CN116444338A - Method for preparing monofluoromethane based on methanol - Google Patents
Method for preparing monofluoromethane based on methanol Download PDFInfo
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- CN116444338A CN116444338A CN202310112330.9A CN202310112330A CN116444338A CN 116444338 A CN116444338 A CN 116444338A CN 202310112330 A CN202310112330 A CN 202310112330A CN 116444338 A CN116444338 A CN 116444338A
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 title claims abstract description 173
- NBVXSUQYWXRMNV-UHFFFAOYSA-N monofluoromethane Natural products FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 title claims abstract description 96
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000006243 chemical reaction Methods 0.000 claims abstract description 82
- 239000007788 liquid Substances 0.000 claims abstract description 45
- 238000000926 separation method Methods 0.000 claims abstract description 38
- 239000003054 catalyst Substances 0.000 claims abstract description 32
- 239000012043 crude product Substances 0.000 claims abstract description 12
- 239000000047 product Substances 0.000 claims abstract description 12
- 239000006200 vaporizer Substances 0.000 claims abstract description 10
- 230000008016 vaporization Effects 0.000 claims abstract description 7
- 208000005156 Dehydration Diseases 0.000 claims abstract description 6
- 230000018044 dehydration Effects 0.000 claims abstract description 6
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 5
- 238000004064 recycling Methods 0.000 claims abstract description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 27
- 239000007789 gas Substances 0.000 claims description 27
- 229910000040 hydrogen fluoride Inorganic materials 0.000 claims description 27
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 24
- BHHYHSUAOQUXJK-UHFFFAOYSA-L zinc fluoride Chemical compound F[Zn]F BHHYHSUAOQUXJK-UHFFFAOYSA-L 0.000 claims description 14
- 230000008569 process Effects 0.000 claims description 13
- 239000002808 molecular sieve Substances 0.000 claims description 10
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 10
- 230000003197 catalytic effect Effects 0.000 claims description 7
- 229910021563 chromium fluoride Inorganic materials 0.000 claims description 7
- FTBATIJJKIIOTP-UHFFFAOYSA-K trifluorochromium Chemical compound F[Cr](F)F FTBATIJJKIIOTP-UHFFFAOYSA-K 0.000 claims description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- 229910017052 cobalt Inorganic materials 0.000 claims description 3
- 239000010941 cobalt Substances 0.000 claims description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- YUOWTJMRMWQJDA-UHFFFAOYSA-J tin(iv) fluoride Chemical class [F-].[F-].[F-].[F-].[Sn+4] YUOWTJMRMWQJDA-UHFFFAOYSA-J 0.000 claims description 3
- 238000009834 vaporization Methods 0.000 claims description 3
- 238000004891 communication Methods 0.000 claims description 2
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims 1
- 238000002360 preparation method Methods 0.000 abstract description 16
- 239000002699 waste material Substances 0.000 abstract description 6
- 239000002994 raw material Substances 0.000 description 16
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 230000007547 defect Effects 0.000 description 6
- 239000002274 desiccant Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- 239000000376 reactant Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 229910021569 Manganese fluoride Inorganic materials 0.000 description 4
- CTNMMTCXUUFYAP-UHFFFAOYSA-L difluoromanganese Chemical group F[Mn]F CTNMMTCXUUFYAP-UHFFFAOYSA-L 0.000 description 4
- XWCDCDSDNJVCLO-UHFFFAOYSA-N Chlorofluoromethane Chemical compound FCCl XWCDCDSDNJVCLO-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 239000012752 auxiliary agent Substances 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- UMNKXPULIDJLSU-UHFFFAOYSA-N dichlorofluoromethane Chemical compound FC(Cl)Cl UMNKXPULIDJLSU-UHFFFAOYSA-N 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000003682 fluorination reaction Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 229910001515 alkali metal fluoride Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- LHMHCLYDBQOYTO-UHFFFAOYSA-N bromofluoromethane Chemical compound FCBr LHMHCLYDBQOYTO-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 208000012839 conversion disease Diseases 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000006298 dechlorination reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- VAYGXNSJCAHWJZ-UHFFFAOYSA-N dimethyl sulfate Chemical compound COS(=O)(=O)OC VAYGXNSJCAHWJZ-UHFFFAOYSA-N 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- BFNXPMYZRJXOIV-UHFFFAOYSA-N fluoridochlorine(1+) Chemical compound [Cl+]F BFNXPMYZRJXOIV-UHFFFAOYSA-N 0.000 description 1
- 238000005799 fluoromethylation reaction Methods 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 239000005457 ice water Substances 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229940050176 methyl chloride Drugs 0.000 description 1
