53results about "Preparation from carbamates" patented technology

The invention relates to a preparation method and a preparation device of isocyanate, and the preparation method comprises the following steps: carrying out cold reaction on a phosgene solution and an amine solution in a cold reactor to obtain an intermediate mixed solution; separating the intermediate mixed solution by adopting a cyclone, obtaining a carbamoyl chloride mixed solution from an underflow port of the cyclone, and obtaining an amine hydrochloride mixed solution from an overflow port of the cyclone; the carbamyl chloride mixed solution enters a first thermal reactor for thermal reaction to obtain a first reaction product, and the amine hydrochloride mixed solution enters a second thermal reactor for thermal reaction to obtain a second reaction product; mixing the first reaction product and the second reaction product in a staying reactor to obtain an isocyanate reaction solution; and carrying out post-treatment on the isocyanate reaction liquid to obtain the isocyanate. The method can reduce the generation amount of urea by-products, further inhibits the generation of other subsequent by-products, reduces the chromaticity of the product, and improves the quality of isocyanate.

This application relates to a method for preparing isocyanates. Specifically, this application provides a method for preparing isocyanates by combining a supercritical phosgenation method with a piping method.

The present invention relates to the technical field of IPDI synthesis, specifically an industrializable IPDI synthesis process, comprising a synthesis process for n-butyl isophorone dicarbamate and a thermal cracking process for n-butyl isophorone dicarbamate. The synthesis process of the present invention has a simple flow, low pollution, high raw material utilization, high economic benefits, and is suitable for large-scale industrial production.

The present application relates to the technical field of IPDI synthesis, and particularly discloses a method for removing residual n-butanol in tail gas in a process for synthesizing isophorone diaminon-butyl carbamate by using a urea method, wherein the tail gas is obtained from: ammonia-containing tail gas obtained in the process for synthesizing isophorone diaminon-butyl carbamate by using the urea method, and tail gas obtained after an ammonium carbamate removal process; and the method for removing the residual n-butanol in the tail gas comprises the following steps: cooling the tail gas to 15-25 DEG C, and then adsorbing the n-butanol in the tail gas by using an adsorbent; and the adsorbent comprises molecular sieves, activated carbon and nano-polymer adsorption resin. By using the method, the content of n-butanol in the tail gas of isophorone diaminon-butyl carbamate is far lower than the industrial emission standard, no secondary pollution is caused, and the system safety is high.

The invention relates to the field of organic synthesis, in particular to a method for preparing aliphatic diisocyanate by a non-phosgene method. According to the method for preparing the aliphatic diisocyanate through the non-phosgene method, firstly, aliphatic diamine reacts with a carbonic acid diester compound to form an aliphatic dicarbamate compound, and then the aliphatic dicarbamate compound is subjected to a thermal cracking reaction to obtain the aliphatic diisocyanate. According to the method, aliphatic diamine can be converted into aliphatic diisocyanate under the condition that phosgene is not used, the preparation process is simple, a noble metal catalyst does not need to be used, the atom utilization rate is high, the product does not contain chlorine residues, the purity is high, and industrial large-scale application is facilitated.

The method for producing isocyanate compounds comprises: a step (1) for obtaining an N-substituted carbamate compound by reacting a primary amine compound and a carbonate derivative, while removing by-product compounds that have a boiling point lower than that of the N-substituted carbamate compound; a step (2) for obtaining an isocyanate compound using the reaction solution yielded by the step (1), by subjecting the N-substituted carbamate compound to thermal decomposition in the presence of an aprotic solvent and while removing the by-product hydroxy compound; a step (3) for separating the isocyanate compound and aprotic solvent from the reaction solution yielded by the step (2); and a step (4) for purifying the isocyanate compound by removing, from the fraction obtained in the step (3), component that has a boiling point higher than that of the isocyanate compound.

