CN116496138B - Preparation method and preparation device system of monofluoromethane - Google Patents
Preparation method and preparation device system of monofluoromethane Download PDFInfo
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- CN116496138B CN116496138B CN202310724128.1A CN202310724128A CN116496138B CN 116496138 B CN116496138 B CN 116496138B CN 202310724128 A CN202310724128 A CN 202310724128A CN 116496138 B CN116496138 B CN 116496138B
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- dimethyl carbonate
- crown ether
- alkali metal
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- NBVXSUQYWXRMNV-UHFFFAOYSA-N monofluoromethane Natural products FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 title claims abstract description 140
- 238000002360 preparation method Methods 0.000 title claims abstract description 95
- 238000006243 chemical reaction Methods 0.000 claims abstract description 179
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims abstract description 152
- 239000006227 byproduct Substances 0.000 claims abstract description 93
- 150000003983 crown ethers Chemical class 0.000 claims abstract description 87
- 229910001515 alkali metal fluoride Inorganic materials 0.000 claims abstract description 62
- 238000004519 manufacturing process Methods 0.000 claims abstract description 48
- 239000007789 gas Substances 0.000 claims description 268
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 107
- 238000011084 recovery Methods 0.000 claims description 88
- 229910052757 nitrogen Inorganic materials 0.000 claims description 53
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 claims description 48
- 238000010992 reflux Methods 0.000 claims description 44
- 239000002994 raw material Substances 0.000 claims description 37
- 238000003756 stirring Methods 0.000 claims description 35
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 claims description 34
- 238000002156 mixing Methods 0.000 claims description 31
- 238000004821 distillation Methods 0.000 claims description 30
- 239000007788 liquid Substances 0.000 claims description 28
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 claims description 28
- 238000010438 heat treatment Methods 0.000 claims description 27
- 238000004140 cleaning Methods 0.000 claims description 25
- 238000000034 method Methods 0.000 claims description 23
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 claims description 20
- 235000013024 sodium fluoride Nutrition 0.000 claims description 17
- 239000011775 sodium fluoride Substances 0.000 claims description 17
- 239000002699 waste material Substances 0.000 claims description 17
- 239000011698 potassium fluoride Substances 0.000 claims description 15
- 238000010521 absorption reaction Methods 0.000 claims description 14
- 235000003270 potassium fluoride Nutrition 0.000 claims description 14
- XEZNGIUYQVAUSS-UHFFFAOYSA-N 18-crown-6 Chemical compound C1COCCOCCOCCOCCOCCO1 XEZNGIUYQVAUSS-UHFFFAOYSA-N 0.000 claims description 12
- 229910001413 alkali metal ion Inorganic materials 0.000 claims description 12
- 229940050176 methyl chloride Drugs 0.000 claims description 11
- FBBDOOHMGLLEGJ-UHFFFAOYSA-N methane;hydrochloride Chemical compound C.Cl FBBDOOHMGLLEGJ-UHFFFAOYSA-N 0.000 claims description 9
- 238000003860 storage Methods 0.000 claims description 9
- 229910001873 dinitrogen Inorganic materials 0.000 claims 1
- 239000003960 organic solvent Substances 0.000 abstract description 19
- 239000002904 solvent Substances 0.000 abstract description 15
- 239000000047 product Substances 0.000 abstract description 12
- 238000000746 purification Methods 0.000 abstract description 9
- 238000013341 scale-up Methods 0.000 abstract description 9
- 239000012535 impurity Substances 0.000 abstract description 6
- 239000000376 reactant Substances 0.000 abstract description 6
- 238000003408 phase transfer catalysis Methods 0.000 abstract description 5
- 238000011112 process operation Methods 0.000 abstract description 4
- CXHHBNMLPJOKQD-UHFFFAOYSA-N methyl hydrogen carbonate Chemical class COC(O)=O CXHHBNMLPJOKQD-UHFFFAOYSA-N 0.000 description 25
- 239000007787 solid Substances 0.000 description 16
- 239000003054 catalyst Substances 0.000 description 15
- 239000000463 material Substances 0.000 description 13
- VFTFKUDGYRBSAL-UHFFFAOYSA-N 15-crown-5 Chemical compound C1COCCOCCOCCOCCO1 VFTFKUDGYRBSAL-UHFFFAOYSA-N 0.000 description 11
- 239000012071 phase Substances 0.000 description 11
- 238000004064 recycling Methods 0.000 description 9
- 239000000725 suspension Substances 0.000 description 9
- XQQZRZQVBFHBHL-UHFFFAOYSA-N 12-crown-4 Chemical compound C1COCCOCCOCCO1 XQQZRZQVBFHBHL-UHFFFAOYSA-N 0.000 description 8
- 230000007797 corrosion Effects 0.000 description 7
- 238000005260 corrosion Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 238000011010 flushing procedure Methods 0.000 description 6
- 231100000086 high toxicity Toxicity 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 239000007791 liquid phase Substances 0.000 description 5
- 229910001512 metal fluoride Inorganic materials 0.000 description 5
- 125000005911 methyl carbonate group Chemical group 0.000 description 5
- 238000000926 separation method Methods 0.000 description 5
- 238000009835 boiling Methods 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 230000006837 decompression Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 150000004673 fluoride salts Chemical class 0.000 description 4
- 239000013067 intermediate product Substances 0.000 description 4
- 239000003444 phase transfer catalyst Substances 0.000 description 4
- 229910001414 potassium ion Inorganic materials 0.000 description 4
- ZUHZGEOKBKGPSW-UHFFFAOYSA-N tetraglyme Chemical compound COCCOCCOCCOCCOC ZUHZGEOKBKGPSW-UHFFFAOYSA-N 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 3
- 150000001340 alkali metals Chemical class 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- CXHHBNMLPJOKQD-UHFFFAOYSA-M methyl carbonate Chemical compound COC([O-])=O CXHHBNMLPJOKQD-UHFFFAOYSA-M 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 230000001502 supplementing effect Effects 0.000 description 3
- 108010004350 tyrosine-rich amelogenin polypeptide Proteins 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 229940091249 fluoride supplement Drugs 0.000 description 2
- 238000003682 fluorination reaction Methods 0.000 description 2
- 150000002221 fluorine Chemical class 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 150000004702 methyl esters Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 230000001172 regenerating effect Effects 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- XWCDCDSDNJVCLO-UHFFFAOYSA-N Chlorofluoromethane Chemical compound FCCl XWCDCDSDNJVCLO-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- HXELGNKCCDGMMN-UHFFFAOYSA-N [F].[Cl] Chemical group [F].[Cl] HXELGNKCCDGMMN-UHFFFAOYSA-N 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910001514 alkali metal chloride Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000711 cancerogenic effect Effects 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 231100000315 carcinogenic Toxicity 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 229940071498 combination fluoride Drugs 0.000 description 1
- 229940073713 combination sodium fluoride Drugs 0.000 description 1
- 238000006298 dechlorination reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- UMNKXPULIDJLSU-UHFFFAOYSA-N dichlorofluoromethane Chemical compound FC(Cl)Cl UMNKXPULIDJLSU-UHFFFAOYSA-N 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical group 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- -1 methyl chloride, crown ether Chemical class 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 230000009965 odorless effect Effects 0.000 description 1
- 239000010815 organic waste Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000011973 solid acid Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 238000010792 warming Methods 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/10—Vacuum distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
- B01D5/0033—Other features
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
- B01D5/0057—Condensation of vapours; Recovering volatile solvents by condensation in combination with other processes
- B01D5/006—Condensation of vapours; Recovering volatile solvents by condensation in combination with other processes with evaporation or distillation
- B01D5/0063—Reflux condensation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
- B01J31/0201—Oxygen-containing compounds
- B01J31/0204—Ethers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J7/00—Apparatus for generating gases
- B01J7/02—Apparatus for generating gases by wet methods
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C19/00—Acyclic saturated compounds containing halogen atoms
- C07C19/08—Acyclic saturated compounds containing halogen atoms containing fluorine
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2231/00—Catalytic reactions performed with catalysts classified in B01J31/00
- B01J2231/40—Substitution reactions at carbon centres, e.g. C-C or C-X, i.e. carbon-hetero atom, cross-coupling, C-H activation or ring-opening reactions
- B01J2231/42—Catalytic cross-coupling, i.e. connection of previously not connected C-atoms or C- and X-atoms without rearrangement
- B01J2231/4277—C-X Cross-coupling, e.g. nucleophilic aromatic amination, alkoxylation or analogues
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention relates to a preparation method and a preparation device system of monofluoromethane, wherein the preparation method adopts a technical route that dimethyl carbonate and alkali metal fluoride are used for preparing monofluoromethane under the phase transfer catalysis of crown ether, and in the reaction, the dimethyl carbonate is not only a reactant, but also a solvent for dispersing the alkali metal fluoride, so that the use of an organic solvent is avoided; the preparation method provided by the invention has the advantages of rapid reaction, less byproducts and convenient purification. The preparation device system provided by the invention corresponds to the preparation method, can safely, stably and reliably produce the monofluoromethane product with few impurities and convenient purification, has simple process operation, and is suitable for industrial scale-up production.