- 125000004492 methyl ester group Chemical group 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
- C07C17/16—Preparation of halogenated hydrocarbons by replacement by halogens of hydroxyl groups
-
- 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
- C07C17/389—Separation; Purification; Stabilisation; Use of additives by adsorption on solids
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for preparing monofluoromethane based on methanol, which comprises the steps of dewatering methanol and/or a first-stage tower kettle component by a liquid dryer, vaporizing by a vaporizer, preheating by a preheater, and mixing by a mixer; introducing the mixed gas into a reaction tube filled with a catalyst for reaction to obtain a crude product; the crude product enters a gas-liquid separator for separation; introducing the separated gas into a gas dryer for dehydration treatment; introducing the dehydrated gas into a first-stage separation tower to separate to form a first-stage tower top component and a first-stage tower kettle component, and introducing the first-stage tower kettle component into a liquid dryer for recycling; the first-stage tower top component is introduced into a second-stage separation tower to be separated to form a second-stage tower top component and a second-stage tower bottom component, and the second-stage tower top component enters into a product collecting tank. The method for preparing the monofluoromethane based on the methanol has the advantages of low preparation cost, less three-waste generation and high conversion rate.
Description
Technical Field
The invention relates to a gas technology of the electronic industry, in particular to a method for preparing monofluoromethane based on methanol.
Background
Monofluoromethane of formula CH 3 F, also called HFC-41, is a nontoxic and liquefiable gas at normal temperature and pressure, can be used as a selective fluoromethylation reagent of organic molecules in organic synthesis and drug synthesis, and is also used as a raw material for producing an important pesticide intermediate fluorobromomethane. Due to its low green house effect potential (GWP 100 =116) and zero Ozone Depletion Potential (ODP), is one of the ideal working fluids for a low temperature heat pump; meanwhile, the high-purity monofluoromethane is widely applied to the semiconductor industry, is a green and efficient novel etching gas, and can be used for selectively etching a silicon compound film.
The current methods for preparing monofluoromethane mainly comprise the following steps:
(1) Gas phase hydrodechlorination process:
using monofluorodichloromethane (HCFC-21) or monofluorochloromethane (HCFC-31) as raw material, and making them react with H under the action of catalyst 2 Hydrogenation dechlorination reaction occurs.
CH 2 ClF+H 2 →CH 3 F+HCl
CHCl 2 F+H 2 →CH 3 F+2HCl
(2) Gas phase fluorination process:
methyl chloride is used as a raw material to react with HF in the presence of a catalyst.
CH 3 Cl+HF→CH 3 F+HCl
The two preparation methods have the problems of low conversion rate, more byproducts and the like, and the second product HCl and the monofluoromethane are easy to form an azeotrope. And the reaction materials HCFC-21 and HCFC-31 will consume substances and greenhouse Gases (GWP) with the ozone layer of the International society 100 >150 Production is prohibited and difficult to obtain.
(3) Methyl ester substitution process:
dimethyl sulfate or dimethyl carbonate is used as raw material to react with alkali metal fluoride to prepare HFC-41.
CH 3 OCOOCH 3 +2MF→CH 3 F+M 2 CO 3
CH 3 OSO 2 OCH 3 +2MF→CH 3 F+M 2 SO 4
The preparation method has the defects of low reaction conversion rate, incapability of realizing continuous production and large industrialization difficulty.
(4) Methanol fluorination process:
methanol is used as a raw material, and reacts with HF in the presence of a catalyst to prepare the monofluoromethane.
CH 3 OH+HF→CH 3 F+H 2 O
The preparation method has the defects of low conversion rate, large amount of water generated in the reaction process and great influence on the service life of the catalyst.
In summary, based on the defects existing in the current method for preparing monofluoromethane, when methanol is used as a raw material to prepare monofluoromethane, the defects of low conversion rate, large influence on the catalytic performance of the catalyst due to the large amount of water generated in the reaction, and the like need to be overcome.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.
Disclosure of Invention
The invention aims to provide a method for preparing monofluoromethane based on methanol, which has the advantages of low preparation cost, less three-waste generation, high conversion rate, simple process and easy realization.
