• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A process for the preparation of hexafluoropropene by thermal cleavage of chlorotetrafluoroethane and/or chlorohexafluoropropane or a mixture of chlorotetrafluoroethane and perfluorocyclobutane at 600 to 1000 DEG C and at a pressure of 1 to 1000 kPa is described. The thermal cleavage is carried out in the presence of at least 0.05 mol of tetrafluoroethene relative to 1 mol of chlorotetrafluoroethane and/or chlorohexafluoropropane or of a mixture of chlorotetrafluoroethane and perfluorocyclobutane employed. By this means, hexafluoropropene is obtained in good selectivity with improved space-time yield and with a low additional outlay in terms of apparatus.
    公开号:SU1720485A3
    申请号:SU894613648
    申请日:1989-03-13
    公开日:1992-03-15
    发明作者:Фройденрайх Райнхольд；Мильке Ингольф；Реттенбек Карл；Шеттле Томас
    申请人:Хехст Аг (Фирма)；
    IPC主号:
    专利说明:

    The invention relates to a process for the preparation of hexafluoropropylene.
    Hexafluoropropylene is used as a comonomer for the technical preparation of tetrafluoroethylene based polymers. Therefore, the challenge is to improve the expensive methods of producing hexafluoropropylene.
    Known to obtain hexafluoropropylene heat treatment of many fluorinated hydrocarbons, in particular tetrafluoroethylene at 600-1200 ° C. At 655 ° С under normal pressure, hexafluoropropylene is obtained with a yield of 42%, and at 750 ° С the yield of hexafluoropropylene is significant.
    it tends to increase and predominantly form octafluorobutene.
    Hexaforpropylene is obtained by pyrolysis of tetrafluoroethylene and / or octafluorocyclobutane in the presence of 50–95 mol% water vapor under adiabatic conditions at 700–900 ° C, while the pyrolysis temperature is controlled by a mixture of reagents with superheated water vapor. This method gives good yields on hexafluoroethylene, but requires expensive distillation separation with respect to equipment and energy, which is formed during the pyrolysis of chlorodifluoromethane to produce tetrafluoroethylene blend chlorine
    GO
    about
    coke
    with
    tetrafluoroethane and octafluorocyclobutane, as well as the expensive addition of superheated water vapor, which, according to the proposed method, is possible but not necessary.
    Pyrolysis of chlorotetrafluoroethylene at 700-850 ° C is known, with 1,1-difluoroethylene and hexafluoropropylene being the main products.
    There is also known a method for producing hexafluoropropylene by pyrolysis of chlorodifluoromethane and 2-chloro-1,1,1,2-tetrafluoroethylene in the ratio of 1: 1-10: 1 at 500-1000 ° C. Hexafluoropropylene is obtained with a selectivity of 42.0-79.0%. However, if instead of 2-chloro-1.1,1,2-tetrafluoroethane, 1-chloro-1,1,2,2-tetrafluoroethane is used, which is mainly formed during technical pyrolysis. chlorofluoromethane to tetrafluoroethylene as a by-product, difficulties arise and poor selectivity to hexafluoropropylene is observed. This complicates the process.
    The purpose of the invention is to simplify the process technology.
    According to the invention, hexafluoropropylene is obtained by thermally splitting a mixture of halogenated hydrocarbons containing 2 or-1,1.1,2-tetrafluoroethane, in particular, containing 54-95% by weight of 1-chloro-1,1,2,2-tetrafluoroethane and 5 -46 wt.% 2-chloro-1,1,1,2-tetrafluoroethane with chlorhexafluoropropane or this mixture of chlorotetrafluoroethanes with perfluorocyclobutane, and the process is carried out at 700–900 ° C and a pressure of 109–300 kPa, in the presence of 0.4 - 9.8 mol of tetrafluoroethylene per 1 mol of the initial mixture of halogenated hydrocarbons with a contact time of 0.07-1.2 s.
    Preferably, prior to thermal cleavage, water vapor is added in an amount of 0.3-1.2.5 mol per 1 mol of the initial gas mixture of halogenated hydrocarbons and tetrafluoroethylene.
    Here, 1-chloro-1,1,2,2-tetrafluoroethane and 1-chloro-1,1,2,2,3,3-hexafluoropropane are mainly formed as by-products in the technical preparation of tetrafluoroethylene by thermal decomposition of chlorofluoromethane. Chlorotetrafluoroethanes and perfluorocyclobutane are also used, in particular, azeotropic mixture of chlorotetrafluoroethanes and perfluorocyclobutane. formed as a by-product in the technical preparation of tetrafluoroethylene by thermal decomposition of chlorodifluoromethane.
    The reactor in which thermal decomposition takes place may have a different
    construction For example, it may be a simple tube that is heated externally, or a reactor, in which the gaseous substances to be thermally decomposed.
