KR101362885B1 - Aromatic carbonate, method for preparing thereof and polycarbonate using the same - Google Patents

Abstract

(상기에서 R1 및 R2는 각각 독립적으로 수소, 탄소수 1~6의 알킬기임 )The method for preparing an aromatic carbonate from the dialkyl carbonate of the present invention is characterized by comprising reacting an aromatic hydroxy compound with a dialkyl carbonate in the presence of a catalyst represented by the following formula (1) or (2):
[Chemical Formula 1]
SmX ₃
(Wherein X is alkoxy of 1 to 10 carbon atoms, alkylphenoxy or phenoxy)
(2)

(In the above, R1 and R2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms)

Description

Aromatic carbonate, its manufacturing method and polycarbonate using the same {AROMATIC CARBONATE, METHOD FOR PREPARING THEREOF AND POLYCARBONATE USING THE SAME}

The present invention relates to an aromatic carbonate, a method for producing the same, and a polycarbonate using the same. More specifically, the present invention relates to aromatic carbonates prepared using specific catalysts and polycarbonates using the same.

Aromatic carbonates are useful monomers for the production of polycarbonates and many studies have been conducted on their preparation. Conventionally, it has been mainly prepared by the phosgene method in which an aromatic carbonic ester is obtained by reacting phenol and phosgene in the presence of an alkali. However, this method has a problem in that it is necessary to use poisonous phosgene and neutral salt which is a by-product must be treated by the reaction.

Therefore, in order to solve these drawbacks, an ester exchange method for producing an aromatic carbonic ester by reacting an aliphatic carbonic ester such as dimethyl carbonate with phenol has been developed. Such ester exchange processes are generally carried out in the presence of a catalyst, and as the catalyst to be used, PbO, TiX4 (X = alkoxy group or aryloxy group) and SnR2 (OPh) 2 (R = alkyl group) are known. However, in the case of PbO catalyst, the reaction rate is very slow due to high stability but low activity of the catalyst. TiX4 and SnR2 (OPh) 2 have higher activity than PbO catalyst but lack stability, and a considerable amount of ether is obtained as a by-product.

On the other hand, a method of producing an aromatic carbonate by carbonylating an aromatic hydroxy compound using carbon monoxide and oxygen has been developed. However, the method of synthesizing carbon monoxide with carbon monoxide as a starting material has a considerable decrease in reactivity, There is a problem that it is still difficult to commercialize it.

Therefore, there is a need for the development of a method for producing an aromatic carbonate in a stable and high yield using a dialkyl carbonate other than carbon monoxide as a starting material.

An object of the present invention is to provide a process for producing an aromatic carbonate having a dialkyl carbonate as a reaction raw material instead of carbon monoxide.

Another object of the present invention is to provide a process for producing aromatic carbonates in high yield.

Still another object of the present invention is to provide a method capable of effectively producing diaryl carbonates by having a high catalytic activity compared to the existing catalyst system to speed up the esterification reaction of dialkyl carbonate.

Still another object of the present invention is to provide a polycarbonate using a diaryl carbonate prepared by the above method.

The technical objects to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical subjects which are not mentioned can be understood by those skilled in the art from the following description.

One aspect of the invention relates to a process for the preparation of aromatic carbonates from dialkyl carbonates. The method includes reacting an aromatic hydroxy compound with a dialkyl carbonate in the presence of at least one samarium based catalyst represented by Formula 1 or Formula 2 below:

[Formula 1]

SmX ₃

(Wherein X is alkoxy of 1 to 10 carbon atoms, alkylphenoxy or phenoxy)

(2)

(In the above, R1 and R2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms)

The catalyst may be used in 1 × 10 ⁻⁵ to 5 × 10 ⁻¹ moles per mole of dialkyl carbonate.

In embodiments, the reaction may be carried out at a temperature of 100 to 280 ℃.

In an embodiment, the reaction can be carried out in a reactor filled with molecular sieves.

In an embodiment, the aromatic hydroxy compound may be represented by the following Formula 3:

(3)

Ar-OH

(Wherein Ar is a substituted or unsubstituted aryl group).

