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
• • 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

Definitions

• the present invention relates to a process for the preparation of bis (4-hydroxy-aryl) alkanes and aromatic hydroxy compounds which are catalyzed by acid
• Adduct of the bis (4-hydroxyaryl) alkane and the aromatic hydroxy compound used as the starting material which is then freed from the aromatic hydroxy compound by distillation.
• the most important example on an industrial scale is the production of bisphenol A, in which an adduct of bisphenol A (BPA) and phenol is obtained as an intermediate. Even after purification, for example by recrystallization, this adduct still contains traces of acid (approx. 5 to 1010 "6 mol acid / mol BPA) due to the acid-catalyzed preparation. These traces of acid lead to the separation of the phenol from bisphenol A, which is associated with thermal stress, partial decomposition of the bisphenol and the formation of by-products.
• the adducts of bis (4-hydroxy-aryl) alkanes and aromatic hydroxy compounds which can be used in the process according to the invention can be obtained by reacting aromatic hydroxy compounds which are not substituted in the p-position and have no second-order substituents, such as cyano, carboxy or nitro groups contain, for example phenol, o- and m-cresol, 2,6-dimethylphenol, o-tert-butylphenol, 2-methyl-6-tert-butylphenol, o-cyclohexylphenol, o-phenylphenol, o-isopropylphenol, 2- Methyl-6-cyclopentyl-phenol, o- and m-chlorophenol, 2,3,6-trimethylphenol, preferably phenol, o- and m-cresol.
• 2,6-dimethylphenol, o-tert-butylphenol and o-phenylphenol particularly preferably phenol
• ketones with at least one aliphatic group on the carbonyl function for example acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, diethyl ketone, acetophenone, cyclohexanone, cyclopentanone.
• Methyl, dimethyl and trimethyl cyclohexanones which may also have geminal methyl groups, e.g. 3,3-dimethyl-5-methylcyclohexanone (hydroisophorone), preferably acetone, acetophenone,
• Cyclohexanone and its homologues bearing methyl groups: acetone is particularly preferred.
• the adduct of bisphenol A and phenol is preferably used as the starting material.
• the invention thus relates to a process for the preparation of bis (4-hydroxyaryl) alkanes from adducts of bis (4-hydroxyaryl) alkanes and aromatic hydroxy compounds, in which
• step c) the inert gas stream is cleaned, compressed and returned in step a).
• the monophenol is separated from the bis (4-hydroxyaryl) alkane from the melt of the adduct of bis (4-hydroxyaryl) alkane and aromatic hydroxy compound at temperatures between 150 ° C. to 230 ° C., preferably at 170 ° C. to 210 ° C. by expelling the monophenol by introducing an inert gas (eg nitrogen).
• an inert gas eg nitrogen
• the ratio of gas to adduct amount is preferably approx.
• the stripping can optionally be facilitated by reducing the pressure in the unit used to separate the monophenol, but is preferably carried out under normal pressure.
• the stripping of the monophenol with the inert gas is carried out in known apparatuses, for example in a packed, flooded column.
• the monophenol is removed from the inert gas cycle system, for example by condensation on a heat exchanger.
• the circulating inert gas can be cleaned by passing it over a fixed bed adsorbent (activated carbon, zeolite etc.) or in a preferred one
• a weakly alkaline aqueous solution is used as the washing medium.
• the value of the aqueous solution used should be in the range from 7 to 12, preferably 7.5 to 11, very particularly preferably 8 to 10. All basic substances can be used to prepare such an aqueous solution; alkali and alkaline earth metal hydroxides are preferred. In a preferred embodiment, the pH is checked before and after washing, so that excess and
• the inert gas stream can then be fed to a second wash.
• the washing medium is then preferably pH neutral.
• the bis (4-hydroxyaryl) alkanes produced by the process according to the invention are distinguished by a very good inherent color and high purity. in particular, they have low levels of aromatic hydroxy compounds ( ⁇ 100 ppm, preferably ⁇ 50 ppm) and decomposition products (e.g. isopropenylphenol, dimeric isopropenylphenol).
• Polymers such as polycarbonates or epoxides with a low intrinsic color can be produced from the bis (4-hydroxyaryl) alkanes produced by the process according to the invention.
• a 1 t / h melt mixture BPA / phenol (60/40 wt .-%) is introduced into a desorber. 225 m 3 of nitrogen / h (recycle stream) are continuously introduced into the desorber. The phenol is taken up by the nitrogen and then condensed by means of a heat exchanger. The nitrogen is then fed to a compressor, the sealing liquid of which is strongly diluted NaOH solution (pH 10), compressed, and in a gas scrubber, which is filled with VE
• Example 2 As in Example 1, except that a dilute NaOH solution (pH 13) is used to wash the nitrogen. A BPA melt with a melt color number of 12 Hazen is then obtained. The phenol level in BPA is 60 ppm, which is still on

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

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Citations (1)

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• 1998
  • 1998-10-17 DE DE19848026A patent/DE19848026A1/de not_active Ceased
• 1999
  • 1999-10-01 TW TW088116896A patent/TW517046B/zh not_active IP Right Cessation
  • 1999-10-05 AU AU60893/99A patent/AU6089399A/en not_active Abandoned
  • 1999-10-05 KR KR1020017004787A patent/KR100608922B1/ko not_active Expired - Fee Related
  • 1999-10-05 ES ES99947458T patent/ES2190253T3/es not_active Expired - Lifetime
  • 1999-10-05 CN CNB998122572A patent/CN1173911C/zh not_active Expired - Fee Related
  • 1999-10-05 MD MDA20010161A patent/MD2705B2/ro unknown
  • 1999-10-05 HK HK02103685.2A patent/HK1042080A1/zh unknown
  • 1999-10-05 EP EP99947458A patent/EP1121339B1/de not_active Expired - Lifetime
  • 1999-10-05 BR BR9914607-0A patent/BR9914607A/pt not_active IP Right Cessation
  • 1999-10-05 WO PCT/EP1999/007358 patent/WO2000023410A1/de not_active Ceased
  • 1999-10-05 US US09/807,645 patent/US6384288B1/en not_active Expired - Lifetime
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  • 1999-10-05 JP JP2000577138A patent/JP2002527497A/ja active Pending
  • 1999-10-05 DE DE59904188T patent/DE59904188D1/de not_active Expired - Lifetime
• 2002
  • 2002-01-03 US US10/037,995 patent/US20020055661A1/en not_active Abandoned

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