CN1100711A - Vapor phase chlorination of difluoromethyl methyl ether - Google Patents

Vapor phase chlorination of difluoromethyl methyl ether Download PDF

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CN1100711A
CN1100711A CN94104805A CN94104805A CN1100711A CN 1100711 A CN1100711 A CN 1100711A CN 94104805 A CN94104805 A CN 94104805A CN 94104805 A CN94104805 A CN 94104805A CN 1100711 A CN1100711 A CN 1100711A
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hoch
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hydrogen fluoride
chf
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CN1054115C (en
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G·J·奥尼尔
R·J·布尔卡
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Hampshire Chemical Corp
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Hampshire Chemical Corp
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
    • C07C41/01—Preparation of ethers
    • C07C41/18—Preparation of ethers by reactions not forming ether-oxygen bonds
    • C07C41/22—Preparation of ethers by reactions not forming ether-oxygen bonds by introduction of halogens; by substitution of halogen atoms by other halogen atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C43/00—Ethers; Compounds having groups, groups or groups
    • C07C43/02—Ethers
    • C07C43/03—Ethers having all ether-oxygen atoms bound to acyclic carbon atoms
    • C07C43/04—Saturated ethers
    • C07C43/12—Saturated ethers containing halogen

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  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The synthesis of fluorinated dimethyl ethers of the formula CF2HOCClxFyH(3-(x+y)) wherein x is 0, 1 or 2; y is 1, 2 or 3; and wherein (x+y) is 1, 2 or 3. The process involves chlorination of methyl difluoromethyl ether in the presence of oxygen to form a chlorinated reaction product of the formula CF2HOCH3-zClz wherein z is 1 or 2, and wherein the formation of CF2HOCCl3 is inhibited. The resulting compound(s) is then fluorinated with HF before or after separation, to give a fluorinated reaction product including the aforementioned fluorinated dimethyl ethers.

