JPH06263657A - Production of difluoromethane - Google Patents
Production of difluoromethaneInfo
- Publication number
- JPH06263657A JPH06263657A JP5095393A JP5095393A JPH06263657A JP H06263657 A JPH06263657 A JP H06263657A JP 5095393 A JP5095393 A JP 5095393A JP 5095393 A JP5095393 A JP 5095393A JP H06263657 A JPH06263657 A JP H06263657A
- Authority
- JP
- Japan
- Prior art keywords
- difluoromethane
- dichloromethane
- distillation column
- distillate
- reaction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
- C07C17/20—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms
- C07C17/202—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction
- C07C17/206—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction the other compound being HX
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ジクロロメタンとＨＦ
とを反応させて得たジフルオロメタン（以下、ＨＦＣ−
３２またはＣＨ2Ｆ2と記す）を簡単な装置を用いて効率
よく造ることができるＨＦＣ−３２の製造法に関する。FIELD OF THE INVENTION The present invention relates to dichloromethane and HF.
Difluoromethane obtained by reacting with (hereinafter, HFC-
32 or CH 2 F 2 ) is efficiently produced by using a simple apparatus.
【０００２】[0002]
【従来の技術】炭素数１〜４のハロゲン化炭化水素をＨ
Ｆによってフッ素化する方法には大別して気相法と液相
法がある。近年、塩素や臭素を分子中に含むフロン、ハ
ロンによるオゾン層破壊の問題がクローズアップされ、
それらの代替物質として分子内に水素を含むハロゲン化
炭化水素（ＨＣＦＣと略）や、塩素、臭素を分子内に含
まないフッ化炭化水素（ＨＦＣと略）が提案され、すで
に量産化されているものもある。2. Description of the Related Art Halogenated hydrocarbons having 1 to 4 carbon atoms are converted into H
The method of fluorinating with F is roughly classified into a gas phase method and a liquid phase method. In recent years, the problem of ozone layer depletion due to CFCs and halons that contain chlorine and bromine in the molecule has been highlighted.
Halogenated hydrocarbons containing hydrogen in the molecule (abbreviated as HCFC) and fluorohydrocarbons not containing chlorine and bromine in the molecule (abbreviated as HFC) have been proposed as alternative substances, and have already been mass-produced. There are also things.
【０００３】これらの内、ジクロロメタンとＨＦと反応
させるＨＦＣ−３２の製造において、気相法としてフッ
素化触媒は、Ｃr化合物(米国特許(ＵＳ)−２７４５８８
６，ＵＳ−３２３５６１２，ＵＳ−３７５５４７７，特
開昭５９−２２５１３１）等が提案され、一方、液相法
でハロゲン化アンチモンを触媒としてジクロロメタンを
フッ素化する手法も開示されている(ＵＳ−２００５７
１１)が、いずれも触媒に関する提案であり、実質的な
製造法に関するプロセス提案はなされていない。Among these, in the production of HFC-32, which is a reaction of dichloromethane and HF, a fluorination catalyst is a Cr compound (US Pat. No. 274588) as a gas phase method.
6, US-3235612, US-3755477, JP-A-59-225131) and the like are proposed, and on the other hand, a method of fluorinating dichloromethane by a liquid phase method using antimony halide as a catalyst is also disclosed (US-20057).
11) are all proposals regarding catalysts, and no process proposals regarding substantial manufacturing methods have been made.
【０００４】[0004]
【発明が解決しようとする課題】これまでＨＦＣ−３２
の実質的な製造法に関するプロセス提案がなかった理由
として、 フッ素化反応の反応・精製系では系内は酸、有機ハロ
ゲン化物が混在し、理想系とかけ離れ、複雑な挙動を示
す場合が多く、このため、目的成分と他の成分を効率よ
く分離するために、正確な気液平衡データを採取し、最
適なプロセスを構築する必要がある。[Problems to be Solved by the Invention] HFC-32
The reason why there was no process proposal regarding the substantial manufacturing method of fluorination reaction is that in the reaction / refining system of the fluorination reaction, acid and organic halides are mixed in the system, which is far from the ideal system and often shows complicated behavior, Therefore, in order to efficiently separate the target component and other components, it is necessary to collect accurate vapor-liquid equilibrium data and construct an optimum process.
