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
  • C07C37/11—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms
  • C07C37/20—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms using aldehydes or ketones
• • 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
  • C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
  • C07C37/84—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by crystallisation
• • 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
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• This invention relates to a method of producing bisphenol A used for manufacturing plastics, more particularly polycarbonate resins and their blends used for manufacturing structural components, in the automotive industry, for manufacturing medical devices and sports equipment as well as everyday objects.
• bisphenol A 2,2-bis-(4-hydroxyphenyl)propane
• p,p '-BPA polysulphonic resins
• polyetherimides as well as additives to plastic materials - e.g. flame retardants such as tetrabromobisphenol A, bisphenol A phenyl phosphates and thermal stabilizers for poly(vinyl chloride).
• Bisphenol A can be obtained by condensing acetone and phenol in the presence of highly acidic catalyst, e.g. Bronsted or Lewis acids.
• highly acidic catalyst e.g. Bronsted or Lewis acids.
• bisphenol A is mostly obtained by condensation reaction of acetone with phenol in the presence of an acidic ion- exchange catalyst such as sulphonated styrene-divinylbenzene copolymer, and optionally a promoter increasing the yield and selectivity of the reaction (thiol compounds, e.g. 2,2- dimethyl-l,3-thiazolidine and 2-aminoethanethiol).
• a synthesis unit for bisphenol A is comprised of a multi-stage system of fixed-bed flow reactors connected in series via heat exchangers which allow maintaining the target temperature range in each reactor.
• the method of dosing acetone and post-crystallization liquors obtained at the stage of BPA isolation and purification varies according to the embodiment.
• Numerous embodiments consist in recycling post-crystallization liquors in the form of non-reacted phenol and non-crystallized BPA to the concentration stage prior to crystallization which decreases significantly the consumption of raw materials.
• An additional advantage resulting from recycling the mother liquor to the synthesis stage consists in limitation of formation of 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane (so-called o,p '-BP A isomer) as the system approximates then more closely the state of equilibrium of p,p '-BPA and o,p '-BPA isomers.
• a method for reducing the degradation of BPA consists in neutralizing acidic impurities present in the post-reaction mixture by introducing neutralizing compounds (carbonates and alkali metal hydroxides), filtering raw BPA through cation-exchange resin (Na, K, Li, Ca, Mg) or inorganic ion-exchanger (patent no. US 6512148).
• Methods for reducing the scale of formation of by-products include e.g. an isomerization reaction of o,p '-BP A to ⁇ , ⁇ '-BPA (JP 08333290) which takes advantage of the fact that after crystallization of the BP A/phenol adduct, the concentration of the o,p '-BP A isomer is higher than the equilibrium concentration and the process of catalytic decomposition occurs under the influence of acidic (WO 0040531) or basic (PL 181992) catalysts.
• Bisphenol A is an unstable compound and undergoes gradual degradation under the influence of temperature, light, in the presence of acids, bases and oxygen.
• the decomposition of a bisphenol A molecule occurs due to the instability of the bond between the quaternary carbon atom and the phenolic hydroxyl group.
• products of the degradation even in small quantities present in BPA, inhibit the increase in molecular weight and reduce mechanical and optical properties of the polymer.
• the degradation results in the formation of numerous BPA impurities during BPA heat treatment and purification.
• Stabilizers are chemical compounds introduced into the material in small quantities (1-2%).
• the variety of types and structures of chemical compounds used as stabilizers allows selecting a stabilizer suitable for the material to be stabilized and the anticipated conditions for its storage, use or processing.
• the addition of phosphoric acid (1) to raw BPA prior to distillation-based purification inhibits the formation of colour complexes of metals with phenol derivatives and BPA during heat treatment (EP 0816319).
• a distinct stabilizing effect can be achieved by the method of BPA crystallization from phenol at a temperature of 185-220°C in non-oxygen atmosphere (JP 6025045) or by introducing additives such as boric acid, alkyl titanates, phthalic anhydride, alkali metal phosphates (V) and (III) (CS 272518).
• the object of the invention was to develop a method for producing bisphenol A, in which the catalytic system is characterised by longer lifetime and the synthesis product - by greater thermal stability.