Description

Vapor phase chlorination of difluoromethyl methyl ether
The present invention relates generally to the fluorizated dme, especially as the synthetic methyl difluoro methyl ether of fluoridizing the raw material of dme.This class is fluoridized dme, comprises two (difluoromethyl) ether (CHF ZOCHF Z) can be used as the surrogate of CFC, especially as whipping agent, cooling agent etc.
Past is the chlorination by dme, separate then and carry out two (dichlormetbylethers) fluoridize preparation two (difluoromethyl) ether.This chlorinating step produces the mixture (some materials in this mixture for as distillation be unsettled) of complicated chlorination dme, therefrom can tell two (dichloromethyl) ether.Generate chloromethyl methyl ether and two (chloromethyl) ether by this reaction in addition, these compounds are carcinogenss.
Hine and Porter be in being published in Journal of the American Chemical Society 79, and 5493-6(1957) title on is the another kind of approach that has disclosed the synthesizing methyl difluoro methyl ether in the article of Methylene derivatives as intermediates in polar reaction VIII .Difluoromethylene in the Reaction of Chlorodifluoromethane with Sodium Methoxide.This article has been described a kind of reaction mechanism, wherein synthesizes required difluoromethyl methyl ether with intermittent reaction with fixed trimethylammonium-ortho-formiate by product ratio, carries out the continuous backflow of unreacted feed simultaneously.Yet this reaction not only generates a large amount of tri-methyl ortho formates, and product self also is decomposed into tri-methyl ortho formate, causes the productive rate of required difluoro methyl ether to be lower than favourable productive rate.
Its disclosure drawn the United States Patent (USP) 5,185,474 of making reference of the present invention disclose by use methyl difluoro methyl ether as starting raw material to avoid the generation of these carcinogenss and unstable compound.This methyl difluoro methyl ether chlorination generation is comprised at least a formula
CF 2HOCH 3-zCl zThe reaction mixture of compound.Z is 1,2 or 3 in the formula.This mixture can be fluoridized then.Perhaps telling earlier any chlorinated cpds from mixture also fluoridizes respectively.
Yet, at CF 2HOCH 3Chlorination process in be difficult to control the distribution of product.Although control Cl 2And CF 2HOCH 3Molar flow than producing the CF that holds a razor-thin majority 2HOCH 2Cl or CF 2HOCHCl 2, but still form a large amount of CF 2HOCCl 3If be CF by the required product of fluorizated subsequently 2HOCH 2Cl or CF 2HOCHCl 2, CF then 2HOCCl 3Formation can cause the obvious reduction of this method efficient.
Therefore an object of the present invention is to provide the preparation method of a kind of improved two (difluoromethyl) ether.
Another object of the present invention provides the preparation method of a kind of improved two (difluoromethyl) ether, in the method because the remarkable stability of various intermediate products can be carried out various required separation by distillation, and the danger that does not reduce productive rate and not have to explode.
A further object of the invention just provides a kind of preparation method of effective difluoromethyl methyl ether.
Preparation method by difluoromethyl methyl ether provided by the present invention has solved the problems of the prior art.Particularly, method of the present invention comprises preferential inhibition CF 2HOCCL 3Formation, and do not generate carcinogens as intermediate product.
In the prior art some of them be the complex mixture of carcinogenic unsettled chlorination ethers can be in the present invention by using methyl difluoro methyl ether be avoided as starting raw material.Obtain comprising at least a formula CF after this methyl difluoro methyl ether chlorination 2HOCH 3-zCl zThe reaction mixture of compound, z is 1,2 or 3 in the formula, this compound is easy to separate from chlorination reaction mixture.The chlorination of methyl difluoro methyl ether only forms three kinds of derivatives, i.e. z=1, z=2 and z=3 usually.Dichloromethyl difluoro methyl ether (z=2) is easy to separate from chlorination reaction mixture, then through or fluoridize generation two (difluoromethyl) ether after this separations.CF 2HOCCl 3(z=3) generation can be suppressed, and any product that has generated also can be separated from the chlorination reaction product and be fluoridized.On the other hand, it is as follows that chlorination reaction product self can be fluoridized (not separating in advance):
Figure 941048055_IMG1
Above-claimed cpd all can be used as cooling agent, and especially to be considered to be respectively the surrogate of R-11 and R-114 cooling agent for (I) methyl fluoride difluoro methyl ether and (II) two (difluoromethyl) ether.
Methyl difluoro methyl ether as the inventive method starting raw material is a kind of known compound, can the article institute reported method in they the above-mentioned Journal of being disclosed in of the American Chemical Society prepare with Hine and Porter.Particularly, use sodium methylate (NaOMe) and chloro methylene fluoride (CF 2HCl) prepared in reaction difluoromethyl methyl ether, this reaction is represented with following formula:
