EP3197860A1 - Procédé de préparation de diesters d'acide téréphtalique comportant un enrichissement par recyclage de l'alcool - Google Patents

Procédé de préparation de diesters d'acide téréphtalique comportant un enrichissement par recyclage de l'alcool

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Publication number
EP3197860A1
EP3197860A1 EP15766174.5A EP15766174A EP3197860A1 EP 3197860 A1 EP3197860 A1 EP 3197860A1 EP 15766174 A EP15766174 A EP 15766174A EP 3197860 A1 EP3197860 A1 EP 3197860A1
Authority
EP
European Patent Office
Prior art keywords
alcohol
reactor
reaction
terephthalic acid
suspension
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.)
Withdrawn
Application number
EP15766174.5A
Other languages
German (de)
English (en)
Inventor
Armin Schraut
Martin KALLER
Rob BRONNEBERG
Jasmin STAMMER
Martin DAS
Gerrit HARNISCHMACHER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP3197860A1 publication Critical patent/EP3197860A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
    • B01D3/36—Azeotropic distillation
    • 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
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B01J19/0013—Controlling the temperature of the process
    • 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
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
    • B01J19/0066—Stirrers
    • 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
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/48—Separation; Purification; Stabilisation; Use of additives
    • C07C67/58—Separation; Purification; Stabilisation; Use of additives by liquid-liquid treatment
    • 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
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00094—Jackets

Definitions

  • the invention relates to a process for the preparation of terephthalic diesters by reacting terephthalic acid with at least one alcohol.
  • Esters of terephthalic acid are used as plasticizers and are characterized by favorable toxicological properties.
  • carboxylic acid esters by reacting carboxylic acids with alcohols. This reaction can be carried out autocatalytically or catalytically, for example by Brönstedt or Lewis acids. Regardless of the type of catalysis, there is always a temperature-dependent equilibrium between the starting materials (carboxylic acid and alcohol) and the products (esters and water).
  • an entraining agent is generally used, with the aid of which the water of reaction is removed from the batch. If one of the starting materials (alcohol or carboxylic acid) boils lower than the ester formed and forms a miscibility gap with water, an educt can be used as entraining agent and recycled to the batch after removal of water.
  • the alcohol used is usually the
  • the alcohol used as the entraining agent it is customary to at least partially condense the vapors from the reactor, to separate the condensate into an aqueous phase and an organic phase essentially consisting of the alcohol used for the esterification, and at least partially separate the organic phase returns to the reactor.
  • EP-A 1 186 593 describes a process for the preparation of carboxylic acid esters by reaction of di- or polycarboxylic acids or their anhydrides with alcohols, wherein the water of reaction is removed by azeotropic distillation with the alcohol. The amount of liquid removed from the reaction by the azeotropic distillation is completely or partially replenished with the alcohol.
  • WO 2010/076192 A1 proposes removing low-boiling components from the organic phase to be recycled in order to prevent their accumulation in the reactor system.
  • No. 7,276,621 B2 describes a process for the titanate-catalyzed esterification of terephthalic acid with 2-ethylhexanol. An inert gas is passed through the reaction mixture to aid in the removal of water.
  • JP 4956945 B2 also describes a process for the esterification of terephthalic acid with 2-ethylhexanol.
  • the terephthalic acid is introduced as a slurry continuously lent or discontinuous in the reaction system.
  • the metered addition takes place at the same rate at which the terephthalic acid is converted to the product.
  • No. 7,799,942 B2 describes a process for the preparation of terephthalic acid diesters in a reactor at atmospheric pressure using a distillation column placed on the reactor. In addition, the reaction mixture is flowed through by an inert gas.
  • No. 7,385,075 B2 describes a process for preparing esters of polybasic C 4 -C 10 -carboxylic acids and C 3 -C 8 -alcohols by heating in the presence of a catalyst.
  • the vapor is rectified into an alcohol-rich phase and a water-rich phase.
  • the alcohol-rich phase is recycled to the reaction mixture; the water-rich phase is condensed and at least partially discharged.
  • WO 2010/076193 A1 describes a process for the purification of the crude ester product of an esterification reaction in which a metal-containing esterification catalyst is used.
  • US 2014/0148612 A1 describes a process for the preparation of esters in which a reaction mixture of an acid or an anhydride is brought to reaction temperature with an excess of alcohol by supplying energy, wherein the supply of energy is initially throttled in order to avoid foaming, and the Energy supply can then be increased.
  • the solubility of terephthalic acid in higher alcohols is low.
  • terephthalic acid in 2-ethylhexanol at 180 ° C is only less than 0.65 wt .-% soluble.
  • the reaction of terephthalic acid with higher alcohols proceeds only via the part of terephthalic acid dissolved in the alcohol.