To achieve the above object, an embodiment of the present invention provides a method for preparing monofluoromethane based on methanol, comprising the steps of:
(1) Dewatering the methanol and/or the first-stage tower kettle component through a liquid dryer;
(2) Vaporizing the dehydrated methanol and/or the first-stage tower kettle component by a vaporizer, and introducing the vaporized methanol and/or the first-stage tower kettle component into a mixer; meanwhile, anhydrous hydrogen fluoride is preheated by a preheater and is introduced into a mixer for mixing;
(3) Introducing hydrogen fluoride and methanol mixed in the step (2) according to the molar ratio of (0.9-1.1) to a reaction tube filled with a catalyst for reaction to obtain a crude product;
(4) The crude product enters a gas-liquid separator for separation;
(5) Introducing the gas separated in the step (4) into a gas dryer for dehydration treatment;
(6) Introducing the dehydrated gas into a first-stage separation tower to separate to form a first-stage tower top component and a first-stage tower kettle component, and introducing the first-stage tower kettle component into a liquid dryer for recycling;
(7) The first-stage tower top component is introduced into a second-stage separation tower to be separated to form a second-stage tower top component and a second-stage tower bottom component, and the second-stage tower top component enters a product collecting tank.
In one or more embodiments of the present invention, the vaporization temperature of the vaporizer in the step (2) is set to 70 to 100 ℃.
In one or more embodiments of the present invention, the preheating temperature of the preheater in the step (2) is set to 80 to 120 ℃.
In one or more embodiments of the present invention, the reaction temperature in the reaction tube in the step (3) is set to 200 to 500 ℃.
In one or more embodiments of the present invention, the liquid desiccant packed in the liquid dryer is a 3A molecular sieve, a 4A molecular sieve, a 5A molecular sieve, or a 13X molecular sieve, and the gas desiccant packed in the gas dryer is activated carbon in a spherical or rod shape.
In one or more embodiments of the present invention, the temperature of the top of the primary separation column in the step (6) is 0 to 10 ℃, the temperature of the bottom of the column is-20 to 0 ℃, the temperature of the top of the secondary separation column in the step (7) is-45 to-35 ℃, and the temperature of the bottom of the column is-100 to-80 ℃.
In one or more embodiments of the invention, the bottom of the first stage separation column in step (6) is in communication with the liquid inlet of the liquid dryer.
In one or more embodiments of the present invention, the catalyst in the step (3) is a supported catalyst, and a carrier of the supported catalyst is an activated carbon carrier, and the active components supported on the activated carbon carrier include the following components in mass ratio (0.5-5): 1 chromium fluoride and zinc fluoride.
In one or more embodiments of the invention, the supported catalyst is further supported with a catalytic promoter, the catalytic promoter in the active component comprising one or more of cobalt, nickel, copper, manganese or tin fluorides.
In one or more embodiments of the invention, the catalytic promoter in the active component comprises 0.1 to 5% of the total mass of the active component.
The invention takes methanol as raw material to react with hydrogen fluoride, the unreacted raw material in the reaction tube can be returned to the liquid dryer for continuous reaction, the generated crude product is purified by gas-liquid separation, drying, primary separation and secondary separation, high-purity monofluoromethane can be obtained, the conversion rate of the monofluoromethane is high, the three wastes are generated in the reaction process, the process is simple, and the raw material used in the reaction is easy to obtain, thus being easy to realize.
Drawings
Fig. 1 is a schematic diagram of a process for preparing monofluoromethane based on methanol in accordance with the present invention.
1-liquid dryer, 11-liquid desiccant, 12-methanol feed inlet; 2-vaporizer; 3-preheater, 31-HF feed inlet; 4-reactor, 41-mixer, 42-reaction tube, 43-catalyst; 5-gas-liquid separator, 51-filler and 52-water outlet; 6-gas dryer, 61-gas dryer, 62-liquid outlet; 7-first-stage separating tower, 71-first-stage tower bottom component discharge port and 72-first-stage tower top component discharge port; 8-a secondary separation tower, 81-a secondary tower kettle component discharge port and 82-a secondary tower top component discharge port; 9-product collection tank, 91-product filling outlet.
Detailed Description
The following detailed description of embodiments of the invention is, therefore, to be taken in conjunction with the accompanying drawings, and it is to be understood that the scope of the invention is not limited to the specific embodiments.