    Fluorinated compounds are generally brought to a temperature at which thermal decomposition takes place using a heated inert gas. As the material of the walls that are in contact with
    0 by gases during thermal decomposition,
    for example, nickel are suitable,
    containing a lot of nickel steel, graphite,
    platinum or similar rare metals.
    After thermal decomposition, it is advisable to quickly cool the gas mixture by spraying with water, rinse it again with water, and then treat it with caustic alkali, for example, sodium hydroxide, then dry, for example, with concentrated sulfuric acid and fractionally distill. Hexafluoropropylene is obtained as the main reaction product, with good selectivity. The amounts of unreacted tetra-5-thoretilene, and also in the particular case of chloro-tetrafluoroethane, chloro-hexafluoro-propane or perfluorocyclobutane, are recycled. Unwanted adverse reactions destroy.
    Thus, the proposed method allows to obtain hexafluoropropylene by the interaction of chlorotetrafluoroethane and / or chlorohexafluoropropane, in particular, which are mainly formed as a result of obtaining
    tetrafgorogilen compounds 1 chloro-1,1,2,2-tetrafluoroethane and 1-chloro-1,1,2,2,3,3-hexafluoropropane, with good selectivity, with significantly improved time and volume output without an increase in temperature decomposition. In addition, the new method makes it possible to convert chlorotetrafluoroethylene and perfluorocyclobutane into hexafluoropropylene, in particular, forming azeotropic mixtures of chlorotetrafluoroethane as a by-product in the technical preparation of tetrafluoroethylene and a considerable improvement in volume and time.
    0 output without increasing the decomposition temperature. The new method requires only minor hardware costs in comparison with the known thermal decomposition of chlorotetrafluoroethane or perfluorocyclobutane without
    5 tetrafluoroethylene additives.
    Comparative experiments A and E, as well as examples 1-6.
    Thermally decomposed chlorotetrafluoroethane, chlorohexafluoropropane, mixtures of chlorotetrafluoroethane and
    perfluorocyclobutane, as well as chlorodifluoromethane, are taken in liquid form into individual steel bottles, each substance is evaporated in a vaporizer heated with a reduced pressure, and introduced through a heated rotameter into a heated mixing chamber. The exact amounts of the substance are determined by weighing the steel bottles. Tetrafluoroethylene is introduced into the mixing chamber as a gas through a flow meter. Samples are taken from the mixing chamber and examined by gas chromatography. Steam is supplied to the mixing chamber through a pipeline equipped with a special heating. The amount of water vapor can be precisely controlled with the help of a pulsed metered pump (type MDR-600 from Labomatic / Sinsheili).
    From the mixing chamber, a gas mixture containing water vapor enters the reactor, consisting of a bent V-shaped platinum tube with an inner diameter of 4 mm and a wall thickness of 0.25 mm. The platinum tube is placed in a tube furnace (type ROK (F-4) 140, manufactured by Hereus / Hanau), having a regulated heating power of a maximum of 3.75 kW and a heating platinum tube at a length of 2 m. The internal volume of the heated tubular part is 25.13 cm , The internal pressure is measured at the beginning of the platinum pipe, the temperature immediately before the end of the heated tubular part.
    In the course of the reactor, the gas is thermally decomposed and the mixture is introduced into the quenching tower and is rapidly cooled there with 15% by weight HCI aqueous hydrochloric acid to a temperature of 20 ° C. A circulating pump delivers this hydrochloric acid with an adjustable amount of maximum 100 dm / hr through a heat exchanger discharging the decomposition heat-gas mixture to a separator in which the gas mixture and the liquid are separated. The HCI content in hydrochloric acid and the replenishment of the liquid volume consumed with water are kept constant and 15% by weight of HCI hydrochloric acid is fed back to the quenching tower. The decomposition gas mixture after the separator is washed with water, then fed for drying with sulfuric acid, after which it is fed into the gas tank, from which samples are taken for gas chromatographic analysis.
    The results of the experiments are given in table. 1, where the following notation is used: F124 - a mixture of 86% by weight of 1-chloro-1,1,2,2-tetrafluoroethane, 14% by weight of 2-chloro-1,1,1,2-tetrafluoroethane; F226, 1-chloro-1,1.2,2,3,3-hexafluoropropane; SdRv-C - perfluorocyclobutane; TFE - tetrafluoroethylene; F22 - chlorodifluoromethane; Residue I is generally more high boiling than hexafluoropropylene, fluorinated, partially chlorine and hydrogen containing, straight chain, cyclic, saturated and unsaturated hydrocarbons; residue II - as residue I, but additionally chloride
    0 hydrogen and minor amounts of hydrogen fluoride, as well as other fluorinated, partially chlorine- and hydrogen-containing, straight chain, cyclic, saturated, and unsaturated carbon5 hydrogens produced by the reaction as by-products.
