摘要:
Copolymers of acrylamide or methacrylamide, suitably modified with appropriate percentages of units deriving from comonomers of a hydrophobic nature and comonomers containing a positively charged ionic group, which are capable of effectively reducing the water permeability of a porous medium.
摘要:
Copolymers of acrylamide or methacrylamide, suitably modified with appropriate percentages of units deriving from comonomers of a hydrophobic nature and comonomers containing a positively charged ionic group, which are capable of effectively reducing the water permeability of a porous medium.
摘要:
A process is described for the preparation of a heterogeneous catalyst containing rhecnium as active component and C)an inert carrier medium. characterized in that said inert carrier is previously treated with a silanizing compound containing chlorine, before the laying of the active component on the carrier, and the activation of the heterogeneous catalyst takes place by means of thermal treatment followed by a rapid final cooling. The catalyst is particularly active in metathesis reactions of olefins.
摘要:
Phosphino oxide group containing compounds useful as flame retardant additives, having the general formula (I): ##STR1## wherein: X and X.sub.1 represent a hydrogen atom or, when taken jointly, they represent an NR.sub.1 moiety in which R.sub.1 stands for a hydrogen atom; a linear or branched aliphatic C.sub.1 -C.sub.5 moiety; a linear or branched C.sub.2 -C.sub.6 acyl moiety; a phenyl moiety;R represents a cyclic or polycyclic C.sub.4 -C.sub.9 moiety containing two carboxy groups, possibly esterified with univalent alcohols or glycols, or transformed into anhydrides, or two hydroxy groups.
摘要:
A heterogeneous catalyst is described, active in the metathesis reaction of olefins comprising alumina as inert carrier and a rhenium compound as active component, characterized in that rhenium is present in an amount of less than 5% by weight with respect to the total preferably from 1 to 4% by weight, and the inert carrier is impregnated with at least one inorganic halide selected from FeCl3, CuCl2, TiCl4, RuCl3, ZnCl2 and NH4Cl, and/or the corresponding bromides or iodides and, subsequently, treated at a high temperature.
摘要:
Metallocene complexes of a metal M selected from titanium, zirconium and hafnium, comprising at least one anionic group A containing an .eta..sup.5 -cyclopentadienyl ring co-ordinated with the metal M, wherein the anionic group is substituted in at least one position of the cyclopentadienyl ring with a radical having the formula:Ph*--(CR.sup.6 R.sup.7).sub.nwherein: R.sup.6 and R.sup.7 are independently hydrogen, halogen or a C.sub.1 -C.sub.4 alkyl group, preferably hydrogen, "n" is 0 or 1, preferably 1, Ph* is a C.sub.6 -C.sub.14 group comprising an aromatic ring linked to --CR.sup.6 R.sup.7 -- or to A and substituted with at least one and up to a maximum of three electron-attractor groups, on the condition that, when A is an .eta..sup.5 -indenyl group and "n" is 0, at least one Ph group is linked to A in position 1 or 3 of indenyl.These complexes can be used in (co)polymerization processes of .alpha.-olefins, possibly in the presence of a suitable co-catalyst, for the production of polyolefins with a very high molecular weight.
摘要:
Disclosed is the synthesis of terminal diols, which are organic intermediates used in order to produce polymeric materials, by starting from terminal diolefins, which synthesis is based on the oxidation of diolefins to yield diepoxides, in a double-phase aqueous-organic system with hydrogen peroxide and in the presence of catalysts soluble in the organic phase, followed by a reaction of reduction of the resulting diepoxides.