# US 5,349,048 A · Preparation of polycarbonate products

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- Number: US 5,349,048 A
- Document ID: US5349048A
- Status: Granted
- Kind: A
- Application number: 08/173,233
- Filed: 1993-12-27
- Granted: 1994-09-20
- Earliest claimed: 1991-04-29
- Assignees: Monsanto Company
- Inventors: William D. McGhee; Dennis P. Riley
- Web page: https://patentgrep.com/patent/US5349048A

## CPC

- C07C 269/04: from amines with formation of carbamate groups
- C07C 68/04: from carbon dioxide or inorganic carbonates
- C08G 64/323: {and alcohols}
- C08G 71/04: Polyurethanes
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

The present invention provides a process for preparing urethanes and carbonates from an amine or an alcohol, carbon dioxide and a hydrocarbyl halide. The amine or alcohol is reacted with carbon dioxide in a suitable solvent system and in the presence of an amidine or guanidine base, to form the ammonium carbamate or carbonate salt which is then reacted in a polar aprotic solvent with a hydrocarbyl halide. Polymer products can also be prepared utilizing this process or utilizing the resulting urethanes and carbonates under standard polymerization conditions.

## Claims

### Claim 1

A process for preparing polycarbonate comprising:
(a) bringing CO.sub.2 and alcohol into reactive contact in a suitable solvent and in the presence of a sterically hindered amidine or guanidine base to form the corresponding carbonate salt;
(b) reacting, in a polar aprotic solvent, the salt with a hydrocarbyl halide; and
(c) reacting the product of Step (b) with a polymerization initiator under polymerization conditions.

### Claim 2 (depends on 1)

The process of claim 1 wherein said solvent is selected from the group consisting of dimethylformamide, dimethylsulfoxide, acetonitrile, N-methyl-2-pyrrolidone and mixtures thereof.

### Claim 3 (depends on 2)

The process of claim 2 wherein said solvent is acetonitrile.

### Claim 4 (depends on 2)

The process of claim 2 wherein said solvent is dimethylformamide.

### Claim 5 (depends on 1)

The process of claim 1 wherein said hydrocarbyl halide is a primary or secondary hydrocarbyl halide represented by the formula R.sub.1 X or XR.sub.1 X, wherein R.sub.1 represents alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl and aralkenyl radicals having 1 to about 22 carbon atoms, provided that R.sub.1 is other than a tertiary radical of the formula (R).sub.3 C-- or (R).sub.2 C.dbd.(R)--; and X represents a halide.

### Claim 6 (depends on 5)

The process of claim 5 wherein X is chloride.

### Claim 7 (depends on 1)

The process of claim 1 wherein said sterically hindered base is a guanidine base.

### Claim 8 (depends on 1)

The process of claim 1 wherein said base is selected from the group consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and N-cyclohexyl-N',N',N",N"-tetramethyl quanidine.

### Claim 9

A process for preparing polycarbonates comprising:
(a) bringing CO.sub.2 and a diol or polyol into reactive contact in a suitable solvent and in the presence of a strongly basic nitrogenous compound selected from the group consisting of amidine compounds and guanidine compounds to form the corresponding carbonate salt; and
(b) reacting the salt in a polar aprotic solvent with a hydrocarbyl dihalide or hydrocarbyl poly(halide).

### Claim 10 (depends on 9)

The process of claim 9 wherein said polar aprotic solvent has a dielectric constant at 20.degree. C. of at least about 30.

### Claim 11 (depends on 10)

The process of claim 10 wherein said polar aprotic solvent has a dielectric constant at 20.degree. C. of at least about 35.

### Claim 12 (depends on 11)

The process of claim 11 wherein said polar aprotic solvent is selected from the group consisting of acetonitrile and dimethylformamide.

### Claim 13 (depends on 9)

The process of claim 9 wherein said hydrocarbyl dihalide or hydrocarbyl poly(halide) is a hydrocarbyl dichloride or hydrocarbyl poly(chloride).

### Claim 14 (depends on 9)

The process of claim 9 wherein said basic nitrogenous compound is a guanidine base.