Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
  • B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
• • 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
  • Y02P20/10—Process efficiency

Definitions

• the present invention relates to a process for the manufacture of ethyl acetate comprising reacting ethyl alcohol with acetic acid in the presence of a solid acid catalyst and simultaneously separating the reaction components by distillation in a reactive distillation device comprising at least three zones: a reaction zone in which the reaction proceeds simultaneously with the separation by distillation of the components in an upper separation zone and in a lower separation zone.
• the organic phase obtained in the upper separation zone being isolated and partially refluxed in the reaction zone.
• Esters of acetic acid are generally used as organic solvents.
• ethyl acetate is used in particular in the field of cosmetics, perfumery, in glues, paints and varnishes.
• a higher or lower purity is required and it is common to require that the amount of acetic acid present in ethyl acetate is less than 0.01% by weight.
• the manufacturing processes of ethyl acetate must lead to a quality product. Since ethyl acetate is a common consumer product, at high volume, it is important that its manufacturing process is the most efficient possible, in terms of productivity and energy balance.
• the object of the present invention is to provide an improved process for preparing a carboxylic acid ester in terms of process economics.
• the subject of the present invention is therefore a process for the production of ethyl acetate by reaction of ethyl alcohol with acetic acid in the presence of a solid acid catalyst and during the simultaneous separation by distillation of the reaction components in a system of reactive distillation, in which the starting components are acetic acid and ethyl alcohol and are introduced separately or simultaneously with a molar ratio of acetic acid to ethyl alcohol of between 0.85 and 0.97 (limits included) in a system in which the reaction zone is centrally located between an upper separation zone and a lower separation zone, the reaction proceeds simultaneously with the separation by distillation of the components having different boiling points while the separation of the components takes place in said upper and lower separation zones, the ratio between the feed of the compo In the system, the reflux flow from the organic phase of the upper reaction zone to the reaction location is between 1.0 and 1.5 (limits included).
• the process according to the present invention also has the advantage of not or practically not generating acetic acid at the bottom of a reactive distillation column. This avoids subsequent treatment or recycling steps without loss of raw material; thus making the process even more economical.
• the molar ratio of acetic acid to ethyl alcohol is preferably between 0.90 and 0.95 (limits included).
• the ratio between the feed of the starting components in the system and the return flow of reflux from the organic phase of the upper reaction zone to the reaction location is preferably between 1, 1 and 1, 4, very preferably between 1, 15 and 1, 4.
• the catalyst involved in the process of the invention is a solid acid catalyst, said heterogeneous.
• the heterogeneous acid catalysts of the invention are preferably sulphonic resins or zeolites.
• the zeolites that can be used are, for example, those cited in WO2007 / 099071.
• Resins suitable for the present invention may be a polystyrenic or polyacrylic backbone which carries sulfonic functional groups. Thus, it is possible to use the sulfonic resins existing on the market, resins marketed under different trade names.
• esterification resins can be mentioned, among others: Amberlyst® 15 and 36 from Rhom Haas, Amberlite® IR-120 H from Rhom Haas, Lewatit® 2631 from Bayer and K1431 from Bayer.
• the acidity of these resins is for example between 1 and 10 eq / kg (H +).
• These resins are in particular implemented in a fixed or fluidized bed, preferably in a fixed bed.
• the quantity of catalyst introduced is such that the amount present in the reactor is preferably between 0.1 and 2% by weight relative to the reaction medium.
• the reaction zone of the reactive distillation column generally comprises at least one catalytic esterification bed.
• the catalyst may be enclosed in at least one permeable envelope, for example an envelope made of fabric, of synthetic material, for example polypropylene, or metal fabric.
• the catalyst can also be arranged in bulk, that is to say freely, inside each catalytic bed of the catalytic zone. In this case, to maintain the catalyst in place and to prevent it being driven by the liquid stream flowing through it, it is generally provided that any catalytic bed included in the catalytic zone rests on any device allowing the passage of the liquid but impermeable catalytic particles, such as for example a Johnson-type grid or Johnson-type nozzles evenly distributed on a surface impervious to gaseous, liquid or solid flows.
• the catalyst When the catalyst is arranged in bulk, it can be used in the form of fixed bed, expanded bed or fluidized bed.
• the catalysts may be immobilized on the surface of inert supports such as metal grids or silica elements which form a fixed structure, called a fixed bed, or a moving structure, called a fluidized bed, placed in the reactor.
