Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
  • C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
  • C07C37/74—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by distillation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
  • C07C37/685—Processes comprising at least two steps in series
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
  • C07C37/86—Purification; separation; Use of additives, e.g. for stabilisation by treatment giving rise to a chemical modification
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C39/00—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a six-membered aromatic ring
  • C07C39/12—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a six-membered aromatic ring polycyclic with no unsaturation outside the aromatic rings
  • C07C39/15—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a six-membered aromatic ring polycyclic with no unsaturation outside the aromatic rings with all hydroxy groups on non-condensed rings, e.g. phenylphenol
  • C07C39/16—Bis-(hydroxyphenyl) alkanes; Tris-(hydroxyphenyl)alkanes

Definitions

• Bisphenols as condensation products of phenols and carbonyl compounds are starting materials or intermediates for the preparation of a large number of commercial products. Of particular industrial importance is the condensation product of the reaction between phenol and acetone, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A, BPA).
• BPA serves as a starting material for the production of various polymeric materials such as, for example, polyarylates, polyetherimides, polysulfones and modified phenol-formaldehyde resins. Preferred fields of application are in the production of epoxy resins and polycarbonates.
• the selectivity of the reaction as well as the long-term stability of the catalyst is significantly influenced by the quality of the raw materials phenol and acetone used.
• BPA as a raw material for high-grade plastics such as polycarbonate therefore very high purity requirements of the Grund ⁇ used substances Phenol and acetone provided.
• purities of> 99.95% by weight for phenol and> 99.90% by weight for acetone with simultaneously low impurity levels (S ⁇ 0.5 ppm, Fe ⁇ 1 ppm) are typically positive for achieving high product purities and to minimize catalyst deactivation.
• EP-A-876 319 describes that commercial phenol is freed from interfering impurities by treatment with molecular sieve and thus ensures better usability in a process for producing BPA becomes.
• EP-A-680 913 describes the use of modified acidic ion exchangers for the removal of hydroxyacetone from phenol for BPA synthesis.
• a product mixture is formed which, in addition to unreacted phenol and optionally acetone, primarily contains BPA and water.
• typical by-products of the condensation reaction occur, for example 2- (4-hydroxyphenyl) -2- (2-hydroxyphenyl) propane (o, p-BPA), substituted indanes, hydroxyphenylindanols, hydroxyphenylchromans, substituted xanthenes and higher condensed compounds having three or more phenyl rings in the molecular skeleton.
• the adduct crystals obtained in this way typically have a purity of> 99% by weight BPA based on BPA and the secondary components with a phenol content of about 40% by weight, based on the total adduct crystal amount.
• suitable solutions which typically contain one or more components from the group of acetone, water, phenol, BPA and Maukom ⁇ components, the adduct crystals can be freed from superficially adhering impurities.
• the Zusam ⁇ composition of the mother liquor at this point and thus the composition of the outfeed subset typically consists of 70 to 90 wt .-% phenol, 3 to 15 wt .-% BPA and 3 to 15 wt .-% minor components and isomers, the were formed in the reaction. Since ultimately only the last-mentioned proportion of secondary components has to be removed from the process, the discharged quantity is subjected to further work-up steps in order to minimize material losses.
• a portion of the BPA contained in the recirculated amount is recovered by distilling off part of the phenol from the withdrawn partial stream - A -
• a filtrate consisting of typically 60 to 90% by weight of phenol, 3 to 12% by weight of BPA and 3 to 18% by weight of secondary components is obtained. From this filtrate, the phenol contained is typically distilled off to ⁇ 10 wt .-% residual content and the resulting residual resin containing ⁇ 10 wt .-% phenol, 14 to 80 wt .-% BPA, 20 to 86 wt .-% secondary components of disposal fed.
• the invention relates to a process for the continuous separation of phenol from a partial stream produced in the production of bisphenol A containing 40 to 90 wt .-% of phenol, 5 to 40% by weight of bisphenol A and 5 to 40% by weight of secondary components which are formed in the reaction of phenol and acetone to give bisphenol A,
• the phenol distilled off in step b) preferably has a purity of> 99.8% by weight.
• the technical problem is solved by acid-catalyzed cleavage of the exit stream in a residence time vessel and continuous separation of the phenol via a vacuum column with high separation capacity.
• FIG. 1 shows a preferred embodiment of the method according to the invention.
• Another partial stream 8 of the bottom product is fed to a residence time tank 11.
• the acid-catalyzed isomerization takes place. sierang and cleavage of BPA and minor components to form phenol.
• the cleavage is accelerated by the addition of suitable acids (stream 12) through a metering unit 13.
• the phenol-containing effluent 14 of the residence time vessel 11 is combined with the recirculated substream 1 and thus returned to the distillation unit 2 for the recovery of phenol.
• the process is operated continuously and reaches an equilibrium state after a short time.
• the partial stream 1 fed out from the process for producing bisphenol A can be any product stream from a process for producing BPA which contains the following components: 40 to 90% by weight of phenol, 5 to 40% by weight of bisphenol A and 5 to 40% by weight of secondary components which are obtained in the reaction of phenol and acetone to give bisphenol A:
