TWI433837B - Aromatic carbonate, method of preparing the same, and polycarbonate prepared using the same - Google Patents

Description

Aromatic carbonate, preparation method thereof and polycarbonate prepared therefrom

This invention relates to aromatic carbonates, to processes for their preparation, and to polycarbonates prepared therewith. More specifically, the present invention relates to an aromatic carbonate prepared by using a catalyst and a polycarbonate prepared using such an aromatic carbonate.

Aromatic carbonates are monomers suitable for the preparation of polycarbonates, and extensive research has been conducted on the development of their preparation methods. Aromatic carbonates have traditionally been prepared by phosgenation of phenol and phosgene in the presence of a base. However, this method involves the problem that the use of toxic phosgene and the neutral salt produced as a by-product must be treated.

In order to solve this disadvantage, the production of aromatic carbonates by transesterification of phenols with aliphatic carbonates such as dimethyl carbonate has been carried out. The transesterification is generally carried out in the presence of a catalyst such as PbO, TiX ₄ (X = alkoxy or aryloxy), SnR ₂ (OPh) ₂ (R = alkyl) or the like. PbO is highly stable but has low catalytic activity, resulting in significantly lower reaction rates. TiX ₄ and SnR ₂ (OPh) ₂ have higher activity than PbO, but are insufficiently stable and produce a large amount of ether as a by-product.

Further, a method of producing an aromatic carbonate by carrying out a carbonylation reaction of an aromatic hydroxy compound using carbon monoxide and oxygen is being developed. However, since such a synthesis method using carbon monoxide as a reactant has a relatively low reactivity and requires a high pressure reactor, it is not suitable for commercialization.

Therefore, there is still a need for a process for producing an aromatic carbonate stably and in high yield using a dialkyl carbonate instead of carbon monoxide as a raw material.

One aspect of the present invention provides a process for producing an aromatic carbonate in high yield using a dialkyl carbonate instead of carbon monoxide as a raw material. This method accelerates the esterification rate of dialkyl carbonate compared to the conventional catalytic system to exhibit high catalytic activity, thereby efficiently producing a diaryl carbonate.

Another aspect of the invention provides a polycarbonate using the diaryl carbonate prepared by the above process.

According to another aspect of the invention, there is provided a process for the preparation of an aromatic carbonate from a dialkyl carbonate. The method comprises reacting an aromatic hydroxy compound and a dialkyl carbonate in the presence of at least one type of ruthenium-containing catalyst represented by the following formula 1 or 2.

[Formula 1]

SmX ₃

Wherein X is a C1 to C10 alkoxy group, a C1 to C10 alkylphenoxy group or a phenoxy group.

Wherein R1 and R2 are independently hydrogen and C1 to C6 alkyl, respectively.

This catalyst can be used in an amount of from 1 × 10 ^-5 to 5 × 10 ^-1 mol based on 1 mol of the dialkyl carbonate.

The reaction can be carried out at 100 to 280 °C.

The reaction can be carried out in a reactor packed with molecular sieves.

The aromatic hydroxy compound can be represented by Formula 3:

[Formula 3]

Ar-OH

Wherein Ar is a substituted or unsubstituted aryl group.

This dialkyl carbonate can be represented by Formula 4:

Wherein R1 and R2 are each a C1 to C6 alkyl group, and are the same or different.

According to another aspect of the present invention, an aromatic carbonate synthesized by the above method is provided. The aromatic carbonate is synthesized using at least one type of ruthenium-containing catalyst represented by Formula 1 or 2.

According to another aspect of the present invention, a polycarbonate resin obtained by polymerization of an aromatic carbonate is provided.

The above and other aspects, features, and advantages of the present invention will be apparent from the description and appended claims.

Embodiments of the present invention will now be described in detail with reference to the drawings.

The method for producing an aromatic carbonate from a dialkyl carbonate according to an exemplary embodiment of the present invention includes an aromatic hydroxy compound and a dialkyl carbonate in the presence of at least one type of ruthenium-containing catalyst represented by the following formula 1 or 2 Carry out the reaction.

[Formula 1]

SmX ₃

Wherein X is a C1 to C10 alkoxy group, a C1 to C10 alkylphenoxy group or a phenoxy group.

Wherein R1 and R2 are independently hydrogen and C1 to C6 alkyl, respectively.

In one embodiment, X may be at least one selected from the group consisting of: methoxy, ethoxy, isopropoxy, butoxy, phenoxy, 2,6-di Tert-butyl-4-methylphenoxy, and combinations thereof. Further, such a catalyst represented by Formula 1 or 2 can be used as a mixture.

In one embodiment, such a catalyst may be used in an amount of from 1 × 10 ^-5 to 5 × 10 ^-1 mol, preferably from 5 × 10 ^-5 to 5 × 10 ^-2 mol, based on 1 mol of the dialkyl carbonate. Within this range, the catalyst can have excellent performance and can be easily recovered.

The aromatic hydroxy compound can be represented by Formula 3:

[Formula 3]

Ar-OH,

Wherein Ar is a substituted or unsubstituted aryl group.