In order to solve the defects of low conversion rate, large three-waste generation amount and difficult treatment in the preparation method of the monofluoromethane in the prior art, particularly the defects that a large amount of water generated in the reaction has great influence on the catalytic performance of the catalyst and the like are overcome.
Specifically, referring to fig. 1, the method for preparing monofluoromethane based on methanol provided by the invention is implemented based on the device of fig. 1, and the method for preparing monofluoromethane based on methanol by using the device comprises the following steps:
(1) The introduced methanol and/or the primary tower kettle component are dehydrated by a liquid dryer;
(2) Vaporizing the dehydrated methanol and/or the first-stage tower kettle component by a vaporizer, and introducing the vaporized methanol and/or the first-stage tower kettle component into a mixer; meanwhile, anhydrous hydrogen fluoride is preheated by a preheater and is introduced into a mixer for mixing;
(3) Introducing hydrogen fluoride and methanol mixed in the step (2) according to the molar ratio of (0.9-1.1) to a reaction tube filled with a catalyst for reaction to obtain a crude product;
(4) The crude product enters a gas-liquid separator for separation;
(5) Introducing the gas separated in the step (4) into a gas dryer for dehydration treatment;
(6) Introducing the dehydrated gas into a first-stage separation tower to separate to form a first-stage tower top component and a first-stage tower kettle component, and introducing the first-stage tower kettle component into a liquid dryer for recycling;
(7) The first-stage tower top component is introduced into a second-stage separation tower to be separated to form a second-stage tower top component and a second-stage tower bottom component, and the second-stage tower top component enters into a product collecting tank.
In the embodiment of the invention, since the boiling point of methanol is 64.7 ℃, in order to vaporize the methanol in liquid state at normal temperature or the liquid part in the first-stage tower kettle component, the vaporization temperature of the vaporizer in the step (2) is set to be 70-100 ℃; thus, not only can the vaporized methanol be uniformly mixed with the hydrogen fluoride after entering the mixer, but also the reaction for preparing the monofluoromethane can be ensured to occur within a specified temperature range.
In the embodiment of the invention, hydrogen fluoride which is one of reactants needs to be preheated to reach the temperature range for preparing the monofluoromethane, and the preheating temperature of the preheater in the step (2) is set to be 80-120 ℃; thus, after the preheater preheats the hydrogen fluoride, the hydrogen fluoride is more beneficial to the uniform mixing of the gaseous methanol and the mixture in the mixer.
In the embodiment of the invention, in order to ensure that the reaction for preparing the monofluoromethane based on the methanol is carried out within a certain temperature range, the reaction temperature in the reaction tube in the step (3) is set to be 200-500 ℃, and the unreacted reactant in the reaction tube is added to be circularly introduced into the reaction tube at the reaction temperature, so that a higher conversion rate is obtained.
In the embodiment of the invention, the liquid desiccant filled in the liquid dryer is a 3A molecular sieve, a 4A molecular sieve, a 5A molecular sieve or a 13X molecular sieve, and the gas desiccant filled in the gas dryer is spherical or rod-shaped activated carbon. The liquid dryer and the gas dryer are respectively utilized to dry the liquid reactant and the gaseous reactant, so that when the reactant enters the reaction tube to react, the carried moisture has a larger influence on the catalytic effect of the catalyst, and the conversion rate of the reaction is reduced.
In the embodiment of the invention, the bottom of the first-stage separation tower in the step (6) is communicated with the liquid inlet of the liquid dryer. Therefore, after the reactant and the reaction product which do not react in the reaction tube are separated by the primary separation tower, the primary tower kettle component falls to the bottom of the primary separation tower and is introduced into the liquid dryer for cyclic reaction, so that the conversion rate is improved, and the generation of three wastes is reduced.
In the embodiment of the invention, the temperature of the top of the primary separation tower in the step (6) is 0-10 ℃, the temperature of the bottom of the tower is-20-0 ℃, the temperature of the top of the secondary separation tower in the step (7) is-45 to-35 ℃, and the temperature of the bottom of the tower is-100 to-80 ℃. The first-stage separation tower and the second-stage separation tower form gas-liquid two phases in the first-stage separation tower and the second-stage separation tower respectively through tower tops and tower bottoms with different temperatures, then gas-liquid separation is carried out, and finally the obtained gas-phase product is introduced into a product collecting tank for collection.
