CN116041187A - Method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction and application thereof - Google Patents
Method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction and application thereof Download PDFInfo
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Abstract
The invention relates to a method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction and application thereof. The method comprises the steps of filling a large-aperture zeolite molecular sieve serving as a catalyst into a fixed bed, taking ammonia which is a product obtained by carbonate and the like as a gas-phase ammonia source, adopting a continuous feeding process with methanol gas phase matters, catalyzing and synthesizing to obtain a methylamine mixture taking trimethylamine as a main product, and further reacting with carbon dioxide in the carbonate and the like to obtain methylamine (hydrogen) carbonate. The product methylamine (hydrogen) carbonate can further carry out base catalysis ring-opening reaction with epoxy compound to prepare mixed methylamine quaternary ammonium (hydrogen) carbonate salt with better stability at normal temperature, and the methylamine ammonium (hydrogen) carbonate salt and the methylamine quaternary ammonium (hydrogen) carbonate salt are used for preparing polyurethane rigid foam plastic materials with good comprehensive performance. The invention improves the safety and environmental protection of ammonia source, the continuous synthesis process is efficient, and the product is green and environmental-friendly for manufacturing polyurethane hard foam plastics.
Description
Technical Field
The invention belongs to the technical field of fine chemical engineering, and particularly relates to a method for preparing mixed methylamine ammonium carbonate by a continuous fixed bed catalytic reaction in situ and application thereof.
Background
Methylamine, including monomethylamine, dimethylamine and trimethylamine, has wide industrial applications in medicine, pesticides, dyes, rubber vulcanization accelerators, synthetic feed additives and polycondensation catalysts, respectively; bicarbonate and carbonate salts of methylamines are useful as disinfectants and intermediates in the preparation of quaternary ammonium bicarbonate and carbonate salts; quaternary ammonium hydrogen carbonates and quaternary ammonium carbonates of methylamines are useful in antimicrobial, bactericidal, and corrosion-resistant coatings for metal substrates. For this reason, methylamine carbonate and methylamine carbonate quaternary ammonium compounds have been attracting attention for a long time.
The main way of manufacturing methylamine in modern chemical industry is: the catalyst is prepared by reacting methanol and ammonia in a gas phase at high temperature (about 400 ℃) and high pressure (> 2.5 MPa) in the presence of solid acid catalyst alumina, silica/alumina composition, molecular sieve and the like with dehydration and ammoniation effects. Under the reaction conditions, a mixture of monomethylamine, dimethylamine and trimethylamine is produced, and distillation is usually used for separating and purifying the methylamine mixture. However, since a complex azeotropic system is formed between ammonia and monomethylamine, dimethylamine, and trimethylamine, a very complicated large-scale apparatus is required to perform distillation operation in order to separate each methylamine, and the energy consumption cost of the methylamine production process becomes very high. For example, the "complete collection of improved manufacturing engineering drawings" (25 days, 4 months, 53 years, chemical industry Co., ltd.) is disclosed in detail.
In addition to dimethylamine, monomethylamine and trimethylamine have not been required much, and after dimethylamine has been separated from the reaction product, trimethylamine and monomethylamine have been recycled to the reaction system for reuse. Methods have been disclosed for suppressing trimethylamine formation by utilizing the shape selectivity of zeolite catalysts for amorphous solid acid catalysts governed by thermodynamic equilibrium relationships to promote dimethylamine formation. For example, patent documents (Japanese patent laid-open No. 56-46846) in which mordenite is used as a catalyst; japanese patent application laid-open No. 57-169445 describes a method for producing dimethylamine by disproportionation of trimethylamine; japanese patent application laid-open No. 11-228507 describes a method for producing dimethylamine by disproportionation of monomethylamine.
With the development of the modern chemical industry, the consumption of trimethylamine increases year by year, and corresponding work is being performed on how to improve the trimethylamine yield in the above mixed amine, for example: the chinese patent "method for producing trimethylamine" (CN 101062896 a) provides a method for producing more trimethylamine well while reducing the energy consumption cost in the process of producing methylamine by using zeolite catalyst. Chinese patent "a trimethylamine production device for synthesizing cationic etherifying agent" (CN 216472991U) discloses that rare earth solid acid catalyst is adopted, so that the trimethylamine selectivity is 92%. In the preparation of methylamine by catalysis of methanol and ammonia, U.S. Pat. No. 5,148 (US 4374273) uses aluminosilicate catalysts, by regulating SiO 2 The proportion of Al and the content of monomethylamine, dimethylamine and trimethylamine in the mixed product can be regulated and controlled. The reaction product mixed methylamine in the aforementioned patents is often accompanied by 2 to 3% dimethyl ether by-product. U.S. Pat. No. 3,182,62 describes a SiO 2 -Al 2 O 3 Composition catalyst, the catalystThe chemical agent contains SiO 2 6 percent, has the characteristics of less carbon formation, high methanol conversion rate, trace byproduct dimethyl ether and long service life. Chinese patent "methylamine catalyst and its preparation method" (ZL 00129501.2) provides a SiO 2 -Al 2 O 3 Wherein SiO is a compound of formula (I) 2 The content is 18 to 22 weight percent, al 2 O 3 When the content is 78-82 wt%, the conversion rate of methanol is near 100%, the selectivity of product methylamine is high, the amount of byproduct dimethyl ether is very small, and coking is not easy under the catalysis condition. Certain zeolite, molecular sieve-based catalysts reported in the foregoing patents exhibit shape selectivity for the reaction of ammonia and methanol to methylamine, and for the molecular sizes of three methylamines, abrams et al (j. Catalyst., 1991, 127:9), the behavior of trimethylamine in zeolite is simulated by isopropyl alcohol comparable to the molecular size of trimethylamine, indicating that large pore mordenite, ZSM-5, and HY molecular sieves, etc., facilitate adsorption of trimethylamine, and that the highest level of trimethylamine can be controllably and obtained in the methylamine mixture produced by the reaction of ammonia and methanol.
The preparation of methylamine bicarbonate, carbonate, and its quaternary ammonium bicarbonate and carbonate is carried out by reacting methylamine compound with carbonic acid gas to obtain methylamine bicarbonate or carbonate, and quaternizing to obtain methylamine quaternary ammonium bicarbonate or carbonate.
However, in various methylamine production methods, liquid ammonia has been used as a raw material. Liquid ammonia is a compressible liquefied toxic gas, is colorless liquid under a certain pressure, has higher pressure, and can become flammable and explosive under the influence of environment. Especially the potential long-distance transportation hazard, limits the use of enterprises away from the location of the liquid ammonia feedstock. Therefore, the technological route for producing methylamine by taking liquid ammonia as a raw material has great potential risks in the aspects of safety, environmental protection and economy.
Disclosure of Invention
The inorganic ammonium salt or organic amine compound which is easy to decompose mainly comprises ammonium carbonate, ammonium bicarbonate, ammonium carbamate, aqueous urea solution and the like, and the theoretical decomposition reaction of the compounds is specifically shown in the following formulas (1) to (4):
(NH 4 ) 2 CO 3 →CO 2 +H 2 O+2NH 3 (1)
NH 4 HCO 3 →CO 2 +H 2 O+NH 3 (2)
NH 2 COONH 4 →CO 2 +2NH 3 (3)
(NH 2 ) 2 CO+H 2 O→CO 2 +2NH 3 (4)
Ammonium carbonate is white or colorless semitransparent solid powder with chemical composition of ammonium bicarbonate and carbamic acid hydroxylammonium, and starts to decompose at 30 ℃ and is extremely intense at 55-66 ℃. The decomposition products are ammonia, carbon dioxide and water. The gas generation amount is 700-980 mL/g, and the gas generation amount is highest in the general chemical foaming agent. Ma Junyan et al (Jilin university journal, 2015,45 (6): 1804-1810) show by TG experimental study: the ammonium carbonate and the ammonium carbamate are decomposed from room temperature, the complete decomposition temperature is about 120 ℃, and the decomposition rate of the ammonium carbamate is higher at the same temperature; the initial decomposition temperature of ammonium bicarbonate is about 80 c, at which temperature ammonium bicarbonate only decomposes 1%, whereas ammonium carbamate decomposes 42% at 80 c and ammonium carbonate decomposes 30%. Compared with the other two ammonium salts, the decomposition rate of ammonium bicarbonate is very slow below 80 ℃, and the ammonium bicarbonate starts to decompose rapidly after the decomposition rate exceeds 100 ℃, and the ammonium bicarbonate is completely decomposed at about 150 ℃. The water solubility of urea is very good, the solubility in water at 20 ℃ is 108.0g/100mL, the urea solution with the mass concentration of 50% is generally adopted in industry to carry out the catalytic hydrolysis process for preparing ammonia, and the catalytic urea aqueous solution is rapidly decomposed into ammonia gas and carbon dioxide gas mixture products comprising water vapor at the proper temperature of 130-160 ℃ and the pressure of about 0.35-0.55 MPa. Thus, ammonia in the decomposition products of the above several compounds can be used as an ammonia source for the preparation of methylamine compounds by reaction with methanol. Under the conditions of high temperature and proper pressure under the action of a solid acid catalyst, ammonia and methanol can carry out methylamine reaction of the following formula (5):
Aiming at the defects of safety and environmental protection in the existing methylamine (including monomethylamine, dimethylamine and trimethylamine) production technology which uses liquid ammonia as an ammonia source, the invention provides a method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction and application thereof. The ammonia in the decomposition products is used as an ammonia source by heating and decomposing ammonium carbonate, ammonium bicarbonate, ammonium carbamate and urea aqueous solution, the ammonia is used as a catalyst by adopting a proper molecular sieve solid acid, and a fixed bed catalytic method is adopted to react with methanol to prepare the methylamine mixture, so that the dangerous defect of the raw material liquid ammonia can be overcome, and the process route has higher economy.
