Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic System
  • C07F9/02—Phosphorus compounds
  • C07F9/06—Phosphorus compounds without P—C bonds
  • C07F9/08—Esters of oxyacids of phosphorus
  • C07F9/09—Esters of phosphoric acids
  • C07F9/11—Esters of phosphoric acids with hydroxyalkyl compounds without further substituents on alkyl
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic System
  • C07F9/02—Phosphorus compounds
  • C07F9/06—Phosphorus compounds without P—C bonds
  • C07F9/08—Esters of oxyacids of phosphorus
  • C07F9/09—Esters of phosphoric acids
  • C07F9/12—Esters of phosphoric acids with hydroxyaryl compounds

Definitions

• the invention relates to an improved ner driving for the technical production of phosphoric acid, in which the remaining amount.
• Phosphorus trihalide which is present in the starting material together with the phosphoroxyl alogenide, is mixed with a halogen in a reaction preceding the main reaction.
• phosphoric acid esters that are suitable for special applications, such as flame retardants and plasticizers in polyvinyl chlorides, polycarbonates, polyurethane foams and others, to name just a few. They also serve as extractants and as additives in various applications.
• the crude products of the phosphoric acid esters obtained are purified either by distillation or by alkali / water washes. The combination of both cleaning steps. may be used if the amount of by-products in the raw esters is so high that the effectiveness of the washes (formation of emulsifiers) is severely impaired.
• Phosphorus oxychloride is produced on an industrial scale in an exothermic reaction from phosphorus trichloride and oxygen: 2 PCl 3 + O 2 > 2 POCl 3
• the phosphorus atom in the phosphorus oxychloride is in the 5-valent oxidation state.
• the phosphorus atom in the incompletely converted starting material phosphorus trichloride (residual product in the technical POCl3 synthesis), however, is in the trivalent oxidation state and leads to the corresponding phosphorous acid esters in the reaction with aliphatic or aromatic alcohols. These are more unstable than the phosphoric acid esters.
• the phosphorous acid esters with moisture are subject to hydrolysis to form phosphorous acid (or its partial esters) and aliphatic or aromatic alcohols.
• phosphorous acid or its partial esters
• aliphatic or aromatic alcohols aliphatic or aromatic alcohols
• the phosphorous acid esters and the resulting phosphorous acid have a reducing effect. In some applications (e.g. in the photo sector), this property also proves to be annoying.
• the invention had for its object to provide an improved ner driving for the technical production of phosphoric triesters which avoids the formation of phosphoric acid esters and the associated disadvantages of post-acidification and odor formation.
• the invention relates to a technical process for the production of phosphoric acid, characterized in that
• the technical mixture used in the first step of the process consists essentially of phosphorus oxyhalide and phosphorus trichloride and further by-products such as pyrochlorophosphates, pyrochlorophosphites or phosphopentachloride.
• the preferred phosphorus oxyhalide is phosphorus oxychloride.
• the preferred phosphorus trihalide is phosphorus trichloride.
• halogens are chlorine and bromine. Chlorine is very particularly preferred.
• the halogen is preferably added to the starting material in the gaseous state under pressures of 30,000 Pa to 600,000 Pa, preferably from 250,000 Pa to 350,000 Pa, in an equimolar amount, based on the amount of phosphorus trihalide.
• the amount of phosphorus trihalide can be measured with a redox electrode based on its redox potential, for example. Overdoses should be avoided since side reactions such as chlorination or oxidation can occur which adversely affect the advantages of this invention become. To do this, it is necessary to determine the phosphorus trihalide content in the starting material.
• the halogenation can be carried out continuously, for. B. in loop or tube reactors - preferably in jet nozzle reactors - or discontinuously z. B. take place in stirred tanks by means of fumigation pipes.
• the phosphoric acid triesters can then be prepared according to known ner processes, but with the measure according to the invention that the halogen-treated starting material and the aliphatic and / or aromatic alcohols are passed into a reactor arrangement and the resulting crude mixtures are subjected to a distillative purification method under vacuum, preferably in several stages become.
• Aromatic phosphoric acid triesters are obtained with aromatic alcohols and aliphatic phosphoric acid triesters are obtained with aliphatic alcohols.
