CN116621674A - Purification method of crude chlorobutane - Google Patents
Purification method of crude chlorobutane Download PDFInfo
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- CN116621674A CN116621674A CN202310517867.3A CN202310517867A CN116621674A CN 116621674 A CN116621674 A CN 116621674A CN 202310517867 A CN202310517867 A CN 202310517867A CN 116621674 A CN116621674 A CN 116621674A
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- chlorobutane
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- butene
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- VFWCMGCRMGJXDK-UHFFFAOYSA-N 1-chlorobutane Chemical compound CCCCCl VFWCMGCRMGJXDK-UHFFFAOYSA-N 0.000 title claims abstract description 94
- 238000000034 method Methods 0.000 title claims abstract description 57
- 238000000746 purification Methods 0.000 title abstract description 7
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 claims abstract description 106
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims abstract description 100
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 claims abstract description 65
- 239000000463 material Substances 0.000 claims abstract description 62
- 238000010992 reflux Methods 0.000 claims abstract description 34
- 238000010521 absorption reaction Methods 0.000 claims abstract description 29
- 239000002994 raw material Substances 0.000 claims abstract description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 25
- DURPTKYDGMDSBL-UHFFFAOYSA-N 1-butoxybutane Chemical compound CCCCOCCCC DURPTKYDGMDSBL-UHFFFAOYSA-N 0.000 claims description 22
- 238000003786 synthesis reaction Methods 0.000 claims description 17
- 230000015572 biosynthetic process Effects 0.000 claims description 12
- 239000006096 absorbing agent Substances 0.000 claims description 6
- 239000002250 absorbent Substances 0.000 claims description 5
- 230000002745 absorbent Effects 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 abstract description 2
- 238000007599 discharging Methods 0.000 abstract 1
- 239000000047 product Substances 0.000 description 35
- 238000004458 analytical method Methods 0.000 description 8
- 238000004821 distillation Methods 0.000 description 8
- 239000000203 mixture Substances 0.000 description 5
- 239000006227 byproduct Substances 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000003379 elimination reaction Methods 0.000 description 3
- DQYBDCGIPTYXML-UHFFFAOYSA-N ethoxyethane;hydrate Chemical compound O.CCOCC DQYBDCGIPTYXML-UHFFFAOYSA-N 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 238000011143 downstream manufacturing Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000007259 addition reaction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000010517 secondary reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
- C07C17/383—Separation; Purification; Stabilisation; Use of additives by distillation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the field of preparation of chlorobutane, and discloses a purification method of crude chlorobutane, which comprises the following steps: (1) Carrying out first rectification on the crude chlorobutane raw material in a first rectifying tower to obtain a first rectifying tower bottom material and a first rectifying tower top material; (2) Carrying out second rectification on the material at the bottom of the first rectification tower in a second rectification tower; feeding the material at the top of the first rectifying tower into a butene absorption tank for absorption; wherein the reflux quantity of the first rectifying tower accounts for 35-50% of the feed quantity of the first rectifying tower; the theoretical total tray number of the first rectifying tower is 13-16, and the theoretical tray number of the feed inlet is 9-13. The product prepared by the method basically contains no 1-butene, the butanol content can be reduced to 0.01%, and the method provided by the invention avoids directly discharging the organic gas at the top of the tower into the air, and can recycle the 1-butene and the 1-butanol, thereby reducing the product cost.
Description
Technical Field
The invention relates to the field of preparation of chlorobutane, in particular to a purification method of crude chlorobutane.
Background
1-chloro-n-butane is an important pharmaceutical chemical intermediate, is an indispensable raw material for preparing a format reagent in high-grade carbon, and has special chemical properties, and the synthesis requirement: the purity of the 1-chloro-n-butane is more than 99.5%, the dibutyl ether content is less than 0.05%, the n-butanol content is less than 0.03%, and the water content is required to be below 80 ppm; since 1-butene is susceptible to addition reactions, affecting the chemical stability of the product, and has adverse effects on downstream product applications, it is necessary to control the 1-butene content.
