EP1915359A1 - Procede integre de production de trioxane a partir de formaldehyde - Google Patents

Procede integre de production de trioxane a partir de formaldehyde

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Publication number
EP1915359A1
EP1915359A1 EP06792714A EP06792714A EP1915359A1 EP 1915359 A1 EP1915359 A1 EP 1915359A1 EP 06792714 A EP06792714 A EP 06792714A EP 06792714 A EP06792714 A EP 06792714A EP 1915359 A1 EP1915359 A1 EP 1915359A1
Authority
EP
European Patent Office
Prior art keywords
stream
formaldehyde
trioxane
water
distillation column
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Withdrawn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
EP06792714A
Other languages
German (de)
English (en)
Inventor
Neven Lang
Eckhard Stroefer
Achim Stammer
Thorsten Friese
Markus Siegert
Hans Hasse
Thomas GRÜTZNER
Sergej Blagov
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 EP1915359A1 publication Critical patent/EP1915359A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D323/00—Heterocyclic compounds containing more than two oxygen atoms as the only ring hetero atoms
    • C07D323/04—Six-membered rings
    • C07D323/06—Trioxane
    • 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 invention relates to an integrated process for the preparation of trioxane from formaldehyde.
  • Trioxane is generally prepared by reactive distillation of aqueous formaldehyde solution in the presence of acidic catalysts. A mixture containing trioxane, formaldehyde and water is obtained as distillate. From this mixture, the trioxane is then separated by extraction with halogenated hydrocarbons, such as methylene chloride or 1,2-dichloroethane, or other, water-immiscible solvents.
  • halogenated hydrocarbons such as methylene chloride or 1,2-dichloroethane, or other, water-immiscible solvents.
  • DE-A 1 668 867 describes a process for the separation of trioxane from mixtures containing water, formaldehyde and trioxane by extraction with an organic solvent.
  • an extraction section consisting of two sections is fed at one end with an organic extractant for trioxane which is virtually immiscible with water, and at the other end with water.
  • the distillate to be separated from the trioxane synthesis is fed.
  • an aqueous formaldehyde solution is obtained on the side of the solvent feed and a virtually formaldehyde-free solution of trioxane in the solvent is obtained on the side of the water feed.
  • a disadvantage of this procedure is the accumulation of extractant, which must be purified.
  • Some of the extractants used are hazardous substances (T or T + substances within the meaning of the German Hazardous Substances Ordinance), the handling of which requires special precautions.
  • DE-A 197 32 291 describes a process for the separation of trioxane from an aqueous mixture consisting essentially of trioxane, water and formaldehyde, in which trioxane is removed from the mixture by pervaporation and the trioxane-enriched permeate by rectification in pure trioxane on the one hand and an azeotropic mixture of trioxane, water and formaldehyde on the other hand separates.
  • an aqueous mixture consisting of 40% by weight of trioxane, 40% by weight of water and 20% by weight of formaldehyde in a first distillation column under normal pressure is mixed into a water / formaldehyde mixture and into an azeotropic trioxane / Separated water / formaldehyde mixture.
  • the azeotropic mixture is passed into a pervaporation unit, which has a membrane made of polydimethylsiloxane with a contains hydrophobic zeolites.
  • the trioxane-enriched mixture is separated in a second distillation column under normal pressure into trioxane and again into an azeotropic mixture of trioxane, water and formaldehyde. This azeotrope mixture is returned before the pervaporation step.
  • the object of the invention is to provide an alternative process for the preparation of trioxane from aqueous formaldehyde solution to obtain pure trioxane.
  • it is an object to provide a process which avoids the performance of extraction steps or pervaporation steps to obtain pure trioxane.
