JPH04136031A - Preparation of polycarbonate - Google Patents

Abstract

PURPOSE:To prepare an alkyl-terminated polycarbonate economically at a high yield by reacting a specific polyol, a monoalcohol, and a polycarbonate compd. CONSTITUTION:A polyol shown by R1(OH)l (wherein R1 is a 4-300C aliph. hydrocarbon group, a 4-300C aliph. hydrocarbon group contg. ether bonds, or a 6-300C cyclic hydrocarbon group contg. ether bonds; and l is an integer of 2-8), a monoalcohol shown by R2OH (wherein R2 is a 30C or lower hydrocarbon group or a 2-30C hydrocarbon group contg. ether bonds), and a polycarbonate compd. shown by R3OCOOR3 (wherein each R3 is independently 1-2C alkyl), the b.p. of R3OH being lower than the boiling points of the polyol and the monoalcohol, in such an amt. of the polycarbonate compd. that the molar ratio of it to ltimes the molar number of the polyol (lm1) is 2-50 are thermally reacted in the presence of a basic catalyst while removing the resulting alcohol (R3OH) from the reaction system by distillation to a conversion of 95% or hither. Then, the catalyst is removed and an unreacted polycarbonate compd. [shown by R4OCOOR4 (wherein R4 is R2 or R3)] is removed by distillation, giving a polycarbonate shown by R1(OCOO-R2)l (wherein R1, l, and R2 are as difined above).

Description

[Detailed description of the invention] Technical field of invention The present invention relates to a method for producing polycarbonate.

TECHNICAL BACKGROUND OF THE INVENTION Polycarbonates are useful as a variety of lubricating oils or components thereof.

Among polycarbonates, polycarbonates having an alkyl group at the end of the molecule have the advantage of low hygroscopicity. A method for manufacturing such polycarbonate is described in Japanese Patent Application Laid-open No. 46-3865 and the like. That is, JP-A-46-3865 discloses that in a mixture of n moles of diol and (n-1) moles of diphenyl carbonate, 1 or 2 moles of diol are replaced with 1 or 2 moles of monoalcohol. It is described how polycarbonate can be obtained by. For example, the above-mentioned Bungaku describes a method for producing polycarbonate having a decyl group at the molecular terminal by using n-decanol as the monoalcohol and polyethylene glycol as the diol, heating under reduced pressure, and reacting. .

In the above method, highly reactive diphenyl carbonate is preferably used as the raw material carbonate. Furthermore, diphenyl carbonate has a high boiling point,
It is preferably used because it is easy to set reaction conditions.

On the other hand, with dimethyl carbonate and diethyl carbonate, which have low reactivity and a low boiling point, it is not easy to make the molecular terminal substantially only an alkyl group by the above method. Furthermore, when these carbonates with low reactivity are used as raw materials, it is necessary to use a catalyst, but it is also not easy to remove the high-boiling point catalyst from the reaction product.

However, it is industrially and economically advantageous to use dimethyl carbonate or diethyl carbonate, which are cheaper than diphenyl carbonate, as raw materials.

Furthermore, it is generally known that polycarbonate can be obtained by reacting a monoalcohol with a carbonate compound such as dimethyl carbonate.

However, according to the conventional method in which a polyol is reacted with a carbonate compound instead of a monoalcohol, and after the reaction is completed, the unreacted carbonate compound is distilled off by heating, and the catalyst is neutralized with an acid. Polymerization occurs during the step of distilling off the carbonate compound, making it impossible to obtain the desired polycarbonate in good yield.

By the way, although it is not a prior art, the applicant has
Patent application filed on April 27, 2012.21
In Specification No. 2, (a) General formula (I) R' (OH)□ (wherein, R1 represents an aliphatic hydrocarbon group having 4 to 300 carbon atoms, and may contain an ether bond. m is 2~
Indicates an integer of 8. ) and fb) a carbonate compound represented by general formula (II) R20COOR2 (wherein R2 represents an alkyl group having 1 to 20 carbon atoms) in the presence of a base catalyst, The produced alcohol is removed from the reaction system by distillation to allow the reaction to reach a reaction rate of 95% or more, and then, after the base catalyst is removed, the unreacted carbonate compound is removed from the reaction system by distillation. Characterized by the general formula (I[[)% formula%) (wherein RI R2 and m are the same as above).

) proposes a method for producing a polycarbonate compound represented by: Among the polycarbonates represented by the above general formula (m), when producing a polycarbonate in which R2 is an alkyl group having 3 to 20 carbon atoms, the general formula (
In n), a carbonate compound in which R2 is an alkyl group having 3 to 20 carbon atoms corresponding to the above alkyl group is used. However, since these carbonate compounds are difficult to obtain, they must be synthesized in advance when producing the above polycarbonate.

