Method to produce and purify cyclic esters
AssigneeChronopol, Inc.
InventorsTimothy J. Eggeman, Herman P. Benecke
Life of this patent
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Abstract
Methods are provided for the production, recovery and purification of cyclic esters. Such methods include producing a cyclic ester composition containing at least one impurity, contacting the cyclic ester composition with at least one adsorbent to remove the impurity and recovering the purified cyclic esters. Also included are methods of cyclic ester purification involving multiple adsorption operations. The methods of the present invention can produce highly purified cyclic esters. Such compositions are suitable for use in the manufacture of polymers having an average degree of polymerization in excess of about 1700.
Claims130
A process for producing a cyclic ester, comprising the steps of:
- (a) providing a feedstream comprising XA in a solvent, wherein XA comprises compounds selected from the group consisting of a single hydroxycarboxylic acid or its ester, salt or amide (X.sub.1 A);
- a straight chain two member molecule of X.sub.1 A (X.sub.2 A);
- a straight chain three member molecule of X.sub.1 A (X.sub.3 A);
- a straight chain four member molecule of X.sub.1 A (X.sub.4 A);
- a straight chain five member molecule of X.sub.1 A (X.sub.5 A);
- and mixtures thereof;
- (b) removing water from said feedstream to form a product stream comprising said cyclic ester, wherein the concentration of X.sub.5 A and higher oligomers in said product stream is less than about 20 wt % of the reaction mixture during said process;
- and
- (c) contacting said product stream with a first adsorbent to remove at least one impurity from said product stream selected from the group consisting of free acid, water and mixtures thereof to form a purified product stream.
A method to purify a cyclic ester composition comprising first and second impurities, comprising the steps of:
- (a) contacting said cyclic ester composition with a first adsorbent to remove said first impurity;
- and
- (b) contacting said cyclic ester composition with a second adsorbent to remove said second impurity.
A method to purify a cyclic ester composition comprising contacting said composition with an adsorbent to remove at least one impurity comprising XA, wherein XA comprises compounds selected from the group consisting of a single hydroxycarboxylic acid or its ester, salt or amide (X.sub.1 A);
- a straight chain two member molecule of X.sub.1 A (X.sub.2 A);
- a straight chain three member molecule of X.sub.1 A (X.sub.3 A);
- a straight chain four member molecule of X.sub.1 A (X.sub.4 A);
- a straight chain five member molecule of X.sub.1 A (X.sub.5 A);
- and mixtures thereof, wherein said adsorbent does not degrade cyclic esters in said cyclic ester composition.
A cyclic ester composition, comprising a cyclic ester and less than about 20 ppm water.
A cyclic ester composition, comprising a cyclic ester and free acid in an amount of less than about 0.04 meq/kg cyclic ester.
A packaged cyclic ester product, comprising a cyclic ester, less than about 200 ppm water and less than about 1.0 meq free acid/kg cyclic ester, wherein said product is packaged in a package having a water vapor transmission rate of less than about 0.1 g/(100 in.sup.2)(24 hr) at 100.degree. F. and 90% relative humidity.
A process for the production of polymer, comprising polymerizing cyclic esters at a temperature greater than about 150.degree. C. for less than about 30 hours, whereby the average degree of polymerization of said polymers is greater than about 1700.
A process for the recovery of cyclic esters from a product stream comprising cyclic esters, impurities and solvent;
- (a) evaporating a portion of said solvent to concentrate said product stream, wherein said evaporated solvent comprises amounts of cyclic ester and impurities;
- (b) contacting said evaporated solvent with a first adsorbent to remove at least one impurity from said evaporated solvent selected from the group consisting of free acid, water and mixtures thereof to form a purified solvent stream;
- (c) solvent crystallizing said concentrated product stream using said purified solvent stream.
Dependencies are inferred from the claim text.