The ammonia is produced by decomposing ammonium carbonate, ammonium bicarbonate, ammonium carbamate and urea aqueous solution, and meanwhile, various raw materials simultaneously generate water and carbon dioxide with different molar ratios according to decomposition products, methanol and ammonia pass through a fixed bed reactor filled with the catalyst at high temperature to react to produce methylamine mixture, the water atmosphere phase at high temperature does not lead to acid site deactivation, and the catalytic activity of the catalyst for catalyzing the reaction of the methanol and the ammonia is not influenced. The mixed gas of the reaction products leaves the high-temperature fixed bed reactor, is released by a back pressure valve, is cooled and is sent into the reactor into which quantitative water is put, and carbon dioxide in the mixed gas products can directly react with mixed methylamine solution for salifying reaction to synthesize mixed methylamine bicarbonate and carbonate.
The methylamine solution shows stronger alkalinity than ammonia water, and is easy to react with carbonic acid gas to generate methylamine carbonate; for example, a 50wt% aqueous solution of a methylamine mixture, which still exhibits a strong alkalinity (pH > 13) when the trimethylamine content of the mixed amine is 50wt%, in which case the carbonic acid gas reacts with the mixed methylamine to form mixed methylamine bicarbonate, and when the carbonic acid gas is partially excessive, a small portion of the mixed methylamine carbonate is formed. The specific reaction of the mixed methylamine bicarbonate is as follows in the general formula (6):
wherein R is methyl and n=1, 2 or 3.
The invention adopts ammonia of decomposition products such as ammonium carbonate, ammonium bicarbonate, ammonium carbamate, urea aqueous solution and the like as an ammonia source, and the ammonia is mixed with gas phase methanol to enter a catalyst which is filled with mordenite, or ZSM-5, HY molecular sieve or SiO 2 -Al 2 O 3 The composition catalyst is fixed bed reactor and methylamine reaction is carried out, the methylamine mixed product, the aqueous vapor and the carbon dioxide enter a gas-liquid reactor which is already put with metering water, and the formation reaction of mixed methylamine carbonate is further completed.
The invention adopts ammonia in thermal decomposition products such as ammonium carbonate, ammonium bicarbonate, ammonium carbamate, urea aqueous solution and the like as an ammonia source to replace liquid ammonia, so that the safety and environmental protection are greatly improved, and the continuous fixed bed catalytic reaction is adopted to prepare the mixed methylamine, so that the invention has the advantages of low reaction pressure, good economy and continuous and controllable production. The mixture of carbon dioxide and methylamine in the decomposition products is then subjected to a salt formation reaction to obtain a mixed methylamine bicarbonate and a mixed methylamine carbonate product. Because the mixed methylamine carbonate solution has the characteristic of easy decomposition, the mixed methylamine carbonate solution can be applied to the foam plastic manufacture of polyurethane and the like.
In particular, because the mixed methylamine (hydrogen) carbonate solution is alkalescent, the mixed methylamine (hydrogen) carbonate is easy to decompose at normal temperature, the mixed methylamine (hydrogen) carbonate solution is subjected to ring opening reaction with ethylene oxide and propylene oxide, and the mixed methylamine (hydrogen) carbonate is further quaternized to prepare a quaternary ammonium (hydrogen) carbonate mixture, and the stability of the quaternary ammonium bicarbonate solution of the mixed methylamine at normal temperature can be effectively improved. The specific reaction is as follows formula (7):
wherein R is methyl, n=1, 2 or 3; r' is H or methyl.
Similarly, the quaternary ammonium (hydrogen) carbonate and quaternary ammonium (hydrogen) carbonate mixture are easy to generate thermal decomposition reaction at the temperature higher than 50 ℃, and based on the characteristic, the quaternary ammonium carbonate salt solution mixed with methylamine can also be applied to the manufacture of polyurethane foam plastics and the like.
The technical scheme of the invention is as follows:
a method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction, which comprises the following steps:
the method comprises the steps of taking decomposed ammonia source compounds as raw materials, obtaining ammonia gas and carbon dioxide through thermal decomposition, generating a methylamine mixture through catalytic reaction of methanol and ammonia gas at a high temperature by a continuous fixed bed, and obtaining mixed methylamine carbonate or/and methylamine bicarbonate through salifying reaction of the methylamine mixture, carbon dioxide and water.
According to the present invention, preferably, the decomposed ammonia source compound is an inorganic ammonium salt or an organic amine compound; further preferably, the inorganic ammonium salt is selected from ammonium carbonate and ammonium bicarbonate, and the organic amine is selected from ammonium carbamate and urea;
preferably, the urea is in the form of an aqueous urea solution having a mass concentration of 40% to a saturated aqueous urea solution, more preferably 45% to 50% aqueous urea solution.
According to the present invention, it is preferable that the thermal decomposition conditions are as follows:
ammonium carbonate, ammonium carbamate or ammonium bicarbonate is thermally decomposed at 70-100 ℃ under 0.35-0.55MPa, more preferably at 80-90 ℃ under 0.35-0.45 MPa;
the urea aqueous solution is decomposed at 145 to 165℃and 0.35 to 0.70MPa, and more preferably at 155 to 165℃and 0.45 to 0.70 MPa.
According to the invention, the catalyst for the continuous fixed bed catalytic reaction is preferably a mordenite catalyst, or ZSM-5, HY molecular sieve or SiO 2 -Al 2 O 3 Composition catalyst.
According to the invention, the continuous fixed bed catalytic reaction conditions are preferably 380-420 ℃, 1.25-1.50 MPa, more preferably 400-410 ℃ and the control pressure is 1.25-1.40 MPa.
According to the invention, preferably, the molar ratio of ammonia gas to methanol is 1: 1-1:1.5, more preferably 1:1 to 1:1.2.
according to the invention, the temperature at which the methylamine mixture is salified with carbon dioxide and water is preferably between 35 and 40℃and the pressure is <0.35MPa.
According to the invention, the methylamine bicarbonate solution is further mixed with an epoxide, such as: the epoxy ethane, epoxy propane or epoxy chloropropane is subjected to ring opening reaction, and the mixed methylamine bicarbonate is quaternized to prepare the mixed methylamine quaternary ammonium bicarbonate salt, so that the stability of the mixed methylamine carbonate solution at normal temperature can be effectively improved.
According to the invention, preferably, the temperature of the ring-opening reaction of the mixed methylamine carbonate quaternary ammonium salt solution and epoxide is 35-60 ℃, and the pressure is less than 0.60MPa;
further preferably, when the epoxide is ethylene oxide, the reaction temperature and pressure are respectively: 35-40 ℃ and <0.35MPa;
when the epoxide is propylene oxide, the reaction temperature and pressure are 55 to 60 ℃ and <0.60MPa.
According to the present invention, since the mixed methylamine carbonate solution has a characteristic of easy decomposition, it can be applied to the production of polyurethane foam, etc. Similarly, mixed quaternary ammonium methylamine carbonate is susceptible to thermal decomposition reaction at a temperature above 50-60 ℃, and based on this characteristic, mixed quaternary ammonium methylamine carbonate can also be applied to foam materials for producing polyurethane.
According to the present invention, there is also provided an apparatus for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction, comprising: the methanol storage tank is connected with the gas phase mixer sequentially through the liquid phase metering pump and the vaporizer, the decomposing device is connected with the gas phase mixer through the mass flowmeter, the gas phase mixer is connected with the top of the fixed bed reactor, the bottom of the fixed bed reactor is connected with the first gas-liquid separator through the back pressure valve, the bottom of the first gas-liquid separator is connected with the gas-liquid reactor through the first liquid compression pump, the top of the first gas-liquid separator is connected with the second gas-liquid separator, the top of the second gas-liquid separator is connected with the gas-liquid reactor through the gas compression pump, and the bottom of the second gas-liquid separator is connected with the gas phase mixer through the second liquid compression pump.
According to the invention, the number of the gas-liquid reactors is preferably two, and the gas-liquid reactors are arranged in parallel. Namely: the bottom of the first gas-liquid separator is connected with the first gas-liquid reactor and the second gas-liquid reactor respectively through a first liquid compression pump, and the top of the second gas-liquid reactor is connected with the first gas-liquid reactor and the second gas-liquid reactor respectively through a gas compression pump.
According to the invention, preferably, the temperature of the first gas-liquid separator is 10℃and the temperature of the second gas-liquid separator is-35 ℃.
According to the present invention, there is also provided a method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction using the above apparatus, comprising the steps of:
after the methanol in the methanol storage tank is gasified by a liquid phase metering pump in a carburetor, the methanol is sent to a gas phase mixer, and is mixed with ammonia source gas phase materials decomposed by a decomposition device and then sent to a fixed bed reactor loaded with a catalyst for methylamine reaction; discharging the methylamine reaction product through a back pressure valve, entering a first gas-liquid separator to separate the mixed methylamine gas-phase product and water from unconverted ammonia gas and carbon dioxide gas, pumping the liquid-phase mixed methylamine/water into a first gas-liquid reactor and a second gas-liquid reactor which are already filled with measured water through a first liquid compression pump to carry out salt forming reaction, separating the unconverted ammonia gas and the carbon dioxide gas again in the second gas-liquid separator, pumping the liquid ammonia serving as return materials into a gas-phase raw material mixer through a second liquid compression pump, and pumping the carbon dioxide gas into the first gas-liquid reactor and the second gas-liquid reactor through a gas compression pump to carry out salt forming reaction.
According to the invention, preferably, the temperature of the metered methanol entering the vaporizer is controlled to be 80-120 ℃, more preferably, the vaporization temperature is controlled to be 85-90 ℃, and further, the gas-phase methanol with the pressure of 0.30-0.40 MPa is formed so as to be conveniently conveyed into the gas-phase mixer; when urea aqueous solution is used as the ammonia decomposition source, the gasification temperature of methanol is controlled to be 110-120 ℃ to form gas-phase methanol with the pressure of 0.60-0.75 MPa so as to be conveniently conveyed into a gas-phase mixer. In particular, when the methanol gas and the ammonia source gas phase are sent into the gas phase mixer, the pressure is adjusted timely so as to facilitate the process cooperation implementation.
