322results about "Isocyanic acid derivatives purification/separation" patented technology

Process for the purification of toluenediisocyanate from a crude distillation feed comprising toluenediisocyanate, an organic solvent and less than 2% by weight phosgene by separating the crude distillation feed in a dividing-wall distillation column into at least four product fractions P1-P4. P1 is a phosgene enriched low-boiler product, P2 is a solvent-enriched product, P3 is a high boiler enriched bottoms and P4 is a toluenediisocyanate product stream.

A mixture of isomeric diisocyanatodiphenylmethanes composed of at least 2,2′-diisocyanato-diphenylmethane, 2,4′-diisocyanatodiphenylmethane and 4,4′-diisocyanatodiphenyl-methane is distilled in at least one stage and a divided-wall column is used in at least one distillation stage.

The invention discloses a preparation method of hydrogenated xylylene diisocynate. The preparation method of the hydrogenated xylylene diisocynate comprises the following steps: (1) performing salt forming reaction on 1,3-cyclohexanol dimethylamine and concentrated hydrochloric acid in a two-phase reaction solvent to obtain amine salt, wherein the two-phase reaction solvent consists of water and an inert organic solvent insoluble in water ; (2) performing photochemical reaction on the ammonium salt obtained in the step (1) and phosgene in an inert solvent by taking N,N-dimethylformamide or N,N-dimethylacetamide as a catalyst to obtain reaction liquid, and performing aftertreatment on the reaction liquid to obtain the hydrogenated xylylene diisocynate. The preparation method of the hydrogenated xylylene diisocynate has the advantages of complete ammonium salt formation, small grain size of the ammonium salt, low viscosity of the ammonium salt, high space-time conversion rate of photochemical reaction, simple process, low cost and the like.

The disclosure features novel lipids and compositions involving the same. Nanoparticle compositions include a novel lipid as well as additional lipids such as phospholipids, structural lipids, and PEG lipids. Nanoparticle compositions further including therapeutic and / or prophylactics such as RNA are useful in the delivery of therapeutic and / or prophylactics to mammalian cells or organs to, for example, regulate polypeptide, protein, or gene expression.

Isocyanates are produced by reacting an organic amine with phosgene in process which includes at least three stages. The first stage is carried out in a dynamic mixer. The second stage is carried out in at least one reactor. The third stage is carried out in at least one material separating apparatus. The pressure in the reactor of the second stage must be greater than or equal to the pressure in the dynamic mixer. The pressure in the third stage material separating apparatus must be lower than the pressure in the second stage reactor.

This invention relates to a method for distilling an isomer mixture of isocyanate. The method comprises: adding an isomer mixture of diphenylmethane diisocyanate into a separator, and distilling to obtain at least one product mixture, which comprises: 2,4'-MDI 50-60 wt.%, 4,4'-MDI 40-50 wt.%, 2,2'-MDI less than 1.5 wt.%, 2,4'-MDI less than 1 wt.%, and 4,4'-MDI greater than 99 wt.%. Compared with present distillation methods, the method has such advantages as saved distillation steps, reduced distillation column number, saved energy input, reduced isocyanate loss, and high 4,4'-MDI purity in the product mixture.

The disclosure features novel lipids and compositions involving the same. Nanoparticle compositions include a novel lipid as well as additional lipids such as phospholipids, structural lipids, and PEG lipids. Nanoparticle compositions further including therapeutic and / or prophylactics such as RNA are useful in the delivery of therapeutic and / or prophylactics to mammalian cells or organs to, for example, regulate polypeptide, protein, or gene expression.

The invention relates to a method for synthesizing hexamethylene diisocyanate (HDI) biuret through a spray method. The method comprises the following steps: adopting the high pressure to inject water in the form of fog drops into an HDI contained reaction kettle, setting the temperature to be between 60 and 130 DEG C, setting the mol ratio of HDI to water 2 to 15, setting the water spraying time to be between 0.5 and 8 hours, carrying out heat preservation at a temperature of between 80 and 150 DEG C for 0 to 5 hours, and then carrying out the separation through a separating device; setting the separation temperature to be between 70 and 200 DEG C and the pressure to be between 0.5 and 50,000Pa; and pumping the separated steaming residue into a dilution container with a stirrer for dissolution, adding a metered solvent into the dilution container in advance, continuously adding the metered solvent into the dilution container with the pumping of the steaming residue, and carrying out the dilution to obtain an HDI biuret product with 25 to 100 percent of solid content. The method improves the reaction efficiency for producing the HDI biuret product, reduces the generation of polyurea, reduces the HDI content in the HDI biuret, and reduces the use toxicity of the HDI biuret. In addition, the production process is economical and has environmental protection.

An isocyanate is produced by reacting a primary amine with phosgene in the gas phase above the boiling point of the amine over an average contact time of 0.05 to 15 seconds under adiabatic conditions.

