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: 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 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 5.0 bar, preferably 3.5 bar are used. 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.

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 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. 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.

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 sterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. 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.

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 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. 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.

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 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. 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.

Abstract: A method for recovering titanium and vanadium compounds, such as alkoxides, from a liquid hydrocarbon mixture by hydrolyzing the mixture with a base or acid wash having a sufficiently different density so that two liquid phases form, and separating the two liquid phases.