Abstract: The present invention relates to an improved method for the esterification of terephthalic acid with 1,4-butanediol, an improved method for the manufacture of polybutylene terephthalate as well as reactors and devices that are suited for the application in this method.

Abstract: Polyesters such as polyethylene, polypropylene and polybutylene terephthalate are made from melts of precondensates of polyesters by first conducting vapors comprising precondensate components distributed in the form of an aerosol through a polycondensation reactor in which precondensate components are deposited on the reactor wall and in an outlet chamber of the reactor on a separator. Then the deposits are conducted to the unstirred discharge sump. Upper layers of the discharge sump are continuously recirculated in the stirred reactor area and thus subjected to reconversion and further polycondensation.

Abstract: A process for the discontinuous production of granules from polycondensation polymers by precondensation of an oligomer at 5 to 400 mbar and subsequent polycondensation in a stirring reactor and subsequent granulation. In the vicinity of the outlet port, the density of the entraining surfaces lies between 1 and 8 m2 per m3 reactor space and constantly increases with increasing distance from the discharge region. Inside the reactor, there is a viscosity gradient between the region most remote from the discharge port and the zone of the discharge port. The thermal decomposition of the polymer melt flowing out of the reactor is compensated during granulation. The stirring reactor with horizontal longitudinal axis approximately has the shape of a single or double truncated cone. The reactor has rotatable, vertical product entraining surfaces and stationary scrapers between the same.

Abstract: Polyesters such as polyethylene, polypropylene and polybutylene terephthalate are made from melts of precondensates of polyesters by first conducting vapors comprising precondensate components distributed in the form of an aerosol through a polycondensation reactor in which precondensate components are deposited on the reactor wall and in an outlet chamber of the reactor on a separator. Then the deposits are conducted to the unstirred discharge sump. Upper layers of the discharge sump are continuously recirculated in the stirred reactor area and thus subjected to reconversion and further polycondensation.

Abstract: The present invention relates to an improved method for the esterification of terephthalic acid with 1,4-butanediol, an improved method for the manufacture of polybutylene terephtalate as well as reactors and devices that are suited for the application in this method.

Abstract: Disclosed is a method for producing polyesters by means of esterification or re-esterification, precondensation of the esterified/re-esterified product, and polycondensation of the precondensed product at a pressure of 0.2 to 500 mbar and a temperature of 230 to 330° C. According to said method, the vapors formed during precondensation and polycondensation are condensed and the obtained cooled diol is redirected into the condensation stage. In order to improve the degree of separation, the vapors are directed into a bottomless direct contact condenser, the base of which is immersed into the top funnel-shaped section of a barometrically dipped downpipe so as to form an annular space, cooled diol is sprayed into the vapors in the top section of the direct contact condenser, the remaining vapors are recovered via the annular space, and the formed polymer aggregates are removed.

Abstract: The invention relates to a method and a device for producing polyesters such as for example polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate from precondensates. According to said method, vapors comprising precondensate components that are distributed therein in the form of an aerosol are guided through a polycondensation reactor in which precondensate components condense on the reactor wall and on a separator in an exit chamber of the reactor. The condensates are guided to the unstirred discharge sump and the upper layers of the discharge sump are continuously recirculated into the stirred reactor area thereby subjecting them to reconversion and additional polycondensation.

Abstract: The invention relates to a method and a device for producing polyesters such as for example polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate from precondensates. According to said method, vapors comprising precondensate components that are distributed therein in the form of an aerosol are guided through a polycondensation reactor in which precondensate components condense on the reactor wall and on a separator in an exit chamber of the reactor. The condensates are guided to the unstirred discharge sump and the upper layers of the discharge sump are continuously recirculated into the stirred reactor area, thereby subjecting them to reconversion and additional polycondensation.

Abstract: In the continuous production of polyesters, the esterification/transesterification of dicarboxylic acids or esters of the dicarboxylic acids with diols is performed in at least one reaction stage, the prepolycondensation of the esterification/transesterification product is performed under a vacuum in a reaction stage consisting of a vertical tube, and the polycondensation of the prepolycondensation product is performed in at least one reaction stage.

Abstract: Process for producing polyesters and copolyesters, wherein a continuous esterification of dicarboxylic esters and diols or a continuous transesterification of dicarboxylic esters with diols is effected in “n” reaction pressure stages connected in series, the pressure in the first reaction pressure stage is higher than that of the remaining reaction pressure stages, and successively decreases from reaction pressure stage to succeeding reaction pressure stage, the combined vapor flows of the individual reaction pressure stages are rectified in a rectifying column, and the diol component obtained at the bottom of the rectifying column is recirculated at least to the first reaction pressure stage, and wherein at least the last reaction pressure stage operates at a vacuum, the pressure in the rectifying column is greater than that of the last reaction pressure stage, and the vapors discharged from the last reaction pressure stage are condensed to the pressure existing in the rectifying column.

