CN116589382A

CN116589382A - Industrial IPDI synthesis method

Info

Publication number: CN116589382A
Application number: CN202211207615.2A
Authority: CN
Inventors: 李方彬; 孙学文; 易水晗
Original assignee: Sichuan Yuanli Material Technology Co ltd
Current assignee: Sichuan Yuanli Material Technology Co ltd
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2023-08-15

Abstract

The invention relates to the technical field of IPDI synthesis, in particular to an industrialized IPDI synthesis process, which comprises a synthesis process of isophorone dicarbamate n-butyl and a thermal cracking process of isophorone dicarbamate n-butyl. The synthesis process has the advantages of simple flow, little pollution, high raw material utilization rate and high economic benefit, and is suitable for large-scale industrial production.

Description

Industrial IPDI synthesis method

Technical Field

The invention relates to the technical field of IPDI synthesis, in particular to an industrial IPDI synthesis process.

Background

Isocyanate refers to a substance containing one or more NCO groups that reacts with polyols to synthesize polyurethane materials. The prior isocyanate mainly comprises MDI, TDI, HDI, IPDI, HMDI, XDI, NDI, PPDI, CHDI and other varieties. Of these, MDI and TDI are the two most predominant species at present, accounting for approximately over 90% of the total isocyanate, while HDI, IPDI and hydrogenated MDI have been increasingly used in recent years due to their excellent weatherability and yellowing resistance.

IPDI (isophorone diisocyanate, CAS No. 4098-71-9) is a preferred starting material for the synthesis of light-stable, weather-resistant polyamino acids, which are high-end products among the isocyanate starting materials. The polyurethane coating is mainly used in the fields of aqueous polyurethane dispersion liquid, anticorrosive paint, UV resin, adhesive, PU resin, printing ink and the like. Meanwhile, the IPDI can also be used in rocket propellant industry.

The production method of IPDI mainly comprises a phosgene method and a carbamate thermal cracking method, and the phosgene method is the main production method of diisocyanate at present. The phosgene method mainly comprises a liquid-phase phosgene method and a gas-phase phosgene method, but the liquid-phase phosgene method has long reaction time, large required solvent quantity, low space-time efficiency of a reactor, more byproducts and relatively lagging; a series of engineering technical problems such as safety, environmental protection and the like in the production process of the gas-phase phosgene method are difficult to solve, the equipment is severely corroded, the requirements on equipment materials are relatively high, the corresponding equipment investment is relatively high, and the obtained isocyanate product contains hydrolytic chlorine, so that the usability of the product is affected. Thus, developed countries have been devoted to develop economical and simple synthetic methods, and thus various methods for synthesizing isocyanates by non-phosgene methods, such as a carbonylation method, a chloroformyl amide thermal decomposition method, a critium rearrangement method, an amine and chloroformyl ester reaction method, a carbamate thermal decomposition method, etc., have been developed, but most of them remain in laboratory stages, and only the carbamate thermal decomposition method has achieved the production of devices abroad. The urea method has the most studied route, is mature and is industrially applied. The urea method isocyanate preparation process comprises two steps, namely, reacting urea, diamine and alcohol to generate the dicarbamate, and performing reheat pyrolysis on the dicarbamate to generate isocyanate and alcohol, wherein the total reaction yield can reach 90%.

The development and production of diisocyanate in China are relatively late, but with the rapid development of society and economy in China, china becomes a global country for producing and consuming diisocyanate. On the other hand, in the field of high-performance special isocyanate, the development of China is very slow, and the consumption demand is increased by more than 15% in year. The aliphatic isocyanate is mainly applied to the fields of automotive finishing paint, rocket propellant, anti-corrosion paint, photo-curing paint, adhesive and the like. Because of the history of the introduction technology, the high-grade paint for industries such as automobiles, high-speed trains, airplanes, ships, luxury buses, wood furniture, buildings and the like in China is fully occupied by foreign products, wherein one of restriction factors is the key raw material aliphatic diisocyanate.

At present, the annual demand of HDI and IPDI in China is about 9.5 ten thousand tons, and the HDI and IPDI are mainly occupied by a few nationwide companies such as winning, de-Gusai and the like. The domestic product demand basically depends on import, and part of high-end military varieties are limited and sold in China. Therefore, the aliphatic diisocyanate is produced in China, and particularly, the non-phosgene green synthesis technology is adopted, so that the method is very necessary for promoting the technical progress and the industrial upgrading of related industries and guaranteeing the industrial safety of important industries in China, and has great economic benefit and great social significance.

The aliphatic diisocyanate is produced in China, particularly by adopting a non-phosgene green synthesis technology, is very necessary for promoting the technical progress and industry upgrading of related industries and guaranteeing the industrial safety of important industries in China, has great economic benefit and great social significance, but only De-Gusai and Basv are respectively built with 1 ten thousand tons/year production devices by a non-phosgene method at present.