In addition, in the specification of Japanese Patent Application No. 112.211 filed on April 27, 1990, the applicant of the present application stated that (
a) General formula (T) HO-R' -0H (in the formula, R1 is CC, , R2,0), C,, R2゜ (in the formula, m represents an integer of 1 to 10, a is (indicates an integer from 1 to 100) indicates a polyalkylene glycol residue represented by: ) (b) general formula (II) 20H (wherein R2 is an alkyl group or aryl group having 2 to 20 carbon atoms or a general formula % formula %) (wherein R3 is , represents an alkyl group or aryl group having 1 to 20 carbon atoms, n represents an integer of 1 to 10, and b represents an integer of 1 to 100. ) In the presence or absence of a monoalcohol represented by While heating under normal pressure or increased pressure in the presence of alcohol, the generated alcohol represented by the general formula is removed from the reaction system by distillation to react to a reaction rate of 95% or more, and then the unreacted carbonate compound is removed from the reaction system. (I [I) is removed from the reaction system by distillation, then heated under reduced pressure to perform condensation polymerization, and the base catalyst in the resulting reaction product is neutralized with acid. General formula % Formula % (wherein, R1 is the same as above, R5 and R6 each independently represent R2, R4, or a mixture of R2 and R4, and the average X is 0 .5 to 10 is shown.

) We have proposed a method for producing polyalkylene glycol polycarbonate represented by: This manufacturing method is similar to the method for manufacturing polycarbonate according to the present invention described later, but unlike the present invention, condensation polymerization is performed in the second reaction step, so the product is a polycarbonate with a wide molecular weight distribution. is obtained.

Purpose of the Invention The present invention aims to solve the problems associated with the prior art as described above, and provides a method for economically producing polycarbonate having an alkyl group at the end of the molecule in high yield. is intended to provide.

Summary of the Invention The method for producing polycarbonate according to the present invention is based on the general formula %) [wherein R7 and l are the same as R + and l in the following general formula [I], and R2 is the following A method for producing a polycarbonate represented by the same formula as R2 in the general formula [I], (a) General formula [I] R+(oH)z ... [I] [Formula [I]
In the formula, R1 is an aliphatic hydrocarbon group having 4 to 300 carbon atoms, an aliphatic hydrocarbon group having ether bond having 4 to 300 carbon atoms, or a cyclic structure having ether bond having 6 to 300 carbon atoms. a hydrocarbon group, l is an integer of 2 to 8], (b) general formula [I [] R, OH... [II] [In formula [II], R2 is a carbon atom A monoalcohol represented by a hydrocarbon group having a number of 30 or less or a hydrocarbon group having an ether bond having 2 to 30 carbon atoms], and (cl General formula [■] R,0COOR,... [m] [ In formula [I11], R6 is each independently an alkyl group having 1 to 2 carbon atoms], and R3
The boiling point of 0H is lower than the boiling point of the above polyol and monoalcohol, and the molar ratio to 1 times the number of moles (1 m+) of the polyol represented by the above general formula [I] is 2 to 50.
The amount of carbonate compound in the range of is heated in the presence of a basic catalyst, the alcohol (R,OH) produced is removed from the reaction system by distillation, and the reaction is allowed to reach a reaction rate of 95% or more, and then , after removing the base catalyst, the carbonate compound [R40CO2R4 (wherein R4 is
R2 to R3)] are removed from the reaction system by distillation.

DETAILED DESCRIPTION OF THE INVENTION The method for producing polycarbonate according to the present invention will be specifically described below.

In the present invention, certain polyols, certain monoalcohols, and certain carbonate compounds are used.

The polyol used in the present invention has the following general formula [I]
It is expressed as

R+(OH)* ...[I] In the above general formula [I], R1 is an aliphatic hydrocarbon group having 4 to 300 carbon atoms, or an aliphatic carbonized group having ether bond having 4 to 300 carbon atoms. Hydrogen group or 6 to 3 carbon atoms
It is a hydrocarbon group with a cyclic structure having 00 ether bonds, and l is an integer of 2 to 8.

Specifically, the polyol represented by the above general formula [I] includes glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol; ethylene oxide and propylene oxide. Diols copolymerized with pentaerythritol, dipentaerythritol, trimethylolpropane, neopentyl glycol, hexylene glycol: pentaerythritol, dipentaerythritol, trimethylolpropane, neopentyl glycol or hexylene glycol and ethylene oxide or propylene oxide. polyols consisting of reaction products of propylene oxide or ethylene oxide and hydroxymethylethylene oxide or glycerin; pyranoses such as glucobylanose, galactopyranose, mannopyranose; fructofuranose, ribofuranose, etc. Furanose and the like are preferably used, but nbutylene glycol, tributylene glycol, polybutylene glycol and the like can also be used.