• pretreated starting material pretreated with halogen
• three times the molar amount of aromatic alcohols, based on phosphorus oxyhalide, and optionally catalysts, are increased by increasing
• Aromatic alcohols which can be used are those of the general formula (I)
• a straight-chain or branched alkyl radical having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, which may contain other substituents such as halogens, preferably fluorine and / or chlorine or alkoxy groups and / or
• halogens preferably bromine and / or chlorine and / or
• Aromatic alcohols such as phenols, cresols, ethylphenols, propylphenols, fluorophenols and methoxyphenols are preferred. Phenol, m-cresol and p-cresol or mixtures are very particularly preferred.
• Suitable catalysts are, are, for example aluminum, zinc and magnesium chlorides, magnesium phosphate or magnesium oxide, preferably magnesium chloride, magnesium phosphate or magnesium oxide, is particularly preferably magnesium oxide.
• pretreated starting material and 6 to 12 times the molar amount of aliphatic alcohols, based on phosphorus oxyhalide, are reacted at temperatures from -10 to 60 ° C., preferably from 5 to 45 ° C.
• Aliphatic alcohols which can be used are those of the general formula (II)
• Aliphatic alcohols such as methanol, ethanol,
• the hydrogen chloride released in the reactions is converted into hydrochloric acid by means of an absorption column.
• the raw products become
• the chlorinated hydrocarbons formed and the dissolved residual hydrogen chloride is subjected to a partial distillation in a reduced vacuum, i.e. with aromatic phosphoric acid tries under pressure from 300 to 800 Pa., with aliphatic phosphoric acid test under pressures from 2,000 to 4,000 Pa.
• the recovered aliphatic or aromatic alcohols are returned to the reaction.
• the bottoms of the partial distillation are subjected to fine distillation under high vacuum, i.e. with aromatic phosphoric acid tries at pressures from 10 to 1,000 Pa. with aliphatic phosphoric acid tries at pressures from 300 to 2,000 Pa.
• the bottom products including partial esters formed by acidolysis
• used catalysts are, if appropriate, worked up or released for disposal.
• the aromatic or aliphatic phosphoric triesters with a purity of 99.3% to 99.8% are in the distillate so that further cleaning methods (for example by washing) are no longer necessary.
• the higher purity of the products also results in further advantages due to the improved thermal stability.
• the products are anhydrous. In the context of the present invention, one understands water-free Water content less than 0.01%. When processing in plastics, no ester cleavage occurs under acid formation and alcohol / phenol cleavage due to the lack of residual water.
• the product triphenyl phosphate - produced by the process according to the invention - surprisingly produces a significantly improved so-called "raw tone" - as in the example
• Bayblend ® from Bayer.
• the solid triphenyl phosphate flash point: 50 ° C
• flash point 50 ° C
• the phosphoric triesters must be thermally stable to the extent that they can withstand distillation without decomposition. This requires previous tests, such as differential thermal analysis (DTA).
• DTA differential thermal analysis
• the distillative separations are carried out in vacuo at 3,000 to 10 Pa, preferably at
• corresponding known separation operations are selected, such as, for example, the use of distillation columns, thin-film evaporators, falling-film evaporators and / or combinations of the apparatus arrangements mentioned.
• Reaction of phosphorus trichloride with chlorine is spontaneous and exothermic. Due to the small amount of phosphorus trichloride, additional cooling is not necessary.
• the redox potential is measured by means of a redox electrode and the chlorine supply is regulated accordingly. Inert, gaseous components are discharged above the nozzle to prevent incorrect measurements due to bubble formation.
• the outlet of the reactor arrives in a collecting tank, in which chlorine gas can be replenished intermittently if there is underchlorination by means of a gassing tube.
• the mixture obtained serves as a pretreated starting material for the further phosphoric triester syntheses.
• the pretreated starting material in the collection template is examined for free chlorine: a sample is decomposed with water and neutralized with sodium hydrogen carbonate. The free chlorine is determined iodometrically (content 0.03% free chlorine).
• Example 1 13,200 g of melted phenol and 45 g of MgO as a catalyst are continuously fed to an electrically heatable 4-stage reaction cascade - provided with immersion tubes, thermometers, reflux coolers and exhaust pipes. Heating the cascade increases the temperature from approx. 120 ° C to approx. 300 ° C at the end of the cascade.
• the resulting hydrogen chloride is fed via a manifold to an absorption system from which hydrochloric acid is generated.