  • Trioxane is reacted, wherein a trioxane, water and formaldehyde-containing product stream A2 is included;
  • the stream A2 is fed to a first distillation column and distilled at a pressure in the range of 0.1 to 2.5 bar to obtain a trioxane-enriched stream B1 and the stream B2 consisting essentially of water and formaldehyde;
  • trioxane, formaldehyde and water form a ternary azeotrope which, at a pressure of 1 bar, has the composition 69% by weight of trioxane, 5% by weight of formaldehyde and 26% by weight of water.
  • the ternary azeotrope is separated by a pressure swing distillation by carrying out a first and a second distillation stage at different pressures. In a first distillation stage, which is operated at a lower pressure, the starting mixture is separated into a trioxane-rich trioxane / water / formaldehyde mixture with low formaldehyde content on the one hand and a substantially trioxane-free formaldehyde / water mixture on the other hand.
  • the trioxane-rich trioxane / water / formaldehyde mixture is then separated in a second distillation stage, which is carried out at high pressure, into a trioxane-rich trioxane / water / formaldehyde mixture on the one hand and pure trioxane on the other.
  • the trioxane-rich trioxane / water / formaldehyde mixture is fed to a third distillation stage, which is preferably operated at the same pressure as the first distillation stage.
  • a substantially trioxane-free water / formaldehyde mixture and a trioxane / water / formaldehyde mixture are obtained.
  • the trioxane / water / formaldehyde mixture is returned to the second distillation stage. This ensures that essentially all trioxane produced in the synthesis is obtained as a valuable product.
  • each distillation stage comprises a distillation column.
  • distillation column any distillation columns, such as packing or tray columns are suitable.
  • the distillation columns can contain any internals, packings or packed beds.
  • all pressure data refer to the pressure at the top of the relevant column.
  • a stream A1 containing water and formaldehyde and a recycle stream B2 consisting essentially of water and formaldehyde are fed to a trioxane synthesis reactor and allowed to react, yielding a product stream A2 comprising trioxane, water and formaldehyde.
  • the reaction is preferably carried out under acidic conditions.
  • the supply of the streams A1 and B2 can be carried out separately. However, it is also possible to see the streams A1 and B2 before being fed to the trioxane synthesis reactor.
  • the stream A1 contains from 50 to 85% by weight of formaldehyde and from 15 to 50% by weight of water.
  • the ratio of the streams A1 and B2 is preferably selected such that a total of from 15 to 70% by weight of water and from 30 to 85% by weight of formaldehyde, particularly preferably from 20 to 63% by weight, is present in the trioxane synthesis reactor. Water and from 37 to 80 wt .-% formaldehyde are supplied.
  • the product stream A2 generally contains 35 to 84% by weight of formaldehyde, 15 to 45% by weight of water and 1 to 30% by weight of trioxane.
  • the water / formaldehyde mixture is the trioxane synthesis stage a) homogeneously acid in the presence or heterogeneous present catalysts such as ion exchange resins, zeolites, sulfuric acid and p-toluenesulfonic acid at a temperature of generally 70 converted to 130 0 C.
  • present catalysts such as ion exchange resins, zeolites, sulfuric acid and p-toluenesulfonic acid at a temperature of generally 70 converted to 130 0 C.
  • the product mixture of trioxane, formaldehyde and water is then applied as a vaporized vapor withdrawal stream of the reactive steam generator or as a top draw stream of the reactive distillation column.
  • the trioxane synthesis can also be carried out in a fixed bed or fluidized bed reactor on a heterogeneous catalyst, for. As an ion exchange resin or zeolite, are performed.
  • step b) subsequent to step a) the stream A2 is fed to a first distillation column and distilled at a pressure of 0.1 to 2.5 bar, preferably 0.4 to 1.5 bar, for example 1 bar in which a trioxane-enriched stream B1 and the stream B2 consisting essentially of water and formaldehyde are obtained.
  • the first distillation column preferably contains 2 to 50, more preferably 4 to 40 theoretical stages.
  • the stripping section of the first distillation column comprises at least 25% of the number of theoretical plates in the distillation column.
  • the reinforcing member comprises 50 to 90% of the theoretical stages of this distillation column.
