摘要:
The invention relates to a process for the selective hydrogenation of alkynes and dienes in C2-C5+-olefin mixtures,—in C2- or C3-streams of the olefin preparation by cracking. The method comprises conducting the hydrogenation in the presence of a catalyst particle comprising (a) a metal of the tenth group of the Periodic Table, (b) a metal of the eleventh group of the Periodic Table and (c) optionally a compound of a metal of the first or second group of the Periodic Table. Components (a) and (b), and optionally (c), are applied to a support selected from the group consisting of silica, titanium dioxide, zirconium oxides, spinels, zinc aluminates, zinc titanate, aluminosilicates and mixtures thereof. The metal of the eleventh group is distributed homogeneously over the cross-section of the catalyst particle, and the metal of the tenth group is present in an edge layer close to the surface of the catalyst particle.
摘要:
A catalyst for the selective hydrogenation of alkynes and dienes in C2-C5+-olefin mixtures is described.These catalysts contain (a) a metal of the tenth group of the Periodic Table, (b) a metal of the eleventh group of the Periodic Table and (c) if required, a compound of a metal of the first or second group of the Periodic Table, these metals being applied to a support which is selected from the group consisting of silica, titanium dioxide, zirconium oxides, spinels, zinc aluminates, zinc titanates or mixtures of these substances, and the metal of the eleventh group being distributed homogeneously over the cross section of the catalyst particle and the metal of the tenth group being present in the edge layer close to the surface of the catalyst particle. Such a catalyst is prepared by applying the metal of the eleventh group, preferably during the preparation of the support itself, by impregnation with a solution of a suitable metal salt.
摘要:
A catalyst for the selective hydrogenation of alkynes and dienes in C2-C5+-olefin mixtures is described. These catalysts contain (a) a metal of the tenth group of the Periodic Table, (b) a metal of the eleventh group of the Periodic Table and (c) if required, a compound of a metal of the first or second group of the Periodic Table, these metals being applied to a support which is selected from the group consisting of silica, titanium dioxide, zirconium oxides, spinels, zinc aluminates, zinc titanates or mixtures of these substances, and the metal of the eleventh group being distributed homogeneously over the cross section of the catalyst particle and the metal of the tenth group being present in the edge layer close to the surface of the catalyst particle. Such a catalyst is prepared by applying the metal of the eleventh group, preferably during the preparation of the support itself, by impregnation with a solution of a suitable metal salt.
摘要:
A process for removing high boilers from crude caprolactam which comprises high boilers, caprolactam and in some cases low boilers, and which has been obtained by a) reacting 6-aminocapronitrile with water to give a reaction mixture b) removing ammonia and unconverted water from the reaction mixture to obtain crude caprolactam, which comprises c) feeding the crude caprolactam to a distillation apparatus to obtain a first substream via the top as a product and a second substream via the bottom, by setting the pressure in the distillation in such a way that the bottom temperature does not go below 170° C., and adjusting the second substream in such a way that the caprolactam content of the second substream is not less than 10% by weight, based on the entire second substream.
摘要:
A process for distillative removal of ammonia from solutions (I) which include a lactam and ammonia comprises effecting said removal in a distillation apparatus (a) at an absolute pressure of less than 10 bar.
摘要:
A process for preparing aliphatic alpha, omega-diamines by hydrogenation of aliphatic alpha, omega-dinitriles in the presence of a catalyst comprises using a hydrogenation catalyst comprising (a) iron or a compound based on iron or mixtures thereof, (b) from 0.001 to 0.3% by weight based on (a) of a promoter based on 2, 3, 4 or 5 elements selected from the group consisting of aluminum, silicon, zirconium, titanium and vanadium, and also (c) from 0 to 0.3% by weight based on (a) of a compound based on an alkali and/or alkaline earth metal.
摘要:
The iron-containing catalyst suitable for use as a catalyst contains a) iron or a mixture containing iron and an iron-based compound. The iron has an average crystallite size ranging from 1-35 nm measured by X-ray diffraction.
摘要:
A process for reducing the level of an aliphatic monounsaturated amine (IV) in a mixture (V) containing an aminonitrile (I) or a diamine (II) or a dinitrile (III) or mixtures thereof as well as said mine (IV) by a) reacting said mixture (V) with an anionic nucleophile (VI) which contains a nucleophilic atom selected from the group consisting of oxygen, nitrogen and sulfur, which is capable of taking up an H+ ion to form an acid having a pKa value in the range from 7 to 11, as measured in water at 25° C., and which has a relative nucleophilicity, as measured in methyl perchlorate/methanol at 25° C., in the range from 3.4 to 4.7 when said nucleophilic atom is oxygen, in the range from 4.5 to 5.8 when said nucleophilic atom is nitrogen, and in the range from 5.5 to 6.8 when said nucleophilic atom is sulfur, in an amount in the range from 0.01 to 10 mol per mole of said amine (IV) in said mixture (V) at a temperature in the range from 50 to 200° C. to obtain a mixture (VII), b) distilling said aminonitrile (I) or said diamine (II) or said dinitrile (III) or mixtures thereof from said mixture (VII) at a temperature in the range from 50 to 200° C. and at a pressure in the range from 0.1 to 100 kPa to obtain a bottom product (VIII), which comprises c) distilling an aminonitrile (I) or diamine (II) or dinitrile (III) or mixtures thereof from said bottom product (VIII) at a temperature which is lower than that chosen in step b).
摘要:
A process for purifying crude caprolactam which has been obtained by 1) converting a mixture (I) comprising 6-aminocapronitrile and water to a mixture (II) comprising caprolactam, ammonia, water, high boilers and low boilers in the presence of a catalyst, then 2) removing ammonia from mixture (II) to obtain a mixture (III) comprising caprolactam, water, high boilers and low boilers, then 3) completely or partly removing water from mixture (III) to obtain crude caprolactam (IV) comprising caprolactam, high boilers and low boilers, which comprises a) feeding the crude caprolactam and an inorganic acid which has a boiling point above the boiling point of caprolactam under the distillation conditions of the following steps b) to h) to a first distillation apparatus C1, b) distilling the crude caprolactam and the inorganic acid in the first distillation apparatus C1, and removing a first substream in the bottom region and a second substream in the top region of the distillation apparatus C1, c) feeding the second substream from step b) to a second distillation apparatus C2, d) distilling the second substream from step b) in the second distillation apparatus C2, and removing a first substream in the bottom region and a second substream in the top region of the distillation apparatus C2, e) feeding the first substream from step d) to a third distillation apparatus C3, f) distilling the first substream from d) in the third distillation apparatus C3, and removing a first substream in the bottom region and purified caprolactam in the top region of distillation apparatus C3, and g) feeding the first substream from step f) to the first distillation apparatus C1.
摘要:
Higher &agr;,&bgr;-unsaturated alcohols are prepared by monoethynylation of a ketone by the NH3/KOH method, if desired hydrogenation of the acetylene alcohol in the presence of hydrogen over a Pd-containing thin layer catalyst, purifying distillation of the hydrogenation product, preferably in a dividing wall column with recirculation of the unreacted ketone to the ethynylation step, and, if desired, preparation of higher alcohols having in each case 5 more carbon atoms in the chain by reacting the alcohols prepared by monoethynylation and, if desired, partial hydrogenation with alkyl acetoacetates diketene in a Carroll reaction to form ketones and using these as starting materials for the steps ethynylation, optional hydrogenation and fractional distillation.