摘要:
The present invention relates to a process for the production of mixtures of di- and polyamines of the diphenylmethane series (MDA) containing less than 1,000 ppm of water and less than 200 ppm of aniline by reaction of aniline and formaldehyde in the presence of acid catalysts and subsequent separation of the acid catalyst and subsequent distillative separation of water and aniline in an at least a two-stage distillation including a flash evaporation and subsequent cooling.
摘要:
The present invention relates to a process for the production of mixtures of di- and polyamines of the diphenylmethane series (MDA) containing less than 1,000 ppm of water and less than 200 ppm of aniline by reaction of aniline and formaldehyde in the presence of acid catalysts and subsequent separation of the acid catalyst and subsequent distillative separation of water and aniline in an at least a two-stage distillation including a flash evaporation and subsequent cooling.
摘要:
High boiling contaminants such as chloro-aromatic compounds are removed from a gas by compressing the gas containing the contaminant, cooling the compressed gas to reduce the temperature of the gas to at least 20° C. above the outlet temperature of a second cooling stage but above the freezing point of the highest melting compound in the first cooling stage, further cooling the gas in a second cooling stage to at least −20° C., returning cooled gas from the second cooling stage to the first cooling stage, and recovering condensate streams which contain the contaminant compound from the first and second cooling stages. An apparatus suitable for carrying out this process is also disclosed. The process of the present invention is particularly useful for removing chloro-aromatic compounds from anhydrous hydrogen chloride gas.
摘要:
High boiling contaminants such as chloro-aromatic compounds are removed from a gas by compressing the gas containing the contaminant, cooling the compressed gas to reduce the temperature of the gas to at least 20° C. above the outlet temperature of a second cooling stage but above the freezing point of the highest melting compound in the first cooling stage, further cooling the gas in a second cooling stage to at least −20° C., returning cooled gas from the second cooling stage to the first cooling stage, and recovering condensate streams which contain the contaminant compound from the first and second cooling stages. An apparatus suitable for carrying out this process is also disclosed. The process of the present invention is particularly useful for removing chloro-aromatic compounds from anhydrous hydrogen chloride gas.
摘要:
A mixture of materials having different boiling points is separated into fractions having different boiling points. The separated fraction containing the desired product is stripped using the vapors of a lower boiling fraction. The process of the present invention is particularly useful for recovering a desired isomer or isomer mixture from a technical mixture obtained during production of an aromatic amine such as toluenediamine. Little or no unwanted isomer or by-product is present in the isomer or isomer mixture product of this process.
摘要:
One or more fluid streams are uniformly divided into two or more partial fluid streams in chemical apparatuses in a manner such that there is a reduced tendency to form deposits. Division of such stream(s) is achieved by using a distributor device that includes at least one plate having two or more openings which openings are rounded or chamfered on at least one side.
摘要:
An isocyanate is produced by: (a) reacting chlorine with carbon monoxide to form phosgene, (b) reacting the phosgene with an organic amine to form an isocyanate and hydrogen chloride, (c) separating the isocyanate and hydrogen chloride, (d) optionally, purifying the hydrogen chloride, (e) preparing an aqueous solution of the hydrogen chloride, (f) optionally, purifying the aqueous solution of hydrogen chloride, (g) subjecting the aqueous hydrogen chloride solution to electrochemical oxidation to form chlorine, and (h) returning at least a portion of the chlorine produced in (g) to (a).
摘要:
The invention relates to a process for the production of phosgene, in which chlorine and carbon monoxide are reacted in the presence of an activated charcoal catalyst in a shell-and-tube reactor which contains a plurality of reaction tubes and a coolant space surrounding the reaction tubes, in which a) cooling of the reaction tubes is from the outside through the coolant space with water by evaporative cooling, and b) operation of the reaction tubes is at a pressure above the pressure in the coolant space.
摘要:
Aromatic amines are produced from aromatic hydrocarbons by a) reacting the aromatic hydrocarbon(s) with a mixture of nitric acid and sulfuric acid to generate a two-phase reaction mixture, b) separating the reaction mixture into an aqueous acid phase and an organic phase containing the nitroaromatic compounds c) washing the organic phase to purify the nitroaromatic compound(s), d) hydrogenating the nitroaromatic compound(s) in the presence of a catalyst to produce the aromatic amine(s) and water of reaction, and e) separating the water of reaction formed in step d) from the aromatic amine(s), in which the water of reaction separated in step e) is used to wash the organic phase containing the nitroaromatic compounds in step c).
摘要:
Polyisocyanates are produced by reacting a polyamide solution with a phosgene solution. After the product polyisocyanate has been recovered, the solvent or a portion of the solvent employed is treated with crosslinked polymers insoluble in the solvent which polymers contain primary and/or secondary alcoholic hydroxyl groups and/or primary and/or secondary amino groups. After treatment, the polymer and any reaction products are removed. The solvent may then be reused. Preferred solvents are chlorobenzene and o-dichlorobenzene. The preferred polymers are bead polymers or bead copolymers of (meth)acrylic acid or styrene/divinyl benzene copolymer.