  • the invention is therefore based on the object to provide a process for the preparation of terephthalic acid diesters, which allows a simple entry of terephthalic acid into the reactor and reaches a complete conversion of terephthalic acid.
  • Another object of the invention is to provide a process that can be carried out in existing reactors for esterification reactions by minor conversions.
  • the present invention therefore provides a process for the preparation of a terephthalic acid diester by reacting terephthalic acid with at least one alcohol, wherein a) terephthalic acid is suspended in a dispersing kettle in the alcohol to obtain a presuspension, b) the presuspension is passed from the dispersing vessel into a reactor and reacting in the presence of an esterification catalyst, and c) distilling off water of reaction as alcohol-water azeotrope with the vapor, at least partially condensing the vapor, separating the condensate into an aqueous phase and an organic phase and passing the organic phase over a column, in which at least part of the vapor is fed to the organic phase, the organic phase is collected in the lower region of the column and passed at least partly into the dispersing vessel and / or temporarily stored in a collecting container and used for the same batch or a subsequent batch from the collection Be fiscale r passes into the dispersing kettle.
  • the process according to the invention can be
  • the process obviates the problems associated with metering solid terephthalic acid into the reactor, such as clumping of the terephthalic acid and clogging of the screw conveyor or other conveyor.
  • the process provides for the preparation of a pre-suspension in a dispersing vessel.
  • Terephthalic acid is not metered as a solid but in the form of a suspension in the reactor.
  • powdered terephthalic acid is suspended in the dispersing kettle in a partial amount or the total amount of the alcohol.
  • a suitable mixing device is used.
  • an amount of the terephthalic acid can be mixed with alcohol using an agitator; alternatively, dispersing pumps can be used. In this case, for example, the entire amount of terephthalic acid can be suspended in one step or in the course of the process
  • Terephthalic acid are suspended in portions.
  • terephthalic acid may be used e.g. be metered into the dispersing vessel by means of a screw conveyor.
  • the mixing can also take place in a closed chamber by the interaction of a rotating rotor and a stator, whereby only one incremental quantity of the components is continuously mixed with each other, and the suspension then emerges from the chamber.
  • Alcohol used to prepare the pre-suspension is at least partially alcohol, i. E. the organic phase which is obtained after condensation of the vapor, phase separation of the condensate and collecting the organic phase of the condensate passed through a column in the lower region of the column.
  • fresh alcohol can be used, e.g. 4-50% of the total amount of the alcohol, preferably 5-40% of the total amount of the alcohol.
  • the dispersing vessel is usually made of metallic materials, whereby stainless steel is preferred.
  • the dispersing boiler can be connected to the reactor on the gas side.
  • the pre-suspension is passed into the reactor.
  • all pumping pumps known to the person skilled in the art can be used as pumps, which, taking into account the properties of the pre-suspension to be conveyed, are considered suitable for this purpose.
  • a delivery pump is a silk, piston, screw, impeller or peristaltic pump used.
  • the addition of the pre-suspension in the reactor can be carried out in portions or continuously.
  • the metered addition is carried out continuously.
  • the pre-suspension can in principle be metered in at any point of the reactor, but preferably the pre-suspension is added in the upper region of the reactor, in particular above the liquid level in the reactor. In this way, reverse flow against the metering direction can be largely prevented.
  • the reactor may be any reactor suitable for carrying out chemical reactions in the liquid phase.
  • reactors are not backmixed reactors, such as tubular reactors or internals
  • Residence time vessel but preferably backmixed reactors, such as stirred tank,
  • Loop reactors, jet loop reactors or jet nozzle reactors suitable.
  • reactors can be combined in a multi-stage apparatus.
  • Such reactors are, for example, loop reactors with built-in sieve trays, cascaded vessels, tube reactors with intermediate feed or stirred columns.
  • Roughkesselreaktoren usually consist of metallic materials, with stainless steel is preferred.
  • the presuspension and the esterification catalyst are brought into contact to obtain a reaction suspension.
  • i) the pre-suspension is passed into the unfilled reactor, ii) the boiling suspension is boiled and iii) the esterification catalyst is added.
  • the order of steps ii) and iii) may be reversed.
  • the esterification catalyst is introduced into the reactor in a partial amount of alcohol, for example 4-50% of the total amount of the alcohol, preferably 5-40%.
  • the catalyst / alcohol mixture can first be heated to boiling and then the addition of the pre-suspension can be started. Alternatively, the presuspension is added to the catalyst / alcohol mixture and then heated.
  • the heating of the catalyst / alcohol mixture and the addition of the pre-suspension can be carried out in parallel.
  • the metered addition of the catalyst in the heated to boiling in the reactor pre-suspension is carried out in parallel.
  • Particular preference is given to a process in which a mixture of alcohol and catalyst at a temperature which is at or above the boiling point of the alcohol and at or above the minimum reaction temperature is present in the reactor and the presuspension is metered into the reactor.
