JP3036713B2 - Method for producing cyclic carbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a cyclic carbonate from a carbonate and a diol. This cyclic carbonate is a useful raw material for synthesizing a polycarbonate by ring-opening polymerization. In particular, it is convenient for graft-polymerizing polycarbonate to various compounds and polymers. These polycarbonates are paints,
It is useful as a modifier for resins used for inks or the like, or for modifying polyurethanes and epoxy resins, and for plastics. Further, the cyclic carbonate can be used for an organic electrolyte.

[0002]

2. Description of the Related Art As a method for producing a cyclic carbonate from a diol, a method for producing a cyclic carbonate from phosgene and a corresponding diol (Journa) is known.
l of American Chemical So
Citiy 80, 4596, (1958),
However, there is a problem in that toxic phosgene is used. In addition, a method for producing a corresponding diol and a carbonate by transesterification has been known for a long time, and a basic catalyst such as sodium alkoxide has been known as a catalyst. (Journa
l of American ChemicalSoc
iety 52,314, (1930), JP-A-64-26576) However, these methods have problems in that the selectivity is not so good and the viscosity of the product is very high, and the pipes are clogged.

[0003]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above problems can be solved by using a reaction solvent, and have accomplished the present invention. That is,
According to the present invention, when a cyclic carbonate is produced by reacting a diol and a carbonate in the presence of a catalyst, the concentration of at least one of the diol and the carbonate is 99 to 0.1%.
This is a method for producing a cyclic carbonate, wherein a solvent is used in an amount of 0001% by weight. The diols in the present invention also include polyols such as triols and tetraols, and specific examples include the following. 1,3-propanediol, 2-methyl-1,3-propanediol, 3-methylpentane 1,3,5-triol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl Glycol, cis-1,3-cyclohexanediol, 2-phenyl-1,3-propanediol and the like are exemplified, but other diols can also be used in the reaction.

The following are examples of the carbonic acid ester in the present invention. Examples thereof include aliphatic carbonic diesters such as dimethyl carbonate, diethyl carbonate and dibutyl carbonate, mixed carbonic esters such as methylphenyl carbonate, ethylphenyl carbonate and methylethyl carbonate, and aromatic carbonic diesters such as diphenyl carbonate and dinaphthyl carbonate.

The ratio of diol to carbonate used in the reaction is 0.01 mole of carbonate to 1 mol of diol.
To 100 mol, preferably 0.5 to 2 mol.

The catalyst which can be used in the present invention includes: inorganic bases such as sodium hydroxide, sodium methoxide and calcium hydroxide; basic catalysts such as organic bases such as pyridine and triethylamine; paratoluenesulfonic acid;
An acid catalyst such as monochloroacetic acid, a cation exchange resin, aluminum chloride, BF3, and tetraalkyl titanate can be used.

Solvents that can be used in the present invention include sulfoxides such as dimethyl sulfoxide, aliphatic hydrocarbons such as decane and dodecane, aromatic hydrocarbons such as benzene, toluene and xylene, nitrobenzene, nitroethane and the like. Preferred are nitrated hydrocarbons, halogenated hydrocarbons such as dichlorobenzene, and ether compounds such as dibutyl ether and anisole. These solvents can be used in combination. In addition, any solvent that does not react under the present reaction conditions can be used. Ketones such as isophorone and cyclohexanone, and esters such as ethyl acetate and methyl acetate can also be used, but are not preferred. In the reaction, the concentration of the raw material is such that at least one weight% of the diol or carbonate ester is 99 to 99%.
It can be performed in the range of 0.0001%, preferably 50%.
~ 1%. Generally, the relationship between the substrate concentration and the selectivity of the target cyclic carbonate is such that the lower the substrate concentration, the better the selectivity.

The reaction can be carried out at a reaction temperature in the range of 20 to 350 ° C.

The reaction may be carried out at normal pressure, but if a sufficient reaction rate cannot be obtained at normal pressure, the reaction can be carried out under elevated pressure at an elevated reaction temperature.

In the reaction, the target compound can be obtained in a higher yield by continuously distilling off the alcohol by-produced by a method such as distillation with the progress of the reaction.

After completion of the reaction, the target compound can be purified from the reaction mixture by a conventional industrial method such as distillation or crystallization. At that time, it is preferable to remove the catalyst in advance by a method such as extraction or washing.

[0012]

Example 1 In a 300-ml flask equipped with a distillation tower equipped with a reflux head, 0.3 mol of neopentyl glycol, 0.45 mol of dimethyl carbonate, 0.3 mmol of sodium methoxide as a catalyst, and 150 g of xylene as a reaction solvent And the reaction was carried out while distilling off an azeotropic component of methanol and dimethyl carbonate from the top of the distillation column. After the theoretical amount of methanol was distilled off, the composition of the reaction solution was analyzed by gas chromatography. As a result, only trace amounts of the starting materials dimethyl carbonate and neopentyl glycol were detected, and the target cyclic carbonate (5,5
-Dimethyl-1,3-dioxan-2-one (DMD
O)) had a selectivity of 87%.

[0013]

Comparative Example 1 The reaction was carried out under the reaction conditions of Example 1 without using xylene as a reaction solvent, and after the theoretical amount of methanol was distilled off, the reaction solution was analyzed by gas chromatography to find that it was a starting material. Although the conversion of neopentyl glycol was 96%, the selectivity of DMDO was 64%.
Met.

