-based bifunctional prepolymer, manufactured by Asahi Kasei Corporation, isocyanate Group (NCO) content 19.7% by mass

[Example 5]
10 parts by mass of the polycarbonate polyol (3) obtained in Example 3, 1,4-butanediol as a chain extender, Duranate D101, and 0.1 part by mass of Neostan U-100 as a catalyst were mixed, defoamed and heated to 80°C. for 24 hours to obtain a polyurethane.
The amount of Duranate D101 (polyisocyanate compound) added was such that the percentage (NCO index) of the number of moles of isocyanate groups to the total number of moles of hydroxyl groups of the polycarbonate polyol (3) and the chain extender was 45.
The obtained polyurethane was pressed at 190-200° C. to form a film having a thickness of 20 μm.
This film had a tensile strength of 15.6 MPa, a stress at 50% elongation of 12.9 MPa, and an elongation of 124%.

[Example 6]
For comparison, a polyurethane film was obtained in the same manner as in Example 5 except that polycarbonate polyol (3) was changed to polyether polyol (PPG (2)).
This film had a tensile strength of 2.9 MPa, a stress at 50% elongation of 1.7 MPa, and an elongation of 170%.

It was confirmed that when the polycarbonate polyol obtained by the production method of the present invention was used as the starting polyol for polyurethane, a polyurethane having excellent tensile properties could be produced.

Claims (11)

A polyhydroxy compound and a fluorine-containing carbonate represented by the following formula (1) are added in the presence of a catalyst at a ratio of 0.3 mol or more and less than 1 mol of the fluorine-containing carbonate per 1 mol of the polyhydroxy compound. A method for producing a polycarbonate polyol by reacting with.

In formula (1), R ¹ and R ² each independently contain a fluorine-containing hydrocarbon group having 1 to 12 carbon atoms in which some or all of the hydrogen atoms are substituted with fluorine atoms, or an ether bond. It is the fluorine-containing hydrocarbon group. 2. The method for producing a polycarbonate polyol according to claim 1, wherein the reaction is a transesterification reaction between the polyhydroxy compound and the fluorine-containing carbonate, and produces a fluorine-containing alcohol by-product. The method for producing a polycarbonate polyol according to claim 2, wherein the fluorine-containing alcohol has an acid dissociation constant (pKa) of 13 or less in water at 25°C. 4. The method for producing a polycarbonate polyol according to claim 2, wherein the fluorine-containing alcohol is distilled off under reduced pressure at 70 to 130° C. after the polyhydroxy compound and the fluorine-containing carbonate are reacted. The method for producing a polycarbonate polyol according to any one of claims 1 to 4, wherein the polyhydroxy compound and the fluorine-containing carbonate are reacted at 70 to 170°C. The method for producing a polycarbonate polyol according to any one of claims 1 to 5, wherein the fluorinated hydrocarbon group in the formula (1) of the fluorinated carbonate is a fluoroalkyl group. The fluorine-containing carbonate is selected from bis(1,1,1-trifluoroethyl) carbonate, bis(1,1,1,3,3,3-hexafluoroisopropyl) carbonate and bis(perfluoro-t-butyl) carbonate The method for producing a polycarbonate polyol according to any one of claims 1 to 6, wherein one or more are selected. The method for producing a polycarbonate polyol according to any one of claims 1 to 7, wherein the polyhydroxy compound is an aliphatic polyhydroxy compound. The method for producing a polycarbonate polyol according to claim 8, wherein the aliphatic polyhydroxy compound is one or more selected from saturated hydrocarbon polyols, polyether polyols, polyester polyols, polyolefin polyols and acrylic polyols. The method for producing a polycarbonate polyol according to any one of claims 1 to 9, wherein the catalyst is a tertiary amine. The method for producing a polycarbonate polyol according to any one of claims 1 to 10, wherein the polycarbonate polyol has a weight average molecular weight of 300 to 50,000.