At present, the industrial urea method in China is still blank for producing the IPDI, and the industrial urea method is based on the important significance of the IPDI on national economy and industry safety. In view of the above, the invention provides an industrial process for synthesizing isophorone dicarbamate by adopting a urea method, which not only needs to radically eliminate the high environmental safety hidden danger in the process of a phosgene method, but also has the same competitiveness with the phosgene method technology in terms of cost.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an industrialized IPDI synthesis process which at least achieves the effects of simple process flow, small pollution, high raw material utilization rate, high economic benefit and suitability for large-scale industrialized production

The aim of the invention is realized by the following technical scheme:

the industrialized IPDI synthesis process is characterized in that: comprises a synthesis process of isophorone dicarbamate and a thermal cracking process of isophorone dicarbamate;

the synthesis process of isophorone dicarbamic acid n-butyl ester comprises the following steps: (1) Mixing IPDA (isophorone diamine, CAS No. 2855-13-2), n-butanol, urea and a catalyst I, and performing an alkoxycarbonyl reaction of the organic amine, wherein a carrier gas is introduced into the alkoxycarbonyl reaction to separate a byproduct ammonia component, and the reaction is performed to obtain isophorone dicarbamic acid n-butyl ester (IPDU-B) and a synthesis tail gas, wherein the synthesis tail gas contains the carrier gas, the n-butanol, the ammonium carbamate and the ammonia component;

(2) The synthetic tail gas is subjected to an n-butanol deamination process to obtain n-butanol and ammonia-containing tail gas;

the butanol deamination process comprises the following steps: and separating n-butanol and ammonia components in the synthesized tail gas by a rectification mode to obtain heavy-component n-butanol and light-component ammonia-containing tail gas.

(3) Removing the ammonia-containing tail gas through ammonium carbamate to obtain ammonium carbamate, n-butanol and ammonium carbamate-removed tail gas;

the method for removing the ammonium carbamate comprises the following steps: condensing the ammonia-containing tail gas to liquefy residual n-butanol in the ammonia-containing tail gas, reacting carbon dioxide with ammonia components to generate ammonium carbamate, and separating materials from ammonium carbamate powder and n-butanol liquid obtained by condensation;

the material separation is as follows: after the condensation treatment, firstly carrying out gas-liquid separation on the material obtained by condensation to obtain ammonia-containing tail gas containing ammonium carbamate powder and liquid-phase n-butanol, and then carrying out gas-solid separation on the ammonia-containing tail gas to remove solid ammonium carbamate.

(4) Removing residual n-butanol from the ammonium carbamate tail gas to obtain n-butanol and a butanol removal tail gas;

the method for removing the residual n-butanol comprises the following steps: cooling the ammonia carbamate tail gas to 15-25 ℃, and then adsorbing n-butanol in the tail gas by using an adsorbent;

the adsorbent comprises: molecular sieve, activated carbon and high-molecular adsorption resin.

(5) The butanol-removed tail gas is subjected to ammonia component removal treatment to obtain ammonium salt and final tail gas;

the ammonia component removal treatment comprises the following steps: and introducing the ammonia-containing tail gas into an acid solution to enable ammonia components in the ammonia-containing tail gas to react with the acid to generate ammonium salt.

The thermal cracking process of isophorone dicarbamate n-butyl ester comprises the following steps:

(6) Pyrolysis of isophorone dicarbamate: carrying out first thermal decomposition reaction on isophorone dicarbamate, a solvent and a catalyst II to obtain a gas-phase material I, carrying out rectification operation on the gas-phase material I to obtain a gas-phase material II and a liquid-phase material II, carrying out second thermal decomposition reaction on the liquid-phase material II to obtain a gas-phase material III, and returning the gas-phase material III to the rectification operation, wherein the gas-phase material II is an IPDI product;

(7) And heavy component material discharging: the first thermal decomposition reaction and the second thermal decomposition reaction also obtain heavy component materials, and the first thermal decomposition reaction and the second thermal decomposition reaction need to discharge the heavy component materials;

(8) The rectification operation steps are as follows:

s1, feeding a gas phase material I and a gas phase material III into a first rectifying tower for rectification, extracting n-butanol from the top of the first rectifying tower, extracting IPDI rich liquid from the side line of the middle part of the tower, and removing isophorone dicarbamic acid n-butyl ester from the material at the bottom of the tower for pyrolysis;

s2, the IPDI rich liquid enters a second rectifying tower to carry out rectification, n-butanol and IPDI are extracted from the top of the second rectifying tower, an IPDI product is extracted from the side line of the middle part of the tower, and the pyrolysis step of isophorone dicarbamic acid n-butyl ester is carried out on the material in the tower bottom.

Further, in the synthesis process of isophorone dicarbamate n-butyl ester, the molar ratio of urea, n-butanol, IPDA and the catalyst I is 1: 4-10: 2 to 2.5:0.001 to 0.012; the reaction temperature of the alkoxycarbonyl reaction is 200-250 ℃, and the reaction pressure is 0.9-2.3 MPa.

Preferably, the molar ratio of IPDA, n-butanol, urea and catalyst I is 1: 5-8: 2 to 2.3: 0.004-0.01; the reaction temperature is preferably 215-235 deg.c and the reaction pressure is 1.2-1.5 MPa.

Further, the catalyst I comprises: at least one of zinc acetate, manganese acetate, zirconium acetate and cobalt acetate; preferably, the catalyst is zirconium acetate.

Further, the carrier gas is nitrogen.

