CN115043758B

CN115043758B - Method for preparing isocyanate by combining supercritical phosgenation method and pipelining method

Info

Publication number: CN115043758B
Application number: CN202210797409.5A
Authority: CN
Inventors: 薛永和; 陆成樑; 刘文杰; 袁海新; 刘佳特; 邱贵森
Original assignee: Mojia Shanghai Biotechnology Co ltd
Current assignee: Mojia Shanghai Biotechnology Co ltd
Priority date: 2022-07-06
Filing date: 2022-07-06
Publication date: 2023-10-27
Anticipated expiration: 2042-07-06
Also published as: CN115043758A

Abstract

The application relates to a method for producing isocyanates. In particular, the application provides a method for preparing isocyanate by combining a supercritical phosgenation method with a pipelining method.

Description

Method for preparing isocyanate by combining supercritical phosgenation method and pipelining method

Technical Field

The present application relates to a method for preparing isocyanate, and more particularly, to a method for preparing isocyanate by combining a supercritical phosgenation method with a pipelining method.

Background

Isocyanates are a class of compounds containing one or more isocyanate groups. Including aliphatic isocyanates, aromatic isocyanates, unsaturated isocyanates, halogenated isocyanates, thioisocyanates, phosphorous-containing isocyanates, inorganic isocyanates, blocked isocyanates, and the like. Because the polyurethane has highly unsaturated isocyanate groups, the polyurethane has high chemical activity and can generate important chemical reaction with various substances, so the polyurethane can be widely applied to the fields of polyurethane, polyurethane urea and polyurea, polymer modification, organic synthesis reagents, agriculture, medicine and the like.

The principle of preparing isocyanates using phosgene and amines is well known in the prior art. Due to the high reactivity of amines, especially aliphatic diamines, the amine which is not reacted temporarily may react with the reaction products and intermediates during the phosgenation reaction, thereby producing by-products, e.g. amine hydrochlorides, urea, condensed Biurea, and the like. To avoid the formation of by-products, a capping reagent (e.g., HCl) may be selected to cap the amine group (-NH) of the amine ₂ ) Protecting to form amine salt. However, amine salts are much less reactive than free amines and are practically insoluble in any common organic solvent and can only be dispersed in the solvent. It has been proved that the phosgenation reaction using amine salts as raw materials generally requires the use of a large amount of solvent as a dispersant, and the content of amine salts in the solvent is often less than 10%, and the residence time of the phosgenation reaction is often several hours or even tens of hours.

Thus, there remains a need for an optimized isocyanate preparation process.

Disclosure of Invention

The object of the present application is to provide a process for preparing isocyanates, more particularly for preparing isocyanates by the supercritical phosgenation process in combination with the pipelining process.

In one aspect, the present application provides a process for preparing isocyanates, characterized in that it comprises the steps of:

(a) Mixing the reactant amine stream and the phosgene stream at a temperature of-5 to 5 ℃ to obtain a mixture of reactant amine and phosgene;

(b) Regulating the temperature of the mixture obtained in the step (a) to 182-205 ℃ so that the phosgene is in a supercritical state, and carrying out reaction in a supercritical reactor for at least 15 minutes;

(c) Allowing the reaction product mixture obtained in step (b) to react under reduced pressure for a reaction time of not more than 30 seconds.

In certain embodiments, the depressurizing in step (c) is performed in a depressurizer. For example, step (c) is to introduce the reaction product mixture in the supercritical reactor of step (b) into a reduced pressure reactor for reaction.

In certain embodiments, the method further comprises step (d) collecting the product. In certain embodiments, step (d) comprises: providing a quench zone at the outlet of the depressurization reactor such that the reaction product mixture obtained in step (c) is contacted with a quench medium stream passing into the quench zone to reduce the temperature of the reaction product mixture obtained in step (c) to below 170 ℃.

In certain embodiments, the method further comprises step (e) purifying the product. In certain embodiments, the step (e) comprises:

1) Introducing the reaction product mixture obtained in the step (c) or the step (d) into a degassing tower, wherein hydrogen chloride and phosgene in the reaction product mixture overflow from the top of the degassing tower and enter a hydrogen chloride/phosgene separation tower, and the hydrogen chloride overflowed from the top of the separation tower is refined by a tail gas removal treatment unit to form hydrochloric acid as a byproduct;

2) Recycling phosgene from the bottom of the separation column of sub-step 1) to form the phosgene stream of step (a);

3) Collecting isocyanate and byproducts from the bottom of the degasser of sub-step 1) in the reaction product mixture, passing them through a lights removal column to remove lights byproducts;

4) Collecting isocyanate and heavy component byproducts from the bottom of the light component removal column of sub-step 3), passing them through a refining column, collecting isocyanate from the refining column, and removing heavy component byproducts.

In certain embodiments, the light component byproducts in sub-step 3) above are selected from the group consisting of: piperidine, polyhydropyridine, and combinations thereof. In certain embodiments, the heavy component by-product in sub-step 4) above is selected from the group consisting of: tar, PDI polymer, byproduct urea, and any combination thereof.

In certain embodiments, step (a) is performed before step (b) and step (c).

In certain embodiments, no organic solvent is used in step (a), step (b) and step (c).

In certain embodiments, in step (a), the reactant amine stream and the phosgene stream are mixed in a supercritical reactor.

In certain embodiments, the reactant amine stream and the phosgene stream are mixed and then shear emulsified to form suspended particles. In certain embodiments, the shear emulsification is performed in a supercritical reactor.

In certain embodiments, the suspended particles have a diameter of less than or equal to 100 μm. In certain embodiments, the suspended particles have a diameter of less than or equal to 50 μm. In certain embodiments, the suspended particles have a diameter of less than or equal to 20 μm.

In certain embodiments, in step (a), the reactant amine stream and the phosgene stream are sheared and emulsified uniformly by a homogenizing pump. In certain embodiments, the shear emulsification uniformity is achieved by controlling the lift, rotational speed, torque, suction, and/or shear homogenization time of the homogenizing pump. In certain embodiments, the circulating output volume of the homogenizing pump is controlled to be greater than or equal to 10 times the volume of the liquid holdup in the supercritical reactor.

In certain embodiments, the phosgene stream in step (a) is in stoichiometric excess based on the amino groups of the reactant amine stream.

In certain embodiments, the ratio of the phosgene stream to the reactant amine stream feed (on a molar basis) in step (a) is from 7:1 to 25:1. In certain embodiments, the ratio of the phosgene stream to the reactant amine stream feed (on a molar basis) in step (a) is from 10:1 to 20:1. In certain embodiments, the phosgene stream and reactant amine stream in step (a) are fed in a ratio (on a molar basis) of 12:1.

In certain embodiments, the phosgene stream in step (a) is present in liquid form.

In certain embodiments, the reaction temperature of step (c) is 150 ℃ to 450 ℃. In certain embodiments, the reaction temperature of step (c) is from 200 ℃ to 400 ℃. In certain embodiments, the reaction temperature of step (c) is from 250 ℃ to 350 ℃.

In certain embodiments, the reaction pressure of step (c) is from 15KPa to 500KPa. In certain embodiments, the reaction pressure of step (c) is from 50KPa to 300KPa. In certain embodiments, the reaction pressure of step (c) is from 50KPa to 110KPa. In certain embodiments, the reaction pressure of step (c) is from 80KPa to 100KPa.

In certain embodiments, the reaction residence time of step (c) is from 0.5 seconds to 30 seconds. In certain embodiments, the reaction residence time of step (c) is from 1.5 seconds to 20 seconds. In certain embodiments, the reaction residence time of step (c) is from 2.5 seconds to 10 seconds.