The monoalcohol used in the present invention has the following general formula [
I1].

R20H...[II'1 In the above general formula [I1], R2 has 3 carbon atoms
It is a hydrocarbon group having 0 or less hydrocarbon groups or a hydrocarbon group having 2 to 30 carbon atoms and having an ether bond.

Examples of the hydrocarbon group R2 below include an aliphatic hydrocarbon group, a ring hydrocarbon group, an aromatic hydrocarbon group, an aromatic aliphatic hydrocarbon group, and the general formula % formula % (wherein, R5 is the number of carbon atoms is an alkylene group of 2 to 3, R6 is a hydrocarbon group having 28 or less carbon atoms, and q
is an integer of 1 to 20).

Specific examples of the aliphatic hydrocarbon group for R2 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, S-butyl group, l-
Butyl group, pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, isoheptyl group, n-octyl group, isooctyl group,
n-nonyl group, isononyl group, n-decyl group, isodecyl group, n-undecyl group, isoundecyl group, n-dodenyl group, isododecyl group, n-tridecyl group, isotridecyl group, n-tetradecyl group, isotetradecyl group, n
-pentadecyl group, isopentadecyl group, n-hexadecyl group, isohexadecyl group, n-heptadecyl group, isoheptadecyl group, n-octadecyl group, isooctadecyl group, n-nonyldecyl group, isononyldecyl group, n
Examples include -icosanyl group, isoicosanyl group, 2-ethylhexyl group, and 2-(4-methylpentyl) group.

Further, specific examples of the alicyclic hydrocarbon group in R2 include a cyclohexyl group, 1-cyclohexenyl group, methylcyclohexyl group, dimethylcyclohexyl group, decahydronaphthyl group, tricyclodecanyl group, etc. I can do it.

Further, specific examples of the aromatic hydrocarbon group for R2 include phenyl group, o-tolyl group, p-tolyl group, tutolyl group, 2,4-xylyl group, mesityl group, l-naphthyl group, etc. I can do it.

Furthermore, specific examples of the aromatic aliphatic hydrocarbon group for R2 include Hensyl group, methylbenzyl group, β-
Examples include phenylethyl group (phenethyl group), 1-phenylethyl group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, styryl group, and cinnamyl group.

Specific examples of the alkyushin group in R5 above are:
Examples include ethylene group, propylene group, and isopropylene group.

Further, examples of the hydrocarbon group in R, , above include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Specific examples of these include the same groups as those listed as specific examples of the aliphatic hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group for R2, respectively. .

Specifically, the glycol ether group represented by the above general formula includes ethylene glycol monomethyl ether group, diethylene glycol mono-n-butyl ether group, triethylene glycol monoethyl ether group, propylene glycol monomethyl ether group, dipropylene glycol monoethyl Examples include ether group, tripropylene glycol monobutyl ether group, and the like.

In the case of lubricating oil for refrigerators that uses ozone layer non-depleting fluorocarbon gas such as Freon R134a as a refrigerant, R2 is a lower alkyl group such as a methyl group, an ethyl group, an isopropyl group, or an n-butyl group, or an ethylene glycol monomethyl group. Preferred are alkylene glycol monoalkyl ether groups such as ether group, diethylene glycol monomethyl ether group, triethylene glycol monomethyl ether group, propylene glycol monomethyl ether group, dipropylene glycol monoethyl ether group, and tripropylene glycol mono-n-butyl ether group.

The carbonate compound used in the present invention is represented by the following general formula [I11].

R,0COOR3 [■] In the above general formula [II], R3 each independently represents an alkyl group having 1 to 2 carbon atoms.

Specific examples of the carbonate compound represented by the general formula [I11] include dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate.

These carbonate compounds are easily available.

The method for producing polycarbonate according to the present invention is a method for producing polycarbonate represented by the following general formula [■] using the above-described polyol, monoalcohol, and carbonate compound.

R+ (OCOOR2) s...[I
V] In the above general formula [IV], R7 and l are
Same as R, , i in general formula [II, and R
2 is the same as R2 in general formula [I1].