In embodiments, the dialkyl carbonate may be represented by the following formula (4):

[Chemical Formula 4]

(Wherein R ₁ and R ₂ are each an alkyl group having 1 to 6 carbon atoms and are the same or different from each other).

Another aspect of the invention relates to aromatic carbonates synthesized using the above process. The aromatic carbonate is characterized in that synthesized using at least one samarium-based catalyst represented by the formula (1) or (2).

Another aspect of the present invention relates to a polycarbonate resin polymerized from the aromatic carbonate obtained from the above.

The present invention can produce aromatic carbonate with high yield even at low reaction temperature using dialkyl carbonate rather than carbon monoxide as a raw material, and has higher catalytic activity than existing catalyst system, thereby speeding up the esterification of dialkyl carbonate. It has the effect of the invention to provide a polycarbonate using a method and a method capable of producing a diaryl carbonate to speed up effectively.

1 is a process diagram for preparing a polycarbonate according to one embodiment of the present invention.

A method for preparing an aromatic carbonate from the dialkyl carbonate of the present invention comprises reacting an aromatic hydroxy compound with a dialkyl carbonate in the presence of at least one samarium-based catalyst represented by the following general formula (1) or (2):

[Formula 1]

SmX ₃

(Wherein X is alkoxy of 1 to 10 carbon atoms, alkylphenoxy or phenoxy)

(2)

(In the above, R1 and R2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms)

In an embodiment, X can be methoxy, ethoxy, isopropoxy, butoxy, phenoxy, 2.6-di-tert-butyl-4-methylphenoxy and the like. These may be used alone or in combination of two or more. It is also possible to use a mixture of the catalyst represented by the formula (1) or formula (2).

In an embodiment, the catalyst is from 1 × 10 ⁻⁵ to 5 × 10 ⁻¹ moles , preferably with respect to 1 mole of dialkyl carbonate 5 × 10 ^-5 to 5 × 10 ^-2 moles can be used. The catalyst efficiency is excellent in the above range, and is preferable even in the case where the catalyst is recycled.

The aromatic hydroxy compound may be represented by the following Formula 3:

(3)

Ar-OH

(Wherein Ar is a substituted or unsubstituted aryl group).

Ar may be a phenyl group or a naphthyl group, and the substituent may be alkyl of 1-4 carbon atoms, halogen, alkoxy, nitro, cyano, and the like.

In an embodiment, examples of the aromatic hydroxy compound include, but are not limited to, phenol, naphthol, cresol, chlorophenol, alkylphenol, alkoxyphenol, nitrophenol, cyanophenol and the like. Double phenols are preferably used.

The dialkyl carbonate may be represented by the following formula (4):

[Chemical Formula 4]

(Wherein R ₁ and R ₂ are each an alkyl group having 1 to 6 carbon atoms and are the same or different from each other).

Examples of the dialkyl carbonate include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, and the like. A double dimethyl carbonate can be preferably used.

In embodiments, the reaction may be carried out at a temperature of 100 to 280 ℃, preferably 120 to 250 ℃, more preferably 180 to 240 ℃. Within this range, diaryl carbonate can be obtained in high yield.

The transesterification reaction of the present invention can be carried out at a pressure of 760 mmHg to 15000 mmHg. Preferably the transesterification reaction may proceed at 760 mmHg to 7500 mmHg.

The reaction time is not particularly limited, and may be generally reacted with 1 second to 150 minutes.

The aromatic carbonates prepared from the process can be preferably applied to polycarbonate polymerization. Examples of the aromatic carbonates include diphenyl carbonate, ditoryl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, and the like, but are not limited thereto. These may be used alone or in combination of two or more, preferably diphenyl carbonate.

In one embodiment, the polycarbonate may be prepared by transesterifying the aromatic carbonate obtained above with an aromatic dihydroxy compound.

For example, a first step of producing an aromatic carbonate by reacting an aromatic hydroxy compound and a dialkyl carbonate in the presence of at least one samarium-based catalyst represented by Formula 1 or Formula 2; And a second step of transesterifying the aromatic carbonate obtained above with an aromatic dihydroxy compound to produce a polycarbonate.