  • the trioxane-enriched stream B1 generally contains from 20 to 60% by weight of trioxane, from 15 to 79% by weight of water and from 1 to 25% by weight of formaldehyde.
  • the trioxane-enriched stream B1 preferably comprises from 25 to 55% by weight of trioxane, from 25 to 70% by weight of water and from 5 to 20% by weight of formaldehyde.
  • Stream B2 generally contains from 51 to 85% by weight of formaldehyde, from 15 to 49% by weight of water and from 0 to 1% by weight of trioxane.
  • stream B2 contains less than 0.5% by weight of trioxane, more preferably less than 0.1% by weight of trioxane.
  • the stream A2 is fed to the first distillation column, preferably in the bottom or as side feed in the stripping section of the column.
  • the stream B1 is preferably taken from the first distillation column as top draw stream and stream B2 as bottom draw stream.
  • the stream B1 can also be taken off as a side draw stream below the top of the column.
  • the trioxane synthesis stage a) and the first distillation stage b) are carried out together as reactive distillation in a reaction column.
  • This can contain a catalyst fixed bed of a heterogeneous catalyst in the stripping section.
  • the reactive distillation can also be carried out in the presence of a homogeneous catalyst, wherein an acid catalyst is present together with the aqueous formaldehyde solution in the bottom of the column.
  • step c) following step b), the stream B1 enriched with trioxane and a recycle stream D1 containing water and formaldehyde are fed to a second distillation column and distilled at a pressure of 0.2 to 17.5 bar, wherein a product stream consisting essentially of pure trioxane C2 and a trioxane, water and formaldehyde-containing stream C1 are obtained.
  • the second distillation column generally comprises at least 2 theoretical stages, preferably 10 to 50 theoretical stages.
  • the stripping section of this distillation column comprises 25 to 90%, preferably 50 to 75% of the theoretical stages of this column.
  • the pressure in the second distillation column is at least 0.1 bar higher than in the first distillation column. In general, this pressure difference is 0.5 to 10 bar, preferably 1 to 7 bar.
  • the second distillation column is preferably operated at a pressure between 2 and 10 bar, more preferably at a pressure between 2 and 7 bar.
  • the product stream C2 generally contains 95 to 100 wt .-%, preferably 99 to 100 wt .-% of trioxane and 0 to 5 wt .-%, preferably 0 to 1 wt .-% water.
  • the content of water in the product stream is particularly preferably ⁇ 0.1%. It can even be ⁇ 0.01%.
  • the stream C1 contains, for example, 5 to 20% by weight of formaldehyde, 15 to 40% by weight of water and 40 to 70% by weight of trioxane.
  • the stream B1 is fed to the second distillation column as a first side feed and the stream D1 as a second side feed above the first side feed.
  • the streams B1 and D1 are mixed before they are fed to the column.
  • the feed is preferably carried out as a side feed.
  • the stream C1 is preferably taken from the second distillation column as a top draw stream and the product stream C2 as a bottom draw stream.
  • the ratio of the streams B1 and D1 to each other is preferably selected so that the second distillation step a total of 1 to 25 wt .-% formaldehyde, 5 to 69% by weight of water and 30 to 80 wt .-% of trioxane, preferably 3 to 20 wt % Of formaldehyde, 5 to 57% by weight of water and 40 to 75% by weight of trioxane.
  • step d) subsequent to step c) the stream C1 is fed to a third distillation column and distilled at a pressure in the range from 0.1 to 2.5 bar, the recycle stream D1 containing trioxane, water and formaldehyde and an im Substantially water and formaldehyde existing stream D2 can be obtained.
  • the pressure in the third distillation column is generally 0.1 to 15 bar, preferably 0.5 to 10 bar and in particular 1 to 7 bar lower than the pressure in the second distillation column.
