CN117603058A - Method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by cyclohexanol ammonification method - Google Patents
Method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by cyclohexanol ammonification method Download PDFInfo
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- CN117603058A CN117603058A CN202311557305.8A CN202311557305A CN117603058A CN 117603058 A CN117603058 A CN 117603058A CN 202311557305 A CN202311557305 A CN 202311557305A CN 117603058 A CN117603058 A CN 117603058A
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- PAFZNILMFXTMIY-UHFFFAOYSA-N cyclohexylamine Chemical compound NC1CCCCC1 PAFZNILMFXTMIY-UHFFFAOYSA-N 0.000 title claims abstract description 232
- XBPCUCUWBYBCDP-UHFFFAOYSA-N Dicyclohexylamine Chemical compound C1CCCCC1NC1CCCCC1 XBPCUCUWBYBCDP-UHFFFAOYSA-N 0.000 title claims abstract description 73
- 238000000034 method Methods 0.000 title claims abstract description 31
- 150000001412 amines Chemical class 0.000 title claims abstract description 29
- 238000004176 ammonification Methods 0.000 title claims abstract description 15
- HPXRVTGHNJAIIH-UHFFFAOYSA-N cyclohexanol Chemical compound OC1CCCCC1 HPXRVTGHNJAIIH-UHFFFAOYSA-N 0.000 title claims description 25
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 65
- 230000018044 dehydration Effects 0.000 claims abstract description 47
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 47
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 45
- 238000011084 recovery Methods 0.000 claims abstract description 34
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 31
- 238000000746 purification Methods 0.000 claims abstract description 12
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 claims description 42
- 239000000463 material Substances 0.000 claims description 18
- 239000002351 wastewater Substances 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 14
- 238000009835 boiling Methods 0.000 claims description 10
- 230000015572 biosynthetic process Effects 0.000 claims description 9
- 238000003786 synthesis reaction Methods 0.000 claims description 9
- 239000002994 raw material Substances 0.000 claims description 6
- 239000002699 waste material Substances 0.000 claims description 2
- 239000000203 mixture Substances 0.000 abstract description 4
- 239000003795 chemical substances by application Substances 0.000 abstract description 3
- ZSIAUFGUXNUGDI-UHFFFAOYSA-N hexan-1-ol Chemical compound CCCCCCO ZSIAUFGUXNUGDI-UHFFFAOYSA-N 0.000 abstract 2
- 239000000047 product Substances 0.000 description 43
- 239000012535 impurity Substances 0.000 description 21
- -1 Cyclohexylamine Cyclohexanol Dicyclohexylamine Chemical compound 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 230000020335 dealkylation Effects 0.000 description 6
- 238000006900 dealkylation reaction Methods 0.000 description 6
- 238000001514 detection method Methods 0.000 description 4
- 239000012043 crude product Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 2
- 238000012824 chemical production Methods 0.000 description 2
- 239000012024 dehydrating agents Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000012074 organic phase Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 230000009615 deamination Effects 0.000 description 1
- 238000006481 deamination reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/86—Separation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/04—Preparation of compounds containing amino groups bound to a carbon skeleton by substitution of functional groups by amino groups
- C07C209/14—Preparation of compounds containing amino groups bound to a carbon skeleton by substitution of functional groups by amino groups by substitution of hydroxy groups or of etherified or esterified hydroxy groups
- C07C209/16—Preparation of compounds containing amino groups bound to a carbon skeleton by substitution of functional groups by amino groups by substitution of hydroxy groups or of etherified or esterified hydroxy groups with formation of amino groups bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2601/00—Systems containing only non-condensed rings
- C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
- C07C2601/14—The ring being saturated
Abstract
The invention belongs to the field of rectification and purification, and particularly discloses a method for obtaining cyclohexylamine and dicyclohexylamine through rectification and purification of crude amine obtained by a hexanol ammonification method, which comprises the following steps: condensing crude amine, then feeding the condensed crude amine into an ammonia tower for treatment, and feeding a product obtained from the bottom of the ammonia tower into a No. 1 cyclohexylamine dehydration tower for rectification treatment; feeding azeotrope I of the cyclohexylamine and water extracted from the top of the 1# cyclohexylamine dehydration tower into a pressurizing recovery tower for pressurizing rectification treatment, and feeding the tower bottom product of the 1# cyclohexylamine dehydration tower into the cyclohexylamine tower for rectifying and purifying the cyclohexylamine product; extracting cyclohexylamine as a product from the top of the cyclohexylamine tower, and allowing a tower bottom product of the cyclohexylamine tower to enter a dealcoholization tower for dealcoholization; and (3) feeding the product obtained from the tower bottom of the dealcoholization tower into a dicyclohexylamine tower to carry out rectification, recovery and purification treatment on dicyclohexylamine products. The invention can successfully separate water by the difference of water content in azeotropic composition of pressure rectification without water carrying agent, and obtain high-content cyclohexylamine and dicyclohexylamine.