The present invention relates to a process for the production of 4,4′-diphenylmethane diisocyanate (4,4′-MDI) by acid-catalyzed condensation of aniline with formaldehyde, reaction of the mixtures of di- and polyamines obtained with phosgene to form the corresponding mixture of MDI isomers and homologues (di- and polyisocyanates of the diphenylmethane series) and subsequent separation of the mixture by distillation to form 4,4′-MDI and polymeric MDI.

The invention relates to a refining and reclaiming technology of a tail gas absorption solvent in the production of toluene diisocyanate (TDI). The solvent containing little phosgene, toluene diisocyanate and di-Et-1,3-benzenedicarboxylate (DEIP) performs two-stage refinement in an atmospheric refining tower and a vacuum refining tower, and a falling-film evaporator and a storage tank are arranged between the two towers. The overhead non-condensable gas phase of the atmospheric refining tower is returned to a phosgene absorption tower to recycle phosgene, the refined solvent is drawn from theside of the atmospheric refining tower, the temperature of the tower bottom is controlled to be 3-8 DEG C higher than the boiling point of the solvent, the discharged material of the tower bottom enters the falling-film evaporator, the evaporating temperature is 20-30 DEG C higher than the boiling point of the solvent, the unevaporated material enters the storage tank for storage, the material inthe storage tank performs batch vacuum rectification under the absolute pressure of 0.1-0.25bar, and the unevaporated residual material enters the residue evaporator of a TDI device to recycle TDI and DEIP. By using the solvent refining technology provided by the invention, the useful components in the solvent can be completely recycled, and the technology has the advantages of simple and stable operation and lower cost and energy consumption.

The invention relates to a method for preparing crude 1,6-hexamethylene diisocyanate through the phosgene method and separating pure 1,6-hexamethylene diisocyanate through rectification. The method uses o-dichlorobenzene and chlorobenzene as solvents and comprises the following steps: using hexanediamine and excessive phosgene to perform the two-step reaction of low temperature photochemical reaction and high temperature photochemical reaction under the action of catalyst and generate 1,6-hexamethylene diisocyanate (HDI), removing o-dichlorobenzene through distillation for reuse, continuously distilling to remove by-product chlorinated isocyanate, further mixing with DEIP solvent in a certain ratio through compulsory stirring, heating to perform flash evaporation and rectification, preparing the 1,6-hexamethylene diisocyanate product and DEIP through separation and purification, and regularly discharging the slagged tarry macromolecular compound to perform burning treatment.

Isocyanates, preferably diisocyanates and polyisocyanates of the diphenylmethane series (MDI), are produced by reaction of amines dissolved in a solvent with phosgene in the same solvent to form the corresponding isocyanates. Hydrogen chloride and excess phosgene are subsequently removed from the reaction mixture to obtain a crude isocyanate-containing solution. Subsequently, the crude isocyanate-containing solution is separated by distillation into isocyanates and solvent. The solvent is recycled and used for the production of solutions of the amines and of phosgene. The solvent being recycled is treated to reduce the phosgene and diisocyanate contents before being used for the production of the solution of the amine.

The present invention relates to a process for the preparation of isocyanates by reacting the appropriate amines with phosgene, condensing the gas mixture thereby obtained, stripping the liquid phase thereby obtained and returning the solvent so retained in liquid form to the reaction stage. The gaseous constituents are then purified further in an absorption process.

Isocyanates are produced by reaction of primary amines with phosgene in the gas phase. In this process, the reaction is terminated by guiding the reaction mixture from the reaction chamber through a cooling stretch into which liquids are injected. Direct cooling takes place in the cooling stretch in one stage in two or more cooling zones connected in series.

Processes are described which comprise: (a) reacting chlorine with carbon monoxide to form phosgene; (b) reacting the phosgene with at least one organic amine to form at least one isocyanate and hydrogen chloride; (c) separating the hydrogen chloride; (d) oxidizing the hydrogen chloride with oxygen in a gas phase to form additional chlorine; and (e) recycling at least a portion of the additional chlorine to the reaction of the chlorine and the carbon monoxide; wherein the oxidation of the hydrogen chloride is initiated via a high energy source which may be selected from electron-exciting radiation, ionizing radiation, a gas discharge, a plasma, and combinations thereof.

Isocyanates are produced by a) reacting at least one amine with phosgene, optionally in the presence of a solvent to produce the corresponding isocyanate and a stream containing hydrogen chloride, phosgene and optionally solvent, low-boiling compounds and inert substances is obtained, b) separating the stream containing hydrogen chloride, phosgene and optionally solvent, low-boiling compounds and inert substances in an at least two-stage sequence of absorption steps that includes (1) at least one isothermal absorption step and (2) at least one adiabatic absorption step, to obtain (i) a hydrogen chloride stream containing phosgene in concentrations of at most 0.5 wt. % (based on the weight of the hydrogen chloride stream) and (ii) a liquid phosgene stream, and c) recycling the liquid phosgene stream (ii) to the reaction of amine with phosgene.