In certain embodiments, the product collection temperature of step (d) is 170 ℃ or less. In certain embodiments, the product collection temperature of step (d) is from 80 ℃ to 150 ℃. In certain embodiments, the product collection temperature of step (d) is from 110 ℃ to 140 ℃.

In certain embodiments, in step (d), the latent heat of vaporization of the quenching medium is utilized to rapidly reduce the temperature of the reaction product mixture obtained in step (c). In certain embodiments, the quenching medium described in step (d) is selected from the group consisting of: an organic solvent, isocyanate, phosgene, hydrogen chloride, an inert carrier gas, and any combination thereof. In certain embodiments, the organic solvent is selected from the group consisting of: dichloromethane, chlorobenzene, o-dichlorobenzene, benzene, toluene, xylene, hexane, tetrahydrofuran, chloronaphthalene, and any combination thereof. In certain embodiments, the quenching medium described in step (d) is in a liquid state. In certain embodiments, the quenching medium described in step (d) is liquid phosgene.

In certain embodiments, the depressurization reactor is a pipeline reactor. In certain embodiments, the reduced pressure reactor has a conduit inner diameter of 4 to 9mm.

In certain embodiments, the isocyanate is a diisocyanate. In certain embodiments, the isocyanate is an aliphatic diisocyanate or an aromatic diisocyanate. In certain embodiments, the isocyanate is selected from the group consisting of: diphenylmethylene diisocyanate as pure isomer or as a mixture of isomers, toluene diisocyanate as pure isomer or as a mixture of isomers, 2, 6-xylene isocyanate, 1, 5-naphthalene diisocyanate, methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, isobutyl isocyanate, t-butyl isocyanate, pentyl isocyanate (e.g., pentanediol diisocyanate), t-pentyl isocyanate, isopentyl isocyanate, neopentyl isocyanate, hexyl isocyanate (e.g., hexanediisocyanate), cyclopentyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate (e.g., p-phenylene diisocyanate).

In certain embodiments, the isocyanate is Pentamethylene Diisocyanate (PDI), hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), or methylcyclohexane diisocyanate (HTDI). In certain embodiments, the reactant amine has the formula R (NH ₂ ) _n Wherein n is 1, 2 or 3, and R is an aliphatic or aromatic hydrocarbon group. In certain embodiments, n is 2 and R is an aliphatic hydrocarbon group. In certain embodiments, n is 2 and R is an aliphatic hydrocarbon group having 2 to 10 carbon atoms. In certain embodiments, n is 2 and R is a linear or cyclic aliphatic hydrocarbon group having 3 to 10 carbon atoms.

In certain embodiments, the reactant amine is present in free form.

In certain embodiments, the reactant amine is present in the form of an amine salt. In certain embodiments, the amine salt is selected from the group consisting of: hydrochloride, sulfate, bisulfate, nitrate and carbonate.

In certain embodiments, the reactant amine is selected from one or more of the following groups: ethylamine, butylamine, pentylene diamine, hexamethylenediamine, 1, 4-diaminobutane, 1, 8-diaminooctane, aniline, p-phenylenediamine, m-xylylenediamine, toluenediamine, 1, 5-naphthalenediamine, diphenylmethane diamine, dicyclohexylmethane diamine, m-cyclohexyldimethylene diamine, isophorone diamine, methylcyclohexane diamine, trans-1, 4-cyclohexanediamine.

In certain embodiments, the reactant amine is selected from the group consisting of: PDA, PDA hydrochloride, HDA hydrochloride, IPDA hydrochloride, HTDA and HTDA hydrochloride.

Drawings

The above and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. It is appreciated that these drawings depict only several embodiments of the present disclosure and are therefore not to be considered limiting of its scope. The present application will be described more specifically and in detail with reference to the accompanying drawings.

FIG. 1 shows a schematic flow diagram of a process for preparing isocyanates according to one embodiment of the present application; wherein: 01 is a supercritical reactor, 02 is a decompression reactor, 03 is a quenching device, 04 is a degassing tower, 05 is a phosgene/hydrogen chloride separation tower, 06 is a light component removal tower, and 07 is a product refining tower.

Detailed Description

The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the inventive subject matter. It will be readily understood that the aspects of the present disclosure, as generally described and illustrated in the figures herein, could be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated as part of this disclosure.

In one aspect, the present application provides a process for preparing an isocyanate, the process comprising the steps of:

In the present application, "isocyanate" refers to a class of compounds containing one or more (e.g., two, three, four, five, six, seven, eight, nine, ten or more) isocyanate groups (R-n=c=o), including aliphatic isocyanates, aromatic isocyanates, unsaturated isocyanates, halogenated isocyanates, thioisocyanates, phosphorous-containing isocyanates, inorganic isocyanates, blocked isocyanates, and the like. In certain embodiments, the isocyanate in the present application is a diisocyanate. In certain embodiments, the isocyanate in the present application is an aliphatic diisocyanate or an aromatic diisocyanate. In certain embodiments, the isocyanates in the present application include aromatic isocyanates, aliphatic isocyanates, for example, aromatic isocyanates include diphenylmethylene diisocyanate as a pure isomer or as a mixture of isomers, toluene diisocyanate as a pure isomer or mixture of isomers, 2, 6-xylene isocyanate, 1, 5-naphthalene diisocyanate, and the like. Aliphatic isocyanates include methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, isobutyl isocyanate, t-butyl isocyanate, pentyl isocyanate, t-pentyl isocyanate, isopentyl isocyanate, neopentyl isocyanate, hexyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, and the like. In certain embodiments, the isocyanate in the present application is selected from the group consisting of: pentanediisocyanate, hexanediisocyanate, p-phenylene diisocyanate, toluene diisocyanate. In certain embodiments, the isocyanate in the present application is Pentamethylene Diisocyanate (PDI), hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), or methylcyclohexane diisocyanate (HTDI).

The steps (a), (b) and (c), and optionally the steps (d) and (e), respectively, of the process for preparing isocyanates according to the present application are described in detail below.

1.Step (a)

In step (a) of the present application, the reactant amine stream and the phosgene stream are mixed at a temperature of from-5 to 5 ℃ to obtain a mixture of reactant amine and phosgene.

In the present application, "reactant amine" means that the starting material for preparing isocyanate contains amino (-NH) ₂ ) A compound of a group. For example, in certain embodiments, the reactionThe structural formula of the amine is R (NH) ₂ ) _n Wherein n is 1, 2 or 3, and R is an aliphatic or aromatic hydrocarbon group. In certain embodiments, n is 2 and R is an aliphatic hydrocarbon group. In certain embodiments, n is 2 and R is an aliphatic, cycloaliphatic, or aromatic hydrocarbon group having 2-10 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10 carbon atoms). In certain embodiments, n is 2 and R is a linear or cyclic aliphatic hydrocarbon group having 3-10 carbon atoms (e.g., 3, 4, 5, 6, 7, 8, 9, 10 carbon atoms).

In certain embodiments, the reactant amine is a primary amine, i.e., contains NH ₂ A group. In certain embodiments, the reactant amine is a diamine, i.e., contains 2 NH' s ₂ A group. In certain embodiments, the reactant amine is selected from one or more of the following groups: ethylamine, butylamine, pentylene diamine, hexamethylenediamine, 1, 4-diaminobutane, 1, 8-diaminooctane, aniline, p-phenylenediamine, m-xylylenediamine, toluenediamine, 1, 5-naphthalenediamine, diphenylmethane diamine, dicyclohexylmethane diamine, m-cyclohexyldimethylene diamine, isophorone diamine, methylcyclohexane diamine, trans-1, 4-cyclohexanediamine. In certain embodiments, the reactant amine is selected from one or more of the following groups: pentanediamine (e.g., 1, 5-dipentylamine), hexamethylenediamine (e.g., 1, 6-hexamethylenediamine), p-phenylenediamine, isophoronediamine, methylcyclohexamethylenediamine, toluenediamine. In certain embodiments, the reactant amine is Pentylene Diamine (PDA).

