Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D301/00—Preparation of oxiranes
  • C07D301/02—Synthesis of the oxirane ring
  • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
  • C07D301/12—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with hydrogen peroxide or inorganic peroxides or peracids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• the present invention relates to a process for the manufacture of oxirane by reaction between an olefin and a peroxide compound in the presence of a catalyst and a solvent.
• it relates to the manufacture of propylene oxide (or epichlorohydrin) by epoxidation of propylene (or allyl chloride) using hydrogen peroxide in the presence of a catalyst containing TS-1.
• propylene oxide or epichlorohydrin
• epoxidation of propylene or allyl chloride
• the present invention aims to remedy this drawback by providing a new method of high selectivity, while keeping a high activity (or reaction rate).
• the invention relates to a process for the manufacture of oxirane by reaction of an olefin with a peroxide compound in the presence of a catalyst and of a solvent in at least two reactors arranged in series, each of which contains part of the catalyst, according to which a first part of the olefin, the solvent and the peroxide compound are introduced into a first reactor, an epoxidation of the first part of the olefin is carried out therein to form a first part of the oxirane, it is withdrawn of this reactor a medium comprising the first part of oxirane formed, the solvent, the unconverted olefin and, if appropriate, the peroxide compound not consumed, the medium is introduced into a distillation column, the major part of the oxirane formed is collected at the top of the column and of the unconverted olefin,
• distillation The function of distillation is to eliminate the oxirane as soon as possible as soon as it forms in the reaction medium to prevent it from coming into contact with the other constituents of the reaction medium and to prevent by-products from being thus formed.
• This separation is carried out in a distillation column separate and distinct from the epoxidation reactor. Since the catalyst does not leave the epoxidation reactor, distillation is therefore carried out in the absence of the epoxidation catalyst in order to avoid contact between the oxirane formed and the epoxidation catalyst because it promotes the formation by-products. Distillation makes it possible to separate most of the oxirane formed from the epoxidation reaction medium. This major part is generally greater than or equal to 80% of the amount of oxirane formed in the first reactor. It is most often greater than or equal to 90%. Usually it is less than or equal to 99%. In particular less than or equal to 95%.
• the conditions under which the distillation is carried out depend on the nature of the oxirane (and in particular its boiling temperature), on its concentration in the medium introduced into the distillation column, on the nature of the other constituents of the medium (l unconverted olefin and solvent), their boiling point and the desired distillation yield.
• Distillation is generally carried out at a temperature greater than or equal to 10 ° C, preferably greater than or equal to 35 ° C, values greater than or equal to 45 ° C being recommended.
• the temperature is usually less than or equal to 125 ° C, most often less than or equal to 100 ° C, values less than or equal to 90 ° C being preferred.
• Distillation is commonly carried out at a pressure greater than or equal to 0.1 bar, preferably greater than or equal to 0.5 bar, the values greater than or equal to 1 bar being the most common.
• the pressure is generally less than or equal to 10 bar, in particular less than or equal to 5 bar, values less than or equal to 2 bar being very particularly recommended.
• any reference to the distillation pressure corresponds to the absolute pressure measured at the top of the distillation column.
• the distillation column which can be used in the process according to the invention is known in itself. It is possible to use, for example, a column with conventional trays or a column with trays of the "dual-flow" type or else a column with loose or structured stacking.
• the number of theoretical plates in the distillation column is generally greater than or equal to 20, more especially greater than or equal to 30. A number less than or equal to 80 gives good results. A number less than or equal to 60 is recommended.
• the molar reflux rate (which corresponds to the molar flow rate of liquid returned to the head of the column reduced to the whole of the distillate - vapor more liquid - taken off at the head of the column) in the column to be distilled is usually greater than or equal to 0.5 , preferably greater than or equal to 0.8. This rate is commonly less than or equal to 5, most often less than or equal to 2.5.
• an installation is implemented comprising at least two epoxidation reactors arranged in series and linked together. Each reactor is supplied with olefin. The peroxide compound and the solvent are introduced into the first reactor. Fresh peroxide compound can also be introduced into one or more of the subsequent reactors. Each reactor contains a part of the catalyst which does not leave this reactor.
• the catalyst When the catalyst is present in the form of a fixed bed, it is generally not necessary to take precautions to keep the catalyst in the reactor.
• the catalyst may be present in the form of particles, at least part of which is in the fluidized state by a liquid stream or by mechanical stirring or by a gas.