Most of butanol in the crude chlorobutane prepared by the 1-chlorobutane production technology needs to be removed by water washing, and the water content in the crude chlorobutane is increased by the process, so that a byproduct 1-butene is generated in the subsequent rectification process. This is because chlorobutane undergoes elimination reaction under weakly alkaline high temperature conditions to produce 1-butene.
CN91105072.8 describes a catalyst-free synthesis of chlorobutane wherein a rectifying column is disclosed to directly purify the crude chlorobutane after water washing, with about 10% of the chlorobutane undergoing an elimination reaction to produce 1-butene. However, the patent does not describe a butene treatment process and the process results in a product with relatively high levels of byproducts (butanol and butene).
Disclosure of Invention
The invention aims to solve the problem that the purity of a chlorobutane product needs to be further improved in the prior art, and provides a purification method of crude chlorobutane. The product prepared by the method is basically free of 1-butene, and the butanol content can be reduced to 0.01%.
In order to achieve the above object, the present invention provides a method for purifying crude chlorobutane, comprising the steps of:
(1) Carrying out first rectification on the crude chlorobutane raw material in a first rectifying tower to obtain a first rectifying tower bottom material and a first rectifying tower top material;
(2) Carrying out second rectification on the material at the bottom of the first rectification tower in a second rectification tower; feeding the material at the top of the first rectifying tower into a butene absorption tank for absorption;
wherein the reflux quantity of the first rectifying tower accounts for 35-50% of the feed quantity of the first rectifying tower; the theoretical total tray number of the first rectifying tower is 13-16, and the theoretical tray number of the feed inlet is 9-13.
Preferably, the reflux amount of the first rectifying tower accounts for 40-50% of the feed amount of the first rectifying tower by mass percent.
Preferably, the theoretical total tray number of the first rectifying tower is 14-15, and the theoretical tray number of the feed inlet is 10-12. More preferably, the theoretical plate number of the feed inlet of the first rectification column is 12.
Preferably, the temperature of the top of the second rectification column is 1-3 ℃ higher than the temperature of the top of the first rectification column.
Preferably, the absorbent used in the butene absorber in step (2) is butanol, and the method further comprises feeding the material containing butanol and butene in the butene absorber to a chlorobutane synthesis process.
Compared with the prior art, the technical scheme of the invention has at least the following advantages:
(1) The method provided by the invention comprises the steps of carrying out first rectification on a crude chlorobutane raw material, then carrying out second rectification on a first rectifying tower bottom material, sending the first rectifying tower top material into a butene absorption tank for absorption, and controlling the reflux amount of the first rectifying tower and the feeding inlet position of the first rectifying tower to ensure that 1-butene is basically not contained in the prepared product; butanol content can be reduced from 0.1% to 0.01%;
(2) The method provided by the invention avoids the pollution to the environment by directly exhausting the organic gas at the top of the tower into the air;
(3) The method provided by the invention can recycle the 1-butene and the 1-butanol, and improves the conversion rate, thereby reducing the product cost.
Drawings
Fig. 1 is a schematic flow chart of a method for purifying crude chlorobutane according to one embodiment of the present invention.
Description of the reference numerals
1-first rectifying tower 2-second rectifying tower
3-butene absorption tank 4-synthetic kettle
5-crude chlorobutane intermediate tank 6-product tank
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, "inner and outer" refer to inner and outer with respect to the outline of each component itself.
It is to be understood that the present invention is not particularly limited to the "first" and "second" described herein, but is merely intended to distinguish between different processes or devices and operations involved in different processes.
The invention provides a method for purifying crude chlorobutane, which comprises the following steps:
(1) Carrying out first rectification on the crude chlorobutane raw material in a first rectifying tower to obtain a first rectifying tower bottom material and a first rectifying tower top material;
(2) Carrying out second rectification on the material at the bottom of the first rectification tower in a second rectification tower; feeding the material at the top of the first rectifying tower into a butene absorption tank for absorption;
wherein the reflux quantity of the first rectifying tower accounts for 35-50% of the feed quantity of the first rectifying tower; the theoretical total tray number of the first rectifying tower is 13-16, and the theoretical tray number of the feed inlet is 9-13.