Description
Technical Field
The invention belongs to the field of rectification and purification, and particularly relates to a rectification and purification process for preparing cyclohexylamine and dicyclohexylamine by a cyclohexanol ammonification method.
Background
Cyclohexylamine is also called hexahydroaniline, and is an important chemical organic intermediate. Cyclohexylamine is an organic compound, colorless liquid, has strong ammonia smell and has strong organic alkali property.
The cyclohexanol ammonification method produces cyclohexylamine and dicyclohexylamine, and a crude product (crude amine) is obtained, wherein the crude product (crude amine) comprises cyclohexylamine, dicyclohexylamine, water, impurities and unreacted cyclohexanol and liquid ammonia, the cyclohexylamine and the dicyclohexylamine are target products, and water is a main reaction byproduct.
Deamination of crude amine, dehydration, reduced pressure rectification and collection to obtain the corresponding purified cyclohexylamine and dicyclohexylamine. According to literature query, the azeotropic temperature of the cyclohexylamine and the water at normal pressure is 96.4 ℃, the cyclohexylamine and the water are mutually soluble, and although the azeotrope is extracted by common rectification, the partially qualified cyclohexylamine product can be obtained, but the cyclohexylamine yield is low, and the cyclohexylamine and the water cannot be thoroughly separated.
In chemical production and technology, 2010, 17 (3), 57-61 articles adopt cyclohexane as azeotropic dehydrating agent, the azeotropic temperature of cyclohexane and water is 69 ℃, and the water content in azeotropic composition is 8.4%. The high-purity cyclohexylamine product is obtained through three steps of rectification of dehydration, dealkylation and amine distillation. The technology obtains a qualified product through rectification and purification by adding cyclohexane, but the cost is increased by adding cyclohexane, and impurities carried by the cyclohexane are introduced.
In conclusion, the existing rectification process is few, the cost is increased by adding a cyclohexane azeotropic rectification method, and cyclohexane impurities are introduced; there is therefore a need for improvements in the prior art described above.
Disclosure of Invention
The invention aims to provide a method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by a cyclohexanol ammonification method.
In order to solve the technical problems, the invention provides a method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by a cyclohexanol ammonification method, which comprises the following steps of:
s1, condensing crude amine, and then entering an ammonia tower, wherein the pressure of the ammonia tower is set to be 1.28-1.32 MPa, the temperature of the tower top is 40-42 ℃, and the temperature of the tower bottom is 170-175 ℃;
ammonia in the crude amine is discharged from the top of the ammonia tower as a reaction raw material after being formed by gas; feeding the product obtained from the bottom of the ammonia tower into a No. 1 cyclohexylamine dehydration tower for rectification treatment;
description: in this step, excess ammonia in the reaction is removed by an ammonia column and can be returned to the synthesis system;
s2, setting the pressure of a 1# cyclohexylamine dehydration tower to be-0.06 to-0.095 Mpa (preferably-0.088 to-0.090 MPa), the tower top temperature to be 40-75 ℃ and the tower bottom temperature to be 90-110 ℃;
extracting an azeotrope I of the cyclohexane and water from the top of a No. 1 cyclohexane dehydration tower (the water content is about 67% -69%), wherein the azeotrope I of the cyclohexane and water enters a pressurizing recovery tower to carry out pressurizing rectification treatment, and a tower bottom product of the No. 1 cyclohexane dehydration tower enters a cyclohexane tower to carry out rectification purification treatment of a cyclohexane product;
s3, setting the pressure of the pressurizing recovery tower to be 0.2-0.8 MPa, controlling the temperature of the tower top to be 115-175 ℃ and controlling the temperature of the tower bottom to be 120-180 ℃;
recovering an azeotrope II (the water content is about 55% -60%) of the cyclohexane and the water from the top of the pressurized recovery tower, returning the azeotrope II of the cyclohexane and the water to the No. 1 cyclohexane dehydration tower for rectification again, and discharging the wastewater generated at the bottom of the pressurized recovery tower into a wastewater pool;
s4, setting the pressure of the cyclohexylamine tower to be controlled to be minus 0.085 to minus 0.095Mpa (preferably minus 0.088 to minus 0.090 MPa), wherein the temperature of the tower top is 70 to 75 ℃ and the temperature of the tower bottom is 120 to 135 ℃;
the top of the cyclohexylamine tower is used for extracting cyclohexylamine (namely, finished cyclohexylamine) as a product, and the product obtained from the tower bottom of the cyclohexylamine tower enters a dealcoholization tower for dealcoholization;
s5, setting the pressure of a dealcoholization tower to be controlled at-0.085 to-0.095 MPa (preferably-0.088 to-0.092 MPa), wherein the temperature of the tower top is 100-105 ℃, and the temperature of the tower bottom is 145-150 ℃;
the cyclohexanol extracted from the top of the dealcoholization tower is used as a raw material for recovery, and the product obtained from the bottom of the dealcoholization tower enters a dicyclohexylamine tower for rectification, recovery and purification of dicyclohexylamine products;
s6, setting the tower top pressure of the dicyclohexylamine tower: -0.085 to-0.095 MPa (preferably-0.088 to-0.092 MPa), the tower top temperature is 150-152 ℃, and the tower bottom temperature is 155-162 ℃;
dicyclohexylamine (i.e., dicyclohexylamine finished product) is extracted from the top of the dicyclohexylamine tower, and the product obtained from the bottom of the dicyclohexylamine tower (T-106) is high-boiling material, and the high-boiling material is discarded.