Briefly this method comprises the alcoholic solution that forms a sodium methylate and the chloro methylene fluoride is slowly blasted the methyl difluoro methyl ether that obtains in the reaction mixture as resistates in the reaction mixture.Some product is by unreacted CF 2HCl carries secretly away and can separate in distillation procedure.
Initial ether CHF 2OCH 3Also can be by using NaOH and CH earlier 3The OH reaction in fact makes CH 3ONa makes itself and CF then 2The HCl reaction.Yet at NaOH/CH 3Also formed water in the OH reaction, this water forms CHF subsequently 2OCH 3Reaction in reduce CHF 2OCH 3Productive rate.
Chlorination of the present invention and fluorination step are expressed as follows:
(z=1 in the formula, 2 or 3)
(z=1 in the formula, 2 or 3; Y=1,2 or 3; Y≤z)
The present inventor has been found that: by adding to the gas-phase reaction medium that oxygen source (preferably air) can suppress or or even eliminating the CF of z=3 in the above-mentioned reaction formula 2HOCH 3-zCl ZFormation we be surprised to find: the adding of oxygen preferentially suppresses CF 2HOCCl 3Formation rather than suppress three kinds of chlorizates with being equal to.Although the present inventor is not limited by any mechanism is theoretical, it is believed that this inhibition is because the result of oxygen and activatory chlorine molecule formation title complex causes, and is preferentially suppressed according to reaction kinetics three chlorine derivatives.Can use any oxygen source that required compound generates that do not damage, comprise the oxygenatedchemicals that discharges oxygen on the spot.
Oxygen should exist with the amount that can effectively produce required inhibition.With regard to air, preferred air add-on is about 1.5～5.5% of a total air flow.Those skilled in the art should be able to recognize that its consumption should be 1/5 of air consumption when using pure oxygen.Preferably, oxygen source adds reaction medium, as long as chlorine is mobile.
Have been found that by with CHF 2OCH 3Liquefaction also can make CHF with chlorine reaction in the visible light source irradiation 2OCH 3The appropriateness chlorination.Can use in addition as the other light sources of UV-light or heating, catalyzer or radical initiator with auxiliary this reaction.CHF 2OCH 3Chlorizate can before fluoridizing, be separated easily, obtain CF thereby perhaps also can not separate and reaction mixture fluoridized 2HOCCl 2F, CF 2HOCF 2Cl, CF 2HOCH 2F, CF 2HOCFHCl-, CF 2HOCF 2The mixture of H.All separation all can be used fractionation.
Chlorination CHF 2OCH 3Preferred method be to keep CHF 2OCH 3In gas phase and make itself and chlorine reaction, light source is provided for simultaneously this chlorination reaction, preferred visible or UV-light.In this chlorination reaction, also can use other reaction supplementary meanss to replace illumination in addition as catalyzer, heating or radical initiator.
In preferred fluorination process, chlorination reaction product and anhydrous hydrogen fluoride (HF) reaction, this reaction is represented with following formula:
Use hydrogen fluoride to carry out above-mentioned reaction and can obtain CF up to 78% 2HOCF 2Cl productive rate and a spot of CF 2HOCFCl 2This is the result who never reckons with, unless because under very high temperature, HF does not replace halogen such as chlorine usually, but by fluorizating agent such as SbCl 5-yF y, SbF for example 3Or SbF 3Cl 2Cyclic regeneration replace fluorochemical.Obviously difluoro-methoxy makes the chlorine activation on the alpha-carbon atom, thereby makes it be easy to react with HF.
Available in addition organic solvent preferably uses dipolar aprotonic solvent such as methyl-2-pyrrolidone dilution HF to fluoridize the cracking of raw material with minimizing, thereby obtains having only the higher yields of the required product that less by product produces.Other fluorine sources that are used for fluorination step comprise can form HF 2 -The metal fluoride of anionic salt, for example KHF 2, NaHF 2, LiHF 2, NH 4HF 2Deng, and HF and NaF, the KF pyridinium salt in appropriate solvent.
The fluorinated product of gained can be separated with distillation, perhaps uses United States Patent (USP) 4,025,567 or United States Patent (USP) 3,887,439 described methods separate, these two pieces of patents are all drawn makes reference of the present invention.
The present invention illustrates with following embodiment.
Embodiment 1
A) CF 2HOCH 3Preparation
The 25wt% methanol solution of sodium methylate (1533.1g) that will contain the 7.1mol sodium methylate is put into 4 liters of jacket layer autoclaves that temperature sensor, pressure warning unit and dipping tube are housed.This container is chilled to 0-5 ℃ also under agitation goes through 2.5 hours chloro methylene fluoride (318.2g, 3.70mol) adding.After the interpolation of gas is finished, this autoclave slowly is heated to about 60 ℃, discharges gaseous product simultaneously, it is entered in the collection cold-trap that is chilled to-70 ℃ of pacts by water-cooled condenser.
