Abstract:
The invention relates to a process for preparing isocyanates by reacting primary amines with phosgene in a solvent, where the solvent comprises a dialkyl carbonate.
Abstract:
The present invention relates to a process for preparing dioxolane by reacting ethylene glycol with an aqueous solution of formaldehyde in the presence of an acid catalyst. The raw product comprising water, dioxolane and methanol is fed to a phase separation unit (20) wherein an organic extracting agent is present. An organic fraction stream from the phase separation unit is transferred to an upper part of a purification column (30) from which dioxolane is withdrawn as a bottom product while the distillate stream of the purification column is recycled to the phase separation unit. An aqueous fraction stream from the phase separation unit is transferred to a waste water column (40), withdrawing a waste water stream from the bottom of the waste water column, recycling a distillate stream (42) from the waste water column to the phase separation unit, and withdrawing a side stream (43) containing methanol from a stage below the feed stage of the waste water column.
Abstract:
The invention relates to a process for preparing isocyanates by reacting primary amines with phosgene in a solvent, where the solvent comprises a dialkyl carbonate.
Abstract:
The present invention relates to a process for preparing dioxolane by reacting ethylene glycol with an aqueous solution of formaldehyde in the presence of an acid catalyst. The raw product comprising water, dioxolane and methanol is fed to a phase separation unit (20) wherein an organic extracting agent is present. An organic fraction stream from the phase separation unit is transferred to an upper part of a purification column (30) from which dioxolane is withdrawn as a bottom product while the distillate stream of the purification column is recycled to the phase separation unit. An aqueous fraction stream from the phase separation unit is transferred to a waste water column (40), withdrawing a waste water stream from the bottom of the waste water column, withdrawing a side stream (42) from a stage between the feed stage and the reflux stage of the waste water column and recycling this stream (42) to the phase separation unit, and withdrawing a distillate stream (43) containing methanol from the waste water column.
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.