The invention relates to a novel method of producing 4,4'-methylene diphenyl diisocyanate (MDI). A phosgene-free method of producing 4,4'-methylene diphenyl diisocyanate is characterized in that diphenylurea is produced from urea and aniline in an aromatic hydrocarbon medium, and the resulting diphenylurea is reacted with an excess of methanol to produce O-methyl-N-phenyl carbamate; molten O-methyl-N-phenyl carbamate is reacted with anhydrous derivatives of formaldehyde in the presence of acidic catalysts to produce 4,4'-methylene diphenyl dicarbamate; 4,4'-methylene diphenyl dicarbamate in the form of a melt, or of a suspension in an inert carrier liquid, or of a powder is subjected to continuous thermal decomposition in a stream of inert gas, and 4,4'-methylene diphenyl diisocyanate is isolated by fractionation. The invention provides a novel phosgene-free method of synthesizing 4,4'-MDI, which is suitable for industrial-scale implementation.

The invention relates to organic synthesis techniques, and more particularly to a method of thermally decomposing 4,4'-methylene diphenyl dicarbamate (4,4'-MDC) to 4,4'-methylene diphenyl diisocyanate (4,4'-MDI), which is characterized in that 4,4'-MDC, in the form of a melt, or of a suspension in an inert carrier liquid, or of a powder, and an inert gas are fed into a column for conducting continuous thermal decomposition, the mixture is heated to 200-400°C inside the column for the gas-phase decomposition of 4,4'-MDC in the stream of inert gas at atmospheric pressure, then the mixture is separated in a fractionation column to isolate high-purity 4,4'-MDI. The technical result of the proposed invention is an improved method resulting in a high yield of high-purity 4,4'-MDI.

The present invention relates to a method for reducing chlorinated derivatives content in a xylylene diisocyanate (XDI) composition generated in the process of producing XDI. In particular, the present invention relates to a method for reducing chlorinated derivatives content by converting, in an apparatus for producing XDI, chlorinated derivatives into non-chlorinated derivatives by means of the metallic surface or filler, and anhydrous protic acid.

The application belongs to the technical field of fine chemical synthesis, and particularly relates to a device and method for continuously preparing 1,5-pentamethylene diisocyanate through thermal cracking. 1,5-pentamethylene diurethane and bismuth neodecanoate are mixed, preheated, and then pumped into a reaction kettle containing tetraethylene glycol dimethyl ether to perform a thermal cracking reaction. The obtained reaction liquid is subjected to primary purification, and then secondary purification is continuously performed to obtain 1,5-pentamethylene diisocyanate. The application provides a device and method for continuously preparing 1,5-pentamethylene diisocyanate through thermal cracking. The preparation process adopts a non-phosgene method, is green and environmentally friendly, has small safety hazards, has mild reaction conditions, and is simple in process. The yield of 1,5-pentamethylene diisocyanate reaches more than 80%, and the purity reaches 99%.

The invention relates to a method for preparing methyl cyclohexyl diisocyanate through liquid phase cracking of methyl cyclohexyl dicarbamate. The method comprises the following steps: dissolving methyl cyclohexyl dicarbamate in a mixture to form a raw material solution, then enabling the raw material solution and carrier gas to flow through a fixed bed reactor together, and reacting under the conditions that the vacuum degree is 0.06-0.1 MPa and the temperature is 150-300 DEG C and the liquid space velocity is 0.38-3.82 h <-1 > to obtain methyl cyclohexyl diisocyanate, the mixture is a hydrogen bond acceptor-containing ionic liquid and a solvent. The ionic liquid has the advantages of being high in catalytic activity and selectivity, good in reusability, environmentally friendly and the like.

The invention relates to a method for the preparation of isocyanates. Here it is provided that(i) a first organosilicon compound having at least one silicon atom Si1 and a unit of formula G-I bound theretois converted to a third organosilicon compound having a unit of formula G-IIby silylation of the NH group of the unit of formula G-I with a second organosilicon compound having one silicon atom Si2; and(ii) the third organosilicon compound is reacted to an isocyanate by thermolysis, whereby the unit of formula G-II is converted to an isocyanate group.