1 is a process for producing a polycarbonate according to one embodiment of the present invention. As shown, the aromatic hydroxy compound is introduced along the line (1), dialkyl carbonate is introduced into the reactor (10) along the line (2), the catalyst inlet (3) is formed on one side of the reactor (10) . The aromatic carbonate produced in reactor 10 is introduced into reactor 20 along line 4, where aromatic dihydroxy compound may be introduced via line 6. In addition, a catalyst inlet 7 may be formed in the reactor 20 as necessary. The polycarbonate polymerized in the reactor 20 is discharged along the line 8. Although the drawing shows that the first and second steps are performed in separate reactors, it may be performed in a single reactor.

In an embodiment, the aromatic carbonate prepared in the first step may be recycled to the reactor 10 through the line 5 to increase the yield of the diaryl carbonate.

The aromatic dihydroxy compound may be represented by the following formula (5).

[Chemical Formula 5]

(Wherein, A is a cycloalkylidene, -S- or -SO ₂ of a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ of the - denotes a).

Specific examples of the aromatic dihydroxy compound of Formula 5 include 4,4'-dihydroxydiphenyl, 2,2-bis- (4-hydroxyphenyl) -propane, 2,4-bis- Phenyl) -2-methylbutane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, 2,2- - (3,5-dichloro-4-hydroxyphenyl) -propane, and the like, but are not limited thereto. Of these, 2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro- Hydroxyphenyl) -cyclohexane, and the like, and 2,2-bis- (4-hydroxyphenyl) -propane, also referred to as bisphenol-A, is most preferred.

In an embodiment the second step can be carried out in the presence of a catalyst consisting of alkali, alkaline earth metal or mixtures thereof.

In an embodiment of the present invention, the second step may be performed under reduced pressure at 150 to 300 ° C, preferably 160 to 280 ° C, more preferably 190 to 260 ° C. And is preferable in reducing the reaction rate and the side reaction in the above temperature range.

In addition, the second step is at least 10 minutes, preferably 15 minutes to 24 hours, more preferably 15 minutes to 75 torr or less, preferably 30 torr or less, more preferably 1 torr or less under reduced pressure conditions. Running for 12 hours is preferred for reducing reaction rate and side reactions.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Example

Example 1

In a 200 ml autoclave reactor with external heater, phenol (65.88 g, 700 mmol), dimethyl carbonate (31.53 g, 350 mmol), Sm (acac) ₃ x H ₂ O (0.0098 g, 0.022 mmol) as catalyst And replace the oxygen in the reactor with nitrogen. Then, after raising the temperature of the reactor to 230 ℃ and maintained for 15 minutes, using a cooler to reduce the yield and conversion by using gas chromatography.

Example 2

The reaction was carried out in the same manner as in Example 1 except that the mixture was maintained at 230 ° C. for 30 minutes.

Example 3

The reaction was carried out in the same manner as in Example 1 except that the mixture was maintained at 230 ° C. for 60 minutes.

Example 4

The reaction was carried out in the same manner as in Example 1, except that a cylinder filled with 40 g of a molecular sieve (4 mm 3) was mounted and maintained at 230 ° C. for 30 minutes.

Example 5

The reaction was carried out in the same manner as in Example 4 except that the mixture was maintained at 230 ° C. for 60 minutes.

Example 6

The reaction was carried out in the same manner as in Example 4 except that the mixture was maintained at 230 ° C. for 120 minutes.

Example 7

The reaction was carried out in the same manner as in Example 1 except that phenol (32.94 g, 350 mmol) was used.

Comparative Example 1

The reaction was carried out in the same manner as in Example 1, except that n- Bu ₂ SnO was used as the catalyst.

Comparative Example 2

The reaction proceeded in the same manner as in Comparative Example 1 except that the mixture was maintained at 230 ° C. for 30 minutes.

Comparative Example 3

The reaction was carried out in the same manner as in Example 1, except that n- Bu ₂ Sn (OAc) ₂ was used as the catalyst.

Comparative Example 4

The reaction was carried out in the same manner as in Comparative Example 3 except that the reaction temperature reached 230 ° C. and maintained for 30 minutes.

Comparative Example 5

The reaction was carried out in the same manner as in Example 1 except that Zr (OBu) ₄ was used as a catalyst.

Comparative Example 6

The reaction proceeded in the same manner as in Comparative Example 5 except that the mixture was maintained at 230 ° C. for 30 minutes.

