Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C315/00—Preparation of sulfones; Preparation of sulfoxides
• • 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
  • Y02P20/582—Recycling of unreacted starting or intermediate materials

Definitions

• the present invention relates to an improved semi-continuous process for the preparation of 4, 4'-dihydroxydiphenyl sulfone with the steps
• 4, 4 '-Dihydroxydiphenylsulfon (“4, 4' -Bisphenol S”) is used, among other things, as an electroplating aid, as a raw material for the production of condensation resins, for example for use as leather tanning agents, and for the production of fibers and especially plastics such as Polyether sulfones of great economic interest. Since the properties of the polymers produced from 4, 4'-dihydroxydiphenyl sulfone strongly depend on the degree of purity and on the isomer ratio of the monomers used, selective synthesis methods for 4,4'-dihydroxydiphenyl sulfone are sought. Furthermore, for economic and ecological reasons, synthetic processes with little or no waste streams are desired.
• Synthesis processes which use combustible inert organic solvents such as methanol, ethanol, o-dichlorobenzene or toluene in the isolation of 4,4'-dihydroxydiphenylsulfone from the reaction mixture, for example in JP-A 50/106 937, CN-A 87/100 796 , EP-A 220 004 or WO 92/02493, are also of concern for ecological and safety reasons.
• combustible inert organic solvents such as methanol, ethanol, o-dichlorobenzene or toluene
• US Pat. No. 3,297,766 discloses a semi-continuous process for the preparation of 4,4′-dihydroxydiphenyl sulfone, in which sulfuric acid is reacted with phenol at 180-188 ° C. while the water of reaction is continuously distilled off, and the reaction mixture is then reduced to 55-75 ° C cooled and the precipitated solid is filtered off and washed with water. This gives a mixture from 4,4'- and 2,4 '-dihydroxydiphenylsulfone.
• the waste streams from the filtration and washing, as well as the phenol discharged when the water of reaction is distilled off, are returned in the next cycle of the manufacturing process.
• JP-A 50/106 936 describes the preparation of 4, 4 '-Dihydroxydi - phenyl sulfone by reacting phenol with a sulfonating agent such as sulfuric acid at 180-200 ° C and crystallization and btrennung A of 4, 4' -Dihydroxydiphenylsulfons described.
• a sulfonating agent such as sulfuric acid at 180-200 ° C and crystallization and btrennung A of 4, 4' -Dihydroxydiphenylsulfons described.
• the crude reaction product is dissolved or dispersed in an aqueous 3 to 8% by weight phenol solution and the 4, 4' -dihydroxydiphenylsulfone is crystallized and separated with or without cooling.
• JP-A 50/106 936 provides the desired product in high isomer purity, it has the disadvantage that it works with large amounts of aqueous treatment solution for the isolation from the reaction mixture. On the one hand, these quantities require large-sized and therefore expensive equipment, and on the other hand, the yield is reduced. Furthermore, the presence of large amounts of phenol in isolating the product has the disadvantage that the phenol can easily adhere to the product as an impurity, forming adduct complexes.
• T ASK of the present invention it was a IMPLEMENTATION at the steps of the U and to provide the isolation of the product from the reaction mixture of inert organic solvents free preparation process 4, 4 'dihydroxydiphenyl sulphone, wherein the waste streams are recycled to the manufacturing process NEN kön- , which delivers the desired product in high isomer purity and high yield even without subsequent purification operations and which manages to isolate the product from the reaction mixture with the smallest possible amount of treatment solution, which should be largely free of unreacted phenol.
• the semicontinuous process defined at the outset for the production of 4, 4'-dihydroxydiphenyl sulfone was found, which is characterized in that, in carrying out step (b), crude product and water in a weight ratio of 85:15 to 55:45, preferably 75:25 to 60:40.
• the hot water used to suspend the reaction mixture is free of inert organic solvents, in particular water-miscible such as methanol, ethanol, isopropanol or acetone or optionally halogenated hydrocarbons such as toluene, chlorobenzene or dichlorobenzenes.
• inert organic solvents in particular water-miscible such as methanol, ethanol, isopropanol or acetone or optionally halogenated hydrocarbons such as toluene, chlorobenzene or dichlorobenzenes.
• the water added to treat the reaction mixture in step (b) has a temperature of 80 ° C. to 100 ° C. Particularly good results are achieved with water from 90 ° C to 100 ° C. In principle, you can also work at temperatures above 100 ° C, for example at 100 ° C to 130 ° C, if you carry out the treatment with water in a closed apparatus under pressure.
• the treatment water can also be added in the form of steam. The duration of the treatment with water is not critical, as a rule this is 5 minutes to 5 hours. Usually takes place during loading mechanical mixing with water, for example by stirring.
• the crude product is suspended in water in step (b) and the product is filtered off at approximately the same temperature.
• Approximately the same temperature usually means working in a temperature interval of approx. 10 ° C, in particular approx. 5 ° C. In this embodiment, cooling of the suspension, which would result in the crystallization of dissolved fractions, is avoided.
• the suspension (“slurrying”) and the filtering off can be carried out using conventional techniques and apparatus such as, for example, stirred kettles, mixers or kneaders for the suspension and filter-suction or centrifuges for the filtering off.
• the product filtered off in step (b) is washed with hot water at least 40 ° C., preferably 80 ° C. to 100 ° C., in particular 90 ° C. to 100 ° C.
• the amount of water used for post-washing should be as small as possible and is generally a maximum of 100%, preferably a maximum of 85% of the water used to suspend the reaction mixture.