Ar may be a phenyl or naphthyl group, and such a substituted group may be a C1 to C4 alkyl group, a halogen, an alkoxy group, a nitro group or a cyano group.

Examples of the aromatic hydroxy compound may include, but are not limited to, phenol, naphthol, cresol, chlorophenol, alkylphenol, nitrophenol, cyanophenol, and the like. Phenol is preferably used as the aromatic hydroxy compound.

The dialkyl carbonate can be represented by the formula 4:

Wherein R1 and R2 are each a C1 to C6 alkyl group, and are the same or different.

Examples of the dialkyl carbonate may include, but are not limited to, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, ethyl methyl carbonate, methylpropyl carbonate, and ethylene propyl carbonate. Preferably, dimethyl carbonate can be used.

In one embodiment, the reaction can be carried out at from 100 ° C to 280 ° C, preferably from 120 ° C to 250 ° C, and more preferably from 180 ° C to 240 ° C. Within this range, the diaryl carbonate can be produced in high yield.

Transesterification can be carried out at 760 mmHg to 15,000 mmHg, preferably 760 mmHg to 7,500 mmHg.

The reaction can generally be carried out for from 1 s to 150 min, which is not limited.

The aromatic carbonate prepared by the above method can be used for the polymerization of polycarbonate. Examples of such an aromatic carbonate may include, but are not limited to, diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, di(biphenyl) carbonate. Etc., it can be used alone or as a mixture thereof. Specifically, diphenyl carbonate can be used.

In one embodiment, the aromatic carbonate obtained by the foregoing method may be transesterified with an aromatic dihydroxy compound, thereby producing a polycarbonate.

For example, in the first step, the aromatic hydroxy compound and the dialkyl carbonate may be reacted in the presence of at least one ruthenium-containing catalyst represented by the following formula 1 or 2 to prepare an aromatic carbonate. Subsequently, in the second step, the aromatic carbonate obtained by the first step is transesterified with an aromatic dihydroxy compound to prepare a polycarbonate.

FIG. 1 illustrates a method of preparing a polycarbonate according to an exemplary embodiment. As shown in Figure 1, an aromatic hydroxy compound and a dialkyl carbonate can be introduced into the reactor 10 via line 1 and line 2, respectively. The reactor 10 may have a catalyst inlet 3 formed on one side thereof. The aromatic carbonate produced in the reactor 10 can be introduced into the reactor 20 via line 4, and the aromatic hydroxy compound can be introduced into the reactor 20 via line 6. Reactor 20 can include catalyst inlet 7 as desired. The polycarbonate synthesized in the reactor 20 can be discharged by the line 8. Figure 1 illustrates the first and second steps carried out in a separate reactor, but these two steps can be carried out in the same reactor.

In one embodiment, the aromatic carbonate prepared in the first step can be recycled to the reactor 10 by line 5, thereby improving the yield of the diaryl carbonate.

This aromatic dihydroxy compound can be represented by Formula 5:

Wherein A represents a single bond, C1 to C5 alkylene group (alkylene), C1 to C5 alkylene (alkylidene), C5 to C6 cycloalkylene, -S- or SO _2.

Examples of such an aromatic dihydroxy compound represented by Formula 5 may include 4,4'-dihydroxybiphenyl, 2,2-di-(4-hydroxyphenyl)-propane, 2,4-di-(4) -hydroxyphenyl)-2-methylbutane, 1,1-di-(4-hydroxyphenyl)-cyclohexane, 2,2-di-(3-chloro-4-hydroxyphenyl)-2 - propane, 2,2-di-(3,5-dichloro-4-hydroxyphenyl)-propane, etc., without limitation. Specifically, 2,2-di-(4-hydroxyphenyl)-propane, 2,2-di-(3,5-dichloro-4-hydroxyphenyl)-propane and 1,1- can be preferably used. Di-(4-hydroxyphenyl)-cyclohexane, and 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A) can be more preferably used.

In one embodiment, the second step can be accomplished in the presence of a catalyst comprising an alkali metal, an alkaline earth metal, or a mixture thereof.

In one embodiment, the second step can be carried out under reduced pressure at 150 ° C to 300 ° C, preferably 160 ° C to 280 ° C, and more preferably 190 ° C to 260 ° C. Within this temperature range, the reaction can be carried out at a suitable reaction rate and the side reaction can be appropriately reduced.

Further, depending on the reaction rate and the decrease in the side reaction, the second step can be carried out under a reduced pressure of 75 torr or less, preferably 30 torr or less, more preferably 1 torr or less, for at least 10 minutes. Preferably, it is from 15 min to 24 h, and more preferably from 15 min to 12 h.

Hereinafter, the constitution and function of the present invention will be explained in more detail with reference to the embodiments. The examples are provided for illustrative purposes only and are not to be construed as limiting the invention.

Embodiments not included herein will be readily appreciated and understood by those skilled in the art, and their explanation will be omitted herein.