First, (a) a polyol represented by the general formula [II R, (OH), ... [I], (h) a monoalcohol represented by the general formula [II] R20H [■], and (c) a general formula [] R30COOR, ... [I[[] and the boiling point of R30H is lower than the boiling point of the above polyol and monoalcohol,
] is heated in the presence of a base catalyst in an amount such that the molar ratio of the carbonate compound to 1 times the number of moles (1 ml) of the polyol is in the range of 2 to 50, and then the resulting alcohol (R,OH) is heated. It is removed from the reaction system by distillation and allowed to react to a reaction rate of 95% or more.

1 in the above 1m represents the number of hydroxyl groups in the polyol.

In carrying out the above reaction, it may be desirable to replace the air in the reactor with nitrogen, or it may not be necessary to replace the air with nitrogen.

Next, after removing the base catalyst, unreacted carbonate compounds [R40C
O2R4 (in the formula, R4 is each independently R2 or R3) is removed from the reaction system by distillation to obtain a polycarbonate represented by the above general formula [IV].

In this method, the alcohol produced in the carbonation reaction is removed from the reaction system by distillation while the carbonation reaction proceeds, so the alcohol produced in this reaction,
That is, the alcohol represented by R, OH needs to have a lower boiling point than the polyol and monoalcohol.

Further, the carbonate compound is used in an amount such that the molar ratio to 1 times the number of moles (l m + ) of the polyol represented by the above general formula [I] is in the range of 2 to 50. By limiting the amount of the carbonate compound used in this way, it is possible to suppress the production of polycarbonate with a high degree of polymerization.

In this method, the reaction is carried out by charging the above-mentioned polyol, monoalcohol, and carbonate compound into a reaction vessel, heating it in the presence of a base catalyst, and removing the generated alcohol from the reaction system by distillation. rate 95
% or more, and then, after removing the base catalyst, the unreacted carbonate compound [R40CO2RJ (in the formula, R4 is each independently R2 to R3)] that does not reach the final stage reaction is distilled. It is removed from the reaction system by A reaction rate of 95% or more means that the reaction is performed until 0.95 times the number of moles of the alcohol produced above is produced.

The above-mentioned base catalysts include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates and hydrogen carbonates such as sodium carbonate and sodium hydrogen carbonate,
Alkali metal alcoholades such as sodium methoxide, potassium methoxide, lithium methoxide, and cesium methoxide, and alkali metal compounds such as sodium hydride and sodium amide are preferably used. Among these, alkali metal alcoholades are particularly preferred. In addition, for example, alkaline earth metal compounds such as magnesium hydroxide and calcium hydroxide, trimethylamine,
Organic amino compounds such as triethylamine, imidazole, and tetramethylammonium hydroxide are also used. The amount of these catalysts used is usually the number of moles of catalyst/1
m (molar ratio) is 10-1 to 10, preferably 10-1
It is used within the range of 0-5.

In this method, the reaction is usually carried out at 50 to 300°C,
Preferably it is carried out at a temperature of 60 to 200°C. The reaction time is usually 0.5 to 200 hours, preferably 1 to 10 hours.
It is 0 hours.

After the reaction is completed, the catalyst is removed by washing with water or neutralizing with acid. Examples of acids include solid acids such as sulfonic acid type ion exchange resins; inorganic acids such as carbonic acid, ammonium carbonate, ammonium chloride, hydrochloric acid, sulfuric acid, and phosphoric acid; acetic acid,
Organic acids such as phenol are used. Among these, for example, sulfonic acid type ion exchange resins and weak inorganic acids such as ammonium carbonate are preferably used.

According to this method, after removing the base catalyst, the unreacted carbonate compound is removed by distillation under reduced pressure. Polymerization of the resulting polycarbonate can be prevented and the desired polycarbonate can be obtained in high yield.

The polycarbonate thus obtained may be treated with an adsorbent such as activated clay or activated carbon or washed with water to remove trace amounts of impurities, if necessary. In particular, according to such a treatment, trace amounts of ionic compounds and polar compounds can be removed, so that the obtained polycarbonate can be stably maintained.

According to the above method, when dimethyl carbonate is used as the carbonate compound in the above reaction, instead of removing methanol from the reaction system as an azeotrope with dimethyl carbonate, cyclohexane, hexane, hexane, etc. is added to the reaction system in advance. can be added as an azeotropic solvent, and methanol can be removed from the reaction system as an azeotrope with these azeotropic solvents. The azeotropic solvent is generally used in an amount of 5 to 100% by weight based on 100% by weight of dimethyl carbonate.

According to this method, in the reaction, methanol is removed from the reaction system as an azeotrope with the azeotropic solvent, and after the reaction is completed, unreacted dimethyl carbonate is recovered from the reaction mixture, so the recovery rate can be reduced. It can be improved.

