摘要:
The invention relates to a method for purifying mixtures comprising 4,4′-methylenediphenyl diisocyanate, which comprises purifying by distillation a mixture I comprising 4,4′-methylenediphenyl diisocyanate having a hydrolyzable chlorine content as specified in ASTM D4663-10 of greater than 100 ppm by means of a column K1, wherein the gaseous stream comprising the mixture I is brought into contact in the column K1 with at least one liquid compound A which has the same or higher boiling point than 4,4′-methylenediphenyl diisocyanate and which has a hydrolyzable chlorine content as specified in ASTM D4663-10 of a maximum of 100 ppm, and wherein the gaseous stream O obtained at the top of the column comprises 4,4′-methylenediphenyl diisocyanate has a hydrolyzable chlorine content as specified in ASTM D4663-10 of a maximum of 100 ppm.
摘要:
The present invention relates to a process for the production of isocyanates, preferably diisocyanates and polyisocyanates of the diphenylmethane series (MDI), by reacting an amine with phosgene in the liquid phase or in the gas phase to form the corresponding isocyanates, subsequent removal of the solvent in at least two steps to obtain at least two solvent streams, individual treatment of the at least two solvent streams, and re-circulation of at least a portion of the solvent streams.
摘要:
The present invention relates to a process for the production of isocyanates, preferably diisocyanates and polyisocyanates of the diphenylmethane series (MDI), by reacting an amine with phosgene in the liquid phase or in the gas phase to form the corresponding isocyanates, subsequent removal of the solvent in at least two steps to obtain at least two solvent streams, individual treatment of the at least two solvent streams, and recirculation of at least a portion of the solvent streams.
摘要:
The invention relates to a process for preparing methylenedi(phenyl isocyanate), which comprises (a) the phosgenation of two-ring and/or multiring methylenedi(phenylamine), (b) the fractionation of the crude methylenedi(phenyl isocyanate) obtained to give two-ring and multiring isomers, (c) the purification and/or fractionation of the resulting mixture of two-ring isomers of methylenedi(phenyl isocyanate) and (d) the storage of the mixtures obtained in step (c) or in step (b), wherein part of the stored mixtures is reused by means of recirculation in at least one of steps (b) or (c).
摘要:
A process is proposed for preparing isocyanates by thermally cleaving carbamates to obtain a carbamate cleavage gas comprising the corresponding isocyanate and the corresponding alcohol, which comprises quenching the carbamate cleavage gas in the presence of an ether which functions as an inhibitor for the reverse reaction of the isocyanate with the alcohol.
摘要:
The present invention relates to an implantable chamber (1) with a connecting element (2), comprising a connecting sleeve (6) and a surrounding contact surface (7), an insert element (3), comprising an insert sleeve (8) and a surrounding abutment surface (9). The insert sleeve (8) is inserted into the connecting sleeve (6) of the connecting element (2). The implantable chamber (1) further comprises a cap (4) with a surrounding edge (11), the cap (4) partly covering the connecting element (2) and the insert element (3), leaving an opening (13) on one side. The implantable chamber (1) contains a passive resonance circuit (14) with an inductance and a capacitance, the passive resonance circuit (14) surrounding at least part of a cavity (15) inside the insert element (3).
摘要:
A pipe anchor having: a base cradle with a lug; a top cradle with a lug and secured to the base cradle so as to encircle a pipe within the base cradle and the top cradle; a locking mechanism with opposite mating components attached to the base cradle and the top cradle; at least one lug attached to the pipe; and insulation material filling a space between the pipe and the cradles, wherein the insulation material engages the at least one lug of the pipe and the lugs of the cradles.
摘要:
A process is proposed for preparing isocyanates by thermally cleaving carbamates to obtain a carbamate cleavage gas comprising the corresponding isocyanate and the corresponding alcohol, which comprises quenching the carbamate cleavage gas in the presence of an ether which functions as an inhibitor for the reverse reaction of the isocyanate with the alcohol.
摘要:
The invention relates to a process for obtaining a dialkyl carbonate and an alkylene glycol from a stream comprising dialkyl carbonate, alkylene carbonate, alkylene glycol and alcohol, comprising the following steps: (a) distillatively removing a stream (5) comprising dialkyl carbonate and alkylene glycol as a heteroazeotrope from the stream comprising dialkyl carbonate, alkylene carbonate, alkylene glycol and alcohol in a first distillation stage (1), (b) separating the stream (5) comprising dialkyl carbonate and alkylene glycol as a heteroazeotrope into a first crude product stream (27) comprising essentially di-alkyl carbonate and a second crude product stream (29) comprising essentially alkylene glycol in an apparatus for phase separation (25).