Bayer Aktiengesellschaft

Bayer Technology Services Gmbh

Franz Ferdinand Rhiel

Uwe Hucks

Thomas Fischer

Gunther Weymans

Steffen Kuhling

Rolf Bachmann

Gottfried Zaby

Martin Ullrich

Silke Kratschmer

Heinrich Schuchardt

Heinrich Steude

Klaus Schebesta

Klaus Elgeti

Said Mahiout

Martin Gerlach

Lothar Lang

Torsten Hauschild

Frank Meeuwssen

Method for controlling the process of separating mixtures containing several substances having close boiling points and with a known concentration, in a distillation column, wherein the concentration of at least one component is measured at a midpoint of the column, and said measurement, together with other parameters, is used to control the process.

Method for controlling the process of separating mixtures containing several substances

A continuous process for producing oligocarbonate is disclosed. The process entails in sequence the steps of a) reacting a dihydroxyaryl compound with a diaryl carbonate in the presence of a catalyst to obtain a melt and avoiding removal of released monohydroxyaryl compound and b) withdrawing the monohydroxyaryl compound by flash evaporation and c) heating the melt obtained under vacuum in an evaporator equipped with sump receiver and d) repeating at least once steps b) and then c) each at gradually increased temperatures and lowered pressures.

Process for producing oligocarbonates

The invention relates to a two-step melt process for the production of thermoplastic, solvent-free, low-branching polycarbonates with low --OH terminal group content using a self-cleaning high-viscosity reactor.

Two-step process for the production of thermoplastic polycarbonate

The invention relates to a transesterification process for the production of thermoplastic, solventless oligo-/polycarbonates in which aromatic diphenols and carbonic acid diaryl esters are combined and reacted in gaseous form.

Process for the production of thermoplastic polycarbonate

The present invention provides a melt process for the manufacture of thermoplastic solvent-free polycarbonates with the use of a continuously operated tubular reactor for monophenol vaporization.

Process for the manufacture of thermoplastic polycarbonate

A method of controlling concentrations in process technology operations--preferentially in thermal separation technology--using a non-linear, pressure-compensated temperature as control signal. The method can be used flexibly within a wide operating range.

Method of controlling the concentrations of a multicomponent mixture

A method of controlling a heat exchanger wherein the enthalpy flow into the heat exchanger serves as a correcting variable. The robust and versatile control method is particularly suitable for use in endothermic reactions and for distillation.

Method of controlling heat exchangers using enthalpy flow as the

A process for the separation of multicomponent systems containing intermediate boiling substances in separating separating columns with side discharge, the temperatures T.sub.u and T.sub.o above and below the side discharge are measured on the column or inside the column and the temperature difference T.sub.u -T.sub.o is used for controlling the side discharge. The control is carried out by constantly controlling one of the two temperatures T.sub.u or T.sub.o by the output of the evaporator or the discharge from the sump or the reflux or the removal of distillate or the reflux ratio.

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Dormagen, Germany

Franz Ferdinand Rhiel