The raw materials such as ammonium carbonate, ammonium carbamate or ammonium bicarbonate are subjected to thermal decomposition at 70-100 ℃ and 0.35-0.55MPa by adopting a thermal decomposition kettle, are continuously fed in a gas phase by adopting a mass flowmeter in a two-kettle switching mode, and are fed into a gas phase mixer to be mixed with methanol gas; the urea raw material can be in the form of aqueous solution, and is subjected to catalytic hydrolysis reaction in a decomposing device, wherein the hydrolysis condition is 145-165 ℃, the pressure is 0.35-0.70 MPa, the catalytic urea aqueous solution is rapidly decomposed into ammonia gas and a mixed gas product of carbon dioxide including water vapor, and the mixed gas product is continuously fed in a gas phase by adopting a mass flowmeter and is sent into a gas phase mixer to be mixed with methanol gas.
According to the present invention, preferably, the decomposed ammonia source compound is ammonium carbonate, ammonium carbamate and 40% to urea saturated aqueous solution; the concentration of the urea aqueous solution is preferably 45% -50% urea aqueous solution. The ammonium carbonate and the ammonium carbamate can be decomposed from room temperature, and the complete decomposition temperature is about 120 ℃, so that the reaction balance is almost not existed, and the complete decomposition is easy, thereby being more beneficial to being used as an ammonia source reactant. Preferably, the thermal decomposition conditions of ammonium carbonate and ammonium carbamate are 80-90 ℃ and 0.35-0.45 MPa. The urea aqueous solution with about 50% of the concentration can be rapidly and irreversibly decomposed into ammonia gas and mixed gas products of carbon dioxide including water vapor at 155-165 ℃ and under the pressure of about 0.45-0.70 MPa.
The fixed bed reactor has a plurality of loaded catalysts, and can effectively regulate and control the content of different methylamines in the mixed methylamine through the selection of Si/Al ratios, pore diameters, specific pore volumes and the like of different molecular sieve catalysts. Preferably, large pore size mordenite, H-ZSM-5 or USY molecular sieves or SiO 2 -Al 2 O 3 The composition is used as a catalyst, and the aperture is larger, so that the adsorption of trimethylamine is facilitated, and the mixed methylamine product has higher trimethylamine content.
The gas phase reaction material ammonia, carbon dioxide, water (anhydrous in the case of ammonium carbamate) and methanol (gas) are mixed according to a certain mole ratio, and then are fed into a gas phase mixer to be mixed, and are filled with large-aperture mordenite, or H-ZSM-5, or USY molecular sieve, or SiO 2 -Al 2 O 3 The composition is prepared by controlling a fixed bed reactor at 380-420 ℃ and under the condition of 1.25-1.50 MPa, and reacting ammonia with methanol under the condition to generate monomethylamine, dimethylamine and trimethylamine. The catalyst is preferably large-aperture ZSM-5 and USY molecular sieve, the preferable reaction temperature is 400-410 ℃, and the control pressure is 1.25-1.40 MPa. At this time, the trimethylamine content in the mixed methylamine is about 56% -71%.
When the feeding mole ratio of ammonia to methanol is 1:1-1:1.5, the conversion rate of methanol is high and reaches 85% -99.5%; as the feed molar ratio of ammonia to methanol is changed, the content of each of the methylamines in the mixed methylamine is correspondingly changed; preferably, the molar ratio of ammonia to methanol is 1:1-1: 1.2, the conversion rate of methanol is more than 87%, and the trimethylamine content in the mixed methylamine after exiting the fixed bed reactor FR-1 is more than 56%.
The mixed methylamine and other gas-phase products prepared by the fixed bed reactor are mixed with methylamine, water vapor and carbon dioxide after passing through a back pressure valve, and the mixture is completely reacted with ammonia gas, enters a first gas-liquid separator under the condition of 10 ℃, is condensed and completes the gas-liquid separation of methylamine mixed solution, residual ammonia gas and carbon dioxide, and the condensed water and the mixed methylamine are sent into the gas-liquid reactor; the gas phase residual ammonia and carbon dioxide enter a low-temperature second gas-liquid separator at the temperature of minus 35 ℃, the gas-liquid separation of the residual ammonia and the carbon dioxide is completed after condensation, the liquid ammonia is pumped back to the gas-phase mixer by a first liquid compression pump to participate in the cyclic reaction, and the gas phase carbon dioxide is pumped into the gas-liquid reactor by a gas compression pump to further react to generate the mixed methylamine bicarbonate or the mixed methylamine carbonate. Preferred decomposed ammonia source compounds are ammonium carbonate and ammonium carbamate and-50% aqueous urea solution, the molar ratio of ammonia to carbon dioxide produced by decomposition being 2:1, when the ammonia conversion rate is about 50%, the main product obtained by the reaction of the mixed methylamine and the carbon dioxide is mixed methylamine bicarbonate, and the main product is simply called mixed methylamine carbonate.
The mixed methylamine bicarbonate generating reaction in the gas-liquid reactor is a slow reaction, and because the methylamine mixture takes trimethylamine as a main component, in the aqueous solution with stronger alkalinity, the mixed methylamine and carbon dioxide are easy to react to generate the bicarbonate solution of the mixed methylamine. Preferably, the temperature and pressure of the gas-liquid reactor are controlled as follows: the mixed methylamine carbonate reaction is completed under the process conditions of 35-40 ℃ and <0.35 MPa. Two gas-liquid reactors are arranged in the whole device for switching feeding. And after the gas-liquid reaction is completed, balancing to the pressure of 0.0MPa, and discharging the mixed methylamine carbonate solution material.
The product mixed methylamine bicarbonate solution prepared by the invention can be used for further preparing mixed methylamine carbonate quaternary ammonium bicarbonate solution. Since mixed methylamine bicarbonates are easily decomposed at ordinary temperature, they generally need to be stored at 10℃or lower. The mixed methylamine bicarbonate solution prepared as described above is used in other low pressure reaction apparatus to further react with epoxides such as: the mixed methylamine bicarbonate is quaternized by ring-opening reaction of ethylene oxide, propylene oxide or epichlorohydrin to prepare the mixed methylamine bicarbonate, so that the stability of the mixed methylamine carbonate solution at normal temperature can be effectively improved. Preferably, the epoxide is ethylene oxide, propylene oxide. The mixed methylamine ammonium bicarbonate is called mixed methylamine ammonium carbonate for short.
The specific preparation method of the mixed methylamine carbonate quaternary ammonium salt solution provided by the invention comprises the following steps: controlling a low-pressure reaction device to feed a certain amount of mixed methylamine carbonate solution, water, ethylene oxide or propylene oxide under negative pressure of-0.10 to-0.20 MPa, and then controlling the reaction temperature and the reaction pressure to be respectively: under the process conditions, the mixed methylamine carbonate quaternary ammonium salt solution is prepared by completing the reaction of the mixed methylamine carbonate quaternary ammonium salt at the temperature of 35-40 ℃ and the pressure of <0.35MPa (reaction with ethylene oxide), or at the temperature of 55-60 ℃ and the pressure of <0.60MPa (reaction with propylene oxide).
Similarly, the mixed methylamine carbonate quaternary ammonium salt is easy to generate thermal decomposition reaction at the temperature of more than 50-60 ℃, and based on the characteristic, the mixed methylamine carbonate quaternary ammonium salt can be applied to the foamed plastic material for manufacturing polyurethane. Preferably, the mixed methylamine carbonate quaternary ammonium salt solution is prepared by adopting ethylene oxide or propylene oxide, and can be used for preparing hard foam polyurethane materials with better performance.
The beneficial effects of the invention are as follows:
1. according to the method for preparing the mixed methylamine carbonate in situ through the continuous fixed bed catalytic reaction, provided by the invention, the ammonium carbonate, the ammonium carbamate and the urea aqueous solution thermal decomposition products are not required to be separated, wherein ammonia replaces liquid ammonia to be used as an ammonia source, so that the traditional technical route for preparing methylamine is changed, and the method has remarkable safety and environmental friendliness;
2. the invention provides a method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction, which uses large aperture mordenite, or H-ZSM-5, or USY molecular sieve, or SiO 2 -Al 2 O 3 The composition is a catalyst, the reaction process conditions are high-temperature and low-pressure reactions, and the trimethylamine content in the prepared mixed methylamine is up to more than 56%;
3. according to the method for preparing the mixed methylamine carbonate in situ through the continuous fixed bed catalytic reaction, provided by the invention, the separation of the mixed methylamine/water and unreacted ammonia gas/carbon dioxide is realized through condensation of the product of the fixed bed reactor, and the liquid phase mixed methylamine/water is sent into a gas-liquid reactor; the gas phase is further condensed to separate unreacted ammonia from carbon dioxide, wherein the unreacted ammonia is further reacted as a return material, and the carbon dioxide is sent into a gas-liquid reactor to carry out salt forming reaction with mixed methylamine, so as to prepare the mixed methylamine carbonate. The ammonia and the carbon dioxide with fixed molar compositions are generated by decomposing the ammonium carbonate and other compounds, wherein the carbon dioxide can meet the requirement of preparing the mixed methylamine carbonate, and the additional introduction of carbonic acid gas is not needed, so that the method for preparing the mixed methylamine carbonate is greatly simplified, the production efficiency is improved, and the continuous method is easy to realize in an industrialized mode;
4. According to the method for preparing the mixed methylamine carbonate in situ through the continuous fixed bed catalytic reaction, the prepared mixed methylamine carbonate can be further introduced with ethylene oxide, propylene oxide or the like to perform a base catalytic ring-opening reaction, so that the quaternary ammonium carbonate of the mixed methylamine with better stability at normal temperature is prepared;
5. the method for preparing the mixed methylamine carbonate in situ by the continuous fixed bed catalytic reaction provided by the invention can be used for preparing polyurethane rigid foam materials, especially the quaternary ammonium carbonate mixture prepared by adopting ethylene oxide, and the prepared mixed methylamine carbonate solution and the quaternary ammonium carbonate solution of the mixed methylamine can be used for preparing polyurethane rigid foam materials with better performance, and can have huge environmental benefits if being used as a fluorine-containing chlorofluorocarbon foaming agent substitute.