In certain embodiments, the reactant amine is present in free form. The term "free" refers to the amine compound in a non-salt form. Amine compounds in the free form may differ from their various salt forms in certain physical and/or chemical properties, for example, solubility in polar solvents. The amine compounds in the free form may also be the same or similar in certain physical and/or chemical properties as their various salt forms.

In certain embodiments, the reactant amine is selected from one or more of the following groups: pentanediamine (PDA), PDA hydrochloride, hexamethylenediamine (HDA), HDA hydrochloride, isophorone diamine (IPDA), IPDA hydrochloride, methylcyclohexamethylenediamine (HTDA) and HTDA hydrochloride.

In conventional methods of preparing isocyanates, organic solvents are typically used to disperse the reactant amine, or inert carrier gases (e.g., nitrogen, carbon dioxide, carbon monoxide, helium, or argon) are used to assist in the vaporization of the reactant amine and to achieve a more suitable dispersing effect. However, in the present invention, the inventors have unexpectedly found that the mixing of reactant amine and phosgene in step (a) may be accomplished without the use of an organic solvent and without the use of an inert carrier gas. In certain embodiments, the mixing of the reactant amine stream and the phosgene stream occurs in a supercritical reactor (e.g., both are introduced into the supercritical reactor for mixing). In certain embodiments, the reactant amine stream and the phosgene stream are conducted outside of a supercritical reactor, namely: the two are introduced into the supercritical reactor after being mixed in other containers or pipelines. In order to facilitate mixing the reactant amine stream and the phosgene stream to facilitate the subsequent reaction, in step (a), the reactant amine stream and the phosgene stream may be mixed and then sheared to form suspended particles. In certain embodiments, the suspended particles have a diameter of, for example, less than or equal to 100 μm, or less than or equal to 50 μm, or less than or equal to 20 μm. In certain embodiments, the suspended particles have a diameter of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm, or a range between any two of the foregoing. Without being bound by any theory, it is believed that the smaller the diameter of the suspended particles formed, the more advantageous the subsequent reaction of the reactants amine and phosgene proceeds.

After mixing the reactant amine stream and phosgene stream in step (a), shear emulsification may be performed using any method known in the art. For example, a high-speed shearing emulsifying machine, a supergravity mixing device, a homogenizing pump, etc. can be used to uniformly shear and emulsify reactant amine and phosgene by a mechanical shearing method. In certain embodiments, the reactant amine stream and the phosgene stream are mixed and then sheared and emulsified uniformly by a homogenizing pump. In certain embodiments, the shear emulsification is performed in the supercritical reactor. The homogenizing pump used in the present application may be commercially available, for example, a DHX type homogenizing pump available from Ningbodeli pump industry Co.

The homogenizing pump may be provided inside the supercritical reactor (referred to as an "internal homogenizing pump" in this case) or outside the supercritical reactor (referred to as an "external homogenizing pump" in this case). In certain embodiments of the application, the homogenizing pump is an in-built homogenizing pump. When using an internal homogenizing pump, the skilled person may preferably achieve said shearing emulsification uniformity by controlling the lift, rotational speed, torque, suction force and/or shearing homogenizing time of said homogenizing pump, the specific values may be determined according to the size of the supercritical reactor and/or the experience of the skilled person. In certain embodiments, the rotational speed of the built-in homogenizing pump is set to be 1000 to 3000r/min (e.g., 1000r/min, 1100r/min, 1200r/min, 1300r/min, 1400r/min, 1500r/min, 1600r/min, 1700r/min, 1800r/min, 1900r/min, 2000r/min, 2100r/min, 2200r/min, 2300r/min, 2400r/min, 2500r/min, 2600r/min, 2700r/min, 2800r/min, 2900r/min, 3000r/min, or any value or range between any two of the above). In certain embodiments, the built-in homogenizing pump is provided with a flow rate of 120 to 250m ³ /h (e.g. 120m ³ /h、130m ³ /h、140m ³ /h、150m ³ /h、160m ³ /h、170m ³ /h、180m ³ /h、190m ³ /h、200m ³ /h、210m ³ /h、220m ³ /h、230m ³ /h、240m ³ /h、250m ³ /h or any value or range between any two values above). In some embodimentsThe pressure of the built-in homogenizing pump is set to be 0.1 to 1.2MPa (for example, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa, 1.1MPa, 1.2MPa or a value or a range between any two of the above). In certain embodiments, the inlet of the in-built homogenizing pump is provided at a value or range between 80mm and 110mm (e.g., 85mm, 90mm, 95mm, 96mm, 97mm, 98mm, 99mm, 100mm, 105mm, 110mm, or any two of the above). In certain embodiments, the outlet of the in-built homogenizing pump is provided as 60mm to 90mm (e.g., 65mm, 70mm, 75mm, 76mm, 77mm, 78mm, 79mm, 80mm, 81mm, 82mm, 83mm, 84mm, 85mm, 90mm, or any value or range between any two of the above).

Without being bound by any theory, it is believed that when the built-in homogenizing pump cycle output volume is n times the volume of liquid holdup in the supercritical reactor, the built-in homogenizing pump has performed at least n shear emulsions of reactant amine and phosgene therein. For example: when the circulation output volume of the built-in homogenizing pump is 10 times of the volume of the liquid holdup in the supercritical reactor, the built-in homogenizing pump has performed 10 times of shearing emulsification on reactant amine and phosgene in the built-in homogenizing pump. In certain embodiments, the determination of whether shear emulsification uniformity has been achieved is based on the built-in homogenizing pump cycle output volume being greater than or equal to 10 volumes of liquid holdup in the supercritical reactor. For example, when the built-in homogenizing pump circulation output volume is greater than or equal to 10 times the volume of the liquid holdup in the supercritical reactor (e.g., the built-in homogenizing pump circulation output volume is 11 times, 12 times, 13 times, 14 times, 15 times, 16 times, 17 times, 18 times, 19 times, 20 times, 25 times, 30 times, 35 times, 40 times, 45 times, 50 times or more the liquid holdup in the supercritical reactor), it is determined that the mixing of reactant amine and phosgene has achieved shear emulsification uniformity.

In some embodiments, the homogenizing pump is an external homogenizing pump, the homogenizing pump is arranged outside the supercritical reactor, and the sheared and emulsified mixture is directly conveyed into the supercritical reactor from the homogenizing pump. When an external homogenizing pump is used, one skilled in the art can control the external homogenizing pumpThe choice, rotation speed and residence time of the material in the homogenizing pump ensure that shearing and emulsification are uniform. In certain embodiments, the rotational speed of the external homogenizing pump is set to 1000 to 3000r/min (e.g., 1000r/min, 1100r/min, 1200r/min, 1300r/min, 1400r/min, 1500r/min, 1600r/min, 1700r/min, 1800r/min, 1900r/min, 2000r/min, 2100r/min, 2200r/min, 2300r/min, 2400r/min, 2500r/min, 2600r/min, 2700r/min, 2800r/min, 2900r/min, 3000r/min, or any value or range between any two of the above). In some embodiments, the external homogenizing pump is set to have a flow rate of 120 to 250m ³ /h (e.g. 120m ³ /h、130m ³ /h、140m ³ /h、150m ³ /h、160m ³ /h、170m ³ /h、180m ³ /h、190m ³ /h、200m ³ /h、210m ³ /h、220m ³ /h、230m ³ /h、240m ³ /h、250m ³ /h or any value or range between any two values above). In certain embodiments, the external homogenizing pump is set to a pressure of 0.1 to 1.2MPa (e.g., 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa, 1.1MPa, 1.2MPa, or a value or range between any two of the above). In certain embodiments, the inlet of the external homogenizing pump is provided at a value or range between 80mm and 110mm (e.g., 85mm, 90mm, 95mm, 96mm, 97mm, 98mm, 99mm, 100mm, 105mm, 110mm, or any two of the above). In certain embodiments, the outlet of the external homogenizing pump is provided at 60mm to 90mm (e.g., 65mm, 70mm, 75mm, 76mm, 77mm, 78mm, 79mm, 80mm, 81mm, 82mm, 83mm, 84mm, 85mm, 90mm, or any value or range between two of the foregoing values).