Further, in the step (6) of the thermal cracking process of the phorone n-butyl dicarbamate, the pressure controlled by the first thermal decomposition reaction is-0.08 to-0.098 MPa, and the temperature is 200 to 280 ℃;

and/or, in the step 1), the pressure controlled by the second thermal decomposition reaction is-0.08 to-0.098 MPa, and the temperature is 200-280 ℃.

Further, in the step (6) of the thermal cracking process of the isophorone-n-butyl dicarbamate, the mass ratio of the isophorone-n-butyl dicarbamate, the solvent and the catalyst II is as follows: 1:0-9:0.0025-0.015.

Further, in the step (6) of the thermal cracking process of the n-butyl phorbol dicarbamate, the solvent is one of naphthenic oil, trioctyl trimellitate and trionyl trimellitate;

and/or the catalyst II is one or more of zinc picolinate, chromium picolinate, MOF-5, zinc oxide, bismuth trioxide, ionic liquid zinc, zinc chloride, zinc acetate, zinc acrylate and zinc isooctanoate.

Further, in the step (6) of the thermal cracking process of the n-butyl isophorone dicarbamate, when the solvent is naphthenic oil, the discharged heavy component material is heated and evaporated to obtain a gas-phase product and residues, and the gas-phase product can be used as the solvent in the pyrolysis step of the n-butyl isophorone dicarbamate after being condensed.

Further, in the step (6), the reactor of the first thermal decomposition reaction and/or the second thermal decomposition reaction is a thin film evaporator.

Further, in the step (8) of the thermal cracking process of the n-butyl phorate, the operation pressure of the first rectifying tower is 10 to 30mbar, the temperature of a tower bottom is 190 to 210 ℃, the operation temperature of a tower top is 20 to 30 ℃, and the lateral line temperature is 150 to 170 ℃;

and/or the operating pressure of the second rectifying tower is 10-30mbar, the temperature of the tower bottom is 190-200 ℃, the operating temperature of the tower top is 30-0 ℃, and the lateral line temperature is 155-160 ℃.

The beneficial effects of the invention are as follows:

the synthesis process has the advantages of simple flow, little pollution, high raw material utilization rate and high economic benefit, and is suitable for large-scale industrial production.

Drawings

FIG. 1 is a flow chart of an industrial urea process synthesis process of IPDU-B;

FIG. 2 is a flow chart of the process for producing IPDI by thermal cracking of IPDI U-B.

Detailed Description

The technical solution of the present invention will be described in further detail with reference to the accompanying drawings, but the scope of the present invention is not limited to the following description.

1. Equipment, raw materials, process flow and detection method for synthesizing IPDU-B by laboratory and industrial urea method.

Equipment used in laboratory urea process:

and (3) a reaction kettle: 10L; outlet condenser: Φ50X100;

raw material preparation by a laboratory urea method:

urea: GB/T2440-2001 industrial superior, total nitrogen (N) (on a dry basis) is more than or equal to 46.5%;

n-butanol: GB/T6027-1998 superior products with the main content more than or equal to 99.5 percent;

IPDA: the main content is more than or equal to 99.5 percent;

catalyst (zirconium acetate): the purity was 99.0%.

The specific method for synthesizing isophorone dicarbamate by using the urea method in the laboratory comprises the following steps:

IPDA, urea, n-butanol and a catalyst are added into a 10L stainless steel reaction kettle, and the synthesis reaction is carried out for 2 hours under the condition of the pressure of 1.50Mpa.G at 225 ℃ to generate isophorone-n-butyl dicarbamate, and simultaneously ammonia gas is discharged. Ammonia escapes through the evaporation of the supplemental nitrogen and the n-butanol, the n-butanol is condensed to automatically flow back to the reaction kettle shape, and the tail gas is absorbed by dilute sulfuric acid. After the synthesis reaction is finished, the reaction kettle is naturally cooled, and then a vacuum pump and an electric heater are started to evaporate the residual n-butanol in the kettle.

Equipment used in the industrialized urea method:

and (3) a reaction kettle: phi 1400 x 4253,5.4m ³ And (3) a deamination tower: phi 500 x 5000, flash evaporator phi 700 x 1600, falling film evaporator phi 1000 x 2500;

gas-solid separator: v=0.61 m ³ Φ700×1300 (straight tube);

butanol adsorption tower: 1800mm diameter, 2000mm height, 3 stations, operating conditions: 30-150 ℃ (regeneration 150 ℃), micro positive pressure;

and (3) a condenser: a=20m ² ；

Gas-liquid separator: v=0.61 m ³ Φ700×1300 (straight tube).

Raw material preparation:

urea: GB/T2440-2001 industrial high-grade product with actual purity of 99.6%;

n-butanol: GB/T6027-1998 superior products with actual main content of 99.8%;

IPDA: purity 99.5%;

catalyst (zirconium acetate): the purity was 99.0%.

