摘要:
Vinyl monomers are polymerized in the aqueous phase in the presence of at least one N-oxyl compound of a secondary amine, having no hydrogen atoms bonded to the &agr; carbon atoms. This process substantially eliminates deposits on reactor surfaces.
摘要:
A monomer composition, which contains A) vinyl-containing monomers in which a heteroatom selected from the group consisting of the halogens, nitrogen, oxygen, sulfur and silicon is present on the vinyl group, and B) a compound or a mixture of compounds of the formula II where R4 is methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl, sec-butyl, tert-butyl or trimethylsilyl.
摘要:
An article having a metallic surface treated with polymeric complexing agent is described. Particularly suitable polymeric complexing agents are phosphonoalkylated polyethyleneimines and/or carboxyalkylated polyethyleneimines and/or vinylimidazole polymers. As a rule, the treated metallic surface forms the total inner surface or a part of the inner surface of a process apparatus or of a container. The surface is protected by the treatment, in particular from the adhesion of polymer.
摘要:
Disclosed is a process for pressurizing ethylenically unsaturated monomers to 200-5000 bar in the absence of a polymerization initiator, which comprises effecting said pressurizing in the presence of nitroxyl compounds of the formula I where R1 and R2 are singly C1-C4-alkyl or combine with the joining carbon atom to form a 5- or 6-membered saturated hydrocarbon ring, R3 is C1-C4-alkyl, and R4 is hydrogen or C1-C12-alkyl. Also disclosed are a process for preparing copolymers by such pressurization and subsequent polymerization and copolymers obtainable thereby.
摘要:
A process of free-radically initiated aqueous emulsion polymerization, in which monomers are polymerized in the presence of a N-oxyl radical and by means of special free-radical polymerization initiators at more than 100° C. and at pressures above the vapor pressure of the polymerization mixture.
摘要:
Substance mixtures comprising (A) vinyl-containing compounds, (B) an active amount of a mixture inhibiting the premature polymerization of the vinyl-containing compounds, comprising (i) at least one N-oxyl compound of a secondary amine which carries no hydrogen atoms on the &agr;-C atoms, and (ii) at least one iron compound, (C) if appropriate nitro compounds, and (D) if appropriate costabilizers, a process for inhibiting the premature polymerization of vinyl-containing compounds (A) and the use of mixture (B), if appropriate as a mixture with nitro compounds (C) and/or costabilizers (D), for inhibiting the premature polymerization of free radical polymerizable compounds and for stabilizing organic materials against the damaging action of free radicals.
摘要:
Mixtures contain(A) vinyl-containing monomers, and(B) an effective amount of a mixture inhibiting the premature polymerization of the vinyl-containing monomers during the purification or distillation and containing(i) from 0.05 to 4.5% by weight, based on the total mixture (B), of at least one N-oxyl compound of a secondary amine which carries no hydrogen atoms on the .alpha.-carbon atoms and(ii)from 99.95 to 95.5% by weight, based on the total mixture (B), of at least one nitro compound,and a mixture (B) is used for inhibiting the premature polymerization of monomers.
摘要:
A process for compressing ethylenically unsaturated monomers at a pressure of 200-5000 bar in the absence of a polymerization initiator comprises carrying out compression in the presence of a sterically hindered amine derivative.
摘要:
The present invention provides a process for the free radical polymerization of one or more ethylenically unsaturated monomers, said process comprising polymerizing one or more ethylenically unsaturated monomers in the presence of one or more N-oxyl radicals of formula II, wherein X is S, NR5, O, SO or SO2, R5 is C1-C20-alkyl or C5-C8-cycloalkyl and R3 and R4 independently of one another, are C1-C4-alkyl, phenyl, naphthyl or an aromatic five-membered ring, or R3 and R4 together are —(CH2)o— and p and o, independently of one another, are an integer from 2 to 7.
摘要:
In a process for stabilizing chemical compounds having at least one ethylenically unsaturated bond to undesired free radical polymerization, a nitroxyl radical and a chemical compound containing phosphorus in chemically bonded form are added to the unsaturated compound present as pure substance or as a component of a mixture.