• step (b) in which the suspension of the crude product in water and the filtering off of the product at approximately the same temperature in a temperature range from 80 ° C. to 100 ° C., in particular 90 ° C. to 100 ° C, carried out and washed with a maximum of 100, in particular a maximum of 85% of the water used for suspending the reaction mixture, which also has approximately the same temperature as for suspending and filtering off.
• step (b) the product produced in step (b) according to the abovementioned measures generally already has an average purity of> 96%, in particular> 97.5%, and an average isomer purity of> 98% , in particular of> 98.4%.
• This high purity and isomeric purity are achieved in that, in contrast to all previously known processes, the already very pure crude crystals of 4, 4'-dihydroxydiphenyl sulfone formed during the reaction in step (a) are not destroyed, but rather by the hot treatment water are freed from the 2, 4'-dihydroxydiphenyl sulfone which is more soluble in the mother liquor and enriched therein.
• a further advantage of the process according to the invention is that the mother liquor from step (b), which mainly contains the 2,4′-dihydroxydiphenyl sulfone, after distilling off the water at the beginning of the next cycle of the manufacturing process in step (a) is used again with skillful use of the chemical equilibrium becomes. This transforms the mother liquor residue into phenolsulfonic acid. The distilled water can also be used in the next cycle again in step (b).
• the process according to the invention is also notable for a high overall yield of mostly over 90%, in particular 92% or more, in each case based on the phenol used.
• the 4,4'-dihydroxydiphenyl sulfone produced by the process according to the invention is also notable for its good crystallization behavior, i.e. the crystals obtained are large and well developed and low in dust, so that they are easy to handle and meter.
• Concentrated sulfuric acid, oleum (“fuming” sulfuric acid) or sulfur trioxide (“sulfuric anhydride”) is preferably used as the sulfonating agent in step (a).
• Concentrated sulfuric acid with a content of approx. 70 to 100% by weight is particularly preferred, for example the commercially available approx. 96% by weight sulfuric acid.
• Step (a) of the method according to the invention can be carried out as described below.
• Phenol and the sulfonating agent can be introduced together and then brought to the reaction temperature.
• the phenol can also be metered in in portions or continuously in the course of the reaction, in particular after the heating phase.
• the reaction temperature is usually 140 ° C to 230 ° C, in particular 150 ° C to 200 ° C, especially 160 ° C to 175 ° C. At a reaction temperature of less than 165 ° C., it is expedient to work under reduced pressure in order to ensure the boiling of the phenol.
• the molar ratio of phenol to the sulfonating agent, for example sulfuric acid is normally 1.6: 1 to 25: 1, preferably 1.8: 1 to 10: 1, in particular 1.9: 1 to, for the entire reaction in step (a) 2.5: 1.
• the water formed in the sulfonation of phenol with sulfuric acid or phenolsulfonic acid can be continuously azeotropically distilled off from the reaction by means of excess phenol present in the reaction mixture and the phenol can be returned to the reactor after phase separation of the water.
• azeotropic distillation at least 50%, but better 90 to 100% of the amount of water which is formed according to the theory, no more phenol is generally returned to the reaction, but the phenol is gradually, advantageously at 160 ° C to 200 ° C distilled off.
• the unreacted phenol is used again in the next cycle of the manufacturing process.
• phenol is first largely reacted with the sulfonating agent to give phenolsulfonic acid in step (a), the water of reaction which may be formed is removed by distillation, then the phenolsulfonic acid is reacted with further phenol to give the dihydroxydiphenylsulfone and the water of reaction formed is again removed by distillation ,
• an isomerization phase of the reaction mixture at a temperature of usually 140 ° C. to 180 ° C., in particular 150 ° C. to 170 ° C., and an isomerization time of normally 0.1 to 10 hours, in particular 1 to 4 hours, on.
• the isomerization is generally catalyzed by small amounts of phenolsulfonic acid, which is usually still present in small amounts in the reaction mixture, especially when working with a slight stoichiometric excess of sulfonating agent.
• step (a) after the reaction of step (a) has been carried out, but as a rule before carrying out an isomerization phase, excess phenol is virtually completely removed by distillation.
• the reaction mixture was aerated with nitrogen and the temperature was gradually lowered from 165 ° C. to 140 ° C. within one hour. The mixture was then isomerized for a further 3 hours at this temperature.
• the crystals obtained were in 7200 ml of a mixture of water and acetone in vol. -Recrystallized from 90:10 at 80 ° C using activated carbon.
• the crystals were dissolved at 80 ° C., mixed with 3.2 g of commercially available activated carbon and stirred at this temperature. After clear filtration through a heated pressure filter, a colorless solution was formed. After cooling to 25 ° C, the colorless crystals were filtered off and washed twice with 200 g of water. 1031 g (4.1 mol, 95% based on freshly used phenol) of colorless pure crystallizate were obtained.

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

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• 2000
  • 2000-04-14 DE DE10018580A patent/DE10018580A1/de not_active Withdrawn
• 2001
  • 2001-04-10 DE DE50108671T patent/DE50108671D1/de not_active Expired - Lifetime
  • 2001-04-10 EP EP01927904A patent/EP1272462B1/de not_active Expired - Lifetime
  • 2001-04-10 AU AU54801/01A patent/AU5480101A/en not_active Abandoned
  • 2001-04-10 WO PCT/EP2001/004081 patent/WO2001079163A1/de not_active Ceased
  • 2001-04-10 US US10/257,328 patent/US6700020B2/en not_active Expired - Lifetime
  • 2001-04-10 JP JP2001576765A patent/JP4637438B2/ja not_active Expired - Lifetime

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