The specific method for synthesizing isophorone dicarbamic acid n-butyl ester by adopting the industrialized urea method comprises the following steps:

adding liquid raw material n-butanol, raw material IPDA, solid raw material urea and liquid catalyst zirconium acetate into a 300L stainless steel reaction kettle, sealing the reaction kettle after the addition, replacing air in the kettle with nitrogen, and then introducing 4.5Nm according to the nitrogen ³ The temperature is raised to 225 ℃ and the synthesis reaction is carried out for 2 hours under the condition of the pressure of 1.50 Mpa.G. After the reaction is finished, decompressing and flashing part of n-butyl alcohol, circularly dealcoholizing for 2 hours by a falling film evaporator under the conditions of 200 ℃ and vacuum degree of-0.090 MPa, and removing unreacted n-butyl alcohol and intermediate product n-butyl carbamate to obtain an intermediate product isophorone dicarbamate n-butyl ester.

Introducing high-temperature ammonia-containing tail gas discharged in synthesis into a condenser by taking process nitrogen as carrier gas, cooling to 59 ℃, liquefying n-butanol at the moment, solidifying ammonium carbamate, introducing the tail gas into a gas-liquid separator again to remove n-butanol, blowing the ammonia and the ammonium carbamate into the gas-solid separator, and filtering and adsorbing the ammonium carbamate by the gas-solid separator to obtain the ammonia-removed tail gas containing residual n-butanol.

Introducing the ammonia-containing tail gas containing residual n-butanol into a precooler for cooling, maintaining the outlet temperature at 20deg.C, pumping the cooled tail gas with a blower for pressurizing, introducing nano adsorbent (particle size (0.6-1.25 mm) > 95%, specific surface area 1400 square meter/g, pore volume 0.90ml/g, and pore diameter)) Is provided. Introducing the adsorbed tail gas into a sulfuric acid tank to obtain ammonium salt and final tail gas

The detection method is shown in Table 1:

TABLE 1

Sequence number	Analysis item	Detection method
			1	IPDU-B content	GC-FID
2	N-butanol content	GC-FID
			3	Ammonia content	GC-FID
4	Ammonium carbamate content	GC-FID (CO measurement) ₂ Peak (Peak)

2. Screening the synthesis temperature and time in the process of synthesizing isophorone dicarbamic acid n-butyl ester by using a urea method in a laboratory:

the synthesis temperature gradient of 200 ℃,215 ℃, 225 ℃, 235 ℃, 250 ℃ was set, and the method for synthesizing IPDU-B by referring to a laboratory urea method (IPDA: 1289g (7.57 mol), n-butanol: 4487g (60.6 mol), urea: 1000g (16.5 mol)) was divided into 5 groups according to the temperature gradient to synthesize isophorone dicarbamate, and each group was further examined for the content of isophorone dicarbamate (IPDU-B) at reaction times of 1.5, 2, 3, 4, 5 hours, respectively, and the yield was calculated, and the statistical yield was shown in Table 1.

TABLE 2

Experiment number

Reaction temperature (. Degree. C.)

1.5h

2h

3h

4h

5h

1

200

65.7％

69.8％

73.4％

77.1％

81.2％

2

215

78.4％

91.47％

93.6％

97.2％

97.7％

3

225

92.7％

96.9％

98.5％

98.7％

97.6％

4

235

92.3％

94.6％

97.7％

98.3％

98.4％

5

250

91.6％

96.3％

98.1％

97.5％

97.1％

As is clear from Table 2, the yield of IPDU-B increases with increasing reaction temperature, but the reaction time continues to increase after the reaction time exceeds 2 hours, and the synthesis rate of IPDU-B becomes slower and the synthesis cost increases exponentially, so that the reaction time is preferably selected to be about 2 hours in view of economic efficiency. When the reaction temperature is 200-250 ℃ and the synthesis time is 2 hours, the yield of the IPDU-B is above 60 percent. When the reaction temperature is 215-250 ℃, the yield of IPDU-B is over 90%, the increase of the temperature yield is not obvious, and the synthesis temperature is selected to be the optimal reaction temperature from 200-250 and 215-235 is the optimal reaction temperature from the consideration of economic benefit.

3. Screening of synthesis pressure in a process for synthesizing isophorone dicarbamate by a urea method in a laboratory:

synthetic pressure gradients of 0.9, 1.1, 1.2, 1.3, 1.35, 1.4, 1.5, 1.8 and 2.3MPa were set, and according to the method for synthesizing IPDU-B by the laboratory urea method (IPDA: 1289g (7.57 mol), n-butanol: 4487g (60.6 mol) and urea: 1000g (16.5 mol)), isophorone n-butyl dicarbamate was synthesized by dividing the pressure gradient into 9 groups of experiments, and the content of isophorone n-butyl dicarbamate (IPDU-B) was detected and the yield was calculated, and the statistical yield was found in Table 3.

TABLE 3 Table 3

Experiment number	Reaction pressure (MPa)	IPDU-B yield (%)
			1	0.9	91.2
2	1.1	94.4
			3	1.2	96.2
4	1.3	97.5
			5	1.35	98.5
6	1.4	98.1
			7	1.5	98.3
8	1.8	98.2
			9	2.3	98.3

As is clear from Table 3, when the reaction pressure is more than 0.9MPa, the yield of IPDU-B is higher than 90%, and the yield is gradually increased with the gradual increase of the reaction pressure, but when the increase is smaller and smaller, the reaction pressure of 0.9-2.3MPa is preferable and the reaction pressure of 1.2-1.5MPa is preferable from the viewpoint of economic efficiency.