  • the reaction minimum temperature is considered to be the temperature at which the reaction between terephthalic acid and alcohol proceeds spontaneously in the presence of the catalyst and at the reaction pressure.
  • the reaction rate and thus the rate of formation of reaction water can be controlled by the rate at which the pre-suspension is added. In this way, undesirable foaming of the reaction mixture, e.g. By slowing down the supply of the pre-suspension can be avoided without the energy input must be throttled into the reaction mixture.
  • the control of the reaction rate over the rate of addition of the pre-suspension allows a fast response, while a control over the energy input allows only a delayed response.
  • the mixture of alcohol and catalyst introduced in the reactor is suitably prepared by initially introducing alcohol, heating it to boiling and mixing it with the catalyst. It is preferred in the interest of a short set-up time that the heating of the alcohol introduced takes place with maximum energy input.
  • the pre-suspension has, for example, a concentration of 1 to 50 g, preferably 10 to 40 g, of terephthalic acid per 100 g of pre-suspension.
  • the pre-suspension is suitably metered at a rate of from 0.1 to 0.8 starting volumes per hour, the starting volume being considered to be the volume of the mixture of alcohol and catalyst introduced in the reactor.
  • the pre-suspension is metered into the reactor at a temperature which is above the ambient temperature, preferably at a temperature of 50 to 150 ° C., for example 100 to 130 ° C.
  • the back alcohol used according to the invention for the preparation of the pre-suspension is obtained at a temperature which is sufficient to heat the pre-suspension to, for example, 50 to 150.degree.
  • the initially prepared presuspension may optionally be heated externally.
  • the reaction suspension in the reactor has a temperature near the boiling point of the reaction mixture, for example, a temperature of 150 ° C to 250 ° C, preferably 185 ° C to 220 ° C.
  • the boiling point of the reaction suspension is dependent on the ratio of terephthalic acid to alcohol and increases during the course of the reaction.
  • the heating of the initially introduced alcohol, the pre-suspension and / or a catalyst / alcohol mixture in the reactor can be carried out in any desired manner, for example by using a heating medium in a jacketed vessel, by a heating medium through which flows conduits or channels, which are thermally conductively connected to the reactor wall by electroheating, by pumping the mixture presented over an external heat exchanger or by an internal heating coil, which is heated using a heating medium, such as steam or oil.
  • a heating medium such as steam or oil.
  • welded half-snakes i. shell-shaped pipe segments placed around the reactor and welded to the reactor wall are used for heating.
  • the heat input into the reaction system can take place.
  • the reaction suspension is heated by pumping it over a heat exchanger located outside the reactor.
  • heat exchangers for example plate or shell-and-tube heat exchangers, or combinations thereof, come into consideration as heat exchangers.
  • the reaction suspension is withdrawn from the reactor using a pump and passed through the heat exchanger.
  • the heat exchanger is connected in a fluid-conducting manner with the reactor for the return of the heated reaction suspension into the reactor.
  • the reaction suspension may in principle be withdrawn at different positions of the reactor below the liquid level of the reaction suspension, but preferably the reaction suspension is withdrawn at the lowest point of the reactor.
  • the reactor is designed so that the reaction suspension at the geodesically low is withdrawn th point of the reactor and no dead spaces, due to locally deepest te bodies present in the reactor.
  • the pump for withdrawing the reaction suspension can in principle be arranged at different positions outside the reactor. For example, the pump is arranged at the geodetically lowest point of the reactor, pump and connecting lines existing circuit.
  • pumps which can be used for carrying out the method according to the invention, taking into account the properties of the reaction suspension to be conveyed.
  • a centrifugal, piston, screw, impeller or peristaltic pump can be used as a feed pump.
  • a feed pump can be used as a feed pump.
  • an axial or radial centrifugal pump is preferred.
  • the return of the reaction suspension in the reactor can in principle be carried out at any position of the reactor, but expediently the recirculation takes place in the upper region of the reactor, for example at the level of the liquid level of the reaction suspension or in the range from the height of the liquid level of the reactor suspension to 30% below ,
  • the volumetric flow which is conducted through the heating device is selected, for example, such that a circulation of the complete reactor contents takes place over a period of 1 to 60 minutes, preferably 1 to 10 minutes.
  • the constant circulation of the reactor contents ensures effective mixing of the reaction suspension.
  • the mixing of the reaction suspension can be assisted by the introduction of an inert gas into the reactor, in particular at the lowest point of the reactor, and / or a stream of the reaction suspension.
  • the metered addition of the inert gas contributes to the prevention of sedimentation of terephthalic acid at the bottom of the reactor or in pipelines, particularly in the event of malfunction of the pump for withdrawing the reaction suspension, for example in the event of a pump failure.
