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:
The invention relates to a process for the preparation of formamides by reacting aromatic amines with a formic acid ester in the presence of a catalyst, wherein the catalyst is a phosphorus-containing acid or a Lewis-acidic metal salt.
摘要:
A process for preparing urethanes by reacting aromatic diamines with a dialkyl carbonate, wherein the alkyl radical of the organic dialkyl carbonate comprises 2-18 carbon atoms and one or more heteroatoms and the reaction is performed in the presence of a catalyst.
摘要:
The invention relates to a process for the work-up of residues from the production of isocyanates, which comprises the steps: a) hydrolysis of the residues by means of water, b) introduction of the reaction product from step a) into a mixer having a heat transfer surface, c) separation of amine and water from the output from step b), d) separation of water and amine.
摘要:
The invention provides a process for the simultaneous preparation of 4,4′-diphenylmethanediamine and also diphenylmethane diisocyanate and polyphenylenepolymethylene polyisocyanates, which comprises the steps a) preparation of a mixture of diphenylmethanediamine and polyphenylenepolymethylenepolyamines by acid condensation of aniline and formaldehyde and subsequent work-up of the mixture, b) splitting-off of part of the mixture prepared in step a), c) distillation of the mixture separated off in step b) in a column, d) recirculation of the bottom product from step c) to the end product from step a) and condensation of the overhead product from step c), e) distillation of the overhead product from step c) in a column, f) recirculation of the overhead product from step e) to the end product from step a), g) isolation of the 4,4′-diphenylmethanediamine obtained as bottom product in step e), h) reaction of the mixture from step a) with phosgene and subsequent work-up of the reaction product.
摘要:
A high-temperature tube furnace for pyrolysis includes a twin-hole ceramic tube including a pyrolysis capillary concentrically arranged within a sintering heat tube which is concentrically arranged within a thermally insulated tube housing. At least one heating tube holding element that is electrically insulative and high-temperature resistant is provided and includes at least three pins disposed radially about the sintering heating tube. Each pin is mounted to the tube housing via a clamp in such a way that the pins are adjustable in the radial direction so that the sintering heating tube is removably disposed between the tips of the pins. The sintering heating tube is connected to a voltage source for applying a heating current to thereto.
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:
The invention provides aprocess for the simultaneous preparation of 4,4′-diphenylmethanediamine and also diphenylmethane diisocyanate and polyphenylenepolymethylene polyisocyanates, which comprises the steps a) preparation of a mixture of diphenylmethanediamine and polyphenylenepolymethylenepolyamines by acid condensation of aniline and formaldehyde and sub-sequent work-up of the mixture, b) splitting-off of part of the mixture prepared in step a), c) distillation of the mixture separated off in step b) in a column, d) recirculation of the bottom product from step c) to the end product from step a) and condensation of the overhead product from step c), e) distillation of the overhead product from step c) in a column, f) recirculation of the overhead product from step e) to the end product from step a), g) isolation of the 4,4′-diphenylmethanediamine obtained as bottom product in step e), h) reaction of the mixture from step a) with phosgene and subsequent work-up of the reaction product.
摘要:
A rack oven includes a rack carrier with a main body ant at least one side support connected to the main body for movement between a rack holding position and a rack transfer position. The main body and side support form a rack receiving channel. The side support may be biased into one of the rack holding and the rack transfer positions.
摘要:
An auxiliary chassis for a motor vehicle is formed as a generally rectangular structure for holding an engine, transmission and other equipment. The auxiliary chassis is mounted to front end structural members at a position spaced from and below the structural member forming a further impact absorbing structure.