In the present invention, the reflux amount of the first rectifying column may be 35%, 40%, 45% and 50% by mass of the feed amount of the first rectifying column, and any range of any two compositions. According to a preferred embodiment of the invention, the reflux amount of the first rectifying tower accounts for 40-50% of the mass percent of the feed amount of the first rectifying tower. The use of this preferred embodiment is more advantageous for the separation of 1-butene.
Preferably, the reflux material of the first rectification column is refluxed to the supply unit of crude chlorobutane feedstock. In this preferred embodiment, the reflux material of the first rectification column is refluxed to the supply unit of the crude chlorobutane raw material, and then fed into the first rectification column for the first rectification. More preferably, the conditions of the first rectification and the reflux amount of the first rectification column are such that the butene content in the material fed to the first rectification column is from 13.5 to 15.5% by weight. The preferred implementation is more beneficial to the separation of 1-butene, so that the product obtained by the second rectifying tower meets the requirement of downstream process.
The present invention is not particularly limited in the position of the outlet for the reflux material in the first rectifying column, and is preferably located above the feed inlet.
According to the invention, the theoretical total number of trays of the first rectification column is 13, 14, 15 or 16, preferably 14 or 15, and the theoretical number of trays of the feed inlet is 9, 10, 11, 12 or 13, most preferably 12. In the present invention, the theoretical plate number is the theoretical plate number of the upward number with the bottom of the first rectification column as the starting position (0).
It is understood that the theoretical plate number of the feed inlet of the first rectification column is less than the theoretical total plate number.
The invention can effectively separate out the butene and the butanol by controlling the reflux quantity of the first rectifying tower, the total tray number of the first rectifying tower and the tray number of the feeding port, and meets the requirements (for example, a format reagent) of a downstream process.
The composition and source of the raw material for the crude chlorobutane are not particularly limited, and the crude chlorobutane can be prepared by any existing chlorobutane method. Preferably, the crude chlorobutane feedstock contains chlorobutane and at least one of butanol, water, butene and butyl ether; based on the total amount of the crude chlorobutane raw material, the chlorobutane content is 94-99.99 wt%, the butanol content is 0-0.15 wt%, the water content is 0-3%, the butene content is 0-2%, and the butyl ether content is 0-1%; preferably, the content of the chlorobutane is 97.9 to 99.99 weight percent, the content of butanol is 0 to 0.1 weight percent, the content of water is 0 to 2 percent, the content of butene is 0 to 0.02 percent, and the content of butyl ether is 0 to 0.8 percent based on the total amount of the crude chlorobutane raw material.
According to the method provided by the invention, preferably, the conditions of the first rectification include: the temperature of the tower bottom is 80-85 ℃, and the temperature of the tower top is 67-72 ℃; further preferably, the feeding amount of the first rectification is 1600-2000kg/h, and the reflux amount of the first rectification column is 700-900kg/h.
The pressure of the first distillation is not particularly limited, and may be any pressure conventionally used in the art, as long as the smooth progress of distillation can be satisfied. For example, the pressure may be normal pressure.
According to the process provided by the invention, preferably, the conditions of the first rectification are such that the butene content in the first rectification bottom material is not higher than 0.02% by weight, preferably not higher than 0.005% by weight.
In the present invention, in the first rectifying column, the chlorobutane is subjected to elimination reaction in the column to produce 1-butene gas due to the high Wen Ruojian property environment. The invention controls the conditions to ensure that the 1-butene generated in the first rectification process flows out from the gas phase or the reflux pipeline at the top of the tower; wherein most of the butene gas is led to a butene absorption tank from the top of the tower to be absorbed, and then can be sent to a synthesis kettle for secondary reaction recovery, and part of butanol in the crude chlorobutane is removed in the process; and the other part of the butene gas is refluxed to the crude chlorobutane supply unit through a reflux pipeline, and then repeatedly purified through the first rectifying tower. The butene, butanol and water in the crude chlorobutane are effectively removed after the first rectifying tower is used for purification, the butanol content of the product obtained by the second rectifying tower is as low as 0.01%, the butene content is basically 0, and the water value is as low as 50ppm.
