Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D301/00—Preparation of oxiranes
  • C07D301/02—Synthesis of the oxirane ring
  • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
  • C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
  • C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D301/00—Preparation of oxiranes
  • C07D301/02—Synthesis of the oxirane ring
  • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
  • C07D301/14—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with organic peracids, or salts, anhydrides or esters thereof

Definitions

• the invention relates to a process for the preparation of epoxides by gas phase oxidation of hydrocarbons with olefinic double bonds by means of a heterogeneously catalyzed reaction, which can be used in particular in the chemical industry.
• propene oxide is currently produced indirectly in the liquid phase, in particular by the chlorohydrin process or by oxidation with hydroperoxides.
• the chlorohydrin process leads to large chlorine losses in the form of worthless CaCl 2 or NaCl solutions that pollute the environment.
• Oxidation with hydroperoxides leads to large amounts of coproducts such as, for example, styrene or tert-butanol, which adversely affect the economics of the process [Industrial Organic Chemistry, ibid., Pp. 291-297; Ullmann's Encyclopedia of Industrial Chemistry, 5 ⁇ ed, VCH Verlag, Weinheim, 1993, Vol A22, pages 239-251.
• Patent WO 98/30552 describes a process for the oxidation of propene on a Silver-gold catalyst described.
• a disadvantage of the invention is that propene oxide selectivity of 50% is only possible with low propene conversions of 2%.
• Another disadvantage of this invention lies in the use of large amounts of carbon dioxide as a promoter for the reaction (the recommended one Concentration in the reactant gas is given as 5-25%)
• Patents WO 98/00413, WO 98/00414 and WO 98/00415 describe processes for the oxidation of propene in the gas phase over a gold catalyst.
• a disadvantage of the inventions is that only low yields of propene oxide can be achieved.
• Another disadvantage The invention also lies in the fact that the economics of the process are impaired by the use of an expensive catalyst
• the aim of the invention is to eliminate the disadvantages described and to develop a technologically simple process which enables the heterogeneously catalyzed partial oxidation of hydrocarbons with olefinic double bonds to epoxides with relatively high conversions and selectivities, the catalyst used being characterized by high long-term activity and -Stability, abrasion resistance and regenerability
• the invention is based on the object of developing a process which, through the use of an inexpensive solid catalyst and a gaseous oxidizing agent, leads to the epoxidation of hydrocarbons with olefinic double bonds, in particular alkenes such as propene, in the gas phase with high epoxide selectivities
• the object is achieved in that the solid catalyst is based on an oxidic support, in particular silicon dioxide (SiO 2 ), contains iron oxide as active component and synergistically complementary as promoters Elements from group 1 and / or group 2 of the periodic table of the elements are included. It has been shown to be advantageous that the active component with an iron content between 0.001% and 1% is uniformly and homogeneously distributed on and / or in the carrier and that the carrier has a specific surface area of more than 50 m 2 / g.
• the promoter in particular sodium ions
• the “green” catalyst prepared in this way is ready for use by calcining at a temperature between 300-1000 ° C.
• a pure or an Na-promoted oxidic carrier, in particular SiO 2 shows no or only very little activity and selectivity for the epoxidation of hydrocarbons with olefinic double bonds and, according to the invention, the presence of iron on and / or in the matrix of the oxidic support, in particular SiO 2 , is decisive for the catalytic activity and selectivity in the epoxidation reaction.
• nitrous oxide is used according to the invention in concentrations of 5% to 99%.
• nitrogen, helium or alkanes are used as the inert gas.
• the reaction is carried out in a temperature range of 300-500 ° C. at space velocities of 1-20 lh gK at '1 , so that, according to the invention, the conversions of 2-30% of the epoxide selectivity are between 10-70%.
• the catalyst according to the invention loses its activity only insignificantly during the reaction, so that it only needs to be reactivated after 5-20 hours of operation by "burning off" in air or in another oxygen-containing gas. It is also noteworthy that after more than 50 reactivation cycles the catalyst is highly active, mechanically stable and abrasion resistant.
• a commercial silica gel with an Fe content of 0.0100% and a specific surface area of 484 m 2 / g was impregnated with an aqueous solution containing 10 "3 mol / 1 sodium acetate with occasional stirring. After filtration and washing With distilled water, the silica gel impregnated with Na ions was added in the first stage for 5 hours Calcined at 600 ° C. In the second stage, the catalyst was calcined at 700 ° C. for an additional 6 h.
• the catalyst prepared in this way was used for the oxidation reaction in a flow apparatus in a quartz tube reactor.