The term "supercritical reactor" as used herein refers to a reactor capable of allowing a reactant to be in a supercritical state or a reaction to be carried out in a supercritical medium, and parameters such as pressure, temperature and the like of the reactor can be adjusted according to reaction requirements (such as types and properties of the reactant and the like) so as to ensure the supercritical reaction to be carried out. The supercritical reactor used in the present application may be any commercially available supercritical reactor, such as an L-series high temperature high pressure supercritical reactor available from Shanghai Lai North scientific instruments Co.

The reactant amine stream described in step (a) may enter the supercritical reactor through a single reactant amine-containing substream, or through multiple (e.g., 2, 3, 4, 5, or more) reactant amine-containing substreams. Likewise, the phosgene stream described in step (a) may enter the supercritical reactor through a single phosgene-containing substream or through multiple (e.g., 2, 3, 4, 5 or more) phosgene-containing substreams. When the reactant amine stream (or phosgene stream) in step (a) enters the supercritical reactor through multiple substreams containing the reactant amine (or phosgene), multiple substreams may enter the supercritical reactor at the same location or may enter the supercritical reactor at different locations.

In the preparation of isocyanates, it is often necessary to add a large excess of phosgene, since, in the case of insufficient phosgene concentrations, the isocyanate formed forms instead with the excess amine urea or other high-viscosity solid by-products. Therefore, in order to prevent the formation of by-products, phosgene is preferably supplied in an excess form. For example, in certain embodiments, the phosgene stream described in step (a) is in stoichiometric excess based on the amino groups of the reactant amine stream. For example, the molar ratio of phosgene to amine groups of the reactant amine is typically 1.1:1 to 50:1 (e.g., 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 11:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, and ranges between any of the foregoing). In certain embodiments, phosgene is used in stoichiometric excess of 0% to 250% (e.g., 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, etc.) of the theoretical value based on the amino groups of the reactant amine in the supercritical reactor. When the reactant amine stream (and/or phosgene stream) described in step (a) enters the supercritical reactor through a plurality of reactant amine (and/or phosgene) -containing substreams, the plurality of phosgene-containing substreams and the total phosgene stream produced are stoichiometrically excess based on the amino groups of the plurality of reactant amine-containing substreams and the total reactant amine stream produced.

In certain embodiments, the ratio of the phosgene stream to the reactant amine stream (on a molar basis) described in step (a) is from 7:1 to 25:1 (e.g., 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, or any value between any two of the above). Preferably, the ratio of the phosgene stream to the reactant amine stream feed (on a molar basis) as described in step (a) is from 10:1 to 20:1.

The phosgene contained in the phosgene stream described in step (a) may be fresh phosgene or recycled phosgene. The term "fresh phosgene" refers to a phosgene-containing stream which has not been recycled from the phosgenation process and which has not been subjected to any reaction stage involving the reaction of phosgene after synthesis of phosgene, typically from chlorine and carbon monoxide. The term "recycled phosgene" refers to the phosgene-containing stream produced in the tail gas collected from the reaction process for the preparation of isocyanates by the phosgenation process. As described above, in the process of preparing isocyanate by gas phase method, it is often necessary to use excessive phosgene, so that a large amount of phosgene is contained in the reaction tail gas, and the purpose of reducing production cost can be achieved by recycling the phosgene in the tail gas. In certain embodiments, the phosgene stream described in step (a) is present in liquid form.

In certain embodiments, the reactant amine stream and phosgene stream described in step (a) are mixed at low temperature, e.g., at any temperature between-5 and 5 ℃, such as-5 ℃, -4 ℃, -3 ℃, -2 ℃, -1 ℃, 0 ℃, 1 ℃, 2 ℃, 3 ℃, 4 ℃, 5 ℃, or any value between any two of the above values. The mixing may be carried out at any constant temperature between-5 and 5 ℃, or at a varying temperature between-5 and 5 ℃. In one embodiment, the mixing is performed at a constant temperature of 0 ℃.

In certain embodiments, step (a) is performed before step (b) and step (c), i.e., the reactants amine and phosgene are mixed prior to their reaction and then reacted together at elevated temperature. One of the advantages of such an operation is that decomposition of the reactant amine (e.g., amine salt) at high temperatures, or self-cyclization to produce byproducts, can be avoided.

2.Step (b)

In step (b) of the present application, the temperature of the mixture obtained in step (a) is adjusted to 182 to 205 ℃ so that the phosgene is in a supercritical state, and the reaction is performed in a supercritical reactor for at least 15 minutes.

Taking as an example the starting reaction materials of glutaric amine hydrochloride and phosgene, the reaction mainly carried out in step (b) is as follows:

In certain embodiments, in step (b), the temperature of the supercritical reactor is adjusted to 182-205 ℃ such that the phosgene is in a supercritical state and the reactant amine and the phosgene react for no less than 15 minutes.

The "supercritical state" in the present application means a state in which the fluid is interposed between a gas and a liquid by increasing the temperature and the pressure of the fluid so that the temperature is not lower than the critical temperature and the pressure is not lower than the critical pressure. Many physical and chemical properties of a substance in a supercritical state are between those of a gas and a liquid, and have advantages of both, such as strong solubility, good diffusion performance, easy control, and the like, and have both a solubility capacity and a heat transfer coefficient similar to those of a liquid and a viscosity coefficient and a diffusion coefficient similar to those of a gas. For example, phosgene has a critical temperature of 182℃and a critical pressure of 5.674MPa. When the temperature of phosgene is 182℃or more and the pressure is 5.674MPa or more, phosgene is in a supercritical state.

In general, amine salts are practically insoluble in any common organic solvent and can only be dispersed in the solvent. The inventors of the present application have unexpectedly found that phosgene in a supercritical state can dissolve a reactant amine (particularly an amine salt) to allow the phosgene in a supercritical state to react with the reactant amine, and that the phosgene in a supercritical state serves as a solvent for the reactant amine and also serves as a starting material for the reaction, so that it is not only unnecessary to dissolve the reactant amine by using other solvents alone, but also the reaction rate can be greatly increased. In addition, when the reactant amine is an amine salt (e.g., PDA hydrochloride), cyclization reaction deterioration during the temperature elevation of the amine salt alone can also be effectively avoided. In certain embodiments, no organic solvent is used in step (b) of the present application.