Description
Technical Field
The invention belongs to the technical field of preparation of special gas, relates to a preparation method and a preparation device system of fluorine-containing special gas, and particularly relates to a preparation method and a preparation device system of monofluoromethane.
Background
Monofluoromethane (CH) 3 F) The code is HFC-41 or R41, the boiling point is-78.2 ℃, and the product is colorless, odorless and nontoxic inflammable gas under the standard condition, and has lower global warming potential value and zero ozone depletion potential value. High purity CH in integrated circuit fabrication 3 F (purity not less than 99.999 vol%) as Si 3 N 4 For SiO 2 And Si has a high selectivity, and is of interest in etching of fine structures in the prior process, and is commonly used in the fabrication of 3D NAND, DRAM, and FinFET semiconductor devices.
The synthesis method of the monofluoromethane in the prior art mainly comprises the following steps:
the method comprises the following steps:
by CH 3 Cl is used as a raw material, and is subjected to fluorine-chlorine exchange with HF under the catalysis of solid acid to prepare CH 3 F. The method requires multiple times of unreacted CH in the product 3 Cl and HF circulate to the reactor filled with the catalyst to continue the reaction, the process is complex, and the production difficulty is increased.
Although the reaction condition of the method is simple, the conversion efficiency is low, the equipment corrosion is serious, and HCl, HF, CH 3 Cl、CH 2 FCl、CH 4 Or C 2 H 4 And the gas phase byproducts are more, and the separation and purification of the products are difficult. Especially when mixed with CF 3 H and C 2 F 6 When fluorocarbon impurities are removed, CH is disturbed 3 F, the carbon-fluorine ratio in the etching process seriously affects the etching effect; and C 2 F 6 The boiling point of (2) is similar to that of monofluoromethane, and is difficult to thoroughly remove by conventional separation means such as rectification and the like; methane as a byproduct is easily attached to the surface of the catalyst, so that carbon deposition in pore channels is caused, the catalytic activity is reduced, and the production cost is raised.
The second method is as follows:
in CHFCl 2 Or CH (CH) 2 FCl as raw material, and H 2 Catalytic dechlorination hydrogenation reaction to prepare CH 3 F, the catalyst used in the method is expensive, the service life of the catalyst used at present is short, the selectivity is low, the product contains a large amount of corrosive gas and various halogen substituted products, and the separation and the purification are difficult; in addition, with the international society, ozone depletion substances and high temperature room effect gases (GWP 100)>150 For which the raw material HCFC-21 or HCFC-31 is difficult to obtain;
and a third method:
by CH 3 OH or CH 3 OCH 3 Preparing CH by reacting with HF under catalysis of metal fluoride 3 F. The method has low conversion rateA large amount of byproduct water is produced in the reaction process, so that the fluorination catalyst is deteriorated, and the catalytic activity of the fluorination catalyst is reduced; in addition, water forms mixed acid with anhydrous HF, severely corroding equipment, and it is difficult to separate out anhydrous HF, resulting in the inability of HF to be recycled.
The method four:
by (CH) 3 ) 2 SO 4 Or (CH) 3 ) 2 CO 3 As raw material, reacts with KF or NaF to prepare CH 3 The method has the advantages of simple reaction conditions, less gas impurities and easy purification to an electronic grade. But (CH) 3 ) 2 SO 4 Is a high-toxic compound, has cancerogenic potential and is limited in industrial production. (CH) 3 ) 2 CO 3 Although the toxicity of the fluorine salt is low, as described in CN112898114A, the reactivity of the fluorine salt in the liquid phase is poor, the reaction time is long, the conversion rate and the yield are extremely low, a large amount of solvent is needed to promote the reaction, and a large amount of organic waste liquid is needed to be treated.
CN114349593a improves (CH 3 ) 2 CO 3 With alkali metal fluoride, which will (CH 3 ) 2 CO 3 The catalyst is evaporated into gas phase and is introduced into a reactor loaded with alkali metal fluoride catalyst for reaction, the catalyst is required to be replaced frequently, and although the fluoride catalyst can be regenerated by HF gas, a large amount of water is inevitably generated when the catalyst is regenerated, and mixed acid is formed by the water and anhydrous HF, so that equipment is severely corroded, the anhydrous HF is difficult to separate, the HF cannot be recycled, and the reliability of the regenerated catalyst is required to be further verified. Moreover, the conditions for preparing and regenerating the catalyst are relatively complex, increasing the difficulty of scale-up production.
In this regard, it is necessary to provide a device capable of realizing high purity CH 3 F, a preparation method and a preparation device system for safely, stably and reliably producing the monofluoromethane.
Disclosure of Invention
The invention aims to provide a preparation method and a preparation device system of monofluoromethane, wherein the preparation method avoids the use of additional organic solvents, and has the advantages of rapid reaction, less byproducts and convenient purification; the preparation device system corresponds to the preparation method, can safely, stably and reliably produce the monofluoromethane product with few impurities and convenient purification, has simple process operation, and is suitable for industrial scale-up production.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a process for the preparation of monofluoromethane, the process comprising the steps of:
mixing crown ether, dimethyl carbonate and alkali metal fluoride, and heating for reaction to obtain monofluoromethane gas;
the diameter of the hole of the crown ether is more than or equal to the diameter of alkali metal ions in the alkali metal fluoride.
The fact that the diameter of the holes of the crown ether is larger than or equal to the diameter of the alkali metal ions in the alkali metal fluoride means that the holes with the diameter larger than or equal to the diameter of the alkali metal ions in the alkali metal fluoride exist in the crown ether, and the diameters of all the holes in the crown ether are not required to be larger than or equal to the diameter of the alkali metal ions in the alkali metal fluoride.
The preparation method provided by the invention adopts a technical route for preparing the monofluoromethane by liquid phase reaction of the dimethyl carbonate and the alkali metal fluoride under the phase transfer catalysis of crown ether, wherein the dimethyl carbonate is a reactant and a solvent for dispersing the alkali metal fluoride, so that the use of an organic solvent is avoided.
Furthermore, the crown ether may form stable complexes with the alkali metal of the alkali metal fluoride, which property of the crown ether may dissolve the corresponding alkali metal fluoride in an organic solvent, unsolvated F - Free of alkali counter-ions, thereby being present in bare form in the solvent, F - Is extremely active. The invention adopts crown ether as phase transfer catalyst, which can make the reaction difficult to occur under the traditional condition proceed smoothly. For example, the reaction of dimethyl carbonate with alkali metal fluoride requires a large amount of organic solvent to aid in dispersing alkali metal fluoride salt due to F - Most exist in pairs with counter-alkali metal ions and therefore are not sufficiently reactive, and it is necessary to raise the temperature to 120 to 200℃to promote the reaction, even though the reaction rate is still lowAnd the conversion rate is not high. The present invention effectively overcomes the above-mentioned drawbacks by the use of crown ethers.
Preferably, the crown ether comprises any one or a combination of at least two of 12-crown ether-4, 15-crown ether-5 or 18-crown ether-6.
Preferably, the crown ether is 0.5% to 10% of the molar amount of alkali metal fluoride.
Preferably, the alkali metal fluoride comprises any one or a combination of at least two of lithium fluoride, sodium fluoride or potassium fluoride.
Preferably, the molar ratio of alkali metal fluoride to dimethyl carbonate is from 1:3 to 1:10.
Preferably, the temperature of the heating reaction is from 40 ℃ to 100 ℃;
Preferably, the heating reaction is carried out with stirring at a rate of 30rpm to 150rpm.
Preferably, the preparation method comprises the following steps:
(1) Mixing crown ether, dimethyl carbonate and alkali metal fluoride, and heating for reaction to obtain monofluoromethane gas and reacted feed liquid;
(2) Separating and recovering crown ether in the reacted feed liquid obtained in the step (1) to obtain separated feed liquid; and then mixing and separating the feed liquid and excessive chloromethane, and reacting to obtain the dimethyl carbonate.
Crown ether, dimethyl carbonate and alkali metal fluoride react to produce methyl carbonate as by-product in addition to methyl monofluoride gas. The byproduct methyl carbonate salt is reacted with methyl chloride to convert to dimethyl carbonate. As a preferred embodiment, the dimethyl carbonate obtained by the reaction can be used as a raw material for preparing methane chloride gas.
