# US 4,395,536 A · Preparation of aromatic copolyesters via in situ esterification with isopropenyl esters of an alkyl acid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,395,536 A - Document ID: US4395536A - Status: Granted - Kind: A - Application number: 06/322,147 - Filed: 1981-11-17 - Granted: 1983-07-26 - Earliest claimed: 1981-11-17 - Assignees: Celanese Corporation - Inventors: Larry F. Charbonneau - Web page: https://patentgrep.com/patent/US4395536A ## CPC - C08G 63/605: {the hydroxy and carboxylic groups being bound to aromatic rings} - C08G 63/065: {the hydroxy and carboxylic ester groups being bound to aromatic rings} - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract Provided is a method for preparing aromatic copolyesters involving in situ esterification with an isopropenyl ester of an alkyl acid, e.g., isopropenyl acetate. The process comprises reacting the aromatic hydroxy monomers with an isopropenyl ester of an alkyl acid such as isopropenyl acetate in a polymerization vessel in order to esterify the hydroxy moieties, and then polymerizing the esterified hydroxy monomers with aromatic carboxylic acid monomers in the resultant esterification reaction medium to form the aromatic copolyester. Both the esterification and polymerization reactions can be effectively conducted in the same vessel without having to separate out and/or transfer the esterification products from a separate vessel as the polyester polymerization is conducted in the esterification reaction mixture. The esterification is generally carried out in the presence of an acid esterification catalyst, which is preferably neutralized upon completion of the esterification reaction with a suitable basic neutralizing agent, e.g., barium hydroxide. ## Claims ### Claim 1 A process for preparing an aromatic polyester comprising: (i) reacting at least one aromatic hydroxy moiety containing compound with an isopropenyl ester of an alkyl acid under esterification, reaction conditions, and (ii) reacting the esterified compounds with at least one aromatic acid moiety containing compound in the resultant esterification reaction mixture of (i) under polyester polymerization conditions. ### Claim 2 (depends on 1) The process of claim 1 wherein isopropenyl acetate is reacted with at least one aromatic hydroxy moiety containing compound under acetylation reaction conditions, and then reacting the acetylated compounds with at least one aromatic acid moiety containing compound in the resultant acetylation reaction mixture. ### Claim 3 (depends on 2) The process of claim 2 wherein the aromatic acid is present during the acetylation reaction. ### Claim 4 (depends on 2, 3) The process of claim 2 or 3 wherein at least one of the aromatic acid moiety containing compounds is also at least one of the aromatic hydroxy moiety containing compounds. ### Claim 5 (depends on 2) The process of claim 2 wherein the acetylation reaction is conducted in the presence of a catalytic amount of an acetylation catalyst. ### Claim 6 (depends on 5) The process of claim 5 wherein the acetylation catalyst is a strong acid catalyst selected from the group consisting of p-toluenesulfonic acid, sulfosalicylic acid, methanesulfonic acid, hydrogen chloride, hydrogen bromide, perchloric acid and sulfuric acid. ### Claim 7 (depends on 6) The process of claim 6 wherein said catalyst is selected from the group consisting of p-toluenesulfonic acid and methanesulfonic acid. ### Claim 8 (depends on 6) The process of claim 6 wherein a basic neutralizing agent is added to the acetylation reaction mixture upon termination of the acetylation in order to neutralize the acid catalyst. ### Claim 9 (depends on 8) The process of claim 8 wherein said basic neutralizing agent is metallic hydroxide. ### Claim 10 (depends on 8, 9) The process of claim 8 or 9 wherein the neutralizing agent is barium hydroxide. ### Claim 11 (depends on 2) The process of claim 2 wherein the reaction temperature of the acetylation step (i) is in the range of from about 60.degree. C. to about 130.degree. C. ### Claim 12 (depends on 2) The process of claim 2 wherein the reaction temperature is raised to a temperature in the range of from about 180.degree. to 350.degree. C. upon initiation of the polymerization (ii). ### Claim 13 (depends on 2) The process of claim 2 wherein the reaction temperture during the polymerization step (ii) is in the range of from about 225.degree. to about 350.degree. C. ### Claim 14 (depends on 2) The process of claim 2 wherein the polyester polymerization reaction (ii) is conducted in the presence of a catalytic amount of a polymerization catalyst. ### Claim 15 (depends on 2) The process of claim 2 wherein the polymerization reaction (ii) is conducted under melt polymerization conditions. ### Claim 16 (depends on 2) The process of claim 2 wherein an hydroxy benzoic acid is employed as an aromatic hydroxy moiety containing compound and an aromatic acid. ### Claim 17 (depends on 16) The process of claim 16 wherein p-hydroxy benzoic acid is employed. ### Claim 18 (depends on 2) The process of claim 2 wherein the isopropenyl acetate is reacted in (i) with p-hydroxy benzoic acid and 6-hydroxy-2-naphthoic acid. ### Claim 19 (depends on 18) The process of claim 18 wherein the aromatic acid moiety containing compound of (ii) comprises the acetylated p-hydroxy benzoic acid and 6-hydroxy-2-naphthoic acid. ### Claim 20 (depends on 2) The process of claim 2 wherein the isopropenyl acetate is reacted with p-hydroxy benzoic acid, 6-hydroxy-2-naphthoic acid and an aromatic diol in (i). ### Claim 21 (depends on 20) The process of claim 20 wherein said aromatic diol comprises hydroquinone. ### Claim 22 (depends on 20) The process of claim 20 wherein aromatic acid of (ii) is comprised of an aromatic diacid. ### Claim 23 (depends on 22) The process of claim 22 wherein the aromatic diacid is terephthalic acid. ### Claim 24 (depends on 2) The process of claim 2 wherein the aromatic-hydroxy moiety containing compound is comprised of a hydroxy naphthoic acid. ### Claim 25 (depends on 24) The process of claim 24 wherein the hydroxy naphthoic acid is 6-hydroxy-2-naphthoic acid. ### Claim 26 (depends on 24) The process of claim 24 wherein the isopropenyl acetate is reacted with a hydroxy naphthoic acid and an aromatic diol in (i). ### Claim 27 (depends on 26) The process of claim 26 wherein said aromatic diol is hydroquinone. ### Claim 28 (depends on 26) The process of claim 26 wherein the aromatic acid of (ii) is comprised on an aromatic diacid. ### Claim 29 (depends on 28) The process of claim 28 wherein the aromatic diacid is terephthalic acid. ### Claim 30 A process for preparing a wholly aromatic polyester comprising reacting a hydroxybenzoic acid and a hydroxy naphthoic acid with an isopropenyl ester of an alkyl acid under esterification reaction conditions to thereby esterify the hydroxy moieties of the hydroxy benzoic acid and hydroxy naphthoic acid and then raising the temperature of the reaction mixture to a temperature sufficient to initiate polymerization and conducting the polymerization under polyester polymerization reaction conditions. ### Claim 31 (depends on 30) The process of claim 30 wherein the isopropenyl ester of an alkyl acid is isopropenyl acetate. ### Claim 32 (depends on 31) The process of claim 31 wherein the acetylation is conducted at a temperature in the range of from about 60.degree. C. to about 130.degree. C. and the polymerization is conducted at a temperature in the range of from about 180.degree. C. to about 350.degree. C. ### Claim 33 (depends on 31) The process of claim 31 wherein p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are reacted with isopropenyl acetate at a temperature in the range of from about 60.degree. C. to about 130.degree. C. in the presence of an acid catalyst until acetylation is completed, adding a basic reagent in an amount sufficient to neutralize the acid catalyst and then raising the reaction temperature to a temperature sufficient to initiate polymerization and conducting the polymerization at a temperature in the range of from about 250.degree. C. to about 350.degree. C. ### Claim 34 (depends on 33) The process of claim 33 wherein the acid catalyst is selected from the group consisting of methanesulfonic acid and p-toluenesulfonic acid and the basic reagent is barium hydroxide. ### Claim 35 A process for preparing an aromatic polyester comprising heating at least one aromatic hydroxy compound and at least one aromatic acid compound in the presence of an isopropenyl ester of an alkyl acid at an esterification temperature and then at a polymerization temperature to thereby form the aromatic polyester. ### Claim 36 (depends on 35) The process of claim 35 wherein the isopropenyl ester of an alkyl acid is isopropenyl acetate. ### Claim 37 (depends on 36) The process of claim 36 wherein an acid acetylation catalyst is employed and a basic reagent is added upon completion of acetylation in an amount sufficient to neutralize the acid catalyst. ### Claim 38 (depends on 37) The process of claim 37 wherein the basic reagent is barium hydroxide. ### Claim 39 (depends on 1) The process of claim 1, wherein the aromatic hydroxy moiety containing compound comprises at least one of an aromatic diol or aromatic hydroxy acid, and the aromatic acid moiety containing compound comprises at least one of an aromatic diacid, or aromatic hydroxy acid or derivative thereof.