4. The industrial urea method for verifying the effect of synthesizing the IPDU-B product comprises the following steps:

158.5kg (2.14 kmol) of liquid raw material n-butanol, 45.5kg (0.27 kmol) of raw material IPDA, 35.5kg (0.57 kmol) of solid raw material urea and 400g (1.22 mol) of liquid catalyst zirconium acetate are added into a 300L stainless steel reaction kettle, the reaction kettle is closed after the addition, the air in the kettle is replaced by nitrogen, and then 4.5Nm of nitrogen is introduced according to the nitrogen introducing amount ³ The temperature is raised to 225 ℃ and the synthesis reaction is carried out for 2 hours under the condition of the pressure of 1.50 Mpa.G. After the reaction is finished, decompressing and flashing part of n-butyl alcohol, circularly dealcoholizing for 2 hours by a falling film evaporator under the conditions of 200 ℃ and vacuum degree of-0.090 MPa, and removing unreacted n-butyl alcohol and intermediate product n-butyl carbamate to obtain intermediate product isophorone dicarbamate n-butyl ester (97.5 kg, product yield of 98.4%) and ammonia-containing tail gas.

5. The treatment effect of industrial urea method for synthesizing IPDU-B waste gas is as follows:

according to the method for synthesizing the IPDU-B by the industrialized urea method (IPDA: 45.5kg (0.27 kmol), n-butanol: 158.5kg (2.14 kmol), urea: 35.5kg (0.57 kmol) and zirconium acetate (1.22 mol)), taking process nitrogen as carrier gas, introducing high-temperature ammonia-containing tail gas into a condenser, cooling to 59 ℃, liquefying n-butanol, solidifying ammonium carbamate, introducing the tail gas which is a mixture of ammonia gas, liquid n-butanol and ammonium carbamate solid into a gas-liquid separator to remove n-butanol, blowing ammonia gas and ammonium carbamate into a gas-solid separator, and filtering and adsorbing the ammonium carbamate by the gas-solid separator to obtain the ammonia de-carbamic acid ammonium tail gas containing residual n-butanol.

And (3) introducing the ammonium carbamate tail gas containing the residual n-butanol into a precooler for cooling, keeping the outlet temperature at 20 ℃, pumping and pressurizing the cooled tail gas by a fan, and introducing the tail gas into an adsorption tower filled with a nano adsorbent to obtain the butanol-removed tail gas. The adsorbed butanol-removed tail gas is introduced into a sulfuric acid tank to obtain ammonium salt and final tail gas, and the contents of each component in the ammonia-containing tail gas, the ammonium carbamate-removed tail gas and the final tail gas are detected, and the results are shown in table 4:

TABLE 4 Table 4

	Ammonia (%)	N-butanol (%)	Ammonium carbamate (%)	Nitrogen (%)
					Tail gas containing ammonia	48.43	1.18	0.62	49.77
Tail gas of deaminated ammonium formate	48.74	1.20	0.05	50.01
					Butanol removing tail gas	48.96	0.001	0.05	50.989
Final tail gas	0.003	Not detected	Not detected	99.997

As shown in Table 4, the high temperature ammonia-containing tail gas discharged from the synthesis of isophorone diamino n-butyl ester contains 0.62% of ammonium carbamate, and after the process of removing ammonium carbamate, the content of ammonium carbamate in the tail gas is only 0.05%, and the ammonium carbamate removal rate reaches 92%, which indicates that the process of removing ammonium carbamate can effectively remove ammonium carbamate in the process of synthesizing isophorone diamino n-butyl ester by a urea method, and can prevent pipelines and valves of industrial equipment from being blocked by ammonium carbamate. The ammonia content in the butanol-removing tail gas is 48.96%, and the ammonia content in the final tail gas is only 0.003%, which indicates that the ammonia in the tail gas can be effectively removed by the deamination process. The n-butanol content in the Hanan tail gas is 1.1%, and no n-butanol is detected in the final tail gas, which indicates that the whole tail gas removal process can effectively remove n-butanol in the tail gas.

6. Laboratory and industrial IPDU-B thermal cracking, solvent recovery, rectification reactor, reaction flow, raw material and detection method

(1) Laboratory thermal cracking reactor

A cracker: evaporation area 0.1m ² ；

And (3) a circulating pump: gear pump 2.8L/h;

rectifying column: Φ50X100;

(2) Thermal cracking reaction flow in laboratory

The raw materials enter a thin film evaporator (cracker) to be heated and cracked (namely, first thermal cracking reaction), and the IPDU-B, naphthenic oil and a small amount of IPDI which are not decomposed at the lower part are returned to the upper inlet of the cracker through a circulating pump. The pyrolysis gas (gas phase material I) from the upper part of the cracker enters a rectifying column under the vacuum action, the heavy component (liquid phase material II) flows back into the cracker (namely the second thermal cracking reaction) from the lower part of the rectifying column, the pyrolysis gas (gas phase material III) from the upper part of the cracker enters the rectifying column under the vacuum action, and the light component (gas phase material II) enters a heat exchanger from the upper part of the rectifying column, and flows into a crude product tank after being condensed. The thermal cracking temperature is 240 ℃ below zero, the operating pressure is 0.094mpa below zero, the addition amount of IPDU-B is 500g, and 500g of naphthenic oil KN4010 is added. ( And (3) injection: the first thermal cracking reaction and the second thermal cracking reaction are carried out separately in the same equipment, and the cracker is operated discontinuously )