• the reaction products were determined on-line by gas chromatography and IR photometry and quantified.
• an educt current composition of 1% propene, 15% N 2 O and 84% He and a space velocity of 2 lh gKat "1 After an operating time of 80 min at a reaction temperature of 400 ° C, a propene conversion rate of 11% and a propene oxide selectivity of 18
• the by-products consisted mainly of propanal, acetone, acrolein and carbon oxides.
• a commercial silica gel with an Fe content of 0.0080% and a specific surface area of 309 m 2 / g was impregnated with a 10 "3 molar aqueous sodium acetate solution for 48 hours at room temperature with occasional stirring. After filtration and washing with distilled water the filter cake was dried and calcined in the first stage for 5 hours at 500 ° C. In the second calcining stage, the catalyst was treated for 6 hours at 800 ° C.
• the catalyst produced in this way was used in the quartz reactor of the flow apparatus according to embodiment 1 and tested under the same conditions as in example 1. It was found that a degree of propene conversion of 4.5% is achieved and the propene oxide selectivity increased to 23%. Mainly propanal, acetone, acrolein and carbon oxides were formed as by-products.
• the catalyst was used in the flow apparatus for the oxidation reaction, according to embodiment 1.
• an educt stream composition of 1% propene, 15% N 2 O and 84% He and a space velocity of 2 ll '.gKat "1 a conversion rate of propene of 5% and a selectivity to propene oxide was achieved at 350 ° C. after 130 minutes of operation of 60% with the same starting material composition and space velocity at 375 ° C after 130 min or 330 min and 680 min operating time, conversion rates of 8.7 or 6.0 and 4.3% and selectivities of 49.6 or 51.8 and 48.1% were determined.
• a silica sol was prepared from tetraethyl orthosilicate (0.3 mol), ethanol (1.95 mol), i-propanol (0.3 mol), 1-dodecylamine (0.09 mol) and water (10.8 mol) was left to gel for 48 h at room temperature.
• a chemically pure silica gel with a specific surface area of 1167 m 2 / g was obtained by drying and calcining at 600 ° C. for 5 hours.
• the silica gel was enriched with an amount of Fe up to an Fe concentration of 0.0100% and then promoted with Na ions. After calcining at 700 ° C. for 6 hours, the catalyst was inserted into the reaction apparatus according to embodiment 1. With a reactant stream composition of 1% propene, 40% N 2 O and 59% He, a space velocity of 2 a degree of conversion of propene of 5% and a selectivity to propene oxide of 44% were determined at 375 ° C. after 51 minutes of operation. The by-products correspond to those of Example 1.
• a commercial mixed oxide catalyst support composed of 97% SiO 2 and 3% TiO 2 was impregnated with an Fe (III) acetylacetonate-containing toluene solution in accordance with embodiment 3 using the "incipient wetness” method, so that the Fe content after the calcination (5 hours at 600 ° C.) 0.03%.
• This catalyst was then treated with an aqueous solution containing 10 "1 mol / 1 sodium acetate, filtered, washed and calcined at 700 ° C. for 6 hours by the method described in Example 1.
• the iron oxide-containing catalyst produced in this way showed in the flow apparatus with a starting material composition according to exemplary embodiment 1 and a space velocity of 4 at a reaction temperature of 400 ° C after 76 minutes of operation, a propene conversion of 5.6% and a propene oxide selectivity of 7.7%.
• the main by-products were propanal, acetone, acrolein and carbon oxides.
• a commercial silica gel with an Fe content of 0.0006% was impregnated with a toluene solution containing Fe (III) acetylacetonate by the "incipient wetness" method, so that the Fe content of the sample after the calcination (5th h at 0.03% at 600 ° C.
• This catalyst was then treated with an aqueous solution containing 0J mol / l of sodium acetate, filtered, washed and calcined at 700 ° C. for 6 hours by the method described in Example 1.
• the catalyst was used for the partial oxidation of 1-butene in a flow apparatus according to embodiment 1.
• a flow apparatus according to embodiment 1.
• a butenumsatzgrad of 28.8% and 23.8%
• a Butenoxidselektterrorism of 14J% or 15.7% were determined.
• organic by-products still produced approx. 5% carbon oxides.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Epoxy Compounds (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)

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• 1998
  • 1998-11-26 DE DE19854615A patent/DE19854615C2/de not_active Expired - Fee Related
• 1999
  • 1999-11-25 BR BR9907251-3A patent/BR9907251A/pt not_active IP Right Cessation
  • 1999-11-25 WO PCT/EP1999/009131 patent/WO2000031056A1/fr not_active Application Discontinuation
  • 1999-11-25 DE DE59901297T patent/DE59901297D1/de not_active Expired - Lifetime
  • 1999-11-25 KR KR1020007008093A patent/KR20010040401A/ko not_active Application Discontinuation
  • 1999-11-25 US US09/582,632 patent/US6392065B1/en not_active Expired - Fee Related
  • 1999-11-25 CN CN99802395A patent/CN1296479A/zh active Pending
  • 1999-11-25 AT AT99964503T patent/ATE216697T1/de not_active IP Right Cessation
  • 1999-11-25 EP EP99964503A patent/EP1056735B1/fr not_active Expired - Lifetime

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