    Examples 7-12. The following examples were carried out in the same manner as described for examples 1-6. When
    0 of example 11, however, a mixture of 1-chloro-1,1,2,2-tetrafluoroethane vt 2-chloro-1,1,1,2-tetrafluoroethane was used in a ratio of 54.3: 45.7, and in the case of example 12 - in the ratio of 95.0: 5.0 wt.% (see table. 2).
    5 This method provides good selectivity and high output per unit of space and time. The process of pyrolysis of tetrafluoroethylene in a mixture with 1-chloro-1,1,2,2-tetrafluoroethane
    0 ensures a smooth process and eliminates the uncontrolled flow of the process with the melting of the reactor, often taking place in a known way. In addition, this method ensures the use of non-use industrial waste.
    权利要求:
    Claims (2)
    [1]
    1. A semi-hexafluoropropylene method by thermally splitting a mixture of halogenated hydrocarbons containing 2-chloro-1,1,1,2-tetrafluorozane at 700-900 ° C and 109-300 kPa, characterized in that to simplify
    5 process, as a mixture of halogenated hydrocarbons use a mixture of 54-95 wt.% 1-chloro-1,1,2,2, -tetrafluoroethane and 5- 46 wt.% 2-chloro-1,1,1,2-tetrafluoroethane with chlorhexafluoropropane or specified
    0 mixtures of chlorotetrafluoroethanes with perfluorocyclobutane, and the process is carried out in the presence of 0.4–9.8 mol of tetrafluoroethylene per mole of the initial mixture of halogenated hydrocarbons at a contact time of 0.07–1.2 s.
    five
    [2]
    2. A method according to claim 1, characterized in that prior to thermal decomposition, water vapor is added in an amount of 0.3-1.2 mol per 1 mol of the initial gas mixture of halogenated hydrocarbons and tetrafluoroethylene.
    Priority by featured 03/14/88 - thermal splitting
    mixtures of chlorotetrafluoroethane, tetrafluoroethylene and chlorhexafluoropropane.
    07/09/88 - thermal cleavage of chlorotetrafluoroethane, tetrafluoroethylene and perfluorocyclobutane.
    Table 1
    mixtures of F 124 + F 226 TFB; i - e conversion to the volume of the molar number introduced at a reactor temperature and a pressure of 100 kLa; S in g STC per cm of reaction volume and hour; 6 - recalculated based on the balance of carbon atoms
    Continuation of table 2
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    同族专利:
    公开号 | 公开日
    EP0337127A1|1989-10-18|
    CN1035818A|1989-09-27|
    DE58904105D1|1993-05-27|
    JP2609321B2|1997-05-14|
    CN1018638B|1992-10-14|
    EP0337127B1|1993-04-21|
    JPH01275539A|1989-11-06|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE123647C|1900-03-14|1901-09-24|
    US3446858A|1963-03-30|1969-05-27|Daikin Ind Ltd|Process for the manufacture of hexafluoropropene|
    US3397248A|1964-05-15|1968-08-13|Du Pont|Process for the preparation of hexafluoropropene|
    DE1236497B|1965-02-02|1967-03-16|Fluorwerke Dohna|Process for the production of perfluoropropene|US5057634A|1989-12-19|1991-10-15|E. I. Du Pont De Nemours And Company|Multistep synthesis of hexafluoropropylene|
    US5043491A|1989-12-19|1991-08-27|E. I. Du Pont De Nemours And Company|Multistep synthesis of hexafluoropropylene|
    US5068472A|1989-12-19|1991-11-26|E. I. Du Pont De Nemours And Company|Multistep synthesis of hexafluoropropylene|
    DE4011820A1|1990-04-12|1991-10-17|Hoechst Ag|METHOD FOR PRODUCING MIXTURES FROM CHLORTETRAFLUORETHANE AND OCTAFLUORCYCLOBUTANE|
    US20020032356A1|2000-07-14|2002-03-14|Gelblum Peter Gideon|Synthesis of perfluoroolefins|
    US6924403B2|2002-06-26|2005-08-02|E. I. Du Pont De Nemours And Company|Synthesis of hexafluoropropylene|
    US8436218B2|2010-05-27|2013-05-07|Honeywell International Inc.|Azeotrope-like composition of hexafluoropropane, hexafluoropropene and hydrogen fluoride|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE19883808437|DE3808437A1|1988-03-14|1988-03-14|Process for the preparation of hexafluoropropene|
    DE19883823370|DE3823370A1|1988-07-09|1988-07-09|Process for the preparation of hexafluoropropene|
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