Classifications

• • 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
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/90—Regeneration or reactivation
• • 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
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/48—Liquid treating or treating in liquid phase, e.g. dissolved or suspended
  • B01J38/70—Wet oxidation of material submerged in liquid
• • 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
  • Y02P20/584—Recycling of catalysts

Definitions

• the subject of the present invention is a process for the regeneration of catalysts of the titanium silicalite type, catalysts used in particular in reactions between hydrogen peroxide and an organic co-reactant.
• titanium silicalite as a catalyst, in particular in oxidation reactions of saturated hydrocarbons to form alcohols or ketones, as described in European patent application EP-A-376453 or in reactions of epoxidation of olefins, as described in patent application EP-A-1001 19 or also in hydroxylation reactions of aromatic compounds as reported in application EP-A-200260.
• the activity of these catalysts however drops rapidly. It therefore appears essential to have a means of regenerating them in order to be able to use them repeatedly.
• Patent application JP 03/1 14536 describes a process for regenerating catalysts of the titanium silicalite type by washing with methanol, ketones or benzene. However, this regeneration process does not allow the initial catalytic activity of the catalyst to be recovered quickly and completely.
• the object of the present invention is to provide a process for regenerating catalysts of the titanium silicalite type which is more efficient than the known process. Consequently, the invention relates to a process for regenerating a catalyst of the titanium silicalite type, comprising a treatment of the spent catalyst with a liquid solution, which is characterized in that the liquid solution comprises at least one oxidizing agent chosen from hydrogen peroxide, ozone and organic peroxide compounds.
• organic peroxides which can be used in the process according to the invention are performic acid, peracetic acid and perfluoroperacetic acid. Hydrogen peroxide is preferred.
• the titanium silicalite type catalysts to which the regeneration process according to the invention applies are crystalline synthetic materials with a structure similar to that of zeolites, comprising oxides of silicon and titanium and characterized by an infrared absorption band at about 950-960 cm-1.
• Their general formula is typically: xTiO 2 (lx) SiO 2 in which x is between 0.0001 and 0.5, preferably between 0.001 and 0.05
• TS-1 Materials of this type, known as TS-1, have a microporous crystalline zeolitic structure analogous to that of zeolite ZSM-5
• the properties and the main applications of these compounds are known (B Notari, Structure-Activity and Selectivity Relationship in Heterogeneous Catalysis; RK Grasselli and AW Sleight Editors, Elsevier, 1991, p 243- 256)
• Their synthesis has been studied in particular by A Van der Poel and J Van Hooff (Applied Catalysis A, 1992, Volume 92, pages 93-1 11)
• Other materials of this type have a structure analogous to that of zeolite beta or of zeolite ZSM-1 1
• the liquid regeneration solution may consist essentially of the oxidizing agent.
• it may further comprise a additive or a solvent for the oxidizing agent, that is to say a compound with which the oxidizing agent is completely miscible If necessary, said additive or solvent must be inert with respect to the oxidizing agent, in regeneration conditions
• a polar solvent such as a halogenated solvent, for example trichloromethane, or water is very suitable as solvent for the oxidizing agent Water is particularly advantageous When the used catalyst has been used in a reaction using hydrogen peroxide and an organic co-reagent, the regeneration treatment is generally carried out in the substantial absence of the organic co-reagent
• the liquid solution generally does not contain more than 90% by weight of oxidizing agent.
• a solution containing not more than 50% by weight of oxidizing agent is used.
• a solution containing not more than 20 % by weight of oxidizing agent is used Generally, the liquid solution contains at least 0.5% by weight of oxidizing agent
• it contains at least 1%.
• a very particularly preferred solution in the process according to the invention is an aqueous solution of hydrogen peroxide titrating from 1 to 10% by weight of hydrogen peroxide, preferably from 2 to 5% by weight of hydrogen peroxide
• the treatment of the catalyst with the liquid regeneration solution can be carried out by any suitable means, for example by immersion of the catalyst in the liquid solution when the latter is in the form of dispersed particles or by passage of said solution through the catalyst bed when it is used in a fixed bed Generally, 0.25 to 50 liters of liquid solution is used per kilo of catalyst to be treated. Preferably, 0.5 to 10 liters are used per kilo of catalyst.
• the oxidizing agent can be introduced during the treatment continuously, discontinuously (by successive introductions of several doses of oxidizing agent) or by introduction of a single dose of oxidizing agent at the start of the treatment.
• the treatment of the catalyst with the liquid solution is generally carried out at a temperature between room temperature and the boiling temperature of the solution.
• a regeneration temperature of at least 50 ° C and not exceeding 100 ° C is preferred.
• Treatment with an aqueous solution of hydrogen peroxide at a temperature close to about 90 ° C has given excellent results.