In the preparation method provided by the invention, no harsh corrosion and high toxicity raw materials are introduced and products are generated, the use of an organic solvent is avoided, the monofluoromethane product with low impurity content and convenient purification can be safely, stably and reliably produced, the process operation is simple, and the preparation method is suitable for industrial scale-up production.
Preferably, the molar ratio of the methyl chloride of step (2) to the alkali metal fluoride of step (1) is from 1.5:1 to 4:1.
Preferably, the temperature of the reaction of step (2) is from 80 ℃ to 170 ℃.
Preferably, the reaction of step (2) takes from 1 to 4 hours.
Preferably, the reaction of step (2) is carried out with stirring at a rate of from 30rpm to 150rpm.
In a second aspect, the present invention provides a production apparatus system for the production method of the first aspect, the production apparatus system comprising a gas generation unit, a rectification unit, and a nitrogen cleaning unit;
the gas generating unit comprises a gas generating device, a mixing device, a reflux condensing device and a crude gas cold trap; the discharge port of the mixing device is connected with the feed port of the gas generating device; the top exhaust port of the gas generating device is connected with the reflux condensing device; the discharge port of the reflux condensing device is connected with a crude gas cold trap;
the rectification unit comprises a first rectification tower, a heavy phase storage tank and a pure gas cold trap; the feed inlet of the first rectifying tower is connected with the discharge outlet of the crude gas cold trap; the bottom discharge pipeline of the first rectifying tower is connected with the heavy phase storage tank, and the top discharge pipeline of the first rectifying tower is connected with the pure gas cold trap;
And a nitrogen pipeline of the nitrogen cleaning unit is connected with the mixing device and a connecting pipeline of the gas generating device.
The preparation device system provided by the invention corresponds to the preparation method, and has no harsh corrosion and high toxicity raw material introduction and intermediate product production in the whole production process of the monofluoromethane gas, so that the use of additional organic solvents is avoided, and the operation of the whole preparation device system is simple, thereby being suitable for industrial scale-up production.
The preparation device system provided by the invention is also provided with a necessary conveying device, the invention is not excessively limited herein, and a person skilled in the art can reasonably set the preparation device system according to the material conveying requirement.
When the monofluoromethane preparation device system provided by the invention is used for preparing monofluoromethane, the following steps are adopted:
s1: firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
s2: dispersing alkali metal fluoride and crown ether in a mixing device by using 1/2 to 2/3 of the total amount of the dimethyl carbonate, and then transferring the mixture into a gas generating device; flushing the mixing device with the rest dimethyl carbonate, and transferring flushing liquid to the gas generating device;
s3: maintaining the working temperatures of the reflux condensing device and the crude gas cold trap, and raising the working temperature of the gas generating device until the gas stably escapes; after the gas escape is reduced, the gas is refluxed by using a reflux condensing device until the gas is not escaped any more; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas meeting application requirements can be obtained in a pure gas cold trap.
Preferably, the production plant system further comprises a byproduct conversion unit;
the byproduct conversion unit comprises a byproduct conversion device, a chloromethane supply device, a circulating condensing device, a raw material gas recovery trap, a dimethyl carbonate recovery device, a waste recovery device and a tail gas absorption device;
the discharge port of the methane chloride supply device and the gas generation device are respectively connected with the feed port of the byproduct conversion device; the bottom discharge port of the byproduct conversion device is connected with the waste recovery device; the top discharge port of the byproduct conversion device is connected with the circulating condensing device, and the exhaust port of the circulating condensing device is sequentially connected with the raw material gas recovery trap and the tail gas absorbing device; the bottom liquid outlet of the circulating condensing device is connected with the dimethyl carbonate recovery device; the bottom liquid outlet connected with the dimethyl carbonate recovery device is connected with the top liquid inlet of the byproduct conversion device.
When the byproduct conversion unit is applied, the byproduct conversion unit comprises:
s4-1: materials in the gas generating device which do not escape gas are led into the byproduct conversion device, residual dimethyl carbonate is distilled off at normal pressure, and the residual dimethyl carbonate is collected in the dimethyl carbonate recovery device through the circulating condensing device; when the dimethyl carbonate is no longer distilled off, the crown ether is distilled off under reduced pressure; then adding the collected dimethyl carbonate into a byproduct conversion device, and dissolving and dispersing the rest methyl carbonate salt solid; after closing the discharging, introducing excessive methane chloride gas, and supplementing nitrogen to adjust the reaction pressure so as to replace methyl carbonate salt with dimethyl carbonate;
S5: the reaction is carried out until the pressure in the system is obviously reduced, then the temperature is reduced to room temperature, the escaped gas is collected in a raw material gas recovery trap through a circulating condensing device, the raw material gas recovery trap is also connected with a tail gas absorbing device, and the tail gas is treated by the tail gas absorbing device; then, completely distilling the dimethyl carbonate in the byproduct conversion device, and collecting the dimethyl carbonate in the dimethyl carbonate recovery device through a circulating condensing device; the residual white solid in the byproduct conversion device is removed and transferred to a waste recovery device.
The dimethyl carbonate recovered in the dimethyl carbonate recovery device can be reused for the preparation of the monofluoromethane gas.
Preferably, the nitrogen pipeline of the nitrogen cleaning unit is connected with the connecting pipeline of the chloromethane supply device and the byproduct conversion device.
Preferably, the nitrogen pipeline of the nitrogen cleaning unit is connected with the connecting pipeline of the gas generating device and the byproduct conversion device.
Preferably, the production plant system further comprises a reduced pressure distillation unit.
The reduced pressure distillation unit comprises a reduced pressure distillation device, a crown ether recovery device, a protection cold trap and a vacuum generation device;
the feed inlet of the reduced pressure distillation device is connected with a crown ether steam discharge pipeline of the byproduct conversion device; the bottom discharge port of the reduced pressure distillation device is connected with the crown ether recovery device, and the top discharge port of the reduced pressure distillation device is communicated with the vacuum generating device through a protection cold trap.
The reduced pressure distillation unit according to the present invention comprises:
s4-2: and recovering the crown ether distilled out by the decompression in the byproduct conversion device to a crown ether recovery device through the decompression distillation device.
The crown ether recovered in the crown ether recovery device can be used for the preparation of the monofluoromethane gas.
Preferably, the nitrogen pipeline of the nitrogen cleaning unit is connected with a connecting pipeline for protecting the cold trap and the vacuum generating device.
Preferably, stirring paddles are respectively and independently arranged in the mixing device, the gas generating device and the byproduct conversion device.
Compared with the prior art, the invention has the following beneficial effects:
(1) The preparation method provided by the invention adopts a technical route for preparing the monofluoromethane by liquid phase reaction of the dimethyl carbonate and the alkali metal fluoride under the phase transfer catalysis of crown ether, wherein the dimethyl carbonate is a reactant and a solvent for dispersing the alkali metal fluoride, so that the use of an organic solvent is avoided;
(2) The invention adopts crown ether as phase transfer catalyst, which can make the reaction difficult to occur under the traditional condition proceed smoothly. For example, the reaction of dimethyl carbonate with alkali metal fluoride requires a large amount of organic solvent to aid in dispersing alkali metal fluoride salt due to F - Most of the catalyst exists in pairs with the counter alkali metal ions, so that the reaction activity is insufficient, the temperature is increased to 120-200 ℃ to promote the reaction, and even if the reaction rate is still low and the conversion rate is not high, the invention effectively overcomes the defects through the use of crown ether;
(3) The preparation device system provided by the invention corresponds to the preparation method, and has no harsh corrosion and high toxicity raw material introduction and intermediate product production in the whole production process of the monofluoromethane gas, so that the use of additional organic solvents is avoided, and the operation of the whole preparation device system is simple, thereby being suitable for industrial scale-up production.
Drawings
FIG. 1 is a graph of 12-crown-4 and Li + Is a complex schematic diagram of (a);
FIG. 2 is 15-crown-5 and Na + Is a complex schematic diagram of (a);
FIG. 3 is a graph of 18-crown-6 and K + Is a complex schematic diagram of (a);
FIG. 4 is a schematic diagram of the material circulation in the preparation of monofluoromethane;
fig. 5 is a schematic structural diagram of a system of a device for preparing monofluoromethane according to embodiment 1 of the present invention.
Wherein: 11, a gas generating device; 12, a mixing device; 13, reflux condensing device; 14, a crude gas cold trap;
21, a first rectifying column; 22, a heavy phase storage tank; 23, pure gas cold trap;
31, a byproduct conversion device; 32, a chloromethane supply device; 33, a circulating condensing device; 34, a dimethyl carbonate recovery device; 35, a raw material gas recovery trap; 36, tail gas absorbing device; 37, a waste recycling device;
41, a reduced pressure distillation apparatus; 42, crown ether recovery unit; 43, protecting the cold trap; 44, vacuum generating means.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
An embodiment of the present invention provides a method for preparing monofluoromethane, the method comprising the steps of:
mixing crown ether, dimethyl carbonate and alkali metal fluoride, and heating for reaction to obtain monofluoromethane gas.