【０００５】ＨＦＣ−３２は主として半導体製造プロ
セスにおけるエッチャントとして使用される程度で大量
に必要とされる物質ではなかった。しかし、最近になっ
てオゾン層を破壊する恐れのないことから、現在、冷蔵
庫やルームエアコン等の冷媒として大量に使用されてい
るＨＣＦＣ−２２(ＣＨＣｌＦ2）の代替冷媒として脚光
をあび、効率よく大量に製造するプロセスが必要とされ
ている。 本発明が解決しようとする課題は、上記事情に鑑み、Ｈ
ＦＣ−３２の実質的な製造法に関するプロセス提案であ
り、簡単な装置を用いて効率よく、ＨＦＣ−３２を大量
に製造する方法を提供するものである。HFC-32 was not a substance required in large quantities to be used mainly as an etchant in the semiconductor manufacturing process. However, since there is no fear of depleting the ozone layer recently, it has been spotlighted as an alternative refrigerant to HCFC-22 (CHClF 2 ) which is currently used in large quantities as a refrigerant for refrigerators, room air conditioners, etc., and efficiently. A high volume manufacturing process is needed. In view of the above circumstances, the problem to be solved by the present invention is H
It is a process proposal regarding a substantial production method of FC-32, and provides a method for producing HFC-32 in a large amount efficiently using a simple apparatus.
【０００６】[0006]
【課題を解決するための手段】本発明はジクロロメタン
とＨＦとを反応させるジフルオロメタンの製造法におい
て、ジクロロメタンとＨＦとを反応させて生成する生成
物を第一蒸留塔に導いて、ジフルオロメタンとＨＣｌを
主成分とする留出分、ジクロロメタン、クロロフルオロ
メタンおよびＨＦを主成分とするボトム液に分け、上記
留出分を第二蒸留塔に導いてＨＣｌを留出せしめ、ボト
ムからはジフルオロメタンを主成分とする液を抜き出
し、これを別に設けられた精製工程に導いてジフルオロ
メタンを回収し、第一蒸留塔ボトム液はジクロロメタ
ン、ＨＦを添加して成分割合および量を調整して反応器
に供給して反応せしめるジフルオロメタンの製造法であ
る。Means for Solving the Problems The present invention relates to a method for producing difluoromethane in which dichloromethane and HF are reacted with each other. The product produced by reacting dichloromethane and HF is introduced into a first distillation column to produce difluoromethane. It is divided into a distillate containing HCl as a main component, a bottom liquid containing dichloromethane, chlorofluoromethane and HF as a main component, and the distillate is introduced into a second distillation column to distill off HCl. A liquid containing as a main component is extracted, and this is introduced into a separately provided purification step to recover difluoromethane, and the first distillation column bottom liquid is added with dichloromethane and HF to adjust the proportion and amount of the components, and the reactor It is a method for producing difluoromethane which is fed to and reacted.
【０００７】一般にＨＦＣ−３２の製造法は、（１）式
に示すように ＣＨ2Ｃｌ2＋２ＨＦ→ＣＨ2Ｆ2＋２ＨＣｌ ……………………（１）式 ジクロロメタンとＨＦを反応させることによって行なわ
れる。Generally, the method of producing HFC-32 is as follows: CH 2 Cl 2 + 2HF → CH 2 F 2 + 2HCl (1) Formula (1) Dichloromethane and HF are reacted. Done by.
【０００８】この反応は、例えばアルミナ・クロミナ等
の触媒の存在下、ジクロロメタンに対するＨＦのモル
比：２〜１０、反応温度：１５０〜４００℃、反応圧
力：大気圧〜２０kg/cm2(ゲージ圧)、ＳＶ：１００〜５
０００Hr-1の範囲で行なわれる。In this reaction, for example, in the presence of a catalyst such as alumina / chromina, the molar ratio of HF to dichloromethane: 2 to 10, reaction temperature: 150 to 400 ° C., reaction pressure: atmospheric pressure to 20 kg / cm 2 (gauge pressure) ), SV: 100-5
It is performed in the range of 000 Hr -1 .