6. The device for preparing the mixed methylamine carbonate in situ by the continuous fixed bed catalytic reaction has the advantages of simple structure, capability of realizing continuous reaction and easy industrial production.
Drawings
FIG. 1 is a schematic structural diagram of an apparatus for in situ preparation of mixed methylamine carbonate by continuous fixed bed catalytic reaction in example 1;
FIG. 2 is a gas chromatogram of the reaction mixture from the fixed bed reactor in example 2;
FIG. 3 is a gas chromatogram of the reaction mixture from the fixed bed reactor in example 6;
FIG. 4 is a gas chromatogram of the reaction mixture from the fixed bed reactor in example 11;
FIG. 5 is an infrared spectrum of the synthesized product of example 2, mixed methylamine carbonate (A1);
FIG. 6 is an infrared spectrum of a mixed methylamine (isopropyl alcohol) carbonate quaternary ammonium salt (B21) as a synthesized product of example 7;
FIG. 7 is an infrared spectrum of a mixed methylamine (isopropyl alcohol) carbonate quaternary ammonium salt (B22) as a synthesized product of example 8;
FIG. 8 is a photograph showing the appearance of a rigid polyurethane foam plastic prepared by using A1, A2 and A3;
FIG. 9 is a photograph showing the appearance of polyurethane rigid foam plastic bodies prepared by using B3, B4, B5 and B6.
Wherein: v01 methanol storage tank, MP01 liquid phase metering pump, RR01 decomposing device, RH01 vaporizer, MIX01 gas phase mixer, MM01 mass flowmeter, FR01 fixed bed reactor, BP01 back pressure valve, GLS01 first gas-liquid separator, GLS02 second gas-liquid separator, LP01 first liquid compression pump, LP02 second liquid compression pump, CP02 gas compression pump, PR01 first gas-liquid reactor, PR02 second gas-liquid reactor.
Detailed Description
The invention will now be further illustrated by means of specific examples in conjunction with the accompanying drawings without limiting the scope of the invention.
Example 1
As shown in fig. 1, an apparatus for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction comprises: the methanol storage tank V01 and the decomposing device RR01 are sequentially connected with the gas-phase mixer MIX01 through the liquid-phase metering pump MP01 and the vaporizer RH01, the decomposing device RR01 is connected with the gas-phase mixer MIX01 through the mass flowmeter MM01, the gas-phase mixer MIX01 is connected with the top of the fixed bed reactor FR01, the bottom of the fixed bed reactor FR01 is connected with the first gas-liquid separator GLS01 through the back pressure valve BP01, the bottom of the first gas-liquid separator GLS01 is connected with the gas-liquid reactor through the first liquid compression pump LP01, the top of the first gas-liquid separator GLS01 is connected with the second gas-liquid separator GLS02, the top of the second gas-liquid separator GLS02 is connected with the gas-phase mixer MIX01 through the gas compression pump CP02, and the bottom of the second gas-liquid separator GLS02 is connected with the gas-phase mixer MIX01 through the second liquid compression pump LP 02.
In this embodiment, the number of the gas-liquid reactors is two and the gas-liquid reactors are arranged in parallel. Namely: the bottom of the first gas-liquid separator GLS01 is connected with the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02 through a first liquid compression pump LP01, and the top of the second gas-liquid reactor PR02 is connected with the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02 through a gas compression pump CP 02. The decomposing device RR01 is a thermal decomposing reactor.
The temperature of the first gas-liquid separator GLS01 was 10℃and the temperature of the second gas-liquid separator GLS02 was-35 ℃.
Example 2
The mixed methylamine carbonate was prepared using the apparatus for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction as described in example 1, which uses ammonium carbonate salt as ammonia source and hydrogen mordenite as catalyst.
6.410kg of high-purity industrial methanol is placed into a methanol storage tank V01, 9.705kg of industrial ammonium carbonate is placed into a thermal decomposition kettle RR01, the methanol is sent into a gasifier RH01 through a liquid phase metering pump MP01 and gasified at 85 ℃, and the ammonium carbonate is heated at 90-95 ℃ to decompose gas products and is metered through a mass flowmeter MM 01; the mass ratio of methanol to ammonium carbonate decomposing gas feed is controlled to be about 1:1.51 (wherein the molar ratio of N/C is 1:1), methanol gas and ammonium carbonate decomposed gas are fed into a fixed bed reactor FR01 filled with synthetic hydrogen type large-aperture mordenite (low Si/Al value 4.10-6.00, aperture about 0.7nm, zhuo environmental protection technology Co., ltd.) together through a gas phase mixer MIX01, the catalyst is ammoniated in advance and preheated to 410 ℃, and the pressure in the fixed bed reactor FR01 is controlled to be 1.25MPa by a back pressure valve BP 01.
The reaction mixture exiting the fixed bed reactor FR01 enters a first gas-liquid separator GLS01, gas-liquid separation of mixed methylamine and water, residual ammonia and carbon dioxide is completed at the temperature of 10 ℃, and the mixed methylamine aqueous solution is sent into a first gas-liquid reactor PR01 and a second gas-liquid reactor PR02 through a first liquid compression pump LP 01; the gas phase residual ammonia and carbon dioxide enter a low-temperature second gas-liquid separator GLS02 at the temperature of minus 35 ℃, and the liquid ammonia is sent back to a gas-phase mixer MIX01 for cyclic reaction through a second liquid compression pump LP 02; the gaseous carbon dioxide is sent into the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02 through the gas compression pump CP 02.
The reaction mixture exiting the fixed bed reactor FR01 was monitored for the composition of the gas phase product by on-line gas chromatography, thereby effecting control of the mixed methylamine ammonium carbonate solution product. Feeding mixed methylamine and carbon dioxide materials into a first gas-liquid reactor PR01 and a second gas-liquid reactor PR02, simultaneously feeding 1.800kg of water into the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, carrying out salt forming reaction at the temperature of 35-40 ℃ and the pressure of less than 0.35MPa, slowly cooling to below 25 ℃ after the feeding of all materials is finished and the reaction is finished, slowly releasing vacuum at the pressure of approximately 0.00MPa, and removing a small amount of unreacted carbon dioxide to obtain 15.790kg of clear and transparent ammonium carbonate solution of the mixed methylamine, wherein the mass concentration of the ammonium carbonate solution is 53.2 percent and is denoted as A1.
Analysis of the composition of the FR01 product exiting the fixed bed reactor:
the fixed bed reactor product was detected using on-line gas chromatography. The chromatographic conditions were as follows: chromatographic column: (methylamine analytical column gas-filled chromatographic column, specification: 3m x 3mm x 60-80 mesh, maximum use temperature: 200 ℃), instrument conditions: the temperature of the vaporization chamber is 150 ℃, the temperature of the detector TCD is 150 ℃, and the column temperature is 100 ℃; column front pressure: 0.10MPa; sample injection mode: and (5) directly injecting sample and quantifying by an internal standard method. The chromatographic analysis of the product is shown in FIG. 2, and the chromatographic analysis results of each component are shown in Table 1 below.
TABLE 1
| Each component is composed of | Ammonia | Monomethylamine | Dimethylamine | Trimethylamine | Methanol | Water and its preparation method | Totals to |
| Retention time | 1.153 | 2.550 | 4.428 | 5.566 | 7.939 | 10.973 | / |
| Peak area% | 17.381 | 5.952 | 5.403 | 24.057 | 2.652 | 44.536 | 99.981 |
Further calculations indicated by the results of the composition analysis of the FR01 product exiting the fixed bed reactor: under this condition, the conversion rate of methanol is about 93%, the reaction conversion rate of decomposing ammonia is about 41%, and ammonia is separated and recycled to participate in the reaction. (there may be a small amount of dimethyl ether in the product, which may be masked by trimethylamine peaks due to its difficulty in separation from trimethylamine; carbon dioxide does not peak).
Hereinafter, X% is methanol conversion, Y% is decomposed ammonia conversion, S Total (S) For total methylamine selectivity, LHSV is the feed space velocity calculated according to formula (8), formula (9), formula (10) and formula (11), respectively.
Experimental summary of FR01 product analysis by exit from fixed bed reactor the results of this hydrogen mordenite catalyst under this process condition are listed in table 2 below:
TABLE 2
Reaction conditions: t=410 ℃, p=1.25 mpa, lhsv=1.5 h -1 The amount of liquid ammonia returned is about 12.5wt% of the total feed.
EXAMPLE 3 preparation of Mixed methylamine carbonate Quaternary ammonium salt Using the Mixed methylamine carbonate prepared in EXAMPLE 2
The mixed methylamine carbonate prepared in example 2 may be further ring-opened reacted with ethylene oxide to prepare a quaternary ammonium carbonate salt of mixed methylamine. The method comprises the following steps:
Taking 1.000 kg of the carbonate solution A of the mixed methylamine and 0.355kg of water, feeding the mixed methylamine into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.455kg of ethylene oxide, stirring and reacting for 2.5 hours at the temperature of 35-40 ℃ and the pressure of lower than 0.35MPa, continuing to balance under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to below 25 ℃, slowly releasing vacuum when the pressure is close to the balance with the atmospheric pressure, removing a small amount of unreacted ethylene oxide, discharging to obtain 2.800kg of clear transparent quaternary ammonium carbonate salt solution of the mixed methylamine, wherein the mass concentration of the quaternary ammonium carbonate salt solution is 54.0 percent, and the mass concentration is recorded as B1.