Collected behind all volatile matter at-20 ℃ unreacted CHF 2Cl shifts out, and with remaining CF 2HOCH 3Move in the metal bottle.(150.0g 1.83mol) shows with CF the difluoromethyl methyl ether that reclaims 2The productive rate of HCl meter is 49.4%.
B) CF 2HOCH 3Chlorination
Make gasiform chlorine and CF 2HOCH 3By being cooled to 0 ℃ separation condenser, air-flow is merged and it is fed in the side pipe arm of U-shaped reactor, become the UV irradiation with visible light.These reactor two side pipe arms all have chuck and use water-cooled.
At U type reactor bottom an outlet that links to each other with the product collection bottle is arranged.U type pipe opposite side outlet links to each other with the Dewar type condenser that is cooled to-50 ℃, and it links to each other with cold-trap and NaOH washer successively, and the former is in order to collect unreacted chlorine, and the latter is in order to remove HCl.This reaction is carried out under normal pressure usually, but also can use higher or lower pressure.Reactor temperature should too much not surpass 50 ℃, in order to avoid etch glass.
In actually operating, elder generation towards sweeping device, makes chlorine and CHF with nitrogen then 2OCH 3Enter reactor with certain speed,, promptly make CF for obtaining best effect 2HOCHCl 2, the throughput ratio of chlorine and ether should be maintained at about 2.5: 1.Can make the output of any product in three kinds of products preponderate by the ratio that changes gas flow rate.
2.3mol chlorine and 0.9mol CHF 2OCH 3Regain the 136.6g product by the back.The GC analysis revealed CF of product 2HOCH 2Cl accounts for 10.0%, CF 2HOCHCl 2Account for 62.4%, CF 2HOCCl 3Account for 22.2%.
C) fluoridize CHF with HF 2OCHCl 2
Anhydrous HF (30.0g) is preceding to contain 46.1%CF in stainless steel cylinder adding 2HOCHCl 2Chlorination CHF 2OCH 3(40.0g) in ice, cool off.This steel cylinder cuts out with valve and pressure warning unit, is placed in 60 ℃ of water-baths 3 hours then.This steel cylinder is communicated with a NaOH washer, and volatile products are collected in one and are cooled in-70 ℃ the cold-trap.The heavy 16.8g of the product that from this cold-trap, reclaims.The GC analysis revealed contains CF 2HOCF 2H71.8%, corresponding C F 2HOCF 2The H productive rate is 83.8%.
When carrying out mass production (as, 5 gallons), can obtain almost quantitative CF 2HOCF 2The H productive rate is (with CF 2HOCHCl 2Meter).
Embodiment 2
To contain 50%CF 2HOCCl 3Chlorination difluoro methyl ether mixture (25g) sample be positioned in the polyethylene bottle that the inlet pipe of carrier gas nitrogen and the escape pipe that links to each other with second polyethylene bottle be housed (filling NaOH solution (10%) in second polyethylene bottle), behind second polyethylene bottle be drying tube and in dry ice/MeOH the refrigerative cold-trap.
Excessive anhydrous hydrogen fluoride is added in the chlorating ether.Stir this mixture with magnetic stirrer then.Do not heat, temperature is maintained at about 20 ℃.Adding more hydrogen fluoride when needing all reacts until all organic raw material.The material of collecting from cold-trap must be 9.5g.
It contains 84.3%CF the GC analysis revealed of the product that reclaims 2HOCF 2Cl is according to the CF of chlorinated mixture 2OCCl 3Content meter productive rate is 78%.Also there is a small amount of CF in addition 2HOCFCl 2
Embodiment 3
This chloridizing unit comprises two sections vertical strap clamps cover Glass tubings, and it is long that this manages 4 chis, during internal diameter 2, is that the short U type pipe of 2 inch is continuous in the lower end with the internal diameter of strap clamp cover not.Draw a delivery pipe in order to collect the product that forms and from this device, to shift out product continuously from the lower-most point of U type device, product is collected in the collector.Settle three 150 watts of incandescent floodlights along every pipe.Make gas enter the higher-end of U type device one side pipe arm.Use the mass flow meter measurement flow through calibrating.The subcooling condenser in the second side pipe exit of U-shaped pipe makes unreacted E-152a and chlorine be back to the reaction zone that is illuminated.By product HCl and air enter water scrubber by condenser, are removed at this HCl.
The cooling jacket that 0-5 ℃ mixture cycles through device that is chilled to the first alcohol and water.
The coolant circulating that makes 0-5 ℃ in general operation is by cooling jacket, opens floodlight and dry ice is placed in the subcooling condenser.With in the chlorine gatherer, import difluoro methyl ether and air in required ratio then earlier.From receptor, shift out product and use saturated NaHCO through a spacer segment 3Solution washing is to remove HCl.Because reaction is carried out continuously, so can carry out the long arbitrarily time.Reaction stops air-flow when finishing, and product is disposed to the receptor from vertical reaction tubes.
The results are shown in the following table 1.What embodiment 6-29-1～6-29-7 showed is products distribution common when not adding air in air-flow.What embodiment 7-7-3 to 7-8-6 showed is the effect of adding air according to the present invention with the amount of successively decreasing.