• reaction mixture containing acetone, phenol and products of the reaction between phenol and acetone is contacted with an ion-exchange catalyst in at least two reactors until the total water content is not greater than 2.5 cg/g, wherein acetone and phenol are fed into reactor 1 and the post-reaction mixture from reactor 1, mixed in mixer 2 with post-crystallization liquors from crystallizers 8 and acetone, is fed into reactor 3;
• the post-reaction mixture after reactor 3 is mixed in mixer 4 with part of the phenol solution not greater than 40 cg/g, obtained as a result of the contact between the dewatering mixture containing a maximum of 1.0% of water, with an ion-exchange catalyst in at least one reactor 5;
• the post-reaction mixture from mixer 4 is contacted in adsorber 6 at a maximum temperature of 150°C and flow rate not greater than 10 m/h with a phenol solution pH stabilizer in the form of a fixed-bed with grain size not greater than 1.2 mm, containing carboxyl and/or hydroxyl and/or amide groups, until the post-reaction mixture reaches a pH of 5-6 after adsorber 6,
• the post-reaction mixture in adsorber 6 is concentrated in distillation column 7 by partial or total evaporation of volatile substances as a distillate containing phenol, acetone and water at the boiling point under normal pressure not greater than 200°C, and bisphenol A is crystallized from the distillation residue;
• At least 60% of the phenol solution in reactor 5 is contacted in adsorber 9, at a maximum temperature of 150°C and flow rate not greater than 10 m/h, with a phenol solution pH stabilizer in the form of a fixed bed with grain size not greater than 1.2 mm, containing carboxyl and/or hydroxyl and/or amide groups, until the mixture after adsorber 9 reaches a pH of 5-6 and the resulting solution is mixed with the distillate from distillation column 7 containing phenol, acetone and water, and fed into distillation column 10,
• phenol separated in column 10 is recycled to reactor 1, acetone to reactor 1 and/or 3 and the water fraction is removed from the installation as waste water.
• the dewatering mixture containing at maximum 1 cg/g of water is contacted with an ion-exchange catalyst in reactor 5 at a maximum temperature of 95°C and flow rate not greater than 2.0 m/h.
• reaction mixture in reactors 1 and 3 is contacted with an ion- exchange catalyst at a maximum temperature of 85°C and flow rate not greater than 6 m/h.
• reaction mixture or the dewatering mixture can be fed into each reactor, as the need may be.
• a phenol solution pH stabilizer is used, with a molar ratio of hydroxyl (-OH) groups to carboxyl (-COOH) groups not greater than 1 : 1.
• a phenol solution pH stabilizer is used, with a molar ratio of amide (- CO H 2 ) groups to hydroxyl (-OH) groups not greater than 1 :2.
• the synthesis of bisphenol is carried out in a reaction system comprised of 3 ion- exchange reactors of 0.5 dm 3 each. The same catalyst is placed in the reactors.
• Table 1 shows the characteristics of an ion-exchange catalyst used in the condensation reaction of phenol with acetone.
• Reactors 1 and 3 are fed with the reaction mixture, while reactor 5 - with the dewatering mixture.
• Reactor 1 is fed on a continuous basis with the reaction mixture composed of acetone, water and phenol at a flow rate of 1.0 kg/h.
• the reaction mixture from reactor 1 is mixed with post-crystallization liquors from crystallizers 8, obtained during the separation of the synthesis product, the p,p '-BPA isomer, by the combined method of suspension crystallization and fractional crystallization.
• the solutions are mixed in a mixer of 5.0 dm 3 provided with a horseshoe agitator of 120 rpm and plate heater with temperature adjustable in the range of 25-100°C.
• the post-crystallization liquors are mixed in mixer 2 with the reaction solution from reactor 1 at a temperature of 72.5°C, and then the resulting solution, obtained by mixing the streams, is cooled down to 55°C and added with 80.8 g of acetone. After thorough mixing, the mixture is fed into reactor 3.
• Table 4 shows the composition and quantity of each solution.
• Table 5 shows the conditions for bisphenol synthesis in reactor 3.
• reactor 5 a process of dewatering the ion-exchange catalyst is carried out in reactor 5.
• Reactor 5 is fed with the dewatering mixture composed of 0.3 % of water and 99.70% of phenol.
• Table 6 shows the conditions for dewatering of the ion-exchange catalyst in reactor 5.
• the phenol solution from reactor 5 is divided into two streams at a ratio of 32% to 68%.
• the smaller stream of 174.7 g/h (0.174 kg/h) is mixed with the post-reaction solution from reactor 3 (2.127 kg/h).
• the solutions are mixed in mixer 4 of 3.0 dm 3 at a temperature of 72°C and a mixture of 2.301 kg/h is obtained which is then fed into adsorber 6 filled with a phenol solution pH stabilizer.