• Partial stream 1 is preferably a recycled partial stream from a BPA production process with suspension crystallization and solid-liquid separation, wherein a partial stream of the filtrate is removed from the solid-liquid separation for the purpose of discharging by-products in the direction of the process according to the invention for the separation of phenol.
• this partial stream 1 is passed through an additional rearrangement unit before being fed into the distillation column 2, whereby a portion of the BPA contained in the filtrate is recovered by treatment with acidic ion exchanger, followed by partial distilling off of phenol, crystallization and solid-liquid separation and fed to the main process becomes.
• the filtrate of the solid-liquid separation of the rearrangement unit serves as the feed stream 1 of the distillation column. 2
• the distillation column 2 must have at least 5 theoretical plates, preferably at least 10 theoretical plates, to separate other mecanicsie ⁇ dender components such as For example, to allow isopropenylphenol and to ensure a purification of the resulting phenol to a purity of> 99.8 wt .-% at the top of the column.
• the distillation is preferably operated at an absolute pressure at the top of the column of 70 to 200 mbar, preferably 90 to 120 mbar.
• the residence time tank 11 must be designed in such a way that an average hydrodynamic residence time of the circulation stream 8 of at least 2 hours, preferably at least 4 hours, is set in order to achieve an effective and as complete as possible cleavage of BPA and by-products.
• the residence time reactor can in this case be operated completely filled in upflow or downflow or in a position-controlled manner.
• the isomerization and the associated cleavage in the residence time vessel 11 in step d) is carried out in the presence of an acidic catalyst.
• acidic catalyst (stream 12) for the cleavage in step d) can in principle a variety of strongly acidic heavy or non-volatile Brönsted acids are used, including phosphoric acid or its higher condensates, sulfuric acid, alkanesulfonic acids with> 4 carbon atoms in the alkane chain, aromatic Sulfonic acids, arylalkane sulfonic acids or phosphonium acids.
• heterogeneous cleavage catalysts such as, for example, strongly acidic aluminum oxide, supported Lewis acids, acidic zeolites or other clays or polystyrrolesulfonic acids.
• the metering unit 13 is omitted and the heterogeneous catalyst is introduced by a suitable retaining structure in the residence time tank 11 and replaced if necessary.
• metering can be effected as stream 12 via the metering unit 13 into the circulation stream of the bottoms product of the distillation column 2.
• the metering can also take place in the input stream 8 into the residence time container 11 or into the output stream 14 out of the residence time container 11.
• the metering can also be carried out in the partial stream 1 in the distillation column 2.
• the metering is in the circulation stream of the bottom product of the distillation column 2 of the column.
• X is the mass fraction of phenol in substream 1
• c for effective cleavage is between 0.001% and 2%, preferably between 0.005 and 1%, more preferably between 0.01 and 0.2%.
• the temperature in the residence time vessel 11 must be> 190 ° C., preferably> 200 ° C., for effective isomerization and cleavage.
• the heat input in a preferred embodiment takes place directly through the evaporator 7 of the distillation column 2. This means that the input stream 8 into the residence time vessel 11 is not heated by a separate heat exchanger and the bottom of the column 2 and the dwell tank 11 are operated at the same temperature.
• composition (without phenol content) in all examples and comparative examples is: p, p-BPA 35-40% by weight, o, p-BPA 9 to 12% by weight, hydroxyphenyl-substituted indanes 15 to 19% by weight. %, hydroxyphenyl-substituted chromans 18 to 22% by weight, trisphenol 3 to 5% by weight, other constituents 9 to 12% by weight. This corresponds to a typical composition of a feed stream from a bisphenol A production plant.
• Table 1 shows the purity C (5) and the mass flow M (5) of the phenol stream 5 obtained at the top of the column for the various conditions on which Examples 1 to 7 are based.
• the column 2 used has 20 theoretical plates and was operated with a reflux ratio of about 0.6 and with the pressures that set in setting the temperature T (I l) at the bottom of the column 2 in the thermodynamic equilibrium.
• the temperature in the residence time container 11 is equal to the temperature at the bottom of the column 2.
• the values indicated relate to equilibrium conditions which occur after a few hours when the column is operated continuously.
• the cleavage in the residence time vessel 11 is assisted by the addition of sulfuric acid.
• Comparative Example 7 is carried out with the already in Examples 1 to 5 Column 2, but the residence time 11 is bypassed, so that no residence time for cleavage is available. As a result, despite the addition of sulfuric acid, no high yield of phenol Y in the phenol stream 5 is realized.
• T (11) temperature in the residence time container 11
• M (8) mass flow of bottom product through the residence time vessel 11
• ⁇ (l 1) hydrodynamic residence time in the residence time vessel (11).

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

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• 2004
  • 2004-07-02 DE DE102004032232A patent/DE102004032232A1/de not_active Withdrawn
• 2005
  • 2005-06-18 KR KR1020067027776A patent/KR20070028473A/ko not_active Ceased
  • 2005-06-18 ES ES05756999.8T patent/ES2550008T3/es not_active Expired - Lifetime
  • 2005-06-18 CN CN2005800225273A patent/CN1980876B/zh not_active Expired - Fee Related
  • 2005-06-18 WO PCT/EP2005/006603 patent/WO2006002788A1/de not_active Ceased
  • 2005-06-18 EP EP05756999.8A patent/EP1765752B1/de not_active Expired - Lifetime
  • 2005-06-18 RU RU2007103892/04A patent/RU2401255C2/ru not_active IP Right Cessation
  • 2005-06-18 JP JP2007518497A patent/JP2008504320A/ja not_active Withdrawn
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