  • the dosing of the inert gas takes place on the suction side of the pump.
  • the metering can take place simultaneously on the pressure side of the pump or on the suction side and pressure side. This makes it possible to maintain the circulation through the heat exchanger even if the pump fails.
  • Inert gases are all gases which, under the reaction conditions, have no reactivity with the constituents of the reaction suspension, in particular nitrogen or argon.
  • the inert gas is metered into the reactor in an amount of 0.01 to 5 volume units of the inert gas per unit volume of the reaction suspension per hour.
  • the metering in of the inert gas can also be used to circulate the reactor contents.
  • the mixing can be assisted by the use of a stirrer.
  • an alcohol-water mixture is distilled off with the vapor, the vapor is at least partially condensed, the condensate is separated into an aqueous phase and an organic phase and the organic phase is passed through a column in which the organic phase is at least a portion of the vapor opposite, the organic phase collected in the lower part of the column and passed at least partially into the dispersing.
  • the organic phase collected in the lower part of the column can be temporarily stored in a collection container and directed from the collection container into the dispersing vessel for the same batch or a subsequent batch.
  • suitable capacitors can be used for condensation or partial condensation of the vapor. These can be cooled with any cooling media.
  • Capacitors with air cooling and / or water cooling are preferred, with air cooling being particularly preferred.
  • the resulting condensate is subjected to phase separation into an aqueous phase and an organic phase.
  • the condensate is usually passed into a phase separator (decanter), where it decays by mechanical settling into two phases, which can be withdrawn separately.
  • the aqueous phase is separated off and, if appropriate after work-up, can be discarded or used as stripping water in the after-treatment of the ester.
  • the organic phase is passed through a column (so-called re-alcohol column), in which the recycled organic phase is at least a portion of the vapor.
  • the back alcohol column can be, for example, a tray column, packed column or packed column. A low number of separation stages is generally sufficient. Suitable is z.
  • B. a column with 2 to 10 theoretical plates.
  • the column is placed at the top of the reactor, that is connected directly to the reactor.
  • the organic phase is introduced at the top or in the top of the back alcohol column.
  • the effluent condensate of the back alcohol column is collected.
  • a collecting bottom is suitably attached in the lower region of the column, for. B.
  • the collection floor has, for example, an incline to the inside and a central extraction cup and drainage nozzle. From the collection bottom of the column is the collected condensate passed as mulchalkohol in the dispersing.
  • the back alcohol can also be temporarily stored in a collecting tank. Thus, fluctuations between the attack of the back alcohol and the need for alcohol to produce the pre-suspension can be compensated.
  • the back alcohol is then passed from the sump into the dispersion kettle, when fresh alcohol is needed in the dispersing kettle to make the presuspension.
  • the derivation of the remindalkohols can be done by gravity or using a conveyor, such as a rotary, piston, screw, impeller or peristaltic pump.
  • the recycling of the organic phase via the back alcohol column has the advantage that the recycled organic phase is depleted of traces of water which have remained in the organic phase after the phase separation or are dissolved in the organic phase according to their thermodynamic solubility.
  • the water content in the recycled organic phase which is at least partially conducted into the dispersing kettle, is less than the maximum solubility of water in the alcohol, preferably less than 3% by weight, in particular less than 0.5% by weight. %.
  • the recycled alcohol passed into the dispersing kettle is available for the suspension of terephthalic acid in the dispersing kettle.
  • the dosage of terephthalic acid as a pre-suspension can be distributed over the duration of the reaction. This eliminates the need to handle concentrated suspensions.
  • This has the advantage that the suspension supplied to the reactor has a low solids content and thus can be well promoted. Furthermore, by using back alcohol, the solids concentration in the reactor is also low, so that the reaction volume can be optimally utilized. Another advantage is that less precipitation problems occur due to sedimentation.
  • linear, branched or cyclic aliphatic alcohols having 4 to 18 C atoms, in particular 8 to 14 C atoms, or aromatic alcohols.
  • the alcohols are monools and / or polyols and may be tertiary, secondary or primary.
  • the alcohols used can come from different sources. Suitable starting materials are, for example, fatty alcohols, alcohols from the Alfol process or alcohols or alcohol mixtures which are obtained by hydrogenation of saturated or unsaturated alcohols. aldehydes, especially those whose synthesis includes a hydroformylation step.
  • Aliphatic alcohols which are used in the process according to the invention are, for example, n-butanol, isobutanol, pentanols, hexanols, heptanols, octanols, such as n-octanol, 2-ethylhexanol, nonanols, decyl alcohols or tridecanols prepared by hydroformylation or aldol condensation and subsequent hydrogenation.
  • the alcohols can be used as a pure compound, as a mixture of isomeric compounds or as a mixture of compounds with a different carbon number.