As an improvement of the method of the invention:
s1: the recovered ammonia is returned to the synthesis system in the reaction vessel;
s5: the recovered cyclohexanol is returned to the synthesis system within the reaction vessel.
As a further improvement of the process of the invention:
the wastewater generated at the tower bottom of the pressurized recovery tower is discharged into a wastewater pool;
the obtained material of the dicyclohexylamine tower bottom is high-boiling material, and the high-boiling material is used for waste treatment.
As a further improvement of the process according to the invention, preference is given to:
in S1, the ammonia column setting parameters are as follows: the pressure is 1.28-1.32 Mpa, the temperature of the tower top is 40-41 ℃, and the temperature of the tower bottom is 172-174 ℃;
in S2, the setting parameters of the No. 1 cyclohexylamine dehydration tower are as follows: the pressure is-0.088 to-0.090 MPa, the tower top temperature is 44-46 ℃, and the tower bottom temperature is 95-97 ℃;
s3, setting the following technological parameters of the pressurizing recovery tower: the pressure is 0.48-0.52 MPa, the temperature of the tower top is controlled to be 144-146 ℃, and the temperature of the tower bottom is controlled to be 148-152 ℃;
s4, controlling the pressure of the cyclohexylamine tower to be-0.088 to-0.090 MPa, the temperature of the tower top to be 71-72 ℃ and the temperature of the tower bottom to be 120-122 ℃;
s5, controlling the pressure of the dealcoholization tower to be-0.088 to-0.092 MPa, the tower top temperature to be 100-101 ℃ and the tower bottom temperature to be 148-150 ℃;
in S6, the overhead pressure of the dicyclohexylamine column: -0.088 to-0.092 MPa, the tower top temperature is 150-151 ℃, and the tower bottom temperature is 157-159 ℃.
In the invention, in the step S2, the tower pressure of the No. 1 cyclohexylamine dehydration tower (T-102) is-0.06 to-0.095 Mpa (preferably-0.088 to-0.090 Mpa), and in the step S3, the pressure of the pressurizing recovery tower (T-103) is 0.2 to 0.8Mpa (preferably 0.48 to 0.52 Mpa), and differential pressure is formed between the two towers. According to the invention, water can be successfully separated through the water content difference in the azeotropic composition of the pressure rectification without a water carrying agent, and the cyclohexylamine with the content of more than or equal to 99.9% and dicyclohexylamine with the content of more than or equal to 99.85% are obtained.
The invention separates and purifies the cyclohexylamine and the water by a differential pressure rectification purification process to obtain qualified cyclohexylamine and dicyclohexylamine products, and the separated water can meet the wastewater discharge requirement without other treatment, namely, wastewater generated in the tower kettle of the pressurized recovery tower (T-103) can be directly discharged into a wastewater pond.
In conclusion, the invention effectively treats crude amine obtained by producing cyclohexane and dicyclohexylamine by a cyclohexanol ammonification method, and adopts a method which does not depend on an external azeotropic agent to purify the cyclohexane and dicyclohexylamine by rectification. The invention successfully obtains the cyclohexylamine product with high yield and high purity by using a simple method.
Drawings
The following describes the embodiments of the present invention in further detail with reference to the accompanying drawings.
FIG. 1 is a schematic view of the apparatus of the present invention;
FIG. 2 is a schematic diagram of the apparatus used in comparative example 2.