Described herein is an improved method for producing 1,5-pentamethylene diisocyanate (PDI) from cadaverine salts. The method generally involves providing a solution containing a cadaverine salt dissolved in an inert solvent in the presence of a tertiary amine base, and subjecting the solution to a liquid-phase phosgenation reaction to convert the cadaverine to PDI. The phosgenation reaction involves maintaining the reaction at a temperature of 100°C to 120°C for a time sufficient to achieve a desired threshold yield of PDI. The method described herein allows for a reduction in the amount of reactants consumed, the reaction temperature, and / or the overall reaction time compared to conventional phosgenation reactions. Because subjecting cadaverine to high temperatures can result in the formation of certain cyclic compounds that are carried over into the PDI produced, it can prove advantageous to employ biobased cadaverine salts that have not previously been subjected to distillation.

Provided is a method for producing a blocked isocyanate compound, the method comprising a reaction step of reacting a primary amine compound, a carbonic acid derivative, and a blocking agent by means of heat treatment in the presence of at least one compound selected from the group consisting of a secondary amine compound represented by general formula (I) and a tertiary amine compound represented by general formula (II) to obtain a blocked isocyanate compound. Also provided is a method for producing an isocyanate compound, the method comprising a reaction step of decomposing a blocked isocyanate compound into a blocking agent and an isocyanate compound by means of heat treatment in the presence of at least one compound selected from the group consisting of a secondary amine compound represented by general formula (I) and a tertiary amine compound represented by general formula (II) to obtain the isocyanate compound. [Chemical formula 1]

The invention relates to a process for the depolymerisation of a polyurethane material comprising the following steps: a) reacting the polyurethane material with a dialkylcarbonate or a diarylcarbonate or an alkylarylcarboante to produce i) at least one polyol and / or at least one carbonate-functionalised polyol, and ii) at least one polycarbamate; b) separating i) the at least one polyol and / or at least one carbonate-functionalised polyol, and ii) the at least one polycarbamate; and c) converting the at least one polycarbamate into at least one polyisocyanate. The resultant constituents of the depolymerised polyurethane material may subsequently be recycled for the purpose of making new polyurethanes or other useful materials.

The application provides a method and system for green preparation of hexamethylene diisocyanate, which comprises a first thermal decomposition reaction device and a second thermal decomposition reaction device connected in series, a two-component heat carrier composed of a low-boiling heat carrier and a high-boiling heat carrier, a first partial condenser and a second partial condenser. The application has the beneficial effects that: the product hexamethylene diisocyanate is prevented from staying at high temperature for too long, thereby avoiding further polymerization reaction; the by-product methanol generated in the thermal decomposition reaction is continuously carried out of the reaction system by the low-boiling carrier, thereby promoting the continuous forward progress of the thermal decomposition reaction; the isocyanate concentration is prevented from rising due to the loss of a large amount of low-boiling heat carrier, thereby preventing the side reaction from intensifying; the isocyanate concentration is effectively reduced, thereby preventing the occurrence of the polymerization side reaction.

The present invention relates to the technical field of industrial urea method for synthesizing IPDI, specifically an industrial method for continuously thermally cracking IPDU-B to produce IPDI. The industrial method includes the following continuous processes: 1) Using two thermal decomposition reactors (the first thermal decomposition reactor and the second thermal decomposition reactor), combining with distillation operation to carry out two-stage thermal decomposition reaction to prepare a reaction product containing a high IPDI content; 2) Discharging the recycled heavy components of the two-stage thermal decomposition reactors and recovering the solvent; 3) Distillation operation step: Separating the thermal decomposition product, using a two-column process of a first distillation column (light component removal column) and a second distillation column (product column), separating almost all of the n-butanol (more than 99.6% of the total amount) at the top of the first column, and taking out the crude product and the product from the side lines of the two columns respectively. The thermal cracking method provided by the present invention achieves the effects of industrial continuous production of IPDI with a yield greater than 90% and a purity greater than 99.7%.