The catalyst used in any of the above embodiments is a supported catalyst, the carrier is an activated carbon carrier, and the activated carbon carrier is supported with a mass ratio of 50:1, the active component comprises chromium fluoride and zinc fluoride with the mass ratio of (0.5-5) to 1. Wherein the catalyst auxiliary agent in the active component is selected from one or more of cobalt, nickel, copper, manganese or tin fluoride, and the catalyst auxiliary agent accounts for 0.1-5% of the total mass of the active component.
Specifically, in the embodiment of the invention, the mass ratio of chromium fluoride to zinc fluoride in the active component of the supported catalyst is 1:1, and the catalyst auxiliary agent is manganese fluoride which accounts for 1% of the total mass of the active component.
The preparation method of the supported catalyst in the embodiment of the invention comprises the following steps:
the active carbon powder of 100-200 meshes is adopted, 20% nitric acid is firstly used for boiling and refluxing for 2 hours, then pure water is used for washing to be neutral, and then the active carbon carrier is obtained after drying at 120 ℃. The mass ratio is 1 by an impregnation method: 50 is loaded on an active carbon carrier, and the obtained active carbon carrier is mixed with nitric acid solution of chromium fluoride, zinc fluoride and manganese fluoride in an ice water mixed bath for 5 hours (the mass ratio of the chromium fluoride to the zinc fluoride to the manganese fluoride in the nitric acid solution is 99:99:2), filtered after pure water washing, dried for 12 hours at 80 ℃, then activated for 2 hours at 400 ℃, slowly cooled to room temperature, and the supported catalyst is prepared and is placed in a dry environment for standby.
The following description of the preferred embodiments of the present invention is made with reference to the accompanying drawings and detailed description, but it should be understood that the description is only for the purpose of further illustrating the features and advantages of the present invention and is not limiting the claims of the present invention. Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.
The catalyst 43 in the following examples was a supported catalyst in which the mass ratio of the activated carbon support and the active ingredient supported thereon was 50:1, the mass ratio of chromium fluoride, zinc fluoride and manganese fluoride in the active components is 99:99:2.
example 1
(1) Preparing hydrogen fluoride and methanol with a molar ratio of 1.1:1, wherein methanol and/or a first-stage tower kettle component is/are introduced into a liquid dryer 1 through a methanol feed inlet 12 for dehydration treatment, and a liquid desiccant 11 in the liquid dryer 1 is a 5A molecular sieve;
(2) The dehydrated methanol and/or the primary tower kettle component are vaporized by a vaporizer 2, the temperature of the vaporizer 2 is 80 ℃, and the vaporized methanol and/or primary tower kettle component is introduced into a mixer 41; meanwhile, anhydrous HF is preheated by the preheater 3 at a preheating temperature of 100 ℃, and is fed into the mixer 41 after being preheated, and uniformly mixed;
(3) Introducing the mixed gas into a reaction tube 42 filled with a catalyst 43 for reaction to obtain a crude product, wherein the reaction temperature in the reaction tube 42 is 320 ℃, and the contact time is 20s;
(4) The crude product enters the gas-liquid separator 5, most of water is separated by the filler 51, and the water is discharged through the water outlet 52;
(5) The gas after gas-liquid separation is introduced into a gas dryer 6 for dehydration, the gas dryer 61 is spherical or rod-shaped activated carbon, and the separated liquid is discharged through a liquid outlet 62;
(6) The dried gas is introduced into a first-stage separation tower 7, the temperature of the tower top is set to be 5-10 ℃, the temperature of the tower bottom is set to be-5-0 ℃, the obtained first-stage tower top components are gaseous fluoromethane and dimethyl ether, the gaseous fluoromethane and the dimethyl ether are discharged through a first-stage tower top component discharge port 72, the first-stage tower bottom components are methanol and HF in liquid phase, the methanol and HF are discharged through a first-stage tower bottom component discharge port 71, and a first-stage tower bottom group can be introduced into a liquid dryer 11 for continuous reaction;
(7) The first-stage tower top component is introduced into a second-stage separation tower 8, the temperature of the tower top is set to be-40 to-35 ℃, the temperature of the tower bottom is set to be-85 to-90 ℃, the obtained second-stage tower top component is gas-phase monofluoromethane, the gas-phase monofluoromethane is discharged through a second-stage tower top component discharge port 82, the product is collected into a product collecting tank 9 and can be output through a product filling outlet 91, the second-stage tower bottom component is liquid-phase dimethyl ether and a small amount of other impurities, the dimethyl ether is discharged through a second-stage tower bottom component discharge port 81, and the dimethyl ether can be used as industrial dimethyl ether after proper treatment.
