摘要:
Polyisocyanates are produced by reacting a polyamide solution with a phosgene solution. After the product polyisocyanate has been recovered, the solvent or a portion of the solvent employed is treated with crosslinked polymers insoluble in the solvent which polymers contain primary and/or secondary alcoholic hydroxyl groups and/or primary and/or secondary amino groups. After treatment, the polymer and any reaction products are removed. The solvent may then be reused. Preferred solvents are chlorobenzene and o-dichlorobenzene. The preferred polymers are bead polymers or bead copolymers of (meth)acrylic acid or styrene/divinyl benzene copolymer.
摘要:
The metallization of porous solid bodies, such as, for example, ion exchange materials, by loading the surfaces of the metal-free substrates with transition metal ions and subsequently treating them with reducing agents can be improved by activating the substrates, before or after the loading with metal ions, with elements of group 1 or 8 of the periodic table or compounds thereof and sensitizing any activating ions still present. The metallization products are useful hydrogenation catalysts.
摘要:
Tert.-olefins are obtained in high purity by cleavage of their alkyl ethers, when the catalysts used for this purpose are styrene/divinylbenzene resins which contain sulphonic acid groups and have a macroporous structure and the polymer matrix of which has an internal surface area of at least 400 m.sup.2 /g, a pore volume (porosity) of 0.6-2.5 ml/g and a mean pore diameter of 40-1000 .ANG.. These catalysts show long service lives.
摘要:
The invention relates to a new process for the preparation of strongly acid cation exchangers loaded with catalytically active metals by loading the cation exchangers with a solution of a salt of the catalytically active metal and reducing the cation exchangers loaded with metal ions, according to which the loading of the cation exchangers is carried out at temperatures from 50.degree. to 120.degree. C. and formic acid is used as the reducing agent; the invention also relates to the catalyst resins which can be obtained by the process.
摘要:
Known antibacterial quinolonecarboxylic acid derivatives such as ciprofloxacin are administered to animals in their food in the form of weak cation exchangers loaded therewith. The taste is much improved and the animals accept the material more readily.
摘要:
In the removal of pure aromatics from aromatic-containing hydrocarbon mixtures by liquid-phase extraction or extractive distillation using a selective solvent, the specific cost of separation can be reduced at the same yield of aromatics or the yield of aromatics can be increased at the same specific cost of separation if the liquid-phase extraction or the extractive distillation is carried out in the presence of a reactive solid. At the same time, substantially aromatic-free raffinates are obtained.
摘要:
A process for the preparation of a bifunctional anion exchange resin by partial quaternization of a weakly basic anion exchanger containing tertiary amino groups which process comprises (a) partially loading the weakly basic anion exchanger with a strong acid and (b) quaternizing the partially loaded anion exchanger by means of a customary alkylating agent.
摘要:
In the process for recovering gallium from aqueous, alkaline solutions by adsorption of the gallium on to bead-polymerized synthetic resins impregnated with 8-hydroxyquinolines and elution thereof with aqueous acids, the synthetic resins employed according to the invention are macroporous polydivinylbenzene or macroporous divinylbenzene copolymers which have been obtained by bead polymerization of divinylbenzene or mixtures of aromatic mono-, di- and/or trivinylbenzenes containing at least 50% by weight of divinylbenzene, in the presence of methyl isobutyl ketone, and which have been loaded with 160-190 g of Kelex 100 per liter of resin; in addition the resin is washed with sodium hydroxide solution after the elution step and before the commencement of each individual service cycle.
摘要:
The invention relates to new bead-shaped crosslinked macroporous copolymers containing epoxide groups and basic amino groups, which are obtainable by reacting polymerizable glycidyl compounds, before or during free radical bead polymerization, which is carried out in the presence of agents which impart porosity and, if appropriate, with the addition of polyvinyl compounds which can be polymerized by free radical polymerization, with amines which are capable of reacting with at least two epoxide groups, a process for their preparation and their use, for example, for binding biologically active substances, for the preparation of strongly basic anion exchangers and hydrophilic chromatography resins for biomaterials.
摘要:
Cyclic N-vinylacylamines are prepared by heating carbonic acid esters of cyclic N-2-hydroxyethylacylamines in the presence of a catalytic amount of alkali or alkaline earth metal compound having an alkaline reaction and subsequently distilling the reaction mixture.Cyclic N-vinylacylamines are valuable precursors for preparing plant protection agents and medicaments and serve as polymerization and copolymerization components for preparing plastics, surface coatings, paints and ion exchange materials.