The preparation method provided by the invention adopts a technical route for preparing the monofluoromethane by liquid phase reaction of the dimethyl carbonate and the alkali metal fluoride under the phase transfer catalysis of crown ether, wherein the dimethyl carbonate is a reactant and a solvent for dispersing the alkali metal fluoride, so that the use of an organic solvent is avoided.
Furthermore, the crown ether may form stable complexes with the alkali metal of the alkali metal fluoride, which property of the crown ether may dissolve the corresponding alkali metal fluoride in an organic solvent, unsolvated F - Free of alkali counter-ions, thereby being present in bare form in the solvent, F - Is extremely active. The invention adopts crown ether as phase transfer catalyst, which can make the catalyst under the traditional conditionThe reaction which hardly occurs below proceeds smoothly. For example, the reaction of dimethyl carbonate with alkali metal fluoride requires a large amount of organic solvent to aid in dispersing alkali metal fluoride salt due to F - Most exist in pairs with counter-alkali metal ions and therefore are not sufficiently reactive, and it is also necessary to raise the temperature to 120 to 200 ℃ to facilitate the reaction, even though the reaction rate is still low and the conversion is not high. The present invention effectively overcomes the above-mentioned drawbacks by the use of crown ethers.
In certain embodiments, the crown ethers include any one or a combination of at least two of 12-crown-4, 15-crown-5, or 18-crown-6, including, typically but not limited to, a combination of 12-crown-4 with 15-crown-5, a combination of 15-crown-5 with 18-crown-6, a combination of 12-crown-4 with 18-crown-6, or a combination of 12-crown-4, 15-crown-5 with 18-crown-6.
The crown ether of the present invention forms stable complexes with alkali metal ions in alkali metal fluorides, e.g., 12-crown ether-4 having a pore diameter of 1.2A to 1.5A, capable of interacting with Li + Forming a stable complex (see fig. 1); 15-crown-5 has a pore diameter of 1.7A to 2.2A, capable of reacting with Na + Forming a stable complex (see fig. 2); the diameter of the hole of the 18-crown ether-6 is 2.6A to 3.2A, and can be matched with K + A stable complex is formed (see fig. 3).
In certain embodiments, the crown ether is 0.5% to 10% of the molar amount of alkali metal fluoride, which may be, for example, 0.5%, 1%, 2%, 3%, 5%, 6%, 8% or 10%, but is not limited to the recited values, as are other non-recited values within the range of values.
When the molar amount of crown ether is less than 0.5% based on alkali metal fluoride, F is released in the reaction system - Insufficient, slow reaction rate, CH 3 F, the generation efficiency of the gas is low; when the crown ether accounts for more than 10% of the molar amount of the alkali metal fluoride, CH 3 The rate of F gas formation is too fast, resulting in a reaction that is not easily controlled, and excessive amounts of crown ether also increase the difficulty of subsequent recovery.
In certain embodiments, the alkali metal fluoride comprises any one or a combination of at least two of lithium fluoride, sodium fluoride, or potassium fluoride, and typical but non-limiting combinations include combinations of lithium fluoride and sodium fluoride, combinations of sodium fluoride and potassium fluoride, combinations of lithium fluoride and potassium fluoride, or combinations of lithium fluoride, sodium fluoride, and potassium fluoride.
In certain embodiments, the molar ratio of alkali metal fluoride to dimethyl carbonate is 1:3 to 1:10, and may be, for example, 1:3, 1:4, 1:5, 1:6, 1:8, or 1:10, but is not limited to the recited values, as are other non-recited values within the range of values.
Theoretically, when an alkali Metal Fluoride (MF) is mixed with dimethyl carbonate ((CH) 3 ) 2 CO 3 ) When the molar ratio of the feed is greater than 2:1, CH is generated 3 F, also generates carbonate (M) 2 CO 3 ) The reaction formula is as follows:
however, this reaction requires the addition of a sufficient solvent (e.g., a high boiling point ether solvent such as tetraethylene glycol dimethyl ether) to disperse the carbonate, which would otherwise tend to agglomerate and affect further reaction and safety. However, the boiling point of the common solvent (such as tetraethylene glycol dimethyl ether) is not greatly different from that of crown ether, the chemical structure is similar, and the separation difficulty in the post-treatment is increased. In addition, the additional solvent also dilutes the reaction concentration of dimethyl carbonate, reducing the reaction rate. The dimethyl carbonate in the invention is not only a reactant, but also a solvent for dispersing alkali metal fluoride, so that the use of an organic solvent is avoided.
When an alkali Metal Fluoride (MF) is mixed with dimethyl carbonate ((CH) 3 ) 2 CO 3 ) When the feed molar ratio of (2) is less than 1:1, the product is other than CH 3 F (CH) 3 ) 2 CO 3 The conversion of (C) is mainly methyl carbonate salt (CH) 3 OCOOM), the reaction equation is as follows:
alkali Metal Fluoride (MF) and dimethyl carbonate (-), dimethyl carbonateCH 3 ) 2 CO 3 ) Is F as a fluorine ion - Para-methyl ester carbon-OCH 3 When dimethyl carbonate ((CH) 3 ) 2 CO 3 ) After the reaction of one methyl ester carbon site, the activity of the other methyl ester carbon site of the generated methyl carbonate salt is weakened; free F when sufficient dimethyl carbonate is present - Tend to react with other dimethyl carbonate to form methyl carbonate salts rather than continuing to react with methyl carbonate salts to form carbonates. Thus, when the alkali Metal Fluoride (MF) is mixed with dimethyl carbonate ((CH) 3 ) 2 CO 3 ) When the feeding molar ratio is less than 1:1, methyl carbonate salt is mainly generated.
When dimethyl carbonate ((CH) 3 ) 2 CO 3 ) When the feeding amount is too large, the proportion of methyl carbonate salt generated in the reaction system is too large, and the methyl carbonate salt is easy to agglomerate when no additional solvent is added, so that the safety of the reaction is affected; the additional addition of solvent increases the difficulty of post-treatment. When dimethyl carbonate ((CH) 3 ) 2 CO 3 ) When the feeding amount of (2) is too small, the system can well disperse methyl carbonate salt, and the alkali metal fluoride completely reacts, but the CH produced in a single batch is produced 3 F gas is little, and the production efficiency is low. Therefore, the molar ratio of alkali metal fluoride to dimethyl carbonate is preferably 1:3 to 1:10.
In some embodiments, the heating reaction temperature is 40 ℃ to 100 ℃, for example, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, or 100 ℃, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.
When the temperature of the heating reaction is lower than 40 ℃, the reaction rate is slower, CH 3 The generation efficiency of F gas is low; when the temperature of the heating reaction is higher than 100 ℃, the free F is accelerated - But at this time, the complex ion of crown ether and alkali metal has a risk of dissociation, and the dimethyl carbonate is in a bumping state and is not easy to control.
In certain embodiments, the heating reaction is carried out with stirring at a rate of 30rpm to 150rpm, which may be, for example, 30rpm, 50rpm, 60rpm, 80rpm, 100rpm, 120rpm, or 150rpm, but is not limited to the recited values, as other non-recited values within the range of values are equally applicable.
In some embodiments, a schematic material circulation diagram of the preparation method is shown in fig. 4, and the method comprises the following steps:
(1) Mixing crown ether, dimethyl carbonate and alkali metal fluoride, and heating for reaction to obtain monofluoromethane gas and reacted feed liquid;
(2) Separating and recovering crown ether in the reacted feed liquid obtained in the step (1) to obtain separated feed liquid; and then mixing and separating the feed liquid and excessive chloromethane, and reacting to obtain the dimethyl carbonate.
Crown ether, dimethyl carbonate and alkali metal fluoride react to produce methyl carbonate as by-product in addition to methyl monofluoride gas. The byproduct methyl carbonate salt is reacted with methyl chloride to convert to dimethyl carbonate. As a preferred embodiment, the dimethyl carbonate obtained by the reaction can be used as a raw material for preparing methane chloride gas.
In the preparation method provided by the invention, no harsh corrosion and high toxicity raw materials are introduced and products are generated, the use of an organic solvent is avoided, the monofluoromethane product with low impurity content and convenient purification can be safely, stably and reliably produced, the process operation is simple, and the preparation method is suitable for industrial scale-up production.