【０００９】反応生成物は、目的物であるＨＦＣ−３
２、中間体であるクロロフルオロメタン(ＣＨ2Ｃｌ
Ｆ）、未反応原料のジクロロメタン(ＣＨ2Ｃｌ2)、副生
ＨＣｌおよび未反応原料のＨＦの他に、微量不純物とし
て、ＣＨＦ3，ＣＨ3Ｆ，ＣＨ3ＣＦ3，ＣＦ3ＣＨＦ2，Ｃ
Ｈ3Ｃl等が生成し、反応、精製系では系内は酸、有機ハ
ロゲン化物が混在し、複雑な挙動を示す。The reaction product is the target product, HFC-3.
2, an intermediate chlorofluoromethane (CH 2 Cl
F), dichloromethane (CH 2 Cl 2 ) as an unreacted raw material, HCl as a by-product and HF as an unreacted raw material, and as trace impurities CHF 3 , CH 3 F, CH 3 CF 3 , CF 3 CHF 2 , C
H 3 Cl and the like are produced, and in the reaction and purification system, an acid and an organic halide are mixed in the system, and a complicated behavior is exhibited.
【００１０】このため、目的成分と他の成分を効率よく
分離するためには、正確な気液平衡データを採取し、最
適なプロセスを構築しなければならない。これら対象と
する系は、気相会合や共沸を起こすので解析が複雑な上
に、ＨＣｌのような沸点が極めて低い成分からジクロロ
メタンのように沸点が高い成分まで存在し、通常法では
測定が困難である。これらの系を正確に測定する方法と
して、全圧法（全圧法は各成分の正確な仕込みのもと
に、温度、圧力を測り、熱力学的理論に基づいて、気液
平衡関係を求める方法）を用いて気液平衡データを採取
した。Therefore, in order to efficiently separate the target component from other components, it is necessary to collect accurate gas-liquid equilibrium data and construct an optimum process. These target systems are complicated to analyze because they cause vapor phase association and azeotropy, and in addition, there are components with extremely low boiling points such as HCl to components with high boiling points such as dichloromethane. Have difficulty. As a method for accurately measuring these systems, the total pressure method (the total pressure method is a method of measuring the temperature and pressure under the accurate preparation of each component and obtaining the gas-liquid equilibrium relationship based on thermodynamic theory). Was used to collect the vapor-liquid equilibrium data.
【００１１】例えば、ＣＨ2ＣlＦ／ＨＦ系は最低共沸混
合物を形成し、１kg/cm2Ｇの圧力下では共沸温度３.７
℃、共沸温度における成分割合はＣＨ2ＣｌＦ６３mol
%、ＨＦ３７mol%である。また、５kg/cm2Ｇの圧力下で
は共沸温度３７℃、共沸温度における成分割合はＣＨ2
ＣｌＦ７０mol%、ＨＦ３０mol%である。For example, the CH 2 ClF / HF system forms the lowest azeotrope, and under the pressure of 1 kg / cm 2 G the azeotropic temperature is 3.7.
CH 2 ClF 63 mol at ℃ and azeotropic temperature
%, HF 37 mol%. Also, under the pressure of 5 kg / cm 2 G, the azeotropic temperature is 37 ° C., and the component ratio at the azeotropic temperature is CH 2
It is 70 mol% of ClF and 30 mol% of HF.
【００１２】また、ＣＨ2Ｃｌ2／ＨＦ系も同様に最低共
沸混合物を形成し、１kg/cm2Ｇの圧力下では共沸温度３
９．６℃、共沸温度における成分割合はＣＨ2Ｃｌ2６mo
l%、ＨＦ９４mol%である。５kg/cm2Ｇの圧力下では共沸
温度６９．５℃、共沸温度における成分割合はＣＨ2Ｃ
ｌ2１６mol%、ＨＦ８４mol%である。一方、ＣＨ2Ｆ2／
ＨＦ系は共沸混合物を形成しないことを見出した。The CH 2 Cl 2 / HF system likewise forms a minimum azeotropic mixture, and the azeotropic temperature is 3 at a pressure of 1 kg / cm 2 G.
The component ratio at 9.6 ° C and azeotropic temperature is CH 2 Cl 2 6mo.
1% and HF 94 mol%. Under the pressure of 5 kg / cm 2 G, the azeotropic temperature is 69.5 ° C, and the component ratio at the azeotropic temperature is CH 2 C.
L 2 16 mol% and HF 84 mol%. On the other hand, CH 2 F 2 /
It has been found that the HF system does not form an azeotrope.