• a liquid stream When using a liquid stream, it is recommended to provide a clearance zone surmounting the fluid bed to stop the particles of catalyst which are in motion and / or to provide a filter at the outlet of the reactor.
• the installation can obviously include more than two reactors connected in series.
• the first reactor in the series is supplied with the olefin, the peroxide compound, the solvent (and optionally a fraction of the medium obtained at the bottom of the distillation column corresponding to this reactor) and each subsequent reactor is supplied with the olefin, the balance of the medium coming from the preceding reactor of the series and possibly the fresh peroxide compound.
• Preferably 3 reactors are used in series.
• reactors of identical size are preferably used. This makes it possible to swap the function of the reactors when the deactivated catalyst of a reactor is replaced by fresh or regenerated catalyst without disturbing the operation of the installation (so-called "carousel” operation).
• each subsequent reactor in the series is followed by a distillation column, called in the following "subsequent distillation".
• This subsequent distillation has the same function as the intermediate distillation carried out between the first and second epoxidation.
• the conditions for subsequent distillations are similar to the conditions described above for intermediate distillation.
• the medium leaving the subsequent reactor and containing the other part of the oxirane, the solvent, the unconverted olefin and, if appropriate, the peroxide compound not consumed is introduced into a distillation column.
• the other part of the oxirane and the unconverted olefin are collected at the top of the column, and the solvent and optionally the unconsumed peroxide compound at the bottom of the column.
• the medium collected at the bottom of the second distillation column can be recycled in the first reactor.
• the mixture of oxirane and unconverted olefin collected at the top of the distillation column (first and / or subsequent) is introduced into a container in which the oxirane is separated unconverted olefin.
• This unconverted olefin can then be recycled in one of the reactors, preferably in the first reactor.
• the container may contain a condenser or an absorbent liquid or an absorbent solid or a permoselective membrane.
• the condensers are suitable.
• a third embodiment of the process according to the invention consists in using the catalyst in the form of particles, at least part of which is in the fluidized state, as described in the applicant's patent application filed on the same day as this.
• the medium entering the distillation column (first and / or subsequent) is first subjected to an expansion before being introduced into this distillation column.
• This form is particularly suitable when the epoxy dation is carried out under pressure or in the presence of a gaseous compound.
• This gaseous compound can be the olefin itself (for example propylene) or an inert gas which is introduced into the epoxidation reaction medium to allow the oxirane to be drawn in and out of the reactor, as described in Patent application WO 99/48883 from the applicant.
• the entire peroxide compound is introduced into the first reactor, as described in the applicant's patent application filed on the same day and entitled "Process for the manufacture of oxirane at using a peroxide compound "(the content of which is incorporated by reference).
• the subsequent reactor (s) are therefore not supplied with fresh peroxide compound but only with the peroxide compound which is present in the medium originating from the preceding reactor and which has not been consumed in this preceding reactor.
• water is also introduced with the peroxide compound into the first reactor.
• the first reactor 1 contains part of the catalyst, preferably in a fluid bed 2.
• the reactor 1 is supplied with a first part of the olefin via line 3 and then through line 4, with peroxide compound through line 5 and then through line 4 , and in solvent via the conduit 4 coming from another part of the installation which is described below.
• the first part of the olefin reacts with the peroxide compound in the presence of the catalyst to form a first part of the oxirane.
• the medium leaving the reactor 1 via the line 6 contains the solvent, the first part of the oxirane, the unconsumed peroxide compound and the unconverted olefin.
• This medium passes through a filter 7, and is sent via the conduit 8 to the container 9 where it is subjected to an expansion.
• the medium is then transported via line 10 in a distillation column 11. At the head of this distillation column 11, a mixture of oxirane and unconverted olefin is recovered.
• This mixture is sent via line 12 to a condenser 13 which separates the oxirane from the unconverted olefin.
• the unconverted olefin is recycled to reactor 1 via lines 14, 3 and 4.
• the first part of oxirane is collected as finished product via line 15.
• a medium is collected containing the solvent, the peroxide compound not consumed in reactor 1 and optionally a part of the unconverted olefin.
• This medium, part of which can optionally be recycled in the reactor 1 via the line 30 is transported via the line 16 into a second reactor 17 containing another part of the catalyst, preferably in the form of a fluid bed 18.
• the second reactor 17 is supplied with a second part of the olefin via the line 19.
• the second part of the olefin reacts with the unconsumed peroxide compound coming from the first reactor in the presence of the catalyst 18 to form a second part of oxirane.
• the conditions in the second reactor 17 are preferably such that all of the peroxide compound from the first reactor is consumed.