In certain embodiments, step (b) is performed at a pressure of 5MPa (e.g., 5.1MPa, 5.2MPa, 5.3MPa, 5.4MPa, 5.5MPa, 5.6MPa, 5.7MPa, 5.8MPa, 5.9MPa, 6MPa, 6.1MPa, 6.2MPa, 6.3MPa, 6.4MPa, 6.5MPa, 6.6MPa, 6.7MPa, 6.8MPa, 6.9MPa, 7MPa, 7.5MPa, 8MPa, 8.1MPa, 8.2MPa, 8.3MPa, 8.4MPa, 8.5MPa, 8.6MPa, 8.7MPa, 8.8MPa, 8.9MPa, 9MPa, 9.1MPa, 9.2MPa, 9.3MPa, 9.4MPa, 9.5MPa, 9.7MPa, 9.8MPa, 9.9MPa, 10MPa, 11MPa, 12MPa or more), at a temperature of 182℃or more, for example, between 182 ℃,182 ℃, 183 ℃, 184 ℃, 185 ℃, 186 ℃, 187 ℃, 188 ℃, 189 ℃, 190 ℃, 191 ℃, 192 ℃, 193 ℃, 194 ℃, 195 ℃, 196 ℃, 197 ℃, 198 ℃, 199 ℃, 200 ℃, 201 ℃, 202 ℃, 203 ℃, 204 ℃, 205 ℃, or any value between any two values of the above). In certain embodiments, the reaction pressure of step (b) is 5.2MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 6.2MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 6.3MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 6.4MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 6.5MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 6.6MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 6.7MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 6.9MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 7MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 7.8MPa and the reaction temperature is 182 ℃. In certain embodiments, the reaction pressure of step (b) is 8.4MPa and the reaction temperature is 182 ℃.

In certain embodiments, to ensure adequate reaction of the reactant amine and phosgene, in step (b), the reaction time for both should be no less than 15 minutes, such as 16 minutes, 17 minutes, 18 minutes, 19 minutes, 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, or any value between any two of the above. In certain embodiments, in step (b), the reaction time of the reactant amine and phosgene is 20 minutes. In certain embodiments, in step (b), the reaction time of both should be no less than 30 minutes, for example 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes, 35 minutes, 36 minutes, 37 minutes, 38 minutes, 39 minutes, 40 minutes, or any value in between any two of the above.

3.Step (c)

In step (c) of the present application, the reaction product mixture obtained in step (b) is reacted under reduced pressure for a reaction time of not more than 30 seconds.

Taking as an example the starting reaction materials of glutaric amine hydrochloride and phosgene, the reaction mainly carried out in step (c) is as follows:

the reaction product mixture produced after step (b) includes an acid chloride intermediate, unreacted complete reactant amine and phosgene. Step (c) is a step of decomposing the acid chloride intermediate to form isocyanate. The applicant has unexpectedly found that the preparation time of isocyanate can be significantly shortened by performing the acid chloride decomposition reaction under reduced pressure, and the problem of excessive supercritical reaction pressure can be solved. In conventional processes for preparing isocyanates using phosgene, the residence time of the phosgenation reaction takes several hours or even more than ten hours and the pressure can reach 9 to 10MPa. In the process of the present application, the isocyanate production time can be reduced to less than 30 minutes and the pressure can be reduced to 6 to 8MPa by combining the supercritical phosgenation reaction (i.e., step (b)) with the reduced pressure reaction (i.e., step (c)).

In certain embodiments, the reaction pressure of step (c) is from 15KPa to 500KPa, e.g., 15KPa, 50KPa, 60KPa, 70KPa, 80KPa, 90KPa, 100KPa, 110KPa, 120KPa, 130KPa, 140KPa, 150KPa, 200KPa, 210KPa, 220KPa, 230KPa, 240KPa, 250KPa, 260KPa, 270KPa, 280KPa, 290KPa, 300KPa, 310KPa, 320KPa, 330KPa, 340KPa, 350KPa, 400KPa, 450KPa, 500KPa or any value between any two of the above value ranges. In certain embodiments, the reaction pressure of step (c) is from 50KPa to 300KPa. In certain embodiments, the reaction pressure of step (c) is from 50KPa to 140KPa. In certain embodiments, the reaction pressure of step (c) is from 50KPa to 110KPa. In certain embodiments, the reaction pressure of step (c) is from 70KPa to 150KPa.

There are various ways in which step (c) can be carried out under reduced pressure. In certain embodiments, step (c) is to introduce the reaction product mixture in the supercritical reactor of step (b) into a reduced pressure reactor for reaction. For example, after step (b) is completed, a valve between the supercritical reactor and the reduced pressure reactor is opened to introduce the reaction product mixture of step (b) into the reduced pressure reactor for reaction. In certain embodiments, the reduced pressure reactor is a pipeline reactor (e.g., a pipeline reduced pressure reactor). The pipeline reactor is a continuous operation reactor which is tubular and has larger length-diameter ratio. The length of the pipeline reactor is flexible, and the pipeline reactor is characterized in that the pipeline reactor can realize serialization and the reaction can not be backmixed. In certain embodiments, the reduced pressure reactor has a conduit inner diameter of 4 to 9mm (e.g., 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, or any value therebetween).

In certain embodiments, the reduced pressure reactor is preheated to a temperature required for the reaction of the step (i.e., the acid chloride decomposition reaction) prior to introducing the reaction product mixture into the reduced pressure reactor. In certain embodiments, the reaction temperature of step (c) is 150 ℃ to 450 ℃, e.g., 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃, 410 ℃, 420 ℃, 430 ℃, 440 ℃, 450 ℃, or any value between any two of the above. Preferably, the reaction temperature of step (c) is from 200 ℃ to 400 ℃. More preferably, the reaction temperature of step (c) is from 250 ℃ to 350 ℃. In certain embodiments, the reaction temperature of step (c) is 300 ℃.

In certain embodiments, the reaction residence time of step (c) is from 0.5 seconds to 30 seconds, e.g., 30 seconds, 25 seconds, 20 seconds, 15 seconds, 10 seconds, 9 seconds, 8 seconds, 7 seconds, 6 seconds, 5 seconds, 4.5 seconds, 4 seconds, 3.5 seconds, 3 seconds, 2.5 seconds, 2 seconds, 1.5 seconds, 1 second, 0.5 seconds, or any value between any two of the above. Preferably, the reaction residence time of step (c) is from 1.5 seconds to 20 seconds. More preferably, the reaction residence time of (c) is from 2.5 seconds to 10 seconds. The reaction residence time of step (c) may be controlled by a variety of methods, for example by controlling the flow rate of the reaction product mixture of step (b) and/or the inside diameter of the piping reactor.

In certain embodiments, no organic solvent is used in step (c).

4.Step (d)

In certain embodiments, the methods of making of the present application further comprise step (d) collecting the product.

In certain embodiments, step (d) of the present application comprises: providing a quench zone at the outlet of the depressurization reactor such that the reaction product mixture obtained in step (c) is contacted with a quench medium stream passing into the quench zone to reduce the temperature of the reaction product mixture obtained in step (c) to below 170 ℃.

In certain embodiments, the product collection temperature of step (d) is 170 ℃ or less, e.g., 170 ℃, 165 ℃, 160 ℃, 155 ℃, 150 ℃, 145 ℃, 140 ℃, 135 ℃, 130 ℃, 125 ℃, 120 ℃, 115 ℃, 110 ℃, 105 ℃, 100 ℃, 95 ℃, 90 ℃, 85 ℃, 80 ℃, 75 ℃, 70 ℃, or any value in any range between any two of the above. In certain embodiments, the product collection temperature of step (d) is from 80 ℃ to 150 ℃. In certain embodiments, the product collection temperature of step (d) is from 110 ℃ to 140 ℃.