【００１３】これらの気液平衡測定結果に基づき、第一
蒸留塔でＨＦと共沸混合物を形成しないＨＣｌとＨＦＣ
−３２を塔頂より留出させ、第二蒸留塔へ導き、ＨＣｌ
とＨＦＣ−３２は共沸関係を有しないので簡単に塔頂よ
りＨＣｌ、塔底よりＨＦＣ−３２を分離することができ
る。Based on these gas-liquid equilibrium measurement results, HCl and HFC which do not form an azeotrope with HF in the first distillation column
-32 is distilled from the top of the column, introduced to the second distillation column, and HCl is added.
Since HFC-32 and HFC-32 do not have an azeotropic relationship, HCl can be easily separated from the top of the column and HFC-32 can be separated from the bottom of the column.
【００１４】第一蒸留塔のボトム液は、共沸関係にある
ＣＨ2ＣlＦ，ＨＦおよびＣＨ2Ｃｌ2で、新たにＣＨ2Ｃ
ｌ2およびＨＦを添加して、成分割合および量を調整し
て反応器に供給して反応させる効率的なＨＦＣ−３２の
製造法である。[0014] bottoms liquid of the first distillation column, in CH 2 ClF, HF and CH 2 Cl 2 in the azeotropic relationship, newly CH 2 C
It is an efficient method for producing HFC-32 in which 1 2 and HF are added to adjust the component proportions and amounts and the mixture is supplied to the reactor for reaction.
【００１５】図１は本発明に係るＨＦＣ−３２の製造法
のフローの実施例を示す図で、符号１は反応器である。
好ましい反応条件の目安としては、例えば、反応圧力：
２kg/cm2、反応温度：２２０℃、ＨＦ／ジクロロメタン
モル比：６である。反応生成物は１４として、例えばポ
ンプで昇圧し第一蒸留塔２に導入される。第一蒸留塔２
は、例えば操作圧力５kg/cm2Ｇにおいて留出分１５、ボ
トム液１６に分けられる。上記留出分１５はＨＣｌ，Ｈ
ＦＣ−３２が主成分で第二蒸留塔３へ導かれる。FIG. 1 is a diagram showing an embodiment of the flow of the method for producing HFC-32 according to the present invention, in which reference numeral 1 is a reactor.
Examples of preferable reaction conditions include, for example, reaction pressure:
2 kg / cm 2 , reaction temperature: 220 ° C., HF / dichloromethane molar ratio: 6. The reaction product as 14 is introduced into the first distillation column 2 after increasing the pressure with a pump, for example. First distillation column 2
Is divided into a distillate 15 and a bottom liquid 16 at an operating pressure of 5 kg / cm 2 G, for example. The distillate 15 is HCl, H
FC-32 is the main component and is guided to the second distillation column 3.
【００１６】第二蒸留塔３では、留出分１７とボトム液
１８とに分けられる。この第二蒸留塔３の留出分１７は
ＨＣｌが主体で精製され、他の用途に使用される。ボト
ム液１８は目的物であるＨＦＣ−３２が主体で、このボ
トム液は、別に設けられた精製工程４に導かれ、ＨＦＣ
−３２が回収される。その際、含有される他の成分は、
反応器へリサイクルしてもよい。In the second distillation column 3, a distillate 17 and a bottom liquid 18 are separated. The distillate 17 of the second distillation column 3 is mainly purified by HCl and used for other purposes. The bottom liquid 18 is mainly the target product HFC-32, and this bottom liquid is guided to the purification step 4 provided separately, and the HFC-32 is used.
-32 is recovered. At that time, the other components contained are
It may be recycled to the reactor.
【００１７】第一蒸留塔２のボトム液１６は、ジクロロ
メタン、クロロフルオロメタンおよびＨＦが主体であ
り、新しいジクロロメタンおよびＨＦが添加され、その
成分割合および量が調整された後、反応器の原料１３と
して使用される。The bottom liquid 16 of the first distillation column 2 is mainly composed of dichloromethane, chlorofluoromethane and HF. After fresh dichloromethane and HF are added and the proportion and amount of the components are adjusted, the raw material 13 of the reactor is prepared. Used as.