Example 4 application of Mixed methylamine ammonium carbonate salt solution A1 in preparation of polyurethane hard foam Plastic
The ammonium carbonate salt solution A1 of the mixed methylamine prepared in the example 2 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
50 parts by weight of polyether polyol 4110 (Jieduda polyurethane Co., ltd.), 10 parts by weight of polyether polyol 403 (Jieduda polyurethane Co., ltd.), 1 part of foam stabilizer SH-493A (Hubei New Sihai chemical Co., ltd.), 5 parts of mixed methylamine ammonium carbonate salt solution A1,0.25 part of cyclohexylamine and 0.005 part of organic tin are uniformly mixed to obtain a uniform and transparent foam composition, and then 61.0 parts of polyisocyanate MDI (Wanhua chemical PM-200) is added thereto, and further uniformly stirred to obtain a polyurethane rigid foam plastic.
Example 5 application of ammonium carbonate salt solution B1 of Mixed methylamine in preparation of polyurethane hard foam Plastic
The quaternary ammonium carbonate salt B1 of the mixed methylamine prepared in the example 3 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
30.0 parts by weight (hereinafter the same) of a polyether polyol 4110 (tabacco to polyurethane Co., ltd.), 15.0 parts by weight of a polyester polyol CF-6320 (Nanjing Kang Sude chemical Co., ltd.), 1.0 parts by weight of a foam stabilizer SH-493A (Hubei New four sea chemical Co., ltd.), 7.0 parts by weight of a quaternary ammonium carbonate salt solution B1 of mixed methylamine, 0.25 parts by weight of cyclohexylamine and 0.005 parts by weight of organotin, and uniformly mixing to obtain a uniform, transparent foam composition, and then 50.0 parts by weight of a polyisocyanate PAPI-27 (Dow in America) was added thereto, and further uniformly stirred to obtain a polyurethane rigid foam.
Example 6
The present example provides a method for preparing carbonate by continuous fixed bed in situ catalytic reaction using ammonium carbonate as ammonia source and large pore size USY molecular sieve as catalyst, the preparation steps are the same as those of example 2, except that:
the fixed bed reactor FR01 is filled with USY molecular sieve (the relative crystallinity is larger than or equal to 90 percent, the low Si/Al value is 5.6 to 6.0, the average pore diameter is about 0.75nm, the Zhuo environmental protection technology Co., ltd.); the dosage of the high-purity industrial methanol is 3.203kg, and the dosage of the industrial ammonium carbonate is 4.850kg; the catalyst in the fixed bed reactor FR01 was ammoniated in advance and preheated to 410℃and the back pressure valve BP01 controlled the pressure in the fixed bed reactor FR01 to 1.25MPa.
After separating unconverted ammonia from reactants exiting the fixed bed reactor FR01, mixing methylamine, carbon dioxide, water and the like, entering the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, simultaneously feeding 0.900kg of water into the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, carrying out salt forming reaction at 35-40 ℃ and a pressure lower than 0.35MPa, slowly reducing the temperature to below 25 ℃ after the feeding of all materials is finished, slowly releasing vacuum at a pressure of approximately 0.00MPa, and removing a small amount of unreacted carbon dioxide to obtain 7.850kg of clear and transparent carbonate solution of the mixed methylamine, wherein the concentration of the carbonate solution is 52.4%, and the concentration is denoted as A2.
Analysis of the composition of the FR01 product exiting the fixed bed reactor:
the fixed bed reactor FR01 product was detected by on-line gas chromatography. Chromatographic conditions were the same as in example 2. The chromatographic analysis of the product is shown in FIG. 3, and the chromatographic analysis results of the components are shown in Table 3 below.
TABLE 3 Table 3
| Each component is composed of | Ammonia | Monomethylamine | Dimethylamine | Trimethylamine | Methanol | Water and its preparation method | Totals to |
| Retention time | 1.154 | 2.550 | 4.429 | 5.567 | 7.939 | 10.972 | / |
| Peak area% | 18.920 | 4.971 | 4.576 | 23.375 | 4.690 | 43.421 | 99.954 |
Further calculations indicated by the results of the composition analysis of the FR01 product exiting the fixed bed reactor: under this condition, the conversion rate of methanol is about 90%, the reaction conversion rate of decomposing ammonia is about 38%, and ammonia is separated and recycled to participate in the reaction.
Experimental summary of FR01 product analysis by a fixed bed reactor the results of this large pore USY molecular sieve catalyst under this process condition are presented in table 4 below:
TABLE 4 Table 4
Reaction conditions: t=410 ℃, p=1.25 mpa, lhsv=1.5 h -1 The amount of liquid ammonia returned was about 13.1wt% of the total feed.
Example 7
The mixed methylamine carbonate solution A2 prepared in example 6 may be further subjected to ring-opening reaction with ethylene oxide to prepare a mixed methylamine carbonate quaternary ammonium salt. The method comprises the following steps:
taking 2.000kg of the carbonate solution A2 of the mixed methylamine prepared in the example 6 and 0.360kg of water, feeding the mixed methylamine into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.430kg of ethylene oxide, stirring and reacting for 2.5 hours at the temperature of 35-40 ℃ and the pressure of lower than 0.35MPa, continuously balancing under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to below 25 ℃, slowly releasing vacuum when the pressure is close to the balance with the atmospheric pressure, removing a small amount of unreacted ethylene oxide, and discharging to obtain 2.780kg of clear and transparent quaternary ammonium carbonate solution of the mixed methylamine, wherein the concentration of the quaternary ammonium carbonate solution is 53.0 percent and is denoted as B21.
Example 8
The mixed methylamine carbonate solution A2 prepared in example 6 may be further subjected to ring-opening reaction with propylene oxide to prepare a mixed methylamine carbonate quaternary ammonium salt. The specific preparation reaction process is as follows:
Taking 2.000kg of the mixed methylamine carbonate solution A2 prepared in the example 6 and 0.460kg of water, feeding the mixed methylamine carbonate solution A2 into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.565kg of propylene oxide, stirring and reacting for 5.5 hours at the temperature of 55-60 ℃ and the pressure of lower than 0.60MPa, continuing to balance under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to about 45 ℃, removing a small amount of unreacted propylene oxide under the pressure of 80kPa, slowly releasing vacuum, and discharging to obtain 3.020kg of milky white slightly turbid mixed methylamine carbonate quaternary ammonium salt solution with the concentration of 53.3 percent and denoted as B22.
Example 9 application of Mixed methylamine ammonium carbonate salt solution in preparation of polyurethane hard foam Plastic
The carbonate solution A2 of the mixed methylamine prepared in the example 6 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
50 parts by weight of polyether polyol 4110 (Kazak Shuda polyurethane Co., ltd.), 10 parts by weight of polyether polyol 403 (Kazak Shuda polyurethane Co., ltd.), 1 part of foam stabilizer SH-493A (Hubei New Sihai chemical Co., ltd.), 5 parts of A2 solution, 0.25 part of cyclohexylamine and 0.005 part of organotin were uniformly mixed to obtain a uniform, transparent foam composition, and then 61.0 parts of polyisocyanate MDI (Wanhua chemical PM-200) was added thereto, followed by further uniformly stirring to obtain a polyurethane rigid foam.
Example 10 application of ammonium carbonate salt solution of Mixed methylamine to preparation of polyurethane hard foam Plastic
The quaternary ammonium carbonate salt solutions B21 and B22 of the mixed methylamine prepared in the examples 7 and 8 are applied to the preparation of polyurethane hard foam plastics, and the preparation method specifically comprises the following steps:
30.0 parts by weight (hereinafter the same) of a polyether polyol 4110 (Kazak Seda polyurethane Co., ltd.), 15.0 parts by weight of a polyester polyol CF-6320 (Nanjing Kang Sude chemical Co., ltd.), 1.0 parts by weight of a foam stabilizer SH-493A (Hubei New Sihai chemical Co., ltd.), 7.0 parts by weight of a B21 or B22 solution, 0.25 parts by weight of cyclohexylamine and 0.005 parts by weight of organotin were uniformly mixed to obtain a uniform, transparent foam composition, and then 50.0 parts by weight of a polyisocyanate PAPI-27 (Dow in America) was added thereto, and further uniformly stirred to prepare a polyurethane rigid foam.
Example 11
The present example provides a method for preparing carbonate by continuous fixed bed in situ catalytic reaction using ammonium carbonate as ammonia source and H-type ZSM-5 molecular sieve as catalyst, the preparation steps are the same as those of example 2, except that:
the fixed bed reactor FR01 is filled with H-type ZSM-5 molecular sieve (relative crystallinity >95%, low Si/Al value 12.4, average pore diameter about 0.55-0.60nm, zhuoran environmental protection technology Co., ltd.); the dosage of the high-purity industrial methanol is 4.270kg, and the dosage of the industrial ammonium carbonate is 6.470kg; the catalyst in the fixed bed reactor FR01 was ammoniated in advance and preheated to 400℃and BP01 controlled the pressure in the fixed bed reactor FR01 to 1.30MPa.
After separating unconverted ammonia from reactants discharged from the fixed bed reactor FR01, mixing methylamine, carbon dioxide, water and the like, entering the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, simultaneously feeding 1.200kg of water into the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, carrying out salt forming reaction at the temperature of 35-40 ℃ and the pressure of less than 0.35MPa, slowly reducing the temperature to below 25 ℃ after the completion of the feeding of all materials, slowly releasing vacuum at the pressure of approximately 0.00MPa, and removing a small amount of unreacted carbon dioxide to obtain 10.410kg of clear and transparent ammonium carbonate salt solution of the mixed methylamine, wherein the mass concentration of the ammonium carbonate salt solution is 51.5%, and the mass concentration is denoted as A3.
