摘要:
The invention relates to a process for preparing trioxane and at least one comonomer for preparing (co)polymers based on trioxane, in which, in a first step, formaldehyde the at least one comonomer reactant are reacted in aqueous solution to give trioxane and comonomer, to obtain a reaction mixture A1 comprising trioxane, comonomer, formaldehyde and water, with or without comonomer reactant. In a second step, the reaction mixture A1 is distilled in a first distillation stage at a first pressure to obtain a stream B1 enriched in trioxane and comonomer and a stream B2 comprising essentially water and formaldehyde, with or without comonomer reactant. In a third step, stream B1 is distilled in a second distillation stage at a pressure which is above the pressure of the first distillation stage to obtain a stream C1 comprising trioxane, comonomer and water and a product stream C2 consisting essentially of comonomer and trioxane.
摘要:
Processes are disclosed comprising: (a) reacting an aqueous formaldehyde solution in a reactor in the presence of a suitable catalyst to obtain a reaction product mixture comprising trioxane, formaldehyde and water; (b) distilling the reaction product mixture to form a top stream comprising crude trioxane; and (c) treating the top stream in one or more additional stages to form pure trioxane; wherein an aqueous sidestream is drawn off during the distilling of the reaction mixture.
摘要:
Processes comprising: providing a reactive distillation column having an upper region, a middle region and a lower region; feeding ethylene glycol and an aqueous formaldehyde solution into the reactive distillation column in the middle region of the reactive distillation column; reacting the ethylene glycol and the aqueous formaldehyde solution in the reactive distillation column in the presence of a catalyst to form dioxolane; removing a product stream comprising dioxolane in an amount of at least 75% by weight from the upper region of the reactive distillation column; and removing a bottom stream comprising one or more components having boiling points higher than dioxolane from the lower region of the reactive distillation column.
摘要:
The present invention relates to a process for distillatively removing pure trioxane from a feedstream (I) comprising trioxane in a proportion of at least 50% by weight, based on the total weight of the feedstream (I), and additionally formaldehyde and water, which comprises feeding the feedstream I and a further aqueous stream (II) which does not contain any components extraneous to the feedstream to a dividing wall column (TWK1) having a dividing wall TW which is arranged substantially perpendicularly and divides the column interior into a feed region (A1), a withdrawal reaction (B1), an upper combined column region (C1) and a lower combined column region (D1), and drawing off from the first dividing wall column (TWK1) a bottom stream (III) comprising pure trioxane and a sidestream (IV) at the withdrawal region (B1), comprising pure water.
摘要:
A process for removing trioxane from a mixture I of formaldehyde, trioxane and water, by a) distilling the mixture I in a first distillation stage at a pressure of from 0.1 to 2 bar to obtain a stream II which comprises formaldehyde and a stream III which comprises predominantly trioxane and additionally water and formaldehyde, b) mixing the stream III with a recycle stream VII which comprises predominantly trioxane and additionally water and formaldehyde to obtain a stream IIIa which comprises predominantly trioxane and additionally water and formaldehyde, c) distilling the stream IIIa, if appropriate after removing low boilers from the stream III or IIIa in a further distillation stage, in a second distillation stage at a pressure of from 0.2 to 10 bar, the pressure in the second distillation stage being at least 0.1 bar higher than the pressure in the first distillation stage, to obtain a stream IV of trioxane and a stream V which comprises predominantly trioxane and additionally water and formaldehyde, d) distilling the stream V in a third distillation stage at a pressure of from 0.1 to 4 bar to obtain a stream VI which comprises predominantly water and additionally formaldehyde, and the recycle stream VII which comprises predominantly trioxane and additionally water and formaldehyde, e) if appropriate, distilling the stream VI in a fourth distillation stage to obtain a stream VIII which comprises predominantly water, and a stream IX which comprises predominantly formaldehyde.
摘要:
The invention relates to an integrated process for preparing trioxane from formaldehyde in which a stream A1 comprising water and formaldehyde and a recycle stream B2 consisting substantially of water and formaldehyde are fed to a trioxane synthesis reactor in which the formaldehyde is converted to trioxane to obtain a product stream A2 comprising trioxane, water and formaldehyde; stream A2 is fed to a first distillation column and distilled at a pressure in the range from 0.1 to 2.5 bar to obtain a stream B1 enriched in trioxane, and the stream B2 consisting substantially of water and formaldehyde; stream B1 and a recycle stream D1 comprising trioxane, water and formaldehyde are fed to a second distillation column and distilled at a pressure in the range from 0.2 to 17.5 bar to obtain a product stream C2 consisting substantially of trioxane, and a stream C1 comprising trioxane, water and formaldehyde; stream C1 is fed to a third distillation column and distilled at a pressure in the range from 0.1 to 2.5 bar to obtain the recycle stream D1 comprising trioxane, water and formaldehyde, and a stream D2 consisting substantially of water and formaldehyde.