【００１８】実施例の装置は、上記の構成となっている
ので、反応器の生成物を第一蒸留塔２、第二蒸留塔３の
２基の蒸留塔によって、目的生成物であるＨＦＣ−３
２、副生ＨＣｌ、反応原料の調整に使用できるＨＦ、ジ
クロロメタンおよび中間体のクロロフルオロメタンに分
離され、これらと補給原料となる新しいＨＦおよびジク
ロロメタンを組み合せて、反応および蒸留分離が行なわ
れるので、少ない装置によって効率よくＨＦＣ−３２を
製造することができる。Since the apparatus of the embodiment has the above-mentioned constitution, the product of the reactor is subjected to two distillation columns, the first distillation column 2 and the second distillation column 3, to obtain the target product, HFC-. Three
2. By-produced HCl, HF that can be used to prepare reaction raw materials, dichloromethane, and chlorofluoromethane as an intermediate are separated, and these are combined with new HF and dichloromethane that are supplementary materials to carry out reaction and distillation separation. HFC-32 can be efficiently produced with a small number of devices.
【００１９】[0019]
【実施例】次に実施例を示して、本発明を具体的に説明
する。 実施例１ 本発明に係る図１のフローを例として各部における成分
の重量％、および反応生成物１４の量を１００とした場
合の各部の流量を表１に例示する。EXAMPLES Next, the present invention will be specifically described with reference to examples. Example 1 Table 1 exemplifies the flow rate of each part in the case where the weight% of the components in each part and the amount of the reaction product 14 are 100, taking the flow of FIG. 1 according to the present invention as an example.
【００２０】[0020]
【表１】 [Table 1]
【００２１】表１より明らかなように、２本の蒸留塔に
よって反応生成物を分離し、これらと補給ＨＦおよびジ
クロロメタンを組み合せて、反応器原料が調整されると
ともに副生ＨＣｌが回収され、目的とする製品ＨＦＣ−
３２が濃縮される。As is apparent from Table 1, the reaction products are separated by two distillation columns, and these are combined with make-up HF and dichloromethane to prepare the reactor raw material and recover the by-product HCl. HFC-
32 is concentrated.
【００２２】[0022]
【発明の効果】以上説明したように、本発明に係るＨＦ
Ｃ−３２の製造法は、２本の蒸留塔によって反応生成物
を分離し、これらと補給ＨＦおよびジクロロメタンを組
み合せて、反応器原料を調整するとともに、副生ＨＣｌ
が回収され、目的とするＨＦＣ−３２が効率よく製造さ
れる。As described above, the HF according to the present invention
In the method for producing C-32, the reaction products are separated by two distillation columns, and these are combined with make-up HF and dichloromethane to prepare a reactor raw material and to produce a by-product HCl.
Is recovered, and the target HFC-32 is efficiently produced.
【図１】本発明のＨＦＣ−３２の製造法の実施例を示す
フロー図である。FIG. 1 is a flow chart showing an example of a method for producing HFC-32 of the present invention.
１ 反応器 ２ 第一蒸留塔 ３ 第二蒸留塔 ４ 精製工程 １１ 系内に導入されるジクロロメタン １２ 系内に導入されるＨＦ １３ 反応器に導入される原料 １４ 反応生成物 １５ 第一蒸留塔留出分 １６ 第一蒸留塔ボトム液 １７ 第二蒸留塔留出分 １８ 第二蒸留塔ボトム液 DESCRIPTION OF SYMBOLS 1 Reactor 2 First distillation column 3 Second distillation column 4 Purification step 11 Dichloromethane introduced into system 12 HF introduced into system 13 Raw material introduced into reactor 14 Reaction product 15 First distillation column distillation Fraction 16 First distilling column bottom liquid 17 Second distilling column distillate 18 Second distilling column bottom liquid
Claims (1)
フルオロメタンの製造法において、ジクロロメタンとＨ
Ｆとを反応させて生成する生成物を第一蒸留塔に導い
て、ジフルオロメタンとＨＣｌを主成分とする留出分、
ジクロロメタン、クロロフルオロメタンおよびＨＦを主
成分とするボトム液に分け、上記留出分を第二蒸留塔に
導いてＨＣｌを留出せしめ、ボトムからはジフルオロメ
タンを主成分とする液を抜き出し、これを別に設けられ
た精製工程に導いてジフルオロメタンを回収し、前記第
一蒸留塔ボトム液はジクロロメタン、ＨＦを添加して成
分割合および量を調整して反応器に供給して反応せしめ
るジフルオロメタンの製造法。1. A method for producing difluoromethane by reacting dichloromethane and HF, which comprises:
The product produced by the reaction with F is introduced into the first distillation column, and the distillate containing difluoromethane and HCl as the main components,