• the adsorber 6 is provided with 0.5 dm 3 of polymer packing with grain size of 0.2 to 1.1 mm, containing carboxyl (-COOH) and hydroxy 1 (-OH) functional groups.
• Table 7 shows the characteristics of the packing material in the adsorber.
• the post-reaction mixture from reactor 3 and part of the phenol solution is directed to mixer 4, and then the entire stream is filtered through the stabilizer bed in adsorber 6 at a flow rate of 4.2 m/h and temperature of 72°C.
• the mixture after adsorber 6 with a pH of 5.5 is concentrated by vacuum distillation under pressure of 21 kPa in column 7 packed with glass rings, at a distillate-to-reflux ratio of 3.0: 1.
• the temperature of the liquid in the column pot is maintained at 135°C.
• Table 8 shows the composition of the streams resulting from concentrating the solution of the synthesis products.
• the other part of the phenol solution from reactor 5 (68%, 0.372 kg/h) is stabilized by contacting it with a pH stabilizer in adsorber 9 provided with packing of 0.2 dm 3 .
• the stabilization of the phenol solution is carried out at a temperature of 72°C with packing identical to that used for pH stabilization of the stream of the synthesis products in adsorber 6 (characteristics of the adsorber packing in Table 7).
• Adsorber 9 is fed on a continuous basis at a flow rate of 1.2 m/h.
• the phenol solution after adsorber 9 with a pH of 5.5 and flow rate of 0.372 kg/h is then mixed with the distillate (0.496 kg/h) from distillation column 7 (composition of the distillate in Table 8).
• the separation of the acetone-water-phenol mixture is carried out in a system of two columns 10 with structural packing, and the mixture is separated into phenol and water-acetone fraction in the first column, and then acetone is isolated from the acetone-water fraction in the other column.
• the composition of each stream from the distillation separation of the acetone-water-phenol solution is shown in Table 9.
• the p,p '-BP A isomer, the main synthesis product, is obtained in crystallizers 8 by two-stage crystallization which consists in a combination of suspension crystallization and fractional crystallization.
• the suspension crystallization of the bisphenol A/phenol adduct is carried out with the use of 1.804 kg/h of the concentrated mixture of the products specified in Table 8.
• the crystallization process is carried out in crystallizers 8.
• the following streams are mixed at a temperature of 80°C in an agitated crystallizer with a heating and cooling jacket, which makes it possible to precisely regulate the temperature of the liquid in the range of 20 to 100°C:
• the contents of the crystallizer are cooled down at a rate of 7°C per hour in the range of 80°C to 52°C.
• the crystallization of the bisphenol A/phenol adduct from the phenol solution is terminated as soon as the temperature of 52°C is reached.
• the bisphenol A/phenol adduct crystals are separated from the post-crystallization liquors by filtration.
• the phases are separated with the use of a pressure filter provided with a partition with mesh size of 10 ⁇ .
• the filtration is carried out in inert nitrogen atmosphere at a temperature of 52°C.
• Part of the post-crystallization liquors is recycled to the reaction system, to mixer 2, while the other part of the liquors, 0.886 kg/h, undergoes concentration and isomerization of o,p'-EPA isomer to p,p '-BP A, and the total solution enriched with the p,p '-BP A isomer is recycled to the suspension crystallization stage.
• the adduct crystals of 0.483 kg/h is transferred to a rotary evaporator and then melted at a temperature of 110°C and the composition is averaged.
• the raw ⁇ , ⁇ '-BPA isomer is obtained as a result of thermal decomposition of the adduct at a temperature over 120oC and gradual distillation of phenol.
• the distillation of phenol is carried out under reduced pressure of 25 mm Hg. During the distillation of phenol the temperature is gradually increased from 110°C to 165°C at a rate of 50°C/hour.
• the decomposition of the adduct is terminated when the phenol content in bisphenol A is reduced to 0.07%.
• the decomposition of the adduct results in 0.315 kg/h of the raw bisphenol A which is then purified by fractional crystallization in a tubular crystallizer.
• the purification by fractional crystallization results in the end product - 0.294 kg/h of bisphenol A with parameters as specified in Table 10.

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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2012
  • 2012-04-16 PL PL398819A patent/PL217484B1/pl unknown
• 2013
  • 2013-02-07 CN CN201380031512.8A patent/CN104540799B/zh not_active Expired - Fee Related
  • 2013-02-07 WO PCT/PL2013/050005 patent/WO2013157972A2/en active Application Filing
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