Claims (11)

1, formula CF 2HOCCL xF yH 3-(x+y)The preparation method who fluoridizes dme, x is 0,1 or 2 in the formula, y is 1,2 or 3, and x+y and be 1,2 or 3, described method comprises:
Make described CHF 2OCH 3With chlorine chlorination under the condition that oxygen exists, generate and contain at least a formula CF 2HOCH 3-zCl zThe chlorinated mixture of compound, z is 1 or 2 in the formula, and suppresses CF 2HOCCl 3Formation and
With being selected from hydrogen fluoride, anhydrous hydrogen fluoride, HF 2 -The fluorine source of pyridinium salt of metal-salt, NaF, KF and HF, under the condition that does not have catalyzer to exist, fluoridize at least a described formula CF 2HOCH 3-zCl zCompound is to obtain containing at least a formula CF 2HOCH 3-zF yCl Z-yThe fluorizating mixture of compound.
2, according to the process of claim 1 wherein that described chlorinating step carries out in gas phase or liquid phase, chlorine is liquid or gas form.
3, according to the process of claim 1 wherein that described chlorinating step carries out in gas phase, chlorine is gas form.
4, according to the process of claim 1 wherein that hydrogen fluoride is selected from anhydrous hydrogen fluoride and the hydrogen fluoride in organic solvent.
5, according to the process of claim 1 wherein described at least a formula
CF 2HOCH 3-zCl zBe CF 2HOCHCl 2, described fluoridation product comprises CF 2HOCF 2H and CF 2HOCHFCl.
6, according to the process of claim 1 wherein described at least a formula
CF 2HOCH 3-zCl zCompound is CF 2HOCHCl 2, described at least a formula CF 2HOCCl xF yH 3-(x+y)Be CF 2HOCF 2H comprises in addition from described fluorizating mixture and to separate and reclaim described CF 2HOCF 2H
7, according to the process of claim 1 wherein that described chlorination should be enough to keep described CF 2HOCH 3For carrying out under the gasiform temperature and pressure.
8, also comprise and make CHF according to the process of claim 1 wherein 2Cl and a kind of alkali methylates react in solvent solution to generate described CHF 2OCH 3
9, according to the process of claim 1 wherein that air is described oxygen source.
10, formula CF 2HOCCl xF yH 3-(x+y)Fluoridize the preparation method of dme, x is 0,1 or 2 in the formula, and y is 1,2 or 3, x+y and be 1,2 or 3, wherein by making described CHF 2OCH 3Make CHF with chlorine reaction 2OCH 3Chlorination generates and contains at least a formula CF 2HOCH 3-zCl zThe chlorinated mixture of compound, z is 1 or 2 in the formula, and described at least a formula CF zHOCH 3-zCl zCompound is with being selected from hydrogen fluoride, anhydrous hydrogen fluoride, HF 2 -The fluorine of pyridinium salt of metal-salt, NaF, KF and HF come under the condition that does not have catalyzer to exist and fluoridize, obtain to contain at least a formula CF 2HOCH 3-ZF yCl Z-yThe fluorizating mixture of compound is wherein by carrying out described chlorinating step to suppress CF in the presence of oxygen 2HOCCl 3Formation.
11, according to the method for claim 10, wherein air is described oxygen source.
CN94104805A 1993-03-15 1994-03-14 Vapor phase chlorination of difluoromethyl methyl ether Expired - Fee Related CN1054115C (en)

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US025,009 1987-03-12
US08/025,009 US5278342A (en) 1992-03-25 1993-03-15 Vapor phase chlorination of difluoromethyl methyl ether
US025009 1993-03-15

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US10683252B2 (en) 2016-12-29 2020-06-16 Central Glass Company, Limited Production method for 1,2,2,2-tetrafluoroethyl difluoromethyl ether (desflurane)
JP6974718B2 (en) * 2017-01-13 2021-12-01 セントラル硝子株式会社 Method for producing 1,2,2,2-tetrafluoroethyldifluoromethyl ether (desflurane)
JP6886104B2 (en) 2016-12-29 2021-06-16 セントラル硝子株式会社 Method for producing halogenated α-fluoroethers
CN110139848B (en) * 2016-12-29 2022-04-12 中央硝子株式会社 Method for producing 1,2,2, 2-tetrafluoroethyl difluoromethyl ether (desflurane)

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JPH06298693A (en) 1994-10-25
MY110487A (en) 1998-08-29
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BR9401152A (en) 1994-11-01
TW252973B (en) 1995-08-01

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