  • the pressure in the third distillation column is in the range of 0.5 to 2.0 bar, more preferably in the range of 0.4 to 1, 5 bar, and corresponds to the pressure in the first distillation column.
  • the third distillation column generally comprises at least 2 theoretical stages, preferably 10 to 50 theoretical stages.
  • the stripping section of the third distillation column comprises 25 to 90%, preferably 50 to 75% of the theoretical stages of this column.
  • the stream D1 generally contains 50 to 80% by weight of trioxane, 1 to 20% by weight of formaldehyde and 5 to 49% by weight of water.
  • the stream D1 preferably comprises 55 to 75% by weight of trioxane, 3 to 15% by weight of formaldehyde and 10 to 42% by weight of water.
  • the stream D2 contains, for example, 0 to 1% by weight of trioxane, 10 to 50% by weight of formaldehyde and 60 to 90% by weight of water.
  • the stream D2 preferably contains 0 to 0.5% by weight of trioxane, 15 to 40% by weight of formaldehyde and 60 to 85% by weight of water.
  • the stream C1 is fed to the third distillation column as a side feed.
  • the stream D1 generally falls as a top draw stream and the stream D2 as a bottom draw stream or as a side draw stream in the stripping section of the column.
  • the method according to the invention additionally comprises the following steps:
  • a feed stream F1 containing water and formaldehyde is fed to a formaldehyde concentration unit, stream A1 is taken from the concentration unit as a formaldehyde-rich bottom draw stream, and a low-formaldehyde stream F2 is taken off as top or bottom draw stream;
  • the stream D2 and the stream F2 are fed to a fourth distillation column and distilled at a pressure in the range of 1 to 10 bar, wherein a water and formaldehyde-containing stream E1 and a stream consisting essentially of water E2 are obtained.
  • Step e) precedes step a) and step f) is followed by step d).
  • step f) following step d) the stream D2 and a stream F2 obtained in the formaldehyde concentration unit are fed to the fourth distillation column and distilled at a pressure in the range from 1 to 10 bar, a stream E1 containing water and formaldehyde and a stream E2 consisting essentially of water can be obtained.
  • the fourth distillation stage is preferably carried out at a pressure between 2 and 7 bar.
  • the fourth distillation column has at least 2 theoretical stages, preferably 10 to 50 theoretical stages.
  • the stripping section of this distillation column comprises 25 to 90%, preferably 30 to 75% of the theoretical stages of this column.
  • the stream E2 generally contains at least 90% by weight, preferably at least 95% by weight and particularly preferably at least 97% by weight of water.
  • the stream E1 generally contains 0 to 2% by weight of trioxane, 40 to 80% by weight of formaldehyde and 20 to 60% by weight of water, preferably stream E1 contains 0 to 1% by weight of trioxane, 45 to 65% by weight .-% formaldehyde and 34 to 55 wt .-% water.
  • the stream D2 of the fourth distillation column is fed as a side feed in the stripping section of the column.
  • the stream F2 is also supplied as a side feed. However, it is also possible to mix the streams D2 and F2 and feed them together as side feed to the fourth distillation column.
  • the stream E1 At the top of the fourth distillation column, the stream E1 generally accumulates, which in one embodiment is fed to the trioxane synthesis reactor. In a further embodiment, the stream E1 is added to the formaldehyde concentration stage.
  • the essentially water E2 stream is obtained as a bottom draw stream or as a side draw stream in the stripping section of the column.
  • low-boiling components which can be formed in the trioxane synthesis and the subsequent distillative separation are methyl formate, methylal, dimethoxydimethyl ether, trimethoxydimethyl ether, methanol, formic acid and further hemiacetals and acetals.
  • a further distillation stage lower boiler separation stage
  • the low-boiling components are preferably separated off via the top of the low-boiler separation column, which is preferably operated at a pressure of 1 to 3 bar.
  • the low boiler separation column has at least 5 theoretical stages, preferably 15 to 50 theoretical stages.