According to the present invention, preferably, the top temperature of the second rectification is 1-3 ℃ higher than the top temperature of the first rectification. The use of this preferred embodiment is more advantageous for the removal of butyl ether.
According to the invention, the second rectification is used for further purification of the first rectification bottom material, preferably the conditions of the second rectification include: the temperature of the tower bottom is 80-85 ℃, and the temperature of the tower top is 68-75 ℃.
The pressure of the second distillation is not particularly limited, and may be any pressure conventionally used in the art, as long as the smooth progress of distillation can be satisfied. For example, the pressure may be normal pressure.
According to a preferred embodiment of the invention, the distance from the feed inlet of the second rectification column to the top of the second rectification column is more than 90%, preferably 100% (i.e. fed from the bottom of the column) of the height of the second rectification column. The use of this preferred embodiment is more advantageous for the removal of butyl ether.
According to the invention, the theoretical total number of trays of the second rectification column is preferably from 12 to 13.
Preferably, the feed inlet of the second rectification column is lower than the feed inlet of the first rectification column. The use of this preferred embodiment is more advantageous for the removal of butyl ether.
The invention has a wide selection range of the type of the absorbent used in the butene-absorbing tank in the step (2), so long as the absorbent can absorb butene. Preferably, the absorbent used in the butene absorber in step (2) is butanol. With this preferred embodiment, the butanol having absorbed butenes may be sent to a chlorobutane synthesis process wherein both butenes and n-butanol may be reacted with hydrochloric acid at elevated temperatures to form chlorobutane. The method provided by the invention can not only reduce the content of byproducts 1-butene, butanol and water in the product, but also recycle the 1-butene, thereby greatly reducing the product cost and improving the market competitiveness.
Preferably, the process further comprises passing the feed comprising butanol and butene in the butene absorber to a chlorobutane synthesis process.
The invention provides a method for purifying crude chlorobutane, which is shown in figure 1 and comprises the following steps:
(1) Subjecting a crude chlorobutane feed, preferably provided by a crude chlorobutane intermediate tank 5, to a first rectification in a first rectification column 1 to obtain a first rectification column bottom material and a first rectification column top material;
(2) Carrying out second rectification on the first rectification tower bottom material in a second rectification tower 2; feeding the material at the top of the first rectifying tower into a butene absorption tank 3 filled with butanol for absorption;
(3) The material containing butanol, butene and chlorobutane in the butene absorption tank 3 is sent to a chlorobutane synthesis reaction process (preferably a synthesis kettle 4);
wherein the reflux quantity of the first rectifying tower accounts for 40-50% of the feed quantity of the first rectifying tower; the theoretical total tray number of the first rectifying tower is 14-15, and the theoretical tray number of the feed inlet is 10-12;
the conditions of the first rectification include: the temperature of the tower bottom is 80-85 ℃, and the temperature of the tower top is 67-72 ℃;
the feeding amount of the first rectification is 1600-2000kg/h, and the reflux amount of the first rectification tower is 700-900kg/h;
the temperature of the top of the second rectification is 1-3 ℃ higher than that of the top of the first rectification. By adopting the method provided by the invention, the 1-butene generated in the first rectification process can only flow out from the gas phase or the reflux pipeline at the top of the tower by controlling the condition of the first rectification, the reflux quantity and the feeding quantity and the duty ratio of the first rectification, the theoretical total tray number of the first rectification tower and the theoretical tray number of the feeding port, most of the butene gas is introduced into the butene absorption tank from the top of the tower and absorbed, and the other part of the butene gas is repeatedly purified by the first rectification tower after flowing back to the crude chlorobutane intermediate tank through the reflux pipeline, so that the product does not contain 1-butene. The material absorbed by the butene absorption tank can be used as a raw material of a synthesis process, 1-butene is effectively utilized, the direct emission of polluted air by 1-butene is avoided, the butanol content of a product purified by the second rectifying tower can be reduced from 0.1% to 0.01%, the butene content is 0, and the water value is below 50ppm.
