Abstract:
A process for preparing acrylic acid from methanol and acetic acid, comprising (i) contacting a gaseous stream S0 comprising methanol, oxygen and inert gas with an oxidation catalyst to obtain a gaseous stream S1 comprising formaldehyde and inert gas; (ii) removing at least a portion of the inert gas present in S1 from at least a portion of the formaldehyde present in S1 by absorbing this formaldehyde in an absorbent to obtain a gaseous stream S2 comprising the portion of the inert gas removed, and to obtain a stream S3 comprising absorbent and absorbate comprising formaldehyde; (iii) optionally removing a portion or the entirety of the absorbent present in stream S3, such that a stream S3a remains from stream S3, and producing a stream S4 from at least stream S3 or stream S3a and a stream S5 comprising acetic acid; and (iv) contacting stream S4 in gaseous form with an aldol condensation catalyst to obtain a gaseous stream S6 comprising acrylic acid.
Abstract:
The invention relates to a process for preparing acrylic acid from formaldehyde and acetic acid, comprising (i) providing a gaseous stream S1 comprising formaldehyde, acetic acid and acrylic acid, where the molar ratio of acrylic acid to the sum total of formaldehyde and acetic acid in stream S1 is in the range from 0.005:1 to 0.3:1; (ii) contacting stream S1 with an aldol condensation catalyst in a reaction zone to obtain a gaseous stream S2 comprising acrylic acid.
Abstract:
A process for preparing acrylic acid from formaldehyde and acetic acid, is performed by (i) providing a gaseous stream S1 comprising formaldehyde, acetic acid, oxygen and water, where the formaldehyde content of stream S1 is in the range from 8% to 18% by volume, based on the total volume of stream S1, the ratio of the volumes of acetic acid to formaldehyde is in the range from 0.6:1 to 1.1:1, and the molar ratio of oxygen to the total amount of organic carbon is in the range from 0.02:1 to 0.15:1; and (ii) contacting stream S1 with an aldol condensation catalyst in a reaction zone to obtain a gaseous stream S2 containing acrylic acid.
Abstract:
A process for obtaining acrylic acid, comprising (a) providing a liquid stream S7 comprising acetic acid and acrylic acid, where the molar ratio of acetic acid to acrylic acid in stream S7 is greater than 1:1, (b-1) crystallizing a portion of the acetic acid present in stream S7 to obtain solid crystallized acetic acid in its mother liquor, (b-2) separating the mother liquor from the acetic acid crystallized in (b-1) to obtain the solid crystallized acetic acid and a liquid stream S8 comprising acrylic acid and acetic acid, (c) separating stream S8 into at least one stream S10 depleted of acrylic acid compared to S8 and a stream S11 enriched in acrylic acid compared to S8.
Abstract:
The present invention relates to a process for preparing cyclohexane from methylcyclopentane (MCP) and benzene. In the context of the present invention, MCP and benzene are constituents of a hydrocarbon mixture (HM1) additionally comprising dimethylpentanes (DMP), possibly cyclohexane and possibly at least one compound (low boiler) selected from acyclic C5-C6-alkanes and cyclopentane. First of all, benzene is converted in a hydrogenation step to cyclohexane (that present in the hydrocarbon mixture (HM2)), while MCP is isomerized in the presence of a catalyst, preferably of an acidic ionic liquid, to cyclohexane. After the hydrogenation but prior to the isomerization the dimethylpentanes (DMP) are removed, with initial removal of the cyclohexane present in the hydrocarbon mixture (HM2) together with DMP. This cyclohexane already present prior to the isomerization can be separated again from DMP in a downstream rectification step and isolated and/or recycled into the process for cyclohexane preparation. Between the DMP removal and MCP isomerization—if low boilers are present in the hydrocarbon mixture (HM1)—low boilers are, optionally removed. After the isomerization, the cyclohexane is isolated, optionally with return of unisomerized MCP and optionally of low boilers. Preferably, cyclohexane and/or low boilers are present in the hydrocarbon mixture (HM1), and so a low boiler removal is preferably conducted between the DMP removal from isomerization. It is additionally preferable that the removal of the cyclohexane from DMP is additionally conducted, meaning that the cyclohexane component which arises in the benzene hydrogenation and may be present in the starting mixture (HM1) is isolated and hence recovered.
Abstract:
The present invention relates to a process for treating an output from a chemical reaction, wherein the chemical reaction is performed in the presence of an ionic liquid. The chemical reaction is preferably an isomerization. In a rectifying column with a partial condenser, the hydrogen halide is drawn off from a mixture which originates from the chemical reaction and comprises at least one organic compound, preferably at least one hydrocarbon, and at least one hydrogen halide.
Abstract:
The present invention relates to a process for isomerizing at least one hydrocarbon in the presence of an acidic ionic liquid and at least one hydrogen halide (HX) in an apparatus (V1), wherein the hydrogen halide (HX) is removed in an apparatus (V2) in gaseous form from the isomerization product and is at least partly recycled into apparatus (V1).