Comparative Example 7.

The reaction was carried out in the same manner as in Example 6 except that PbO was used as the catalyst.

Comparative Example 8.

The reaction was carried out in the same manner as in Example 1 except that Sm ₂ O ₃ was used as the catalyst.

catalyst Molecular sieve Reaction temperature
( ^o C) Reaction time (min) MPC yield ^{1 )} (%) DMC conversion ^{2 )} (%) room
city
Yes One Sm (acac) ₃ x H ₂ O No filling 230 15 6.54 7.00 2 Sm (acac) ₃ x H ₂ O No filling 230 30 6.78 7.73 3 Sm (acac) ₃ x H ₂ O No filling 230 60 5.78 8.08 4 Sm (acac) ₃ x H ₂ O Filling 230 30 8.84 9.88 5 Sm (acac) ₃ x H ₂ O Filling 230 60 14.18 16.95 6 Sm (acac) ₃ x H ₂ O Filling 230 120 20.21 24.89 7 Sm (acac) ₃ x H ₂ O No filling 230 15 5.06 5.65 Comparative Example One n -Bu ₂ SnO No filling 230 15 3.38 3.48 2 n -Bu ₂ SnO No filling 230 30 5.58 5.70 3 n- Bu ₂ Sn (OAc) ₂ No filling 230 15 2.37 2.46 4 n- Bu ₂ Sn (OAc) ₂ No filling 230 30 4.67 4.78 5 Zr (OBu) ₄ No filling 230 15 2.26 2.37 6 Zr (OBu) ₄ No filling 230 30 4.40 4.59 7 PbO Filling 230 120 9.82 11.72 8 Sm ₂ O ₃ No filling 230 15 0.35 0.40

1) MPC yield = number of moles of produced methylphenyl carbonate (MPC) / number of moles of dimethyl carbonate (DMC) used as reactants × 100

2) DMC conversion = (moles of produced methylphenylcarbonate (MPC) + moles of diphenylcarbonate + moles of anisole) / moles of dimethyl carbonate (DMC) used as reactants × 100

As shown in Table 1, it can be confirmed that Example 1-7 has an excellent conversion rate at the same temperature and time compared to Comparative Examples 1-8.

Preparation of Polycarbonate

Example 8

196 Kg (906 mol) of aromatic carbonate prepared in Example 1, 180 Kg (788 mol) of 2,2-bis (4-hydroxyphenyl) propane and 120 ppb of KOH (relative to 1 mol of BPA) were sequentially added to the reactor. Nitrogen was then used to remove oxygen in the reactor. The temperature of the reactor was raised to 160 ° C to dissolve the raw material, and then the temperature was raised to 190 ° C and maintained for 6 hours. After 6 hours, the reactor was heated up to 220 degrees, and the pressure was maintained at 70 Torr for 1 hour. The polycarbonate was synthesized by maintaining the temperature at 260 ° C. for 1 hour at 20 torr and then lowering the pressure to 0.5 torr for 1 hour. The molecular weight of the prepared polycarbonate was Mw 22.0 K.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

1 ~ 8: line
10, 20: reactor

Claims (8)

A method for producing an aromatic carbonate from a dialkyl carbonate, comprising reacting an aromatic hydroxy compound with a dialkyl carbonate in the presence of a samarium-based catalyst represented by the following formula (2):

(2)

(In the above, R1 and R2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms)

The method of claim 1, wherein the catalyst is used in an amount of 1 × 10 ⁻⁵ to 5 × 10 ⁻¹ moles with respect to 1 mole of dialkyl carbonate.
The method of claim 1, wherein the reaction is carried out at a temperature of 100 to 280 ℃.
The method of claim 1 wherein the reaction is carried out in a reactor filled with molecular sieves.
The method of claim 1, wherein the aromatic hydroxy compound is represented by the following Chemical Formula 3:

(3)
Ar-OH
(Wherein Ar is a substituted or unsubstituted aryl group).
The method of claim 1, wherein the dialkyl carbonate is represented by the following formula (4):

[Chemical Formula 4]

(Wherein R ₁ and R ₂ are each an alkyl group having 1 to 6 carbon atoms and are the same or different from each other).
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