Analysis of the composition of the FR01 product exiting the fixed bed reactor:
the fixed bed reactor product was detected using on-line gas chromatography. Chromatographic conditions were the same as in example 2. The chromatographic analysis of the product is shown in FIG. 4, and the chromatographic analysis results of the components are shown in Table 5 below.
TABLE 5
| Each component is composed of | Ammonia | Monomethylamine | Dimethylamine | Trimethylamine | Methanol | Water and its preparation method | Totals to |
| Retention time | 1.156 | 2.551 | 4.431 | 5.570 | 7.941 | 10.973 | / |
| Peak area% | 18.859 | 3.682 | 9.154 | 20.847 | 5.078 | 42.366 | 99.987 |
Further calculations indicated by the results of the composition analysis of the FR01 product exiting the fixed bed reactor: under this condition, the conversion rate of methanol is about 87%, the reaction conversion rate of decomposing ammonia is about 36%, and ammonia is separated and recycled to participate in the reaction.
Experimental summary of FR01 product analysis from fixed bed reactor the results of this H-type ZSM-5 molecular sieve catalyst under this process condition are shown in table 6 below:
TABLE 6
Reaction conditions: t=400 ℃, p=1.30 mpa, lhsv=1.5 h -1 The amount of liquid ammonia returned was about 13.6wt% of the total feed.
Example 12 preparation of Quaternary ammonium carbonate of Mixed methylamine Using Mixed methylamine carbonate
The ammonium carbonate of mixed methylamine prepared in example 11 may be further ring-opened reacted with ethylene oxide to prepare a quaternary ammonium carbonate of mixed methylamine. The method comprises the following steps:
taking 2.000kg of the carbonate solution A3 of the mixed methylamine prepared in the example 11 and 0.260kg of water, feeding the mixed methylamine into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.405kg of ethylene oxide, stirring and reacting for 2.5 hours at the temperature of 35-40 ℃ and the pressure of lower than 0.35MPa, continuing to balance under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to below 25 ℃, slowly releasing vacuum when the pressure is close to the balance with the atmospheric pressure, removing a small amount of unreacted ethylene oxide, discharging to obtain 2.660kg of clear and transparent quaternary ammonium carbonate solution of the mixed methylamine, wherein the concentration of the clear and transparent quaternary ammonium carbonate solution is 53.8 percent and is denoted as B3.
Example 13 use of Mixed methylamine carbonate solution for the preparation of polyurethane hard foam plastics
The mixed methylamine ammonium carbonate salt solution A3 prepared in the example 11 is applied to the preparation of polyurethane hard foam plastic, and the preparation method specifically comprises the following steps:
50 parts by weight of polyether polyol 4110 (Jieduda polyurethane Co., ltd.), 10 parts by weight of polyether polyol 403 (Jieduda polyurethane Co., ltd.), 1 part of foam stabilizer SH-493A (Hubei New Sihai chemical Co., ltd.), 5 parts of ammonium carbonate salt solution A3 of mixed methylamine, 0.25 part of cyclohexylamine and 0.005 part of organic tin are uniformly mixed to obtain a uniform and transparent foam composition, and then 61.0 parts of polyisocyanate MDI (Wanhua chemical PM-200) is added thereto, followed by further uniformly stirring to obtain a polyurethane rigid foam plastic.
Example 14 use of a mixed methylamine Quaternary ammonium carbonate salt solution for the preparation of polyurethane hard foam plastics
The quaternary ammonium carbonate solution B3 of the mixed methylamine prepared in the example 12 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
30.0 parts by weight (hereinafter the same) of a polyether polyol 4110 (Kazak Shuida polyurethane Co., ltd.), 15.0 parts by weight of a polyester polyol CF-6320 (Nanjing Kang Sude chemical Co., ltd.), 1.0 parts by weight of a foam stabilizer SH-493A (Hubei New four sea chemical Co., ltd.), 7.0 parts by weight of a quaternary ammonium carbonate B3 of methylamine mixed with 0.25 parts by weight of cyclohexylamine and 0.005 parts by weight of organotin, and uniformly mixing to obtain a uniform and transparent foam composition, and then 50.0 parts by weight of a polyisocyanate PAPI-27 (Dow in America) was added thereto, followed by further uniformly stirring to obtain a polyurethane rigid foam.
Example 15
This example provides an ammonium carbonate salt as an ammonia sourceIn the form of SiO 2 -Al 2 O 3 The composition is used as a catalyst, and the method for preparing carbonate by adopting the continuous fixed bed in-situ catalytic reaction is the same as in example 2, except that:
FR01 of the fixed bed reactor is filled with SiO 2 -Al 2 O 3 Composition (cylindrical 5X 5mm particles, siO) 2 /Al 2 O 3 The weight ratio is 22/78, the specific surface area is 306m 2 /g, specific pore volume of 0.89mL/g, homemade); the dosage of the high-purity industrial methanol is 2.565kg, and the dosage of the industrial ammonium carbonate is 3.880kg; the catalyst in the fixed bed reactor FR01 was ammoniated in advance and preheated to 410℃and the back pressure valve BP01 controlled the pressure in the fixed bed reactor FR01 to 1.40MPa.
After separating unconverted ammonia from reactants exiting the fixed bed reactor FR01, mixing methylamine, carbon dioxide, water and the like, entering the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, simultaneously feeding 1.120kg of water into the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, carrying out salt forming reaction at the temperature of 35-40 ℃ and the pressure of less than 0.35MPa, slowly reducing the temperature to below 25 ℃ after the completion of the feeding of all materials, slowly releasing vacuum at the pressure of approximately 0.00MPa, and removing a small amount of unreacted carbon dioxide to obtain 6.780kg of clear and transparent ammonium carbonate salt solution of the mixed methylamine, wherein the concentration of the ammonium carbonate salt solution is 51.4%, and the concentration is denoted as A4.
Analysis of the composition of the FR01 product exiting the fixed bed reactor:
the fixed bed reactor FR01 product was detected by on-line gas chromatography. Chromatographic conditions were the same as in example 2. The chromatographic analysis results of the respective components are shown in Table 7 below.
TABLE 7
| Each component is composed of | Ammonia | Monomethylamine | Dimethylamine | Trimethylamine | Methanol | Water and its preparation method | Totals to |
| Retention time | 1.155 | 2.550 | 4.430 | 5.570 | 7.940 | 10.971 | / |
| Peak area% | 15.950 | 7.317 | 8.486 | 21.616 | 0.531 | 46.088 | 99.988 |
Further calculations indicated by the results of the composition analysis of the FR01 product exiting the fixed bed reactor: under this condition, the conversion rate of methanol is about 98.6%, the reaction conversion rate of decomposing ammonia is about 45.6%, and the ammonia is separated and recycled to participate in the reaction.
Experimental summary evaluation of FR01 product analysis by exit from a fixed bed reactor, whichSiO 2 -Al 2 O 3 The results of the composition catalyst under this process condition are listed in table 8 below:
TABLE 8
Reaction conditions: t=410 ℃, p=1.40 mpa, lhsv=1.5 h -1 The amount of liquid ammonia returned is about 11.5wt% of the total feed.
Example 16 preparation of quaternary ammonium carbonate of mixed methylamine using mixed methylamine carbonate:
the carbonate of mixed methylamine prepared in example 15 may be further ring-opened reacted with ethylene oxide to prepare a quaternary ammonium carbonate of mixed methylamine. The method comprises the following steps:
taking 2.000kg of the carbonate solution A4 of the mixed methylamine and 0.470kg of water, feeding the mixed methylamine into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.475kg of ethylene oxide, stirring and reacting for 2.5 hours at the temperature of 35-40 ℃ and the pressure of lower than 0.35MPa, continuing to balance under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to below 25 ℃, slowly releasing vacuum when the pressure is close to the balance with the atmospheric pressure, removing a small amount of unreacted ethylene oxide, discharging to obtain 2.940kg of clear transparent quaternary ammonium carbonate solution of the mixed methylamine, wherein the concentration of the quaternary ammonium carbonate solution is 51.0 percent, and the concentration is recorded as B4.
Example 17 use of Mixed methylamine carbonate solution for preparing polyurethane hard foam plastics
The carbonate solution A4 of the mixed methylamine prepared in example 15 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
50 parts by weight of polyether polyol 4110 (Jieduda polyurethane Co., ltd.), 10 parts by weight of polyether polyol 403 (Jieduda polyurethane Co., ltd.), 1 part of foam stabilizer SH-493A (Hubei New Sihai chemical Co., ltd.), 5 parts of ammonium carbonate salt solution A4 of mixed methylamine, 0.25 part of cyclohexylamine and 0.005 part of organic tin are uniformly mixed to obtain a uniform and transparent foam composition, and then 61.0 parts of polyisocyanate MDI (Wanhua chemical PM-200) is added thereto, followed by further uniformly stirring to obtain a polyurethane rigid foam plastic.
Example 18 use of a mixed methylamine with a quaternary ammonium carbonate solution for the preparation of polyurethane hard foam plastics
The quaternary ammonium carbonate solution B4 of the mixed methylamine prepared in the example 16 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
30.0 parts by weight (hereinafter the same) of a polyether polyol 4110 (Kazak Shuida polyurethane Co., ltd.), 15.0 parts by weight of a polyester polyol CF-6320 (Nanjing Kang Sude chemical Co., ltd.), 1.0 parts by weight of a foam stabilizer SH-493A (Hubei New four sea chemical Co., ltd.), 7.0 parts by weight of a quaternary ammonium carbonate salt B4 of methylamine, 0.25 parts by weight of cyclohexylamine and 0.005 parts by weight of organotin were uniformly mixed to obtain a uniform and transparent foam composition, and then 50.0 parts by weight of a polyisocyanate PAPI-27 (Dow in America) was added thereto, and further uniformly stirred to prepare a polyurethane rigid foam.
