Method of manufacturing polyester resins
The subject of the invention is a method to manufacture polyester resins using a by-product formed during a process of oxidizing cyclohexane to cyclohexanol and cyclohexanone, which contains a mixture of carboxyl acids; the method comprises a heating process with the removal of water and low-boiling residues as well as a polycondensation process with di- and polyhydroxy alcohols under a reduced pressure; the method described is characterized by that a water layer is applied as a baseline material in the synthesis; the said water layer is separated from the residues left over after the hydrolysis of cyclohexyl esters contained in the cyclohexane oxidation product, and after the main components, cyclohexanol and cyclohexanon, have been first separated from the said product: thereafter, the water layer is condensed.
1. The method to manufacture polyester resins using a by-product formed during a process of oxidizing cyclohexane to cyclohexanol and cyclohexanone, which contains a mixture of carboxyl acids, and this method comprises a heating process with the removal of water and low-boiling residues, as well as polycondensation process with di- and polyhydroxy alcohols under a reduced pressure, wherein a baseline material in the polycondensation process is a water layer separated from the residues left over after the hydrolysis of cyclohexyl esters contained in the cyclohexane oxidation product, and after the main components, cyclohexanol and cyclohexanon, have been, at first, separated from the said product: thereafter, the water layer is condensed,
wherein
the baseline material used contains adipic acid amounting to 20-27% by weight, 6-hydroxycaproic acid amounting to 10-15% by weight; valeric acid amounting to 10-13% by weight, butyric acid amounting to maximum 45% by weight, acetic acid in the amount of 2-3% by weight, hexanoic (caproic) acid in the amount of 1 to 3% by weight; formic acid amounting to max 1.5% by weight, succinic acid amounting to maximum 1% by weight, propanoic (propionic) acid in the amount of max 1% by weight, isovaleric acid amounting to max 0.5% by weight, other non-identified compounds in the amount of 24-25% by weight such as:
oligomers, ketoacids, cyclohexanone dimmers, and other compounds including tar substances, and water amounting to 10-22% by weight in terms of total weight of the mixture.
2. A method to manufacture polyester resins using a by-product formed during a process of oxidizing cyclohexane to
cyclohexanol and cyclohexanone, which contains a mixture of carboxyl acids, and this method comprises a heating process with the removal of water and low-boiling residues, as well as polycondensation process with di- and polyhydroxy alcohols under a reduced pressure, wherein a baseline material in the polycondensation process is a water layer separated from the residues left over after the hydrolysis of cyclohexyl esters contained in the cyclohexane oxidation product, and after the main components, cyclohexanol and cyclohexanon, have been, at first, separated from the said product: thereafter, the water layer is condensed,
which further contains a monocarboxyl acids that
contains from 1 to 6 carbon atoms in the molecule, amounting to 20-30% by weight, especially hydroxycaproic acids, dicarboxylic acids, that contain from 3 to 6 carbon atoms in the molecule, amounting to 25-40% by weight, especially adipic acids; cyclohexyl esters of these acids, keto acids and other unidentified compounds amounting to 15-25° % by weight and 10-20 weight percent of water, by heating their and polycondensation with di- and polyhydroxy alcohols under a reduced pressure or normal pressure, at a temperature of 160-270 deg. C. characterized in that, in the polycondensation process a water layer separated from the residues left over after the hydrolysis of cyclohexyl esters contained in the cyclohexane oxidation product, and after the main components, cyclohexanol and cyclohexanon, have been, at first, separated from the said product; thereafter, the water layer is condensed in known manner, wherein a water layer contains: adipic acid amounting to 20-27% by weight, 6-hydroxycaproic acid amounting to 10-15% by weight, valeric acid amounting to 10-13% by weight, butyric acid amounting to maximum 4.5% by weight, acetic acid in the amount of 2-3% by weight, hexanoic (caproic) acid in the amount of 1 to 3% % by weight, formic acid amounting to maximum 1.5% by weight, succinic acid amounting to maximum 1% by weight, propanoic (propionic) acid in the amount of maximum 1% by weight, isovaleric acid amounting to maximum 0.5% by weight, other non-identified compounds in the amount of 24-25% by weight such as oligomers, ketoacids, cyclohexanone dimmers, and other compounds including tar substances, and water amounting to 10-22% by weight in terms of total weight of the mixture, wherein
monofunctional compounds can be recovered in the form of a by-product during the polycondensation phase and that by-product might be utilized as a raw material in other synthesis reactions or might be used as a commercial product.
3. The method to manufacture polyester resins using a by-product formed during a process of oxidizing cyclohexane to cyclohexanol and cyrclohexanone, which contains a mixture of carboxyl acids, and this method comprises a heating process with the removal of water and low-boiling residues, as well as polycondensation process with di- and polyhydroxy alcohols under a reduced pressure, wherein a baseline material in the polycondensation process is a water layer separated from the residues left over after the hydrolysis of cyclohexyl esters contained in the cyclohexane oxidation product, and after the main components, cyclohexanol and cyclohexanon, have been, at first, separated from the said product: thereafter, the water layer is condensed,
wherein
a monofunctional compounds can be recovered in the form of a by-product during the polycondensation phase and that by-product might be utilized as a raw material in other synthesis reactions or might be used as a commercial product.