GB2038321A

GB2038321A - Carbonates

Info

Publication number: GB2038321A
Application number: GB7939487A
Authority: GB
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1978-12-14
Filing date: 1979-11-14
Publication date: 1980-07-23
Also published as: CA1137102A; DE2949936A1; IT7927636A0; JPS55102539A; GB2038321B; NL7908991A; IT1126409B; FR2444024A1

Abstract

A process for making aromatic carbonates comprising contacting an alcohol, a phenol, carbon monoxide in the presence of a base, and a palladium catalyst.

Description

SPECIFICATION Carbonates This invention relates to a process for making aromatic carbonates.

U. S. Patent No. 3,846,468 describes the preparation of carbonic acid esters by the reaction of an aliphatic and aromatic alcohol with carbon monoxide and oxygen carried out in the presence of copper complexed with an organic molecule.

This invention provides a process for making aromatic carbonates which comprises reacting a C110 alkanol, a phenol and carbon monoxide in the presence of a base, and a palladium catalyst.

The phenol is of the formula RaOH (I) wherein Ra represents an aromatic radical. The Ra radical can be carbocyclic or heterocyclic and may be monocyclic, polycyclic, or fused polycyclic, and can have two or more cyclic systems (monocyclic, polycyclic, or fused polycyclic systems) which are connected to each other by single or double valence bonds, or bi- or multivalent radicals.

The alkanol reactant has the general formula: CnH2n+ (OH) (II) wherein n is a whole number of from 1 to 10. Examples of such alkanols are methanol; ethanol; 1-propanol; 1-hexanol; 2-ethyl-l-hexanol and 1-decanol.

The palladium catalyst is used in the form of an ionic compound or complex.

The base may be a tertiaryamine or an alkali or alkaline earth metal hydroxide, carbonate, acetate or benzoate, including mixtures thereof.

A phase transfer agent may also be employed in the reaction mixture. Preferred are onium halides, especially chlorides or bromides, such as tetrabutyiammonium bromide and tetrabutylphosphonium bromide.

The reaction is preferably carried out under anhydrous conditions. For this purpose it is preferred to use a drying agent, such as a molecular sieve in the reaction mixture.

It is preferred to use, in conjunction with the palladium catalyst a manganese redox co-catalyst of a a-diketone or p-diketone, or mixtures thereof, such as acetylacetone, e.g. manganese(ll)bis(acetylacetonate).

In the following examples, all parts are by weight, and the reaction products were verified by infrared spectrum, C-13 nuclear magnetic resonance and mass spectrometry.

Example! A 50 ml. round bottom flask equipped with carbon monoxide and air inlets and a gas exit was charged with a spin bar, 2.12 g. (10.0 mmol.) ofp-cumylphenol, 0.46 g. (10.0 mmol) of ethanol, 2.0 g. of Linde (Registered Trade Mark) 3A molecular sieves which had been activated by heating to 200"C. in a stream of dry nitrogen for 24 hours, 0.23 g. (1.5 mmol.) of 2,2,6,6,N-pentamethylpiperidine, 0.025 g. (0.1 mmol.) of palladium dibromide, and 0.105 g. (0.3 mmol.) of manganese bis(acetylacetonate). To this was added 0.100 g. of bibenzyl, 0.050 g. of toluene and 25 ml. of methylene chloride. Carbon monoxide and air were bubbled through the stirred solution at room temperature for 16 hours.The mixture was analyzed by LC and VPC and established the presence of the following products: 0.710 g. (2.5 mmol.) of p-cumylphenyl(ethyl) carbonate, 0.047 g. (0.39 mmol.) of diethyl carbonate, and 0.308 g. (0.69 mmol.) of bis(p-cumylphenyl) carbonate.

TABLE I

(9) -o-0c t2co3 :t2c03 c 3 0.710 j. 0.047 M 0.30U 9.