  • An example of such an alcohol mixture is a C 9 / C 11 alcohol mixture.
  • Aromatic alcohols which can be used in the process according to the invention are, for example, phenol, benzyl alcohol, 1-naphthol, 2-naphthol, 1, 2-dihydroxybenzene, 1, 3-dihydroxybenzene, 1, 4-dihydroxybenzene, 1, 4-naphthohydroquinone , 2,4,6-trinitrophenol, primary phenylethyl alcohol, secondary phenylethyl alcohol, phenylpropyl alcohol, o-tolyl alcohol, p-tolyl alcohol, cumene alcohol, p-nitrophenol, m-, o- or p-alkylphenol, for example m-, o- or p-methylphenol or m-, o- or p-ethylphenol, m-, o- or p-halophenol, e.g.
  • Polyols which can be used in the process according to the invention are, for example, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5 Pentanediol, 1, 6-hexanediol, 1, 10-decanediol, diethylene glycol, 2,2,4-trimethylpentane-1, 5-diol, 2,2-dimethylpropane-1,3-diol, 1,4-dimethylolcyclohexane, 1, 6-dimethylolcyclohexane, glycerol, trimethylolpropane, erythritol, pentaerythritol and sorbitol.
  • Particularly preferred alcohols are 2-ethylhexanol, 2-propylheptanol, isononanol isomer mixtures, decanol isomer mixtures and C 9 / C 11 -alcohol mixtures.
  • the alcohol to be converted which serves as an entraining agent, can be used in stoichiometric excess.
  • the amount of alcohol used is chosen so that at theoretical full conversion of terephthalic acid is a mixture of ester and unreacted alcohol containing 10 to 35 wt .-% alcohol.
  • the esterification according to the invention is carried out in the presence of an esterification catalyst.
  • the esterification catalyst is soluble in the alcohol.
  • the esterification catalyst is among Lewis acids such as alcoholates, carboxylates and chelate compounds of titanium, zirconium, hafnium, tin, aluminum and zinc; Boron trifluoride, boron trifluoride etherates; Mineral acids, such as sulfuric acid, phosphoric acid; Sulfonic acids, such as methanesulfonic acid and toluenesulfonic acid, and ionic fluids.
  • Lewis acids such as alcoholates, carboxylates and chelate compounds of titanium, zirconium, hafnium, tin, aluminum and zinc
  • Boron trifluoride such as sulfuric acid, phosphoric acid
  • Sulfonic acids such as methanesulfonic acid and toluenesulfonic acid, and ionic fluids.
  • the esterification catalyst is selected from alkoxides, carboxylates and chelates of titanium, zirconium, hafnium, tin, aluminum and zinc.
  • Tetraalkyl titanates such as tetramethyl titanate, tetraethyl titanate, tetra n-propyl titanate, tetra-isopropyl titanate, tetra-n-butyl titanate, tetra-isobutyl titanate, tetra-sec-butyl titanate, tetraoctyl titanate, tetra (2-ethylhexyl) titanate; Dialkyl titanates ((RO) 2TiO, where R is, for example, iso-propyl, n-butyl, iso-butyl), such as isopropyl n-butyl titanate; Titanium acetylacetonate chelates such as diisopropoxy bis (acet
  • Suitable ionic liquids are z.
  • the catalyst concentration depends on the type of catalyst. In the case of the titanium compounds which are preferably used, this is from 0.001 to 1.0 mol%, based on the amount of terephthalic acid, in particular from 0.01 to 0.2 mol%.
  • the reaction temperatures are between 100 ° C and 250 ° C.
  • the optimum temperatures depend on the starting materials, reaction progress and the catalyst concentration. They can easily be determined by experiment for each individual case. Higher temperatures increase the reaction rates and promote side reactions, such as olefin formation or formation of colored by-products. It is necessary to remove the water of reaction that the alcohol can distill off from the reaction mixture.
  • the desired temperature or the desired temperature range can be adjusted by the pressure in the reactor. In the case of low-boiling alcohols, therefore, the reaction can be carried out under reduced pressure and with higher-boiling alcohols under reduced pressure. For example, in the reaction of terephthalic acid with 2-ethylhexanol in a temperature range of 180 ° C to 220 ° C in the pressure range of 300 mbar to 2 bar worked.
  • the reaction pressure is reduced when a predetermined terephthalic acid conversion is reached.
  • the alcohol in the reactor evaporates substantially faster than at the outlet pressure.
  • the alcohol is not passed into the dispersion vessel but into a collecting tank for alcohol. In this way, the alcohol concentration in the reactor is reduced and the achievement of substantially complete conversion possible.
  • the reaction is carried out up to the limit conversion at 900 to 1100 mbar and then reduces the pressure to below 900 mbar, for example 10 to 600 mbar, 100 to 550 mbar, in particular 200 to 500 mbar.