• inert supports such as metal grids or silica elements which form a fixed structure, called a fixed bed, or a moving structure, called a fluidized bed, placed in the reactor.
• One of the most used packing is the Sulzer Katapak which is formed by a stack of corrugated metal plates between which are arranged the catalyst particles
• the esterification reaction is most preferably carried out in a continuous mode.
• a reactive distillation device suitable for the implementation of the process mention may be made especially of that mentioned in patent EP1220829 and comprising a reaction zone placed centrally between an upper separation zone and a lower separation zone.
• the acetic acid is preferably introduced into the reaction zone or above this zone at a location above the location of the supply of ethyl alcohol.
• the ethyl alcohol provided is preferably introduced into the reaction zone or under this zone.
• the acetic acid thus introduced may also comprise at least one other compound, in particular one of the compounds selected from the group consisting of: ethyl acetate, water, and ethyl alcohol.
• the temperature of the reaction is between 50 and 150 ° C, preferably between 80 and 100 ° C.
• the reaction is preferably carried out at atmospheric pressure.
• a pressure slightly above or below atmospheric pressure may also be suitable.
• the reaction is advantageously carried out at a pressure such that the reaction mixture is partially in the liquid state.
• the process of the invention can be implemented, for example, at an absolute pressure of between 0.5 and 5 bar absolute, and even more preferably between 0.5 and 1.5 bar.
• the medium leaving the lower separation zone of the system also called the bottom medium of the reactive distillation system, preferably comprises less than 1% by weight of acetic acid.
• the medium leaving the lower separation zone of the system also called the bottom medium of the reactive distillation system, can comprise in particular:
• This medium preferably comprises less than 0.5% by weight of acetic acid.
• the medium leaving the upper zone of separation of the system also called medium at the top of the reactive distillation system, can comprise in particular:
• the volatile mixture is then separated, cooled to a temperature in particular of between 5 and 70 ° C., and then separated in the aqueous phase and in the organic phase.
• This organic phase is isolated and partially refluxed in the system.
• the ratio between the starting components and the reflux of the organic phase is between 1.0 and 1.5, preferably between 1.1 and 1.4, very preferably between 1.15 and 1.4.
• the present invention also relates to a device for implementing the method of the invention.
• the skilled person is perfectly able to choose the means to implement depending on the separation to be performed. We will simply recall the following.
• the size and in particular the diameter of the reactive distillation columns depends on the circulating flow and the internal pressure. Their sizing will therefore be mainly according to the mixing rate to be treated.
• the internal parameter that is the number of theoretical stages is determined in particular by the purity of the starting compound and the purities of the products to be obtained at the top and bottom of distillation. It will be specified that the column may be lined with either trays or ordered or woven packing, as is perfectly known to those skilled in the art. The installation being determined, the person skilled in the art adjusts the operating parameters of the column.
• a reactive distillation column according to EP 1220829 is used for a final production of 100 kg / h of ethyl acetate with different molar ratios of substrate and various reflux.
• the acidic solid catalyst used is Amberlyst 36wet. This column comprises 25 theoretical plates. It operates at a pressure of 1.013 bar absolute and at a column temperature of 100 ° C. The results are mentioned in the following Table 1:
• the molar ratio corresponds to the acetic acid / ethanol molar ratio.
• the Specific Unit Consumption of steam is expressed in tonnes of heating water vapor per tonne of ester produced.
• the reflux ratio corresponds to the ratio between the total feed rate of the starting components and the reflux rate of the organic phase.
• the transformation rate (TT) of ethanol is measured continuously and in steady state. They are calculated by the ratio of the number of moles of ethanol consumed in the reaction (converted to ester) over the number of moles of ethanol fed.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
• Steroid Compounds (AREA)

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• 2011
  • 2011-03-17 FR FR1152175A patent/FR2972725B1/fr not_active Expired - Fee Related
• 2012
  • 2012-03-06 BR BR112013023249A patent/BR112013023249A2/pt not_active IP Right Cessation
  • 2012-03-06 WO PCT/EP2012/053777 patent/WO2012123279A1/fr active Application Filing
  • 2012-03-06 EP EP12707104.1A patent/EP2686292A1/fr not_active Withdrawn
  • 2012-03-06 CN CN201280011225.6A patent/CN103402968B/zh not_active Expired - Fee Related
  • 2012-03-16 AR ARP120100868A patent/AR085420A1/es not_active Application Discontinuation

Non-Patent Citations (1)

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