Example II A 50 ml. round bottom flask equipped with carbon monoxide and air inlets and a gas exit was charged with a spin bar, 0.94 g. (10.0 mmol.) of phenol, 0.32 g. (10.0 mmol.) of methanol, 2.0 g. of Linde 3A molecular sieves which had been activated by heating to 200"C. in a stream of dry nitrogen for 24 hours, 0.23 g. (1.5 mmol.) of 1,2,2,6,6-pentamethylpiperidine, 0.025 g. (0.1 mmol.) of palladium dibromide, and 0.075 g. (0.3 mmol.) of manganese bis(acetylacetonate). To this was added 0.100 g. of bibenzyl, 0.050 g. of toluene and 25 ml. of methylene chloride. Carbon monoxide and air were bubbled through the stirred solution at room temperature for 16 hours.The mixture was then analyzed by LC and VPC to obtain the following products: 0.22 g. (1.4 mmol.) of phenyl(methyl) carbonate, 0.15 g. (1.67 mmol.) of dimethyi carbonate, and 0.12 g. (0.69 mmol.) of diphenyl carbonate.

TABLE II

NaOO-C0-O- Hn2CO3 ( )2 0.22 g. 0.l5 9. 0.12 g.

Example 111 A 50 ml. round bottom flask equipped with carbon monoxide and air inlets and a gas exit was charged with a spin bar, 2.12 g. (10.0 mmol.) ofp-cumylphenol, 0.46 g. (10.0 mmol.) of ethanol, 2.0 g. of Linde 3A molecular sieves which had been activated by heating to 200"C. in a stream of dry nitrogen for 24 hours, 0.23 g. (1.5 mmol.) of 1 ,2,2,6,6-pentamethylpiperidine, 0.025 g. (0.1 mmol.) of palladium dibromide, and 0.105 g.

(0.3 mmol.) of manganese bis(acetylacetonate). To this was added 0.100 g. of bibenzyl, 0.050 g. of toluene and 25 ml. of methylene chloride. Carbon monoxide and air were bubled through the stirred solution at room temperature for 16 hours. The mixture was then analyzed by LC and VPC to obtain the following products: 0.374 g. (1.3 mmol.) ofp-cumylphenyl(ethyl) carbonate; 0.057 g. (0.48 mmol.) of diethyl carbonate; and 0.265 g. (0.59 mmol.) of bis(p-cumylphenyl) carbonate.

Example IV A 50 ml. round bottom flask equipped with carbon monoxide and air inlets and a gas exit was charged with a spin bar, 0.94 g. (10.0 mmol.) of p-cumyiphenol, 0.82 g. (10.0 mmol.) of methanol, 2.0 g. of Linde 3A molecular sieves which had been activated by heating to 200 C. in a stream of dry nitrogen for 24 hours, 0.52 g. (1.6 mmol.) oftetrabutylammoniumbromide, 0.10g. (1.3 mmol.) of 50% aqueous caustic, 0.025 g. (0.1 mmol.) of palladium dibromide, and 0.075 g. (0.3 mmol.) of manganese bis(acetylacetonate). To this was added 0.100 g. of bibenzyl, 0.050 g. of toluene and 25 ml. of methylene chloride. Carbon monoxide and air were bubbled through the stirred solution at room temperature for 16 hours. The mixture was then analyzed by LC and VPC to obtain the following products: 0.14 g. (0.9 mmol.) of phenyl (methyl) carbonate; 0.15 g.

(1.67 mmol.) of dimethyl carbonate; and 0.02 g. (0.09 mmol.) of diphenyl carbonate.

Example V A one liter autoclave was charged with 0.90 g. (9.6 mmol.) of phenol, 0.53 g. (1.2 mmol.) of di(triethylphosphine) palladium carbomethoxy chloride, 0.97 g. (9.6 mmol.) triethylamine, 150 ml. of chlorobenzene, and sufficient carbon monoxide to pressure the vessel to 1600 psig. The pressure increased to 2025 psig as the system was heated to 100"C. After one hour, the reaction products were cooled to 28"C.

Analysis of the resulting product established presence of phenyl(methyl) carbonate.

Claims

1. A process for making aromatic carbonates which comprises reacting a C,10 alkanol, a phenol and carbon monoxide in the presence of a base, and a palladium catalyst.

2. A process as claimed in Claim 1, in which the reaction mixture further contains an oxidant and a manganese redox co-catalyst.

3. A process as claimed in Claim 1 or 2 wherein reaction takes place in the presence of a phase transfer agent.

4. A process as claimed in any of Claims 1 to 3 wherein reaction takes place in the presence of a drying agent.

5. A process as claimed in Claim 4 wherein the drying agent is a molecular sieve.

6. A process as claimed in Claim 1 and substantially as hereinbefore described with reference to any of the Examples.

7. Aromatic carbonates when produced by a process as claimed in any of the preceding Claims.