Preferably the second rectification yields a product which is taken out of the system from the top of the second rectification column 2, preferably into a product tank 6.
In the present invention, the percentage refers to the mass percentage unless otherwise specified.
The present invention will be described in detail by examples.
Example 1
The crude chlorobutane composition includes: the content of chlorobutane is 97.95%, the content of butanol is 0.1%, the content of water is 1.88%, the content of butene is 0.003%, and the content of butyl ether is 0.06%.
(1) As shown in fig. 1, the crude chlorobutane raw material provided by the crude chlorobutane intermediate tank 5 is subjected to first rectification in the first rectification tower 1 to obtain a first rectification tower bottom material and a first rectification tower top material, wherein the theoretical total tray number of the first rectification tower is 14, the theoretical tray number of a feed inlet is 12, the temperature of a tower bottom is 85 ℃, the temperature of the tower top is 67-72 ℃, the feed amount of the first rectification tower is 1600kg/h, the reflux material flows back to the crude chlorobutane intermediate tank 5, and the flow rate of the reflux material is 750kg/h; during the operation of the system, the butene content of the material entering the first rectifying tower was 13.7 wt%;
(2) Carrying out second rectification on the first rectification tower bottom material in a second rectification tower 2; the temperature of the tower bottom of the second rectifying tower is 85 ℃, the tower top distillation temperature is 68-74 ℃, the theoretical total column plate number of the second rectifying tower 2 is 12, the distance from the feeding inlet of the second rectifying tower to the tower top of the second rectifying tower is 100% of the height of the second rectifying tower, the product is obtained from the tower top of the second rectifying tower, and the product is sent to a product tank 6 from a system;
(3) And (3) sending the material at the top of the first rectifying tower to a butene absorption tank 3 filled with butanol for absorption, and sending the material containing butanol, butene and chlorobutane in the butene absorption tank 3 to a synthesis kettle 4 to serve as a raw material of a chlorobutane synthesis reaction process.
According to analysis, the content of chlorobutane in the obtained product is 99.77%, the content of butanol is 0.01%, the content of water is 0.003%, no butene is present, and the content of butyl ether is 0.01%.
Example 2
The crude chlorobutane composition includes: the content of chlorobutane is 97.91%, the content of butanol is 0.1%, the content of water is 1.9%, the content of butene is 0.003%, and the content of butyl ether is 0.08%.
(1) As shown in fig. 1, the crude chlorobutane raw material provided by the crude chlorobutane intermediate tank 5 is subjected to first rectification in the first rectification tower 1 to obtain a first rectification tower bottom material and a first rectification tower top material, wherein the theoretical total tray number of the first rectification tower is 14, the theoretical tray number of a feed inlet is 12, the temperature of a tower bottom is 85 ℃, the temperature of the tower top is 67-72 ℃, the feed amount of the first rectification tower is 1600kg/h, the reflux material flows back to the crude chlorobutane intermediate tank 5, and the flow rate of the reflux material is 700kg/h; during the operation of the system, the butene content of the material entering the first rectifying tower was 14.5 wt%;
(2) Carrying out second rectification on the first rectification tower bottom material in a second rectification tower 2; the temperature of the tower bottom of the second rectifying tower is 85 ℃, the tower top distillation temperature is 68-74 ℃, the theoretical total column plate number of the second rectifying tower 2 is 12, the distance from the feeding inlet of the second rectifying tower to the tower top of the second rectifying tower is 100% of the height of the second rectifying tower, the product is obtained from the tower top of the second rectifying tower, and the product is sent to a product tank 6 from a system;
(3) And (3) sending the material at the top of the first rectifying tower to a butene absorption tank 3 filled with butanol for absorption, and sending the material containing butanol, butene and chlorobutane in the butene absorption tank 3 to a synthesis kettle 4 to serve as a raw material of a chlorobutane synthesis reaction process.
According to analysis, the content of chlorobutane in the obtained product is 99.72%, the content of butanol is 0.01%, the content of water is 0.004%, no butene is contained, and the content of butyl ether is 0.01%.