Detailed Description
The invention will be further described with reference to the following specific examples, but the scope of the invention is not limited thereto:
example 1, a rectification and purification apparatus, as depicted in fig. 1:
comprises an ammonia tower T-101, a No. 1 cyclohexylamine dehydration tower T-102, a pressurizing and recycling tower T-103, a cyclohexylamine tower T-104, a dealcoholization tower T-105 and a dicyclohexylamine tower T-106;
the outlet of the tower kettle of the ammonia tower T-101 is connected with the feed inlet of a No. 1 cyclohexylamine dehydration tower T-102;
the top outlet of the No. 1 cyclohexylamine dehydration tower T-102 is connected with the feed inlet of the pressurizing recovery tower T-103, and the bottom outlet of the No. 1 cyclohexylamine dehydration tower T-102 is connected with the feed inlet of the cyclohexylamine tower T-104;
the top outlet of the pressurizing recovery tower T-103 is connected with the feed inlet of a No. 1 cyclohexylamine dehydration tower T-102; the tower kettle outlet of the pressurizing recovery tower T-103 is connected with a wastewater tank;
the outlet of the tower kettle of the cyclohexylamine tower T-104 is connected with the feed inlet of the dealcoholization tower T-105, and the outlet of the tower kettle of the dealcoholization tower T-105 is connected with the feed inlet of the dicyclohexylamine tower T-106.
The crude amine obtained by the cyclohexanol ammonification method used in the following cases is prepared by the method for producing cyclohexylamine and dicyclohexylamine by the cyclohexanol ammonification method: in the reaction vessel, cyclohexanol and liquid ammonia were reacted in a hydrogen-critical state, and the crude amine (crude product, the temperature of which was about 170 to 175 ℃ C.) was obtained, which contained the components shown in Table 1 below (mass%). Cyclohexylamine and dicyclohexylamine are target products, moisture (H) 2 O) is a main reaction byproduct, cyclohexanol and liquid ammonia are raw materials which do not participate in the reaction.
TABLE 1
| Name of the name | NH 3 | H 2 O | Cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| Crude amine | 5.56％ | 21.60％ | 56.45％ | 3.15％ | 12.98％ | Allowance of |
The method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by the cyclohexanol ammonification method in example 1 sequentially comprises the following steps:
s1, condensing crude amine to be less than or equal to 60 ℃ (meeting gas-liquid separation conditions) and then entering an ammonia tower T101, wherein the ammonia tower T101 is provided with the following parameters: the pressure is 1.30Mpa, the temperature of the tower top is 41.2 ℃, and the temperature of the tower bottom is 172.5 ℃; the ammonia in the crude amine is thus recovered as a gas stream which is withdrawn overhead from the ammonia column T101, and this recovered ammonia is subsequently returned to the synthesis system in the reaction vessel. The product obtained from the tower bottom of the ammonia tower T101 enters a 1# cyclohexylamine dehydration tower T-102 for rectification treatment;
in this step, excess ammonia in the reaction is removed by an ammonia column and returned to the synthesis system.
S2, setting parameters of the 1# cyclohexylamine dehydration tower T-102 are as follows: the pressure is-0.090 MPa, the tower top temperature is 45.5 ℃, and the tower bottom temperature is 95.5 ℃.
The azeotrope I (water content 68.9%) of the cyclohexylamine and water extracted from the top of the 1# cyclohexylamine dehydration tower T-102 enters the pressurized recovery tower T-103,1# cyclohexylamine dehydration tower T-102, and the tower bottom output of the cyclohexylamine tower T-104,1# cyclohexylamine dehydration tower T-102 comprises the following components:
| cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 76.86％ | 4.29％ | 17.67％ | 1.18％ |
S3, setting the following technological parameters of the pressurizing recovery tower T-103: the pressure is 0.50MPa, the temperature of the tower top is controlled to be 145.2 ℃, and the temperature of the tower bottom is controlled to be 150.8 ℃; and (3) cyclohexane and water azeotrope II (the water content is 55.7%) extracted from the top of the pressurizing and recycling tower T-103 are returned into the No. 1 cyclohexane dehydration tower T-102, and wastewater obtained from the bottom of the pressurizing and recycling tower T-103 is discharged into a wastewater pool.
The wastewater detection sample is as follows:
description: the discharge standard of the wastewater set by Q/JYB G1401.9-2022 is as follows:
thus, the wastewater produced in this step meets the discharge standard.
S4, setting the pressure of the cyclohexylamine tower T-104 at-0.090 MPa, the tower top temperature at 71.8 ℃ and the tower bottom temperature at 120.9 ℃.