• the medium leaving the reactor 17 via the line 20 then contains the solvent, the second part of the oxirane and the unconverted olefin.
• This medium passes through a filter 21, and is sent via the conduit 22 to the container 23 where it is subjected to an expansion.
• the medium is then transported via line 24 in a second distillation column 25. At the head of this distillation column 25, a mixture of the second part of oxirane and unconverted olefin is recovered.
• the catalyst used in the process according to the invention generally contains a zeolite as an active element, and preferably a titanium zeolite.
• titanium zeolite is intended to denote a solid containing silica which has a microporous crystalline structure of the zeolite type and in which several silicon atoms are replaced by titanium atoms.
• the titanium zeolite advantageously has a crystal structure of the ZSM-5, ZSM-11, ZSM-12, MCM-41, ZSM-48 type. It can also have a crystalline structure of the beta zeolite type, preferably free of aluminum. Zeolites having an infrared absorption band at about 950-960 cm -1 are well suited. Titanium zeolites of the silicalite type are preferred.
• xTi ⁇ 2 (lx) Si ⁇ 2 in which x is from 0.0001 to 0.5, preferably from 0.001 to 0.05, are effective.
• Materials of this type known as TS-1, exhibit a microporous crystalline zeolite structure analogous to that of zeolite ZSM-5.
• the catalyst used in the process according to the invention is advantageously in the form of particles obtained by extrusion as described in patent application WO 99/28029 of the applicant, or by a spray process as described in the patent application WO 99/24164 of the applicant.
• the content of these two patent applications is incorporated by reference therein.
• the solvent used in the process according to the invention can be chosen from saturated, linear or branched aliphatic alcohols.
• the alcoholic solvent generally contains up to 10 carbon atoms, preferably from 1 to 6 carbon atoms. Mention may be made, by way of examples, of methanol and ethanol. 'Methanol is preferred.
• the amount of solvent used in the first reactor is generally at least 25% by weight of the liquid reaction medium present in the first reactor, in particular at least 40% by weight, for example at least 50 % in weight. This amount usually does not exceed 99% in. weight, especially not 95% by weight.
• the molar ratio between the amounts of olefin and of peroxide compound used in the process according to the invention is generally at least 0.1, in particular at least 0.2, and preferably at least 0.5 . This molar ratio is most often at most 100, in particular at most 50 and preferably at most 25.
• the process according to the invention can be continuous or discontinuous.
• the peroxide compound when it is carried out continuously, is generally used in the first reactor in an amount of at least 0.005 mol per hour and per gram of catalyst present in the first reactor, in particular, at least 0.01 mole.
• the amount of peroxide compound is usually less than or equal to 25 moles and, in particular, less than or equal to 10 moles.
• a preference is shown for an amount of peroxide compound greater than or equal to 0.03 mol and less than or equal to 2.5 mol.
• the peroxide compound is advantageously used in the form of an aqueous solution.
• the aqueous solution contains at least 2% by weight of peroxide compound, in particular at least 5% by weight. It most often contains a maximum of 90% by weight of peroxide compound, in particular 70% by weight.
• the reaction temperature between the olefin and the peroxide compound can vary from 10 to 125 ° C. In an advantageous variant as described in patent application EP99 / 08703 of the applicant, it is greater than 35 ° C to remedy the gradual deactivation of the catalyst.
• the temperature can be greater than or equal to 40 ° C and preferably greater than or equal to 45 ° C. A temperature greater than or equal to 50 ° C. is very particularly preferred.
• the reaction temperature is preferably less than 100 ° C.
• the reaction between the olefin and the peroxide compound can take place at atmospheric pressure. It can also take place under pressure. Generally, this pressure does not exceed 40 bar. A pressure of 20 bar is well suited in practice.
• the peroxide compounds which can be used in the process according to the invention are the peroxide compounds containing one or more functions. peroxide (-OOH) which can release active oxygen and capable of carrying out epoxidation. Hydrogen peroxide and peroxide compounds which can produce hydrogen peroxide under the conditions of the epoxidation reaction are well suited. Hydrogen peroxide is preferred. When using hydrogen peroxide, it may be advantageous to use in the process according to the invention an aqueous solution of hydrogen peroxide in the raw state, that is to say unpurified.
• AO auto-oxidation process For example, we can implementing a solution obtained by simple extraction with substantially pure water of the mixture resulting from the oxidation of at least one alkylanthrahydroquinone (process called "AO auto-oxidation process") without subsequent washing and / or purification treatment .