Example 3
The crude chlorobutane composition includes: the content of chlorobutane was 98.16%, the content of butanol was 0.15%, the content of water was 1.61%, the content of butene was 0.003%, and the content of butyl ether was 0.07%.
(1) As shown in fig. 1, the crude chlorobutane raw material provided by the crude chlorobutane intermediate tank 5 is subjected to first rectification in the first rectification tower 1 to obtain a first rectification tower bottom material and a first rectification tower top material, wherein the theoretical total tray number of the first rectification tower is 14, the theoretical tray number of a feed inlet is 12, the temperature of a tower bottom is 85 ℃, the tower top temperature is 67-72 ℃, the feed amount of the first rectification tower is 1900kg/h, the reflux material flows back to the crude chlorobutane intermediate tank 5, and the flow rate of the reflux material is 900kg/h; during the operation of the system, the butene content of the material entering the first rectifying tower was 14.8 wt%;
(2) Carrying out second rectification on the first rectification tower bottom material in a second rectification tower 2; the temperature of the tower bottom of the second rectifying tower is 85 ℃, the tower top distillation temperature is 68-74 ℃, the theoretical total column plate number of the second rectifying tower 2 is 12, the distance from the feeding inlet of the second rectifying tower to the tower top of the second rectifying tower is 100% of the height of the second rectifying tower, the product is obtained from the tower top of the second rectifying tower, and the product is sent to a product tank 6 from a system;
(3) And (3) sending the material at the top of the first rectifying tower to a butene absorption tank 3 filled with butanol for absorption, and sending the material containing butanol, butene and chlorobutane in the butene absorption tank 3 to a synthesis kettle 4 to serve as a raw material of a chlorobutane synthesis reaction process.
According to analysis, the content of chlorobutane, butanol, water and butyl ether in the obtained product is 99.64%, 0.03%, 0.005% and 0.009%, respectively.
Example 4
The procedure of example 3 was followed, except that the theoretical plate number of the feed inlet was 8. According to analysis, the content of chlorobutane, butanol, water, butene and butyl ether in the obtained product is 99.58%, 0.028%, 0.004%, 0.006% and 0.011%, respectively.
Example 5
The procedure of example 3 was followed except that the total number of trays in the first rectification column was 16 and the theoretical number of trays at the inlet was 12. According to analysis, the content of chlorobutane, butanol, water and butyl ether in the obtained product is 99.71%, 0.03%, 0.002%, and 0.01%, respectively.
Comparative example 1
The crude chlorobutane purity was: the content of chlorobutane is 98.22%, the content of butanol is 0.1%, the content of water is 1.54%, the content of butene is 0.003%, and the content of butyl ether is 0.054%; the method is characterized in that a first rectifying tower is not arranged, the feeding amount of a second rectifying tower is 1600kg/h, the temperature of a tower kettle is 85 ℃, the tower top distillation temperature is 70-75 ℃, the theoretical total tray number of the second rectifying tower 2 is 12, and the distance from a feeding inlet of the second rectifying tower to the tower top of the second rectifying tower is 100% of the height of the second rectifying tower.
According to analysis, the obtained product contains 99.42% of chlorobutane, 0.04% of butanol, 0.08% of water, 0.06% of butene and 0.02% of butyl ether. The product index can not meet the requirements of format reagent manufacturers.
Comparative example 2
The procedure of example 3 was followed, except that the butene content in the crude chlorobutane was increased to 16% by weight (additional butene feed) in the feed to the first rectification column.
According to analysis, the content of chlorobutane, butanol, water, butene and butyl ether in the obtained product is 99.63%, 0.03%, 0.004%, 0.002% and 0.013%, respectively.
Comparative example 3
The procedure of example 3 was followed, except that the reflux amount of the first rectification column was reduced to 600kg/h.
