摘要:
A liquid mixture comprising at least one readily volatile and at least one sparingly volatile component is separated in a film evaporator by a process in which (i) a continuous stream of a liquid starting material mixture is provided, (ii) a liquid film is produced from the continuous stream and is brought into contact with a heat exchange surface of the Mm evaporator, (ii) the liquid film is partly evaporated, a gas stream enriched with the at least one readily volatile component and a liquid stream enriched with the at least one sparingly volatile component being obtained, wherein (iv) the heat exchange surface is coated with a catalytically active material which (v) catalyzes, in the liquid film, a chemical reaction in which at least one readily volatile component is formed.
摘要:
A liquid mixture comprising at least one readily volatile and at least one sparingly volatile component is separated in a film evaporator by a process in which (i) a continuous stream of a liquid starting material mixture is provided, (ii) a liquid film is produced from the continuous stream and is brought into contact with a heat exchange surface of the Mm evaporator, (ii) the liquid film is partly evaporated, a gas stream enriched with the at least one readily volatile component and a liquid stream enriched with the at least one sparingly volatile component being obtained, wherein (iv) the heat exchange surface is coated with a catalytically active material which (v) catalyzes, in the liquid film, a chemical reaction in which at least one readily volatile component is formed.
摘要:
Process for preparing high-concentration gaseous formaldehyde having a molar CH2O:H2O ratio of ≧0.6 from an aqueous formaldehyde solution by evaporation of at least part of the solution, in which the aqueous formaldehyde solution is heated to a vaporization temperature T and the gas phase formed is taken off, wherein the evaporation temperature T obeys the relationship: T[° C.]≧T′min[° C.] where T′min(c)=A+B×(c/100)+C×(c/100)2+D×(c/100)3 and A=+68.759, B=+124.77, C=−12.851, D=−10.095, where c is the instantaneous CH2O content of the aqueous formaldehyde solution during the evaporation in percent by weight and is from 20 to 99% by weight.
摘要:
Process for preparing high-concentration formaldehyde solutions having a CH2O content of ≧50% by weight from an aqueous formaldehyde solution having a lower CH2O content by evaporation of part of this solution (partial evaporation), in which the aqueous formaldehyde solution is heated to an evaporation temperature T at which the gas phase becomes enriched in water relative to the liquid phase and the gas phase formed is taken off continuously or discontinuously, wherein the evaporation temperature T obeys the relationship: T[° C.]
摘要:
A process for preparing trioxane from trioxymethylene glycol dimethyl ether (POMDMEn=3) by converting trioxymethylene glycol dimethyl ether in the presence of an acidic catalyst and subsequent distillative workup of the reaction mixture, comprising the steps of: a) feeding trioxymethylene glycol dimethyl ether (POMDMEn=3) or a mixture comprising trioxymethylene glycol dimethyl ether into a reactor and converting it in the presence of an acidic catalyst to a mixture a comprising trioxane, formaldehyde, water, methylene glycol (MG), polyoxymethylene glycols (MGn>1), methanol, hemiformals (HF), methylal (POMDMEn=1) and polyoxymethylene glycol dimethyl ethers (POMDMEn>1); b) distillatively separating the reaction mixture a into a low boiler fraction b1 comprising formaldehyde, water, methylene glycol, methanol, hemiformal (HFn=1), methylal and dioxymethylene glycol dimethyl ether (POMDMEn=2), and a high boiler fraction b2 comprising trioxane, polyoxymethylene glycols (MGn>1), hemiformals (HFn>1) and polyoxymethylene glycol dimethyl ethers (POMDMEn>2); c) distillatively separating the high boiler fraction b2 into a low boiler fraction c1 comprising trioxane, and a high boiler fraction c2 comprising polyoxymethylene glycols (MGn>1), hemiformals (HFn>1) and polyoxymethylene glycol dimethyl ethers (POMDMEn>2).
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:
Process for preparing high-concentration formaldehyde solutions having a CH2O content of ≧50% by weight from an aqueous formaldehyde solution having a lower CH2O content by evaporation of part of this solution (partial evaporation), in which the aqueous formaldehyde solution is heated to an evaporation temperature T at which the gas phase becomes enriched in water relative to the liquid phase and the gas phase formed is taken off continuously or discontinuously, wherein the evaporation temperature T obeys the relationship: T[° C.]
摘要翻译:通过蒸发具有较低CH 2 O 2含量的甲醛水溶液制备CH 2 O 2含量> 50重量%的高浓度甲醛溶液的方法 该部分溶液(部分蒸发),其中甲醛水溶液被加热到气相相对于液相富集水的蒸发温度T,形成的气相连续或不连续地取出,其中 蒸发温度T遵循以下关系:<?in-line-formula description =“In-line Formulas”end =“lead”?> T [°C。] <°C] (c)= A + Bx(c / 100)+ Cx(c / 100) ) 2 + Dx(c / 100)3和A = + 68.759,B = + 124.77,C = -12.851,D = -10.095,其中c是瞬时 蒸发期间甲醛水溶液的CH 2 O 2 O含量为重量百分比,为20〜99% ht。
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:
A process for preparing trioxane from trioxymethylene glycol dimethyl ether (POMDMEn=3) by converting trioxymethylene glycol dimethyl ether in the presence of an acidic catalyst and subsequent distillative workup of the reaction mixture, comprising the steps of: a) feeding trioxymethylene glycol dimethyl ether (POMDMEn=3) or a mixture comprising trioxymethylene glycol dimethyl ether into a reactor and converting it in the presence of an acidic catalyst to a mixture a comprising trioxane, formaldehyde, water, methylene glycol (MG), polyoxymethylene glycols (MGn>1), methanol, hemiformals (HF), methylal (POMDMEn=1) and polyoxymethylene glycol dimethyl ethers (POMDMEn>1); b) distillatively separating the reaction mixture a into a low boiler fraction b1 comprising trioxane, formaldehyde, water, methylene glycol, methanol, hemiformal (HFn=1), methylal and dioxymethylene glycol dimethyl ether (POMDMEn=2), and a high boiler fraction b2 comprising polyoxymethylene glycols (MGn>1), hemiformals (HFn>1) and polyoxymethylene glycol dimethyl ethers (POMDMEn>2); c) distillatively separating the low boiler fraction b1 into a low boiler fraction c1 comprising formaldehyde, water, methylene glycol, methanol, hemiformal (HFn=1), methylal and dioxymethylene glycol dimethyl ether (POMDMEn=2), and a high boiler fraction c2 comprising trioxane.
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).