  • the marginal revenue is usually large Above 90%, in particular greater than 95%, for example about 97%.
  • the pressure at the beginning of the reaction until reaching the limit conversion corresponds to the ambient pressure, for example 1 atm.
  • the pressure reduction is preferably carried out stepwise. In particular, the pressure is reduced in steps of 20 to 50 mbar until the desired pressure level is reached.
  • the stepwise reduction in pressure has the advantage that foaming of the reaction mixture, which is to be expected if the pressure is reduced too rapidly, is prevented.
  • the first pressure stage is preferably in the range 450 mbar to 550 mbar, e.g. about 500 mbar, the second in the range 150 to 350 mbar, e.g. about 300 bar.
  • the reaction of terephthalic acid with 2-ethylhexanol to about 97% conversion occurs at 1 atm; from 97% conversion, the pressure is gradually reduced to about 500 mbar, so that complete conversion is achieved.
  • a small reduction of the temperature in the reactor can take place.
  • a further reduction in pressure to about 300 mbar optionally combined with an increase in the reactor temperature and / or an opposing inert gas stream, the stripping of the reaction mixture can take place.
  • the process is carried out for 5 to 20% of the reaction time, in particular 8 to 12% of the reaction time, at a pressure of less than 900 mbar.
  • the reaction is carried out for about 10% of the reaction time at a pressure of 250 to 550 mbar.
  • reactor and the dispersion vessel are operated at essentially the same pressure, in particular approximately ambient pressure or a slight negative pressure, such as about 900 mbar.
  • reactor and dispersing vessel can also be operated at different pressures.
  • the process according to the invention is preferably carried out until the terephthalic acid has essentially reacted completely.
  • the determination of the conversion can be made by determining the acid number of the reaction suspension.
  • the acid number is determined by neutralization of a sample of the reaction suspension with tetrabutylammonium hydroxide.
  • the mass of tetrabutylammonium hydroxide consumed can be determined via the mass of tetrabutylammonium hydroxide consumed in the neutralization, and the substance quantity of the spent tetrabutylammonium hydroxide can be determined via stoichiometric considerations. amount of free acid groups unreacted terephthalic acid.
  • the conversion can thus be determined. Additional possibilities for determining the conversion are HPLC measurements and the measurement of the turbidity of the reaction suspension. In the process according to the invention, preferably a conversion greater than 99% is achieved.
  • reaction mixture which consists essentially of the desired ester and excess alcohol, in addition to the catalyst and / or its derivatives, small amounts of ester carboxylic acid (s) and / or unreacted carboxylic acid.
  • the esterification catalyst is deactivated by the addition of an aqueous base and precipitated. At the same time, the acid or partial ester of the acid not reacted in the esterification reaction is converted into salts.
  • aqueous base may be effected in any suitable manner. It preferably takes place below the liquid surface of the crude ester.
  • z. As lances or nozzles, which are provided on a container bottom or the container wall. The mixture is then mixed thoroughly, z. B. by means of a stirrer or a circulating pump.
  • the amount of aqueous base added is such that it is sufficient to completely neutralize the acid components of the crude ester. In practice, a more or less large excess of base is used.
  • the total amount of the acidic components of the crude ester is conveniently measured by the acid number (in mg KOH / g). From 100 to 300% neutralization equivalents are preferably added to the aqueous base, based on the acid number of the crude ester, in particular from 130 to 220%.
  • neutralization equivalent is meant the amount of base capable of binding the same number of protons as 1 mg of KOH. In other words, a base excess of up to 400%, preferably 100 to 300%, is used.
  • the reactor is actively cooled before addition and also by the addition of the aqueous base, for example to a temperature between 100 and 150 ° C, for example 135 to 145 ° C.
  • the aqueous base is also cooled prior to addition, for Example at a temperature of 10 to 40 ° C.
  • the reactor can be additionally cooled. This is particularly useful to reduce or possibly completely prevent the evaporation of water upon the addition of the aqueous base.
  • Suitable aqueous bases are solutions of hydroxides, carbonates, hydrogen carbonates of alkali metals and alkaline earth metals.
  • Aqueous alkali metal hydroxide solutions are generally preferred.
  • Aqueous sodium hydroxide solution is particularly preferred because of its ready availability.
  • the concentration of the aqueous base is not critical per se, but the use of concentrated alkali solutions at the point of introduction of the base may result in the hydrolysis of the esters.
  • the concentration of the aqueous base should not be too low, since the water introduced with the aqueous base must be removed again in the subsequent step. Therefore, aqueous bases of moderate to low concentration are preferred, e.g. B. those of a concentration of 0.5 to 25 wt .-%, in particular 1 to 10 wt .-%.
  • Aqueous sodium hydroxide solution with a concentration of 1 to 5 wt .-% is particularly preferred.