Example 2
The preparation method of this example is substantially the same as that of example 1.
One of the differences is that: preparing hydrogen fluoride and methanol in a molar ratio of 1.05:1 in the step (1);
the second difference is that: the reaction temperature in the reaction tube in the step (3) is 350 ℃ and the contact time is 15s.
Example 3
The preparation method of this example is substantially the same as that of example 1.
One of the differences is that: preparing hydrogen fluoride and methanol in a molar ratio of 1:1 in the step (1);
the second difference is that: the reaction temperature in the reaction tube in the step (3) was 320℃and the contact time was 20s.
Example 4
The preparation method of this example is substantially the same as that of example 1.
One of the differences is that: preparing hydrogen fluoride and methanol in a molar ratio of 0.95:1 in the step (1);
the second difference is that: the reaction temperature in the reaction tube in the step (3) is 350 ℃ and the contact time is 15s.
Example 5
The preparation method of this example is substantially the same as that of example 1.
One of the differences is that: preparing hydrogen fluoride and methanol in a molar ratio of 0.9:1 in the step (1);
the second difference is that: the reaction temperature in the reaction tube in the step (3) was 320℃and the contact time was 15s.
Example 6
The preparation method of this example is substantially the same as that of example 1.
One of the differences is that: preparing hydrogen fluoride and methanol in a molar ratio of 1.05:1 in the step (1);
the second difference is that: the reaction temperature in the reaction tube in the step (3) is 300 ℃ and the contact time is 15s.
Calculation of CH prepared by examples 1-6 3 The yield of F is shown in Table 1.
Table 1 yields of monofluoromethane prepared in examples 1 to 6
| Examples | HF/CH 3 OH molar ratio | Reaction temperature/. Degree.C | Contact time/s | CH 3 F yield/% | CH 3 F yield calculation benchmark |
| 1 | 1.1 | 320 | 20 | 91.4 | By CH 3 OH meter |
| 2 | 1.05 | 350 | 15 | 95.2 | By CH 3 OH meter |
| 3 | 1.0 | 320 | 20 | 92.1 | By CH 3 OH meter |
| 4 | 0.95 | 350 | 15 | 93.7 | Calculated as HF |
| 5 | 0.9 | 320 | 15 | 91.6 | Calculated as HF |
| 6 | 1.05 | 300 | 15 | 88.9 | By CH 3 OH meter |
Effect example 1 influence of reaction temperature on yield of monofluoromethane
From the data in table 1, it is clear that comparative examples 2 and 6 can greatly improve the yield of monofluoromethane by increasing the reaction temperature in the reaction tube under the same reaction conditions, and the yield is improved from 88.9% to 95.2%, which shows that the change of the reaction temperature in the reaction tube has a great influence on the method for preparing monofluoromethane based on methanol provided by the invention.
Effect example 2 influence of the molar ratio of Hydrogen fluoride and methanol as raw materials on yield of monofluoromethane
In comparative examples 2 and 4, the molar ratio of raw material hydrogen fluoride to methanol is improved under the same reaction condition, the yield of monofluoromethane is improved by a small margin, and the yield is improved from 93.7% to 95.2% and only improved by 1.5%; in addition, in comparative examples 1 and 3, under the same reaction conditions, the molar ratio of hydrogen fluoride to methanol as raw materials was increased, but the yield of monofluoromethane could not be increased, and the yield was reduced from 92.1% to 91.4%; finally, comparative examples 5 and 6, example 5 increased the reaction temperature in the reaction tube while decreasing the molar ratio of hydrogen fluoride to methanol relative to example 6, but did not result in an increase in the yield of monofluoromethane, indicating that the reaction temperature in the reaction tube had a greater effect on the yield of a methanol-based process for producing monofluoromethane than the molar ratio of starting materials hydrogen fluoride to methanol.
Effect example 3 influence of contact time on yield of monofluoromethane
Comparative examples 1 and 2, example 2 increased the reaction temperature in the reaction tube while decreasing the molar ratio of hydrogen fluoride to methanol relative to example 1, decreased the contact time of the catalyst in the reaction tube, but did not pull down the yield of monofluoromethane, indicating that the reaction temperature in the reaction tube had a greater effect on the yield of a methanol-based process for producing monofluoromethane than the molar ratio of hydrogen fluoride and methanol as the starting materials and the contact time.