In certain embodiments, in step (d), the latent heat of vaporization of the quenching medium is utilized to rapidly reduce the temperature of the reaction product mixture obtained in step (c). Organic solvents (e.g., toluene, chlorobenzene, chloronaphthalene), isocyanates or mixtures of solvents and isocyanates are commonly used in the art as quench media to reduce the temperature of the supercritical reactor. In certain embodiments, the quenching medium described in step (d) is selected from the group consisting of: an organic solvent, isocyanate, phosgene, hydrogen chloride, an inert carrier gas, and any combination thereof. In certain embodiments, the organic solvent is selected from the group consisting of: dichloromethane, chlorobenzene, o-dichlorobenzene, benzene, toluene, xylene, hexane, tetrahydrofuran, chloronaphthalene, and any combination thereof. In certain embodiments, the quenching medium is a liquid (e.g., liquid phosgene). In certain embodiments, the reaction product mixture obtained in step (c) is rapidly reduced in temperature by using phosgene or a mixture of phosgene and isocyanate as a quench medium. Without being bound by any theory, it is believed that the use of phosgene or a mixture of phosgene and isocyanate as the quenching medium works better than the use of an organic solvent as the quenching medium. For example, the use of phosgene or the mixture of phosgene and isocyanate as a quenching medium can avoid the use of an organic solvent in the whole reaction system and the problem of inlet blockage caused by solid coanda, so that the whole process has no links of solvent recovery, rectification and cyclic refining, and the preparation process is simpler, lower in energy consumption and lower in cost. Meanwhile, the high-temperature refining process is shortened, so that the high-temperature residence time of the isocyanate as a reaction product is greatly shortened, the self-polymerization reaction is reduced, and the product yield is higher.

5.Step (e)

In certain embodiments, the methods of making of the present application further comprise step (e) purifying the product.

In certain embodiments, step (e) comprises the sub-steps of:

Taking fig. 1 as an example, in substep 1), the reaction product mixture obtained in step (c) or step (d) is passed into a degassing column 04, wherein hydrogen chloride and phosgene in the reaction product mixture overflow from the top of the degassing column 04 and enter a hydrogen chloride/phosgene separation column 05, wherein the hydrogen chloride overflowed from the top of the separation column 05 is refined by a tail gas removal treatment unit to form hydrochloric acid as a by-product.

Taking fig. 1 as an example, in substep 2) phosgene is recovered from the bottom of the hydrogen chloride/phosgene separation column 05 to form a phosgene stream which is recycled into the supercritical reactor 01.

Taking fig. 1 as an example, in substep 3), the isocyanate and by-products of the reaction product mixture are collected from the bottom of the deaerator 04 and passed through a light component removal column 06 to remove the light component by-products. Wherein said light component byproducts may be conventional in the art; in certain embodiments, the light component byproducts are selected from the group consisting of: piperidine, polyhydropyridine, or combinations thereof. Taking fig. 1 as an example, in sub-step 4), isocyanate and heavy component byproducts are collected from the bottom of the light component removal column 06, passed through a refining column 07, isocyanate is collected from the refining column, and heavy component byproducts are removed. Wherein the heavy component by-product may be conventional in the art, and in certain embodiments is selected from the group consisting of: tar, PDI self-polymerization, by-product urea, or any combination thereof. When the reactant amine is an amine salt, the process for preparing the isocyanate of the present application avoids the step of converting the amine salt to an amine compared to conventional gas or liquid phase phosgenation; compared with the existing salt-forming phosgene process, the supercritical state phosgene used in the application can be used as a solvent of reactant amine and also can be used as a starting material of the reaction, so that a large amount of solvent is avoided. In addition, in the process of preparing isocyanate by using the method, the supercritical phosgenation reaction and the decompression reaction are combined to generate synergistic effect, for example, the problems of insufficient speed and excessive pressure of the pure supercritical reaction are avoided; but also avoids the problems of higher impurity content, incomplete reaction and the like of simple pipeline reaction. In addition, the mixture of phosgene or phosgene and isocyanate is used as a quenching medium in the reaction process, so that the problem of inlet blockage caused by the attachment of solid walls can be avoided, the links of solvent recovery, rectification and circulating refining are omitted in the whole process, the preparation process is simpler and more convenient, the energy consumption is lower, and the cost is lower.

The foregoing is a summary of the application and there may be a simplification, generalization, and omission of details, so it will be recognized by those skilled in the art that this section is merely illustrative and is not intended to limit the scope of the application in any way. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Examples

In order that the application may be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting in any way.

Some of the noun abbreviations mentioned in the examples are shown in table 1.

Table 1: noun abbreviations

English abbreviations	Chinese name
		PDI	Pentamethylene diisocyanate
PDA	Pentanediamine

The material ratios, reaction conditions, final yields, and the like used in the respective examples below are summarized in table 2.

Table 2: preparation of PDI from PDA hydrochloride (example 1A-1T quench medium was phosgene, example 1U quench medium was phosgene+PDI mixture)

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Example 1A: PDI preparation by PDA hydrochloride

175g (1 mol) PDA hydrochloride and 1188g (12 mol) liquid phosgene are stirred and mixed uniformly at 0 ℃, and are fed into a 10L autoclave (supercritical reactor) which is internally provided with a homogenizing device.

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.6 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pressure of a pipeline to be 80KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then 159.4g of the residue was weighed for gas phase quantitative analysis, which showed 88.6% content and 92.3% yield.

Example 1B: PDI preparation from PDA hydrochloride (without mixing PDA hydrochloride and phosgene, separately preheated)

PDA hydrochloride and liquid phosgene were heated to 182 ℃ in two high pressure lines, respectively.

Preheating a 4mm inner diameter tubular reactor (decompression reactor) to reach the temperature of 300 ℃, introducing phosgene and PDA hydrochloride heated to 182 ℃ into the tubular reactor according to the molar ratio of 12:1, controlling the passing time to be 5s, simultaneously controlling the pipeline pressure to be 80KPa, and enabling the effluent gas (liquid) to pass through the-20 ℃ phosgene extremely cold capturing and drawing to obtain a product collecting liquid.

The collected liquid is separated to obtain hydrogen chloride gas, and phosgene is recovered, and then the residue is analyzed in a gas phase, so that a large amount of impurities are found, and the impurities are separated and then are analyzed into the dihydropyridine impurities.

Example 1C: PDI preparation of PDA hydrochloride (heterogeneous shearing)

175g (1 mol) of PDA hydrochloride and 1188g (12 mol) of liquid phosgene are stirred and mixed uniformly at 0℃and fed into a 10L autoclave (supercritical reactor) which is free of built-in homogenizing device.

And (3) starting stirring, heating the reaction liquid without shearing and homogenizing, then heating the 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is greater than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.9 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pressure of a pipeline to be 80KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid, and finding that a pipeline is blocked after the outflow gas (liquid) is fed to about half of the reaction liquid, so that the reaction cannot be continued.

The collected liquid was separated to recover phosgene, and then the residue was weighed to obtain 76.1g for gas phase quantitative analysis, which showed a content of 87.9% and a yield of 43.7%.

Example 1D: PDI preparation of PDA hydrochloride (inner diameter of 3mm reaction tube)

And (3) starting stirring, heating the reaction liquid without shearing and homogenizing, then heating the 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 7.0 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 3mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pressure of a pipeline to be 80KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid, and finding that a pipeline is blocked after the outflow gas (liquid) is fed to about half of the reaction liquid, so that the reaction cannot be continued.

The collected liquid was separated to recover phosgene, and then the residue was weighed to give 44.6g for gas phase quantitative analysis, which showed 88.2% content and 25.7% yield.