  • the precipitated solid which consists essentially of catalyst decomposition products and salts of unreacted acid or partial esters of polybasic acids, is present in finely divided, difficult-to-filter form.
  • the fine particles are agglomerated into larger, easily separable particles.
  • the liquid phase is added to form a water-in-oil emulsion with water.
  • the water is distributed as a disperse phase in the form of fine droplets in the liquid organic phase.
  • the fine particulates migrate to the interface between water droplets and surrounding organic phase.
  • the fine particles agglomerate and form coarse, easily separable particles.
  • the added amount of water In order for its own water phase to form, the added amount of water must be greater than the solubility of water in the organic phase corresponds.
  • the water solubility in the organic phase depends inter alia on the content of unreacted alcohol, since the alcohol acts as a solubilizer. The higher the alcohol content, the more water must be added to form the emulsion.
  • At residual alcohol contents of 1 to 10 wt .-% are generally from 10 to 80 g of water, preferably 30 to 50 g, based on 1 kg of crude ester, in particular about 5 wt .-% water suitable.
  • the water phase is broken up into fine droplets using a suitable stirrer or homogenizer or by pumping the emulsion over using a circulation pump.
  • the water droplets produced preferably have an average droplet size of less than 1000 ⁇ m.
  • stirrers with high specific stirring power for example, disk stirrers are suitable.
  • a mixing nozzle in which water is added directly into the crude ester stream via a dispersing valve.
  • the emulsion is conveniently carried out at about atmospheric pressure.
  • the water is distilled off again from the emulsion thus produced.
  • the solid is in a good filterable form; it does not precipitate fines in the filtration.
  • suitable filters such as chamber filter presses, band filter, candle filter or plate filter. Plate filters with centrifugal cake discharge are particularly suitable for continuous process control. The separated solid is discarded.
  • the ester may be subjected to various post-treatments, such as steam stripping or the like.
  • a further post-treatment step may additionally be carried out, e.g. a filtration or treatment with activated charcoal in which the product after steam stripping is treated with activated charcoal (e.g., 0.1 to 10% by weight) at a temperature of for example 20 to 100 ° C and for a period of e.g. Is stirred for 1 to 120 min.
  • the activated carbon treated product is then usually subjected to a filtration step.
  • the invention further relates to a device for the preparation of terephthalic acid diesters by the process described above, comprising a dispersing vessel, which is liquid-conductively connected to a reactor, wherein the reactor contents can be pumped via a heat exchanger, a column, which is connected to the reactor Brüden facedd, and a condenser, which is connected to the column broth-conducting and with a phase separator liquid-conducting, wherein the phase separator with the column is fluidly connected to direct collected organic phase in the column,
  • a collecting tank which is liquid-conducting connected to the collection tray and the dispersing vessel.
  • FIG. 1 shows a system suitable for carrying out the method according to the invention.
  • terephthalic acid is metered from the reservoir 10 into a dispersing vessel 7 and mixed with the aid of a stirrer 11 in alcohol for the presuspension.
  • alcohol is metered from the reservoir 9 via the collecting tank 13 and the pump 14 into the dispersing vessel 7;
  • alcohol is passed from the collecting bottom 12 of the column 6 into the collecting tank 13.
  • the alcohol is withdrawn by means of the pump 14 and passed as required into the dispersing vessel 7.
  • the pre-suspension is passed by means of a pump 8 in the upper region of the reactor 1.
  • In the reactor 1 are another subset of the alcohol and the esterification catalyst.
  • the reaction suspension is withdrawn from the reactor using a pump 2 mounted outside the reactor and passed through a heat exchanger 3 located outside the reactor.
  • the reaction suspension heated in the heat exchanger 3 is returned to the upper area of the reactor 1 again.
  • the vapor passes through the column 6 and is at least partially condensed in the condenser 4.
  • the condensate is separated into an aqueous and an organic phase.
  • the aqueous phase is discarded, the organic phase is passed over the column 6, the condensate that runs off is collected on a collecting tray 12 and passed into the dispersing kettle 7.
  • the following example illustrates the preparation of dioctyl terephthalate (DOTP) by reacting terephthalic acid with 2-ethylhexanol in a miniplant plant.
  • An embodiment of the process according to the invention is obtained if the plant is supplemented by a dispersing kettle in which the terephthalic acid is slurried in alcohol, and the terephthalic acid suspension is passed from the dispersing vessel into the reactor over a period of time.
  • the alcohol used is sert organic phase of a previous experiment, which is collected and discharged at the bottom of the distillation column on a collecting tray.
  • the vapors obtained at the top of the distillation column were condensed and transferred to the phase separation vessel, wherein a water-rich phase deposited at the bottom of the vessel, which was continuously transferred via a siphon into a collecting vessel and thus removed from the system, and a water-saturated organic phase flowed out of the upper area of the separation vessel.