According to analysis, the content of chlorobutane, butanol, water and butyl ether in the obtained product is 99.55%, 0.03%, 0.005% and 0.03%, respectively. The butyl ether content is increased, and the product requirement is not met.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. A process for purifying crude chlorobutane, comprising the steps of:
(1) Carrying out first rectification on the crude chlorobutane raw material in a first rectifying tower to obtain a first rectifying tower bottom material and a first rectifying tower top material;
(2) Carrying out second rectification on the material at the bottom of the first rectification tower in a second rectification tower; feeding the material at the top of the first rectifying tower into a butene absorption tank for absorption;
wherein the reflux quantity of the first rectifying tower accounts for 35-50% of the feed quantity of the first rectifying tower; the theoretical total tray number of the first rectifying tower is 13-16, and the theoretical tray number of the feed inlet is 9-13.
2. The method according to claim 1, wherein the reflux amount of the first rectifying tower accounts for 40-50% by mass of the feed amount of the first rectifying tower;
preferably, the reflux material of the first rectification column is refluxed to the supply unit of crude chlorobutane feedstock.
3. The process according to claim 1, wherein the theoretical total number of trays of the first rectification column is from 14 to 15, and the theoretical number of trays of the feed inlet is from 10 to 12, preferably 12.
4. The process of claim 1, wherein the crude chlorobutane feed comprises chlorobutane and at least one of butanol, water, butene, and butyl ether;
based on the total amount of the crude chlorobutane raw material, the chlorobutane content is 92-99.99 wt%, the butanol content is 0-2 wt%, the water content is 0-3%, the butene content is 0-2%, and the butyl ether content is 0-1%.
5. The method according to any one of claims 1 to 4, wherein,
the conditions of the first rectification include: the temperature of the tower bottom is 80-85 ℃, and the temperature of the tower top is 67-72 ℃;
preferably, the feeding amount of the first rectification is 1600-2000kg/h, and the reflux amount of the first rectification tower is 700-900kg/h.
6. The method according to any one of claims 1 to 5, wherein,
the conditions of the first rectification and the reflux quantity of the first rectification column are such that the butene content in the material entering the first rectification column is 13.5-15.5 wt%.
7. The method according to any one of claims 1-6, wherein,
the temperature of the top of the second rectification is 1-3 ℃ higher than that of the top of the first rectification;
preferably, the conditions of the second rectification include: the temperature of the tower bottom is 80-85 ℃, and the temperature of the tower top is 68-75 ℃.
8. The method according to any one of claims 1-7, wherein,
the distance from the feeding inlet of the second rectifying tower to the top of the second rectifying tower is more than 90% of the height of the second rectifying tower;
preferably, the feed inlet of the second rectification column is lower than the feed inlet of the first rectification column.
9. The process of any one of claims 1-8, wherein the absorbent used in the butene absorber of step (2) is butanol;
preferably, the process further comprises passing the feed comprising butanol and butene in the butene absorber to a chlorobutane synthesis process.
10. A process for purifying crude chlorobutane, comprising the steps of:
(1) Carrying out first rectification on the crude chlorobutane raw material in a first rectifying tower to obtain a first rectifying tower bottom material and a first rectifying tower top material;
(2) Carrying out second rectification on the material at the bottom of the first rectification tower in a second rectification tower; feeding the material at the top of the first rectifying tower into a butene absorption tank filled with butanol for absorption;
(3) The materials containing butanol, butene and chlorobutane in the butene absorption tank are sent to a chlorobutane synthesis reaction procedure;
wherein the reflux quantity of the first rectifying tower accounts for 40-50% of the feed quantity of the first rectifying tower; the theoretical total tray number of the first rectifying tower is 14-15, and the theoretical tray number of the feed inlet is 10-12;
the conditions of the first rectification include: the temperature of the tower bottom is 80-85 ℃, and the temperature of the tower top is 67-72 ℃;
the feeding amount of the first rectification is 1600-2000kg/h, and the reflux amount of the first rectification tower is 700-900kg/h;
the temperature of the top of the second rectification is 1-3 ℃ higher than that of the top of the first rectification.
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| CN202310517867.3A CN116621674B (en) | 2023-05-09 | Purification method of crude chlorobutane |
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| CN202310517867.3A CN116621674B (en) | 2023-05-09 | Purification method of crude chlorobutane |
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