Toluene diisocyanate is recovered from a crude distillation feed containing less than 2% by weight of phosgene by(a) fractionating the crude distillation feed containing less than 2% by weight of phosgene to remove the solvent and optionally the reaction residues to produce a crude toluene diisocyanate feed containing less than 20% by weight of solvent and(b) separating the crude toluene diisocyanate feed containing less than 20% by weight of solvent in a divided-wall distillation column into four product fractions P1–P4. P1 is a vapor phase low-boiler and solvent-enriched gas stream, P2 is a low-boiler and solvent-enriched product, P3 is a high boiler-enriched bottoms product containing toluene diisocyanate and P4 is a toluene diisocyanate product stream lean in low-boilers, high-boilers and reaction residues.

A fraction of diisocyanates of the diphenylmethane series containing at least 95 wt. % binuclear methylenediphenyl diisocyanate is obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to produce diamines and polyamines of the diphenylmethane series containing binuclear methylenediphenyl diamine, b) phosgenating the diamines and polyamines produced in a), optionally in the presence of a solvent, to produce a crude diisocyanate and polyisocyanate, and c) separating a fraction containing at least 95 wt. % binuclear methylenediphenyl diisocyanate with a 4,4′-MDI content of over 60 wt. %, a 2,4′-MDI content of 4 to 35 wt. % and a 2,2′-MDI content of 0.01 to 10 wt. %, relative to the mass of the fraction, and a maximum of 20 ppm phenyl isocyanate and optionally a maximum of 50 ppm solvent from the crude diisocyanate and polyisocyanate produced in b) in a single distillation step with optional upstream and / or downstream separation of low-boiling components.

The invention provides a process for producing a variety renewable aromatic compounds such as benzene, toluene, xylenes, and cumene, as well as compounds derived from these including, for example, aniline, benzoic acid, cresol, cyclohexane, cyclohexanone, phenol and bisphenol A, toluene di-isocyanate, isophthalic acid, phthalic anhydride, terephthalic acid and dimethyl terephthalate. The invention also provides for renewable forms of these aromatic compounds.

The invention specifically relates to production equipment for refining hexamethylene diisocyanate and a method thereof. A stirrer is respectively arranged in the middle of the bottom of both a distillation column and a rectifying tower which are provided with a stirring device, and stirring wings are a frame type. The method for refining hexamethylene diisocyanate comprises the following steps: (1) letting an synthesized HDI solution enter a distillation column through a heat exchanger, starting a first vacuum pump, and starting a first stirrer in the column bottom while the agitation speed is less than or equal to 60rpm / min; Starting a first condenser on the tower top, evaporating all o-dichlorobenzene, continuously discharging by the distillation column and entering a mixing tank; and (ii) adding a DEIP solvent into the mixing tank, uniformly mixing crude HDI and the DEIP solvent according to the HDI-DEIP ratio of 1:1-1.5, sending the mixture into the rectifying tower to firstly evaporate mono-isocyanate chloride and continuously evaporate the HDI, drawing forth the DEIP for recycling, stirring high polymer residue in a heating vessel and discharging regularly, and carrying out burning treatment. The device and method provided by the invention can be applied in distillation separation and purification production technology which is easy to generate auto-agglutination phenomenon under the distillation condition.

The invention discloses a method for recovering heat integrated solvent in the continuous production of toluene di-isocyanate, comprising the following steps: respectively importing materials to be distilled, which contains the toluene di-isocyanate and an inert organic solvent, to a first solvent eliminating tower with higher operation pressure and a second solvent eliminating tower with lower operation pressure to carry out distillation; leading steam from the top of the first solvent eliminating tower into a first condenser and leading part of tower bottom liquid in the second solvent eliminating tower into the first condenser to carry out heat transferring; and leading part of the tower bottom liquid from the first solvent eliminating tower and the second solvent eliminating tower intoa third solvent eliminating tower to carry out distillation. The method can obviously reduce the energy consumption in the production of the toluene di-isocyanate, thereby reducing the production cost of a unit toluene di-isocyanate product.

Cycloaliphatic diisocyanates can be prepared continuously and phosgene-free by reacting at least one cycloaliphatic diamine with at least one carbonic acid derivative and at least one alcohol to give a cycloaliphatic diurethane; freeing the cycloaliphatic diurethane of a low boiler, a medium boiler and mixtures thereof; thermally cleaving the cycloaliphatic diurethane in a cleavage apparatus to give a cycloaliphatic diisocyanate and a cleavage residue; continuously discharging a portion of the cleavage residue from the cleavage apparatus; removing the high boiler components from the discharge to obtain a purified discharge; reurethanizing the purified discharge with alcohol to obtain a reurethanized discharge; and recycling the reurethanized discharge into the process.

Isocyanates are produced by reaction of primary amines with phosgene in the gas phase. In this process, the reaction is terminated by guiding the reaction mixture from the reaction chamber through a cooling stretch into which liquids are injected. Direct cooling takes place in the cooling stretch in one stage in two or more cooling zones connected in series.

The present invention relates to a process for the production of MDI fractions containing 2,4′-MDI, and in which the 2,2′-MDI component from the MDA production is largely removed from the isomer mixture. Highly reactive monomeric MDI products can be produced in this way. These MDI products are characterised in their processing by significantly reduced emissions of MDI monomers.