And (3) extracting a cyclohexylamine product from the top of the cyclohexylamine tower T-104, wherein the purity of the cyclohexylamine product is more than or equal to 99.95%, and feeding the obtained product from the bottom of the cyclohexylamine tower T-104 into a dealcoholization tower T-105. The material components of the tower kettle of the cyclohexylamine tower T-104 are as follows:
| cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.17％ | 19.23％ | 79.25％ | 1.35％ |
S5, setting the pressure of the dealcoholization tower T-105 to be-0.090 MPa, controlling the tower top temperature to be 100.6 ℃ and controlling the tower bottom temperature to be 148.7 ℃.
Cyclohexanol extracted from the top of the dealcoholization tower T-105 is used as a raw material to be recovered, and the recovered cyclohexanol is subsequently returned to the reaction vessel. The product obtained from the tower kettle of the dealcoholization tower T-105 enters a dicyclohexylamine tower T-106;
the components of the product obtained from the tower kettle of the dealcoholization tower T-105:
| cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.01％ | 98.33％ | 1.66％ |
S6, setting the tower top pressure of the dicyclohexylamine tower T-106: -0.090MPa, tower top temperature 150.5 ℃ and tower bottom temperature 158.4 ℃.
The top of the dicyclohexylamine tower T-106 adopts a dicyclohexylamine finished product, the purity of the dicyclohexylamine product is more than or equal to 99.85 percent, and the high-boiling substances of the high-boiling materials discharged from the tower bottom of the dicyclohexylamine tower T-106 mainly comprise dicyclohexylamine and unknown impurities (the dicyclohexylamine accounts for about 30 percent).
In this example 1, the yield of cyclohexylamine was 99.54%, and the yield of dicyclohexylamine was 99.14%.
Cyclohexylamine yield = mass of cyclohexylamine product per unit time/mass of cyclohexylamine in crude amine per unit time; dicyclohexylamine yield = mass of dicyclohexylamine product per unit time per mass of dicyclohexylamine in crude amine per unit time.
Example 2: the following changes were made with respect to example 1:
s1, the step S1 of the embodiment 1 is the same;
s2, setting parameters of the 1# cyclohexylamine dehydration tower T-102 are changed into the following: the pressure is-0.070 MPa, the temperature of the tower top is 63.4 ℃, and the temperature of the tower bottom is 98.6 ℃.
The water content of the azeotrope of the cyclohexylamine and the water is 66.8 percent which is taken out from the top of the 1# cyclohexylamine dehydration tower T-102.
1# cyclohexylamine dehydration tower T-102 tower kettle component:
| cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 76.69％ | 4.25％ | 17.91％ | 1.15％ |
S3, changing the set technological parameters of the pressurizing recovery tower T-103 into the following steps: the pressure is 0.30MPa, and the temperature of the tower top is 126.8 ℃; the temperature of the tower kettle is 131.9 ℃;
the water content of the azeotrope of cyclohexylamine and water was 57.9% taken off at the top of the pressurized recovery column T-103.
And (3) a wastewater detection sample of the T-103 tower kettle of the pressurized recovery tower:
| COD concentration mg/L | Total nitrogen concentration mg/L | PH value |
| 1654 | 132 | 9.47 |
S4, setting parameters of the cyclohexylamine tower T-104 are changed into the following: the pressure is controlled at about-0.90 MPa, the temperature of the tower top is 71.7 ℃, and the temperature of the tower bottom is 121.1 ℃.
And the cyclohexylamine product is extracted from the top of the cyclohexylamine tower T-104, and the purity of the cyclohexylamine product is more than or equal to 99.95 percent. The material components of the tower kettle of the cyclohexylamine tower T-104 are as follows:
| cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.14％ | 19.29％ | 79.13％ | 1.44％ |
S5, the setting parameters of the dealcoholization tower T-105 are changed as follows: the pressure is controlled at-0.090 MPa, the temperature of the tower top is 100.4 ℃, and the temperature of the tower bottom is 149.8 ℃.
Dealcoholization tower T-105 tower kettle component:
| cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.01％ | 98.27％ | 1.72％ |
S6, setting parameters of the dicyclohexylamine tower T-106 are changed into the following: -0.090MPa, 150.3 ℃ overhead temperature and 157.5 ℃ tower bottom temperature.
The top of the dicyclohexylamine tower T-106 is provided with a dicyclohexylamine finished product, the purity of the dicyclohexylamine product is more than or equal to 99.85%, and the tower bottom of the dicyclohexylamine tower T-106 is provided with high-boiling materials, wherein the high-boiling materials mainly comprise dicyclohexylamine and unknown impurities (the dicyclohexylamine accounts for about 30%).