(3) Industrial thermal cracking reactor

IPDU-B feed pump: q=2m ³ H, h=14m; 1# cracker: a=30m ² The method comprises the steps of carrying out a first treatment on the surface of the 1# pyrolysis circulation pump: q=5m ³ H, h=14m; 1# high polymer drainage pump: q=2m ³ H, h=14m; 2# cracker: a=25m ² The method comprises the steps of carrying out a first treatment on the surface of the 2# pyrolysis circulation pump: q=5m ³ H, h=14m; 2# high polymer drainage pump: q=2m ³ /h，H＝14m。

(4) Industrial thermal cracking reaction flow

(5) Solvent recovery device

Scraper evaporator: the specification parameters please supplement the heat exchange area s=12m ²

(6) Method for recovering solvent

Heavy component materials generated by the pyrolysis reaction of isophorone dicarbamate are pumped to the top of a scraper evaporator, a liquid film is forcedly formed on the inner wall of the evaporator through a rotary scraper, the liquid film is heated through the inner wall of the evaporator, the vapor phase product and the heavy component are obtained through evaporation under the vacuum condition, and the vapor phase product is condensed by a condenser to obtain the recovered solvent. Reaction conditions for heating evaporation: the temperature is 280 ℃, and the reaction pressure is-0.096 to-0.098 MPa.

(7) Reaction equipment for rectification

Light component removal column (rectifying column): phi 1200X 24604, filler height 3888/3888/3888/3240mm

Product column (rectifying column): phi 900X 24348 and packing height 3096/3096/4128/4128mm

And (3) a condenser: light component removing tower top condenser phi 1200 x 2000, heat exchange area 80m ² The method comprises the steps of carrying out a first treatment on the surface of the Product tower top condenser phi 1000 multiplied by 2000, heat exchange area 90m ²

Reboiler: the reboiler phi at the bottom of the light component removal tower is 1100 multiplied by 2500, and the heat exchange area is 94.5m ² The method comprises the steps of carrying out a first treatment on the surface of the The reboiler at the bottom of the product tower is phi 1400 multiplied by 3000, and the heat exchange area is 190m ²

And (3) a circulating pump: light component removal tower bottom circulating pump Q=10.8m ³ H= 40m Zone2 EEx dII BT4, product bottom circulation pump q=18m ³ H＝40m Zone2 EEx dII BT4

Auxiliary system: the heat conduction oil system provides a required heat source, the circulating water system and the chilled water system provide refrigerants, the nitrogen system provides nitrogen for the start-stop system to replace, and the vacuum system provides vacuum conditions required by the device

And (3) a control system: the process operation control adopts a DCS system and is provided with a Safety Interlock (SIS) system

(8) Reaction scheme of rectification

The gas-phase IPDI crude product (gas-phase material I and/or gas-phase material III) enters the light component removal tower bottom (first rectifying tower) from the thermal decomposition unit, n-butanol is extracted from the tower top, IPDI rich liquid is extracted from the side line in the middle of the tower, and the material in the tower bottom is circularly thermally decomposed (second thermal decomposition reaction) by the thermal decomposition unit. The IPDI rich liquid extracted from the side line of the light component removal tower is pumped into a product tower (a second rectifying tower), a small amount of n-butanol and IPDI are extracted from the top of the product tower, the IPDI product is extracted from the side line, and the material in the tower bottom (liquid phase material II) is subjected to cyclic thermal decomposition (a second thermal decomposition reaction) by a thermal decomposition unit.

(9) Raw materials

N-butyl isophorone dicarbamate (IPDU-B) component: the internal control index is more than or equal to 99.0 percent (99.38 percent of IPDU-B, 0.46 percent of catalyst for synthesizing the IPDU-B and the other 0.16 percent);

thermal cracking reaction catalyst: zinc picolinate, chromium picolinate, MOF-5, zinc oxide, bismuth trioxide, ionic liquid zinc, zinc chloride, zinc acetate, zinc acrylate, zinc isooctanoate;

solvent: naphthenic oil KN4010, naphthenic oil KN4006, naphthenic oil KN4016, trioctyl trimellitate and trionyl trimellitate.

(10) Detection method

See table 5:

TABLE 5

7. Screening of thermal cracking reaction conditions of IPDU-B

(1) Screening of thermal cracking temperatures

Operating conditions: selecting a laboratory thermal cracking reactor and a reaction flow, and controlling the cracking temperature of the cracker to 240 ℃; the operating pressure is minus 0.094Mpa; 500g of IPDU-B, 500g of naphthenic oil and 3.5g of chromium picolinate were charged, and the thermal cracking temperature was selected as shown in Table 6 below:

TABLE 6

Experiment lot number	Cracking temperature (. Degree. C.)	IPDU-B conversion (%)	IPDI yield(％)	Gum ratio (%)
					Group 3-1	240	99.65	92.34	2.12
Group 3-2	200	3.24	2.87	0.26
					Group 3-3	210	6.37	5.74	0.51
Groups 3-4	220	41.12	10.23	0.62
					Groups 3 to 5	230	97.2	84.67	1.03
Groups 3 to 6	260	99.82	91.13	3.87
					Groups 3 to 7	280	99.84	87.32	8.64

Note that: the main components of the colloid in the invention are catalyst and high molecular polymer (by-product); the gum ratio refers to the ratio of the gum production to the feed of the raw material IPDU-B.