Example 19
This example provides a process wherein ammonia in the thermal decomposition product of ammonium carbamate is used as an ammonia source, and SiO 2 -Al 2 O 3 The composition is used as a catalyst, and the method for preparing carbonate by adopting the continuous fixed bed in-situ catalytic reaction is the same as in example 2, except that:
FR01 of the fixed bed reactor is filled with SiO 2 -Al 2 O 3 Composition (same as in example 15); the dosage of the high-purity industrial methanol is 2.565kg, and the dosage of the industrial grade ammonium carbamate (99%) is 3.154kg; the catalyst in the fixed bed reactor FR01 was ammoniated in advance and preheated to 410℃and the back pressure valve BP01 controlled the pressure in the fixed bed reactor FR01 to 1.40MPa.
Separating unconverted ammonia from reactants exiting the fixed bed reactor FR01, mixing methylamine, carbon dioxide, water and the like, entering the reaction kettle PR03-1, simultaneously feeding 1.720kg of water into the reaction kettle PR03-1, carrying out salifying reaction at the temperature of 35-40 ℃ and the pressure of less than 0.35MPa, slowly reducing the temperature to below 25 ℃ after the feeding of all materials is finished and the reaction is finished, slowly releasing vacuum at the pressure of approximately 0.00MPa, and removing a small amount of unreacted carbon dioxide to obtain 6.670kg of clear and transparent ammonium carbonate salt solution of the mixed methylamine, wherein the mass concentration of the ammonium carbonate salt solution is 52.5 percent and is recorded as A5.
Analysis of the composition of the FR01 product exiting the fixed bed reactor:
The fixed bed reactor FR01 product was detected by on-line gas chromatography. Chromatographic conditions were the same as in example 2. The chromatographic analysis results of the respective components are shown in Table 9 below.
TABLE 9
| Each component is composed of | Ammonia | Monomethylamine | Dimethylamine | Trimethylamine | Methanol | Water and its preparation method | Totals to |
| Retention time | 1.155 | 2.550 | 4.430 | 5.570 | 7.940 | 10.971 | / |
| Peak area% | 18.731 | 8.738 | 10.135 | 25.640 | 0.224 | 36.530 | 99.998 |
Further calculations indicated by the results of the composition analysis of the FR01 product exiting the fixed bed reactor: under this condition, the conversion rate of methanol is about 99.5%, the reaction conversion rate of decomposing ammonia is about 46.0%, and the ammonia is separated and recycled to participate in the reaction.
Experimental summary evaluation of FR01 product analysis by exiting fixed bed reactor, siO 2 -Al 2 O 3 The results of the composition catalyst under this process condition are set forth in Table 10 below:
table 10
Reaction conditions: t=410 ℃, p=1.40 mpa, lhsv=1.5 h -1 The amount of liquid ammonia returned was about 12.9wt% of the total feed.
Example 20 preparation of mixed methylamine quaternary ammonium carbonate salt using mixed methylamine carbonate:
the carbonate of mixed methylamine prepared in example 19 may be further ring-opened reacted with ethylene oxide to prepare a quaternary ammonium carbonate of mixed methylamine. The method comprises the following steps:
taking 2.000kg of ammonium carbonate salt A5 aqueous solution of the mixed methylamine and 0.450kg of water, feeding the mixed methylamine into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.490kg of ethylene oxide, stirring and reacting for 2.5 hours at the temperature of 35-40 ℃ and the pressure of lower than 0.35MPa, continuing to balance under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to below 25 ℃, slowly releasing vacuum when the pressure is close to the balance with the atmospheric pressure, removing a small amount of unreacted ethylene oxide, discharging to obtain 2.930kg of clear and transparent mixed methylamine ammonium carbonate aqueous solution with the mass concentration of 52.3 percent and denoted as B5.
Example 21 use of Mixed methylamine carbonate solution for the preparation of polyurethane hard foam plastics
The carbonate solution A5 of the mixed methylamine prepared in example 19 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
50 parts by weight of polyether polyol 4110 (Jieduda polyurethane Co., ltd.), 10 parts by weight of polyether polyol 403 (Jieduda polyurethane Co., ltd.), 1 part of foam stabilizer SH-493A (Hubei New Sihai chemical Co., ltd.), 5 parts of ammonium carbonate salt solution A5 of mixed methylamine, 0.25 part of cyclohexylamine and 0.005 part of organic tin are uniformly mixed to obtain a uniform and transparent foam composition, and then 61.0 parts of polyisocyanate MDI (Wanhua chemical PM-200) is added thereto, followed by further uniformly stirring to obtain a polyurethane rigid foam plastic.
Example 22 use of a mixed methylamine with a quaternary ammonium carbonate solution for the preparation of polyurethane hard foam plastics
The quaternary ammonium carbonate salt solution B5 of the mixed methylamine prepared in the example 20 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows:
30.0 parts by weight (hereinafter the same) of a polyether polyol 4110 (Kazak Shuida polyurethane Co., ltd.), 15.0 parts by weight of a polyester polyol CF-6320 (Nanjing Kang Sude chemical Co., ltd.), 1.0 parts by weight of a foam stabilizer SH-493A (Hubei New four sea chemical Co., ltd.), 7.0 parts by weight of a quaternary ammonium carbonate salt B5 of methylamine mixed with 0.25 parts by weight of cyclohexylamine and 0.005 parts by weight of organotin, and uniformly mixing to obtain a uniform and transparent foam composition, and then 50.0 parts by weight of a polyisocyanate PAPI-27 (Dow in America) was added thereto, followed by further uniformly stirring to obtain a polyurethane rigid foam.
Example 23
This example provides a catalytic hydrolysis of 50% aqueous urea in a urea catalytic hydrolysis reactor with ammonia in the gas phase product as the ammonia source and SiO 2 -Al 2 O 3 The composition is used as a catalyst and is prepared by adopting a continuous fixed bed in-situ catalytic reactionThe preparation procedure of the preparation of the quaternary ammonium carbonate was the same as in example 2, except that:
FR01 of the fixed bed reactor is filled with SiO 2 -Al 2 O 3 Composition (same as in example 15); the high-purity industrial methanol is 3.200kg, 6.010kg of urea aqueous solution with the weight percentage of 50 percent is subjected to catalytic hydrolysis in a decomposing device RR01, and gas-phase products are fed; the catalyst in the fixed bed reactor FR01 was ammoniated in advance and preheated to 410℃and the back pressure valve BP01 controlled the pressure in the fixed bed reactor FR01 to 1.40MPa.
After the unconverted ammonia is separated from the reactant which is discharged from the fixed bed reactor FR01, the mixed methylamine, carbon dioxide, water and the like enter the first gas-liquid reactor PR01 and the second gas-liquid reactor PR02, and the water content in the gas phase product of the urea hydrolysis reaction can reach 35 weight percent, so that the gas phase product is accompanied with water to sufficiently dilute the mixed methylamine solution. And (3) carrying out salt forming reaction at 35-40 ℃ and under the pressure of less than 0.35MPa, after the whole material feeding is finished and the reaction is finished, slowly cooling to below 25 ℃, slowly releasing vacuum at the pressure of about 0.00MPa, and removing a small amount of unreacted carbon dioxide to obtain 8.290kg of clear and transparent ammonium carbonate salt solution of mixed methylamine, wherein the mass concentration of the ammonium carbonate salt solution is 52.8%, and the ammonium carbonate salt solution is denoted as A6.
Analysis of the composition of the FR01 product exiting the fixed bed reactor:
the fixed bed reactor FR01 product was detected by on-line gas chromatography. Chromatographic conditions were the same as in example 2. The chromatographic analysis results of the respective components are shown in Table 11 below.
TABLE 11
| Each component is composed of | Ammonia | Monomethylamine | Dimethylamine | Trimethylamine | Methanol | Water and its preparation method | Totals to |
| Retention time | 1.155 | 2.550 | 4.430 | 5.570 | 7.940 | 10.971 | / |
| Peak area% | 13.096 | 6.283 | 7.190 | 17.630 | 0.220 | 55.521 | 99.940 |
Further calculations indicated by the results of the composition analysis of the FR01 product exiting the fixed bed reactor: under this condition, the conversion rate of methanol is about 99.3%, the reaction conversion rate of decomposing ammonia is about 46.2%, and the ammonia is separated and recycled to participate in the reaction.
Experimental summary evaluation of FR01 product analysis by exiting fixed bed reactor, siO 2 -Al 2 O 3 The results of the composition catalyst under the process conditions are set forth in the following table12：
Table 12
Reaction conditions: t=410 ℃, p=1.40 mpa, lhsv=1.5 h -1 The amount of liquid ammonia returned was about 9.9wt% of the total feed.
EXAMPLE 24 preparation of Quaternary ammonium carbonate of Mixed methylamine Using Mixed methylamine carbonate
The ammonium carbonate salt of mixed methylamine prepared in example 23 may be further ring-opened reacted with ethylene oxide to prepare a quaternary ammonium carbonate salt of mixed methylamine. The method comprises the following steps:
taking 2.000kg of the mixed methylamine carbonate solution A6 prepared in the example 23 and 0.480kg of water, feeding the mixed methylamine carbonate solution A6 into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.492kg of ethylene oxide, stirring and reacting for 2.5 hours at the temperature of 35-40 ℃ and the pressure of lower than 0.35MPa, continuing to balance under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to below 25 ℃, slowly releasing vacuum when the pressure is close to the balance with the atmospheric pressure, removing a small amount of unreacted ethylene oxide, and discharging to obtain 2.970kg of clear and transparent mixed methylamine quaternary ammonium carbonate solution with the mass concentration of 52.0 percent and denoted as B61.