In this example 2, the yield of cyclohexylamine was 99.46%, and the yield of dicyclohexylamine was 99.19%.
Example 3: the following changes were made with respect to example 1:
s1 to S2 are the same as in steps S1 to S2 of example 1;
s3, changing the set technological parameters of the pressurizing recovery tower T-103 into the following steps: the pressure is 0.20MPa, and the temperature of the tower top is 115.5 ℃; the temperature of the tower kettle is 120.9 ℃;
the water content of the azeotrope of cyclohexylamine and water was 58.4% taken off at the top of the pressurized recovery column T-103.
And (3) a wastewater detection sample of the T-103 tower kettle of the pressurized recovery tower:
| COD concentration mg/L | Total nitrogen concentration mg/L | PH value |
| 1743 | 182 | 9.63 |
S4 to S6 are equivalent to steps S4 to S6 of example 1.
In this example 3, the yield of cyclohexylamine was 99.18% and the yield of dicyclohexylamine was 99.43%.
Example 4: the following changes were made with respect to example 2:
s1 to S2, steps S1 to S2 of example 2;
s3, changing the set technological parameters of the pressurizing recovery tower T-103 into the following steps: the pressure is 0.80MPa, and the temperature of the tower top is 165.5 ℃; the temperature of the tower kettle is 170.7 ℃;
the water content of the azeotrope of cyclohexylamine and water is 55.1% at the top of the pressurized recovery column T-103.
And (3) a wastewater detection sample of the T-103 tower kettle of the pressurized recovery tower:
| COD concentration mg/L | Total nitrogen concentration mg/L | PH value |
| 1638 | 166 | 9.29 |
S4 to S6 are the same as those of steps S4 to S6 of example 2.
In this example 4, the yield of cyclohexylamine was 99.37%, and the yield of dicyclohexylamine was 99.36%.
Comparative example 1, according to chemical production and technique 2010, 17 (3), 57 to 61, specifically as follows:
s1, the same as the step S1 of the embodiment 1. The product obtained from the bottom of the ammonia tower enters a cyclohexylamine dehydration tower for rectification treatment;
s2, adding cyclohexane as an azeotropic dehydrating agent, wherein the consumption of the cyclohexane is 15% of the mass of the crude amine;
the pressure of the cyclohexylamine dehydration tower is normal pressure, the temperature of the top of the tower is 76.9 ℃, and the temperature of the bottom of the tower is 138.9 ℃.
Cyclohexane and water azeotrope (water content is 8.4%) is extracted from the top of the cyclohexylamine dehydration tower, a water phase and an organic phase are formed after layering, the organic phase returns to the cyclohexylamine dehydration tower, and tower bottom products of the cyclohexylamine dehydration tower enter a dealkylation tower, and tower bottom components of the cyclohexylamine dehydration tower are as follows:
| cyclohexane | Cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 10.75％ | 68.47％ | 3.77％ | 16.03％ | 0.98％ |
S3, the dealkylation tower pressure is normal pressure, the tower top temperature is 86.5 ℃, and the tower bottom temperature is 140.2 ℃; cyclohexane is extracted from the top of the dealkylation tower and returned to the cyclohexylamine dehydration tower, and the output of the bottom of the dealkylation tower enters the cyclohexylamine tower. Dealkylation tower kettle components:
| cyclohexane | Cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.00％ | 76.72％ | 4.22％ | 17.96％ | 1.1％ |
S4, controlling the pressure of the cyclohexylamine tower to be about-0.088 MPa, and controlling the temperature of the tower top to be 71.5 ℃ and the temperature of the tower bottom to be 121.2 ℃. And (3) extracting a cyclohexylamine product from the top of the cyclohexylamine tower, wherein the purity of the cyclohexylamine product is more than or equal to 99.95%, and feeding the tower kettle product into a dealcoholization tower. The material components of the bottom of the cyclohexylamine tower are as follows:
| cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.14％ | 19.29％ | 79.13％ | 1.44％ |
S5, controlling the pressure of the dealcoholization tower at-0.089 MPa, the tower top temperature at 100.3 ℃ and the tower bottom temperature at 149.6 ℃.
Cyclohexanol extracted from the top of the dealcoholization tower is returned to the circulating tank and then returned to the synthesis system, and tower kettle materials enter the dicyclohexylamine tower. Dealcoholizing tower kettle components:
| cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.01％ | 98.21％ | 1.78％ |
The dehydration efficiency of the cyclohexane of example 1 of the present invention=68.9% -55.7% =13.2%, whereas the dehydration efficiency of the cyclohexane of this comparative example 1 is 8.4%. And comparative example 1 was azeotropically rectified with cyclohexane added, not only increasing the cost, but also introducing cyclohexane impurities.
