Abstract: An aqueous solution comprising acrylic acid and the conjugate base thereof in a total amount of at least 10% by weight, based on the weight of the aqueous solution, and propionic acid and the conjugate base thereof, formic acid and the conjugate base thereof, acetic acid and the conjugate base thereof, benzoic acid and the conjugate base thereof, maleic anhydride, maleic acid and the conjugate bases thereof, phthalic anhydride, phthalic acid and the conjugate bases thereof, acrolein, benzaldehyde, 2-furaldehyde, and at least 20 mol % of at least one alkali metal cation; process for preparing this solution; and the use of this solution for preparation of polymer by free-radical polymerization.

Abstract: An aqueous solution comprising acrylic acid and the conjugate base thereof in a total amount of at least 10% by weight, based on the weight of the aqueous solution, and propionic acid and the conjugate base thereof, formic acid and the conjugate base thereof, acetic acid and the conjugate base thereof, benzoic acid and the conjugate base thereof, maleic anhydride, maleic acid and the conjugate bases thereof, phthalic anhydride, phthalic acid and the conjugate bases thereof, acrolein, benzaldehyde, 2-furaldehyde, and at least 20 mol % of at least one alkali metal cation; process for preparing this solution; and the use of this solution for preparation of polymer by free-radical polymerization.

Abstract: A process for preparing acrylic acid from methanol and acetic acid, in which, in a reaction zone A, the methanol is partially oxidized to formaldehyde in a heterogeneously catalyzed gas phase reaction, the product gas mixture A obtained and an acetic acid source are used to obtain a reaction gas input mixture B which comprises acetic acid and formaldehyde and has the acetic acid in excess over the formaldehyde, and the formaldehyde present in reaction gas input mixture B is aldol-condensed to acrylic acid under heterogeneous catalysis in a reaction zone B with acetic acid present in reaction gas input mixture B, and unconverted acetic acid still present alongside the acrylic acid target product in the product gas mixture B obtained is removed therefrom, and the acetic acid removed is recycled into the production of reaction gas input mixture B.

Abstract: A process for preparing acrylic acid from ethanol and formaldehyde, in which, in a reaction zone A, the ethanol is partially oxidized to acetic acid in a heterogeneously catalyzed gas phase reaction, the product gas mixture A obtained and a formaldehyde source are used to obtain a reaction gas input mixture B which comprises acetic acid and formaldehyde and has the acetic acid in excess over the formaldehyde, and the formaldehyde present in reaction gas input mixture B is aldol-condensed with acetic acid present in reaction gas input mixture B to acrylic acid under heterogeneous catalysis in a reaction zone B, and unconverted acetic acid still present along-side the acrylic acid target product in the product gas mixture B obtained is removed therefrom, and the acetic acid removed is recycled into the production of reaction gas input mixture B.

Abstract: A process for preparing acrylic acid from ethanol and formaldehyde, in which, in a reaction zone A, the ethanol is partially oxidized to acetic acid in a heterogeneously catalyzed gas phase reaction, the product gas mixture A obtained and a formaldehyde source are used to obtain a reaction gas input mixture B which comprises acetic acid and formaldehyde and has the acetic acid in excess over the formaldehyde, and the formaldehyde present in reaction gas input mixture B is aldol-condensed with acetic acid present in reaction gas input mixture B to acrylic acid under heterogeneous catalysis in a reaction zone B, and unconverted acetic acid still present along-side the acrylic acid target product in the product gas mixture B obtained is removed therefrom, and the acetic acid removed is recycled into the production of reaction gas input mixture B.

Abstract: An aqueous solution containing 10% by weight of acrylic acid and its conjugate base. The solution further contains, based on the amount of acrylic acid and its conjugate base: at least 50 ppm of propionic acid and its conjugate base; at least 200 ppm of formic acid and its conjugate base; at least 3000 ppm of acetic acid and it conjugate base; at most 10 ppm of benzoic acid and its conjugate base; at most 10 ppm of maleic anhydride, maleic acid, and their conjugate bases; at most 10 ppm of phthalic anhydride, phthalic acid, and their conjugate bases; at most 50 ppm of acrolein; at most 50 ppm of benzaldehyde; at most 50 ppm of 2-furaldehyde; and at least 20 mol % of at least one alkali metal cation. A process for preparing this solution and the use of this solution for preparation of a polymer by free-radical polymerization.

Abstract: A process for preparing acrylic acid from ethanol and formaldehyde, in which, in a reaction zone A, the ethanol is partially oxidized to acetic acid in a heterogeneously catalyzed gas phase reaction, the product gas mixture A obtained and a formaldehyde source are used to obtain a reaction gas input mixture B which comprises acetic acid and formaldehyde and has the acetic acid in excess over the formaldehyde, and the formaldehyde present in reaction gas input mixture B is aldol-condensed with acetic acid present in reaction gas input mixture B to acrylic acid under heterogeneous catalysis in a reaction zone B, and unconverted acetic acid still present along-side the acrylic acid target product in the product gas mixture B obtained is removed therefrom, and the acetic acid removed is recycled into the production of reaction gas input mixture B.

Abstract: A process for preparing acrylic acid from methanol and acetic acid, in which, in a reaction zone A, the methanol is partially oxidized to formaldehyde in a heterogeneously catalyzed gas phase reaction, the product gas mixture A obtained and an acetic acid source are used to obtain a reaction gas input mixture B which comprises acetic acid and formaldehyde and has the acetic acid in excess over the formaldehyde, and the formaldehyde present in reaction gas input mixture B is aldol-condensed to acrylic acid under heterogeneous catalysis in a reaction zone B with acetic acid present in reaction gas input mixture B, and unconverted acetic acid still present alongside the acrylic acid target product in the product gas mixture B obtained is removed therefrom, and the acetic acid removed is recycled into the production of reaction gas input mixture B.