The crown ether is complexed with alkali metal ions to increase the liberation of chloride ions, thereby reducing the aggregation and precipitation of alkali metal chlorides and affecting the forward progress of the reaction. Therefore, in the process of regenerating dimethyl carbonate by converting methyl carbonate salt with methyl chloride, crown ether needs to be removed firstly, and then the following reaction is carried out:
in certain embodiments, the molar ratio of the methyl chloride of step (2) to the alkali metal fluoride of step (1) is from 1.5:1 to 4:1, and may be, for example, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, or 4:1, but is not limited to the recited values, as are other non-recited values within the range of values.
In certain embodiments, the temperature of the reaction described in step (2) is from 80 ℃ to 170 ℃, such as 80 ℃, 90 ℃, 100 ℃, 120 ℃, 150 ℃, 160 ℃, or 170 ℃, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.
Increasing the pressure of the reaction described in step (2) is advantageous for the reaction, but requires a relatively high level of equipment. Under the reaction temperature conditions of the step (2) of the present invention, the pressure of the reaction ranges from 3bar to 8bar, and the reaction of the step (2) can be smoothly carried out within the pressure range.
In certain embodiments, the reaction of step (2) is carried out for a period of time ranging from 1h to 4h, such as 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, or 4h, although not limited to the recited values, and other non-recited values within the range of values are equally applicable.
In certain embodiments, the reaction of step (2) is carried out with stirring at a rate of 30rpm to 150rpm, which may be, for example, 30rpm, 50rpm, 60rpm, 80rpm, 100rpm, 120rpm, or 150rpm, but is not limited to the recited values, as are other non-recited values within the range of values.
An embodiment of the present invention provides a system for preparing a monofluoromethane, the system for preparing a monofluoromethane comprising a gas generating unit, a rectifying unit, and a nitrogen cleaning unit;
the gas generating unit comprises a gas generating device, a mixing device, a reflux condensing device and a crude gas cold trap; the discharge port of the mixing device is connected with the feed port of the gas generating device; the top exhaust port of the gas generating device is connected with the reflux condensing device; the discharge port of the reflux condensing device is connected with a crude gas cold trap;
The rectification unit comprises a first rectification tower, a heavy phase storage tank and a pure gas cold trap; the feed inlet of the first rectifying tower is connected with the discharge outlet of the crude gas cold trap; the bottom discharge pipeline of the first rectifying tower is connected with the heavy phase storage tank, and the top discharge pipeline of the first rectifying tower is connected with the pure gas cold trap;
and a nitrogen pipeline of the nitrogen cleaning unit is connected with the mixing device and a connecting pipeline of the gas generating device.
The preparation device system provided by the invention corresponds to the preparation method, and has no harsh corrosion and high toxicity raw material introduction and intermediate product production in the whole production process of the monofluoromethane gas, so that the use of additional organic solvents is avoided, and the operation of the whole preparation device system is simple, thereby being suitable for industrial scale-up production.
When the monofluoromethane preparation device system provided by the invention is used for preparing monofluoromethane, the following steps are adopted:
s1: firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
s2: dispersing alkali metal fluoride and crown ether in a mixing device by using 1/2 to 2/3 of the total amount of the dimethyl carbonate, and then transferring the mixture into a gas generating device; flushing the mixing device with the rest dimethyl carbonate, and transferring flushing liquid to the gas generating device;
S3: maintaining the working temperatures of the reflux condensing device and the crude gas cold trap, and raising the working temperature of the gas generating device until the gas stably escapes; after the gas escape is reduced, the gas is refluxed by using a reflux condensing device until the gas is not escaped any more; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas meeting application requirements can be obtained in a pure gas cold trap.
CH is carried out by using the preparation device system provided by the invention 3 During the preparation of F, the byproduct is only methyl carbonate, and the crown ether catalyzed by phase transfer is difficult to volatilize, so that the main component of the gas collected in the crude gas cold trap through the reflux condensing device is CH 3 F, in addition, a small amount of dimethyl carbonate is mixed, and separation can be realized through simple rectification.
In certain embodiments, the production plant system further comprises a byproduct conversion unit;
the byproduct conversion unit comprises a byproduct conversion device, a chloromethane supply device, a circulating condensing device, a raw material gas recovery trap, a dimethyl carbonate recovery device, a waste recovery device and a tail gas absorption device;
the discharge port of the methane chloride supply device and the gas generation device are respectively connected with the feed port of the byproduct conversion device; the bottom discharge port of the byproduct conversion device is connected with the waste recovery device; the top discharge port of the byproduct conversion device is connected with the circulating condensing device, and the exhaust port of the circulating condensing device is sequentially connected with the raw material gas recovery trap and the tail gas absorbing device; the bottom liquid outlet of the circulating condensing device is connected with the dimethyl carbonate recovery device; the bottom liquid outlet connected with the dimethyl carbonate recovery device is connected with the top liquid inlet of the byproduct conversion device.
When the byproduct conversion unit is applied, the byproduct conversion unit comprises:
s4-1: materials in the gas generating device which do not escape gas are led into the byproduct conversion device, residual dimethyl carbonate is distilled off at normal pressure, and the residual dimethyl carbonate is collected in the dimethyl carbonate recovery device through the circulating condensing device; when the dimethyl carbonate is no longer distilled off, the crown ether is distilled off under reduced pressure; then adding the collected dimethyl carbonate into a byproduct conversion device, and dissolving and dispersing the rest methyl carbonate salt solid; after closing the discharging, introducing excessive methane chloride gas, and supplementing nitrogen to adjust the reaction pressure so as to replace methyl carbonate salt with dimethyl carbonate;
s5: the reaction is carried out until the pressure in the system is obviously reduced, then the temperature is reduced to room temperature, the escaped gas is collected in a raw material gas recovery trap through a circulating condensing device, the raw material gas recovery trap is also connected with a tail gas absorbing device, and the tail gas is treated by the tail gas absorbing device; then, completely distilling the dimethyl carbonate in the byproduct conversion device, and collecting the dimethyl carbonate in the dimethyl carbonate recovery device through a circulating condensing device; the residual white solid in the byproduct conversion device is removed and transferred to a waste recovery device.
The dimethyl carbonate recovered in the dimethyl carbonate recovery device can be reused for the preparation of the monofluoromethane gas.
In certain embodiments, the nitrogen line of the nitrogen cleaning unit is connected to the connection lines of the methyl chloride supply and the byproduct conversion device.
In certain embodiments, the nitrogen line of the nitrogen cleaning unit is connected to the connection lines of the gas generating device and the byproduct conversion device.
In certain embodiments, the production plant system further comprises a reduced pressure distillation unit.
The reduced pressure distillation unit comprises a reduced pressure distillation device, a crown ether recovery device, a protection cold trap and a vacuum generation device;
the feed inlet of the reduced pressure distillation device is connected with a crown ether steam discharge pipeline of the byproduct conversion device; the bottom discharge port of the reduced pressure distillation device is connected with the crown ether recovery device, and the top discharge port of the reduced pressure distillation device is communicated with the vacuum generating device through a protection cold trap.
The reduced pressure distillation unit according to the present invention comprises:
s4-2: and recovering the crown ether distilled out by the decompression in the byproduct conversion device to a crown ether recovery device through the decompression distillation device.
The crown ether recovered in the crown ether recovery device can be used for the preparation of the monofluoromethane gas.
For the sake of clarity of the description of the technical solution of the invention, the working temperature of the gas generating device in the system of the preparation device is, for example, 40 ℃ to 100 ℃; the working temperatures of the reflux condensing device, the circulating condensing device and the reduced pressure distilling device are-10 ℃ to 30 ℃; the working temperature of the crude gas cold trap and the pure gas cold trap is-100 ℃ to-80 ℃; the working temperature of the first rectifying tower is-40 ℃ to-20 ℃; the working temperature of the byproduct conversion device is 80-170 ℃; the working temperature of the feed gas recovery trap is-50 ℃ to-30 ℃.
In some embodiments, the nitrogen line of the nitrogen cleaning unit is connected to a connecting line that protects the cold trap and the vacuum generating device.
In some embodiments, the mixing device, the gas generating device and the byproduct converting device are respectively and independently provided with stirring paddles.
The stirring paddles include anchor type stirring paddles, frame type stirring paddles or impeller stirring paddles, and the invention is not particularly limited herein as long as uniform dispersion of materials can be achieved.