Abstract: In a process for producing polyester, the esterification of dicarboxylic acids and diols is carried out in at least one reaction stage, the prepolycondensation of the esterification product in at least one reaction stage and the polycondensation of the prepolycondensation product in at least one reaction stage. To increase the capacity of the apparatus forming one or more of the reaction stages in the production of the polyesters, at at least one of the reaction stages the supplied product system before it enters the reaction stage or within the reaction stage is divided into at least two partial streams and the partial streams entirely or partially separate from one another are passed through the reaction stage.

Abstract: In a method for the continuous pre-polycondensation of esterification/transesterification products the stream freely passes from top to bottom in a vertical reaction apparatus through a plurality of attached, heatable, sloped open-above bases, through product overflow channels connected with each other. In order to be able to set a determined, efficient as possible product level in the channels, the esterification/transesterification products are fed though closed, annular-type, concentric annular channels or through parallel channels, wherein a partial quantity of the product stream flowing in the channel is discharged at the product overflows and the remaining product stream is passed via drainage openings.

Abstract: In the continuous production of polyesters, the esterification/transesterification of dicarboxylic acids or esters of the dicarboxylic acids with diols is performed in at least one reaction stage, the prepolycondensation of the esterification/transesterification product is performed under a vacuum in a reaction stage consisting of a vertical tube, and the polycondensation of the prepolycondensation product is performed in at least one reaction stage.

Abstract: In a process of producing PBT, a mixture of BDO and TPA is esterified in the presence of a catalyst solution, and the esterification product is polycondensated. To avoid the formation of deposits in the PBT, the catalyst solution contains 0.05 to 10 wt-% alkyl titanate, 85 to 99 wt-% BDO, 50 to 50,000 ppm bifunctional carboxylic acid equivalents and/or monofunctional hydroxycarboxylic acid equivalents and not more than 0.5 wt-% water.

Abstract: In a process for producing polyester, the esterification of dicarboxylic acids and diols is carried out in at least one reaction stage, the prepolycondensation of the esterification product in at least one reaction stage and the polycondensation of the prepolycondensation product in at least one reaction stage. To increase the capacity of the apparatus forming one or more of the reaction stages in the production of the polyesters, at at least one of the reaction stages the supplied product system before it enters the reaction stage or within the reaction stage is divided into at least two partial streams and the partial streams entirely or partially separate from one another is passed through the reaction stage.

Abstract: Polycarbonates are produced by reacting a monomeric carbonate component with at least one diphenol or dialcohol in the presence of a transesterification catalyst, wherein the molten component is mixed with the transesterification catalyst by stirring and a transesterification product is produced, which is polycondensated. For polycondensation, the transesterification product is passed through a preliminary reactor, at least one intermediate reactor and one final reactor, the reactors being connected in series and having a substantially horizontal driven shaft with stirrers attached thereto. It is ensured that in the preliminary reactor and in the final reactor a dwell time of the melt of 5 minutes to 2 hours is maintained, that the temperatures in the preliminary reactor are maintained in the range from 220 to 300° C. and in the final reactor in the range from 240 to 350° C.

Abstract: In a process of producing PBT, a mixture of BDO and TPA is esterified in the presence of a catalyst solution, and the esterification product is polycondensated. To avoid the formation of deposits in the PBT, the catalyst solution contains 0.05 to 10 wt-% alkyl titanate, 85 to 99 wt-% BDO, 50 to 50,000 ppm bifunctional carboxylic acid equivalents and/or monofunctional hydroxycarboxylic acid equivalents and not more than 0.5 wt-% water.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic, titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.25 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 245 to 260° C. as well as a pressure of 1 to 3.5 bar are adjusted. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm. For generating the vacuum in the polycondensation and in the precondensation, there are used vapor jet pumps operated with TMG vapor.

Abstract: Polycarbonates are produced by reacting a monomeric carbonate component with at least one diphenol or dialcohol in the presence of a transesterification catalyst, wherein the molten component is mixed with the transesterification catalyst by stirring and a transesterification product is produced, which is polycondensated. For polycondensation, the transesterification product is passed through a preliminary reactor, at least one intermediate reactor and one final reactor, the reactors being connected in series and having a substantially horizontal driven shaft with stirrers attached thereto. It is ensured that in the preliminary reactor and in the final reactor a dwell time of the melt of 5 minutes to 2 hours is maintained, that the temperatures in the preliminary reactor are maintained in the range from 220 to 300° C. and in the final reactor in the range from 240 to 350° C.

Abstract: Process for producing polyesters and copolyesters, wherein a continuous esterification of dicarboxylic esters and diols or a continuous transesterification of dicarboxylic esters with diols is effected in “n” reaction pressure stages connected in series, the pressure in the first reaction pressure stage is higher than that of the remaining reaction pressure stages, and successively decreases from reaction pressure stage to succeeding reaction pressure stage, the combined vapor flows of the individual reaction pressure stages are rectified in a rectifying column, and the diol component obtained at the bottom of the rectifying column is recirculated at least to the first reaction pressure stage, and wherein at least the last reaction pressure stage operates at a vacuum, the pressure in the rectifying column is greater than that of the last reaction pressure stage, and the vapors discharged from the last reaction pressure stage are condensed to the pressure existing in the rectifying column.