Abstract:
The present invention relates to a process for preparing cyclic compounds having at least eight carbon atoms and at least one keto group, to the cyclic compounds obtained by this process and to the use thereof, in particular as fragrance or for providing a fragrance.
Abstract:
A single-screw extruder for changing a morphology of a superabsorbent polymer, specifically a polymer gel. The single-screw extruder has an input aperture, a channel, a screw and an output aperture. The screw has a pitch value of a pitch of the screw flights along the conveying zone of the channel, where the channel has a mixing-element arrangement with at least one mixing element which protrudes into the channel of the single-screw extruder and which is configured for the mixing of the SAP polymer gel.
Abstract:
A process for producing water-absorbing polymer particles is provided, comprising a) a polymerization step in which an aqueous monomer solution comprising at least one ethylenically unsaturated monomer M which bears acid groups and may have been at least partly neutralized and at least one crosslinker is polymerized to obtain an aqueous polymer gel; b) a pelletization step in which the aqueous polymer gel having a solids content of 35 to 70% by weight and a temperature of 75 to 125° C. is forced from a high-pressure zone through a die plate into a low-pressure zone and pellets are obtained, the pressure differential between the high-pressure zone and the low-pressure zone being 4 to less than 14 bar and the orifice ratio of the die plate being 30 to 80%; c) a drying step in which the pellets are dried to a moisture content of less than 10% by weight; d) a grinding step and a classifying step to obtain water-absorbing polymer particles; and e) surface crosslinking of the water-absorbing polymer particles. The water-absorbing polymer particles have a high swell rate and a high retention capacity combined with a favorable ratio of permeability of the swollen gel bed SFC to centrifuge retention capacity CRC.
Abstract:
The present invention relates to a process for preparing cyclohexane by isomerizing a hydrocarbon mixture (HM1) comprising methylcyclopentane (MCP) in the presence of a catalyst. The catalyst is preferably an acidic ionic liquid. The starting material used is a stream (S1) which originates from a steamcracking process. The hydrocarbon mixture (HM1) obtained from this stream (S1) in an apparatus for aromatics removal has a reduced aromatics content compared to stream (S1), and (HM1) may optionally also be (virtually) free of aromatics. Depending on the type and amount of the aromatics remaining in the hydrocarbon mixture (HM1), especially in the case that benzene is present, the isomerization may additionally be preceded by performance of a hydrogenation of (HM1). In addition, depending on the presence of other components of (HM1), further purification steps may optionally be performed prior to or after the isomerization or hydrogenation. High-purity (on-spec) cyclohexane is preferably isolated from the hydrocarbon mixture (HM2) obtained in the isomerization, the specifications being, for example, those applicable to the use of the cyclohexane for the preparation, known to those skilled in the art, of caprolactam.
Abstract:
A process for producing water-absorbing polymer particles is provided, comprising a) a polymerization step in which an aqueous monomer solution comprising at least one ethylenically unsaturated monomer M which bears acid groups and may have been at least partly neutralized and at least one crosslinker is polymerized to obtain an aqueous polymer gel; b) a pelletization step in which the aqueous polymer gel having a solids content of 35 to 70% by weight and a temperature of 75 to 125° C. is forced from a high-pressure zone through a die plate into a low-pressure zone and pellets are obtained, the pressure differential between the high-pressure zone and the low-pressure zone being 4 to less than 14 bar and the orifice ratio of the die plate being 30 to 80%; c) a drying step in which the pellets are dried to a moisture content of less than 10% by weight; d) a grinding step and a classifying step to obtain water-absorbing polymer particles; and e) surface crosslinking of the water-absorbing polymer particles. The water-absorbing polymer particles have a high swell rate and a high retention capacity combined with a favorable ratio of permeability of the swollen gel bed SFC to centrifuge retention capacity CRC.
Abstract:
Described is a process for the treatment of a gas stream containing nitrogen oxides. The process comprises the steps of: (1) providing a gas stream containing one or more nitrogen oxides; (2) contacting the gas stream provided in step (1) with a transition metal containing zeolitic material having a BEA-type framework structure for reacting one or more of the nitrogen oxides; wherein the zeolitic material is obtainable from an organotemplate-free synthetic process. Also described is an apparatus for the treatment of a gas stream comprising containing nitrogen oxides.
Abstract:
The present invention relates to a process for preparing cyclohexane by isomerizing a hydrocarbon mixture (HM1) comprising methylcyclopentane (MCP) in the presence of a catalyst. The catalyst is preferably an acidic ionic liquid. The starting material used is a stream (S1) which originates from a steamcracking process. The hydrocarbon mixture (HM1) obtained from this stream (S1) in an apparatus for aromatics removal has a reduced aromatics content compared to stream (S1), and (HM1) may optionally also be (virtually) free of aromatics. Depending on the type and amount of the aromatics remaining in the hydrocarbon mixture (HM1), especially in the case that benzene is present, the isomerization may additionally be preceded by performance of a hydrogenation of (HM1). In addition, depending on the presence of other components of (HM1), further purification steps may optionally be performed prior to or after the isomerization or hydrogenation. High-purity (on-spec) cyclohexane is preferably isolated from the hydrocarbon mixture (HM2) obtained in the isomerization, the specifications being, for example, those applicable to the use of the cyclohexane for the preparation, known to those skilled in the art, of caprolactam.