Example 1
In order to clearly illustrate the technical solution of the present invention and control the spread of the application document, the present embodiment provides a preparation apparatus system as shown in fig. 5, and the preparation method provided in the specific embodiment is performed in the preparation apparatus system provided in the present embodiment, where the preparation apparatus system includes a gas generating unit, a rectifying unit and a nitrogen cleaning unit;
the gas generating unit comprises a gas generating device 11, a mixing device 12, a reflux condensing device 13 and a crude gas cold trap 14; the discharge port of the mixing device 12 is connected with the feed port of the gas generating device 11; the top exhaust port of the gas generating device 11 is connected with a reflux condensing device 13; the discharge port of the reflux condensing device 13 is connected with a crude gas cold trap 14;
The rectification unit comprises a first rectification column 21, a heavy phase storage tank 22 and a pure gas cold trap 23; the feed inlet of the first rectifying tower 21 is connected with the discharge outlet of the crude gas cold trap 14; the bottom discharge pipeline of the first rectifying tower 21 is connected with a heavy phase storage tank 22, and the top discharge pipeline is connected with a pure gas cold trap 23;
the nitrogen pipeline of the nitrogen cleaning unit is connected with the connecting pipeline of the mixing device 12 and the gas generating device 11.
The production plant system further comprises a byproduct conversion unit; the byproduct conversion unit comprises a byproduct conversion device 31, a chloromethane supply device 32, a circulating condensing device 33, a raw material gas recovery trap 35, a dimethyl carbonate recovery device 34, a waste recovery device and a tail gas absorption device 36;
the discharge port of the methane chloride supply device 32 and the gas generation device 11 are respectively connected with the feed port of the byproduct conversion device 31; the bottom discharge port of the byproduct conversion device 31 is connected with a waste recycling device 37; the top discharge port of the byproduct conversion device 31 is connected with the circulating condensing device 33, and the exhaust port of the circulating condensing device 33 is sequentially connected with the raw material gas recovery trap 35 and the tail gas absorbing device 36; the bottom liquid outlet of the circulating condensing device 33 is connected with a dimethyl carbonate recovery device 34; the bottom liquid outlet connected with the dimethyl carbonate recovery device 34 is connected with the top liquid inlet of the byproduct conversion device 31;
The nitrogen pipeline of the nitrogen cleaning unit is connected with the connecting pipeline of the chloromethane supply device 32 and the byproduct conversion device 31;
the nitrogen pipeline of the nitrogen cleaning unit is connected with the connecting pipeline of the gas generating device 11 and the byproduct converting device 31;
the preparation device system also comprises a reduced pressure distillation unit; the reduced pressure distillation unit comprises a reduced pressure distillation device 41, a crown ether recovery device 42, a protective cold trap 43 and a vacuum generating device 44;
the feed inlet of the reduced pressure distillation device 41 is connected with a crown ether steam discharge pipeline of the byproduct conversion device 31; the bottom discharge port of the reduced pressure distillation device 41 is connected with a crown ether recovery device 42, and the top discharge port of the reduced pressure distillation device 41 is communicated with a vacuum generation device 44 through a protective cold trap 43;
the nitrogen pipeline of the nitrogen cleaning unit is connected with the connecting pipeline of the protection cold trap 43 and the vacuum generating device 44;
mixing device 12, gas generator 11 and byproduct converter 31 are each independently provided with stirring paddles.
When the preparation device system is used for preparing the monofluoromethane, the preparation device system comprises the following steps:
s1: firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
s2: in the mixing device 12, 1/2 to 2/3 of the total amount of dimethyl carbonate is used to disperse alkali metal fluoride and crown ether, and then transferred to the gas generating device 11; flushing the mixing device 12 with the rest dimethyl carbonate, and transferring the flushing liquid to the gas generating device 11;
S3: maintaining the working temperatures of the reflux condensing device 13 and the crude gas cold trap 14, and raising the working temperature of the gas generating device 11 until the gas stably escapes; after the gas escape is reduced, the reflux condensing device 13 is utilized to reflux the gas until the gas is not escaped any more; the escaped gas is collected in a crude gas cold trap 14 through a reflux condensing device 13, and is subjected to rectification treatment of a first rectifying tower 21, so that monofluoromethane gas meeting application requirements can be obtained in a pure gas cold trap 23;
s4: the materials in the gas generating device 11 without escaping gas are led into a byproduct converting device 31, the rest dimethyl carbonate is distilled off at normal pressure, and the materials are collected in a dimethyl carbonate recycling device 34 through a circulating condensing device 33; when the dimethyl carbonate is not distilled out any more, the crown ether is distilled out under reduced pressure, and the crown ether distilled out under reduced pressure in the by-product conversion device 31 is recovered to the crown ether recovery device 42 through the reduced pressure distillation device 41; the collected dimethyl carbonate is then added to a by-product conversion device 31 to dissolve and disperse the remaining methyl carbonate salt solids; after closing the discharging, introducing excessive methane chloride gas, and supplementing nitrogen to adjust the reaction pressure so as to replace methyl carbonate salt with dimethyl carbonate;
S5: the temperature is reduced to room temperature after the pressure in the system is obviously reduced, the escaped gas is collected in a raw material gas recovery trap 35 through a circulating condensing device 33, the raw material gas recovery trap 35 is also connected with a tail gas absorbing device 36, and the tail gas is treated by the tail gas absorbing device 36; the dimethyl carbonate in the byproduct conversion device 31 is completely distilled and is collected in a dimethyl carbonate recovery device 34 through a circulating condensing device 33; the white solid remaining in the by-product conversion device 31 is purged and transferred to the waste recovery device 37.
Application example 1
The application example provides a preparation method for preparing monofluoromethane by using the preparation device system provided in application example 1, wherein the preparation method comprises the following steps:
(a) Firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
(b) 12.23g (55.5 mmol) of 15-crown-5, 500g (5.55 mol) of dimethyl carbonate and 46.6g (1.11 mol) of sodium fluoride are dispersed in suspension under stirring at a stirring rate of 100rpm;
(c) Maintaining the working temperatures of the reflux condensing device and the crude gas cold trap, heating the reaction system to 60 ℃, ensuring stable escape of gas, reducing the escape of gas after 3 hours, and heating to 100 ℃ for reflux until the gas is fully escaped; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas can be obtained in a pure gas cold trap;
(d) The residual materials in the gas generating device are directly transferred into the byproduct conversion device without cooling, the stirring speed of 100rpm is maintained, the residual dimethyl carbonate is distilled off at normal pressure, and the residual dimethyl carbonate is collected in the dimethyl carbonate recovery device through the circulating condensing device; when the dimethyl carbonate is not distilled out any more, the crown ether is distilled out under reduced pressure and recycled to the crown ether recycling device; then adding the collected dimethyl carbonate into a byproduct conversion device, and dissolving and dispersing the rest methyl carbonate salt solid; after each discharge was closed, 112.1g (2.22 mol) of methyl chloride gas was introduced, nitrogen was supplemented and the temperature was raised to 120℃to a reaction system pressure of 6bar, whereby methyl carbonate salt was replaced with dimethyl carbonate;
(e) The reaction is carried out for 3 hours, the pressure in the system is obviously reduced, the temperature is reduced to the room temperature, the pressure is slowly released, and the escaped gas is collected in a raw material gas recovery trap through a circulating condensing device; the raw material gas recovery trap is also connected with a tail gas absorption device, and the tail gas is treated by the tail gas absorption device; then, completely distilling the dimethyl carbonate in the byproduct conversion device, and collecting the dimethyl carbonate in the dimethyl carbonate recovery device through a circulating condensing device; the residual white solid in the byproduct conversion device is removed and transferred to a waste recovery device.
Application example 2
The present application example provides a method for producing monofluoromethane by using the production apparatus system provided in application example 1, except that the mass of sodium fluoride is 23.3g (0.555 mol), and the mass of chloromethane is 56.05g (1.11 mol), which are the same as in application example 1.
Application example 3
This application example provides a method for producing monofluoromethane by using the production apparatus system provided in application example 1, except that the mass of 15-crown-5 is 2.04g (9.25 mmol), the mass of dimethyl carbonate is 500g (5.55 mol), the mass of sodium fluoride is 77.7g (1.85 mol) and the mass of chloromethane is 140.1g (2.78 mol), which is the same as in application example 1.