Example 1E: PDI preparation of PDA hydrochloride (inner diameter of reaction tube 5 mm)

And (3) starting stirring, heating the reaction liquid without shearing and homogenizing, then heating the 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is greater than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.5 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 5mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to ensure that the time of the reaction liquid passing through the tubular reactor is 5s (namely, the residence time is 5 s), controlling the pressure of a pipeline to be 80KPa, and simultaneously, ensuring that the outflow gas (liquid) passes through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then 165.0g of the residue was weighed for gas phase quantitative analysis, which showed a content of 82.9% and a yield of 89.4%.

Example 1F: PDI preparation of PDA hydrochloride (inner diameter of 8mm reaction tube)

And (3) starting stirring, heating the reaction liquid without shearing and homogenizing, then heating the 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is greater than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.6 MPa.

Preheating an 8mm inner diameter tubular reactor (decompression reactor) to reach the temperature of 300 ℃, then slowly opening an autoclave valve, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pipeline pressure to be 80KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then 157.1g of the residue was weighed for gas phase quantitative analysis, which showed a content of 79.3% and a yield of 81.4%.

Example 1G: PDI preparation of PDA hydrochloride (inner diameter of 10mm reaction tube)

Preheating a 10mm inner diameter tubular reactor (decompression reactor) to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pipeline pressure to be 80KPa, enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid, and detecting that the collecting liquid has more yellowish white solid as a raw material.

The collected liquid was separated to recover phosgene, and then 142.4g of the residue was weighed and quantitatively analyzed in a gas phase, which showed a content of 43.4% and a yield of 40.4%.

Example IH: PDI preparation of PDA hydrochloride (350 ℃ C. Reaction)

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 7.0 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to a temperature of 350 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pressure of a pipeline to be 80KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then the residue was weighed to obtain 151.3g for gas phase quantitative analysis, which showed a content of 82.2% and a yield of 81.3%.

Example 1I: PDI preparation of PDA hydrochloride (400 ℃ C. Reaction)

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.7 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 400 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to ensure that the time of the reaction liquid passing through the tubular reactor is 5s (namely, the residence time is 5 s), controlling the pressure of a pipeline to be 80KPa, and simultaneously, ensuring that the outflow gas (liquid) passes through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid which contains more tar and carbon residues.

The collected liquid was separated to recover phosgene, and then 129.2g of the residue was weighed for gas phase quantitative analysis, which showed a content of 63.0% and a yield of 53.2%.

Example 1J: PDI preparation of PDA hydrochloride (250 ℃ C. Reaction)

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.4 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to a temperature of 250 ℃, then slowly opening an autoclave valve, controlling the outflow speed of the reaction liquid through a regulating valve, enabling the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), simultaneously controlling the pipeline pressure to be 80KPa, enabling the effluent gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid, wherein the collecting liquid is white solid, and analyzing the product collecting liquid to be the raw material PDA hydrochloride.

The collected liquid was separated to recover phosgene, and the residue was weighed to 173.3g for gas phase quantitative analysis, which showed a content of 70.0% and a yield of 79.3%.

Example 1K: PDA hydrochloride preparationPDI (PDA hydrochloride: phosgene=1:10 molar ratio)

175g (1 mol) of PDA hydrochloride and 990g (10 mol) of phosgene were stirred and mixed uniformly at 0℃and fed into a 10L autoclave (supercritical reactor) which was internally provided with a homogenizing device.

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 5.7 MPa.

The collected liquid was separated to recover phosgene, and then 153.8g of the residue was weighed for gas phase quantitative analysis, which showed a content of 87.7% and a yield of 88.2%.

Example 1L: PDI preparation from PDA hydrochloride (PDA hydrochloride: phosgene=1:16 molar ratio)

175g (1 mol) of PDA hydrochloride and 1584g (16 mol) of phosgene are stirred and mixed uniformly at 0 ℃ and are fed into a 10L autoclave (supercritical reactor) which is internally provided with a homogenizing device.

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 7.8 MPa.

The collected liquid was separated to recover phosgene, and then 156.9g of the residue was weighed for gas phase quantitative analysis, which showed 88.9% content and 91.2% yield.

Example 1M: PDI preparation from PDA hydrochloride (PDA hydrochloride: phosgene=1:20 molar ratio)

175g (1 mol) of PDA hydrochloride and 1977.5g (20 mol) of phosgene are stirred and mixed uniformly at 0 ℃ and are fed into a 10L autoclave (supercritical reactor) which is internally provided with a homogenizing device.

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 8.4 MPa.

The collected liquid was separated to recover phosgene, and then 158.7g of the residue was weighed for gas phase quantitative analysis, which showed 89.2% content and 92.5% yield.

Example 1N: PDI (residence time 1 s) preparation of PDA hydrochloride

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.3 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 1s (namely, the residence time to be 1 s), simultaneously controlling the pressure of a pipeline to be 80KPa, and enabling the effluent gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid, wherein the collecting liquid is white solid, and analyzing the product collecting liquid to be the raw material PDA hydrochloride.

The collected liquid was separated to recover phosgene, and then 167.5g of the residue was weighed for gas phase quantitative analysis, which showed a content of 55.0% and a yield of 60.2%.

Example 1O: PDI preparation of PDA hydrochloride (residence time 2.5 s)

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.2 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 2.5s (namely, the residence time to be 2.5 s), controlling the pipeline pressure to be 80KPa, and enabling the outflow gas (liquid) to pass through phosgene with the temperature of-20 ℃ to be extremely cold and caught to obtain a product collecting liquid, wherein the collecting liquid is white solid, and analyzing the white solid into the raw material PDA hydrochloride.

The collected liquid was separated to recover phosgene, and then 156.1g of the residue was weighed for gas phase quantitative analysis, which showed a content of 69.8% and a yield of 71.2%.

Example 1P: PDI preparation of PDA hydrochloride (residence time 10 s)

Starting stirring and simultaneously starting a built-in homogenizing pump, shearing and uniformly mixing, heating a 10L autoclave, slowly raising the temperature in the autoclave to 182 ℃ (phosgene supercritical temperature), observing the pressure, continuing the subsequent operation if the pressure is less than 10MPa, stopping heating if the pressure is more than 10MPa, and keeping the temperature for 20min under the condition that the temperature reaches 182 ℃ and the recording pressure is 6.5 MPa.

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to ensure that the time of the reaction liquid passing through the tubular reactor is 10s (namely, the residence time is 10 s), controlling the pressure of a pipeline to be 80KPa, and simultaneously, ensuring that the outflow gas (liquid) passes through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then 155.3g of the residue was weighed for gas phase quantitative analysis, which showed 88.0% content and 89.3% yield.

Example 1Q: PDI preparation of PDA hydrochloride (residence time 20 s)

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve, enabling the time of the reaction liquid passing through the tubular reactor to be 20s (namely, the residence time to be 20 s), controlling the pipeline pressure to be 80KPa, and enabling the effluent gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid which contains more tar and carbon residues.

The collected liquid was separated to recover phosgene, and then the residue was weighed to give 176.7g for gas phase quantitative analysis, which showed 54.2% content and 62.6% yield.

Example 1R: PDI (pipeline pressure 50 KPa) prepared from PDA hydrochloride

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pipeline pressure to be 50KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then 160.9g of the residue was weighed for gas phase quantitative analysis, which showed a content of 81.9% and a yield of 85.6%.

Example 1S: PDI (pipeline pressure 110 KPa) prepared from PDA hydrochloride

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pipeline pressure to be 110KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then the residue was weighed to obtain 152.3g for gas phase quantitative analysis, which showed a content of 74.3% and a yield of 73.5%.