摘要:
The invention relates to an integrated process for preparing trioxane from formaldehyde, comprising the steps of: a) a stream A1 comprising water and formaldehyde and a recycle stream B2 consisting substantially of water and formaldehyde are fed to a trioxane synthesis reactor and allowed to react to obtain a product stream A2 comprising trioxane, water and formaldehyde; b) stream A2 is fed to a first low-pressure distillation column and distilled at a pressure of from 0.1 to 2.5 bar to obtain a stream B1 enriched in trioxane and additionally comprising water and formaldehyde, and the recycle stream B2 consisting substantially of formaldehyde and water; c) stream B1 and a recycle stream D1 comprising trioxane, water and formaldehyde are fed to a second low-pressure distillation column and distilled at a pressure of from 0.1 to 2.5 bar to obtain a stream C1 comprising predominantly trioxane and additionally formaldehyde and water, and a stream C2 consisting substantially of formaldehyde and water; d) stream C1 is fed to a high-pressure distillation column and distilled at a pressure of from 0.2 to 17.5 bar to obtain the recycle stream D1 and a product stream D2 consisting substantially of trioxane, in which a removal of the low boilers present in streams B1 or C1 may be undertaken between steps b) and c) or c) and d).
摘要:
A process for removing trioxane from a use stream I of formaldehyde, trioxane and water, by a) providing a use stream I which comprises formaldehyde as the main component and trioxane and water as the secondary components, b) mixing the use stream I with a recycle stream VII which comprises trioxane as the main component and formaldehyde and water as the secondary components to obtain a feed stream Ia which comprises formaldehyde as the main component and trioxane and water as the secondary components, c) distilling the use stream Ia in a first distillation stage at a pressure of from 0.1 to 2.5 bar to obtain a stream II which comprises formaldehyde as the main component and water as the secondary component, and a stream III which comprises trioxane as the main component and water and formaldehyde as the secondary components, d) distilling the stream III, optionally after removing low boilers from the stream III in a low boiler removal stage, in a second distillation stage at a pressure of from 0.2 to 17.5 bar, the pressure in the second distillation stage being from 0.1 to 15 bar higher than the pressure in the first distillation stage, to obtain a stream IV which consists substantially of trioxane and a stream V which comprises trioxane as the main component and water and formaldehyde as the secondary components, e) optionally mixing the stream V with a stream IX which comprises water as the main component to obtain a stream Va having a higher water content than the stream V, the stream Va comprising trioxane as the main component and water and formaldehyde as the secondary components, f) distilling the stream V or Va in a third distillation stage at a pressure of from 1 to 10 bar to obtain a stream VI which consists substantially of water and the recycle stream VII which comprises trioxane as the main component and water and formaldehyde as the secondary components
摘要:
Processes comprising: providing a reactive distillation column having an upper region, a middle region and a lower region; feeding ethylene glycol and an aqueous formaldehyde solution into the reactive distillation column in the middle region of the reactive distillation column; reacting the ethylene glycol and the aqueous formaldehyde solution in the reactive distillation column in the presence of a catalyst to form dioxolane; removing a product stream comprising dioxolane in an amount of at least 75% by weight from the upper region of the reactive distillation column; and removing a bottom stream comprising one or more components having boiling points higher than dioxolane from the lower region of the reactive distillation column.
摘要:
The invention relates to an integrated process for preparing trioxane from formaldehyde in which, in a first step, a stream A1 comprising water and formaldehyde and a recycle stream B2 consisting substantially of water and formaldehyde are fed to a trioxane synthesis reactor in which the formaldehyde is converted to trioxane to obtain a product stream A2 comprising trioxane, water and formaldehyde. Stream A2 and a recycle stream D1 comprising trioxane, water and formaldehyde are fed to a first distillation column and distilled at a pressure in the range from 0.1 to 2.5 bar to obtain a stream B1 enriched in trioxane, and the stream B2 consisting substantially of water and formaldehyde. Stream B1 is fed to a second distillation column and distilled at a pressure in the range from 0.2 to 17.5 bar to obtain a product stream C2 consisting substantially of trioxane, and a stream C1 comprising trioxane, water and formaldehyde. Stream C1 is fed to a third distillation column and distilled at a pressure in the range from 1 to 10 bar to obtain the recycle stream D1 comprising trioxane, water and formaldehyde, and a stream D2 consisting substantially of water.