  • the stripping section of this column comprises from 25 to 90% of the theoretical stages of this column.
  • Stream B1 is fed as a side feed to this low boiler separation column and BT stream liberated from the low boilers is generally contained as a bottom draw stream. If the low boiler separation is carried out, the stream BT is supplied as stream B1 to the subsequent second distillation column. Likewise, this low-boiling column and the recycled Storm D1 can be supplied, if this stream contains low boilers.
  • the concentration e) of the feed stream F1 containing water and formaldehyde is generally carried out in a distillation column or in an evaporator.
  • the concentration is preferably carried out in an evaporator, more preferably in a continuous evaporator.
  • Suitable continuous evaporators are z.
  • the falling film Steamer is generally operated at a pressure of 50 to 200 mbar and a temperature of 40 to 75 ° C.
  • the concentration step e) can be carried out, for example, as described in DE-A 199 25 870.
  • the formaldehyde-rich stream A1 obtained in the concentration is generally taken off as the bottom draw stream, the low-formaldehyde stream F2 is taken off as top or bottom draw stream.
  • the feed stream F1 containing water and formaldehyde is preferably fed as side feed.
  • the pure trioxane obtained is preferably used for the preparation of polyoxymethylene (POM), polyoxymethylene derivatives such as polyoxymethylene dimethyl ether (POMDME) and diaminodiphenylmethane (MDA).
  • POM polyoxymethylene
  • POMDME polyoxymethylene dimethyl ether
  • MDA diaminodiphenylmethane
  • FIG. 1 shows a process flow diagram of a first variant of the method according to the invention
  • FIG. 2 shows a process flow diagram of a second variant of the method according to the invention.
  • FIG. 1 shows a first variant of the method according to the invention.
  • An aqueous formaldehyde solution 1 (stream F1) is added to a concentration unit 2.
  • the concentration unit 2 can be any distillation column, for. B. a tray column, packed column or packed column or a continuous evaporator, for. B. be a circulation evaporator, falling film evaporator, Wendelrohrverdampfer or thin film evaporator.
  • the concentration unit 2 is a falling-film evaporator.
  • a formaldehyde-rich bottom draw stream 3 (stream A1) and a low-formaldehyde aqueous vapor stream are obtained as the top draw stream 4 (stream F2).
  • the formaldehyde-rich bottom draw stream 3 is fed to a trioxane synthesis reactor 5.
  • trio xan synthesis reactor 5 the aqueous formaldehyde solution is converted to trioxane in the presence of an acidic homogeneous or heterogeneous catalyst present.
  • a stream 6 containing trioxane, formaldehyde and water (stream A2) is fed as side feed to a first distillation column 7.
  • the stream 6 is separated into a trioxane-enriched stream 8 (stream B1) which is taken from the first distillation column 7 as a top draw stream and a stream 9 (stream B2) consisting essentially of water and formaldehyde and obtained as a bottom draw ,
  • the stream 9 at the bottom (stream B2) is returned to the trioxane synthesis reactor 5.
  • the stream 8 (stream B1) obtained at the top of the first distillation column 7 is fed to a second distillation column 10.
  • the second distillation column 10 is supplied with a recycle stream 11 (stream D1) containing trioxane, water and formaldehyde at the top of a third distillation column 12.
  • the streams 8 and 11 fed to the second distillation column 10 are separated into a substantially trioxane-containing product stream 13 (stream C2) and a trioxane, water and formaldehyde-containing stream 14 (stream C1) withdrawn at the top of the second distillation column 10.
  • the stream 14 is fed via a side inlet of the third distillation column 12.
  • the third distillation column 12 there is a separation of the stream 14 in the trioxane, formaldehyde and water containing, incurred at the top recycle stream 11 (stream D1) and a substantially consisting of formaldehyde and water stream 15 (stream D2), at the bottom of the third Is withdrawn distillation column.
  • the stream 15 (stream D2) is fed as a side feed to the stripping section of a fourth distillation column 16.
