Abstract: In a method and an apparatus furfural is separated from a material stream (3) which is formed in a treatment of a pretreated wood based material (1). The material stream (3) which comprises at least furfural is introduced to a separation column (5). A top vapor condensate (6) is introduced from a top end of the separation column (5) to a decanter (10) in which two liquid phases (9,11) are separated from each other. An organic phase (9) which comprises at least furfural is recovered, and an aqueous phase (11) is supplied as a reflux to the separation column (5). Further, the invention relates to a furfural based product and chemical product and a use of the organic phase.

Abstract: Process for preparing polyoxymethylene dimethyl ethers having ?3 oxymethylene units (OMEn?3), comprising the steps: (i) introduction of formaldehyde, methanol and water into a reactor R and reaction to give a reaction mixture containing formaldehyde, water, methylene glycol, polyoxymethylene glycols, methanol, hemiformals, methylal (OMEn=1) and polyoxymethylene dimethyl ethers (OMEn>1); (ii) introduction of the reaction mixture into a reactive distillation column K1 and separation into a low boiler fraction F1 containing formaldehyde, water, methylene glycol, polyoxymethylene glycols, methanol, hemiformals, methylal (OMEn=1) and polyoxymethylene dimethyl ethers having from 2 to 3 oxymethylene units (OMEn=2-3) and a high boiler fraction F2 containing polyoxymethylene dimethyl ethers having more than two oxymethylene units (OMEn?3).

Abstract: The invention relates to a continuous process to make and isolate methylal by reacting formaldehyde and methanol with an acid catalyst under at least partial formation of methylal and water, to form a mixture M2 comprising formaldehyde, methanol, methylal, and water, separating the said mixture M2 in a distillation column B into three distinct product streams, one being a distillate taken from the column head BH which is rich in methylal, one taken from the column bottom stream BB being almost pure water, and one taken from the side of the column B below the reaction zone which stream is rich in methanol, characterised in that the ratio of the amount of substance of methanol to the amount of substance of formaldehyde in the mixture M1 is at least 3 mol/mol, and to an apparatus to be used with this process.

Abstract: The invention relates to a continuous process to make and isolate methylal by reacting formaldehyde and methanol with an acid catalyst under at least partial formation of methylal and water, to form a mixture M2 comprising formaldehyde, methanol, methylal, and water, separating the said mixture M2 in a distillation column B into three distinct product streams, one being a distillate taken from the column head BH which is rich in methylal, one taken from the column bottom stream BB being almost pure water, and one taken from the side of the column B below the reaction zone which stream is rich in methanol, characterised in that the ratio of the amount of substance of methanol to the amount of substance of formaldehyde in the mixture M1 is at least 3 mol/mol, and to an apparatus to be used with this process.

Abstract: A process for removing acid gases from a fluid stream in which a) the fluid stream is treated with an absorption liquid which comprises at least one amine, a stripping aid, and water, wherein the stripping aid is selected from water-miscible liquids, the boiling temperature of which at atmospheric pressure is lower than that of water, b) the treated fluid stream is treated with a liquid aqueous phase in order to convert entrained stripping aid at least in part to the aqueous phase, c) the loaded aqueous phase is heated in order to expel the stripping aid at least in part, and d) the regenerated aqueous phase is cooled and at least in part recycled to step b). The stripping aid promotes the regeneration of the absorbent by stripping. Emissions of the stripping aid via the treated fluid stream are avoided by the treated fluid stream being scrubbed with a liquid aqueous phase.

Abstract: A process for preparing polyoxymethylene dialkyl ethers of the formula H2m+1CmO(CH2O)nCmH2m+1 where n=2-10, m, identically or differently,=1 or 2, in which a dialkyl ether selected from dimethyl ether, methyl ethyl ether and diethyl ether, and trioxane are fed into a reactor and reacted in the presence of an acidic catalyst, the amount of water introduced into the reaction mixture by the dialkyl ether, trioxane and/or the catalyst being <1% by weight based on the reaction mixture.

Abstract: A process for removing acid gases from a fluid stream in which a) the fluid stream is treated with an absorption liquid which comprises at least one amine, a stripping aid, and water, wherein the stripping aid is selected from water-miscible liquids, the boiling temperature of which at atmospheric pressure is lower than that of water, b) the treated fluid stream is treated with a liquid aqueous phase in order to convert entrained stripping aid at least in part to the aqueous phase, c) the loaded aqueous phase is heated in order to expel the stripping aid at least in part, and d) the regenerated aqueous phase is cooled and at least in part recycled to step b). The stripping aid promotes the regeneration of the absorbent by stripping. Emissions of the stripping aid via the treated fluid stream are avoided by the treated fluid stream being scrubbed with a liquid aqueous phase.

Abstract: A thermodynamic machine for the absorption and emission of heat at different temperatures has at least one thermodynamic device with at least one membrane separating a gas phase and a liquid phase provided for transport of heat, wherein the at least one membrane is permeable for at least one component contained in the gas and liquid phases. The at least one membrane is a porous membrane or a solution diffusion membrane or a modification of the porous membrane or a modification of the solution diffusion membrane.