Example

Example 1

Phenol (65.88 g, 700 mmol), dimethyl carbonate (31.53 g, 350 mmol) and Sm(acac) ₃ ‧xH ₂ O (0.0098 g, 0.022 mmol) as a catalyst were placed inside the external heater In a 200 mL autoclave reactor, a nitrogen atmosphere was introduced. Subsequently, the reactor was heated to 230 ° C for 15 min, and then cooled by a cooling unit, after which the yield and conversion were calculated by gas chromatography.

Example 2

The same procedure as in Example 1 was carried out except that the reactor heated to 230 ° C was kept for 30 minutes.

Example 3

The same procedure as in Example 1 was carried out except that the reactor heated to 230 ° C was maintained for 60 min.

Example 4

In addition to the installation filled with 40g molecular sieve (4 The cylinder was carried out in the same manner as in Example 1 except that the reactor heated to 230 ° C was kept for 30 minutes.

Example 5

The same procedure as in Example 4 was carried out except that the reactor heated to 230 ° C was maintained for 60 min.

Example 6

The same procedure as in Example 4 was carried out except that the reactor heated to 230 ° C was maintained for 120 min.

Example 7

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

Comparative example 1

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

Comparative example 2

The same procedure as in Comparative Example 1 was carried out except that the reactor heated to 230 ° C was kept for 30 minutes.

Comparative example 3

The same procedure as in Example 1 was carried out except that n- Bu ₂ Sn(OAc) _{2 was} used as the catalyst.

Comparative example 4

The same procedure as in Comparative Example 3 was carried out except that the reactor heated to 230 ° C was kept for 30 minutes.

Comparative Example 5

The same procedure as in Example 1 was carried out except that Zr(OBu) _{4 was} used as the catalyst.

Comparative Example 6

The same procedure as in Comparative Example 5 was carried out except that the reactor heated to 230 ° C was kept for 30 minutes.

Comparative Example 7

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

Comparative Example 8

The same procedure as in Example 1 was carried out except that Sm ₂ O _{3 was} used as the catalyst.

1) MPC yield = mole number of methyl phenyl carbonate (MPC) formed / mole number of dimethyl carbonate (DMC) used as a reactant × 100

2) DMC conversion = (molar number of generated MPC / mole number of diphenyl carbonate + mole number of anisole) / molar number of DMC used as a reactant × 100

As can be seen from Table 1, the products of Examples 1 to 7 had conversions exceeding the conversion of the products of Comparative Examples 1 to 8 at the same reaction temperature and time.

Preparation of polycarbonate

Example 8

196 kg (906 mol) of the aromatic carbonate prepared in Example 1, 180 kg (788 mol) of 2,2-bis(4-hydroxyphenyl)propane and 120 ppb (based on 1 mol of BPA) of KOH were sequentially added. The reactor was added, followed by a nitrogen atmosphere. The reactor was heated to 160 ° C to melt the reaction, followed by heating to 190 ° C for 6 h. After 6 hours, the reactor was heated to 220 ° C and then held at 70 Torr for 1 h. The reactor was heated to 260 ° C and held at 20 Torr for 1 h, then reduced to 0.5 Torr for 1 h, thereby synthesizing polycarbonate. The polycarbonate produced had a molecular weight (Mw) of 22.0 K.

Although some embodiments have been disclosed herein, it is to be understood that the invention is not limited by the appended claims The spirit and scope of the invention.

1‧‧‧pipe

2‧‧‧pipe

3‧‧‧ Catalyst imports

4‧‧‧pipe

5‧‧‧pipe

6‧‧‧pipe

7‧‧‧ Catalyst import

8‧‧‧pipe

10‧‧‧Reactor

20‧‧‧Reactor

FIG. 1 illustrates a method of producing polycarbonate according to an exemplary embodiment of the present invention.

1. . . Pipeline

2. . . Pipeline

3. . . Catalyst import

4. . . Pipeline

5. . . Pipeline

6. . . Pipeline

7. . . Catalyst import

8. . . Pipeline

10. . . reactor

20. . . reactor

Claims (6)

A process for producing an aromatic carbonate from a dialkyl carbonate, comprising: reacting an aromatic hydroxy compound and a dialkyl carbonate in the presence of at least one type of ruthenium-containing catalyst represented by Formula 2, Wherein R1 and R2 are independently hydrogen and C1 to C6 alkyl, respectively. The method of claim 1, wherein the catalyst is used in an amount of from 1 × 10 ^-5 to 5 × 10 ^-1 mol based on 1 mol of the dialkyl carbonate. The method of claim 1, wherein the reaction is carried out at a temperature of from 100 to 280 °C. The method of claim 1, wherein the reaction is carried out in a reactor packed with molecular sieves. The method of claim 1, wherein the aromatic hydroxy compound is represented by Formula 3: [Formula 3] Ar-OH Wherein Ar is a substituted phenyl or naphthyl group or an unsubstituted phenyl or naphthyl group, and the substituted group in the substituted phenyl or naphthyl group is a C1 to C4 alkyl group, a halogen, an alkoxy group, a nitrate Base or cyano group. The method of claim 1, wherein the dialkyl carbonate is represented by Formula 4: Wherein R1 and R2 are each a C1 to C6 alkyl group, which are the same or different.