  • the fourth distillation column 16 is supplied with the top exhaust stream 4 (stream F2) to the concentration unit 2 as a side feed at the top.
  • the fourth distillation column 16 is then a separation of the supplied streams 4, 15 in a substantially water-containing, obtained at the bottom of stream 17 (stream E2) and at the top of the fourth distillation column 16 resulting, formaldehyde and water-containing stream 18 (stream E1 ).
  • the stream 18, which is substantially free of trioxane, is fed to the concentration unit 2.
  • FIG. 2 shows a second variant of the method according to the invention.
  • the process illustrated in FIG. 2 differs from the variant shown in FIG. 1 in that the stream 18 (stream E1) obtained at the top of the fourth distillation column 16 is not passed into the concentration unit 2 but into the trioxane synthesis reactor 5 the formaldehyde-rich bottoms Ström 3 of the concentration unit 2 and obtained at the bottom of the first distillation column 7 stream 9 (stream B2) mixed before addition to the synthesis reactor 5 and not separately added to the synthesis reactor 5.
  • a concentration unit 2 designed as a falling-film evaporator is fed with an aqueous formaldehyde solution 1 of 37% by weight of formaldehyde and 63% by weight of water.
  • the falling-film evaporator is operated at a pressure of 100 mbar and a temperature of 50 ° C.
  • the bottoms of the falling-film evaporator are subjected to a bottom draw stream 3 containing 50% by weight of formaldehyde and 50% by weight of water.
  • the head-off stream 4 of the evaporator contains 20% by weight of formaldehyde, the remainder being water.
  • the bottom draw stream 3 is fed to the trioxane synthesis reactor 5. This is designed as a stirred tank and is operated at a temperature of 108 0 C.
  • the discharge stream 6 contains 9% by weight of trioxane and 66% by weight of formaldehyde, the remainder being water.
  • Stream 6 is fed to a first distillation column 7 on the fifth tray.
  • the first distillation column 7 is operated at a pressure of 1 bar.
  • the head temperature is about 99 ° C
  • the bottom temperature is about 104 0 C.
  • the first distillation column 7 contains 24 trays.
  • the first distillation column 7, a stream 9 is removed at the bottom with a concentration of 80 wt .-% formaldehyde and 20 wt .-% water.
  • the stream 8 is taken off with a concentration of 34% by weight of trioxane, 16% by weight of formaldehyde and 50% by weight of water.
  • the stream 8 is fed to a second distillation column 10. This is operated at a pressure of 4 bar.
  • the head temperature is approx. 142 ° C, the sump temperature is approx. 166 ° C.
  • the second distillation column has 40 trays, the feed stream 8 is fed to the bottom 20.
  • this column 10 is fed with a recycle stream 11 from the process to the 30th floor.
  • the recycle stream 11 contains 71% by weight of trioxane and 6% by weight of formaldehyde, the remainder being water.
  • a stream 14 with 64 wt .-% of trioxane, 8 wt .-% formaldehyde and 28 wt .-% water is removed.
  • the overhead stream 14 is fed to a third distillation column 12 on the 24th floor.
  • the third distillation column 12 contains 48 trays and is operated at a pressure of 1 bar.
  • the head temperature is about 101 ° C
  • the bottom temperature is about 104 0 C.
  • the stream 15 is removed.
  • the stream 15 contains 24 wt .-% formaldehyde, the rest is water.
  • the top stream of the third distillation column 12 is recycled as the recycle stream 11 to the second distillation column 10.
  • the stream 15 is fed to a fourth distillation column 16 on the 24th floor. Also, the fourth distillation column 16, the top stream 4 of the falling film evaporator is supplied to this bottom.
  • the fourth distillation column 16 is operated at a pressure of 4 bar.
  • the head temperature is about 137 ° C
  • the bottom temperature is about 145 ° C.
  • the top stream 18 contains 57 wt .-% formaldehyde, the rest is water.