As can be seen from Table 4, IPDI was produced by the reaction at a temperature in the range of 200 to 280 ℃; in the temperature range 220-280 ℃, the conversion of ipdi-B increases with increasing temperature, but as the temperature approaches 280 ℃, the gum production increases substantially, so the cleavage temperature is preferably 220-260 ℃.

(2) Screening of vacuum degree of thermal cracking reaction

Operating conditions: selecting a laboratory thermal cracking reactor and a reaction flow, and controlling the cracking temperature of the cracker to 240 ℃; 500g of IPDU-B, 500g of naphthenic oil and 3.5g of chromium picolinate are put into the reactor, and the vacuum degree of the thermal cracking reaction is screened, and the screening result of the vacuum degree of the thermal cracking reaction is shown in the following Table 7:

TABLE 7

Experiment lot number	Vacuum degree (gauge pressure Mpa)	IPDI yield (%)	Gum ratio (%)
				Group 4-1	-0.094	91.67	2.63
Group 4-2	-0.098	88.64	3.25
				Group 4-3	-0.096	88.87	3.31
Groups 4-4	-0.092	81.37	4.21
				Groups 4-5	-0.090	74.65	4.91
Groups 4-6	-0.085	58.23	6.27
				Groups 4-7	-0.080	44.63	8.17

As is clear from Table 5, when the vacuum degree is within the range of-0.080 to-0.098, the IPDI yields are constant; when the vacuum degree is within the range of-0.092 to-0.098, the yield of IPDI is highest, and the content of colloid is low.

8. Verification of thermal cracking reaction effect of industrial IPDU-B

Operating conditions: selecting an industrial thermal cracking reactor and a reaction flow, and controlling the IPDU-B through a circulation amount and a supplement amount: naphthenic oil KN4010: the mass ratio of the chromium picolinate is 1:1:0.007; 4 batches were performed on an industrial plant. The statistical results are shown in Table 8 below.

TABLE 8

As can be seen from Table 8, the yield of industrial IPDI was greater than 91%, which indicates that the feasibility of the industrial process and the industrial parameters determined by the invention was verified.

9. Recovery of solvent after reaction and reuse of recovered solvent

The influence of the recovery and reuse of the solvent on the industrial production is important, not only the production cost but also the pollutant discharge amount are determined, and therefore, the invention further examines the influence of the recovery and reuse of the solvent on the reaction. The recovered heavy component materials are obtained by combining an industrial thermal cracking reactor and a reaction flow, a solvent recovery device is used, naphthenic oil KN4010 is selected according to a solvent recovery method, the recovery results are shown in table 9, the recovered solvent is reused, the properties of thermal cracking products are measured, and the experimental results are shown in table 10.

TABLE 9

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Note that: the reaction conditions for group 3-1, group 3-2 and group 3-3 were: the temperature is 280 ℃, and the reaction pressure is-0.096 to-0.098 MPa. The temperature is 300 ℃, and the reaction pressure is-0.092 to-0.098 MPa. The temperature is 330 ℃, and the reaction pressure is minus 0.092 to minus 0.098MPa.

Table 10

Note that: the reaction conditions for group 4-1, group 4-2, group 4-3 and group 4-4 were all: the first thermal decomposition operating pressure is-0.094 Mpa, and the operating temperature is 240 ℃; the second thermal decomposition operating pressure is-0.094 Mpa and the operating temperature is 245 ℃.

As can be seen from tables 4, 5 and 6, the solvent provided by the present invention can be almost completely recovered and reused, and the use of the recovered solvent has no influence on the reaction.

10. Method for purifying crude IPDI (rectification operation)

(1) The specific components of the gas phase IPDI crude product are 19.54% of n-butanol, 28.64% of IPDI, 39.52% of unilateral side and 12.3% of naphthenic oil (solvent).

The operating conditions for controlling the light ends removal column are: 11mbar at the top of the tower, 24mbar at the bottom of the tower, 199.7 ℃ at the bottom of the tower, 25 ℃ at the top of the tower and 160.8 ℃ at the side line temperature; the operating conditions of the product column were: 11mbar at the top of the column, 24mbar at the bottom of the column, 194℃at the top of the column, 40℃at the top of the column and 158.3℃at the side line.

Taking n-butanol extracted from the top of a light component removal tower, IPDI rich liquid extracted from the side line of the middle part of the tower, and tower kettle materials; and taking n-butanol and IPDI which are extracted from the top of the product tower, and IPDI products and tower kettle materials which are extracted from the side line of the middle part of the tower. The ingredients and contents were measured separately, and the results are shown in Table 11 below:

TABLE 11

(2) The specific components of the gas phase IPDI crude product are 22.94% of n-butanol, 31.97% of IPDI, 34.63% of unilateral side and 10.46% of naphthenic oil.

