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US 6,887,953 B2Granted
Esterification process
AssigneeE.I. du Pont de Nemours and Company
InventorJohn Harvey Eng
Life of this patent
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AssigneeE.I. du Pont de Nemours and Company
InventorJohn Harvey Eng
Estimating the term…
A process that can be used for direct esterification of a dicarboxylic acid such as terephthalic acid with a glycol such as 1,3-propanediol. The process comprises (1) contacting, at an elevated temperature, optionally in the presence of a preformed oligomer, the acid with the glycol to produce a product mixture comprising (i) a water-glycol vapor mixture, which or a portion of which exits the product mixture at the temperature to form a water-glycol vapor mixture and (ii) a liquid product mixture comprising an oligomer having a degree of polymerization of from about 1.9 to about 3.5 and comprising repeat units derived from the acid; (2) separating the glycol from the water-glycol mixture to produce a recovered glycol; and (3) returning the recovered glycol to the product mixture such that the liquid product mixture comprises an excess free glycol.
A process comprising contacting, at an elevated temperature, a dicarboxylic acid with a glycol to produce a product mixture comprising (i) a water vapor mixture comprising water and volatile glycol, said water vapor mixture or a portion thereof exits said product mixture to form a water-glycol vapor and (ii) liquid product mixture comprising free glycol and an oligomer having a degree of polymerization of from about 1.9 to about 3.5 and comprising repeat units derived from the acid.
A process comprising (1) continuously contacting, at about 220 to about 260° C. terephthalic acid with 1,3-propanediol to produce a product mixture comprising (i) a water vapor mixture comprising vapor of said 1,3-propanediol, said water vapor mixture or a portion thereof exits said product mixture to form an water-glycol vapor and (ii) a liquid product mixture comprising free 1,3-propanediol and an oligomer having a degree of polymerization of from 1.9 to 3.5 and comprising repeat units derived from said terephthalic acid and 1,3-propanediol;
A continuous process for esterifying terephthalic acid with 1,3-propanediol comprising (1) contacting, at a temperature of about 235° C. to about 255° C., said terephthalic acid, in a single stage esterifier, with 1,3-propanediol sufficient to convert at least 95% of said terephthalic acid to produce a product mixture comprising (i) a water vapor mixture comprising 1,3-propanediol vapor and (ii) a liquid product mixture comprising an oligomer comprising repeat units derived from said terephthalic acid and said 1,3-propanediol and has a degree of polymerization of from 1.9 to 3.5 ;
A continuous process for esterifying terephthalic acid with 1,3-propanediol comprising contacting, under a pressure in the range of from 100 to 400 KPa, said terephthalic acid, in a single stage esterifier, with 1,3-propanediol sufficient to convert at least 95% of said terephthalic acid to produce a product mixture comprising (i) a water vapor mixture comprising unreacted 1,3-propanediol mixture and (ii) a liquid product mixture comprising an oligomer comprising repeat units derived from said terephthalic acid and said 1,3-propanediol and has a degree of polymerization of from 1.9 to 3.5.
Dependencies are inferred from the claim text.