Comparative example 2, elimination of the "differential pressure rectification" of the present invention, the apparatus used is shown in FIG. 2:
1) Step S1 of example 1. The product obtained from the tower bottom of the ammonia tower T-101 enters a 1# cyclohexylamine dehydration tower T-102 for rectification treatment;
2) The pressure of the No. 1 cyclohexylamine dehydration tower T-102 is-0.090 MPa, the tower top temperature is 45.4 ℃, and the tower bottom temperature is 96.4 ℃.
The azeotrope of the cyclohexane and water (the water content is 68-69%) is extracted from the top of the 1# cyclohexane dehydration tower T-102, and the tower bottom product of the 1# cyclohexane dehydration tower T-102 enters the tower bottom component of the cyclohexane tower T-104,1# cyclohexane dehydration tower T-102:
| cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 76.75％ | 4.26％ | 17.96％ | 1.03％ |
3) The pressure of the cyclohexylamine tower T-104 is controlled to be about-0.090 MPa, the tower top temperature is 71.5 ℃, and the tower bottom temperature is 120.8 ℃.
And (3) extracting a cyclohexylamine product from the top of the cyclohexylamine tower T-104, wherein the purity of the cyclohexylamine product is more than or equal to 99.95%, and feeding the product obtained from the tower bottom into a dealcoholization tower T-105. The material components of the tower kettle of the cyclohexylamine tower T-104 are as follows:
| cyclohexylamine | Cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.12％ | 19.31％ | 79.15％ | 1.42％ |
4) The pressure of the dealcoholization tower T-105 is controlled at-0.090 MPa, the tower top temperature is 100.5 ℃, and the tower bottom temperature is 149.9 ℃.
Cyclohexanol extracted from the top of the dealcoholization tower T-105 is returned to the circulating tank for recovery and then returned to the synthesis system, and tower kettle materials enter a dicyclohexylamine tower T-106. Dealcoholization tower T-105 tower kettle component:
| cyclohexanol | Dicyclohexylamine | Impurity(s) |
| 0.01％ | 98.24％ | 1.75％ |
5) Overhead pressure of dicyclohexylamine column T-106: -0.090MPa, 150.3 ℃ overhead temperature and 157.5 ℃ tower bottom temperature.
The dicyclohexylamine tower T-106 adopts a dicyclohexylamine finished product at the top, the purity of the dicyclohexylamine product is more than or equal to 99.7%, and the high-boiling-point material is discharged from the tower bottom of the dicyclohexylamine tower T-10), wherein the high-boiling-point material mainly comprises dicyclohexylamine and unknown impurities (the dicyclohexylamine accounts for about 30%).
In this comparative example 2, the cyclohexylamine yield was only 82%, which is far lower than that obtained in example 1 of the present invention.
The unrecovered cyclohexylamine product is present as a mixture of cyclohexylamine and water (water content about 68 to 69%).
Comparative example 3, relative to comparative example 2, was modified as follows:
the pressure of a No. 1 cyclohexylamine dehydration tower (T-102) is changed into 0.5MPa, the tower top temperature is controlled to 145.2 ℃ and the tower bottom temperature is controlled to 150.8 ℃ at 45.4 ℃ and the tower bottom temperature is changed into 0.4 ℃ respectively.
The result obtained was a cyclohexylamine yield of only 69%, which is far lower than that obtained in example 1 of the present invention.
Finally, it should also be noted that the above list is merely a few specific embodiments of the present invention. Obviously, the invention is not limited to the above embodiments, but many variations are possible. All modifications directly derived or suggested to one skilled in the art from the present disclosure should be considered as being within the scope of the present invention.