The operating conditions for controlling the light ends removal column are: 11mbar at the top of the tower, 24mbar at the bottom of the tower, 200.4 ℃ at the temperature of the bottom of the tower, 25.5 ℃ at the operating temperature of the top of the tower and 161 ℃ at the side line temperature; the operating conditions of the product column were: 11mbar at the top of the column, 24mbar at the bottom of the column, 194.5℃at the top of the column, 40.5℃at the side stream and 158.5 ℃.

Taking n-butanol extracted from the top of a light component removal tower, IPDI rich liquid extracted from the side line of the middle part of the tower, and tower kettle materials; and taking n-butanol and IPDI which are extracted from the top of the product tower, and IPDI products and tower kettle materials which are extracted from the side line of the middle part of the tower. The ingredients and contents were measured separately, and the results are shown in Table 12 below:

table 12

(3) The specific components of the gas phase IPDI crude product are 20.05% of n-butanol, 38.21% of IPDI, 31.87% of unilateral side and 9.87% of naphthenic oil.

The operating conditions for controlling the light ends removal column are: 11mbar on the pressure tower top, 24mbar on the tower bottom, 201.5 ℃ on the tower bottom, 26 ℃ on the tower top operation temperature and 161.2 ℃ on the side line; the operating conditions of the product column were: the pressure at the top of the column was 11mbar, the temperature at the bottom of the column was 24mbar, the operating temperature at the top of the column was 194.9℃and the side stream temperature was 158.7 ℃.

Taking n-butanol extracted from the top of a light component removal tower, IPDI rich liquid extracted from the side line of the middle part of the tower, and tower kettle materials; and taking n-butanol and IPDI which are extracted from the top of the product tower, and IPDI products and tower kettle materials which are extracted from the side line of the middle part of the tower. The ingredients and contents were measured separately, and the results are shown in Table 13 below:

TABLE 13

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The foregoing is merely a preferred embodiment of the invention, and it is to be understood that the invention is not limited to the form disclosed herein but is not to be construed as excluding other embodiments, but is capable of numerous other combinations, modifications and environments and is capable of modifications within the scope of the inventive concept, either as taught or as a matter of routine skill or knowledge in the relevant art. And that modifications and variations which do not depart from the spirit and scope of the invention are intended to be within the scope of the appended claims.

Claims

1. The industrialized IPDI synthesis process is characterized in that: comprises a synthesis process of isophorone dicarbamate and a thermal cracking process of isophorone dicarbamate;

the synthesis process of isophorone dicarbamic acid n-butyl ester comprises the following steps:

(1) Taking IPDA, n-butanol, urea and a catalyst I to carry out an alkoxycarbonyl reaction of organic amine, introducing carrier gas in the process of the alkoxycarbonyl reaction to separate byproduct ammonia gas, and reacting to obtain isophorone dicarbamic acid n-butyl ester and synthetic tail gas containing ammonia components;

(8) The rectification operation steps are as follows:

2. The synthesis process according to claim 1, wherein:

in the synthesis process of isophorone dicarbamate n-butyl ester, the molar ratio of urea, n-butanol, IPDA and the catalyst I is 1: 4-10: 2 to 2.5:0.001 to 0.012; the reaction temperature of the alkoxycarbonyl reaction is 200-250 ℃, and the reaction pressure is 0.9-2.3 MPa.

3. The synthesis process according to claim 1, wherein: the catalyst I comprises: at least one of zinc acetate, manganese acetate, zirconium acetate and cobalt acetate.

4. The synthesis process according to claim 1, wherein: the carrier gas is nitrogen.

5. The synthesis process according to claim 1, wherein:

in the step (6) of the thermal cracking process of the n-butyl phorate, the pressure controlled by the first thermal decomposition reaction is-0.08 to-0.098 MPa, and the temperature is 200-280 ℃;

and/or, in the step 1), the pressure controlled by the second thermal decomposition reaction is 0.08-0.098 MPa, and the temperature is 200-280 ℃.

6. The synthesis process according to claim 1, wherein:

in the step (6) of the thermal cracking process of the isophorone dicarbamate, the mass ratio of the isophorone dicarbamate to the solvent to the catalyst II is: 1:0-9:0.0025-0.015.

7. The synthesis process according to claim 1, wherein: in the step (6) of the thermal cracking process of the n-butyl phorate, the solvent is one of naphthenic oil, trioctyl trimellitate and trionyl trimellitate;

8. The synthetic process of claim 7, wherein:

in the step (6) of the thermal cracking process of the n-butyl isophorone dicarbamate, the discharged heavy component material is heated and evaporated to obtain a gas-phase product and residues, and the gas-phase product can be used as a solvent in the pyrolysis step of the n-butyl isophorone dicarbamate after being condensed.

9. The synthetic process of claim 1 wherein in step (6), the reactor of the first thermal decomposition reaction and/or the second thermal decomposition reaction is a thin film evaporator.

10. The synthesis process according to claim 1, wherein:

in the step (8) of the thermal cracking process of the n-butyl phorate, the operating pressure of the first rectifying tower is 10-30mbar, the temperature of a tower kettle is 190-210 ℃, the operating temperature of the tower top is 20-30 ℃, and the lateral line temperature is 150-170 ℃;