The invention provides 1, 5-naphthalene diisocyanate and a preparation process thereof, and the 1, 5-naphthalene diisocyanate comprises the following raw materials by weight: 40-60 g of a 1, 5-naphthalene disulfonic acid derivative, 25-35 g of a nitrogen source / carbonyl precursor, 3-7 g of a phase transfer catalyst and 600-900 mL of a reaction solvent. The 1, 5-naphthalene disulfonic acid derivative provided by the invention can provide a naphthalene ring skeleton, and a sulfonic acid group can be substituted in a subsequent reaction, so that a basis is provided for constructing a 1, 5-naphthalene diisocyanate structure. The nitrogen source / carbonyl precursor is decomposed to generate amino and carbon dioxide, the amino is used as a nucleophilic reagent to be subjected to substitution reaction with a sulfonic acid group in the 1, 5-naphthalene disulfonic acid derivative, and an isocyanate group structure is constructed step by step. The long-chain alkyl group of the phase transfer catalyst has lipophilicity and can interact with an organic phase, and the quaternary ammonium cation part has hydrophilicity and can be combined with ions in a water phase, so that reactants or the catalyst in the water phase can be transferred to the organic phase in a reaction system, the reactants originally in different phases can be in full contact, and the reaction efficiency is improved. The reaction rate is greatly improved.

Disclosed in the present invention are a method for preparing a double-anion catalyst and the use thereof in the catalytic degradation of a polyurethane material. The method comprises: dissolving a metal salt in deionized water to prepare a metal salt solution; taking a nitrogen heterocyclic compound containing hydroxyl or amino as a substrate in a reactor, adding the metal salt solution in a dropwise manner into the reactor, and performing condensation reflux at 60°C-150°C for 1-8 h; adding an amine compound in a dropwise manner, reacting the mixture after the dropwise addition has finished, and performing a vacuum filtration treatment after the reaction has finished, so as to obtain a filtrate; and evaporating the filtrate and drying the product to obtain a double-anion catalyst. The basic physical properties, such as hydroxyl value, amine value and viscosity, of a recovered polyol obtained via degradation by means of the catalyst of the present invention are substantially equivalent to those of the raw material polyol, and the recovered polyol can partially replace the raw material polyol for preparing a flexible polyurethane foam.

A polyisocyanate composition containing at least one compound represented by any one of general formulae (I), (II), and (III), and a polyisocyanate compound. A method for producing an isocyanate compound, which comprises a reaction step for obtaining an isocyanate compound by decomposing a blocked isocyanate compound into a blocking agent and an isocyanate compound by heat-treating the blocked isocyanate compound in the presence of a compound having a structure represented by general formula (I) and / or general formula (II).

To provide a method for producing an isocyanate compound capable of improving the thermal decomposition rate of a blocked isocyanate compound without accompanying an increase in the amount of by-products formed.SOLUTION: A method for producing an isocyanate compound comprises a reaction step in which a blocked isocyanate compound is thermally treated in the presence of a compound having a structure represented by the general formula (I) in the figure, to decompose the blocked isocyanate compound into a blocking agent and an isocyanate compound, thereby obtaining the isocyanate compound. (In the general formula (I), R1 and R2 each independently represent a monovalent organic group.)SELECTED DRAWING: None

The invention provides a method and a device for preparing isocyanate through thermal cracking of carbamate. The device comprises a reaction system and a separation system, and the reactor comprises four areas, namely a gas distribution area, a reaction and pre-separation area, a pyrolytic reaction area and a gas-solid separation area from bottom to top in sequence. The invention also provides a method for preparing isocyanate by adopting the device for thermal cracking. By adopting the reaction device, the reaction temperature of thermal decomposition of carbamate can be effectively reduced, the side reaction is reduced, the reaction yield is improved, the problems of coking and blockage caused by high-temperature polymerization of byproducts are reduced, and the operation period is prolonged.

To provide a method for producing an isocyanate compound capable of improving the thermal decomposition rate of a blocked isocyanate compound without accompanying an increase in the amount of by-products formed.SOLUTION: A method for producing an isocyanate compound comprises a reaction step in which a blocked isocyanate compound is thermally treated in the presence of a compound having a structure represented by the general formula (I) in the figure, to decompose the blocked isocyanate compound into a blocking agent and an isocyanate compound, thereby obtaining the isocyanate compound. (In the general formula (I), R1 and R2 each independently represent a monovalent organic group, or may independently form a ring structure through a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond, provided that at least one of R1 and R2 has an aromatic group.)SELECTED DRAWING: None

The present invention provides a method for increasing the yield of isocyanate and a method for preparing isocyanate, which employs the method of the present invention to prepare isocyanate of general formula (II) to help increase the yield of the product. The method controls the acid content of an isocyanate intermediate having general formula (I) to be > 0 and < 3000 ppm, and thermally cracks the isocyanate intermediate to obtain the isocyanate; the acid content refers to the ability to release H + of the compound.