Alternatively, as described above, methanol is recovered as an azeotrope with dimethyl carbonate, and then the above azeotropic solvent is added to this azeotrope, and methanol is recovered as an azeotrope with these azeotropes. Dimethyl carbonate can also be recovered by removing it from dimethyl carbonate.

Effects of the Invention According to the present invention, after the reaction between the polyol and the carbonate compound is completed, the base catalyst used is removed, and then the unreacted carbonate compound is removed, so that the desired polycarbonate can be obtained in high yield. I can do it.

Furthermore, in the present invention, since readily available dimethyl carbonate, dimethyl carbonate, or ethyl methyl carbonate is used as the carbonate compound, there is no need to synthesize these carbonate compounds in advance when producing polycarbonate.

Therefore, according to the present invention, the desired polycarbonate can be economically produced.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 192 g of tripropylene glycol (1,
00 mol), 2-ethylhexanol 1301 g (
9.99 mol), dimethyl carbonate 901 g (
10,01 mol) and 28% by weight of Na OCHs
A methanol solution (NaOCH 30,001 mol) was charged.

This mixture was heated at 96 to 175° C. for 12 hours under normal pressure, and the methanol produced was distilled off. The amount of methanol distilled out was 365 g (11.41 mol).

Next, the pressure inside the system was gradually reduced from 760 mmHg to 10
■■) Under the pressure of Ig, the reaction was carried out at 170 to 190°C for 5 hours, and 17 g of methanol, 139 g of dimethyl carbonate, 6 g of 2-ethylhexanol and methyl
44 g of 2-ethyl hequinle carbonate was distilled out.

The amount of methanol distilled out was 99.8% of the theoretical amount. 1600 g of the reaction mixture thus obtained (recovery rate 99
．． The catalyst was neutralized with an aqueous solution containing ammonium carbonate in an amount 5 times the molar amount of Na0CH used in the solution (7%), and further washed with water three times to separate the aqueous layer. Next, unreacted di[2-ethylhexyl]carbonate was distilled off from the oil layer under reduced pressure to obtain 446 g of a carbonate reaction product.

The yield of the carbonate reaction product obtained was 89%.

Kinematic viscosity of this product (100°C, JIS K-2283
> was 5.1 cSt. Further, the residual amount of sodium in the produced carbonate was 0.01 ppm or less, and the total acid value was 0.01 or less.

As a result of NMR analysis, it was confirmed that the main product was tripropylene glycol-di[2-ethylhexyl]carbonate.

Examples 2 to 3 Example 1 except that the amounts of tripropylene glycol, 2-ethylhexanol, dimethyl carbonate, and 28% by weight methanol solution of Na OCH3 were changed as shown in Table 1. The reaction was carried out in the same manner as above to obtain a carbonate reaction product.

The results are shown in Table 1.

Examples 4 to 10 The reaction was carried out in the same manner as in Example 1, except that the types and amounts of polyol [R1(OH),] and monoalcohol [R20H] were changed as shown in Table 1. A carbonate reaction product was obtained.

The results are shown in Table 1.

Claims (1)

[Claims] (1) (a) General formula [I] R_1(OH)_2... [I] [In formula [I], R_1 is an aliphatic hydrocarbon group having 4 to 300 carbon atoms, Aliphatic hydrocarbon group having an ether bond or having 6 to 30 carbon atoms
a hydrocarbon group with a cyclic structure having 0 ether bonds, l is an integer of 2 to 8], (b) General formula [II] R_2OH...[II] [In formula [II], R_2 is a hydrocarbon group having 30 or less carbon atoms or a hydrocarbon group having an ether bond having 2 to 30 carbon atoms], and (c) general formula [III] R_3OCOOR_3...[III] [In formula [III], R_3 is each independently an alkyl group having 1 to 2 carbon atoms], and R_
The boiling point of 3OH is lower than the boiling point of the above polyol and monoalcohol, and the molar ratio to 1 times the number of moles (lm_1) of the polyol represented by the above general formula [I] is 2.
While heating an amount of carbonate compound in the range of ~50 in the presence of a basic catalyst, the alcohol (R_3OH) produced is removed from the reaction system by distillation,
After reacting to a reaction rate of 95% or more and then removing the base catalyst, the unreacted carbonate compound [R_4OCO_2R_4 (in the formula,
R_1 (OCOO-R_2), characterized in that R_4 is each independently R_2 or R_3)] is removed from the reaction system by distillation, [wherein R_1 and is the general formula [I ] in R
_1, l are the same, and R_2 is the same as R_2 in general formula [II].