• These crude hydrogen peroxide solutions generally contain from 0.001 to 10 g / 1 of organic impurities expressed as TOC (Total Organic Carbon). They usually contain metal cations (such as alkali or alkaline earth metals, such as sodium) and anions (such as phosphates, nitrates) in contents of 0.01 to 10 g / l.
• TOC Total Organic Carbon
• metal cations such as alkali or alkaline earth metals, such as sodium
• anions such as phosphates, nitrates
• the oxirane which can be prepared by the process according to the invention is an organic compound comprising a group corresponding to the general formula:
• Oxirane generally contains from 2 to 10 carbon atoms, preferably from 3 to 6 carbon atoms.
• the oxirannes which can be advantageously prepared by the process according to the invention are the
• the olefins which are very suitable in the process according to the invention generally contain from 2 to 10 carbon atoms and preferably 3 to 6 carbon atoms.
• Propylene, butylene and allyl chloride are well suited. Propylene and allyl chloride are preferred. Propylene is particularly preferred.
• the pH of the liquid phase it may prove advantageous to control the pH of the liquid phase.
• This base can be introduced into a single reactor (for example, the first reactor) or into several reactors. It is preferably introduced into each reactor.
• the reaction between the olefin and the peroxide compound can be carried out in the presence of a salt such as sodium chloride, as described in patent application WO EP99 / 08703 by the applicant (the content of which is incorporated by reference into the present patent application).
• This salt can be introduced into a single reactor (for example, the first reactor) or into several reactors. It is preferably introduced into each reactor.
• a fluid containing the olefin and also at least 10% (in particular 20%, for example at least 30%) by volume of one or more alkanes can be introduced into the epoxidation reactors.
• this can be mixed with at least 10% by volume of propane when the recycled unconverted propylene is introduced into the reactor.
• propane can also be a source of propylene that has not been completely purified of propane.
• Examples 1 and 2 were calculated using the ASPEN PLUS ® software from the company ASPEN TECHNOLOGY INC. using the kinetic parameters of the reaction determined on the basis of the experimental tests described and the liquid-vapor equilibria available in the literature.
• the reaction mixture is introduced continuously at 70 ° C. into a methodical reactor containing 600 kg of catalyst.
• the reactor effluent is mixed with 200 kmol / h of propylene at a pressure sufficient to dissolve all of the propylene at the reaction temperature and introduced continuously at 70 ° C. into a second methodical reactor containing 600 kg of catalyst.
• the effluent from the second reactor contains 2.3 kmol / h of unconverted hydrogen peroxide, 243.9 kmol / h of propylene oxide and 77.4 kmol / h of by-products (mainly methoxypropanol and propanediol); the C3 yield reaches 74.7% for a conversion rate of hydrogen peroxide of 99.3%.
• the synthesis of propylene oxide is carried out in 2 reactors in series with intermediate separation of the propylene oxide formed in the first reactor.
• 326.5 kmol / h of hydrogen peroxide accompanied by 1100 kmol / h of water are mixed with 1500 kmol / h of methanol and 250 kmol / h of propylene under a pressure sufficient to dissolve all the propylene at the reaction temperature.
• the reaction mixture is introduced continuously at 70 ° C. into a methodical reactor containing 600 kg of catalyst.
• the reactor effluent is directed to a rectification column containing 50 theoretical plates (including condenser and boiler); the power is performed at the l ⁇ th theoretical plate (counted from the condenser); the column is operated at 1.1 bar absolute (column head pressure); the column head temperature is maintained at 40 ° C (partially vaporized distillate); the molar reflux rate is fixed at 1; the distillate flow rate is adjusted so as to recover 95% of the propylene oxide present in the column feed at the head of the column.
• the mixture drawn off at the bottom of the column, depleted in propylene oxide, is mixed with 200 kmol / h of propylene at a pressure sufficient to dissolve all of the propylene at the reaction temperature and introduced continuously at 70 ° C. into a second methodical reactor containing 600 kg of catalyst.
• the effluent from the second reactor contains 0.5 kmol / h of unconverted hydrogen peroxide, 85.9 kmol / h of propylene oxide and 68.5 kmol / h of by-products (mainly methoxypropanol and propanediol); the column distillate contains 168.8 kmol / h of propylene oxide; the C3 yield reached 78.0% for a conversion rate of hydrogen peroxide of 99.9%.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Epoxy Compounds (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)

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• 2000
  • 2000-06-28 FR FR0008354A patent/FR2810982B1/fr not_active Expired - Lifetime
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