  • the bottom stream 17 contains more than 98% by weight of water.
  • the top stream 18 is returned to the falling film evaporator 2.
  • a concentration unit 2 designed as a falling film evaporator is supplied with an aqueous formaldehyde solution 1 of 37% by weight of formaldehyde and 63% by weight of water.
  • the falling-film evaporator is operated at a pressure of 100 mbar and a temperature of 50 ° C.
  • the bottom of the falling film evaporator, a bottom draw stream 3 with 50 wt .-% formaldehyde and 50 wt .-% water is removed.
  • the head-off stream 4 of the evaporator contains 20% by weight of formaldehyde, the remainder being water.
  • the bottom draw stream 3 is fed to the trioxane synthesis reactor 5. This is designed as a stirred tank and is operated at a temperature of 108 0 C.
  • the discharge stream 6 contains 9% by weight of trioxane and 66% by weight of formaldehyde, the remainder being water.
  • Stream 6 is fed to a first distillation column 7 on the fifth tray.
  • the first distillation column 7 is operated at a pressure of 1 bar.
  • the top temperature is about 99 ° C
  • the bottom temperature is about 104 0 C.
  • the first distillation column 7 contains 24 trays.
  • the first distillation column 7 is at the bottom taken a stream 9 with a concentration of 80 wt .-% formaldehyde and 20 wt .-% water.
  • the stream 8 is taken off with a concentration of 38% by weight of trioxane, 15% by weight of formaldehyde and 47% by weight of water.
  • the stream 8 is fed to a second distillation column 10. This is operated at a pressure of 4 bar.
  • the head temperature is approx. 142 ° C, the sump temperature is approx. 166 ° C.
  • the second distillation column 10 has 40 trays, the feed stream 8 is supplied to the bottom 20.
  • the second distillation column 10 is fed with a recycle stream 11 from the process to the 30th tray.
  • the recycle stream 11 contains 71% by weight of trioxane and 6% by weight of formaldehyde, the remainder being water.
  • a stream 14 with 64 wt .-% of trioxane, 8 wt .-% formaldehyde and 28 wt .-% water is removed.
  • At the bottom of the product stream 13 is removed with more than 99 wt .-% trioxane.
  • the overhead stream 14 is fed to the third distillation column 12 on the 24th floor.
  • the third distillation column 12 contains 48 trays and is operated at a pressure of 1 bar.
  • the head temperature is about 101 ° C
  • the bottom temperature is about 104 0 C.
  • the stream 15 is removed.
  • the stream 15 contains 24 wt .-% formaldehyde, the rest is water.
  • the top stream of the third distillation column 12 contains 71% by weight of trioxane and 6% by weight of formaldehyde, the remainder being water. This stream is recycled as recycle stream 11 to the second distillation column 10.
  • the stream 15 is fed to a fourth distillation column 16 on the 24th floor. Also, the fourth distillation column 16, the top stream 4 of the falling film evaporator is supplied to this bottom.
  • the fourth distillation column 16 is operated at a pressure of 4 bar.
  • the head temperature is about 137 ° C
  • the bottom temperature is about 145 ° C.
  • the top stream 18 contains 57 wt .-% formaldehyde, the rest is water.
  • the bottom stream 17 contains more than 98% by weight of water.
