摘要:
A process for preparing ultrapure polymers (or solutions thereof) which contain at least 20% by weight of N-vinylpyrrolidone as copolymerized units and have a Fikentscher K value of from 10 to 45 by customary free-radical polymerization in solution and subsequent purification of the solution with or without drying comprises purifying the solutions of the polymers by separating off the low molecular weight impurities by means of ultrafiltration at from 20.degree. to 100.degree. C. and from 1 to 80 bar.
摘要:
The use of solutions of organic polymers for production of carbon membranes suitable for gas separation, and a process for producing carbon membranes suitable for gas separation, comprising the steps of a) coating a porous substrate with solutions of organic polymers, b) drying the polyester coating on the porous substrate by removing the solvent, and c) pyrolyzing the polyester coating on the porous substrate to form the carbon membrane suitable for gas separation, it being possible to conduct any of steps a) to c) or the sequence of steps a) to c) more than once.
摘要:
The present invention relates to a method of conditioning suspended catalysts, wherein at least part of the catalyst-comprising reaction medium is taken from one or more reactors and the suspended, at least partially inactivated catalysts are separated off and purified by means of at least one membrane filtration, with at least one of the membrane filtrations being carried out as a diafiltration.
摘要:
The present invention relates to a process for preparing an aqueous polymer dispersion by free-radical emulsion polymerization of a monomer mixture which comprises N,N-diethylaminoethyl methacrylate, to the polymer dispersion obtainable by this process, and to the use thereof.
摘要:
The present invention relates to a process for the continuous preparation of a 1,3-dioxolan-2-one wherein a discharge from the reaction zone is subjected to a fractionation by means of a semipermeable membrane in order to separate off polymeric by-products.
摘要:
A process for the production of a composite membrane, one or more microporous separation layers comprising a zeolite of the MFI type being produced by hydrothermal synthesis on a porous substrate, wherein one or more additives from the group consisting of linear (C1-C4)-alcohols, ammonia, primary, secondary and tertiary amines having in each case (C1-C4)-alkyl radicals, (C1-C4)-aminoalcohols and (C3-C4)-ketones are added to the synthesis solution for the hydrothermal synthesis.
摘要:
The present invention provides a process for hydrogenating aromatic nitro compounds to the corresponding amines in the presence of hydrogenation catalysts, which comprises using hydrogenation catalysts in which nickel and platinum are present on a support in the form of an alloy having an atomic ratio of nickel to platinum in the alloy of between 30:70 and 70:30.
摘要:
Benzaldehyde dialkyl acetals of the general formula I ##STR1## where R.sup.1 is C.sub.1 -C.sub.6 -alkyl, R.sup.2 is C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkoxy, halogen, cyano or carboxyalkyl where the alkyl group is of 1 to 6 carbon atoms, n is an integer of from 1 to 3 and the radicals R.sup.2 may be identical or different when n is >1, are prepared by electrochemical oxidation of a substituted toluene compound of the general formula II ##STR2## by a process in which a substituted toluene compound II is oxidized in the presence of an alkanol R.sup.1 --OH and of an auxiliary electrolyte in an electrolysis cell, the reaction solution thus obtained is let down outside the electrolysis cell to a pressure which is from 10 mbar to 10 bar lower than the pressure in the electrolysis cell andA) in the batchwise procedure, the gas released from the reaction solution on letting down the latter is separated off and the reaction solution is recycled at least once to the electrolysis cell, subjected to electrolysis, let down, separated from the released gas and then worked up to obtain the product, orB) in the continuous procedure, some of the reaction solution is worked up to obtain the product and the remaining part of the reaction solution is mixed with an amount of the originally used reaction solution which corresponds to the part removed and is recycled to the electrolysis cell, subjected to electrolysis and let down.
摘要:
Salts of polybasic low molecular weight acids are removed from aqueous solutions containing anionic organic compounds by electrodialysis by acidifying the aqueous solution before or during salt removal.
摘要:
The present invention relates to a method for controlling phytopathogenic microorganisms by treating the crop to be protected, the soil or the plant propagation material with an effective amount of copper salt particles which comprise a water-soluble polymer and which have a primary particle diameter of from 1 to 200 nm. The invention also relates to an aqueous suspension of the abovementioned copper salt particles and the use of this suspension in crop protection.