• the pressure at which the process according to the invention is carried out is not critical in itself as long as it is sufficient to maintain the solution essentially in liquid form.
• the process for regenerating the catalyst comprises washing the catalyst prior to treatment with the liquid solution containing the oxidizing agent in order to remove substantially all of the compounds with which the catalyst has been in contact in the reaction in which it has been implemented. Washing consists in bringing the catalyst into contact with water or with an organic compound.
• Organic compounds are preferred. These indeed make it possible to avoid the formation of two distinct phases. In addition, they have a high solubility of the organic compounds responsible for the deactivation of the catalysts.
• the organic compounds can be chosen from aliphatic, cyclic, aromatic, alcoholic organic diluents. They preferably contain up to 20 carbon atoms. Alcohols are fine. Methanol is particularly preferred. It can be interesting to use, for washing, the diluent used when using the catalyst
• the washing temperature is generally 25 ° C. at the boiling temperature of the organic washing compound. This washing is carried out by bringing the catalyst into contact with water or with the organic compound for a period of 5 minutes to 2 hours. Preferably, the washing step does not exceed 30 minutes. In a particularly advantageous manner, the washing comprises a first washing step with an organic compound and a second washing step with water.
• the method according to the invention makes it possible to restore almost all the initial activity of the catalyst by a short-term treatment
• Controlling the pH during treatment can be advantageous This in fact makes it possible to avoid corrosion of the equipment used for the treatment In addition, this makes it possible, when the catalyst is dispersed in a binder, to prevent attack binder by the acids released during the treatment
• a control of the pH also makes it possible to limit the decomposition of the oxidizing agent by metals released during the treatment
• the pH is maintained at a value of at least 2, in particular at minus 4
• the pH does not usually exceed 8, preferably 7
• alkaline pHs can affect the activity of the catalyst.
• the operation is preferably carried out at a pH maintained in the range from 2 to 8, more particularly from 4 to 7. pH can be controlled by adding alkali, for example sodium hydroxide
• the process according to the invention applies to used titanium silicalite catalysts, in particular those used in a reaction using hydrogen peroxide and an organic co-reagent, in particular those used in epoxidation reactions of olefins, hydroxylation of aromatic compounds or oxidation of saturated hydrocarbons. It applies more particularly to catalysts used in olefin epoxidation reactions using hydrogen peroxide. It is particularly applicable to catalysts used in the epoxidation reaction of allyl chloride to epichlorohydrin. In addition, the process can be applied to catalysts used in the epoxidation reaction of propylene to propylene oxide by means of hydrogen peroxide
• the invention therefore also relates to a process for the synthesis of epoxides by reaction between an olefin and hydrogen peroxide in the presence of a catalyst regenerated by means of the regeneration process described above, in which a liquid effluent from the synthesis of epoxides is recycled and used for the regeneration of the catalyst.
• Example 1 The invention is more fully illustrated in the following nonlimiting examples.
• Example 1 The invention is more fully illustrated in the following nonlimiting examples.
• the catalyst was washed in a similar manner with water at 75 ° C. The water was removed, then the catalyst was treated analogously with a 3.5% by weight aqueous solution of hydrogen peroxide at 85 ° C for 1 hour. The aqueous solution was drained and the reactor was again supplied with the solution of allyl chloride and hydrogen peroxide in methanol, under the conditions set out above. 11 cycles such as that described above for use / regeneration of the catalyst were carried out. At each cycle, the activity of the regenerated catalyst was measured by determining the amount of epichlorohydrin produced under these conditions before the conversion rate of hydrogen peroxide fell again by 25% compared to its initial value measured after one hour walk. A constant activity of 127 grams of epichlorohydrin was observed during each of the 11 cycles.
• Example 2 Example 2
• Example 1 was repeated, but using a liquid solution containing 1.06% hydrogen peroxide at a temperature of 86 ° C.
• the yield of epichlorohydrin was 117 grams.
• Example 3 (comparison)
• Example 1 was repeated but using as liquid solution water free of hydrogen peroxide at 85 ° C for 1 hour.
• the yield of epichlorohydrin was 90 grams.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Epoxy Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)

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• 1996
  • 1996-10-25 BE BE9600912A patent/BE1010717A3/fr not_active IP Right Cessation
• 1997
  • 1997-10-09 CA CA002268872A patent/CA2268872A1/fr not_active Abandoned
  • 1997-10-09 WO PCT/EP1997/005688 patent/WO1998018555A1/fr not_active Ceased
  • 1997-10-09 BR BR9712565-2A patent/BR9712565A/pt not_active IP Right Cessation
  • 1997-10-09 NZ NZ335404A patent/NZ335404A/xx unknown
  • 1997-10-09 AU AU48675/97A patent/AU4867597A/en not_active Abandoned
  • 1997-10-09 EP EP97911226A patent/EP0958049A1/de not_active Withdrawn
  • 1997-10-14 TW TW086115057A patent/TW342353B/zh active
  • 1997-10-24 AR ARP970104929A patent/AR010027A1/es unknown
• 1999
  • 1999-04-20 US US09/294,364 patent/US6063941A/en not_active Expired - Fee Related

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