EXAMPLE 25,
Similarly, the mixed methylamine carbonate salt prepared in example 23 may be further subjected to ring-opening reaction with propylene oxide to prepare a quaternary ammonium carbonate salt of mixed methylamine. The specific preparation reaction process is as follows:
taking 2.000kg of the mixed methylamine carbonate solution A6 prepared in the example 23 and 0.600kg of water, feeding the mixed methylamine carbonate solution A6 into another 5.0L low-pressure reaction kettle under the negative pressure condition of minus 0.2MPa, gradually feeding 0.650kg of propylene oxide, stirring and reacting for 5.5 hours at the temperature of 55-60 ℃ and the pressure of lower than 0.60MPa, continuing to balance under the condition until the pressure is about 0.0MPa, stopping the reaction, slowly reducing the temperature to about 45 ℃, removing a small amount of unreacted propylene oxide under the pressure of 80kPa, slowly releasing vacuum, discharging to obtain 3.245kg of milky white slightly turbid mixed methylamine carbonate quaternary ammonium salt solution with the mass concentration of 52.4 percent and recording as B62.
Example 26 use of Mixed methylamine carbonate solution for the preparation of polyurethane hard foam plastics
The carbonate solution A6 of the mixed methylamine prepared in example 23 is applied to the preparation of polyurethane hard foam plastic, and the preparation method is as follows: 50 parts by weight of polyether polyol 4110 (Jieduda polyurethane Co., ltd.), 10 parts by weight of polyether polyol 403 (Jieduda polyurethane Co., ltd.), 1 part of foam stabilizer SH-493A (Hubei New Sihai chemical Co., ltd.), 5 parts of ammonium carbonate salt solution A6 of mixed methylamine, 0.25 part of cyclohexylamine and 0.005 part of organic tin are uniformly mixed to obtain a uniform and transparent foam composition, and then 61.0 parts of polyisocyanate MDI (Wanhua chemical PM-200) is added thereto, followed by further uniformly stirring to obtain a polyurethane rigid foam plastic.
Example 27 use of quaternary ammonium carbonate solution of mixed methylamine for the preparation of polyurethane rigid foam plastics:
the quaternary ammonium carbonate salt solutions B61 and B62 of the mixed methylamine prepared in the examples 24 and 25 are applied to the preparation of polyurethane hard foam plastics, and the preparation method specifically comprises the following steps:
30.0 parts by weight (hereinafter the same) of a polyether polyol 4110 (Kazak Seda polyurethane Co., ltd.), 15.0 parts by weight of a polyester polyol CF-6320 (Nanjing Kang Sude chemical Co., ltd.), 1.0 parts by weight of a foam stabilizer SH-493A (Hubei New four sea chemical Co., ltd.), 7.0 parts by weight of a quaternary ammonium carbonate salt B61 or B62 of mixed methylamine, 0.25 parts by weight of cyclohexylamine and 0.005 parts by weight of organotin, and uniformly mixing to obtain a uniform, transparent foam composition, and then adding 50.0 parts by weight of a polyisocyanate PAPI-27 (Dow in America) thereto, and further uniformly stirring to obtain a polyurethane rigid foam.
In order to better solve the specific effects of the mixed methylamine carbonate solution prepared by the invention and the application of the mixed methylamine quaternary ammonium carbonate solution in preparing polyurethane hard foam plastics, a comparative experiment for preparing polyurethane hard foam plastics by 141B is carried out according to the same polyurethane hard foam formula.
Comparative example 1:
the black material was polyisocyanate MDI (vancomic PM-200) with polyether 4110/403 combination, and the preparation of polyurethane rigid foam with 141B was compared with the various foaming systems described above, as follows:
The foaming agent 141B is used for preparing the polyurethane hard foam plastic, the preparation method is the same as the application of the mixed methylamine carbonate solution to prepare the polyurethane hard foam plastic in the embodiment 4, the 141B dosage is 12 parts, and the prepared polyurethane hard foam plastic is marked as C.
Comparative example 2:
the black material was polyisocyanate MDI (vancomic PM-200) with polyether 4110/403 combination, and the preparation of polyurethane rigid foam with 141B was compared with the various foaming systems described above, as follows:
the foaming agent 141B is used for preparing the polyurethane hard foam plastic, the preparation method is the same as the application of the mixed methylamine carbonate quaternary ammonium salt solution in the preparation of the polyurethane hard foam plastic in the embodiment 5, the 141B dosage is 12 parts, and the prepared polyurethane hard foam plastic is marked as D.
The properties of the polyurethane rigid foam prepared above are shown in Table 13 below:
TABLE 13
As can be seen from Table 13, the specific effect of the mixed methylamine carbonate solution and the mixed methylamine quaternary ammonium carbonate solution prepared by the invention in the preparation of polyurethane rigid foam plastic is obviously better than that of the existing foam materials.
Claims (10)
1. A method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction, which comprises the following steps:
the method comprises the steps of taking decomposed ammonia source compounds as raw materials, obtaining ammonia gas and carbon dioxide through thermal decomposition, generating a methylamine mixture through catalytic reaction of methanol and ammonia gas at a high temperature by a continuous fixed bed, and obtaining mixed methylamine carbonate or/and methylamine bicarbonate through salifying reaction of the methylamine mixture, carbon dioxide and water.
2. The method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction as claimed in claim 1, wherein the decomposed ammonia source compound is inorganic ammonium salt or organic amine compound;
preferably, the inorganic ammonium salt is selected from ammonium carbonate and ammonium bicarbonate, and the organic amine is selected from ammonium carbamate and urea;
preferably, the urea is in the form of an aqueous urea solution having a mass concentration of 40% to a saturated aqueous urea solution, more preferably 45% to 50% aqueous urea solution.
3. The method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction as claimed in claim 2, wherein the thermal decomposition conditions are as follows: performing thermal decomposition on ammonium carbonate, ammonium carbamate or ammonium bicarbonate at 70-100 ℃ and 0.35-0.55 MPa; decomposing urea aqueous solution at 145-165 ℃ and 0.35-0.70 MPa;
preferably, the catalytic reaction condition of the continuous fixed bed is 380-420 ℃ and 1.25-1.50 MPa;
preferably, the molar ratio of ammonia gas to methanol is 1:1-1:1.5;
preferably, the temperature of the salification reaction of the methylamine mixture with carbon dioxide and water is 35-40 ℃ and the pressure is less than 0.35MPa.
4. The method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction as claimed in claim 1, wherein the mixed methylamine bicarbonate solution is further subjected to ring opening reaction with epoxide, and the mixed methylamine bicarbonate is quaternized to prepare the mixed methylamine carbonate quaternary ammonium bicarbonate.
5. The method for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction as claimed in claim 4, wherein the temperature of ring-opening reaction of mixed methylamine carbonate quaternary ammonium salt solution and epoxide is 35-60 ℃, and the pressure is less than 0.60MPa;
preferably, when the epoxide is ethylene oxide, the reaction temperature and pressure are respectively: 35-40 ℃ and <0.35MPa;
when the epoxide is propylene oxide, the reaction temperature and pressure are 55 to 60 ℃ and <0.60MPa.
6. Use of the mixed methylamine carbonate solution prepared in claim 1 in the manufacture of polyurethane foam.
7. Use of the mixed quaternary ammonium methylamine carbonate prepared in claim 4 in the manufacture of a foamed plastics material for polyurethane.
8. An apparatus for in situ preparation of mixed methylamine carbonate by continuous fixed bed catalytic reaction, comprising: the methanol storage tank is connected with the gas phase mixer sequentially through the liquid phase metering pump and the vaporizer, the decomposing device is connected with the gas phase mixer through the mass flowmeter, the gas phase mixer is connected with the top of the fixed bed reactor, the bottom of the fixed bed reactor is connected with the first gas-liquid separator through the back pressure valve, the bottom of the first gas-liquid separator is connected with the gas-liquid reactor through the first liquid compression pump, the top of the first gas-liquid separator is connected with the second gas-liquid separator, the top of the second gas-liquid separator is connected with the gas-liquid reactor through the gas compression pump, and the bottom of the second gas-liquid separator is connected with the gas phase mixer through the second liquid compression pump.
9. The device for preparing mixed methylamine carbonate in situ by continuous fixed bed catalytic reaction as claimed in claim 8, wherein the number of the gas-liquid reactors is two and the reactors are arranged in parallel;
preferably, the temperature of the first gas-liquid separator is 10 ℃, and the temperature of the second gas-liquid separator is-35 ℃.
10. A method for in situ preparation of mixed methylamine carbonates by continuous fixed bed catalytic reaction using the apparatus of claim 8 or 9, comprising the steps of:
after the methanol in the methanol storage tank is gasified by a liquid phase metering pump in a carburetor, the methanol is sent to a gas phase mixer, and is mixed with ammonia source gas phase materials decomposed by a decomposition device and then sent to a fixed bed reactor loaded with a catalyst for methylamine reaction; discharging methylamine reaction products through a back pressure valve, entering a first gas-liquid separator to separate gas-liquid separation of mixed methylamine gas-phase products and water from unconverted ammonia gas and carbon dioxide gas, pumping the liquid-phase mixed methylamine/water into a first gas-liquid reactor and a second gas-liquid reactor which are already filled with measured water through a first liquid compression pump to carry out salt forming reaction, carrying out gas-liquid separation again on unconverted ammonia gas and carbon dioxide gas in the second gas-liquid separator, pumping liquid ammonia serving as return materials into a gas-phase raw material mixer through a second liquid compression pump, and pumping carbon dioxide gas into the first gas-liquid reactor and the second gas-liquid reactor through a gas compression pump to carry out salt forming reaction;
Preferably, the temperature of the metered methanol entering the vaporizer is controlled at 80-120 ℃, so as to form gas-phase methanol with the pressure of 0.30-0.40 MPa; when urea aqueous solution is used as ammonia decomposition source, the gasification temperature of methanol is controlled to be 110-120 ℃ to form gas-phase methanol with pressure of 0.60-0.75 MPa.
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