Provided is a method for producing an isocyanate compound, including a step (1) of reacting a primary amine compound with a carbonic acid derivative to obtain an N-substituted carbamate compound while extracting a by-product compound having a boiling point lower than a boiling point of the N-substituted carbamate compound, a step (2) of performing thermal decomposition of the N-substituted carbamate compound on a reaction solution obtained in the step (1) in the presence of an aprotic solvent to obtain an isocyanate compound while extracting a by-product hydroxy compound, a step (3) of separating the isocyanate compound and the aprotic solvent from a reaction solution obtained in the step (2), and a step (4) of removing a component having a boiling point higher than a boiling point of the isocyanate compound from a fraction obtained in the step (3) to purify the isocyanate compound.

The invention discloses an oxide-type catalyst for preparing aliphatic isocyanate by catalytic pyrolysis. The catalyst uses Zn(NO3)2·6H2O and 2-methylimidazole as raw materials to prepare a ZIF-8 imidazole zeolite framework; and then uses a metal nitrate M(NO3)2 as raw materials to prepare aliphatic isocyanate by an impregnation method. x ·yH2O makes metal ions M x+ Replacement of part of Zn in the ZIF‑8 imidazole zeolite framework 2+ , and obtain an M‑ZIF‑8 precursor; the M‑ZIF‑8 precursor is calcined at 400-600°C for 1-10h in an air atmosphere to obtain MO z / ZnO oxide type nanocatalyst. The catalyst of the present invention inherits the nano morphology and porous structure of the organic metal framework precursor, has a rich oxygen vacancy concentration, is conducive to mass transfer and heat transfer, and increases the utilization rate of active sites. The catalyst of the present invention has high catalytic activity, has a significant promoting effect on the catalytic pyrolysis of ADU to prepare ADI, and has high reaction activity and selectivity.

Provided is a method for producing a blocked isocyanate compound, the method comprising a reaction step of reacting a primary amine compound, a carbonic acid derivative and a blocking agent by means of heat treatment in the presence of at least one compound selected from the group consisting of a secondary amine compound of general formula (I) and a tertiary amine compound of general formula (II) to obtain a blocked isocyanate compound. Also provided is a method for producing an isocyanate compound, the method comprising a reaction step of decomposing a blocked isocyanate compound into a blocking agent and an isocyanate compound by means of heat treatment in the presence of at least one compound selected from the group consisting of a secondary amine compound of general formula (I) and a tertiary amine compound of general formula (II) to obtain the isocyanate compound.

A preparation method of a dual-anion catalyst, and a use of the dual-anion catalyst in catalytic degradation of a polyurethane material are provided. The preparation method includes: dissolving a metal salt in deionized water to produce a metal salt solution; adding a nitrogen-containing heterocyclic compound with hydroxyl or amino as a substrate to a reactor, adding the metal salt solution dropwise to the reactor, and conducting condensation reflux at 60° C. to 150° C. for 1 h to 8 h; adding an amine compound dropwise, and conducting a reaction; after the reaction is completed, conducting vacuum filtration to produce a filtrate; and subjecting the filtrate to evaporation, and oven-drying a resulting product to produce the dual-anion catalyst. A recovered polyol obtained through the degradation with the catalyst exhibits basically the same fundamental physical properties such as hydroxyl value, amine value, and viscosity to a virgin polyol.

The invention relates to a method for decomposing polyurethane, wherein material containing polyurethane is heated to a temperature from 190° C. to 250° C. under overpressure in the presence of an aqueous solution containing 1 to 45 mass percent urea. It further relates to a liquid process medium obtainable thereby.