• the cascade drains into a collection container, which serves as a template for the subsequent 2-stage distillation of the raw product. In the first stage, the excess phenol is separated off at approx. 110 ° C / 500 Pa and used again in the reaction.
• the bottom effluent is fed to the 2nd distillation call, in which the main product, triphenylphosphate, is obtained at about 235 ° C / 600 Pa with a yield of over 95% (based on POCl 3 ) and the following data:
• the bottom portion consisting of Mg-phosphoric acid partial esters, is removed and partially reused as a complex catalyst.
• the acid number was determined by titration with 0.1 N potassium hydroxide solution - after previously adding methanol to the sample.
• the water content was determined according to the Karl Fischer method with a biometric erometric end point display using a device from Metrohm of the Titrino 720 KFS type. Before that, the sample was mixed with the hydranal solvent from Riedel de Haen.
• the melting range was determined using a Büschi 535 instrument.
• Free phenols were measured photometrically using a Cadas 30S spectrophotometer from Dr. Determined for a long time.
• the sample was extracted with methylene chloride and 0.1 N sodium hydroxide solution and the sodium phenolate formed was mixed with an acetic acid solution of p-nitroaniline and sodium nitrite and then with sodium carbonate.
• the Hazen color number is understood to mean the number of mg of platinum [from potassium hexachloroplatinate (IV) with cobalt ( ⁇ ) chloride hexahydrate in a ratio of 1.246: 1 dissolved in 1,000 ml of aqueous hydrochloric acid], which is (approximately) the same in the same layer thickness Color as the sample shows.
• Hazen color number was determined in the present invention according to ISO 6271.
• ISO 6271 is the color of a solution which contains 1 mg / 1 platinum as hexachloroplatinate ion and 2 mg / 1 Co-II chloride hexahydrate.
• the conductivity was determined using a Knick 702 device from Knick. 5 g of distilled product are stirred vigorously with 100 g of double distilled water for about 5 minutes. The conductance values (LW) of the aqueous phase and of the water are determined by conductometry.
• KMnO 4 test means a company-specific test in which 10 g of distilled product, 10 ml of 0.2 M KLMnO4 solution and 30 ml of acetone are shaken vigorously as a solubilizer. When standing for over 20 min
• test should be evaluated positively.
• the blank value is determined with acetone and peranganganate solution.
• Phenols take place in the 1st stage at approx. 110 ° C / 500 Pa and in the 2nd stage at approx.
• Exhaust line 690 g / h of starting material (from Example 1) and 3,350 g / h dry n-butanol are continuously introduced.
• the temperature is kept at 5 - 10 ° C.
• the overflow from the reactor reaches four coolable indwelling vessels connected in series with immersion tubes,. Thermometer and exhaust pipes. The temperature gradually increases to 35 ° C using cooling
• Retention vessel increased.
• the hydrogen chloride formed from the reactor and the holding vessels is converted into hydrochloric acid in a connected absorption column.
• the outlet from the indwelling vessel is passed into a collecting container, which serves as a template for a degassing column.
• the more volatile constituents - such as dissolved hydrogen chloride - become excess
• the condensate is washed with water and separated into organic and aqueous phases in a settling arrangement.
• the butyl chloride is enriched from the organic phase by stripping using a stripping column.
• the recovered butanol is returned to the reaction after drying.
• the bottom discharge of approx. 180 ° C is subjected to gentle distillation at 148 ° C / 1,000 Pa, which is combined with a thin-film evaporator.
• the yield is over 92% (based on POCl 3 ) with the following data.
• Example 4 765 g / h of starting material (according to Example 1) and 2,070 g / h of dry ethanol are reacted.
• the reactor temperature is kept at 0-5 ° C.
• the temperatures in the indwelling vessels are increased to 30 ° C.
• the temperatures at the outgassing column are 14 ° C / 3,000 Pa at the top and 118 ° C in the bottom.
• the crude product is distilled at 83 ° C / 1,000 Pa and in the bottom at 141 ° C.
• the yield of triethyl phosphate is over 92% (based on POCl 3 ) with the following data:

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• 2002
  • 2002-05-28 DE DE2002123649 patent/DE10223649C1/de not_active Expired - Lifetime
• 2003
  • 2003-05-26 WO PCT/EP2003/005461 patent/WO2003100073A2/de not_active Application Discontinuation
  • 2003-05-26 AU AU2003233342A patent/AU2003233342A1/en not_active Abandoned

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