Example 1T: PDI (pipeline pressure 140 KPa) prepared from PDA hydrochloride

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve to enable the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pressure of a pipeline to be 140KPa, and enabling the outflow gas (liquid) to pass through phosgene extremely cold capturing at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then 162.3g of the residue was weighed for gas phase quantitative analysis, which showed a content of 68.6% and a yield of 72.3%.

Example 1U: PDI preparation of PDA hydrochloride (phosgene+PDI quench Drain)

Preheating a tubular reactor (decompression reactor) with an inner diameter of 4mm to reach the temperature of 300 ℃, then slowly opening a valve of an autoclave, controlling the outflow speed of the reaction liquid through a regulating valve, enabling the time of the reaction liquid passing through the tubular reactor to be 5s (namely, the residence time to be 5 s), controlling the pipeline pressure to be 80KPa, and enabling the outflow gas (liquid) to pass through the extremely cold capturing of phosgene and PDI (total amount of phosgene 6000g+PDI 220 g) at the temperature of-20 ℃ to obtain a product collecting liquid.

The collected liquid was separated to recover phosgene, and then the residue was weighed to obtain 380.6g for gas phase quantitative analysis, which showed 88.4% content, deducting 220g of PDI for quenching and capturing, and the reaction yield was 92.1%.

Claims

1. A process for preparing an isocyanate, said process comprising the steps of:

(a) Mixing a reactant amine stream and a phosgene stream at a temperature of-5 to 5 ℃ to obtain a mixture of reactant amine and phosgene, wherein the reactant amine stream and the phosgene stream are sheared and emulsified uniformly by a homogenizing pump;

(b) Regulating the temperature of the mixture obtained in the step (a) to 182-205 ℃ so that the phosgene is in a supercritical state, and carrying out reaction in a supercritical reactor for 15-40 minutes;

(c) Reacting the reaction product mixture obtained in the step (b) in a pipeline reactor under the condition of reduced pressure for 2.5 to 20 seconds, wherein the pipeline inside diameter of the pipeline reactor is 4 to 10mm, the reaction pressure is 50KPa to 140KPa, and the reaction temperature is 250 ℃ to 400 ℃;

wherein the structural formula of the reactant amine is R (NH) ₂ ) _n Wherein n is 2 and R is an aliphatic hydrocarbylene group having 2-10 carbon atoms or an aromatic hydrocarbylene group having 3-10 carbon atoms.

2. The method of claim 1, further comprising the step of (d) collecting the product.

3. The method of claim 2, wherein step (d) comprises: providing a quench zone at the outlet of said depressurization reactor such that the reaction product mixture obtained in step (c) is contacted with a stream of quench medium passing into said quench zone to reduce the temperature of said reaction product mixture obtained in step (c) to below 170 ℃, wherein said quench medium is selected from the group consisting of: an organic solvent, isocyanate, phosgene, hydrogen chloride, an inert carrier gas, and any combination thereof.

4. The method of claim 2, further comprising the step of (e) purifying the product.

5. The method of claim 4, wherein step (e) comprises:

6. The method of claim 1, wherein step (a) is performed before step (b) and step (c).

7. The method of claim 1, wherein no organic solvent is used in step (a), step (b) and step (c).

8. The method of claim 1, wherein in step (a), the mixing is performed by introducing the reactant amine stream and the phosgene stream into a supercritical reactor.

9. The method of claim 1, wherein in step (a), the reactant amine stream and the phosgene stream are mixed and then shear emulsified to form suspended particles.

10. The method of claim 9, wherein the shear emulsification is performed in the supercritical reactor.

11. The method of claim 9, wherein the suspended particles have a diameter of less than or equal to 100 μm.

12. The method of claim 11, wherein the suspended particles have a diameter of less than or equal to 50 μιη.

13. The method of claim 11, wherein the suspended particles have a diameter of less than or equal to 20 μιη.

14. The method according to claim 1, wherein the shear emulsification uniformity is achieved by controlling the lift, rotational speed, torque, suction force and/or shear homogenization time of the homogenizing pump.

15. The method of claim 14, wherein the circulating output volume of the homogenizing pump is controlled to be greater than or equal to 10 times the volume of the liquid holdup in the supercritical reactor.

16. The method of claim 1, wherein the phosgene stream in step (a) is in stoichiometric excess based on the amino groups of the reactant amine stream.

17. The process of claim 1, wherein the molar amount of phosgene stream and reactant amine stream feed in step (a) is in the range of 7:1 to 25:1.

18. The method of claim 17, wherein the molar ratio of the phosgene stream to reactant amine stream feed in step (a) is 12:1.

19. The method of claim 1, wherein the phosgene stream in step (a) is present in liquid form.

20. The process of claim 1, wherein the reaction temperature of step (c) is from 250 ℃ to 350 ℃.

21. The process of claim 1, wherein the reaction pressure in step (c) is from 50KPa to 110KPa.

22. The process of claim 1 wherein the reaction residence time of step (c) is from 2.5 seconds to 10 seconds.

23. The process of claim 2 wherein the product collection temperature of step (d) is 170 ℃ or less.

24. The process of claim 2, wherein the product collection temperature of step (d) is from 80 ℃ to 150 ℃.

25. The process of claim 2, wherein the product collection temperature of step (d) is from 110 ℃ to 140 ℃.

26. A process according to claim 3, wherein in step (d) the reaction product mixture temperature obtained in step (c) is rapidly reduced using the latent heat of vaporization of the quenching medium.

27. A method according to claim 3, wherein the organic solvent is selected from the group consisting of: dichloromethane, chlorobenzene, o-dichlorobenzene, benzene, toluene, xylene, hexane, tetrahydrofuran, chloronaphthalene, and any combination thereof.

28. A process according to claim 3, wherein the quenching medium in step (d) is in a liquid state.

29. The method of claim 28, wherein the quenching medium in step (d) is liquid phosgene.

30. The method according to claim 1, wherein the pipeline reactor has a pipeline inner diameter of 4 to 9mm.

31. The method of claim 1, wherein the isocyanate is a diisocyanate.

32. The method according to claim 1, wherein the isocyanate is an aliphatic diisocyanate or an aromatic diisocyanate.

33. The process according to claim 1, wherein the isocyanate is toluene diisocyanate or 1, 5-naphthalene diisocyanate as pure isomer or as a mixture of isomers.

34. The method according to claim 1, wherein the isocyanate is pentanediisocyanate, hexanediisocyanate, or terephthalisocyanate.

35. The method of claim 1, wherein the isocyanate is PDI, HDI, IPDI or HTDI.

36. The method of claim 1, wherein the reactant amine has the formula R (NH ₂ ) _n Wherein n is 2 and R is a linear or cyclic aliphatic alkylene group having 3 to 10 carbon atoms.

37. The method of any one of claims 1-36, wherein the reactant amine is present in free form.

38. The method of any one of claims 1-36, wherein the reactant amine is present in the form of an amine salt.

39. The method of claim 38, wherein the amine salt is selected from the group consisting of: hydrochloride, sulfate, bisulfate, nitrate and carbonate.

40. The method of any one of claims 1-32, wherein the reactant amine is selected from one or more of the group consisting of: pentanediamine, hexamethylenediamine, 1, 4-diaminobutane, 1, 8-diaminooctane, p-phenylenediamine, m-xylylenediamine, toluenediamine, 1, 5-naphthalenediamine, m-cyclohexyldimethylenediamine, isophoronediamine, methylcyclohexamethylenediamine, trans-1, 4-cyclohexanediamine.

41. The method of any one of claims 1-32, wherein the reactant amine is selected from the group consisting of: PDA, PDA hydrochloride, HDA hydrochloride, IPDA hydrochloride, HTDA and HTDA hydrochloride.