  • the overhead stream 18 is recycled to the trioxane synthesis reactor 5.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Heterocyclic Compounds That Contain Two Or More Ring Oxygen Atoms (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

L'invention concerne un procédé intégré de production de trioxane à partir de formaldéhyde, lequel procédé consiste à introduire un flux A1 contenant de l'eau et du formaldéhyde ainsi qu'un flux de recirculation B2 essentiellement constitué d'eau et de formaldéhyde dans un réacteur de synthèse de trioxane, dans lequel le formaldéhyde est transformé en trioxane, pour obtenir un flux de produit A2 contenant du trioxane, de l'eau et du formaldéhyde, à introduire ce flux A2 dans une première colonne de distillation et à le distiller à une pression de 0,1 à 2,5 bars pour obtenir un flux B1 enrichi en trioxane et le flux B2 essentiellement constitué d'eau et de formaldéhyde, à introduire le flux B1 et un flux de recirculation D1 contenant du trioxane, de l'eau et du formaldéhyde dans une deuxième colonne de distillation et à les distiller à une pression de 0,2 à 17,5 bars pour obtenir un flux de produit C2 essentiellement constitué de trioxane et un flux C1 contenant du trioxane, de l'eau et du formaldéhyde puis à introduire le flux C1 dans une troisième colonne de distillation et à le distiller à une pression de 0,1 à 2,5 bars pour obtenir le flux de recirculation D1 contenant du trioxane, de l'eau et du formaldéhyde et un flux D2 essentiellement constitué d'eau et de formaldéhyde.
EP06792714A 2005-08-08 2006-08-04 Procede integre de production de trioxane a partir de formaldehyde Withdrawn EP1915359A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102005037293A DE102005037293A1 (de) 2005-08-08 2005-08-08 Integriertes Verfahren zur Herstellung von Trioxan aus Formaldehyd
PCT/EP2006/065089 WO2007017479A1 (fr) 2005-08-08 2006-08-04 Procede integre de production de trioxane a partir de formaldehyde

Publications (1)

Publication Number Publication Date
EP1915359A1 true EP1915359A1 (fr) 2008-04-30

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EP06792714A Withdrawn EP1915359A1 (fr) 2005-08-08 2006-08-04 Procede integre de production de trioxane a partir de formaldehyde

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US (1) US20100152466A1 (fr)
EP (1) EP1915359A1 (fr)
JP (1) JP2009504607A (fr)
KR (1) KR20080033363A (fr)
CN (1) CN101238115A (fr)
AU (1) AU2006277926A1 (fr)
BR (1) BRPI0614728A2 (fr)
CA (1) CA2617479A1 (fr)
DE (1) DE102005037293A1 (fr)
MX (1) MX2008001005A (fr)
NO (1) NO20080303L (fr)
WO (1) WO2007017479A1 (fr)

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CA2654892A1 (fr) 2006-06-12 2007-12-21 Basf Se Procede integre de preparation de trioxanne a partir de formaldehyde
DE102011051608A1 (de) * 2011-07-06 2013-01-10 Schott Solar Ag Verfahren und Vorrichtung zum gerichteten Erstarren einer Nichtmetall-Schmelze
EP3774762B1 (fr) * 2018-03-29 2023-08-30 Celanese Sales Germany GmbH Procédé de production d'un acétal cyclique dans un système réactionnel hétérogène

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US6209429B1 (en) * 1999-06-28 2001-04-03 Xerox Corporation Machining hollow cylinders
DE10361518A1 (de) * 2003-12-23 2005-07-28 Basf Ag Verfahren zur Abtrennung von Trioxan aus einem Trioxan/Formaldehyd/Wasser-Gemisch
DE10361516A1 (de) * 2003-12-23 2005-07-28 Basf Ag Verfahren zur Abtrennung von Trioxan aus einem Trioxan/Formaldehyd/Wasser-Gemisch mittels Druckwechsel-Rektifikation

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Title
See references of WO2007017479A1 *

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Publication number Publication date
AU2006277926A1 (en) 2007-02-15
KR20080033363A (ko) 2008-04-16
CA2617479A1 (fr) 2007-02-15
DE102005037293A1 (de) 2007-02-15
MX2008001005A (es) 2008-03-25
BRPI0614728A2 (pt) 2016-08-16
WO2007017479A1 (fr) 2007-02-15
NO20080303L (no) 2008-02-29
US20100152466A1 (en) 2010-06-17
JP2009504607A (ja) 2009-02-05
CN101238115A (zh) 2008-08-06

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