Abstract: 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.

Abstract: 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

Abstract: 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

Abstract: A process for removing trioxane from a use stream I of formaldehyde, trioxane and water, by a) providing a use stream I of formaldehyde as the main component and trioxane and water as the secondary components, b) mixing the use stream I with a recycle stream VII to obtain a feed stream Ia, c) distilling the use stream Ia in a first distillation stage to obtain a stream II of formaldehyde as the main component and water as the secondary component, and a stream III of trioxane as the main component and water and formaldehyde as the secondary components, d) distilling the stream III in a second distillation stage having a pressure higher than in the first distillation stage, to obtain a stream IV of trioxane and a stream V of trioxane as the main component and water and formaldehyde as the secondary components, e) distilling the stream V in a third distillation stage to obtain a stream VI of water and the recycle stream VII of trioxane as the main component and water and formaldehyde as the secondary components

Abstract: A process for preparing tri- and tetraoxymethylene glycol dimethyl ether (POMDMEn=3,4) by reacting formaldehyde with methanol and subsequently working up the reaction mixture by distillation, consisting of: a) feeding aqueous formaldehyde solution and methanol into a reactor and reacting to give a mixture including formaldehyde, water, methylene glycol (MG), polyoxymethylene glycols (MGn>1), methanol, hemiformals (HF), methylal (POMDMEn=1) and polyoxymethylene glycol dimethyl ethers (POMDMEn>1); b) feeding the reaction mixture a into a first distillation column and separating into a low boiler fraction b1 and a high boiler fraction b2 including formaldehyde, water, methanol, MGn>1, HF and POMDMEn>1; c) feeding the high boiler fraction b2 into a second distillation column and separating into a low boiler fraction c1 including formaldehyde, water, MG, MGn>1, methanol, HF, di-, tri- and tetraoxymethylene glycol dimethyl ether (POMDMEn=2,3,4), and a high boiler fraction c2; d) feeding the low boile

Abstract: Processes for preparing tri- and tetraoxymethylene glycol dimethyl ether (POMDMEn=3,4) include feeding a reaction mixture of an aqueous formaldehyde solution and methanol into a reactive evaporator and separating into a first low boiler fraction and a first high boiler fraction, recycling the first high boiler fraction into the reactor, feeding the first low boiler fraction into a first distillation column and separating into a second low boiler fraction and a second high boiler fraction, recycling the second high boiler fraction into the reactive evaporator, feeding the second low boiler fraction into a second distillation column and separating into a third low boiler fraction and a third high boiler fraction, feeding the third high boiler fraction into a phase separation apparatus and separating into an aqueous phase and an organic phase, and feeding the organic phase into a third distillation column and separating into a low and high boiler fractions.

Abstract: An absorption medium for deacidifying fluid streams which has improved oxidation stability includes at least one aliphatic amine, and at least one non-hydroquinoid antioxidant. The absorption medium may be employed in deacidifying a fluid stream, in particular an oxygen-containing fluid stream, when the fluid stream is brought into intimate contact with the absorption medium in at least one absorption step.

Abstract: 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.

Abstract: A process for preparing tri- and tetraoxymethylene glycol dimethyl ether (POMDMEn=3,4) by reacting formaldehyde with methanol and subsequently working up the reaction mixture by distillation, comprising the steps of.

Abstract: A process for preparing polyoxymethylene dialkyl ethers of the formula H2m+1CmO(CH2O)nCmH2m+1 where n=2-10, m, identically or differently,=1 or 2, in which a dialkyl ether selected from dimethyl ether, methyl ethyl ether and diethyl ether, and trioxane are fed into a reactor and reacted in the presence of an acidic catalyst, the amount of water introduced into the reaction mixture by the dialkyl ether, trioxane and/or the catalyst being <1% by weight based on the reaction mixture.

Abstract: A process for preparing tri- and tetraoxymethylene glycol dimethyl ether (POMDMEn=3,4) by reacting formaldehyde with methanol and subsequently working up the reaction mixture by distillation, comprising the steps of: a) feeding aqueous formaldehyde solution and methanol into a reactor and reacting; b) feeding the reaction mixture a into a reactive evaporator and separating into a low boiler fraction b1 comprising formaldehyde, water, methanol, methylene glycol, polyoxymethylene glycols, hemiformals, methylal and polyoxymethylene glycol dimethyl ethers (POMDMEn>1), and a high boiler fraction b2, and recycling the high boiler fraction b2 into the reactor (step a)); c) feeding the low boiler fraction b1 into a first distillation column and separating into a low boiler fraction c1 comprising formaldehyde, water, methylene glycol, methanol, hemiformals, methylal, di-, tri- and tetraoxymethylene glycol dimethyl ether (POMDMEn=2,3,4), and a high boiler fraction c2, and recycling the high boiler fraction c2 into

Abstract: 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.