Claims (4)
1. The method for obtaining the cyclohexylamine and the dicyclohexylamine through rectifying and purifying the crude amine obtained by the cyclohexanol ammonification method is characterized by comprising the following steps of:
s1, condensing crude amine, then entering an ammonia tower (T101), setting the pressure of the ammonia tower (T101) to be 1.28-1.32 MPa, the tower top temperature to be 40-42 ℃ and the tower bottom temperature to be 170-175 ℃;
ammonia in the crude amine is discharged from the top of an ammonia tower (T101) as a reaction raw material after being formed as gas; the product obtained from the tower bottom of the ammonia tower (T101) enters a No. 1 cyclohexylamine dehydration tower (T-102) for rectification treatment;
s2, setting the pressure of a 1# cyclohexylamine dehydration tower (T-102) to be-0.060 to-0.095 Mpa, wherein the tower top temperature is 40-75 ℃, and the tower bottom temperature is 90-110 ℃;
extracting an azeotrope I of the cyclohexane and the water from the top of a No. 1 cyclohexane dehydration tower (T-102), wherein the azeotrope I of the cyclohexane and the water enters a pressurizing recovery tower (T-103) for pressurizing rectification treatment, and the obtained product at the tower bottom of the No. 1 cyclohexane dehydration tower enters a cyclohexane tower (T-104) for rectifying and purifying the cyclohexane product;
s3, setting the pressure of a pressurizing recovery tower (T-103) to be 0.2-0.8 MPa, controlling the temperature of the tower top to be 115-175 ℃ and controlling the temperature of the tower bottom to be 120-180 ℃;
extracting an azeotrope II of the cyclohexane and the water from the top of the pressurizing recovery tower (T-103), and returning the azeotrope II of the cyclohexane and the water to a No. 1 cyclohexane dehydration tower (T-102) for rectification treatment again;
s4, setting the pressure of a cyclohexylamine tower (T-104) to be between-0.085 and-0.095 MPa, and controlling the temperature of the tower top to be between 70 and 75 ℃ and the temperature of the tower bottom to be between 120 and 135 ℃;
the top of the cyclohexylamine tower (T-104) is used for extracting cyclohexylamine as a product, and the tower bottom product of the cyclohexylamine tower (T-104) enters a dealcoholization tower (T-105) for dealcoholization treatment;
s5, setting the pressure of a dealcoholization tower (T-105) to be controlled at minus 0.085 to minus 0.095MPa, and controlling the temperature of the tower top to be 100 to 105 ℃ and the temperature of the tower bottom to be 145 to 150 ℃;
the cyclohexanol extracted from the top of the dealcoholization tower (T-105) is used as a raw material for recovery, and the product obtained from the tower bottom of the dealcoholization tower (T-105) enters a dicyclohexylamine tower (T-106) for rectification, recovery and purification of dicyclohexylamine products;
s6, setting the tower top pressure of the dicyclohexylamine tower (T-106): -0.085 to-0.095 MPa, the tower top temperature is 150-152 ℃, and the tower bottom temperature is 155-162 ℃;
dicyclohexylamine is taken off as product from the top of the dicyclohexylamine column (T-106).
2. The method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by a cyclohexanol ammonification method according to claim 1, characterized in that:
s1: the recovered ammonia is returned to the synthesis system in the reaction vessel;
s5: the recovered cyclohexanol is returned to the synthesis system within the reaction vessel.
3. The method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by the cyclohexanol ammonification method according to claim 1 or 2, characterized in that:
the wastewater generated by the tower kettle of the pressurizing recovery tower (T-103) is discharged into a wastewater pool;
the obtained product of the dicyclohexylamine tower (T-106) tower kettle is high-boiling material, and the high-boiling material is subjected to waste treatment.
4. A process for obtaining cyclohexylamine and dicyclohexylamine by rectification and purification of crude amine obtained by the ammonification of cyclohexanol according to any one of claims 1 to 3, characterized in that, as preferred:
in S1, the ammonia column (T101) setting parameters are as follows: the pressure is 1.28-1.32 Mpa, the temperature of the tower top is 40-41 ℃, and the temperature of the tower bottom is 172-174 ℃;
in S2, the setting parameters of the No. 1 cyclohexylamine dehydration tower (T-102) are as follows: the pressure is-0.088 to-0.090 MPa, the temperature of the tower top is 44-46 ℃, and the temperature of the tower bottom is 95-97 ℃;
s3, setting the following technological parameters of the pressurizing recovery tower (T-103): the pressure is 0.48-0.52 MPa, the temperature of the tower top is controlled to be 144-146 ℃, and the temperature of the tower bottom is controlled to be 148-152 ℃;
in S4, the pressure of the cyclohexylamine tower (T-104) is controlled to be-0.088 to-0.090 MPa, the temperature of the tower top is 71 to 72 ℃, and the temperature of the tower bottom is 120 to 122 ℃;
in S5, the pressure of a dealcoholization tower (T-105) is controlled to be-0.088 to-0.092 MPa, the temperature of the tower top is 100-101 ℃, and the temperature of the tower bottom is 148-150 ℃;
in S6, the overhead pressure of dicyclohexylamine column (T-106): -0.088 to-0.092 MPa, the tower top temperature is 150-151 ℃, and the tower bottom temperature is 157-159 ℃.
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| CN202311557305.8A CN117603058A (en) | 2023-11-21 | 2023-11-21 | Method for obtaining cyclohexylamine and dicyclohexylamine by rectifying and purifying crude amine obtained by cyclohexanol ammonification method |
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