摘要:
The invention provides a process for continuously preparing polyether alcohols using DMC catalysts, which comprises, in a first step, in a continuous reactor, adding alkylene oxides onto H-functional starter substances and transferring the output of this reactor to a second step in a reactor which is divided by closed trays into mutually separate sections, known as compartments, which are connected to one another by external pipelines, in which the output of the reactor from the first step of the reaction passes through the compartments in succession.
摘要:
The invention provides a process for continuously preparing polyether alcohols using DMC catalysts, which comprises, in a first step, in a continuous reactor, adding alkylene oxides onto H-functional starter substances and transferring the output of this reactor to a second step in a reactor which is divided by closed trays into mutually separate sections, known as compartments, which are connected to one another by external pipelines, in which the output of the reactor from the first step of the reaction passes through the compartments in succession.
摘要:
A reactor (1) for gas/liquid or gas/liquid/solid reactions having a vertical longitudinal axis and an inlet (2) for a liquid or liquid/solid feed stream in the upper region of the reactor and an inlet (3) for a gaseous stream in the lower region of the reactor (1), wherein the gaseous stream (3) is conveyed through a gas distributor module (9) which is made up exclusively of straight tube sections (14, 15).
摘要:
A process for preparing hydroxyl-containing polymers and, in particular, a process for preparing polytetrahydrofuran with terminal hydroxyl groups from the corresponding acyloxy-containing polymers by transesterification with alcohols is carried out continuously in at least one stirred vessel, with the foam produced in the transesterification being fed tangentially to a cylindrical container, preferably a cyclone separator, at an adequate velocity to destroy the foam. The liquid phase which separates out is recycled through a line to the at least one stirred vessel.This continuous process is preferably carried out in a cascade of stirred vessels, in which each stirred vessel or a subunit of at least two stirred vessels can in each case be coupled to a cylindrical container, preferably in the form of a cyclone separator.
摘要:
Polyamides, oligomers thereof or mixtures thereof, if required with further reaction products, are prepared by reacting aminonitriles or dinitriles and diamines or a mixture containing aminonitrile, dinitrile and diamine, and, if required, further polyamide-forming monomers and/oligomers with water in a reactor (1) having a vertically oriented longitudinal axis, by a process in which, in the reactor (1), the reaction product is removed from the bottom and ammonia formed and any further low molecular weight compounds formed and water are taken off via the top (2), wherein the reactor (1) has at least two chambers (4) arranged one on top of the other in the longitudinal direction, the chambers (4) being separated from one another by liquid-tight trays (5), each chamber (4) being connected by a liquid overflow (6) to the chamber (4) directly underneath and a liquid product stream being taken off by the liquid overflow (6) of the lowermost chamber (4), the gas space (7) above the liquid level in each chamber (4) being connected to the chamber (4) arranged directly above in each case by one or more conduit pipes (8) which in each case opens or open into a gas distributor (9) having orifices (11) for gas exit below the liquid level, and comprising in each case at least one baffle plate (12) which is arranged vertically around each gas distributor (9) and whose upper end terminates below the liquid level and whose lower end terminates above the liquid-tight tray (5) of the chamber (4) and which separates each chamber (4) into one or more gassed (13) and into one or more ungassed (14) spaces.
摘要:
A process for the manufacture of fibrids of thermoplastics materials by extruding molten thermoplastics through dies and breaking up the extrudate into fibers by means of a liquid medium causing shear stresses within a small volume, to which end the extrudate is passed to a zone of high energy dissipation so that it is completely divided up into fibers of the desired size in a single pass.
摘要:
A reactor (1) for gas/liquid or gas/liquid/solid reactions having a vertical longitudinal axis and an inlet (2) for a liquid or liquid/solid feed stream in the upper region of the reactor and an inlet (3) for a gaseous stream in the lower region of the reactor (1), wherein the gaseous stream (3) is conveyed through a gas distributor module (9) which is made up exclusively of straight tube sections (14, 15).
摘要:
The invention relates to a process for preparing an aqueous powder coating dispersion, which comprises introducing a liquid melt comprising binders and crosslinking agents and also, if desired, catalysts, auxiliaries and further additives such as devolatilizers, UV absorbers, free-radical scavengers and/or antioxidants into an emulsifying apparatus, preferably with the addition of water and stabilizers, and cooling and filtering the resultant emulsion.
摘要:
A process for preparing biphenols of the general formula I by reaction of monophenols of the general formula II where the radicals R1, R2 and R3 are each, independently of one another, hydrogen, alkyl, aryl or arylalkyl having from 1 to 10 carbon atoms, in the presence of an oxidant in a reactor, wherein a) the reactor comprises no stationary internals which act as baffles, b) a total of not more than 0.6 mol of oxidant is used per one mol of monophenol, and c) the oxidant is introduced either continuously or discontinuously in a plurality of portions over a period of from 10 minutes to 24 hours, with the amount of oxidant introduced per unit time not being constant over the total period of time but instead being varied.
摘要:
A process for preparing biphenols of the general formula I by reaction of monophenols of the general formula II where the radicals R1, R2 and R3 are each, independently of one another, hydrogen, alkyl, aryl or arylalkyl having from 1 to 10 carbon atoms, in the presence of an oxidant in a reactor, wherein a) the reactor comprises no stationary internals which act as baffles, b) a total of not more than 0.6 mol of oxidant is used per one mol of monophenol, and c) the oxidant is introduced either continuously or discontinuously in a plurality of portions over a period of from 10 minutes to 24 hours, with the amount of oxidant introduced per unit time not being constant over the total period of time but instead being varied.