Application example 4
The application example provides a preparation method for preparing monofluoromethane by using the preparation device system provided in application example 1, wherein the preparation method comprises the following steps:
(a) Firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
(b) 9.78g (55.5 mmol) of 12-crown-4, 500g (5.55 mol) of dimethyl carbonate and 28.8g (1.11 mol) of lithium fluoride are dispersed in suspension under stirring at a stirring rate of 30rpm;
(c) Maintaining the working temperatures of the reflux condensing device and the crude gas cold trap, heating the reaction system to 50 ℃, ensuring stable escape of gas, reducing the escape of gas after 3 hours, and heating to 100 ℃ for reflux until the gas is fully escaped; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas can be obtained in a pure gas cold trap;
(d) The residual materials in the gas generating device are directly transferred into the byproduct conversion device without cooling, the stirring speed of 30rpm is maintained, the residual dimethyl carbonate is distilled off at normal pressure, and the residual dimethyl carbonate is collected in the dimethyl carbonate recovery device through the circulating condensing device; when the dimethyl carbonate is not distilled out any more, the crown ether is distilled out under reduced pressure and recycled to the crown ether recycling device; then adding the collected dimethyl carbonate into a byproduct conversion device, and dissolving and dispersing the rest methyl carbonate salt solid; after each discharge was closed, 224.2g (4.44 mol) of methyl chloride gas was introduced, nitrogen was supplemented and the temperature was raised to 170℃to a reaction system pressure of 6bar, whereby methyl carbonate salt was replaced with dimethyl carbonate;
(e) The reaction is carried out for 1h, the pressure in the system is obviously reduced, the temperature is reduced to the room temperature, the pressure is slowly released, and the escaped gas is collected in a raw material gas recovery trap through a circulating condensing device; the raw material gas recovery trap is also connected with a tail gas absorption device, and the tail gas is treated by the tail gas absorption device; then, completely distilling the dimethyl carbonate in the byproduct conversion device, and collecting the dimethyl carbonate in the dimethyl carbonate recovery device through a circulating condensing device; the residual white solid in the byproduct conversion device is removed and transferred to a waste recovery device.
Application example 5
The application example provides a preparation method for preparing monofluoromethane by using the preparation device system provided in application example 1, wherein the preparation method comprises the following steps:
(a) Firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
(b) 14.67g (55.5 mmol) of 18-crown-6, 500g (5.55 mol) of dimethyl carbonate and 64.5g (1.11 mol) of potassium fluoride are dispersed in suspension under stirring at a stirring rate of 150rpm;
(c) Maintaining the working temperatures of the reflux condensing device and the crude gas cold trap, heating the reaction system to 70 ℃, ensuring stable escape of gas, reducing the escape of gas after 1h, and heating to 100 ℃ for reflux until the gas is fully escaped; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas can be obtained in a pure gas cold trap;
(d) The residual materials in the gas generating device are directly transferred into the byproduct conversion device without cooling, the stirring speed of 150rpm is maintained, the residual dimethyl carbonate is distilled off at normal pressure, and the residual dimethyl carbonate is collected in the dimethyl carbonate recovery device through the circulating condensing device; when the dimethyl carbonate is not distilled out any more, the crown ether is distilled out under reduced pressure and recycled to the crown ether recycling device; then adding the collected dimethyl carbonate into a byproduct conversion device, and dissolving and dispersing the rest methyl carbonate salt solid; after each discharge was closed, 83.8g (1.66 mol) of methyl chloride gas was introduced, nitrogen was supplemented and the temperature was raised to 80℃to allow the reaction system pressure to 5bar, whereby methyl carbonate salt was replaced with dimethyl carbonate;
(e) The reaction is carried out for 4 hours, the pressure in the system is obviously reduced, the temperature is reduced to the room temperature, the pressure is slowly released, and the escaped gas is collected in a raw material gas recovery trap through a circulating condensing device; the raw material gas recovery trap is also connected with a tail gas absorption device, and the tail gas is treated by the tail gas absorption device; then, completely distilling the dimethyl carbonate in the byproduct conversion device, and collecting the dimethyl carbonate in the dimethyl carbonate recovery device through a circulating condensing device; the residual white solid in the byproduct conversion device is removed and transferred to a waste recovery device.
Application example 6
This application example provides a method for producing monofluoromethane by using the production apparatus system provided in application example 1, except that the mass of 12-crown-4 is 9.78g (55.5 mmol), the mass of dimethyl carbonate is 500g (5.55 mol), and the mass of sodium fluoride is 46.6g (1.11 mol), which is the same as in application example 4.
In the application example, the 12-crown ether-4 and sodium ions in sodium fluoride cannot be effectively complexed, so the preparation method provided in the application example almost has no CH 3 F, generating; in addition, the 12-crown ether-4 and sodium ions in sodium fluoride cannot be effectively complexed, so that the methyl carbonate salt is not recycled in the application example.
Application example 7
The present application example provided a method for producing monofluoromethane by using the production apparatus system provided in application example 1, except that the mass of 18-crown-6 was 14.67g (55.5 mmol), the mass of dimethyl carbonate was 500g (5.55 mol), the mass of sodium fluoride was 46.6g (1.11 mol), and the molar ratio of monochloromethane to sodium fluoride was 4:1, the same as in application example 5 was used.
Application example 8
The application example provides a preparation method for preparing monofluoromethane by using the preparation device system provided in application example 1, wherein the preparation method comprises the following steps:
(a) Firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
(b) 12.23g (55.5 mmol) of 15-crown-5, 500g (5.55 mol) of dimethyl carbonate and 28.8g (1.11 mol) of lithium fluoride are dispersed in suspension under stirring at a stirring rate of 30rpm;
(c) Maintaining the working temperatures of the reflux condensing device and the crude gas cold trap, heating the reaction system to 50 ℃, ensuring stable escape of gas, reducing the escape of gas after 3 hours, and heating to 100 ℃ for reflux until the gas is fully escaped; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas can be obtained in a pure gas cold trap;
(d) The residual materials in the gas generating device are directly transferred into the byproduct conversion device without cooling, the stirring speed of 30rpm is maintained, the residual dimethyl carbonate is distilled off at normal pressure, and the residual dimethyl carbonate is collected in the dimethyl carbonate recovery device through the circulating condensing device; when the dimethyl carbonate is not distilled out any more, the crown ether is distilled out under reduced pressure and recycled to the crown ether recycling device; then adding the collected dimethyl carbonate into a byproduct conversion device, and dissolving and dispersing the rest methyl carbonate salt solid; after each discharge was closed, 224.2g (4.44 mol) of methyl chloride gas was introduced, nitrogen was supplemented and the temperature was raised to 170℃to a reaction system pressure of 6bar, whereby methyl carbonate salt was replaced with dimethyl carbonate;
(e) The reaction is carried out for 1h, the pressure in the system is obviously reduced, the temperature is reduced to the room temperature, the pressure is slowly released, and the escaped gas is collected in a raw material gas recovery trap through a circulating condensing device; the raw material gas recovery trap is also connected with a tail gas absorption device, and the tail gas is treated by the tail gas absorption device; then, completely distilling the dimethyl carbonate in the byproduct conversion device, and collecting the dimethyl carbonate in the dimethyl carbonate recovery device through a circulating condensing device; the residual white solid in the byproduct conversion device is removed and transferred to a waste recovery device.
Application example 9
The application example provides a preparation method for preparing monofluoromethane by using the preparation device system provided in application example 1, wherein the preparation method comprises the following steps:
(a) Firstly, using a nitrogen cleaning unit to replace nitrogen in a container and a connecting pipeline of a preparation device system;
(b) 14.67g (55.5 mmol) of 18-crown-6, 500g (5.55 mol) of dimethyl carbonate and 28.8g (1.11 mol) of lithium fluoride are dispersed in suspension under stirring at a stirring rate of 30rpm;
(c) Maintaining the working temperatures of the reflux condensing device and the crude gas cold trap, heating the reaction system to 50 ℃, ensuring stable escape of gas, reducing the escape of gas after 3 hours, and heating to 100 ℃ for reflux until the gas is fully escaped; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas can be obtained in a pure gas cold trap;
(d) The residual materials in the gas generating device are directly transferred into the byproduct conversion device without cooling, the stirring speed of 30rpm is maintained, the residual dimethyl carbonate is distilled off at normal pressure, and the residual dimethyl carbonate is collected in the dimethyl carbonate recovery device through the circulating condensing device; when the dimethyl carbonate is not distilled out any more, the crown ether is distilled out under reduced pressure and recycled to the crown ether recycling device; then adding the collected dimethyl carbonate into a byproduct conversion device, and dissolving and dispersing the rest methyl carbonate salt solid; after each discharge was closed, 224.2g (4.44 mol) of methyl chloride gas was introduced, nitrogen was supplemented and the temperature was raised to 170℃to a reaction system pressure of 6bar, whereby methyl carbonate salt was replaced with dimethyl carbonate;
(e) The reaction is carried out for 1h, the pressure in the system is obviously reduced, the temperature is reduced to the room temperature, the pressure is slowly released, and the escaped gas is collected in a raw material gas recovery trap through a circulating condensing device; the raw material gas recovery trap is also connected with a tail gas absorption device, and the tail gas is treated by the tail gas absorption device; then, completely distilling the dimethyl carbonate in the byproduct conversion device, and collecting the dimethyl carbonate in the dimethyl carbonate recovery device through a circulating condensing device; the residual white solid in the byproduct conversion device is removed and transferred to a waste recovery device.
