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.
摘要:
The invention relates to an apparatus for the galvanic deposition of a metal layer on a substrate and comprises a substrate holder connected to a drive shaft that extends in a direction perpendicular to a surface of the substrate. The cathode current is supplied to the substrate by the drive shaft. The drive shaft has an outer insulating layer. The substrate is held in contact with a contact plate by a supporting ring on the outer periphery of a supporting plate. The contact plate rests on a base of the supporting plate and has a central sleeve connectable with the drive shaft. A mounting portion is provided in the base around the sleeve and a tube portion is inserted into the mounting portion in a sealing and detachable manner. An internally threaded ring is arranged on the drive shaft and is shiftable along the longitudinal axis of the drive shaft. The internally threaded ring is detachably connectable to the tube portion and seals the tube portion and the drive shaft from intrusion of the electrolyte material.
摘要:
A process for coproducing di- and/or polyisocyanates and glycols, comprising process stages A, B, C and E for preparing glycols and process stages A, C, D, E, F and G for preparing di- and/or polyisocyanates,which comprises accomplishing the material coupling via the separation of the reaction mixture obtained in process stage A into process stages B and C, by in process stage A, reacting an aqueous alkylene oxide with carbon dioxide to give a reaction mixture comprising alkylene carbonate, hydrolyzing a portion of the alkylene carbonate-comprising reaction mixture obtained in process stage A to glycol in process stage B, dewatering the remaining alkylene carbonate-comprising stream of the reaction mixture from process stage A in process stage C, in process stage D, synthesizing amine by hydrogenating an aromatic nitro compound or a nitrile, in process stage E, transesterifying the dewatered alkylene carbonate-comprising mixture from process stage C with a monohydroxy alcohol to give the corresponding dialkyl carbonate, obtaining glycol as a coproduct, in process stage F, reacting the dialkyl carbonate-comprising reaction mixture obtained in process stage E with the amine obtained in process stage D to a mixture comprising the corresponding mono-, di- and/or polycarbamate, which in process stage G is cleaved to obtain the corresponding di- and/or polyisocyanate.