[0014]

Comparative Example 2 0.3 mol of neopentyl glycol, 0.33 mol of diethyl carbonate and 0.3 mmol of sodium ethoxide were placed in the reactor of Example 1, and the reaction was carried out while distilling off ethanol from the top of the distillation column. After the theoretical amount of ethanol was distilled off, the reaction mixture was analyzed by gas chromatography. As a result, the conversion of neopentyl glycol was 98%, but the selectivity of DMDO was 56%.

[0015]

Example 2 A reaction was carried out in the same manner as in Example 1 except that the reaction solvent was changed to toluene. After the theoretical amount of methanol was distilled off, the composition of the reaction solution was analyzed by gas chromatography.
Only trace amounts of dimethyl carbonate and neopentyl glycol as raw materials were detected, and the selectivity of DMDO was 88%.

[0016]

Example 3 The reaction was carried out in the same manner as in Example 1 except that the raw material neopentyl glycol was replaced with 1,4-butanediol. After the theoretical amount of methanol was distilled off, the composition of the reaction solution was analyzed by liquid chromatography. As a result, only trace amounts of the starting materials dimethyl carbonate and 1,4-butanediol were detected, and the desired cyclic carbonate (1,3 -Dioxycycloheptane-2-one) was 70%.

[0017]

Comparative Example 3 The reaction was carried out under the reaction conditions of Example 3 without using xylene as a reaction solvent, and after the theoretical amount of methanol was distilled off, the reaction solution was analyzed by liquid chromatography to find that it was a starting material. The conversion of 1,4-butanediol was 95%, but the selectivity for the desired cyclic carbonate (1,3-dioxycycloheptan-2-one) was 23%.

[0018]

Example 4 A reaction was performed in the same manner as in Example 1 except that the raw material neopentyl glycol was replaced with 3-methylpentane-1,3,5-triol. After the theoretical amount of methanol was distilled off, the composition of the reaction solution was analyzed by liquid chromatography, and only trace amounts of dimethyl carbonate and 3-methylpentane-1,3,5-triol as raw materials were detected. Desired cyclic carbonate (4-methyl-4- (2-hydroxyethyl) -1,3-dioxan-2-one)
Was 75%.

[0019]

Comparative Example 4 The reaction was carried out under the reaction conditions of Example 4 without adding xylene as a reaction solvent. As a result, the conversion of the starting material triol was 97%, and the selectivity of the target cyclic carbonate was 45%. .

[0020]

Example 5 A reaction was performed in the same manner as in Example 1 except that the raw material neopentyl glycol was replaced with 1,6-hexanediol. After the theoretical amount of methanol was distilled off, the composition of the reaction solution was analyzed by liquid chromatography. As a result, only trace amounts of dimethyl carbonate and 1,6-hexanediol as the raw materials were detected, and the target cyclic carbonate was detected. (1,3
10,12-Teraoxycyclooctadecane-2,1
The selectivity of 1-dione) was 65%.

[0021]

Comparative Example 5 The reaction was carried out under the reaction conditions of Example 5 without adding xylene as a reaction solvent.
The conversion of 6-hexanediol was 98%, and the selectivity of the target cyclic carbonate was 4%.

[0022]

Example 6 In Example 1, 0.03 mol of neopentyl glycol, 0.045 mol of dimethyl carbonate,
The reaction was carried out by adding 0.03 mmol of sodium methoxide as a catalyst. When the composition of the reaction solution was analyzed by gas chromatography, neopentyl glycol as a raw material was not detected, and the selectivity for the target cyclic carbonate (DMDO) was 99% or more.

[0023]

Example 7 A reaction was carried out by replacing the catalyst of Example 1 with p-toluenesulfonic acid. After the theoretical amount of methanol was distilled off, the composition of the reaction solution was analyzed by gas chromatography. As a result, only trace amounts of dimethyl carbonate and neopentyl glycol as the raw materials were detected, and the selectivity of DMDO was 78%. Was.

[0024]

Comparative Example 6 When the reaction was carried out under the reaction conditions of Example 6 without adding xylene as a reaction solvent, only a trace amount of neopentyl glycol as a raw material was detected, and the selectivity of the target cyclic carbonate (DMDO) was determined. Was 21%.

[0025]

Example 8 A reaction was carried out by replacing the catalyst of Example 7 with tetramethyl titanate. After the theoretical amount of methanol was distilled off, the composition of the reaction solution was analyzed by gas chromatography. As a result, only trace amounts of dimethyl carbonate and neopentyl glycol as the raw materials were detected, and the selectivity of DMDO was 8%.
5%.

[0026]

According to the present invention, when a cyclic carbonate is produced from a diol as a raw material, the reaction solution has a low viscosity and is easy to handle, and the desired cyclic carbonate can be obtained easily, with high yield and high selectivity. it can.

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI B01J 27/125 B01J 27/125 31/02 101 31/02 101 102 102 103 103 103 31/04 31/04 31/08 31/08 31/12 31/12 C07B 61/00 300 C07B 61/00 300 C08G 64/30 C08G 64/30

Claims (1)

(57) [Claims] When producing a cyclic carbonate by reacting a diol with a carbonate in the presence of a catalyst, the concentration of at least one of the diol and the carbonate is 99 to 100%.
A solvent selected from aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, nitrated hydrocarbons, ethers and sulfoxides in a range of 0.0001% by weight, Production method.