  • the organic phase thus obtained was recycled by means of a pump to the top of the distillation column and dewatered by rectification on the distillation column.
  • the dewatered organic phase ran from the bottom of the distillation column back into the reactor.
  • the acid value of the crude product thus obtained (-95% DOTP, -5% 2-ethylhexanol) was determined by means of automatic titration (0.07 mg KOH / g) and a 2.0% by weight solution of NaOH in water (8.20 g, ie 200% excess based on the titration certain stoichiometrically necessary amount) with stirring (250 rpm) at 100 ° C under nitrogen atmosphere. The resulting solution was stirred for 15 minutes and the water contained was removed in vacuo. Subsequently, a further amount of water (54 g) at 100 ° C was added and the emulsion obtained under nitrogen atmosphere for 20 min.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

La présente invention concerne un procédé pour la préparation d'un diester d'acide téréphtalique par conversion de l'acide téréphtalique avec au moins un alcool, consistant à suspendre l'acide téréphtalique dans une cuve de dispersion dans l'alcool, à amener la pré-suspension provenant de la cuve de dispersion dans un réacteur et à la faire réagir en présence d'un catalyseur d'estérification, et à distiller l'eau réactionnelle sous forme d'azéotrope alcool - eau avec les vapeurs, à condenser au moins partiellement les vapeurs, à séparer le condensat en une phase aqueuse et une phase organique et à conduire la phase organique sur une colonne, dans laquelle on amène à la phase organique au moins une partie des vapeurs, à récupérer la phase organique dans le bas de colonne et à la conduire au moins partiellement dans la cuve de dispersion.
EP15766174.5A 2014-09-24 2015-09-21 Procédé de préparation de diesters d'acide téréphtalique comportant un enrichissement par recyclage de l'alcool Withdrawn EP3197860A1 (fr)

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EP14186137 2014-09-24
EP15153483 2015-02-02
PCT/EP2015/071578 WO2016046120A1 (fr) 2014-09-24 2015-09-21 Procédé de préparation de diesters d'acide téréphtalique comportant un enrichissement par recyclage de l'alcool

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BR (1) BR112017005850A2 (fr)
CA (1) CA2962164A1 (fr)
MX (1) MX2017003926A (fr)
RU (1) RU2665579C1 (fr)
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CN110650941A (zh) * 2017-05-19 2020-01-03 沙特基础全球技术有限公司 生产增塑剂并降低能耗的方法
PL234516B1 (pl) * 2017-11-24 2020-03-31 Grupa Azoty Zakl Azotowe Kedzierzyn Spolka Akcyjna Sposób otrzymywania tereftalanów
TWI691481B (zh) * 2018-01-24 2020-04-21 南亞塑膠工業股份有限公司 一種提升對苯二甲酸酯可塑劑反應效能之方法
CN108752202B (zh) * 2018-07-04 2021-08-10 南通百川新材料有限公司 一种连续酯化法制备偏苯三甲酸三酯的方法
KR102489171B1 (ko) * 2019-07-04 2023-01-18 주식회사 엘지화학 디에스터계 물질의 제조 유닛 및 이를 포함하는 디에스터계 물질의 제조 시스템
KR102489173B1 (ko) * 2019-07-04 2023-01-18 주식회사 엘지화학 열교환 시스템 및 이를 포함하는 디에스터계 조성물 제조 시스템
KR102489172B1 (ko) * 2019-07-04 2023-01-18 주식회사 엘지화학 디에스터계 물질의 제조 유닛 및 이를 포함하는 디에스터계 물질의 제조 시스템
CN111077145A (zh) * 2019-12-26 2020-04-28 沈阳化工研究院有限公司 连续生产中芳香胺重氮化反应转化率测定和/或控制方法
WO2021246809A1 (fr) * 2020-06-05 2021-12-09 주식회사 엘지화학 Procédé de commande de réaction dans un procédé de fabrication en continu d'une composition à base de diester
TWI792452B (zh) * 2021-07-27 2023-02-11 長春人造樹脂廠股份有限公司 對苯二甲酸二（2-乙基己基）酯組合物
CN113769427B (zh) * 2021-09-26 2024-05-28 上海交通大学 一种联产二甲基碳酸酯和二元醇的系统及方法

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CN107074721A (zh) 2017-08-18
US10266477B2 (en) 2019-04-23
CA2962164A1 (fr) 2016-03-31
CN107074721B (zh) 2021-01-08
TW201612152A (en) 2016-04-01
MX2017003926A (es) 2017-06-30
RU2665579C1 (ru) 2018-08-31
US20170297998A1 (en) 2017-10-19
WO2016046120A1 (fr) 2016-03-31
BR112017005850A2 (pt) 2018-02-06

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