In summary, according to the embodiment of the method for preparing the monofluoromethane based on the methanol, the reaction temperature in the reaction tube is controlled to be more than 320 ℃, so that the yield of the monofluoromethane can be improved to be more than 91.4%. Thus, by a simple preparation process, a higher conversion can be obtained in the preparation of monofluoromethane based on readily available raw materials methanol and hydrogen fluoride. In addition, as unreacted raw materials in the reaction process of the methanol and the hydrogen fluoride can be used as a first-stage tower kettle component and returned to the reactor for continuous reaction, the three wastes generated in the preparation process are less.
Finally, the preparation by examples 1 to 6 was carried out according to the national standard GB/T40418-2021 electronic Tegaku fluoromethane test and calculatedThe CH obtained 3 The purity of F is shown in Table 2.
Table 2 purity of monofluoromethane prepared in examples 1 to 6
As can be seen from the data in the table 2, the invention provides a method for preparing monofluoromethane based on methanol, which takes methanol as a raw material, reacts with hydrogen fluoride, and unreacted raw material in the reaction process can be returned to a reactor for continuous reaction, and the generated crude product is subjected to gas-liquid separation, drying, primary separation and secondary separation for purification, so that monofluoromethane with the purity of more than or equal to 99.999 is obtained.
The foregoing examples are illustrative of the present invention and are not intended to be limiting, and any other changes, modifications, substitutions, combinations, or simplifications that do not depart from the spirit and principles of the invention are intended to be equivalent arrangements which are within the scope of the invention.
The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application to thereby enable one skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. A method for preparing monofluoromethane based on methanol, which is characterized by comprising the following steps:
(1) Dewatering the methanol and/or the first-stage tower kettle component through a liquid dryer;
(2) Vaporizing the dehydrated methanol and/or the first-stage tower kettle component by a vaporizer, and introducing the vaporized methanol and/or the first-stage tower kettle component into a mixer; meanwhile, anhydrous hydrogen fluoride is preheated by a preheater and is introduced into a mixer for mixing;
(3) Introducing hydrogen fluoride and methanol mixed in the step (2) according to the molar ratio of (0.9-1.1) to a reaction tube filled with a catalyst for reaction to obtain a crude product;
(4) The crude product enters a gas-liquid separator for separation;
(5) Introducing the gas separated in the step (4) into a gas dryer for dehydration treatment;
(6) Introducing the dehydrated gas into a first-stage separation tower to separate to form a first-stage tower top component and a first-stage tower kettle component, and introducing the first-stage tower kettle component into a liquid dryer for recycling;
(7) The first-stage tower top component is introduced into a second-stage separation tower to be separated to form a second-stage tower top component and a second-stage tower bottom component, and the second-stage tower top component enters a product collecting tank.
2. The process according to claim 1, wherein the vaporization temperature of the vaporizer in the step (2) is set to 70 to 100 ℃.
3. The process according to claim 1, wherein the preheating temperature of the preheater in the step (2) is set to 80 to 120 ℃.
4. The process according to claim 1, wherein the reaction temperature in the reaction tube in the step (3) is set to 200 to 500 ℃.
5. The method of claim 1, wherein the liquid dryer is filled with a 3A molecular sieve, a 4A molecular sieve, a 5A molecular sieve or a 13X molecular sieve, and the gas dryer is filled with spherical or rod-shaped activated carbon.
6. The process according to claim 1, wherein the first-stage separation column in step (6) has a top temperature of 0 to 10℃and a bottom temperature of-20 to 0℃and the second-stage separation column in step (7) has a top temperature of-45 to-35℃and a bottom temperature of-100 to-80 ℃.
7. The process of claim 1, wherein the bottom of the primary separation column in step (6) is in communication with the liquid inlet of the liquid dryer.
8. The production method according to any one of claims 1 to 7, wherein the catalyst in the step (3) is a supported catalyst, the carrier of the supported catalyst is an active carbon carrier, and the active components supported on the active carbon carrier include (0.5 to 5) in mass ratio: 1 chromium fluoride and zinc fluoride.
9. The method of preparing of claim 8, wherein the catalytic promoter in the active component comprises one or more of cobalt, nickel, copper, manganese, or tin fluorides.
10. The method according to claim 8, wherein the catalyst auxiliary in the active component accounts for 0.1 to 5% of the total mass of the active component.
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