Application example 10
The present application example provides a method for preparing monofluoromethane by using the preparation apparatus system provided in application example 1, except that step (b) is modified to: 9.78g (55.5 mmol) of 12-crown-4, 500g (5.55 mol) of dimethyl carbonate and 64.5g (1.11 mol) of potassium fluoride are dispersed in suspension under stirring at a stirring rate of 150rpm;
the rest was the same as in application example 5.
In the application example, the 12-crown ether-4 cannot be effectively complexed with potassium ions in potassium fluoride, so the preparation method provided in the application example almost has no CH 3 F, generating; in addition, the 12-crown ether-4 cannot be effectively complexed with potassium ions in potassium fluoride, so that the methyl carbonate salt is not recycled in the application example.
Application example 11
The present application example provides a method for preparing monofluoromethane by using the preparation apparatus system provided in application example 1, except that step (b) is modified to: 12.23g (55.5 mmol) of 15-crown-5, 500g (5.55 mol) of dimethyl carbonate and 64.5g (1.11 mol) of potassium fluoride are dispersed in suspension under stirring at a stirring rate of 150rpm;
the rest was the same as in application example 5.
In the application example, the 15-crown ether-5 cannot be effectively complexed with potassium ions in potassium fluoride, so the preparation method provided in the application example almost has no CH 3 F, generating; in addition, because 15-crown ether-5 cannot be effectively complexed with potassium ions in potassium fluoride, the application example does not carry out recycling of methyl carbonate salt.
Application example 12
The present application example provides a method for preparing monofluoromethane by using the preparation apparatus system provided in application example 1, except that step (c) is modified to: maintaining the working temperature of the reflux condensing device and the crude gas cold trap, heating the reaction system to 30 ℃ for 3 hours, and then heating to 40 ℃ for 2 hours; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas can be obtained in a pure gas cold trap;
the rest was the same as in application example 1.
Application example 13
The present application example provides a method for producing monofluoromethane by using the production apparatus system provided in application example 1, except that (b) step is changed to: 245g (11.1 mmol) of 15-crown-5, 500g (5.55 mol) of dimethyl carbonate and 46.6g (1.11 mol) of sodium fluoride are dispersed in suspension under stirring at a stirring rate of 100rpm;
(c) The steps are changed as follows: maintaining the working temperature of the reflux condensing device and the crude gas cold trap, heating the reaction system to 90 ℃ for 3 hours, and then heating to 100 ℃ for 2 hours; the escaped gas is collected in a crude gas cold trap through a reflux condensing device, and is subjected to rectification treatment of a first rectifying tower, so that monofluoromethane gas can be obtained in a pure gas cold trap;
The rest was the same as in application example 1.
Comparative application example 1
The present comparative application example provides a method for producing monofluoromethane by using the production apparatus system provided in example 1, except that step (b) is modified to: 500g (5.55 mol) of dimethyl carbonate and 46.6g (1.11 mol) of sodium fluoride were dispersed in suspension with stirring at a stirring rate of 150rpm;
the rest was the same as in application example 5.
In the present application example, since crown ether is not used, the preparation method provided in the present comparative application example hardly contains CH 3 F, generating.
Recording CH in each application example and comparative application example 3 F quality of crude gas, gas phase Spectrometry (GC) purity, yield calculated based on alkali fluoride, crude gas CH 3 The purity after the rectification, the recovery rate of crown ether and the recovery rate of dimethyl carbonate are shown in Table 1.
For almost no CH 3 The result of the application example of F generation is denoted as "-".
TABLE 1
To sum up:
(1) The preparation method provided by the invention adopts a technical route for preparing the monofluoromethane by liquid phase reaction of the dimethyl carbonate and the alkali metal fluoride under the phase transfer catalysis of crown ether, wherein the dimethyl carbonate is a reactant and a solvent for dispersing the alkali metal fluoride, so that the use of an organic solvent is avoided;
(2) The invention adopts crown ether as phase transfer catalyst, which can make the reaction difficult to occur under the traditional condition proceed smoothly. For example, the reaction of dimethyl carbonate with alkali metal fluoride requires a large amount of organic solvent to aid in dispersing alkali metal fluoride salt due to F - Most of the counter alkali metal ions are present in pairs and therefore have insufficient reactivity, and the reaction is promoted by heating to 120 to 200 ℃ and even then the reaction rate is still low and the conversion is not high, the invention is realized by crown etherThe use of the (2) effectively overcomes the defects;
(3) The preparation device system provided by the invention corresponds to the preparation method, and has no harsh corrosion and high toxicity raw material introduction and intermediate product production in the whole production process of the monofluoromethane gas, so that the use of additional organic solvents is avoided, and the operation of the whole preparation device system is simple, thereby being suitable for industrial scale-up production.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that fall within the technical scope of the present invention disclosed herein are within the scope of the present invention.
Claims (4)
1. A process for the preparation of monofluoromethane, comprising the steps of:
(1) Mixing crown ether, dimethyl carbonate and alkali metal fluoride, and heating for reaction to obtain monofluoromethane gas and reacted feed liquid;
the temperature of the heating reaction is 40-100 ℃;
(2) Separating and recovering crown ether in the reacted feed liquid obtained in the step (1) to obtain separated feed liquid; then mixing and separating the feed liquid and excessive chloromethane, and reacting to obtain dimethyl carbonate;
the crown ether has holes with diameters larger than or equal to the diameters of alkali metal ions in the alkali metal fluoride, and the diameters of all holes in the crown ether are not required to be larger than or equal to the diameters of the alkali metal ions in the alkali metal fluoride;
the crown ether is any one of 12-crown ether-4, 15-crown ether-5 or 18-crown ether-6; the alkali metal fluoride is any one of lithium fluoride, sodium fluoride or potassium fluoride;
the 12-crown ether-4 is matched with lithium fluoride, the 15-crown ether-5 is matched with sodium fluoride, and the 18-crown ether-6 is matched with potassium fluoride;
the crown ether is 1% to 10% of the molar amount of alkali metal fluoride;
the molar ratio of alkali metal fluoride to dimethyl carbonate is from 1:5 to 1:10.
2. The method of claim 1, wherein the molar ratio of the methyl chloride of step (2) to the alkali metal fluoride of step (1) is from 2:1 to 4:1;
The temperature of the reaction in the step (2) is 80-170 ℃ and the time is 1-4 h.
3. A production apparatus system for the production method according to claim 1 or 2, characterized in that the production apparatus system comprises a gas generation unit, a rectification unit, and a nitrogen gas cleaning unit;
the gas generating unit comprises a gas generating device, a mixing device, a reflux condensing device and a crude gas cold trap; the discharge port of the mixing device is connected with the feed port of the gas generating device; the top exhaust port of the gas generating device is connected with the reflux condensing device; the discharge port of the reflux condensing device is connected with a crude gas cold trap;
the rectification unit comprises a first rectification tower, a heavy phase storage tank and a pure gas cold trap; the feed inlet of the first rectifying tower is connected with the discharge outlet of the crude gas cold trap; the bottom discharge pipeline of the first rectifying tower is connected with the heavy phase storage tank, and the top discharge pipeline of the first rectifying tower is connected with the pure gas cold trap;
the nitrogen pipeline of the nitrogen cleaning unit is connected with the connecting pipeline of the mixing device and the gas generating device;
the production plant system further comprises a byproduct conversion unit;
the byproduct conversion unit comprises a byproduct conversion device, a chloromethane supply device, a circulating condensing device, a raw material gas recovery trap, a dimethyl carbonate recovery device, a waste recovery device and a tail gas absorption device;
The discharge port of the methane chloride supply device and the gas generation device are respectively connected with the feed port of the byproduct conversion device; the bottom discharge port of the byproduct conversion device is connected with the waste recovery device; the top discharge port of the byproduct conversion device is connected with the circulating condensing device, and the exhaust port of the circulating condensing device is sequentially connected with the raw material gas recovery trap and the tail gas absorbing device; the bottom liquid outlet of the circulating condensing device is connected with the dimethyl carbonate recovery device; the bottom liquid outlet connected with the dimethyl carbonate recovery device is connected with the top liquid inlet of the byproduct conversion device;
the production plant system further comprises a reduced pressure distillation unit;
the reduced pressure distillation unit comprises a reduced pressure distillation device, a crown ether recovery device, a protection cold trap and a vacuum generation device;
the feed inlet of the reduced pressure distillation device is connected with a crown ether steam discharge pipeline of the byproduct conversion device; the bottom discharge port of the reduced pressure distillation device is connected with the crown ether recovery device, and the top discharge port of the reduced pressure distillation device is communicated with the vacuum generating device through a protection cold trap.
4. A production apparatus system according to claim 3, wherein stirring paddles are provided independently in each of the mixing device, the gas generating device, and the by-product converting device.
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