Divide into a bottom liquid containing dichloromethane, chlorofluoromethane and HF as main components, guide the above distillate to a second distillation column to distill off HCl, and withdraw a liquid containing difluoromethane as a main component from the bottom. To a purification step separately provided to recover difluoromethane, and the first distillation column bottom liquid is added with dichloromethane and HF to adjust the proportion and amount of the components, and the difluoromethane of the difluoromethane to be reacted is supplied. Manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5095393A JPH06263657A (en) | 1993-03-11 | 1993-03-11 | Production of difluoromethane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5095393A JPH06263657A (en) | 1993-03-11 | 1993-03-11 | Production of difluoromethane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06263657A true JPH06263657A (en) | 1994-09-20 |
Family
ID=12873197
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5095393A Pending JPH06263657A (en) | 1993-03-11 | 1993-03-11 | Production of difluoromethane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06263657A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997011043A1 (en) * | 1995-09-20 | 1997-03-27 | Alliedsignal Inc. | Process for the production of difluoromethane |
| FR2748022A1 (en) * | 1996-04-29 | 1997-10-31 | Atochem Elf Sa | PROCESS FOR PRODUCING DIFLUOROMETHANE |
| US6242659B1 (en) | 1995-06-29 | 2001-06-05 | Elf Atochem, S.A. | Process for the manufacture of difluoromethane |
| EP1542949A1 (en) * | 2002-07-10 | 2005-06-22 | Srf Limited | A process for the production of difluoromethane |
| JP4869230B2 (en) * | 2004-08-04 | 2012-02-08 | ハネウェル・インターナショナル・インコーポレーテッド | An azeotrope-like composition of difluoromethane |
| CN108273279A (en) * | 2017-11-28 | 2018-07-13 | 聊城市鲁西化工工程设计有限责任公司 | A kind of efficient HCl separation method |
-
1993
- 1993-03-11 JP JP5095393A patent/JPH06263657A/en active Pending
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6639115B2 (en) | 1995-06-29 | 2003-10-28 | Atofina | Process for the manufacture of difluoromethane |
| US6242659B1 (en) | 1995-06-29 | 2001-06-05 | Elf Atochem, S.A. | Process for the manufacture of difluoromethane |
| WO1997011043A1 (en) * | 1995-09-20 | 1997-03-27 | Alliedsignal Inc. | Process for the production of difluoromethane |
| US6844474B1 (en) | 1995-09-20 | 2005-01-18 | Allied Signal Inc. | Process for the production of difluoromethane |
| US5763708A (en) * | 1995-09-20 | 1998-06-09 | Allied Signal Inc. | Process for the production of difluoromethane |
| US6365580B1 (en) | 1995-09-20 | 2002-04-02 | Alliedsignal Inc. | Process for the production of difluoromethane |
| US6635790B1 (en) | 1996-04-29 | 2003-10-21 | Atofina | Process for the manufacture of defluoromethane |
| EP0805136A1 (en) * | 1996-04-29 | 1997-11-05 | Elf Atochem S.A. | Process for the preparation of difluoromethane |
| FR2748022A1 (en) * | 1996-04-29 | 1997-10-31 | Atochem Elf Sa | PROCESS FOR PRODUCING DIFLUOROMETHANE |
| EP1542949A1 (en) * | 2002-07-10 | 2005-06-22 | Srf Limited | A process for the production of difluoromethane |
| EP1542949A4 (en) * | 2002-07-10 | 2006-05-17 | Srf Ltd | A process for the production of difluoromethane |
| JP4869230B2 (en) * | 2004-08-04 | 2012-02-08 | ハネウェル・インターナショナル・インコーポレーテッド | An azeotrope-like composition of difluoromethane |
| CN108273279A (en) * | 2017-11-28 | 2018-07-13 | 聊城市鲁西化工工程设计有限责任公司 | A kind of efficient HCl separation method |
| CN108273279B (en) * | 2017-11-28 | 2021-04-02 | 聊城市鲁西化工工程设计有限责任公司 | High-efficiency low-consumption hydrogen chloride separation method |
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