摘要:
A process for purifying an aqueous glyoxal solution comprising at least one acid by extractive acid removal, comprising the steps of i) mixing and dispersion of the aqueous glyoxal solution with an ion exchanger solution comprising 20 to 60% by weight of a tertiary amine and 80 to 40% by weight of an organic solvent which does not have unlimited miscibility with water at a temperature of 30 to 100°C, ii) phase separation and removal of the ion exchanger solution laden with the acid from the aqueous glyoxal solution at temperatures of 30 to 100°C, and iii) regeneration of the ion exchanger solution by contacting with a basic compound for neutralization of the acid and removal of the basic compound, iv) mixing and dispersion of the ion exchanger solution with water to free it of salts formed in the neutralization to obtain a dispersion of water and ion exchanger solution, v) phase separation and removal of the aqueous phase from the ion exchanger solution, and recycling of the ion exchanger solution into step i), which comprises phase separation and removal of the aqueous phase in step v) in such a way that the content of the aqueous phase of the regenerated ion exchanger solution obtained in step v) is
摘要:
A process is proposed for preparing chlorine by oxidizing hydrogen chloride in the presence of a heterogeneous particulate catalyst by the Deacon process in a fluidized bed reactor (1), wherein the heat of reaction is removed by evaporative cooling with water which circulates in the tubes (2) of a shell and tube heat exchanger, wherein the water is supplied from a steam drum (4) via a feed line (5) to the tubes (2) of the shell and tube heat exchanger at one end thereof, it heats up in the tubes (2) by absorbing the heat of reaction and evaporates partly to obtain a water/steam mixture which is passed back into the steam drum (4) via a return line (6) at the other end of the tubes (2) of the shell and tube heat exchanger, which is characterized in that the maximum pressure for which the fluidized bed reactor (1) has to be designed for the event of fracture of a tube (2) of the shell and tube heat exchanger is minimized by introducing a valve (7) into the feed line (5) and into the return line (6), said valve (7), in the event of a pressure rise owing to the fracture of a tube (2), blocking the feed line (5) and the return line (6), thus preventing water from flowing out of the steam drum (4) into the fluidized bed reactor (1).
摘要:
The invention relates to a method for producing isocyanates by converting the corresponding amine with phosgene in the gas phase, in the presence of an inert medium as applicable, wherein phosgene and amine are first vaporized and then overheated to reaction temperature, the overheated phosgene and amine are mixed and added to a reactor wherein the phosgene and the amine are converted to isocyanate, wherein the dwell time of the phosgene at temperatures greater than 300°C equals a maximum of 5 sec and/or the temperature of heat transfer surfaces in contact with the phosgene is 20 K above the phosgene temperature to be set at maximum. The invention further relates to a device for producing isocyanates by converting the corresponding amine with phosgene in the gas phase.
摘要:
The present invention relates to a method for producing carotenoid solutions in an oil suitable for food. In particular, the invention relates to a method for dissolving a carotenoid, in particular astaxanthin, in an oil suitable for food by heating a suspension of the carotenoid, especially astaxanthin, in the oil and then rapidly cooling (quenching) the obtained solution. The method comprises the following steps: i. providing a suspension of the carotenoid in an oil suitable for food; ii. continuously heating a flow of the carotenoid suspension, wherein a hot carotenoid solution is obtained; and iii. continuously rapidly cooling the hot carotenoid solution, wherein the carotenoid suspension is conducted over a heated heat exchanger surface as a thin liquid film in order to continuously heat the carotenoid suspension.
摘要:
The invention relates to a method for obtaining cyclododecatriene (CDT) from a solution containing CDT and high-boiling components such as a deactivated catalyst and polymers. Said solution is supplied to a preheater and heated, and is then relaxed over a downstream pressure maintaining device, and the two-phase mixture obtained is supplied to a spiral tube evaporator where the CDT content of the liquid phase is reduced by partial evaporation and a gaseous product flow with an increased CDT concentration is derived.
摘要:
A method is disclosed for transferring heat to a liquid F containing dissolved monomeric acrylic acid, acrylic acid oligomers obtained by Michael addition, and acrylic acid polymer with the help of an indirect heat exchanger to which the liquid F is fed at a temperature T F ≥ 150°C and a heat transfer fluid W is fed at a temperature T w > T F . In said method, gas bubbles or thin layers of liquid F bordering a gas phase are generated in the liquid F while said liquid F flows through the heat exchanger.
摘要:
The invention relates to a method for producing polyisocyanates, comprising the following steps: a) amines are reacted with phosgene; b) hydrogen chloride, excess phosgene, and, if necessary, the solvent are separated from the reaction mixture; c) the liquid mixture from step b) is separated into a liquid and a gaseous phase; d) the gaseous phase from step c) is processed into the polyisocyanate.