摘要:
In a process for partially oxidizing acrolein to acrylic acid in the gas phase under heterogeneous catalysis, the starting reaction gas mixture is oxidized at an acrolein loading of ≦145 and ≧70 l (STP) of acrolein/l of fixed catalyst bed·h over a fixed catalyst bed which is accommodated in two successive reaction zones A, B, the highest temperature of the reaction gas mixture within reaction zone A being above the highest temperature of the reaction gas mixture within reaction zone B.
摘要:
A process for the heterogeneously catalyzed gas-phase partial oxidation of an organic compound over a fixed catalyst bed present in a fixed-bed reactor having a plurality of catalyst tubes, in which the reduction of the quality of the catalyst load with increasing duration of operation is restored by a partial catalyst change, is described.
摘要:
A process for the long-term operation of a heterogeneously catalyzed gas phase partial oxidation of acrolein to acrylic acid, in which the temperature of the fixed catalyst bed is increased over time and partial oxidation is interrupted and an oxygen-containing gas is conducted through the fixed catalyst bed before the temperature increase is 8° C.
摘要:
In a process for partially oxidizing propene to acrylic acid in the gas phase under heterogeneous catalysis, a starting reaction gas mixture comprising propene and oxygen and having a specific composition is oxidized in a first reaction stage over a first fixed catalyst bed having a volume-specific activity which is constant or increases in the flow direction and the acrolein-containing product gas mixture of the first reaction stage is subsequently oxidized in a second reaction stage over a second fixed catalyst bed having a volume-specific activity increasing in the flow direction, and the shaped catalyst bodies of both fixed catalyst beds are annular and each have a specific multimetal oxide composition.
摘要:
In a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrylic acid, the starting reaction gas mixture is oxidized at a propene loading of
摘要:
A process for preparing (meth)acrolein and/or (meth)acrylic acid by heterogeneously catalyzed gas phase partial oxidation of an organic precursor compound over a fresh fixed catalyst bed, in which the process is started up at a reduced hourly space velocity of charging gas mixture on the fixed catalyst bed.
摘要:
A process for removing methacrylic acid from liquid phase P comprising acrylic acid as a main constituent and target product, and methacrylic acid as a secondary component in which the removal is effected by crystallization, the acrylic acid accumulating in the crystals formed and the methacrylic acid in the remaining mother liquor.
摘要:
A process for preparing a multimetal oxide material which contains the elements Mo, V and Te and/or Sb and at least one of the elements Nb, Ti, W, Ta and Ce and if desired promoters and has a specific X-ray diffraction pattern, in which process the last process step comprises washing with acidic liquids. In addition, a multimetal oxide material obtainable in such a way is used as a catalyst for heterogeneously catalyzed gas-phase partial oxidations and/or ammoxidation of hydrocarbons.
摘要:
A process for long-term operation of a continuous heterogeneously catalyzed partial dehydrogenation of a hydrocarbon to be dehydrogenated, in which a reaction gas mixture stream comprising the hydrocarbon to be dehydrogenated in a molar starting amount KW is conducted through an overall catalyst bed comprising the total amount M of dehydrogenation catalyst and the deactivation of the overall catalyst bed is counteracted in such a way that, with increasing operating time, the contribution to the conversion in the first third of the total amount M of dehydrogenation catalyst in flow direction decreases, the contribution to the conversion in the last third of the total amount M of dehydrogenation catalyst in flow direction increases, and the contribution to the conversion in the second third of the total amount M of dehydrogenation catalyst in flow direction passes through a maximum.
摘要:
A process for regenerating a catalyst bed deactivated in the course of a heterogeneously catalyzed partial dehydrogenation of a hydrocarbon, in which a gas comprising molecular oxygen is conducted at elevated temperature through the deactivated catalyst bed and, in the course of the regeneration, the content of molecular oxygen in the regeneration gas is increased repeatedly and the increase in the carbon oxide content of the regeneration gas as it flows through the deactivated catalyst bed is restricted to values of ≦5% by volume.